1 /*
2 * Copyright (C) 2008 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 <errno.h>
30 #include <stdio.h>
31
32 #include "local.h"
33
34 // We can't use the OpenBSD implementation which uses kernel-specific
35 // APIs not available on Linux. Instead we use a pthread_mutex_t within
36 // struct __sfileext (see fileext.h).
37
flockfile(FILE * fp)38 void flockfile(FILE* fp) {
39 if (!__sdidinit) {
40 __sinit();
41 }
42
43 if (fp != NULL) {
44 pthread_mutex_lock(&_FLOCK(fp));
45 }
46 }
47
ftrylockfile(FILE * fp)48 int ftrylockfile(FILE* fp) {
49 if (!__sdidinit) {
50 __sinit();
51 }
52
53 // The specification for ftrylockfile() says it returns 0 on success,
54 // or non-zero on error. So return an errno code directly on error.
55 if (fp == NULL) {
56 return EINVAL;
57 }
58
59 return pthread_mutex_trylock(&_FLOCK(fp));
60 }
61
funlockfile(FILE * fp)62 void funlockfile(FILE* fp) {
63 if (!__sdidinit) {
64 __sinit();
65 }
66
67 if (fp != NULL) {
68 pthread_mutex_unlock(&_FLOCK(fp));
69 }
70 }
71