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.
5 #include "ipc/ipc_channel_posix.h"
10 #include <sys/socket.h>
12 #include <sys/types.h>
16 #if defined(OS_OPENBSD)
23 #include "base/command_line.h"
24 #include "base/files/file_path.h"
25 #include "base/files/file_util.h"
26 #include "base/location.h"
27 #include "base/logging.h"
28 #include "base/memory/scoped_ptr.h"
29 #include "base/memory/singleton.h"
30 #include "base/posix/eintr_wrapper.h"
31 #include "base/posix/global_descriptors.h"
32 #include "base/process/process_handle.h"
33 #include "base/rand_util.h"
34 #include "base/stl_util.h"
35 #include "base/strings/string_util.h"
36 #include "base/synchronization/lock.h"
37 #include "ipc/file_descriptor_set_posix.h"
38 #include "ipc/ipc_descriptors.h"
39 #include "ipc/ipc_listener.h"
40 #include "ipc/ipc_logging.h"
41 #include "ipc/ipc_message_utils.h"
42 #include "ipc/ipc_switches.h"
43 #include "ipc/unix_domain_socket_util.h"
47 // IPC channels on Windows use named pipes (CreateNamedPipe()) with
48 // channel ids as the pipe names. Channels on POSIX use sockets as
49 // pipes These don't quite line up.
51 // When creating a child subprocess we use a socket pair and the parent side of
52 // the fork arranges it such that the initial control channel ends up on the
53 // magic file descriptor kPrimaryIPCChannel in the child. Future
54 // connections (file descriptors) can then be passed via that
55 // connection via sendmsg().
57 // A POSIX IPC channel can also be set up as a server for a bound UNIX domain
58 // socket, and will handle multiple connect and disconnect sequences. Currently
59 // it is limited to one connection at a time.
61 //------------------------------------------------------------------------------
64 // The PipeMap class works around this quirk related to unit tests:
66 // When running as a server, we install the client socket in a
67 // specific file descriptor number (@kPrimaryIPCChannel). However, we
68 // also have to support the case where we are running unittests in the
69 // same process. (We do not support forking without execing.)
71 // Case 1: normal running
72 // The IPC server object will install a mapping in PipeMap from the
73 // name which it was given to the client pipe. When forking the client, the
74 // GetClientFileDescriptorMapping will ensure that the socket is installed in
75 // the magic slot (@kPrimaryIPCChannel). The client will search for the
76 // mapping, but it won't find any since we are in a new process. Thus the
77 // magic fd number is returned. Once the client connects, the server will
78 // close its copy of the client socket and remove the mapping.
80 // Case 2: unittests - client and server in the same process
81 // The IPC server will install a mapping as before. The client will search
82 // for a mapping and find out. It duplicates the file descriptor and
83 // connects. Once the client connects, the server will close the original
84 // copy of the client socket and remove the mapping. Thus, when the client
85 // object closes, it will close the only remaining copy of the client socket
86 // in the fd table and the server will see EOF on its side.
88 // TODO(port): a client process cannot connect to multiple IPC channels with
93 static PipeMap
* GetInstance() {
94 return Singleton
<PipeMap
>::get();
98 // Shouldn't have left over pipes.
102 // Lookup a given channel id. Return -1 if not found.
103 int Lookup(const std::string
& channel_id
) {
104 base::AutoLock
locked(lock_
);
106 ChannelToFDMap::const_iterator i
= map_
.find(channel_id
);
112 // Remove the mapping for the given channel id. No error is signaled if the
113 // channel_id doesn't exist
114 void Remove(const std::string
& channel_id
) {
115 base::AutoLock
locked(lock_
);
116 map_
.erase(channel_id
);
119 // Insert a mapping from @channel_id to @fd. It's a fatal error to insert a
120 // mapping if one already exists for the given channel_id
121 void Insert(const std::string
& channel_id
, int fd
) {
122 base::AutoLock
locked(lock_
);
125 ChannelToFDMap::const_iterator i
= map_
.find(channel_id
);
126 CHECK(i
== map_
.end()) << "Creating second IPC server (fd " << fd
<< ") "
127 << "for '" << channel_id
<< "' while first "
128 << "(fd " << i
->second
<< ") still exists";
129 map_
[channel_id
] = fd
;
134 typedef std::map
<std::string
, int> ChannelToFDMap
;
137 friend struct DefaultSingletonTraits
<PipeMap
>;
138 #if defined(OS_ANDROID)
139 friend void ::IPC::Channel::NotifyProcessForkedForTesting();
143 //------------------------------------------------------------------------------
145 bool SocketWriteErrorIsRecoverable() {
146 #if defined(OS_MACOSX)
147 // On OS X if sendmsg() is trying to send fds between processes and there
148 // isn't enough room in the output buffer to send the fd structure over
149 // atomically then EMSGSIZE is returned.
