ipc/ipc_platform_file.cc

   1 // Copyright (c) 2011 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 #include "ipc/ipc_platform_file.h"
   6
   7 namespace IPC {
   8
   9 PlatformFileForTransit GetFileHandleForProcess(base::PlatformFile handle,
  10                                                base::ProcessHandle process,
  11                                                bool close_source_handle) {
  12   IPC::PlatformFileForTransit out_handle;
  13 #if defined(OS_WIN)
  14   DWORD options = DUPLICATE_SAME_ACCESS;
  15   if (close_source_handle)
  16     options |= DUPLICATE_CLOSE_SOURCE;
  17   if (!::DuplicateHandle(::GetCurrentProcess(),
  18                          handle,
  19                          process,
  20                          &out_handle,
  21                          0,
  22                          FALSE,
  23                          options)) {
  24     out_handle = IPC::InvalidPlatformFileForTransit();
  25   }
  26 #elif defined(OS_POSIX)
  27   // If asked to close the source, we can simply re-use the source fd instead of
  28   // dup()ing and close()ing.
  29   // When we're not closing the source, we need to duplicate the handle and take
  30   // ownership of that. The reason is that this function is often used to
  31   // generate IPC messages, and the handle must remain valid until it's sent to
  32   // the other process from the I/O thread. Without the dup, calling code might
  33   // close the source handle before the message is sent, creating a race
  34   // condition.
  35   int fd = close_source_handle ? handle : ::dup(handle);
  36   out_handle = base::FileDescriptor(fd, true);
  37 #else
  38   #error Not implemented.
  39 #endif
  40   return out_handle;
  41 }
  42
  43 }  // namespace IPC