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/file_util.h"
25 #include "base/files/file_path.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_util.h"
33 #include "base/rand_util.h"
34 #include "base/stl_util.h"
35 #include "base/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
>;
140 //------------------------------------------------------------------------------
142 bool SocketWriteErrorIsRecoverable() {
143 #if defined(OS_MACOSX)
144 // On OS X if sendmsg() is trying to send fds between processes and there
145 // isn't enough room in the output buffer to send the fd structure over
146 // atomically then EMSGSIZE is returned.
148 // EMSGSIZE presents a problem since the system APIs can only call us when
149 // there's room in the socket buffer and not when there is "enough" room.
151 // The current behavior is to return to the event loop when EMSGSIZE is
152 // received and hopefull service another FD. This is however still
153 // technically a busy wait since the event loop will call us right back until
154 // the receiver has read enough data to allow passing the FD over atomically.
155 return errno
== EAGAIN
|| errno
== EMSGSIZE
;
157 return errno
== EAGAIN
;
162 //------------------------------------------------------------------------------
164 #if defined(OS_LINUX)
165 int Channel::ChannelImpl::global_pid_
= 0;
168 Channel::ChannelImpl::ChannelImpl(const IPC::ChannelHandle
& channel_handle
,
169 Mode mode
, Listener
* listener
)
170 : ChannelReader(listener
),
172 peer_pid_(base::kNullProcessId
),
173 is_blocked_on_write_(false),
174 waiting_connect_(true),
175 message_send_bytes_written_(0),
176 server_listen_pipe_(-1),
179 #if defined(IPC_USES_READWRITE)
182 #endif // IPC_USES_READWRITE
183 pipe_name_(channel_handle
.name
),
184 must_unlink_(false) {
185 memset(input_cmsg_buf_
, 0, sizeof(input_cmsg_buf_
));
186 if (!CreatePipe(channel_handle
)) {
187 // The pipe may have been closed already.
188 const char *modestr
= (mode_
& MODE_SERVER_FLAG
) ? "server" : "client";
189 LOG(WARNING
) << "Unable to create pipe named \"" << channel_handle
.name
190 << "\" in " << modestr
<< " mode";
194 Channel::ChannelImpl::~ChannelImpl() {
198 bool SocketPair(int* fd1
, int* fd2
) {
200 if (socketpair(AF_UNIX
, SOCK_STREAM
, 0, pipe_fds
) != 0) {
201 PLOG(ERROR
) << "socketpair()";
205 // Set both ends to be non-blocking.
206 if (fcntl(pipe_fds
[0], F_SETFL
, O_NONBLOCK
) == -1 ||
207 fcntl(pipe_fds
[1], F_SETFL
, O_NONBLOCK
) == -1) {
208 PLOG(ERROR
) << "fcntl(O_NONBLOCK)";
209 if (HANDLE_EINTR(close(pipe_fds
[0])) < 0)
210 PLOG(ERROR
) << "close";
211 if (HANDLE_EINTR(close(pipe_fds
[1])) < 0)
212 PLOG(ERROR
) << "close";
222 bool Channel::ChannelImpl::CreatePipe(
223 const IPC::ChannelHandle
& channel_handle
) {
224 DCHECK(server_listen_pipe_
== -1 && pipe_
== -1);
226 // Four possible cases:
227 // 1) It's a channel wrapping a pipe that is given to us.
228 // 2) It's for a named channel, so we create it.
229 // 3) It's for a client that we implement ourself. This is used
231 // 4) It's the initial IPC channel:
232 // 4a) Client side: Pull the pipe out of the GlobalDescriptors set.
233 // 4b) Server side: create the pipe.
236 if (channel_handle
.socket
.fd
!= -1) {
237 // Case 1 from comment above.
238 local_pipe
= channel_handle
.socket
.fd
;
239 #if defined(IPC_USES_READWRITE)
240 // Test the socket passed into us to make sure it is nonblocking.
241 // We don't want to call read/write on a blocking socket.
242 int value
= fcntl(local_pipe
, F_GETFL
);
244 PLOG(ERROR
) << "fcntl(F_GETFL) " << pipe_name_
;
247 if (!(value
& O_NONBLOCK
)) {
248 LOG(ERROR
) << "Socket " << pipe_name_
<< " must be O_NONBLOCK";
251 #endif // IPC_USES_READWRITE
252 } else if (mode_
& MODE_NAMED_FLAG
) {
253 // Case 2 from comment above.
