content/common/child_process_host_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/common/child_process_host_impl.h"
   6
   7 #include <limits>
   8
   9 #include "base/atomic_sequence_num.h"
  10 #include "base/command_line.h"
  11 #include "base/files/file_path.h"
  12 #include "base/hash.h"
  13 #include "base/lazy_instance.h"
  14 #include "base/logging.h"
  15 #include "base/metrics/histogram.h"
  16 #include "base/numerics/safe_math.h"
  17 #include "base/path_service.h"
  18 #include "base/process/process_metrics.h"
  19 #include "base/rand_util.h"
  20 #include "base/strings/stringprintf.h"
  21 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
  22 #include "content/common/child_process_messages.h"
  23 #include "content/common/gpu/client/gpu_memory_buffer_impl_shared_memory.h"
  24 #include "content/public/common/child_process_host_delegate.h"
  25 #include "content/public/common/content_paths.h"
  26 #include "content/public/common/content_switches.h"
  27 #include "ipc/ipc_channel.h"
  28 #include "ipc/ipc_logging.h"
  29 #include "ipc/message_filter.h"
  30
  31 #if defined(OS_LINUX)
  32 #include "base/linux_util.h"
  33 #elif defined(OS_WIN)
  34 #include "content/common/font_cache_dispatcher_win.h"
  35 #include "ipc/attachment_broker_privileged_win.h"
  36 #endif  // OS_LINUX
  37
  38 #if defined(OS_WIN)
  39 base::LazyInstance<IPC::AttachmentBrokerPrivilegedWin>::Leaky
  40     g_attachment_broker = LAZY_INSTANCE_INITIALIZER;
  41 #endif  // defined(OS_WIN)
  42
  43 namespace {
  44
  45 #if defined(OS_MACOSX)
  46 // Given |path| identifying a Mac-style child process executable path, adjusts
  47 // it to correspond to |feature|. For a child process path such as
  48 // ".../Chromium Helper.app/Contents/MacOS/Chromium Helper", the transformed
  49 // path for feature "NP" would be
  50 // ".../Chromium Helper NP.app/Contents/MacOS/Chromium Helper NP". The new
  51 // path is returned.
  52 base::FilePath TransformPathForFeature(const base::FilePath& path,
  53                                  const std::string& feature) {
  54   std::string basename = path.BaseName().value();
  55
  56   base::FilePath macos_path = path.DirName();
  57   const char kMacOSName[] = "MacOS";
  58   DCHECK_EQ(kMacOSName, macos_path.BaseName().value());
  59
  60   base::FilePath contents_path = macos_path.DirName();
  61   const char kContentsName[] = "Contents";
  62   DCHECK_EQ(kContentsName, contents_path.BaseName().value());
  63
  64   base::FilePath helper_app_path = contents_path.DirName();
  65   const char kAppExtension[] = ".app";
  66   std::string basename_app = basename;
  67   basename_app.append(kAppExtension);
  68   DCHECK_EQ(basename_app, helper_app_path.BaseName().value());
  69
  70   base::FilePath root_path = helper_app_path.DirName();
  71
  72   std::string new_basename = basename;
  73   new_basename.append(1, ' ');
  74   new_basename.append(feature);
  75   std::string new_basename_app = new_basename;
  76   new_basename_app.append(kAppExtension);
  77
  78   base::FilePath new_path = root_path.Append(new_basename_app)
  79                                      .Append(kContentsName)
  80                                      .Append(kMacOSName)
  81                                      .Append(new_basename);
  82
  83   return new_path;
  84 }
  85 #endif  // OS_MACOSX
  86
  87 // Global atomic to generate child process unique IDs.
