src/remoting/host/desktop_session_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "remoting/host/desktop_session_win.h"
   6
   7 #include <limits>
   8 #include <sddl.h>
   9
  10 #include "base/base_switches.h"
  11 #include "base/command_line.h"
  12 #include "base/files/file_path.h"
  13 #include "base/guid.h"
  14 #include "base/memory/ref_counted.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "base/memory/weak_ptr.h"
  17 #include "base/path_service.h"
  18 #include "base/strings/stringprintf.h"
  19 #include "base/strings/utf_string_conversions.h"
  20 #include "base/threading/thread_checker.h"
  21 #include "base/timer/timer.h"
  22 #include "base/win/scoped_bstr.h"
  23 #include "base/win/scoped_comptr.h"
  24 #include "base/win/scoped_handle.h"
  25 #include "base/win/windows_version.h"
  26 #include "ipc/ipc_message_macros.h"
  27 #include "ipc/ipc_platform_file.h"
  28 #include "remoting/base/auto_thread_task_runner.h"
  29 // MIDL-generated declarations and definitions.
  30 #include "remoting/host/chromoting_lib.h"
  31 #include "remoting/host/chromoting_messages.h"
  32 #include "remoting/host/daemon_process.h"
  33 #include "remoting/host/desktop_session.h"
  34 #include "remoting/host/host_main.h"
  35 #include "remoting/host/ipc_constants.h"
  36 #include "remoting/host/sas_injector.h"
  37 #include "remoting/host/screen_resolution.h"
  38 #include "remoting/host/win/host_service.h"
  39 #include "remoting/host/win/worker_process_launcher.h"
  40 #include "remoting/host/win/wts_session_process_delegate.h"
  41 #include "remoting/host/win/wts_terminal_monitor.h"
  42 #include "remoting/host/win/wts_terminal_observer.h"
  43 #include "remoting/host/worker_process_ipc_delegate.h"
  44
  45 using base::win::ScopedHandle;
  46
  47 namespace remoting {
  48
  49 namespace {
  50
  51 // The security descriptor of the daemon IPC endpoint. It gives full access
  52 // to SYSTEM and denies access by anyone else.
  53 const wchar_t kDaemonIpcSecurityDescriptor[] =
  54     SDDL_OWNER L":" SDDL_LOCAL_SYSTEM
  55     SDDL_GROUP L":" SDDL_LOCAL_SYSTEM
  56     SDDL_DACL L":("
  57         SDDL_ACCESS_ALLOWED L";;" SDDL_GENERIC_ALL L";;;" SDDL_LOCAL_SYSTEM
  58     L")";
  59
  60 // The command line parameters that should be copied from the service's command
  61 // line to the desktop process.
  62 const char* kCopiedSwitchNames[] = { switches::kV, switches::kVModule };
  63
  64 // The default screen dimensions for an RDP session.
  65 const int kDefaultRdpScreenWidth = 1280;
  66 const int kDefaultRdpScreenHeight = 768;
  67
  68 // RDC 6.1 (W2K8) supports dimensions of up to 4096x2048.
  69 const int kMaxRdpScreenWidth = 4096;
  70 const int kMaxRdpScreenHeight = 2048;
  71
  72 // The minimum effective screen dimensions supported by Windows are 800x600.
  73 const int kMinRdpScreenWidth = 800;
  74 const int kMinRdpScreenHeight = 600;
  75
  76 // Default dots per inch used by RDP is 96 DPI.
  77 const int kDefaultRdpDpi = 96;
  78
  79 // The session attach notification should arrive within 30 seconds.
  80 const int kSessionAttachTimeoutSeconds = 30;
  81
  82 // DesktopSession implementation which attaches to the host's physical console.
  83 // Receives IPC messages from the desktop process, running in the console
  84 // session, via |WorkerProcessIpcDelegate|, and monitors console session
  85 // attach/detach events via |WtsConsoleObserer|.
  86 class ConsoleSession : public DesktopSessionWin {
  87  public:
  88   // Same as DesktopSessionWin().
