content/child/child_thread_impl.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 "content/child/child_thread_impl.h"
   6
   7 #include <signal.h>
   8
   9 #include <string>
  10
  11 #include "base/allocator/allocator_extension.h"
  12 #include "base/base_switches.h"
  13 #include "base/basictypes.h"
  14 #include "base/command_line.h"
  15 #include "base/debug/leak_annotations.h"
  16 #include "base/lazy_instance.h"
  17 #include "base/logging.h"
  18 #include "base/message_loop/message_loop.h"
  19 #include "base/message_loop/timer_slack.h"
  20 #include "base/metrics/field_trial.h"
  21 #include "base/process/kill.h"
  22 #include "base/process/process_handle.h"
  23 #include "base/strings/string_number_conversions.h"
  24 #include "base/strings/string_util.h"
  25 #include "base/synchronization/condition_variable.h"
  26 #include "base/synchronization/lock.h"
  27 #include "base/threading/thread_local.h"
  28 #include "base/tracked_objects.h"
  29 #include "components/tracing/child_trace_message_filter.h"
  30 #include "content/child/bluetooth/bluetooth_message_filter.h"
  31 #include "content/child/child_discardable_shared_memory_manager.h"
  32 #include "content/child/child_gpu_memory_buffer_manager.h"
  33 #include "content/child/child_histogram_message_filter.h"
  34 #include "content/child/child_process.h"
  35 #include "content/child/child_resource_message_filter.h"
  36 #include "content/child/child_shared_bitmap_manager.h"
  37 #include "content/child/fileapi/file_system_dispatcher.h"
  38 #include "content/child/fileapi/webfilesystem_impl.h"
  39 #include "content/child/geofencing/geofencing_message_filter.h"
  40 #include "content/child/mojo/mojo_application.h"
  41 #include "content/child/navigator_connect/navigator_connect_dispatcher.h"
  42 #include "content/child/notifications/notification_dispatcher.h"
  43 #include "content/child/power_monitor_broadcast_source.h"
  44 #include "content/child/push_messaging/push_dispatcher.h"
  45 #include "content/child/quota_dispatcher.h"
  46 #include "content/child/quota_message_filter.h"
  47 #include "content/child/resource_dispatcher.h"
  48 #include "content/child/service_worker/service_worker_message_filter.h"
  49 #include "content/child/thread_safe_sender.h"
  50 #include "content/child/websocket_dispatcher.h"
  51 #include "content/common/child_process_messages.h"
  52 #include "content/common/mojo/channel_init.h"
  53 #include "content/public/common/content_switches.h"
  54 #include "ipc/ipc_logging.h"
  55 #include "ipc/ipc_switches.h"
  56 #include "ipc/ipc_sync_channel.h"
  57 #include "ipc/ipc_sync_message_filter.h"
  58 #include "ipc/mojo/ipc_channel_mojo.h"
  59 #include "ipc/mojo/scoped_ipc_support.h"
  60
  61 #if defined(OS_WIN)
  62 #include "content/common/handle_enumerator_win.h"
  63 #endif
  64
  65 #if defined(TCMALLOC_TRACE_MEMORY_SUPPORTED)
  66 #include "third_party/tcmalloc/chromium/src/gperftools/heap-profiler.h"
  67 #endif
  68
  69 using tracked_objects::ThreadData;
  70
  71 namespace content {
  72 namespace {
  73
  74 // How long to wait for a connection to the browser process before giving up.
  75 const int kConnectionTimeoutS = 15;
  76
  77 base::LazyInstance<base::ThreadLocalPointer<ChildThreadImpl> > g_lazy_tls =
  78     LAZY_INSTANCE_INITIALIZER;
  79
  80 // This isn't needed on Windows because there the sandbox's job object
  81 // terminates child processes automatically. For unsandboxed processes (i.e.
  82 // plugins), PluginThread has EnsureTerminateMessageFilter.
