Make IPC channels track their peer process ID

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/types.h>
@@ skipping 285 matching lines @@
 //------------------------------------------------------------------------------
 
 #if defined(OS_LINUX)
 int Channel::ChannelImpl::global_pid_ = 0;
 #endif  // OS_LINUX
 
 Channel::ChannelImpl::ChannelImpl(const IPC::ChannelHandle& channel_handle,
                                   Mode mode, Listener* listener)
     : ChannelReader(listener),
       mode_(mode),
+      peer_pid_(base::kNullProcessId),
       is_blocked_on_write_(false),
       waiting_connect_(true),
       message_send_bytes_written_(0),
       server_listen_pipe_(-1),
       pipe_(-1),
       client_pipe_(-1),
 #if defined(IPC_USES_READWRITE)
       fd_pipe_(-1),
       remote_fd_pipe_(-1),
 #endif  // IPC_USES_READWRITE
@@ skipping 758 matching lines @@
     // subsequent file descriptor passing.
     DCHECK_EQ(msg.file_descriptor_set()->size(), 1U);
     base::FileDescriptor descriptor;
     if (!msg.ReadFileDescriptor(&iter, &descriptor)) {
       NOTREACHED();
     }
     fd_pipe_ = descriptor.fd;
     CHECK(descriptor.auto_close);
   }
 #endif  // IPC_USES_READWRITE
+  peer_pid_ = pid;
   listener()->OnChannelConnected(pid);
 }
 
 void Channel::ChannelImpl::Close() {
   // Close can be called multiple time, so we need to make sure we're
   // idempotent.
 
   ResetToAcceptingConnectionState();
 
   if (must_unlink_) {
@@ skipping 27 matching lines @@
 }
 
 void Channel::Close() {
   channel_impl_->Close();
 }
 
 void Channel::set_listener(Listener* listener) {
   channel_impl_->set_listener(listener);
 }
 
+base::ProcessId Channel::peer_pid() const {
+  return channel_impl_->peer_pid();
+}
+
 bool Channel::Send(Message* message) {
   return channel_impl_->Send(message);
 }
 
 int Channel::GetClientFileDescriptor() const {
   return channel_impl_->GetClientFileDescriptor();
 }
 
 int Channel::TakeClientFileDescriptor() {
   return channel_impl_->TakeClientFileDescriptor();
@@ skipping 34 matching lines @@
 
 
 #if defined(OS_LINUX)
 // static
 void Channel::SetGlobalPid(int pid) {
   ChannelImpl::SetGlobalPid(pid);
 }
 #endif  // OS_LINUX
 
 }  // namespace IPC