arc-bridge: Add the ARC Bridge Service

components/arc/arc_bridge_service.cc

Index: components/arc/arc_bridge_service.cc
diff --git a/components/arc/arc_bridge_service.cc b/components/arc/arc_bridge_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..34c215e93daf65ce4e67f333e2f3d5b924be6687
--- /dev/null
+++ b/components/arc/arc_bridge_service.cc
@@ -0,0 +1,283 @@
+// Copyright 2015 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 "components/arc/arc_bridge_service.h"
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/prefs/pref_registry_simple.h"
+#include "base/prefs/pref_service.h"
+#include "base/task_runner_util.h"
+#include "base/thread_task_runner_handle.h"
+#include "chromeos/dbus/dbus_method_call_status.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+#include "chromeos/dbus/session_manager_client.h"
+#include "components/arc/common/arc_host_messages.h"
+#include "components/arc/common/arc_instance_messages.h"
+#include "ipc/ipc_channel.h"
+
+namespace arc {
+
+namespace {
+
+const base::FilePath::CharType kArcBridgeSocketPath[] =
+    FILE_PATH_LITERAL("/home/chronos/ArcBridge/bridge.sock");
+
+// Weak pointer.  This class is owned by ChromeBrowserMainPartsChromeos.
+ArcBridgeService* g_arc_bridge_service = nullptr;
+
+}  // namespace
+
+ArcBridgeService::ArcBridgeService(
+    const scoped_refptr<base::SingleThreadTaskRunner>& ipc_task_runner,
+    const scoped_refptr<base::SequencedTaskRunner>& file_task_runner)
+    : origin_task_runner_(base::ThreadTaskRunnerHandle::Get()),
+      ipc_task_runner_(ipc_task_runner),
+      file_task_runner_(file_task_runner),
+      session_started_(false),
+      available_(false),
+      state_(State::STOPPED),
+      weak_factory_(this) {
+  DCHECK(!g_arc_bridge_service);
+  g_arc_bridge_service = this;
+}
+
+ArcBridgeService::~ArcBridgeService() {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK(state_ == State::STOPPING || state_ == State::STOPPED);
+  DCHECK(g_arc_bridge_service);
+  g_arc_bridge_service = nullptr;
+}
+
+// static
+ArcBridgeService* ArcBridgeService::Get() {
+  DCHECK(g_arc_bridge_service);
+  DCHECK(g_arc_bridge_service->origin_task_runner_->RunsTasksOnCurrentThread());
+  return g_arc_bridge_service;
+}
+
+void ArcBridgeService::DetectAvailability() {
+  chromeos::SessionManagerClient* session_manager_client =
+      chromeos::DBusThreadManager::Get()->GetSessionManagerClient();
+  session_manager_client->CheckArcAvailability(base::Bind(
+      &ArcBridgeService::OnArcAvailable, weak_factory_.GetWeakPtr()));
+}
+
+void ArcBridgeService::HandleStartup() {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  session_started_ = true;
+  PrerequisitesChanged();
+}
+
+void ArcBridgeService::Shutdown() {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  session_started_ = false;
+  PrerequisitesChanged();
+}
+
+void ArcBridgeService::AddObserver(Observer* observer) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  observer_list_.AddObserver(observer);
+}
+
+void ArcBridgeService::RemoveObserver(Observer* observer) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  observer_list_.RemoveObserver(observer);
+}
+
+void ArcBridgeService::PrerequisitesChanged() {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ == State::STOPPED) {
+    if (!available_ || !session_started_)
+      return;
+    SocketConnect(base::FilePath(kArcBridgeSocketPath));
+  } else {
+    if (available_ && session_started_)
+      return;
+    StopInstance();
+  }
+}
+
+void ArcBridgeService::StopInstance() {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ == State::STOPPED || state_ == State::STOPPING) {
+    VLOG(1) << "StopInstance() called when ARC is not running";
+    return;
+  }
+  if (state_ == State::CONNECTED || state_ == State::CONNECTING) {
+    // This was stopped before the D-Bus command to start the instance. Just
+    // close the socket (if it was opened).