  83 #if defined(OS_POSIX)
  84
  85 #if defined(ADDRESS_SANITIZER) || defined(LEAK_SANITIZER) || \
  86     defined(MEMORY_SANITIZER) || defined(THREAD_SANITIZER) || \
  87     defined(UNDEFINED_SANITIZER)
  88 // A thread delegate that waits for |duration| and then exits the process with
  89 // _exit(0).
  90 class WaitAndExitDelegate : public base::PlatformThread::Delegate {
  91  public:
  92   explicit WaitAndExitDelegate(base::TimeDelta duration)
  93       : duration_(duration) {}
  94
  95   void ThreadMain() override {
  96     base::PlatformThread::Sleep(duration_);
  97     _exit(0);
  98   }
  99
 100  private:
 101   const base::TimeDelta duration_;
 102   DISALLOW_COPY_AND_ASSIGN(WaitAndExitDelegate);
 103 };
 104
 105 bool CreateWaitAndExitThread(base::TimeDelta duration) {
 106   scoped_ptr<WaitAndExitDelegate> delegate(new WaitAndExitDelegate(duration));
 107
 108   const bool thread_created =
 109       base::PlatformThread::CreateNonJoinable(0, delegate.get());
 110   if (!thread_created)
 111     return false;
 112
 113   // A non joinable thread has been created. The thread will either terminate
 114   // the process or will be terminated by the process. Therefore, keep the
 115   // delegate object alive for the lifetime of the process.
 116   WaitAndExitDelegate* leaking_delegate = delegate.release();
 117   ANNOTATE_LEAKING_OBJECT_PTR(leaking_delegate);
 118   ignore_result(leaking_delegate);
 119   return true;
 120 }
 121 #endif
 122
 123 class SuicideOnChannelErrorFilter : public IPC::MessageFilter {
 124  public:
 125   // IPC::MessageFilter
 126   void OnChannelError() override {
 127     // For renderer/worker processes:
 128     // On POSIX, at least, one can install an unload handler which loops
 129     // forever and leave behind a renderer process which eats 100% CPU forever.
 130     //
 131     // This is because the terminate signals (ViewMsg_ShouldClose and the error
 132     // from the IPC sender) are routed to the main message loop but never
 133     // processed (because that message loop is stuck in V8).
 134     //
 135     // One could make the browser SIGKILL the renderers, but that leaves open a
 136     // large window where a browser failure (or a user, manually terminating
 137     // the browser because "it's stuck") will leave behind a process eating all
 138     // the CPU.
 139     //
 140     // So, we install a filter on the sender so that we can process this event
 141     // here and kill the process.
 142 #if defined(ADDRESS_SANITIZER) || defined(LEAK_SANITIZER) || \
 143     defined(MEMORY_SANITIZER) || defined(THREAD_SANITIZER) || \
 144     defined(UNDEFINED_SANITIZER)
 145     // Some sanitizer tools rely on exit handlers (e.g. to run leak detection,
 146     // or dump code coverage data to disk). Instead of exiting the process
 147     // immediately, we give it 60 seconds to run exit handlers.
 148     CHECK(CreateWaitAndExitThread(base::TimeDelta::FromSeconds(60)));
 149 #if defined(LEAK_SANITIZER)
 150     // Invoke LeakSanitizer early to avoid detecting shutdown-only leaks. If
 151     // leaks are found, the process will exit here.
 152     __lsan_do_leak_check();
 153 #endif
 154 #else
 155     _exit(0);
 156 #endif
 157   }
 158
 159  protected:
 160   ~SuicideOnChannelErrorFilter() override {}
 161 };
 162
 163 #endif  // OS(POSIX)
 164
 165 #if defined(OS_ANDROID)
 166 ChildThreadImpl* g_child_thread = NULL;
 167 bool g_child_thread_initialized = false;
 168
 169 // A lock protects g_child_thread.
 170 base::LazyInstance<base::Lock>::Leaky g_lazy_child_thread_lock =
 171     LAZY_INSTANCE_INITIALIZER;
 172
 173 // base::ConditionVariable has an explicit constructor that takes
 174 // a base::Lock pointer as parameter. The base::DefaultLazyInstanceTraits
 175 // doesn't handle the case. Thus, we need our own class here.
