ipc/mojo/ipc_message_pipe_reader.cc

   1 // Copyright 2014 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 "ipc/mojo/ipc_message_pipe_reader.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "base/location.h"
  10 #include "base/logging.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "base/thread_task_runner_handle.h"
  13 #include "ipc/mojo/async_handle_waiter.h"
  14 #include "ipc/mojo/ipc_channel_mojo.h"
  15
  16 namespace IPC {
  17 namespace internal {
  18
  19 MessagePipeReader::MessagePipeReader(mojo::ScopedMessagePipeHandle handle,
  20                                      MessagePipeReader::Delegate* delegate)
  21     : pipe_(handle.Pass()),
  22       delegate_(delegate),
  23       async_waiter_(
  24           new AsyncHandleWaiter(base::Bind(&MessagePipeReader::PipeIsReady,
  25                                            base::Unretained(this)))),
  26       pending_send_error_(MOJO_RESULT_OK) {
  27 }
  28
  29 MessagePipeReader::~MessagePipeReader() {
  30   // The pipe should be closed before deletion.
  31   CHECK(!IsValid());
  32   DCHECK_EQ(pending_send_error_, MOJO_RESULT_OK);
  33 }
  34
  35 void MessagePipeReader::Close() {
  36   // All pending errors should be signaled before Close().
  37   DCHECK_EQ(pending_send_error_, MOJO_RESULT_OK);
  38   async_waiter_.reset();
  39   pipe_.reset();
  40   OnPipeClosed();
  41 }
  42
  43 void MessagePipeReader::CloseWithError(MojoResult error) {
  44   OnPipeError(error);
  45   Close();
  46 }
  47
  48 void MessagePipeReader::CloseWithErrorIfPending() {
  49   if (pending_send_error_ == MOJO_RESULT_OK)
  50     return;
  51   MojoResult error = pending_send_error_;
  52   pending_send_error_ = MOJO_RESULT_OK;
  53   CloseWithError(error);
  54   return;
  55 }
  56
  57 void MessagePipeReader::CloseWithErrorLater(MojoResult error) {
  58   pending_send_error_ = error;
  59 }
  60
  61 bool MessagePipeReader::Send(scoped_ptr<Message> message) {
  62   DCHECK(IsValid());
  63
  64   message->TraceMessageBegin();
  65   std::vector<MojoHandle> handles;
  66   MojoResult result = MOJO_RESULT_OK;
  67   result = ChannelMojo::ReadFromMessageAttachmentSet(message.get(), &handles);
  68   if (result == MOJO_RESULT_OK) {
  69     result = MojoWriteMessage(handle(),
  70                               message->data(),
  71                               static_cast<uint32>(message->size()),
  72                               handles.empty() ? nullptr : &handles[0],
  73                               static_cast<uint32>(handles.size()),
  74                               MOJO_WRITE_MESSAGE_FLAG_NONE);
  75   }
  76
  77   if (result != MOJO_RESULT_OK) {
  78     std::for_each(handles.begin(), handles.end(), &MojoClose);
  79     // We cannot call CloseWithError() here as Send() is protected by
  80     // ChannelMojo's lock and CloseWithError() could re-enter ChannelMojo. We
  81     // cannot call CloseWithError() also because Send() can be called from
  82     // non-UI thread while OnPipeError() expects to be called on IO thread.
  83     CloseWithErrorLater(result);
  84     return false;
  85   }
  86
  87   return true;
  88 }
  89
  90 void MessagePipeReader::OnMessageReceived() {
  91   Message message(data_buffer().empty() ? "" : &data_buffer()[0],
  92                   static_cast<uint32>(data_buffer().size()));
  93
  94   std::vector<MojoHandle> handle_buffer;
  95   TakeHandleBuffer(&handle_buffer);
  96   MojoResult write_result =
  97       ChannelMojo::WriteToMessageAttachmentSet(handle_buffer, &message);
  98   if (write_result != MOJO_RESULT_OK) {
  99     CloseWithError(write_result);
 100     return;
 101   }
 102
 103   message.TraceMessageEnd();
 104   delegate_->OnMessageReceived(message);
 105 }
 106
 107 void MessagePipeReader::OnPipeClosed() {
 108   if (!delegate_)
 109     return;
 110   delegate_->OnPipeClosed(this);
 111   delegate_ = nullptr;
 112 }
 113
 114 void MessagePipeReader::OnPipeError(MojoResult error) {
 115   if (!delegate_)
 116     return;
 117   delegate_->OnPipeError(this);
 118 }
 119
 120 MojoResult MessagePipeReader::ReadMessageBytes() {
 121   DCHECK(handle_buffer_.empty());
 122
 123   uint32_t num_bytes = static_cast<uint32_t>(data_buffer_.size());
 124   uint32_t num_handles = 0;
 125   MojoResult result = MojoReadMessage(pipe_.get().value(),
 126                                       num_bytes ? &data_buffer_[0] : nullptr,
 127                                       &num_bytes,
 128                                       nullptr,
 129                                       &num_handles,
 130                                       MOJO_READ_MESSAGE_FLAG_NONE);
 131   data_buffer_.resize(num_bytes);
 132   handle_buffer_.resize(num_handles);
 133   if (result == MOJO_RESULT_RESOURCE_EXHAUSTED) {
 134     // MOJO_RESULT_RESOURCE_EXHAUSTED was asking the caller that
 135     // it needs more bufer. So we re-read it with resized buffers.
