ipc/ipc_channel_nacl.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 "ipc/ipc_channel_nacl.h"
   6
   7 #include <errno.h>
   8 #include <stddef.h>
   9 #include <stdint.h>
  10 #include <sys/types.h>
  11
  12 #include <algorithm>
  13
  14 #include "base/bind.h"
  15 #include "base/logging.h"
  16 #include "base/single_thread_task_runner.h"
  17 #include "base/synchronization/lock.h"
  18 #include "base/task_runner_util.h"
  19 #include "base/thread_task_runner_handle.h"
  20 #include "base/threading/simple_thread.h"
  21 #include "ipc/ipc_listener.h"
  22 #include "ipc/ipc_logging.h"
  23 #include "ipc/ipc_message_attachment_set.h"
  24 #include "native_client/src/public/imc_syscalls.h"
  25 #include "native_client/src/public/imc_types.h"
  26
  27 namespace IPC {
  28
  29 struct MessageContents {
  30   std::vector<char> data;
  31   std::vector<int> fds;
  32 };
  33
  34 namespace {
  35
  36 bool ReadDataOnReaderThread(int pipe, MessageContents* contents) {
  37   DCHECK(pipe >= 0);
  38   if (pipe < 0)
  39     return false;
  40
  41   contents->data.resize(Channel::kReadBufferSize);
  42   contents->fds.resize(NACL_ABI_IMC_DESC_MAX);
  43
  44   NaClAbiNaClImcMsgIoVec iov = { &contents->data[0], contents->data.size() };
  45   NaClAbiNaClImcMsgHdr msg = {
  46     &iov, 1, &contents->fds[0], contents->fds.size()
  47   };
  48
  49   int bytes_read = imc_recvmsg(pipe, &msg, 0);
  50
  51   if (bytes_read <= 0) {
  52     // NaClIPCAdapter::BlockingReceive returns -1 when the pipe closes (either
  53     // due to error or for regular shutdown).
  54     contents->data.clear();
  55     contents->fds.clear();
  56     return false;
  57   }
  58   DCHECK(bytes_read);
  59   // Resize the buffers down to the number of bytes and fds we actually read.
  60   contents->data.resize(bytes_read);
  61   contents->fds.resize(msg.desc_length);
  62   return true;
  63 }
  64
  65 }  // namespace
  66
  67 class ChannelNacl::ReaderThreadRunner
  68     : public base::DelegateSimpleThread::Delegate {
  69  public:
  70   // |pipe|: A file descriptor from which we will read using imc_recvmsg.
  71   // |data_read_callback|: A callback we invoke (on the main thread) when we
  72   //                       have read data.
  73   // |failure_callback|: A callback we invoke when we have a failure reading
  74   //                     from |pipe|.
  75   // |main_message_loop|: A proxy for the main thread, where we will invoke the
  76   //                      above callbacks.
  77   ReaderThreadRunner(
  78       int pipe,
  79       base::Callback<void(scoped_ptr<MessageContents>)> data_read_callback,
  80       base::Callback<void()> failure_callback,
  81       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner);
  82
  83   // DelegateSimpleThread implementation. Reads data from the pipe in a loop
  84   // until either we are told to quit or a read fails.
  85   void Run() override;
  86
  87  private:
  88   int pipe_;
  89   base::Callback<void (scoped_ptr<MessageContents>)> data_read_callback_;
  90   base::Callback<void ()> failure_callback_;
  91   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
  92
  93   DISALLOW_COPY_AND_ASSIGN(ReaderThreadRunner);
  94 };
  95
  96 ChannelNacl::ReaderThreadRunner::ReaderThreadRunner(
  97     int pipe,
  98     base::Callback<void(scoped_ptr<MessageContents>)> data_read_callback,
  99     base::Callback<void()> failure_callback,
 100     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner)
 101     : pipe_(pipe),
 102       data_read_callback_(data_read_callback),
 103       failure_callback_(failure_callback),
 104       main_task_runner_(main_task_runner) {
 105 }
 106
 107 void ChannelNacl::ReaderThreadRunner::Run() {
 108   while (true) {
 109     scoped_ptr<MessageContents> msg_contents(new MessageContents);
 110     bool success = ReadDataOnReaderThread(pipe_, msg_contents.get());
 111     if (success) {
 112       main_task_runner_->PostTask(
 113           FROM_HERE,
 114           base::Bind(data_read_callback_, base::Passed(&msg_contents)));
 115     } else {
 116       main_task_runner_->PostTask(FROM_HERE, failure_callback_);
 117       // Because the read failed, we know we're going to quit. Don't bother
 118       // trying to read again.