  89   ConsoleSession(
  90     scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
  91     scoped_refptr<AutoThreadTaskRunner> io_task_runner,
  92     DaemonProcess* daemon_process,
  93     int id,
  94     WtsTerminalMonitor* monitor);
  95   virtual ~ConsoleSession();
  96
  97  protected:
  98   // DesktopSession overrides.
  99   virtual void SetScreenResolution(const ScreenResolution& resolution) OVERRIDE;
 100
 101   // DesktopSessionWin overrides.
 102   virtual void InjectSas() OVERRIDE;
 103
 104  private:
 105   scoped_ptr<SasInjector> sas_injector_;
 106
 107   DISALLOW_COPY_AND_ASSIGN(ConsoleSession);
 108 };
 109
 110 // DesktopSession implementation which attaches to virtual RDP console.
 111 // Receives IPC messages from the desktop process, running in the console
 112 // session, via |WorkerProcessIpcDelegate|, and monitors console session
 113 // attach/detach events via |WtsConsoleObserer|.
 114 class RdpSession : public DesktopSessionWin {
 115  public:
 116   // Same as DesktopSessionWin().
 117   RdpSession(
 118     scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
 119     scoped_refptr<AutoThreadTaskRunner> io_task_runner,
 120     DaemonProcess* daemon_process,
 121     int id,
 122     WtsTerminalMonitor* monitor);
 123   virtual ~RdpSession();
 124
 125   // Performs the part of initialization that can fail.
 126   bool Initialize(const ScreenResolution& resolution);
 127
 128   // Mirrors IRdpDesktopSessionEventHandler.
 129   void OnRdpConnected();
 130   void OnRdpClosed();
 131
 132  protected:
 133   // DesktopSession overrides.
 134   virtual void SetScreenResolution(const ScreenResolution& resolution) OVERRIDE;
 135
 136   // DesktopSessionWin overrides.
 137   virtual void InjectSas() OVERRIDE;
 138
 139  private:
 140   // An implementation of IRdpDesktopSessionEventHandler interface that forwards
 141   // notifications to the owning desktop session.
 142   class EventHandler : public IRdpDesktopSessionEventHandler {
 143    public:
 144     explicit EventHandler(base::WeakPtr<RdpSession> desktop_session);
 145     virtual ~EventHandler();
 146
 147     // IUnknown interface.
 148     STDMETHOD_(ULONG, AddRef)() OVERRIDE;
 149     STDMETHOD_(ULONG, Release)() OVERRIDE;
 150     STDMETHOD(QueryInterface)(REFIID riid, void** ppv) OVERRIDE;
 151
 152     // IRdpDesktopSessionEventHandler interface.
 153     STDMETHOD(OnRdpConnected)() OVERRIDE;
 154     STDMETHOD(OnRdpClosed)() OVERRIDE;
 155
 156    private:
 157     ULONG ref_count_;
 158
 159     // Points to the desktop session object receiving OnRdpXxx() notifications.
 160     base::WeakPtr<RdpSession> desktop_session_;
 161
 162     // This class must be used on a single thread.
 163     base::ThreadChecker thread_checker_;
 164
 165     DISALLOW_COPY_AND_ASSIGN(EventHandler);
 166   };
 167
 168   // Used to create an RDP desktop session.
 169   base::win::ScopedComPtr<IRdpDesktopSession> rdp_desktop_session_;
 170
 171   // Used to match |rdp_desktop_session_| with the session it is attached to.
 172   std::string terminal_id_;
 173
 174   base::WeakPtrFactory<RdpSession> weak_factory_;
 175
 176   DISALLOW_COPY_AND_ASSIGN(RdpSession);
 177 };
 178
 179 ConsoleSession::ConsoleSession(
 180     scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
 181     scoped_refptr<AutoThreadTaskRunner> io_task_runner,
 182     DaemonProcess* daemon_process,
 183     int id,
 184     WtsTerminalMonitor* monitor)
 185     : DesktopSessionWin(caller_task_runner, io_task_runner, daemon_process, id,
 186                         monitor) {
 187   StartMonitoring(WtsTerminalMonitor::kConsole);
 188 }
 189
 190 ConsoleSession::~ConsoleSession() {
 191 }
 192
 193 void ConsoleSession::SetScreenResolution(const ScreenResolution& resolution) {
 194   // Do nothing. The screen resolution of the console session is controlled by
 195   // the DesktopSessionAgent instance running in that session.
