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      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.h"
      6 
      7 #include <string>
      8 
      9 #include "base/allocator/allocator_extension.h"
     10 #include "base/base_switches.h"
     11 #include "base/command_line.h"
     12 #include "base/debug/leak_annotations.h"
     13 #include "base/lazy_instance.h"
     14 #include "base/message_loop/message_loop.h"
     15 #include "base/process/kill.h"
     16 #include "base/process/process_handle.h"
     17 #include "base/strings/string_util.h"
     18 #include "base/synchronization/condition_variable.h"
     19 #include "base/synchronization/lock.h"
     20 #include "base/threading/thread_local.h"
     21 #include "base/tracked_objects.h"
     22 #include "components/tracing/child_trace_message_filter.h"
     23 #include "content/child/child_histogram_message_filter.h"
     24 #include "content/child/child_process.h"
     25 #include "content/child/child_resource_message_filter.h"
     26 #include "content/child/fileapi/file_system_dispatcher.h"
     27 #include "content/child/power_monitor_broadcast_source.h"
     28 #include "content/child/quota_dispatcher.h"
     29 #include "content/child/quota_message_filter.h"
     30 #include "content/child/resource_dispatcher.h"
     31 #include "content/child/service_worker/service_worker_dispatcher.h"
     32 #include "content/child/service_worker/service_worker_message_filter.h"
     33 #include "content/child/socket_stream_dispatcher.h"
     34 #include "content/child/thread_safe_sender.h"
     35 #include "content/child/websocket_dispatcher.h"
     36 #include "content/common/child_process_messages.h"
     37 #include "content/public/common/content_switches.h"
     38 #include "ipc/ipc_logging.h"
     39 #include "ipc/ipc_switches.h"
     40 #include "ipc/ipc_sync_channel.h"
     41 #include "ipc/ipc_sync_message_filter.h"
     42 
     43 #if defined(OS_WIN)
     44 #include "content/common/handle_enumerator_win.h"
     45 #endif
     46 
     47 #if defined(TCMALLOC_TRACE_MEMORY_SUPPORTED)
     48 #include "third_party/tcmalloc/chromium/src/gperftools/heap-profiler.h"
     49 #endif
     50 
     51 using tracked_objects::ThreadData;
     52 
     53 namespace content {
     54 namespace {
     55 
     56 // How long to wait for a connection to the browser process before giving up.
     57 const int kConnectionTimeoutS = 15;
     58 
     59 base::LazyInstance<base::ThreadLocalPointer<ChildThread> > g_lazy_tls =
     60     LAZY_INSTANCE_INITIALIZER;
     61 
     62 // This isn't needed on Windows because there the sandbox's job object
     63 // terminates child processes automatically. For unsandboxed processes (i.e.
     64 // plugins), PluginThread has EnsureTerminateMessageFilter.
     65 #if defined(OS_POSIX)
     66 
     67 class SuicideOnChannelErrorFilter : public IPC::ChannelProxy::MessageFilter {
     68  public:
     69   // IPC::ChannelProxy::MessageFilter
     70   virtual void OnChannelError() OVERRIDE {
     71     // For renderer/worker processes:
     72     // On POSIX, at least, one can install an unload handler which loops
     73     // forever and leave behind a renderer process which eats 100% CPU forever.
     74     //
     75     // This is because the terminate signals (ViewMsg_ShouldClose and the error
     76     // from the IPC channel) are routed to the main message loop but never
     77     // processed (because that message loop is stuck in V8).
     78     //
     79     // One could make the browser SIGKILL the renderers, but that leaves open a
     80     // large window where a browser failure (or a user, manually terminating
     81     // the browser because "it's stuck") will leave behind a process eating all
     82     // the CPU.
     83     //
     84     // So, we install a filter on the channel so that we can process this event
     85     // here and kill the process.
     86     if (CommandLine::ForCurrentProcess()->
     87         HasSwitch(switches::kChildCleanExit)) {
     88       // If clean exit is requested, we want to kill this process after giving
     89       // it 60 seconds to run exit handlers. Exit handlers may including ones
     90       // that write profile data to disk (which happens under profile collection
     91       // mode).
     92       alarm(60);
     93 #if defined(LEAK_SANITIZER)
     94       // Invoke LeakSanitizer early to avoid detecting shutdown-only leaks. If
     95       // leaks are found, the process will exit here.