151 // EMSGSIZE presents a problem since the system APIs can only call us when
152 // there's room in the socket buffer and not when there is "enough" room.
154 // The current behavior is to return to the event loop when EMSGSIZE is
155 // received and hopefull service another FD. This is however still
156 // technically a busy wait since the event loop will call us right back until
157 // the receiver has read enough data to allow passing the FD over atomically.
158 return errno
== EAGAIN
|| errno
== EMSGSIZE
;
160 return errno
== EAGAIN
;
166 #if defined(OS_ANDROID)
167 // When we fork for simple tests on Android, we can't 'exec', so we need to
168 // reset these entries manually to get the expected testing behavior.
169 void Channel::NotifyProcessForkedForTesting() {
170 PipeMap::GetInstance()->map_
.clear();
174 //------------------------------------------------------------------------------
176 #if defined(OS_LINUX)
177 int ChannelPosix::global_pid_
= 0;
180 ChannelPosix::ChannelPosix(const IPC::ChannelHandle
& channel_handle
,
181 Mode mode
, Listener
* listener
)
182 : ChannelReader(listener
),
184 peer_pid_(base::kNullProcessId
),
185 is_blocked_on_write_(false),
186 waiting_connect_(true),
187 message_send_bytes_written_(0),
188 pipe_name_(channel_handle
.name
),
189 must_unlink_(false) {
190 memset(input_cmsg_buf_
, 0, sizeof(input_cmsg_buf_
));
191 if (!CreatePipe(channel_handle
)) {
192 // The pipe may have been closed already.
193 const char *modestr
= (mode_
& MODE_SERVER_FLAG
) ? "server" : "client";
194 LOG(WARNING
) << "Unable to create pipe named \"" << channel_handle
.name
195 << "\" in " << modestr
<< " mode";
199 ChannelPosix::~ChannelPosix() {
203 bool SocketPair(int* fd1
, int* fd2
) {
205 if (socketpair(AF_UNIX
, SOCK_STREAM
, 0, pipe_fds
) != 0) {
206 PLOG(ERROR
) << "socketpair()";
210 // Set both ends to be non-blocking.
211 if (fcntl(pipe_fds
[0], F_SETFL
, O_NONBLOCK
) == -1 ||
212 fcntl(pipe_fds
[1], F_SETFL
, O_NONBLOCK
) == -1) {
213 PLOG(ERROR
) << "fcntl(O_NONBLOCK)";
214 if (IGNORE_EINTR(close(pipe_fds
[0])) < 0)
215 PLOG(ERROR
) << "close";
216 if (IGNORE_EINTR(close(pipe_fds
[1])) < 0)
217 PLOG(ERROR
) << "close";
227 bool ChannelPosix::CreatePipe(
228 const IPC::ChannelHandle
& channel_handle
) {
229 DCHECK(!server_listen_pipe_
.is_valid() && !pipe_
.is_valid());
231 // Four possible cases:
232 // 1) It's a channel wrapping a pipe that is given to us.
233 // 2) It's for a named channel, so we create it.
234 // 3) It's for a client that we implement ourself. This is used
235 // in single-process unittesting.
236 // 4) It's the initial IPC channel:
237 // 4a) Client side: Pull the pipe out of the GlobalDescriptors set.
238 // 4b) Server side: create the pipe.
240 base::ScopedFD local_pipe
;
241 if (channel_handle
.socket
.fd
!= -1) {
242 // Case 1 from comment above.
243 local_pipe
.reset(channel_handle
.socket
.fd
);
244 #if defined(IPC_USES_READWRITE)
245 // Test the socket passed into us to make sure it is nonblocking.
246 // We don't want to call read/write on a blocking socket.
247 int value
= fcntl(local_pipe
.get(), F_GETFL
);
249 PLOG(ERROR
) << "fcntl(F_GETFL) " << pipe_name_
;
252 if (!(value
& O_NONBLOCK
)) {
253 LOG(ERROR
) << "Socket " << pipe_name_
<< " must be O_NONBLOCK";
256 #endif // IPC_USES_READWRITE
257 } else if (mode_
& MODE_NAMED_FLAG
) {
258 // Case 2 from comment above.
