Merge from Chromium at DEPS revision r205460

This commit was generated by merge_to_master.py.

Change-Id: I4a744a5e426bd3bb378d887cfa56fe054742a540

114 files changed, 5080 insertions, 3882 deletions

diff --git a/native_client_sdk/src/build_tools/build_sdk.py b/native_client_sdk/src/build_tools/build_sdk.py
index 5b793536a7..9839dff510 100755
--- a/native_client_sdk/src/build_tools/build_sdk.py
+++ b/native_client_sdk/src/build_tools/build_sdk.py
@@ -54,7 +54,9 @@ import oshelpers
 CYGTAR = os.path.join(NACL_DIR, 'build', 'cygtar.py')
 
 NACLPORTS_URL = 'https://naclports.googlecode.com/svn/trunk/src'
-NACLPORTS_REV = 757
+NACLPORTS_REV = 774
+
+GYPBUILD_DIR = 'gypbuild'
 
 options = None
 
@@ -434,21 +436,30 @@ TOOLCHAIN_LIBS = {
 
 
 def GypNinjaInstall(pepperdir, platform, toolchains):
-  build_dir = 'gypbuild'
+  build_dir = GYPBUILD_DIR
   ninja_out_dir = os.path.join(OUT_DIR, build_dir, 'Release')
   tools_files = [
-    ['dump_syms', 'dump_syms'],
     ['sel_ldr', 'sel_ldr_x86_32'],
-    ['ncval_x86_32', 'ncval_x86_32'],
-    ['ncval_arm', 'ncval_arm'],
+    ['ncval_new', 'ncval'],
     ['irt_core_newlib_x32.nexe', 'irt_core_x86_32.nexe'],
     ['irt_core_newlib_x64.nexe', 'irt_core_x86_64.nexe'],
   ]
+  if sys.platform not in ['cygwin', 'win32']:
+    minidump_files = [
+      ['dump_syms', 'dump_syms'],
+      ['minidump_dump', 'minidump_dump'],
+      ['minidump_stackwalk', 'minidump_stackwalk']
+    ]
+    tools_files.extend(minidump_files)
+
+  # TODO(binji): dump_syms doesn't currently build on Windows. See
+  # http://crbug.com/245456
+  if platform != 'win':
+    tools_files.append(['dump_syms', 'dump_syms'])
 
   if platform != 'mac':
     # Mac doesn't build 64-bit binaries.
     tools_files.append(['sel_ldr64', 'sel_ldr_x86_64'])
-    tools_files.append(['ncval_x86_64', 'ncval_x86_64'])
 
   if platform == 'linux':
     tools_files.append(['nacl_helper_bootstrap',
@@ -473,10 +484,10 @@ def GypNinjaInstall(pepperdir, platform, toolchains):
       tc_dir = 'tc_' + tc
       lib_dir = 'lib' + archname
       if archname == 'arm':
-        build_dir = 'gypbuild-arm'
+        build_dir = GYPBUILD_DIR + '-arm'
         tcdir = '%s_arm_%s' % (platform, tc)
       else:
-        build_dir = 'gypbuild'
+        build_dir = GYPBUILD_DIR
         tcdir = '%s_x86_%s' % (platform, tc)
 
       ninja_out_dir = os.path.join(OUT_DIR, build_dir, 'Release')
@@ -502,22 +513,18 @@ def GypNinjaBuild_NaCl(platform, rel_out_dir):
   out_dir_arm = MakeNinjaRelPath(rel_out_dir + '-arm')
   GypNinjaBuild('ia32', gyp_py, nacl_core_sdk_gyp, 'nacl_core_sdk', out_dir)
   GypNinjaBuild('arm', gyp_py, nacl_core_sdk_gyp, 'nacl_core_sdk', out_dir_arm)
-  GypNinjaBuild('ia32', gyp_py, all_gyp, 'ncval_x86_32', out_dir)
-  GypNinjaBuild(None, gyp_py, all_gyp, 'ncval_arm', out_dir)
+  GypNinjaBuild('ia32', gyp_py, all_gyp, 'ncval_new', out_dir)
 
   if platform == 'win':
     NinjaBuild('sel_ldr64', out_dir)
-    NinjaBuild('ncval_x86_64', out_dir)
   elif platform == 'linux':
     out_dir_64 = MakeNinjaRelPath(rel_out_dir + '-64')
     GypNinjaBuild('x64', gyp_py, nacl_core_sdk_gyp, 'sel_ldr', out_dir_64)
-    GypNinjaBuild('x64', gyp_py, all_gyp, 'ncval_x86_64', out_dir_64)
 
-    # We only need sel_ldr and ncval_x86_64 from the 64-bit out directory.
+    # We only need sel_ldr from the 64-bit out directory.
     # sel_ldr needs to be renamed, so we'll call it sel_ldr64.
     files_to_copy = [
       ('sel_ldr', 'sel_ldr64'),
-      ('ncval_x86_64', 'ncval_x86_64'),
       ('nacl_helper_bootstrap', 'nacl_helper_bootstrap64'),
     ]
 
@@ -528,10 +535,16 @@ def GypNinjaBuild_NaCl(platform, rel_out_dir):
 
 
 def GypNinjaBuild_Breakpad(platform, rel_out_dir):
+  # TODO(binji): dump_syms doesn't currently build on Windows. See
+  # http://crbug.com/245456
+  if platform == 'win':
+    return
+
   gyp_py = os.path.join(SRC_DIR, 'build', 'gyp_chromium')
   out_dir = MakeNinjaRelPath(rel_out_dir)
   gyp_file = os.path.join(SRC_DIR, 'breakpad', 'breakpad.gyp')
-  GypNinjaBuild('ia32', gyp_py, gyp_file, 'dump_syms', out_dir)
+  build_list = ['dump_syms', 'minidump_dump', 'minidump_stackwalk']
+  GypNinjaBuild('ia32', gyp_py, gyp_file, build_list, out_dir)
 
 
 def GypNinjaBuild_PPAPI(arch, rel_out_dir):
@@ -554,6 +567,16 @@ def GypNinjaBuild_Pnacl(rel_out_dir, target_arch):
   targets = ['pnacl_irt_shim']
   GypNinjaBuild(target_arch, gyp_py, gyp_file, targets, out_dir, False)
 
+  gyp_py = os.path.join(NACL_DIR, 'build', 'gyp_nacl')
+  gyp_file = os.path.join(NACL_DIR, 'src', 'untrusted', 'minidump_generator',
+                          'minidump_generator.gyp')
+  targets = ['minidump_generator_lib']
+  GypNinjaBuild(target_arch, gyp_py, gyp_file, targets, out_dir, False)
+
+  gyp_file = os.path.join(NACL_DIR, 'src', 'untrusted', 'nacl', 'nacl.gyp')
+  targets = ['nacl_exception_lib']
+  GypNinjaBuild(target_arch, gyp_py, gyp_file, targets, out_dir, False)
+
 
 def GypNinjaBuild(arch, gyp_py_script, gyp_file, targets,
                   out_dir, force_arm_gcc=True):
@@ -593,8 +616,8 @@ def NinjaBuild(targets, out_dir):
 def BuildStepBuildToolchains(pepperdir, platform, toolchains):
   buildbot_common.BuildStep('SDK Items')
 
-  GypNinjaBuild_NaCl(platform, 'gypbuild')
-  GypNinjaBuild_Breakpad(platform, 'gypbuild')
+  GypNinjaBuild_NaCl(platform, GYPBUILD_DIR)
+  GypNinjaBuild_Breakpad(platform, GYPBUILD_DIR)
 
   tcname = platform + '_x86'
   newlibdir = os.path.join(pepperdir, 'toolchain', tcname + '_newlib')
@@ -602,10 +625,10 @@ def BuildStepBuildToolchains(pepperdir, platform, toolchains):
   pnacldir = os.path.join(pepperdir, 'toolchain', tcname + '_pnacl')
 
   if set(toolchains) & set(['glibc', 'newlib']):
-    GypNinjaBuild_PPAPI('ia32', 'gypbuild')
+    GypNinjaBuild_PPAPI('ia32', GYPBUILD_DIR)
 
   if 'arm' in toolchains:
-    GypNinjaBuild_PPAPI('arm', 'gypbuild-arm')
+    GypNinjaBuild_PPAPI('arm', GYPBUILD_DIR + '-arm')
 
   GypNinjaInstall(pepperdir, platform, toolchains)
 
@@ -624,6 +647,8 @@ def BuildStepBuildToolchains(pepperdir, platform, toolchains):
                        'arm')
 
   if 'pnacl' in toolchains:
+    # shell=True is needed on windows to enable searching of the PATH:
+    # http://bugs.python.org/issue8557
     shell = platform == 'win'
     buildbot_common.Run(
         GetSconsArgs(pnacldir, pepperdir, 'x86', '32'),
@@ -632,7 +657,7 @@ def BuildStepBuildToolchains(pepperdir, platform, toolchains):
 
     for arch in ('ia32', 'arm'):
       # Fill in the latest native pnacl shim library from the chrome build.
-      build_dir = 'gypbuild-pnacl-' + arch
+      build_dir = GYPBUILD_DIR + '-pnacl-' + arch
       GypNinjaBuild_Pnacl(build_dir, arch)
       pnacl_libdir_map = {'ia32': 'x86-64', 'arm': 'arm'}
       release_build_dir = os.path.join(OUT_DIR, build_dir, 'Release',
@@ -643,6 +668,16 @@ def BuildStepBuildToolchains(pepperdir, platform, toolchains):
           os.path.join(release_build_dir, 'libpnacl_irt_shim.a'),
           GetPNaClNativeLib(pnacldir, pnacl_libdir_map[arch]))
 
+      release_build_dir = os.path.join(OUT_DIR, build_dir, 'Release',
+                                       'gen', 'tc_pnacl_newlib', 'lib')
+      buildbot_common.CopyFile(
+          os.path.join(release_build_dir, 'libminidump_generator.a'),
+          GetPNaClNativeLib(pnacldir, pnacl_libdir_map[arch]))
+
+      buildbot_common.CopyFile(
+          os.path.join(release_build_dir, 'libnacl_exception.a'),
+          GetPNaClNativeLib(pnacldir, pnacl_libdir_map[arch]))
+
     InstallNaClHeaders(GetToolchainNaClInclude('pnacl', pnacldir, 'x86'),
                        'newlib')
 
@@ -741,9 +776,30 @@ def GenerateNotice(fileroot, output_filename='NOTICE', extra_files=None):
 
 def BuildStepVerifyFilelist(pepperdir, platform):
   buildbot_common.BuildStep('Verify SDK Files')
-  verify_filelist.Verify(platform, os.path.join(SCRIPT_DIR, 'sdk_files.list'),
-                         pepperdir)
-  print 'OK'
+  file_list_path = os.path.join(SCRIPT_DIR, 'sdk_files.list')
+  try:
+    verify_filelist.Verify(platform, file_list_path, pepperdir)
+    print 'OK'
+  except verify_filelist.ParseException, e:
+    buildbot_common.ErrorExit('Parsing sdk_files.list failed:\n\n%s' % e)
+  except verify_filelist.VerifyException, e:
+    file_list_rel = os.path.relpath(file_list_path)
+    verify_filelist_py = os.path.splitext(verify_filelist.__file__)[0] + '.py'
+    verify_filelist_py = os.path.relpath(verify_filelist_py)
+    pepperdir_rel = os.path.relpath(pepperdir)
+
+    msg = """\
+SDK verification failed:
+
+%s
+Add/remove files from %s to fix.
+
+Run:
+    ./%s %s %s
+to test.""" % (e, file_list_rel, verify_filelist_py, file_list_rel,
+               pepperdir_rel)
+    buildbot_common.ErrorExit(msg)
+
 
 
 def BuildStepTarBundle(pepper_ver, tarfile):
@@ -959,7 +1015,7 @@ def main(args):
   # Archive on non-trybots.
   if options.archive:
     BuildStepArchiveBundle('build', pepper_ver, clnumber, tarfile)
-    if platform == 'linux':
+    if options.build_ports and platform == 'linux':
       BuildStepArchiveBundle('naclports', pepper_ver, clnumber, ports_tarfile)
     BuildStepArchiveSDKTools()
 
diff --git a/native_client_sdk/src/build_tools/buildbot_common.py b/native_client_sdk/src/build_tools/buildbot_common.py
index 4de37f8d83..157cd0b856 100644
--- a/native_client_sdk/src/build_tools/buildbot_common.py
+++ b/native_client_sdk/src/build_tools/buildbot_common.py
@@ -14,6 +14,7 @@ from build_paths import SDK_SRC_DIR, NACL_DIR
 
 sys.path.append(os.path.join(SDK_SRC_DIR, 'tools'))
 import oshelpers
+import getos
 
 def IsSDKBuilder():
   """Returns True if this script is running on an SDK builder.
@@ -39,7 +40,7 @@ def IsSDKTrybot():
 
 def ErrorExit(msg):
   """Write and error to stderr, then exit with 1 signaling failure."""
-  sys.stderr.write(msg + '\n')
+  sys.stderr.write(str(msg) + '\n')
   sys.exit(1)
 
 
@@ -101,16 +102,19 @@ def Run(args, cwd=None, env=None, shell=False):
   so this should be avoided when not using platform dependent shell scripts."""
 
   # We need to modify the environment to build host on Windows.
-  if not env:
-    if sys.platform.startswith('cygwin') or sys.platform.startswith('win'):
-      env = GetWindowsEnvironment()
-    else:
-      env = os.environ
+  if not env and getos.GetPlatform() == 'win':
+    env = GetWindowsEnvironment()
 
   print 'Running: ' + ' '.join(args)
   sys.stdout.flush()
   sys.stderr.flush()
-  subprocess.check_call(args, cwd=cwd, env=env, shell=shell)
+  try:
+    subprocess.check_call(args, cwd=cwd, env=env, shell=shell)
+  except subprocess.CalledProcessError as e:
+    sys.stdout.flush()
+    sys.stderr.flush()
+    ErrorExit('buildbot_common: %s' % e)
+
   sys.stdout.flush()
   sys.stderr.flush()
 
@@ -159,12 +163,17 @@ def RemoveFile(dst):
 
 
 BOT_GSUTIL = '/b/build/scripts/slave/gsutil'
+# On Windows, the current working directory may be on a different drive than
+# gsutil.
+WIN_BOT_GSUTIL = 'E:' + BOT_GSUTIL
 LOCAL_GSUTIL = 'gsutil'
 
 
 def GetGsutil():
   if os.environ.get('BUILDBOT_BUILDERNAME') \
      and not os.environ.get('BUILDBOT_FAKE'):
+    if getos.GetPlatform() == 'win':
+      return WIN_BOT_GSUTIL
     return BOT_GSUTIL
   else:
     return LOCAL_GSUTIL
@@ -174,10 +183,14 @@ def Archive(filename, bucket_path, cwd=None, step_link=True):
   """Upload the given filename to Google Store."""
   full_dst = 'gs://%s/%s' % (bucket_path, filename)
 
-  subprocess.check_call(
-      '%s cp -a public-read %s %s' % (GetGsutil(), filename, full_dst),
-      shell=True,
-      cwd=cwd)
+  # Since GetGsutil() might just return 'gsutil' and expect it to be looked
+  # up in the PATH, we must pass shell=True on windows.
+  # Without shell=True the windows implementation of subprocess.call will not
+  # search the PATH for the executable: http://bugs.python.org/issue8557
+  shell = getos.GetPlatform() == 'win'
+
+  cmd = [GetGsutil(), 'cp', '-a', 'public-read', filename, full_dst]
+  Run(cmd, shell=shell, cwd=cwd)
   url = 'https://commondatastorage.googleapis.com/'\
         '%s/%s' % (bucket_path, filename)
   if step_link:
diff --git a/native_client_sdk/src/build_tools/buildbot_run.py b/native_client_sdk/src/build_tools/buildbot_run.py
index f5e4ba585d..c74308e724 100755
--- a/native_client_sdk/src/build_tools/buildbot_run.py
+++ b/native_client_sdk/src/build_tools/buildbot_run.py
@@ -14,9 +14,12 @@ run.
 
 import buildbot_common
 import os
+import subprocess
 import sys
+
 from buildbot_common import Run
-from build_paths import SDK_SRC_DIR, SCRIPT_DIR
+from build_paths import SRC_DIR, SDK_SRC_DIR, SCRIPT_DIR
+import getos
 
 
 def StepRunUnittests():
@@ -33,7 +36,25 @@ def StepRunUnittests():
 
 
 def StepBuildSDK(args):
-  Run([sys.executable, 'build_sdk.py'] + args, cwd=SCRIPT_DIR)
+  is_win = getos.GetPlatform() == 'win'
+
+  # Windows has a path length limit of 255 characters, after joining cwd with a
+  # relative path. Use subst before building to keep the path lengths short.
+  if is_win:
+    subst_drive = 'S:'
+    root_dir = os.path.dirname(SRC_DIR)
+    new_root_dir = subst_drive + '\\'
+    subprocess.check_call(['subst', subst_drive, root_dir])
+    new_script_dir = os.path.join(new_root_dir,
+                                  os.path.relpath(SCRIPT_DIR, root_dir))
+  else:
+    new_script_dir = SCRIPT_DIR
+
+  try:
+    Run([sys.executable, 'build_sdk.py'] + args, cwd=new_script_dir)
+  finally:
+    if is_win:
+      subprocess.check_call(['subst', '/D', subst_drive])
 
 
 def StepTestSDK():
diff --git a/native_client_sdk/src/build_tools/generate_make.py b/native_client_sdk/src/build_tools/generate_make.py
index 2c87f7c306..faad723a43 100644
--- a/native_client_sdk/src/build_tools/generate_make.py
+++ b/native_client_sdk/src/build_tools/generate_make.py
@@ -160,6 +160,9 @@ def FindAndCopyFiles(src_files, root, search_dirs, dst_dir):
         Trace('Skipping "%s", destination "%s" is newer.' % (
             src_file, dst_file))
         continue
+    dst_path = os.path.dirname(dst_file)
+    if not os.path.exists(dst_path):
+      buildbot_common.MakeDir(dst_path)
     buildbot_common.CopyFile(src_file, dst_file)
 
 
diff --git a/native_client_sdk/src/build_tools/sdk_files.list b/native_client_sdk/src/build_tools/sdk_files.list
index b1144262b9..67eafd07e2 100644
--- a/native_client_sdk/src/build_tools/sdk_files.list
+++ b/native_client_sdk/src/build_tools/sdk_files.list
@@ -114,6 +114,14 @@ examples/demo/drive/Makefile
 examples/demo/drive/manifest.json
 [win]examples/demo/make.bat
 examples/demo/Makefile
+[win]examples/demo/life/make.bat
+examples/demo/life/Makefile
+examples/demo/life/background.js
+examples/demo/life/common.js
+examples/demo/life/icon128.png
+examples/demo/life/index.html
+examples/demo/life/life.c
+examples/demo/life/manifest.json
 examples/demo/nacl_io/background.js
 examples/demo/nacl_io/common.js
 examples/demo/nacl_io/example.js
@@ -137,25 +145,34 @@ examples/demo/pi_generator/index.html
 examples/demo/pi_generator/Makefile
 examples/demo/pi_generator/manifest.json
 examples/demo/pi_generator/pi_generator.cc
+examples/demo/voronoi/background.js
+examples/demo/voronoi/common.js
+examples/demo/voronoi/example.js
+examples/demo/voronoi/icon128.png
+examples/demo/voronoi/index.html
+examples/demo/voronoi/Makefile
+[win]examples/demo/voronoi/make.bat
+examples/demo/voronoi/manifest.json
+examples/demo/voronoi/voronoi.cc
 examples/favicon.ico
+[win]examples/getting_started/hello_world/make.bat
+examples/getting_started/hello_world/Makefile
+examples/getting_started/hello_world/manifest.json
 examples/getting_started/hello_world/background.js
 examples/getting_started/hello_world/common.js
 examples/getting_started/hello_world/example.js
 examples/getting_started/hello_world/hello_world.c
 examples/getting_started/hello_world/icon128.png
 examples/getting_started/hello_world/index.html
-[win]examples/getting_started/hello_world/make.bat
-examples/getting_started/hello_world/Makefile
-examples/getting_started/hello_world/manifest.json
-examples/getting_started/hello_world_ppapi_main/background.js
-examples/getting_started/hello_world_ppapi_main/common.js
-examples/getting_started/hello_world_ppapi_main/example.js
-examples/getting_started/hello_world_ppapi_main/hello_world.c
-examples/getting_started/hello_world_ppapi_main/icon128.png
-examples/getting_started/hello_world_ppapi_main/index.html
-[win]examples/getting_started/hello_world_ppapi_main/make.bat
-examples/getting_started/hello_world_ppapi_main/Makefile
-examples/getting_started/hello_world_ppapi_main/manifest.json
+[win]examples/getting_started/simple_hello_world/make.bat
+examples/getting_started/simple_hello_world/Makefile
+examples/getting_started/simple_hello_world/manifest.json
+examples/getting_started/simple_hello_world/background.js
+examples/getting_started/simple_hello_world/common.js
+examples/getting_started/simple_hello_world/example.js
+examples/getting_started/simple_hello_world/hello_world.c
+examples/getting_started/simple_hello_world/icon128.png
+examples/getting_started/simple_hello_world/index.html
 [win]examples/getting_started/make.bat
 examples/getting_started/Makefile
 examples/httpd.cmd
@@ -215,6 +232,7 @@ include/json/reader.h
 include/json/value.h
 include/json/writer.h
 include/KHR/khrplatform.h
+include/nacl_io/error.h
 include/nacl_io/inode_pool.h
 include/nacl_io/kernel_handle.h
 include/nacl_io/kernel_intercept.h
@@ -230,6 +248,7 @@ include/nacl_io/mount_mem.h
 include/nacl_io/mount_node_dir.h
 include/nacl_io/mount_node.h
 include/nacl_io/mount_node_html5fs.h
+include/nacl_io/mount_node_http.h
 include/nacl_io/mount_node_mem.h
 include/nacl_io/mount_passthrough.h
 include/nacl_io/nacl_io.h
@@ -259,6 +278,7 @@ include/ppapi/c/dev/ppb_graphics_2d_dev.h
 include/ppapi/c/dev/ppb_ime_input_event_dev.h
 include/ppapi/c/dev/ppb_keyboard_input_event_dev.h
 include/ppapi/c/dev/ppb_memory_dev.h
+include/ppapi/c/dev/ppb_net_address_dev.h
 include/ppapi/c/dev/ppb_opengles2ext_dev.h
 include/ppapi/c/dev/ppb_printing_dev.h
 include/ppapi/c/dev/ppb_resource_array_dev.h
@@ -359,6 +379,7 @@ include/ppapi/cpp/dev/font_dev.h
 include/ppapi/cpp/dev/graphics_2d_dev.h
 include/ppapi/cpp/dev/ime_input_event_dev.h
 include/ppapi/cpp/dev/memory_dev.h
+include/ppapi/cpp/dev/net_address_dev.h
 include/ppapi/cpp/dev/printing_dev.h
 include/ppapi/cpp/dev/resource_array_dev.h
 include/ppapi/cpp/dev/scriptable_object_deprecated.h
@@ -443,12 +464,10 @@ include/ppapi/cpp/view.h
 include/ppapi/cpp/websocket.h
 include/ppapi/gles2/gl2ext_ppapi.h
 include/ppapi/lib/gl/gles2/gl2ext_ppapi.h
-include/ppapi_main/ppapi_event.h
-include/ppapi_main/ppapi_instance2d.h
-include/ppapi_main/ppapi_instance3d.h
-include/ppapi_main/ppapi_instance.h
-include/ppapi_main/ppapi_main.h
-include/ppapi_main/ppapi_queue.h
+include/ppapi_simple/ps.h
+include/ppapi_simple/ps_event.h
+include/ppapi_simple/ps_instance.h
+include/ppapi_simple/ps_main.h
 include/ppapi/utility/completion_callback_factory.h
 include/ppapi/utility/completion_callback_factory_thread_traits.h
 include/ppapi/utility/graphics/paint_aggregator.h
@@ -463,9 +482,11 @@ include/ppapi/utility/websocket/websocket_api.h
 [win]include/win/pthread.h
 [win]include/win/sched.h
 [win]include/win/semaphore.h
-include/utils/auto_lock.h
-include/utils/macros.h
-include/utils/ref_object.h
+include/sdk_util/auto_lock.h
+include/sdk_util/macros.h
+include/sdk_util/ref_object.h
+include/sdk_util/thread_safe_queue.h
+include/sdk_util/thread_pool.h
 lib/glibc_x86_32/Debug/libjsoncpp.a
 lib/glibc_x86_32/Debug/libjsoncpp.so
 lib/glibc_x86_32/Debug/libnacl_io.a
@@ -476,7 +497,10 @@ lib/glibc_x86_32/Debug/libppapi_cpp_private.a
 lib/glibc_x86_32/Debug/libppapi_cpp_private.so
 lib/glibc_x86_32/Debug/libppapi_gles2.a
 lib/glibc_x86_32/Debug/libppapi_gles2.so
-lib/glibc_x86_32/Debug/libppapi_main.a
+lib/glibc_x86_32/Debug/libppapi_simple.a
+lib/glibc_x86_32/Debug/libppapi_simple.so
+lib/glibc_x86_32/Debug/libsdk_util.a
+lib/glibc_x86_32/Debug/libsdk_util.so
 lib/glibc_x86_32/Release/libjsoncpp.a
 lib/glibc_x86_32/Release/libjsoncpp.so
 lib/glibc_x86_32/Release/libnacl_io.a
@@ -487,7 +511,10 @@ lib/glibc_x86_32/Release/libppapi_cpp_private.a
 lib/glibc_x86_32/Release/libppapi_cpp_private.so
 lib/glibc_x86_32/Release/libppapi_gles2.a
 lib/glibc_x86_32/Release/libppapi_gles2.so
-lib/glibc_x86_32/Release/libppapi_main.a
+lib/glibc_x86_32/Release/libppapi_simple.a
+lib/glibc_x86_32/Release/libppapi_simple.so
+lib/glibc_x86_32/Release/libsdk_util.a
+lib/glibc_x86_32/Release/libsdk_util.so
 lib/glibc_x86_64/Debug/libjsoncpp.a
 lib/glibc_x86_64/Debug/libjsoncpp.so
 lib/glibc_x86_64/Debug/libnacl_io.a
@@ -498,7 +525,10 @@ lib/glibc_x86_64/Debug/libppapi_cpp_private.a
 lib/glibc_x86_64/Debug/libppapi_cpp_private.so
 lib/glibc_x86_64/Debug/libppapi_gles2.a
 lib/glibc_x86_64/Debug/libppapi_gles2.so
-lib/glibc_x86_64/Debug/libppapi_main.a
+lib/glibc_x86_64/Debug/libppapi_simple.a
+lib/glibc_x86_64/Debug/libppapi_simple.so
+lib/glibc_x86_64/Debug/libsdk_util.a
+lib/glibc_x86_64/Debug/libsdk_util.so
 lib/glibc_x86_64/Release/libjsoncpp.a
 lib/glibc_x86_64/Release/libjsoncpp.so
 lib/glibc_x86_64/Release/libnacl_io.a
@@ -509,7 +539,10 @@ lib/glibc_x86_64/Release/libppapi_cpp_private.a
 lib/glibc_x86_64/Release/libppapi_cpp_private.so
 lib/glibc_x86_64/Release/libppapi_gles2.a
 lib/glibc_x86_64/Release/libppapi_gles2.so
-lib/glibc_x86_64/Release/libppapi_main.a
+lib/glibc_x86_64/Release/libppapi_simple.a
+lib/glibc_x86_64/Release/libppapi_simple.so
+lib/glibc_x86_64/Release/libsdk_util.a
+lib/glibc_x86_64/Release/libsdk_util.so
 [linux]lib/${PLATFORM}_host/Debug/libjsoncpp.a
 [linux]lib/${PLATFORM}_host/Debug/libppapi.a
 [linux]lib/${PLATFORM}_host/Debug/libppapi_cpp.a
@@ -534,60 +567,70 @@ lib/glibc_x86_64/Release/libppapi_main.a
 [win]lib/${PLATFORM}_x86_32_host/Release/ppapi_gles2.lib
 [win]lib/${PLATFORM}_x86_32_host/Release/ppapi.lib
 [win]lib/${PLATFORM}_x86_32_host/Release/pthread.lib
+[win]lib/${PLATFORM}_x86_32_host/Debug/sdk_util.lib
+[win]lib/${PLATFORM}_x86_32_host/Release/sdk_util.lib
 lib/newlib_arm/Debug/liberror_handling.a
 lib/newlib_arm/Debug/libjsoncpp.a
 lib/newlib_arm/Debug/libnacl_io.a
 lib/newlib_arm/Debug/libppapi_cpp.a
 lib/newlib_arm/Debug/libppapi_cpp_private.a
 lib/newlib_arm/Debug/libppapi_gles2.a
-lib/newlib_arm/Debug/libppapi_main.a
+lib/newlib_arm/Debug/libppapi_simple.a
+lib/newlib_arm/Debug/libsdk_util.a
 lib/newlib_arm/Release/liberror_handling.a
 lib/newlib_arm/Release/libjsoncpp.a
 lib/newlib_arm/Release/libnacl_io.a
 lib/newlib_arm/Release/libppapi_cpp.a
 lib/newlib_arm/Release/libppapi_cpp_private.a
 lib/newlib_arm/Release/libppapi_gles2.a
-lib/newlib_arm/Release/libppapi_main.a
+lib/newlib_arm/Release/libppapi_simple.a
+lib/newlib_arm/Release/libsdk_util.a
 lib/newlib_x86_32/Debug/liberror_handling.a
 lib/newlib_x86_32/Debug/libjsoncpp.a
 lib/newlib_x86_32/Debug/libnacl_io.a
 lib/newlib_x86_32/Debug/libppapi_cpp.a
 lib/newlib_x86_32/Debug/libppapi_cpp_private.a
 lib/newlib_x86_32/Debug/libppapi_gles2.a
-lib/newlib_x86_32/Debug/libppapi_main.a
+lib/newlib_x86_32/Debug/libppapi_simple.a
+lib/newlib_x86_32/Debug/libsdk_util.a
 lib/newlib_x86_32/Release/liberror_handling.a
 lib/newlib_x86_32/Release/libjsoncpp.a
 lib/newlib_x86_32/Release/libnacl_io.a
 lib/newlib_x86_32/Release/libppapi_cpp.a
 lib/newlib_x86_32/Release/libppapi_cpp_private.a
 lib/newlib_x86_32/Release/libppapi_gles2.a
-lib/newlib_x86_32/Release/libppapi_main.a
+lib/newlib_x86_32/Release/libppapi_simple.a
+lib/newlib_x86_32/Release/libsdk_util.a
 lib/newlib_x86_64/Debug/liberror_handling.a
 lib/newlib_x86_64/Debug/libjsoncpp.a
 lib/newlib_x86_64/Debug/libnacl_io.a
 lib/newlib_x86_64/Debug/libppapi_cpp.a
 lib/newlib_x86_64/Debug/libppapi_cpp_private.a
 lib/newlib_x86_64/Debug/libppapi_gles2.a
-lib/newlib_x86_64/Debug/libppapi_main.a
+lib/newlib_x86_64/Debug/libppapi_simple.a
+lib/newlib_x86_64/Debug/libsdk_util.a
 lib/newlib_x86_64/Release/liberror_handling.a
 lib/newlib_x86_64/Release/libjsoncpp.a
 lib/newlib_x86_64/Release/libnacl_io.a
 lib/newlib_x86_64/Release/libppapi_cpp.a
 lib/newlib_x86_64/Release/libppapi_cpp_private.a
 lib/newlib_x86_64/Release/libppapi_gles2.a
-lib/newlib_x86_64/Release/libppapi_main.a
+lib/newlib_x86_64/Release/libppapi_simple.a
+lib/newlib_x86_64/Release/libsdk_util.a
 lib/pnacl/Debug/libjsoncpp.a
 lib/pnacl/Debug/libnacl_io.a
 lib/pnacl/Debug/libppapi_cpp.a
 lib/pnacl/Debug/libppapi_cpp_private.a
 lib/pnacl/Debug/libppapi_gles2.a
-lib/pnacl/Debug/libppapi_main.a
+lib/pnacl/Debug/libppapi_simple.a
+lib/pnacl/Debug/libsdk_util.a
 lib/pnacl/Release/libjsoncpp.a
 lib/pnacl/Release/libnacl_io.a
 lib/pnacl/Release/libppapi_cpp.a
 lib/pnacl/Release/libppapi_cpp_private.a
 lib/pnacl/Release/libppapi_gles2.a
-lib/pnacl/Release/libppapi_main.a
+lib/pnacl/Release/libppapi_simple.a
+lib/pnacl/Release/libsdk_util.a
 LICENSE
 NOTICE
 README
@@ -626,6 +669,7 @@ src/nacl_io/mount_mem.cc
 src/nacl_io/mount_node.cc
 src/nacl_io/mount_node_dir.cc
 src/nacl_io/mount_node_html5fs.cc
+src/nacl_io/mount_node_http.cc
 src/nacl_io/mount_node_mem.cc
 src/nacl_io/mount_passthrough.cc
 src/nacl_io/nacl_io.cc
@@ -636,6 +680,7 @@ src/ppapi_cpp/array_output.cc
 src/ppapi_cpp/audio.cc
 src/ppapi_cpp/audio_config.cc
 src/ppapi_cpp/core.cc
+src/ppapi_cpp/directory_entry.cc
 src/ppapi_cpp/file_io.cc
 src/ppapi_cpp/file_ref.cc
 src/ppapi_cpp/file_system.cc
@@ -672,17 +717,17 @@ src/ppapi_gles2/gl2ext_ppapi.c
 src/ppapi_gles2/gles2.c
 [win]src/ppapi_gles2/make.bat
 src/ppapi_gles2/Makefile
-[win]src/ppapi_main/make.bat
-src/ppapi_main/Makefile
-src/ppapi_main/ppapi_instance2d.cc
-src/ppapi_main/ppapi_instance3d.cc
-src/ppapi_main/ppapi_instance.cc
-src/ppapi_main/ppapi_main.cc
-src/ppapi_main/ppapi_queue.cc
+[win]src/ppapi_simple/make.bat
+src/ppapi_simple/Makefile
+src/ppapi_simple/ps.cc
+src/ppapi_simple/ps_event.cc
+src/ppapi_simple/ps_instance.cc
+src/ppapi_simple/ps_main.cc
 src/ppapi_cpp_private/Makefile
 [win]src/ppapi_cpp_private/make.bat
 src/ppapi_cpp_private/file_io_private.cc
 src/ppapi_cpp_private/net_address_private.cc
+src/ppapi_cpp_private/pass_file_handle.cc
 src/ppapi_cpp_private/tcp_socket_private.cc
 src/ppapi_cpp_private/udp_socket_private.cc
 src/ppapi_cpp_private/ext_crx_file_system_private.cc
@@ -836,6 +881,9 @@ src/ppapi_cpp_private/x509_certificate_private.cc
 [win]src/ppapi/make.bat
 [win,linux]src/ppapi/Makefile
 [win,linux]src/ppapi/ppapi_externs.c
+src/sdk_util/Makefile
+[win]src/sdk_util/make.bat
+src/sdk_util/thread_pool.cc
 toolchain/${PLATFORM}_arm_newlib/arm-nacl/include/irt.h
 toolchain/${PLATFORM}_arm_newlib/arm-nacl/include/irt_ppapi.h
 toolchain/${PLATFORM}_arm_newlib/arm-nacl/include/nacl/dynamic_annotations.h
@@ -944,7 +992,8 @@ tools/compiler-wrapper.py
 tools/create_nmf.py
 tools/decode_dump.py
 [linux,mac]tools/dump_syms
-[win]tools/dump_syms.exe
+[linux,mac]tools/minidump_stackwalk
+[linux,mac]tools/minidump_dump
 tools/genhttpfs.py
 tools/getos.py
 tools/host_gcc.mk
@@ -957,17 +1006,10 @@ tools/nacl_gcc.mk
 [linux]tools/nacl_helper_bootstrap_x86_32
 [linux]tools/nacl_helper_bootstrap_x86_64
 tools/nacl_llvm.mk
-[linux,mac]tools/ncval_arm
-[win]tools/ncval_arm.exe
-[linux,mac]tools/ncval_x86_32
-[linux]tools/ncval_x86_64
-[win]tools/ncval_x86_32.exe
-[win]tools/ncval_x86_64.exe
+tools/ncval${EXE_EXT}
 tools/oshelpers.py
 tools/oshelpers.pyc
 tools/quote.py
 tools/run.py
-[linux,mac]tools/sel_ldr_x86_32
-[linux]tools/sel_ldr_x86_64
-[win]tools/sel_ldr_x86_32.exe
-[win]tools/sel_ldr_x86_64.exe
+tools/sel_ldr_x86_32${EXE_EXT}
+[linux,win]tools/sel_ldr_x86_64${EXE_EXT}
diff --git a/native_client_sdk/src/build_tools/sdk_tools/command/info.py b/native_client_sdk/src/build_tools/sdk_tools/command/info.py
index c412ddd281..6bf310fc6a 100644
--- a/native_client_sdk/src/build_tools/sdk_tools/command/info.py
+++ b/native_client_sdk/src/build_tools/sdk_tools/command/info.py
@@ -23,13 +23,11 @@ def Info(manifest, bundle_names):
     for key in sorted(bundle.iterkeys()):
       value = bundle[key]
       if key == manifest_util.ARCHIVES_KEY:
-        archive = bundle.GetHostOSArchive()
-        print '  Archive:'
-        if archive:
-          for archive_key in sorted(archive.iterkeys()):
-            print '    %s: %s' % (archive_key, archive[archive_key])
-        else:
-          print '    No archives for this host.'
+        for archive in bundle.GetArchives():
+          print '  Archive:'
+          if archive:
+            for archive_key in sorted(archive.iterkeys()):
+              print '    %s: %s' % (archive_key, archive[archive_key])
       elif key not in (manifest_util.ARCHIVES_KEY, manifest_util.NAME_KEY):
         print '  %s: %s' % (key, value)
     print
diff --git a/native_client_sdk/src/build_tools/tests/sdktools_commands_test.py b/native_client_sdk/src/build_tools/tests/sdktools_commands_test.py
index 2fae323c97..8abef29bfe 100755
--- a/native_client_sdk/src/build_tools/tests/sdktools_commands_test.py
+++ b/native_client_sdk/src/build_tools/tests/sdktools_commands_test.py
@@ -99,6 +99,18 @@ class TestCommands(SdkToolsTestCase):
     self.assertTrue('pepper_24' in output)
     self.assertFalse(re.search(r'[uU]nknown', output))
 
+  def testInfoMultipleArchives(self):
+    """The info command should display multiple archives."""
+    bundle = self._AddDummyBundle(self.manifest, 'pepper_26')
+    archive2 = self._MakeDummyArchive('pepper_26', tarname='pepper_26_more',
+                                      filename='dummy2.txt')
+    archive2.host_os = 'all'
+    bundle.AddArchive(archive2)
+    self._WriteManifest()
+    output = self._Run(['info', 'pepper_26'])
+    self.assertTrue('pepper_26' in output)
+    self.assertTrue('pepper_26_more' in output)
+
   def testListBasic(self):
     """The list command should display basic information about remote
     bundles."""
diff --git a/native_client_sdk/src/build_tools/verify_filelist.py b/native_client_sdk/src/build_tools/verify_filelist.py
index 7b75e91488..b97e4205ec 100755
--- a/native_client_sdk/src/build_tools/verify_filelist.py
+++ b/native_client_sdk/src/build_tools/verify_filelist.py
@@ -37,6 +37,7 @@ class Rules(object):
     self.exact_filenames = set()
     self.filename = filename
     self.platform = platform
+    self.exe_ext = '.exe' if platform == 'win' else ''
 
     if platform not in VALID_PLATFORMS:
       raise ParseException(self.filename, 1, 'Unknown platform %s' % platform)
@@ -67,6 +68,7 @@ class Rules(object):
       pattern = match.group(2)
 
     pattern = pattern.replace('${PLATFORM}', self.platform)
+    pattern = pattern.replace('${EXE_EXT}', self.exe_ext)
 
     if '*' in pattern:
       # glob pattern
diff --git a/native_client_sdk/src/examples/api/file_io/example.js b/native_client_sdk/src/examples/api/file_io/example.js
index e73f4b9462..1183c9cd43 100644
--- a/native_client_sdk/src/examples/api/file_io/example.js
+++ b/native_client_sdk/src/examples/api/file_io/example.js
@@ -19,6 +19,7 @@ function attachListeners() {
   document.getElementById('saveButton').addEventListener('click', saveFile);
   document.getElementById('loadButton').addEventListener('click', loadFile);
   document.getElementById('deleteButton').addEventListener('click', deleteFile);
+  document.getElementById('listButton').addEventListener('click', listDir);
 }
 
 function loadFile() {
@@ -55,6 +56,17 @@ function deleteFile() {
   }
 }
 
+function listDir() {
+  if (common.naclModule) {
+    var dirName = document.getElementById('dirName').value;
+
+    // Package a message using a simple protocol containing:
+    // instruction file_name_length file_name
+    var msg = "ls " + dirName.length + " " + dirName;
+    common.naclModule.postMessage(msg);
+  }
+}
+
 // Called by the common.js module.
 function handleMessage(message_event) {
   var messageParts = message_event.data.split("|", 3);
diff --git a/native_client_sdk/src/examples/api/file_io/file_io.cc b/native_client_sdk/src/examples/api/file_io/file_io.cc
index 9de72f8f6a..d8e27afd0f 100644
--- a/native_client_sdk/src/examples/api/file_io/file_io.cc
+++ b/native_client_sdk/src/examples/api/file_io/file_io.cc
@@ -11,6 +11,7 @@
 
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/ppb_file_io.h"
+#include "ppapi/cpp/directory_entry.h"
 #include "ppapi/cpp/file_io.h"
 #include "ppapi/cpp/file_ref.h"
 #include "ppapi/cpp/file_system.h"
@@ -39,6 +40,7 @@ namespace {
 const char* const kLoadPrefix = "ld";
 const char* const kSavePrefix = "sv";
 const char* const kDeletePrefix = "de";
+const char* const kListPrefix = "ls";
 }
 
 /// The Instance class.  One of these exists for each instance of your NaCl
@@ -133,6 +135,13 @@ class FileIoInstance : public pp::Instance {
           callback_factory_.NewCallback(&FileIoInstance::Delete, file_name));
       return;
     }
+
+    if (instruction.compare(kListPrefix) == 0) {
+      const std::string& dir_name = file_name;
+      file_thread_.message_loop().PostWork(
+          callback_factory_.NewCallback(&FileIoInstance::List, dir_name));
+      return;
+    }
   }
 
   void OpenFileSystem(int32_t /* result */) {
@@ -267,6 +276,35 @@ class FileIoInstance : public pp::Instance {
     ShowStatusMessage("File deleted");
   }
 
+  void List(int32_t /* result */, const std::string& dir_name) {
+    if (!file_system_ready_) {
+      ShowErrorMessage("File system is not open", PP_ERROR_FAILED);
+      return;
+    }
+    pp::FileRef ref(file_system_, dir_name.c_str());
+
+    // Pass ref along to keep it alive.
+    ref.ReadDirectoryEntries(callback_factory_.NewCallbackWithOutput(
+        &FileIoInstance::ListCallback, ref));
+  }
+
+  void ListCallback(int32_t result,
+                    const std::vector<pp::DirectoryEntry>& entries,
+                    pp::FileRef /* unused_ref */) {
+    if (result != PP_OK) {
+      ShowErrorMessage("List failed", result);
+      return;
+    }
+
+    std::string buffer = "File list:";
+    for (size_t i = 0; i < entries.size(); ++i) {
+      pp::Var name = entries[i].file_ref().GetName();
+      if (name.is_string())
+        buffer += " " + name.AsString();
+    }
+    ShowStatusMessage(buffer);
+  }
+
   /// Encapsulates our simple javascript communication protocol
   void ShowErrorMessage(const std::string& message, int32_t result) {
     std::stringstream ss;
diff --git a/native_client_sdk/src/examples/api/file_io/index.html b/native_client_sdk/src/examples/api/file_io/index.html
index 7625bd69c0..7c62ebdd9c 100644
--- a/native_client_sdk/src/examples/api/file_io/index.html
+++ b/native_client_sdk/src/examples/api/file_io/index.html
@@ -29,6 +29,10 @@
   <button id="loadButton" action="">Load</button>
   <button id="deleteButton" action="">Delete</button>
 
