1/*
2 * Copyright 2016-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <folly/portability/SysFile.h>
18
19#ifdef _WIN32
20#include <limits>
21
22#include <folly/portability/Windows.h>
23
24extern "C" int flock(int fd, int operation) {
25 HANDLE h = (HANDLE)_get_osfhandle(fd);
26 if (h == INVALID_HANDLE_VALUE) {
27 return -1;
28 }
29
30 constexpr DWORD kMaxDWORD = std::numeric_limits<DWORD>::max();
31 if (operation & LOCK_UN) {
32 if (!UnlockFile(h, 0, 0, kMaxDWORD, kMaxDWORD)) {
33 return -1;
34 }
35 } else {
36 DWORD flags = DWORD(
37 (operation & LOCK_NB ? LOCKFILE_FAIL_IMMEDIATELY : 0) |
38 (operation & LOCK_EX ? LOCKFILE_EXCLUSIVE_LOCK : 0));
39 OVERLAPPED ov = {};
40 if (!LockFileEx(h, flags, 0, kMaxDWORD, kMaxDWORD, &ov)) {
41 return -1;
42 }
43 }
44 return 0;
45}
46#endif
47