254 if (mode_
& MODE_SERVER_FLAG
) {
255 if (!CreateServerUnixDomainSocket(base::FilePath(pipe_name_
),
260 } else if (mode_
& MODE_CLIENT_FLAG
) {
261 if (!CreateClientUnixDomainSocket(base::FilePath(pipe_name_
),
266 LOG(ERROR
) << "Bad mode: " << mode_
;
270 local_pipe
= PipeMap::GetInstance()->Lookup(pipe_name_
);
271 if (mode_
& MODE_CLIENT_FLAG
) {
272 if (local_pipe
!= -1) {
273 // Case 3 from comment above.
274 // We only allow one connection.
275 local_pipe
= HANDLE_EINTR(dup(local_pipe
));
276 PipeMap::GetInstance()->Remove(pipe_name_
);
278 // Case 4a from comment above.
279 // Guard against inappropriate reuse of the initial IPC channel. If
280 // an IPC channel closes and someone attempts to reuse it by name, the
281 // initial channel must not be recycled here. http://crbug.com/26754.
282 static bool used_initial_channel
= false;
283 if (used_initial_channel
) {
284 LOG(FATAL
) << "Denying attempt to reuse initial IPC channel for "
288 used_initial_channel
= true;
291 base::GlobalDescriptors::GetInstance()->Get(kPrimaryIPCChannel
);
293 } else if (mode_
& MODE_SERVER_FLAG
) {
294 // Case 4b from comment above.
295 if (local_pipe
!= -1) {
296 LOG(ERROR
) << "Server already exists for " << pipe_name_
;
299 base::AutoLock
lock(client_pipe_lock_
);
300 if (!SocketPair(&local_pipe
, &client_pipe_
))
302 PipeMap::GetInstance()->Insert(pipe_name_
, client_pipe_
);
304 LOG(ERROR
) << "Bad mode: " << mode_
;
309 #if defined(IPC_USES_READWRITE)
310 // Create a dedicated socketpair() for exchanging file descriptors.
311 // See comments for IPC_USES_READWRITE for details.
312 if (mode_
& MODE_CLIENT_FLAG
) {
313 if (!SocketPair(&fd_pipe_
, &remote_fd_pipe_
)) {
317 #endif // IPC_USES_READWRITE
319 if ((mode_
& MODE_SERVER_FLAG
) && (mode_
& MODE_NAMED_FLAG
)) {
320 server_listen_pipe_
= local_pipe
;
328 bool Channel::ChannelImpl::Connect() {
329 if (server_listen_pipe_
== -1 && pipe_
== -1) {
330 DLOG(INFO
) << "Channel creation failed: " << pipe_name_
;
334 bool did_connect
= true;
335 if (server_listen_pipe_
!= -1) {
336 // Watch the pipe for connections, and turn any connections into
338 MessageLoopForIO::current()->WatchFileDescriptor(
341 MessageLoopForIO::WATCH_READ
,
342 &server_listen_connection_watcher_
,
345 did_connect
= AcceptConnection();
350 bool Channel::ChannelImpl::ProcessOutgoingMessages() {
351 DCHECK(!waiting_connect_
); // Why are we trying to send messages if there's
353 if (output_queue_
.empty())
359 // Write out all the messages we can till the write blocks or there are no
360 // more outgoing messages.