     96       __lsan_do_leak_check();
     97 #endif
     98     } else {
     99       _exit(0);
    100     }
    101   }
    102 
    103  protected:
    104   virtual ~SuicideOnChannelErrorFilter() {}
    105 };
    106 
    107 #endif  // OS(POSIX)
    108 
    109 #if defined(OS_ANDROID)
    110 ChildThread* g_child_thread = NULL;
    111 
    112 // A lock protects g_child_thread.
    113 base::LazyInstance<base::Lock> g_lazy_child_thread_lock =
    114     LAZY_INSTANCE_INITIALIZER;
    115 
    116 // base::ConditionVariable has an explicit constructor that takes
    117 // a base::Lock pointer as parameter. The base::DefaultLazyInstanceTraits
    118 // doesn't handle the case. Thus, we need our own class here.
    119 struct CondVarLazyInstanceTraits {
    120   static const bool kRegisterOnExit = true;
    121   static const bool kAllowedToAccessOnNonjoinableThread ALLOW_UNUSED = false;
    122   static base::ConditionVariable* New(void* instance) {
    123     return new (instance) base::ConditionVariable(
    124         g_lazy_child_thread_lock.Pointer());
    125   }
    126   static void Delete(base::ConditionVariable* instance) {
    127     instance->~ConditionVariable();
    128   }
    129 };
    130 
    131 // A condition variable that synchronize threads initializing and waiting
    132 // for g_child_thread.
    133 base::LazyInstance<base::ConditionVariable, CondVarLazyInstanceTraits>
    134     g_lazy_child_thread_cv = LAZY_INSTANCE_INITIALIZER;
    135 
    136 void QuitMainThreadMessageLoop() {
    137   base::MessageLoop::current()->Quit();
    138 }
    139 
    140 #endif
    141 
    142 }  // namespace
    143 
    144 ChildThread::ChildThread()
    145     : channel_connected_factory_(this),
    146       in_browser_process_(false) {
    147   channel_name_ = CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
    148       switches::kProcessChannelID);
    149   Init();
    150 }
    151 
    152 ChildThread::ChildThread(const std::string& channel_name)
    153     : channel_name_(channel_name),
    154       channel_connected_factory_(this),
    155       in_browser_process_(true) {
    156   Init();
    157 }
    158 
    159 void ChildThread::Init() {
    160   g_lazy_tls.Pointer()->Set(this);
    161   on_channel_error_called_ = false;
    162   message_loop_ = base::MessageLoop::current();
    163 #ifdef IPC_MESSAGE_LOG_ENABLED
    164   // We must make sure to instantiate the IPC Logger *before* we create the
    165   // channel, otherwise we can get a callback on the IO thread which creates
    166   // the logger, and the logger does not like being created on the IO thread.
    167   IPC::Logging::GetInstance();
    168 #endif
    169   channel_.reset(
    170       new IPC::SyncChannel(channel_name_,
    171                            IPC::Channel::MODE_CLIENT,
    172                            this,
    173                            ChildProcess::current()->io_message_loop_proxy(),
    174                            true,
    175                            ChildProcess::current()->GetShutDownEvent()));
    176 #ifdef IPC_MESSAGE_LOG_ENABLED
    177   if (!in_browser_process_)
    178     IPC::Logging::GetInstance()->SetIPCSender(this);
    179 #endif
    180 
    181   sync_message_filter_ =
    182       new IPC::SyncMessageFilter(ChildProcess::current()->GetShutDownEvent());
    183   thread_safe_sender_ = new ThreadSafeSender(
    184       base::MessageLoopProxy::current().get(), sync_message_filter_.get());
    185 
    186   resource_dispatcher_.reset(new ResourceDispatcher(this));
    187   socket_stream_dispatcher_.reset(new SocketStreamDispatcher());
    188   websocket_dispatcher_.reset(new WebSocketDispatcher);
    189   file_system_dispatcher_.reset(new FileSystemDispatcher());
    190 
    191   histogram_message_filter_ = new ChildHistogramMessageFilter();
    192   resource_message_filter_ =
    193       new ChildResourceMessageFilter(resource_dispatcher());
