src/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/path_service.h"
  15 #include "base/process/process_metrics.h"
  16 #include "base/rand_util.h"
  17 #include "base/strings/stringprintf.h"
  18 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
  19 #include "content/common/child_process_messages.h"
  20 #include "content/common/gpu/client/gpu_memory_buffer_impl.h"
  21 #include "content/public/common/child_process_host_delegate.h"
  22 #include "content/public/common/content_paths.h"
  23 #include "content/public/common/content_switches.h"
  24 #include "ipc/ipc_channel.h"
  25 #include "ipc/ipc_logging.h"
  26 #include "ipc/message_filter.h"
  27
  28 #if defined(OS_LINUX)
  29 #include "base/linux_util.h"
  30 #elif defined(OS_WIN)
  31 #include "content/common/font_cache_dispatcher_win.h"
  32 #endif  // OS_LINUX
  33
  34 namespace {
  35
  36 #if defined(OS_MACOSX)
  37 // Given |path| identifying a Mac-style child process executable path, adjusts
  38 // it to correspond to |feature|. For a child process path such as
  39 // ".../Chromium Helper.app/Contents/MacOS/Chromium Helper", the transformed
  40 // path for feature "NP" would be
  41 // ".../Chromium Helper NP.app/Contents/MacOS/Chromium Helper NP". The new
  42 // path is returned.
  43 base::FilePath TransformPathForFeature(const base::FilePath& path,
  44                                  const std::string& feature) {
  45   std::string basename = path.BaseName().value();
  46
  47   base::FilePath macos_path = path.DirName();
  48   const char kMacOSName[] = "MacOS";
  49   DCHECK_EQ(kMacOSName, macos_path.BaseName().value());
  50
  51   base::FilePath contents_path = macos_path.DirName();
  52   const char kContentsName[] = "Contents";
  53   DCHECK_EQ(kContentsName, contents_path.BaseName().value());
  54
  55   base::FilePath helper_app_path = contents_path.DirName();
  56   const char kAppExtension[] = ".app";
  57   std::string basename_app = basename;
  58   basename_app.append(kAppExtension);
  59   DCHECK_EQ(basename_app, helper_app_path.BaseName().value());
  60
  61   base::FilePath root_path = helper_app_path.DirName();
  62
  63   std::string new_basename = basename;
  64   new_basename.append(1, ' ');
  65   new_basename.append(feature);
  66   std::string new_basename_app = new_basename;
  67   new_basename_app.append(kAppExtension);
  68
  69   base::FilePath new_path = root_path.Append(new_basename_app)
  70                                      .Append(kContentsName)
  71                                      .Append(kMacOSName)
  72                                      .Append(new_basename);
  73
  74   return new_path;
  75 }
  76 #endif  // OS_MACOSX
  77
  78 // Global atomic to generate child process unique IDs.
  79 base::StaticAtomicSequenceNumber g_unique_id;
  80
  81 }  // namespace
  82
  83 namespace content {
  84
  85 int ChildProcessHost::kInvalidUniqueID = -1;
  86
  87 // static
  88 ChildProcessHost* ChildProcessHost::Create(ChildProcessHostDelegate* delegate) {
  89   return new ChildProcessHostImpl(delegate);
  90 }
  91
  92 // static
  93 base::FilePath ChildProcessHost::GetChildPath(int flags) {
  94   base::FilePath child_path;
  95
  96   child_path = CommandLine::ForCurrentProcess()->GetSwitchValuePath(
  97       switches::kBrowserSubprocessPath);
  98
  99 #if defined(OS_LINUX)
 100   // Use /proc/self/exe rather than our known binary path so updates
 101   // can't swap out the binary from underneath us.
 102   // When running under Valgrind, forking /proc/self/exe ends up forking the
 103   // Valgrind executable, which then crashes. However, it's almost safe to
 104   // assume that the updates won't happen while testing with Valgrind tools.
 105   if (child_path.empty() && flags & CHILD_ALLOW_SELF && !RunningOnValgrind())
 106     child_path = base::FilePath(base::kProcSelfExe);
 107 #endif
 108
 109   // On most platforms, the child executable is the same as the current
 110   // executable.
 111   if (child_path.empty())
 112     PathService::Get(CHILD_PROCESS_EXE, &child_path);
 113
 114 #if defined(OS_MACOSX)
 115   DCHECK(!(flags & CHILD_NO_PIE && flags & CHILD_ALLOW_HEAP_EXECUTION));
 116
 117   // If needed, choose an executable with special flags set that inform the
 118   // kernel to enable or disable specific optional process-wide features.
