remoting/host/remoting_me2me

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This source file includes following definitions.
InitWithCommandLine
OnConfigUpdated
OnConfigWatcherError
StartOnNetworkThread
SigTermHandler
CreateAuthenticatorFactory
OnMessageReceived
OnChannelError
StartOnUiThread
ShutdownOnUiThread
OnUnknownHostIdError
OnHeartbeatSuccessful
OnHostDeleted
OnInitializePairingRegistry
ApplyConfig
OnPolicyUpdate
OnHostDomainPolicyUpdate
OnUsernamePolicyUpdate
OnNatPolicyUpdate
OnCurtainPolicyUpdate
OnHostTalkGadgetPrefixPolicyUpdate
OnHostTokenUrlPolicyUpdate
OnPairingPolicyUpdate
OnGnubbyAuthPolicyUpdate
StartHost
OnAuthFailed
RestartHost
ShutdownHost
ScheduleHostShutdown
ShutdownOnNetworkThread
OnCrash
HostProcessMain
main
// 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.
//
// This file implements a standalone host process for Me2Me.

#include <string>

#include "base/at_exit.h"
#include "base/bind.h"
#include "base/callback.h"
#include "base/command_line.h"
#include "base/debug/alias.h"
#include "base/file_util.h"
#include "base/files/file_path.h"
#include "base/memory/scoped_ptr.h"
#include "base/message_loop/message_loop.h"
#include "base/single_thread_task_runner.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/synchronization/waitable_event.h"
#include "base/threading/thread.h"
#include "build/build_config.h"
#include "crypto/nss_util.h"
#include "ipc/ipc_channel.h"
#include "ipc/ipc_channel_proxy.h"
#include "ipc/ipc_listener.h"
#include "media/base/media.h"
#include "net/base/network_change_notifier.h"
#include "net/socket/client_socket_factory.h"
#include "net/socket/ssl_server_socket.h"
#include "net/url_request/url_fetcher.h"
#include "remoting/base/auto_thread_task_runner.h"
#include "remoting/base/breakpad.h"
#include "remoting/base/constants.h"
#include "remoting/base/logging.h"
#include "remoting/base/rsa_key_pair.h"
#include "remoting/host/branding.h"
#include "remoting/host/chromoting_host.h"
#include "remoting/host/chromoting_host_context.h"
#include "remoting/host/chromoting_messages.h"
#include "remoting/host/config_file_watcher.h"
#include "remoting/host/config_watcher.h"
#include "remoting/host/desktop_environment.h"
#include "remoting/host/desktop_session_connector.h"
#include "remoting/host/dns_blackhole_checker.h"
#include "remoting/host/heartbeat_sender.h"
#include "remoting/host/host_change_notification_listener.h"
#include "remoting/host/host_config.h"
#include "remoting/host/host_event_logger.h"
#include "remoting/host/host_exit_codes.h"
#include "remoting/host/host_main.h"
#include "remoting/host/host_status_sender.h"
#include "remoting/host/ipc_constants.h"
#include "remoting/host/ipc_desktop_environment.h"
#include "remoting/host/ipc_host_event_logger.h"
#include "remoting/host/json_host_config.h"
#include "remoting/host/log_to_server.h"
#include "remoting/host/logging.h"
#include "remoting/host/me2me_desktop_environment.h"
#include "remoting/host/pairing_registry_delegate.h"
#include "remoting/host/policy_hack/policy_watcher.h"
#include "remoting/host/service_urls.h"
#include "remoting/host/session_manager_factory.h"
#include "remoting/host/signaling_connector.h"
#include "remoting/host/token_validator_factory_impl.h"
#include "remoting/host/usage_stats_consent.h"
#include "remoting/host/username.h"
#include "remoting/jingle_glue/network_settings.h"
#include "remoting/jingle_glue/xmpp_signal_strategy.h"
#include "remoting/protocol/me2me_host_authenticator_factory.h"
#include "remoting/protocol/pairing_registry.h"
#include "remoting/protocol/token_validator.h"

#if defined(OS_POSIX)
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>
#include "base/file_descriptor_posix.h"
#include "remoting/host/pam_authorization_factory_posix.h"
#include "remoting/host/posix/signal_handler.h"
#endif  // defined(OS_POSIX)

#if defined(OS_MACOSX)
#include "base/mac/scoped_cftyperef.h"
#endif  // defined(OS_MACOSX)

#if defined(OS_LINUX)
#include "remoting/host/audio_capturer_linux.h"
#endif  // defined(OS_LINUX)

#if defined(OS_WIN)
#include <commctrl.h>
#include "base/win/registry.h"
#include "base/win/scoped_handle.h"
#include "remoting/host/pairing_registry_delegate_win.h"
#include "remoting/host/win/session_desktop_environment.h"
#endif  // defined(OS_WIN)

#if defined(TOOLKIT_GTK)
#include "ui/gfx/gtk_util.h"
#endif  // defined(TOOLKIT_GTK)

using remoting::protocol::PairingRegistry;

namespace {

// This is used for tagging system event logs.
const char kApplicationName[] = "chromoting";

#if defined(OS_LINUX)
// The command line switch used to pass name of the pipe to capture audio on
// linux.
const char kAudioPipeSwitchName[] = "audio-pipe-name";

// The command line switch used to pass name of the unix domain socket used to
// listen for gnubby requests.
const char kAuthSocknameSwitchName[] = "ssh-auth-sockname";
#endif  // defined(OS_LINUX)

// The command line switch used by the parent to request the host to signal it
// when it is successfully started.
const char kSignalParentSwitchName[] = "signal-parent";

// Value used for --host-config option to indicate that the path must be read
// from stdin.
const char kStdinConfigPath[] = "-";

}  // namespace

namespace remoting {

class HostProcess
    : public ConfigWatcher::Delegate,
      public HeartbeatSender::Listener,
      public HostChangeNotificationListener::Listener,
      public IPC::Listener,
      public base::RefCountedThreadSafe<HostProcess> {
 public:
  HostProcess(scoped_ptr<ChromotingHostContext> context,
              int* exit_code_out);