259 int local_pipe_fd
= -1;
261 if (mode_
& MODE_SERVER_FLAG
) {
262 if (!CreateServerUnixDomainSocket(base::FilePath(pipe_name_
),
268 } else if (mode_
& MODE_CLIENT_FLAG
) {
269 if (!CreateClientUnixDomainSocket(base::FilePath(pipe_name_
),
274 LOG(ERROR
) << "Bad mode: " << mode_
;
278 local_pipe
.reset(local_pipe_fd
);
280 local_pipe
.reset(PipeMap::GetInstance()->Lookup(pipe_name_
));
281 if (mode_
& MODE_CLIENT_FLAG
) {
282 if (local_pipe
.is_valid()) {
283 // Case 3 from comment above.
284 // We only allow one connection.
285 local_pipe
.reset(HANDLE_EINTR(dup(local_pipe
.release())));
286 PipeMap::GetInstance()->Remove(pipe_name_
);
288 // Case 4a from comment above.
289 // Guard against inappropriate reuse of the initial IPC channel. If
290 // an IPC channel closes and someone attempts to reuse it by name, the
291 // initial channel must not be recycled here. http://crbug.com/26754.
292 static bool used_initial_channel
= false;
293 if (used_initial_channel
) {
294 LOG(FATAL
) << "Denying attempt to reuse initial IPC channel for "
298 used_initial_channel
= true;
301 base::GlobalDescriptors::GetInstance()->Get(kPrimaryIPCChannel
));
303 } else if (mode_
& MODE_SERVER_FLAG
) {
304 // Case 4b from comment above.
305 if (local_pipe
.is_valid()) {
306 LOG(ERROR
) << "Server already exists for " << pipe_name_
;
307 // This is a client side pipe registered by other server and
308 // shouldn't be closed.
309 ignore_result(local_pipe
.release());
312 base::AutoLock
lock(client_pipe_lock_
);
313 int local_pipe_fd
= -1, client_pipe_fd
= -1;
314 if (!SocketPair(&local_pipe_fd
, &client_pipe_fd
))
316 local_pipe
.reset(local_pipe_fd
);
317 client_pipe_
.reset(client_pipe_fd
);
318 PipeMap::GetInstance()->Insert(pipe_name_
, client_pipe_fd
);
320 LOG(ERROR
) << "Bad mode: " << mode_
;
325 #if defined(IPC_USES_READWRITE)
326 // Create a dedicated socketpair() for exchanging file descriptors.
327 // See comments for IPC_USES_READWRITE for details.
328 if (mode_
& MODE_CLIENT_FLAG
) {
329 int fd_pipe_fd
= 1, remote_fd_pipe_fd
= -1;
330 if (!SocketPair(&fd_pipe_fd
, &remote_fd_pipe_fd
)) {
334 fd_pipe_
.reset(fd_pipe_fd
);
335 remote_fd_pipe_
.reset(remote_fd_pipe_fd
);
337 #endif // IPC_USES_READWRITE
339 if ((mode_
& MODE_SERVER_FLAG
) && (mode_
& MODE_NAMED_FLAG
))
340 server_listen_pipe_
.reset(local_pipe
.release());
342 pipe_
.reset(local_pipe
.release());
346 bool ChannelPosix::Connect() {
347 if (!server_listen_pipe_
.is_valid() && !pipe_
.is_valid()) {
348 DLOG(WARNING
) << "Channel creation failed: " << pipe_name_
;
352 bool did_connect
= true;
353 if (server_listen_pipe_
.is_valid()) {
354 // Watch the pipe for connections, and turn any connections into
356 base::MessageLoopForIO::current()->WatchFileDescriptor(
357 server_listen_pipe_
.get(),
359 base::MessageLoopForIO::WATCH_READ
,
360 &server_listen_connection_watcher_
,
363 did_connect
= AcceptConnection();
368 void ChannelPosix::CloseFileDescriptors(Message
* msg
) {
369 #if defined(OS_MACOSX)
370 // There is a bug on OSX which makes it dangerous to close
371 // a file descriptor while it is in transit. So instead we
372 // store the file descriptor in a set and send a message to
373 // the recipient, which is queued AFTER the message that
374 // sent the FD. The recipient will reply to the message,
375 // letting us know that it is now safe to close the file
376 // descriptor. For more information, see:
377 // http://crbug.com/298276
378 std::vector
<int> to_close
;
379 msg
->file_descriptor_set()->ReleaseFDsToClose(&to_close
);
380 for (size_t i
= 0; i
< to_close
.size(); i
++) {
381 fds_to_close_
.insert(to_close
[i
]);
382 QueueCloseFDMessage(to_close
[i
], 2);
385 msg
->file_descriptor_set()->CommitAll();
389 bool ChannelPosix::ProcessOutgoingMessages() {
390 DCHECK(!waiting_connect_
); // Why are we trying to send messages if there's
392 if (output_queue_
.empty())
395 if (!pipe_
.is_valid())
398 // Write out all the messages we can till the write blocks or there are no
399 // more outgoing messages.
