adb: win32: initial IPv6 support and improved Winsock error reporting

Call getaddrinfo() for connecting to IPv6 destinations.

Winsock APIs do not set errno. WSAGetLastError() returns Winsock errors
that are more numerous than BSD sockets, so it really doesn't make sense
to map those to BSD socket errors. Plus, even if we did that, the
Windows C Runtime (that mingw binaries use) has a strerror() that does
not recognize BSD socket error codes.

The solution is to wrap the various libcutils socket_* APIs with
sysdeps.h network_* APIs. For POSIX, the network_* APIs just call
strerror(). For Windows, they call SystemErrorCodeToString() (adapted
from Chromium).

Also in this change:

 - Various other code was modified to return errors in a std::string*
   argument, to be able to surface the error string to the end-user.

 - Improved error checking and use of D() to log Winsock errors for
   improved debuggability.

 - For sysdeps_win32.cpp, added unique_fh class that works like
   std::unique_ptr, for calling _fh_close().

 - Fix win32 adb_socketpair() setting of errno in error case.

 - Improve _socket_set_errno() D() logging to reduce confusion. Map
   a few extra error codes.

 - Move adb_shutdown() lower in sysdeps_win32.cpp so it can call
   _socket_set_errno().

 - Move network_connect() from adb_utils.cpp to sysdeps.h.

 - Merge socket_loopback_server() and socket_inaddr_any_server() into
   _network_server() since most of the code was identical.

Change-Id: I945f36870f320578b3a11ba093852ba6f7b93400
Signed-off-by: Spencer Low <CompareAndSwap@gmail.com>

13 files changed, 366 insertions, 195 deletions

diff --git a/adb.cpp b/adb.cpp
index aa9ef55..aa0256d 100644
--- a/adb.cpp
+++ b/adb.cpp
@@ -801,11 +801,13 @@ int handle_forward_request(const char* service, TransportType type, const char*
             return 1;
         }
 
+        std::string error;
         InstallStatus r;
         if (kill_forward) {
             r = remove_listener(pieces[0].c_str(), transport);
         } else {
-            r = install_listener(pieces[0], pieces[1].c_str(), transport, no_rebind);
+            r = install_listener(pieces[0], pieces[1].c_str(), transport,
+                                 no_rebind, &error);
         }
         if (r == INSTALL_STATUS_OK) {
 #if ADB_HOST
@@ -821,7 +823,8 @@ int handle_forward_request(const char* service, TransportType type, const char*
           case INSTALL_STATUS_OK: message = "success (!)"; break;
           case INSTALL_STATUS_INTERNAL_ERROR: message = "internal error"; break;
           case INSTALL_STATUS_CANNOT_BIND:
-            message = android::base::StringPrintf("cannot bind to socket: %s", strerror(errno));
+            message = android::base::StringPrintf("cannot bind to socket: %s",
+                                                  error.c_str());
             break;
           case INSTALL_STATUS_CANNOT_REBIND:
             message = android::base::StringPrintf("cannot rebind existing socket");
diff --git a/adb_client.cpp b/adb_client.cpp
index 418662c..6d75966 100644
--- a/adb_client.cpp
+++ b/adb_client.cpp
@@ -153,8 +153,8 @@ int _adb_connect(const std::string& service, std::string* error) {
     }
 
     int fd;
+    std::string reason;
     if (__adb_server_name) {
-        std::string reason;
         fd = network_connect(__adb_server_name, __adb_server_port, SOCK_STREAM, 0, &reason);
         if (fd == -1) {
             *error = android::base::StringPrintf("can't connect to %s:%d: %s",
@@ -163,9 +163,10 @@ int _adb_connect(const std::string& service, std::string* error) {
             return -2;
         }
     } else {
-        fd = socket_loopback_client(__adb_server_port, SOCK_STREAM);
+        fd = network_loopback_client(__adb_server_port, SOCK_STREAM, &reason);
         if (fd == -1) {
-            *error = perror_str("cannot connect to daemon");
+            *error = android::base::StringPrintf("cannot connect to daemon: %s",
+                                                 reason.c_str());
             return -2;
         }
     }
diff --git a/adb_listeners.cpp b/adb_listeners.cpp
index bb45022..1e7ce5d 100644
--- a/adb_listeners.cpp
+++ b/adb_listeners.cpp
@@ -110,27 +110,30 @@ static void listener_disconnect(void* listener, atransport* t) {
     free_listener(reinterpret_cast<alistener*>(listener));
 }
 
-static int local_name_to_fd(const char* name) {
+static int local_name_to_fd(const char* name, std::string* error) {
     if (!strncmp("tcp:", name, 4)) {
         int port = atoi(name + 4);
         if (gListenAll > 0) {
-            return socket_inaddr_any_server(port, SOCK_STREAM);
+            return network_inaddr_any_server(port, SOCK_STREAM, error);
         } else {
-            return socket_loopback_server(port, SOCK_STREAM);
+            return network_loopback_server(port, SOCK_STREAM, error);
         }
     }
 #if !defined(_WIN32)  // No Unix-domain sockets on Windows.
     // It's nonsensical to support the "reserved" space on the adb host side
     if (!strncmp(name, "local:", 6)) {
-        return socket_local_server(name + 6, ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM);
+        return network_local_server(name + 6,
+                ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM, error);
     } else if (!strncmp(name, "localabstract:", 14)) {
-        return socket_local_server(name + 14, ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM);
+        return network_local_server(name + 14,
+                ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM, error);
     } else if (!strncmp(name, "localfilesystem:", 16)) {
-        return socket_local_server(name + 16, ANDROID_SOCKET_NAMESPACE_FILESYSTEM, SOCK_STREAM);
+        return network_local_server(name + 16,
+                ANDROID_SOCKET_NAMESPACE_FILESYSTEM, SOCK_STREAM, error);
     }
 