  // ConfigWatcher::Delegate interface.
  virtual void OnConfigUpdated(const std::string& serialized_config) OVERRIDE;
  virtual void OnConfigWatcherError() OVERRIDE;

  // IPC::Listener implementation.
  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
  virtual void OnChannelError() OVERRIDE;

  // HeartbeatSender::Listener overrides.
  virtual void OnHeartbeatSuccessful() OVERRIDE;
  virtual void OnUnknownHostIdError() OVERRIDE;

  // HostChangeNotificationListener::Listener overrides.
  virtual void OnHostDeleted() OVERRIDE;

  // Initializes the pairing registry on Windows.
  void OnInitializePairingRegistry(
      IPC::PlatformFileForTransit privileged_key,
      IPC::PlatformFileForTransit unprivileged_key);

 private:
  enum HostState {
    // Host process has just been started. Waiting for config and policies to be
    // read from the disk.
    HOST_INITIALIZING,

    // Host is started and running.
    HOST_STARTED,

    // Host is being stopped and will need to be started again.
    HOST_STOPPING_TO_RESTART,

    // Host is being stopped.
    HOST_STOPPING,

    // Host has been stopped.
    HOST_STOPPED,

    // Allowed state transitions:
    //   INITIALIZING->STARTED
    //   INITIALIZING->STOPPED
    //   STARTED->STOPPING_TO_RESTART
    //   STARTED->STOPPING
    //   STOPPING_TO_RESTART->STARTED
    //   STOPPING_TO_RESTART->STOPPING
    //   STOPPING->STOPPED
    //   STOPPED->STARTED
    //
    // |host_| must be NULL in INITIALIZING and STOPPED states and not-NULL in
    // all other states.
  };

  friend class base::RefCountedThreadSafe<HostProcess>;
  virtual ~HostProcess();

  void StartOnNetworkThread();

#if defined(OS_POSIX)
  // Callback passed to RegisterSignalHandler() to handle SIGTERM events.
  void SigTermHandler(int signal_number);
#endif

  // Called to initialize resources on the UI thread.
  void StartOnUiThread();

  // Initializes IPC control channel and config file path from |cmd_line|.
  // Called on the UI thread.
  bool InitWithCommandLine(const CommandLine* cmd_line);

  // Called on the UI thread to start monitoring the configuration file.
  void StartWatchingConfigChanges();

  // Called on the network thread to set the host's Authenticator factory.
  void CreateAuthenticatorFactory();

  // Tear down resources that run on the UI thread.
  void ShutdownOnUiThread();

  // Applies the host config, returning true if successful.
  bool ApplyConfig(scoped_ptr<JsonHostConfig> config);

  void OnPolicyUpdate(scoped_ptr<base::DictionaryValue> policies);
  bool OnHostDomainPolicyUpdate(const std::string& host_domain);
  bool OnUsernamePolicyUpdate(bool curtain_required,
                              bool username_match_required);
  bool OnNatPolicyUpdate(bool nat_traversal_enabled);
  void OnCurtainPolicyUpdate(bool curtain_required);
  bool OnHostTalkGadgetPrefixPolicyUpdate(const std::string& talkgadget_prefix);
  bool OnHostTokenUrlPolicyUpdate(
      const GURL& token_url,
      const GURL& token_validation_url,
      const std::string& token_validation_cert_issuer);
  bool OnPairingPolicyUpdate(bool pairing_enabled);
  bool OnGnubbyAuthPolicyUpdate(bool enable_gnubby_auth);

  void StartHost();

  void OnAuthFailed();

  void RestartHost();

  // Stops the host and shuts down the process with the specified |exit_code|.
  void ShutdownHost(HostExitCodes exit_code);

  void ScheduleHostShutdown();

  void ShutdownOnNetworkThread();

  // Crashes the process in response to a daemon's request. The daemon passes
  // the location of the code that detected the fatal error resulted in this
  // request.
  void OnCrash(const std::string& function_name,
               const std::string& file_name,
               const int& line_number);

  scoped_ptr<ChromotingHostContext> context_;

  // Created on the UI thread but used from the network thread.
  scoped_ptr<net::NetworkChangeNotifier> network_change_notifier_;

  // Accessed on the UI thread.
  scoped_ptr<IPC::ChannelProxy> daemon_channel_;

  // XMPP server/remoting bot configuration (initialized from the command line).
  XmppSignalStrategy::XmppServerConfig xmpp_server_config_;
  std::string directory_bot_jid_;

  // Created on the UI thread but used from the network thread.
  base::FilePath host_config_path_;
  std::string host_config_;
  scoped_ptr<DesktopEnvironmentFactory> desktop_environment_factory_;

  // Accessed on the network thread.
  HostState state_;

  scoped_ptr<ConfigWatcher> config_watcher_;

  std::string host_id_;
  protocol::SharedSecretHash host_secret_hash_;
  scoped_refptr<RsaKeyPair> key_pair_;
  std::string oauth_refresh_token_;
  std::string serialized_config_;
  std::string host_owner_;
  bool use_service_account_;
  scoped_ptr<policy_hack::PolicyWatcher> policy_watcher_;
  bool allow_nat_traversal_;
  std::string talkgadget_prefix_;
  bool allow_pairing_;

  bool curtain_required_;
  ThirdPartyAuthConfig third_party_auth_config_;
  bool enable_gnubby_auth_;

  scoped_ptr<OAuthTokenGetter> oauth_token_getter_;
  scoped_ptr<XmppSignalStrategy> signal_strategy_;
  scoped_ptr<SignalingConnector> signaling_connector_;
  scoped_ptr<HeartbeatSender> heartbeat_sender_;
  scoped_ptr<HostStatusSender> host_status_sender_;
  scoped_ptr<HostChangeNotificationListener> host_change_notification_listener_;
  scoped_ptr<LogToServer> log_to_server_;
  scoped_ptr<HostEventLogger> host_event_logger_;

  scoped_ptr<ChromotingHost> host_;

  // Used to keep this HostProcess alive until it is shutdown.
  scoped_refptr<HostProcess> self_;