 196   DCHECK(caller_task_runner()->BelongsToCurrentThread());
 197 }
 198
 199 void ConsoleSession::InjectSas() {
 200   DCHECK(caller_task_runner()->BelongsToCurrentThread());
 201
 202   if (!sas_injector_)
 203     sas_injector_ = SasInjector::Create();
 204   if (!sas_injector_->InjectSas())
 205     LOG(ERROR) << "Failed to inject Secure Attention Sequence.";
 206 }
 207
 208 RdpSession::RdpSession(
 209     scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
 210     scoped_refptr<AutoThreadTaskRunner> io_task_runner,
 211     DaemonProcess* daemon_process,
 212     int id,
 213     WtsTerminalMonitor* monitor)
 214     : DesktopSessionWin(caller_task_runner, io_task_runner, daemon_process, id,
 215                         monitor),
 216       weak_factory_(this) {
 217 }
 218
 219 RdpSession::~RdpSession() {
 220 }
 221
 222 bool RdpSession::Initialize(const ScreenResolution& resolution) {
 223   DCHECK(caller_task_runner()->BelongsToCurrentThread());
 224
 225   // Create the RDP wrapper object.
 226   HRESULT result = rdp_desktop_session_.CreateInstance(
 227       __uuidof(RdpDesktopSession));
 228   if (FAILED(result)) {
 229     LOG(ERROR) << "Failed to create RdpSession object, 0x"
 230                << std::hex << result << std::dec << ".";
 231     return false;
 232   }
 233
 234   ScreenResolution local_resolution = resolution;
 235
 236   // If the screen resolution is not specified, use the default screen
 237   // resolution.
 238   if (local_resolution.IsEmpty()) {
 239     local_resolution = ScreenResolution(
 240         webrtc::DesktopSize(kDefaultRdpScreenWidth, kDefaultRdpScreenHeight),
 241         webrtc::DesktopVector(kDefaultRdpDpi, kDefaultRdpDpi));
 242   }
 243
 244   // Get the screen dimensions assuming the default DPI.
 245   webrtc::DesktopSize host_size = local_resolution.ScaleDimensionsToDpi(
 246       webrtc::DesktopVector(kDefaultRdpDpi, kDefaultRdpDpi));
 247
 248   // Make sure that the host resolution is within the limits supported by RDP.
 249   host_size = webrtc::DesktopSize(
 250       std::min(kMaxRdpScreenWidth,
 251                std::max(kMinRdpScreenWidth, host_size.width())),
 252       std::min(kMaxRdpScreenHeight,
 253                std::max(kMinRdpScreenHeight, host_size.height())));
 254
 255   // Create an RDP session.
 256   base::win::ScopedComPtr<IRdpDesktopSessionEventHandler> event_handler(
 257       new EventHandler(weak_factory_.GetWeakPtr()));
 258   terminal_id_ = base::GenerateGUID();
 259   base::win::ScopedBstr terminal_id(base::UTF8ToUTF16(terminal_id_).c_str());
 260   result = rdp_desktop_session_->Connect(host_size.width(),
 261                                          host_size.height(),
 262                                          terminal_id,
 263                                          event_handler);
 264   if (FAILED(result)) {
 265     LOG(ERROR) << "RdpSession::Create() failed, 0x"
 266                << std::hex << result << std::dec << ".";
 267     return false;
 268   }
 269
 270   return true;
 271 }
 272
 273 void RdpSession::OnRdpConnected() {
 274   DCHECK(caller_task_runner()->BelongsToCurrentThread());
 275
 276   StopMonitoring();
 277   StartMonitoring(terminal_id_);
 278 }
 279
 280 void RdpSession::OnRdpClosed() {
 281   DCHECK(caller_task_runner()->BelongsToCurrentThread());
 282
 283   TerminateSession();
 284 }
 285
 286 void RdpSession::SetScreenResolution(const ScreenResolution& resolution) {
 287   DCHECK(caller_task_runner()->BelongsToCurrentThread());
 288
 289   // TODO(alexeypa): implement resize-to-client for RDP sessions here.