+  <br>Directory Name
+  <input type="text" id="dirName" action="" value="/">
+  <button id="listButton" action="">List</button>
+
   <!-- The NaCl plugin will be embedded inside the element with id "listener".
       See common.js.-->
   <div id="listener"></div>
diff --git a/native_client_sdk/src/examples/demo/life/example.dsc b/native_client_sdk/src/examples/demo/life/example.dsc
new file mode 100644
index 0000000000..215cfa8e8b
--- /dev/null
+++ b/native_client_sdk/src/examples/demo/life/example.dsc
@@ -0,0 +1,18 @@
+{
+  'TOOLS': ['newlib', 'glibc', 'pnacl'],
+  'TARGETS': [
+    {
+      'NAME' : 'life',
+      'TYPE' : 'main',
+      'SOURCES' : [
+        'life.c',
+      ],
+      'DEPS': ['ppapi_simple', 'nacl_io'],
+      'LIBS': ['ppapi_cpp', 'ppapi', 'pthread']
+    }
+  ],
+  'DEST': 'examples/demo',
+  'NAME': 'life',
+  'TITLE': "Conway's Life",
+  'GROUP': 'Demo'
+}
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/index.html b/native_client_sdk/src/examples/demo/life/index.html
index fa132dc7fd..626f532b5b 100644
--- a/native_client_sdk/src/examples/hello_world_instance3d/index.html
+++ b/native_client_sdk/src/examples/demo/life/index.html
@@ -11,17 +11,10 @@ found in the LICENSE file.
   <title>{{title}}</title>
   <script type="text/javascript" src="common.js"></script>
 </head>
-<body data-width="640" data-height="480" {{attrs}}>
+<body data-width="640" data-height="640" {{attrs}}>
   <h1>{{title}}</h1>
   <h2>Status: <code id="statusField">NO-STATUS</code></h2>
   <p>
-    The Hello World instance3d example is similar to the Hello World GLES 2.0
-    example, but uses the ppapi_main and nacl_io libraries to simplify the code:
-    <ul>
-      <li>URL loading is handled by a synchronous read from an HTTP mount.</li>
-      <li>Instance creation is hidden; instead the functions ppapi_main and
-          PPAPIRender are used.</li>
-    </ul>
   </p>
   <!-- The NaCl plugin will be embedded inside the element with id "listener".
       See common.js.-->
diff --git a/native_client_sdk/src/examples/demo/life/life.c b/native_client_sdk/src/examples/demo/life/life.c
new file mode 100644
index 0000000000..389d10e1fb
--- /dev/null
+++ b/native_client_sdk/src/examples/demo/life/life.c
@@ -0,0 +1,305 @@
+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ppapi/c/pp_resource.h"
+#include "ppapi/c/ppb_core.h"
+#include "ppapi/c/ppb_fullscreen.h"
+#include "ppapi/c/ppb_graphics_2d.h"
+#include "ppapi/c/ppb_image_data.h"
+#include "ppapi/c/ppb_input_event.h"
+#include "ppapi/c/ppb_instance.h"
+#include "ppapi/c/ppb_view.h"
+
+#include "ppapi_simple/ps_event.h"
+#include "ppapi_simple/ps_main.h"
+
+PPB_Core* g_pCore;
+PPB_Fullscreen* g_pFullscreen;
+PPB_Graphics2D* g_pGraphics2D;
+PPB_ImageData* g_pImageData;
+PPB_Instance* g_pInstance;
+PPB_View* g_pView;
+PPB_InputEvent* g_pInputEvent;
+PPB_KeyboardInputEvent* g_pKeyboardInput;
+PPB_MouseInputEvent* g_pMouseInput;
+PPB_TouchInputEvent* g_pTouchInput;
+
+struct {
+  PP_Resource ctx;
+  struct PP_Size size;
+  int bound;
+  uint8_t* cell_in;
+  uint8_t* cell_out;
+} g_Context;
+
+
+const unsigned int kInitialRandSeed = 0xC0DE533D;
+
+#define MakeRGBA(r, g, b, a)  \
+  (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
+
+
+/*
+ * Given a count of cells in a 3x3 grid where cells are worth 1 except for
+ * the center which is worth 9, this is a color representation of how
+ * "alive" that cell is making for a more interesting representation than
+ * a binary alive or dead.
+ */
+const uint32_t kNeighborColors[] = {
+    MakeRGBA(0x00, 0x00, 0x00, 0xff),
+    MakeRGBA(0x00, 0x40, 0x00, 0xff),
+    MakeRGBA(0x00, 0x60, 0x00, 0xff),
+    MakeRGBA(0x00, 0x80, 0x00, 0xff),
+    MakeRGBA(0x00, 0xA0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xC0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xE0, 0x00, 0xff),
+    MakeRGBA(0x00, 0x00, 0x00, 0xff),
+    MakeRGBA(0x00, 0x40, 0x00, 0xff),
+    MakeRGBA(0x00, 0x60, 0x00, 0xff),
+    MakeRGBA(0x00, 0x80, 0x00, 0xff),
+    MakeRGBA(0x00, 0xA0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xC0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xE0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+};
+
+/*
+ * These represent the new health value of a cell based on its neighboring
+ * values.  The health is binary: either alive or dead.
+ */
+const uint8_t kIsAlive[] = {
+      0, 0, 0, 1, 0, 0, 0, 0, 0,  /* Values if the center cell is dead. */
+      0, 0, 1, 1, 0, 0, 0, 0, 0   /* Values if the center cell is alive. */
+};
+
+void UpdateContext(uint32_t width, uint32_t height) {
+  if (width != g_Context.size.width || height != g_Context.size.height) {
+    size_t size = width * height;
+    size_t index;
+
+    free(g_Context.cell_in);
+    free(g_Context.cell_out);
+
+    /* Create a new context */
+    g_Context.cell_in = (uint8_t*) malloc(size);
+    g_Context.cell_out = (uint8_t*) malloc(size);
+
+    memset(g_Context.cell_out, 0, size);
+    for (index = 0; index < size; index++) {
+      g_Context.cell_in[index] = rand() & 1;
+    }
+  }
+
+  /* Recreate the graphics context on a view change */
+  g_pCore->ReleaseResource(g_Context.ctx);
+  g_Context.size.width = width;
+  g_Context.size.height = height;
+  g_Context.ctx =
+      g_pGraphics2D->Create(PSGetInstanceId(), &g_Context.size, PP_TRUE);
+  g_Context.bound =
+      g_pInstance->BindGraphics(PSGetInstanceId(), g_Context.ctx);
+}
+
+void DrawCell(int32_t x, int32_t y) {
+  int32_t width = g_Context.size.width;
+  int32_t height = g_Context.size.height;
+
+  if (!g_Context.cell_in) return;
+
+  if (x > 0 && x < width - 1 && y > 0 && y < height - 1) {
+    g_Context.cell_in[x - 1 + y * width] = 1;
+    g_Context.cell_in[x + 1 + y * width] = 1;
+    g_Context.cell_in[x + (y - 1) * width] = 1;
+    g_Context.cell_in[x + (y + 1) * width] = 1;
+  }
+}
+
+
+void ProcessEvent(PSEvent* event) {
+  switch(event->type) {
+    /* If the view updates, build a new Graphics 2D Context */
+    case PSE_INSTANCE_DIDCHANGEVIEW: {
+      struct PP_Rect rect;
+
+      g_pView->GetRect(event->as_resource, &rect);
+      UpdateContext(rect.size.width, rect.size.height);
+      break;
+    }
+
+    case PSE_INSTANCE_HANDLEINPUT: {
+      PP_InputEvent_Type type = g_pInputEvent->GetType(event->as_resource);
+      PP_InputEvent_Modifier modifiers =
+          g_pInputEvent->GetModifiers(event->as_resource);
+
+      switch(type) {
+        case PP_INPUTEVENT_TYPE_MOUSEDOWN: {
+          struct PP_Point location =
+              g_pMouseInput->GetPosition(event->as_resource);
+          DrawCell(location.x, location.y);
+          break;
+        }
+
+        case PP_INPUTEVENT_TYPE_MOUSEMOVE: {
+            struct PP_Point location =
+                g_pMouseInput->GetPosition(event->as_resource);
+
+            /* If the button is down, draw */
+            if (modifiers & PP_INPUTEVENT_MODIFIER_LEFTBUTTONDOWN) {
+              DrawCell(location.x, location.y);
+            }
+          break;
+        }
+
+        case PP_INPUTEVENT_TYPE_KEYDOWN: {
+          PP_Bool fullscreen = g_pFullscreen->IsFullscreen(PSGetInstanceId());
+          g_pFullscreen->SetFullscreen(PSGetInstanceId(),
+                                       fullscreen ? PP_FALSE : PP_TRUE);
+          break;
+        }
+        default:
+          break;
+      }
+      /* case PSE_INSTANCE_HANDLEINPUT */
+      break;
+    }
+
+    default:
+      break;
+  }
+}
+
+
+void Stir(uint32_t width, uint32_t height) {
+  int i;
+  if (g_Context.cell_in == NULL || g_Context.cell_out == NULL)
+    return;
+
+  for (i = 0; i < width; ++i) {
+    g_Context.cell_in[i] = rand() & 1;
+    g_Context.cell_in[i + (height - 1) * width] = rand() & 1;
+  }
+  for (i = 0; i < height; ++i) {
+    g_Context.cell_in[i * width] = rand() & 1;
+    g_Context.cell_in[i * width + (width - 1)] = rand() & 1;
+  }
+}
+
+void Render() {
+  struct PP_Size* psize = &g_Context.size;
+  PP_ImageDataFormat format = g_pImageData->GetNativeImageDataFormat();
+
+  /*
+   * Create a buffer to draw into.  Since we are waiting until the next flush
+   * chrome has an opportunity to cache this buffer see ppb_graphics_2d.h.
+   */
+  PP_Resource image =
+      g_pImageData->Create(PSGetInstanceId(), format, psize, PP_FALSE);
+  uint8_t* pixels = g_pImageData->Map(image);
+
+  struct PP_ImageDataDesc desc;
+  uint8_t* cell_temp;
+  uint32_t x, y;
+
+  /* If we somehow have not allocated these pointers yet, skip this frame. */
+  if (!g_Context.cell_in || !g_Context.cell_out) return;
+
+  /* Get the stride. */
+  g_pImageData->Describe(image, &desc);
+
+  /* Stir up the edges to prevent the simulation from reaching steady state. */
+  Stir(desc.size.width, desc.size.height);
+
+  /* Do neighbor summation; apply rules, output pixel color. */
+  for (y = 1; y < desc.size.height - 1; ++y) {
+    uint8_t *src0 = (g_Context.cell_in + (y - 1) * desc.size.width) + 1;
+    uint8_t *src1 = src0 + desc.size.width;
+    uint8_t *src2 = src1 + desc.size.width;
+    int count;
+    uint32_t color;
+    uint8_t *dst = (g_Context.cell_out + y * desc.size.width) + 1;
+    uint32_t *pixel_line =  (uint32_t*) (pixels + y * desc.stride);
+
+    for (x = 1; x < (desc.size.width - 1); ++x) {
+      /* Build sum, weight center by 9x. */
+      count = src0[-1] + src0[0] +     src0[1] +
+              src1[-1] + src1[0] * 9 + src1[1] +
+              src2[-1] + src2[0] +     src2[1];
+      color = kNeighborColors[count];
+
+      *pixel_line++ = color;
+      *dst++ = kIsAlive[count];
+      ++src0;
+      ++src1;
+      ++src2;
+    }
+  }
+
+  cell_temp = g_Context.cell_in;
+  g_Context.cell_in = g_Context.cell_out;
+  g_Context.cell_out = cell_temp;
+
+  /* Unmap the range, we no longer need it. */
+  g_pImageData->Unmap(image);
+
+  /* Replace the contexts, and block until it's on the screen. */
+  g_pGraphics2D->ReplaceContents(g_Context.ctx, image);
+  g_pGraphics2D->Flush(g_Context.ctx, PP_BlockUntilComplete());
+
+  /* Release the image data, we no longer need it. */
+  g_pCore->ReleaseResource(image);
+}
+
+/*
+ * Starting point for the module.  We do not use main since it would
+ * collide with main in libppapi_cpp.
+ */
+int example_main(int argc, const char *argv[]) {
+  fprintf(stdout,"Started main.\n");
+  g_pCore = (PPB_Core*)PSGetInterface(PPB_CORE_INTERFACE);
+  g_pFullscreen = (PPB_Fullscreen*)PSGetInterface(PPB_FULLSCREEN_INTERFACE);
+  g_pGraphics2D = (PPB_Graphics2D*)PSGetInterface(PPB_GRAPHICS_2D_INTERFACE);
+  g_pInstance = (PPB_Instance*)PSGetInterface(PPB_INSTANCE_INTERFACE);
+  g_pImageData = (PPB_ImageData*)PSGetInterface(PPB_IMAGEDATA_INTERFACE);
+  g_pView = (PPB_View*)PSGetInterface(PPB_VIEW_INTERFACE);
+
+  g_pInputEvent =
+      (PPB_InputEvent*) PSGetInterface(PPB_INPUT_EVENT_INTERFACE);
+  g_pKeyboardInput = (PPB_KeyboardInputEvent*)
+      PSGetInterface(PPB_KEYBOARD_INPUT_EVENT_INTERFACE);
+  g_pMouseInput =
+      (PPB_MouseInputEvent*) PSGetInterface(PPB_MOUSE_INPUT_EVENT_INTERFACE);
+  g_pTouchInput =
+      (PPB_TouchInputEvent*) PSGetInterface(PPB_TOUCH_INPUT_EVENT_INTERFACE);
+
+  PSEventSetFilter(PSE_ALL);
+  while (1) {
+    /* Process all waiting events without blocking */
+    PSEvent* event;
+    while ((event = PSEventTryAcquire()) != NULL) {
+      ProcessEvent(event);
+      PSEventRelease(event);
+    }
+
+    /* Render a frame, blocking until complete. */
+    if (g_Context.bound) {
+      Render();
+    }
+  }
+  return 0;
+}
+
+/*
+ * Register the function to call once the Instance Object is initialized.
+ * see: pappi_simple/ps_main.h
+ */
+PPAPI_SIMPLE_REGISTER_MAIN(example_main);
diff --git a/native_client_sdk/src/examples/demo/voronoi/example.dsc b/native_client_sdk/src/examples/demo/voronoi/example.dsc
new file mode 100644
index 0000000000..d9fabcebc9
--- /dev/null
+++ b/native_client_sdk/src/examples/demo/voronoi/example.dsc
@@ -0,0 +1,21 @@
+{
+  'TOOLS': ['newlib', 'glibc', 'pnacl'],
+  'TARGETS': [
+    {
+      'NAME' : 'voronoi',
+      'TYPE' : 'main',
+      'SOURCES' : [
+        'voronoi.cc'
+      ],
+
+      'LIBS': ['sdk_util', 'ppapi_cpp', 'ppapi', 'pthread']
+    }
+  ],
+  'DATA': [
+    'example.js',
+  ],
+  'DEST': 'examples/demo',
+  'NAME': 'voronoi',
+  'TITLE': 'Multi-Threaded Voronoi Demo',
+  'GROUP': 'Demo'
+}
diff --git a/native_client_sdk/src/examples/demo/voronoi/example.js b/native_client_sdk/src/examples/demo/voronoi/example.js
new file mode 100644
index 0000000000..aa02f38049
--- /dev/null
+++ b/native_client_sdk/src/examples/demo/voronoi/example.js
@@ -0,0 +1,59 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function moduleDidLoad() {
+}
+
+function postThreadFunc(numThreads) {
+  return function () {
+    common.naclModule.postMessage('threads: ' + numThreads);
+  }
+}
+
+// Add event listeners after the NaCl module has loaded.  These listeners will
+// forward messages to the NaCl module via postMessage()
+function attachListeners() {
+  document.getElementById('benchmark').addEventListener('click',
+    function() {
+      common.naclModule.postMessage('run benchmark');
+      common.updateStatus('BENCHMARKING... (please wait)');
+    });
+  document.getElementById('drawPoints').addEventListener('click',
+    function() {
+      var checked = document.getElementById('drawPoints').checked;
+      if (checked)
+        common.naclModule.postMessage('with points');
+      else
+        common.naclModule.postMessage('without points');
+    });
+  document.getElementById('drawInteriors').addEventListener('click',
+    function() {
+      var checked = document.getElementById('drawInteriors').checked;
+      if (checked)
+        common.naclModule.postMessage('with interiors');
+      else
+        common.naclModule.postMessage('without interiors');
+    });
+  var threads = [0, 1, 2, 4, 6, 8, 12, 16, 24, 32];
+  for (var i = 0; i < threads.length; i++) {
+    document.getElementById('radio'+i).addEventListener('click',
+        postThreadFunc(threads[i]));
+  }
+  document.getElementById('pointRange').addEventListener('change',
+    function() {
+      var value = document.getElementById('pointRange').value;
+      common.naclModule.postMessage('points: ' + value);
+      document.getElementById('pointCount').textContent = value + ' points';
+    });
+}
+
+// Handle a message coming from the NaCl module.
+// In the Voronoi example, the only message will be the benchmark result.
+function handleMessage(message_event) {
+  var x = (Math.round(message_event.data * 1000) / 1000).toFixed(3);
+  document.getElementById('result').textContent =
+    'Result: ' + x + ' seconds';
+  common.updateStatus('SUCCESS')
+}
+
diff --git a/native_client_sdk/src/examples/demo/voronoi/index.html b/native_client_sdk/src/examples/demo/voronoi/index.html
new file mode 100644
index 0000000000..7cbbd19deb
--- /dev/null
+++ b/native_client_sdk/src/examples/demo/voronoi/index.html
@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html>
+<!--
+Copyright (c) 2013 The Chromium Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+-->
+<head>
+  <meta http-equiv="Pragma" content="no-cache">
+  <meta http-equiv="Expires" content="-1">
+  <title>{{title}}</title>
+  <script type="text/javascript" src="common.js"></script>
+  <script type="text/javascript" src="example.js"></script>
+</head>
+<body {{attrs}} data-width="512" data-height="512">
+  <h1>{{title}}</h1>
+  <h2>Status: <code id="statusField">NO-STATUS</code></h2>
+  <div>
+    This demo renders the Voronoi diagram for a moving set of points using a
+    brute force technique.
+    <br>
+    Number of points:
+    <input type="range" id="pointRange"
+        min="1" max="1024" step="1" value="256" />
+    <label id="pointCount" >256 points</label>
+    <br>
+    Number of threads (0 is main thread):
+    <input type="radio" name="threadCount" id="radio0" value="0"
+        checked="checked">
+    <label for="radio0">0</label>
+    <input type="radio" name="threadCount" id="radio1" value="1">
+    <label for="radio1">1</label>
+    <input type="radio" name="threadCount" id="radio2" value="2">
+    <label for="radio2">2</label>
+    <input type="radio" name="threadCount" id="radio3" value="4">
+    <label for="radio3">4</label>
+    <input type="radio" name="threadCount" id="radio4" value="6">
+    <label for="radio4">6</label>
+    <input type="radio" name="threadCount" id="radio5" value="8">
+    <label for="radio5">8</label>
+    <input type="radio" name="threadCount" id="radio6" value="12">
+    <label for="radio6">12</label>
+    <input type="radio" name="threadCount" id="radio7" value="16">
+    <label for="radio7">16</label>
+    <input type="radio" name="threadCount" id="radio8" value="24">
+    <label for="radio8">24</label>
+    <input type="radio" name="threadCount" id="radio9" value="32">
+    <label for="radio9">32</label>
+    <br>
+    <input type="checkbox" id="drawPoints" checked="checked">
+    <label for="draw_points">Draw Points</label>
+    <input type="checkbox" id="drawInteriors" checked="checked">
+    <label for="draw_interiors">Draw Interiors</label>
+    <input type="submit" id="benchmark" value="Run Benchmark">
+    <label id="result" name="result"> </label>
+  </div>
+  <!-- The NaCl plugin will be embedded inside the element with id "listener".
+      See common.js.-->
+  <div id="listener"></div>
+</body>
+</html>
diff --git a/native_client_sdk/src/examples/demo/voronoi/voronoi.cc b/native_client_sdk/src/examples/demo/voronoi/voronoi.cc
new file mode 100644
index 0000000000..d4e1025181
--- /dev/null
+++ b/native_client_sdk/src/examples/demo/voronoi/voronoi.cc
@@ -0,0 +1,582 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <assert.h>
+#include <math.h>
+#include <ppapi/cpp/completion_callback.h>
+#include <ppapi/cpp/graphics_2d.h>
+#include <ppapi/cpp/image_data.h>
+#include <ppapi/cpp/input_event.h>
+#include <ppapi/cpp/instance.h>
+#include <ppapi/cpp/module.h>
+#include <ppapi/cpp/rect.h>
+#include <ppapi/cpp/size.h>
+#include <ppapi/cpp/var.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <string>
+
+#include "sdk_util/thread_pool.h"
+
+// Global properties used to setup Voronoi demo.
+namespace {
+const int kMinRectSize = 4;
+const int kStartRecurseSize = 32;  // must be power-of-two
+const float kHugeZ = 1.0e38f;
+const float kPI = M_PI;
+const float kTwoPI = kPI * 2.0f;
+const int kFramesToBenchmark = 100;
+const unsigned int kRandomStartSeed = 0xC0DE533D;
+const int kMaxPointCount = 1024;
+const int kStartPointCount = 256;
+
+unsigned int g_rand_state = kRandomStartSeed;
+
+// random number helper
+inline unsigned char rand255() {
+  return static_cast<unsigned char>(rand_r(&g_rand_state) & 255);
+}
+
+// random number helper
+inline float frand() {
+  return (static_cast<float>(rand_r(&g_rand_state)) /
+      static_cast<float>(RAND_MAX));
+}
+
+// reset random seed
+inline void rand_reset(unsigned int seed) {
+  g_rand_state = seed;
+}
+
+// returns true if input is power of two.
+inline bool is_pow2(int x) {
+  return (x & (x - 1)) == 0;
+}
+
+inline double getseconds() {
+  const double usec_to_sec = 0.000001;
+  timeval tv;
+  if (0 == gettimeofday(&tv, NULL))
+    return tv.tv_sec + tv.tv_usec * usec_to_sec;
+  return 0.0;
+}
+
+inline uint32_t MakeRGBA(uint32_t r, uint32_t g, uint32_t b, uint32_t a) {
+  return (((a) << 24) | ((r) << 16) | ((g) << 8) | (b));
+}
+}  // namespace
+
+// Vec2, simple 2D vector
+struct Vec2 {
+  float x, y;
+  Vec2() {}
+  Vec2(float px, float py) {
+    x = px;
+    y = py;
+  }
+  void Set(float px, float py) {
+    x = px;
+    y = py;
+  }
+};
+
+// The main object that runs Voronoi simulation.
+class Voronoi : public pp::Instance {
+ public:
+  explicit Voronoi(PP_Instance instance);
+  virtual ~Voronoi();
+
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    return true;
+  }
+
+  virtual void DidChangeView(const pp::Rect& position, const pp::Rect& clip);
+
+  // Catch events.
+  virtual bool HandleInputEvent(const pp::InputEvent& event);
+
+  // Catch messages posted from Javascript.
+  virtual void HandleMessage(const pp::Var& message);
+
+ private:
+  // Methods prefixed with 'w' are run on worker threads.
+  int wCell(float x, float y);
+  inline void wFillSpan(uint32_t *pixels, uint32_t color, int width);
+  void wRenderTile(int x, int y, int w, int h);
+  void wProcessTile(int x, int y, int w, int h);
+  void wSubdivide(int x, int y, int w, int h);
+  void wMakeRect(int region, int *x, int *y, int *w, int *h);
+  bool wTestRect(int *m, int x, int y, int w, int h);
+  void wFillRect(int x, int y, int w, int h, uint32_t color);
+  void wRenderRect(int x0, int y0, int x1, int y1);
+  void wRenderRegion(int region);
+  static void wRenderRegionEntry(int region, void *thiz);
+
+  // These methods are only called by the main thread.
+  void Reset();
+  void UpdateSim();
+  void RenderDot(float x, float y, uint32_t color1, uint32_t color2);
+  void SuperimposePositions();
+  void Render();
+  void Draw();
+  void StartBenchmark();
+  void EndBenchmark();
+
+  // Runs a tick of the simulations, updating all buffers.  Flushes the
+  // contents of |image_data_| to the 2D graphics context.
+  void Update();
+
+  // Create and initialize the 2D context used for drawing.
+  void CreateContext(const pp::Size& size);
+  // Destroy the 2D drawing context.
+  void DestroyContext();
+  // Push the pixels to the browser, then attempt to flush the 2D context.
+  void FlushPixelBuffer();
+  static void FlushCallback(void* data, int32_t result);
+
+
+  pp::Graphics2D* graphics_2d_context_;
+  pp::ImageData* image_data_;
+  Vec2 positions_[kMaxPointCount];
+  Vec2 screen_positions_[kMaxPointCount];
+  Vec2 velocities_[kMaxPointCount];
+  uint32_t colors_[kMaxPointCount];
+  float ang_;
+  int point_count_;
+  int num_threads_;
+  const int num_regions_;
+  bool draw_points_;
+  bool draw_interiors_;
+  ThreadPool* workers_;
+  int width_;
+  int height_;
+  uint32_t stride_in_pixels_;
+  uint32_t* pixel_buffer_;
+  int benchmark_frame_counter_;
+  bool benchmarking_;
+  double benchmark_start_time_;
+  double benchmark_end_time_;
+};
+
+
+
+void Voronoi::Reset() {
+  rand_reset(kRandomStartSeed);
+  ang_ = 0.0f;
+  for (int i = 0; i < kMaxPointCount; i++) {
+    // random initial start position
+    const float x = frand();
+    const float y = frand();
+    positions_[i].Set(x, y);
+    // random directional velocity ( -1..1, -1..1 )
+    const float speed = 0.0005f;
+    const float u = (frand() * 2.0f - 1.0f) * speed;
+    const float v = (frand() * 2.0f - 1.0f) * speed;
+    velocities_[i].Set(u, v);
+    // 'unique' color (well... unique enough for our purposes)
+    colors_[i] = MakeRGBA(rand255(), rand255(), rand255(), 255);
+  }
+}
+
+Voronoi::Voronoi(PP_Instance instance) : pp::Instance(instance),
+                                         graphics_2d_context_(NULL),
+                                         image_data_(NULL),
+                                         num_regions_(256) {
+  draw_points_ = true;
+  draw_interiors_ = true;
+  width_ = 0;
+  height_ = 0;
+  stride_in_pixels_ = 0;
+  pixel_buffer_ = NULL;
+  benchmark_frame_counter_ = 0;
+  benchmarking_ = false;
+
+  point_count_ = kStartPointCount;
+  Reset();
+
+  // By default, render from the dispatch thread.
+  num_threads_ = 0;
+  workers_ = new ThreadPool(num_threads_);
+
+  // Request PPAPI input events for mouse & keyboard.
+  RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE);
+  RequestInputEvents(PP_INPUTEVENT_CLASS_KEYBOARD);
+}
+
+Voronoi::~Voronoi() {
+  delete workers_;
+  DestroyContext();
+}
+
+// This is the core of the Voronoi calculation.  At a given point on the
+// screen, iterate through all voronoi positions and render them as 3D cones.
+// We're looking for the voronoi cell that generates the closest z value.
+// (not really cones - since it is all relative, we avoid doing the
+// expensive sqrt and test against z*z instead)
+// If multithreading, this function is only called by the worker threads.
+int Voronoi::wCell(float x, float y) {
+  int closest_cell = 0;
+  float zz = kHugeZ;
+  Vec2* pos = screen_positions_;
+  for (int i = 0; i < point_count_; ++i) {
+    // measured 5.18 cycles per iteration on a core2
+    float dx = x - pos[i].x;
+    float dy = y - pos[i].y;
+    float dd = (dx * dx + dy * dy);
+    if (dd < zz) {
+      zz = dd;
+      closest_cell = i;
+    }
+  }
+  return closest_cell;
+}
+
+// Given a region r, derive a non-overlapping rectangle for a thread to
+// work on.
+// If multithreading, this function is only called by the worker threads.
+void Voronoi::wMakeRect(int r, int* x, int* y, int* w, int* h) {
+  const int parts = 16;
+  assert(parts * parts == num_regions_);
+  *w = width_ / parts;
+  *h = height_ / parts;
+  *x = *w * (r % parts);
+  *y = *h * ((r / parts) % parts);
+}
+
+// Test 4 corners of a rectangle to see if they all belong to the same
+// voronoi cell.  Each test is expensive so bail asap.  Returns true
+// if all 4 corners match.
+// If multithreading, this function is only called by the worker threads.
+bool Voronoi::wTestRect(int* m, int x, int y, int w, int h) {
+  // each test is expensive, so exit ASAP
+  const int m0 = wCell(x, y);
+  const int m1 = wCell(x + w - 1, y);
+  if (m0 != m1) return false;
+  const int m2 = wCell(x, y + h - 1);
+  if (m0 != m2) return false;
+  const int m3 = wCell(x + w - 1, y + h - 1);
+  if (m0 != m3) return false;
+  // all 4 corners belong to the same cell
+  *m = m0;
+  return true;
+}
+
+// Quickly fill a span of pixels with a solid color.  Assumes
+// span width is divisible by 4.
+// If multithreading, this function is only called by the worker threads.
+inline void Voronoi::wFillSpan(uint32_t* pixels, uint32_t color, int width) {
+  if (!draw_interiors_) {
+    const uint32_t gray = MakeRGBA(128, 128, 128, 255);
+    color = gray;
+  }
+  for (int i = 0; i < width; i += 4) {
+    *pixels++ = color;
+    *pixels++ = color;
+    *pixels++ = color;
+    *pixels++ = color;
+  }
+}
+
+// Quickly fill a rectangle with a solid color.  Assumes
+// the width w parameter is evenly divisible by 4.
+// If multithreading, this function is only called by the worker threads.
+void Voronoi::wFillRect(int x, int y, int w, int h, uint32_t color) {
+  const uint32_t pitch = width_;
+  uint32_t* pixels = pixel_buffer_ + y * pitch + x;
+  for (int j = 0; j < h; j++) {
+    wFillSpan(pixels, color, w);
+    pixels += pitch;
+  }
+}
+
+// When recursive subdivision reaches a certain minimum without finding a
+// rectangle that has four matching corners belonging to the same voronoi
+// cell, this function will break the retangular 'tile' into smaller scanlines
+//  and look for opportunities to quick fill at the scanline level.  If the
+// scanline can't be quick filled, it will slow down even further and compute
+// voronoi membership per pixel.
+void Voronoi::wRenderTile(int x, int y, int w, int h) {
+  // rip through a tile
+  uint32_t* pixels = pixel_buffer_ + y * stride_in_pixels_ + x;
+  for (int j = 0; j < h; j++) {
+    // get start and end cell values
+    int ms = wCell(x + 0, y + j);
+    int me = wCell(x + w - 1, y + j);
+    // if the end points are the same, quick fill the span
+    if (ms == me) {
+      wFillSpan(pixels, colors_[ms], w);
+    } else {
+      // else compute each pixel in the span... this is the slow part!
+      uint32_t* p = pixels;
+      *p++ = colors_[ms];
+      for (int i = 1; i < (w - 1); i++) {
+        int m = wCell(x + i, y + j);
+        *p++ = colors_[m];
+      }
+      *p++ = colors_[me];
+    }
+    pixels += stride_in_pixels_;
+  }
+}
+
+// Take a rectangular region and do one of -
+//   If all four corners below to the same voronoi cell, stop recursion and
+// quick fill the rectangle.
+//   If the minimum rectangle size has been reached, break out of recursion
+// and process the rectangle.  This small rectangle is called a tile.
+//   Otherwise, keep recursively subdividing the rectangle into 4 equally
+// sized smaller rectangles.
+// Note: at the moment, these will always be squares, not rectangles.
+// If multithreading, this function is only called by the worker threads.
+void Voronoi::wSubdivide(int x, int y, int w, int h) {
+  int m;
+  // if all 4 corners are equal, quick fill interior
+  if (wTestRect(&m, x, y, w, h)) {
+    wFillRect(x, y, w, h, colors_[m]);
+  } else {
+    // did we reach the minimum rectangle size?
+    if ((w <= kMinRectSize) || (h <= kMinRectSize)) {
+      wRenderTile(x, y, w, h);
+    } else {
+      // else recurse into smaller rectangles
+      const int half_w = w / 2;
+      const int half_h = h / 2;
+      wSubdivide(x, y, half_w, half_h);
+      wSubdivide(x + half_w, y, half_w, half_h);
+      wSubdivide(x, y + half_h, half_w, half_h);
+      wSubdivide(x + half_w, y + half_h, half_w, half_h);
+    }
+  }
+}
+
+// This function cuts up the rectangle into power of 2 sized squares.  It
+// assumes the input rectangle w & h are evenly divisible by
+// kStartRecurseSize.
+// If multithreading, this function is only called by the worker threads.
+void Voronoi::wRenderRect(int x, int y, int w, int h) {
+  for (int iy = y; iy < (y + h); iy += kStartRecurseSize) {
+    for (int ix = x; ix < (x + w); ix += kStartRecurseSize) {
+      wSubdivide(ix, iy, kStartRecurseSize, kStartRecurseSize);
+    }
+  }
+}
+
+// If multithreading, this function is only called by the worker threads.
+void Voronoi::wRenderRegion(int region) {
+  // convert region # into x0, y0, x1, y1 rectangle
+  int x, y, w, h;
+  wMakeRect(region, &x, &y, &w, &h);
+  // render this rectangle
+  wRenderRect(x, y, w, h);
+}
+
+// Entry point for worker thread.  Can't pass a member function around, so we
+// have to do this little round-about.
+void Voronoi::wRenderRegionEntry(int region, void* thiz) {
+  static_cast<Voronoi*>(thiz)->wRenderRegion(region);
+}
+
+// Function Voronoi::UpdateSim()
+// Run a simple sim to move the voronoi positions.  This update loop
+// is run once per frame.  Called from the main thread only, and only
+// when the worker threads are idle.
+void Voronoi::UpdateSim() {
+  ang_ += 0.002f;
+  if (ang_ > kTwoPI) {
+    ang_ = ang_ - kTwoPI;
+  }
+  float z = cosf(ang_) * 3.0f;
+  // push the points around on the screen for animation
+  for (int j = 0; j < kMaxPointCount; j++) {
+    positions_[j].x += (velocities_[j].x) * z;
+    positions_[j].y += (velocities_[j].y) * z;
+    screen_positions_[j].x = positions_[j].x * width_;
+    screen_positions_[j].y = positions_[j].y * height_;
+  }
+}
+
+// Renders a small diamond shaped dot at x, y clipped against the window
+void Voronoi::RenderDot(float x, float y, uint32_t color1, uint32_t color2) {
+  const int ix = static_cast<int>(x);
+  const int iy = static_cast<int>(y);
+  // clip it against window
+  if (ix < 1) return;
+  if (ix >= (width_ - 1)) return;
+  if (iy < 1) return;
+  if (iy >= (height_ - 1)) return;
+  uint32_t* pixel = pixel_buffer_ + iy * stride_in_pixels_ + ix;
+  // render dot as a small diamond
+  *pixel = color1;
+  *(pixel - 1) = color2;
+  *(pixel + 1) = color2;
+  *(pixel - stride_in_pixels_) = color2;
+  *(pixel + stride_in_pixels_) = color2;
+}
+
+// Superimposes dots on the positions.
+void Voronoi::SuperimposePositions() {
+  const uint32_t white = MakeRGBA(255, 255, 255, 255);
+  const uint32_t gray = MakeRGBA(192, 192, 192, 255);
+  for (int i = 0; i < point_count_; i++) {
+    RenderDot(
+        screen_positions_[i].x, screen_positions_[i].y, white, gray);
+  }
+}
+
+// Renders the Voronoi diagram, dispatching the work to multiple threads.
+// Note: This Dispatch() is from the main PPAPI thread, so care must be taken
+// not to attempt PPAPI calls from the worker threads, since Dispatch() will
+// block here until all work is complete.  The worker threads are compute only
+// and do not make any PPAPI calls.
+void Voronoi::Render() {
+  workers_->Dispatch(num_regions_, wRenderRegionEntry, this);
+  if (draw_points_)
+    SuperimposePositions();
+}
+
+void Voronoi::DidChangeView(const pp::Rect& position, const pp::Rect& clip) {
+  if (position.size().width() == width_ &&
+      position.size().height() == height_)
+    return;  // Size didn't change, no need to update anything.
+
+  // Create a new device context with the new size.
+  DestroyContext();
+  CreateContext(position.size());
+  Update();
+}
+
+void Voronoi::StartBenchmark() {
+  Reset();
+  printf("Benchmark started...\n");
+  benchmark_frame_counter_ = kFramesToBenchmark;
+  benchmarking_ = true;
+  benchmark_start_time_ = getseconds();
+}
+
+void Voronoi::EndBenchmark() {
+  benchmark_end_time_ = getseconds();
+  printf("Benchmark ended... time: %2.5f\n",
+      benchmark_end_time_ - benchmark_start_time_);
+  benchmarking_ = false;
+  benchmark_frame_counter_ = 0;
+  pp::Var result(benchmark_end_time_ - benchmark_start_time_);
+  PostMessage(result);
+}
+
+// Handle input events from the user.
+bool Voronoi::HandleInputEvent(const pp::InputEvent& event) {
+  switch (event.GetType()) {
+    case PP_INPUTEVENT_TYPE_KEYDOWN: {
+      pp::KeyboardInputEvent key = pp::KeyboardInputEvent(event);
+      uint32_t key_code = key.GetKeyCode();
+      if (key_code == 84)  // 't' key
+        if (!benchmarking_)
+          StartBenchmark();
+      break;
+    }
+    default:
+      return false;
+  }
+  return true;
+}
+
+// Handle messages sent from Javascript.
+void Voronoi::HandleMessage(const pp::Var& message) {
+  if (message.is_string()) {
+    std::string message_string = message.AsString();
+    if (message_string == "run benchmark" && !benchmarking_)
+      StartBenchmark();
+    else if (message_string == "with points")
+      draw_points_ = true;
+    else if (message_string == "without points")
+      draw_points_ = false;
+    else if (message_string == "with interiors")
+      draw_interiors_ = true;
+    else if (message_string == "without interiors")
+      draw_interiors_ = false;
+    else if (strstr(message_string.c_str(), "points:")) {
+      int num_points = atoi(strstr(message_string.c_str(), " "));
+      point_count_ = std::min(kMaxPointCount, std::max(0, num_points));
+    } else if (strstr(message_string.c_str(), "threads:")) {
+      int thread_count = atoi(strstr(message_string.c_str(), " "));
+      delete workers_;
+      workers_ = new ThreadPool(thread_count);
+    }
+  }
+}
+
+void Voronoi::FlushCallback(void* thiz, int32_t result) {
+  static_cast<Voronoi*>(thiz)->Update();
+}
+
+// Update the 2d region and flush to make it visible on the page.
+void Voronoi::FlushPixelBuffer() {
+  graphics_2d_context_->PaintImageData(*image_data_, pp::Point(0, 0));
+  graphics_2d_context_->Flush(pp::CompletionCallback(&FlushCallback, this));
+}
+
+void Voronoi::Update() {
+  // Don't call FlushPixelBuffer() when benchmarking - vsync is enabled by
+  // default, and will throttle the benchmark results.
+  do {
+    UpdateSim();
+    Render();
+    if (!benchmarking_) break;
+    --benchmark_frame_counter_;
+  } while (benchmark_frame_counter_ > 0);
+  if (benchmarking_)
+    EndBenchmark();
+  FlushPixelBuffer();
+}
+
+void Voronoi::CreateContext(const pp::Size& size) {
+  graphics_2d_context_ = new pp::Graphics2D(this, size, false);
+  if (!BindGraphics(*graphics_2d_context_))
+    printf("Couldn't bind the device context\n");
+  image_data_ = new pp::ImageData(this,
+                                  PP_IMAGEDATAFORMAT_BGRA_PREMUL,
+                                  size,
+                                  false);
+  width_ = image_data_->size().width();
+  height_ = image_data_->size().height();
+  // This demo requires power of two width & height buffers.
+  assert(is_pow2(width_) && is_pow2(height_));
+  stride_in_pixels_ = static_cast<uint32_t>(image_data_->stride() / 4);
+  pixel_buffer_ = static_cast<uint32_t*>(image_data_->data());
+}
+
+void Voronoi::DestroyContext() {
+  delete graphics_2d_context_;
+  delete image_data_;
+  graphics_2d_context_ = NULL;
+  image_data_ = NULL;
+  width_ = 0;
+  height_ = 0;
+  stride_in_pixels_ = 0;
+  pixel_buffer_ = NULL;
+}
+
+class VoronoiModule : public pp::Module {
+ public:
+  VoronoiModule() : pp::Module() {}
+  virtual ~VoronoiModule() {}
+
+  // Create and return a Voronoi instance.
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new Voronoi(instance);
+  }
+};
+
+namespace pp {
+Module* CreateModule() {
+  return new VoronoiModule();
+}
+}  // namespace pp
+
diff --git a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/example.dsc b/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/example.dsc
deleted file mode 100644
index 19a2b4173a..0000000000
--- a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/example.dsc
+++ /dev/null
@@ -1,18 +0,0 @@
-{
-  'TOOLS': ['newlib', 'glibc', 'pnacl'],
-  'TARGETS': [
-    {
-      'NAME': 'hello_world_stdio',
-      'TYPE': 'main',
-      'SOURCES': ['hello_world.c'],
-      'LIBS': ['ppapi_main', 'nacl_io', 'ppapi_cpp', 'ppapi', 'pthread']
-    }
-  ],
-  'DATA': [
-    'example.js',
-  ],
-  'DEST': 'examples/getting_started',
-  'NAME': 'hello_world_ppapi_main',
-  'TITLE': 'Hello World (libppapi_main)',
-  'GROUP': 'Getting Started'
-}
diff --git a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/hello_world.c b/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/hello_world.c
deleted file mode 100644
index 1d3d6f10ff..0000000000
--- a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/hello_world.c
+++ /dev/null
@@ -1,50 +0,0 @@
-/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include <stdio.h>
-#include <string.h>
-
-#include "ppapi/c/ppb_var.h"
-#include "ppapi/c/ppb_messaging.h"
-#include "ppapi/c/ppb_console.h"
-
-#include "ppapi_main/ppapi_main.h"
-
-// The default arguments to PPAPI_MAIN maps:
-//   STDIN -> /dev/stdin
-//   STDOUT -> /dev/stdout
-//   STDERR -> /dev/console3
-// We use our own args here so that stdout sends messages to JavaScript via
-// PostMessage (/dev/tty).
-PPAPI_MAIN_WITH_ARGS("pm_stdout", "/dev/tty", NULL, NULL)
-
-//
-// The "main" entry point called by PPAPIInstance once initialization
-// takes place.  This is called off the main thread, which is hidden
-// from the developer, making it safe to use blocking calls.
-// The arguments are provided as:
-//   argv[0] = "NEXE"
-//   argv[1] = "--<KEY>"
-//   argv[2] = "<VALUE>"
-// Where the embed tag for this module uses KEY=VALUE
-//
-int ppapi_main(int argc, const char* argv[]) {
-  int index = 1;
-
-  // Use PostMessage to send "Hello World" to JavaScript.
-  printf("Hello World STDOUT.\n");
-
-  // Use PPAPI Console interface to send "Hello World" to the
-  // JavaScript Console.
-  fprintf(stderr, "Hello World STDERR.\n");
-
-  // Print the arguments we received from the web page
-  printf("NAME: %s\n", argv[0]);
-  while (index + 2 < argc) {
-    printf("  ARGS: %s=%s\n", argv[index + 0], argv[index + 1]);
-    index += 2;
-  }
-  return 0;
-}
diff --git a/native_client_sdk/src/examples/getting_started/simple_hello_world/example.dsc b/native_client_sdk/src/examples/getting_started/simple_hello_world/example.dsc
new file mode 100644
index 0000000000..de8c6a35f7
--- /dev/null
+++ b/native_client_sdk/src/examples/getting_started/simple_hello_world/example.dsc
@@ -0,0 +1,19 @@
+{
+  'TOOLS': ['newlib', 'glibc', 'pnacl'],
+  'TARGETS': [
+    {
+      'NAME' : 'simple_hello_world',
+      'TYPE' : 'main',
+      'SOURCES' : ['hello_world.c'],
+      'LIBS': ['ppapi_simple', 'nacl_io', 'ppapi_cpp', 'ppapi', 'pthread']
+    }
+  ],
+  'DATA': [
+    'example.js',
+  ],
+  'DEST': 'examples/getting_started',
+  'NAME': 'simple_hello_world',
+  'TITLE': 'Hello World (ppapi_simple)',
+  'GROUP': 'Getting Started'
+}
+
diff --git a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/example.js b/native_client_sdk/src/examples/getting_started/simple_hello_world/example.js
index 7f269215fe..7f269215fe 100644
--- a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/example.js
+++ b/native_client_sdk/src/examples/getting_started/simple_hello_world/example.js
diff --git a/native_client_sdk/src/examples/getting_started/simple_hello_world/hello_world.c b/native_client_sdk/src/examples/getting_started/simple_hello_world/hello_world.c
new file mode 100644
index 0000000000..082c62d4ea
--- /dev/null
+++ b/native_client_sdk/src/examples/getting_started/simple_hello_world/hello_world.c
@@ -0,0 +1,24 @@
+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "ppapi_simple/ps_main.h"
+
+int example_main(int argc, const char* argv[]) {
+  /* Use ppb_messaging to send "Hello World" to JavaScript. */
+  printf("Hello World STDOUT.\n");
+
+  /* Use ppb_console send "Hello World" to the JavaScript Console. */
+  fprintf(stderr, "Hello World STDERR.\n");
+  return 0;
+}
+
+/*
+ * Register the function to call once the Instance Object is initialized.
+ * see: pappi_simple/ps_main.h
+ */
+PPAPI_SIMPLE_REGISTER_MAIN(example_main)
diff --git a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/index.html b/native_client_sdk/src/examples/getting_started/simple_hello_world/index.html
index c6a4aa1ef4..c6a4aa1ef4 100644
--- a/native_client_sdk/src/examples/getting_started/hello_world_ppapi_main/index.html
+++ b/native_client_sdk/src/examples/getting_started/simple_hello_world/index.html
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/example.dsc b/native_client_sdk/src/examples/hello_world_instance3d/example.dsc
deleted file mode 100644
index 8dda62375e..0000000000
--- a/native_client_sdk/src/examples/hello_world_instance3d/example.dsc
+++ /dev/null
@@ -1,27 +0,0 @@
-{
-  'DISABLE': True,
-  'TOOLS': ['newlib', 'glibc', 'pnacl'],
-  'TARGETS': [
-    {
-      'NAME' : 'hello_world_instance3d',
-      'TYPE' : 'main',
-      'SOURCES' : ['hello_world.cc', 'matrix.cc', 'matrix.h'],
-      'CXXFLAGS': [
-        '-I../../src',
-        '-I../../src/ppapi/lib/gl'
-      ],
-      'DEPS': ['ppapi_main', 'nacl_io'],
-      'LIBS': ['ppapi_gles2', 'ppapi_cpp', 'ppapi',
-               'pthread']
-    }
-  ],
-  'DATA': [
-    'fragment_shader_es2.frag',
-    'hello.raw',
-    'vertex_shader_es2.vert'
-  ],
-  'DEST': 'examples',
-  'NAME': 'hello_world_instance3d',
-  'TITLE': 'Hello World GLES 2.0 using ppapi_instance3d',
-  'GROUP': 'API'
-}
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/fragment_shader_es2.frag b/native_client_sdk/src/examples/hello_world_instance3d/fragment_shader_es2.frag
deleted file mode 100644
index 247c559f8c..0000000000
--- a/native_client_sdk/src/examples/hello_world_instance3d/fragment_shader_es2.frag
+++ /dev/null
@@ -1,8 +0,0 @@
-precision mediump float; 
-varying vec3 v_color;
-varying vec2 v_texCoord;
-uniform sampler2D s_texture; 
-void main() 
-{ 
-	gl_FragColor = texture2D( s_texture, vec2(v_texCoord.x,1.0 - v_texCoord.y) ) + vec4(v_color.x,v_color.y,v_color.z,1);
-}
\ No newline at end of file
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/hello.raw b/native_client_sdk/src/examples/hello_world_instance3d/hello.raw
deleted file mode 100644
index 3320575072..0000000000
--- a/native_client_sdk/src/examples/hello_world_instance3d/hello.raw
+++ /dev/null
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/hello_world.cc b/native_client_sdk/src/examples/hello_world_instance3d/hello_world.cc
deleted file mode 100644
index 26515b7249..0000000000
--- a/native_client_sdk/src/examples/hello_world_instance3d/hello_world.cc
+++ /dev/null
@@ -1,325 +0,0 @@
-/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-/** @file hello_world_gles.cc
- * This example demonstrates loading and running a simple 3D openGL ES 2.0
- * application.
- */
-
-//---------------------------------------------------------------------------
-// The spinning Cube
-//---------------------------------------------------------------------------
-
-#define _USE_MATH_DEFINES 1
-#include <fcntl.h>
-#include <limits.h>
-#include <math.h>
-#include <stdarg.h>
-#include <stddef.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#include "nacl_io/nacl_io.h"
-
-#include "ppapi/c/pp_completion_callback.h"
-#include "ppapi/c/pp_errors.h"
-#include "ppapi/c/pp_instance.h"
-#include "ppapi/c/pp_module.h"
-#include "ppapi/c/pp_stdint.h"
-#include "ppapi/c/pp_var.h"
-#include "ppapi/c/ppb.h"
-#include "ppapi/c/ppb_opengles2.h"
-#include "ppapi/c/ppb_var.h"
-#include "ppapi/c/ppp.h"
-#include "ppapi/c/ppp_graphics_3d.h"
-#include "ppapi/c/ppp_instance.h"
-
-#include "ppapi/lib/gl/gles2/gl2ext_ppapi.h"
-
-#include "ppapi_main/ppapi_event.h"
-#include "ppapi_main/ppapi_instance3d.h"
-#include "ppapi_main/ppapi_main.h"
-
-#include <GLES2/gl2.h>
-#include "matrix.h"
-
-GLuint g_positionLoc;
-GLuint g_texCoordLoc;
-GLuint g_colorLoc;
-GLuint g_MVPLoc;
-GLuint g_vboID;
-GLuint g_ibID;
-GLubyte g_Indices[36];
-
-GLuint g_programObj;
-GLuint g_vertexShader;
-GLuint g_fragmentShader;
-
-GLuint g_textureLoc = 0;
-GLuint g_textureID = 0;
-
-float g_fSpinX = 0.0f;
-float g_fSpinY = 0.0f;
-
-//----------------------------------------------------------------------------
-// Rendering Assets
-//----------------------------------------------------------------------------
-struct Vertex {
-  float tu, tv;
-  float color[3];
-  float loc[3];
-};
-
-Vertex* g_quadVertices = NULL;
-const char* g_TextureData = NULL;
-const char* g_VShaderData = NULL;
-const char* g_FShaderData = NULL;
-
-bool g_Loaded = false;
-bool g_Ready = false;
-
-float g_xSpin = 2.0f;
-float g_ySpin = 0.5f;
-
-GLuint compileShader(GLenum type, const char* data) {
-  const char* shaderStrings[1];
-  shaderStrings[0] = data;
-
-  GLuint shader = glCreateShader(type);
-  glShaderSource(shader, 1, shaderStrings, NULL);
-  glCompileShader(shader);
-  return shader;
-}
-
-void InitProgram(void) {
-  g_vertexShader = compileShader(GL_VERTEX_SHADER, g_VShaderData);
-  g_fragmentShader = compileShader(GL_FRAGMENT_SHADER, g_FShaderData);
-
-  g_programObj = glCreateProgram();
-  glAttachShader(g_programObj, g_vertexShader);
-  glAttachShader(g_programObj, g_fragmentShader);
-  glLinkProgram(g_programObj);
-
-  glGenBuffers(1, &g_vboID);
-  glBindBuffer(GL_ARRAY_BUFFER, g_vboID);
-  glBufferData(GL_ARRAY_BUFFER,
-               24 * sizeof(Vertex),
-               (void*)&g_quadVertices[0],
-               GL_STATIC_DRAW);
-
-  glGenBuffers(1, &g_ibID);
-  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ibID);
-  glBufferData(GL_ELEMENT_ARRAY_BUFFER,
-               36 * sizeof(char),
-               (void*)&g_Indices[0],
-               GL_STATIC_DRAW);
-
-  //
-  // Create a texture to test out our fragment shader...
-  //
-  glGenTextures(1, &g_textureID);
-  glBindTexture(GL_TEXTURE_2D, g_textureID);
-  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 128, 128, 0, GL_RGB, GL_UNSIGNED_BYTE,
-               g_TextureData);
-
-  //
-  // Locate some parameters by name so we can set them later...
-  //
-  g_textureLoc = glGetUniformLocation(g_programObj, "arrowTexture");
-  g_positionLoc = glGetAttribLocation(g_programObj, "a_position");
-  g_texCoordLoc = glGetAttribLocation(g_programObj, "a_texCoord");
-  g_colorLoc = glGetAttribLocation(g_programObj, "a_color");
-  g_MVPLoc = glGetUniformLocation(g_programObj, "a_MVP");
-  printf("Program initialized.\n");
-}
-
-void BuildQuad(Vertex* verts, int axis[3], float depth, float color[3]) {
-  static float X[4] = { -1.0f, 1.0f, 1.0f, -1.0f };
-  static float Y[4] = { -1.0f, -1.0f, 1.0f, 1.0f };
-
-  for (int i = 0; i < 4; i++) {
-    verts[i].tu = (1.0 - X[i]) / 2.0f;
-    verts[i].tv = (Y[i] + 1.0f) / -2.0f * depth;
-    verts[i].loc[axis[0]] = X[i] * depth;
-    verts[i].loc[axis[1]] = Y[i] * depth;
-    verts[i].loc[axis[2]] = depth;
-    for (int j = 0; j < 3; j++)
-      verts[i].color[j] = color[j] * (Y[i] + 1.0f) / 2.0f;
-  }
-}
-
-Vertex* BuildCube() {
-  Vertex* verts = new Vertex[24];
-  for (int i = 0; i < 3; i++) {
-    int Faxis[3];
-    int Baxis[3];
-    float Fcolor[3];
-    float Bcolor[3];
-    for (int j = 0; j < 3; j++) {
-      Faxis[j] = (j + i) % 3;
-      Baxis[j] = (j + i) % 3;
-    }
-    memset(Fcolor, 0, sizeof(float) * 3);
-    memset(Bcolor, 0, sizeof(float) * 3);
-    Fcolor[i] = 0.5f;
-    Bcolor[i] = 1.0f;
-    BuildQuad(&verts[0 + i * 4], Faxis, 1.0f, Fcolor);
-    BuildQuad(&verts[12 + i * 4], Baxis, -1.0f, Bcolor);
-  }
-
-  for (int i = 0; i < 6; i++) {
-    g_Indices[i * 6 + 0] = 2 + i * 4;
-    g_Indices[i * 6 + 1] = 1 + i * 4;
-    g_Indices[i * 6 + 2] = 0 + i * 4;
-    g_Indices[i * 6 + 3] = 3 + i * 4;
-    g_Indices[i * 6 + 4] = 2 + i * 4;
-    g_Indices[i * 6 + 5] = 0 + i * 4;
-  }
-  return verts;
-}
-
-static float clamp(float val, float min, float max) {
-  if (val < min)
-    return min;
-  if (val > max)
-    return max;
-  return val;
-}
-
-void ProcessEvent(PPAPIEvent* event) {
-  if (event->event_type == PP_INPUTEVENT_TYPE_MOUSEMOVE) {
-    PPAPIMouseEvent* mouse = (PPAPIMouseEvent*)event;
-    g_ySpin = clamp((float) mouse->delta.x / 2, -4.0, 4.0);
-    g_xSpin = clamp((float) mouse->delta.y / 2, -4.0, 4.0);
-  }
-  if (event->event_type == PP_INPUTEVENT_TYPE_KEYUP) {
-    PPAPIKeyEvent* key = (PPAPIKeyEvent*)event;
-    if (key->key_code == 13) {
-      PPAPIInstance3D::GetInstance3D()->ToggleFullscreen();
-    }
-  }
-}
-
-void PPAPIRender(PP_Resource ctx, uint32_t width, uint32_t height) {
-  if (!g_Ready) {
-    if (g_Loaded) {
-      InitProgram();
-      g_Ready = true;
-    } else {
-      return;
-    }
-  }
-
-  PPAPIEvent* event;
-  while (PPAPIEvent* event = PPAPI_AcquireEvent()) {
-    ProcessEvent(event);
-    PPAPI_ReleaseEvent(event);
-  }
-
-  static float xRot = 0.0;
-  static float yRot = 0.0;
-
-  xRot -= g_xSpin;
-  yRot -= g_ySpin;
-
-  if (xRot >= 360.0f)
-    xRot = 0.0;
-  if (xRot <= -360.0f)
-    xRot = 0.0;
-
-  if (yRot >= 360.0f)
-    yRot = 0.0;
-  if (yRot <= -360.0f)
-    yRot = 0.0;
-
-  glClearColor(0.5, 0.5, 0.5, 1);
-  glClearDepthf(1.0);
-  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-  glEnable(GL_DEPTH_TEST);
-
-  //set what program to use
-  glUseProgram(g_programObj);
-  glActiveTexture(GL_TEXTURE0);
-  glBindTexture(GL_TEXTURE_2D, g_textureID);
-  glUniform1i(g_textureLoc, 0);
-
-  //create our perspective matrix
-  float mpv[16];
-  float trs[16];
-  float rot[16];
-
-  identity_matrix(mpv);
-  glhPerspectivef2(&mpv[0], 45.0f, (float)(width) / (float) height, 1, 10);
-
-  translate_matrix(0, 0, -4.0, trs);
-  rotate_matrix(xRot, yRot, 0.0f, rot);
-  multiply_matrix(trs, rot, trs);
-  multiply_matrix(mpv, trs, mpv);
-  glUniformMatrix4fv(g_MVPLoc, 1, GL_FALSE, (GLfloat*)mpv);
-
-  //define the attributes of the vertex
-  glBindBuffer(GL_ARRAY_BUFFER, g_vboID);
-  glVertexAttribPointer(g_positionLoc,
-                        3,
-                        GL_FLOAT,
-                        GL_FALSE,
-                        sizeof(Vertex),
-                        (void*)offsetof(Vertex, loc));
-  glEnableVertexAttribArray(g_positionLoc);
-  glVertexAttribPointer(g_texCoordLoc,
-                        2,
-                        GL_FLOAT,
-                        GL_FALSE,
-                        sizeof(Vertex),
-                        (void*)offsetof(Vertex, tu));
-  glEnableVertexAttribArray(g_texCoordLoc);
-  glVertexAttribPointer(g_colorLoc,
-                        3,
-                        GL_FLOAT,
-                        GL_FALSE,
-                        sizeof(Vertex),
-                        (void*)offsetof(Vertex, color));
-  glEnableVertexAttribArray(g_colorLoc);
-
-  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ibID);
-  glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_BYTE, 0);
-}
-
-const char* LoadData(const char* url) {
-  char* buf;
-  struct stat stat_buf;
-
-  int fp = open(url, O_RDONLY);
-  fstat(fp, &stat_buf);
-
-  int len = static_cast<int>(stat_buf.st_size);
-  buf = new char[len + 1];
-  int read_size = read(fp, buf, len);
-  buf[len] = 0;
-  return buf;
-}
-
-PPAPI_MAIN_USE(PPAPI_CreateInstance3D, PPAPI_MAIN_DEFAULT_ARGS)
-int ppapi_main(int argc, const char* argv[]) {
-  printf("Started main.\n");
-
-  // Mount URL loads to /http
-  mount("", "/http", "httpfs", 0, "");
-
-  g_TextureData = LoadData("/http/hello.raw");
-  g_VShaderData = LoadData("/http/vertex_shader_es2.vert");
-  g_FShaderData = LoadData("/http/fragment_shader_es2.frag");
-  g_quadVertices = BuildCube();
-
-  fprintf(stderr, "Loaded\n");
-  g_Loaded = true;
-  return 0;
-}
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/matrix.cc b/native_client_sdk/src/examples/hello_world_instance3d/matrix.cc
deleted file mode 100644
index b87d496cb1..0000000000
--- a/native_client_sdk/src/examples/hello_world_instance3d/matrix.cc
+++ /dev/null
@@ -1,140 +0,0 @@
-/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-/** @file matrix.cc
- * Implements simple matrix manipulation functions.
- */
-
-//-----------------------------------------------------------------------------
-#include <stdlib.h>
-#include <string.h>
-#include "matrix.h"
-#define deg_to_rad(x) (x * (M_PI / 180.0f))
-
-void glhFrustumf2(Matrix_t mat,
-                  GLfloat left,
-                  GLfloat right,
-                  GLfloat bottom,
-                  GLfloat top,
-                  GLfloat znear,
-                  GLfloat zfar) {
-  float temp, temp2, temp3, temp4;
-  temp = 2.0f * znear;
-  temp2 = right - left;
-  temp3 = top - bottom;
-  temp4 = zfar - znear;
-  mat[0] = temp / temp2;
-  mat[1] = 0.0f;
-  mat[2] = 0.0f;
-  mat[3] = 0.0f;
-  mat[4] = 0.0f;
-  mat[5] = temp / temp3;
-  mat[6] = 0.0f;
-  mat[7] = 0.0f;
-  mat[8] = (right + left) / temp2;
-  mat[9] = (top + bottom) / temp3;
-  mat[10] = (-zfar - znear) / temp4;
-  mat[11] = -1.0f;
-  mat[12] = 0.0f;
-  mat[13] = 0.0f;
-  mat[14] = (-temp * zfar) / temp4;
-  mat[15] = 0.0f;
-}
-
-void glhPerspectivef2(Matrix_t mat,
-                      GLfloat fovyInDegrees,
-                      GLfloat aspectRatio,
-                      GLfloat znear,
-                      GLfloat zfar) {
-  float ymax, xmax;
-  ymax = znear * tanf(fovyInDegrees * 3.14f / 360.0f);
-  xmax = ymax * aspectRatio;
-  glhFrustumf2(mat, -xmax, xmax, -ymax, ymax, znear, zfar);
-}
-
-void identity_matrix(Matrix_t mat) {
-  memset(mat, 0, sizeof(Matrix_t));
-  mat[0] = 1.0;
-  mat[5] = 1.0;
-  mat[10] = 1.0;
-  mat[15] = 1.0;
-}
-
-void multiply_matrix(const Matrix_t a, const Matrix_t b, Matrix_t mat) {
-  // Generate to a temporary first in case the output matrix and input
-  // matrix are the same.
-  Matrix_t out;
-
-  out[0] = a[0] * b[0] + a[4] * b[1] + a[8] * b[2] + a[12] * b[3];
-  out[1] = a[1] * b[0] + a[5] * b[1] + a[9] * b[2] + a[13] * b[3];
-  out[2] = a[2] * b[0] + a[6] * b[1] + a[10] * b[2] + a[14] * b[3];
-  out[3] = a[3] * b[0] + a[7] * b[1] + a[11] * b[2] + a[15] * b[3];
-
-  out[4] = a[0] * b[4] + a[4] * b[5] + a[8] * b[6] + a[12] * b[7];
-  out[5] = a[1] * b[4] + a[5] * b[5] + a[9] * b[6] + a[13] * b[7];
-  out[6] = a[2] * b[4] + a[6] * b[5] + a[10] * b[6] + a[14] * b[7];
-  out[7] = a[3] * b[4] + a[7] * b[5] + a[11] * b[6] + a[15] * b[7];
-
-  out[8] = a[0] * b[8] + a[4] * b[9] + a[8] * b[10] + a[12] * b[11];
-  out[9] = a[1] * b[8] + a[5] * b[9] + a[9] * b[10] + a[13] * b[11];
-  out[10] = a[2] * b[8] + a[6] * b[9] + a[10] * b[10] + a[14] * b[11];
-  out[11] = a[3] * b[8] + a[7] * b[9] + a[11] * b[10] + a[15] * b[11];
-
-  out[12] = a[0] * b[12] + a[4] * b[13] + a[8] * b[14] + a[12] * b[15];
-  out[13] = a[1] * b[12] + a[5] * b[13] + a[9] * b[14] + a[13] * b[15];
-  out[14] = a[2] * b[12] + a[6] * b[13] + a[10] * b[14] + a[14] * b[15];
-  out[15] = a[3] * b[12] + a[7] * b[13] + a[11] * b[14] + a[15] * b[15];
-
-  memcpy(mat, out, sizeof(Matrix_t));
-}
-
-void rotate_x_matrix(GLfloat x_rad, Matrix_t mat) {
-  identity_matrix(mat);
-  mat[5] = cosf(x_rad);
-  mat[6] = -sinf(x_rad);
-  mat[9] = -mat[6];
-  mat[10] = mat[5];
-}
-
-void rotate_y_matrix(GLfloat y_rad, Matrix_t mat) {
-  identity_matrix(mat);
-  mat[0] = cosf(y_rad);
-  mat[2] = sinf(y_rad);
-  mat[8] = -mat[2];
-  mat[10] = mat[0];
-}
-
-void rotate_z_matrix(GLfloat z_rad, Matrix_t mat) {
-  identity_matrix(mat);
-  mat[0] = cosf(z_rad);
-  mat[1] = sinf(z_rad);
-  mat[4] = -mat[1];
-  mat[5] = mat[0];
-}
-
-void rotate_matrix(GLfloat x_deg, GLfloat y_deg, GLfloat z_deg, Matrix_t mat) {
-  GLfloat x_rad = (GLfloat) deg_to_rad(x_deg);
-  GLfloat y_rad = (GLfloat) deg_to_rad(y_deg);
-  GLfloat z_rad = (GLfloat) deg_to_rad(z_deg);
-
-  Matrix_t x_matrix;
-  Matrix_t y_matrix;
-  Matrix_t z_matrix;
-
-  rotate_x_matrix(x_rad, x_matrix);
-  rotate_y_matrix(y_rad, y_matrix);
-  rotate_z_matrix(z_rad, z_matrix);
-
-  Matrix_t xy_matrix;
-  multiply_matrix(y_matrix, x_matrix, xy_matrix);
-  multiply_matrix(z_matrix, xy_matrix, mat);
-}
-
-void translate_matrix(GLfloat x, GLfloat y, GLfloat z, Matrix_t mat) {
-  identity_matrix(mat);
-  mat[12] += x;
-  mat[13] += y;
-  mat[14] += z;
-}
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/matrix.h b/native_client_sdk/src/examples/hello_world_instance3d/matrix.h
deleted file mode 100644
index ed094eda09..0000000000
--- a/native_client_sdk/src/examples/hello_world_instance3d/matrix.h
+++ /dev/null
@@ -1,43 +0,0 @@
-#ifndef EXAMPLES_HELLO_WORLD_GLES_MATRIX_H
-#define EXAMPLES_HELLO_WORLD_GLES_MATRIX_H
-
-/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-/** @file matrix.cc
- * Implements simple matrix manipulation functions.
- */
-
-//-----------------------------------------------------------------------------
-#define _USE_MATH_DEFINES 1
-#include <limits.h>
-#include <math.h>
-#include <GLES2/gl2.h>
-
-typedef GLfloat Matrix_t[16];
-
-/// Since GLES2 doesn't have all the nifty matrix transform functions that GL
-/// has, we emulate some of them here for the sake of sanity from:
-/// http://www.opengl.org/wiki/GluPerspective_code
-void glhFrustumf2(Matrix_t mat,
-                  GLfloat left,
-                  GLfloat right,
-                  GLfloat bottom,
-                  GLfloat top,
-                  GLfloat znear,
-                  GLfloat zfar);
-
-void glhPerspectivef2(Matrix_t mat,
-                      GLfloat fovyInDegrees,
-                      GLfloat aspectRatio,
-                      GLfloat znear,
-                      GLfloat zfar);
-
-void identity_matrix(Matrix_t mat);
-void multiply_matrix(const Matrix_t a, const Matrix_t b, Matrix_t mat);
-void rotate_matrix(GLfloat x_deg, GLfloat y_deg, GLfloat z_deg, Matrix_t mat);
-void translate_matrix(GLfloat x, GLfloat y, GLfloat z, Matrix_t mat);
-
-#endif  // EXAMPLES_HELLO_WORLD_GLES_MATRIX_H
diff --git a/native_client_sdk/src/examples/hello_world_instance3d/vertex_shader_es2.vert b/native_client_sdk/src/examples/hello_world_instance3d/vertex_shader_es2.vert
deleted file mode 100644
index da616cb92a..0000000000
--- a/native_client_sdk/src/examples/hello_world_instance3d/vertex_shader_es2.vert
+++ /dev/null
@@ -1,12 +0,0 @@
-uniform mat4 a_MVP;
-attribute vec2 a_texCoord; 
-attribute vec3 a_color; 
-attribute vec4 a_position; 
-varying  vec3 v_color; 
-varying  vec2 v_texCoord; 
-void main() 
-{
- gl_Position = a_MVP * a_position; 
- v_color = a_color;
- v_texCoord = a_texCoord;
-}
\ No newline at end of file
diff --git a/native_client_sdk/src/examples/tutorial/dlopen/dlopen.cc b/native_client_sdk/src/examples/tutorial/dlopen/dlopen.cc
index 7d13a1028e..9291464165 100644
--- a/native_client_sdk/src/examples/tutorial/dlopen/dlopen.cc
+++ b/native_client_sdk/src/examples/tutorial/dlopen/dlopen.cc
@@ -23,9 +23,15 @@
 #define CONFIG_NAME "Release"
 #endif
 
