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1 // Copyright 2013 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 "mojo/system/raw_channel.h" | |
6 | |
7 #include <errno.h> | |
8 #include <sys/uio.h> | |
9 #include <unistd.h> | |
10 | |
11 #include <algorithm> | |
12 #include <deque> | |
13 | |
14 #include "base/bind.h" | |
15 #include "base/location.h" | |
16 #include "base/logging.h" | |
17 #include "base/macros.h" | |
18 #include "base/memory/scoped_ptr.h" | |
19 #include "base/memory/weak_ptr.h" | |
20 #include "base/message_loop/message_loop.h" | |
21 #include "base/synchronization/lock.h" | |
22 #include "mojo/embedder/platform_channel_utils_posix.h" | |
23 #include "mojo/embedder/platform_handle.h" | |
24 #include "mojo/embedder/platform_handle_vector.h" | |
25 #include "mojo/system/transport_data.h" | |
26 | |
27 namespace mojo { | |
28 namespace system { | |
29 | |
30 namespace { | |
31 | |
32 class RawChannelPosix : public RawChannel, | |
33 public base::MessageLoopForIO::Watcher { | |
34 public: | |
35 explicit RawChannelPosix(embedder::ScopedPlatformHandle handle); | |
36 virtual ~RawChannelPosix(); | |
37 | |
38 // |RawChannel| public methods: | |
39 virtual size_t GetSerializedPlatformHandleSize() const override; | |
40 | |
41 private: | |
42 // |RawChannel| protected methods: | |
43 // Actually override this so that we can send multiple messages with (only) | |
44 // FDs if necessary. | |
45 virtual void EnqueueMessageNoLock( | |
46 scoped_ptr<MessageInTransit> message) override; | |
47 // Override this to handle those extra FD-only messages. | |
48 virtual bool OnReadMessageForRawChannel( | |
49 const MessageInTransit::View& message_view) override; | |
50 virtual IOResult Read(size_t* bytes_read) override; | |
51 virtual IOResult ScheduleRead() override; | |
52 virtual embedder::ScopedPlatformHandleVectorPtr GetReadPlatformHandles( | |
53 size_t num_platform_handles, | |
54 const void* platform_handle_table) override; | |
55 virtual IOResult WriteNoLock(size_t* platform_handles_written, | |
56 size_t* bytes_written) override; | |
57 virtual IOResult ScheduleWriteNoLock() override; | |
58 virtual bool OnInit() override; | |
59 virtual void OnShutdownNoLock(scoped_ptr<ReadBuffer> read_buffer, | |
60 scoped_ptr<WriteBuffer> write_buffer) override; | |
61 | |
62 // |base::MessageLoopForIO::Watcher| implementation: | |
63 virtual void OnFileCanReadWithoutBlocking(int fd) override; | |
64 virtual void OnFileCanWriteWithoutBlocking(int fd) override; | |
65 | |
66 // Implements most of |Read()| (except for a bit of clean-up): | |
67 IOResult ReadImpl(size_t* bytes_read); | |
68 | |
69 // Watches for |fd_| to become writable. Must be called on the I/O thread. | |
70 void WaitToWrite(); | |
71 | |
72 embedder::ScopedPlatformHandle fd_; | |
73 | |
74 // The following members are only used on the I/O thread: | |
75 scoped_ptr<base::MessageLoopForIO::FileDescriptorWatcher> read_watcher_; | |
76 scoped_ptr<base::MessageLoopForIO::FileDescriptorWatcher> write_watcher_; | |
77 | |
78 bool pending_read_; | |
79 | |
80 std::deque<embedder::PlatformHandle> read_platform_handles_; | |
81 | |
82 // The following members are used on multiple threads and protected by | |
83 // |write_lock()|: | |
84 bool pending_write_; | |
85 | |
86 // This is used for posting tasks from write threads to the I/O thread. It | |
87 // must only be accessed under |write_lock_|. The weak pointers it produces | |
88 // are only used/invalidated on the I/O thread. | |
89 base::WeakPtrFactory<RawChannelPosix> weak_ptr_factory_; | |
90 | |
91 DISALLOW_COPY_AND_ASSIGN(RawChannelPosix); | |
92 }; | |
93 | |