#if defined(REMOTING_MULTI_PROCESS)
  DesktopSessionConnector* desktop_session_connector_;
#endif  // defined(REMOTING_MULTI_PROCESS)

  int* exit_code_out_;
  bool signal_parent_;

  scoped_ptr<PairingRegistry::Delegate> pairing_registry_delegate_;
};

HostProcess::HostProcess(scoped_ptr<ChromotingHostContext> context,
                         int* exit_code_out)
    : context_(context.Pass()),
      state_(HOST_INITIALIZING),
      use_service_account_(false),
      allow_nat_traversal_(true),
      allow_pairing_(true),
      curtain_required_(false),
      enable_gnubby_auth_(false),
#if defined(REMOTING_MULTI_PROCESS)
      desktop_session_connector_(NULL),
#endif  // defined(REMOTING_MULTI_PROCESS)
      self_(this),
      exit_code_out_(exit_code_out),
      signal_parent_(false) {
  StartOnUiThread();
}

HostProcess::~HostProcess() {
  // Verify that UI components have been torn down.
  DCHECK(!config_watcher_);
  DCHECK(!daemon_channel_);
  DCHECK(!desktop_environment_factory_);

  // We might be getting deleted on one of the threads the |host_context| owns,
  // so we need to post it back to the caller thread to safely join & delete the
  // threads it contains.  This will go away when we move to AutoThread.
  // |context_release()| will null |context_| before the method is invoked, so
  // we need to pull out the task-runner on which to call DeleteSoon first.
  scoped_refptr<base::SingleThreadTaskRunner> task_runner =
      context_->ui_task_runner();
  task_runner->DeleteSoon(FROM_HERE, context_.release());
}

bool HostProcess::InitWithCommandLine(const CommandLine* cmd_line) {
#if defined(REMOTING_MULTI_PROCESS)
  // Parse the handle value and convert it to a handle/file descriptor.
  std::string channel_name =
      cmd_line->GetSwitchValueASCII(kDaemonPipeSwitchName);

  int pipe_handle = 0;
  if (channel_name.empty() ||
      !base::StringToInt(channel_name, &pipe_handle)) {
    LOG(ERROR) << "Invalid '" << kDaemonPipeSwitchName
               << "' value: " << channel_name;
    return false;
  }

#if defined(OS_WIN)
  base::win::ScopedHandle pipe(reinterpret_cast<HANDLE>(pipe_handle));
  IPC::ChannelHandle channel_handle(pipe);
#elif defined(OS_POSIX)
  base::FileDescriptor pipe(pipe_handle, true);
  IPC::ChannelHandle channel_handle(channel_name, pipe);
#endif  // defined(OS_POSIX)

  // Connect to the daemon process.
  daemon_channel_.reset(new IPC::ChannelProxy(
      channel_handle,
      IPC::Channel::MODE_CLIENT,
      this,
      context_->network_task_runner()));
#else  // !defined(REMOTING_MULTI_PROCESS)
  // Connect to the daemon process.
  std::string channel_name =
      cmd_line->GetSwitchValueASCII(kDaemonPipeSwitchName);
  if (!channel_name.empty()) {
    daemon_channel_.reset(
        new IPC::ChannelProxy(channel_name,
                              IPC::Channel::MODE_CLIENT,
                              this,
                              context_->network_task_runner().get()));
  }

  if (cmd_line->HasSwitch(kHostConfigSwitchName)) {
    host_config_path_ = cmd_line->GetSwitchValuePath(kHostConfigSwitchName);

    // Read config from stdin if necessary.
    if (host_config_path_ == base::FilePath(kStdinConfigPath)) {
      char buf[4096];
      size_t len;
      while ((len = fread(buf, 1, sizeof(buf), stdin)) > 0) {
        host_config_.append(buf, len);
      }
    }
  } else {
    base::FilePath default_config_dir = remoting::GetConfigDir();
    host_config_path_ = default_config_dir.Append(kDefaultHostConfigFile);
  }

  if (host_config_path_ != base::FilePath(kStdinConfigPath) &&
      !base::PathExists(host_config_path_)) {
    LOG(ERROR) << "Can't find host config at " << host_config_path_.value();
    return false;
  }
#endif  // !defined(REMOTING_MULTI_PROCESS)

  // Ignore certificate requests - the host currently has no client certificate
  // support, so ignoring certificate requests allows connecting to servers that
  // request, but don't require, a certificate (optional client authentication).
  net::URLFetcher::SetIgnoreCertificateRequests(true);

  ServiceUrls* service_urls = ServiceUrls::GetInstance();
  bool xmpp_server_valid = net::ParseHostAndPort(
      service_urls->xmpp_server_address(),
      &xmpp_server_config_.host, &xmpp_server_config_.port);
  if (!xmpp_server_valid) {
    LOG(ERROR) << "Invalid XMPP server: " <<
        service_urls->xmpp_server_address();
    return false;
  }
  xmpp_server_config_.use_tls = service_urls->xmpp_server_use_tls();
  directory_bot_jid_ = service_urls->directory_bot_jid();

  signal_parent_ = cmd_line->HasSwitch(kSignalParentSwitchName);

  return true;
}

void HostProcess::OnConfigUpdated(
    const std::string& serialized_config) {
  if (!context_->network_task_runner()->BelongsToCurrentThread()) {
    context_->network_task_runner()->PostTask(FROM_HERE,
        base::Bind(&HostProcess::OnConfigUpdated, this, serialized_config));
    return;
  }

  // Filter out duplicates.
  if (serialized_config_ == serialized_config)
    return;

