mojo/embedder/platform_channel_utils_posix.h

   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
  17 struct iovec;  // Declared in <sys/uio.h>.
  18
  19 namespace mojo {
  20 namespace 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?
  26 const 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|.)
  32 MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelWrite(PlatformHandle h,
  33                                                      const void* bytes,
  34                                                      size_t num_bytes);
  35 MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelWritev(PlatformHandle h,
  36                                                       struct iovec* iov,
  37                                                       size_t num_iov);
  38
  39 // Writes data, and the given set of |PlatformHandle|s (i.e., file descriptors)
  40 // over the Unix domain socket given by |h| (e.g., created using
  41 // |PlatformChannelPair()|). All the handles must be valid, and there must be at
  42 // least one and at most |kPlatformChannelMaxNumHandles| handles. The return
  43 // value is as for |sendmsg()|, namely -1 on failure and otherwise the number of
  44 // bytes of data sent on success (note that this may not be all the data
  45 // specified by |iov|). (The handles are not closed, regardless of success or
  46 // failure.)
  47 MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelSendmsgWithHandles(
  48     PlatformHandle h,
  49     struct iovec* iov,
  50     size_t num_iov,
  51     PlatformHandle* platform_handles,
  52     size_t num_platform_handles);
  53
  54 // TODO(vtl): Remove this once I've switched things over to
  55 // |PlatformChannelSendmsgWithHandles()|.
  56 // Sends |PlatformHandle|s (i.e., file descriptors) over the Unix domain socket
  57 // (e.g., created using PlatformChannelPair|). (These will be sent in a single
  58 // message having one null byte of data and one control message header with all
  59 // the file descriptors.) All of the handles must be valid, and there must be at
  60 // most |kPlatformChannelMaxNumHandles| (and at least one handle). Returns true
  61 // on success, in which case it closes all the handles.
  62 MOJO_SYSTEM_IMPL_EXPORT bool PlatformChannelSendHandles(PlatformHandle h,
  63                                                         PlatformHandle* handles,
  64                                                         size_t num_handles);
  65
  66 // Wrapper around |recvmsg()|, which will extract any attached file descriptors
  67 // (in the control message) to |PlatformHandle|s (and append them to
  68 // |platform_handles|). (This also handles |EINTR|.)
  69 MOJO_SYSTEM_IMPL_EXPORT ssize_t PlatformChannelRecvmsg(
  70     PlatformHandle h,
  71     void* buf,
  72     size_t num_bytes,
  73     std::deque<PlatformHandle>* platform_handles);
  74
  75 }  // namespace embedder
  76 }  // namespace mojo
  77
  78 #endif  // MOJO_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_