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#ifndef _BIONIC_FUTEX_H
29#define _BIONIC_FUTEX_H
30
31#include <errno.h>
32#include <linux/futex.h>
33#include <stdbool.h>
34#include <stddef.h>
35#include <sys/cdefs.h>
36#include <sys/syscall.h>
37#include <unistd.h>
38
39__BEGIN_DECLS
40
41struct timespec;
42
43static inline __always_inline int __futex(volatile void* ftx, int op, int value, const struct timespec* timeout) {
44  // Our generated syscall assembler sets errno, but our callers (pthread functions) don't want to.
45  int saved_errno = errno;
46  int result = syscall(__NR_futex, ftx, op, value, timeout);
47  if (__predict_false(result == -1)) {
48    result = -errno;
49    errno = saved_errno;
50  }
51  return result;
52}
53
54static inline int __futex_wake(volatile void* ftx, int count) {
55  return __futex(ftx, FUTEX_WAKE, count, NULL);
56}
57
58static inline int __futex_wake_ex(volatile void* ftx, bool shared, int count) {
59  return __futex(ftx, shared ? FUTEX_WAKE : FUTEX_WAKE_PRIVATE, count, NULL);
60}
61
62static inline int __futex_wait(volatile void* ftx, int value, const struct timespec* timeout) {
63  return __futex(ftx, FUTEX_WAIT, value, timeout);
64}
65
66static inline int __futex_wait_ex(volatile void* ftx, bool shared, int value, const struct timespec* timeout) {
67  return __futex(ftx, shared ? FUTEX_WAIT : FUTEX_WAIT_PRIVATE, value, timeout);
68}
69
70__END_DECLS
71
72#endif /* _BIONIC_FUTEX_H */
73