  HOST_LOG << "Processing new host configuration.";

  serialized_config_ = serialized_config;
  scoped_ptr<JsonHostConfig> config(new JsonHostConfig(base::FilePath()));
  if (!config->SetSerializedData(serialized_config)) {
    LOG(ERROR) << "Invalid configuration.";
    ShutdownHost(kInvalidHostConfigurationExitCode);
    return;
  }

  if (!ApplyConfig(config.Pass())) {
    LOG(ERROR) << "Failed to apply the configuration.";
    ShutdownHost(kInvalidHostConfigurationExitCode);
    return;
  }

  if (state_ == HOST_INITIALIZING) {
    // TODO(sergeyu): Currently OnPolicyUpdate() assumes that host config is
    // already loaded so PolicyWatcher has to be started here. Separate policy
    // loading from policy verifications and move |policy_watcher_|
    // initialization to StartOnNetworkThread().
    policy_watcher_.reset(
        policy_hack::PolicyWatcher::Create(context_->file_task_runner()));
    policy_watcher_->StartWatching(
        base::Bind(&HostProcess::OnPolicyUpdate, base::Unretained(this)));
  } else if (state_ == HOST_STARTED) {
    // TODO(sergeyu): Here we assume that PIN is the only part of the config
    // that may change while the service is running. Change ApplyConfig() to
    // detect other changes in the config and restart host if necessary here.
    CreateAuthenticatorFactory();
  }
}

void HostProcess::OnConfigWatcherError() {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());
  ShutdownHost(kInvalidHostConfigurationExitCode);
}

void HostProcess::StartOnNetworkThread() {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

#if !defined(REMOTING_MULTI_PROCESS)
  if (host_config_path_ == base::FilePath(kStdinConfigPath)) {
    // Process config we've read from stdin.
    OnConfigUpdated(host_config_);
  } else {
    // Start watching the host configuration file.
    config_watcher_.reset(new ConfigFileWatcher(context_->network_task_runner(),
                                                context_->file_task_runner(),
                                                host_config_path_));
    config_watcher_->Watch(this);
  }
#endif  // !defined(REMOTING_MULTI_PROCESS)

#if defined(OS_POSIX)
  remoting::RegisterSignalHandler(
      SIGTERM,
      base::Bind(&HostProcess::SigTermHandler, base::Unretained(this)));
#endif  // defined(OS_POSIX)
}

#if defined(OS_POSIX)
void HostProcess::SigTermHandler(int signal_number) {
  DCHECK(signal_number == SIGTERM);
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());
  HOST_LOG << "Caught SIGTERM: Shutting down...";
  ShutdownHost(kSuccessExitCode);
}
#endif  // OS_POSIX

void HostProcess::CreateAuthenticatorFactory() {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (state_ != HOST_STARTED)
    return;

  std::string local_certificate = key_pair_->GenerateCertificate();
  if (local_certificate.empty()) {
    LOG(ERROR) << "Failed to generate host certificate.";
    ShutdownHost(kInitializationFailed);
    return;
  }

  scoped_refptr<PairingRegistry> pairing_registry = NULL;
  if (allow_pairing_) {
    if (!pairing_registry_delegate_)
      pairing_registry_delegate_ = CreatePairingRegistryDelegate();

    if (pairing_registry_delegate_) {
      pairing_registry = new PairingRegistry(context_->file_task_runner(),
                                             pairing_registry_delegate_.Pass());
    }
  }

  scoped_ptr<protocol::AuthenticatorFactory> factory;

  if (third_party_auth_config_.is_empty()) {
    factory = protocol::Me2MeHostAuthenticatorFactory::CreateWithSharedSecret(
        use_service_account_, host_owner_, local_certificate, key_pair_,
        host_secret_hash_, pairing_registry);

  } else if (third_party_auth_config_.is_valid()) {
    scoped_ptr<protocol::TokenValidatorFactory> token_validator_factory(
        new TokenValidatorFactoryImpl(
            third_party_auth_config_,
            key_pair_, context_->url_request_context_getter()));
    factory = protocol::Me2MeHostAuthenticatorFactory::CreateWithThirdPartyAuth(
        use_service_account_, host_owner_, local_certificate, key_pair_,
        token_validator_factory.Pass());

  } else {
    // TODO(rmsousa): If the policy is bad the host should not go online. It
    // should keep running, but not connected, until the policies are fixed.
    // Having it show up as online and then reject all clients is misleading.
    LOG(ERROR) << "One of the third-party token URLs is empty or invalid. "
               << "Host will reject all clients until policies are corrected. "
               << "TokenUrl: " << third_party_auth_config_.token_url << ", "
               << "TokenValidationUrl: "
               << third_party_auth_config_.token_validation_url;
    factory = protocol::Me2MeHostAuthenticatorFactory::CreateRejecting();
  }

#if defined(OS_POSIX)
  // On Linux and Mac, perform a PAM authorization step after authentication.
  factory.reset(new PamAuthorizationFactory(factory.Pass()));
#endif
  host_->SetAuthenticatorFactory(factory.Pass());

  host_->set_pairing_registry(pairing_registry);
}

// IPC::Listener implementation.
bool HostProcess::OnMessageReceived(const IPC::Message& message) {
  DCHECK(context_->ui_task_runner()->BelongsToCurrentThread());

#if defined(REMOTING_MULTI_PROCESS)
  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP(HostProcess, message)
    IPC_MESSAGE_HANDLER(ChromotingDaemonMsg_Crash, OnCrash)
    IPC_MESSAGE_HANDLER(ChromotingDaemonNetworkMsg_Configuration,
                        OnConfigUpdated)
    IPC_MESSAGE_HANDLER(ChromotingDaemonNetworkMsg_InitializePairingRegistry,
                        OnInitializePairingRegistry)
    IPC_MESSAGE_FORWARD(
        ChromotingDaemonNetworkMsg_DesktopAttached,
        desktop_session_connector_,
        DesktopSessionConnector::OnDesktopSessionAgentAttached)
    IPC_MESSAGE_FORWARD(ChromotingDaemonNetworkMsg_TerminalDisconnected,
                        desktop_session_connector_,
                        DesktopSessionConnector::OnTerminalDisconnected)
    IPC_MESSAGE_UNHANDLED(handled = false)
  IPC_END_MESSAGE_MAP()

  CHECK(handled) << "Received unexpected IPC type: " << message.type();
  return handled;

#else  // !defined(REMOTING_MULTI_PROCESS)
  return false;
#endif  // !defined(REMOTING_MULTI_PROCESS)
}

void HostProcess::OnChannelError() {
  DCHECK(context_->ui_task_runner()->BelongsToCurrentThread());

