[Chromoting] The desktop process now creates a pre-connected pipe and passes (with some help of the…

remoting/host/desktop_session_agent_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 "remoting/host/desktop_session_agent.h"
+
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "base/eintr_wrapper.h"
+#include "base/single_thread_task_runner.h"
+#include "base/stringprintf.h"
+#include "ipc/ipc_channel.h"
+#include "ipc/ipc_channel_proxy.h"
+
+namespace remoting {
+
+// Provides screen/audio capturing and input injection services for
+// the network process.
+class DesktopSessionAgentPosix : public DesktopSessionAgent {
+ public:
+  DesktopSessionAgentPosix(
+      scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
+      scoped_refptr<base::SingleThreadTaskRunner> io_task_runner);
+  virtual ~DesktopSessionAgentPosix();
+
+ protected:
+  virtual bool DoCreateNetworkChannel(
+      IPC::PlatformFileForTransit* client_out,
+      scoped_ptr<IPC::ChannelProxy>* server_out) OVERRIDE;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DesktopSessionAgentPosix);
+};
+
+DesktopSessionAgentPosix::DesktopSessionAgentPosix(
+    scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> io_task_runner)
+    : DesktopSessionAgent(caller_task_runner, io_task_runner) {
+}
+
+DesktopSessionAgentPosix::~DesktopSessionAgentPosix() {
+}
+
+bool DesktopSessionAgentPosix::DoCreateNetworkChannel(
+    IPC::PlatformFileForTransit* client_out,
+    scoped_ptr<IPC::ChannelProxy>* server_out) {
+  // Create a socket pair.
+  int pipe_fds[2];
+  if (socketpair(AF_UNIX, SOCK_STREAM, 0, pipe_fds) != 0) {
+    PLOG(ERROR) << "socketpair()";
+    return false;
+  }
+
+  // Set both ends to be non-blocking.
+  if (fcntl(pipe_fds[0], F_SETFL, O_NONBLOCK) == -1 ||

[Sergey Ulanov, 2012/10/24 20:12:01]

Looks like this duplicates code from SocketPair() in
src/ipc/ipc_channel_posix.cc . Can we avoid duplicating it?

[alexeypa (please no reviews), 2012/10/24 21:41:51]

I'll follow up with a separate CL.

+      fcntl(pipe_fds[1], F_SETFL, O_NONBLOCK) == -1) {
+    PLOG(ERROR) << "fcntl(O_NONBLOCK)";
+    if (HANDLE_EINTR(close(pipe_fds[0])) < 0)
+      PLOG(ERROR) << "close()";
+    if (HANDLE_EINTR(close(pipe_fds[1])) < 0)
+      PLOG(ERROR) << "close()";
+    return false;
+  }
+
+  // Generate a unique name for the channel.
+  std::string channel_name = IPC::Channel::GenerateUniqueRandomChannelID();
+  std::string socket_name = base::StringPrintf("/var/tmp/DesktopSessionAgent%s",

[Sergey Ulanov, 2012/10/24 20:12:01]

Not sure why we need this. We pass IPC::ChannelProxy a file descriptor for the
socket anyway, so it will use this name only in logs, but will not be creating
named socket, right? In that case the name doesn't need to be an actual path,
and there is no need to make it unique. Something like "nameless _socket" should
work just fine.

[alexeypa (please no reviews), 2012/10/24 21:41:51]

Done.

+                                               channel_name.c_str());
+
+  // Wrap the pipe into an IPC channel.
+  base::FileDescriptor fd(pipe_fds[0], false);
+  IPC::ChannelHandle handle(socket_name, fd);
+  scoped_ptr<IPC::ChannelProxy> server(new IPC::ChannelProxy(

[Sergey Ulanov, 2012/10/24 20:12:01]

nit: server_out->reset()?

[alexeypa (please no reviews), 2012/10/24 21:41:51]

Done.

+      IPC::ChannelHandle(socket_name, fd),
+      IPC::Channel::MODE_SERVER,
+      this,
+      io_task_runner()));
+
+  *client_out = base::FileDescriptor(pipe_fds[1], false);
+  *server_out = server.Pass();
+  return true;
+}
+
+// static
+scoped_ptr<DesktopSessionAgent> DesktopSessionAgent::Create(
+    scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> io_task_runner) {
+  return scoped_ptr<DesktopSessionAgent>(new DesktopSessionAgentPosix(
+      caller_task_runner, io_task_runner));
+}
+
+}  // namespace remoting