 119       return;
 120     }
 121   }
 122 }
 123
 124 ChannelNacl::ChannelNacl(const IPC::ChannelHandle& channel_handle,
 125                          Mode mode,
 126                          Listener* listener,
 127                          AttachmentBroker* broker)
 128     : ChannelReader(listener),
 129       mode_(mode),
 130       waiting_connect_(true),
 131       pipe_(-1),
 132       pipe_name_(channel_handle.name),
 133       weak_ptr_factory_(this),
 134       broker_(broker) {
 135   if (!CreatePipe(channel_handle)) {
 136     // The pipe may have been closed already.
 137     const char *modestr = (mode_ & MODE_SERVER_FLAG) ? "server" : "client";
 138     LOG(WARNING) << "Unable to create pipe named \"" << channel_handle.name
 139                  << "\" in " << modestr << " mode";
 140   }
 141 }
 142
 143 ChannelNacl::~ChannelNacl() {
 144   Close();
 145 }
 146
 147 base::ProcessId ChannelNacl::GetPeerPID() const {
 148   // This shouldn't actually get used in the untrusted side of the proxy, and we
 149   // don't have the real pid anyway.
 150   return -1;
 151 }
 152
 153 base::ProcessId ChannelNacl::GetSelfPID() const {
 154   return -1;
 155 }
 156
 157 bool ChannelNacl::Connect() {
 158   if (pipe_ == -1) {
 159     DLOG(WARNING) << "Channel creation failed: " << pipe_name_;
 160     return false;
 161   }
 162
 163   // Note that Connect is called on the "Channel" thread (i.e., the same thread
 164   // where Channel::Send will be called, and the same thread that should receive
 165   // messages). The constructor might be invoked on another thread (see
 166   // ChannelProxy for an example of that). Therefore, we must wait until Connect
 167   // is called to decide which SingleThreadTaskRunner to pass to
 168   // ReaderThreadRunner.
 169   reader_thread_runner_.reset(new ReaderThreadRunner(
 170       pipe_,
 171       base::Bind(&ChannelNacl::DidRecvMsg, weak_ptr_factory_.GetWeakPtr()),
 172       base::Bind(&ChannelNacl::ReadDidFail, weak_ptr_factory_.GetWeakPtr()),
 173       base::ThreadTaskRunnerHandle::Get()));
 174   reader_thread_.reset(
 175       new base::DelegateSimpleThread(reader_thread_runner_.get(),
 176                                      "ipc_channel_nacl reader thread"));
 177   reader_thread_->Start();
 178   waiting_connect_ = false;
 179   // If there were any messages queued before connection, send them.
 180   ProcessOutgoingMessages();
 181   base::ThreadTaskRunnerHandle::Get()->PostTask(
 182       FROM_HERE, base::Bind(&ChannelNacl::CallOnChannelConnected,
 183                             weak_ptr_factory_.GetWeakPtr()));
 184
 185   return true;
 186 }
 187
 188 void ChannelNacl::Close() {
 189   // For now, we assume that at shutdown, the reader thread will be woken with
 190   // a failure (see NaClIPCAdapter::BlockingRead and CloseChannel). Or... we
 191   // might simply be killed with no chance to clean up anyway :-).
 192   // If untrusted code tries to close the channel prior to shutdown, it's likely
 193   // to hang.
 194   // TODO(dmichael): Can we do anything smarter here to make sure the reader
 195   //                 thread wakes up and quits?