-#define XSTRINGIFY(x) STRINGIFY(x)
-#define STRINGIFY(x) #x
-#define NACL_ARCH_STRING XSTRINGIFY(NACL_ARCH)
+#if defined __arm__
+#define NACL_ARCH "arm"
+#elif defined __i686__
+#define NACL_ARCH "x86_32"
+#elif defined __x86_64__
+#define NACL_ARCH "x86_64"
+#else
+#error "Unknown arch"
+#endif
 
 class DlOpenInstance : public pp::Instance {
  public:
@@ -66,7 +72,7 @@ class DlOpenInstance : public pp::Instance {
   // dlclose, which would close the shared object and unload it from memory.
   void LoadLibrary() {
     const char reverse_so_path[] =
-        "/http/glibc/" CONFIG_NAME "/libreverse_" NACL_ARCH_STRING ".so";
+        "/http/glibc/" CONFIG_NAME "/libreverse_" NACL_ARCH ".so";
     const int32_t IMMEDIATELY = 0;
     eightball_so_ = dlopen("libeightball.so", RTLD_LAZY);
     reverse_so_ = dlopen(reverse_so_path, RTLD_LAZY);
diff --git a/native_client_sdk/src/libraries/error_handling/error_handling.h b/native_client_sdk/src/libraries/error_handling/error_handling.h
index 29b4aca96d..add76ceb41 100644
--- a/native_client_sdk/src/libraries/error_handling/error_handling.h
+++ b/native_client_sdk/src/libraries/error_handling/error_handling.h
@@ -8,7 +8,7 @@
 #define ERROR_HANDLING_ERROR_HANDLING_H_
 
 #include "error_handling/string_stream.h"
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 EXTERN_C_BEGIN
 
@@ -82,4 +82,5 @@ int EHUnwindFrame(EHFrame* frame);
 
 EXTERN_C_END
 
-#endif  // ERROR_HANDLING_ERROR_HANDLING_H_
\ No newline at end of file
+#endif  // ERROR_HANDLING_ERROR_HANDLING_H_
+
diff --git a/native_client_sdk/src/libraries/nacl_io/error.h b/native_client_sdk/src/libraries/nacl_io/error.h
new file mode 100644
index 0000000000..8f7510e46e
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/error.h
@@ -0,0 +1,17 @@
+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#ifndef LIBRARIES_NACL_IO_ERROR_H_
+#define LIBRARIES_NACL_IO_ERROR_H_
+
+struct Error {
+  // TODO(binji): Add debugging constructor w/ __FILE__, __LINE__.
+  // crbug.com/247816
+  Error(int error) : error(error) {}
+  operator int() const { return error; }
+
+  int error;
+};
+
+#endif  // LIBRARIES_NACL_IO_ERROR_H_
diff --git a/native_client_sdk/src/libraries/nacl_io/inode_pool.h b/native_client_sdk/src/libraries/nacl_io/inode_pool.h
index 5624b1d17a..4c3f44b36e 100644
--- a/native_client_sdk/src/libraries/nacl_io/inode_pool.h
+++ b/native_client_sdk/src/libraries/nacl_io/inode_pool.h
@@ -11,7 +11,7 @@
 
 #include "nacl_io/osstat.h"
 #include "pthread.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
 
 
 class INodePool {
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_handle.cc b/native_client_sdk/src/libraries/nacl_io/kernel_handle.cc
index dcf42fb8c6..a943894595 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_handle.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_handle.cc
@@ -17,40 +17,57 @@
 #include "nacl_io/mount_node.h"
 
 // It is only legal to construct a handle while the kernel lock is held.
-KernelHandle::KernelHandle(Mount* mnt, MountNode* node, int mode)
-    : mount_(mnt),
-      node_(node),
-      mode_(mode),
-      offs_(0) {
-  if (mode & O_APPEND) offs_ = node->GetSize();
+KernelHandle::KernelHandle(Mount* mnt, MountNode* node)
+    : mount_(mnt), node_(node), offs_(0) {}
+
+Error KernelHandle::Init(int open_mode) {
+  if (open_mode & O_APPEND) {
+    size_t node_size;
+    Error error = node_->GetSize(&offs_);
+    if (error)
+      return error;
+  }
+
+  return 0;
 }
 
-off_t KernelHandle::Seek(off_t offset, int whence) {
+Error KernelHandle::Seek(off_t offset, int whence, off_t* out_offset) {
+  // By default, don't move the offset.
+  *out_offset = offset;
+
   size_t base;
-  size_t node_size = node_->GetSize();
+  size_t node_size;
+  Error error = node_->GetSize(&node_size);
+  if (error)
+    return error;
 
   switch (whence) {
-    default: return -1;
-    case SEEK_SET: base = 0; break;
-    case SEEK_CUR: base = offs_; break;
-    case SEEK_END: base = node_size; break;
+    default:
+      return -1;
+    case SEEK_SET:
+      base = 0;
+      break;
+    case SEEK_CUR:
+      base = offs_;
+      break;
+    case SEEK_END:
+      base = node_size;
+      break;
   }
 
-  if (base + offset < 0) {
-    errno = EINVAL;
-    return -1;
-  }
+  if (base + offset < 0)
+    return EINVAL;
 
-  offs_ = base + offset;
+  off_t new_offset = base + offset;
 
   // Seeking past the end of the file will zero out the space between the old
   // end and the new end.
-  if (offs_ > node_size) {
-    if (node_->FTruncate(offs_) < 0) {
-      errno = EINVAL;
-      return -1;
-    }
+  if (new_offset > node_size) {
+    error = node_->FTruncate(new_offset);
+    if (error)
+      return EINVAL;
   }
 
-  return offs_;
+  *out_offset = offs_ = new_offset;
+  return 0;
 }
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_handle.h b/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
index a047125085..ab7b7cd699 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_handle.h
@@ -7,9 +7,10 @@
 
 #include <pthread.h>
 
+#include "nacl_io/error.h"
 #include "nacl_io/ostypes.h"
-#include "utils/macros.h"
-#include "utils/ref_object.h"
+#include "sdk_util/macros.h"
+#include "sdk_util/ref_object.h"
 
 class Mount;
 class MountNode;
@@ -19,13 +20,15 @@ class MountNode;
 // KernelHandle can only be referenced when the KernelProxy lock is held.
 class KernelHandle : public RefObject {
  public:
-  KernelHandle(Mount* mnt, MountNode* node, int oflags);
+  // Assumes |mnt| and |node| are non-NULL.
+  KernelHandle(Mount* mnt, MountNode* node);
 
-  off_t Seek(off_t offset, int whence);
+  Error Init(int open_flags);
+  // Assumes |out_offset| is non-NULL.
+  Error Seek(off_t offset, int whence, off_t* out_offset);
 
   Mount* mount_;
   MountNode* node_;
-  int mode_;
   size_t offs_;
 
  private:
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_intercept.h b/native_client_sdk/src/libraries/nacl_io/kernel_intercept.h
index b1bcf90d7c..c4b658dfd4 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_intercept.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_intercept.h
@@ -8,7 +8,7 @@
 #include <ppapi/c/ppb.h>
 #include <ppapi/c/pp_instance.h>
 #include "nacl_io/ostypes.h"
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 EXTERN_C_BEGIN
 
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_object.cc b/native_client_sdk/src/libraries/nacl_io/kernel_object.cc
index 5c265309cc..6be3c9779b 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_object.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_object.cc
@@ -17,7 +17,7 @@
 #include "nacl_io/kernel_handle.h"
 #include "nacl_io/mount.h"
 #include "nacl_io/mount_node.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
 
 KernelObject::KernelObject() {
   pthread_mutex_init(&kernel_lock_, NULL);
@@ -31,8 +31,12 @@ KernelObject::~KernelObject() {
 
 // Uses longest prefix to find the mount for the give path, then
 // acquires the mount and returns it with a relative path.
-Mount* KernelObject::AcquireMountAndPath(const std::string& relpath,
-                                         Path* out_path) {
+Error KernelObject::AcquireMountAndPath(const std::string& relpath,
+                                        Mount** out_mount,
+                                        Path* out_path) {
+  *out_mount = NULL;
+  *out_path = Path();
+
   Path abs_path;
   {
     AutoLock lock(&process_lock_);
@@ -42,7 +46,6 @@ Mount* KernelObject::AcquireMountAndPath(const std::string& relpath,
   AutoLock lock(&kernel_lock_);
   Mount* mount = NULL;
 
-
   // Find longest prefix
   size_t max = abs_path.Size();
   for (size_t len = 0; len < abs_path.Size(); len++) {
@@ -55,14 +58,13 @@ Mount* KernelObject::AcquireMountAndPath(const std::string& relpath,
     }
   }
 
-  if (NULL == mount) {
-    errno = ENOTDIR;
-    return NULL;
-  }
+  if (NULL == mount)
+    return ENOTDIR;
 
   // Acquire the mount while we hold the proxy lock
   mount->Acquire();
-  return mount;
+  *out_mount = mount;
+  return 0;
 }
 
 void KernelObject::ReleaseMount(Mount* mnt) {
@@ -70,43 +72,38 @@ void KernelObject::ReleaseMount(Mount* mnt) {
   mnt->Release();
 }
 
-KernelHandle* KernelObject::AcquireHandle(int fd) {
+Error KernelObject::AcquireHandle(int fd, KernelHandle** out_handle) {
+  *out_handle = NULL;
+
   AutoLock lock(&process_lock_);
-  if (fd < 0 || fd >= static_cast<int>(handle_map_.size())) {
-    errno = EBADF;
-    return NULL;
-  }
+  if (fd < 0 || fd >= static_cast<int>(handle_map_.size()))
+    return EBADF;
 
   KernelHandle* handle = handle_map_[fd];
-  if (NULL == handle) {
-    errno = EBADF;
-    return NULL;
-  }
+  if (NULL == handle)
+    return EBADF;
 
   // Ref count while holding parent mutex
   handle->Acquire();
 
   lock.Unlock();
-  if (handle->node_) handle->mount_->AcquireNode(handle->node_);
+  if (handle->node_)
+    handle->mount_->AcquireNode(handle->node_);
 
-  return handle;
+  *out_handle = handle;
+  return 0;
 }
 
 void KernelObject::ReleaseHandle(KernelHandle* handle) {
   // The handle must already be held before taking the
   // kernel lock.
-  if (handle->node_) handle->mount_->ReleaseNode(handle->node_);
+  if (handle->node_)
+    handle->mount_->ReleaseNode(handle->node_);
 
   AutoLock lock(&process_lock_);
   handle->Release();
 }
 
-// Helper function to properly sort FD order in the heap, forcing
-// lower numbered FD to be available first.
-static bool FdOrder(int i, int j) {
-  return i > j;
-}
-
 int KernelObject::AllocateFD(KernelHandle* handle) {
   AutoLock lock(&process_lock_);
   int id;
@@ -119,7 +116,8 @@ int KernelObject::AllocateFD(KernelHandle* handle) {
   // If we can recycle and FD, use that first
   if (free_fds_.size()) {
     id = free_fds_.front();
-    std::pop_heap(free_fds_.begin(), free_fds_.end(), FdOrder);
+    // Force lower numbered FD to be available first.
+    std::pop_heap(free_fds_.begin(), free_fds_.end(), std::greater<int>());
     free_fds_.pop_back();
     handle_map_[id] = handle;
   } else {
@@ -166,7 +164,8 @@ void KernelObject::FreeFD(int fd) {
 
   handle_map_[fd] = NULL;
   free_fds_.push_back(fd);
-  std::push_heap(free_fds_.begin(), free_fds_.end(), FdOrder);
+  // Force lower numbered FD to be available first.
+  std::push_heap(free_fds_.begin(), free_fds_.end(), std::greater<int>());
 }
 
 Path KernelObject::GetAbsPathLocked(const std::string& path) {
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_object.h b/native_client_sdk/src/libraries/nacl_io/kernel_object.h
index 97b197f805..eb4c8ac041 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_object.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_object.h
@@ -11,6 +11,7 @@
 #include <string>
 #include <vector>
 
+#include "nacl_io/error.h"
 #include "nacl_io/path.h"
 
 class KernelHandle;
@@ -28,17 +29,25 @@ class KernelObject {
   KernelObject();
   virtual ~KernelObject();
 
-  // Find the mount for the given path, and acquires it
-  Mount* AcquireMountAndPath(const std::string& relpath, Path *pobj);
+  // Find the mount for the given path, and acquires it.
+  // Assumes |out_mount| and |out_path| are non-NULL.
+  Error AcquireMountAndPath(const std::string& relpath,
+                            Mount** out_mount,
+                            Path* out_path);
+  // Assumes |mnt| is non-NULL.
   void ReleaseMount(Mount* mnt);
 
   // Convert from FD to KernelHandle, and acquire the handle.
-  KernelHandle* AcquireHandle(int fd);
+  // Assumes |out_handle| is non-NULL.
+  Error AcquireHandle(int fd, KernelHandle** out_handle);
+  // Assumes |handle| is non-NULL.
   void ReleaseHandle(KernelHandle* handle);
 
   // Allocate a new fd and assign the handle to it, while
   // ref counting the handle and associated mount.
+  // Assumes |handle| is non-NULL;
   int AllocateFD(KernelHandle* handle);
+  // Assumes |handle| is non-NULL;
   void FreeAndReassignFD(int fd, KernelHandle* handle);
   void FreeFD(int fd);
 
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
index 6d996d3ae2..2f49395ee0 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc
@@ -25,8 +25,8 @@
 #include "nacl_io/osstat.h"
 #include "nacl_io/path.h"
 #include "nacl_io/pepper_interface.h"
-#include "utils/auto_lock.h"
-#include "utils/ref_object.h"
+#include "sdk_util/auto_lock.h"
+#include "sdk_util/ref_object.h"
 
 #ifndef MAXPATHLEN
 #define MAXPATHLEN 256
@@ -36,16 +36,9 @@
 #define USR_ID 1002
 #define GRP_ID 1003
 
+KernelProxy::KernelProxy() : dev_(0), ppapi_(NULL) {}
 
-
-KernelProxy::KernelProxy()
-   : dev_(0),
-     ppapi_(NULL) {
-}
-
-KernelProxy::~KernelProxy() {
-  delete ppapi_;
-}
+KernelProxy::~KernelProxy() { delete ppapi_; }
 
 void KernelProxy::Init(PepperInterface* ppapi) {
   ppapi_ = ppapi;
@@ -58,11 +51,12 @@ void KernelProxy::Init(PepperInterface* ppapi) {
   factories_["httpfs"] = MountHttp::Create<MountHttp>;
   factories_["passthroughfs"] = MountPassthrough::Create<MountPassthrough>;
 
-  // Create passthrough mount at root
-  StringMap_t smap;
-  mounts_["/"] = MountPassthrough::Create<MountPassthrough>(
-      dev_++, smap, ppapi_);
-  mounts_["/dev"] = MountDev::Create<MountDev>(dev_++, smap, ppapi_);
+  int result;
+  result = mount("", "/", "passthroughfs", 0, NULL);
+  assert(result == 0);
+
+  result = mount("", "/dev", "dev", 0, NULL);
+  assert(result == 0);
 
   // Open the first three in order to get STDIN, STDOUT, STDERR
   open("/dev/stdin", O_RDONLY);
@@ -70,19 +64,32 @@ void KernelProxy::Init(PepperInterface* ppapi) {
   open("/dev/stderr", O_WRONLY);
 }
 
-int KernelProxy::open(const char *path, int oflags) {
+int KernelProxy::open(const char* path, int oflags) {
   Path rel;
 
-  Mount* mnt = AcquireMountAndPath(path, &rel);
-  if (mnt == NULL) return -1;
+  Mount* mnt;
+  Error error = AcquireMountAndPath(path, &mnt, &rel);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
-  MountNode* node = mnt->Open(rel, oflags);
-  if (node == NULL) {
+  MountNode* node = NULL;
+  error = mnt->Open(rel, oflags, &node);
+  if (error) {
+    errno = error;
+    ReleaseMount(mnt);
+    return -1;
+  }
+
+  KernelHandle* handle = new KernelHandle(mnt, node);
+  error = handle->Init(oflags);
+  if (error) {
+    errno = error;
     ReleaseMount(mnt);
     return -1;
   }
 
-  KernelHandle* handle = new KernelHandle(mnt, node, oflags);
   int fd = AllocateFD(handle);
   mnt->AcquireNode(node);
 
@@ -93,9 +100,12 @@ int KernelProxy::open(const char *path, int oflags) {
 }
 
 int KernelProxy::close(int fd) {
-  KernelHandle* handle = AcquireHandle(fd);
-
-  if (NULL == handle) return -1;
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
   Mount* mount = handle->mount_;
   // Acquire the mount to ensure FreeFD doesn't prematurely destroy it.
@@ -115,8 +125,12 @@ int KernelProxy::close(int fd) {
 }
 
 int KernelProxy::dup(int oldfd) {
-  KernelHandle* handle = AcquireHandle(oldfd);
-  if (NULL == handle) return -1;
+  KernelHandle* handle;
+  Error error = AcquireHandle(oldfd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
   int newfd = AllocateFD(handle);
   ReleaseHandle(handle);
@@ -126,17 +140,21 @@ int KernelProxy::dup(int oldfd) {
 
 int KernelProxy::dup2(int oldfd, int newfd) {
   // If it's the same file handle, just return
-  if (oldfd == newfd) return newfd;
+  if (oldfd == newfd)
+    return newfd;
 
-  KernelHandle* old_handle = AcquireHandle(oldfd);
-  if (NULL == old_handle) return -1;
+  KernelHandle* old_handle;
+  Error error = AcquireHandle(oldfd, &old_handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
   FreeAndReassignFD(newfd, old_handle);
   ReleaseHandle(old_handle);
   return newfd;
 }
 
-
 char* KernelProxy::getcwd(char* buf, size_t size) {
   AutoLock lock(&process_lock_);
   if (size <= 0) {
@@ -171,42 +189,64 @@ char* KernelProxy::getwd(char* buf) {
   return getcwd(buf, MAXPATHLEN);
 }
 
-int KernelProxy::chmod(const char *path, mode_t mode) {
+int KernelProxy::chmod(const char* path, mode_t mode) {
   int fd = KernelProxy::open(path, O_RDWR);
-  if (-1 == fd) return -1;
+  if (-1 == fd)
+    return -1;
 
-  int ret = fchmod(fd, mode);
+  int result = fchmod(fd, mode);
   close(fd);
-  return ret;
+  return result;
 }
 
-int KernelProxy::mkdir(const char *path, mode_t mode) {
+int KernelProxy::mkdir(const char* path, mode_t mode) {
+  Mount* mnt;
   Path rel;
-  Mount* mnt = AcquireMountAndPath(path, &rel);
-  if (mnt == NULL) return -1;
+  Error error = AcquireMountAndPath(path, &mnt, &rel);
+  if (error) {
+    errno = error;
+    return -1;
+  }
+
+  int result = 0;
+  error = mnt->Mkdir(rel, mode);
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
-  int val = mnt->Mkdir(rel, mode);
   ReleaseMount(mnt);
-  return val;
+  return result;
 }
 
-int KernelProxy::rmdir(const char *path) {
+int KernelProxy::rmdir(const char* path) {
+  Mount* mnt;
   Path rel;
-  Mount* mnt = AcquireMountAndPath(path, &rel);
-  if (mnt == NULL) return -1;
+  Error error = AcquireMountAndPath(path, &mnt, &rel);
+  if (error) {
+    errno = error;
+    return -1;
+  }
+
+  int result = 0;
+  error = mnt->Rmdir(rel);
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
-  int val = mnt->Rmdir(rel);
   ReleaseMount(mnt);
-  return val;
+  return result;
 }
 
-int KernelProxy::stat(const char *path, struct stat *buf) {
+int KernelProxy::stat(const char* path, struct stat* buf) {
   int fd = open(path, O_RDONLY);
-  if (-1 == fd) return -1;
+  if (-1 == fd)
+    return -1;
 
-  int ret = fstat(fd, buf);
+  int result = fstat(fd, buf);
   close(fd);
-  return ret;
+  return result;
 }
 
 int KernelProxy::chdir(const char* path) {
@@ -215,19 +255,21 @@ int KernelProxy::chdir(const char* path) {
     return -1;
 
   bool is_dir = (statbuf.st_mode & S_IFDIR) != 0;
-  if (is_dir) {
-    AutoLock lock(&process_lock_);
-    cwd_ = GetAbsPathLocked(path).Join();
-    return 0;
+  if (!is_dir) {
+    errno = ENOTDIR;
+    return -1;
   }
 
-  errno = ENOTDIR;
-  return -1;
+  AutoLock lock(&process_lock_);
+  cwd_ = GetAbsPathLocked(path).Join();
+  return 0;
 }
 
-int KernelProxy::mount(const char *source, const char *target,
-                       const char *filesystemtype, unsigned long mountflags,
-                       const void *data) {
+int KernelProxy::mount(const char* source,
+                       const char* target,
+                       const char* filesystemtype,
+                       unsigned long mountflags,
+                       const void* data) {
   // See if it's already mounted
   std::string abs_targ;
 
@@ -255,8 +297,8 @@ int KernelProxy::mount(const char *source, const char *target,
   smap["TARGET"] = abs_targ;
 
   if (data) {
-    char* str = strdup(static_cast<const char *>(data));
-    char* ptr = strtok(str,",");
+    char* str = strdup(static_cast<const char*>(data));
+    char* ptr = strtok(str, ",");
     char* val;
     while (ptr != NULL) {
       val = strchr(ptr, '=');
@@ -271,16 +313,18 @@ int KernelProxy::mount(const char *source, const char *target,
     free(str);
   }
 
-  Mount* mnt = factory->second(dev_++, smap, ppapi_);
-  if (mnt) {
-    mounts_[abs_targ] = mnt;
-    return 0;
+  Mount* mnt = NULL;
+  Error error = factory->second(dev_++, smap, ppapi_, &mnt);
+  if (error) {
+    errno = error;
+    return -1;
   }
-  errno = EINVAL;
-  return -1;
+
+  mounts_[abs_targ] = mnt;
+  return 0;
 }
 
-int KernelProxy::umount(const char *path) {
+int KernelProxy::umount(const char* path) {
   Path abs_path;
 
   // Scope this lock to prevent holding both process and kernel locks
@@ -307,125 +351,204 @@ int KernelProxy::umount(const char *path) {
   return 0;
 }
 
-ssize_t KernelProxy::read(int fd, void *buf, size_t nbytes) {
-  KernelHandle* handle = AcquireHandle(fd);
-
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
+ssize_t KernelProxy::read(int fd, void* buf, size_t nbytes) {
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
   AutoLock lock(&handle->lock_);
-  ssize_t cnt = handle->node_->Read(handle->offs_, buf, nbytes);
-  if (cnt > 0) handle->offs_ += cnt;
+  int cnt = 0;
+  error = handle->node_->Read(handle->offs_, buf, nbytes, &cnt);
+  if (error)
+    errno = error;
+
+  if (cnt > 0)
+    handle->offs_ += cnt;
 
   ReleaseHandle(handle);
   return cnt;
 }
 
-ssize_t KernelProxy::write(int fd, const void *buf, size_t nbytes) {
-  KernelHandle* handle = AcquireHandle(fd);
-
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
+ssize_t KernelProxy::write(int fd, const void* buf, size_t nbytes) {
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
   AutoLock lock(&handle->lock_);
-  ssize_t cnt = handle->node_->Write(handle->offs_, buf, nbytes);
-  if (cnt > 0) handle->offs_ += cnt;
+  int cnt = 0;
+  error = handle->node_->Write(handle->offs_, buf, nbytes, &cnt);
+  if (error)
+    errno = error;
+
+  if (cnt > 0)
+    handle->offs_ += cnt;
 
   ReleaseHandle(handle);
   return cnt;
 }
 
 int KernelProxy::fstat(int fd, struct stat* buf) {
-  KernelHandle* handle = AcquireHandle(fd);
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
+  int result = 0;
+  error = handle->node_->GetStat(buf);
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
-  int ret = handle->node_->GetStat(buf);
   ReleaseHandle(handle);
-  return ret;
+  return result;
 }
 
 int KernelProxy::getdents(int fd, void* buf, unsigned int count) {
-  KernelHandle* handle = AcquireHandle(fd);
-
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
   AutoLock lock(&handle->lock_);
-  int cnt = handle->node_->GetDents(handle->offs_,
-      static_cast<dirent *>(buf), count);
+  int cnt = 0;
+  error = handle->node_
+      ->GetDents(handle->offs_, static_cast<dirent*>(buf), count, &cnt);
+  if (error)
+    errno = error;
 
-  if (cnt > 0) handle->offs_ += cnt;
+  if (cnt > 0)
+    handle->offs_ += cnt;
 
   ReleaseHandle(handle);
   return cnt;
 }
 
 int KernelProxy::ftruncate(int fd, off_t length) {
-  KernelHandle* handle = AcquireHandle(fd);
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
-  int ret = handle->node_->FTruncate(length);
+  int result = 0;
+  error = handle->node_->FTruncate(length);
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
   ReleaseHandle(handle);
-  return ret;
+  return result;
 }
 
 int KernelProxy::fsync(int fd) {
-  KernelHandle* handle = AcquireHandle(fd);
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
-  int ret = handle->node_->FSync();
+  int result = 0;
+  error = handle->node_->FSync();
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
   ReleaseHandle(handle);
-  return ret;
+  return result;
 }
 
 int KernelProxy::isatty(int fd) {
-  KernelHandle* handle = AcquireHandle(fd);
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
-  int ret = handle->node_->IsaTTY();
+  int result = 0;
+  error = handle->node_->IsaTTY();
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
   ReleaseHandle(handle);
-  return ret;
+  return result;
 }
 
 off_t KernelProxy::lseek(int fd, off_t offset, int whence) {
-  KernelHandle* handle = AcquireHandle(fd);
-
-  // check if fd is valid and handle exists
-  if (NULL == handle) return -1;
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
   AutoLock lock(&handle->lock_);
-  int ret = handle->Seek(offset, whence);
+  off_t new_offset;
+  error = handle->Seek(offset, whence, &new_offset);
+  if (error) {
+    errno = error;
+    new_offset = -1;
+  }
 
   ReleaseHandle(handle);
-  return ret;
+  return new_offset;
 }
 
 int KernelProxy::unlink(const char* path) {
+  Mount* mnt;
   Path rel;
-  Mount* mnt = AcquireMountAndPath(path, &rel);
-  if (mnt == NULL) return -1;
+  Error error = AcquireMountAndPath(path, &mnt, &rel);
+  if (error) {
+    errno = error;
+    return -1;
+  }
+
+  int result = 0;
+  error = mnt->Unlink(rel);
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
-  int val = mnt->Unlink(rel);
   ReleaseMount(mnt);
-  return val;
+  return result;
 }
 
 int KernelProxy::remove(const char* path) {
+  Mount* mnt;
   Path rel;
-  Mount* mnt = AcquireMountAndPath(path, &rel);
-  if (mnt == NULL) return -1;
+  Error error = AcquireMountAndPath(path, &mnt, &rel);
+  if (error) {
+    errno = error;
+    return -1;
+  }
+
+  int result = 0;
+  error = mnt->Remove(rel);
+  if (error) {
+    errno = error;
+    result = -1;
+  }
 
-  int val = mnt->Remove(rel);
   ReleaseMount(mnt);
-  return val;
+  return result;
 }
 
 // TODO(noelallen): Needs implementation.
@@ -449,22 +572,29 @@ int KernelProxy::symlink(const char* oldpath, const char* newpath) {
   return -1;
 }
 
-void* KernelProxy::mmap(void* addr, size_t length, int prot, int flags, int fd,
+void* KernelProxy::mmap(void* addr,
+                        size_t length,
+                        int prot,
+                        int flags,
+                        int fd,
                         size_t offset) {
   // We shouldn't be getting anonymous mmaps here.
   assert((flags & MAP_ANONYMOUS) == 0);
   assert(fd != -1);
 
-  KernelHandle* handle = AcquireHandle(fd);
-
-  if (NULL == handle)
+  KernelHandle* handle;
+  Error error = AcquireHandle(fd, &handle);
+  if (error) {
+    errno = error;
     return MAP_FAILED;
+  }
 
   void* new_addr;
   {
     AutoLock lock(&handle->lock_);
-    new_addr = handle->node_->MMap(addr, length, prot, flags, offset);
-    if (new_addr == MAP_FAILED) {
+    error = handle->node_->MMap(addr, length, prot, flags, offset, &new_addr);
+    if (error) {
+      errno = error;
       ReleaseHandle(handle);
       return MAP_FAILED;
     }
@@ -510,23 +640,34 @@ int KernelProxy::munmap(void* addr, size_t length) {
 }
 
 int KernelProxy::open_resource(const char* path) {
+  Mount* mnt;
   Path rel;
+  Error error = AcquireMountAndPath(path, &mnt, &rel);
+  if (error) {
+    errno = error;
+    return -1;
+  }
 
-  Mount* mnt = AcquireMountAndPath(path, &rel);
-  if (mnt == NULL) return -1;
-
-  MountNode* node = mnt->OpenResource(rel);
-  if (node == NULL) {
-    node = mnt->Open(rel, O_RDONLY);
-    if (node == NULL) {
+  MountNode* node = NULL;
+  error = mnt->OpenResource(rel, &node);
+  if (error) {
+    // OpenResource failed, try Open().
+    error = mnt->Open(rel, O_RDONLY, &node);
+    if (error) {
+      errno = error;
       ReleaseMount(mnt);
       return -1;
     }
   }
 
-  // OpenResource failed, try Open().
+  KernelHandle* handle = new KernelHandle(mnt, node);
+  error = handle->Init(O_RDONLY);
+  if (error) {
+    errno = error;
+    ReleaseMount(mnt);
+    return -1;
+  }
 
-  KernelHandle* handle = new KernelHandle(mnt, node, O_RDONLY);
   int fd = AllocateFD(handle);
   mnt->AcquireNode(node);
 
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h
index 6c7b6b31e9..e8c251a32a 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_proxy.h
@@ -24,9 +24,12 @@ class PepperInterface;
 
 // KernelProxy provide one-to-one mapping for libc kernel calls.  Calls to the
 // proxy will result in IO access to the provided Mount and MountNode objects.
+//
+// NOTE: The KernelProxy is the only class that should be setting errno. All
+// other classes should return Error (as defined by nacl_io/error.h).
 class KernelProxy : protected KernelObject {
  public:
-  typedef Mount* (*MountFactory_t)(int, StringMap_t&, PepperInterface*);
+  typedef Error (*MountFactory_t)(int, StringMap_t&, PepperInterface*, Mount**);
   typedef std::map<std::string, std::string> StringMap_t;
   typedef std::map<std::string, MountFactory_t> MountFactoryMap_t;
 
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_wrap.h b/native_client_sdk/src/libraries/nacl_io/kernel_wrap.h
index 87dca82eea..322fe72154 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_wrap.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_wrap.h
@@ -7,7 +7,7 @@
 
 #include <sys/types.h>
 #include <stdlib.h>
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 #if defined(__GLIBC__)
 #include <sys/cdefs.h>
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_real.h b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_real.h
index 7d7dd418c0..c4ff5e0e94 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_real.h
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_real.h
@@ -6,7 +6,7 @@
 #define LIBRARIES_NACL_IO_KERNEL_WRAP_REAL_H_
 
 #include "nacl_io/ostypes.h"
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 EXTERN_C_BEGIN
 
diff --git a/native_client_sdk/src/libraries/nacl_io/library.dsc b/native_client_sdk/src/libraries/nacl_io/library.dsc
index 2954618a57..81d621cfa2 100644
--- a/native_client_sdk/src/libraries/nacl_io/library.dsc
+++ b/native_client_sdk/src/libraries/nacl_io/library.dsc
@@ -2,8 +2,7 @@
   'TOOLS': ['newlib', 'glibc', 'pnacl', 'win'],
   'SEARCH': [
     '.',
-    'pepper',
-    '../utils'
+    'pepper'
   ],
   'TARGETS': [
     {
@@ -25,6 +24,7 @@
         "mount_node.cc",
         "mount_node_dir.cc",
         "mount_node_html5fs.cc",
+        "mount_node_http.cc",
         "mount_node_mem.cc",
         "mount_passthrough.cc",
         "nacl_io.cc",
@@ -37,6 +37,7 @@
   'HEADERS': [
     {
       'FILES': [
+        "error.h",
         "inode_pool.h",
         "kernel_handle.h",
         "kernel_intercept.h",
@@ -52,6 +53,7 @@
         "mount_node_dir.h",
         "mount_node.h",
         "mount_node_html5fs.h",
+        "mount_node_http.h",
         "mount_node_mem.h",
         "mount_passthrough.h",
         "nacl_io.h",
@@ -73,14 +75,6 @@
         "undef_macros.h",
       ],
       'DEST': 'include/nacl_io/pepper',
-    },
-    {
-      'FILES': [
-        "auto_lock.h",
-        "macros.h",
-        "ref_object.h"
-      ],
-      'DEST': 'include/utils',
     }
   ],
   'DEST': 'src',
diff --git a/native_client_sdk/src/libraries/nacl_io/mount.cc b/native_client_sdk/src/libraries/nacl_io/mount.cc
index 8b583db6fa..76fe3a7848 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount.cc
@@ -13,23 +13,21 @@
 #include "nacl_io/mount_node_mem.h"
 #include "nacl_io/osstat.h"
 #include "nacl_io/path.h"
-#include "utils/auto_lock.h"
-#include "utils/ref_object.h"
+#include "sdk_util/auto_lock.h"
+#include "sdk_util/ref_object.h"
 
 #if defined(WIN32)
 #include <windows.h>
 #endif
 
-Mount::Mount()
-  : dev_(0) {
-}
+Mount::Mount() : dev_(0) {}
 
 Mount::~Mount() {}
 
-bool Mount::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
+Error Mount::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
   dev_ = dev;
   ppapi_ = ppapi;
-  return true;
+  return 0;
 }
 
 void Mount::Destroy() {}
@@ -44,22 +42,30 @@ void Mount::ReleaseNode(MountNode* node) {
   node->Release();
 }
 
+Error Mount::OpenResource(const Path& path, MountNode** out_node) {
+  *out_node = NULL;
+  return EINVAL;
+}
+
 int Mount::OpenModeToPermission(int mode) {
   int out;
   switch (mode & 3) {
-    case O_RDONLY: out = S_IREAD;
-    case O_WRONLY: out = S_IWRITE;
-    case O_RDWR: out = S_IREAD | S_IWRITE;
+    case O_RDONLY:
+      out = S_IREAD;
+    case O_WRONLY:
+      out = S_IWRITE;
+    case O_RDWR:
+      out = S_IREAD | S_IWRITE;
   }
   return out;
 }
 
-
 void Mount::OnNodeCreated(MountNode* node) {
   node->stat_.st_ino = inode_pool_.Acquire();
   node->stat_.st_dev = dev_;
 }
 
 void Mount::OnNodeDestroyed(MountNode* node) {
-  if (node->stat_.st_ino) inode_pool_.Release(node->stat_.st_ino);
-}
\ No newline at end of file
+  if (node->stat_.st_ino)
+    inode_pool_.Release(node->stat_.st_ino);
+}
diff --git a/native_client_sdk/src/libraries/nacl_io/mount.h b/native_client_sdk/src/libraries/nacl_io/mount.h
index 622dae0207..ddf1fd5c76 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount.h
@@ -8,18 +8,20 @@
 #include <map>
 #include <string>
 
+#include "nacl_io/error.h"
 #include "nacl_io/inode_pool.h"
 #include "nacl_io/mount_node.h"
 #include "nacl_io/path.h"
-#include "utils/macros.h"
-#include "utils/ref_object.h"
+#include "sdk_util/macros.h"
+#include "sdk_util/ref_object.h"
 
 class MountNode;
 class PepperInterface;
 
 typedef std::map<std::string, std::string> StringMap_t;
 
-
+// NOTE: The KernelProxy is the only class that should be setting errno. All
+// other classes should return Error (as defined by nacl_io/error.h).
 class Mount : public RefObject {
  protected:
   // The protected functions are only used internally and will not
@@ -30,38 +32,49 @@ class Mount : public RefObject {
   // Init must be called by the factory before the mount is used.
   // This function must assign a root node, or replace FindNode.
   // |ppapi| can be NULL. If so, this mount cannot make any pepper calls.
-  virtual bool Init(int dev, StringMap_t& args, PepperInterface* ppapi);
+  virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi);
   virtual void Destroy();
 
  public:
   template <class M>
-  static Mount* Create(int dev, StringMap_t& args, PepperInterface* ppapi);
+  // Assumes that |out_mount| is non-NULL.
+  static Error Create(int dev,
+                      StringMap_t& args,
+                      PepperInterface* ppapi,
+                      Mount** out_mount);
 
   PepperInterface* ppapi() { return ppapi_; }
 
-  // All paths are expected to containing a leading "/"
+  // Assumes that |node| is non-NULL.
   void AcquireNode(MountNode* node);
+  // Assumes that |node| is non-NULL.
   void ReleaseNode(MountNode* node);
 
+  // All paths in functions below are expected to containing a leading "/".
+
   // Open a node at |path| with the specified open flags. The resulting
   // MountNode is created with a ref count of 1.
-  virtual MountNode *Open(const Path& path, int o_flags) = 0;
+  // Assumes that |out_node| is non-NULL.
+  virtual Error Open(const Path& path, int o_flags, MountNode** out_node) = 0;
 
   // OpenResource is only used to read files from the NaCl NMF file. No mount
   // except MountPassthrough should implement it.
-  virtual MountNode *OpenResource(const Path& path) { return NULL; }
+  // Assumes that |out_node| is non-NULL.
+  virtual Error OpenResource(const Path& path, MountNode** out_node);
 
   // Unlink, Mkdir, Rmdir will affect the both the RefCount
   // and the nlink number in the stat object.
-  virtual int Unlink(const Path& path) = 0;
-  virtual int Mkdir(const Path& path, int permissions) = 0;
-  virtual int Rmdir(const Path& path) = 0;
-  virtual int Remove(const Path& path) = 0;
+  virtual Error Unlink(const Path& path) = 0;
+  virtual Error Mkdir(const Path& path, int permissions) = 0;
+  virtual Error Rmdir(const Path& path) = 0;
+  virtual Error Remove(const Path& path) = 0;
 
   // Convert from R,W,R/W open flags to STAT permission flags
   static int OpenModeToPermission(int mode);
 
-  void OnNodeCreated(MountNode* node) ;
+  // Assumes that |node| is non-NULL.
+  void OnNodeCreated(MountNode* node);
+  // Assumes that |node| is non-NULL.
   void OnNodeDestroyed(MountNode* node);
 
  protected:
@@ -81,16 +94,22 @@ class Mount : public RefObject {
   DISALLOW_COPY_AND_ASSIGN(Mount);
 };
 
-
-template <class M>
 /*static*/
-Mount* Mount::Create(int dev, StringMap_t& args, PepperInterface* ppapi) {
+template <class M>
+Error Mount::Create(int dev,
+                    StringMap_t& args,
+                    PepperInterface* ppapi,
+                    Mount** out_mount) {
   Mount* mnt = new M();
-  if (mnt->Init(dev, args, ppapi) == false) {
+  Error error = mnt->Init(dev, args, ppapi);
+  if (error) {
     delete mnt;
-    return NULL;
+    *out_mount = NULL;
+    return error;
   }
-  return mnt;
+
+  *out_mount = mnt;
+  return 0;
 }
 
 #endif  // LIBRARIES_NACL_IO_MOUNT_H_
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_dev.cc b/native_client_sdk/src/libraries/nacl_io/mount_dev.cc
index 83d2e55423..11893ea09e 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_dev.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_dev.cc
@@ -14,31 +14,26 @@
 #include "nacl_io/mount_node.h"
 #include "nacl_io/mount_node_dir.h"
 #include "nacl_io/pepper_interface.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
 
 #if defined(__native_client__)
-#  include <irt.h>
+#include <irt.h>
 #elif defined(WIN32)
-#  include <stdlib.h>
+#include <stdlib.h>
 #endif
 
-
 namespace {
 
-void ReleaseAndNullNode(MountNode** node) {
-  if (*node)
-    (*node)->Release();
-  *node = NULL;
-}
-
-
 class RealNode : public MountNode {
  public:
   RealNode(Mount* mount, int fd);
 
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int Write(size_t offs, const void* buf, size_t count);
-  virtual int GetStat(struct stat* stat);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
+  virtual Error GetStat(struct stat* stat);
 
  protected:
   int fd_;
@@ -48,43 +43,56 @@ class NullNode : public MountNode {
  public:
   explicit NullNode(Mount* mount);
 
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int Write(size_t offs, const void* buf, size_t count);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
 };
 
 class ConsoleNode : public NullNode {
  public:
   ConsoleNode(Mount* mount, PP_LogLevel level);
 
-  virtual int Write(size_t offs, const void* buf, size_t count);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
 
-private:
+ private:
   PP_LogLevel level_;
 };
 
-
 class TtyNode : public NullNode {
  public:
   explicit TtyNode(Mount* mount);
 
-  virtual int Write(size_t offs, const void* buf, size_t count);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
 };
 
-
 class ZeroNode : public MountNode {
  public:
   explicit ZeroNode(Mount* mount);
 
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int Write(size_t offs, const void* buf, size_t count);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
 };
 
 class UrandomNode : public MountNode {
  public:
   explicit UrandomNode(Mount* mount);
 
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int Write(size_t offs, const void* buf, size_t count);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
 
  private:
 #if defined(__native_client__)
@@ -93,132 +101,141 @@ class UrandomNode : public MountNode {
 #endif
 };
 
-RealNode::RealNode(Mount* mount, int fd)
-    : MountNode(mount),
-      fd_(fd) {
+RealNode::RealNode(Mount* mount, int fd) : MountNode(mount), fd_(fd) {
   stat_.st_mode = S_IFCHR;
 }
 
-int RealNode::Read(size_t offs, void* buf, size_t count) {
+Error RealNode::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
+  *out_bytes = 0;
+
   size_t readcnt;
   int err = _real_read(fd_, buf, count, &readcnt);
-  if (err) {
-    errno = err;
-    return -1;
-  }
-  return static_cast<int>(readcnt);
+  if (err)
+    return err;
+
+  *out_bytes = static_cast<int>(readcnt);
+  return 0;
 }
 
-int RealNode::Write(size_t offs, const void* buf, size_t count) {
+Error RealNode::Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes) {
+  *out_bytes = 0;
+
   size_t writecnt;
   int err = _real_write(fd_, buf, count, &writecnt);
-  if (err) {
-    errno = err;
-    return -1;
-  }
-  return static_cast<int>(writecnt);
-}
+  if (err)
+    return err;
 
-int RealNode::GetStat(struct stat* stat) {
-  int err =  _real_fstat(fd_, stat);
-  if (err) {
-    errno = err;
-    return -1;
-  }
+  *out_bytes = static_cast<int>(writecnt);
   return 0;
 }
 
-NullNode::NullNode(Mount* mount)
-    : MountNode(mount) {
-  stat_.st_mode = S_IFCHR;
-}
+Error RealNode::GetStat(struct stat* stat) { return _real_fstat(fd_, stat); }
 
-int NullNode::Read(size_t offs, void* buf, size_t count) {
+NullNode::NullNode(Mount* mount) : MountNode(mount) { stat_.st_mode = S_IFCHR; }
+
+Error NullNode::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
+  *out_bytes = 0;
   return 0;
 }
 
-int NullNode::Write(size_t offs, const void* buf, size_t count) {
-  return count;
+Error NullNode::Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes) {
+  *out_bytes = count;
+  return 0;
 }
 
 ConsoleNode::ConsoleNode(Mount* mount, PP_LogLevel level)
-    : NullNode(mount),
-    level_(level) {
+    : NullNode(mount), level_(level) {
   stat_.st_mode = S_IFCHR;
 }
 
-int ConsoleNode::Write(size_t offs, const void* buf, size_t count) {
+Error ConsoleNode::Write(size_t offs,
+                         const void* buf,
+                         size_t count,
+                         int* out_bytes) {
+  *out_bytes = 0;
+
   ConsoleInterface* con_intr = mount_->ppapi()->GetConsoleInterface();
   VarInterface* var_intr = mount_->ppapi()->GetVarInterface();
 
-  if (var_intr && con_intr) {
-    const char* data = static_cast<const char *>(buf);
-    uint32_t len = static_cast<uint32_t>(count);
-    struct PP_Var val = var_intr->VarFromUtf8(data, len);
-    con_intr->Log(mount_->ppapi()->GetInstance(), level_, val);
-    return count;
-  }
+  if (!(var_intr && con_intr))
+    return ENOSYS;
+
+  const char* data = static_cast<const char*>(buf);
+  uint32_t len = static_cast<uint32_t>(count);
+  struct PP_Var val = var_intr->VarFromUtf8(data, len);
+  con_intr->Log(mount_->ppapi()->GetInstance(), level_, val);
+
+  *out_bytes = count;
   return 0;
 }
 
+TtyNode::TtyNode(Mount* mount) : NullNode(mount) {}
 
-TtyNode::TtyNode(Mount* mount)
-    : NullNode(mount) {
-}
+Error TtyNode::Write(size_t offs,
+                     const void* buf,
+                     size_t count,
+                     int* out_bytes) {
+  *out_bytes = 0;
 
-int TtyNode::Write(size_t offs, const void* buf, size_t count) {
   MessagingInterface* msg_intr = mount_->ppapi()->GetMessagingInterface();
   VarInterface* var_intr = mount_->ppapi()->GetVarInterface();
 
-  if (var_intr && msg_intr) {
-    const char* data = static_cast<const char *>(buf);
-    uint32_t len = static_cast<uint32_t>(count);
-    struct PP_Var val = var_intr->VarFromUtf8(data, len);
-    msg_intr->PostMessage(mount_->ppapi()->GetInstance(), val);
-    return count;
-  }
-  return 0;
-}
+  if (!(var_intr && msg_intr))
+    return ENOSYS;
 
+  const char* data = static_cast<const char*>(buf);
+  uint32_t len = static_cast<uint32_t>(count);
+  struct PP_Var val = var_intr->VarFromUtf8(data, len);
+  msg_intr->PostMessage(mount_->ppapi()->GetInstance(), val);
 
-ZeroNode::ZeroNode(Mount* mount)
-    : MountNode(mount) {
-  stat_.st_mode = S_IFCHR;
+  *out_bytes = count;
+  return 0;
 }
 
-int ZeroNode::Read(size_t offs, void* buf, size_t count) {
+ZeroNode::ZeroNode(Mount* mount) : MountNode(mount) { stat_.st_mode = S_IFCHR; }
+
+Error ZeroNode::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
   memset(buf, 0, count);
-  return count;
+  *out_bytes = count;
+  return 0;
 }
 
-int ZeroNode::Write(size_t offs, const void* buf, size_t count) {
-  return count;
+Error ZeroNode::Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes) {
+  *out_bytes = count;
+  return 0;
 }
 
-UrandomNode::UrandomNode(Mount* mount)
-    : MountNode(mount) {
+UrandomNode::UrandomNode(Mount* mount) : MountNode(mount) {
   stat_.st_mode = S_IFCHR;
 #if defined(__native_client__)
-  size_t result = nacl_interface_query(NACL_IRT_RANDOM_v0_1, &random_interface_,
-                                       sizeof(random_interface_));
+  size_t result = nacl_interface_query(
+      NACL_IRT_RANDOM_v0_1, &random_interface_, sizeof(random_interface_));
   interface_ok_ = result != 0;
 #endif
 }
 
-int UrandomNode::Read(size_t offs, void* buf, size_t count) {
+Error UrandomNode::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
+  *out_bytes = 0;
+
 #if defined(__native_client__)
-  if (interface_ok_) {
-    size_t nread;
-    int result = (*random_interface_.get_random_bytes)(buf, count, &nread);
-    if (result != 0) {
-      errno = result;
-      return 0;
-    }
+  if (!interface_ok_)
+    return EBADF;
 
-    return count;
-  }
+  size_t nread;
+  int error = (*random_interface_.get_random_bytes)(buf, count, &nread);
+  if (error)
+    return error;
 
-  errno = EBADF;
+  *out_bytes = count;
   return 0;
 #elif defined(WIN32)
   char* out = static_cast<char*>(buf);
@@ -227,8 +244,8 @@ int UrandomNode::Read(size_t offs, void* buf, size_t count) {
     unsigned int random_int;
     errno_t err = rand_s(&random_int);
     if (err) {
-      errno = err;
-      return count - bytes_left;
+      *out_bytes = count - bytes_left;
+      return err;
     }
 
     int bytes_to_copy = std::min(bytes_left, sizeof(random_int));
@@ -237,107 +254,84 @@ int UrandomNode::Read(size_t offs, void* buf, size_t count) {
     bytes_left -= bytes_to_copy;
   }
 
-  return count;
+  *out_bytes = count;
+  return 0;
 #endif
 }
 
-int UrandomNode::Write(size_t offs, const void* buf, size_t count) {
-  return count;
+Error UrandomNode::Write(size_t offs,
+                         const void* buf,
+                         size_t count,
+                         int* out_bytes) {
+  *out_bytes = count;
+  return 0;
 }
 
-
-
 }  // namespace
 
-MountNode *MountDev::Open(const Path& path, int mode) {
+Error MountDev::Open(const Path& path, int mode, MountNode** out_node) {
+  *out_node = NULL;
+
   AutoLock lock(&lock_);
 
   // Don't allow creating any files.
   if (mode & O_CREAT)
-    return NULL;
+    return EINVAL;
 
-  MountNode* node = root_->FindChild(path.Join());
-  if (node)
-    node->Acquire();
-  return node;
-}
+  MountNode* node = NULL;
+  int error = root_->FindChild(path.Join(), &node);
+  if (error)
+    return error;
 
-int MountDev::Unlink(const Path& path) {
-  errno = EINVAL;
-  return -1;
+  node->Acquire();
+  *out_node = node;
+  return 0;
 }
 
-int MountDev::Mkdir(const Path& path, int permissions) {
-  errno = EINVAL;
-  return -1;
-}
+Error MountDev::Unlink(const Path& path) { return EINVAL; }
 
-int MountDev::Rmdir(const Path& path) {
-  errno = EINVAL;
-  return -1;
-}
+Error MountDev::Mkdir(const Path& path, int permissions) { return EINVAL; }
 
-int MountDev::Remove(const Path& path) {
-  errno = EINVAL;
-  return -1;
-}
+Error MountDev::Rmdir(const Path& path) { return EINVAL; }
 
-MountDev::MountDev()
-    : null_node_(NULL),
-      zero_node_(NULL),
-      random_node_(NULL),
-      console0_node_(NULL),
-      console1_node_(NULL),
-      console2_node_(NULL),
-      console3_node_(NULL),
-      tty_node_(NULL) {
-}
+Error MountDev::Remove(const Path& path) { return EINVAL; }
 