 #endif
-    printf("unknown local portname '%s'\n", name);
+    *error = android::base::StringPrintf("unknown local portname '%s'", name);
     return -1;
 }
 
@@ -178,7 +181,8 @@ void remove_all_listeners(void)
 InstallStatus install_listener(const std::string& local_name,
                                   const char *connect_to,
                                   atransport* transport,
-                                  int no_rebind)
+                                  int no_rebind,
+                                  std::string* error)
 {
     for (alistener* l = listener_list.next; l != &listener_list; l = l->next) {
         if (local_name == l->local_name) {
@@ -226,9 +230,9 @@ InstallStatus install_listener(const std::string& local_name,
         goto nomem;
     }
 
-    listener->fd = local_name_to_fd(listener->local_name);
+    listener->fd = local_name_to_fd(listener->local_name, error);
     if (listener->fd < 0) {
-        printf("cannot bind '%s': %s\n", listener->local_name, strerror(errno));
+        printf("cannot bind '%s': %s\n", listener->local_name, error->c_str());
         free(listener->local_name);
         free(listener->connect_to);
         free(listener);
diff --git a/adb_listeners.h b/adb_listeners.h
index 67deb21..fa98eed 100644
--- a/adb_listeners.h
+++ b/adb_listeners.h
@@ -33,7 +33,8 @@ enum InstallStatus {
 InstallStatus install_listener(const std::string& local_name,
                                const char* connect_to,
                                atransport* transport,
-                               int no_rebind);
+                               int no_rebind,
+                               std::string* error);
 
 std::string format_listeners();
 
diff --git a/adb_utils.cpp b/adb_utils.cpp
index 3ba971d..12208cd 100644
--- a/adb_utils.cpp
+++ b/adb_utils.cpp
@@ -28,17 +28,10 @@
 #include <base/logging.h>
 #include <base/stringprintf.h>
 #include <base/strings.h>
-#include <cutils/sockets.h>
 
 #include "adb_trace.h"
 #include "sysdeps.h"
 
-#if defined(_WIN32)
-#include <ws2tcpip.h>
-#else
-#include <netdb.h>
-#endif
-
 bool getcwd(std::string* s) {
   char* cwd = getcwd(nullptr, 0);
   if (cwd != nullptr) *s = cwd;
@@ -178,18 +171,3 @@ bool parse_host_and_port(const std::string& address,
                << " (" << *canonical_address << ")";
     return true;
 }
-
-int network_connect(const std::string& host, int port, int type, int timeout, std::string* error) {
-    int getaddrinfo_error = 0;
-    int fd = socket_network_client_timeout(host.c_str(), port, type, timeout, &getaddrinfo_error);
-    if (fd != -1) {
-        return fd;
-    }
-    if (getaddrinfo_error != 0) {
-        // TODO: gai_strerror is not thread safe on Win32.
-        *error = gai_strerror(getaddrinfo_error);
-    } else {
-        *error = strerror(errno);
-    }
-    return -1;
-}
diff --git a/adb_utils.h b/adb_utils.h
index 30cd7a4..8c5208c 100644
--- a/adb_utils.h
+++ b/adb_utils.h
@@ -40,6 +40,4 @@ bool parse_host_and_port(const std::string& address,
                          std::string* host, int* port,
                          std::string* error);
 
-int network_connect(const std::string& host, int port, int type, int timeout, std::string* error);
-
 #endif
diff --git a/client/main.cpp b/client/main.cpp
index c018b8a..2b174cd 100644
--- a/client/main.cpp
+++ b/client/main.cpp
@@ -150,9 +150,10 @@ int adb_main(int is_daemon, int server_port) {
     local_init(DEFAULT_ADB_LOCAL_TRANSPORT_PORT);
     adb_auth_init();
 
+    std::string error;
     std::string local_name = android::base::StringPrintf("tcp:%d", server_port);
-    if (install_listener(local_name, "*smartsocket*", nullptr, 0)) {
-        LOG(FATAL) << "Could not install *smartsocket* listener";
+    if (install_listener(local_name, "*smartsocket*", nullptr, 0, &error)) {
+        LOG(FATAL) << "Could not install *smartsocket* listener: " << error;
     }
 
     if (is_daemon) {
diff --git a/console.cpp b/console.cpp
index b7f5345..ba5a72b 100644
--- a/console.cpp
+++ b/console.cpp
@@ -71,9 +71,11 @@ static int connect_to_console(const char* serial) {
         return -1;
     }
 