  // Shutdown the host if the daemon process disconnects the IPC channel.
  context_->network_task_runner()->PostTask(
      FROM_HERE,
      base::Bind(&HostProcess::ShutdownHost, this, kSuccessExitCode));
}

void HostProcess::StartOnUiThread() {
  DCHECK(context_->ui_task_runner()->BelongsToCurrentThread());

  if (!InitWithCommandLine(CommandLine::ForCurrentProcess())) {
    // Shutdown the host if the command line is invalid.
    context_->network_task_runner()->PostTask(
        FROM_HERE, base::Bind(&HostProcess::ShutdownHost, this,
                              kUsageExitCode));
    return;
  }

#if defined(OS_LINUX)
  // If an audio pipe is specific on the command-line then initialize
  // AudioCapturerLinux to capture from it.
  base::FilePath audio_pipe_name = CommandLine::ForCurrentProcess()->
      GetSwitchValuePath(kAudioPipeSwitchName);
  if (!audio_pipe_name.empty()) {
    remoting::AudioCapturerLinux::InitializePipeReader(
        context_->audio_task_runner(), audio_pipe_name);
  }

  base::FilePath gnubby_socket_name = CommandLine::ForCurrentProcess()->
      GetSwitchValuePath(kAuthSocknameSwitchName);
  if (!gnubby_socket_name.empty())
    remoting::GnubbyAuthHandler::SetGnubbySocketName(gnubby_socket_name);
#endif  // defined(OS_LINUX)

  // Create a desktop environment factory appropriate to the build type &
  // platform.
#if defined(OS_WIN)
  IpcDesktopEnvironmentFactory* desktop_environment_factory =
      new IpcDesktopEnvironmentFactory(
          context_->audio_task_runner(),
          context_->network_task_runner(),
          context_->video_capture_task_runner(),
          context_->network_task_runner(),
          daemon_channel_.get());
  desktop_session_connector_ = desktop_environment_factory;
#else  // !defined(OS_WIN)
  DesktopEnvironmentFactory* desktop_environment_factory =
      new Me2MeDesktopEnvironmentFactory(
          context_->network_task_runner(),
          context_->input_task_runner(),
          context_->ui_task_runner());
#endif  // !defined(OS_WIN)

  desktop_environment_factory_.reset(desktop_environment_factory);
  desktop_environment_factory_->SetEnableGnubbyAuth(enable_gnubby_auth_);

  context_->network_task_runner()->PostTask(
      FROM_HERE,
      base::Bind(&HostProcess::StartOnNetworkThread, this));
}

void HostProcess::ShutdownOnUiThread() {
  DCHECK(context_->ui_task_runner()->BelongsToCurrentThread());

  // Tear down resources that need to be torn down on the UI thread.
  network_change_notifier_.reset();
  daemon_channel_.reset();
  desktop_environment_factory_.reset();

  // It is now safe for the HostProcess to be deleted.
  self_ = NULL;

#if defined(OS_LINUX)
  // Cause the global AudioPipeReader to be freed, otherwise the audio
  // thread will remain in-use and prevent the process from exiting.
  // TODO(wez): DesktopEnvironmentFactory should own the pipe reader.
  // See crbug.com/161373 and crbug.com/104544.
  AudioCapturerLinux::InitializePipeReader(NULL, base::FilePath());
#endif
}

// Overridden from HeartbeatSender::Listener
void HostProcess::OnUnknownHostIdError() {
  LOG(ERROR) << "Host ID not found.";
  ShutdownHost(kInvalidHostIdExitCode);
}

void HostProcess::OnHeartbeatSuccessful() {
  HOST_LOG << "Host ready to receive connections.";
#if defined(OS_POSIX)
  if (signal_parent_) {
    kill(getppid(), SIGUSR1);
    signal_parent_ = false;
  }
#endif
}

void HostProcess::OnHostDeleted() {
  LOG(ERROR) << "Host was deleted from the directory.";
  ShutdownHost(kInvalidHostIdExitCode);
}

void HostProcess::OnInitializePairingRegistry(
    IPC::PlatformFileForTransit privileged_key,
    IPC::PlatformFileForTransit unprivileged_key) {
  DCHECK(!pairing_registry_delegate_);

#if defined(OS_WIN)
  // Initialize the pairing registry delegate.
  scoped_ptr<PairingRegistryDelegateWin> delegate(
      new PairingRegistryDelegateWin());
  bool result = delegate->SetRootKeys(
      reinterpret_cast<HKEY>(
          IPC::PlatformFileForTransitToPlatformFile(privileged_key)),
      reinterpret_cast<HKEY>(
          IPC::PlatformFileForTransitToPlatformFile(unprivileged_key)));
  if (!result)
    return;

  pairing_registry_delegate_ = delegate.PassAs<PairingRegistry::Delegate>();
#else  // !defined(OS_WIN)
  NOTREACHED();
#endif  // !defined(OS_WIN)
}

// Applies the host config, returning true if successful.
bool HostProcess::ApplyConfig(scoped_ptr<JsonHostConfig> config) {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (!config->GetString(kHostIdConfigPath, &host_id_)) {
    LOG(ERROR) << "host_id is not defined in the config.";
    return false;
  }

  std::string key_base64;
  if (!config->GetString(kPrivateKeyConfigPath, &key_base64)) {
    LOG(ERROR) << "Private key couldn't be read from the config file.";
    return false;
  }

  key_pair_ = RsaKeyPair::FromString(key_base64);
  if (!key_pair_.get()) {
    LOG(ERROR) << "Invalid private key in the config file.";
    return false;
  }

  std::string host_secret_hash_string;
  if (!config->GetString(kHostSecretHashConfigPath,
                         &host_secret_hash_string)) {
    host_secret_hash_string = "plain:";
  }

  if (!host_secret_hash_.Parse(host_secret_hash_string)) {
    LOG(ERROR) << "Invalid host_secret_hash.";
    return false;
  }