94 RawChannelPosix::RawChannelPosix(embedder::ScopedPlatformHandle handle) | |
95 : fd_(handle.Pass()), | |
96 pending_read_(false), | |
97 pending_write_(false), | |
98 weak_ptr_factory_(this) { | |
99 DCHECK(fd_.is_valid()); | |
100 } | |
101 | |
102 RawChannelPosix::~RawChannelPosix() { | |
103 DCHECK(!pending_read_); | |
104 DCHECK(!pending_write_); | |
105 | |
106 // No need to take the |write_lock()| here -- if there are still weak pointers | |
107 // outstanding, then we're hosed anyway (since we wouldn't be able to | |
108 // invalidate them cleanly, since we might not be on the I/O thread). | |
109 DCHECK(!weak_ptr_factory_.HasWeakPtrs()); | |
110 | |
111 // These must have been shut down/destroyed on the I/O thread. | |
112 DCHECK(!read_watcher_); | |
113 DCHECK(!write_watcher_); | |
114 | |
115 embedder::CloseAllPlatformHandles(&read_platform_handles_); | |
116 } | |
117 | |
118 size_t RawChannelPosix::GetSerializedPlatformHandleSize() const { | |
119 // We don't actually need any space on POSIX (since we just send FDs). | |
120 return 0; | |
121 } | |
122 | |
123 void RawChannelPosix::EnqueueMessageNoLock( | |
124 scoped_ptr<MessageInTransit> message) { | |
125 if (message->transport_data()) { | |
126 embedder::PlatformHandleVector* const platform_handles = | |
127 message->transport_data()->platform_handles(); | |
128 if (platform_handles && | |
129 platform_handles->size() > embedder::kPlatformChannelMaxNumHandles) { | |
130 // We can't attach all the FDs to a single message, so we have to "split" | |
131 // the message. Send as many control messages as needed first with FDs | |
132 // attached (and no data). | |
133 size_t i = 0; | |
134 for (; platform_handles->size() - i > | |
135 embedder::kPlatformChannelMaxNumHandles; | |
136 i += embedder::kPlatformChannelMaxNumHandles) { | |
137 scoped_ptr<MessageInTransit> fd_message(new MessageInTransit( | |
138 MessageInTransit::kTypeRawChannel, | |
139 MessageInTransit::kSubtypeRawChannelPosixExtraPlatformHandles, | |
140 0, | |
141 nullptr)); | |
142 embedder::ScopedPlatformHandleVectorPtr fds( | |
143 new embedder::PlatformHandleVector( | |
144 platform_handles->begin() + i, | |
145 platform_handles->begin() + i + | |
146 embedder::kPlatformChannelMaxNumHandles)); | |
147 fd_message->SetTransportData( | |
148 make_scoped_ptr(new TransportData(fds.Pass()))); | |
149 RawChannel::EnqueueMessageNoLock(fd_message.Pass()); | |
150 } | |
151 | |
152 // Remove the handles that we "moved" into the other messages. | |
153 platform_handles->erase(platform_handles->begin(), | |
154 platform_handles->begin() + i); | |
155 } | |
156 } | |
157 | |
158 RawChannel::EnqueueMessageNoLock(message.Pass()); | |
159 } | |
160 | |
161 bool RawChannelPosix::OnReadMessageForRawChannel( | |
162 const MessageInTransit::View& message_view) { | |
163 DCHECK_EQ(message_view.type(), MessageInTransit::kTypeRawChannel); | |
164 | |
165 if (message_view.subtype() == | |
166 MessageInTransit::kSubtypeRawChannelPosixExtraPlatformHandles) { | |
167 // We don't need to do anything. |RawChannel| won't extract the platform | |
168 // handles, and they'll be accumulated in |Read()|. | |
169 return true; | |
170 } | |
171 | |
172 return RawChannel::OnReadMessageForRawChannel(message_view); | |
173 } | |
174 | |
175 RawChannel::IOResult RawChannelPosix::Read(size_t* bytes_read) { | |
176 DCHECK_EQ(base::MessageLoop::current(), message_loop_for_io()); | |
177 DCHECK(!pending_read_); | |
178 | |
179 IOResult rv = ReadImpl(bytes_read); | |
180 if (rv != IO_SUCCEEDED && rv != IO_PENDING) { | |
181 // Make sure that |OnFileCanReadWithoutBlocking()| won't be called again. | |
182 read_watcher_.reset(); | |
183 } | |
184 return rv; | |