-    int fd = socket_loopback_client(port, SOCK_STREAM);
+    std::string error;
+    int fd = network_loopback_client(port, SOCK_STREAM, &error);
     if (fd == -1) {
-        fprintf(stderr, "error: could not connect to TCP port %d\n", port);
+        fprintf(stderr, "error: could not connect to TCP port %d: %s\n", port,
+                error.c_str());
         return -1;
     }
     return fd;
diff --git a/daemon/main.cpp b/daemon/main.cpp
index 157c97b..a63d67e 100644
--- a/daemon/main.cpp
+++ b/daemon/main.cpp
@@ -177,10 +177,13 @@ int adbd_main(int server_port) {
                 LOG(FATAL) << "Could not set selinux context";
             }
         }
+        std::string error;
         std::string local_name =
             android::base::StringPrintf("tcp:%d", server_port);
-        if (install_listener(local_name, "*smartsocket*", nullptr, 0)) {
-            LOG(FATAL) << "Could not install *smartsocket* listener";
+        if (install_listener(local_name, "*smartsocket*", nullptr, 0,
+                             &error)) {
+            LOG(FATAL) << "Could not install *smartsocket* listener: "
+                << error;
         }
     }
 
diff --git a/services.cpp b/services.cpp
index 708ef42..63a0a76 100644
--- a/services.cpp
+++ b/services.cpp
@@ -432,7 +432,8 @@ int service_to_fd(const char *name)
         int port = atoi(name + 4);
         name = strchr(name + 4, ':');
         if(name == 0) {
-            ret = socket_loopback_client(port, SOCK_STREAM);
+            std::string error;
+            ret = network_loopback_client(port, SOCK_STREAM, &error);
             if (ret >= 0)
                 disable_tcp_nagle(ret);
         } else {
diff --git a/sysdeps.h b/sysdeps.h
index c033999..a57f650 100644
--- a/sysdeps.h
+++ b/sysdeps.h
@@ -26,6 +26,8 @@
 
 #include <errno.h>
 
+#include <string>
+
 /*
  * TEMP_FAILURE_RETRY is defined by some, but not all, versions of
  * <unistd.h>. (Alas, it is not as standard as we'd hoped!) So, if it's
@@ -212,6 +214,12 @@ static __inline__ void  adb_sleep_ms( int  mseconds )
     Sleep( mseconds );
 }
 
+int network_loopback_client(int port, int type, std::string* error);
+int network_loopback_server(int port, int type, std::string* error);
+int network_inaddr_any_server(int port, int type, std::string* error);
+int network_connect(const std::string& host, int port, int type, int timeout,
+                    std::string* error);
+
 extern int  adb_socket_accept(int  serverfd, struct sockaddr*  addr, socklen_t  *addrlen);
 
 #undef   accept
@@ -240,10 +248,14 @@ static __inline__ int adb_is_absolute_host_path(const char* path) {
     return isalpha(path[0]) && path[1] == ':' && path[2] == '\\';
 }
 
+// Like strerror(), but for Win32 error codes.
+std::string SystemErrorCodeToString(DWORD error_code);
+
 #else /* !_WIN32 a.k.a. Unix */
 
 #include "fdevent.h"
 #include <cutils/misc.h>
+#include <cutils/sockets.h>
 #include <cutils/threads.h>
 #include <signal.h>
 #include <sys/wait.h>
@@ -254,6 +266,7 @@ static __inline__ int adb_is_absolute_host_path(const char* path) {
 #include <unistd.h>
 #include <fcntl.h>
 #include <stdarg.h>
+#include <netdb.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <string.h>
@@ -404,6 +417,48 @@ static __inline__  int  adb_creat(const char*  path, int  mode)
 #undef   creat
 #define  creat  ___xxx_creat
 
+// Helper for network_* functions.
+inline int _fd_set_error_str(int fd, std::string* error) {
+  if (fd == -1) {
+    *error = strerror(errno);
+  }
+  return fd;
+}
+
+inline int network_loopback_client(int port, int type, std::string* error) {
+  return _fd_set_error_str(socket_loopback_client(port, type), error);
+}
+
+inline int network_loopback_server(int port, int type, std::string* error) {
+  return _fd_set_error_str(socket_loopback_server(port, type), error);
+}
+
+inline int network_inaddr_any_server(int port, int type, std::string* error) {
+  return _fd_set_error_str(socket_inaddr_any_server(port, type), error);
+}
+
+inline int network_local_server(const char *name, int namespace_id, int type,
+                                std::string* error) {
+  return _fd_set_error_str(socket_local_server(name, namespace_id, type),
+                           error);
+}
+
+inline int network_connect(const std::string& host, int port, int type,
+                           int timeout, std::string* error) {
+  int getaddrinfo_error = 0;
+  int fd = socket_network_client_timeout(host.c_str(), port, type, timeout,
+                                         &getaddrinfo_error);
+  if (fd != -1) {
+    return fd;
+  }
+  if (getaddrinfo_error != 0) {
+    *error = gai_strerror(getaddrinfo_error);
+  } else {
+    *error = strerror(errno);
+  }
+  return -1;
+}
+
 static __inline__ int  adb_socket_accept(int  serverfd, struct sockaddr*  addr, socklen_t  *addrlen)
 {
     int fd;
diff --git a/sysdeps_win32.cpp b/sysdeps_win32.cpp
index a274892..9fdc24c 100644
--- a/sysdeps_win32.cpp
+++ b/sysdeps_win32.cpp
@@ -25,8 +25,15 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <memory>
+#include <string>
+
 #include <cutils/sockets.h>
 
