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#ifndef MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
6#define MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
7
8#include <stddef.h>
9#include <sys/types.h>  // For |ssize_t|.
10
11#include <deque>
12
13#include "base/memory/scoped_ptr.h"
14#include "mojo/embedder/platform_handle.h"
15#include "mojo/system/system_impl_export.h"
16
17struct iovec;  // Declared in <sys/uio.h>.
18
19namespace mojo {
20namespace embedder {
21
22// The maximum number of handles that can be sent "at once" using
23// |PlatformChannelSendmsgWithHandles()|.
24// TODO(vtl): This number is taken from ipc/file_descriptor_set_posix.h:
25// |FileDescriptorSet::kMaxDescriptorsPerMessage|. Where does it come from?
26const size_t kPlatformChannelMaxNumHandles = 7;
27
28// Use these to write to a socket created using |PlatformChannelPair| (or
29// equivalent). These are like |write()| and |writev()|, but handle |EINTR| and
30// never raise |SIGPIPE|. (Note: On Mac, the suppression of |SIGPIPE| is set up
31// by |PlatformChannelPair|.)
32MOJO_SYSTEM_IMPL_EXPORT ssize_t
33    PlatformChannelWrite(PlatformHandle h, const void* bytes, size_t num_bytes);
34MOJO_SYSTEM_IMPL_EXPORT ssize_t
35    PlatformChannelWritev(PlatformHandle h, struct iovec* iov, size_t num_iov);
36
37// Writes data, and the given set of |PlatformHandle|s (i.e., file descriptors)
38// over the Unix domain socket given by |h| (e.g., created using
39// |PlatformChannelPair()|). All the handles must be valid, and there must be at
40// least one and at most |kPlatformChannelMaxNumHandles| handles. The return
41// value is as for |sendmsg()|, namely -1 on failure and otherwise the number of
42// bytes of data sent on success (note that this may not be all the data
43// specified by |iov|). (The handles are not closed, regardless of success or
44// failure.)
45MOJO_SYSTEM_IMPL_EXPORT ssize_t
46    PlatformChannelSendmsgWithHandles(PlatformHandle h,
47                                      struct iovec* iov,
48                                      size_t num_iov,
49                                      PlatformHandle* platform_handles,
50                                      size_t num_platform_handles);
51
52// TODO(vtl): Remove this once I've switched things over to
53// |PlatformChannelSendmsgWithHandles()|.
54// Sends |PlatformHandle|s (i.e., file descriptors) over the Unix domain socket
55// (e.g., created using PlatformChannelPair|). (These will be sent in a single
56// message having one null byte of data and one control message header with all
57// the file descriptors.) All of the handles must be valid, and there must be at
58// most |kPlatformChannelMaxNumHandles| (and at least one handle). Returns true
59// on success, in which case it closes all the handles.
60MOJO_SYSTEM_IMPL_EXPORT bool PlatformChannelSendHandles(PlatformHandle h,
61                                                        PlatformHandle* handles,
62                                                        size_t num_handles);
63
64// Wrapper around |recvmsg()|, which will extract any attached file descriptors
65// (in the control message) to |PlatformHandle|s (and append them to
66// |platform_handles|). (This also handles |EINTR|.)
67MOJO_SYSTEM_IMPL_EXPORT ssize_t
68    PlatformChannelRecvmsg(PlatformHandle h,
69                           void* buf,
70                           size_t num_bytes,
71                           std::deque<PlatformHandle>* platform_handles);
72
73}  // namespace embedder
74}  // namespace mojo
75
76#endif  // MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
77