  // Use an XMPP connection to the Talk network for session signalling.
  if (!config->GetString(kXmppLoginConfigPath, &xmpp_server_config_.username) ||
      !(config->GetString(kXmppAuthTokenConfigPath,
                          &xmpp_server_config_.auth_token) ||
        config->GetString(kOAuthRefreshTokenConfigPath,
                          &oauth_refresh_token_))) {
    LOG(ERROR) << "XMPP credentials are not defined in the config.";
    return false;
  }

  if (!oauth_refresh_token_.empty()) {
    // SignalingConnector is responsible for getting OAuth token.
    xmpp_server_config_.auth_token = "";
    xmpp_server_config_.auth_service = "oauth2";
  } else if (!config->GetString(kXmppAuthServiceConfigPath,
                                &xmpp_server_config_.auth_service)) {
    // For the me2me host, we default to ClientLogin token for chromiumsync
    // because earlier versions of the host had no HTTP stack with which to
    // request an OAuth2 access token.
    xmpp_server_config_.auth_service = kChromotingTokenDefaultServiceName;
  }

  if (config->GetString(kHostOwnerConfigPath, &host_owner_)) {
    // Service account configs have a host_owner, different from the xmpp_login.
    use_service_account_ = true;
  } else {
    // User credential configs only have an xmpp_login, which is also the owner.
    host_owner_ = xmpp_server_config_.username;
    use_service_account_ = false;
  }
  return true;
}

void HostProcess::OnPolicyUpdate(scoped_ptr<base::DictionaryValue> policies) {
  // TODO(rmsousa): Consolidate all On*PolicyUpdate methods into this one.
  // TODO(sergeyu): Currently polices are verified only when they are loaded.
  // Separate policy loading from policy verifications - this will allow to
  // check policies again later, e.g. when host config changes.

  if (!context_->network_task_runner()->BelongsToCurrentThread()) {
    context_->network_task_runner()->PostTask(FROM_HERE, base::Bind(
        &HostProcess::OnPolicyUpdate, this, base::Passed(&policies)));
    return;
  }

  bool restart_required = false;
  bool bool_value;
  std::string string_value;
  if (policies->GetString(policy_hack::PolicyWatcher::kHostDomainPolicyName,
                          &string_value)) {
    restart_required |= OnHostDomainPolicyUpdate(string_value);
  }
  bool curtain_required = false;
  if (policies->GetBoolean(
          policy_hack::PolicyWatcher::kHostRequireCurtainPolicyName,
          &curtain_required)) {
    OnCurtainPolicyUpdate(curtain_required);
  }
  if (policies->GetBoolean(
      policy_hack::PolicyWatcher::kHostMatchUsernamePolicyName,
      &bool_value)) {
    restart_required |= OnUsernamePolicyUpdate(curtain_required, bool_value);
  }
  if (policies->GetBoolean(policy_hack::PolicyWatcher::kNatPolicyName,
                           &bool_value)) {
    restart_required |= OnNatPolicyUpdate(bool_value);
  }
  if (policies->GetString(
          policy_hack::PolicyWatcher::kHostTalkGadgetPrefixPolicyName,
          &string_value)) {
    restart_required |= OnHostTalkGadgetPrefixPolicyUpdate(string_value);
  }
  std::string token_url_string, token_validation_url_string;
  std::string token_validation_cert_issuer;
  if (policies->GetString(
          policy_hack::PolicyWatcher::kHostTokenUrlPolicyName,
          &token_url_string) &&
      policies->GetString(
          policy_hack::PolicyWatcher::kHostTokenValidationUrlPolicyName,
          &token_validation_url_string) &&
      policies->GetString(
          policy_hack::PolicyWatcher::kHostTokenValidationCertIssuerPolicyName,
          &token_validation_cert_issuer)) {
    restart_required |= OnHostTokenUrlPolicyUpdate(
        GURL(token_url_string), GURL(token_validation_url_string),
        token_validation_cert_issuer);
  }
  if (policies->GetBoolean(
          policy_hack::PolicyWatcher::kHostAllowClientPairing,
          &bool_value)) {
    restart_required |= OnPairingPolicyUpdate(bool_value);
  }
  if (policies->GetBoolean(
          policy_hack::PolicyWatcher::kHostAllowGnubbyAuthPolicyName,
          &bool_value))
    restart_required |= OnGnubbyAuthPolicyUpdate(bool_value);

  if (state_ == HOST_INITIALIZING) {
    StartHost();
  } else if (state_ == HOST_STARTED && restart_required) {
    RestartHost();
  }
}

bool HostProcess::OnHostDomainPolicyUpdate(const std::string& host_domain) {
  // Returns true if the host has to be restarted after this policy update.
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  HOST_LOG << "Policy sets host domain: " << host_domain;

  if (!host_domain.empty() &&
      !EndsWith(host_owner_, std::string("@") + host_domain, false)) {
    ShutdownHost(kInvalidHostDomainExitCode);
  }
  return false;
}

bool HostProcess::OnUsernamePolicyUpdate(bool curtain_required,
                                         bool host_username_match_required) {
  // Returns false: never restart the host after this policy update.
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (host_username_match_required) {
    HOST_LOG << "Policy requires host username match.";
    std::string username = GetUsername();
    bool shutdown = username.empty() ||
        !StartsWithASCII(host_owner_, username + std::string("@"),
                         false);

#if defined(OS_MACOSX)
    // On Mac, we run as root at the login screen, so the username won't match.
    // However, there's no need to enforce the policy at the login screen, as
    // the client will have to reconnect if a login occurs.
    if (shutdown && getuid() == 0) {
      shutdown = false;
    }
#endif

    // Curtain-mode on Windows presents the standard OS login prompt to the user
    // for each connection, removing the need for an explicit user-name matching
    // check.
#if defined(OS_WIN) && defined(REMOTING_RDP_SESSION)
    if (curtain_required)
      return false;
#endif  // defined(OS_WIN) && defined(REMOTING_RDP_SESSION)

    // Shutdown the host if the username does not match.
    if (shutdown) {
      LOG(ERROR) << "The host username does not match.";
      ShutdownHost(kUsernameMismatchExitCode);
    }
  } else {
    HOST_LOG << "Policy does not require host username match.";
  }

  return false;
}

bool HostProcess::OnNatPolicyUpdate(bool nat_traversal_enabled) {
  // Returns true if the host has to be restarted after this policy update.
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (allow_nat_traversal_ != nat_traversal_enabled) {
    if (nat_traversal_enabled)
      HOST_LOG << "Policy enables NAT traversal.";
    else
      HOST_LOG << "Policy disables NAT traversal.";
    allow_nat_traversal_ = nat_traversal_enabled;
    return true;
  }
  return false;
}

void HostProcess::OnCurtainPolicyUpdate(bool curtain_required) {
  // Returns true if the host has to be restarted after this policy update.
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