 290   // See http://crbug.com/137696.
 291   NOTIMPLEMENTED();
 292 }
 293
 294 void RdpSession::InjectSas() {
 295   DCHECK(caller_task_runner()->BelongsToCurrentThread());
 296
 297   rdp_desktop_session_->InjectSas();
 298 }
 299
 300 RdpSession::EventHandler::EventHandler(
 301     base::WeakPtr<RdpSession> desktop_session)
 302     : ref_count_(0),
 303       desktop_session_(desktop_session) {
 304 }
 305
 306 RdpSession::EventHandler::~EventHandler() {
 307   DCHECK(thread_checker_.CalledOnValidThread());
 308
 309   if (desktop_session_)
 310     desktop_session_->OnRdpClosed();
 311 }
 312
 313 ULONG STDMETHODCALLTYPE RdpSession::EventHandler::AddRef() {
 314   DCHECK(thread_checker_.CalledOnValidThread());
 315
 316   return ++ref_count_;
 317 }
 318
 319 ULONG STDMETHODCALLTYPE RdpSession::EventHandler::Release() {
 320   DCHECK(thread_checker_.CalledOnValidThread());
 321
 322   if (--ref_count_ == 0) {
 323     delete this;
 324     return 0;
 325   }
 326
 327   return ref_count_;
 328 }
 329
 330 STDMETHODIMP RdpSession::EventHandler::QueryInterface(REFIID riid, void** ppv) {
 331   DCHECK(thread_checker_.CalledOnValidThread());
 332
 333   if (riid == IID_IUnknown ||
 334       riid == IID_IRdpDesktopSessionEventHandler) {
 335     *ppv = static_cast<IRdpDesktopSessionEventHandler*>(this);
 336     AddRef();
 337     return S_OK;
 338   }
 339
 340   *ppv = NULL;
 341   return E_NOINTERFACE;
 342 }
 343
 344 STDMETHODIMP RdpSession::EventHandler::OnRdpConnected() {
 345   DCHECK(thread_checker_.CalledOnValidThread());
 346
 347   if (desktop_session_)
 348     desktop_session_->OnRdpConnected();
 349
 350   return S_OK;
 351 }
 352
 353 STDMETHODIMP RdpSession::EventHandler::OnRdpClosed() {
 354   DCHECK(thread_checker_.CalledOnValidThread());
 355
 356   if (!desktop_session_)
 357     return S_OK;
 358
 359   base::WeakPtr<RdpSession> desktop_session = desktop_session_;
 360   desktop_session_.reset();
 361   desktop_session->OnRdpClosed();
 362   return S_OK;
 363 }
 364
 365 } // namespace
 366
 367 // static
 368 scoped_ptr<DesktopSession> DesktopSessionWin::CreateForConsole(
 369     scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
 370     scoped_refptr<AutoThreadTaskRunner> io_task_runner,
 371     DaemonProcess* daemon_process,
 372     int id,
 373     const ScreenResolution& resolution) {
 374   scoped_ptr<ConsoleSession> session(new ConsoleSession(
 375       caller_task_runner, io_task_runner, daemon_process, id,
 376       HostService::GetInstance()));
 377
 378   return session.PassAs<DesktopSession>();
 379 }
 380
 381 // static
 382 scoped_ptr<DesktopSession> DesktopSessionWin::CreateForVirtualTerminal(
 383     scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
 384     scoped_refptr<AutoThreadTaskRunner> io_task_runner,
 385     DaemonProcess* daemon_process,
 386     int id,
 387     const ScreenResolution& resolution) {
 388   scoped_ptr<RdpSession> session(new RdpSession(
 389       caller_task_runner, io_task_runner, daemon_process, id,
 390       HostService::GetInstance()));
 391   if (!session->Initialize(resolution))
 392     return scoped_ptr<DesktopSession>();
 393
 394   return session.PassAs<DesktopSession>();
 395 }
 396
 397 DesktopSessionWin::DesktopSessionWin(
 398     scoped_refptr<AutoThreadTaskRunner> caller_task_runner,
 399     scoped_refptr<AutoThreadTaskRunner> io_task_runner,
 400     DaemonProcess* daemon_process,
 401     int id,
 402     WtsTerminalMonitor* monitor)
 403     : DesktopSession(daemon_process, id),
 404       caller_task_runner_(caller_task_runner),
 405       io_task_runner_(io_task_runner),
 406       monitor_(monitor),
 407       monitoring_notifications_(false) {