 176 struct CondVarLazyInstanceTraits {
 177   static const bool kRegisterOnExit = false;
 178 #ifndef NDEBUG
 179   static const bool kAllowedToAccessOnNonjoinableThread = true;
 180 #endif
 181
 182   static base::ConditionVariable* New(void* instance) {
 183     return new (instance) base::ConditionVariable(
 184         g_lazy_child_thread_lock.Pointer());
 185   }
 186   static void Delete(base::ConditionVariable* instance) {
 187     instance->~ConditionVariable();
 188   }
 189 };
 190
 191 // A condition variable that synchronize threads initializing and waiting
 192 // for g_child_thread.
 193 base::LazyInstance<base::ConditionVariable, CondVarLazyInstanceTraits>
 194     g_lazy_child_thread_cv = LAZY_INSTANCE_INITIALIZER;
 195
 196 void QuitMainThreadMessageLoop() {
 197   base::MessageLoop::current()->Quit();
 198 }
 199
 200 #endif
 201
 202 }  // namespace
 203
 204 ChildThread* ChildThread::Get() {
 205   return ChildThreadImpl::current();
 206 }
 207
 208 // Mojo client channel delegate to be used in single process mode.
 209 class ChildThreadImpl::SingleProcessChannelDelegate
 210     : public IPC::ChannelMojo::Delegate {
 211  public:
 212   explicit SingleProcessChannelDelegate() : weak_factory_(this) {}
 213
 214   ~SingleProcessChannelDelegate() override {}
 215
 216   base::WeakPtr<IPC::ChannelMojo::Delegate> ToWeakPtr() override {
 217     return weak_factory_.GetWeakPtr();
 218   }
 219
 220   scoped_refptr<base::TaskRunner> GetIOTaskRunner() override {
 221     return ChannelInit::GetSingleProcessIOTaskRunner();
 222   }
 223
 224   void OnChannelCreated(base::WeakPtr<IPC::ChannelMojo> channel) override {}
 225
 226   void DeleteSoon() {
 227     ChannelInit::GetSingleProcessIOTaskRunner()->PostTask(
 228         FROM_HERE,
 229         base::Bind(&base::DeletePointer<SingleProcessChannelDelegate>,
 230                    base::Unretained(this)));
 231   }
 232
 233  private:
 234   base::WeakPtrFactory<IPC::ChannelMojo::Delegate> weak_factory_;
 235
 236   DISALLOW_COPY_AND_ASSIGN(SingleProcessChannelDelegate);
 237 };
 238
 239 void ChildThreadImpl::SingleProcessChannelDelegateDeleter::operator()(
 240     SingleProcessChannelDelegate* delegate) const {
 241   delegate->DeleteSoon();
 242 }
 243
 244 ChildThreadImpl::Options::Options()
 245     : channel_name(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
 246           switches::kProcessChannelID)),
 247       use_mojo_channel(false),
 248       in_browser_process(false) {
 249 }
 250
 251 ChildThreadImpl::Options::Options(bool mojo)
 252     : channel_name(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
 253           switches::kProcessChannelID)),
 254       use_mojo_channel(mojo),
 255       in_browser_process(true) {
 256 }
 257
 258 ChildThreadImpl::Options::Options(std::string name, bool mojo)
 259     : channel_name(name), use_mojo_channel(mojo), in_browser_process(true) {
 260 }
 261
 262 ChildThreadImpl::Options::~Options() {
 263 }
 264
 265 ChildThreadImpl::ChildThreadMessageRouter::ChildThreadMessageRouter(
 266     IPC::Sender* sender)
 267     : sender_(sender) {}
 268
 269 bool ChildThreadImpl::ChildThreadMessageRouter::Send(IPC::Message* msg) {
 270   return sender_->Send(msg);
 271 }
 272
 273 ChildThreadImpl::ChildThreadImpl()
 274     : router_(this),
 275       in_browser_process_(false),
 276       channel_connected_factory_(this) {
 277   Init(Options());
 278 }
 279
 280 ChildThreadImpl::ChildThreadImpl(const Options& options)
 281     : router_(this),
 282       in_browser_process_(options.in_browser_process),
 283       channel_connected_factory_(this) {
 284   Init(options);
 285 }
 286
 287 void ChildThreadImpl::ConnectChannel(bool use_mojo_channel) {
 288   bool create_pipe_now = true;
 289   if (use_mojo_channel) {
 290     VLOG(1) << "Mojo is enabled on child";
 291     scoped_refptr<base::TaskRunner> io_task_runner =
 292         ChannelInit::GetSingleProcessIOTaskRunner();
 293     if (io_task_runner) {
