Mojo: POSIX: Add a PlatformChannelSendmsgWithHandles().

mojo/embedder/platform_channel_utils_posix.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/embedder/platform_channel_utils_posix.h"
 
 #include <sys/socket.h>
 #include <sys/uio.h>
 #include <unistd.h>
 
@@ skipping 29 matching lines @@
 // Flags to use with calling |send()| or |sendmsg()| (see above).
 #if defined(OS_MACOSX)
 const int kSendFlags = 0;
 #else
 const int kSendFlags = MSG_NOSIGNAL;
 #endif
 
 ssize_t PlatformChannelWrite(PlatformHandle h,
                              const void* bytes,
                              size_t num_bytes) {
+  DCHECK(h.is_valid());
+  DCHECK(bytes);
+  DCHECK_GT(num_bytes, 0u);
+
 #if defined(OS_MACOSX)
   return HANDLE_EINTR(write(h.fd, bytes, num_bytes));
 #else
   return send(h.fd, bytes, num_bytes, kSendFlags);
 #endif
 }
 
 ssize_t PlatformChannelWritev(PlatformHandle h,
                               struct iovec* iov,
                               size_t num_iov) {
+  DCHECK(h.is_valid());
+  DCHECK(iov);
+  DCHECK_GT(num_iov, 0u);
+
 #if defined(OS_MACOSX)
   return HANDLE_EINTR(writev(h.fd, iov, static_cast<int>(num_iov)));
 #else
   struct msghdr msg = {};
   msg.msg_iov = iov;
   msg.msg_iovlen = num_iov;
   return HANDLE_EINTR(sendmsg(h.fd, &msg, kSendFlags));
 #endif
 }
 
+ssize_t PlatformChannelSendmsgWithHandles(PlatformHandle h,
+                                          struct iovec* iov,
+                                          size_t num_iov,
+                                          PlatformHandle* platform_handles,
+                                          size_t num_platform_handles) {
+  DCHECK(iov);
+  DCHECK_GT(num_iov, 0u);
+  DCHECK(platform_handles);
+  DCHECK_GT(num_platform_handles, 0u);

[yzshen1, 2014/05/21 23:50:02]

nit: It might be good to also DCHECK that it is not greater than
kPlatformChannelMaxNumHandles.

[viettrungluu, 2014/05/22 00:21:44]

Done.

+
+  char cmsg_buf[CMSG_SPACE(kPlatformChannelMaxNumHandles * sizeof(int))];
+  struct msghdr msg = {};
+  msg.msg_iov = iov;
+  msg.msg_iovlen = num_iov;
+  msg.msg_control = cmsg_buf;
+  msg.msg_controllen = CMSG_LEN(num_platform_handles * sizeof(int));
+  struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg);
+  cmsg->cmsg_level = SOL_SOCKET;
+  cmsg->cmsg_type = SCM_RIGHTS;
+  cmsg->cmsg_len = CMSG_LEN(num_platform_handles * sizeof(int));
+  for (size_t i = 0; i < num_platform_handles; i++) {
+    DCHECK(platform_handles[i].is_valid());
+    reinterpret_cast<int*>(CMSG_DATA(cmsg))[i] = platform_handles[i].fd;
+  }
+
+  return HANDLE_EINTR(sendmsg(h.fd, &msg, kSendFlags));
+}
+
 bool PlatformChannelSendHandles(PlatformHandle h,
                                 PlatformHandle* handles,
                                 size_t num_handles) {
   DCHECK(handles);
   DCHECK_GT(num_handles, 0u);
   DCHECK_LE(num_handles, kPlatformChannelMaxNumHandles);
 
   // Note: |sendmsg()| fails on Mac if we don't write at least one character.
   struct iovec iov = { const_cast<char*>(""), 1 };
   char cmsg_buf[CMSG_SPACE(kPlatformChannelMaxNumHandles * sizeof(int))];
@@ skipping 61 matching lines @@
         DCHECK(platform_handles->back().is_valid());
       }
     }
   }
 
   return result;
 }
 
 }  // namespace embedder
 }  // namespace mojo