 196   reader_thread_->Join();
 197   close(pipe_);
 198   pipe_ = -1;
 199   reader_thread_runner_.reset();
 200   reader_thread_.reset();
 201   read_queue_.clear();
 202   output_queue_.clear();
 203 }
 204
 205 bool ChannelNacl::Send(Message* message) {
 206   DCHECK(!message->HasAttachments());
 207   DVLOG(2) << "sending message @" << message << " on channel @" << this
 208            << " with type " << message->type();
 209   scoped_ptr<Message> message_ptr(message);
 210
 211 #ifdef IPC_MESSAGE_LOG_ENABLED
 212   Logging::GetInstance()->OnSendMessage(message_ptr.get(), "");
 213 #endif  // IPC_MESSAGE_LOG_ENABLED
 214
 215   TRACE_EVENT_WITH_FLOW0(TRACE_DISABLED_BY_DEFAULT("ipc.flow"),
 216                          "ChannelNacl::Send",
 217                          message->header()->flags,
 218                          TRACE_EVENT_FLAG_FLOW_OUT);
 219   output_queue_.push_back(linked_ptr<Message>(message_ptr.release()));
 220   if (!waiting_connect_)
 221     return ProcessOutgoingMessages();
 222
 223   return true;
 224 }
 225
 226 AttachmentBroker* ChannelNacl::GetAttachmentBroker() {
 227   return broker_;
 228 }
 229
 230 void ChannelNacl::DidRecvMsg(scoped_ptr<MessageContents> contents) {
 231   // Close sets the pipe to -1. It's possible we'll get a buffer sent to us from
 232   // the reader thread after Close is called. If so, we ignore it.
 233   if (pipe_ == -1)
 234     return;
 235
 236   linked_ptr<std::vector<char> > data(new std::vector<char>);
 237   data->swap(contents->data);
 238   read_queue_.push_back(data);
 239
 240   input_fds_.insert(input_fds_.end(),
 241                     contents->fds.begin(), contents->fds.end());
 242   contents->fds.clear();
 243
 244   // In POSIX, we would be told when there are bytes to read by implementing
 245   // OnFileCanReadWithoutBlocking in MessageLoopForIO::Watcher. In NaCl, we
 246   // instead know at this point because the reader thread posted some data to
 247   // us.
 248   ProcessIncomingMessages();
 249 }
 250
 251 void ChannelNacl::ReadDidFail() {
 252   Close();
 253 }
 254
 255 bool ChannelNacl::CreatePipe(
 256     const IPC::ChannelHandle& channel_handle) {
 257   DCHECK(pipe_ == -1);
 258
 259   // There's one possible case in NaCl:
 260   // 1) It's a channel wrapping a pipe that is given to us.
 261   // We don't support these:
 262   // 2) It's for a named channel.
 263   // 3) It's for a client that we implement ourself.
 264   // 4) It's the initial IPC channel.
 265
 266   if (channel_handle.socket.fd == -1) {
 267     NOTIMPLEMENTED();
 268     return false;
 269   }
 270   pipe_ = channel_handle.socket.fd;
 271   return true;
 272 }
 273
 274 bool ChannelNacl::ProcessOutgoingMessages() {
 275   DCHECK(!waiting_connect_);  // Why are we trying to send messages if there's
 276                               // no connection?
 277   if (output_queue_.empty())
 278     return true;
 279
 280   if (pipe_ == -1)
 281     return false;
 282
 283   // Write out all the messages. The trusted implementation is guaranteed to not
 284   // block. See NaClIPCAdapter::Send for the implementation of imc_sendmsg.
 285   while (!output_queue_.empty()) {
 286     linked_ptr<Message> msg = output_queue_.front();
 287     output_queue_.pop_front();
 288
 289     int fds[MessageAttachmentSet::kMaxDescriptorsPerMessage];
 290     const size_t num_fds = msg->attachment_set()->size();
 291     DCHECK(num_fds <= MessageAttachmentSet::kMaxDescriptorsPerMessage);
 292     msg->attachment_set()->PeekDescriptors(fds);
 293
 294     NaClAbiNaClImcMsgIoVec iov = {
 295       const_cast<void*>(msg->data()), msg->size()
 296     };
 297     NaClAbiNaClImcMsgHdr msgh = { &iov, 1, fds, num_fds };
 298     ssize_t bytes_written = imc_sendmsg(pipe_, &msgh, 0);
 299
 300     DCHECK(bytes_written);  // The trusted side shouldn't return 0.
 301     if (bytes_written < 0) {
 302       // The trusted side should only ever give us an error of EPIPE. We
 303       // should never be interrupted, nor should we get EAGAIN.