-bool MountDev::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
-  if (!Mount::Init(dev, args, ppapi))
-    return false;
+MountDev::MountDev() {}
+
+#define INITIALIZE_DEV_NODE(path, klass)          \
+  error = root_->AddChild(path, new klass(this)); \
+  if (error)                                      \
+    return error;
+
+#define INITIALIZE_DEV_NODE_1(path, klass, arg)        \
+  error = root_->AddChild(path, new klass(this, arg)); \
+  if (error)                                           \
+    return error;
+
+Error MountDev::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
+  Error error = Mount::Init(dev, args, ppapi);
+  if (error)
+    return error;
 
   root_ = new MountNodeDir(this);
-  null_node_ = new NullNode(this);
-  root_->AddChild("/null", null_node_);
-  zero_node_ = new ZeroNode(this);
-  root_->AddChild("/zero", zero_node_);
-  random_node_ = new UrandomNode(this);
-  root_->AddChild("/urandom", random_node_);
-
-  console0_node_ = new ConsoleNode(this, PP_LOGLEVEL_TIP);
-  root_->AddChild("/console0", console0_node_);
-  console1_node_ = new ConsoleNode(this, PP_LOGLEVEL_LOG);
-  root_->AddChild("/console1", console1_node_);
-  console2_node_ = new ConsoleNode(this, PP_LOGLEVEL_WARNING);
-  root_->AddChild("/console2", console2_node_);
-  console3_node_ = new ConsoleNode(this, PP_LOGLEVEL_ERROR);
-  root_->AddChild("/console3", console3_node_);
-
-  tty_node_ = new TtyNode(this);
-  root_->AddChild("/tty", tty_node_);
-
-  stdin_node_ = new RealNode(this, 0);
-  root_->AddChild("/stdin", stdin_node_);
-  stdout_node_ = new RealNode(this, 1);
-  root_->AddChild("/stdout", stdout_node_);
-  stderr_node_ = new RealNode(this, 2);
-  root_->AddChild("/stderr", stderr_node_);
-
-  return true;
+
+  INITIALIZE_DEV_NODE("/null", NullNode);
+  INITIALIZE_DEV_NODE("/zero", ZeroNode);
+  INITIALIZE_DEV_NODE("/urandom", UrandomNode);
+  INITIALIZE_DEV_NODE_1("/console0", ConsoleNode, PP_LOGLEVEL_TIP);
+  INITIALIZE_DEV_NODE_1("/console1", ConsoleNode, PP_LOGLEVEL_LOG);
+  INITIALIZE_DEV_NODE_1("/console2", ConsoleNode, PP_LOGLEVEL_WARNING);
+  INITIALIZE_DEV_NODE_1("/console3", ConsoleNode, PP_LOGLEVEL_ERROR);
+  INITIALIZE_DEV_NODE("/tty", TtyNode);
+  INITIALIZE_DEV_NODE_1("/stdin", RealNode, 0);
+  INITIALIZE_DEV_NODE_1("/stdout", RealNode, 1);
+  INITIALIZE_DEV_NODE_1("/stderr", RealNode, 2);
+
+  return 0;
 }
 
 void MountDev::Destroy() {
-  ReleaseAndNullNode(&stdin_node_);
-  ReleaseAndNullNode(&stdout_node_);
-  ReleaseAndNullNode(&stderr_node_);
-  ReleaseAndNullNode(&tty_node_);
-  ReleaseAndNullNode(&console3_node_);
-  ReleaseAndNullNode(&console2_node_);
-  ReleaseAndNullNode(&console1_node_);
-  ReleaseAndNullNode(&console0_node_);
-  ReleaseAndNullNode(&random_node_);
-  ReleaseAndNullNode(&zero_node_);
-  ReleaseAndNullNode(&null_node_);
-  ReleaseAndNullNode(&root_);
+  if (root_)
+    root_->Release();
+  root_ = NULL;
 }
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_dev.h b/native_client_sdk/src/libraries/nacl_io/mount_dev.h
index ff3d99c124..7ad7daa3b9 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_dev.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_dev.h
@@ -11,32 +11,21 @@ class MountNode;
 
 class MountDev : public Mount {
  public:
-  virtual MountNode *Open(const Path& path, int mode);
+  virtual Error Open(const Path& path, int mode, MountNode** out_node);
 
-  virtual int Unlink(const Path& path);
-  virtual int Mkdir(const Path& path, int permissions);
-  virtual int Rmdir(const Path& path);
-  virtual int Remove(const Path& path);
+  virtual Error Unlink(const Path& path);
+  virtual Error Mkdir(const Path& path, int permissions);
+  virtual Error Rmdir(const Path& path);
+  virtual Error Remove(const Path& path);
 
  protected:
   MountDev();
 
-  virtual bool Init(int dev, StringMap_t& args, PepperInterface* ppapi);
+  virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi);
   virtual void Destroy();
 
  private:
   MountNode* root_;
-  MountNode* null_node_;
-  MountNode* zero_node_;
-  MountNode* random_node_;
-  MountNode* console0_node_;
-  MountNode* console1_node_;
-  MountNode* console2_node_;
-  MountNode* console3_node_;
-  MountNode* tty_node_;
-  MountNode* stderr_node_;
-  MountNode* stdin_node_;
-  MountNode* stdout_node_;
 
   friend class Mount;
 };
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_html5fs.cc b/native_client_sdk/src/libraries/nacl_io/mount_html5fs.cc
index 9b995359ae..0008284253 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_html5fs.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_html5fs.cc
@@ -12,7 +12,7 @@
 #include <string.h>
 #include <algorithm>
 #include "nacl_io/mount_node_html5fs.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
 
 namespace {
 
@@ -24,96 +24,85 @@ int64_t strtoull(const char* nptr, char** endptr, int base) {
 
 }  // namespace
 
-MountNode *MountHtml5Fs::Open(const Path& path, int mode) {
-  if (BlockUntilFilesystemOpen() != PP_OK) {
-    errno = ENODEV;
-    return NULL;
-  }
+Error MountHtml5Fs::Open(const Path& path, int mode, MountNode** out_node) {
+  *out_node = NULL;
+
+  Error error = BlockUntilFilesystemOpen();
+  if (error)
+    return error;
 
-  PP_Resource fileref = ppapi()->GetFileRefInterface()->Create(
-      filesystem_resource_, path.Join().c_str());
+  PP_Resource fileref = ppapi()->GetFileRefInterface()
+      ->Create(filesystem_resource_, path.Join().c_str());
   if (!fileref)
-    return NULL;
+    return ENOSYS;
 
   MountNodeHtml5Fs* node = new MountNodeHtml5Fs(this, fileref);
-  if (!node->Init(mode)) {
+  error = node->Init(mode);
+  if (error) {
     node->Release();
-    return NULL;
+    return error;
   }
 
-  return node;
+  *out_node = node;
+  return 0;
 }
 
-int MountHtml5Fs::Unlink(const Path& path) {
-  return Remove(path);
-}
+Error MountHtml5Fs::Unlink(const Path& path) { return Remove(path); }
 
-int MountHtml5Fs::Mkdir(const Path& path, int permissions) {
-  if (BlockUntilFilesystemOpen() != PP_OK) {
-    errno = ENODEV;
-    return -1;
-  }
+Error MountHtml5Fs::Mkdir(const Path& path, int permissions) {
+  Error error = BlockUntilFilesystemOpen();
+  if (error)
+    return error;
 
   ScopedResource fileref_resource(
-      ppapi(), ppapi()->GetFileRefInterface()->Create(filesystem_resource_,
-                                                      path.Join().c_str()));
-  if (!fileref_resource.pp_resource()) {
-    errno = EINVAL;
-    return -1;
-  }
+      ppapi(),
+      ppapi()->GetFileRefInterface()->Create(filesystem_resource_,
+                                             path.Join().c_str()));
+  if (!fileref_resource.pp_resource())
+    return EIO;
 
   int32_t result = ppapi()->GetFileRefInterface()->MakeDirectory(
       fileref_resource.pp_resource(), PP_FALSE, PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
 
   return 0;
 }
 
-int MountHtml5Fs::Rmdir(const Path& path) {
-  return Remove(path);
-}
+Error MountHtml5Fs::Rmdir(const Path& path) { return Remove(path); }
 
-int MountHtml5Fs::Remove(const Path& path) {
-  if (BlockUntilFilesystemOpen() != PP_OK) {
-    errno = ENODEV;
-    return -1;
-  }
+Error MountHtml5Fs::Remove(const Path& path) {
+  Error error = BlockUntilFilesystemOpen();
+  if (error)
+    return error;
 
   ScopedResource fileref_resource(
-      ppapi(), ppapi()->GetFileRefInterface()->Create(filesystem_resource_,
-                                                      path.Join().c_str()));
-  if (!fileref_resource.pp_resource()) {
-    errno = EINVAL;
-    return -1;
-  }
+      ppapi(),
+      ppapi()->GetFileRefInterface()->Create(filesystem_resource_,
+                                             path.Join().c_str()));
+  if (!fileref_resource.pp_resource())
+    return ENOSYS;
 
-  int32_t result = ppapi()->GetFileRefInterface()->Delete(
-      fileref_resource.pp_resource(),
-      PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+  int32_t result = ppapi()->GetFileRefInterface()
+      ->Delete(fileref_resource.pp_resource(), PP_BlockUntilComplete());
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
 
   return 0;
 }
 
-
 MountHtml5Fs::MountHtml5Fs()
     : filesystem_resource_(0),
       filesystem_open_has_result_(false),
-      filesystem_open_result_(PP_OK) {
-}
+      filesystem_open_error_(0) {}
 
-bool MountHtml5Fs::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
-  if (!Mount::Init(dev, args, ppapi))
-    return false;
+Error MountHtml5Fs::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
+  Error error = Mount::Init(dev, args, ppapi);
+  if (error)
+    return error;
 
   if (!ppapi)
-    return false;
+    return ENOSYS;
 
   pthread_cond_init(&filesystem_open_cond_, NULL);
 
@@ -121,7 +110,7 @@ bool MountHtml5Fs::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
   PP_FileSystemType filesystem_type = PP_FILESYSTEMTYPE_LOCALPERSISTENT;
   int64_t expected_size = 0;
   for (StringMap_t::iterator iter = args.begin(), end = args.end(); iter != end;
-      ++iter) {
+       ++iter) {
     if (iter->first == "type") {
       if (iter->second == "PERSISTENT") {
         filesystem_type = PP_FILESYSTEMTYPE_LOCALPERSISTENT;
@@ -134,33 +123,32 @@ bool MountHtml5Fs::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
   }
 
   // Initialize filesystem.
-  filesystem_resource_ = ppapi->GetFileSystemInterface()->Create(
-      ppapi_->GetInstance(), filesystem_type);
-
+  filesystem_resource_ = ppapi->GetFileSystemInterface()
+      ->Create(ppapi_->GetInstance(), filesystem_type);
   if (filesystem_resource_ == 0)
-    return false;
+    return ENOSYS;
 
   // We can't block the main thread, so make an asynchronous call if on main
   // thread. If we are off-main-thread, then don't make an asynchronous call;
   // otherwise we require a message loop.
   bool main_thread = ppapi->IsMainThread();
-  PP_CompletionCallback cc = main_thread ?
-      PP_MakeCompletionCallback(&MountHtml5Fs::FilesystemOpenCallbackThunk,
-                                this) :
-      PP_BlockUntilComplete();
+  PP_CompletionCallback cc =
+      main_thread ? PP_MakeCompletionCallback(
+                        &MountHtml5Fs::FilesystemOpenCallbackThunk, this)
+                  : PP_BlockUntilComplete();
 
-  int32_t result = ppapi->GetFileSystemInterface()->Open(
-      filesystem_resource_, expected_size, cc);
+  int32_t result = ppapi->GetFileSystemInterface()
+      ->Open(filesystem_resource_, expected_size, cc);
 
   if (!main_thread) {
     filesystem_open_has_result_ = true;
-    filesystem_open_result_ = result;
+    filesystem_open_error_ = PPErrorToErrno(result);
 
-    return filesystem_open_result_ == PP_OK;
+    return filesystem_open_error_;
   } else {
     // We have to assume the call to Open will succeed; there is no better
     // result to return here.
-    return true;
+    return 0;
   }
 }
 
@@ -169,12 +157,12 @@ void MountHtml5Fs::Destroy() {
   pthread_cond_destroy(&filesystem_open_cond_);
 }
 
-int32_t MountHtml5Fs::BlockUntilFilesystemOpen() {
+Error MountHtml5Fs::BlockUntilFilesystemOpen() {
   AutoLock lock(&lock_);
   while (!filesystem_open_has_result_) {
     pthread_cond_wait(&filesystem_open_cond_, &lock_);
   }
-  return filesystem_open_result_;
+  return filesystem_open_error_;
 }
 
 // static
@@ -187,6 +175,6 @@ void MountHtml5Fs::FilesystemOpenCallbackThunk(void* user_data,
 void MountHtml5Fs::FilesystemOpenCallback(int32_t result) {
   AutoLock lock(&lock_);
   filesystem_open_has_result_ = true;
-  filesystem_open_result_ = result;
+  filesystem_open_error_ = PPErrorToErrno(result);
   pthread_cond_signal(&filesystem_open_cond_);
 }
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h b/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h
index a6633be8af..e872dae353 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_html5fs.h
@@ -11,23 +11,23 @@
 
 class MountNode;
 
-class MountHtml5Fs: public Mount {
+class MountHtml5Fs : public Mount {
  public:
-  virtual MountNode *Open(const Path& path, int mode);
-  virtual int Unlink(const Path& path);
-  virtual int Mkdir(const Path& path, int permissions);
-  virtual int Rmdir(const Path& path);
-  virtual int Remove(const Path& path);
+  virtual Error Open(const Path& path, int mode, MountNode** out_node);
+  virtual Error Unlink(const Path& path);
+  virtual Error Mkdir(const Path& path, int permissions);
+  virtual Error Rmdir(const Path& path);
+  virtual Error Remove(const Path& path);
 
   PP_Resource filesystem_resource() { return filesystem_resource_; }
 
  protected:
   MountHtml5Fs();
 
-  virtual bool Init(int dev, StringMap_t& args, PepperInterface* ppapi);
+  virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi);
   virtual void Destroy();
 
-  int32_t BlockUntilFilesystemOpen();
+  Error BlockUntilFilesystemOpen();
 
  private:
   static void FilesystemOpenCallbackThunk(void* user_data, int32_t result);
@@ -35,7 +35,7 @@ class MountHtml5Fs: public Mount {
 
   PP_Resource filesystem_resource_;
   bool filesystem_open_has_result_;  // protected by lock_.
-  int32_t filesystem_open_result_;  // protected by lock_.
+  Error filesystem_open_error_;      // protected by lock_.
   pthread_cond_t filesystem_open_cond_;
 
   friend class Mount;
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_http.cc b/native_client_sdk/src/libraries/nacl_io/mount_http.cc
index 9a6579ed07..7b4316e842 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_http.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_http.cc
@@ -4,30 +4,30 @@
  */
 
 #include "nacl_io/mount_http.h"
+
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <ppapi/c/pp_errors.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+
 #include <vector>
-#include "nacl_io/mount_node_dir.h"
-#include "nacl_io/osinttypes.h"
-#include "utils/auto_lock.h"
 
-#if defined(WIN32)
-#define snprintf _snprintf
-#endif
+#include <ppapi/c/pp_errors.h>
 
+#include "nacl_io/mount_node_dir.h"
+#include "nacl_io/mount_node_http.h"
+#include "nacl_io/osinttypes.h"
+#include "sdk_util/auto_lock.h"
 
 namespace {
 
-typedef std::vector<char *> StringList_t;
-size_t SplitString(char *str, const char *delim, StringList_t* list) {
-  char *item = strtok(str, delim);
+typedef std::vector<char*> StringList_t;
+size_t SplitString(char* str, const char* delim, StringList_t* list) {
+  char* item = strtok(str, delim);
 
   list->clear();
   while (item) {
@@ -38,13 +38,7 @@ size_t SplitString(char *str, const char *delim, StringList_t* list) {
   return list->size();
 }
 
-
-// If we're attempting to read a partial request, but the server returns a full
-// request, we need to read all of the data up to the start of our partial
-// request into a dummy buffer. This is the maximum size of that buffer.
-const size_t MAX_READ_BUFFER_SIZE = 64 * 1024;
-const int32_t STATUSCODE_OK = 200;
-const int32_t STATUSCODE_PARTIAL_CONTENT = 206;
+}  // namespace
 
 std::string NormalizeHeaderKey(const std::string& s) {
   // Capitalize the first letter and any letter following a hyphen:
@@ -60,557 +54,64 @@ std::string NormalizeHeaderKey(const std::string& s) {
   return result;
 }
 
-StringMap_t ParseHeaders(const char* headers, int32_t headers_length) {
-  enum State {
-    FINDING_KEY,
-    SKIPPING_WHITESPACE,
-    FINDING_VALUE,
-  };
-
-  StringMap_t result;
-  std::string key;
-  std::string value;
-
-  State state = FINDING_KEY;
-  const char* start = headers;
-  for (int i = 0; i < headers_length; ++i) {
-    switch (state) {
-      case FINDING_KEY:
-        if (headers[i] == ':') {
-          // Found key.
-          key.assign(start, &headers[i] - start);
-          key = NormalizeHeaderKey(key);
-          state = SKIPPING_WHITESPACE;
-        }
-        break;
-
-      case SKIPPING_WHITESPACE:
-        if (headers[i] == ' ') {
-          // Found whitespace, keep going...
-          break;
-        }
-
-        // Found a non-whitespace, mark this as the start of the value.
-        start = &headers[i];
-        state = FINDING_VALUE;
-        // Fallthrough to start processing value without incrementing i.
-
-      case FINDING_VALUE:
-        if (headers[i] == '\n') {
-          // Found value.
-          value.assign(start, &headers[i] - start);
-          result[key] = value;
-          start = &headers[i + 1];
-          state = FINDING_KEY;
-        }
-        break;
-    }
-  }
-
-  return result;
-}
-
-bool ParseContentLength(const StringMap_t& headers, size_t* content_length) {
-  StringMap_t::const_iterator iter = headers.find("Content-Length");
-  if (iter == headers.end())
-    return false;
-
-  *content_length = strtoul(iter->second.c_str(), NULL, 10);
-  return true;
-}
-
-bool ParseContentRange(const StringMap_t& headers, size_t* read_start,
-                       size_t* read_end, size_t* entity_length) {
-  StringMap_t::const_iterator iter = headers.find("Content-Range");
-  if (iter == headers.end())
-    return false;
-
-  // The key should look like "bytes ##-##/##" or "bytes ##-##/*". The last
-  // value is the entity length, which can potentially be * (i.e. unknown).
-  int read_start_int;
-  int read_end_int;
-  int entity_length_int;
-  int result = sscanf(iter->second.c_str(), "bytes %"SCNuS"-%"SCNuS"/%"SCNuS,
-                      &read_start_int, &read_end_int, &entity_length_int);
-
-  // The Content-Range header specifies an inclusive range: e.g. the first ten
-  // bytes is "bytes 0-9/*". Convert it to a half-open range by incrementing
-  // read_end.
-  if (result == 2) {
-    *read_start = read_start_int;
-    *read_end = read_end_int + 1;
-    *entity_length = 0;
-    return true;
-  } else if (result == 3) {
-    *read_start = read_start_int;
-    *read_end = read_end_int + 1;
-    *entity_length = entity_length_int;
-    return true;
-  }
-
-  return false;
-}
-
-}  // namespace
-
-
-class MountNodeHttp : public MountNode {
- public:
-  virtual int FSync();
-  virtual int GetDents(size_t offs, struct dirent* pdir, size_t count);
-  virtual int GetStat(struct stat* stat);
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int FTruncate(off_t size);
-  virtual int Write(size_t offs, const void* buf, size_t count);
-  virtual size_t GetSize();
-
-  void SetCachedSize(off_t size);
-
- protected:
-  MountNodeHttp(Mount* mount, const std::string& url, bool cache_content);
-
- private:
-  bool OpenUrl(const char* method,
-               StringMap_t* request_headers,
-               PP_Resource* out_loader,
-               PP_Resource* out_request,
-               PP_Resource* out_response,
-               int32_t* out_statuscode,
-               StringMap_t* out_response_headers);
-
-  int DownloadToCache();
-  int ReadPartialFromCache(size_t offs, void* buf, size_t count);
-  int DownloadPartial(size_t offs, void* buf, size_t count);
-  int DownloadToBuffer(PP_Resource loader, void* buf, size_t count);
-
-  std::string url_;
-  std::vector<char> buffer_;
-
-  bool cache_content_;
-  bool has_cached_size_;
-  std::vector<char> cached_data_;
-
-  friend class MountHttp;
-};
-
-void MountNodeHttp::SetCachedSize(off_t size) {
-  has_cached_size_ = true;
-  stat_.st_size = size;
-}
-
-int MountNodeHttp::FSync() {
-  errno = ENOSYS;
-  return -1;
-}
-
-int MountNodeHttp::GetDents(size_t offs, struct dirent* pdir, size_t count) {
-  errno = ENOSYS;
-  return -1;
-}
-
-int MountNodeHttp::GetStat(struct stat* stat) {
-  AutoLock lock(&lock_);
-
-  // Assume we need to 'HEAD' if we do not know the size, otherwise, assume
-  // that the information is constant.  We can add a timeout if needed.
-  MountHttp* mount = static_cast<MountHttp*>(mount_);
-  if (stat_.st_size == 0 || !mount->cache_stat_) {
-    StringMap_t headers;
-    PP_Resource loader;
-    PP_Resource request;
-    PP_Resource response;
-    int32_t statuscode;
-    StringMap_t response_headers;
-    if (!OpenUrl("HEAD", &headers, &loader, &request, &response, &statuscode,
-                &response_headers)) {
-      // errno is already set by OpenUrl.
-      return -1;
-    }
-
-    ScopedResource scoped_loader(mount_->ppapi(), loader);
-    ScopedResource scoped_request(mount_->ppapi(), request);
-    ScopedResource scoped_response(mount_->ppapi(), response);
-
-
-    size_t entity_length;
-    if (ParseContentLength(response_headers, &entity_length)) {
-      SetCachedSize(static_cast<off_t>(entity_length));
-    } else if (cache_content_ && !has_cached_size_) {
-      DownloadToCache();
-    } else {
-      // Don't use SetCachedSize here -- it is actually unknown.
-      stat_.st_size = 0;
-    }
-
-    stat_.st_atime = 0; // TODO(binji): Use "Last-Modified".
-    stat_.st_mtime = 0;
-    stat_.st_ctime = 0;
-  }
-
-  // Fill the stat structure if provided
-  if (stat) {
-    memcpy(stat, &stat_, sizeof(stat_));
-  }
-  return 0;
-}
-
-int MountNodeHttp::Read(size_t offs, void* buf, size_t count) {
-  AutoLock lock(&lock_);
-  if (cache_content_) {
-    if (cached_data_.empty()) {
-      if (DownloadToCache() < 0)
-        return -1;
-    }
-
-    return ReadPartialFromCache(offs, buf, count);
-  }
-
-  return DownloadPartial(offs, buf, count);
-}
-
-int MountNodeHttp::FTruncate(off_t size) {
-  errno = ENOSYS;
-  return -1;
-}
-
-int MountNodeHttp::Write(size_t offs, const void* buf, size_t count) {
-  // TODO(binji): support POST?
-  errno = ENOSYS;
-  return -1;
-}
-
-size_t MountNodeHttp::GetSize() {
-  // TODO(binji): This value should be cached properly; i.e. obey the caching
-  // headers returned by the server.
-  AutoLock lock(&lock_);
-  if (!has_cached_size_) {
-    // Even if DownloadToCache fails, the best result we can return is what
-    // was written to stat_.st_size.
-    if (cache_content_)
-      DownloadToCache();
-  }
-
-  return stat_.st_size;
-}
-
-MountNodeHttp::MountNodeHttp(Mount* mount, const std::string& url,
-                             bool cache_content)
-    : MountNode(mount),
-      url_(url),
-      cache_content_(cache_content),
-      has_cached_size_(false) {
-}
-
-bool MountNodeHttp::OpenUrl(const char* method,
-                           StringMap_t* request_headers,
-                           PP_Resource* out_loader,
-                           PP_Resource* out_request,
-                           PP_Resource* out_response,
-                           int32_t* out_statuscode,
-                           StringMap_t* out_response_headers) {
-  // Assume lock_ is already held.
-
-  PepperInterface* ppapi = mount_->ppapi();
-
-  MountHttp* mount_http = static_cast<MountHttp*>(mount_);
-  ScopedResource request(ppapi,
-                         mount_http->MakeUrlRequestInfo(url_, method,
-                                                        request_headers));
-  if (!request.pp_resource()) {
-    errno = EINVAL;
-    return false;
-  }
-
-  URLLoaderInterface* loader_interface = ppapi->GetURLLoaderInterface();
-  URLResponseInfoInterface* response_interface =
-      ppapi->GetURLResponseInfoInterface();
-  VarInterface* var_interface = ppapi->GetVarInterface();
-
-  ScopedResource loader(ppapi, loader_interface->Create(ppapi->GetInstance()));
-  if (!loader.pp_resource()) {
-    errno = EINVAL;
-    return false;
-  }
-
-  int32_t result = loader_interface->Open(
-      loader.pp_resource(), request.pp_resource(), PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return false;
-  }
-
-  ScopedResource response(
-      ppapi,
-      loader_interface->GetResponseInfo(loader.pp_resource()));
-  if (!response.pp_resource()) {
-    errno = EINVAL;
-    return false;
-  }
-
-  // Get response statuscode.
-  PP_Var statuscode = response_interface->GetProperty(
-      response.pp_resource(),
-      PP_URLRESPONSEPROPERTY_STATUSCODE);
-
-  if (statuscode.type != PP_VARTYPE_INT32) {
-    errno = EINVAL;
-    return false;
-  }
-
-  *out_statuscode = statuscode.value.as_int;
-
-  // Only accept OK or Partial Content.
-  if (*out_statuscode != STATUSCODE_OK &&
-      *out_statuscode != STATUSCODE_PARTIAL_CONTENT) {
-    errno = EINVAL;
-    return false;
-  }
-
-  // Get response headers.
-  PP_Var response_headers_var = response_interface->GetProperty(
-      response.pp_resource(),
-      PP_URLRESPONSEPROPERTY_HEADERS);
-
-  uint32_t response_headers_length;
-  const char* response_headers_str = var_interface->VarToUtf8(
-      response_headers_var,
-      &response_headers_length);
-
-  *out_loader = loader.Release();
-  *out_request = request.Release();
-  *out_response = response.Release();
-  *out_response_headers = ParseHeaders(response_headers_str,
-                                       response_headers_length);
-
-  return true;
-}
-
-int MountNodeHttp::DownloadToCache() {
-  StringMap_t headers;
-  PP_Resource loader;
-  PP_Resource request;
-  PP_Resource response;
-  int32_t statuscode;
-  StringMap_t response_headers;
-  if (!OpenUrl("GET", &headers, &loader, &request, &response, &statuscode,
-               &response_headers)) {
-    // errno is already set by OpenUrl.
-    return -1;
-  }
-
-  PepperInterface* ppapi = mount_->ppapi();
-  ScopedResource scoped_loader(ppapi, loader);
-  ScopedResource scoped_request(ppapi, request);
-  ScopedResource scoped_response(ppapi, response);
-
-  size_t content_length = 0;
-  if (ParseContentLength(response_headers, &content_length)) {
-    cached_data_.resize(content_length);
-    int real_size = DownloadToBuffer(loader, cached_data_.data(),
-                                     content_length);
-    if (real_size < 0)
-      return -1;
-
-    SetCachedSize(real_size);
-    cached_data_.resize(real_size);
-    return real_size;
-  }
-
-  // We don't know how big the file is. Read in chunks.
-  cached_data_.resize(MAX_READ_BUFFER_SIZE);
-  size_t total_bytes_read = 0;
-  size_t bytes_to_read = MAX_READ_BUFFER_SIZE;
-  while (true) {
-    char* buf = cached_data_.data() + total_bytes_read;
-    int bytes_read = DownloadToBuffer(loader, buf, bytes_to_read);
-    if (bytes_read < 0)
-      return -1;
-
-    total_bytes_read += bytes_read;
-
-    if (bytes_read < bytes_to_read) {
-      SetCachedSize(total_bytes_read);
-      cached_data_.resize(total_bytes_read);
-      return total_bytes_read;
-    }
-
-    cached_data_.resize(total_bytes_read + bytes_to_read);
-  }
-}
-
-int MountNodeHttp::ReadPartialFromCache(size_t offs, void* buf, size_t count) {
-  if (offs > cached_data_.size()) {
-    errno = EINVAL;
-    return -1;
-  }
-
-  count = std::min(count, cached_data_.size() - offs);
-  memcpy(buf, &cached_data_.data()[offs], count);
-  return count;
-}
-
-int MountNodeHttp::DownloadPartial(size_t offs, void* buf, size_t count) {
-  StringMap_t headers;
-
-  char buffer[100];
-  // Range request is inclusive: 0-99 returns 100 bytes.
-  snprintf(&buffer[0], sizeof(buffer), "bytes=%"PRIuS"-%"PRIuS,
-           offs, offs + count - 1);
-  headers["Range"] = buffer;
-
-  PP_Resource loader;
-  PP_Resource request;
-  PP_Resource response;
-  int32_t statuscode;
-  StringMap_t response_headers;
-  if (!OpenUrl("GET", &headers, &loader, &request, &response, &statuscode,
-               &response_headers)) {
-    // errno is already set by OpenUrl.
-    return -1;
-  }
-
-  PepperInterface* ppapi = mount_->ppapi();
-  ScopedResource scoped_loader(ppapi, loader);
-  ScopedResource scoped_request(ppapi, request);
-  ScopedResource scoped_response(ppapi, response);
-
-  size_t read_start = 0;
-  if (statuscode == STATUSCODE_OK) {
-    // No partial result, read everything starting from the part we care about.
-    size_t content_length;
-    if (ParseContentLength(response_headers, &content_length)) {
-      if (offs >= content_length) {
-        errno = EINVAL;
-        return 0;
-      }
+Error MountHttp::Open(const Path& path, int mode, MountNode** out_node) {
+  *out_node = NULL;
 
-      // Clamp count, if trying to read past the end of the file.
-      if (offs + count > content_length) {
-        count = content_length - offs;
-      }
-    }
-  } else if (statuscode == STATUSCODE_PARTIAL_CONTENT) {
-    // Determine from the headers where we are reading.
-    size_t read_end;
-    size_t entity_length;
-    if (ParseContentRange(response_headers, &read_start, &read_end,
-                          &entity_length)) {
-      if (read_start > offs || read_start > read_end) {
-        // If this error occurs, the server is returning bogus values.
-        errno = EINVAL;
-        return -1;
-      }
+  assert(url_root_.empty() || url_root_[url_root_.length() - 1] == '/');
 
-      // Clamp count, if trying to read past the end of the file.
-      count = std::min(read_end - read_start, count);
-    } else {
-      // Partial Content without Content-Range. Assume that the server gave us
-      // exactly what we asked for. This can happen even when the server
-      // returns 200 -- the cache may return 206 in this case, but not modify
-      // the headers.
-      read_start = offs;
-    }
+  NodeMap_t::iterator iter = node_cache_.find(path.Join());
+  if (iter != node_cache_.end()) {
+    *out_node = iter->second;
+    return 0;
   }
 
-  if (read_start < offs) {
-    // We aren't yet at the location where we want to start reading. Read into
-    // our dummy buffer until then.
-    size_t bytes_to_read = offs - read_start;
-    if (buffer_.size() < bytes_to_read)
-      buffer_.resize(std::min(bytes_to_read, MAX_READ_BUFFER_SIZE));
-
-    while (bytes_to_read > 0) {
-      int32_t bytes_read = DownloadToBuffer(loader, buffer_.data(),
-                                            buffer_.size());
-      if (bytes_read < 0)
-        return -1;
+  // If we can't find the node in the cache, create it
+  std::string url = url_root_ + (path.IsAbsolute() ? path.Range(1, path.Size())
+                                                   : path.Join());
 
-      bytes_to_read -= bytes_read;
-    }
+  MountNodeHttp* node = new MountNodeHttp(this, url, cache_content_);
+  Error error = node->Init(mode);
+  if (error) {
+    node->Release();
+    return error;
   }
 
-  return DownloadToBuffer(loader, buf, count);
-}
-
-int MountNodeHttp::DownloadToBuffer(PP_Resource loader, void* buf,
-                                    size_t count) {
-  PepperInterface* ppapi = mount_->ppapi();
-  URLLoaderInterface* loader_interface = ppapi->GetURLLoaderInterface();
-
-  char* out_buffer = static_cast<char*>(buf);
-  size_t bytes_to_read = count;
-  while (bytes_to_read > 0) {
-    int32_t bytes_read = loader_interface->ReadResponseBody(
-        loader, out_buffer, bytes_to_read, PP_BlockUntilComplete());
-
-    if (bytes_read == 0) {
-      // This is not an error -- it may just be that we were trying to read
-      // more data than exists.
-      return count - bytes_to_read;
-    }
-
-    if (bytes_read < 0) {
-      errno = PPErrorToErrno(bytes_read);
-      return -1;
-    }
-
-    assert(bytes_read <= bytes_to_read);
-    bytes_to_read -= bytes_read;
-    out_buffer += bytes_read;
+  error = node->GetStat(NULL);
+  if (error) {
+    node->Release();
+    return error;
   }
 
-  return count;
-}
-
-MountNode *MountHttp::Open(const Path& path, int mode) {
-  assert(url_root_.empty() || url_root_[url_root_.length() - 1] == '/');
-
-  NodeMap_t::iterator iter = node_cache_.find(path.Join());
-  if (iter != node_cache_.end()) {
-    return iter->second;
+  MountNodeDir* parent;
+  error = FindOrCreateDir(path.Parent(), &parent);
+  if (error) {
+    node->Release();
+    return error;
   }
 
-  // If we can't find the node in the cache, create it
-  std::string url = url_root_ + (path.IsAbsolute() ?
-      path.Range(1, path.Size()) :
-      path.Join());
-
-  MountNodeHttp* node = new MountNodeHttp(this, url, cache_content_);
-  if (!node->Init(mode) || (0 != node->GetStat(NULL))) {
+  error = parent->AddChild(path.Basename(), node);
+  if (error) {
     node->Release();
-    return NULL;
+    return error;
   }
 
-  MountNodeDir* parent = FindOrCreateDir(path.Parent());
   node_cache_[path.Join()] = node;
-  parent->AddChild(path.Basename(), node);
-  return node;
-}
 
-int MountHttp::Unlink(const Path& path) {
-  errno = ENOSYS;
-  return -1;
+  *out_node = node;
+  return 0;
 }
 
-int MountHttp::Mkdir(const Path& path, int permissions) {
-  errno = ENOSYS;
-  return -1;
-}
+Error MountHttp::Unlink(const Path& path) { return ENOSYS; }
 
-int MountHttp::Rmdir(const Path& path) {
-  errno = ENOSYS;
-  return -1;
-}
+Error MountHttp::Mkdir(const Path& path, int permissions) { return ENOSYS; }
 
-int MountHttp::Remove(const Path& path) {
-  errno = ENOSYS;
-  return -1;
-}
+Error MountHttp::Rmdir(const Path& path) { return ENOSYS; }
+
+Error MountHttp::Remove(const Path& path) { return ENOSYS; }
 
-PP_Resource MountHttp::MakeUrlRequestInfo(
-    const std::string& url,
-    const char* method,
-    StringMap_t* additional_headers) {
+PP_Resource MountHttp::MakeUrlRequestInfo(const std::string& url,
+                                          const char* method,
+                                          StringMap_t* additional_headers) {
   URLRequestInfoInterface* interface = ppapi_->GetURLRequestInfoInterface();
   VarInterface* var_interface = ppapi_->GetVarInterface();
 
@@ -618,21 +119,23 @@ PP_Resource MountHttp::MakeUrlRequestInfo(
   if (!request_info)
     return 0;
 
-  interface->SetProperty(
-      request_info, PP_URLREQUESTPROPERTY_URL,
-      var_interface->VarFromUtf8(url.c_str(), url.length()));
-  interface->SetProperty(request_info, PP_URLREQUESTPROPERTY_METHOD,
+  interface->SetProperty(request_info,
+                         PP_URLREQUESTPROPERTY_URL,
+                         var_interface->VarFromUtf8(url.c_str(), url.length()));
+  interface->SetProperty(request_info,
+                         PP_URLREQUESTPROPERTY_METHOD,
                          var_interface->VarFromUtf8(method, strlen(method)));
   interface->SetProperty(request_info,
                          PP_URLREQUESTPROPERTY_ALLOWCROSSORIGINREQUESTS,
                          PP_MakeBool(allow_cors_ ? PP_TRUE : PP_FALSE));
-  interface->SetProperty(request_info, PP_URLREQUESTPROPERTY_ALLOWCREDENTIALS,
+  interface->SetProperty(request_info,
+                         PP_URLREQUESTPROPERTY_ALLOWCREDENTIALS,
                          PP_MakeBool(allow_credentials_ ? PP_TRUE : PP_FALSE));
 
   // Merge the mount headers with the request headers. If the field is already
   // set it |additional_headers|, don't use the one from headers_.
   for (StringMap_t::iterator iter = headers_.begin(); iter != headers_.end();
-      ++iter) {
+       ++iter) {
     const std::string& key = NormalizeHeaderKey(iter->first);
     if (additional_headers->find(key) == additional_headers->end()) {
       additional_headers->insert(std::make_pair(key, iter->second));
@@ -642,12 +145,14 @@ PP_Resource MountHttp::MakeUrlRequestInfo(
   // Join the headers into one string.
   std::string headers;
   for (StringMap_t::iterator iter = additional_headers->begin();
-      iter != additional_headers->end(); ++iter) {
+       iter != additional_headers->end();
+       ++iter) {
     headers += iter->first + ": " + iter->second + '\n';
   }
 
   interface->SetProperty(
-      request_info, PP_URLREQUESTPROPERTY_HEADERS,
+      request_info,
+      PP_URLREQUESTPROPERTY_HEADERS,
       var_interface->VarFromUtf8(headers.c_str(), headers.length()));
 
   return request_info;
@@ -657,12 +162,12 @@ MountHttp::MountHttp()
     : allow_cors_(false),
       allow_credentials_(false),
       cache_stat_(true),
-      cache_content_(true) {
-}
+      cache_content_(true) {}
 
-bool MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
-  if (!Mount::Init(dev, args, ppapi))
-    return false;
+Error MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
+  Error error = Mount::Init(dev, args, ppapi);
+  if (error)
+    return error;
 
   // Parse mount args.
   for (StringMap_t::iterator iter = args.begin(); iter != args.end(); ++iter) {
@@ -674,11 +179,18 @@ bool MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
         url_root_ += '/';
       }
     } else if (iter->first == "manifest") {
-      char *text = LoadManifest(iter->second);
-      if (text != NULL) {
-        ParseManifest(text);
+      char* text;
+      error = LoadManifest(iter->second, &text);
+      if (error)
+        return error;
+
+      error = ParseManifest(text);
+      if (error) {
         delete[] text;
+        return error;
       }
+
+      delete[] text;
     } else if (iter->first == "allow_cross_origin_requests") {
       allow_cors_ = iter->second == "true";
     } else if (iter->first == "allow_credentials") {
@@ -693,34 +205,53 @@ bool MountHttp::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
     }
   }
 
-  return true;
+  return 0;
 }
 
-void MountHttp::Destroy() {
-}
+void MountHttp::Destroy() {}
+
+Error MountHttp::FindOrCreateDir(const Path& path, MountNodeDir** out_node) {
+  *out_node = NULL;
 
-MountNodeDir* MountHttp::FindOrCreateDir(const Path& path) {
   std::string strpath = path.Join();
   NodeMap_t::iterator iter = node_cache_.find(strpath);
   if (iter != node_cache_.end()) {
-    return static_cast<MountNodeDir*>(iter->second);
+    *out_node = static_cast<MountNodeDir*>(iter->second);
+    return 0;
   }
 
-  // If the node does not exist, create it, and add it to the node cache
+  // If the node does not exist, create it.
   MountNodeDir* node = new MountNodeDir(this);
-  node->Init(S_IREAD);
-  node_cache_[strpath] = node;
+  Error error = node->Init(S_IREAD);
+  if (error) {
+    node->Release();
+    return error;
+  }
 
   // If not the root node, find the parent node and add it to the parent
   if (!path.Top()) {
-    MountNodeDir* parent = FindOrCreateDir(path.Parent());
-    parent->AddChild(path.Basename(), node);
+    MountNodeDir* parent;
+    error = FindOrCreateDir(path.Parent(), &parent);
+    if (error) {
+      node->Release();
+      return error;
+    }
+
+    error = parent->AddChild(path.Basename(), node);
+    if (error) {
+      node->Release();
+      return error;
+    }
   }
 
-  return node;
+  // Add it to the node cache.
+  node_cache_[strpath] = node;
+
+  *out_node = node;
+  return 0;
 }
 
-bool MountHttp::ParseManifest(char *text) {
+Error MountHttp::ParseManifest(char* text) {
   StringList_t lines;
   SplitString(text, "\n", &lines);
 
@@ -741,62 +272,102 @@ bool MountHttp::ParseManifest(char *text) {
       // Ignore EXEC bit
       int mode = S_IFREG;
       switch (modestr[0]) {
-        case '-': mode = S_IFREG; break;
-        case 'c': mode = S_IFCHR; break;
+        case '-':
+          mode = S_IFREG;
+          break;
+        case 'c':
+          mode = S_IFCHR;
+          break;
         default:
           fprintf(stderr, "Unable to parse type %s for %s.\n", modestr, name);
-          return false;
+          return EINVAL;
       }
 
       switch (modestr[1]) {
-        case '-': break;
-        case 'r': mode |= S_IREAD; break;
+        case '-':
+          break;
+        case 'r':
+          mode |= S_IREAD;
+          break;
         default:
           fprintf(stderr, "Unable to parse read %s for %s.\n", modestr, name);
-          return false;
+          return EINVAL;
       }
 
       switch (modestr[2]) {
-        case '-': break;
-        case 'w': mode |= S_IWRITE; break;
+        case '-':
+          break;
+        case 'w':
+          mode |= S_IWRITE;
+          break;
         default:
           fprintf(stderr, "Unable to parse write %s for %s.\n", modestr, name);
-          return false;
+          return EINVAL;
       }
 
       Path path(name);
-      std::string url = url_root_ + (path.IsAbsolute() ?
-          path.Range(1, path.Size()) :
-          path.Join());
+      std::string url =
+          url_root_ +
+          (path.IsAbsolute() ? path.Range(1, path.Size()) : path.Join());
 
       MountNodeHttp* node = new MountNodeHttp(this, url, cache_content_);
-      node->Init(mode);
+      Error error = node->Init(mode);
+      if (error) {
+        node->Release();
+        return error;
+      }
+
       node->SetCachedSize(atoi(lenstr));
 
-      MountNodeDir* dir_node = FindOrCreateDir(path.Parent());
-      dir_node->AddChild(path.Basename(), node);
+      MountNodeDir* dir_node;
+      error = FindOrCreateDir(path.Parent(), &dir_node);
+      if (error) {
+        node->Release();
+        return error;
+      }
+
+      error = dir_node->AddChild(path.Basename(), node);
+      if (error) {
+        node->Release();
+        return error;
+      }
 
       std::string pname = path.Join();
       node_cache_[pname] = node;
     }
   }
 
-  return true;
+  return 0;
 }
 
-char *MountHttp::LoadManifest(const std::string& manifest_name) {
+Error MountHttp::LoadManifest(const std::string& manifest_name,
+                              char** out_manifest) {
   Path manifest_path(manifest_name);
-  MountNode* manifest_node = Open(manifest_path, O_RDONLY);
+  MountNode* manifest_node = NULL;
+  *out_manifest = NULL;
 
-  if (manifest_node) {
-    char *text = new char[manifest_node->GetSize() + 1];
-    off_t len = manifest_node->Read(0, text, manifest_node->GetSize());
+  int error = Open(manifest_path, O_RDONLY, &manifest_node);
+  if (error)
+    return error;
+
+  size_t size;
+  error = manifest_node->GetSize(&size);
+  if (error) {
     manifest_node->Release();
+    return error;
+  }
 
-    text[len] = 0;
-    return text;
+  char* text = new char[size + 1];
+  int len;
+  error = manifest_node->Read(0, text, size, &len);
+  if (error) {
+    manifest_node->Release();
+    return error;
   }
 
-  fprintf(stderr, "Could not open manifest: %s\n", manifest_name.c_str());
-  return NULL;
+  manifest_node->Release();
+  text[len] = 0;
+
+  *out_manifest = text;
+  return 0;
 }
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_http.h b/native_client_sdk/src/libraries/nacl_io/mount_http.h
index 3a842a041e..e10f1afcfe 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_http.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_http.h
@@ -15,15 +15,17 @@ class MountNodeDir;
 class MountNodeHttp;
 class MountHttpMock;
 
+std::string NormalizeHeaderKey(const std::string& s);
+
 class MountHttp : public Mount {
  public:
   typedef std::map<std::string, MountNode*> NodeMap_t;
 
-  virtual MountNode *Open(const Path& path, int mode);
-  virtual int Unlink(const Path& path);
-  virtual int Mkdir(const Path& path, int permissions);
-  virtual int Rmdir(const Path& path);
-  virtual int Remove(const Path& path);
+  virtual Error Open(const Path& path, int mode, MountNode** out_node);
+  virtual Error Unlink(const Path& path);
+  virtual Error Mkdir(const Path& path, int permissions);
+  virtual Error Rmdir(const Path& path);
+  virtual Error Remove(const Path& path);
 
   PP_Resource MakeUrlRequestInfo(const std::string& url,
                                  const char* method,
@@ -32,11 +34,11 @@ class MountHttp : public Mount {
  protected:
   MountHttp();
 
-  virtual bool Init(int dev, StringMap_t& args, PepperInterface* ppapi);
+  virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi);
   virtual void Destroy();
-  MountNodeDir* FindOrCreateDir(const Path& path);
-  char *LoadManifest(const std::string& path);
-  bool ParseManifest(char *text);
+  Error FindOrCreateDir(const Path& path, MountNodeDir** out_node);
+  Error LoadManifest(const std::string& path, char** out_manifest);
+  Error ParseManifest(char *text);
 
  private:
   std::string url_root_;
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_mem.cc b/native_client_sdk/src/libraries/nacl_io/mount_mem.cc
index fa3035cbcc..356600b4ec 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_mem.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_mem.cc
@@ -14,22 +14,24 @@
 #include "nacl_io/mount_node_mem.h"
 #include "nacl_io/osstat.h"
 #include "nacl_io/path.h"
-#include "utils/auto_lock.h"
-#include "utils/ref_object.h"
+#include "sdk_util/auto_lock.h"
+#include "sdk_util/ref_object.h"
 
-// TODO(noelallen) : Grab/Redefine these in the kernel object once available.
-#define USR_ID 1002
-#define GRP_ID 1003
+MountMem::MountMem() : root_(NULL), max_ino_(0) {}
 
-MountMem::MountMem()
-    : root_(NULL),
-      max_ino_(0) {
-}
+Error MountMem::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
+  Error error = Mount::Init(dev, args, ppapi);
+  if (error)
+    return error;
+
+  root_ = new MountNodeDir(this);
+  error = root_->Init(S_IREAD | S_IWRITE);
+  if (error) {
+    root_->Release();
+    return error;
+  }
 
-bool MountMem::Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
-  Mount::Init(dev, args, ppapi);
-  root_ = AllocatePath(S_IREAD | S_IWRITE);
-  return (bool) (root_ != NULL);
+  return 0;
 }
 
 void MountMem::Destroy() {
@@ -38,173 +40,156 @@ void MountMem::Destroy() {
   root_ = NULL;
 }
 
-MountNode* MountMem::AllocatePath(int mode) {
-  MountNode *ptr = new MountNodeDir(this);
-  if (!ptr->Init(mode)) {
-    ptr->Release();
-    return NULL;
-  }
-  return ptr;
-}
-
-MountNode* MountMem::AllocateData(int mode) {
-  MountNode* ptr = new MountNodeMem(this);
-  if (!ptr->Init(mode)) {
-    ptr->Release();
-    return NULL;
-  }
-  return ptr;
-}
-
-MountNode* MountMem::FindNode(const Path& path, int type) {
+Error MountMem::FindNode(const Path& path, int type, MountNode** out_node) {
   MountNode* node = root_;
 
   // If there is no root there, we have an error.
-  if (node == NULL) {
-    errno = ENOTDIR;
-    return NULL;
-  }
+  if (node == NULL)
+    return ENOTDIR;
 
   // We are expecting an "absolute" path from this mount point.
-  if (!path.IsAbsolute()) {
-    errno = EINVAL;
-    return NULL;
-  }
+  if (!path.IsAbsolute())
+    return EINVAL;
 
   // Starting at the root, traverse the path parts.
   for (size_t index = 1; node && index < path.Size(); index++) {
     // If not a directory, then we have an error so return.
-    if (!node->IsaDir()) {
-      errno = ENOTDIR;
-      return NULL;
-    }
+    if (!node->IsaDir())
+      return ENOTDIR;
 
     // Find the child node
-    node = node->FindChild(path.Part(index));
+    Error error = node->FindChild(path.Part(index), &node);
+    if (error)
+      return error;
   }
 
-  // node should be root, a found child, or a failed 'FindChild'
-  // which already has the correct errno set.
-  if (NULL == node) return NULL;
-
   // If a directory is expected, but it's not a directory, then fail.
-  if ((type & S_IFDIR) && !node->IsaDir()) {
-    errno = ENOTDIR;
-    return NULL;
-  }
+  if ((type & S_IFDIR) && !node->IsaDir())
+    return ENOTDIR;
 
   // If a file is expected, but it's not a file, then fail.
-  if ((type & S_IFREG) && node->IsaDir()) {
-    errno = EISDIR;
-    return NULL;
-  }
+  if ((type & S_IFREG) && node->IsaDir())
+    return EISDIR;
 
   // We now have a valid object of the expected type, so return it.
-  return node;
+  *out_node = node;
+  return 0;
 }
 
-MountNode* MountMem::Open(const Path& path, int mode) {
+Error MountMem::Open(const Path& path, int mode, MountNode** out_node) {
   AutoLock lock(&lock_);
-  MountNode* node = FindNode(path);
+  MountNode* node = NULL;
+  *out_node = NULL;
 
-  if (NULL == node) {
-    // Now first find the parent directory to see if we can add it
-    MountNode* parent = FindNode(path.Parent(), S_IFDIR);
-    if (NULL == parent) return NULL;
+  Error error = FindNode(path, 0, &node);
 
+  if (error) {
     // If the node does not exist and we can't create it, fail
-    if ((mode & O_CREAT) == 0) return NULL;
+    if ((mode & O_CREAT) == 0)
+      return ENOENT;
 
-    // Otherwise, create it with a single reference
-    mode = OpenModeToPermission(mode);
-    node = AllocateData(mode);
-    if (NULL == node) return NULL;
+    // Now first find the parent directory to see if we can add it
+    MountNode* parent = NULL;
+    error = FindNode(path.Parent(), S_IFDIR, &parent);
+    if (error)
+      return error;
+
+    // Create it with a single reference
+    node = new MountNodeMem(this);
+    error = node->Init(OpenModeToPermission(mode));
+    if (error) {
+      node->Release();
+      return error;
+    }
 
-    if (parent->AddChild(path.Basename(), node) == -1) {
+    error = parent->AddChild(path.Basename(), node);
+    if (error) {
       // Or if it fails, release it
       node->Release();
-      return NULL;
+      return error;
     }
-    return node;
+
+    *out_node = node;
+    return 0;
   }
 
+  // Directories can only be opened read-only.
+  if (node->IsaDir() && (mode & 3) != O_RDONLY)
+    return EISDIR;
+
   // If we were expected to create it exclusively, fail
-  if (mode & O_EXCL) {
-    errno = EEXIST;
-    return NULL;
-  }
+  if (mode & O_EXCL)
+    return EEXIST;
 
   // Verify we got the requested permissions.
   int req_mode = OpenModeToPermission(mode);
   int obj_mode = node->GetMode() & OpenModeToPermission(O_RDWR);
-  if ((obj_mode & req_mode) != req_mode) {
-    errno = EACCES;
-    return NULL;
-  }
+  if ((obj_mode & req_mode) != req_mode)
+    return EACCES;
 
   // We opened it, so ref count it before passing it back.
   node->Acquire();
-  return node;
+  *out_node = node;
+  return 0;
 }
 
-int MountMem::Mkdir(const Path& path, int mode) {
+Error MountMem::Mkdir(const Path& path, int mode) {
   AutoLock lock(&lock_);
 
   // We expect a Mount "absolute" path
-  if (!path.IsAbsolute()) {
-    errno = ENOENT;
-    return -1;
-  }
+  if (!path.IsAbsolute())
+    return ENOENT;
 
   // The root of the mount is already created by the mount
-  if (path.Size() == 1) {
-    errno = EEXIST;
-    return -1;
-  }
-
-  MountNode* parent = FindNode(path.Parent(), S_IFDIR);
-  MountNode* node;
+  if (path.Size() == 1)
+    return EEXIST;
 
-  // If we failed to find the parent, the error code is already set.
-  if (NULL == parent) return -1;
+  MountNode* parent = NULL;
+  int error = FindNode(path.Parent(), S_IFDIR, &parent);
+  if (error)
+    return error;
 
-  node = parent->FindChild(path.Basename());
-  if (NULL != node) {
-    errno = EEXIST;
-    return -1;
-  }
+  MountNode* node = NULL;
+  error = parent->FindChild(path.Basename(), &node);
+  if (!error)
+    return EEXIST;
 
-  // Otherwise, create a new node and attempt to add it
-  mode = OpenModeToPermission(mode);
+  if (error != ENOENT)
+    return error;
 
   // Allocate a node, with a RefCount of 1.  If added to the parent
   // it will get ref counted again.  In either case, release the
   // recount we have on exit.
-  node = AllocatePath(S_IREAD | S_IWRITE);
-  if (NULL == node) return -1;
+  node = new MountNodeDir(this);
+  error = node->Init(S_IREAD | S_IWRITE);
+  if (error) {
+    node->Release();
+    return error;
+  }
 
-  if (parent->AddChild(path.Basename(), node) == -1) {
+  error = parent->AddChild(path.Basename(), node);
+  if (error) {
     node->Release();
-    return -1;
+    return error;
   }
 
   node->Release();
   return 0;
 }
 
-int MountMem::Unlink(const Path& path) {
+Error MountMem::Unlink(const Path& path) {
   return RemoveInternal(path, REMOVE_FILE);
 }
 
-int MountMem::Rmdir(const Path& path) {
+Error MountMem::Rmdir(const Path& path) {
   return RemoveInternal(path, REMOVE_DIR);
 }
 
-int MountMem::Remove(const Path& path) {
+Error MountMem::Remove(const Path& path) {
   return RemoveInternal(path, REMOVE_ALL);
 }
 
-int MountMem::RemoveInternal(const Path& path, int remove_type) {
+Error MountMem::RemoveInternal(const Path& path, int remove_type) {
   AutoLock lock(&lock_);
   bool dir_only = remove_type == REMOVE_DIR;
   bool file_only = remove_type == REMOVE_FILE;
@@ -212,40 +197,33 @@ int MountMem::RemoveInternal(const Path& path, int remove_type) {
 
   if (dir_only) {
     // We expect a Mount "absolute" path
-    if (!path.IsAbsolute()) {
-      errno = ENOENT;
-      return -1;
-    }
+    if (!path.IsAbsolute())
+      return ENOENT;
 