 408   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 409
 410   ReportElapsedTime("created");
 411 }
 412
 413 DesktopSessionWin::~DesktopSessionWin() {
 414   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 415
 416   StopMonitoring();
 417 }
 418
 419 void DesktopSessionWin::OnSessionAttachTimeout() {
 420   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 421
 422   LOG(ERROR) << "Session attach notification didn't arrived within "
 423              << kSessionAttachTimeoutSeconds << " seconds.";
 424   TerminateSession();
 425 }
 426
 427 void DesktopSessionWin::StartMonitoring(const std::string& terminal_id) {
 428   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 429   DCHECK(!monitoring_notifications_);
 430   DCHECK(!session_attach_timer_.IsRunning());
 431
 432   ReportElapsedTime("started monitoring");
 433
 434   session_attach_timer_.Start(
 435       FROM_HERE, base::TimeDelta::FromSeconds(kSessionAttachTimeoutSeconds),
 436       this, &DesktopSessionWin::OnSessionAttachTimeout);
 437
 438   monitoring_notifications_ = true;
 439   monitor_->AddWtsTerminalObserver(terminal_id, this);
 440 }
 441
 442 void DesktopSessionWin::StopMonitoring() {
 443   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 444
 445   if (monitoring_notifications_) {
 446     ReportElapsedTime("stopped monitoring");
 447
 448     monitoring_notifications_ = false;
 449     monitor_->RemoveWtsTerminalObserver(this);
 450   }
 451
 452   session_attach_timer_.Stop();
 453   OnSessionDetached();
 454 }
 455
 456 void DesktopSessionWin::TerminateSession() {
 457   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 458
 459   StopMonitoring();
 460
 461   // This call will delete |this| so it should be at the very end of the method.
 462   daemon_process()->CloseDesktopSession(id());
 463 }
 464
 465 void DesktopSessionWin::OnChannelConnected(int32 peer_pid) {
 466   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 467
 468   ReportElapsedTime("channel connected");
 469
 470   // Obtain the handle of the desktop process. It will be passed to the network
 471   // process to use to duplicate handles of shared memory objects from
 472   // the desktop process.
 473   desktop_process_.Set(OpenProcess(PROCESS_DUP_HANDLE, false, peer_pid));
 474   if (!desktop_process_.IsValid()) {
 475     CrashDesktopProcess(FROM_HERE);
 476     return;
 477   }
 478
 479   VLOG(1) << "IPC: daemon <- desktop (" << peer_pid << ")";
 480 }
 481
 482 bool DesktopSessionWin::OnMessageReceived(const IPC::Message& message) {
 483   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 484
 485   bool handled = true;
 486   IPC_BEGIN_MESSAGE_MAP(DesktopSessionWin, message)
 487     IPC_MESSAGE_HANDLER(ChromotingDesktopDaemonMsg_DesktopAttached,
 488                         OnDesktopSessionAgentAttached)
 489     IPC_MESSAGE_HANDLER(ChromotingDesktopDaemonMsg_InjectSas,
 490                         InjectSas)
 491     IPC_MESSAGE_UNHANDLED(handled = false)
 492   IPC_END_MESSAGE_MAP()
 493
 494   if (!handled) {
 495     LOG(ERROR) << "Received unexpected IPC type: " << message.type();
 496     CrashDesktopProcess(FROM_HERE);
 497   }
 498
 499   return handled;
 500 }
 501
 502 void DesktopSessionWin::OnPermanentError(int exit_code) {
 503   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 504
 505   TerminateSession();
 506 }
 507
 508 void DesktopSessionWin::OnSessionAttached(uint32 session_id) {
 509   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 510   DCHECK(!launcher_);
 511   DCHECK(monitoring_notifications_);
 512
 513   ReportElapsedTime("attached");
 514
 515   // Launch elevated on Win8 to be able to inject Alt+Tab.
