Accept inbound connections on unix domain socket

mojo/shell/external_application_listener.cc

+// Copyright 2014 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 "mojo/shell/external_application_listener.h"
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/sequenced_task_runner.h"
+#include "base/tracked_objects.h"
+#include "mojo/embedder/channel_init.h"
+#include "mojo/public/cpp/bindings/error_handler.h"
+#include "mojo/shell/external_application_registrar.mojom.h"
+#include "net/base/net_errors.h"
+#include "net/socket/socket_descriptor.h"
+
+namespace mojo {
+namespace shell {
+
+const char ExternalApplicationListener::kDefaultListenSocketPath[] =
+    "/var/run/mojo/system_socket";
+
+class ExternalApplicationListener::RegistrarImpl
+    : public InterfaceImpl<ExternalApplicationRegistrar> {
+ public:
+  explicit RegistrarImpl(const RegisterCallback& callback);
+  virtual ~RegistrarImpl() MOJO_OVERRIDE;
+
+  virtual void OnConnectionError() MOJO_OVERRIDE;
+
+  embedder::ChannelInit channel_init;
+
+ private:
+  virtual void Register(const String& app_url,
+                        InterfaceRequest<Shell> shell,
+                        const mojo::Closure& callback) MOJO_OVERRIDE;
+
+  const RegisterCallback register_callback_;
+};
+
+ExternalApplicationListener::ExternalApplicationListener(
+    const scoped_refptr<base::SequencedTaskRunner>& shell_runner,
+    const scoped_refptr<base::SequencedTaskRunner>& io_runner)
+    : shell_runner_(shell_runner),
+      io_runner_(io_runner),
+      signal_on_listening_(true, false),
+      weak_ptr_factory_(this) {
+  DCHECK(shell_runner_.get() && shell_runner_->RunsTasksOnCurrentThread());
+  DCHECK(io_runner_.get());
+  listener_thread_checker_.DetachFromThread();  // Will attach in StartListener.
+}
+
+ExternalApplicationListener::~ExternalApplicationListener() {
+  DCHECK(register_thread_checker_.CalledOnValidThread());
+  weak_ptr_factory_.InvalidateWeakPtrs();
+
+  // listener_ needs to be destroyed on io_runner_, and it has to die before
+  // this object does, as it holds a pointer back to this instance.
+  base::WaitableEvent stop_listening_event(true, false);
+  io_runner_->PostTask(FROM_HERE,
+                       base::Bind(&ExternalApplicationListener::StopListening,
+                                  base::Unretained(this),
+                                  &stop_listening_event));
+  stop_listening_event.Wait();
+}
+
+void ExternalApplicationListener::ListenInBackground(
+    const base::FilePath& listen_socket_path,
+    const RegisterCallback& register_callback) {
+  DCHECK(register_thread_checker_.CalledOnValidThread());
+  ListenInBackgroundWithErrorCallback(
+      listen_socket_path, register_callback, ErrorCallback());
+}
+
+void ExternalApplicationListener::ListenInBackgroundWithErrorCallback(
+    const base::FilePath& listen_socket_path,
+    const RegisterCallback& register_callback,
+    const ErrorCallback& error_callback) {
+  DCHECK(register_thread_checker_.CalledOnValidThread());
+  register_callback_ = register_callback;
+  error_callback_ = error_callback;
+
+  io_runner_->PostTask(FROM_HERE,
+                       base::Bind(&ExternalApplicationListener::StartListening,
+                                  base::Unretained(this),
+                                  listen_socket_path));
+}
+
+void ExternalApplicationListener::WaitForListening() {
+  DCHECK(register_thread_checker_.CalledOnValidThread());
+  signal_on_listening_.Wait();
+}
+
+void ExternalApplicationListener::StartListening(
+    const base::FilePath& listen_socket_path) {
+  CHECK_EQ(base::MessageLoop::current()->type(), base::MessageLoop::TYPE_IO);
+  DCHECK(listener_thread_checker_.CalledOnValidThread());
+  listener_.reset(new IncomingConnectionListener(listen_socket_path, this));
+  listener_->StartListening();
+}
+
+void ExternalApplicationListener::StopListening(base::WaitableEvent* event) {
+  DCHECK(listener_thread_checker_.CalledOnValidThread());
+  listener_.reset();
+  event->Signal();
+}
+
+void ExternalApplicationListener::OnListening(int rv) {
+  DCHECK(listener_thread_checker_.CalledOnValidThread());
+  signal_on_listening_.Signal();
+  shell_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(
+          &ExternalApplicationListener::RunErrorCallbackIfListeningFailed,
+          weak_ptr_factory_.GetWeakPtr(),
+          rv));
+}
+
+void ExternalApplicationListener::OnConnection(net::SocketDescriptor incoming) {
+  DCHECK(listener_thread_checker_.CalledOnValidThread());
+  shell_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&ExternalApplicationListener::CreatePipeAndBindToRegistrarImpl,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 incoming));
+}
+
+void ExternalApplicationListener::RunErrorCallbackIfListeningFailed(int rv) {
+  DCHECK(register_thread_checker_.CalledOnValidThread());
+  if (rv != net::OK && !error_callback_.is_null()) {
+    error_callback_.Run(rv);
+  }
+}
+
+void ExternalApplicationListener::CreatePipeAndBindToRegistrarImpl(
+    net::SocketDescriptor incoming_socket) {
+  DCHECK(register_thread_checker_.CalledOnValidThread());
+
+  DVLOG(1) << "Accepted incoming connection";
+  scoped_ptr<RegistrarImpl> registrar(new RegistrarImpl(register_callback_));
+  // Passes ownership of incoming_socket to registrar->channel_init.
+  mojo::ScopedMessagePipeHandle message_pipe =
+      registrar->channel_init.Init(incoming_socket, io_runner_);
+  CHECK(message_pipe.is_valid());
+
+  BindToPipe(registrar.release(), message_pipe.Pass());
+}
+
+ExternalApplicationListener::RegistrarImpl::RegistrarImpl(
+    const RegisterCallback& callback)
+    : register_callback_(callback) {
+}
+
+ExternalApplicationListener::RegistrarImpl::~RegistrarImpl() {
+}
+
+void ExternalApplicationListener::RegistrarImpl::OnConnectionError() {
+  channel_init.WillDestroySoon();
+}
+
+void ExternalApplicationListener::RegistrarImpl::Register(
+    const String& app_url,
+    InterfaceRequest<Shell> shell,
+    const mojo::Closure& callback) {
+  register_callback_.Run(app_url.To<GURL>(), shell.PassMessagePipe());
+  callback.Run();
+}
+
+}  // namespace shell
+}  // namespace mojo