  88 base::StaticAtomicSequenceNumber g_unique_id;
  89
  90 }  // namespace
  91
  92 namespace content {
  93
  94 int ChildProcessHost::kInvalidUniqueID = -1;
  95
  96 uint64 ChildProcessHost::kBrowserTracingProcessId =
  97     std::numeric_limits<uint64>::max();
  98
  99 // static
 100 ChildProcessHost* ChildProcessHost::Create(ChildProcessHostDelegate* delegate) {
 101   return new ChildProcessHostImpl(delegate);
 102 }
 103
 104 // static
 105 base::FilePath ChildProcessHost::GetChildPath(int flags) {
 106   base::FilePath child_path;
 107
 108   child_path = base::CommandLine::ForCurrentProcess()->GetSwitchValuePath(
 109       switches::kBrowserSubprocessPath);
 110
 111 #if defined(OS_LINUX)
 112   // Use /proc/self/exe rather than our known binary path so updates
 113   // can't swap out the binary from underneath us.
 114   // When running under Valgrind, forking /proc/self/exe ends up forking the
 115   // Valgrind executable, which then crashes. However, it's almost safe to
 116   // assume that the updates won't happen while testing with Valgrind tools.
 117   if (child_path.empty() && flags & CHILD_ALLOW_SELF && !RunningOnValgrind())
 118     child_path = base::FilePath(base::kProcSelfExe);
 119 #endif
 120
 121   // On most platforms, the child executable is the same as the current
 122   // executable.
 123   if (child_path.empty())
 124     PathService::Get(CHILD_PROCESS_EXE, &child_path);
 125
 126 #if defined(OS_MACOSX)
 127   DCHECK(!(flags & CHILD_NO_PIE && flags & CHILD_ALLOW_HEAP_EXECUTION));
 128
 129   // If needed, choose an executable with special flags set that inform the
 130   // kernel to enable or disable specific optional process-wide features.
 131   if (flags & CHILD_NO_PIE) {
 132     // "NP" is "No PIE". This results in Chromium Helper NP.app or
 133     // Google Chrome Helper NP.app.
 134     child_path = TransformPathForFeature(child_path, "NP");
 135   } else if (flags & CHILD_ALLOW_HEAP_EXECUTION) {
 136     // "EH" is "Executable Heap". A non-executable heap is only available to
 137     // 32-bit processes on Mac OS X 10.7. Most code can and should run with a
 138     // non-executable heap, but the "EH" feature is provided to allow code
 139     // intolerant of a non-executable heap to work properly on 10.7. This
 140     // results in Chromium Helper EH.app or Google Chrome Helper EH.app.
 141     child_path = TransformPathForFeature(child_path, "EH");
 142   }
 143 #endif
 144
 145   return child_path;
 146 }
 147
 148 // static
 149 IPC::AttachmentBrokerPrivileged* ChildProcessHost::GetAttachmentBroker() {
 150 #if USE_ATTACHMENT_BROKER
 151   return &g_attachment_broker.Get();
 152 #else
 153   return nullptr;
 154 #endif  // USE_ATTACHMENT_BROKER
 155 }
 156
 157 ChildProcessHostImpl::ChildProcessHostImpl(ChildProcessHostDelegate* delegate)
 158     : delegate_(delegate),
 159       opening_channel_(false) {
 160 #if defined(OS_WIN)
 161   AddFilter(new FontCacheDispatcher());
 162 #endif
 163 }
 164
 165 ChildProcessHostImpl::~ChildProcessHostImpl() {
 166 #if USE_ATTACHMENT_BROKER
 167   g_attachment_broker.Get().DeregisterCommunicationChannel(channel_.get());
 168 #endif
 169   for (size_t i = 0; i < filters_.size(); ++i) {
 170     filters_[i]->OnChannelClosing();
 171     filters_[i]->OnFilterRemoved();
 172   }
 173 }
 174
 175 void ChildProcessHostImpl::AddFilter(IPC::MessageFilter* filter) {
 176   filters_.push_back(filter);
 177
 178   if (channel_)
 179     filter->OnFilterAdded(channel_.get());
 180 }
 181
 182 void ChildProcessHostImpl::ForceShutdown() {
 183   Send(new ChildProcessMsg_Shutdown());
 184 }
 185
 186 std::string ChildProcessHostImpl::CreateChannel() {
 187   channel_id_ = IPC::Channel::GenerateVerifiedChannelID(std::string());
 188   channel_ =
 189       IPC::Channel::CreateServer(channel_id_, this, GetAttachmentBroker());
 190   if (!channel_->Connect())
 191     return std::string();
 192 #if USE_ATTACHMENT_BROKER
 193   g_attachment_broker.Get().RegisterCommunicationChannel(channel_.get());
 194 #endif
 195
 196   for (size_t i = 0; i < filters_.size(); ++i)
 197     filters_[i]->OnFilterAdded(channel_.get());
 198
 199   // Make sure these messages get sent first.