361 while (!output_queue_
.empty()) {
362 Message
* msg
= output_queue_
.front();
364 size_t amt_to_write
= msg
->size() - message_send_bytes_written_
;
365 DCHECK_NE(0U, amt_to_write
);
366 const char* out_bytes
= reinterpret_cast<const char*>(msg
->data()) +
367 message_send_bytes_written_
;
369 struct msghdr msgh
= {0};
370 struct iovec iov
= {const_cast<char*>(out_bytes
), amt_to_write
};
374 sizeof(int) * FileDescriptorSet::kMaxDescriptorsPerMessage
)];
376 ssize_t bytes_written
= 1;
379 if (message_send_bytes_written_
== 0 &&
380 !msg
->file_descriptor_set()->empty()) {
381 // This is the first chunk of a message which has descriptors to send
382 struct cmsghdr
*cmsg
;
383 const unsigned num_fds
= msg
->file_descriptor_set()->size();
385 DCHECK(num_fds
<= FileDescriptorSet::kMaxDescriptorsPerMessage
);
386 if (msg
->file_descriptor_set()->ContainsDirectoryDescriptor()) {
387 LOG(FATAL
) << "Panic: attempting to transport directory descriptor over"
388 " IPC. Aborting to maintain sandbox isolation.";
389 // If you have hit this then something tried to send a file descriptor
390 // to a directory over an IPC channel. Since IPC channels span
391 // sandboxes this is very bad: the receiving process can use openat
392 // with ".." elements in the path in order to reach the real
396 msgh
.msg_control
= buf
;
397 msgh
.msg_controllen
= CMSG_SPACE(sizeof(int) * num_fds
);
398 cmsg
= CMSG_FIRSTHDR(&msgh
);
399 cmsg
->cmsg_level
= SOL_SOCKET
;
400 cmsg
->cmsg_type
= SCM_RIGHTS
;
401 cmsg
->cmsg_len
= CMSG_LEN(sizeof(int) * num_fds
);
402 msg
->file_descriptor_set()->GetDescriptors(
403 reinterpret_cast<int*>(CMSG_DATA(cmsg
)));
404 msgh
.msg_controllen
= cmsg
->cmsg_len
;
406 // DCHECK_LE above already checks that
407 // num_fds < kMaxDescriptorsPerMessage so no danger of overflow.
408 msg
->header()->num_fds
= static_cast<uint16
>(num_fds
);
410 #if defined(IPC_USES_READWRITE)
411 if (!IsHelloMessage(*msg
)) {
412 // Only the Hello message sends the file descriptor with the message.
413 // Subsequently, we can send file descriptors on the dedicated
414 // fd_pipe_ which makes Seccomp sandbox operation more efficient.
415 struct iovec fd_pipe_iov
= { const_cast<char *>(""), 1 };
416 msgh
.msg_iov
= &fd_pipe_iov
;
417 fd_written
= fd_pipe_
;
418 bytes_written
= HANDLE_EINTR(sendmsg(fd_pipe_
, &msgh
, MSG_DONTWAIT
));
420 msgh
.msg_controllen
= 0;
421 if (bytes_written
> 0) {
422 msg
->file_descriptor_set()->CommitAll();
425 #endif // IPC_USES_READWRITE
428 if (bytes_written
== 1) {
430 #if defined(IPC_USES_READWRITE)
431 if ((mode_
& MODE_CLIENT_FLAG
) && IsHelloMessage(*msg
)) {
432 DCHECK_EQ(msg
->file_descriptor_set()->size(), 1U);
434 if (!msgh
.msg_controllen
) {
435 bytes_written
= HANDLE_EINTR(write(pipe_
, out_bytes
, amt_to_write
));
437 #endif // IPC_USES_READWRITE
439 bytes_written
= HANDLE_EINTR(sendmsg(pipe_
, &msgh
, MSG_DONTWAIT
));
442 if (bytes_written
> 0)
443 msg
->file_descriptor_set()->CommitAll();
445 if (bytes_written
< 0 && !SocketWriteErrorIsRecoverable()) {
446 #if defined(OS_MACOSX)
447 // On OSX writing to a pipe with no listener returns EPERM.
448 if (errno
== EPERM
) {
453 if (errno
== EPIPE
) {
457 PLOG(ERROR
) << "pipe error on "
459 << " Currently writing message of size: "
464 if (static_cast<size_t>(bytes_written
) != amt_to_write
) {
465 if (bytes_written
> 0) {
466 // If write() fails with EAGAIN then bytes_written will be -1.
467 message_send_bytes_written_
+= bytes_written
;
470 // Tell libevent to call us back once things are unblocked.
