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.
TransformPathForFeature(const base::FilePath & path,const std::string & feature)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
Create(ChildProcessHostDelegate * delegate)88 ChildProcessHost* ChildProcessHost::Create(ChildProcessHostDelegate* delegate) {
89 return new ChildProcessHostImpl(delegate);
90 }
91
92 // static
GetChildPath(int flags)93 base::FilePath ChildProcessHost::GetChildPath(int flags) {
94 base::FilePath child_path;
95
96 child_path = base::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
ChildProcessHostImpl(ChildProcessHostDelegate * delegate)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
~ChildProcessHostImpl()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
AddFilter(IPC::MessageFilter * filter)154 void ChildProcessHostImpl::AddFilter(IPC::MessageFilter* filter) {
155 filters_.push_back(filter);
156
157 if (channel_)
158 filter->OnFilterAdded(channel_.get());
159 }
160
ForceShutdown()161 void ChildProcessHostImpl::ForceShutdown() {
162 Send(new ChildProcessMsg_Shutdown());
163 }
164
CreateChannel()165 std::string ChildProcessHostImpl::CreateChannel() {
166 channel_id_ = IPC::Channel::GenerateVerifiedChannelID(std::string());
167 channel_ = IPC::Channel::CreateServer(channel_id_, this);
168 if (!channel_->Connect())
169 return std::string();
170
171 for (size_t i = 0; i < filters_.size(); ++i)
172 filters_[i]->OnFilterAdded(channel_.get());
173
174 // Make sure these messages get sent first.
175 #if defined(IPC_MESSAGE_LOG_ENABLED)
176 bool enabled = IPC::Logging::GetInstance()->Enabled();
177 Send(new ChildProcessMsg_SetIPCLoggingEnabled(enabled));
178 #endif
179
180 opening_channel_ = true;
181
182 return channel_id_;
183 }
184
IsChannelOpening()185 bool ChildProcessHostImpl::IsChannelOpening() {
186 return opening_channel_;
187 }
188
189 #if defined(OS_POSIX)
TakeClientFileDescriptor()190 int ChildProcessHostImpl::TakeClientFileDescriptor() {
191 return channel_->TakeClientFileDescriptor();
192 }
193 #endif
194
Send(IPC::Message * message)195 bool ChildProcessHostImpl::Send(IPC::Message* message) {
196 if (!channel_) {
197 delete message;
198 return false;
199 }
200 return channel_->Send(message);
201 }
202
AllocateSharedMemory(size_t buffer_size,base::ProcessHandle child_process_handle,base::SharedMemoryHandle * shared_memory_handle)203 void ChildProcessHostImpl::AllocateSharedMemory(
204 size_t buffer_size, base::ProcessHandle child_process_handle,
205 base::SharedMemoryHandle* shared_memory_handle) {
206 base::SharedMemory shared_buf;
207 if (!shared_buf.CreateAnonymous(buffer_size)) {
208 *shared_memory_handle = base::SharedMemory::NULLHandle();
209 NOTREACHED() << "Cannot create shared memory buffer";
210 return;
211 }
212 shared_buf.GiveToProcess(child_process_handle, shared_memory_handle);
213 }
214
GenerateChildProcessUniqueId()215 int ChildProcessHostImpl::GenerateChildProcessUniqueId() {
216 // This function must be threadsafe.
217 //
218 // Historically, this function returned ids started with 1, so in several
219 // places in the code a value of 0 (rather than kInvalidUniqueID) was used as
220 // an invalid value. So we retain those semantics.
221 int id = g_unique_id.GetNext() + 1;
222
223 CHECK_NE(0, id);
224 CHECK_NE(kInvalidUniqueID, id);
225
226 return id;
227 }
228
OnMessageReceived(const IPC::Message & msg)229 bool ChildProcessHostImpl::OnMessageReceived(const IPC::Message& msg) {
230 #ifdef IPC_MESSAGE_LOG_ENABLED
231 IPC::Logging* logger = IPC::Logging::GetInstance();
232 if (msg.type() == IPC_LOGGING_ID) {
233 logger->OnReceivedLoggingMessage(msg);
234 return true;
235 }
236
237 if (logger->Enabled())
238 logger->OnPreDispatchMessage(msg);
239 #endif
240
241 bool handled = false;
242 for (size_t i = 0; i < filters_.size(); ++i) {
243 if (filters_[i]->OnMessageReceived(msg)) {
244 handled = true;
245 break;
246 }
247 }
248
249 if (!handled) {
250 handled = true;
251 IPC_BEGIN_MESSAGE_MAP(ChildProcessHostImpl, msg)
252 IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ShutdownRequest,
253 OnShutdownRequest)
254 IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateSharedMemory,
255 OnAllocateSharedMemory)
256 IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer,
257 OnAllocateGpuMemoryBuffer)
258 IPC_MESSAGE_UNHANDLED(handled = false)
259 IPC_END_MESSAGE_MAP()
260
261 if (!handled)
262 handled = delegate_->OnMessageReceived(msg);
263 }
264
265 #ifdef IPC_MESSAGE_LOG_ENABLED
266 if (logger->Enabled())
267 logger->OnPostDispatchMessage(msg, channel_id_);
268 #endif
269 return handled;
270 }
271
OnChannelConnected(int32 peer_pid)272 void ChildProcessHostImpl::OnChannelConnected(int32 peer_pid) {
273 if (!peer_handle_ &&
274 !base::OpenPrivilegedProcessHandle(peer_pid, &peer_handle_)) {
275 peer_handle_ = delegate_->GetHandle();
276 DCHECK(peer_handle_);
277 }
278 opening_channel_ = false;
279 delegate_->OnChannelConnected(peer_pid);
280 for (size_t i = 0; i < filters_.size(); ++i)
281 filters_[i]->OnChannelConnected(peer_pid);
282 }
283
OnChannelError()284 void ChildProcessHostImpl::OnChannelError() {
285 opening_channel_ = false;
286 delegate_->OnChannelError();
287
288 for (size_t i = 0; i < filters_.size(); ++i)
289 filters_[i]->OnChannelError();
290
291 // This will delete host_, which will also destroy this!
292 delegate_->OnChildDisconnected();
293 }
294
OnBadMessageReceived(const IPC::Message & message)295 void ChildProcessHostImpl::OnBadMessageReceived(const IPC::Message& message) {
296 delegate_->OnBadMessageReceived(message);
297 }
298
OnAllocateSharedMemory(uint32 buffer_size,base::SharedMemoryHandle * handle)299 void ChildProcessHostImpl::OnAllocateSharedMemory(
300 uint32 buffer_size,
301 base::SharedMemoryHandle* handle) {
302 AllocateSharedMemory(buffer_size, peer_handle_, handle);
303 }
304
OnShutdownRequest()305 void ChildProcessHostImpl::OnShutdownRequest() {
306 if (delegate_->CanShutdown())
307 Send(new ChildProcessMsg_Shutdown());
308 }
309
OnAllocateGpuMemoryBuffer(uint32 width,uint32 height,uint32 internalformat,uint32 usage,gfx::GpuMemoryBufferHandle * handle)310 void ChildProcessHostImpl::OnAllocateGpuMemoryBuffer(
311 uint32 width,
312 uint32 height,
313 uint32 internalformat,
314 uint32 usage,
315 gfx::GpuMemoryBufferHandle* handle) {
316 handle->type = gfx::SHARED_MEMORY_BUFFER;
317 AllocateSharedMemory(
318 width * height * GpuMemoryBufferImpl::BytesPerPixel(internalformat),
319 peer_handle_,
320 &handle->handle);
321 }
322
323 } // namespace content
324