 200 #if defined(IPC_MESSAGE_LOG_ENABLED)
 201   bool enabled = IPC::Logging::GetInstance()->Enabled();
 202   Send(new ChildProcessMsg_SetIPCLoggingEnabled(enabled));
 203 #endif
 204
 205   opening_channel_ = true;
 206
 207   return channel_id_;
 208 }
 209
 210 bool ChildProcessHostImpl::IsChannelOpening() {
 211   return opening_channel_;
 212 }
 213
 214 #if defined(OS_POSIX)
 215 base::ScopedFD ChildProcessHostImpl::TakeClientFileDescriptor() {
 216   return channel_->TakeClientFileDescriptor();
 217 }
 218 #endif
 219
 220 bool ChildProcessHostImpl::Send(IPC::Message* message) {
 221   if (!channel_) {
 222     delete message;
 223     return false;
 224   }
 225   return channel_->Send(message);
 226 }
 227
 228 void ChildProcessHostImpl::AllocateSharedMemory(
 229       size_t buffer_size, base::ProcessHandle child_process_handle,
 230       base::SharedMemoryHandle* shared_memory_handle) {
 231   base::SharedMemory shared_buf;
 232   if (!shared_buf.CreateAnonymous(buffer_size)) {
 233     *shared_memory_handle = base::SharedMemory::NULLHandle();
 234     NOTREACHED() << "Cannot create shared memory buffer";
 235     return;
 236   }
 237   shared_buf.GiveToProcess(child_process_handle, shared_memory_handle);
 238 }
 239
 240 int ChildProcessHostImpl::GenerateChildProcessUniqueId() {
 241   // This function must be threadsafe.
 242   //
 243   // Historically, this function returned ids started with 1, so in several
 244   // places in the code a value of 0 (rather than kInvalidUniqueID) was used as
 245   // an invalid value. So we retain those semantics.
 246   int id = g_unique_id.GetNext() + 1;
 247
 248   CHECK_NE(0, id);
 249   CHECK_NE(kInvalidUniqueID, id);
 250
 251   return id;
 252 }
 253
 254 uint64 ChildProcessHostImpl::ChildProcessUniqueIdToTracingProcessId(
 255     int child_process_id) {
 256   // In single process mode, all the children are hosted in the same process,
 257   // therefore the generated memory dump guids should not be conditioned by the
 258   // child process id. The clients need not be aware of SPM and the conversion
 259   // takes care of the SPM special case while translating child process ids to
 260   // tracing process ids.
 261   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
 262           switches::kSingleProcess))
 263     return ChildProcessHost::kBrowserTracingProcessId;
 264
 265   // The hash value is incremented so that the tracing id is never equal to
 266   // MemoryDumpManager::kInvalidTracingProcessId.
