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.
4
5 #include "ipc/ipc_platform_file.h"
6
7 #if defined(OS_POSIX)
8 #include <unistd.h>
9 #endif
10
11 namespace IPC {
12
GetFileHandleForProcess(base::PlatformFile handle,base::ProcessHandle process,bool close_source_handle)13 PlatformFileForTransit GetFileHandleForProcess(base::PlatformFile handle,
14 base::ProcessHandle process,
15 bool close_source_handle) {
16 IPC::PlatformFileForTransit out_handle;
17 #if defined(OS_WIN)
18 DWORD options = DUPLICATE_SAME_ACCESS;
19 if (close_source_handle)
20 options |= DUPLICATE_CLOSE_SOURCE;
21 if (handle == INVALID_HANDLE_VALUE ||
22 !::DuplicateHandle(::GetCurrentProcess(),
23 handle,
24 process,
25 &out_handle,
26 0,
27 FALSE,
28 options)) {
29 out_handle = IPC::InvalidPlatformFileForTransit();
30 }
31 #elif defined(OS_POSIX)
32 // If asked to close the source, we can simply re-use the source fd instead of
33 // dup()ing and close()ing.
34 // When we're not closing the source, we need to duplicate the handle and take
35 // ownership of that. The reason is that this function is often used to
36 // generate IPC messages, and the handle must remain valid until it's sent to
37 // the other process from the I/O thread. Without the dup, calling code might
38 // close the source handle before the message is sent, creating a race
39 // condition.
40 int fd = close_source_handle ? handle : ::dup(handle);
41 out_handle = base::FileDescriptor(fd, true);
42 #else
43 #error Not implemented.
44 #endif
45 return out_handle;
46 }
47
TakeFileHandleForProcess(base::File file,base::ProcessHandle process)48 PlatformFileForTransit TakeFileHandleForProcess(base::File file,
49 base::ProcessHandle process) {
50 return GetFileHandleForProcess(file.TakePlatformFile(), process, true);
51 }
52
53 } // namespace IPC
54