+    if (state_ == State::CONNECTED) {
+      ipc_channel_.reset();
+    }
+    SetState(State::STOPPED);
+    return;
+  }
+
+  SetState(State::STOPPING);
+  chromeos::SessionManagerClient* session_manager_client =
+      chromeos::DBusThreadManager::Get()->GetSessionManagerClient();
+  session_manager_client->StopArcInstance(base::Bind(
+      &ArcBridgeService::OnInstanceStopped, weak_factory_.GetWeakPtr()));
+}
+
+bool ArcBridgeService::RegisterInputDevice(const std::string& name,
+                                           const std::string& device_type,
+                                           base::ScopedFD fd) {
+  DCHECK(ipc_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ != State::READY) {
+    LOG(ERROR) << "Called RegisterInputDevice when the service is not ready";
+    return false;
+  }
+  return ipc_channel_->Send(new ArcInstanceMsg_RegisterInputDevice(
+      name, device_type, base::FileDescriptor(fd.Pass())));
+}
+
+void ArcBridgeService::SocketConnect(const base::FilePath& socket_path) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ != State::STOPPED) {
+    VLOG(1) << "SocketConnect() called when instance is not stopped";
+    return;
+  }
+  SetState(State::CONNECTING);
+  base::PostTaskAndReplyWithResult(
+      file_task_runner_.get(), FROM_HERE,
+      base::Bind(&base::CreateDirectory, socket_path.DirName()),
+      base::Bind(&ArcBridgeService::SocketConnectAfterEnsureParentDirectory,
+                 weak_factory_.GetWeakPtr(), socket_path));
+}
+
+void ArcBridgeService::SocketConnectAfterEnsureParentDirectory(
+    const base::FilePath& socket_path,
+    bool directory_present) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ != State::CONNECTING) {
+    VLOG(1) << "StopInstance() called while connecting";
+    return;
+  }
+  if (!directory_present) {
+    LOG(ERROR) << "Error creating directory for " << socket_path.value();
+    StopInstance();
+    return;
+  }
+
+  if (!Connect(IPC::ChannelHandle(socket_path.value()),
+               IPC::Channel::MODE_OPEN_NAMED_SERVER)) {
+    LOG(ERROR) << "Error connecting to " << socket_path.value();
+    StopInstance();
+    return;
+  }
+
+  base::PostTaskAndReplyWithResult(
+      file_task_runner_.get(), FROM_HERE,
+      // TODO(lhchavez): Tighten the security around the socket by tying it to
+      // the user the instance will run as.
+      base::Bind(&base::SetPosixFilePermissions, socket_path, 0777),
+      base::Bind(&ArcBridgeService::SocketConnectAfterSetSocketPermissions,
+                 weak_factory_.GetWeakPtr(), socket_path));
+}
+
+bool ArcBridgeService::Connect(const IPC::ChannelHandle& handle,
+                               IPC::Channel::Mode mode) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ != State::CONNECTING) {
+    VLOG(1) << "StopInstance() called while connecting";
+    return false;
+  }
+
+  ipc_channel_ =
+      IPC::ChannelProxy::Create(handle, mode, this, ipc_task_runner_.get());
+  if (!ipc_channel_)
+    return false;
+  SetState(State::CONNECTED);
+  return true;
+}
+
+void ArcBridgeService::SocketConnectAfterSetSocketPermissions(
+    const base::FilePath& socket_path,
+    bool socket_permissions_success) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ != State::CONNECTED) {
+    VLOG(1) << "StopInstance() called while connecting";
+    return;
+  }
+
+  if (!socket_permissions_success) {
+    LOG(ERROR) << "Error setting socket permissions for "
+               << socket_path.value();
+    StopInstance();
+    return;
+  }
+
+  SetState(State::STARTING);
+  chromeos::SessionManagerClient* session_manager_client =
+      chromeos::DBusThreadManager::Get()->GetSessionManagerClient();
+  session_manager_client->StartArcInstance(
+      socket_path.value(), base::Bind(&ArcBridgeService::OnInstanceStarted,
+                                      weak_factory_.GetWeakPtr()));
+}
+
+void ArcBridgeService::OnInstanceStarted(bool success) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ != State::STARTING) {
+    VLOG(1) << "StopInstance() called while connecting";
+    return;
+  }
+  if (!success) {
+    LOG(ERROR) << "ARC instance unable to start. Shutting down the bridge";
+    StopInstance();
+    return;
+  }
+}
+
+void ArcBridgeService::OnInstanceReady() {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (state_ != State::STARTING) {
+    VLOG(1) << "StopInstance() called while connecting";
+    return;
+  }
+  SetState(State::READY);
+}
+
+void ArcBridgeService::SetState(State state) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  // DCHECK on enum classes not supported.
+  DCHECK(state_ != state);
+  state_ = state;
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnStateChanged(state_));
+}
+
+bool ArcBridgeService::OnMessageReceived(const IPC::Message& message) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  bool handled = true;
+
+  IPC_BEGIN_MESSAGE_MAP(ArcBridgeService, message)
+    IPC_MESSAGE_HANDLER(ArcInstanceHostMsg_InstanceReady, OnInstanceReady)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+
+  if (!handled)
+    LOG(ERROR) << "Invalid message with type = " << message.type();
+  return handled;
+}
+
+void ArcBridgeService::OnArcAvailable(bool available) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  if (available_ == available)
+    return;
+  available_ = available;
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnAvailableChanged(available_));
+  PrerequisitesChanged();
+}
+
+void ArcBridgeService::OnInstanceStopped(bool success) {
+  DCHECK(origin_task_runner_->RunsTasksOnCurrentThread());
+  // STOPPING is the only valid state for this function.
+  // DCHECK on enum classes not supported.
+  DCHECK(state_ == State::STOPPING);
+  ipc_channel_.reset();
+  SetState(State::STOPPED);
+}
+
+}  // namespace arc