lddtree: Move ELF files to its own subdir.

This patch adds a new --elf-subdir flag that makes the wrapper-script
move the original ELF to the passed subdirectory instead of appending
a .elf suffix.

Appending .elf works in general, except for multicall binaries that
use argv[0] to determine what program was called.

BUG=chromium:526753
TEST=`./build_library/generate_au_zip.py` with the new flags places files in .elf/;

Change-Id: Iee7c4b727e8de54919f396812d3e8b061f4091ad
Reviewed-on: https://chromium-review.googlesource.com/296424
Commit-Ready: Alex Deymo <deymo@chromium.org>
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>

1 files changed, 24 insertions, 5 deletions

diff --git a/third_party/lddtree.py b/third_party/lddtree.py
index 27924799f..9fffcbaa9 100644
--- a/third_party/lddtree.py
+++ b/third_party/lddtree.py
@@ -101,7 +101,7 @@ def dedupe(items):
   return [seen.setdefault(x, x) for x in items if x not in seen]
 
 
-def GenerateLdsoWrapper(root, path, interp, libpaths=()):
+def GenerateLdsoWrapper(root, path, interp, libpaths=(), elfsubdir=None):
   """Generate a shell script wrapper which uses local ldso to run the ELF
 
   Since we cannot rely on the host glibc (or other libraries), we need to
@@ -113,6 +113,9 @@ def GenerateLdsoWrapper(root, path, interp, libpaths=()):
     path: The full path (inside |root|) to the program to wrap
     interp: The ldso interpreter that we need to execute
     libpaths: Extra lib paths to search for libraries
+    elfsubdir: The sub-directory where the original ELF file lives. If not
+               provided, a '.elf' suffix will be added to the original file
+               instead.
   """
   basedir = os.path.dirname(path)
   interp_dir, interp_name = os.path.split(interp)
@@ -123,6 +126,18 @@ def GenerateLdsoWrapper(root, path, interp, libpaths=()):
     'libpaths': ':'.join(['${basedir}/' + os.path.relpath(p, basedir)
                           for p in libpaths]),
   }
+
+  wrappath = root + path
+  if elfsubdir:
+    elf_wrap_dir = os.path.join(os.path.dirname(wrappath), elfsubdir)
+    makedirs(elf_wrap_dir)
+    elf_wrappath = os.path.join(elf_wrap_dir, os.path.basename(wrappath))
+    replacements['elf_path'] = '${basedir}/%s/%s' % (elfsubdir,
+                                                     os.path.basename(wrappath))
+  else:
+    elf_wrappath = wrappath + '.elf'
+    replacements['elf_path'] = '${base}.elf'
+
   wrapper = """#!/bin/sh
 if ! base=$(realpath "$0" 2>/dev/null); then
   case $0 in
@@ -135,11 +150,10 @@ exec \
   "${basedir}/%(interp)s" \
   --library-path "%(libpaths)s" \
   --inhibit-rpath '' \
-  "${base}.elf" \
+  "%(elf_path)s" \
   "$@"
 """
-  wrappath = root + path
-  os.rename(wrappath, wrappath + '.elf')
+  os.rename(wrappath, elf_wrappath)
   with open(wrappath, 'w') as f:
     f.write(wrapper % replacements)
   os.chmod(wrappath, 0o0755)
@@ -540,7 +554,8 @@ def _ActionCopy(options, elf):
         interp = os.path.join(options.libdir, os.path.basename(elf['interp']))
       else:
         interp = _StripRoot(elf['interp'])
-      GenerateLdsoWrapper(options.dest, subdst, interp, libpaths)
+      GenerateLdsoWrapper(options.dest, subdst, interp, libpaths,
+                          options.elf_subdir)
 
   # XXX: We should automatically import libgcc_s.so whenever libpthread.so
   # is copied over (since we know it can be dlopen-ed by NPTL at runtime).
@@ -651,6 +666,10 @@ they need will be placed into /foo/lib/ only.""")
   group.add_option('--generate-wrappers',
     action='store_true', default=False,
     help='Wrap executable ELFs with scripts for local ldso')
+  group.add_option('--elf-subdir',
+    default=None, type='string',
+    help='When wrapping executable ELFs, place the original file in this '
+         'sub-directory. By default, it appends a .elf suffix instead.')
   group.add_option('--copy-non-elfs',
     action='store_true', default=False,
     help='Copy over plain (non-ELF) files instead of warn+ignore')