185 } | |
186 | |
187 RawChannel::IOResult RawChannelPosix::ScheduleRead() { | |
188 DCHECK_EQ(base::MessageLoop::current(), message_loop_for_io()); | |
189 DCHECK(!pending_read_); | |
190 | |
191 pending_read_ = true; | |
192 | |
193 return IO_PENDING; | |
194 } | |
195 | |
196 embedder::ScopedPlatformHandleVectorPtr RawChannelPosix::GetReadPlatformHandles( | |
197 size_t num_platform_handles, | |
198 const void* /*platform_handle_table*/) { | |
199 DCHECK_GT(num_platform_handles, 0u); | |
200 | |
201 if (read_platform_handles_.size() < num_platform_handles) { | |
202 embedder::CloseAllPlatformHandles(&read_platform_handles_); | |
203 read_platform_handles_.clear(); | |
204 return embedder::ScopedPlatformHandleVectorPtr(); | |
205 } | |
206 | |
207 embedder::ScopedPlatformHandleVectorPtr rv( | |
208 new embedder::PlatformHandleVector(num_platform_handles)); | |
209 rv->assign(read_platform_handles_.begin(), | |
210 read_platform_handles_.begin() + num_platform_handles); | |
211 read_platform_handles_.erase( | |
212 read_platform_handles_.begin(), | |
213 read_platform_handles_.begin() + num_platform_handles); | |
214 return rv.Pass(); | |
215 } | |
216 | |
217 RawChannel::IOResult RawChannelPosix::WriteNoLock( | |
218 size_t* platform_handles_written, | |
219 size_t* bytes_written) { | |
220 write_lock().AssertAcquired(); | |
221 | |
222 DCHECK(!pending_write_); | |
223 | |
224 size_t num_platform_handles = 0; | |
225 ssize_t write_result; | |
226 if (write_buffer_no_lock()->HavePlatformHandlesToSend()) { | |
227 embedder::PlatformHandle* platform_handles; | |
228 void* serialization_data; // Actually unused. | |
229 write_buffer_no_lock()->GetPlatformHandlesToSend( | |
230 &num_platform_handles, &platform_handles, &serialization_data); | |
231 DCHECK_GT(num_platform_handles, 0u); | |
232 DCHECK_LE(num_platform_handles, embedder::kPlatformChannelMaxNumHandles); | |
233 DCHECK(platform_handles); | |
234 | |
235 // TODO(vtl): Reduce code duplication. (This is duplicated from below.) | |
236 std::vector<WriteBuffer::Buffer> buffers; | |
237 write_buffer_no_lock()->GetBuffers(&buffers); | |
238 DCHECK(!buffers.empty()); | |
239 const size_t kMaxBufferCount = 10; | |
240 iovec iov[kMaxBufferCount]; | |
241 size_t buffer_count = std::min(buffers.size(), kMaxBufferCount); | |
242 for (size_t i = 0; i < buffer_count; ++i) { | |
243 iov[i].iov_base = const_cast<char*>(buffers[i].addr); | |
244 iov[i].iov_len = buffers[i].size; | |
245 } | |
246 | |
247 write_result = embedder::PlatformChannelSendmsgWithHandles( | |
248 fd_.get(), iov, buffer_count, platform_handles, num_platform_handles); | |
249 for (size_t i = 0; i < num_platform_handles; i++) | |
250 platform_handles[i].CloseIfNecessary(); | |
251 } else { | |
252 std::vector<WriteBuffer::Buffer> buffers; | |
253 write_buffer_no_lock()->GetBuffers(&buffers); | |
254 DCHECK(!buffers.empty()); | |
255 | |
256 if (buffers.size() == 1) { | |
257 write_result = embedder::PlatformChannelWrite( | |
258 fd_.get(), buffers[0].addr, buffers[0].size); | |
259 } else { | |
260 const size_t kMaxBufferCount = 10; | |
261 iovec iov[kMaxBufferCount]; | |
262 size_t buffer_count = std::min(buffers.size(), kMaxBufferCount); | |
263 for (size_t i = 0; i < buffer_count; ++i) { | |
264 iov[i].iov_base = const_cast<char*>(buffers[i].addr); | |
265 iov[i].iov_len = buffers[i].size; | |
266 } | |
267 | |
268 write_result = | |
269 embedder::PlatformChannelWritev(fd_.get(), iov, buffer_count); | |
270 } | |
271 } | |
272 | |
273 if (write_result >= 0) { | |
274 *platform_handles_written = num_platform_handles; | |
275 *bytes_written = static_cast<size_t>(write_result); | |
276 return IO_SUCCEEDED; | |