     // The root of the mount is already created by the mount
-    if (path.Size() == 1) {
-      errno = EEXIST;
-      return -1;
-    }
+    if (path.Size() == 1)
+      return EEXIST;
   }
 
-  MountNode* parent = FindNode(path.Parent(), S_IFDIR);
-
-  // If we failed to find the parent, the error code is already set.
-  if (NULL == parent) return -1;
+  MountNode* parent = NULL;
+  int error = FindNode(path.Parent(), S_IFDIR, &parent);
+  if (error)
+    return error;
 
   // Verify we find a child which is a directory.
-  MountNode* child = parent->FindChild(path.Basename());
-  if (NULL == child) {
-    errno = ENOENT;
-    return -1;
-  }
-  if (dir_only && !child->IsaDir()) {
-    errno = ENOTDIR;
-    return -1;
-  }
-  if (file_only && child->IsaDir()) {
-    errno = EISDIR;
-    return -1;
-  }
-  if (remove_dir && child->ChildCount() > 0) {
-    errno = ENOTEMPTY;
-    return -1;
-  }
+  MountNode* child = NULL;
+  error = parent->FindChild(path.Basename(), &child);
+  if (error)
+    return error;
+
+  if (dir_only && !child->IsaDir())
+    return ENOTDIR;
+
+  if (file_only && child->IsaDir())
+    return EISDIR;
+
+  if (remove_dir && child->ChildCount() > 0)
+    return ENOTEMPTY;
+
   return parent->RemoveChild(path.Basename());
 }
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_mem.h b/native_client_sdk/src/libraries/nacl_io/mount_mem.h
index dc75e81769..930e9c734a 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_mem.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_mem.h
@@ -14,35 +14,33 @@ class MountMem : public Mount {
  protected:
   MountMem();
 
-  virtual bool Init(int dev, StringMap_t& args, PepperInterface* ppapi);
+  virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi);
   virtual void Destroy();
 
   // The protected functions are only used internally and will not
   // acquire or release the mount's lock themselves.  The caller is
   // required to use correct locking as needed.
-  MountNode *AllocateData(int mode);
-  MountNode *AllocatePath(int mode);
 
   // Allocate or free an INODE number.
   int AllocateINO();
   void FreeINO(int ino);
 
   // Find a Node specified node optionally failing if type does not match.
-  virtual MountNode* FindNode(const Path& path, int type = 0);
+  virtual Error FindNode(const Path& path, int type, MountNode** out_node);
 
  public:
-  virtual MountNode *Open(const Path& path, int mode);
-  virtual int Unlink(const Path& path);
-  virtual int Mkdir(const Path& path, int perm);
-  virtual int Rmdir(const Path& path);
-  virtual int Remove(const Path& path);
+  virtual Error Open(const Path& path, int mode, MountNode** out_node);
+  virtual Error Unlink(const Path& path);
+  virtual Error Mkdir(const Path& path, int perm);
+  virtual Error Rmdir(const Path& path);
+  virtual Error Remove(const Path& path);
 
 private:
   static const int REMOVE_DIR = 1;
   static const int REMOVE_FILE = 2;
   static const int REMOVE_ALL = REMOVE_DIR | REMOVE_FILE;
 
-  int RemoveInternal(const Path& path, int remove_type);
+  Error RemoveInternal(const Path& path, int remove_type);
 
   MountNode* root_;
   size_t max_ino_;
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node.cc b/native_client_sdk/src/libraries/nacl_io/mount_node.cc
index ff722b44eb..34de7a8164 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node.cc
@@ -13,13 +13,12 @@
 #include "nacl_io/kernel_wrap_real.h"
 #include "nacl_io/mount.h"
 #include "nacl_io/osmman.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
 
 static const int USR_ID = 1001;
 static const int GRP_ID = 1002;
 
-MountNode::MountNode(Mount* mount)
-    : mount_(mount) {
+MountNode::MountNode(Mount* mount) : mount_(mount) {
   memset(&stat_, 0, sizeof(stat_));
   stat_.st_gid = GRP_ID;
   stat_.st_uid = USR_ID;
@@ -32,12 +31,11 @@ MountNode::MountNode(Mount* mount)
     stat_.st_ino = 1;
 }
 
-MountNode::~MountNode() {
-}
+MountNode::~MountNode() {}
 
-bool MountNode::Init(int perm) {
+Error MountNode::Init(int perm) {
   stat_.st_mode |= perm;
-  return true;
+  return 0;
 }
 
 void MountNode::Destroy() {
@@ -46,119 +44,110 @@ void MountNode::Destroy() {
   }
 }
 
-int MountNode::FSync() {
-  return 0;
-}
+Error MountNode::FSync() { return 0; }
 
-int MountNode::FTruncate(off_t length) {
-  errno = EINVAL;
-  return -1;
+Error MountNode::FTruncate(off_t length) {
+  return EINVAL;
 }
 
-int MountNode::GetDents(size_t offs, struct dirent* pdir, size_t count) {
-  errno = ENOTDIR;
-  return -1;
+Error MountNode::GetDents(size_t offs,
+                          struct dirent* pdir,
+                          size_t count,
+                          int* out_bytes) {
+  *out_bytes = 0;
+  return ENOTDIR;
 }
 
-int MountNode::GetStat(struct stat* pstat) {
+Error MountNode::GetStat(struct stat* pstat) {
   AutoLock lock(&lock_);
   memcpy(pstat, &stat_, sizeof(stat_));
   return 0;
 }
 
-int MountNode::Ioctl(int request, char* arg) {
-  errno = EINVAL;
-  return -1;
+Error MountNode::Ioctl(int request, char* arg) {
+  return EINVAL;
 }
 
-int MountNode::Read(size_t offs, void* buf, size_t count) {
-  errno = EINVAL;
-  return -1;
+Error MountNode::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
+  *out_bytes = 0;
+  return EINVAL;
 }
 
-int MountNode::Write(size_t offs, const void* buf, size_t count) {
-  errno = EINVAL;
-  return -1;
+Error MountNode::Write(size_t offs,
+                       const void* buf,
+                       size_t count,
+                       int* out_bytes) {
+  *out_bytes = 0;
+  return EINVAL;
 }
 
-void* MountNode::MMap(void* addr, size_t length, int prot, int flags,
-                      size_t offset) {
+Error MountNode::MMap(void* addr,
+                      size_t length,
+                      int prot,
+                      int flags,
+                      size_t offset,
+                      void** out_addr) {
+  *out_addr = NULL;
+
   // Never allow mmap'ing PROT_EXEC. The passthrough node supports this, but we
   // don't. Fortunately, glibc will fallback if this fails, so dlopen will
   // continue to work.
-  if (prot & PROT_EXEC) {
-    errno = EPERM;
-    return MAP_FAILED;
-  }
+  if (prot & PROT_EXEC)
+    return EPERM;
 
   // This default mmap support is just enough to make dlopen work.
   // This implementation just reads from the mount into the mmap'd memory area.
   void* new_addr = addr;
-  int err = _real_mmap(&new_addr, length, prot | PROT_WRITE, flags |
-                       MAP_ANONYMOUS, -1, 0);
+  int mmap_error = _real_mmap(
+      &new_addr, length, prot | PROT_WRITE, flags | MAP_ANONYMOUS, -1, 0);
   if (new_addr == MAP_FAILED) {
     _real_munmap(new_addr, length);
-    errno = err;
-    return MAP_FAILED;
+    return mmap_error;
   }
 
-  ssize_t cnt = Read(offset, new_addr, length);
-  if (cnt == -1) {
+  int bytes_read;
+  Error read_error = Read(offset, new_addr, length, &bytes_read);
+  if (read_error) {
     _real_munmap(new_addr, length);
-    errno = ENOSYS;
-    return MAP_FAILED;
+    return read_error;
   }
 
-  return new_addr;
-}
-
-int MountNode::GetLinks() {
-  return stat_.st_nlink;
+  *out_addr = new_addr;
+  return 0;
 }
 
-int MountNode::GetMode() {
-  return stat_.st_mode & ~S_IFMT;
-}
+int MountNode::GetLinks() { return stat_.st_nlink; }
 
-size_t MountNode::GetSize() {
-  return stat_.st_size;
-}
+int MountNode::GetMode() { return stat_.st_mode & ~S_IFMT; }
 
-int MountNode::GetType() {
-  return stat_.st_mode & S_IFMT;
+Error MountNode::GetSize(size_t* out_size) {
+  *out_size = stat_.st_size;
+  return 0;
 }
 
-bool MountNode::IsaDir() {
-  return (stat_.st_mode & S_IFDIR) != 0;
-}
+int MountNode::GetType() { return stat_.st_mode & S_IFMT; }
 
-bool MountNode::IsaFile() {
-  return (stat_.st_mode & S_IFREG) != 0;
-}
+bool MountNode::IsaDir() { return (stat_.st_mode & S_IFDIR) != 0; }
 
-bool MountNode::IsaTTY() {
-  return (stat_.st_mode & S_IFCHR) != 0;
-}
+bool MountNode::IsaFile() { return (stat_.st_mode & S_IFREG) != 0; }
 
+bool MountNode::IsaTTY() { return (stat_.st_mode & S_IFCHR) != 0; }
 
-int MountNode:: AddChild(const std::string& name, MountNode* node) {
-  errno = ENOTDIR;
-  return -1;
+Error MountNode::AddChild(const std::string& name, MountNode* node) {
+  return ENOTDIR;
 }
 
-int MountNode::RemoveChild(const std::string& name) {
-  errno = ENOTDIR;
-  return -1;
+Error MountNode::RemoveChild(const std::string& name) {
+  return ENOTDIR;
 }
 
-MountNode* MountNode::FindChild(const std::string& name) {
-  errno = ENOTDIR;
-  return NULL;
+Error MountNode::FindChild(const std::string& name, MountNode** out_node) {
+  *out_node = NULL;
+  return ENOTDIR;
 }
 
 int MountNode::ChildCount() {
-  errno = ENOTDIR;
-  return -1;
+  return 0;
 }
 
 void MountNode::Link() {
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node.h b/native_client_sdk/src/libraries/nacl_io/mount_node.h
index 36a937e5fb..0acce66f80 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node.h
@@ -7,13 +7,16 @@
 
 #include <string>
 
+#include "nacl_io/error.h"
 #include "nacl_io/osstat.h"
-#include "utils/ref_object.h"
+#include "sdk_util/ref_object.h"
 
 struct dirent;
 struct stat;
 class Mount;
 
+// NOTE: The KernelProxy is the only class that should be setting errno. All
+// other classes should return Error (as defined by nacl_io/error.h).
 class MountNode : public RefObject {
  protected:
   explicit MountNode(Mount* mount);
@@ -21,27 +24,46 @@ class MountNode : public RefObject {
 
  protected:
   // Initialize with node specific flags, in this case stat permissions.
-  virtual bool Init(int flags);
+  virtual Error Init(int flags);
   virtual void Destroy();
 
  public:
   // Normal OS operations on a node (file), can be called by the kernel
   // directly so it must lock and unlock appropriately.  These functions
   // must not be called by the mount.
-  virtual int FSync();
-  virtual int FTruncate(off_t length);
-  virtual int GetDents(size_t offs, struct dirent* pdir, size_t count);
-  virtual int GetStat(struct stat* stat);
-  virtual int Ioctl(int request, char* arg);
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int Write(size_t offs, const void* buf, size_t count);
-  virtual void* MMap(void* addr, size_t length, int prot, int flags,
-                     size_t offset);
+  virtual Error FSync();
+  // It is expected that the derived MountNode will fill with 0 when growing
+  // the file.
+  virtual Error FTruncate(off_t length);
+  // Assume that |out_bytes| is non-NULL.
+  virtual Error GetDents(size_t offs,
+                         struct dirent* pdir,
+                         size_t count,
+                         int* out_bytes);
+  // Assume that |stat| is non-NULL.
+  virtual Error GetStat(struct stat* stat);
+  // Assume that |arg| is non-NULL.
+  virtual Error Ioctl(int request, char* arg);
+  // Assume that |buf| and |out_bytes| are non-NULL.
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  // Assume that |buf| and |out_bytes| are non-NULL.
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
+  // Assume that |addr| and |out_addr| are non-NULL.
+  virtual Error MMap(void* addr,
+                     size_t length,
+                     int prot,
+                     int flags,
+                     size_t offset,
+                     void** out_addr);
 
   virtual int GetLinks();
   virtual int GetMode();
   virtual int GetType();
-  virtual size_t GetSize();
+  // Assume that |out_size| is non-NULL.
+  virtual Error GetSize(size_t *out_size);
   virtual bool IsaDir();
   virtual bool IsaFile();
   virtual bool IsaTTY();
@@ -51,18 +73,20 @@ class MountNode : public RefObject {
   // must be held while these calls are made.
 
   // Adds or removes a directory entry updating the link numbers and refcount
-  virtual int AddChild(const std::string& name, MountNode *node);
-  virtual int RemoveChild(const std::string& name);
+  // Assumes that |node| is non-NULL.
+  virtual Error AddChild(const std::string& name, MountNode* node);
+  virtual Error RemoveChild(const std::string& name);
 
   // Find a child and return it without updating the refcount
-  virtual MountNode* FindChild(const std::string& name);
+  // Assumes that |out_node| is non-NULL.
+  virtual Error FindChild(const std::string& name, MountNode** out_node);
   virtual int ChildCount();
 
   // Update the link count
   virtual void Link();
   virtual void Unlink();
 
-protected:
+ protected:
   struct stat stat_;
   Mount* mount_;
 
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_dir.cc b/native_client_sdk/src/libraries/nacl_io/mount_node_dir.cc
index 7a33bfd684..6f7feab44a 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_dir.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_dir.cc
@@ -9,78 +9,82 @@
 
 #include "nacl_io/osdirent.h"
 #include "nacl_io/osstat.h"
-#include "utils/macros.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
+#include "sdk_util/macros.h"
 
-MountNodeDir::MountNodeDir(Mount* mount)
-    : MountNode(mount),
-      cache_(NULL) {
+MountNodeDir::MountNodeDir(Mount* mount) : MountNode(mount), cache_(NULL) {
   stat_.st_mode |= S_IFDIR;
 }
 
 MountNodeDir::~MountNodeDir() {
+  for (MountNodeMap_t::iterator it = map_.begin(); it != map_.end(); ++it) {
+    it->second->Unlink();
+  }
   free(cache_);
 }
 
-int MountNodeDir::Read(size_t offs, void *buf, size_t count) {
-  errno = EISDIR;
-  return -1;
+Error MountNodeDir::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
+  *out_bytes = 0;
+  return EISDIR;
 }
 
-int MountNodeDir::FTruncate(off_t size) {
-  errno = EISDIR;
-  return -1;
-}
+Error MountNodeDir::FTruncate(off_t size) { return EISDIR; }
 
-int MountNodeDir::Write(size_t offs, void *buf, size_t count) {
-  errno = EISDIR;
-  return -1;
+Error MountNodeDir::Write(size_t offs,
+                          void* buf,
+                          size_t count,
+                          int* out_bytes) {
+  *out_bytes = 0;
+  return EISDIR;
 }
 
-int MountNodeDir::GetDents(size_t offs, struct dirent* pdir, size_t size) {
+Error MountNodeDir::GetDents(size_t offs,
+                             struct dirent* pdir,
+                             size_t size,
+                             int* out_bytes) {
+  *out_bytes = 0;
+
   AutoLock lock(&lock_);
 
   // If the buffer pointer is invalid, fail
-  if (NULL == pdir) {
-    errno = EINVAL;
-    return -1;
-  }
+  if (NULL == pdir)
+    return EINVAL;
 
   // If the buffer is too small, fail
-  if (size < sizeof(struct dirent)) {
-    errno = EINVAL;
-    return -1;
-  }
+  if (size < sizeof(struct dirent))
+    return EINVAL;
 
   // Force size to a multiple of dirent
   size -= size % sizeof(struct dirent);
   size_t max = map_.size() * sizeof(struct dirent);
-  if (cache_ == NULL) BuildCache();
+  if (cache_ == NULL)
+    BuildCache();
 
-  if (offs >= max) return 0;
-  if (offs + size >= max) size = max - offs;
+  if (offs >= max) {
+    // OK, trying to read past the end.
+    return 0;
+  }
 
-  memcpy(pdir, ((char *) cache_) + offs, size);
-  return size;
+  if (offs + size >= max)
+    size = max - offs;
+
+  memcpy(pdir, ((char*)cache_) + offs, size);
+  *out_bytes = size;
+  return 0;
 }
 
-int MountNodeDir::AddChild(const std::string& name, MountNode* node) {
+Error MountNodeDir::AddChild(const std::string& name, MountNode* node) {
   AutoLock lock(&lock_);
 
-  if (name.empty()) {
-    errno = ENOENT;
-    return -1;
-  }
-  if (name.length() >= MEMBER_SIZE(struct dirent, d_name)) {
-    errno = ENAMETOOLONG;
-    return -1;
-  }
+  if (name.empty())
+    return ENOENT;
+
+  if (name.length() >= MEMBER_SIZE(struct dirent, d_name))
+    return ENAMETOOLONG;
 
   MountNodeMap_t::iterator it = map_.find(name);
-  if (it != map_.end()) {
-    errno = EEXIST;
-    return -1;
-  }
+  if (it != map_.end())
+    return EEXIST;
 
   node->Link();
   map_[name] = node;
@@ -88,7 +92,7 @@ int MountNodeDir::AddChild(const std::string& name, MountNode* node) {
   return 0;
 }
 
-int MountNodeDir::RemoveChild(const std::string& name) {
+Error MountNodeDir::RemoveChild(const std::string& name) {
   AutoLock lock(&lock_);
   MountNodeMap_t::iterator it = map_.find(name);
   if (it != map_.end()) {
@@ -97,18 +101,19 @@ int MountNodeDir::RemoveChild(const std::string& name) {
     ClearCache();
     return 0;
   }
-  errno = ENOENT;
-  return -1;
+  return ENOENT;
 }
 
-MountNode* MountNodeDir::FindChild(const std::string& name) {
+Error MountNodeDir::FindChild(const std::string& name, MountNode** out_node) {
+  *out_node = NULL;
+
   AutoLock lock(&lock_);
   MountNodeMap_t::iterator it = map_.find(name);
-  if (it != map_.end()) {
-    return it->second;
-  }
-  errno = ENOENT;
-  return NULL;
+  if (it == map_.end())
+    return ENOENT;
+
+  *out_node = it->second;
+  return 0;
 }
 
 int MountNodeDir::ChildCount() {
@@ -123,7 +128,7 @@ void MountNodeDir::ClearCache() {
 
 void MountNodeDir::BuildCache() {
   if (map_.size()) {
-    cache_ = (struct dirent *) malloc(sizeof(struct dirent) * map_.size());
+    cache_ = (struct dirent*)malloc(sizeof(struct dirent) * map_.size());
     MountNodeMap_t::iterator it = map_.begin();
     for (size_t index = 0; it != map_.end(); it++, index++) {
       MountNode* node = it->second;
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_dir.h b/native_client_sdk/src/libraries/nacl_io/mount_node_dir.h
index b6af58dda2..a2ab67ecfa 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_dir.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_dir.h
@@ -25,15 +25,18 @@ class MountNodeDir : public MountNode {
  public:
   typedef std::map<std::string, MountNode*> MountNodeMap_t;
 
-  virtual int FTruncate(off_t size);
-  virtual int GetDents(size_t offs, struct dirent* pdir, size_t count);
-  virtual int Read(size_t offs, void *buf, size_t count);
-  virtual int Write(size_t offs, void *buf, size_t count);
+  virtual Error FTruncate(off_t size);
+  virtual Error GetDents(size_t offs,
+                         struct dirent* pdir,
+                         size_t count,
+                         int* out_bytes);
+  virtual Error Read(size_t offs, void *buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs, void *buf, size_t count, int* out_bytes);
 
   // Adds a finds or adds a directory entry as an INO, updating the refcount
-  virtual int AddChild(const std::string& name, MountNode *node);
-  virtual int RemoveChild(const std::string& name);
-  virtual MountNode* FindChild(const std::string& name);
+  virtual Error AddChild(const std::string& name, MountNode *node);
+  virtual Error RemoveChild(const std::string& name);
+  virtual Error FindChild(const std::string& name, MountNode** out_node);
   virtual int ChildCount();
 
 
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.cc b/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.cc
index fb0d5ed2fb..8be2a4f74b 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.cc
@@ -17,7 +17,7 @@
 #include "nacl_io/mount.h"
 #include "nacl_io/osdirent.h"
 #include "nacl_io/pepper_interface.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
 
 namespace {
 
@@ -55,56 +55,61 @@ int32_t ModeToOpenFlags(int mode) {
       break;
   }
 
-  if (mode & O_CREAT) open_flags |= PP_FILEOPENFLAG_CREATE;
-  if (mode & O_TRUNC) open_flags |= PP_FILEOPENFLAG_TRUNCATE;
-  if (mode & O_EXCL) open_flags |= PP_FILEOPENFLAG_EXCLUSIVE;
+  if (mode & O_CREAT)
+    open_flags |= PP_FILEOPENFLAG_CREATE;
+  if (mode & O_TRUNC)
+    open_flags |= PP_FILEOPENFLAG_TRUNCATE;
+  if (mode & O_EXCL)
+    open_flags |= PP_FILEOPENFLAG_EXCLUSIVE;
 
   return open_flags;
 }
 
 }  // namespace
 
-int MountNodeHtml5Fs::FSync() {
-  int32_t result = mount_->ppapi()->GetFileIoInterface()->Flush(
-      fileio_resource_, PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+Error MountNodeHtml5Fs::FSync() {
+  // Cannot call Flush on a directory; simply do nothing.
+  if (IsDirectory())
+    return 0;
 
+  int32_t result = mount_->ppapi()->GetFileIoInterface()
+      ->Flush(fileio_resource_, PP_BlockUntilComplete());
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
   return 0;
 }
 
-int MountNodeHtml5Fs::GetDents(size_t offs, struct dirent* pdir, size_t size) {
+Error MountNodeHtml5Fs::GetDents(size_t offs,
+                                 struct dirent* pdir,
+                                 size_t size,
+                                 int* out_bytes) {
+  *out_bytes = 0;
+
   // If the buffer pointer is invalid, fail
-  if (NULL == pdir) {
-    errno = EINVAL;
-    return -1;
-  }
+  if (NULL == pdir)
+    return EINVAL;
 
   // If the buffer is too small, fail
-  if (size < sizeof(struct dirent)) {
-    errno = EINVAL;
-    return -1;
-  }
+  if (size < sizeof(struct dirent))
+    return EINVAL;
 
-  OutputBuffer output_buf = { NULL, 0 };
-  PP_ArrayOutput output = { &GetOutputBuffer, &output_buf };
-  int32_t result =
-      mount_->ppapi()->GetFileRefInterface()->ReadDirectoryEntries(
-          fileref_resource_, output, PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+  // If this is not a directory, fail
+  if (!IsDirectory())
+    return ENOTDIR;
+
+  OutputBuffer output_buf = {NULL, 0};
+  PP_ArrayOutput output = {&GetOutputBuffer, &output_buf};
+  int32_t result = mount_->ppapi()->GetFileRefInterface()->ReadDirectoryEntries(
+      fileref_resource_, output, PP_BlockUntilComplete());
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
 
   std::vector<struct dirent> dirents;
-  PP_DirectoryEntry* entries =
-      static_cast<PP_DirectoryEntry*>(output_buf.data);
+  PP_DirectoryEntry* entries = static_cast<PP_DirectoryEntry*>(output_buf.data);
 
   for (int i = 0; i < output_buf.element_count; ++i) {
-    PP_Var file_name_var = mount_->ppapi()->GetFileRefInterface()->GetName(
-      entries[i].file_ref);
+    PP_Var file_name_var =
+        mount_->ppapi()->GetFileRefInterface()->GetName(entries[i].file_ref);
 
     // Release the file reference.
     mount_->ppapi()->ReleaseResource(entries[i].file_ref);
@@ -113,18 +118,18 @@ int MountNodeHtml5Fs::GetDents(size_t offs, struct dirent* pdir, size_t size) {
       continue;
 
     uint32_t file_name_length;
-    const char* file_name = mount_->ppapi()->GetVarInterface()->VarToUtf8(
-        file_name_var, &file_name_length);
+    const char* file_name = mount_->ppapi()->GetVarInterface()
+        ->VarToUtf8(file_name_var, &file_name_length);
     if (!file_name)
       continue;
 
     file_name_length = std::min(
         static_cast<size_t>(file_name_length),
-        sizeof(static_cast<struct dirent*>(0)->d_name) - 1); // -1 for NULL.
+        sizeof(static_cast<struct dirent*>(0)->d_name) - 1);  // -1 for NULL.
 
     dirents.push_back(dirent());
     struct dirent& direntry = dirents.back();
-    direntry.d_ino = 0;  // TODO(binji): Is this needed?
+    direntry.d_ino = 1;  // Must be > 0.
     direntry.d_off = sizeof(struct dirent);
     direntry.d_reclen = sizeof(struct dirent);
     strncpy(direntry.d_name, file_name, file_name_length);
@@ -138,33 +143,40 @@ int MountNodeHtml5Fs::GetDents(size_t offs, struct dirent* pdir, size_t size) {
   size -= size % sizeof(struct dirent);
   size_t max = dirents.size() * sizeof(struct dirent);
 
-  if (offs >= max) return 0;
-  if (offs + size >= max) size = max - offs;
+  if (offs >= max)
+    return 0;
+
+  if (offs + size >= max)
+    size = max - offs;
 
   memcpy(pdir, reinterpret_cast<char*>(dirents.data()) + offs, size);
+  *out_bytes = size;
   return 0;
 }
 
-int MountNodeHtml5Fs::GetStat(struct stat* stat) {
+Error MountNodeHtml5Fs::GetStat(struct stat* stat) {
   AutoLock lock(&lock_);
 
   PP_FileInfo info;
-  int32_t result = mount_->ppapi()->GetFileIoInterface()->Query(
-      fileio_resource_, &info, PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+  int32_t result = mount_->ppapi()->GetFileRefInterface()->Query(
+      fileref_resource_, &info, PP_BlockUntilComplete());
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
 
   // Fill in known info here.
   memcpy(stat, &stat_, sizeof(stat_));
 
   // Fill in the additional info from ppapi.
   switch (info.type) {
-    case PP_FILETYPE_REGULAR: stat->st_mode |= S_IFREG; break;
-    case PP_FILETYPE_DIRECTORY: stat->st_mode |= S_IFDIR; break;
+    case PP_FILETYPE_REGULAR:
+      stat->st_mode |= S_IFREG;
+      break;
+    case PP_FILETYPE_DIRECTORY:
+      stat->st_mode |= S_IFDIR;
+      break;
     case PP_FILETYPE_OTHER:
-    default: break;
+    default:
+      break;
   }
   stat->st_size = static_cast<off_t>(info.size);
   stat->st_atime = info.last_access_time;
@@ -174,78 +186,107 @@ int MountNodeHtml5Fs::GetStat(struct stat* stat) {
   return 0;
 }
 
-int MountNodeHtml5Fs::Read(size_t offs, void* buf, size_t count) {
-  int32_t result = mount_->ppapi()->GetFileIoInterface()->Read(
-      fileio_resource_, offs, static_cast<char*>(buf),
-      static_cast<int32_t>(count),
-      PP_BlockUntilComplete());
-  if (result < 0) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+Error MountNodeHtml5Fs::Read(size_t offs,
+                             void* buf,
+                             size_t count,
+                             int* out_bytes) {
+  *out_bytes = 0;
+
+  if (IsDirectory())
+    return EISDIR;
 
-  return result;
+  int32_t result =
+      mount_->ppapi()->GetFileIoInterface()->Read(fileio_resource_,
+                                                  offs,
+                                                  static_cast<char*>(buf),
+                                                  static_cast<int32_t>(count),
+                                                  PP_BlockUntilComplete());
+  if (result < 0)
+    return PPErrorToErrno(result);
+
+  *out_bytes = result;
+  return 0;
 }
 
-int MountNodeHtml5Fs::FTruncate(off_t size) {
-  int32_t result = mount_->ppapi()->GetFileIoInterface()->SetLength(
-      fileio_resource_, size, PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+Error MountNodeHtml5Fs::FTruncate(off_t size) {
+  if (IsDirectory())
+    return EISDIR;
 
+  int32_t result = mount_->ppapi()->GetFileIoInterface()
+      ->SetLength(fileio_resource_, size, PP_BlockUntilComplete());
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
   return 0;
 }
 
-int MountNodeHtml5Fs::Write(size_t offs, const void* buf, size_t count) {
-  int32_t result = mount_->ppapi()->GetFileIoInterface()->Write(
-      fileio_resource_, offs, static_cast<const char*>(buf),
-      static_cast<int32_t>(count), PP_BlockUntilComplete());
-  if (result < 0) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
-
-  return result;
+Error MountNodeHtml5Fs::Write(size_t offs,
+                              const void* buf,
+                              size_t count,
+                              int* out_bytes) {
+  *out_bytes = 0;
+
+  if (IsDirectory())
+    return EISDIR;
+
+  int32_t result = mount_->ppapi()->GetFileIoInterface()
+      ->Write(fileio_resource_,
+              offs,
+              static_cast<const char*>(buf),
+              static_cast<int32_t>(count),
+              PP_BlockUntilComplete());
+  if (result < 0)
+    return PPErrorToErrno(result);
+
+  *out_bytes = result;
+  return 0;
 }
 
-size_t MountNodeHtml5Fs::GetSize() {
+Error MountNodeHtml5Fs::GetSize(size_t* out_size) {
+  *out_size = 0;
+
   AutoLock lock(&lock_);
 
   PP_FileInfo info;
-  int32_t result = mount_->ppapi()->GetFileIoInterface()->Query(
-      fileio_resource_, &info, PP_BlockUntilComplete());
-  if (result != PP_OK) {
-    errno = PPErrorToErrno(result);
-    return -1;
-  }
+  int32_t result = mount_->ppapi()->GetFileIoInterface()
+      ->Query(fileio_resource_, &info, PP_BlockUntilComplete());
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
 
-  return static_cast<size_t>(info.size);
+  *out_size = static_cast<size_t>(info.size);
+  return 0;
 }
 
 MountNodeHtml5Fs::MountNodeHtml5Fs(Mount* mount, PP_Resource fileref_resource)
     : MountNode(mount),
       fileref_resource_(fileref_resource),
-      fileio_resource_(0) {
-}
-
-bool MountNodeHtml5Fs::Init(int perm) {
-  if (!MountNode::Init(Mount::OpenModeToPermission(perm)))
-    return false;
-
-  fileio_resource_= mount_->ppapi()->GetFileIoInterface()->Create(
-      mount_->ppapi()->GetInstance());
+      fileio_resource_(0) {}
+
+Error MountNodeHtml5Fs::Init(int perm) {
+  Error error = MountNode::Init(Mount::OpenModeToPermission(perm));
+  if (error)
+    return error;
+
+  // First query the FileRef to see if it is a file or directory.
+  PP_FileInfo file_info;
+  mount_->ppapi()->GetFileRefInterface()->Query(fileref_resource_, &file_info,
+                                                PP_BlockUntilComplete());
+  // If this is a directory, do not get a FileIO.
+  if (file_info.type == PP_FILETYPE_DIRECTORY)
+    return 0;
+
+  fileio_resource_ = mount_->ppapi()->GetFileIoInterface()
+      ->Create(mount_->ppapi()->GetInstance());
   if (!fileio_resource_)
-    return false;
+    return ENOSYS;
 
-  int32_t open_result = mount_->ppapi()->GetFileIoInterface()->Open(
-      fileio_resource_, fileref_resource_, ModeToOpenFlags(perm),
-      PP_BlockUntilComplete());
+  int32_t open_result =
+      mount_->ppapi()->GetFileIoInterface()->Open(fileio_resource_,
+                                                  fileref_resource_,
+                                                  ModeToOpenFlags(perm),
+                                                  PP_BlockUntilComplete());
   if (open_result != PP_OK)
-    return false;
-
-  return true;
+    return PPErrorToErrno(open_result);
+  return 0;
 }
 
 void MountNodeHtml5Fs::Destroy() {
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.h b/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.h
index 58b4d13d7e..832d3d40ce 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_html5fs.h
@@ -15,25 +15,36 @@ class MountNodeHtml5Fs : public MountNode {
   // Normal OS operations on a node (file), can be called by the kernel
   // directly so it must lock and unlock appropriately.  These functions
   // must not be called by the mount.
-  virtual int FSync();
-  virtual int GetDents(size_t offs, struct dirent* pdir, size_t count);
-  virtual int GetStat(struct stat* stat);
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int FTruncate(off_t size);
-  virtual int Write(size_t offs, const void* buf, size_t count);
-
-  virtual size_t GetSize();
+  virtual Error FSync();
+  virtual Error GetDents(size_t offs,
+                         struct dirent* pdir,
+                         size_t count,
+                         int* out_bytes);
+  virtual Error GetStat(struct stat* stat);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error FTruncate(off_t size);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
+
+  virtual Error GetSize(size_t *out_size);
 
  protected:
   MountNodeHtml5Fs(Mount* mount, PP_Resource fileref);
 
   // Init with standard open flags
-  virtual bool Init(int o_mode);
+  virtual Error Init(int o_mode);
   virtual void Destroy();
 
  private:
   PP_Resource fileref_resource_;
-  PP_Resource fileio_resource_;
+  PP_Resource fileio_resource_;  // 0 if the file is a directory.
+
+  // Returns true if this node is a directory.
+  bool IsDirectory() const {
+    return !fileio_resource_;
+  }
 
   friend class MountHtml5Fs;
 };
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_http.cc b/native_client_sdk/src/libraries/nacl_io/mount_node_http.cc
new file mode 100644
index 0000000000..5005ff48d3
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_http.cc
@@ -0,0 +1,523 @@
+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "nacl_io/mount_node_http.h"
+
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <ppapi/c/pp_errors.h>
+
+#include "nacl_io/mount_http.h"
+#include "nacl_io/osinttypes.h"
+
+#if defined(WIN32)
+#define snprintf _snprintf
+#endif
+
+namespace {
+
+// If we're attempting to read a partial request, but the server returns a full
+// request, we need to read all of the data up to the start of our partial
+// request into a dummy buffer. This is the maximum size of that buffer.
+const size_t MAX_READ_BUFFER_SIZE = 64 * 1024;
+const int32_t STATUSCODE_OK = 200;
+const int32_t STATUSCODE_PARTIAL_CONTENT = 206;
+
+StringMap_t ParseHeaders(const char* headers, int32_t headers_length) {
+  enum State {
+    FINDING_KEY,
+    SKIPPING_WHITESPACE,
+    FINDING_VALUE,
+  };
+
+  StringMap_t result;
+  std::string key;
+  std::string value;
+
+  State state = FINDING_KEY;
+  const char* start = headers;
+  for (int i = 0; i < headers_length; ++i) {
+    switch (state) {
+      case FINDING_KEY:
+        if (headers[i] == ':') {
+          // Found key.
+          key.assign(start, &headers[i] - start);
+          key = NormalizeHeaderKey(key);
+          state = SKIPPING_WHITESPACE;
+        }
+        break;
+
+      case SKIPPING_WHITESPACE:
+        if (headers[i] == ' ') {
+          // Found whitespace, keep going...
+          break;
+        }
+
+        // Found a non-whitespace, mark this as the start of the value.
+        start = &headers[i];
+        state = FINDING_VALUE;
+      // Fallthrough to start processing value without incrementing i.
+
+      case FINDING_VALUE:
+        if (headers[i] == '\n') {
+          // Found value.
+          value.assign(start, &headers[i] - start);
+          result[key] = value;
+          start = &headers[i + 1];
+          state = FINDING_KEY;
+        }
+        break;
+    }
+  }
+
+  return result;
+}
+
+bool ParseContentLength(const StringMap_t& headers, size_t* content_length) {
+  StringMap_t::const_iterator iter = headers.find("Content-Length");
+  if (iter == headers.end())
+    return false;
+
+  *content_length = strtoul(iter->second.c_str(), NULL, 10);
+  return true;
+}
+
+bool ParseContentRange(const StringMap_t& headers,
+                       size_t* read_start,
+                       size_t* read_end,
+                       size_t* entity_length) {
+  StringMap_t::const_iterator iter = headers.find("Content-Range");
+  if (iter == headers.end())
+    return false;
+
+  // The key should look like "bytes ##-##/##" or "bytes ##-##/*". The last
+  // value is the entity length, which can potentially be * (i.e. unknown).
+  int read_start_int;
+  int read_end_int;
+  int entity_length_int;
+  int result = sscanf(iter->second.c_str(),
+                      "bytes %" SCNuS "-%" SCNuS "/%" SCNuS,
+                      &read_start_int,
+                      &read_end_int,
+                      &entity_length_int);
+
+  // The Content-Range header specifies an inclusive range: e.g. the first ten
+  // bytes is "bytes 0-9/*". Convert it to a half-open range by incrementing
+  // read_end.
+  if (result == 2) {
+    *read_start = read_start_int;
+    *read_end = read_end_int + 1;
+    *entity_length = 0;
+    return true;
+  } else if (result == 3) {
+    *read_start = read_start_int;
+    *read_end = read_end_int + 1;
+    *entity_length = entity_length_int;
+    return true;
+  }
+
+  return false;
+}
+
+}  // namespace
+
+void MountNodeHttp::SetCachedSize(off_t size) {
+  has_cached_size_ = true;
+  stat_.st_size = size;
+}
+
+Error MountNodeHttp::FSync() { return ENOSYS; }
+
+Error MountNodeHttp::GetDents(size_t offs,
+                              struct dirent* pdir,
+                              size_t count,
+                              int* out_bytes) {
+  *out_bytes = 0;
+  return ENOSYS;
+}
+
+Error MountNodeHttp::GetStat(struct stat* stat) {
+  AutoLock lock(&lock_);
+
+  // Assume we need to 'HEAD' if we do not know the size, otherwise, assume
+  // that the information is constant.  We can add a timeout if needed.
+  MountHttp* mount = static_cast<MountHttp*>(mount_);
+  if (stat_.st_size == 0 || !mount->cache_stat_) {
+    StringMap_t headers;
+    PP_Resource loader;
+    PP_Resource request;
+    PP_Resource response;
+    int32_t statuscode;
+    StringMap_t response_headers;
+    Error error = OpenUrl("HEAD",
+                          &headers,
+                          &loader,
+                          &request,
+                          &response,
+                          &statuscode,
+                          &response_headers);
+    if (error)
+      return error;
+
+    ScopedResource scoped_loader(mount_->ppapi(), loader);
+    ScopedResource scoped_request(mount_->ppapi(), request);
+    ScopedResource scoped_response(mount_->ppapi(), response);
+
+    size_t entity_length;
+    if (ParseContentLength(response_headers, &entity_length)) {
+      SetCachedSize(static_cast<off_t>(entity_length));
+    } else if (cache_content_ && !has_cached_size_) {
+      error = DownloadToCache();
+      // TODO(binji): this error should not be dropped, but it requires a bit
+      // of a refactor of the tests. See crbug.com/245431
+      // if (error)
+      //   return error;
+    } else {
+      // Don't use SetCachedSize here -- it is actually unknown.
+      stat_.st_size = 0;
+    }
+
+    stat_.st_atime = 0;  // TODO(binji): Use "Last-Modified".
+    stat_.st_mtime = 0;
+    stat_.st_ctime = 0;
+  }
+
+  // Fill the stat structure if provided
+  if (stat)
+    memcpy(stat, &stat_, sizeof(stat_));
+
+  return 0;
+}
+
+Error MountNodeHttp::Read(size_t offs,
+                          void* buf,
+                          size_t count,
+                          int* out_bytes) {
+  *out_bytes = 0;
+
+  AutoLock lock(&lock_);
+  if (cache_content_) {
+    if (cached_data_.empty()) {
+      Error error = DownloadToCache();
+      if (error)
+        return error;
+    }
+
+    return ReadPartialFromCache(offs, buf, count, out_bytes);
+  }
+
+  return DownloadPartial(offs, buf, count, out_bytes);
+}
+
+Error MountNodeHttp::FTruncate(off_t size) { return ENOSYS; }
+
+Error MountNodeHttp::Write(size_t offs,
+                           const void* buf,
+                           size_t count,
+                           int* out_bytes) {
+  // TODO(binji): support POST?
+  *out_bytes = 0;
+  return ENOSYS;
+}
+
+Error MountNodeHttp::GetSize(size_t* out_size) {
+  *out_size = 0;
+
+  // TODO(binji): This value should be cached properly; i.e. obey the caching
+  // headers returned by the server.
+  AutoLock lock(&lock_);
+  if (!has_cached_size_) {
+    // Even if DownloadToCache fails, the best result we can return is what
+    // was written to stat_.st_size.
+    if (cache_content_) {
+      Error error = DownloadToCache();
+      if (error)
+        return error;
+    }
+  }
+
+  *out_size = stat_.st_size;
+  return 0;
+}
+
+MountNodeHttp::MountNodeHttp(Mount* mount,
+                             const std::string& url,
+                             bool cache_content)
+    : MountNode(mount),
+      url_(url),
+      cache_content_(cache_content),
+      has_cached_size_(false) {}
+
+Error MountNodeHttp::OpenUrl(const char* method,
+                             StringMap_t* request_headers,
+                             PP_Resource* out_loader,
+                             PP_Resource* out_request,
+                             PP_Resource* out_response,
+                             int32_t* out_statuscode,
+                             StringMap_t* out_response_headers) {
+  // Assume lock_ is already held.
+  PepperInterface* ppapi = mount_->ppapi();
+
+  MountHttp* mount_http = static_cast<MountHttp*>(mount_);
+  ScopedResource request(
+      ppapi, mount_http->MakeUrlRequestInfo(url_, method, request_headers));
+  if (!request.pp_resource())
+    return EINVAL;
+
+  URLLoaderInterface* loader_interface = ppapi->GetURLLoaderInterface();
+  URLResponseInfoInterface* response_interface =
+      ppapi->GetURLResponseInfoInterface();
+  VarInterface* var_interface = ppapi->GetVarInterface();
+
+  ScopedResource loader(ppapi, loader_interface->Create(ppapi->GetInstance()));
+  if (!loader.pp_resource())
+    return EINVAL;
+
+  int32_t result = loader_interface->Open(
+      loader.pp_resource(), request.pp_resource(), PP_BlockUntilComplete());
+  if (result != PP_OK)
+    return PPErrorToErrno(result);
+
+  ScopedResource response(
+      ppapi, loader_interface->GetResponseInfo(loader.pp_resource()));
+  if (!response.pp_resource())
+    return EINVAL;
+
+  // Get response statuscode.
+  PP_Var statuscode = response_interface->GetProperty(
+      response.pp_resource(), PP_URLRESPONSEPROPERTY_STATUSCODE);
+
+  if (statuscode.type != PP_VARTYPE_INT32)
+    return EINVAL;
+
+  *out_statuscode = statuscode.value.as_int;
+
+  // Only accept OK or Partial Content.
+  if (*out_statuscode != STATUSCODE_OK &&
+      *out_statuscode != STATUSCODE_PARTIAL_CONTENT) {
+    return EINVAL;
+  }
+
+  // Get response headers.
+  PP_Var response_headers_var = response_interface->GetProperty(
+      response.pp_resource(), PP_URLRESPONSEPROPERTY_HEADERS);
+
+  uint32_t response_headers_length;
+  const char* response_headers_str =
+      var_interface->VarToUtf8(response_headers_var, &response_headers_length);
+
+  *out_loader = loader.Release();
+  *out_request = request.Release();
+  *out_response = response.Release();
+  *out_response_headers =
+      ParseHeaders(response_headers_str, response_headers_length);
+
+  return 0;
+}
+
+Error MountNodeHttp::DownloadToCache() {
+  StringMap_t headers;
+  PP_Resource loader;
+  PP_Resource request;
+  PP_Resource response;
+  int32_t statuscode;
+  StringMap_t response_headers;
+  Error error = OpenUrl("GET",
+                        &headers,
+                        &loader,
+                        &request,
+                        &response,
+                        &statuscode,
+                        &response_headers);
+  if (error)
+    return error;
+
+  PepperInterface* ppapi = mount_->ppapi();
+  ScopedResource scoped_loader(ppapi, loader);
+  ScopedResource scoped_request(ppapi, request);
+  ScopedResource scoped_response(ppapi, response);
+
+  size_t content_length = 0;
+  if (ParseContentLength(response_headers, &content_length)) {
+    cached_data_.resize(content_length);
+    int real_size;
+    error = DownloadToBuffer(
+        loader, cached_data_.data(), content_length, &real_size);
+    if (error)
+      return error;
+
+    SetCachedSize(real_size);
+    cached_data_.resize(real_size);
+    return 0;
+  }
+
+  // We don't know how big the file is. Read in chunks.
+  cached_data_.resize(MAX_READ_BUFFER_SIZE);
+  size_t total_bytes_read = 0;
+  size_t bytes_to_read = MAX_READ_BUFFER_SIZE;
+  while (true) {
+    char* buf = cached_data_.data() + total_bytes_read;
+    int bytes_read;
+    error = DownloadToBuffer(loader, buf, bytes_to_read, &bytes_read);
+    if (error)
+      return error;
+
+    total_bytes_read += bytes_read;
+
+    if (bytes_read < bytes_to_read) {
+      SetCachedSize(total_bytes_read);
+      cached_data_.resize(total_bytes_read);
+      return 0;
+    }
+
+    cached_data_.resize(total_bytes_read + bytes_to_read);
+  }
+}
+
+Error MountNodeHttp::ReadPartialFromCache(size_t offs,
+                                          void* buf,
+                                          size_t count,
+                                          int* out_bytes) {
+  *out_bytes = 0;
+
+  if (offs > cached_data_.size())
+    return EINVAL;
+
+  count = std::min(count, cached_data_.size() - offs);
+  memcpy(buf, &cached_data_.data()[offs], count);
+
+  *out_bytes = count;
+  return 0;
+}
+
+Error MountNodeHttp::DownloadPartial(size_t offs,
+                                     void* buf,
+                                     size_t count,
+                                     int* out_bytes) {
+  *out_bytes = 0;
+
+  StringMap_t headers;
+
+  char buffer[100];
+  // Range request is inclusive: 0-99 returns 100 bytes.
+  snprintf(&buffer[0],
+           sizeof(buffer),
+           "bytes=%" PRIuS "-%" PRIuS,
+           offs,
+           offs + count - 1);
+  headers["Range"] = buffer;
+
+  PP_Resource loader;
+  PP_Resource request;
+  PP_Resource response;
+  int32_t statuscode;
+  StringMap_t response_headers;
+  Error error = OpenUrl("GET",
+                        &headers,
+                        &loader,
+                        &request,
+                        &response,
+                        &statuscode,
+                        &response_headers);
+  if (error)
+    return error;
+
+  PepperInterface* ppapi = mount_->ppapi();
+  ScopedResource scoped_loader(ppapi, loader);
+  ScopedResource scoped_request(ppapi, request);
+  ScopedResource scoped_response(ppapi, response);
+
+  size_t read_start = 0;
+  if (statuscode == STATUSCODE_OK) {
+    // No partial result, read everything starting from the part we care about.
+    size_t content_length;
+    if (ParseContentLength(response_headers, &content_length)) {
+      if (offs >= content_length)
+        return EINVAL;
+
+      // Clamp count, if trying to read past the end of the file.
+      if (offs + count > content_length) {
+        count = content_length - offs;
+      }
+    }
+  } else if (statuscode == STATUSCODE_PARTIAL_CONTENT) {
+    // Determine from the headers where we are reading.
+    size_t read_end;
+    size_t entity_length;
+    if (ParseContentRange(
+            response_headers, &read_start, &read_end, &entity_length)) {
+      if (read_start > offs || read_start > read_end) {
+        // If this error occurs, the server is returning bogus values.
+        return EINVAL;
+      }
+
+      // Clamp count, if trying to read past the end of the file.
+      count = std::min(read_end - read_start, count);
+    } else {
+      // Partial Content without Content-Range. Assume that the server gave us
+      // exactly what we asked for. This can happen even when the server
+      // returns 200 -- the cache may return 206 in this case, but not modify
+      // the headers.
+      read_start = offs;
+    }
+  }
+
+  if (read_start < offs) {
+    // We aren't yet at the location where we want to start reading. Read into
+    // our dummy buffer until then.
+    size_t bytes_to_read = offs - read_start;
+    if (buffer_.size() < bytes_to_read)
+      buffer_.resize(std::min(bytes_to_read, MAX_READ_BUFFER_SIZE));
+
+    while (bytes_to_read > 0) {
+      int32_t bytes_read;
+      Error error =
+          DownloadToBuffer(loader, buffer_.data(), buffer_.size(), &bytes_read);
+      if (error)
+        return error;
+
+      bytes_to_read -= bytes_read;
+    }
+  }
+
+  return DownloadToBuffer(loader, buf, count, out_bytes);
+}
+
+Error MountNodeHttp::DownloadToBuffer(PP_Resource loader,
+                                      void* buf,
+                                      size_t count,
+                                      int* out_bytes) {
+  *out_bytes = 0;
+
+  PepperInterface* ppapi = mount_->ppapi();
+  URLLoaderInterface* loader_interface = ppapi->GetURLLoaderInterface();
+
+  char* out_buffer = static_cast<char*>(buf);
+  size_t bytes_to_read = count;
+  while (bytes_to_read > 0) {
+    int32_t bytes_read = loader_interface->ReadResponseBody(
+        loader, out_buffer, bytes_to_read, PP_BlockUntilComplete());
+
+    if (bytes_read == 0) {
+      // This is not an error -- it may just be that we were trying to read
+      // more data than exists.
+      *out_bytes = count - bytes_to_read;
+      return 0;
+    }
+
+    if (bytes_read < 0)
+      return PPErrorToErrno(bytes_read);
+
+    assert(bytes_read <= bytes_to_read);
+    bytes_to_read -= bytes_read;
+    out_buffer += bytes_read;
+  }
+
+  *out_bytes = count;
+  return 0;
+}
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_http.h b/native_client_sdk/src/libraries/nacl_io/mount_node_http.h
new file mode 100644
index 0000000000..6b174681d1
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_http.h
@@ -0,0 +1,70 @@
+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef LIBRARIES_NACL_IO_MOUNT_NODE_HTTP_H_
+#define LIBRARIES_NACL_IO_MOUNT_NODE_HTTP_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "nacl_io/error.h"
+#include "nacl_io/mount_node.h"
+#include "nacl_io/pepper_interface.h"
+
+typedef std::map<std::string, std::string> StringMap_t;
+
+class MountNodeHttp : public MountNode {
+ public:
+  virtual Error FSync();
+  virtual Error GetDents(size_t offs,
+                         struct dirent* pdir,
+                         size_t count,
+                         int* out_bytes);
+  virtual Error GetStat(struct stat* stat);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error FTruncate(off_t size);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
+  virtual Error GetSize(size_t* out_size);
+
+  void SetCachedSize(off_t size);
+
+ protected:
+  MountNodeHttp(Mount* mount, const std::string& url, bool cache_content);
+
+ private:
+  Error OpenUrl(const char* method,
+                StringMap_t* request_headers,
+                PP_Resource* out_loader,
+                PP_Resource* out_request,
+                PP_Resource* out_response,
+                int32_t* out_statuscode,
+                StringMap_t* out_response_headers);
+
+  Error DownloadToCache();
+  Error ReadPartialFromCache(size_t offs,
+                             void* buf,
+                             size_t count,
+                             int* out_bytes);
+  Error DownloadPartial(size_t offs, void* buf, size_t count, int* out_bytes);
+  Error DownloadToBuffer(PP_Resource loader,
+                         void* buf,
+                         size_t count,
+                         int* out_bytes);
+
+  std::string url_;
+  std::vector<char> buffer_;
+
+  bool cache_content_;
+  bool has_cached_size_;
+  std::vector<char> cached_data_;
+
+  friend class MountHttp;
+};
+
+#endif  // LIBRARIES_NACL_IO_MOUNT_NODE_HTTP_H_
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_mem.cc b/native_client_sdk/src/libraries/nacl_io/mount_node_mem.cc
index 0fa82baeba..d324079700 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_mem.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_mem.cc
@@ -8,74 +8,88 @@
 #include <string.h>
 
 #include "nacl_io/osstat.h"
-#include "utils/auto_lock.h"
+#include "sdk_util/auto_lock.h"
 
 #define BLOCK_SIZE (1 << 16)
 #define BLOCK_MASK (BLOCK_SIZE - 1)
 
-MountNodeMem::MountNodeMem(Mount *mount)
-    : MountNode(mount),
-      data_(NULL),
-      capacity_(0) {
+MountNodeMem::MountNodeMem(Mount* mount)
+    : MountNode(mount), data_(NULL), capacity_(0) {
   stat_.st_mode |= S_IFREG;
 }
 
-MountNodeMem::~MountNodeMem() {
-  free(data_);
-}
+MountNodeMem::~MountNodeMem() { free(data_); }
+
+Error MountNodeMem::Read(size_t offs, void* buf, size_t count, int* out_bytes) {
+  *out_bytes = 0;
 
-int MountNodeMem::Read(size_t offs, void *buf, size_t count) {
   AutoLock lock(&lock_);
-  if (count == 0) return 0;
-  if (offs + count > GetSize()) {
-    count = GetSize() - offs;
+  if (count == 0)
+    return 0;
+
+  size_t size = stat_.st_size;
+
+  if (offs + count > size) {
+    count = size - offs;
   }
 
   memcpy(buf, &data_[offs], count);
-  return static_cast<int>(count);
+  *out_bytes = static_cast<int>(count);
+  return 0;
 }
 
-int MountNodeMem::Write(size_t offs, const void *buf, size_t count) {
+Error MountNodeMem::Write(size_t offs,
+                          const void* buf,
+                          size_t count,
+                          int* out_bytes) {
+  *out_bytes = 0;
+
   AutoLock lock(&lock_);
 
-  if (count == 0) return 0;
+  if (count == 0)
+    return 0;
+
+  if (count + offs > stat_.st_size) {
+    Error error = FTruncate(count + offs);
+    if (error)
+      return error;
 
-  if (count + offs > GetSize()) {
-    FTruncate(count + offs);
-    count = GetSize() - offs;
+    count = stat_.st_size - offs;
   }
 
   memcpy(&data_[offs], buf, count);
-  return static_cast<int>(count);
+  *out_bytes = static_cast<int>(count);
+  return 0;
 }
 
-int MountNodeMem::FTruncate(off_t size) {
-  size_t need = (size + BLOCK_MASK) & ~BLOCK_MASK;
+Error MountNodeMem::FTruncate(off_t new_size) {
+  size_t need = (new_size + BLOCK_MASK) & ~BLOCK_MASK;
+  size_t old_size = stat_.st_size;
 
   // If the current capacity is correct, just adjust and return
   if (need == capacity_) {
-    stat_.st_size = static_cast<off_t>(size);
+    stat_.st_size = static_cast<off_t>(new_size);
     return 0;
   }
 