400 while (!output_queue_
.empty()) {
401 Message
* msg
= output_queue_
.front();
403 size_t amt_to_write
= msg
->size() - message_send_bytes_written_
;
404 DCHECK_NE(0U, amt_to_write
);
405 const char* out_bytes
= reinterpret_cast<const char*>(msg
->data()) +
406 message_send_bytes_written_
;
408 struct msghdr msgh
= {0};
409 struct iovec iov
= {const_cast<char*>(out_bytes
), amt_to_write
};
413 sizeof(int) * FileDescriptorSet::kMaxDescriptorsPerMessage
)];
415 ssize_t bytes_written
= 1;
418 if (message_send_bytes_written_
== 0 &&
419 !msg
->file_descriptor_set()->empty()) {
420 // This is the first chunk of a message which has descriptors to send
421 struct cmsghdr
*cmsg
;
422 const unsigned num_fds
= msg
->file_descriptor_set()->size();
424 DCHECK(num_fds
<= FileDescriptorSet::kMaxDescriptorsPerMessage
);
425 if (msg
->file_descriptor_set()->ContainsDirectoryDescriptor()) {
426 LOG(FATAL
) << "Panic: attempting to transport directory descriptor over"
427 " IPC. Aborting to maintain sandbox isolation.";
428 // If you have hit this then something tried to send a file descriptor
429 // to a directory over an IPC channel. Since IPC channels span
430 // sandboxes this is very bad: the receiving process can use openat
431 // with ".." elements in the path in order to reach the real
435 msgh
.msg_control
= buf
;
436 msgh
.msg_controllen
= CMSG_SPACE(sizeof(int) * num_fds
);
437 cmsg
= CMSG_FIRSTHDR(&msgh
);
438 cmsg
->cmsg_level
= SOL_SOCKET
;
439 cmsg
->cmsg_type
= SCM_RIGHTS
;
440 cmsg
->cmsg_len
= CMSG_LEN(sizeof(int) * num_fds
);
441 msg
->file_descriptor_set()->PeekDescriptors(
442 reinterpret_cast<int*>(CMSG_DATA(cmsg
)));
443 msgh
.msg_controllen
= cmsg
->cmsg_len
;
445 // DCHECK_LE above already checks that
446 // num_fds < kMaxDescriptorsPerMessage so no danger of overflow.
447 msg
->header()->num_fds
= static_cast<uint16
>(num_fds
);
449 #if defined(IPC_USES_READWRITE)
450 if (!IsHelloMessage(*msg
)) {
451 // Only the Hello message sends the file descriptor with the message.
452 // Subsequently, we can send file descriptors on the dedicated
453 // fd_pipe_ which makes Seccomp sandbox operation more efficient.
454 struct iovec fd_pipe_iov
= { const_cast<char *>(""), 1 };
455 msgh
.msg_iov
= &fd_pipe_iov
;
456 fd_written
= fd_pipe_
.get();
458 HANDLE_EINTR(sendmsg(fd_pipe_
.get(), &msgh
, MSG_DONTWAIT
));
460 msgh
.msg_controllen
= 0;
461 if (bytes_written
> 0) {
462 CloseFileDescriptors(msg
);
465 #endif // IPC_USES_READWRITE
468 if (bytes_written
== 1) {
469 fd_written
= pipe_
.get();
470 #if defined(IPC_USES_READWRITE)
471 if ((mode_
& MODE_CLIENT_FLAG
) && IsHelloMessage(*msg
)) {
472 DCHECK_EQ(msg
->file_descriptor_set()->size(), 1U);
474 if (!msgh
.msg_controllen
) {
476 HANDLE_EINTR(write(pipe_
.get(), out_bytes
, amt_to_write
));
478 #endif // IPC_USES_READWRITE
480 bytes_written
= HANDLE_EINTR(sendmsg(pipe_
.get(), &msgh
, MSG_DONTWAIT
));
483 if (bytes_written
> 0)
484 CloseFileDescriptors(msg
);
486 if (bytes_written
< 0 && !SocketWriteErrorIsRecoverable()) {
487 // We can't close the pipe here, because calling OnChannelError
488 // may destroy this object, and that would be bad if we are
489 // called from Send(). Instead, we return false and hope the
490 // caller will close the pipe. If they do not, the pipe will
491 // still be closed next time OnFileCanReadWithoutBlocking is
493 #if defined(OS_MACOSX)
494 // On OSX writing to a pipe with no listener returns EPERM.