 119   if (flags & CHILD_NO_PIE) {
 120     // "NP" is "No PIE". This results in Chromium Helper NP.app or
 121     // Google Chrome Helper NP.app.
 122     child_path = TransformPathForFeature(child_path, "NP");
 123   } else if (flags & CHILD_ALLOW_HEAP_EXECUTION) {
 124     // "EH" is "Executable Heap". A non-executable heap is only available to
 125     // 32-bit processes on Mac OS X 10.7. Most code can and should run with a
 126     // non-executable heap, but the "EH" feature is provided to allow code
 127     // intolerant of a non-executable heap to work properly on 10.7. This
 128     // results in Chromium Helper EH.app or Google Chrome Helper EH.app.
 129     child_path = TransformPathForFeature(child_path, "EH");
 130   }
 131 #endif
 132
 133   return child_path;
 134 }
 135
 136 ChildProcessHostImpl::ChildProcessHostImpl(ChildProcessHostDelegate* delegate)
 137     : delegate_(delegate),
 138       peer_handle_(base::kNullProcessHandle),
 139       opening_channel_(false) {
 140 #if defined(OS_WIN)
 141   AddFilter(new FontCacheDispatcher());
 142 #endif
 143 }
 144
 145 ChildProcessHostImpl::~ChildProcessHostImpl() {
 146   for (size_t i = 0; i < filters_.size(); ++i) {
 147     filters_[i]->OnChannelClosing();
 148     filters_[i]->OnFilterRemoved();
 149   }
 150
 151   base::CloseProcessHandle(peer_handle_);
 152 }
 153
 154 void ChildProcessHostImpl::AddFilter(IPC::MessageFilter* filter) {
 155   filters_.push_back(filter);
 156
 157   if (channel_)
 158     filter->OnFilterAdded(channel_.get());
 159 }
 160
 161 void ChildProcessHostImpl::ForceShutdown() {
 162   Send(new ChildProcessMsg_Shutdown());
 163 }
 164
 165 std::string ChildProcessHostImpl::CreateChannel() {
 166   channel_id_ = IPC::Channel::GenerateVerifiedChannelID(std::string());
 167   channel_.reset(new IPC::Channel(
 168       channel_id_, IPC::Channel::MODE_SERVER, 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 int 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_UNHANDLED(handled = false)
 260     IPC_END_MESSAGE_MAP()
 261
 262     if (!handled)
 263       handled = delegate_->OnMessageReceived(msg);
 264   }
 265
 266 #ifdef IPC_MESSAGE_LOG_ENABLED
 267   if (logger->Enabled())
 268     logger->OnPostDispatchMessage(msg, channel_id_);
 269 #endif
 270   return handled;
 271 }
 272
 273 void ChildProcessHostImpl::OnChannelConnected(int32 peer_pid) {
 274   if (!peer_handle_ &&
 275       !base::OpenPrivilegedProcessHandle(peer_pid, &peer_handle_) &&
 276       !(peer_handle_ = delegate_->GetHandle())) {
 277     NOTREACHED();
 278   }
 279   opening_channel_ = false;
 280   delegate_->OnChannelConnected(peer_pid);
 281   for (size_t i = 0; i < filters_.size(); ++i)
 282     filters_[i]->OnChannelConnected(peer_pid);
 283 }
 284
 285 void ChildProcessHostImpl::OnChannelError() {
 286   opening_channel_ = false;
 287   delegate_->OnChannelError();
 288
 289   for (size_t i = 0; i < filters_.size(); ++i)
 290     filters_[i]->OnChannelError();
 291
 292   // This will delete host_, which will also destroy this!
 293   delegate_->OnChildDisconnected();
 294 }
 295
 296 void ChildProcessHostImpl::OnAllocateSharedMemory(
 297     uint32 buffer_size,
 298     base::SharedMemoryHandle* handle) {
 299   AllocateSharedMemory(buffer_size, peer_handle_, handle);
 300 }
 301
 302 void ChildProcessHostImpl::OnShutdownRequest() {
 303   if (delegate_->CanShutdown())
 304     Send(new ChildProcessMsg_Shutdown());
 305 }
 306
 307 void ChildProcessHostImpl::OnAllocateGpuMemoryBuffer(
 308     uint32 width,
 309     uint32 height,
 310     uint32 internalformat,
 311     uint32 usage,
 312     gfx::GpuMemoryBufferHandle* handle) {
 313   handle->type = gfx::SHARED_MEMORY_BUFFER;
 314   AllocateSharedMemory(
 315       width * height * GpuMemoryBufferImpl::BytesPerPixel(internalformat),
 316       peer_handle_,
 317       &handle->handle);
 318 }
 319
 320 }  // namespace content