277 } | |
278 | |
279 if (errno == EPIPE) | |
280 return IO_FAILED_SHUTDOWN; | |
281 | |
282 if (errno != EAGAIN && errno != EWOULDBLOCK) { | |
283 PLOG(WARNING) << "sendmsg/write/writev"; | |
284 return IO_FAILED_UNKNOWN; | |
285 } | |
286 | |
287 return ScheduleWriteNoLock(); | |
288 } | |
289 | |
290 RawChannel::IOResult RawChannelPosix::ScheduleWriteNoLock() { | |
291 write_lock().AssertAcquired(); | |
292 | |
293 DCHECK(!pending_write_); | |
294 | |
295 // Set up to wait for the FD to become writable. | |
296 // If we're not on the I/O thread, we have to post a task to do this. | |
297 if (base::MessageLoop::current() != message_loop_for_io()) { | |
298 message_loop_for_io()->PostTask(FROM_HERE, | |
299 base::Bind(&RawChannelPosix::WaitToWrite, | |
300 weak_ptr_factory_.GetWeakPtr())); | |
301 pending_write_ = true; | |
302 return IO_PENDING; | |
303 } | |
304 | |
305 if (message_loop_for_io()->WatchFileDescriptor( | |
306 fd_.get().fd, | |
307 false, | |
308 base::MessageLoopForIO::WATCH_WRITE, | |
309 write_watcher_.get(), | |
310 this)) { | |
311 pending_write_ = true; | |
312 return IO_PENDING; | |
313 } | |
314 | |
315 return IO_FAILED_UNKNOWN; | |
316 } | |
317 | |
318 bool RawChannelPosix::OnInit() { | |
319 DCHECK_EQ(base::MessageLoop::current(), message_loop_for_io()); | |
320 | |
321 DCHECK(!read_watcher_); | |
322 read_watcher_.reset(new base::MessageLoopForIO::FileDescriptorWatcher()); | |
323 DCHECK(!write_watcher_); | |
324 write_watcher_.reset(new base::MessageLoopForIO::FileDescriptorWatcher()); | |
325 | |
326 if (!message_loop_for_io()->WatchFileDescriptor( | |
327 fd_.get().fd, | |
328 true, | |
329 base::MessageLoopForIO::WATCH_READ, | |
330 read_watcher_.get(), | |
331 this)) { | |
332 // TODO(vtl): I'm not sure |WatchFileDescriptor()| actually fails cleanly | |
333 // (in the sense of returning the message loop's state to what it was before | |
334 // it was called). | |
335 read_watcher_.reset(); | |
336 write_watcher_.reset(); | |
337 return false; | |
338 } | |
339 | |
340 return true; | |
341 } | |
342 | |
343 void RawChannelPosix::OnShutdownNoLock( | |
344 scoped_ptr<ReadBuffer> /*read_buffer*/, | |
345 scoped_ptr<WriteBuffer> /*write_buffer*/) { | |
346 DCHECK_EQ(base::MessageLoop::current(), message_loop_for_io()); | |
347 write_lock().AssertAcquired(); | |
348 | |
349 read_watcher_.reset(); // This will stop watching (if necessary). | |
350 write_watcher_.reset(); // This will stop watching (if necessary). | |
351 | |
352 pending_read_ = false; | |
353 pending_write_ = false; | |
354 | |
355 DCHECK(fd_.is_valid()); | |
356 fd_.reset(); | |
357 | |
358 weak_ptr_factory_.InvalidateWeakPtrs(); | |
359 } | |
360 | |
361 void RawChannelPosix::OnFileCanReadWithoutBlocking(int fd) { | |
362 DCHECK_EQ(fd, fd_.get().fd); | |
363 DCHECK_EQ(base::MessageLoop::current(), message_loop_for_io()); | |
364 | |
365 if (!pending_read_) { | |
366 NOTREACHED(); | |
367 return; | |
368 } | |
369 | |
370 pending_read_ = false; | |
371 size_t bytes_read = 0; | |
372 IOResult io_result = Read(&bytes_read); | |
373 if (io_result != IO_PENDING) | |
374 OnReadCompleted(io_result, bytes_read); | |
375 | |
376 // On failure, |read_watcher_| must have been reset; on success, | |
377 // we assume that |OnReadCompleted()| always schedules another read. | |
378 // Otherwise, we could end up spinning -- getting | |
379 // |OnFileCanReadWithoutBlocking()| again and again but not doing any actual | |
380 // read. | |
381 // TODO(yzshen): An alternative is to stop watching if RawChannel doesn't | |
382 // schedule a new read. But that code won't be reached under the current | |
383 // RawChannel implementation. | |