+#include <base/logging.h>
+#include <base/stringprintf.h>
+#include <base/strings.h>
+
 #include "adb.h"
 
 extern void fatal(const char *fmt, ...);
@@ -80,6 +87,29 @@ static const FHClassRec _fh_socket_class = {
 
 #define assert(cond)  do { if (!(cond)) fatal( "assertion failed '%s' on %s:%ld\n", #cond, __FILE__, __LINE__ ); } while (0)
 
+std::string SystemErrorCodeToString(const DWORD error_code) {
+  const int kErrorMessageBufferSize = 256;
+  char msgbuf[kErrorMessageBufferSize];
+  DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
+  DWORD len = FormatMessageA(flags, nullptr, error_code, 0, msgbuf,
+                             arraysize(msgbuf), nullptr);
+  if (len == 0) {
+    return android::base::StringPrintf(
+        "Error (%lu) while retrieving error. (%lu)", GetLastError(),
+        error_code);
+  }
+
+  std::string msg(msgbuf);
+  // Messages returned by the system end with line breaks.
+  msg = android::base::Trim(msg);
+  // There are many Windows error messages compared to POSIX, so include the
+  // numeric error code for easier, quicker, accurate identification. Use
+  // decimal instead of hex because there are decimal ranges like 10000-11999
+  // for Winsock.
+  android::base::StringAppendF(&msg, " (%lu)", error_code);
+  return msg;
+}
+
 /**************************************************************************/
 /**************************************************************************/
 /*****                                                                *****/
@@ -253,6 +283,23 @@ _fh_close( FH   f )
     return 0;
 }
 
+// Deleter for unique_fh.
+class fh_deleter {
+ public:
+  void operator()(struct FHRec_* fh) {
+    // We're called from a destructor and destructors should not overwrite
+    // errno because callers may do:
+    //   errno = EBLAH;
+    //   return -1; // calls destructor, which should not overwrite errno
+    const int saved_errno = errno;
+    _fh_close(fh);
+    errno = saved_errno;
+  }
+};
+
+// Like std::unique_ptr, but calls _fh_close() instead of operator delete().
+typedef std::unique_ptr<struct FHRec_, fh_deleter> unique_fh;
+
 /**************************************************************************/
 /**************************************************************************/
 /*****                                                                *****/
@@ -467,21 +514,6 @@ int  adb_lseek(int  fd, int  pos, int  where)
 }
 
 
-int  adb_shutdown(int  fd)
-{
-    FH   f = _fh_from_int(fd, __func__);
-
-    if (!f || f->clazz != &_fh_socket_class) {
-        D("adb_shutdown: invalid fd %d\n", fd);
-        return -1;
-    }
-
-    D( "adb_shutdown: %s\n", f->name);
-    shutdown( f->fh_socket, SD_BOTH );
-    return 0;
-}
-
-
 int  adb_close(int  fd)
 {
     FH   f = _fh_from_int(fd, __func__);
@@ -505,29 +537,63 @@ int  adb_close(int  fd)
 
 #undef setsockopt
 
-static void _socket_set_errno( void ) {
-    switch (WSAGetLastError()) {
+static void _socket_set_errno( const DWORD err ) {
+    // The Windows C Runtime (MSVCRT.DLL) strerror() does not support a lot of
+    // POSIX and socket error codes, so this can only meaningfully map so much.
+    switch ( err ) {
     case 0:              errno = 0; break;
     case WSAEWOULDBLOCK: errno = EAGAIN; break;
     case WSAEINTR:       errno = EINTR; break;
+    case WSAEFAULT:      errno = EFAULT; break;
+    case WSAEINVAL:      errno = EINVAL; break;
+    case WSAEMFILE:      errno = EMFILE; break;
     default:
-        D( "_socket_set_errno: unhandled value %d\n", WSAGetLastError() );
         errno = EINVAL;
+        D( "_socket_set_errno: mapping Windows error code %lu to errno %d\n",
+           err, errno );
     }
 }
 
 static void _fh_socket_init( FH  f ) {
     f->fh_socket = INVALID_SOCKET;
     f->event     = WSACreateEvent();
+    if (f->event == WSA_INVALID_EVENT) {
+        D("WSACreateEvent failed: %s\n",
+          SystemErrorCodeToString(WSAGetLastError()).c_str());
+
+        // _event_socket_start assumes that this field is INVALID_HANDLE_VALUE
+        // on failure, instead of NULL which is what Windows really returns on
+        // error. It might be better to change all the other code to look for
+        // NULL, but that is a much riskier change.
+        f->event = INVALID_HANDLE_VALUE;
+    }
     f->mask      = 0;
 }
 