 294       single_process_channel_delegate_.reset(new SingleProcessChannelDelegate);
 295     } else {
 296       io_task_runner = ChildProcess::current()->io_message_loop_proxy();
 297     }
 298     DCHECK(io_task_runner);
 299     ipc_support_.reset(new IPC::ScopedIPCSupport(io_task_runner));
 300     channel_->Init(
 301         IPC::ChannelMojo::CreateClientFactory(
 302             single_process_channel_delegate_.get(),
 303             channel_name_),
 304         create_pipe_now);
 305     return;
 306   }
 307
 308   VLOG(1) << "Mojo is disabled on child";
 309   channel_->Init(channel_name_, IPC::Channel::MODE_CLIENT, create_pipe_now);
 310 }
 311
 312 void ChildThreadImpl::Init(const Options& options) {
 313   channel_name_ = options.channel_name;
 314
 315   g_lazy_tls.Pointer()->Set(this);
 316   on_channel_error_called_ = false;
 317   message_loop_ = base::MessageLoop::current();
 318 #ifdef IPC_MESSAGE_LOG_ENABLED
 319   // We must make sure to instantiate the IPC Logger *before* we create the
 320   // channel, otherwise we can get a callback on the IO thread which creates
 321   // the logger, and the logger does not like being created on the IO thread.
 322   IPC::Logging::GetInstance();
 323 #endif
 324   channel_ = IPC::SyncChannel::Create(
 325       this, ChildProcess::current()->io_message_loop_proxy(),
 326       ChildProcess::current()->GetShutDownEvent());
 327 #ifdef IPC_MESSAGE_LOG_ENABLED
 328   if (!in_browser_process_)
 329     IPC::Logging::GetInstance()->SetIPCSender(this);
 330 #endif
 331
 332   mojo_application_.reset(new MojoApplication);
 333
 334   sync_message_filter_ =
 335       new IPC::SyncMessageFilter(ChildProcess::current()->GetShutDownEvent());
 336   thread_safe_sender_ = new ThreadSafeSender(
 337       base::MessageLoopProxy::current().get(), sync_message_filter_.get());
 338
 339   resource_dispatcher_.reset(new ResourceDispatcher(
 340       this, message_loop()->task_runner()));
 341   websocket_dispatcher_.reset(new WebSocketDispatcher);
 342   file_system_dispatcher_.reset(new FileSystemDispatcher());
 343
 344   histogram_message_filter_ = new ChildHistogramMessageFilter();
 345   resource_message_filter_ =
 346       new ChildResourceMessageFilter(resource_dispatcher());
 347
 348   service_worker_message_filter_ =
 349       new ServiceWorkerMessageFilter(thread_safe_sender_.get());
 350
 351   quota_message_filter_ =
 352       new QuotaMessageFilter(thread_safe_sender_.get());
 353   quota_dispatcher_.reset(new QuotaDispatcher(thread_safe_sender_.get(),
 354                                               quota_message_filter_.get()));
 355   geofencing_message_filter_ =
 356       new GeofencingMessageFilter(thread_safe_sender_.get());
 357   bluetooth_message_filter_ =
 358       new BluetoothMessageFilter(thread_safe_sender_.get());
 359   notification_dispatcher_ =
 360       new NotificationDispatcher(thread_safe_sender_.get());
 361   push_dispatcher_ = new PushDispatcher(thread_safe_sender_.get());
 362   navigator_connect_dispatcher_ =
 363       new NavigatorConnectDispatcher(thread_safe_sender_.get());
 364
 365   channel_->AddFilter(histogram_message_filter_.get());
 366   channel_->AddFilter(sync_message_filter_.get());
 367   channel_->AddFilter(resource_message_filter_.get());
 368   channel_->AddFilter(quota_message_filter_->GetFilter());
 369   channel_->AddFilter(notification_dispatcher_->GetFilter());
 370   channel_->AddFilter(push_dispatcher_->GetFilter());
 371   channel_->AddFilter(service_worker_message_filter_->GetFilter());
 372   channel_->AddFilter(geofencing_message_filter_->GetFilter());
 373   channel_->AddFilter(bluetooth_message_filter_->GetFilter());
 374   channel_->AddFilter(navigator_connect_dispatcher_->GetFilter());
 375
 376   if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
 377           switches::kSingleProcess)) {
 378     // In single process mode, browser-side tracing will cover the whole
 379     // process including renderers.