495 if (errno
== EPERM
) {
499 if (errno
== EPIPE
) {
502 PLOG(ERROR
) << "pipe error on "
504 << " Currently writing message of size: "
509 if (static_cast<size_t>(bytes_written
) != amt_to_write
) {
510 if (bytes_written
> 0) {
511 // If write() fails with EAGAIN then bytes_written will be -1.
512 message_send_bytes_written_
+= bytes_written
;
515 // Tell libevent to call us back once things are unblocked.
516 is_blocked_on_write_
= true;
517 base::MessageLoopForIO::current()->WatchFileDescriptor(
520 base::MessageLoopForIO::WATCH_WRITE
,
525 message_send_bytes_written_
= 0;
528 DVLOG(2) << "sent message @" << msg
<< " on channel @" << this
529 << " with type " << msg
->type() << " on fd " << pipe_
.get();
530 delete output_queue_
.front();
537 bool ChannelPosix::Send(Message
* message
) {
538 DVLOG(2) << "sending message @" << message
<< " on channel @" << this
539 << " with type " << message
->type()
540 << " (" << output_queue_
.size() << " in queue)";
542 #ifdef IPC_MESSAGE_LOG_ENABLED
543 Logging::GetInstance()->OnSendMessage(message
, "");
544 #endif // IPC_MESSAGE_LOG_ENABLED
546 message
->TraceMessageBegin();
547 output_queue_
.push(message
);
548 if (!is_blocked_on_write_
&& !waiting_connect_
) {
549 return ProcessOutgoingMessages();
555 int ChannelPosix::GetClientFileDescriptor() const {
556 base::AutoLock
lock(client_pipe_lock_
);
557 return client_pipe_
.get();
560 int ChannelPosix::TakeClientFileDescriptor() {
561 base::AutoLock
lock(client_pipe_lock_
);
562 if (!client_pipe_
.is_valid())
564 PipeMap::GetInstance()->Remove(pipe_name_
);
565 return client_pipe_
.release();
568 void ChannelPosix::CloseClientFileDescriptor() {
569 base::AutoLock
lock(client_pipe_lock_
);
570 if (!client_pipe_
.is_valid())
572 PipeMap::GetInstance()->Remove(pipe_name_
);
573 client_pipe_
.reset();
576 bool ChannelPosix::AcceptsConnections() const {
577 return server_listen_pipe_
.is_valid();
580 bool ChannelPosix::HasAcceptedConnection() const {
581 return AcceptsConnections() && pipe_
.is_valid();
584 bool ChannelPosix::GetPeerEuid(uid_t
* peer_euid
) const {
585 DCHECK(!(mode_
& MODE_SERVER
) || HasAcceptedConnection());
586 return IPC::GetPeerEuid(pipe_
.get(), peer_euid
);
589 void ChannelPosix::ResetToAcceptingConnectionState() {
590 // Unregister libevent for the unix domain socket and close it.
591 read_watcher_
.StopWatchingFileDescriptor();
592 write_watcher_
.StopWatchingFileDescriptor();
594 #if defined(IPC_USES_READWRITE)
596 remote_fd_pipe_
.reset();
597 #endif // IPC_USES_READWRITE
599 while (!output_queue_
.empty()) {
600 Message
* m
= output_queue_
.front();
605 // Close any outstanding, received file descriptors.
608 #if defined(OS_MACOSX)
609 // Clear any outstanding, sent file descriptors.
610 for (std::set
<int>::iterator i
= fds_to_close_
.begin();
611 i
!= fds_to_close_
.end();
613 if (IGNORE_EINTR(close(*i
)) < 0)
614 PLOG(ERROR
) << "close";
616 fds_to_close_
.clear();
621 bool ChannelPosix::IsNamedServerInitialized(
622 const std::string
& channel_id
) {
623 return base::PathExists(base::FilePath(channel_id
));
626 #if defined(OS_LINUX)
628 void ChannelPosix::SetGlobalPid(int pid
) {
633 // Called by libevent when we can read from the pipe without blocking.
634 void ChannelPosix::OnFileCanReadWithoutBlocking(int fd
) {
635 if (fd
== server_listen_pipe_
.get()) {
637 if (!ServerAcceptConnection(server_listen_pipe_
.get(), &new_pipe
) ||
640 listener()->OnChannelListenError();
643 if (pipe_
.is_valid()) {
644 // We already have a connection. We only handle one at a time.