384 DCHECK(!read_watcher_ || pending_read_); | |
385 } | |
386 | |
387 void RawChannelPosix::OnFileCanWriteWithoutBlocking(int fd) { | |
388 DCHECK_EQ(fd, fd_.get().fd); | |
389 DCHECK_EQ(base::MessageLoop::current(), message_loop_for_io()); | |
390 | |
391 IOResult io_result; | |
392 size_t platform_handles_written = 0; | |
393 size_t bytes_written = 0; | |
394 { | |
395 base::AutoLock locker(write_lock()); | |
396 | |
397 DCHECK(pending_write_); | |
398 | |
399 pending_write_ = false; | |
400 io_result = WriteNoLock(&platform_handles_written, &bytes_written); | |
401 } | |
402 | |
403 if (io_result != IO_PENDING) | |
404 OnWriteCompleted(io_result, platform_handles_written, bytes_written); | |
405 } | |
406 | |
407 RawChannel::IOResult RawChannelPosix::ReadImpl(size_t* bytes_read) { | |
408 char* buffer = nullptr; | |
409 size_t bytes_to_read = 0; | |
410 read_buffer()->GetBuffer(&buffer, &bytes_to_read); | |
411 | |
412 size_t old_num_platform_handles = read_platform_handles_.size(); | |
413 ssize_t read_result = embedder::PlatformChannelRecvmsg( | |
414 fd_.get(), buffer, bytes_to_read, &read_platform_handles_); | |
415 if (read_platform_handles_.size() > old_num_platform_handles) { | |
416 DCHECK_LE(read_platform_handles_.size() - old_num_platform_handles, | |
417 embedder::kPlatformChannelMaxNumHandles); | |
418 | |
419 // We should never accumulate more than |TransportData::kMaxPlatformHandles | |
420 // + embedder::kPlatformChannelMaxNumHandles| handles. (The latter part is | |
421 // possible because we could have accumulated all the handles for a message, | |
422 // then received the message data plus the first set of handles for the next | |
423 // message in the subsequent |recvmsg()|.) | |
424 if (read_platform_handles_.size() > | |
425 (TransportData::kMaxPlatformHandles + | |
426 embedder::kPlatformChannelMaxNumHandles)) { | |
427 LOG(ERROR) << "Received too many platform handles"; | |
428 embedder::CloseAllPlatformHandles(&read_platform_handles_); | |
429 read_platform_handles_.clear(); | |
430 return IO_FAILED_UNKNOWN; | |
431 } | |
432 } | |
433 | |
434 if (read_result > 0) { | |
435 *bytes_read = static_cast<size_t>(read_result); | |
436 return IO_SUCCEEDED; | |
437 } | |
438 | |
439 // |read_result == 0| means "end of file". | |
440 if (read_result == 0) | |
441 return IO_FAILED_SHUTDOWN; | |
442 | |
443 if (errno == EAGAIN || errno == EWOULDBLOCK) | |
444 return ScheduleRead(); | |
445 | |
446 if (errno == ECONNRESET) | |
447 return IO_FAILED_BROKEN; | |
448 | |
449 PLOG(WARNING) << "recvmsg"; | |
450 return IO_FAILED_UNKNOWN; | |
451 } | |
452 | |
453 void RawChannelPosix::WaitToWrite() { | |
454 DCHECK_EQ(base::MessageLoop::current(), message_loop_for_io()); | |
455 | |
456 DCHECK(write_watcher_); | |
457 | |
458 if (!message_loop_for_io()->WatchFileDescriptor( | |
459 fd_.get().fd, | |
460 false, | |
461 base::MessageLoopForIO::WATCH_WRITE, | |
462 write_watcher_.get(), | |
463 this)) { | |
464 { | |
465 base::AutoLock locker(write_lock()); | |
466 | |
467 DCHECK(pending_write_); | |
468 pending_write_ = false; | |
469 } | |
470 OnWriteCompleted(IO_FAILED_UNKNOWN, 0, 0); | |
471 } | |
472 } | |
473 | |
474 } // namespace | |
475 | |
476 // ----------------------------------------------------------------------------- | |
477 | |
478 // Static factory method declared in raw_channel.h. | |
479 // static | |
480 scoped_ptr<RawChannel> RawChannel::Create( | |
481 embedder::ScopedPlatformHandle handle) { | |
482 return make_scoped_ptr(new RawChannelPosix(handle.Pass())); | |
483 } | |
484 | |
485 } // namespace system | |
486 } // namespace mojo | |
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