   // Attempt to realloc the block
-  char *newdata = static_cast<char *>(realloc(data_, need));
+  char* newdata = static_cast<char*>(realloc(data_, need));
   if (newdata != NULL) {
     // Zero out new space.
-    if (size > GetSize())
-      memset(newdata + GetSize(), 0, size - GetSize());
+    if (new_size > old_size)
+      memset(newdata + old_size, 0, new_size - old_size);
 
     data_ = newdata;
     capacity_ = need;
-    stat_.st_size = static_cast<off_t>(size);
+    stat_.st_size = static_cast<off_t>(new_size);
     return 0;
   }
 
   // If we failed, then adjust size according to what we keep
-  if (size > capacity_) size = capacity_;
+  if (new_size > capacity_)
+    new_size = capacity_;
 
   // Update the size and return the new size
-  stat_.st_size = static_cast<off_t>(size);
-  errno = EIO;
-  return -1;
+  stat_.st_size = static_cast<off_t>(new_size);
+  return EIO;
 }
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h b/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h
index 07acfe16d7..6457014293 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h
@@ -16,9 +16,12 @@ class MountNodeMem : public MountNode {
 
  public:
   // Normal read/write operations on a file
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int Write(size_t offs, const void* buf, size_t count);
-  virtual int FTruncate(off_t size);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
+  virtual Error FTruncate(off_t size);
 
  private:
   char* data_;
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_passthrough.cc b/native_client_sdk/src/libraries/nacl_io/mount_passthrough.cc
index 82660d68ea..268cbea7a5 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_passthrough.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_passthrough.cc
@@ -9,14 +9,10 @@
 class MountNodePassthrough : public MountNode {
  public:
   explicit MountNodePassthrough(Mount* mount, int real_fd)
-    : MountNode(mount),
-      real_fd_(real_fd) {
-  }
+      : MountNode(mount), real_fd_(real_fd) {}
 
  protected:
-  virtual bool Init(int flags) {
-    return true;
-  }
+  virtual Error Init(int flags) { return 0; }
 
   virtual void Destroy() {
     if (real_fd_)
@@ -26,77 +22,74 @@ class MountNodePassthrough : public MountNode {
 
  public:
   // Normal read/write operations on a file
-  virtual int Read(size_t offs, void* buf, size_t count) {
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes) {
+    *out_bytes = 0;
+
     off_t new_offset;
     int err = _real_lseek(real_fd_, offs, 0, &new_offset);
-    if (err) {
-      errno = err;
-      return -1;
-    }
+    if (err)
+      return err;
 
     size_t nread;
     err = _real_read(real_fd_, buf, count, &nread);
-    if (err) {
-      errno = err;
-      return -1;
-    }
+    if (err)
+      return err;
 
-    return static_cast<int>(nread);
+    *out_bytes = static_cast<int>(nread);
+    return 0;
   }
 
-  virtual int Write(size_t offs, const void* buf, size_t count) {
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes) {
+    *out_bytes = 0;
+
     off_t new_offset;
     int err = _real_lseek(real_fd_, offs, 0, &new_offset);
-    if (err) {
-      errno = err;
-      return -1;
-    }
+    if (err)
+      return err;
 
     size_t nwrote;
     err = _real_write(real_fd_, buf, count, &nwrote);
-    if (err) {
-      errno = err;
-      return -1;
-    }
+    if (err)
+      return err;
 
-    return static_cast<int>(nwrote);
+    *out_bytes = static_cast<int>(nwrote);
+    return 0;
   }
 
-  virtual int FTruncate(off_t size) {
+  virtual Error FTruncate(off_t size) {
     // TODO(binji): what to do here?
-    return -1;
+    return ENOSYS;
   }
 
-  virtual int GetDents(size_t offs, struct dirent* pdir, size_t count) {
+  virtual Error GetDents(size_t offs, struct dirent* pdir, size_t count) {
     size_t nread;
     int err = _real_getdents(real_fd_, pdir, count, &nread);
-    if (err) {
-      errno = err;
-      return -1;
-    }
-
+    if (err)
+      return err;
     return nread;
   }
 
-  virtual int GetStat(struct stat* stat) {
+  virtual Error GetStat(struct stat* stat) {
     int err = _real_fstat(real_fd_, stat);
-    if (err) {
-      errno = err;
-      return -1;
-    }
-
+    if (err)
+      return err;
     return 0;
   }
 
-  void* MMap(void* addr, size_t length, int prot, int flags, size_t offset) {
-    void* new_addr = addr;
-    int err = _real_mmap(&new_addr, length, prot, flags, real_fd_, offset);
-    if (err) {
-      errno = err;
-      return (void*)-1;
-    }
-
-    return new_addr;
+  Error MMap(void* addr,
+             size_t length,
+             int prot,
+             int flags,
+             size_t offset,
+             void** out_addr) {
+    *out_addr = addr;
+    int err = _real_mmap(out_addr, length, prot, flags, real_fd_, offset);
+    if (err)
+      return err;
+    return 0;
   }
 
  private:
@@ -105,70 +98,56 @@ class MountNodePassthrough : public MountNode {
   int real_fd_;
 };
 
-MountPassthrough::MountPassthrough() {
-}
+MountPassthrough::MountPassthrough() {}
 
-bool MountPassthrough::Init(int dev, StringMap_t& args,
-                            PepperInterface* ppapi) {
-  Mount::Init(dev, args, ppapi);
-  return true;
+Error MountPassthrough::Init(int dev,
+                             StringMap_t& args,
+                             PepperInterface* ppapi) {
+  return Mount::Init(dev, args, ppapi);
 }
 
-void MountPassthrough::Destroy() {
-}
+void MountPassthrough::Destroy() {}
+
+Error MountPassthrough::Open(const Path& path, int mode, MountNode** out_node) {
+  *out_node = NULL;
 
-MountNode *MountPassthrough::Open(const Path& path, int mode) {
   int real_fd;
-  int err = _real_open(path.Join().c_str(), mode, 0666, &real_fd);
-  if (err) {
-    errno = err;
-    return NULL;
-  }
+  int error = _real_open(path.Join().c_str(), mode, 0666, &real_fd);
+  if (error)
+    return error;
 
   MountNodePassthrough* node = new MountNodePassthrough(this, real_fd);
-  return node;
+  *out_node = node;
+  return 0;
 }
 
-MountNode *MountPassthrough::OpenResource(const Path& path) {
+Error MountPassthrough::OpenResource(const Path& path, MountNode** out_node) {
+  *out_node = NULL;
+
   int real_fd;
-  int err = _real_open_resource(path.Join().c_str(), &real_fd);
-  if (err) {
-    errno = err;
-    return NULL;
-  }
+  int error = _real_open_resource(path.Join().c_str(), &real_fd);
+  if (error)
+    return error;
 
   MountNodePassthrough* node = new MountNodePassthrough(this, real_fd);
-  return node;
+  *out_node = node;
+  return 0;
 }
 
-int MountPassthrough::Unlink(const Path& path) {
+Error MountPassthrough::Unlink(const Path& path) {
   // Not implemented by NaCl.
-  errno = ENOSYS;
-  return -1;
+  return ENOSYS;
 }
 
-int MountPassthrough::Mkdir(const Path& path, int perm) {
-  int err = _real_mkdir(path.Join().c_str(), perm);
-  if (err) {
-    errno = err;
-    return -1;
-  }
-
-  return 0;
+Error MountPassthrough::Mkdir(const Path& path, int perm) {
+  return _real_mkdir(path.Join().c_str(), perm);
 }
 
-int MountPassthrough::Rmdir(const Path& path) {
-  int err = _real_rmdir(path.Join().c_str());
-  if (err) {
-    errno = err;
-    return -1;
-  }
-
-  return 0;
+Error MountPassthrough::Rmdir(const Path& path) {
+  return _real_rmdir(path.Join().c_str());
 }
 
-int MountPassthrough::Remove(const Path& path) {
+Error MountPassthrough::Remove(const Path& path) {
   // Not implemented by NaCl.
-  errno = ENOSYS;
-  return -1;
+  return ENOSYS;
 }
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h b/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h
index 00a0eec98f..b143abf007 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_passthrough.h
@@ -11,16 +11,16 @@ class MountPassthrough : public Mount {
  protected:
   MountPassthrough();
 
-  virtual bool Init(int dev, StringMap_t& args, PepperInterface* ppapi);
+  virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi);
   virtual void Destroy();
 
  public:
-  virtual MountNode *Open(const Path& path, int mode);
-  virtual MountNode *OpenResource(const Path& path);
-  virtual int Unlink(const Path& path);
-  virtual int Mkdir(const Path& path, int perm);
-  virtual int Rmdir(const Path& path);
-  virtual int Remove(const Path& path);
+  virtual Error Open(const Path& path, int mode, MountNode** out_node);
+  virtual Error OpenResource(const Path& path, MountNode** out_node);
+  virtual Error Unlink(const Path& path);
+  virtual Error Mkdir(const Path& path, int perm);
+  virtual Error Rmdir(const Path& path);
+  virtual Error Remove(const Path& path);
 
 private:
   friend class Mount;
diff --git a/native_client_sdk/src/libraries/nacl_io/nacl_io.h b/native_client_sdk/src/libraries/nacl_io/nacl_io.h
index f9343538ca..b408bb9385 100644
--- a/native_client_sdk/src/libraries/nacl_io/nacl_io.h
+++ b/native_client_sdk/src/libraries/nacl_io/nacl_io.h
@@ -9,7 +9,7 @@
 #include <ppapi/c/ppb.h>
 
 #include "nacl_io/kernel_wrap.h"
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 EXTERN_C_BEGIN
 
diff --git a/native_client_sdk/src/libraries/nacl_io/nacl_mounts.vcproj b/native_client_sdk/src/libraries/nacl_io/nacl_mounts.vcproj
index 875a16f99f..d57c84fbaa 100644
--- a/native_client_sdk/src/libraries/nacl_io/nacl_mounts.vcproj
+++ b/native_client_sdk/src/libraries/nacl_io/nacl_mounts.vcproj
@@ -41,7 +41,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="0"
-				AdditionalIncludeDirectories="../win;../utils"
+				AdditionalIncludeDirectories="../win;../sdk_util"
 				PreprocessorDefinitions="WIN32;_DEBUG;_LIB"
 				MinimalRebuild="true"
 				BasicRuntimeChecks="3"
diff --git a/native_client_sdk/src/libraries/nacl_io/osdirent.h b/native_client_sdk/src/libraries/nacl_io/osdirent.h
index 22dcd616f9..39a3b957bb 100644
--- a/native_client_sdk/src/libraries/nacl_io/osdirent.h
+++ b/native_client_sdk/src/libraries/nacl_io/osdirent.h
@@ -8,7 +8,7 @@
 #if defined(WIN32)
 
 #include <sys/types.h>
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 struct dirent {
   _ino_t d_ino;
diff --git a/native_client_sdk/src/libraries/nacl_io/path.h b/native_client_sdk/src/libraries/nacl_io/path.h
index 7ac41f2f25..fcbaa33d67 100644
--- a/native_client_sdk/src/libraries/nacl_io/path.h
+++ b/native_client_sdk/src/libraries/nacl_io/path.h
@@ -8,7 +8,7 @@
 #include <string>
 #include <vector>
 
-#include "utils/macros.h"
+#include "sdk_util/macros.h"
 
 typedef std::vector<std::string> StringArray_t;
 
diff --git a/native_client_sdk/src/libraries/nacl_io/pepper/all_interfaces.h b/native_client_sdk/src/libraries/nacl_io/pepper/all_interfaces.h
index 679573607d..5bab3b23c4 100644
--- a/native_client_sdk/src/libraries/nacl_io/pepper/all_interfaces.h
+++ b/native_client_sdk/src/libraries/nacl_io/pepper/all_interfaces.h
@@ -39,12 +39,14 @@ BEGIN_INTERFACE(FileIoInterface, PPB_FileIO, PPB_FILEIO_INTERFACE_1_0)
           const char*, int32_t, PP_CompletionCallback)
 END_INTERFACE(FileIoInterface, PPB_FileIO)
 
-BEGIN_INTERFACE(FileRefInterface, PPB_FileRef, PPB_FILEREF_INTERFACE_1_0)
+BEGIN_INTERFACE(FileRefInterface, PPB_FileRef, PPB_FILEREF_INTERFACE_1_1)
   METHOD2(FileRefInterface, PP_Resource, Create, PP_Resource, const char*)
   METHOD2(FileRefInterface, int32_t, Delete, PP_Resource, PP_CompletionCallback)
   METHOD1(FileRefInterface, PP_Var, GetName, PP_Resource)
   METHOD3(FileRefInterface, int32_t, MakeDirectory, PP_Resource, PP_Bool,
           PP_CompletionCallback)
+  METHOD3(FileRefInterface, int32_t, Query, PP_Resource, PP_FileInfo*,
+          PP_CompletionCallback)
   METHOD3(FileRefInterface, int32_t, ReadDirectoryEntries, PP_Resource,
           const PP_ArrayOutput&, PP_CompletionCallback)
 END_INTERFACE(FileRefInterface, PPB_FileRef)
diff --git a/native_client_sdk/src/libraries/nacl_io/pepper_interface.h b/native_client_sdk/src/libraries/nacl_io/pepper_interface.h
index 512fd6fdbf..31915a4e76 100644
--- a/native_client_sdk/src/libraries/nacl_io/pepper_interface.h
+++ b/native_client_sdk/src/libraries/nacl_io/pepper_interface.h
@@ -21,7 +21,7 @@
 #include <ppapi/c/ppb_url_response_info.h>
 #include <ppapi/c/ppb_var.h>
 
-#include <utils/macros.h>
+#include <sdk_util/macros.h>
 
 // Note: To add a new interface:
 //
diff --git a/native_client_sdk/src/libraries/nacl_io_test/example.dsc b/native_client_sdk/src/libraries/nacl_io_test/example.dsc
index a47ed63744..df934a56a2 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/example.dsc
+++ b/native_client_sdk/src/libraries/nacl_io_test/example.dsc
@@ -1,5 +1,4 @@
 {
-  # TODO(binji): pnacl doesn't build right now because gtest doesn't build yet.
   'TOOLS': ['newlib', 'glibc', 'pnacl', 'win'],
 
   # Need to add ../../examples for common.js
diff --git a/native_client_sdk/src/libraries/nacl_io_test/kernel_object_test.cc b/native_client_sdk/src/libraries/nacl_io_test/kernel_object_test.cc
index 268c6f51a6..9e6f4832a7 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/kernel_object_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/kernel_object_test.cc
@@ -23,22 +23,21 @@ namespace {
 class MountRefMock : public Mount {
  public:
   MountRefMock(int* mount_count, int* handle_count)
-      : mount_count(mount_count),
-        handle_count(handle_count) {
+      : mount_count(mount_count), handle_count(handle_count) {
     (*mount_count)++;
   }
 
-  ~MountRefMock() {
-    (*mount_count)--;
-  }
+  ~MountRefMock() { (*mount_count)--; }
 
  public:
-  MountNode* Open(const Path& path, int mode) { return NULL; }
-  int Close(MountNode* node) { return 0; }
-  int Unlink(const Path& path) { return 0; }
-  int Mkdir(const Path& path, int permissions) { return 0; }
-  int Rmdir(const Path& path) { return 0; }
-  int Remove(const Path& path) { return 0; }
+  Error Open(const Path& path, int mode, MountNode** out_node) {
+    *out_node = NULL;
+    return ENOSYS;
+  }
+  Error Unlink(const Path& path) { return 0; }
+  Error Mkdir(const Path& path, int permissions) { return 0; }
+  Error Rmdir(const Path& path) { return 0; }
+  Error Remove(const Path& path) { return 0; }
 
  public:
   int* mount_count;
@@ -47,8 +46,8 @@ class MountRefMock : public Mount {
 
 class KernelHandleRefMock : public KernelHandle {
  public:
-  KernelHandleRefMock(Mount* mnt, MountNode* node, int flags)
-      : KernelHandle(mnt, node, flags) {
+  KernelHandleRefMock(Mount* mnt, MountNode* node)
+      : KernelHandle(mnt, node) {
     MountRefMock* mock_mount = static_cast<MountRefMock*>(mnt);
     (*mock_mount->handle_count)++;
   }
@@ -61,9 +60,7 @@ class KernelHandleRefMock : public KernelHandle {
 
 class KernelObjectTest : public ::testing::Test {
  public:
-  KernelObjectTest()
-      : mount_count(0),
-        handle_count(0) {
+  KernelObjectTest() : mount_count(0), handle_count(0) {
     proxy = new KernelObject;
     mnt = new MountRefMock(&mount_count, &handle_count);
   }
@@ -81,10 +78,10 @@ class KernelObjectTest : public ::testing::Test {
 
 }  // namespace
 
-
 TEST_F(KernelObjectTest, Referencing) {
-  KernelHandle* handle = new KernelHandleRefMock(mnt, NULL, 0);
-  KernelHandle* handle2 = new KernelHandleRefMock(mnt, NULL, 0);
+  KernelHandle* handle = new KernelHandleRefMock(mnt, NULL);
+  KernelHandle* handle2 = new KernelHandleRefMock(mnt, NULL);
+  KernelHandle* result_handle = NULL;
 
   // Objects should have one ref when we start
   EXPECT_EQ(1, mnt->RefCount());
@@ -111,14 +108,16 @@ TEST_F(KernelObjectTest, Referencing) {
   EXPECT_EQ(2, fd3);
 
   // We should find the handle by either fd
-  EXPECT_EQ(handle, proxy->AcquireHandle(fd1));
-  EXPECT_EQ(handle, proxy->AcquireHandle(fd2));
+  EXPECT_EQ(0, proxy->AcquireHandle(fd1, &result_handle));
+  EXPECT_EQ(handle, result_handle);
+  EXPECT_EQ(0, proxy->AcquireHandle(fd2, &result_handle));
+  EXPECT_EQ(handle, result_handle);
 
   // A non existent fd should fail
-  EXPECT_EQ(NULL, proxy->AcquireHandle(-1));
-  EXPECT_EQ(EBADF, errno);
-  EXPECT_EQ(NULL, proxy->AcquireHandle(100));
-  EXPECT_EQ(EBADF, errno);
+  EXPECT_EQ(EBADF, proxy->AcquireHandle(-1, &result_handle));
+  EXPECT_EQ(NULL, result_handle);
+  EXPECT_EQ(EBADF, proxy->AcquireHandle(100, &result_handle));
+  EXPECT_EQ(NULL, result_handle);
 
   // Acquiring the handle, should have ref'd it
   EXPECT_EQ(4, mnt->RefCount());
@@ -155,27 +154,35 @@ TEST_F(KernelObjectTest, Referencing) {
 }
 
 TEST_F(KernelObjectTest, FreeAndReassignFD) {
+  KernelHandle* result_handle = NULL;
+
   EXPECT_EQ(0, handle_count);
 
-  KernelHandle* handle = new KernelHandleRefMock(mnt, NULL, 0);
+  KernelHandle* handle = new KernelHandleRefMock(mnt, NULL);
 
   EXPECT_EQ(1, handle_count);
   EXPECT_EQ(1, handle->RefCount());
 
   // Assign to a non-existent FD
   proxy->FreeAndReassignFD(2, handle);
-  EXPECT_EQ((KernelHandle*)NULL, proxy->AcquireHandle(0));
-  EXPECT_EQ((KernelHandle*)NULL, proxy->AcquireHandle(1));
-  EXPECT_EQ(handle, proxy->AcquireHandle(2));
+  EXPECT_EQ(EBADF, proxy->AcquireHandle(0, &result_handle));
+  EXPECT_EQ(NULL, result_handle);
+  EXPECT_EQ(EBADF, proxy->AcquireHandle(1, &result_handle));
+  EXPECT_EQ(NULL, result_handle);
+  EXPECT_EQ(0, proxy->AcquireHandle(2, &result_handle));
+  EXPECT_EQ(handle, result_handle);
   proxy->ReleaseHandle(handle);
 
   EXPECT_EQ(1, handle_count);
   EXPECT_EQ(2, handle->RefCount());
 
   proxy->FreeAndReassignFD(0, handle);
-  EXPECT_EQ(handle, proxy->AcquireHandle(0));
-  EXPECT_EQ((KernelHandle*)NULL, proxy->AcquireHandle(1));
-  EXPECT_EQ(handle, proxy->AcquireHandle(2));
+  EXPECT_EQ(0, proxy->AcquireHandle(0, &result_handle));
+  EXPECT_EQ(handle, result_handle);
+  EXPECT_EQ(EBADF, proxy->AcquireHandle(1, &result_handle));
+  EXPECT_EQ(NULL, result_handle);
+  EXPECT_EQ(0, proxy->AcquireHandle(2, &result_handle));
+  EXPECT_EQ(handle, result_handle);
   proxy->ReleaseHandle(handle);
   proxy->ReleaseHandle(handle);
 
diff --git a/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc b/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc
index d6816535e4..40f4ef7a15 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/kernel_proxy_test.cc
@@ -21,11 +21,9 @@
 
 #include "gtest/gtest.h"
 
-
 class KernelProxyTest : public ::testing::Test {
  public:
-  KernelProxyTest()
-      : kp_(new KernelProxy) {
+  KernelProxyTest() : kp_(new KernelProxy) {
     ki_init(kp_);
     // Unmount the passthrough FS and mount a memfs.
     EXPECT_EQ(0, kp_->umount("/"));
@@ -41,7 +39,6 @@ class KernelProxyTest : public ::testing::Test {
   KernelProxy* kp_;
 };
 
-
 TEST_F(KernelProxyTest, WorkingDirectory) {
   char text[1024];
 
@@ -50,7 +47,7 @@ TEST_F(KernelProxyTest, WorkingDirectory) {
   EXPECT_STREQ("/", text);
 
   char* alloc = ki_getwd(NULL);
-  EXPECT_EQ((char *) NULL, alloc);
+  EXPECT_EQ((char*)NULL, alloc);
   EXPECT_EQ(EFAULT, errno);
 
   text[0] = 0;
@@ -113,7 +110,8 @@ TEST_F(KernelProxyTest, MemMountIO) {
   EXPECT_NE(-1, fd3);
 
   len = ki_read(fd3, text, sizeof(text));
-  if (len > -0) text[len] = 0;
+  if (len > 0)
+    text[len] = 0;
   EXPECT_EQ(5, len);
   EXPECT_STREQ("HELLO", text);
   EXPECT_EQ(0, ki_close(fd1));
@@ -124,7 +122,8 @@ TEST_F(KernelProxyTest, MemMountIO) {
   EXPECT_EQ(5, ki_write(fd1, "WORLD", 5));
 
   len = ki_read(fd3, text, sizeof(text));
-  if (len >= 0) text[len] = 0;
+  if (len >= 0)
+    text[len] = 0;
 
   EXPECT_EQ(5, len);
   EXPECT_STREQ("WORLD", text);
@@ -132,7 +131,8 @@ TEST_F(KernelProxyTest, MemMountIO) {
   fd2 = ki_open("/foo/bar", O_RDONLY);
   EXPECT_NE(-1, fd2);
   len = ki_read(fd2, text, sizeof(text));
-  if (len > 0) text[len] = 0;
+  if (len > 0)
+    text[len] = 0;
   EXPECT_EQ(10, len);
   EXPECT_STREQ("HELLOWORLD", text);
 }
@@ -197,17 +197,17 @@ TEST_F(KernelProxyTest, MemMountDup) {
   // fd, new_fd, dup_fd -> "/bar"
 }
 
-
 StringMap_t g_StringMap;
 
 class MountMockInit : public MountMem {
  public:
-  virtual bool Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
+  virtual Error Init(int dev, StringMap_t& args, PepperInterface* ppapi) {
     g_StringMap = args;
     if (args.find("false") != args.end())
-      return false;
-    return true;
-  };
+      return EINVAL;
+    return 0;
+  }
+  ;
 };
 
 class KernelProxyMountMock : public KernelProxy {
@@ -219,10 +219,7 @@ class KernelProxyMountMock : public KernelProxy {
 
 class KernelProxyMountTest : public ::testing::Test {
  public:
-  KernelProxyMountTest()
-      : kp_(new KernelProxyMountMock) {
-    ki_init(kp_);
-  }
+  KernelProxyMountTest() : kp_(new KernelProxyMountMock) { ki_init(kp_); }
 
   ~KernelProxyMountTest() {
     ki_uninit();
@@ -245,28 +242,38 @@ TEST_F(KernelProxyMountTest, MountInit) {
   EXPECT_EQ("y", g_StringMap["x"]);
 }
 
-
 namespace {
 
 int g_MMapCount = 0;
 
 class MountNodeMockMMap : public MountNode {
  public:
-  MountNodeMockMMap(Mount* mount)
-      : MountNode(mount),
-        node_mmap_count_(0) {
-    Init(0);
+  MountNodeMockMMap(Mount* mount) : MountNode(mount), node_mmap_count_(0) {
+    EXPECT_EQ(0, Init(0));
   }
 
-  virtual void* MMap(void* addr, size_t length, int prot, int flags,
-                     size_t offset) {
+  virtual Error MMap(void* addr,
+                     size_t length,
+                     int prot,
+                     int flags,
+                     size_t offset,
+                     void** out_addr) {
     node_mmap_count_++;
     switch (g_MMapCount++) {
-      case 0: return reinterpret_cast<void*>(0x1000);
-      case 1: return reinterpret_cast<void*>(0x2000);
-      case 2: return reinterpret_cast<void*>(0x3000);
-      default: return MAP_FAILED;
+      case 0:
+        *out_addr = reinterpret_cast<void*>(0x1000);
+        break;
+      case 1:
+        *out_addr = reinterpret_cast<void*>(0x2000);
+        break;
+      case 2:
+        *out_addr = reinterpret_cast<void*>(0x3000);
+        break;
+      default:
+        return EPERM;
     }
+
+    return 0;
   }
 
  private:
@@ -275,16 +282,20 @@ class MountNodeMockMMap : public MountNode {
 
 class MountMockMMap : public Mount {
  public:
-  virtual MountNode* Open(const Path& path, int mode) {
+  virtual Error Open(const Path& path, int mode, MountNode** out_node) {
     MountNodeMockMMap* node = new MountNodeMockMMap(this);
-    return node;
+    *out_node = node;
+    return 0;
   }
 
-  virtual MountNode* OpenResource(const Path& path) { return NULL; }
-  virtual int Unlink(const Path& path) { return -1; }
-  virtual int Mkdir(const Path& path, int permissions) { return -1; }
-  virtual int Rmdir(const Path& path) { return -1; }
-  virtual int Remove(const Path& path) { return -1; }
+  virtual Error OpenResource(const Path& path, MountNode** out_node) {
+    *out_node = NULL;
+    return ENOSYS;
+  }
+  virtual Error Unlink(const Path& path) { return ENOSYS; }
+  virtual Error Mkdir(const Path& path, int permissions) { return ENOSYS; }
+  virtual Error Rmdir(const Path& path) { return ENOSYS; }
+  virtual Error Remove(const Path& path) { return ENOSYS; }
 };
 
 class KernelProxyMockMMap : public KernelProxy {
@@ -296,10 +307,7 @@ class KernelProxyMockMMap : public KernelProxy {
 
 class KernelProxyMMapTest : public ::testing::Test {
  public:
-  KernelProxyMMapTest()
-      : kp_(new KernelProxyMockMMap) {
-    ki_init(kp_);
-  }
+  KernelProxyMMapTest() : kp_(new KernelProxyMockMMap) { ki_init(kp_); }
 
   ~KernelProxyMMapTest() {
     ki_uninit();
diff --git a/native_client_sdk/src/libraries/nacl_io_test/kernel_wrap_test.cc b/native_client_sdk/src/libraries/nacl_io_test/kernel_wrap_test.cc
index f6f010c84d..34d8472ff2 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/kernel_wrap_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/kernel_wrap_test.cc
@@ -81,6 +81,10 @@ class KernelWrapTest : public ::testing::Test {
       .WillOnce(Return(0))
       .WillOnce(Return(1))
       .WillOnce(Return(2));
+    // And will call mount / and /dev.
+    EXPECT_CALL(mock, mount(_, _, _, _, _))
+      .WillOnce(Return(0))
+      .WillOnce(Return(0));
 
     ki_init(&mock);
   }
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_html5fs_test.cc b/native_client_sdk/src/libraries/nacl_io_test/mount_html5fs_test.cc
index ce3ab2d3c9..e92a20aa5d 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/mount_html5fs_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_html5fs_test.cc
@@ -3,6 +3,7 @@
  * found in the LICENSE file.
  */
 
+#include <errno.h>
 #include <fcntl.h>
 #include <string.h>
 #include <gmock/gmock.h>
@@ -93,7 +94,7 @@ class MountHtml5FsNodeTest : public MountHtml5FsTest {
   virtual void SetUp();
   virtual void TearDown();
 
-  void SetUpNodeExpectations();
+  void SetUpNodeExpectations(PP_FileType file_type);
   void InitFilesystem();
   void InitNode();
 
@@ -131,22 +132,32 @@ void MountHtml5FsNodeTest::TearDown() {
   }
 }
 
-void MountHtml5FsNodeTest::SetUpNodeExpectations() {
+void MountHtml5FsNodeTest::SetUpNodeExpectations(PP_FileType file_type) {
   // Open.
   EXPECT_CALL(*fileref_, Create(filesystem_resource_, StrEq(&path_[0])))
       .WillOnce(Return(fileref_resource_));
-  EXPECT_CALL(*fileio_, Create(instance_)).WillOnce(Return(fileio_resource_));
-  int32_t open_flags = PP_FILEOPENFLAG_READ | PP_FILEOPENFLAG_WRITE |
-      PP_FILEOPENFLAG_CREATE;
-  EXPECT_CALL(*fileio_,
-              Open(fileio_resource_, fileref_resource_, open_flags, _))
-      .WillOnce(Return(int32_t(PP_OK)));
+  PP_FileInfo info;
+  memset(&info, 0, sizeof(PP_FileInfo));
+  info.type = file_type;
+  EXPECT_CALL(*fileref_, Query(fileref_resource_, _, _))
+      .WillOnce(DoAll(SetArgPointee<1>(info),
+                      Return(int32_t(PP_OK))));
+  if (file_type != PP_FILETYPE_DIRECTORY) {
+    EXPECT_CALL(*fileio_, Create(instance_)).WillOnce(Return(fileio_resource_));
+    int32_t open_flags = PP_FILEOPENFLAG_READ | PP_FILEOPENFLAG_WRITE |
+        PP_FILEOPENFLAG_CREATE;
+    EXPECT_CALL(*fileio_,
+                Open(fileio_resource_, fileref_resource_, open_flags, _))
+        .WillOnce(Return(int32_t(PP_OK)));
+
+    // Close.
+    EXPECT_CALL(*fileio_, Close(fileio_resource_));
+    EXPECT_CALL(*ppapi_, ReleaseResource(fileio_resource_));
+    EXPECT_CALL(*fileio_, Flush(fileio_resource_, _));
+  }
 
   // Close.
-  EXPECT_CALL(*fileio_, Close(fileio_resource_));
   EXPECT_CALL(*ppapi_, ReleaseResource(fileref_resource_));
-  EXPECT_CALL(*ppapi_, ReleaseResource(fileio_resource_));
-  EXPECT_CALL(*fileio_, Flush(fileio_resource_, _));
 }
 
 void MountHtml5FsNodeTest::InitFilesystem() {
@@ -155,7 +166,7 @@ void MountHtml5FsNodeTest::InitFilesystem() {
 }
 
 void MountHtml5FsNodeTest::InitNode() {
-  node_ = mnt_->Open(Path(path_), O_CREAT | O_RDWR);
+  ASSERT_EQ(0, mnt_->Open(Path(path_), O_CREAT | O_RDWR, &node_));
   ASSERT_NE((MountNode*)NULL, node_);
 }
 
@@ -163,17 +174,34 @@ void MountHtml5FsNodeTest::InitNode() {
 // creation of the mount blocks until the filesystem is ready.
 class MountHtml5FsNodeSyncTest : public MountHtml5FsNodeTest {
  public:
+  void SetUpForFileType(PP_FileType file_type);
+
   virtual void SetUp();
 };
 
-void MountHtml5FsNodeSyncTest::SetUp() {
+void MountHtml5FsNodeSyncTest::SetUpForFileType(PP_FileType file_type) {
   MountHtml5FsNodeTest::SetUp();
   SetUpFilesystemExpectations(PP_FILESYSTEMTYPE_LOCALPERSISTENT, 0);
   InitFilesystem();
-  SetUpNodeExpectations();
+  SetUpNodeExpectations(file_type);
   InitNode();
 }
 
+void MountHtml5FsNodeSyncTest::SetUp() {
+  SetUpForFileType(PP_FILETYPE_REGULAR);
+}
+
+// Node test where the filesystem is opened synchronously, and the node is a
+// directory.
+class MountHtml5FsNodeSyncDirTest : public MountHtml5FsNodeSyncTest {
+ public:
+  virtual void SetUp();
+};
+
+void MountHtml5FsNodeSyncDirTest::SetUp() {
+  SetUpForFileType(PP_FILETYPE_DIRECTORY);
+}
+
 void ReadDirectoryEntriesAction(const PP_ArrayOutput& output) {
   const int fileref_resource_1 = 238;
   const int fileref_resource_2 = 239;
@@ -224,7 +252,7 @@ void MountHtml5FsNodeAsyncTest::SetUp() {
   // true => asynchronous filesystem open.
   SetUpFilesystemExpectations(PP_FILESYSTEMTYPE_LOCALPERSISTENT, 0, true);
   InitFilesystem();
-  SetUpNodeExpectations();
+  SetUpNodeExpectations(PP_FILETYPE_REGULAR);
 
   // Signal the other thread to try opening a Node.
   pthread_mutex_lock(&mutex_);
@@ -350,7 +378,8 @@ TEST_F(MountHtml5FsNodeSyncTest, Write) {
   EXPECT_CALL(*fileio_, Write(fileio_resource_, offset, &buffer[0], count, _))
       .WillOnce(Return(count));
 
-  int result = node_->Write(offset, &buffer, count);
+  int result = 0;
+  EXPECT_EQ(0, node_->Write(offset, &buffer, count, &result));
   EXPECT_EQ(count, result);
 }
 
@@ -362,7 +391,8 @@ TEST_F(MountHtml5FsNodeSyncTest, Read) {
   EXPECT_CALL(*fileio_, Read(fileio_resource_, offset, &buffer[0], count, _))
       .WillOnce(Return(count));
 
-  int result = node_->Read(offset, &buffer, count);
+  int result = 0;
+  EXPECT_EQ(0, node_->Read(offset, &buffer, count, &result));
   EXPECT_EQ(count, result);
 }
 
@@ -380,7 +410,7 @@ TEST_F(MountHtml5FsNodeSyncTest, GetStat) {
   info.last_access_time = access_time;
   info.last_modified_time = modified_time;
 
-  EXPECT_CALL(*fileio_, Query(fileio_resource_, _, _))
+  EXPECT_CALL(*fileref_, Query(fileref_resource_, _, _))
       .WillOnce(DoAll(SetArgPointee<1>(info),
                       Return(int32_t(PP_OK))));
 
@@ -405,6 +435,76 @@ TEST_F(MountHtml5FsNodeSyncTest, FTruncate) {
 }
 
 TEST_F(MountHtml5FsNodeSyncTest, GetDents) {
+  struct dirent dirents[2];
+  memset(&dirents[0], 0, sizeof(dirents));
+
+  // Should fail for regular files.
+  int result_bytes = 0;
+  EXPECT_EQ(ENOTDIR, node_->GetDents(0, &dirents[0], sizeof(dirent) * 2,
+        &result_bytes));
+  ASSERT_EQ(0, result_bytes);
+}
+
+TEST_F(MountHtml5FsNodeSyncDirTest, OpenAndClose) {
+}
+
+TEST_F(MountHtml5FsNodeSyncDirTest, Write) {
+  const int offset = 10;
+  const int count = 20;
+  const char buffer[30] = {0};
+
+  // Should fail for directories.
+  int result_bytes = 0;
+  EXPECT_EQ(EISDIR, node_->Write(offset, &buffer, count, &result_bytes));
+  ASSERT_EQ(0, result_bytes);
+}
+
+TEST_F(MountHtml5FsNodeSyncDirTest, Read) {
+  const int offset = 10;
+  const int count = 20;
+  char buffer[30] = {0};
+
+  // Should fail for directories.
+  int result_bytes = 0;
+  EXPECT_EQ(EISDIR, node_->Read(offset, &buffer, count, &result_bytes));
+  ASSERT_EQ(0, result_bytes);
+}
+
+TEST_F(MountHtml5FsNodeSyncDirTest, GetStat) {
+  const int creation_time = 1000;
+  const int access_time = 2000;
+  const int modified_time = 3000;
+
+  PP_FileInfo info;
+  info.size = 0;
+  info.type = PP_FILETYPE_DIRECTORY;
+  info.system_type = PP_FILESYSTEMTYPE_LOCALPERSISTENT;
+  info.creation_time = creation_time;
+  info.last_access_time = access_time;
+  info.last_modified_time = modified_time;
+
+  EXPECT_CALL(*fileref_, Query(fileref_resource_, _, _))
+      .WillOnce(DoAll(SetArgPointee<1>(info),
+                      Return(int32_t(PP_OK))));
+
+  struct stat statbuf;
+  int result = node_->GetStat(&statbuf);
+
+  EXPECT_EQ(0, result);
+  EXPECT_EQ(S_IFDIR | S_IWRITE | S_IREAD, statbuf.st_mode);
+  EXPECT_EQ(0, statbuf.st_size);
+  EXPECT_EQ(access_time, statbuf.st_atime);
+  EXPECT_EQ(modified_time, statbuf.st_mtime);
+  EXPECT_EQ(creation_time, statbuf.st_ctime);
+}
+
+TEST_F(MountHtml5FsNodeSyncDirTest, FTruncate) {
+  const int size = 123;
+  // Should fail for directories.
+  EXPECT_EQ(EISDIR, node_->FTruncate(size));
+}
+
+TEST_F(MountHtml5FsNodeSyncDirTest, GetDents) {
   const int fileref_resource_1 = 238;
   const int fileref_resource_2 = 239;
 
@@ -441,9 +541,20 @@ TEST_F(MountHtml5FsNodeSyncTest, GetDents) {
 
   struct dirent dirents[2];
   memset(&dirents[0], 0, sizeof(dirents));
-  int result = node_->GetDents(0, &dirents[0], sizeof(dirent) * 2);
-
-  EXPECT_EQ(0, result);
-  EXPECT_STREQ(&fileref_name_cstr_1[0], &dirents[0].d_name[0]);
-  EXPECT_STREQ(&fileref_name_cstr_2[0], &dirents[1].d_name[0]);
+  // +2 to test a size that is not a multiple of sizeof(dirent).
+  // Expect it to round down.
+  int result_bytes = 0;
+  EXPECT_EQ(
+      0,
+      node_->GetDents(0, &dirents[0], sizeof(dirent) * 2 + 2, &result_bytes));
+
+  ASSERT_EQ(sizeof(dirent) * 2, result_bytes);
+  EXPECT_LT(0, dirents[0].d_ino);  // 0 is an invalid inode number.
+  EXPECT_EQ(sizeof(dirent), dirents[0].d_off);
+  EXPECT_EQ(sizeof(dirent), dirents[0].d_reclen);
+  EXPECT_STREQ(fileref_name_cstr_1, dirents[0].d_name);
+  EXPECT_LT(0, dirents[1].d_ino);  // 0 is an invalid inode number.
+  EXPECT_EQ(sizeof(dirent), dirents[1].d_off);
+  EXPECT_EQ(sizeof(dirent), dirents[1].d_reclen);
+  EXPECT_STREQ(fileref_name_cstr_2, dirents[1].d_name);
 }
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_http_test.cc b/native_client_sdk/src/libraries/nacl_io_test/mount_http_test.cc
index 350874d34d..ced8d06a6c 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/mount_http_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_http_test.cc
@@ -29,7 +29,7 @@ using ::testing::StrEq;
 class MountHttpMock : public MountHttp {
  public:
   MountHttpMock(StringMap_t map, PepperInterfaceMock* ppapi) {
-    EXPECT_TRUE(Init(1, map, ppapi));
+    EXPECT_EQ(0, Init(1, map, ppapi));
   }
 
   ~MountHttpMock() {
@@ -71,25 +71,34 @@ TEST_F(MountHttpTest, MountEmpty) {
 
 TEST_F(MountHttpTest, ParseManifest) {
   StringMap_t args;
+  size_t result_size = 0;
+
   mnt_ = new MountHttpMock(args, &ppapi_);
 
   char manifest[] = "-r-- 123 /mydir/foo\n-rw- 234 /thatdir/bar\n";
-  EXPECT_TRUE(mnt_->ParseManifest(manifest));
+  EXPECT_EQ(0, mnt_->ParseManifest(manifest));
 
-  MountNodeDir* root = mnt_->FindOrCreateDir(Path("/"));
+  MountNodeDir* root = NULL;
+  EXPECT_EQ(0, mnt_->FindOrCreateDir(Path("/"), &root));
+  ASSERT_NE((MountNode*)NULL, root);
   EXPECT_EQ(2, root->ChildCount());
 
-  MountNodeDir* dir = mnt_->FindOrCreateDir(Path("/mydir"));
+  MountNodeDir* dir = NULL;
+  EXPECT_EQ(0, mnt_->FindOrCreateDir(Path("/mydir"), &dir));
+  ASSERT_NE((MountNode*)NULL, dir);
   EXPECT_EQ(1, dir->ChildCount());
 
   MountNode* node = mnt_->GetMap()["/mydir/foo"];
-  EXPECT_TRUE(node);
-  EXPECT_EQ(123, node->GetSize());
+  EXPECT_NE((MountNode*)NULL, node);
+  EXPECT_EQ(0, node->GetSize(&result_size));
+  EXPECT_EQ(123, result_size);
 
   // Since these files are cached thanks to the manifest, we can open them
   // without accessing the PPAPI URL API.
-  MountNode* foo = mnt_->Open(Path("/mydir/foo"), O_RDONLY);
-  MountNode* bar = mnt_->Open(Path("/thatdir/bar"), O_RDWR);
+  MountNode* foo = NULL;
+  EXPECT_EQ(0, mnt_->Open(Path("/mydir/foo"), O_RDONLY, &foo));
+  MountNode* bar = NULL;
+  EXPECT_EQ(0, mnt_->Open(Path("/thatdir/bar"), O_RDWR, &bar));
 
   struct stat sfoo;
   struct stat sbar;
@@ -248,7 +257,7 @@ void MountHttpNodeTest::SetResponseBody(const char* body) {
 }
 
 void MountHttpNodeTest::OpenNode() {
-  node_ = mnt_->Open(Path(path_), O_RDONLY);
+  ASSERT_EQ(0, mnt_->Open(Path(path_), O_RDONLY, &node_));
   ASSERT_NE((MountNode*)NULL, node_);
 }
 
@@ -266,7 +275,9 @@ void MountHttpNodeTest::TearDown() {
   delete mnt_;
 }
 
-TEST_F(MountHttpNodeTest, OpenAndClose) {
+TEST_F(MountHttpNodeTest, OpenAndCloseNoCache) {
+  StringMap_t smap;
+  smap["cache_content"] = "false";
   SetMountArgs(StringMap_t());
   ExpectOpen("HEAD");
   ExpectHeaders("");
@@ -275,6 +286,9 @@ TEST_F(MountHttpNodeTest, OpenAndClose) {
 }
 
 TEST_F(MountHttpNodeTest, ReadCached) {
+  size_t result_size = 0;
+  int result_bytes = 0;
+
   SetMountArgs(StringMap_t());
   ExpectOpen("HEAD");
   ExpectHeaders("");
@@ -282,7 +296,8 @@ TEST_F(MountHttpNodeTest, ReadCached) {
   OpenNode();
   ResetMocks();
 
-  EXPECT_EQ(42, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(42, result_size);
 
   char buf[10];
   memset(&buf[0], 0, sizeof(buf));
@@ -291,20 +306,24 @@ TEST_F(MountHttpNodeTest, ReadCached) {
   ExpectHeaders("");
   SetResponse(200, "Content-Length: 42\n");
   SetResponseBody("Here is some response text. And some more.");
-  node_->Read(0, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(0, buf, sizeof(buf) - 1, &result_bytes));
   EXPECT_STREQ("Here is s", &buf[0]);
   ResetMocks();
 
   // Further reads should be cached.
-  node_->Read(0, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(0, buf, sizeof(buf) - 1, &result_bytes));
   EXPECT_STREQ("Here is s", &buf[0]);
-  node_->Read(10, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(10, buf, sizeof(buf) - 1, &result_bytes));
   EXPECT_STREQ("me respon", &buf[0]);
 
-  EXPECT_EQ(42, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(42, result_size);
 }
 
 TEST_F(MountHttpNodeTest, ReadCachedNoContentLength) {
+  size_t result_size = 0;
+  int result_bytes = 0;
+
   SetMountArgs(StringMap_t());
   ExpectOpen("HEAD");
   ExpectHeaders("");
@@ -319,25 +338,30 @@ TEST_F(MountHttpNodeTest, ReadCachedNoContentLength) {
 
   // GetSize will Read() because it didn't get the content length from the HEAD
   // request.
-  EXPECT_EQ(42, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(42, result_size);
 
   char buf[10];
   memset(&buf[0], 0, sizeof(buf));
 
-  node_->Read(0, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(0, buf, sizeof(buf) - 1, &result_bytes));
   EXPECT_STREQ("Here is s", &buf[0]);
   ResetMocks();
 
   // Further reads should be cached.
-  node_->Read(0, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(0, buf, sizeof(buf) - 1, &result_bytes));
   EXPECT_STREQ("Here is s", &buf[0]);
-  node_->Read(10, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(10, buf, sizeof(buf) - 1, &result_bytes));
   EXPECT_STREQ("me respon", &buf[0]);
 
-  EXPECT_EQ(42, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(42, result_size);
 }
 
 TEST_F(MountHttpNodeTest, ReadCachedUnderrun) {
+  size_t result_size = 0;
+  int result_bytes = 0;
+
   SetMountArgs(StringMap_t());
   ExpectOpen("HEAD");
   ExpectHeaders("");
@@ -345,7 +369,8 @@ TEST_F(MountHttpNodeTest, ReadCachedUnderrun) {
   OpenNode();
   ResetMocks();
 
-  EXPECT_EQ(100, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(100, result_size);
 
   char buf[10];
   memset(&buf[0], 0, sizeof(buf));
@@ -354,14 +379,19 @@ TEST_F(MountHttpNodeTest, ReadCachedUnderrun) {
   ExpectHeaders("");
   SetResponse(200, "Content-Length: 100\n");
   SetResponseBody("abcdefghijklmnopqrstuvwxyz");
-  node_->Read(0, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(0, buf, sizeof(buf) - 1, &result_bytes));
+  EXPECT_EQ(sizeof(buf) - 1, result_bytes);
   EXPECT_STREQ("abcdefghi", &buf[0]);
   ResetMocks();
 
-  EXPECT_EQ(26, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(26, result_size);
 }
 
 TEST_F(MountHttpNodeTest, ReadCachedOverrun) {
+  size_t result_size = 0;
+  int result_bytes = 0;
+
   SetMountArgs(StringMap_t());
   ExpectOpen("HEAD");
   ExpectHeaders("");
@@ -369,7 +399,8 @@ TEST_F(MountHttpNodeTest, ReadCachedOverrun) {
   OpenNode();
   ResetMocks();
 
-  EXPECT_EQ(15, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(15, result_size);
 
   char buf[10];
   memset(&buf[0], 0, sizeof(buf));
@@ -378,14 +409,18 @@ TEST_F(MountHttpNodeTest, ReadCachedOverrun) {
   ExpectHeaders("");
   SetResponse(200, "Content-Length: 15\n");
   SetResponseBody("01234567890123456789");
-  node_->Read(10, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(10, buf, sizeof(buf) - 1, &result_bytes));
+  EXPECT_EQ(5, result_bytes);
   EXPECT_STREQ("01234", &buf[0]);
   ResetMocks();
 
-  EXPECT_EQ(15, node_->GetSize());
+  EXPECT_EQ(0, node_->GetSize(&result_size));
+  EXPECT_EQ(15, result_size);
 }
 
 TEST_F(MountHttpNodeTest, ReadPartial) {
+  int result_bytes = 0;
+
   StringMap_t args;
   args["cache_content"] = "false";
   SetMountArgs(args);
@@ -402,7 +437,8 @@ TEST_F(MountHttpNodeTest, ReadPartial) {
   ExpectHeaders("Range: bytes=0-8\n");
   SetResponse(206, "Content-Length: 9\nContent-Range: bytes=0-8\n");
   SetResponseBody("012345678");
-  node_->Read(0, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(0, buf, sizeof(buf) - 1, &result_bytes));
+  EXPECT_EQ(sizeof(buf) - 1, result_bytes);
   EXPECT_STREQ("012345678", &buf[0]);
   ResetMocks();
 
@@ -411,11 +447,14 @@ TEST_F(MountHttpNodeTest, ReadPartial) {
   ExpectHeaders("Range: bytes=10-18\n");
   SetResponse(206, "Content-Length: 9\nContent-Range: bytes=10-18\n");
   SetResponseBody("abcdefghi");
-  node_->Read(10, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(10, buf, sizeof(buf) - 1, &result_bytes));
+  EXPECT_EQ(sizeof(buf) - 1, result_bytes);
   EXPECT_STREQ("abcdefghi", &buf[0]);
 }
 
 TEST_F(MountHttpNodeTest, ReadPartialNoServerSupport) {
+  int result_bytes = 0;
+
   StringMap_t args;
   args["cache_content"] = "false";
   SetMountArgs(args);
@@ -432,6 +471,7 @@ TEST_F(MountHttpNodeTest, ReadPartialNoServerSupport) {
   ExpectHeaders("Range: bytes=10-18\n");
   SetResponse(200, "Content-Length: 20\n");
   SetResponseBody("0123456789abcdefghij");
-  node_->Read(10, buf, sizeof(buf) - 1);
+  EXPECT_EQ(0, node_->Read(10, buf, sizeof(buf) - 1, &result_bytes));
+  EXPECT_EQ(sizeof(buf) - 1, result_bytes);
   EXPECT_STREQ("abcdefghi", &buf[0]);
 }
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_node_test.cc b/native_client_sdk/src/libraries/nacl_io_test/mount_node_test.cc
index 2de13cd468..bc6fa65ed6 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/mount_node_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_node_test.cc
@@ -6,6 +6,7 @@
 #include <errno.h>
 #include <fcntl.h>
 
+#include "nacl_io/error.h"
 #include "nacl_io/kernel_proxy.h"
 #include "nacl_io/mount_node.h"
 #include "nacl_io/mount_node_dir.h"
@@ -14,31 +15,25 @@
 
 #include "gtest/gtest.h"
 
-#define NULL_NODE ((MountNode *) NULL)
+#define NULL_NODE ((MountNode*) NULL)
 
 static int s_AllocNum = 0;
 
 class MockMemory : public MountNodeMem {
  public:
-  MockMemory() : MountNodeMem(NULL) {
-    s_AllocNum++;
-  }
+  MockMemory() : MountNodeMem(NULL) { s_AllocNum++; }
 
-  ~MockMemory() {
-    s_AllocNum--;
-  }
+  ~MockMemory() { s_AllocNum--; }
 
-  bool Init(int mode) {
-    return MountNodeMem::Init(mode);
-  }
-  int AddChild(const std::string& name, MountNode *node) {
+  Error Init(int mode) { return MountNodeMem::Init(mode); }
+  Error AddChild(const std::string& name, MountNode* node) {
     return MountNodeMem::AddChild(name, node);
   }
-  int RemoveChild(const std::string& name) {
+  Error RemoveChild(const std::string& name) {
     return MountNodeMem::RemoveChild(name);
   }
-  MountNode* FindChild(const std::string& name) {
-    return MountNodeMem::FindChild(name);
+  Error FindChild(const std::string& name, MountNode** out_node) {
+    return MountNodeMem::FindChild(name, out_node);
   }
   void Link() { MountNodeMem::Link(); }
   void Unlink() { MountNodeMem::Unlink(); }
@@ -49,25 +44,19 @@ class MockMemory : public MountNodeMem {
 
 class MockDir : public MountNodeDir {
  public:
-  MockDir() : MountNodeDir(NULL) {
-    s_AllocNum++;
-  }
+  MockDir() : MountNodeDir(NULL) { s_AllocNum++; }
 
-  ~MockDir() {
-    s_AllocNum--;
-  }
+  ~MockDir() { s_AllocNum--; }
 
-  bool Init(int mode) {
-    return MountNodeDir::Init(mode);
-  }
-  int AddChild(const std::string& name, MountNode *node) {
+  Error Init(int mode) { return MountNodeDir::Init(mode); }
+  Error AddChild(const std::string& name, MountNode* node) {
     return MountNodeDir::AddChild(name, node);
   }
-  int RemoveChild(const std::string& name) {
+  Error RemoveChild(const std::string& name) {
     return MountNodeDir::RemoveChild(name);
   }
-  MountNode* FindChild(const std::string& name) {
-    return MountNodeDir::FindChild(name);
+  Error FindChild(const std::string& name, MountNode** out_node) {
+    return MountNodeDir::FindChild(name, out_node);
   }
   void Link() { MountNodeDir::Link(); }
   void Unlink() { MountNodeDir::Unlink(); }
@@ -77,9 +66,12 @@ class MockDir : public MountNodeDir {
 };
 
 TEST(MountNodeTest, File) {
-  MockMemory *file = new MockMemory;
+  MockMemory* file = new MockMemory;
+  MountNode* result_node = NULL;
+  size_t result_size = 0;
+  int result_bytes = 0;
 
-  EXPECT_TRUE(file->Init(S_IREAD | S_IWRITE));
+  EXPECT_EQ(0, file->Init(S_IREAD | S_IWRITE));
 
   // Test properties
   EXPECT_EQ(0, file->GetLinks());
@@ -97,12 +89,18 @@ TEST(MountNodeTest, File) {
     buf1[a] = a;
   memset(buf2, 0, sizeof(buf2));
 