 136     result = MojoReadMessage(pipe_.get().value(),
 137                              num_bytes ? &data_buffer_[0] : nullptr,
 138                              &num_bytes,
 139                              num_handles ? &handle_buffer_[0] : nullptr,
 140                              &num_handles,
 141                              MOJO_READ_MESSAGE_FLAG_NONE);
 142   }
 143
 144   DCHECK(0 == num_bytes || data_buffer_.size() == num_bytes);
 145   DCHECK(0 == num_handles || handle_buffer_.size() == num_handles);
 146   return result;
 147 }
 148
 149 void MessagePipeReader::ReadAvailableMessages() {
 150   while (pipe_.is_valid()) {
 151     MojoResult read_result = ReadMessageBytes();
 152     if (read_result == MOJO_RESULT_SHOULD_WAIT)
 153       break;
 154     if (read_result != MOJO_RESULT_OK) {
 155       DLOG(WARNING)
 156           << "Pipe got error from ReadMessage(). Closing: " << read_result;
 157       OnPipeError(read_result);
 158       Close();
 159       break;
 160     }
 161
 162     OnMessageReceived();
 163   }
 164
 165 }
 166
 167 void MessagePipeReader::ReadMessagesThenWait() {
 168   while (true) {
 169     ReadAvailableMessages();
 170     if (!pipe_.is_valid())
 171       break;
 172     // |Wait()| is safe to call only after all messages are read.
 173     // If can fail with |MOJO_RESULT_ALREADY_EXISTS| otherwise.
 174     // Also, we don't use MOJO_HANDLE_SIGNAL_WRITABLE here, expecting buffer in
 175     // MessagePipe.
 176     MojoResult result =
 177         async_waiter_->Wait(pipe_.get().value(), MOJO_HANDLE_SIGNAL_READABLE);
 178     // If the result is |MOJO_RESULT_ALREADY_EXISTS|, there could be messages
 179     // that have been arrived after the last |ReadAvailableMessages()|.
 180     // We have to consume then and retry in that case.
 181     if (result != MOJO_RESULT_ALREADY_EXISTS) {
 182       if (result != MOJO_RESULT_OK) {
 183         LOG(ERROR) << "Failed to wait on the pipe. Result is " << result;
 184         OnPipeError(result);
 185         Close();
 186       }
 187
 188       break;
 189     }
 190   }
 191 }
 192
 193 void MessagePipeReader::PipeIsReady(MojoResult wait_result) {
 194   CloseWithErrorIfPending();
 195   if (!IsValid()) {
 196     // There was a pending error and it closed the pipe.
 197     // We cannot do the work anymore.
 198     return;
 199   }
 200
 201   if (wait_result != MOJO_RESULT_OK) {
 202     if (wait_result != MOJO_RESULT_ABORTED) {
 203       // FAILED_PRECONDITION happens every time the peer is dead so
 204       // it isn't worth polluting the log message.
 205       LOG_IF(WARNING, wait_result != MOJO_RESULT_FAILED_PRECONDITION)
 206           << "Pipe got error from the waiter. Closing: " << wait_result;
 207       OnPipeError(wait_result);
 208     }
 209
 210     Close();
 211     return;
 212   }
 213
 214   ReadMessagesThenWait();
 215 }
 216
 217 void MessagePipeReader::DelayedDeleter::operator()(
 218     MessagePipeReader* ptr) const {
 219   ptr->Close();
 220   base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
 221                                                 base::Bind(&DeleteNow, ptr));
 222 }
 223
 224 }  // namespace internal
 225 }  // namespace IPC