#if defined(OS_MACOSX)
  if (curtain_required) {
    // When curtain mode is in effect on Mac, the host process runs in the
    // user's switched-out session, but launchd will also run an instance at
    // the console login screen.  Even if no user is currently logged-on, we
    // can't support remote-access to the login screen because the current host
    // process model disconnects the client during login, which would leave
    // the logged in session un-curtained on the console until they reconnect.
    //
    // TODO(jamiewalch): Fix this once we have implemented the multi-process
    // daemon architecture (crbug.com/134894)
    if (getuid() == 0) {
      LOG(ERROR) << "Running the host in the console login session is yet not "
                    "supported.";
      ShutdownHost(kLoginScreenNotSupportedExitCode);
      return;
    }
  }
#endif

  if (curtain_required_ != curtain_required) {
    if (curtain_required)
      HOST_LOG << "Policy requires curtain-mode.";
    else
      HOST_LOG << "Policy does not require curtain-mode.";
    curtain_required_ = curtain_required;
    if (host_)
      host_->SetEnableCurtaining(curtain_required_);
  }
}

bool HostProcess::OnHostTalkGadgetPrefixPolicyUpdate(
    const std::string& talkgadget_prefix) {
  // Returns true if the host has to be restarted after this policy update.
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (talkgadget_prefix != talkgadget_prefix_) {
    HOST_LOG << "Policy sets talkgadget prefix: " << talkgadget_prefix;
    talkgadget_prefix_ = talkgadget_prefix;
    return true;
  }
  return false;
}

bool HostProcess::OnHostTokenUrlPolicyUpdate(
    const GURL& token_url,
    const GURL& token_validation_url,
    const std::string& token_validation_cert_issuer) {
  // Returns true if the host has to be restarted after this policy update.
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (third_party_auth_config_.token_url != token_url ||
      third_party_auth_config_.token_validation_url != token_validation_url ||
      third_party_auth_config_.token_validation_cert_issuer !=
      token_validation_cert_issuer) {
    HOST_LOG << "Policy sets third-party token URLs: "
             << "TokenUrl: " << token_url << ", "
             << "TokenValidationUrl: " << token_validation_url
             << "TokenValidationCertificateIssuer: "
             << token_validation_cert_issuer;
    third_party_auth_config_.token_url = token_url;
    third_party_auth_config_.token_validation_url = token_validation_url;
    third_party_auth_config_.token_validation_cert_issuer =
        token_validation_cert_issuer;
    return true;
  }

  return false;
}

bool HostProcess::OnPairingPolicyUpdate(bool allow_pairing) {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (allow_pairing_ == allow_pairing)
    return false;

  if (allow_pairing)
    HOST_LOG << "Policy enables client pairing.";
  else
    HOST_LOG << "Policy disables client pairing.";
  allow_pairing_ = allow_pairing;
  return true;
}

bool HostProcess::OnGnubbyAuthPolicyUpdate(bool enable_gnubby_auth) {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  if (enable_gnubby_auth_ == enable_gnubby_auth)
    return false;

  if (enable_gnubby_auth) {
    HOST_LOG << "Policy enables gnubby auth.";
  } else {
    HOST_LOG << "Policy disables gnubby auth.";
  }
  enable_gnubby_auth_ = enable_gnubby_auth;

  if (desktop_environment_factory_)
    desktop_environment_factory_->SetEnableGnubbyAuth(enable_gnubby_auth);

  return true;
}

void HostProcess::StartHost() {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());
  DCHECK(!host_);
  DCHECK(!signal_strategy_.get());
  DCHECK(state_ == HOST_INITIALIZING || state_ == HOST_STOPPING_TO_RESTART ||
         state_ == HOST_STOPPED) << state_;
  state_ = HOST_STARTED;

  signal_strategy_.reset(
      new XmppSignalStrategy(net::ClientSocketFactory::GetDefaultFactory(),
                             context_->url_request_context_getter(),
                             xmpp_server_config_));

  scoped_ptr<DnsBlackholeChecker> dns_blackhole_checker(
      new DnsBlackholeChecker(context_->url_request_context_getter(),
                              talkgadget_prefix_));

  // Create a NetworkChangeNotifier for use by the signaling connector.
  network_change_notifier_.reset(net::NetworkChangeNotifier::Create());

  signaling_connector_.reset(new SignalingConnector(
      signal_strategy_.get(),
      dns_blackhole_checker.Pass(),
      base::Bind(&HostProcess::OnAuthFailed, this)));

  if (!oauth_refresh_token_.empty()) {
    scoped_ptr<OAuthTokenGetter::OAuthCredentials> oauth_credentials;
    oauth_credentials.reset(
        new OAuthTokenGetter::OAuthCredentials(
            xmpp_server_config_.username, oauth_refresh_token_,
            use_service_account_));

    oauth_token_getter_.reset(new OAuthTokenGetter(
        oauth_credentials.Pass(), context_->url_request_context_getter()));

    signaling_connector_->EnableOAuth(oauth_token_getter_.get());
  }

  NetworkSettings network_settings(
      allow_nat_traversal_ ?
      NetworkSettings::NAT_TRAVERSAL_ENABLED :
      NetworkSettings::NAT_TRAVERSAL_DISABLED);
  if (!allow_nat_traversal_) {
    network_settings.min_port = NetworkSettings::kDefaultMinPort;
    network_settings.max_port = NetworkSettings::kDefaultMaxPort;
  }

  host_.reset(new ChromotingHost(
      signal_strategy_.get(),
      desktop_environment_factory_.get(),
      CreateHostSessionManager(signal_strategy_.get(), network_settings,
                               context_->url_request_context_getter()),
      context_->audio_task_runner(),
      context_->input_task_runner(),
      context_->video_capture_task_runner(),
      context_->video_encode_task_runner(),
      context_->network_task_runner(),
      context_->ui_task_runner()));