 380     channel_->AddFilter(new tracing::ChildTraceMessageFilter(
 381         ChildProcess::current()->io_message_loop_proxy()));
 382   }
 383
 384   // In single process mode we may already have a power monitor
 385   if (!base::PowerMonitor::Get()) {
 386     scoped_ptr<PowerMonitorBroadcastSource> power_monitor_source(
 387       new PowerMonitorBroadcastSource());
 388     channel_->AddFilter(power_monitor_source->GetMessageFilter());
 389
 390     power_monitor_.reset(new base::PowerMonitor(
 391         power_monitor_source.Pass()));
 392   }
 393
 394 #if defined(OS_POSIX)
 395   // Check that --process-type is specified so we don't do this in unit tests
 396   // and single-process mode.
 397   if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kProcessType))
 398     channel_->AddFilter(new SuicideOnChannelErrorFilter());
 399 #endif
 400
 401   // Add filters passed here via options.
 402   for (auto startup_filter : options.startup_filters) {
 403     channel_->AddFilter(startup_filter);
 404   }
 405
 406   ConnectChannel(options.use_mojo_channel);
 407
 408   int connection_timeout = kConnectionTimeoutS;
 409   std::string connection_override =
 410       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
 411           switches::kIPCConnectionTimeout);
 412   if (!connection_override.empty()) {
 413     int temp;
 414     if (base::StringToInt(connection_override, &temp))
 415       connection_timeout = temp;
 416   }
 417
 418   base::MessageLoop::current()->PostDelayedTask(
 419       FROM_HERE,
 420       base::Bind(&ChildThreadImpl::EnsureConnected,
 421                  channel_connected_factory_.GetWeakPtr()),
 422       base::TimeDelta::FromSeconds(connection_timeout));
 423
 424 #if defined(OS_ANDROID)
 425   {
 426     base::AutoLock lock(g_lazy_child_thread_lock.Get());
 427     g_child_thread = this;
 428     g_child_thread_initialized = true;
 429   }
 430   // Signalling without locking is fine here because only
 431   // one thread can wait on the condition variable.
 432   g_lazy_child_thread_cv.Get().Signal();
 433 #endif
 434
 435 #if defined(TCMALLOC_TRACE_MEMORY_SUPPORTED)
 436   trace_memory_controller_.reset(new base::trace_event::TraceMemoryController(
 437       message_loop_->message_loop_proxy(), ::HeapProfilerWithPseudoStackStart,
 438       ::HeapProfilerStop, ::GetHeapProfile));
 439 #endif
 440
 441   shared_bitmap_manager_.reset(
 442       new ChildSharedBitmapManager(thread_safe_sender()));
 443
 444   gpu_memory_buffer_manager_.reset(
 445       new ChildGpuMemoryBufferManager(thread_safe_sender()));
 446
 447   discardable_shared_memory_manager_.reset(
 448       new ChildDiscardableSharedMemoryManager(thread_safe_sender()));
 449 }
 450
 451 ChildThreadImpl::~ChildThreadImpl() {
 452 #if defined(OS_ANDROID)
 453   {
 454     base::AutoLock lock(g_lazy_child_thread_lock.Get());
 455     g_child_thread = nullptr;
 456   }
 457 #endif
 458
 459 #ifdef IPC_MESSAGE_LOG_ENABLED
 460   IPC::Logging::GetInstance()->SetIPCSender(NULL);
 461 #endif
 462
 463   channel_->RemoveFilter(histogram_message_filter_.get());
 464   channel_->RemoveFilter(sync_message_filter_.get());
 465
 466   // The ChannelProxy object caches a pointer to the IPC thread, so need to
 467   // reset it as it's not guaranteed to outlive this object.