471 is_blocked_on_write_
= true;
472 MessageLoopForIO::current()->WatchFileDescriptor(
475 MessageLoopForIO::WATCH_WRITE
,
480 message_send_bytes_written_
= 0;
483 DVLOG(2) << "sent message @" << msg
<< " on channel @" << this
484 << " with type " << msg
->type() << " on fd " << pipe_
;
485 delete output_queue_
.front();
492 bool Channel::ChannelImpl::Send(Message
* message
) {
493 DVLOG(2) << "sending message @" << message
<< " on channel @" << this
494 << " with type " << message
->type()
495 << " (" << output_queue_
.size() << " in queue)";
497 #ifdef IPC_MESSAGE_LOG_ENABLED
498 Logging::GetInstance()->OnSendMessage(message
, "");
499 #endif // IPC_MESSAGE_LOG_ENABLED
501 message
->TraceMessageBegin();
502 output_queue_
.push(message
);
503 if (!is_blocked_on_write_
&& !waiting_connect_
) {
504 return ProcessOutgoingMessages();
510 int Channel::ChannelImpl::GetClientFileDescriptor() {
511 base::AutoLock
lock(client_pipe_lock_
);
515 int Channel::ChannelImpl::TakeClientFileDescriptor() {
516 base::AutoLock
lock(client_pipe_lock_
);
517 int fd
= client_pipe_
;
518 if (client_pipe_
!= -1) {
519 PipeMap::GetInstance()->Remove(pipe_name_
);
525 void Channel::ChannelImpl::CloseClientFileDescriptor() {
526 base::AutoLock
lock(client_pipe_lock_
);
527 if (client_pipe_
!= -1) {
528 PipeMap::GetInstance()->Remove(pipe_name_
);
529 if (HANDLE_EINTR(close(client_pipe_
)) < 0)
530 PLOG(ERROR
) << "close " << pipe_name_
;
535 bool Channel::ChannelImpl::AcceptsConnections() const {
536 return server_listen_pipe_
!= -1;
539 bool Channel::ChannelImpl::HasAcceptedConnection() const {
540 return AcceptsConnections() && pipe_
!= -1;
543 bool Channel::ChannelImpl::GetPeerEuid(uid_t
* peer_euid
) const {
544 DCHECK(!(mode_
& MODE_SERVER
) || HasAcceptedConnection());
545 return IPC::GetPeerEuid(pipe_
, peer_euid
);
548 void Channel::ChannelImpl::ResetToAcceptingConnectionState() {
549 // Unregister libevent for the unix domain socket and close it.
550 read_watcher_
.StopWatchingFileDescriptor();
551 write_watcher_
.StopWatchingFileDescriptor();
553 if (HANDLE_EINTR(close(pipe_
)) < 0)
554 PLOG(ERROR
) << "close pipe_ " << pipe_name_
;
557 #if defined(IPC_USES_READWRITE)
558 if (fd_pipe_
!= -1) {
559 if (HANDLE_EINTR(close(fd_pipe_
)) < 0)
560 PLOG(ERROR
) << "close fd_pipe_ " << pipe_name_
;
563 if (remote_fd_pipe_
!= -1) {
564 if (HANDLE_EINTR(close(remote_fd_pipe_
)) < 0)
565 PLOG(ERROR
) << "close remote_fd_pipe_ " << pipe_name_
;
566 remote_fd_pipe_
= -1;
568 #endif // IPC_USES_READWRITE
570 while (!output_queue_
.empty()) {
571 Message
* m
= output_queue_
.front();
576 // Close any outstanding, received file descriptors.
581 bool Channel::ChannelImpl::IsNamedServerInitialized(
582 const std::string
& channel_id
) {
583 return file_util::PathExists(base::FilePath(channel_id
));
586 #if defined(OS_LINUX)
588 void Channel::ChannelImpl::SetGlobalPid(int pid
) {
593 // Called by libevent when we can read from the pipe without blocking.
594 void Channel::ChannelImpl::OnFileCanReadWithoutBlocking(int fd
) {
595 bool send_server_hello_msg
= false;
596 if (fd
== server_listen_pipe_
) {
598 if (!ServerAcceptConnection(server_listen_pipe_
, &new_pipe
) ||
601 listener()->OnChannelListenError();
605 // We already have a connection. We only handle one at a time.
606 // close our new descriptor.
607 if (HANDLE_EINTR(shutdown(new_pipe
, SHUT_RDWR
)) < 0)
608 DPLOG(ERROR
) << "shutdown " << pipe_name_
;
609 if (HANDLE_EINTR(close(new_pipe
)) < 0)
610 DPLOG(ERROR
) << "close " << pipe_name_
;
611 listener()->OnChannelDenied();
616 if ((mode_
& MODE_OPEN_ACCESS_FLAG
) == 0) {
617 // Verify that the IPC channel peer is running as the same user.