  // TODO(simonmorris): Get the maximum session duration from a policy.
#if defined(OS_LINUX)
  host_->SetMaximumSessionDuration(base::TimeDelta::FromHours(20));
#endif

  heartbeat_sender_.reset(new HeartbeatSender(
      this, host_id_, signal_strategy_.get(), key_pair_,
      directory_bot_jid_));

  host_status_sender_.reset(new HostStatusSender(
      host_id_, signal_strategy_.get(), key_pair_, directory_bot_jid_));

  host_change_notification_listener_.reset(new HostChangeNotificationListener(
      this, host_id_, signal_strategy_.get(), directory_bot_jid_));

  log_to_server_.reset(
      new LogToServer(host_->AsWeakPtr(), ServerLogEntry::ME2ME,
                      signal_strategy_.get(), directory_bot_jid_));

  // Set up repoting the host status notifications.
#if defined(REMOTING_MULTI_PROCESS)
  host_event_logger_.reset(
      new IpcHostEventLogger(host_->AsWeakPtr(), daemon_channel_.get()));
#else  // !defined(REMOTING_MULTI_PROCESS)
  host_event_logger_ =
      HostEventLogger::Create(host_->AsWeakPtr(), kApplicationName);
#endif  // !defined(REMOTING_MULTI_PROCESS)

  host_->SetEnableCurtaining(curtain_required_);
  host_->Start(host_owner_);

  CreateAuthenticatorFactory();
}

void HostProcess::OnAuthFailed() {
  ShutdownHost(kInvalidOauthCredentialsExitCode);
}

void HostProcess::RestartHost() {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());
  DCHECK_EQ(state_, HOST_STARTED);

  state_ = HOST_STOPPING_TO_RESTART;
  ShutdownOnNetworkThread();
}

void HostProcess::ShutdownHost(HostExitCodes exit_code) {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  *exit_code_out_ = exit_code;

  switch (state_) {
    case HOST_INITIALIZING:
      state_ = HOST_STOPPING;
      ShutdownOnNetworkThread();
      break;

    case HOST_STARTED:
      state_ = HOST_STOPPING;
      host_status_sender_->SendOfflineStatus(exit_code);
      ScheduleHostShutdown();
      break;

    case HOST_STOPPING_TO_RESTART:
      state_ = HOST_STOPPING;
      break;

    case HOST_STOPPING:
    case HOST_STOPPED:
      // Host is already stopped or being stopped. No action is required.
      break;
  }
}

// TODO(weitaosu): shut down the host once we get an ACK for the offline status
//                  XMPP message.
void HostProcess::ScheduleHostShutdown() {
  // Delay the shutdown by 2 second to allow SendOfflineStatus to complete.
  context_->network_task_runner()->PostDelayedTask(
      FROM_HERE,
      base::Bind(&HostProcess::ShutdownOnNetworkThread, base::Unretained(this)),
      base::TimeDelta::FromSeconds(2));
}

void HostProcess::ShutdownOnNetworkThread() {
  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());

  host_.reset();
  host_event_logger_.reset();
  log_to_server_.reset();
  heartbeat_sender_.reset();
  host_status_sender_.reset();
  host_change_notification_listener_.reset();
  signaling_connector_.reset();
  oauth_token_getter_.reset();
  signal_strategy_.reset();
  network_change_notifier_.reset();

  if (state_ == HOST_STOPPING_TO_RESTART) {
    StartHost();
  } else if (state_ == HOST_STOPPING) {
    state_ = HOST_STOPPED;

    if (policy_watcher_.get()) {
      base::WaitableEvent done_event(true, false);
      policy_watcher_->StopWatching(&done_event);
      done_event.Wait();
      policy_watcher_.reset();
    }

    config_watcher_.reset();

    // Complete the rest of shutdown on the main thread.
    context_->ui_task_runner()->PostTask(
        FROM_HERE,
        base::Bind(&HostProcess::ShutdownOnUiThread, this));
  } else {
    // This method is only called in STOPPING_TO_RESTART and STOPPING states.
    NOTREACHED();
  }
}

void HostProcess::OnCrash(const std::string& function_name,
                          const std::string& file_name,
                          const int& line_number) {
  char message[1024];
  base::snprintf(message, sizeof(message),
                 "Requested by %s at %s, line %d.",
                 function_name.c_str(), file_name.c_str(), line_number);
  base::debug::Alias(message);

  // The daemon requested us to crash the process.
  CHECK(false) << message;
}

int HostProcessMain() {
#if defined(TOOLKIT_GTK)
  // Required for any calls into GTK functions, such as the Disconnect and
  // Continue windows, though these should not be used for the Me2Me case
  // (crbug.com/104377).
  gfx::GtkInitFromCommandLine(*CommandLine::ForCurrentProcess());
#endif  // TOOLKIT_GTK

  // Enable support for SSL server sockets, which must be done while still
  // single-threaded.
  net::EnableSSLServerSockets();

  // Ensures runtime specific CPU features are initialized.
  media::InitializeCPUSpecificMediaFeatures();

  // Create the main message loop and start helper threads.
  base::MessageLoopForUI message_loop;
  scoped_ptr<ChromotingHostContext> context =
      ChromotingHostContext::Create(new AutoThreadTaskRunner(
          message_loop.message_loop_proxy(), base::MessageLoop::QuitClosure()));
  if (!context)
    return kInitializationFailed;

  // Create & start the HostProcess using these threads.
  // TODO(wez): The HostProcess holds a reference to itself until Shutdown().
  // Remove this hack as part of the multi-process refactoring.
  int exit_code = kSuccessExitCode;
  new HostProcess(context.Pass(), &exit_code);

  // Run the main (also UI) message loop until the host no longer needs it.
  message_loop.Run();

  return exit_code;
}

}  // namespace remoting

#if !defined(OS_WIN)
int main(int argc, char** argv) {
  return remoting::HostMain(argc, argv);
}
#endif  // !defined(OS_WIN)
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root/remoting/host/remoting_me2me_host.cc

DEFINITIONS