 304       DCHECK(errno == EPIPE);
 305       Close();
 306       PLOG(ERROR) << "pipe_ error on "
 307                   << pipe_
 308                   << " Currently writing message of size: "
 309                   << msg->size();
 310       return false;
 311     } else {
 312       msg->attachment_set()->CommitAll();
 313     }
 314
 315     // Message sent OK!
 316     DVLOG(2) << "sent message @" << msg.get() << " with type " << msg->type()
 317              << " on fd " << pipe_;
 318   }
 319   return true;
 320 }
 321
 322 void ChannelNacl::CallOnChannelConnected() {
 323   listener()->OnChannelConnected(GetPeerPID());
 324 }
 325
 326 ChannelNacl::ReadState ChannelNacl::ReadData(
 327     char* buffer,
 328     int buffer_len,
 329     int* bytes_read) {
 330   *bytes_read = 0;
 331   if (pipe_ == -1)
 332     return READ_FAILED;
 333   if (read_queue_.empty())
 334     return READ_PENDING;
 335   while (!read_queue_.empty() && *bytes_read < buffer_len) {
 336     linked_ptr<std::vector<char> > vec(read_queue_.front());
 337     size_t bytes_to_read = buffer_len - *bytes_read;
 338     if (vec->size() <= bytes_to_read) {
 339       // We can read and discard the entire vector.
 340       std::copy(vec->begin(), vec->end(), buffer + *bytes_read);
 341       *bytes_read += vec->size();
 342       read_queue_.pop_front();
 343     } else {
 344       // Read all the bytes we can and discard them from the front of the
 345       // vector. (This can be slowish, since erase has to move the back of the
 346       // vector to the front, but it's hopefully a temporary hack and it keeps
 347       // the code simple).
 348       std::copy(vec->begin(), vec->begin() + bytes_to_read,
 349                 buffer + *bytes_read);
 350       vec->erase(vec->begin(), vec->begin() + bytes_to_read);
 351       *bytes_read += bytes_to_read;
 352     }
 353   }
 354   return READ_SUCCEEDED;
 355 }
 356
 357 bool ChannelNacl::ShouldDispatchInputMessage(Message* msg) {
 358   return true;
 359 }
 360
 361 bool ChannelNacl::GetNonBrokeredAttachments(Message* msg) {
 362   uint16_t header_fds = msg->header()->num_fds;
 363   CHECK(header_fds == input_fds_.size());
 364   if (header_fds == 0)
 365     return true;  // Nothing to do.
 366
 367   // The shenaniganery below with &foo.front() requires input_fds_ to have
 368   // contiguous underlying storage (such as a simple array or a std::vector).
 369   // This is why the header warns not to make input_fds_ a deque<>.
 370   msg->attachment_set()->AddDescriptorsToOwn(&input_fds_.front(), header_fds);
 371   input_fds_.clear();
 372   return true;
 373 }
 374
 375 bool ChannelNacl::DidEmptyInputBuffers() {
 376   // When the input data buffer is empty, the fds should be too.
 377   return input_fds_.empty();
 378 }
 379
 380 void ChannelNacl::HandleInternalMessage(const Message& msg) {
 381   // The trusted side IPC::Channel should handle the "hello" handshake; we
 382   // should not receive the "Hello" message.
 383   NOTREACHED();
 384 }
 385
 386 base::ProcessId ChannelNacl::GetSenderPID() {
 387   // The untrusted side of the IPC::Channel should never have to worry about
 388   // sender's process id.
 389   return base::kNullProcessId;
 390 }
 391
 392 bool ChannelNacl::IsAttachmentBrokerEndpoint() {
 393   return is_attachment_broker_endpoint();
 394 }
 395
 396 // Channel's methods
 397
 398 // static
 399 scoped_ptr<Channel> Channel::Create(const IPC::ChannelHandle& channel_handle,
 400                                     Mode mode,
 401                                     Listener* listener,
 402                                     AttachmentBroker* broker) {
 403   return scoped_ptr<Channel>(
 404       new ChannelNacl(channel_handle, mode, listener, broker));
 405 }
 406
 407 }  // namespace IPC