 static int _fh_socket_close( FH  f ) {
-    /* gently tell any peer that we're closing the socket */
-    shutdown( f->fh_socket, SD_BOTH );
-    closesocket( f->fh_socket );
-    f->fh_socket = INVALID_SOCKET;
-    CloseHandle( f->event );
+    if (f->fh_socket != INVALID_SOCKET) {
+        /* gently tell any peer that we're closing the socket */
+        if (shutdown(f->fh_socket, SD_BOTH) == SOCKET_ERROR) {
+            // If the socket is not connected, this returns an error. We want to
+            // minimize logging spam, so don't log these errors for now.
+#if 0
+            D("socket shutdown failed: %s\n",
+              SystemErrorCodeToString(WSAGetLastError()).c_str());
+#endif
+        }
+        if (closesocket(f->fh_socket) == SOCKET_ERROR) {
+            D("closesocket failed: %s\n",
+              SystemErrorCodeToString(WSAGetLastError()).c_str());
+        }
+        f->fh_socket = INVALID_SOCKET;
+    }
+    if (f->event != NULL) {
+        if (!CloseHandle(f->event)) {
+            D("CloseHandle failed: %s\n",
+              SystemErrorCodeToString(GetLastError()).c_str());
+        }
+        f->event = NULL;
+    }
     f->mask = 0;
     return 0;
 }
@@ -540,7 +606,10 @@ static int _fh_socket_lseek( FH  f, int pos, int origin ) {
 static int _fh_socket_read(FH f, void* buf, int len) {
     int  result = recv(f->fh_socket, reinterpret_cast<char*>(buf), len, 0);
     if (result == SOCKET_ERROR) {
-        _socket_set_errno();
+        const DWORD err = WSAGetLastError();
+        D("recv fd %d failed: %s\n", _fh_to_int(f),
+          SystemErrorCodeToString(err).c_str());
+        _socket_set_errno(err);
         result = -1;
     }
     return  result;
@@ -549,7 +618,10 @@ static int _fh_socket_read(FH f, void* buf, int len) {
 static int _fh_socket_write(FH f, const void* buf, int len) {
     int  result = send(f->fh_socket, reinterpret_cast<const char*>(buf), len, 0);
     if (result == SOCKET_ERROR) {
-        _socket_set_errno();
+        const DWORD err = WSAGetLastError();
+        D("send fd %d failed: %s\n", _fh_to_int(f),
+          SystemErrorCodeToString(err).c_str());
+        _socket_set_errno(err);
         result = -1;
     }
     return result;
@@ -570,31 +642,39 @@ static int  _winsock_init;
 static void
 _cleanup_winsock( void )
 {
+    // TODO: WSAStartup() might be called multiple times and this won't properly
+    // cleanup the right number of times. Plus, WSACleanup() probably doesn't
+    // make sense since it might interrupt other threads using Winsock (since
+    // our various threads are not explicitly cleanly shutdown at process exit).
     WSACleanup();
 }
 
 static void
 _init_winsock( void )
 {
+    // TODO: Multiple threads calling this may potentially cause multiple calls
+    // to WSAStartup() and multiple atexit() calls.
     if (!_winsock_init) {
         WSADATA  wsaData;
         int      rc = WSAStartup( MAKEWORD(2,2), &wsaData);
         if (rc != 0) {
-            fatal( "adb: could not initialize Winsock\n" );
+            fatal( "adb: could not initialize Winsock: %s",
+                   SystemErrorCodeToString( rc ).c_str());
         }
         atexit( _cleanup_winsock );
         _winsock_init = 1;
     }
 }
 
-int socket_loopback_client(int port, int type)
-{
-    FH  f = _fh_alloc( &_fh_socket_class );
+int network_loopback_client(int port, int type, std::string* error) {
     struct sockaddr_in addr;
     SOCKET  s;
 
-    if (!f)
+    unique_fh  f(_fh_alloc(&_fh_socket_class));
+    if (!f) {
+        *error = strerror(errno);
         return -1;
+    }
 
     if (!_winsock_init)
         _init_winsock();
@@ -606,32 +686,40 @@ int socket_loopback_client(int port, int type)
 
     s = socket(AF_INET, type, 0);
     if(s == INVALID_SOCKET) {
-        D("socket_loopback_client: could not create socket\n" );
-        _fh_close(f);
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("could not create socket: %s\n", error->c_str());
         return -1;
     }
-
     f->fh_socket = s;
-    if(connect(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
-        D("socket_loopback_client: could not connect to %s:%d\n", type != SOCK_STREAM ? "udp" : "tcp", port );
-        _fh_close(f);
+
+    if(connect(s, (struct sockaddr *) &addr, sizeof(addr)) == SOCKET_ERROR) {
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("could not connect to %s:%d: %s\n",
+          type != SOCK_STREAM ? "udp" : "tcp", port, error->c_str());
         return -1;
     }
-    snprintf( f->name, sizeof(f->name), "%d(lo-client:%s%d)", _fh_to_int(f), type != SOCK_STREAM ? "udp:" : "", port );
-    D( "socket_loopback_client: port %d type %s => fd %d\n", port, type != SOCK_STREAM ? "udp" : "tcp", _fh_to_int(f) );
-    return _fh_to_int(f);
+
+    const int fd = _fh_to_int(f.get());
+    snprintf( f->name, sizeof(f->name), "%d(lo-client:%s%d)", fd,
+              type != SOCK_STREAM ? "udp:" : "", port );
+    D( "port %d type %s => fd %d\n", port, type != SOCK_STREAM ? "udp" : "tcp",
+       fd );
+    f.release();
+    return fd;
 }
 