645 // close our new descriptor.
646 if (HANDLE_EINTR(shutdown(new_pipe
, SHUT_RDWR
)) < 0)
647 DPLOG(ERROR
) << "shutdown " << pipe_name_
;
648 if (IGNORE_EINTR(close(new_pipe
)) < 0)
649 DPLOG(ERROR
) << "close " << pipe_name_
;
650 listener()->OnChannelDenied();
653 pipe_
.reset(new_pipe
);
655 if ((mode_
& MODE_OPEN_ACCESS_FLAG
) == 0) {
656 // Verify that the IPC channel peer is running as the same user.
658 if (!GetPeerEuid(&client_euid
)) {
659 DLOG(ERROR
) << "Unable to query client euid";
660 ResetToAcceptingConnectionState();
663 if (client_euid
!= geteuid()) {
664 DLOG(WARNING
) << "Client euid is not authorised";
665 ResetToAcceptingConnectionState();
670 if (!AcceptConnection()) {
671 NOTREACHED() << "AcceptConnection should not fail on server";
673 waiting_connect_
= false;
674 } else if (fd
== pipe_
) {
675 if (waiting_connect_
&& (mode_
& MODE_SERVER_FLAG
)) {
676 waiting_connect_
= false;
678 if (!ProcessIncomingMessages()) {
679 // ClosePipeOnError may delete this object, so we mustn't call
680 // ProcessOutgoingMessages.
685 NOTREACHED() << "Unknown pipe " << fd
;
688 // If we're a server and handshaking, then we want to make sure that we
689 // only send our handshake message after we've processed the client's.
690 // This gives us a chance to kill the client if the incoming handshake
691 // is invalid. This also flushes any closefd messages.
692 if (!is_blocked_on_write_
) {
693 if (!ProcessOutgoingMessages()) {
699 // Called by libevent when we can write to the pipe without blocking.
700 void ChannelPosix::OnFileCanWriteWithoutBlocking(int fd
) {
701 DCHECK_EQ(pipe_
.get(), fd
);
702 is_blocked_on_write_
= false;
703 if (!ProcessOutgoingMessages()) {
708 bool ChannelPosix::AcceptConnection() {
709 base::MessageLoopForIO::current()->WatchFileDescriptor(
712 base::MessageLoopForIO::WATCH_READ
,
717 if (mode_
& MODE_CLIENT_FLAG
) {
718 // If we are a client we want to send a hello message out immediately.
719 // In server mode we will send a hello message when we receive one from a
721 waiting_connect_
= false;
722 return ProcessOutgoingMessages();
723 } else if (mode_
& MODE_SERVER_FLAG
) {
724 waiting_connect_
= true;
732 void ChannelPosix::ClosePipeOnError() {
733 if (HasAcceptedConnection()) {
734 ResetToAcceptingConnectionState();
735 listener()->OnChannelError();
738 if (AcceptsConnections()) {
739 listener()->OnChannelListenError();
741 listener()->OnChannelError();
746 int ChannelPosix::GetHelloMessageProcId() const {
747 int pid
= base::GetCurrentProcId();
748 #if defined(OS_LINUX)
749 // Our process may be in a sandbox with a separate PID namespace.
757 void ChannelPosix::QueueHelloMessage() {
758 // Create the Hello message
759 scoped_ptr
<Message
> msg(new Message(MSG_ROUTING_NONE
,
761 IPC::Message::PRIORITY_NORMAL
));
762 if (!msg
->WriteInt(GetHelloMessageProcId())) {
763 NOTREACHED() << "Unable to pickle hello message proc id";
765 #if defined(IPC_USES_READWRITE)
766 scoped_ptr
<Message
> hello
;
767 if (remote_fd_pipe_
.is_valid()) {
768 if (!msg
->WriteBorrowingFile(remote_fd_pipe_
.get())) {
769 NOTREACHED() << "Unable to pickle hello message file descriptors";
771 DCHECK_EQ(msg
->file_descriptor_set()->size(), 1U);
773 #endif // IPC_USES_READWRITE
774 output_queue_
.push(msg
.release());
777 ChannelPosix::ReadState
ChannelPosix::ReadData(
781 if (!pipe_
.is_valid())
784 struct msghdr msg
= {0};
786 struct iovec iov
= {buffer
, static_cast<size_t>(buffer_len
)};
790 msg
.msg_control
= input_cmsg_buf_
;
792 // recvmsg() returns 0 if the connection has closed or EAGAIN if no data
793 // is waiting on the pipe.