    194 
    195   service_worker_message_filter_ =
    196       new ServiceWorkerMessageFilter(thread_safe_sender_.get());
    197   service_worker_dispatcher_.reset(
    198       new ServiceWorkerDispatcher(thread_safe_sender_.get()));
    199 
    200   quota_message_filter_ =
    201       new QuotaMessageFilter(thread_safe_sender_.get());
    202   quota_dispatcher_.reset(new QuotaDispatcher(thread_safe_sender_.get(),
    203                                               quota_message_filter_.get()));
    204 
    205   channel_->AddFilter(histogram_message_filter_.get());
    206   channel_->AddFilter(sync_message_filter_.get());
    207   channel_->AddFilter(new tracing::ChildTraceMessageFilter(
    208       ChildProcess::current()->io_message_loop_proxy()));
    209   channel_->AddFilter(resource_message_filter_.get());
    210   channel_->AddFilter(quota_message_filter_->GetFilter());
    211   channel_->AddFilter(service_worker_message_filter_->GetFilter());
    212 
    213   // In single process mode we may already have a power monitor
    214   if (!base::PowerMonitor::Get()) {
    215     scoped_ptr<PowerMonitorBroadcastSource> power_monitor_source(
    216       new PowerMonitorBroadcastSource());
    217     channel_->AddFilter(power_monitor_source->GetMessageFilter());
    218 
    219     power_monitor_.reset(new base::PowerMonitor(
    220         power_monitor_source.PassAs<base::PowerMonitorSource>()));
    221   }
    222 
    223 #if defined(OS_POSIX)
    224   // Check that --process-type is specified so we don't do this in unit tests
    225   // and single-process mode.
    226   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kProcessType))
    227     channel_->AddFilter(new SuicideOnChannelErrorFilter());
    228 #endif
    229 
    230   base::MessageLoop::current()->PostDelayedTask(
    231       FROM_HERE,
    232       base::Bind(&ChildThread::EnsureConnected,
    233                  channel_connected_factory_.GetWeakPtr()),
    234       base::TimeDelta::FromSeconds(kConnectionTimeoutS));
    235 
    236 #if defined(OS_ANDROID)
    237   {
    238     base::AutoLock lock(g_lazy_child_thread_lock.Get());
    239     g_child_thread = this;
    240   }
    241   // Signalling without locking is fine here because only
    242   // one thread can wait on the condition variable.
    243   g_lazy_child_thread_cv.Get().Signal();
    244 #endif
    245 
    246 #if defined(TCMALLOC_TRACE_MEMORY_SUPPORTED)
    247   trace_memory_controller_.reset(new base::debug::TraceMemoryController(
    248       message_loop_->message_loop_proxy(),
    249       ::HeapProfilerWithPseudoStackStart,
    250       ::HeapProfilerStop,
    251       ::GetHeapProfile));
    252 #endif
    253 }
    254 
    255 ChildThread::~ChildThread() {
    256 #ifdef IPC_MESSAGE_LOG_ENABLED
    257   IPC::Logging::GetInstance()->SetIPCSender(NULL);
    258 #endif
    259 
    260   channel_->RemoveFilter(histogram_message_filter_.get());
    261   channel_->RemoveFilter(sync_message_filter_.get());
    262 
    263   // The ChannelProxy object caches a pointer to the IPC thread, so need to
    264   // reset it as it's not guaranteed to outlive this object.
    265   // NOTE: this also has the side-effect of not closing the main IPC channel to
    266   // the browser process.  This is needed because this is the signal that the
    267   // browser uses to know that this process has died, so we need it to be alive
    268   // until this process is shut down, and the OS closes the handle
    269   // automatically.  We used to watch the object handle on Windows to do this,
    270   // but it wasn't possible to do so on POSIX.
    271   channel_->ClearIPCTaskRunner();
    272   g_lazy_tls.Pointer()->Set(NULL);
    273 }
    274 
    275 void ChildThread::Shutdown() {
    276   // Delete objects that hold references to blink so derived classes can
    277   // safely shutdown blink in their Shutdown implementation.