619 if (!GetPeerEuid(&client_euid
)) {
620 DLOG(ERROR
) << "Unable to query client euid";
621 ResetToAcceptingConnectionState();
624 if (client_euid
!= geteuid()) {
625 DLOG(WARNING
) << "Client euid is not authorised";
626 ResetToAcceptingConnectionState();
631 if (!AcceptConnection()) {
632 NOTREACHED() << "AcceptConnection should not fail on server";
634 send_server_hello_msg
= true;
635 waiting_connect_
= false;
636 } else if (fd
== pipe_
) {
637 if (waiting_connect_
&& (mode_
& MODE_SERVER_FLAG
)) {
638 send_server_hello_msg
= true;
639 waiting_connect_
= false;
641 if (!ProcessIncomingMessages()) {
642 // ClosePipeOnError may delete this object, so we mustn't call
643 // ProcessOutgoingMessages.
644 send_server_hello_msg
= false;
648 NOTREACHED() << "Unknown pipe " << fd
;
651 // If we're a server and handshaking, then we want to make sure that we
652 // only send our handshake message after we've processed the client's.
653 // This gives us a chance to kill the client if the incoming handshake
655 if (send_server_hello_msg
) {
656 ProcessOutgoingMessages();
660 // Called by libevent when we can write to the pipe without blocking.
661 void Channel::ChannelImpl::OnFileCanWriteWithoutBlocking(int fd
) {
662 DCHECK_EQ(pipe_
, fd
);
663 is_blocked_on_write_
= false;
664 if (!ProcessOutgoingMessages()) {
669 bool Channel::ChannelImpl::AcceptConnection() {
670 MessageLoopForIO::current()->WatchFileDescriptor(pipe_
,
672 MessageLoopForIO::WATCH_READ
,
677 if (mode_
& MODE_CLIENT_FLAG
) {
678 // If we are a client we want to send a hello message out immediately.
679 // In server mode we will send a hello message when we receive one from a
681 waiting_connect_
= false;
682 return ProcessOutgoingMessages();
683 } else if (mode_
& MODE_SERVER_FLAG
) {
684 waiting_connect_
= true;
692 void Channel::ChannelImpl::ClosePipeOnError() {
693 if (HasAcceptedConnection()) {
694 ResetToAcceptingConnectionState();
695 listener()->OnChannelError();
698 if (AcceptsConnections()) {
699 listener()->OnChannelListenError();
701 listener()->OnChannelError();
706 int Channel::ChannelImpl::GetHelloMessageProcId() {
707 int pid
= base::GetCurrentProcId();
708 #if defined(OS_LINUX)
709 // Our process may be in a sandbox with a separate PID namespace.
717 void Channel::ChannelImpl::QueueHelloMessage() {
718 // Create the Hello message
719 scoped_ptr
<Message
> msg(new Message(MSG_ROUTING_NONE
,
721 IPC::Message::PRIORITY_NORMAL
));
722 if (!msg
->WriteInt(GetHelloMessageProcId())) {
723 NOTREACHED() << "Unable to pickle hello message proc id";
725 #if defined(IPC_USES_READWRITE)
726 scoped_ptr
<Message
> hello
;
727 if (remote_fd_pipe_
!= -1) {
728 if (!msg
->WriteFileDescriptor(base::FileDescriptor(remote_fd_pipe_
,
730 NOTREACHED() << "Unable to pickle hello message file descriptors";
732 DCHECK_EQ(msg
->file_descriptor_set()->size(), 1U);
734 #endif // IPC_USES_READWRITE
735 output_queue_
.push(msg
.release());
738 Channel::ChannelImpl::ReadState
Channel::ChannelImpl::ReadData(
745 struct msghdr msg
= {0};
747 struct iovec iov
= {buffer
, static_cast<size_t>(buffer_len
)};
751 msg
.msg_control
= input_cmsg_buf_
;
753 // recvmsg() returns 0 if the connection has closed or EAGAIN if no data
754 // is waiting on the pipe.
755 #if defined(IPC_USES_READWRITE)
757 *bytes_read
= HANDLE_EINTR(read(pipe_
, buffer
, buffer_len
));
758 msg
.msg_controllen
= 0;
760 #endif // IPC_USES_READWRITE
762 msg
.msg_controllen
= sizeof(input_cmsg_buf_
);
763 *bytes_read
= HANDLE_EINTR(recvmsg(pipe_
, &msg
, MSG_DONTWAIT
));
765 if (*bytes_read
< 0) {
766 if (errno
== EAGAIN
) {
768 #if defined(OS_MACOSX)
769 } else if (errno
== EPERM
) {
770 // On OSX, reading from a pipe with no listener returns EPERM
771 // treat this as a special case to prevent spurious error messages
775 } else if (errno
== ECONNRESET
|| errno
== EPIPE
) {
778 PLOG(ERROR
) << "pipe error (" << pipe_
<< ")";
781 } else if (*bytes_read
== 0) {
782 // The pipe has closed...