-  EXPECT_EQ(0, file->GetSize());
-  EXPECT_EQ(0, file->Read(0, buf2, sizeof(buf2)));
-  EXPECT_EQ(0, file->GetSize());
-  EXPECT_EQ(sizeof(buf1), file->Write(0, buf1, sizeof(buf1)));
-  EXPECT_EQ(sizeof(buf1), file->GetSize());
-  EXPECT_EQ(sizeof(buf1), file->Read(0, buf2, sizeof(buf2)));
+  EXPECT_EQ(0, file->GetSize(&result_size));
+  EXPECT_EQ(0, result_size);
+  EXPECT_EQ(0, file->Read(0, buf2, sizeof(buf2), &result_bytes));
+  EXPECT_EQ(0, result_bytes);
+  EXPECT_EQ(0, file->GetSize(&result_size));
+  EXPECT_EQ(0, result_size);
+  EXPECT_EQ(0, file->Write(0, buf1, sizeof(buf1), &result_bytes));
+  EXPECT_EQ(sizeof(buf1), result_bytes);
+  EXPECT_EQ(0, file->GetSize(&result_size));
+  EXPECT_EQ(sizeof(buf1), result_size);
+  EXPECT_EQ(0, file->Read(0, buf2, sizeof(buf2), &result_bytes));
+  EXPECT_EQ(sizeof(buf1), result_bytes);
   EXPECT_EQ(0, memcmp(buf1, buf2, sizeof(buf1)));
 
   struct stat s;
@@ -112,20 +110,21 @@ TEST(MountNodeTest, File) {
 
   // Directory operations should fail
   struct dirent d;
-  EXPECT_EQ(-1, file->GetDents(0, &d, sizeof(d)));
-  EXPECT_EQ(errno, ENOTDIR);
-  EXPECT_EQ(-1, file->AddChild("", file));
-  EXPECT_EQ(errno, ENOTDIR);
-  EXPECT_EQ(-1, file->RemoveChild(""));
-  EXPECT_EQ(errno, ENOTDIR);
-  EXPECT_EQ(NULL_NODE, file->FindChild(""));
-  EXPECT_EQ(errno, ENOTDIR);
+  EXPECT_EQ(ENOTDIR, file->GetDents(0, &d, sizeof(d), &result_bytes));
+  EXPECT_EQ(ENOTDIR, file->AddChild("", file));
+  EXPECT_EQ(ENOTDIR, file->RemoveChild(""));
+  EXPECT_EQ(ENOTDIR, file->FindChild("", &result_node));
+  EXPECT_EQ(NULL_NODE, result_node);
 
   delete file;
 }
 
 TEST(MountNodeTest, Directory) {
-  MockDir *root = new MockDir();
+  MockDir* root = new MockDir();
+  MountNode* result_node = NULL;
+  size_t result_size = 0;
+  int result_bytes = 0;
+
   root->Init(S_IREAD | S_IWRITE);
 
   // Test properties
@@ -139,15 +138,14 @@ TEST(MountNodeTest, Directory) {
 
   // IO operations should fail
   char buf1[1024];
-  EXPECT_EQ(0, root->GetSize());
-  EXPECT_EQ(-1, root->Read(0, buf1, sizeof(buf1)));
-  EXPECT_EQ(errno, EISDIR);
-  EXPECT_EQ(-1, root->Write(0, buf1, sizeof(buf1)));
-  EXPECT_EQ(errno, EISDIR);
+  EXPECT_EQ(0, root->GetSize(&result_size));
+  EXPECT_EQ(0, result_size);
+  EXPECT_EQ(EISDIR, root->Read(0, buf1, sizeof(buf1), &result_bytes));
+  EXPECT_EQ(EISDIR, root->Write(0, buf1, sizeof(buf1), &result_bytes));
 
   // Test directory operations
   MockMemory* file = new MockMemory;
-  EXPECT_TRUE(file->Init(S_IREAD | S_IWRITE));
+  EXPECT_EQ(0, file->Init(S_IREAD | S_IWRITE));
 
   EXPECT_EQ(1, root->RefCount());
   EXPECT_EQ(1, file->RefCount());
@@ -157,25 +155,28 @@ TEST(MountNodeTest, Directory) {
 
   // Test that the directory is there
   struct dirent d;
-  EXPECT_EQ(sizeof(d), root->GetDents(0, &d, sizeof(d)));
+  EXPECT_EQ(0, root->GetDents(0, &d, sizeof(d), &result_bytes));
+  EXPECT_EQ(sizeof(d), result_bytes);
   EXPECT_LT(0, d.d_ino);  // 0 is an invalid inode number.
   EXPECT_EQ(sizeof(d), d.d_off);
   EXPECT_EQ(sizeof(d), d.d_reclen);
   EXPECT_EQ(0, strcmp("F1", d.d_name));
-  EXPECT_EQ(0, root->GetDents(sizeof(d), &d, sizeof(d)));
+  EXPECT_EQ(0, root->GetDents(sizeof(d), &d, sizeof(d), &result_bytes));
+  EXPECT_EQ(0, result_bytes);
 
   EXPECT_EQ(0, root->AddChild("F2", file));
   EXPECT_EQ(2, file->GetLinks());
   EXPECT_EQ(3, file->RefCount());
-  EXPECT_EQ(-1, root->AddChild("F1", file));
-  EXPECT_EQ(EEXIST, errno);
+  EXPECT_EQ(EEXIST, root->AddChild("F1", file));
   EXPECT_EQ(2, file->GetLinks());
 
   EXPECT_EQ(2, s_AllocNum);
-  EXPECT_NE(NULL_NODE, root->FindChild("F1"));
-  EXPECT_NE(NULL_NODE, root->FindChild("F2"));
-  EXPECT_EQ(NULL_NODE, root->FindChild("F3"));
-  EXPECT_EQ(errno, ENOENT);
+  EXPECT_EQ(0, root->FindChild("F1", &result_node));
+  EXPECT_NE(NULL_NODE, result_node);
+  EXPECT_EQ(0, root->FindChild("F2", &result_node));
+  EXPECT_NE(NULL_NODE, result_node);
+  EXPECT_EQ(ENOENT, root->FindChild("F3", &result_node));
+  EXPECT_EQ(NULL_NODE, result_node);
 
   EXPECT_EQ(2, s_AllocNum);
   EXPECT_EQ(0, root->RemoveChild("F1"));
diff --git a/native_client_sdk/src/libraries/nacl_io_test/mount_test.cc b/native_client_sdk/src/libraries/nacl_io_test/mount_test.cc
index 1604ccafd3..245d13daf4 100644
--- a/native_client_sdk/src/libraries/nacl_io_test/mount_test.cc
+++ b/native_client_sdk/src/libraries/nacl_io_test/mount_test.cc
@@ -22,12 +22,10 @@ class MountMemMock : public MountMem {
  public:
   MountMemMock() {
     StringMap_t map;
-    Init(1, map, NULL);
-  };
-
-  int num_nodes() {
-    return (int) inode_pool_.size();
+    EXPECT_EQ(0, Init(1, map, NULL));
   }
+
+  int num_nodes() { return (int) inode_pool_.size(); }
 };
 
 class MountDevMock : public MountDev {
@@ -36,20 +34,20 @@ class MountDevMock : public MountDev {
     StringMap_t map;
     Init(1, map, NULL);
   }
-  int num_nodes() {
-    return (int) inode_pool_.size();
-  }
+  int num_nodes() { return (int) inode_pool_.size(); }
 };
 
 }  // namespace
 
-
-#define NULL_NODE ((MountNode *) NULL)
+#define NULL_NODE ((MountNode*) NULL)
 
 TEST(MountTest, Sanity) {
   MountMemMock* mnt = new MountMemMock();
   MountNode* file;
   MountNode* root;
+  MountNode* result_node;
+  size_t result_size = 0;
+  int result_bytes = 0;
 
   char buf1[1024];
 
@@ -57,43 +55,54 @@ TEST(MountTest, Sanity) {
   EXPECT_EQ(1, mnt->num_nodes());
 
   // Fail to open non existent file
-  EXPECT_EQ(NULL_NODE, mnt->Open(Path("/foo"), O_RDWR));
-  EXPECT_EQ(errno, ENOENT);
+  EXPECT_EQ(ENOENT, mnt->Open(Path("/foo"), O_RDWR, &result_node));
+  EXPECT_EQ(NULL, result_node);
 
   // Create a file
-  file =  mnt->Open(Path("/foo"), O_RDWR | O_CREAT);
+  EXPECT_EQ(0, mnt->Open(Path("/foo"), O_RDWR | O_CREAT, &file));
   EXPECT_NE(NULL_NODE, file);
-  if (file == NULL) return;
+  if (file == NULL)
+    return;
   EXPECT_EQ(2, file->RefCount());
   EXPECT_EQ(2, mnt->num_nodes());
 
+  // Open the root directory for write should fail.
+  EXPECT_EQ(EISDIR, mnt->Open(Path("/"), O_RDWR, &root));
+
   // Open the root directory
-  root = mnt->Open(Path("/"), O_RDWR);
+  EXPECT_EQ(0, mnt->Open(Path("/"), O_RDONLY, &root));
   EXPECT_NE(NULL_NODE, root);
   if (NULL != root) {
     struct dirent dirs[2];
-    int len = root->GetDents(0, dirs, sizeof(dirs));
+    int len;
+    EXPECT_EQ(0, root->GetDents(0, dirs, sizeof(dirs), &len));
     EXPECT_EQ(sizeof(struct dirent), len);
   }
 
   // Fail to re-create the same file
-  EXPECT_EQ(NULL_NODE, mnt->Open(Path("/foo"), O_RDWR | O_CREAT | O_EXCL));
-  EXPECT_EQ(errno, EEXIST);
+  EXPECT_EQ(EEXIST,
+            mnt->Open(Path("/foo"), O_RDWR | O_CREAT | O_EXCL, &result_node));
+  EXPECT_EQ(NULL_NODE, result_node);
   EXPECT_EQ(2, mnt->num_nodes());
 
   // Fail to create a directory with the same name
-  EXPECT_EQ(-1, mnt->Mkdir(Path("/foo"), O_RDWR));
-  EXPECT_EQ(errno, EEXIST);
+  EXPECT_EQ(EEXIST, mnt->Mkdir(Path("/foo"), O_RDWR));
 
   // Attempt to READ/WRITE
-  EXPECT_EQ(0, file->GetSize());
-  EXPECT_EQ(sizeof(buf1), file->Write(0, buf1, sizeof(buf1)));
-  EXPECT_EQ(sizeof(buf1), file->GetSize());
-  EXPECT_EQ(sizeof(buf1), file->Read(0, buf1, sizeof(buf1)));
+  EXPECT_EQ(0, file->GetSize(&result_size));
+  EXPECT_EQ(0, result_size);
+  EXPECT_EQ(0, file->Write(0, buf1, sizeof(buf1), &result_bytes));
+  EXPECT_EQ(sizeof(buf1), result_bytes);
+  EXPECT_EQ(0, file->GetSize(&result_size));
+  EXPECT_EQ(sizeof(buf1), result_size);
+  EXPECT_EQ(0, file->Read(0, buf1, sizeof(buf1), &result_bytes));
+  EXPECT_EQ(sizeof(buf1), result_bytes);
 
   // Attempt to open the same file
-  EXPECT_EQ(file, mnt->Open(Path("/foo"), O_RDWR | O_CREAT));
-  EXPECT_EQ(sizeof(buf1), file->GetSize());
+  EXPECT_EQ(0, mnt->Open(Path("/foo"), O_RDWR | O_CREAT, &result_node));
+  EXPECT_EQ(file, result_node);
+  EXPECT_EQ(0, file->GetSize(&result_size));
+  EXPECT_EQ(sizeof(buf1), result_size);
   EXPECT_EQ(3, file->RefCount());
   EXPECT_EQ(2, mnt->num_nodes());
 
@@ -102,9 +111,8 @@ TEST(MountTest, Sanity) {
   EXPECT_EQ(2, mnt->num_nodes());
   EXPECT_EQ(0, mnt->Unlink(Path("/foo")));
   EXPECT_EQ(2, mnt->num_nodes());
-  EXPECT_EQ(-1, mnt->Unlink(Path("/foo")));
+  EXPECT_EQ(ENOENT, mnt->Unlink(Path("/foo")));
   EXPECT_EQ(2, mnt->num_nodes());
-  EXPECT_EQ(errno, ENOENT);
   mnt->ReleaseNode(file);
   EXPECT_EQ(1, mnt->num_nodes());
 
@@ -112,13 +120,13 @@ TEST(MountTest, Sanity) {
   EXPECT_EQ(0, mnt->Mkdir(Path("/foo"), O_RDWR));
 
   // Create a file (exclusively)
-  file =  mnt->Open(Path("/foo/bar"), O_RDWR | O_CREAT | O_EXCL);
+  EXPECT_EQ(0, mnt->Open(Path("/foo/bar"), O_RDWR | O_CREAT | O_EXCL, &file));
   EXPECT_NE(NULL_NODE, file);
-  if (NULL == file) return;
+  if (NULL == file)
+    return;
 
   // Attempt to delete the directory
-  EXPECT_EQ(-1, mnt->Rmdir(Path("/foo")));
-  EXPECT_EQ(errno, ENOTEMPTY);
+  EXPECT_EQ(ENOTEMPTY, mnt->Rmdir(Path("/foo")));
 
   // Unlink the file, then delete the directory
   EXPECT_EQ(0, mnt->Unlink(Path("/foo/bar")));
@@ -128,60 +136,71 @@ TEST(MountTest, Sanity) {
   EXPECT_EQ(1, mnt->num_nodes());
 
   // Verify the directory is gone
-  file =  mnt->Open(Path("/foo"), O_RDWR);
+  EXPECT_EQ(ENOENT, mnt->Open(Path("/foo"), O_RDWR, &file));
   EXPECT_EQ(NULL_NODE, file);
-  EXPECT_EQ(errno, ENOENT);
 }
 
 TEST(MountTest, MemMountRemove) {
   MountMemMock* mnt = new MountMemMock();
   MountNode* file;
+  MountNode* result_node;
 
   EXPECT_EQ(0, mnt->Mkdir(Path("/dir"), O_RDWR));
-  file = mnt->Open(Path("/file"), O_RDWR | O_CREAT | O_EXCL);
+  EXPECT_EQ(0, mnt->Open(Path("/file"), O_RDWR | O_CREAT | O_EXCL, &file));
   EXPECT_NE(NULL_NODE, file);
   mnt->ReleaseNode(file);
 
   EXPECT_EQ(0, mnt->Remove(Path("/dir")));
   EXPECT_EQ(0, mnt->Remove(Path("/file")));
 
-  EXPECT_EQ(NULL_NODE, mnt->Open(Path("/dir/foo"), O_CREAT | O_RDWR));
-  EXPECT_EQ(ENOENT, errno);
-  EXPECT_EQ(NULL_NODE, mnt->Open(Path("/file"), O_RDONLY));
-  EXPECT_EQ(ENOENT, errno);
+  EXPECT_EQ(ENOENT,
+            mnt->Open(Path("/dir/foo"), O_CREAT | O_RDWR, &result_node));
+  EXPECT_EQ(NULL_NODE, result_node);
+  EXPECT_EQ(ENOENT, mnt->Open(Path("/file"), O_RDONLY, &result_node));
+  EXPECT_EQ(NULL_NODE, result_node);
 }
 
 TEST(MountTest, DevNull) {
   MountDevMock* mnt = new MountDevMock();
-  MountNode* dev_null = mnt->Open(Path("/null"), O_RDWR);
+  MountNode* dev_null = NULL;
+  int result_bytes = 0;
+
+  ASSERT_EQ(0, mnt->Open(Path("/null"), O_RDWR, &dev_null));
   ASSERT_NE(NULL_NODE, dev_null);
 
   // Writing to /dev/null should write everything.
   const char msg[] = "Dummy test message.";
-  EXPECT_EQ(strlen(msg), dev_null->Write(0, &msg[0], strlen(msg)));
+  EXPECT_EQ(0, dev_null->Write(0, &msg[0], strlen(msg), &result_bytes));
+  EXPECT_EQ(strlen(msg), result_bytes);
 
   // Reading from /dev/null should read nothing.
   const int kBufferLength = 100;
   char buffer[kBufferLength];
-  EXPECT_EQ(0, dev_null->Read(0, &buffer[0], kBufferLength));
+  EXPECT_EQ(0, dev_null->Read(0, &buffer[0], kBufferLength, &result_bytes));
+  EXPECT_EQ(0, result_bytes);
   mnt->ReleaseNode(dev_null);
 }
 
 TEST(MountTest, DevZero) {
   MountDevMock* mnt = new MountDevMock();
-  MountNode* dev_zero = mnt->Open(Path("/zero"), O_RDWR);
+  MountNode* dev_zero = NULL;
+  int result_bytes = 0;
+
+  ASSERT_EQ(0, mnt->Open(Path("/zero"), O_RDWR, &dev_zero));
   ASSERT_NE(NULL_NODE, dev_zero);
 
   // Writing to /dev/zero should write everything.
   const char msg[] = "Dummy test message.";
-  EXPECT_EQ(strlen(msg), dev_zero->Write(0, &msg[0], strlen(msg)));
+  EXPECT_EQ(0, dev_zero->Write(0, &msg[0], strlen(msg), &result_bytes));
+  EXPECT_EQ(strlen(msg), result_bytes);
 
   // Reading from /dev/zero should read all zeroes.
   const int kBufferLength = 100;
   char buffer[kBufferLength];
   // First fill with all 1s.
   memset(&buffer[0], 0x1, kBufferLength);
-  EXPECT_EQ(kBufferLength, dev_zero->Read(0, &buffer[0], kBufferLength));
+  EXPECT_EQ(0, dev_zero->Read(0, &buffer[0], kBufferLength, &result_bytes));
+  EXPECT_EQ(kBufferLength, result_bytes);
 
   char zero_buffer[kBufferLength];
   memset(&zero_buffer[0], 0, kBufferLength);
@@ -191,12 +210,16 @@ TEST(MountTest, DevZero) {
 
 TEST(MountTest, DevUrandom) {
   MountDevMock* mnt = new MountDevMock();
-  MountNode* dev_urandom = mnt->Open(Path("/urandom"), O_RDWR);
+  MountNode* dev_urandom = NULL;
+  int result_bytes = 0;
+
+  ASSERT_EQ(0, mnt->Open(Path("/urandom"), O_RDWR, &dev_urandom));
   ASSERT_NE(NULL_NODE, dev_urandom);
 
-  // Writing to /dev/zero should write everything.
+  // Writing to /dev/urandom should write everything.
   const char msg[] = "Dummy test message.";
-  EXPECT_EQ(strlen(msg), dev_urandom->Write(0, &msg[0], strlen(msg)));
+  EXPECT_EQ(0, dev_urandom->Write(0, &msg[0], strlen(msg), &result_bytes));
+  EXPECT_EQ(strlen(msg), result_bytes);
 
   // Reading from /dev/urandom should read random bytes.
   const int kSampleBatches = 1000;
@@ -207,7 +230,9 @@ TEST(MountTest, DevUrandom) {
 
   unsigned char buffer[kSampleBatchSize];
   for (int batch = 0; batch < kSampleBatches; ++batch) {
-    int bytes_read = dev_urandom->Read(0, &buffer[0], kSampleBatchSize);
+    int bytes_read = 0;
+    EXPECT_EQ(0,
+              dev_urandom->Read(0, &buffer[0], kSampleBatchSize, &bytes_read));
     EXPECT_EQ(kSampleBatchSize, bytes_read);
 