    278   file_system_dispatcher_.reset();
    279   quota_dispatcher_.reset();
    280 }
    281 
    282 void ChildThread::OnChannelConnected(int32 peer_pid) {
    283   channel_connected_factory_.InvalidateWeakPtrs();
    284 }
    285 
    286 void ChildThread::OnChannelError() {
    287   set_on_channel_error_called(true);
    288   base::MessageLoop::current()->Quit();
    289 }
    290 
    291 bool ChildThread::Send(IPC::Message* msg) {
    292   DCHECK(base::MessageLoop::current() == message_loop());
    293   if (!channel_) {
    294     delete msg;
    295     return false;
    296   }
    297 
    298   return channel_->Send(msg);
    299 }
    300 
    301 void ChildThread::AddRoute(int32 routing_id, IPC::Listener* listener) {
    302   DCHECK(base::MessageLoop::current() == message_loop());
    303 
    304   router_.AddRoute(routing_id, listener);
    305 }
    306 
    307 void ChildThread::RemoveRoute(int32 routing_id) {
    308   DCHECK(base::MessageLoop::current() == message_loop());
    309 
    310   router_.RemoveRoute(routing_id);
    311 }
    312 
    313 webkit_glue::ResourceLoaderBridge* ChildThread::CreateBridge(
    314     const webkit_glue::ResourceLoaderBridge::RequestInfo& request_info) {
    315   return resource_dispatcher()->CreateBridge(request_info);
    316 }
    317 
    318 base::SharedMemory* ChildThread::AllocateSharedMemory(size_t buf_size) {
    319   return AllocateSharedMemory(buf_size, this);
    320 }
    321 
    322 // static
    323 base::SharedMemory* ChildThread::AllocateSharedMemory(
    324     size_t buf_size,
    325     IPC::Sender* sender) {
    326   scoped_ptr<base::SharedMemory> shared_buf;
    327 #if defined(OS_WIN)
    328   shared_buf.reset(new base::SharedMemory);
    329   if (!shared_buf->CreateAndMapAnonymous(buf_size)) {
    330     NOTREACHED();
    331     return NULL;
    332   }
    333 #else
    334   // On POSIX, we need to ask the browser to create the shared memory for us,
    335   // since this is blocked by the sandbox.
    336   base::SharedMemoryHandle shared_mem_handle;
    337   if (sender->Send(new ChildProcessHostMsg_SyncAllocateSharedMemory(
    338                            buf_size, &shared_mem_handle))) {
    339     if (base::SharedMemory::IsHandleValid(shared_mem_handle)) {
    340       shared_buf.reset(new base::SharedMemory(shared_mem_handle, false));
    341       if (!shared_buf->Map(buf_size)) {
    342         NOTREACHED() << "Map failed";
    343         return NULL;
    344       }
    345     } else {
    346       NOTREACHED() << "Browser failed to allocate shared memory";
    347       return NULL;
    348     }
    349   } else {
    350     NOTREACHED() << "Browser allocation request message failed";
    351     return NULL;
    352   }
    353 #endif
    354   return shared_buf.release();
    355 }
    356 
    357 bool ChildThread::OnMessageReceived(const IPC::Message& msg) {
    358   // Resource responses are sent to the resource dispatcher.
    359   if (resource_dispatcher_->OnMessageReceived(msg))
    360     return true;
    361   if (socket_stream_dispatcher_->OnMessageReceived(msg))
    362     return true;
    363   if (websocket_dispatcher_->OnMessageReceived(msg))
    364     return true;
    365   if (file_system_dispatcher_->OnMessageReceived(msg))
    366     return true;
    367 
    368   bool handled = true;
    369   IPC_BEGIN_MESSAGE_MAP(ChildThread, msg)
    370     IPC_MESSAGE_HANDLER(ChildProcessMsg_Shutdown, OnShutdown)
    371 #if defined(IPC_MESSAGE_LOG_ENABLED)
    372     IPC_MESSAGE_HANDLER(ChildProcessMsg_SetIPCLoggingEnabled,
    373                         OnSetIPCLoggingEnabled)
    374 #endif
    375     IPC_MESSAGE_HANDLER(ChildProcessMsg_SetProfilerStatus,
    376                         OnSetProfilerStatus)
    377     IPC_MESSAGE_HANDLER(ChildProcessMsg_GetChildProfilerData,
    378                         OnGetChildProfilerData)
    379     IPC_MESSAGE_HANDLER(ChildProcessMsg_DumpHandles, OnDumpHandles)
    380 #if defined(USE_TCMALLOC)