 516   bool launch_elevated = base::win::GetVersion() >= base::win::VERSION_WIN8;
 517
 518   // Get the name of the executable to run. |kDesktopBinaryName| specifies
 519   // uiAccess="true" in it's manifest.
 520   base::FilePath desktop_binary;
 521   bool result;
 522   if (launch_elevated) {
 523     result = GetInstalledBinaryPath(kDesktopBinaryName, &desktop_binary);
 524   } else {
 525     result = GetInstalledBinaryPath(kHostBinaryName, &desktop_binary);
 526   }
 527
 528   if (!result) {
 529     TerminateSession();
 530     return;
 531   }
 532
 533   session_attach_timer_.Stop();
 534
 535   scoped_ptr<CommandLine> target(new CommandLine(desktop_binary));
 536   target->AppendSwitchASCII(kProcessTypeSwitchName, kProcessTypeDesktop);
 537   // Copy the command line switches enabling verbose logging.
 538   target->CopySwitchesFrom(*CommandLine::ForCurrentProcess(),
 539                            kCopiedSwitchNames,
 540                            arraysize(kCopiedSwitchNames));
 541
 542   // Create a delegate capable of launching a process in a different session.
 543   scoped_ptr<WtsSessionProcessDelegate> delegate(
 544       new WtsSessionProcessDelegate(io_task_runner_,
 545                                     target.Pass(),
 546                                     launch_elevated,
 547                                     base::WideToUTF8(
 548                                         kDaemonIpcSecurityDescriptor)));
 549   if (!delegate->Initialize(session_id)) {
 550     TerminateSession();
 551     return;
 552   }
 553
 554   // Create a launcher for the desktop process, using the per-session delegate.
 555   launcher_.reset(new WorkerProcessLauncher(
 556       delegate.PassAs<WorkerProcessLauncher::Delegate>(), this));
 557 }
 558
 559 void DesktopSessionWin::OnSessionDetached() {
 560   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 561
 562   launcher_.reset();
 563
 564   if (monitoring_notifications_) {
 565     ReportElapsedTime("detached");
 566
 567     session_attach_timer_.Start(
 568         FROM_HERE, base::TimeDelta::FromSeconds(kSessionAttachTimeoutSeconds),
 569         this, &DesktopSessionWin::OnSessionAttachTimeout);
 570   }
 571 }
 572
 573 void DesktopSessionWin::OnDesktopSessionAgentAttached(
 574       IPC::PlatformFileForTransit desktop_pipe) {
 575   if (!daemon_process()->OnDesktopSessionAgentAttached(id(),
 576                                                        desktop_process_,
 577                                                        desktop_pipe)) {
 578     CrashDesktopProcess(FROM_HERE);
 579   }
 580 }
 581
 582 void DesktopSessionWin::CrashDesktopProcess(
 583     const tracked_objects::Location& location) {
 584   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 585
 586   launcher_->Crash(location);
 587 }
 588
 589 void DesktopSessionWin::ReportElapsedTime(const std::string& event) {
 590   base::Time now = base::Time::Now();
 591
 592   std::string passed;
 593   if (!last_timestamp_.is_null()) {
 594     passed = base::StringPrintf(", %.2fs passed",
 595                                 (now - last_timestamp_).InSecondsF());
 596   }
 597
 598   base::Time::Exploded exploded;
 599   now.LocalExplode(&exploded);
 600   VLOG(1) << base::StringPrintf("session(%d): %s at %02d:%02d:%02d.%03d%s",
 601                                 id(),
 602                                 event.c_str(),
 603                                 exploded.hour,
 604                                 exploded.minute,
 605                                 exploded.second,
 606                                 exploded.millisecond,
 607                                 passed.c_str());
 608
 609   last_timestamp_ = now;
 610 }
 611
 612 }  // namespace remoting