     for (int i = 0; i < bytes_read; ++i) {
diff --git a/native_client_sdk/src/libraries/ppapi_cpp/library.dsc b/native_client_sdk/src/libraries/ppapi_cpp/library.dsc
index 2914c92a59..e6ffb6c26c 100644
--- a/native_client_sdk/src/libraries/ppapi_cpp/library.dsc
+++ b/native_client_sdk/src/libraries/ppapi_cpp/library.dsc
@@ -18,6 +18,7 @@
           'audio.cc',
           'audio_config.cc',
           'core.cc',
+          'directory_entry.cc',
           'file_io.cc',
           'file_ref.cc',
           'file_system.cc',
diff --git a/native_client_sdk/src/libraries/ppapi_cpp_private/library.dsc b/native_client_sdk/src/libraries/ppapi_cpp_private/library.dsc
index 50b9201a4d..8646c3a110 100644
--- a/native_client_sdk/src/libraries/ppapi_cpp_private/library.dsc
+++ b/native_client_sdk/src/libraries/ppapi_cpp_private/library.dsc
@@ -12,6 +12,7 @@
           'file_io_private.cc',
           'host_resolver_private.cc',
           'net_address_private.cc',
+          'pass_file_handle.cc',
           'tcp_socket_private.cc',
           'tcp_server_socket_private.cc',
           'udp_socket_private.cc',
diff --git a/native_client_sdk/src/libraries/ppapi_main/library.dsc b/native_client_sdk/src/libraries/ppapi_main/library.dsc
deleted file mode 100644
index c65e93036f..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/library.dsc
+++ /dev/null
@@ -1,31 +0,0 @@
-{
-  'TOOLS': ['newlib', 'glibc', 'pnacl'],
-  'TARGETS': [
-    {
-      'NAME': 'ppapi_main',
-      'TYPE': 'static-lib',
-      'SOURCES' : [
-        "ppapi_instance.cc",
-        "ppapi_instance2d.cc",
-        "ppapi_instance3d.cc",
-        "ppapi_main.cc",
-        "ppapi_queue.cc",
-      ],
-    }
-  ],
-  'HEADERS': [
-    {
-      'FILES': [
-        "ppapi_event.h",
-        "ppapi_instance.h",
-        "ppapi_instance2d.h",
-        "ppapi_instance3d.h",
-        "ppapi_main.h",
-        "ppapi_queue.h",
-      ],
-      'DEST': 'include/ppapi_main',
-    },
-  ],
-  'DEST': 'src',
-  'NAME': 'ppapi_main',
-}
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_event.h b/native_client_sdk/src/libraries/ppapi_main/ppapi_event.h
deleted file mode 100644
index d991192fe6..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_event.h
+++ /dev/null
@@ -1,81 +0,0 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-
-#ifndef PPAPI_MAIN_PPAPI_EVENT_H_
-#define PPAPI_MAIN_PPAPI_EVENT_H_
-
-#include "ppapi/c/pp_input_event.h"
-#include "ppapi/c/pp_point.h"
-#include "ppapi/c/pp_touch_point.h"
-#include "ppapi/c/ppb_input_event.h"
-
-#include "utils/macros.h"
-
-EXTERN_C_BEGIN
-
-/*
- * Event Structures
- *
- * The following event structures are based on the equivalent structs
- * defined in ppapi/c/ppb_input_event.h.
- *
- */
-
-// Generic Event
-typedef struct {
-  PP_InputEvent_Type event_type;
-  PP_TimeTicks time_ticks;
-  uint32_t modifiers;
-} PPAPIEvent;
-
-
-// Key Code Up/Down
-typedef struct {
-  PPAPIEvent event;
-
-  uint32_t key_code;
-} PPAPIKeyEvent;
-
-
-// Cooked Character Event
-typedef struct {
-  PPAPIEvent event;
-
-  char text[5];
-} PPAPICharEvent;
-
-
-// Mouse Event
-typedef struct {
-  PPAPIEvent event;
-
-  PP_InputEvent_MouseButton button;
-  struct PP_Point location;
-  struct PP_Point delta;
-} PPAPIMouseEvent;
-
-
-// Wheel Event
-typedef struct {
-  PPAPIEvent event;
-
-  PP_InputEvent_MouseButton button;
-  struct PP_FloatPoint delta;
-  uint32_t by_page;
-} PPAPIWheelEvent;
-
-
-// Touch Event
-#define MAX_TOUCH_POINTS 4
-typedef struct {
-  PPAPIEvent event;
-
-  uint32_t point_count;
-  struct PP_TouchPoint points[MAX_TOUCH_POINTS];
-} PPAPITouchEvent;
-
-EXTERN_C_END
-
-#endif  // PPAPI_MAIN_PPAPI_EVENT_H_
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance.cc b/native_client_sdk/src/libraries/ppapi_main/ppapi_instance.cc
deleted file mode 100644
index 2816c74817..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance.cc
+++ /dev/null
@@ -1,375 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <fcntl.h>
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-
-#include <cstdlib>
-#include <cstring>
-#include <map>
-#include <string>
-#include <vector>
-
-#include "nacl_io/kernel_wrap.h"
-#include "nacl_io/nacl_io.h"
-
-#include "ppapi/cpp/input_event.h"
-#include "ppapi/cpp/message_loop.h"
-#include "ppapi/cpp/rect.h"
-#include "ppapi/cpp/size.h"
-#include "ppapi/cpp/touch_point.h"
-#include "ppapi/cpp/var.h"
-
-#include "ppapi_main/ppapi_event.h"
-#include "ppapi_main/ppapi_instance.h"
-#include "ppapi_main/ppapi_main.h"
-
-
-PPAPIInstance* PPAPI_GetInstance() {
-  return static_cast<PPAPIInstance*>(PPAPI_GetInstanceObject());
-}
-
-struct StartInfo {
-  PPAPIInstance* inst_;
-  uint32_t argc_;
-  const char** argv_;
-};
-
-
-//
-// The starting point for 'main'.  We create this thread to hide the real
-// main pepper thread which must never be blocked.
-//
-void* PPAPIInstance::MainThreadThunk(void *info) {
-  StartInfo* si = static_cast<StartInfo*>(info);
-  int ret = si->inst_->MainThread(si->argc_, si->argv_);
-
-  printf("Main thread returned with %d.\n", ret);
-  for (uint32_t i = 0; i < si->argc_; i++) {
-    delete[] si->argv_[i];
-  }
-  delete[] si->argv_;
-  delete si;
-
-  return NULL;
-}
-
-//
-// Enabled with pm_use_main=False this creates a second thread where we
-// send all input, view change, buffer swap, etc... messages.  This allows us
-// avoid blocking the main pepper thread which would otherwise recieves these
-// messages, and may need to lock to act on them.
-//
-void *PPAPIInstance::EventThreadThunk(void *this_ptr) {
-  PPAPIInstance *pInst = static_cast<PPAPIInstance*>(this_ptr);
-  return pInst->EventThread();
-}
-
-
-//
-// The default implementation supports running a 'C' main.
-//
-int PPAPIInstance::MainThread(int argc, const char *argv[]) {
-  return ppapi_main(argc, argv);
-}
-
-
-//
-// The default implementation just waits to processes forwarded events.
-//
-void* PPAPIInstance::EventThread() {
-  render_loop_.AttachToCurrentThread();
-  render_loop_.Run();
-  printf("Event thread exiting.\n");
-  return NULL;
-}
-
-
-PPAPIInstance::PPAPIInstance(PP_Instance instance, const char *args[])
-    : pp::Instance(instance),
-      main_loop_(this),
-      has_focus_(false),
-      fullscreen_(this),
-      is_context_bound_(false),
-      callback_factory_(this),
-      use_main_thread_(true),
-      render_loop_(this) {
-
-  // Place PPAPI_MAIN_USE arguments into properties map
-  while (*args) {
-    std::string key = *args++;
-    std::string val = *args++;
-    properties_[key] = val;
-  }
-
-  RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE |
-                     PP_INPUTEVENT_CLASS_KEYBOARD |
-                     PP_INPUTEVENT_CLASS_WHEEL |
-                     PP_INPUTEVENT_CLASS_TOUCH);
-}
-
-PPAPIInstance::~PPAPIInstance() {}
-
-
-bool PPAPIInstance::Init(uint32_t arg,
-                         const char* argn[],
-                         const char* argv[]) {
-  StartInfo* si = new StartInfo;
-
-
-  si->inst_ = this;
-  si->argc_ = 1;
-  si->argv_ = new const char *[arg*2+1];
-  si->argv_[0] = NULL;
-
-  // Process arguments passed into Module INIT from JavaScript
-  for (uint32_t i=0; i < arg; i++) {
-    if (argv[i]) {
-      printf("ARG %s=%s\n", argn[i], argv[i]);
-    } else {
-      printf("ARG %s\n", argn[i]);
-    }
-
-    // If we start with PM prefix set the instance argument map
-    if (0 == strncmp(argn[i], "pm_", 3)) {
-      std::string key = argn[i];
-      std::string val = argv[i];
-      properties_[key] = val;
-      continue;
-    }
-
-    // If this is the 'src' tag, then get the NMF name.
-    if (!strcmp("src", argn[i])) {
-      char *name = new char[strlen(argv[i]) + 1];
-      strcpy(name, argv[i]);
-      si->argv_[0] = name;
-    }
-    else {
-      // Otherwise turn it into arguments
-      char *key = new char[strlen(argn[i]) + 3];
-      key[0] = '-';
-      key[1] = '-';
-      strcpy(&key[2], argn[i]);
-
-      si->argv_[si->argc_++] = key;
-      if (argv[i] && argv[i][0]) {
-        char *val = new char[strlen(argv[i]) + 1];
-        strcpy(val, argv[i]);
-        si->argv_[si->argc_++] = val;
-      }
-    }
-  }
-
-  // If src was not found, set the first arg to something
-  if (NULL == si->argv_[0]) {
-    char *name = new char[5];
-    strcpy(name, "NMF?");
-    si->argv_[0] = name;
-  }
-
-
-  if (ProcessProperties()) {
-    pthread_t main_thread;
-    int ret = pthread_create(&main_thread, NULL, MainThreadThunk,
-                             static_cast<void*>(si));
-    return ret == 0;
-  }
-
-  return false;
-}
-
-const char* PPAPIInstance::GetProperty(const char* key, const char* def) {
-  PropertyMap_t::iterator it = properties_.find(key);
-  if (it != properties_.end()) {
-    return it->second.c_str();
-  }
-  return def;
-}
-
-bool PPAPIInstance::ProcessProperties() {
-  const char* stdin_path = GetProperty("pm_stdin", "/dev/stdin");
-  const char* stdout_path = GetProperty("pm_stdout", "/dev/stdout");
-  const char* stderr_path = GetProperty("pm_stderr", "/dev/console3");
-  const char* queue_size = GetProperty("pm_queue_size", "1024");
-
-  // Build the event Queue with a minimum size of 4
-  uint32_t queue_size_int = atoi(queue_size);
-  if (queue_size_int < 4) queue_size_int = 4;
-  event_queue_.SetSize(queue_size_int);
-
-  // Enable NaCl IO to map STDIN, STDOUT, and STDERR
-  nacl_io_init_ppapi(PPAPI_GetInstanceId(), PPAPI_GetInterface);
-  int fd0 = open(stdin_path, O_RDONLY);
-  dup2(fd0, 0);
-
-  int fd1 = open(stdout_path, O_WRONLY);
-  dup2(fd1, 1);
-
-  int fd2 = open(stderr_path, O_WRONLY);
-  dup2(fd2, 2);
-
-  setvbuf(stderr, NULL, _IOLBF, 0);
-  setvbuf(stdout, NULL, _IOLBF, 0);
-
-  const char *use_main_str = GetProperty("pm_use_main", "true");
-  use_main_thread_ = !strcasecmp(use_main_str, "true");
-
-  // Create seperate thread for processing events.
-  printf("Events on main thread = %s.\n", use_main_str);
-  if (!use_main_thread_) {
-    pthread_t event_thread;
-    int ret = pthread_create(&event_thread, NULL, EventThreadThunk,
-                             static_cast<void*>(this));
-    return ret == 0;
-  }
-  return true;
-}
-
-void PPAPIInstance::HandleMessage(const pp::Var& message) {
-}
-
-bool PPAPIInstance::HandleInputEvent(const pp::InputEvent& event) {
-  PPAPIEvent* event_ptr;
-
-  // Remove a stale message if one is available
-  event_ptr = static_cast<PPAPIEvent*>(event_queue_.RemoveStaleMessage());
-  delete event_ptr;
-
-  switch (event.GetType()) {
-    case PP_INPUTEVENT_TYPE_MOUSEDOWN:
-    case PP_INPUTEVENT_TYPE_MOUSEUP:
-    case PP_INPUTEVENT_TYPE_MOUSEMOVE:
-    case PP_INPUTEVENT_TYPE_MOUSEENTER:
-    case PP_INPUTEVENT_TYPE_MOUSELEAVE: {
-      pp::MouseInputEvent mouse_event(event);
-      PPAPIMouseEvent* mouse_ptr = new PPAPIMouseEvent;
-      mouse_ptr->button = mouse_event.GetButton();
-      mouse_ptr->location = mouse_event.GetPosition().pp_point();
-      mouse_ptr->delta = mouse_event.GetMovement().pp_point();
-      event_ptr = &mouse_ptr->event;
-      break;
-    }
-
-    case PP_INPUTEVENT_TYPE_WHEEL: {
-      pp::WheelInputEvent wheel_event(event);
-      PPAPIWheelEvent* wheel_ptr = new PPAPIWheelEvent;
-      wheel_ptr->by_page =
-          static_cast<uint32_t>(wheel_event.GetScrollByPage());
-      wheel_ptr->delta = wheel_event.GetDelta().pp_float_point();
-      event_ptr = &wheel_ptr->event;
-      break;
-    }
-
-    case PP_INPUTEVENT_TYPE_CHAR: {
-       pp::KeyboardInputEvent key_event(event);
-       PPAPICharEvent* char_ptr = new PPAPICharEvent;
-       strncpy(char_ptr->text,
-               key_event.GetCharacterText().DebugString().c_str(),
-               sizeof(char_ptr->text));
-       event_ptr = &char_ptr->event;
-      break;
-    }
-
-    case PP_INPUTEVENT_TYPE_RAWKEYDOWN:
-    case PP_INPUTEVENT_TYPE_KEYDOWN:
-    case PP_INPUTEVENT_TYPE_KEYUP: {
-      pp::KeyboardInputEvent key_event(event);
-      PPAPIKeyEvent* key_ptr = new PPAPIKeyEvent;
-      key_ptr->key_code = key_event.GetKeyCode();
-      event_ptr = &key_ptr->event;
-      break;
-    }
-
-    case PP_INPUTEVENT_TYPE_TOUCHSTART:
-    case PP_INPUTEVENT_TYPE_TOUCHMOVE:
-    case PP_INPUTEVENT_TYPE_TOUCHEND:
-    case PP_INPUTEVENT_TYPE_TOUCHCANCEL: {
-      pp::TouchInputEvent touch_event(event);
-      PPAPITouchEvent* touch_ptr = new PPAPITouchEvent;
-      touch_ptr->point_count =
-          touch_event.GetTouchCount(PP_TOUCHLIST_TYPE_TOUCHES);
-      for (uint32_t cnt = 0; cnt < touch_ptr->point_count; cnt++) {
-          pp::TouchPoint *pnt = (pp::TouchPoint*) &touch_ptr->points[cnt];
-          *pnt = touch_event.GetTouchByIndex(PP_TOUCHLIST_TYPE_TOUCHES ,cnt);
-      }
-      event_ptr = &touch_ptr->event;
-      break;
-    }
-
-    default:
-      fprintf(stderr, "Unhandled event type %d\n", event.GetType());
-      return false;
-  }
-
-  event_ptr->event_type = event.GetType();
-  event_ptr->time_ticks = event.GetTimeStamp();
-  event_ptr->modifiers = event.GetModifiers();
-  if (!event_queue_.AddNewMessage(event_ptr)) {
-    printf("Warning:  Event Queue is full, dropping message.\n");
-  }
-  return true;
-}
-
-PPAPIEvent* PPAPIInstance::AcquireInputEvent() {
-  return static_cast<PPAPIEvent*>(event_queue_.AcquireTopMessage());
-}
-
-void PPAPIInstance::ReleaseInputEvent(PPAPIEvent* event) {
-  event_queue_.ReleaseTopMessage(event);
-}
-
-void PPAPIInstance::DidChangeView(const pp::View& view) {
-  pp::Size new_size = view.GetRect().size();
-  printf("View changed: %dx%d\n", new_size.width(), new_size.height());
-
-  // Build or update the 3D context when the view changes.
-  if (use_main_thread_) {
-    // If using the main thread, update the context immediately
-    BuildContext(0, new_size);
-  } else {
-    // If using a seperate thread, then post the message so we can build the
-    // context on the correct thread.
-    render_loop_.PostWork(callback_factory_.NewCallback(
-                          &PPAPIInstance::BuildContext, new_size));
-  }
-}
-
-void PPAPIInstance::DidChangeFocus(bool focus) {
-  has_focus_ = focus;
-}
-
-bool PPAPIInstance::ToggleFullscreen() {
-  // Ignore switch if in transition
-  if (!is_context_bound_)
-    return false;
-
-  if (fullscreen_.IsFullscreen()) {
-    if (!fullscreen_.SetFullscreen(false)) {
-      printf("Could not leave fullscreen mode\n");
-      return false;
-    }
-  } else {
-    if (!fullscreen_.SetFullscreen(true)) {
-      printf("Could not enter fullscreen mode\n");
-      return false;
-    }
-  }
-  return true;
-}
-
-// The default implementation calls the 'C' render function.
-void PPAPIInstance::Render(PP_Resource ctx, uint32_t width, uint32_t height) {
-}
-
-void PPAPIInstance::Flushed(int32_t result) {
-}
-
-void PPAPIInstance::BuildContext(int32_t result, const pp::Size& new_size) {
-  size_ = new_size;
-  printf("Resized: %dx%d.\n", size_.width(), size_.height());
-}
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance.h b/native_client_sdk/src/libraries/ppapi_main/ppapi_instance.h
deleted file mode 100644
index 1172cd8c45..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance.h
+++ /dev/null
@@ -1,106 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PPAPI_MAIN_PPAPI_INSTANCE_H_
-#define PPAPI_MAIN_PPAPI_INSTANCE_H_
-
-#include <map>
-
-#include "ppapi/c/pp_instance.h"
-#include "ppapi/cpp/fullscreen.h"
-#include "ppapi/cpp/instance.h"
-#include "ppapi/cpp/message_loop.h"
-#include "ppapi/cpp/mouse_lock.h"
-
-#include "ppapi/utility/completion_callback_factory.h"
-
-#include "ppapi_main/ppapi_event.h"
-#include "ppapi_main/ppapi_queue.h"
-
-
-typedef std::map<std::string, std::string> PropertyMap_t;
-
-class PPAPIInstance : public pp::Instance {
- public:
-  PPAPIInstance(PP_Instance instance, const char *args[]);
-  virtual ~PPAPIInstance();
-
-  //
-  // Callback functions triggered by Pepepr
-  //
-
-  // Called by the browser when the NaCl module is loaded and all ready to go.
-  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]);
-
-  // Called whenever the in-browser window changes size.
-  virtual void DidChangeView(const pp::View& view);
-
-  // Called by the browser when the NaCl canvas gets or loses focus.
-  virtual void DidChangeFocus(bool has_focus);
-
-  // Called by the browser to handle the postMessage() call in Javascript.
-  virtual void HandleMessage(const pp::Var& message);
-
-  // Called by the browser to handle incoming input events.
-  virtual bool HandleInputEvent(const pp::InputEvent& event);
-
-  // Called when the graphics flush completes
-  virtual void Flushed(int result);
-
-  // Called when we need to rebuild the Graphics device context.  This usually
-  // happens as a result of DidChangeView.
-  virtual void BuildContext(int32_t result, const pp::Size& new_size);
-
-  // Called with the current graphics context, current size and width, when
-  // the application is ready to render, either due to a newly build
-  // Context, or a successful Flush of the previous frame.
-  virtual void Render(PP_Resource ctx, uint32_t width, uint32_t height);
-
-  //
-  // Thread entry points
-  //
-  virtual int MainThread(int argc, const char* argv[]);
-  virtual void* EventThread();
-
-  //
-  // Request API
-  //
-  bool ToggleFullscreen();
-  virtual PPAPIEvent* AcquireInputEvent();
-  virtual void ReleaseInputEvent(PPAPIEvent* event);
-  static PPAPIInstance* GetInstance();
-
- protected:
-  // Called to run ppapi_main.
-  static void* MainThreadThunk(void *start_info);
-
-  // Called if message processing and rendering happens off the main thread.
-  static void* EventThreadThunk(void *this_ptr);
-
-  // Called by Init to processes default and embed tag arguments prior to
-  // launching the 'ppapi_main' thread.
-  virtual bool ProcessProperties();
-
-  // Returns value based on KEY or default.
-  const char* GetProperty(const char* key, const char* def = NULL);
-
- protected:
-  pp::MessageLoop main_loop_;
-  pp::Fullscreen fullscreen_;
-  pp::MessageLoop render_loop_;
-  pp::CompletionCallbackFactory<PPAPIInstance> callback_factory_;
-
-  PropertyMap_t properties_;
-  PPAPIQueue event_queue_;
-
-  pp::Size size_;
-  bool has_focus_;
-  bool is_context_bound_;
-  bool was_fullscreen_;
-  bool mouse_locked_;
-  bool use_main_thread_;
-};
-
-
-#endif  // PPAPI_MAIN_PPAPI_INSTANCE_H_
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance2d.cc b/native_client_sdk/src/libraries/ppapi_main/ppapi_instance2d.cc
deleted file mode 100644
index f6e54be62e..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance2d.cc
+++ /dev/null
@@ -1,87 +0,0 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <stdio.h>
-
-#include "ppapi/cpp/graphics_2d.h"
-#include "ppapi/cpp/message_loop.h"
-#include "ppapi/cpp/size.h"
-#include "ppapi/cpp/var.h"
-
-#include "ppapi/utility/completion_callback_factory.h"
-
-#include "ppapi_main/ppapi_instance2d.h"
-#include "ppapi_main/ppapi_main.h"
-
-
-void* PPAPI_CreateInstance2D(PP_Instance inst, const char *args[]) {
-  return static_cast<void*>(new PPAPIInstance2D(inst, args));
-}
-
-
-PPAPIInstance2D* PPAPIInstance2D::GetInstance2D() {
-  return static_cast<PPAPIInstance2D*>(PPAPI_GetInstanceObject());
-}
-
-
-void PPAPIInstance2D::Flushed(int result) {
-  if (result != 0) {
-    printf("Flush result=%d.\n", result);
-  }
-
-  if (is_context_bound_) {
-    Render(device_context_.pp_resource(), size_.width(), size_.height());
-
-    int result;
-    result = device_context_.Flush(callback_factory_.NewCallback(
-                                         &PPAPIInstance::Flushed));
-    if (result == PP_OK_COMPLETIONPENDING) return;
-    printf("Failed Flush with %d.\n", result);
-  }
-
-  // Failed to draw, so add a callback for the future.  This could
-  // an application choice or the browser dealing with an event such as
-  // fullscreen toggle.  We add a delay of 100ms (to prevent burnning CPU
-  // in cases where the context will not be available for a while.
-  pp::MessageLoop::GetCurrent().PostWork(callback_factory_.NewCallback(
-                                         &PPAPIInstance::Flushed), 100);
-}
-
-void PPAPIInstance2D::BuildContext(int32_t result, const pp::Size& new_size) {
-  printf("Building context.\n");
-
-  size_ = new_size;
-  device_context_ = pp::Graphics2D(this, size_ ,true);
-  printf("Got Context!\n");
-
-  is_context_bound_ = BindGraphics(device_context_);
-  printf("Context is bound=%d\n", is_context_bound_);
-
-  if (is_context_bound_) {
-    PPAPIBuildContext(size_.width(), size_.height());
-    device_context_.Flush(callback_factory_.NewCallback(
-                          &PPAPIInstance::Flushed));
-  } else {
-    fprintf(stderr, "Failed to bind context for %dx%d.\n", size_.width(),
-            size_.height());
-  }
-}
-
-// The default implementation calls the 'C' render function.
-void PPAPIInstance2D::Render(PP_Resource ctx, uint32_t width,
-                             uint32_t height) {
-  PPAPIRender(ctx, width, height);
-}
-
-PPAPIInstance2D::PPAPIInstance2D(PP_Instance instance, const char *args[])
-    : PPAPIInstance(instance, args) {
-}
-
-
-PPAPIInstance2D::~PPAPIInstance2D() {
-  if (is_context_bound_) {
-    is_context_bound_ = false;
-    // Cleanup code?
-  }
-}
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance2d.h b/native_client_sdk/src/libraries/ppapi_main/ppapi_instance2d.h
deleted file mode 100644
index ac600c2c27..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance2d.h
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PPAPI_MAIN_PPAPI_INSTANCE2D_H_
-#define PPAPI_MAIN_PPAPI_INSTANCE2D_H_
-
-#include "ppapi/c/pp_instance.h"
-
-#include "ppapi/cpp/graphics_2d.h"
-#include "ppapi/cpp/instance.h"
-#include "ppapi/cpp/size.h"
-
-#include "ppapi_main/ppapi_instance.h"
-
-
-class PPAPIInstance2D : public PPAPIInstance {
- public:
-  PPAPIInstance2D(PP_Instance instance, const char *args[]);
-  virtual ~PPAPIInstance2D();
-
-  // Called when we need to rebuild the context
-  virtual void BuildContext(int32_t result, const pp::Size& new_size);
-
-  // Called whenever a swap takes place
-  virtual void Flushed(int result);
-
-  virtual void Render(PP_Resource ctx, uint32_t width, uint32_t height);
-  static PPAPIInstance2D* GetInstance2D();
-
- protected:
-  pp::Graphics2D device_context_;
-};
-
-
-#endif  // PPAPI_MAIN_PPAPI_INSTANCE2D_H_
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance3d.cc b/native_client_sdk/src/libraries/ppapi_main/ppapi_instance3d.cc
deleted file mode 100644
index 43cad475d3..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance3d.cc
+++ /dev/null
@@ -1,144 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <stdio.h>
-
-#include "GLES2/gl2.h"
-
-#include "ppapi/cpp/graphics_3d.h"
-#include "ppapi/cpp/size.h"
-#include "ppapi/gles2/gl2ext_ppapi.h"
-#include "ppapi/utility/completion_callback_factory.h"
-
-#include "ppapi_main/ppapi_instance.h"
-#include "ppapi_main/ppapi_instance3d.h"
-#include "ppapi_main/ppapi_main.h"
-
-
-void* PPAPI_CreateInstance3D(PP_Instance inst, const char *args[]) {
-  return static_cast<void*>(new PPAPIInstance3D(inst, args));
-}
-
-
-int32_t *PPAPIGet3DAttribs(uint32_t width, uint32_t height) {
-  static int32_t attribs[] = {
-    PP_GRAPHICS3DATTRIB_WIDTH, 0,
-    PP_GRAPHICS3DATTRIB_HEIGHT, 0,
-    PP_GRAPHICS3DATTRIB_ALPHA_SIZE, 8,
-    PP_GRAPHICS3DATTRIB_DEPTH_SIZE, 24,
-    PP_GRAPHICS3DATTRIB_STENCIL_SIZE, 8,
-    PP_GRAPHICS3DATTRIB_SAMPLES, 0,
-    PP_GRAPHICS3DATTRIB_SAMPLE_BUFFERS, 0,
-    PP_GRAPHICS3DATTRIB_NONE
-  };
-
-  attribs[1] = width;
-  attribs[3] = height;
-
-  printf("Building attribs for %dx%d.\n", width, height);
-  return attribs;
-}
-
-void PPAPIBuildContext(uint32_t width, uint32_t height) {
-  glViewport(0, 0, width, height);
-  glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
-  printf("Built Context %d, %d.\n", width, height);
-}
-
-
-PPAPIInstance3D* PPAPIInstance3D::GetInstance3D() {
-  return static_cast<PPAPIInstance3D*>(PPAPI_GetInstanceObject());
-}
-
-void PPAPIInstance3D::Flushed(int result) {
-  if (result != 0) {
-    printf("Swapped result=%d.\n", result);
-  }
-
-  if (is_context_bound_) {
-    Render(device_context_.pp_resource(), size_.width(), size_.height());
-
-    int result;
-    result = device_context_.SwapBuffers(callback_factory_.NewCallback(
-                                         &PPAPIInstance::Flushed));
-    if (result == PP_OK_COMPLETIONPENDING) return;
-    printf("Failed swap with %d.\n", result);
-  }
-
-  // Failed to draw, so add a callback for the future.  This could
-  // an application choice or the browser dealing with an event such as
-  // fullscreen toggle.  We add a delay of 100ms (to prevent burnning CPU
-  // in cases where the context will not be available for a while.
-  pp::MessageLoop::GetCurrent().PostWork(callback_factory_.NewCallback(
-                                         &PPAPIInstance::Flushed), 100);
-}
-
-void PPAPIInstance3D::BuildContext(int32_t result, const pp::Size& new_size) {
-  printf("Building context.\n");
-
-  // If already bound, try to resize to avoid the need to rebuild the context.
-  if (is_context_bound_) {
-    // If the size is correct, then just skip this request.
-    if (new_size == size_) {
-      printf("Skipped building context, same size as bound.\n");
-      return;
-    }
-    int err = device_context_.ResizeBuffers(new_size.width(),
-                                            new_size.height());
-
-    // Resized the context, we are done
-    if (err == PP_OK) {
-      size_ = new_size;
-      fprintf(stderr, "Resized context from %dx%d to %dx%d",
-              size_.width(), size_.height(), new_size.width(),
-              new_size.height());
-      PPAPIBuildContext(size_.width(), size_.height());
-      return;
-    }
-
-    // Failed to resize, fall through and start from scratch
-    fprintf(stderr, "Failed to resize buffer from %dx%d to %dx%d",
-            size_.width(), size_.height(), new_size.width(), new_size.height());
-
-    is_context_bound_ = false;
-  }
-
-  printf("Calling create context....\n");
-  size_ = new_size;
-  device_context_ = pp::Graphics3D(this, PPAPIGet3DAttribs(size_.width(),
-                                                           size_.height()));
-  printf("Got Context!\n");
-  is_context_bound_ = BindGraphics(device_context_);
-  printf("Context is bound=%d\n", is_context_bound_);
-
-  // Set the context regardless to make sure we have a valid one
-  glSetCurrentContextPPAPI(device_context_.pp_resource());
-  if (is_context_bound_) {
-    PPAPIBuildContext(size_.width(), size_.height());
-    device_context_.SwapBuffers(callback_factory_.NewCallback(
-                                &PPAPIInstance::Flushed));
-  } else {
-    fprintf(stderr, "Failed to bind context for %dx%d.\n", size_.width(),
-            size_.height());
-  }
-}
-
-// The default implementation calls the 'C' render function.
-void PPAPIInstance3D::Render(PP_Resource ctx, uint32_t width,
-                             uint32_t height) {
-  PPAPIRender(ctx, width, height);
-}
-
-PPAPIInstance3D::PPAPIInstance3D(PP_Instance instance, const char *args[])
-    : PPAPIInstance(instance, args) {
-  glInitializePPAPI(pp::Module::Get()->get_browser_interface());
-}
-
-
-PPAPIInstance3D::~PPAPIInstance3D() {
-  if (is_context_bound_) {
-    is_context_bound_ = false;
-    // Cleanup code?
-  }
-}
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance3d.h b/native_client_sdk/src/libraries/ppapi_main/ppapi_instance3d.h
deleted file mode 100644
index 410b952170..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_instance3d.h
+++ /dev/null
@@ -1,40 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PPAPI_MAIN_PPAPI_INSTANCE3D_H_
-#define PPAPI_MAIN_PPAPI_INSTANCE3D_H_
-
-#include <map>
-
-#include "ppapi/c/pp_instance.h"
-#include "ppapi/c/pp_resource.h"
-
-#include "ppapi/cpp/graphics_3d.h"
-#include "ppapi/cpp/instance.h"
-#include "ppapi/cpp/size.h"
-
-#include "ppapi_main/ppapi_instance.h"
-
-
-class PPAPIInstance3D : public PPAPIInstance {
- public:
-  PPAPIInstance3D(PP_Instance instance, const char *args[]);
-  virtual ~PPAPIInstance3D();
-
-  // Called when we need to rebuild the context
-  virtual void BuildContext(int32_t result, const pp::Size& new_size);
-
-  // Called whenever a swap takes place
-  virtual void Flushed(int result);
-
-  virtual void Render(PP_Resource ctx, uint32_t width, uint32_t height);
-  static PPAPIInstance3D* GetInstance3D();
-
- protected:
-  pp::Graphics3D device_context_;
-
-};
-
-
-#endif  // PPAPI_MAIN_PPAPI_INSTANCE3D_H_
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_main.cc b/native_client_sdk/src/libraries/ppapi_main/ppapi_main.cc
deleted file mode 100644
index 3d666c910f..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_main.cc
+++ /dev/null
@@ -1,71 +0,0 @@
-/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "ppapi/c/pp_instance.h"
-#include "ppapi/c/pp_module.h"
-
-#include "ppapi/cpp/instance.h"
-#include "ppapi/cpp/module.h"
-
-#include "ppapi_main/ppapi_instance.h"
-#include "ppapi_main/ppapi_instance3d.h"
-#include "ppapi_main/ppapi_main.h"
-
-
-static pp::Instance* s_Instance = NULL;
-
-
-// Helpers to access PPAPI interfaces
-void* PPAPI_GetInstanceObject() {
-  return s_Instance;
-}
-
-PP_Instance PPAPI_GetInstanceId() {
-  return s_Instance->pp_instance();
-}
-
-const void* PPAPI_GetInterface(const char *name) {
-  return pp::Module::Get()->GetBrowserInterface(name);
-}
-
-void* PPAPI_CreateInstance(PP_Instance inst, const char *args[]) {
-  return static_cast<void*>(new PPAPIInstance(inst, args));
-}
-
-PPAPIEvent* PPAPI_AcquireEvent() {
-  return static_cast<PPAPIInstance*>(s_Instance)->AcquireInputEvent();
-}
-
-void PPAPI_ReleaseEvent(PPAPIEvent* event) {
-  static_cast<PPAPIInstance*>(s_Instance)->ReleaseInputEvent(event);
-}
-
-
-/// The Module class.  The browser calls the CreateInstance() method to create
-/// an instance of your NaCl module on the web page.  The browser creates a new
-/// instance for each <embed> tag with type="application/x-nacl".
-class PPAPIMainModule : public pp::Module {
- public:
-  PPAPIMainModule() : pp::Module() {}
-  virtual ~PPAPIMainModule() {}
-
-  virtual pp::Instance* CreateInstance(PP_Instance instance) {
-    s_Instance = static_cast<pp::Instance*>(UserCreateInstance(instance));
-    return s_Instance;
-  }
-};
-
-namespace pp {
-/// Factory function called by the browser when the module is first loaded.
-/// The browser keeps a singleton of this module.  It calls the
-/// CreateInstance() method on the object you return to make instances.  There
-/// is one instance per <embed> tag on the page.  This is the main binding
-/// point for your NaCl module with the browser.
-Module* CreateModule() {
-  return new PPAPIMainModule();
-}
-
-}  // namespace pp
-
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_main.h b/native_client_sdk/src/libraries/ppapi_main/ppapi_main.h
deleted file mode 100644
index 2f2c4e31d8..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_main.h
+++ /dev/null
@@ -1,62 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PPAPI_MAIN_PPAPI_MAIN_H_
-#define PPAPI_MAIN_PPAPI_MAIN_H_
-
-#include "ppapi/c/pp_instance.h"
-#include "ppapi/c/pp_module.h"
-#include "ppapi_main/ppapi_event.h"
-
-#include "utils/macros.h"
-
-EXTERN_C_BEGIN
-
-// Prototype for 'main' which will get called on startup
-int ppapi_main(int argc, const char *argv[]);
-
-// Provided by "main" module, use one of the macros below
-void* UserCreateInstance(PP_Instance inst);
-
-// Helpers to access PPAPI interfaces
-void* PPAPI_GetInstanceObject();
-PP_Instance PPAPI_GetInstanceId();
-const void* PPAPI_GetInterface(const char *name);
-
-// Provided by library for basic instance types
-void* PPAPI_CreateInstance(PP_Instance inst, const char *args[]);
-void* PPAPI_CreateInstance2D(PP_Instance inst, const char *args[]);
-void* PPAPI_CreateInstance3D(PP_Instance inst, const char *args[]);
-
-// Event APIs
-PPAPIEvent* PPAPI_AcquireEvent();
-void PPAPI_ReleaseEvent(PPAPIEvent* event);
-
-// Functions for Graphic Instances
-int32_t *PPAPIGet3DAttribs(uint32_t width, uint32_t height);
-void PPAPIBuildContext(uint32_t width, uint32_t height);
-void PPAPIRender(PP_Resource ctx, uint32_t width, uint32_t height);
-
-
-EXTERN_C_END
-
-#define PPAPI_MAIN_DEFAULT_ARGS  NULL, NULL
-
-#define PPAPI_MAIN_USE(factory, ...)              \
-void* UserCreateInstance(PP_Instance inst) {      \
-  static const char *params[] = { __VA_ARGS__ };  \
-  return factory(inst, params);                   \
-}
-
-#define PPAPI_MAIN_WITH_DEFAULT_ARGS \
-  PPAPI_MAIN_USE(PPAPI_CreateInstance, PPAPI_MAIN_DEFAULT_ARGS)
-
-#define PPAPI_MAIN_3D_WITH_DEFAULT_ARGS \
-  PPAPI_MAIN_USE(PPAPI_CreateInstance3D, PPAPI_MAIN_DEFAULT_ARGS)
-
-#define PPAPI_MAIN_WITH_ARGS(...) \
-  PPAPI_MAIN_USE(PPAPI_CreateInstance, __VA_ARGS__)
-
-
-#endif  // PPAPI_MAIN_PPAPI_MAIN_H_
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_queue.cc b/native_client_sdk/src/libraries/ppapi_main/ppapi_queue.cc
deleted file mode 100644
index 9ecce6680e..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_queue.cc
+++ /dev/null
@@ -1,97 +0,0 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <assert.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "ppapi_main/ppapi_queue.h"
-
-PPAPIQueue::PPAPIQueue()
-  : read_(0),
-    write_(0),
-    freed_(0),
-    size_(0),
-    array_(NULL) { }
-
-PPAPIQueue::~PPAPIQueue() {
-  // Messages may be leaked if the queue is not empty.
-  assert(read_ == write_);
-
-  delete[] array_;
-}
-
-bool PPAPIQueue::SetSize(uint32_t queue_size) {
-  assert(queue_size > 0);
-
-  if (array_) return false;
-
-  array_ = new void*[queue_size];
-  size_ = queue_size;
-
-  memset(array_, 0, sizeof(void*) * queue_size);
-  return true;
-}
-
-bool PPAPIQueue::AddNewMessage(void* msg) {
-  // Writing a NULL message is illegal
-  assert(array_ != NULL);
-  assert(msg != NULL);
-
-  // If the slot not empty, the queue must be full.  Calling RemoveStaleMessage
-  // may create space by freeing messages that have already been read.
-  if (array_[write_] != NULL) return false;
-
-  // Write to the spot
-  array_[write_] = msg;
-
-  // Fence to make sure the payload and payload pointer are visible.
-  // Since Win32 is x86 which provides ordered writes, we don't need to
-  // synchronize in that case.
-#ifndef WIN32
-  __sync_synchronize();
-#endif
-
-  // Increment the write pointer, to signal it's readable.
-  write_ = (write_ + 1) % size_;
-  return true;
-}
-
-void* PPAPIQueue::RemoveStaleMessage() {
-  assert(array_ != NULL);
-
-  // If freed and read pointer are equal, this hasn't been read yet
-  if (freed_ == read_) return NULL;
-
-  assert(array_[freed_] != NULL);
-
-  void* ret = array_[freed_];
-  array_[freed_] = NULL;
-
-  freed_ = (freed_ + 1) % size_;
-  return ret;
-}
-
-void* PPAPIQueue::AcquireTopMessage() {
-  // Assert that we aren't already reading a message.
-  assert(last_msg_ == NULL);
-
-  // If read and write pointers are equal, the queue is empty.
-  if (read_ == write_) return NULL;
-
-  // Track the last message to look for illegal API use.
-  last_msg_ = array_[read_];
-  return last_msg_;
-}
-
-void PPAPIQueue::ReleaseTopMessage(void* msg) {
-  // Verify we currently acquire message.
-  assert(msg != NULL);
-  assert(msg == last_msg_);
-
-  last_msg_ = NULL;
-
-  // Signal that the message can be freed.
-  read_ = (read_ + 1) % size_;
-}
diff --git a/native_client_sdk/src/libraries/ppapi_main/ppapi_queue.h b/native_client_sdk/src/libraries/ppapi_main/ppapi_queue.h
deleted file mode 100644
index f022dcf0b3..0000000000
--- a/native_client_sdk/src/libraries/ppapi_main/ppapi_queue.h
+++ /dev/null
@@ -1,84 +0,0 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-
-#ifndef PPAPI_MAIN_PPAPI_QUEUE_H
-#define PPAPI_MAIN_PPAPI_QUEUE_H
-
-#include <stdint.h>
-
-//
-// PPAPIQueue
-//
-// PPAPIQueue is a single producer/single consumer lockless queue.  This
-// implementation is PPAPI friendly because it prevents the main thread from
-// ever needing to lock.   In addition, allocation and destruction of messages
-// happens on the same thread, allowing for lockless message allocation as well.
-//
-// Messages pass through four states in order:
-//   AddNewMessage - The message is added to the queue by the producer
-//   and the memory is fenced to ensure it is visible.  Once the fence
-//   returns, the write pointer is incremented to signal it's available to
-//   the consumer.  NOTE: NULL messages are illegal.
-//
-//   AcquireTopMessage - Next the message is acquired by the consumer thread.
-//   At this point, the consumer is considered to be examining the payload so
-//   we do not increment the read pointer yet to prevent deletion.  NOTE: it
-//   is illegal to acquire the next message until the previous one is released.
-//
-//   ReleaseTopMessage - Now the consumer signals that it is no longer looking
-//   at the message by incremented the read pointer.  The producer is free to
-//   release or reuse the payload.
-//
-//   RemoveStaleMessage - The message is no longer visible to the consumer, so
-//   it is returned to the producer to be reused or destroyed.  It's location
-//   in the queue is set to NULL to signal that a new message may be added in
-//   that slot.
-//
-class PPAPIQueue {
- public:
-  PPAPIQueue();
-  ~PPAPIQueue();
-
-  //
-  // Producer API
-  //
-  // First, the producer must set the queue size before any operation can
-  // take place.  Next, before adding a message, clear space in the queue,
-  // by removing stale messages.  Adding a new message will return TRUE if
-  // space is available, otherwise FALSE is returned and it's up to the
-  // application developer to decide what to do.
-  //
-  bool SetSize(uint32_t queue_size);
-  bool AddNewMessage(void* msg);
-  void* RemoveStaleMessage();
-
-  //
-  // Consumer API
-  //
-  // The reader will attempt to Acquire the top message, if one is not
-  // available NULL will be returned.  Once the consumer is done with the
-  // message, ReleaseTopMessage is called to signal that the payload is no
-  // longer visible to the consumer and can be recycled or destroyed.
-  // Since messages are freed in order, it is required that messages are
-  // consumed in order.  For this reason, it is illegal to call Acquire again
-  // after a non-NULL message pointer is returned, until Release is called on
-  // the old message.  This means the consumer can only look at one message
-  // at a time.  To look at multiple messages at once, the consumer would
-  // need to make a copy and release the top message.
-  //
-  void* AcquireTopMessage();
-  void ReleaseTopMessage(void* msg);
-
- private:
-  uint32_t read_;
-  uint32_t write_;
-  uint32_t freed_;
-  uint32_t size_;
-  void*  last_msg_;
-  void** array_;
-};
-
-
-#endif  // PPAPI_MAIN_PPAPI_QUEUE_H
diff --git a/native_client_sdk/src/libraries/ppapi_simple/library.dsc b/native_client_sdk/src/libraries/ppapi_simple/library.dsc
new file mode 100644
index 0000000000..613a585227
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/library.dsc
@@ -0,0 +1,28 @@
+{
+  'TOOLS': ['newlib', 'glibc', 'pnacl'],
+  'TARGETS': [
+    {
+      'NAME' : 'ppapi_simple',
+      'TYPE' : 'lib',
+      'SOURCES' : [
+        "ps.cc",
+        "ps_event.cc",
+        "ps_instance.cc",
+        "ps_main.cc",
+      ],
+    }
+  ],
+  'HEADERS': [
+    {
+      'FILES': [
+        "ps.h",
+        "ps_event.h",
+        "ps_instance.h",
+        "ps_main.h",
+      ],
+      'DEST': 'include/ppapi_simple',
+    },
+  ],
+  'DEST': 'src',
+  'NAME': 'ppapi_simple',
+}
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps.cc b/native_client_sdk/src/libraries/ppapi_simple/ps.cc
new file mode 100644
index 0000000000..eba3c4030b
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps.cc
@@ -0,0 +1,51 @@
+/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "ppapi/c/pp_instance.h"
+#include "ppapi/c/pp_module.h"
+
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+
+#include "ppapi_simple/ps.h"
+
+static pp::Instance* s_Instance = NULL;
+
+PP_Instance PSGetInstanceId() {
+  return s_Instance->pp_instance();
+}
+
+const void* PSGetInterface(const char *name) {
+  return pp::Module::Get()->GetBrowserInterface(name);
+}
+
+
+// The Module class.  The browser calls the CreateInstance() method to create
+// an instance of your NaCl module on the web page.  The browser creates a new
+// instance for each <embed> tag with type="application/x-nacl".
+class PSModule : public pp::Module {
+ public:
+  PSModule() : pp::Module() {}
+  virtual ~PSModule() {}
+
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    s_Instance = static_cast<pp::Instance*>(PSUserCreateInstance(instance));
+    return s_Instance;
+  }
+};
+
+namespace pp {
+
+// Factory function called by the browser when the module is first loaded.
+// The browser keeps a singleton of this module.  It calls the
+// CreateInstance() method on the object you return to make instances.  There
+// is one instance per <embed> tag on the page.  This is the main binding
+// point for your NaCl module with the browser.
+Module* CreateModule() {
+  return new PSModule();
+}
+
+}  // namespace pp
+
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps.h b/native_client_sdk/src/libraries/ppapi_simple/ps.h
new file mode 100644
index 0000000000..1d7b2543ae
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps.h
@@ -0,0 +1,113 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PPAPI_SIMPLE_PS_H_
+#define PPAPI_SIMPLE_PS_H_
+
+#include "ppapi/c/pp_instance.h"
+#include "sdk_util/macros.h"
+
+EXTERN_C_BEGIN
+
+/**
+ * The ppapi_simple library simplifies the use of the Pepper interfaces by
+ * providing a more traditional 'C' or 'C++' style framework.  The library
+ * creates an PSInstance derived object based on the ppapi_cpp library and
+ * initializes the nacl_io library to provide a POSIX friendly I/O environment.
+ *
+ * In order to provide a standard blocking environment, the library will hide
+ * the actual "Pepper Thread" which is the thread that standard events
+ * such as window resize, mouse keyboard, or other inputs arrive.  To prevent
+ * blocking, instead we enqueue these events onto a thread safe linked list
+ * and expect them to be processed on a new thread.  In addition, the library
+ * will automatically start a new thread on which can be used effectively
+ * as a "main" entry point.
+ *
+ * For C style development, the PPAPI_SIMPLE_REGISTER_MAIN(XX) macros provide a
+ * mechanism to register the entry an point for "main".  All events are pushed
+ * onto an event queue which can then be pulled from this new thread.
+ * NOTE: The link will still need libstdc++ and libppapi_cpp since the library
+ * is still creating a C++ object which does the initialization work and
+ * forwards the events.
+ *
+ * For C++ style development, use the ppapi_simple_instance.h,
+ * ppapi_simple_instance_2d.h, and ppapi_simple_instance_3d.h headers as
+ * a base class, and overload the appropriate virtual functions such as
+ * Main, ChangeContext, or Render.
+ */
+
+/**
+ * PSGetInstanceId
+ *
+ * Return the PP_Instance id of this instance of the module.  This is required
+ * by most of the Pepper resource creation routines.
+ */
+PP_Instance PSGetInstanceId();
+
+
+/**
+ * PSGetInterface
+ *
+ * Return the Pepper instance referred to by 'name'.  Will return a pointer
+ * to the interface, or NULL if not found or not available.
+ */
+const void* PSGetInterface(const char *name);
+
+
+/**
+ * PSUserCreateInstance
+ *
+ * Prototype for the user provided function which creates and configures
+ * the instance object.  This function is defined by one of the macros below,
+ * or by the equivalent macro in one of the other headers.  For 'C'
+ * development, one of the basic instances which support C callback are used.
+ * For C++, this function should instantiate the user defined instance.  See
+ * the two macros below.
+ */
+extern void* PSUserCreateInstance(PP_Instance inst);
+
+
+/**
+ * PPAPI_SIMPLE_DECLARE_PARAMS
+ *
+ * Macro for creating the param string array.  Used by the Factory macros
+ * to enable wrapping of the param array with terminating NULL, NULL.
+ */
+#define PPAPI_SIMPLE_DECLARE_PARAMS(params, ...)     \
+  static const char* params[] = { __VA_ARGS__ };
+
+
+/**
+ * PPAPI_SIMPLE_USE_MAIN
+ *
+ * For use with C projects, this macro calls the provided factory with
+ * configuration information and optional extra arguments which are passed to
+ * the 'main' function.  See the appropriate ppapi_simple_main(XX).h header.
+ */
+#define PPAPI_SIMPLE_USE_MAIN(factory, func, ...)                   \
+void* PSUserCreateInstance(PP_Instance inst) {                      \
+  PPAPI_SIMPLE_DECLARE_PARAMS(params, ##__VA_ARGS__, NULL, NULL)    \
+  return factory(inst, func, params);                               \
+}
+
+
+/**
+ * PPAPI_SIMPLE_USE_CLASS
+ *
+ * For use with C++ projects, this macro instantiates the provided class
+ * passing it back to the generic module initialization code.  Simply derive
+ * a class from the appropriate ppapi_simple_instance(XX).h and pass the
+ * class name here.
+ */
+#define PPAPI_SIMPLE_USE_CLASS(classname, ...)                     \
+void* PSUserCreateInstance(PP_Instance inst) {                     \
+  PPAPI_SIMPLE_DECLARE_PARAMS(params, ##__VA_ARGS__, NULL, NULL)   \
+  return (void *) new classname(inst, params);                     \
+}
+
+EXTERN_C_END
+
+
+#endif  // PPAPI_SIMPLE_PPAPI_SIMPLE_H
+
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps_event.cc b/native_client_sdk/src/libraries/ppapi_simple/ps_event.cc
new file mode 100644
index 0000000000..ac68fe9b59
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps_event.cc
@@ -0,0 +1,45 @@
+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "ppapi/c/pp_instance.h"
+#include "ppapi/c/pp_module.h"
+
+#include "ppapi_simple/ps_event.h"
+#include "ppapi_simple/ps_instance.h"
+#include "ppapi_simple/ps_main.h"
+
+
+void PSEventPost(PSEventType type) {
+  PSInstance::GetInstance()->PostEvent(type);
+}
+
+void PSEventPostBool(PSEventType type, PP_Bool state) {
+  PSInstance::GetInstance()->PostEvent(type, state);
+}
+
+void PSEventPostVar(PSEventType type, struct PP_Var var) {
+  PSInstance::GetInstance()->PostEvent(type, var);
+}
+
+void PSEventPostResource(PSEventType type, PP_Resource resource) {
+  PSInstance::GetInstance()->PostEvent(type, resource);
+}
+
+PSEvent* PSEventTryAcquire() {
+  return PSInstance::GetInstance()->TryAcquireEvent();
+}
+
+PSEvent* PSEventWaitAcquire() {
+  return PSInstance::GetInstance()->WaitAcquireEvent();
+}
+
+void PSEventRelease(PSEvent* event) {
+  PSInstance::GetInstance()->ReleaseEvent(event);
+}
+
+void PSEventSetFilter(PSEventTypeMask filter) {
+  PSInstance::GetInstance()->SetEnabledEvents(filter);
+}
+
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps_event.h b/native_client_sdk/src/libraries/ppapi_simple/ps_event.h
new file mode 100644
index 0000000000..563832c703
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps_event.h
@@ -0,0 +1,95 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+
+#ifndef PPAPI_SIMPLE_PS_EVENT_H_
+#define PPAPI_SIMPLE_PS_EVENT_H_
+
+#include "ppapi/c/pp_bool.h"
+#include "ppapi/c/pp_resource.h"
+#include "ppapi/c/pp_var.h"
+
+#include "sdk_util/macros.h"
+
+EXTERN_C_BEGIN
+
+/**
+ * PSEvent
+ *
+ * The PSEvent system provides an in-order event processing mechanism.
+ * As Pepper events such as input, or focus and view changes arrive on the
+ * main pepper thread, they are placed on various FIFOs based on event type.
+ * For any given event type, only a single thread will process those events.
+ *
+ * By default, the "EventThread" will receive all messages.  However any thread
+ * can call PSRequestEventsType to request that all new events of that type
+ * are placed on that particular thread's queue.
+ *
+ * This allows the developer to choose which threads handle which event types
+ * while keeping all events belonging to a particular thread in order.  This
+ * is useful, for example, in the case of graphics to synchronize the size
+ * of the graphics context, with mouse clicks to correctly interpret location.
+ */
+
+
+typedef enum {
+  /* Mask off all events. */
+  PSE_NONE = 0,
+
+  /* From HandleInputEvent, conatins an input resource. */
+  PSE_INSTANCE_HANDLEINPUT = 1,
+
+  /* From HandleMessage, contains a PP_Var. */
+  PSE_INSTANCE_HANDLEMESSAGE = 2,
+
+  /* From DidChangeView, contains a view resource */
+  PSE_INSTANCE_DIDCHANGEVIEW = 4,
+
+  /* From DidChangeFocus, contains a PP_Bool with the current focus state. */
+  PSE_INSTANCE_DIDCHANGEFOCUS = 8,
+
+  /* When the 3D context is lost, no resource. */
+  PSE_GRAPHICS3D_GRAPHICS3DCONTEXTLOST = 16,
+
+  /* When the mouse lock is lost. */
+  PSE_MOUSELOCK_MOUSELOCKLOST = 32,
+
+  /* Enable all events. */
+  PSE_ALL = -1,
+} PSEventType;
+
+typedef uint32_t PSEventTypeMask;
+
+// Generic Event
+typedef struct {
+  PSEventType type;
+  union {
+    PP_Bool as_bool;
+    PP_Resource as_resource;
+    struct PP_Var as_var;
+  };
+} PSEvent;
+
+
+/**
+ * Function for queuing, acquiring, and releasing events.
+ */
+PSEvent* PSEventTryAcquire();
+PSEvent* PSEventWaitAcquire();
+void PSEventRelease(PSEvent* event);
+void PSEventSetFilter(PSEventTypeMask mask);
+
+/**
+ * Creates and adds an event of the specified type to the event queue if
+ * that event type is not currently filtered.
+ */
+void PSEventPost(PSEventType type);
+void PSEventPostBool(PSEventType type, PP_Bool state);
+void PSEventPostVar(PSEventType type, struct PP_Var var);
+void PSEventPostResource(PSEventType type, PP_Resource resource);
+
+EXTERN_C_END
+
+#endif  // PPAPI_SIMPLE_PS_EVENT_H_
+
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps_instance.cc b/native_client_sdk/src/libraries/ppapi_simple/ps_instance.cc
new file mode 100644
index 0000000000..120378765f
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps_instance.cc
@@ -0,0 +1,357 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <cstdlib>
+#include <cstring>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "nacl_io/kernel_wrap.h"
+#include "nacl_io/nacl_io.h"
+
+#include "ppapi/c/ppb_var.h"
+
+#include "ppapi/cpp/input_event.h"
+#include "ppapi/cpp/message_loop.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/rect.h"
+#include "ppapi/cpp/size.h"
+#include "ppapi/cpp/touch_point.h"
+#include "ppapi/cpp/var.h"
+
+#include "ppapi_simple/ps_event.h"
+#include "ppapi_simple/ps_instance.h"
+#include "ppapi_simple/ps_main.h"
+
+static PSInstance* s_InstanceObject = NULL;
+
+PSInstance* PSInstance::GetInstance() {
+  return s_InstanceObject;
+}
+
+struct StartInfo {
+  PSInstance* inst_;
+  uint32_t argc_;
+  const char** argv_;
+};
+
+
+// The starting point for 'main'.  We create this thread to hide the real
+// main pepper thread which must never be blocked.
+void* PSInstance::MainThreadThunk(void *info) {
+  s_InstanceObject->Log("Got MainThreadThunk.\n");
+  StartInfo* si = static_cast<StartInfo*>(info);
+  si->inst_->main_loop_ = new pp::MessageLoop(si->inst_);
+  si->inst_->main_loop_->AttachToCurrentThread();
+
+  int ret = si->inst_->MainThread(si->argc_, si->argv_);
+  for (uint32_t i = 0; i < si->argc_; i++) {
+    delete[] si->argv_[i];
+  }
+  delete[] si->argv_;
+  delete si;
+
+  return NULL;
+}
+
+// The default implementation supports running a 'C' main.
+int PSInstance::MainThread(int argc, const char *argv[]) {
+  if (main_cb_) {
+    Log("Starting MAIN.\n");
+    int ret = main_cb_(argc, argv);
+    Log("Main thread returned with %d.\n", ret);
+    return ret;
+  }
+
+  Error("No main defined.\n");
+  return 0;
+}
+
+PSInstance::PSInstance(PP_Instance instance, const char *argv[])
+    : pp::Instance(instance),
+      main_loop_(NULL),
+      verbosity_(PSV_LOG),
+      events_enabled_(PSE_NONE) {
+  // Set the single Instance object
+  s_InstanceObject = this;
+
+#ifdef DEBUG
+  SetVerbosity(PSV_LOG);
+#endif
+
+  // Place PPAPI_MAIN_USE arguments into properties map
+  while (*argv) {
+    std::string key = *argv++;
+    std::string val = *argv++;
+    properties_[key] = val;
+  }
+
+  RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE |
+                     PP_INPUTEVENT_CLASS_KEYBOARD |
+                     PP_INPUTEVENT_CLASS_WHEEL |
+                     PP_INPUTEVENT_CLASS_TOUCH);
+
+  ppb_core_ = static_cast<const PPB_Core*>(
+      pp::Module::Get()->GetBrowserInterface(PPB_CORE_INTERFACE));
+
+  ppb_var_ = static_cast<const PPB_Var*>(
+      pp::Module::Get()->GetBrowserInterface(PPB_VAR_INTERFACE));
+
+  ppb_view_ = static_cast<const PPB_View*>(
+      pp::Module::Get()->GetBrowserInterface(PPB_VIEW_INTERFACE));
+}
+
+PSInstance::~PSInstance() {}
+
+void PSInstance::SetMain(PSMainFunc_t main) {
+  main_cb_ = main;
+}
+
+bool PSInstance::Init(uint32_t arg,
+                      const char* argn[],
+                      const char* argv[]) {
+  StartInfo* si = new StartInfo;
+
+  si->inst_ = this;
+  si->argc_ = 1;
+  si->argv_ = new const char *[arg*2+1];
+  si->argv_[0] = NULL;
+
+  // Process arguments passed into Module INIT from JavaScript
+  for (uint32_t i=0; i < arg; i++) {
+    if (argv[i]) {
+      Log("ARG %s=%s\n", argn[i], argv[i]);
+    } else {
+      Log("ARG %s\n", argn[i]);
+    }
+
+    // If we start with PM prefix set the instance argument map
+    if (0 == strncmp(argn[i], "ps_", 3)) {
+      std::string key = argn[i];
+      std::string val = argv[i];
+      properties_[key] = val;
+      continue;
+    }
+
+    // If this is the 'src' tag, then get the NMF name.
+    if (!strcmp("src", argn[i])) {
+      char *name = new char[strlen(argv[i]) + 1];
+      strcpy(name, argv[i]);
+      si->argv_[0] = name;
+    }
+    else {
+      // Otherwise turn it into arguments
+      char *key = new char[strlen(argn[i]) + 3];
+      key[0] = '-';
+      key[1] = '-';
+      strcpy(&key[2], argn[i]);
+
+      si->argv_[si->argc_++] = key;
+      if (argv[i] && argv[i][0]) {
+        char *val = new char[strlen(argv[i]) + 1];
+        strcpy(val, argv[i]);
+        si->argv_[si->argc_++] = val;
+      }
+    }
+  }
+
+  // If src was not found, set the first arg to something
+  if (NULL == si->argv_[0]) {
+    char *name = new char[5];
+    strcpy(name, "NMF?");
+    si->argv_[0] = name;
+  }
+
+  if (ProcessProperties()) {
+    pthread_t main_thread;
+    int ret = pthread_create(&main_thread, NULL, MainThreadThunk, si);
+    Log("Created thread: %d.\n", ret);
+    return ret == 0;
+  }
+
+  Log("Skipping create thread.\n");
+  return false;
+}
+
+const char* PSInstance::GetProperty(const char* key, const char* def) {
+  PropertyMap_t::iterator it = properties_.find(key);
+  if (it != properties_.end()) {
+    return it->second.c_str();
+  }
+  return def;
+}
+
+// Processes the properties passed fixed at compile time via the
+// initialization macro, or via dynamically set embed attributes
+// through instance DidCreate.
+bool PSInstance::ProcessProperties() {
+  // Get the default values
+  const char* stdin_path = GetProperty("ps_stdin", "/dev/stdin");
+  const char* stdout_path = GetProperty("ps_stdout", "/dev/stdout");
+  const char* stderr_path = GetProperty("ps_stderr", "/dev/console3");
+  const char* verbosity = GetProperty("ps_verbosity", NULL);
+
+  // Reset verbosity if passed in
+  if (verbosity) SetVerbosity(static_cast<Verbosity>(atoi(verbosity)));
+
+  // Enable NaCl IO to map STDIN, STDOUT, and STDERR
+  nacl_io_init_ppapi(PSGetInstanceId(), PSGetInterface);
+  int fd0 = open(stdin_path, O_RDONLY);
+  dup2(fd0, 0);
+
+  int fd1 = open(stdout_path, O_WRONLY);
+  dup2(fd1, 1);
+
+  int fd2 = open(stderr_path, O_WRONLY);
+  dup2(fd2, 2);
+
+  // Set line buffering on stdout and stderr
+  setvbuf(stderr, NULL, _IOLBF, 0);
+  setvbuf(stdout, NULL, _IOLBF, 0);
+  return true;
+}
+
+void PSInstance::SetVerbosity(Verbosity verbosity) {
+  verbosity_ = verbosity;
+}
+
+void PSInstance::Log(const char *fmt, ...) {
+  if (verbosity_ >= PSV_LOG) {
+    va_list ap;
+    va_start(ap, fmt);
+    vfprintf(stdout, fmt, ap);
+  }
+}
+
+void PSInstance::Warn(const char *fmt, ...) {
+  if (verbosity_ >= PSV_WARN) {
+    va_list ap;
+    va_start(ap, fmt);
+    vfprintf(stdout, fmt, ap);
+  }
+}
+
+void PSInstance::Error(const char *fmt, ...) {
+  if (verbosity_ >= PSV_ERROR) {
+    va_list ap;
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+  }
+}
+
+void PSInstance::SetEnabledEvents(uint32_t mask) {
+  events_enabled_ = mask;
+}
+
+void PSInstance::PostEvent(PSEventType type) {
+  assert(PSE_GRAPHICS3D_GRAPHICS3DCONTEXTLOST == type ||
+         PSE_MOUSELOCK_MOUSELOCKLOST == type);
+
+  if (events_enabled_ & type) {
+    PSEvent *env = (PSEvent *) malloc(sizeof(PSEvent));
+    memset(env, 0, sizeof(*env));
+    env->type = type;
+    event_queue_.Enqueue(env);
+  }
+}
+
+void PSInstance::PostEvent(PSEventType type, PP_Bool bool_value) {
+  assert(PSE_INSTANCE_DIDCHANGEFOCUS == type);
+
+  if (events_enabled_ & type) {
+    PSEvent *env = (PSEvent *) malloc(sizeof(PSEvent));
+    memset(env, 0, sizeof(*env));
+    env->type = type;
+    env->as_bool = bool_value;
+    event_queue_.Enqueue(env);
+  }
+}
+
+void PSInstance::PostEvent(PSEventType type, PP_Resource resource) {
+  assert(PSE_INSTANCE_HANDLEINPUT == type ||
+         PSE_INSTANCE_DIDCHANGEVIEW == type);
+
+  if (events_enabled_ & type) {
+    if (resource) {
+      ppb_core_->AddRefResource(resource);
+    }
+    PSEvent *env = (PSEvent *) malloc(sizeof(PSEvent));
+    memset(env, 0, sizeof(*env));
+    env->type = type;
+    env->as_resource = resource;
+    event_queue_.Enqueue(env);
+  }
+}
+
+void PSInstance::PostEvent(PSEventType type, const PP_Var& var) {
+  assert(PSE_INSTANCE_HANDLEMESSAGE == type);
+
+  if (events_enabled_ & type) {
+    ppb_var_->AddRef(var);
+    PSEvent *env = (PSEvent *) malloc(sizeof(PSEvent));
+    memset(env, 0, sizeof(*env));
+    env->type = type;
+    env->as_var = var;
+    event_queue_.Enqueue(env);
+  }
+}
+
+PSEvent* PSInstance::TryAcquireEvent() {
+  return event_queue_.Dequeue(false);
+}
+
+PSEvent* PSInstance::WaitAcquireEvent() {
+  return event_queue_.Dequeue(true);
+}
+
+void PSInstance::ReleaseEvent(PSEvent* event) {
+  if (event) {
+    switch(event->type) {
+      case PSE_INSTANCE_HANDLEMESSAGE:
+        ppb_var_->Release(event->as_var);
+        break;
+      case PSE_INSTANCE_HANDLEINPUT:
+      case PSE_INSTANCE_DIDCHANGEVIEW:
+        if (event->as_resource) {
+          ppb_core_->ReleaseResource(event->as_resource);
+        }
+        break;
+      default:
+        break;
+    }
+    free(event);
+  }
+}
+
+void PSInstance::HandleMessage(const pp::Var& message) {
+  Log("Got Message\n");
+  PostEvent(PSE_INSTANCE_HANDLEMESSAGE, message.pp_var());
+}
+
+bool PSInstance::HandleInputEvent(const pp::InputEvent& event) {
+  Log("Got Input\n");
+  PostEvent(PSE_INSTANCE_HANDLEINPUT, event.pp_resource());
+  return true;
+}
+
+void PSInstance::DidChangeView(const pp::View& view) {
+  pp::Size new_size = view.GetRect().size();
+  Log("Got View change: %d,%d\n", new_size.width(), new_size.height());
+  PostEvent(PSE_INSTANCE_DIDCHANGEVIEW, view.pp_resource());
+}
+
+void PSInstance::DidChangeFocus(bool focus) {
+  Log("Got Focus change: %s\n", focus ? "FOCUS ON" : "FOCUS OFF");
+  PostEvent(PSE_INSTANCE_DIDCHANGEFOCUS, focus ? PP_TRUE : PP_FALSE);
+}
+
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps_instance.h b/native_client_sdk/src/libraries/ppapi_simple/ps_instance.h
new file mode 100644
index 0000000000..d888dd7044
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps_instance.h
@@ -0,0 +1,121 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PPAPI_SIMPLE_PS_INSTANCE_H_
+#define PPAPI_SIMPLE_PS_INSTANCE_H_
+
+#include <map>
+
+#include "ppapi/c/pp_instance.h"
+#include "ppapi/c/pp_stdint.h"
+#include "ppapi/c/ppb_core.h"
+#include "ppapi/c/ppb_var.h"
+#include "ppapi/c/ppb_view.h"
+
+#include "ppapi/cpp/fullscreen.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/message_loop.h"
+#include "ppapi/cpp/mouse_lock.h"
+
+#include "ppapi/utility/completion_callback_factory.h"
+
+#include "ppapi_simple/ps_event.h"
+#include "ppapi_simple/ps_main.h"
+
+#include "sdk_util/thread_safe_queue.h"
+
+
+typedef std::map<std::string, std::string> PropertyMap_t;
+
+class PSInstance : public pp::Instance {
+ public:
+  enum Verbosity {
+    PSV_SILENT,
+    PSV_ERROR,
+    PSV_WARN,
+    PSV_LOG,
+  };
+
+  // Returns a pointer to the global instance
+  static PSInstance* GetInstance();
+
+  PSInstance(PP_Instance inst, const char *argv[]);
+  virtual ~PSInstance();
+
+  // Set a function which will be called on a new thread once initialized.
+  // NOTE:  This must be called by the Factory, once Init is called, this
+  // function will have no effect.
+  void SetMain(PSMainFunc_t func);
+
+  // Returns value based on KEY or default.
+  const char* GetProperty(const char* key, const char* def = NULL);
+
+  // Started on Init, a thread which can be safely blocked.
+  virtual int MainThread(int argc, const char* argv[]);
+
+  // Logging Functions
+  void SetVerbosity(Verbosity verbosity);
+  void Log(const char *fmt, ...);
+  void Warn(const char *fmt, ...);
+  void Error(const char *fmt, ...);
+
+  // Event Functions
+  void SetEnabledEvents(uint32_t mask);
+  void PostEvent(PSEventType type);
+  void PostEvent(PSEventType type, PP_Bool bool_value);
+  void PostEvent(PSEventType type, PP_Resource resource);
+  void PostEvent(PSEventType type, const PP_Var& var);
+
+  PSEvent* TryAcquireEvent();
+  PSEvent* WaitAcquireEvent();
+  void ReleaseEvent(PSEvent* event);
+
+ protected:
+  // Callback functions triggered by Pepper
+  //
+  // These functions are called on the main pepper thread, so they must
+  // not block.
+  //
+  // Called by the browser when the NaCl module is loaded and all ready to go.
+  // This function will create a new thread which will run the pseudo main.
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]);
+
+  // Called whenever the in-browser window changes size, it will pass a
+  // context change request to whichever thread is handling rendering.
+  virtual void DidChangeView(const pp::View& view);
+
+  // Called by the browser when the NaCl canvas gets or loses focus.
+  virtual void DidChangeFocus(bool has_focus);
+
+  // Called by the browser to handle the postMessage() call in Javascript.
+  virtual void HandleMessage(const pp::Var& message);
+
+  // Called by the browser to handle incoming input events.  Events are Q'd
+  // and can later be processed on a sperate processing thread.
+  virtual bool HandleInputEvent(const pp::InputEvent& event);
+
+  // Called by Init to processes default and embed tag arguments prior to
+  // launching the 'ppapi_main' thread.
+  virtual bool ProcessProperties();
+
+ private:
+  static void* MainThreadThunk(void *start_info);
+
+ protected:
+  pp::MessageLoop* main_loop_;
+
+  PropertyMap_t properties_;
+  ThreadSafeQueue<PSEvent> event_queue_;
+  uint32_t events_enabled_;
+  Verbosity verbosity_;
+
+  PSMainFunc_t main_cb_;
+
+  const PPB_Core* ppb_core_;
+  const PPB_Var* ppb_var_;
+  const PPB_View* ppb_view_;
+};
+
+#endif  // PPAPI_MAIN_PS_INSTANCE_H_
+
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps_main.cc b/native_client_sdk/src/libraries/ppapi_simple/ps_main.cc
new file mode 100644
index 0000000000..302aeaf44b
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps_main.cc
@@ -0,0 +1,17 @@
+/* Copyright (c) 2012 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "ppapi/c/pp_instance.h"
+#include "ppapi/c/pp_module.h"
+
+#include "ppapi_simple/ps_instance.h"
+#include "ppapi_simple/ps_main.h"
+
+
+void* PSMainCreate(PP_Instance inst, PSMainFunc_t func, const char* argv[]) {
+  PSInstance* pInst = new PSInstance(inst, argv);
+  pInst->SetMain(func);
+  return pInst;
+}
diff --git a/native_client_sdk/src/libraries/ppapi_simple/ps_main.h b/native_client_sdk/src/libraries/ppapi_simple/ps_main.h
new file mode 100644
index 0000000000..6bd66e291a
--- /dev/null
+++ b/native_client_sdk/src/libraries/ppapi_simple/ps_main.h
@@ -0,0 +1,38 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PPAPI_SIMPLE_PS_MAIN_H_
+#define PPAPI_SIMPLE_PS_MAIN_H_
+
+#include "ppapi_simple/ps.h"
+#include "ppapi_simple/ps_event.h"
+
+EXTERN_C_BEGIN
+
+typedef int (*PSMainFunc_t)(int argc, const char *argv[]);
+
+/**
+ * PSMainCreate
+ *
+ * Constructs an instance SimpleInstance and configures it to call into
+ * the provided "main" function.
+ */
+void* PSMainCreate(PP_Instance inst, PSMainFunc_t func, const char **argv);
+
+
+/**
+ * PPAPI_SIMPLE_REGISTER_MAIN
+ *
+ * Constructs a PSInstance ojbect and configures it to use call the provided
+ * 'main' function on it's own thread once initialization is complete.
+ */
+
+
+#define PPAPI_SIMPLE_REGISTER_MAIN(main, ...)             \
+  PPAPI_SIMPLE_USE_MAIN(PSMainCreate, main, ##__VA_ARGS__)
+
+EXTERN_C_END
+
+#endif  /* PPAPI_SIMPLE_PPAPI_SIMPLE_MAIN_H_ */
+
diff --git a/native_client_sdk/src/libraries/utils/auto_lock.h b/native_client_sdk/src/libraries/sdk_util/auto_lock.h
index 19dd66f84d..88215d0cb3 100644
--- a/native_client_sdk/src/libraries/utils/auto_lock.h
+++ b/native_client_sdk/src/libraries/sdk_util/auto_lock.h
@@ -3,8 +3,8 @@
  * found in the LICENSE file.
  */
 
-#ifndef LIBRARIES_UTILS_AUTO_LOCK_H_
-#define LIBRARIES_UTILS_AUTO_LOCK_H_
+#ifndef LIBRARIES_SDK_UTIL_AUTO_LOCK_H_
+#define LIBRARIES_SDK_UTIL_AUTO_LOCK_H_
 
 #include <pthread.h>
 
@@ -27,4 +27,5 @@ class AutoLock {
   pthread_mutex_t* lock_;
 };
 
-#endif  // LIBRARIES_UTILS_AUTO_LOCK_H_
+#endif  // LIBRARIES_SDK_UTIL_AUTO_LOCK_H_
+
diff --git a/native_client_sdk/src/libraries/sdk_util/library.dsc b/native_client_sdk/src/libraries/sdk_util/library.dsc
new file mode 100644
index 0000000000..0491d980ea
--- /dev/null
+++ b/native_client_sdk/src/libraries/sdk_util/library.dsc
@@ -0,0 +1,29 @@
+{
+  'TOOLS': ['newlib', 'glibc', 'pnacl', 'win'],
+  'SEARCH': [
+    '.'
+  ],
+  'TARGETS': [
+    {
+      'NAME' : 'sdk_util',
+      'TYPE' : 'lib',
+      'SOURCES' : [
+        'thread_pool.cc'
+      ]
+    }
+  ],
+  'HEADERS': [
+    {
+      'FILES': [
+        'auto_lock.h',
+        'macros.h',
+        'ref_object.h',
+        'thread_pool.h',
+        'thread_safe_queue.h'
+      ],
+      'DEST': 'include/sdk_util',
+    }
+  ],
+  'DEST': 'src',
+  'NAME': 'sdk_util',
+}
diff --git a/native_client_sdk/src/libraries/utils/macros.h b/native_client_sdk/src/libraries/sdk_util/macros.h
index 718d83fce9..fd15dc38c8 100644
--- a/native_client_sdk/src/libraries/utils/macros.h
+++ b/native_client_sdk/src/libraries/sdk_util/macros.h
@@ -2,8 +2,8 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-#ifndef LIBRARIES_UTILS_MACROS_H_
-#define LIBRARIES_UTILS_MACROS_H_
+#ifndef LIBRARIES_SDK_UTIL_MACROS_H_
+#define LIBRARIES_SDK_UTIL_MACROS_H_
 
 /**
  * A macro to disallow the evil copy constructor and operator= functions
@@ -46,4 +46,5 @@
     force_link_##x = 1; \
   }
 
-#endif  /* LIBRARIES_UTILS_MACROS_H_ */
+#endif  /* LIBRARIES_SDK_UTIL_MACROS_H_ */
+
diff --git a/native_client_sdk/src/libraries/utils/ref_object.h b/native_client_sdk/src/libraries/sdk_util/ref_object.h
index d3eb9f87c4..4e81f32df6 100644
--- a/native_client_sdk/src/libraries/utils/ref_object.h
+++ b/native_client_sdk/src/libraries/sdk_util/ref_object.h
@@ -3,8 +3,8 @@
  * found in the LICENSE file.
  */
 
-#ifndef LIBRARIES_UTILS_REF_OBJECT
-#define LIBRARIES_UTILS_REF_OBJECT
+#ifndef LIBRARIES_SDK_UTIL_REF_OBJECT
+#define LIBRARIES_SDK_UTIL_REF_OBJECT
 
 #include <stdlib.h>
 #include "pthread.h"
@@ -45,4 +45,5 @@ class RefObject {
   int ref_count_;
 };
 
-#endif  // LIBRARIES_UTILS_REF_OBJECT
+#endif  // LIBRARIES_SDK_UTIL_REF_OBJECT
+
diff --git a/native_client_sdk/src/libraries/sdk_util/thread_pool.cc b/native_client_sdk/src/libraries/sdk_util/thread_pool.cc
new file mode 100644
index 0000000000..e7d2e5cb6b
--- /dev/null
+++ b/native_client_sdk/src/libraries/sdk_util/thread_pool.cc
@@ -0,0 +1,144 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sdk_util/thread_pool.h"
+
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sdk_util/auto_lock.h"
+
+// Initializes mutex, semaphores and a pool of threads.  If 0 is passed for
+// num_threads, all work will be performed on the dispatch thread.
+ThreadPool::ThreadPool(int num_threads)
+    : threads_(NULL), counter_(0), num_threads_(num_threads), exiting_(false),
+      user_data_(NULL), user_work_function_(NULL) {
+  if (num_threads_ > 0) {
+    int status;
+    status = sem_init(&work_sem_, 0, 0);
+    if (-1 == status) {
+      fprintf(stderr, "Failed to initialize semaphore!\n");
+      exit(-1);
+    }
+    status = sem_init(&done_sem_, 0, 0);
+    if (-1 == status) {
+      fprintf(stderr, "Failed to initialize semaphore!\n");
+      exit(-1);
+    }
+    threads_ = new pthread_t[num_threads_];
+    for (int i = 0; i < num_threads_; i++) {
+      status = pthread_create(&threads_[i], NULL, WorkerThreadEntry, this);
+      if (0 != status) {
+        fprintf(stderr, "Failed to create thread!\n");
+        exit(-1);
+      }
+    }
+  }
+}
+
+// Post exit request, wait for all threads to join, and cleanup.
+ThreadPool::~ThreadPool() {
+  if (num_threads_ > 0) {
+    PostExitAndJoinAll();
+    delete[] threads_;
+    sem_destroy(&done_sem_);
+    sem_destroy(&work_sem_);
+  }
+}
+
+// Setup work parameters.  This function is called from the dispatch thread,
+// when all worker threads are sleeping.
+void ThreadPool::Setup(int counter, WorkFunction work, void *data) {
+  counter_ = counter;
+  user_work_function_ = work;
+  user_data_ = data;
+}
+
+// Return decremented task counter.  This function
+// can be called from multiple threads at any given time.
+int ThreadPool::DecCounter() {
+#if defined(__native_client__)
+  // Use fast atomic sub & fetch.
+  return __sync_sub_and_fetch(&counter_, 1);
+#else
+  // Fallback to a more platform independent pthread mutex via AutoLock.
+  static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+  AutoLock lock(&mutex);
+  return --counter_;
+#endif
+}
+
+// Set exit flag, post and join all the threads in the pool.  This function is
+// called only from the dispatch thread, and only when all worker threads are
+// sleeping.
+void ThreadPool::PostExitAndJoinAll() {
+  exiting_ = true;
+  // Wake up all the sleeping worker threads.
+  for (int i = 0; i < num_threads_; ++i)
+    sem_post(&work_sem_);
+  void* retval;
+  for (int i = 0; i < num_threads_; ++i)
+    pthread_join(threads_[i], &retval);
+}
+
+// Main work loop - one for each worker thread.
+void ThreadPool::WorkLoop() {
+  while (true) {
+    // Wait for work. If no work is availble, this thread will sleep here.
+    sem_wait(&work_sem_);
+    if (exiting_) break;
+    while (true) {
+      // Grab a task index to work on from the counter.
+      int task_index = DecCounter();
+      if (task_index < 0)
+        break;
+      user_work_function_(task_index, user_data_);
+    }
+    // Post to dispatch thread work is done.
+    sem_post(&done_sem_);
+  }
+}
+
+// pthread entry point for a worker thread.
+void* ThreadPool::WorkerThreadEntry(void* thiz) {
+  static_cast<ThreadPool*>(thiz)->WorkLoop();
+  return NULL;
+}
+
+// DispatchMany() will dispatch a set of tasks across worker threads.
+// Note: This function will block until all work has completed.
+void ThreadPool::DispatchMany(int num_tasks, WorkFunction work, void* data) {
+  // On entry, all worker threads are sleeping.
+  Setup(num_tasks, work, data);
+
+  // Wake up the worker threads & have them process tasks.
+  for (int i = 0; i < num_threads_; i++)
+    sem_post(&work_sem_);
+
+  // Worker threads are now awake and busy.
+
+  // This dispatch thread will now sleep-wait for the worker threads to finish.
+  for (int i = 0; i < num_threads_; i++)
+    sem_wait(&done_sem_);
+  // On exit, all tasks are done and all worker threads are sleeping again.
+}
+
+//  DispatchHere will dispatch all tasks on this thread.
+void ThreadPool::DispatchHere(int num_tasks, WorkFunction work, void* data) {
+  for (int i = 0; i < num_tasks; i++)
+    work(i, data);
+}
+
+// Dispatch() will invoke the user supplied work function across
+// one or more threads for each task.
+// Note: This function will block until all work has completed.
+void ThreadPool::Dispatch(int num_tasks, WorkFunction work, void* data) {
+  if (num_threads_ > 0)
+    DispatchMany(num_tasks, work, data);
+  else
+    DispatchHere(num_tasks, work, data);
+}
+
diff --git a/native_client_sdk/src/libraries/sdk_util/thread_pool.h b/native_client_sdk/src/libraries/sdk_util/thread_pool.h
new file mode 100644
index 0000000000..760b3f715d
--- /dev/null
+++ b/native_client_sdk/src/libraries/sdk_util/thread_pool.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Simple thread pool class
+
+#ifndef LIBRARIES_SDK_UTIL_THREAD_POOL_H_
+#define LIBRARIES_SDK_UTIL_THREAD_POOL_H_
+
+#include <pthread.h>
+#include <semaphore.h>
+
+// typdef helper for work function
+typedef void (*WorkFunction)(int task_index, void* data);
+
+// ThreadPool is a class to manage num_threads and assign
+// them num_tasks of work at a time. Each call
+// to Dispatch(..) will block until all tasks complete.
+// If 0 is passed in for num_threads, all tasks will be
+// issued on the dispatch thread.
+
+class ThreadPool {
+ public:
+  void Dispatch(int num_tasks, WorkFunction work, void* data);
+  explicit ThreadPool(int num_threads);
+  ~ThreadPool();
+ private:
+  int DecCounter();
+  void Setup(int counter, WorkFunction work, void* data);
+  void DispatchMany(int num_tasks, WorkFunction work, void* data);
+  void DispatchHere(int num_tasks, WorkFunction work, void* data);
+  void WorkLoop();
+  static void* WorkerThreadEntry(void* data);
+  void PostExitAndJoinAll();
+  pthread_t* threads_;
+  int counter_;
+  const int num_threads_;
+  bool exiting_;
+  void* user_data_;
+  WorkFunction user_work_function_;
+  sem_t work_sem_;
+  sem_t done_sem_;
+};
+#endif  // LIBRARIES_SDK_UTIL_THREAD_POOL_H_
+
diff --git a/native_client_sdk/src/libraries/sdk_util/thread_safe_queue.h b/native_client_sdk/src/libraries/sdk_util/thread_safe_queue.h
new file mode 100644
index 0000000000..545b7c4589
--- /dev/null
+++ b/native_client_sdk/src/libraries/sdk_util/thread_safe_queue.h
@@ -0,0 +1,63 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef LIBRARIES_SDK_UTIL_THREAD_SAFE_QUEUE_H_
+#define LIBRARIES_SDK_UTIL_THREAD_SAFE_QUEUE_H_
+
+#include <pthread.h>
+
+#include <list>
+
+#include "sdk_util/auto_lock.h"
+#include "sdk_util/macros.h"
+
+
+// ThreadSafeQueue
+//
+// A simple template to support multithreaded and optionally blocking access
+// to a Queue of object pointers.
+//
+template<class T> class ThreadSafeQueue {
+ public:
+  ThreadSafeQueue() {
+    pthread_mutex_init(&mutex_, NULL);
+    pthread_cond_init(&cond_, NULL);
+  }
+
+  ~ThreadSafeQueue() {
+    pthread_mutex_destroy(&mutex_);
+    pthread_cond_destroy(&cond_);
+  }
+
+  void Enqueue(T* item) {
+    AutoLock lock(&mutex_);
+    list_.push_back(item);
+
+    pthread_cond_signal(&cond_);
+  }
+
+  T* Dequeue(bool block) {
+    AutoLock lock(&mutex_);
+
+    // If blocking enabled, wait until we queue is non-empty
+    if (block) {
+      while (list_.empty()) pthread_cond_wait(&cond_, &mutex_);
+    }
+
+    if (list_.empty()) return NULL;
+
+    T* item = list_.front();
+    list_.pop_front();
+    return item;
+  }
+
+ private:
+  std::list<T*> list_;
+  pthread_cond_t  cond_;
+  pthread_mutex_t mutex_;
+  DISALLOW_COPY_AND_ASSIGN(ThreadSafeQueue);
+};
+
+#endif  // LIBRARIES_SDK_UTIL_THREAD_SAFE_QUEUE_H_
+
diff --git a/native_client_sdk/src/tools/create_nmf.py b/native_client_sdk/src/tools/create_nmf.py
index 5cf2e1472d..a9aad544cb 100755
--- a/native_client_sdk/src/tools/create_nmf.py
+++ b/native_client_sdk/src/tools/create_nmf.py
@@ -610,10 +610,16 @@ def GetDefaultLibPath(config):
 
   osname = getos.GetPlatform()
   libpath = [
+    # Core toolchain libraries
     'toolchain/%s_x86_glibc/x86_64-nacl/lib' % osname,
     'toolchain/%s_x86_glibc/x86_64-nacl/lib32' % osname,
+    # naclports installed libraries
+    'toolchain/%s_x86_glibc/x86_64-nacl/usr/lib' % osname,
+    'toolchain/%s_x86_glibc/i686-nacl/usr/lib' % osname,
+    # SDK bundle libraries
     'lib/glibc_x86_32/%s' % config,
     'lib/glibc_x86_64/%s' % config,
+    # naclports bundle libraries
     'ports/lib/glibc_x86_32/%s' % config,
     'ports/lib/glibc_x86_64/%s' % config,
   ]
@@ -666,10 +672,10 @@ def main(argv):
     DebugPrint.debug_mode = True
 
   if options.toolchain is not None:
-    print 'warning: option -t/--toolchain is deprecated.'
+    sys.stderr.write('warning: option -t/--toolchain is deprecated.\n')
 
   if len(args) < 1:
-    raise Error('No nexe files specified.  See --help for more info')
+    parser.error('No nexe files specified.  See --help for more info')
 
   canonicalized = ParseExtraFiles(options.extra_files, sys.stderr)
   if canonicalized is None:
@@ -679,7 +685,7 @@ def main(argv):
   for ren in options.name:
     parts = ren.split(',')
     if len(parts) != 2:
-      raise Error('Expecting --name=<orig_arch.so>,<new_name.so>')
+      parser.error('Expecting --name=<orig_arch.so>,<new_name.so>')
     remap[parts[0]] = parts[1]
 
   if options.path_prefix:
@@ -689,9 +695,9 @@ def main(argv):
 
   for libpath in options.lib_path:
     if not os.path.exists(libpath):
-      raise Error('Specified library path does not exist: %s' % libpath)
-    if not os.path.isdir(libpath):
-      raise Error('Specified library is not a directory: %s' % libpath)
+      sys.stderr.write('Specified library path does not exist: %s\n' % libpath)
+    elif not os.path.isdir(libpath):
+      sys.stderr.write('Specified library is not a directory: %s\n' % libpath)
 
   if not options.no_default_libpath:
     # Add default libraries paths to the end of the search path.
diff --git a/native_client_sdk/src/tools/host_vc.mk b/native_client_sdk/src/tools/host_vc.mk
index 945fee3892..d41629b22d 100644
--- a/native_client_sdk/src/tools/host_vc.mk
+++ b/native_client_sdk/src/tools/host_vc.mk
@@ -27,13 +27,13 @@ $(error Unable to find cl.exe in PATH while building Windows host build)
 endif
 
 
-ifeq ('Debug','$(CONFIG)')
-WIN_OPT_FLAGS ?= /Od /MTd /Z7 -D NACL_SDK_DEBUG
-else
+ifeq ($(CONFIG),Release)
 WIN_OPT_FLAGS ?= /O2 /MT /Z7
+else
+WIN_OPT_FLAGS ?= /Od /MTd /Z7 -DNACL_SDK_DEBUG
 endif
 
-WIN_FLAGS ?= -D WIN32 -D _WIN32 -D PTW32_STATIC_LIB
+WIN_FLAGS ?= -DWIN32 -D_WIN32 -DPTW32_STATIC_LIB
 
 
 #
diff --git a/native_client_sdk/src/tools/nacl_gcc.mk b/native_client_sdk/src/tools/nacl_gcc.mk
index 1460637e20..a68d230fde 100644
--- a/native_client_sdk/src/tools/nacl_gcc.mk
+++ b/native_client_sdk/src/tools/nacl_gcc.mk
@@ -47,13 +47,14 @@ ARM_NM ?= $(TC_PATH)/$(OSNAME)_arm_$(TOOLCHAIN)/bin/arm-nacl-nm
 
 
 # Architecture-specific flags
-X86_32_CFLAGS ?= -DNACL_ARCH=x86_32
-X86_64_CFLAGS ?= -DNACL_ARCH=x86_64
-ARM_CFLAGS ?= -DNACL_ARCH=arm
+X86_32_CFLAGS ?=
+X86_64_CFLAGS ?=
+ARM_CFLAGS ?=
+
+X86_32_CXXFLAGS ?=
+X86_64_CXXFLAGS ?=
+ARM_CXXFLAGS ?=
 
-X86_32_CXXFLAGS ?= -DNACL_ARCH=x86_32
-X86_64_CXXFLAGS ?= -DNACL_ARCH=x86_64
-ARM_CXXFLAGS ?= -DNACL_ARCH=arm
 
 #
 # Compile Macro