 468   // NOTE: this also has the side-effect of not closing the main IPC channel to
 469   // the browser process.  This is needed because this is the signal that the
 470   // browser uses to know that this process has died, so we need it to be alive
 471   // until this process is shut down, and the OS closes the handle
 472   // automatically.  We used to watch the object handle on Windows to do this,
 473   // but it wasn't possible to do so on POSIX.
 474   channel_->ClearIPCTaskRunner();
 475   g_lazy_tls.Pointer()->Set(NULL);
 476 }
 477
 478 void ChildThreadImpl::Shutdown() {
 479   // Delete objects that hold references to blink so derived classes can
 480   // safely shutdown blink in their Shutdown implementation.
 481   file_system_dispatcher_.reset();
 482   quota_dispatcher_.reset();
 483   WebFileSystemImpl::DeleteThreadSpecificInstance();
 484 }
 485
 486 void ChildThreadImpl::OnChannelConnected(int32 peer_pid) {
 487   channel_connected_factory_.InvalidateWeakPtrs();
 488 }
 489
 490 void ChildThreadImpl::OnChannelError() {
 491   set_on_channel_error_called(true);
 492   base::MessageLoop::current()->Quit();
 493 }
 494
 495 bool ChildThreadImpl::Send(IPC::Message* msg) {
 496   DCHECK(base::MessageLoop::current() == message_loop());
 497   if (!channel_) {
 498     delete msg;
 499     return false;
 500   }
 501
 502   return channel_->Send(msg);
 503 }
 504
 505 #if defined(OS_WIN)
 506 void ChildThreadImpl::PreCacheFont(const LOGFONT& log_font) {
 507   Send(new ChildProcessHostMsg_PreCacheFont(log_font));
 508 }
 509
 510 void ChildThreadImpl::ReleaseCachedFonts() {
 511   Send(new ChildProcessHostMsg_ReleaseCachedFonts());
 512 }
 513 #endif
 514
 515 MessageRouter* ChildThreadImpl::GetRouter() {
 516   DCHECK(base::MessageLoop::current() == message_loop());
 517   return &router_;
 518 }
 519
 520 scoped_ptr<base::SharedMemory> ChildThreadImpl::AllocateSharedMemory(
 521     size_t buf_size) {
 522   DCHECK(base::MessageLoop::current() == message_loop());
 523   return AllocateSharedMemory(buf_size, this);
 524 }
 525
 526 // static
 527 scoped_ptr<base::SharedMemory> ChildThreadImpl::AllocateSharedMemory(
 528     size_t buf_size,
 529     IPC::Sender* sender) {
 530   scoped_ptr<base::SharedMemory> shared_buf;
 531 #if defined(OS_WIN)
 532   shared_buf.reset(new base::SharedMemory);
 533   if (!shared_buf->CreateAnonymous(buf_size)) {
 534     NOTREACHED();
 535     return NULL;
 536   }
 537 #else
 538   // On POSIX, we need to ask the browser to create the shared memory for us,
 539   // since this is blocked by the sandbox.