 #define LISTEN_BACKLOG 4
 
-int socket_loopback_server(int port, int type)
-{
-    FH   f = _fh_alloc( &_fh_socket_class );
+// interface_address is INADDR_LOOPBACK or INADDR_ANY.
+static int _network_server(int port, int type, u_long interface_address,
+                           std::string* error) {
     struct sockaddr_in addr;
     SOCKET  s;
     int  n;
 
+    unique_fh   f(_fh_alloc(&_fh_socket_class));
     if (!f) {
+        *error = strerror(errno);
         return -1;
     }
 
@@ -641,149 +729,151 @@ int socket_loopback_server(int port, int type)
     memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
     addr.sin_port = htons(port);
-    addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+    addr.sin_addr.s_addr = htonl(interface_address);
 
+    // TODO: Consider using dual-stack socket that can simultaneously listen on
+    // IPv4 and IPv6.
     s = socket(AF_INET, type, 0);
-    if(s == INVALID_SOCKET) return -1;
+    if (s == INVALID_SOCKET) {
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("could not create socket: %s\n", error->c_str());
+        return -1;
+    }
 
     f->fh_socket = s;
 
     n = 1;
-    setsockopt(s, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (const char*)&n, sizeof(n));
+    if (setsockopt(s, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (const char*)&n,
+                   sizeof(n)) == SOCKET_ERROR) {
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("setsockopt level %d optname %d failed: %s\n",
+          SOL_SOCKET, SO_EXCLUSIVEADDRUSE, error->c_str());
+        return -1;
+    }
 
-    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
-        _fh_close(f);
+    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) == SOCKET_ERROR) {
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("could not bind to %s:%d: %s\n",
+          type != SOCK_STREAM ? "udp" : "tcp", port, error->c_str());
         return -1;
     }
     if (type == SOCK_STREAM) {
-        int ret;
-
-        ret = listen(s, LISTEN_BACKLOG);
-        if (ret < 0) {
-            _fh_close(f);
+        if (listen(s, LISTEN_BACKLOG) == SOCKET_ERROR) {
+            *error = SystemErrorCodeToString(WSAGetLastError());
+            D("could not listen on %s:%d: %s\n",
+              type != SOCK_STREAM ? "udp" : "tcp", port, error->c_str());
             return -1;
         }
     }
-    snprintf( f->name, sizeof(f->name), "%d(lo-server:%s%d)", _fh_to_int(f), type != SOCK_STREAM ? "udp:" : "", port );
-    D( "socket_loopback_server: port %d type %s => fd %d\n", port, type != SOCK_STREAM ? "udp" : "tcp", _fh_to_int(f) );
-    return _fh_to_int(f);
+    const int fd = _fh_to_int(f.get());
+    snprintf( f->name, sizeof(f->name), "%d(%s-server:%s%d)", fd,
+              interface_address == INADDR_LOOPBACK ? "lo" : "any",
+              type != SOCK_STREAM ? "udp:" : "", port );
+    D( "port %d type %s => fd %d\n", port, type != SOCK_STREAM ? "udp" : "tcp",
+       fd );
+    f.release();
+    return fd;
 }
 
+int network_loopback_server(int port, int type, std::string* error) {
+    return _network_server(port, type, INADDR_LOOPBACK, error);
+}
 
-int socket_network_client_timeout(const char *host, int port, int type, int timeout,
-                                  int* getaddrinfo_error) {
-    FH  f = _fh_alloc( &_fh_socket_class );
-    if (!f) return -1;
-
-    if (!_winsock_init) _init_winsock();
+int network_inaddr_any_server(int port, int type, std::string* error) {
+    return _network_server(port, type, INADDR_ANY, error);
+}
 
-    hostent* hp = gethostbyname(host);
-    if(hp == 0) {
-        _fh_close(f);
+int network_connect(const std::string& host, int port, int type, int timeout, std::string* error) {
+    unique_fh f(_fh_alloc(&_fh_socket_class));
+    if (!f) {
+        *error = strerror(errno);
         return -1;
     }
 
-    sockaddr_in addr;
-    memset(&addr, 0, sizeof(addr));
-    addr.sin_family = hp->h_addrtype;
-    addr.sin_port = htons(port);
-    memcpy(&addr.sin_addr, hp->h_addr, hp->h_length);
+    if (!_winsock_init) _init_winsock();
 
-    SOCKET s = socket(hp->h_addrtype, type, 0);
-    if(s == INVALID_SOCKET) {
-        _fh_close(f);
-        return -1;
-    }
-    f->fh_socket = s;
+    struct addrinfo hints;
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = type;
 
-    // TODO: implement timeouts for Windows.
+    char port_str[16];
+    snprintf(port_str, sizeof(port_str), "%d", port);
 
-    if(connect(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
-        _fh_close(f);
+    struct addrinfo* addrinfo_ptr = nullptr;
+    if (getaddrinfo(host.c_str(), port_str, &hints, &addrinfo_ptr) != 0) {
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("could not resolve host '%s' and port %s: %s\n", host.c_str(),
+          port_str, error->c_str());
         return -1;
     }
+    std::unique_ptr<struct addrinfo, decltype(freeaddrinfo)*>
+        addrinfo(addrinfo_ptr, freeaddrinfo);
+    addrinfo_ptr = nullptr;
 