787 CloseClientFileDescriptor();
789 // Read any file descriptors from the message.
790 if (!ExtractFileDescriptorsFromMsghdr(&msg
))
792 return READ_SUCCEEDED
;
795 #if defined(IPC_USES_READWRITE)
796 bool Channel::ChannelImpl::ReadFileDescriptorsFromFDPipe() {
798 struct iovec fd_pipe_iov
= { &dummy
, 1 };
800 struct msghdr msg
= { 0 };
801 msg
.msg_iov
= &fd_pipe_iov
;
803 msg
.msg_control
= input_cmsg_buf_
;
804 msg
.msg_controllen
= sizeof(input_cmsg_buf_
);
805 ssize_t bytes_received
= HANDLE_EINTR(recvmsg(fd_pipe_
, &msg
, MSG_DONTWAIT
));
807 if (bytes_received
!= 1)
808 return true; // No message waiting.
810 if (!ExtractFileDescriptorsFromMsghdr(&msg
))
816 // On Posix, we need to fix up the file descriptors before the input message
819 // This will read from the input_fds_ (READWRITE mode only) and read more
820 // handles from the FD pipe if necessary.
821 bool Channel::ChannelImpl::WillDispatchInputMessage(Message
* msg
) {
822 uint16 header_fds
= msg
->header()->num_fds
;
824 return true; // Nothing to do.
826 // The message has file descriptors.
827 const char* error
= NULL
;
828 if (header_fds
> input_fds_
.size()) {
829 // The message has been completely received, but we didn't get
830 // enough file descriptors.
831 #if defined(IPC_USES_READWRITE)
832 if (!ReadFileDescriptorsFromFDPipe())
834 if (header_fds
> input_fds_
.size())
835 #endif // IPC_USES_READWRITE
836 error
= "Message needs unreceived descriptors";
839 if (header_fds
> FileDescriptorSet::kMaxDescriptorsPerMessage
)
840 error
= "Message requires an excessive number of descriptors";
843 LOG(WARNING
) << error
844 << " channel:" << this
845 << " message-type:" << msg
->type()
846 << " header()->num_fds:" << header_fds
;
847 #if defined(CHROMIUM_SELINUX)
848 LOG(WARNING
) << "In the case of SELinux this can be caused when "
849 "using a --user-data-dir to which the default "
850 "policy doesn't give the renderer access to. ";
851 #endif // CHROMIUM_SELINUX
852 // Abort the connection.
857 // The shenaniganery below with &foo.front() requires input_fds_ to have
858 // contiguous underlying storage (such as a simple array or a std::vector).
859 // This is why the header warns not to make input_fds_ a deque<>.
860 msg
->file_descriptor_set()->SetDescriptors(&input_fds_
.front(),
862 input_fds_
.erase(input_fds_
.begin(), input_fds_
.begin() + header_fds
);
866 bool Channel::ChannelImpl::DidEmptyInputBuffers() {
867 // When the input data buffer is empty, the fds should be too. If this is
868 // not the case, we probably have a rogue renderer which is trying to fill
869 // our descriptor table.
870 return input_fds_
.empty();
873 bool Channel::ChannelImpl::ExtractFileDescriptorsFromMsghdr(msghdr
* msg
) {
874 // Check that there are any control messages. On OSX, CMSG_FIRSTHDR will
875 // return an invalid non-NULL pointer in the case that controllen == 0.
876 if (msg
->msg_controllen
== 0)
879 for (cmsghdr
* cmsg
= CMSG_FIRSTHDR(msg
);
881 cmsg
= CMSG_NXTHDR(msg
, cmsg
)) {
882 if (cmsg
->cmsg_level
== SOL_SOCKET
&& cmsg
->cmsg_type
== SCM_RIGHTS
) {
883 unsigned payload_len
= cmsg
->cmsg_len
- CMSG_LEN(0);
884 DCHECK_EQ(0U, payload_len
% sizeof(int));
885 const int* file_descriptors
= reinterpret_cast<int*>(CMSG_DATA(cmsg
));
886 unsigned num_file_descriptors
= payload_len
/ 4;
887 input_fds_
.insert(input_fds_
.end(),
889 file_descriptors
+ num_file_descriptors
);
891 // Check this after adding the FDs so we don't leak them.