 267   return static_cast<uint64>(
 268              base::Hash(reinterpret_cast<const char*>(&child_process_id),
 269                         sizeof(child_process_id))) +
 270          1;
 271 }
 272
 273 bool ChildProcessHostImpl::OnMessageReceived(const IPC::Message& msg) {
 274 #ifdef IPC_MESSAGE_LOG_ENABLED
 275   IPC::Logging* logger = IPC::Logging::GetInstance();
 276   if (msg.type() == IPC_LOGGING_ID) {
 277     logger->OnReceivedLoggingMessage(msg);
 278     return true;
 279   }
 280
 281   if (logger->Enabled())
 282     logger->OnPreDispatchMessage(msg);
 283 #endif
 284
 285   bool handled = false;
 286   for (size_t i = 0; i < filters_.size(); ++i) {
 287     if (filters_[i]->OnMessageReceived(msg)) {
 288       handled = true;
 289       break;
 290     }
 291   }
 292
 293   if (!handled) {
 294     handled = true;
 295     IPC_BEGIN_MESSAGE_MAP(ChildProcessHostImpl, msg)
 296       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ShutdownRequest,
 297                           OnShutdownRequest)
 298       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateSharedMemory,
 299                           OnAllocateSharedMemory)
 300       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer,
 301                           OnAllocateGpuMemoryBuffer)
 302       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_DeletedGpuMemoryBuffer,
 303                           OnDeletedGpuMemoryBuffer)
 304       IPC_MESSAGE_UNHANDLED(handled = false)
 305     IPC_END_MESSAGE_MAP()
 306
 307     if (!handled)
 308       handled = delegate_->OnMessageReceived(msg);
 309   }
 310
 311 #ifdef IPC_MESSAGE_LOG_ENABLED
 312   if (logger->Enabled())
 313     logger->OnPostDispatchMessage(msg, channel_id_);
 314 #endif
 315   return handled;
 316 }
 317
 318 void ChildProcessHostImpl::OnChannelConnected(int32 peer_pid) {
 319   if (!peer_process_.IsValid()) {
 320     peer_process_ = base::Process::OpenWithExtraPrivileges(peer_pid);
 321     if (!peer_process_.IsValid())
 322        peer_process_ = delegate_->GetProcess().Duplicate();
 323     DCHECK(peer_process_.IsValid());
 324   }
 325   opening_channel_ = false;
 326   delegate_->OnChannelConnected(peer_pid);
 327   for (size_t i = 0; i < filters_.size(); ++i)
 328     filters_[i]->OnChannelConnected(peer_pid);
 329 }
 330
 331 void ChildProcessHostImpl::OnChannelError() {
 332   opening_channel_ = false;
 333   delegate_->OnChannelError();
 334
 335   for (size_t i = 0; i < filters_.size(); ++i)
 336     filters_[i]->OnChannelError();
 337
 338   // This will delete host_, which will also destroy this!
 339   delegate_->OnChildDisconnected();
 340 }
 341
 342 void ChildProcessHostImpl::OnBadMessageReceived(const IPC::Message& message) {
 343   delegate_->OnBadMessageReceived(message);
 344 }
 345
 346 void ChildProcessHostImpl::OnAllocateSharedMemory(
 347     uint32 buffer_size,
 348     base::SharedMemoryHandle* handle) {
 349   AllocateSharedMemory(buffer_size, peer_process_.Handle(), handle);
 350 }
 351
 352 void ChildProcessHostImpl::OnShutdownRequest() {
 353   if (delegate_->CanShutdown())
 354     Send(new ChildProcessMsg_Shutdown());
 355 }
 356
 357 void ChildProcessHostImpl::OnAllocateGpuMemoryBuffer(
 358     gfx::GpuMemoryBufferId id,
 359     uint32 width,
 360     uint32 height,
 361     gfx::BufferFormat format,
 362     gfx::BufferUsage usage,
 363     gfx::GpuMemoryBufferHandle* handle) {
 364   // TODO(reveman): Add support for other types of GpuMemoryBuffers.
 365
 366   // AllocateForChildProcess() will check if |width| and |height| are valid
 367   // and handle failure in a controlled way when not. We just need to make
 368   // sure |format| and |usage| are supported here.
 369   if (GpuMemoryBufferImplSharedMemory::IsFormatSupported(format) &&
 370       GpuMemoryBufferImplSharedMemory::IsUsageSupported(usage)) {
 371     *handle = GpuMemoryBufferImplSharedMemory::AllocateForChildProcess(
 372         id, gfx::Size(width, height), format, peer_process_.Handle());
 373   }
 374 }
 375
 376 void ChildProcessHostImpl::OnDeletedGpuMemoryBuffer(
 377     gfx::GpuMemoryBufferId id,
 378     uint32 sync_point) {
 379   // Note: Nothing to do here as ownership of shared memory backed
 380   // GpuMemoryBuffers is passed with IPC.
 381 }
 382
 383 }  // namespace content