1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <unistd.h>
30
31#include <errno.h>
32#include <fcntl.h>
33#include <string.h>
34
35int lockf64(int fd, int cmd, off64_t length) {
36  // Translate POSIX lockf into fcntl.
37  struct flock64 fl;
38  memset(&fl, 0, sizeof(fl));
39  fl.l_whence = SEEK_CUR;
40  fl.l_start = 0;
41  fl.l_len = length;
42
43  if (cmd == F_ULOCK) {
44    fl.l_type = F_UNLCK;
45    cmd = F_SETLK64;
46    return fcntl(fd, F_SETLK64, &fl);
47  }
48
49  if (cmd == F_LOCK) {
50    fl.l_type = F_WRLCK;
51    return fcntl(fd, F_SETLKW64, &fl);
52  }
53
54  if (cmd == F_TLOCK) {
55    fl.l_type = F_WRLCK;
56    return fcntl(fd, F_SETLK64, &fl);
57  }
58
59  if (cmd == F_TEST) {
60    fl.l_type = F_RDLCK;
61    if (fcntl(fd, F_GETLK64, &fl) == -1) return -1;
62    if (fl.l_type == F_UNLCK || fl.l_pid == getpid()) return 0;
63    errno = EACCES;
64    return -1;
65  }
66
67  errno = EINVAL;
68  return -1;
69}
70
71int lockf(int fd, int cmd, off_t length) {
72  return lockf64(fd, cmd, length);
73}
74