    381     IPC_MESSAGE_HANDLER(ChildProcessMsg_GetTcmallocStats, OnGetTcmallocStats)
    382 #endif
    383     IPC_MESSAGE_UNHANDLED(handled = false)
    384   IPC_END_MESSAGE_MAP()
    385 
    386   if (handled)
    387     return true;
    388 
    389   if (msg.routing_id() == MSG_ROUTING_CONTROL)
    390     return OnControlMessageReceived(msg);
    391 
    392   return router_.OnMessageReceived(msg);
    393 }
    394 
    395 bool ChildThread::OnControlMessageReceived(const IPC::Message& msg) {
    396   return false;
    397 }
    398 
    399 void ChildThread::OnShutdown() {
    400   base::MessageLoop::current()->Quit();
    401 }
    402 
    403 #if defined(IPC_MESSAGE_LOG_ENABLED)
    404 void ChildThread::OnSetIPCLoggingEnabled(bool enable) {
    405   if (enable)
    406     IPC::Logging::GetInstance()->Enable();
    407   else
    408     IPC::Logging::GetInstance()->Disable();
    409 }
    410 #endif  //  IPC_MESSAGE_LOG_ENABLED
    411 
    412 void ChildThread::OnSetProfilerStatus(ThreadData::Status status) {
    413   ThreadData::InitializeAndSetTrackingStatus(status);
    414 }
    415 
    416 void ChildThread::OnGetChildProfilerData(int sequence_number) {
    417   tracked_objects::ProcessDataSnapshot process_data;
    418   ThreadData::Snapshot(false, &process_data);
    419 
    420   Send(new ChildProcessHostMsg_ChildProfilerData(sequence_number,
    421                                                  process_data));
    422 }
    423 
    424 void ChildThread::OnDumpHandles() {
    425 #if defined(OS_WIN)
    426   scoped_refptr<HandleEnumerator> handle_enum(
    427       new HandleEnumerator(
    428           CommandLine::ForCurrentProcess()->HasSwitch(
    429               switches::kAuditAllHandles)));
    430   handle_enum->EnumerateHandles();
    431   Send(new ChildProcessHostMsg_DumpHandlesDone);
    432   return;
    433 #endif
    434 
    435   NOTIMPLEMENTED();
    436 }
    437 
    438 #if defined(USE_TCMALLOC)
    439 void ChildThread::OnGetTcmallocStats() {
    440   std::string result;
    441   char buffer[1024 * 32];
    442   base::allocator::GetStats(buffer, sizeof(buffer));
    443   result.append(buffer);
    444   Send(new ChildProcessHostMsg_TcmallocStats(result));
    445 }
    446 #endif
    447 
    448 ChildThread* ChildThread::current() {
    449   return g_lazy_tls.Pointer()->Get();
    450 }
    451 
    452 #if defined(OS_ANDROID)
    453 // The method must NOT be called on the child thread itself.
    454 // It may block the child thread if so.
    455 void ChildThread::ShutdownThread() {
    456   DCHECK(!ChildThread::current()) <<
    457       "this method should NOT be called from child thread itself";
    458   {
    459     base::AutoLock lock(g_lazy_child_thread_lock.Get());
    460     while (!g_child_thread)
    461       g_lazy_child_thread_cv.Get().Wait();
    462   }
    463   DCHECK_NE(base::MessageLoop::current(), g_child_thread->message_loop());
    464   g_child_thread->message_loop()->PostTask(
    465       FROM_HERE, base::Bind(&QuitMainThreadMessageLoop));
    466 }
    467 
    468 #endif
    469 
    470 void ChildThread::OnProcessFinalRelease() {
    471   if (on_channel_error_called_) {
    472     base::MessageLoop::current()->Quit();
    473     return;
    474   }
    475 
    476   // The child process shutdown sequence is a request response based mechanism,
    477   // where we send out an initial feeler request to the child process host
    478   // instance in the browser to verify if it's ok to shutdown the child process.
    479   // The browser then sends back a response if it's ok to shutdown. This avoids
    480   // race conditions if the process refcount is 0 but there's an IPC message
    481   // inflight that would addref it.
    482   Send(new ChildProcessHostMsg_ShutdownRequest);
    483 }
    484 
    485 void ChildThread::EnsureConnected() {
    486   VLOG(0) << "ChildThread::EnsureConnected()";
    487   base::KillProcess(base::GetCurrentProcessHandle(), 0, false);
    488 }
    489 
    490 }  // namespace content
    491