 540   base::SharedMemoryHandle shared_mem_handle;
 541   if (sender->Send(new ChildProcessHostMsg_SyncAllocateSharedMemory(
 542                            buf_size, &shared_mem_handle))) {
 543     if (base::SharedMemory::IsHandleValid(shared_mem_handle)) {
 544       shared_buf.reset(new base::SharedMemory(shared_mem_handle, false));
 545     } else {
 546       NOTREACHED() << "Browser failed to allocate shared memory";
 547       return NULL;
 548     }
 549   } else {
 550     NOTREACHED() << "Browser allocation request message failed";
 551     return NULL;
 552   }
 553 #endif
 554   return shared_buf;
 555 }
 556
 557 bool ChildThreadImpl::OnMessageReceived(const IPC::Message& msg) {
 558   if (mojo_application_->OnMessageReceived(msg))
 559     return true;
 560
 561   // Resource responses are sent to the resource dispatcher.
 562   if (resource_dispatcher_->OnMessageReceived(msg))
 563     return true;
 564   if (websocket_dispatcher_->OnMessageReceived(msg))
 565     return true;
 566   if (file_system_dispatcher_->OnMessageReceived(msg))
 567     return true;
 568
 569   bool handled = true;
 570   IPC_BEGIN_MESSAGE_MAP(ChildThreadImpl, msg)
 571     IPC_MESSAGE_HANDLER(ChildProcessMsg_Shutdown, OnShutdown)
 572 #if defined(IPC_MESSAGE_LOG_ENABLED)
 573     IPC_MESSAGE_HANDLER(ChildProcessMsg_SetIPCLoggingEnabled,
 574                         OnSetIPCLoggingEnabled)
 575 #endif
 576     IPC_MESSAGE_HANDLER(ChildProcessMsg_SetProfilerStatus,
 577                         OnSetProfilerStatus)
 578     IPC_MESSAGE_HANDLER(ChildProcessMsg_GetChildProfilerData,
 579                         OnGetChildProfilerData)
 580     IPC_MESSAGE_HANDLER(ChildProcessMsg_DumpHandles, OnDumpHandles)
 581     IPC_MESSAGE_HANDLER(ChildProcessMsg_SetProcessBackgrounded,
 582                         OnProcessBackgrounded)
 583 #if defined(USE_TCMALLOC)
 584     IPC_MESSAGE_HANDLER(ChildProcessMsg_GetTcmallocStats, OnGetTcmallocStats)
 585 #endif
 586     IPC_MESSAGE_UNHANDLED(handled = false)
 587   IPC_END_MESSAGE_MAP()
 588
 589   if (handled)
 590     return true;
 591
 592   if (msg.routing_id() == MSG_ROUTING_CONTROL)
 593     return OnControlMessageReceived(msg);
 594
 595   return router_.OnMessageReceived(msg);
 596 }
 597
 598 bool ChildThreadImpl::OnControlMessageReceived(const IPC::Message& msg) {
 599   return false;
 600 }
 601
 602 void ChildThreadImpl::OnShutdown() {
 603   base::MessageLoop::current()->Quit();
 604 }
 605
 606 #if defined(IPC_MESSAGE_LOG_ENABLED)
 607 void ChildThreadImpl::OnSetIPCLoggingEnabled(bool enable) {
 608   if (enable)
 609     IPC::Logging::GetInstance()->Enable();
 610   else
 611     IPC::Logging::GetInstance()->Disable();
 612 }
 613 #endif  //  IPC_MESSAGE_LOG_ENABLED
 614
 615 void ChildThreadImpl::OnSetProfilerStatus(ThreadData::Status status) {
 616   ThreadData::InitializeAndSetTrackingStatus(status);
 617 }
 618
 619 void ChildThreadImpl::OnGetChildProfilerData(int sequence_number) {
 620   tracked_objects::ProcessDataSnapshot process_data;
 621   ThreadData::Snapshot(false, &process_data);
 622
 623   Send(new ChildProcessHostMsg_ChildProfilerData(sequence_number,
 624                                                  process_data));
 625 }
 626
 627 void ChildThreadImpl::OnDumpHandles() {
 628 #if defined(OS_WIN)
 629   scoped_refptr<HandleEnumerator> handle_enum(
 630       new HandleEnumerator(
 631           base::CommandLine::ForCurrentProcess()->HasSwitch(
 632               switches::kAuditAllHandles)));
 633   handle_enum->EnumerateHandles();
 634   Send(new ChildProcessHostMsg_DumpHandlesDone);
 635 #else
 636   NOTIMPLEMENTED();
 637 #endif
 638 }
 639
 640 #if defined(USE_TCMALLOC)
 641 void ChildThreadImpl::OnGetTcmallocStats() {
 642   std::string result;
 643   char buffer[1024 * 32];
 644   base::allocator::GetStats(buffer, sizeof(buffer));
 645   result.append(buffer);
 646   Send(new ChildProcessHostMsg_TcmallocStats(result));
 647 }
 648 #endif
 649
 650 ChildThreadImpl* ChildThreadImpl::current() {
 651   return g_lazy_tls.Pointer()->Get();
 652 }
 653
 654 #if defined(OS_ANDROID)
 655 // The method must NOT be called on the child thread itself.