794 #if defined(IPC_USES_READWRITE)
795 if (fd_pipe_
.is_valid()) {
796 *bytes_read
= HANDLE_EINTR(read(pipe_
.get(), buffer
, buffer_len
));
797 msg
.msg_controllen
= 0;
799 #endif // IPC_USES_READWRITE
801 msg
.msg_controllen
= sizeof(input_cmsg_buf_
);
802 *bytes_read
= HANDLE_EINTR(recvmsg(pipe_
.get(), &msg
, MSG_DONTWAIT
));
804 if (*bytes_read
< 0) {
805 if (errno
== EAGAIN
) {
807 #if defined(OS_MACOSX)
808 } else if (errno
== EPERM
) {
809 // On OSX, reading from a pipe with no listener returns EPERM
810 // treat this as a special case to prevent spurious error messages
814 } else if (errno
== ECONNRESET
|| errno
== EPIPE
) {
817 PLOG(ERROR
) << "pipe error (" << pipe_
.get() << ")";
820 } else if (*bytes_read
== 0) {
821 // The pipe has closed...
826 CloseClientFileDescriptor();
828 // Read any file descriptors from the message.
829 if (!ExtractFileDescriptorsFromMsghdr(&msg
))
831 return READ_SUCCEEDED
;
834 #if defined(IPC_USES_READWRITE)
835 bool ChannelPosix::ReadFileDescriptorsFromFDPipe() {
837 struct iovec fd_pipe_iov
= { &dummy
, 1 };
839 struct msghdr msg
= { 0 };
840 msg
.msg_iov
= &fd_pipe_iov
;
842 msg
.msg_control
= input_cmsg_buf_
;
843 msg
.msg_controllen
= sizeof(input_cmsg_buf_
);
844 ssize_t bytes_received
=
845 HANDLE_EINTR(recvmsg(fd_pipe_
.get(), &msg
, MSG_DONTWAIT
));
847 if (bytes_received
!= 1)
848 return true; // No message waiting.
850 if (!ExtractFileDescriptorsFromMsghdr(&msg
))
856 // On Posix, we need to fix up the file descriptors before the input message
859 // This will read from the input_fds_ (READWRITE mode only) and read more
860 // handles from the FD pipe if necessary.
861 bool ChannelPosix::WillDispatchInputMessage(Message
* msg
) {
862 uint16 header_fds
= msg
->header()->num_fds
;
864 return true; // Nothing to do.
866 // The message has file descriptors.
867 const char* error
= NULL
;
868 if (header_fds
> input_fds_
.size()) {
869 // The message has been completely received, but we didn't get
870 // enough file descriptors.
871 #if defined(IPC_USES_READWRITE)
872 if (!ReadFileDescriptorsFromFDPipe())
874 if (header_fds
> input_fds_
.size())
875 #endif // IPC_USES_READWRITE
876 error
= "Message needs unreceived descriptors";
879 if (header_fds
> FileDescriptorSet::kMaxDescriptorsPerMessage
)
880 error
= "Message requires an excessive number of descriptors";
883 LOG(WARNING
) << error
884 << " channel:" << this
885 << " message-type:" << msg
->type()
886 << " header()->num_fds:" << header_fds
;
887 // Abort the connection.
892 // The shenaniganery below with &foo.front() requires input_fds_ to have
893 // contiguous underlying storage (such as a simple array or a std::vector).
894 // This is why the header warns not to make input_fds_ a deque<>.
895 msg
->file_descriptor_set()->AddDescriptorsToOwn(&input_fds_
.front(),
897 input_fds_
.erase(input_fds_
.begin(), input_fds_
.begin() + header_fds
);
901 bool ChannelPosix::DidEmptyInputBuffers() {
902 // When the input data buffer is empty, the fds should be too. If this is
903 // not the case, we probably have a rogue renderer which is trying to fill
904 // our descriptor table.
905 return input_fds_
.empty();
908 bool ChannelPosix::ExtractFileDescriptorsFromMsghdr(msghdr
* msg
) {
909 // Check that there are any control messages. On OSX, CMSG_FIRSTHDR will
910 // return an invalid non-NULL pointer in the case that controllen == 0.