892 if (msg
->msg_flags
& MSG_CTRUNC
) {
901 // No file descriptors found, but that's OK.
905 void Channel::ChannelImpl::ClearInputFDs() {
906 for (size_t i
= 0; i
< input_fds_
.size(); ++i
) {
907 if (HANDLE_EINTR(close(input_fds_
[i
])) < 0)
908 PLOG(ERROR
) << "close ";
913 void Channel::ChannelImpl::HandleHelloMessage(const Message
& msg
) {
914 // The Hello message contains only the process id.
915 PickleIterator
iter(msg
);
917 if (!msg
.ReadInt(&iter
, &pid
))
920 #if defined(IPC_USES_READWRITE)
921 if (mode_
& MODE_SERVER_FLAG
) {
922 // With IPC_USES_READWRITE, the Hello message from the client to the
923 // server also contains the fd_pipe_, which will be used for all
924 // subsequent file descriptor passing.
925 DCHECK_EQ(msg
.file_descriptor_set()->size(), 1U);
926 base::FileDescriptor descriptor
;
927 if (!msg
.ReadFileDescriptor(&iter
, &descriptor
)) {
930 fd_pipe_
= descriptor
.fd
;
931 CHECK(descriptor
.auto_close
);
933 #endif // IPC_USES_READWRITE
935 listener()->OnChannelConnected(pid
);
938 void Channel::ChannelImpl::Close() {
939 // Close can be called multiple time, so we need to make sure we're
942 ResetToAcceptingConnectionState();
945 unlink(pipe_name_
.c_str());
946 must_unlink_
= false;
948 if (server_listen_pipe_
!= -1) {
949 if (HANDLE_EINTR(close(server_listen_pipe_
)) < 0)
950 DPLOG(ERROR
) << "close " << server_listen_pipe_
;
951 server_listen_pipe_
= -1;
952 // Unregister libevent for the listening socket and close it.
953 server_listen_connection_watcher_
.StopWatchingFileDescriptor();
956 CloseClientFileDescriptor();
959 //------------------------------------------------------------------------------
960 // Channel's methods simply call through to ChannelImpl.
961 Channel::Channel(const IPC::ChannelHandle
& channel_handle
, Mode mode
,
963 : channel_impl_(new ChannelImpl(channel_handle
, mode
, listener
)) {
966 Channel::~Channel() {
967 delete channel_impl_
;
970 bool Channel::Connect() {
971 return channel_impl_
->Connect();
974 void Channel::Close() {
976 channel_impl_
->Close();
979 base::ProcessId
Channel::peer_pid() const {
980 return channel_impl_
->peer_pid();
983 bool Channel::Send(Message
* message
) {
984 return channel_impl_
->Send(message
);
987 int Channel::GetClientFileDescriptor() const {
988 return channel_impl_
->GetClientFileDescriptor();
991 int Channel::TakeClientFileDescriptor() {
992 return channel_impl_
->TakeClientFileDescriptor();
995 bool Channel::AcceptsConnections() const {
996 return channel_impl_
->AcceptsConnections();
999 bool Channel::HasAcceptedConnection() const {
1000 return channel_impl_
->HasAcceptedConnection();
1003 bool Channel::GetPeerEuid(uid_t
* peer_euid
) const {
1004 return channel_impl_
->GetPeerEuid(peer_euid
);
1007 void Channel::ResetToAcceptingConnectionState() {
1008 channel_impl_
->ResetToAcceptingConnectionState();
1012 bool Channel::IsNamedServerInitialized(const std::string
& channel_id
) {
1013 return ChannelImpl::IsNamedServerInitialized(channel_id
);
1017 std::string
Channel::GenerateVerifiedChannelID(const std::string
& prefix
) {
1018 // A random name is sufficient validation on posix systems, so we don't need
1019 // an additional shared secret.
1021 std::string id
= prefix
;
1025 return id
.append(GenerateUniqueRandomChannelID());
1029 #if defined(OS_LINUX)
1031 void Channel::SetGlobalPid(int pid
) {
1032 ChannelImpl::SetGlobalPid(pid
);