Fix posix IPC channel hanging problem.

ipc/ipc_channel_posix.cc

 // 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 "ipc/ipc_channel_posix.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <stddef.h>
 #include <sys/socket.h>
@@ skipping 504 matching lines @@
            << " with type " << message->type()
            << " (" << output_queue_.size() << " in queue)";
 
 #ifdef IPC_MESSAGE_LOG_ENABLED
   Logging::GetInstance()->OnSendMessage(message, "");
 #endif  // IPC_MESSAGE_LOG_ENABLED
 
   message->TraceMessageBegin();
   output_queue_.push(message);
   if (!is_blocked_on_write_ && !waiting_connect_) {
-    return ProcessOutgoingMessages();
+    if (!ProcessOutgoingMessages()) {
+      ClosePipeOnError();
+      return false;
+    }
   }
 
   return true;
 }
 
 int Channel::ChannelImpl::GetClientFileDescriptor() {
   base::AutoLock lock(client_pipe_lock_);
   return client_pipe_;
 }
 
@@ skipping 164 matching lines @@
 bool Channel::ChannelImpl::AcceptConnection() {
   base::MessageLoopForIO::current()->WatchFileDescriptor(
       pipe_, true, base::MessageLoopForIO::WATCH_READ, &read_watcher_, this);
   QueueHelloMessage();
 
   if (mode_ & MODE_CLIENT_FLAG) {
     // If we are a client we want to send a hello message out immediately.
     // In server mode we will send a hello message when we receive one from a
     // client.
     waiting_connect_ = false;
     return ProcessOutgoingMessages();

[Scott Hess - ex-Googler, 2013/10/22 23:52:46]

Could this have the same race condition if the other end closes after accept but
before ProcessOutgoingMessages()?

[hubbe, 2013/10/23 00:29:28]

Yes, I think so.
I'll see if I can trigger this in a test.

   } else if (mode_ & MODE_SERVER_FLAG) {
     waiting_connect_ = true;
     return true;
   } else {
     NOTREACHED();
     return false;
   }
 }
 
 void Channel::ChannelImpl::ClosePipeOnError() {
@@ skipping 380 matching lines @@
 
 
 #if defined(OS_LINUX)
 // static
 void Channel::SetGlobalPid(int pid) {
   ChannelImpl::SetGlobalPid(pid);
 }
 #endif  // OS_LINUX
 
 }  // namespace IPC