911 if (msg
->msg_controllen
== 0)
914 for (cmsghdr
* cmsg
= CMSG_FIRSTHDR(msg
);
916 cmsg
= CMSG_NXTHDR(msg
, cmsg
)) {
917 if (cmsg
->cmsg_level
== SOL_SOCKET
&& cmsg
->cmsg_type
== SCM_RIGHTS
) {
918 unsigned payload_len
= cmsg
->cmsg_len
- CMSG_LEN(0);
919 DCHECK_EQ(0U, payload_len
% sizeof(int));
920 const int* file_descriptors
= reinterpret_cast<int*>(CMSG_DATA(cmsg
));
921 unsigned num_file_descriptors
= payload_len
/ 4;
922 input_fds_
.insert(input_fds_
.end(),
924 file_descriptors
+ num_file_descriptors
);
926 // Check this after adding the FDs so we don't leak them.
927 if (msg
->msg_flags
& MSG_CTRUNC
) {
936 // No file descriptors found, but that's OK.
940 void ChannelPosix::ClearInputFDs() {
941 for (size_t i
= 0; i
< input_fds_
.size(); ++i
) {
942 if (IGNORE_EINTR(close(input_fds_
[i
])) < 0)
943 PLOG(ERROR
) << "close ";
948 void ChannelPosix::QueueCloseFDMessage(int fd
, int hops
) {
952 // Create the message
953 scoped_ptr
<Message
> msg(new Message(MSG_ROUTING_NONE
,
954 CLOSE_FD_MESSAGE_TYPE
,
955 IPC::Message::PRIORITY_NORMAL
));
956 if (!msg
->WriteInt(hops
- 1) || !msg
->WriteInt(fd
)) {
957 NOTREACHED() << "Unable to pickle close fd.";
959 // Send(msg.release());
960 output_queue_
.push(msg
.release());
970 void ChannelPosix::HandleInternalMessage(const Message
& msg
) {
971 // The Hello message contains only the process id.
972 PickleIterator
iter(msg
);
974 switch (msg
.type()) {
979 case Channel::HELLO_MESSAGE_TYPE
:
981 if (!msg
.ReadInt(&iter
, &pid
))
984 #if defined(IPC_USES_READWRITE)
985 if (mode_
& MODE_SERVER_FLAG
) {
986 // With IPC_USES_READWRITE, the Hello message from the client to the
987 // server also contains the fd_pipe_, which will be used for all
988 // subsequent file descriptor passing.
989 DCHECK_EQ(msg
.file_descriptor_set()->size(), 1U);
990 base::ScopedFD descriptor
;
991 if (!msg
.ReadFile(&iter
, &descriptor
)) {
994 fd_pipe_
.reset(descriptor
.release());
996 #endif // IPC_USES_READWRITE
998 listener()->OnChannelConnected(pid
);
1001 #if defined(OS_MACOSX)
1002 case Channel::CLOSE_FD_MESSAGE_TYPE
:
1004 if (!msg
.ReadInt(&iter
, &hops
))
1006 if (!msg
.ReadInt(&iter
, &fd
))
1009 if (fds_to_close_
.erase(fd
) > 0) {
1010 if (IGNORE_EINTR(close(fd
)) < 0)
1011 PLOG(ERROR
) << "close";
1016 QueueCloseFDMessage(fd
, hops
);
1023 void ChannelPosix::Close() {
1024 // Close can be called multiple time, so we need to make sure we're
1027 ResetToAcceptingConnectionState();
1030 unlink(pipe_name_
.c_str());
1031 must_unlink_
= false;
1034 if (server_listen_pipe_
.is_valid()) {
1035 server_listen_pipe_
.reset();
1036 // Unregister libevent for the listening socket and close it.
1037 server_listen_connection_watcher_
.StopWatchingFileDescriptor();
1040 CloseClientFileDescriptor();
1043 base::ProcessId
ChannelPosix::GetPeerPID() const {
1047 base::ProcessId
ChannelPosix::GetSelfPID() const {
1048 return GetHelloMessageProcId();
1051 //------------------------------------------------------------------------------
1052 // Channel's methods
1055 scoped_ptr
<Channel
> Channel::Create(
1056 const IPC::ChannelHandle
&channel_handle
, Mode mode
, Listener
* listener
) {
1057 return make_scoped_ptr(new ChannelPosix(channel_handle
, mode
, listener
));
1061 std::string
Channel::GenerateVerifiedChannelID(const std::string
& prefix
) {
1062 // A random name is sufficient validation on posix systems, so we don't need
1063 // an additional shared secret.
1065 std::string id
= prefix
;
1069 return id
.append(GenerateUniqueRandomChannelID());
1073 bool Channel::IsNamedServerInitialized(
1074 const std::string
& channel_id
) {
1075 return ChannelPosix::IsNamedServerInitialized(channel_id
);
1078 #if defined(OS_LINUX)
1080 void Channel::SetGlobalPid(int pid
) {
1081 ChannelPosix::SetGlobalPid(pid
);