 656 // It may block the child thread if so.
 657 void ChildThreadImpl::ShutdownThread() {
 658   DCHECK(!ChildThreadImpl::current()) <<
 659       "this method should NOT be called from child thread itself";
 660   {
 661     base::AutoLock lock(g_lazy_child_thread_lock.Get());
 662     while (!g_child_thread_initialized)
 663       g_lazy_child_thread_cv.Get().Wait();
 664
 665     // g_child_thread may already have been destructed while we didn't hold the
 666     // lock.
 667     if (!g_child_thread)
 668       return;
 669
 670     DCHECK_NE(base::MessageLoop::current(), g_child_thread->message_loop());
 671     g_child_thread->message_loop()->PostTask(
 672         FROM_HERE, base::Bind(&QuitMainThreadMessageLoop));
 673   }
 674 }
 675 #endif
 676
 677 void ChildThreadImpl::OnProcessFinalRelease() {
 678   if (on_channel_error_called_) {
 679     base::MessageLoop::current()->Quit();
 680     return;
 681   }
 682
 683   // The child process shutdown sequence is a request response based mechanism,
 684   // where we send out an initial feeler request to the child process host
 685   // instance in the browser to verify if it's ok to shutdown the child process.
 686   // The browser then sends back a response if it's ok to shutdown. This avoids
 687   // race conditions if the process refcount is 0 but there's an IPC message
 688   // inflight that would addref it.
 689   Send(new ChildProcessHostMsg_ShutdownRequest);
 690 }
 691
 692 void ChildThreadImpl::EnsureConnected() {
 693   VLOG(0) << "ChildThreadImpl::EnsureConnected()";
 694   base::KillProcess(base::GetCurrentProcessHandle(), 0, false);
 695 }
 696
 697 void ChildThreadImpl::OnProcessBackgrounded(bool background) {
 698   // Set timer slack to maximum on main thread when in background.
 699   base::TimerSlack timer_slack = base::TIMER_SLACK_NONE;
 700   if (background)
 701     timer_slack = base::TIMER_SLACK_MAXIMUM;
 702   base::MessageLoop::current()->SetTimerSlack(timer_slack);
 703
 704 #ifdef OS_WIN
 705   // Windows Vista+ has a fancy process backgrounding mode that can only be set
 706   // from within the process. This used to be how chrome set its renderers into
 707   // background mode on Windows but was removed due to http://crbug.com/398103.
 708   // As we experiment with bringing back some other form of background mode for
 709   // hidden renderers, add a bucket to allow us to trigger this undesired method
 710   // of setting background state in order to confirm that the metrics which were
 711   // added to prevent regressions on the aforementioned issue indeed catch such
 712   // regressions and are thus a reliable way to confirm that our latest proposal
 713   // doesn't cause such issues. TODO(gab): Remove this once the experiment is
 714   // over (http://crbug.com/458594).
 715   base::FieldTrial* trial =
 716       base::FieldTrialList::Find("BackgroundRendererProcesses");
 717   if (trial && trial->group_name() == "AllowBackgroundModeFromRenderer")
 718     base::Process::Current().SetProcessBackgrounded(background);
 719 #endif  // OS_WIN
 720 }
 721
 722 }  // namespace content