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