-    snprintf( f->name, sizeof(f->name), "%d(net-client:%s%d)", _fh_to_int(f), type != SOCK_STREAM ? "udp:" : "", port );
-    D( "socket_network_client_timeout: host '%s' port %d type %s => fd %d\n", host, port, type != SOCK_STREAM ? "udp" : "tcp", _fh_to_int(f) );
-    return _fh_to_int(f);
-}
-
-
-int socket_inaddr_any_server(int port, int type)
-{
-    FH  f = _fh_alloc( &_fh_socket_class );
-    struct sockaddr_in addr;
-    SOCKET  s;
-    int n;
-
-    if (!f)
-        return -1;
-
-    if (!_winsock_init)
-        _init_winsock();
-
-    memset(&addr, 0, sizeof(addr));
-    addr.sin_family = AF_INET;
-    addr.sin_port = htons(port);
-    addr.sin_addr.s_addr = htonl(INADDR_ANY);
-
-    s = socket(AF_INET, type, 0);
+    // TODO: Try all the addresses if there's more than one? This just uses
+    // the first. Or, could call WSAConnectByName() (Windows Vista and newer)
+    // which tries all addresses, takes a timeout and more.
+    SOCKET s = socket(addrinfo->ai_family, addrinfo->ai_socktype,
+                      addrinfo->ai_protocol);
     if(s == INVALID_SOCKET) {
-        _fh_close(f);
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("could not create socket: %s\n", error->c_str());
         return -1;
     }
-
     f->fh_socket = s;
-    n = 1;
-    setsockopt(s, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (const char*)&n, sizeof(n));
 
-    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
-        _fh_close(f);
+    // TODO: Implement timeouts for Windows. Seems like the default in theory
+    // (according to http://serverfault.com/a/671453) and in practice is 21 sec.
+    if(connect(s, addrinfo->ai_addr, addrinfo->ai_addrlen) == SOCKET_ERROR) {
+        *error = SystemErrorCodeToString(WSAGetLastError());
+        D("could not connect to %s:%s:%s: %s\n",
+          type != SOCK_STREAM ? "udp" : "tcp", host.c_str(), port_str,
+          error->c_str());
         return -1;
     }
 
-    if (type == SOCK_STREAM) {
-        int ret;
-
-        ret = listen(s, LISTEN_BACKLOG);
-        if (ret < 0) {
-            _fh_close(f);
-            return -1;
-        }
-    }
-    snprintf( f->name, sizeof(f->name), "%d(any-server:%s%d)", _fh_to_int(f), type != SOCK_STREAM ? "udp:" : "", port );
-    D( "socket_inaddr_server: port %d type %s => fd %d\n", port, type != SOCK_STREAM ? "udp" : "tcp", _fh_to_int(f) );
-    return _fh_to_int(f);
+    const int fd = _fh_to_int(f.get());
+    snprintf( f->name, sizeof(f->name), "%d(net-client:%s%d)", fd,
+              type != SOCK_STREAM ? "udp:" : "", port );
+    D( "host '%s' port %d type %s => fd %d\n", host.c_str(), port,
+       type != SOCK_STREAM ? "udp" : "tcp", fd );
+    f.release();
+    return fd;
 }
 
 #undef accept
 int  adb_socket_accept(int  serverfd, struct sockaddr*  addr, socklen_t  *addrlen)
 {
     FH   serverfh = _fh_from_int(serverfd, __func__);
-    FH   fh;
 
     if ( !serverfh || serverfh->clazz != &_fh_socket_class ) {
-        D( "adb_socket_accept: invalid fd %d\n", serverfd );
+        D("adb_socket_accept: invalid fd %d\n", serverfd);
+        errno = EBADF;
         return -1;
     }
 
-    fh = _fh_alloc( &_fh_socket_class );
+    unique_fh fh(_fh_alloc( &_fh_socket_class ));
     if (!fh) {
-        D( "adb_socket_accept: not enough memory to allocate accepted socket descriptor\n" );
+        PLOG(ERROR) << "adb_socket_accept: failed to allocate accepted socket "
+                       "descriptor";
         return -1;
     }
 
     fh->fh_socket = accept( serverfh->fh_socket, addr, addrlen );
     if (fh->fh_socket == INVALID_SOCKET) {
         const DWORD err = WSAGetLastError();
-        _fh_close( fh );
-        D( "adb_socket_accept: accept on fd %d return error %ld\n", serverfd, err );
+        LOG(ERROR) << "adb_socket_accept: accept on fd " << serverfd <<
+                      " failed: " + SystemErrorCodeToString(err);
+        _socket_set_errno( err );
         return -1;
     }
 
-    snprintf( fh->name, sizeof(fh->name), "%d(accept:%s)", _fh_to_int(fh), serverfh->name );
-    D( "adb_socket_accept on fd %d returns fd %d\n", serverfd, _fh_to_int(fh) );
-    return  _fh_to_int(fh);
+    const int fd = _fh_to_int(fh.get());
+    snprintf( fh->name, sizeof(fh->name), "%d(accept:%s)", fd, serverfh->name );
+    D( "adb_socket_accept on fd %d returns fd %d\n", serverfd, fd );
+    fh.release();
+    return  fd;
 }
 
 
@@ -793,10 +883,42 @@ int  adb_setsockopt( int  fd, int  level, int  optname, const void*  optval, soc
 
     if ( !fh || fh->clazz != &_fh_socket_class ) {
         D("adb_setsockopt: invalid fd %d\n", fd);
+        errno = EBADF;
         return -1;
     }
+    int result = setsockopt( fh->fh_socket, level, optname,
+                             reinterpret_cast<const char*>(optval), optlen );
+    if ( result == SOCKET_ERROR ) {
+        const DWORD err = WSAGetLastError();
+        D( "adb_setsockopt: setsockopt on fd %d level %d optname %d "
+           "failed: %s\n", fd, level, optname,
+           SystemErrorCodeToString(err).c_str() );
+        _socket_set_errno( err );
+        result = -1;
+    }
+    return result;
+}
+
 
-    return setsockopt( fh->fh_socket, level, optname, reinterpret_cast<const char*>(optval), optlen );
+int  adb_shutdown(int  fd)
+{
+    FH   f = _fh_from_int(fd, __func__);
+
+    if (!f || f->clazz != &_fh_socket_class) {
+        D("adb_shutdown: invalid fd %d\n", fd);
+        errno = EBADF;
+        return -1;
+    }
+
+    D( "adb_shutdown: %s\n", f->name);
+    if (shutdown(f->fh_socket, SD_BOTH) == SOCKET_ERROR) {
+        const DWORD err = WSAGetLastError();
+        D("socket shutdown fd %d failed: %s\n", fd,
+          SystemErrorCodeToString(err).c_str());
+        _socket_set_errno(err);
+        return -1;
+    }
+    return 0;
 }
 
 /**************************************************************************/
@@ -1199,16 +1321,19 @@ static const FHClassRec  _fh_socketpair_class =
 int  adb_socketpair(int sv[2]) {
     SocketPair pair;
 
-    FH fa = _fh_alloc(&_fh_socketpair_class);
-    FH fb = _fh_alloc(&_fh_socketpair_class);
-
-    if (!fa || !fb)
-        goto Fail;
+    unique_fh fa(_fh_alloc(&_fh_socketpair_class));
+    if (!fa) {
+        return -1;
+    }
+    unique_fh fb(_fh_alloc(&_fh_socketpair_class));
+    if (!fb) {
+        return -1;
+    }
 
     pair = reinterpret_cast<SocketPair>(malloc(sizeof(*pair)));
     if (pair == NULL) {
         D("adb_socketpair: not enough memory to allocate pipes\n" );
-        goto Fail;
+        return -1;
     }
 
     bip_buffer_init( &pair->a2b_bip );
@@ -1217,10 +1342,10 @@ int  adb_socketpair(int sv[2]) {
     fa->fh_pair = pair;
     fb->fh_pair = pair;
     pair->used  = 2;
-    pair->a_fd  = fa;
+    pair->a_fd  = fa.get();
 
-    sv[0] = _fh_to_int(fa);
-    sv[1] = _fh_to_int(fb);
+    sv[0] = _fh_to_int(fa.get());
+    sv[1] = _fh_to_int(fb.get());
 
     pair->a2b_bip.fdin  = sv[0];
     pair->a2b_bip.fdout = sv[1];
@@ -1230,12 +1355,9 @@ int  adb_socketpair(int sv[2]) {
     snprintf( fa->name, sizeof(fa->name), "%d(pair:%d)", sv[0], sv[1] );
     snprintf( fb->name, sizeof(fb->name), "%d(pair:%d)", sv[1], sv[0] );
     D( "adb_socketpair: returns (%d, %d)\n", sv[0], sv[1] );
+    fa.release();
+    fb.release();
     return 0;
-
-Fail:
-    _fh_close(fb);
-    _fh_close(fa);
-    return -1;
 }
 
 /**************************************************************************/
@@ -2083,6 +2205,7 @@ static void  _fh_socket_hook( FH  f, int  events, EventHook  hook )
     hook->check   = _event_socket_check;
     hook->peek    = _event_socket_peek;
 
+    // TODO: check return value?
     _event_socket_start( hook );
 }
 
diff --git a/transport_local.cpp b/transport_local.cpp
index 0dc9581..db9bedb 100644
--- a/transport_local.cpp
+++ b/transport_local.cpp
@@ -100,7 +100,7 @@ int local_connect_arbitrary_ports(int console_port, int adb_port, std::string* e
     }
 #endif
     if (fd < 0) {
-        fd = socket_loopback_client(adb_port, SOCK_STREAM);
+        fd = network_loopback_client(adb_port, SOCK_STREAM, error);
     }
 
     if (fd >= 0) {
@@ -144,9 +144,10 @@ static void *server_socket_thread(void * arg)
     serverfd = -1;
     for(;;) {
         if(serverfd == -1) {
-            serverfd = socket_inaddr_any_server(port, SOCK_STREAM);
+            std::string error;
+            serverfd = network_inaddr_any_server(port, SOCK_STREAM, &error);
             if(serverfd < 0) {
-                D("server: cannot bind socket yet: %s\n", strerror(errno));
+                D("server: cannot bind socket yet: %s\n", error.c_str());
                 adb_sleep_ms(1000);
                 continue;
             }