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
41 struct timespec;
42
__futex(volatile void * ftx,int op,int value,const struct timespec * timeout,int bitset)43 static inline __always_inline int __futex(volatile void* ftx, int op, int value,
44 const struct timespec* timeout,
45 int bitset) {
46 // Our generated syscall assembler sets errno, but our callers (pthread functions) don't want to.
47 int saved_errno = errno;
48 int result = syscall(__NR_futex, ftx, op, value, timeout, NULL, bitset);
49 if (__predict_false(result == -1)) {
50 result = -errno;
51 errno = saved_errno;
52 }
53 return result;
54 }
55
__futex_wake(volatile void * ftx,int count)56 static inline int __futex_wake(volatile void* ftx, int count) {
57 return __futex(ftx, FUTEX_WAKE, count, NULL, 0);
58 }
59
__futex_wake_ex(volatile void * ftx,bool shared,int count)60 static inline int __futex_wake_ex(volatile void* ftx, bool shared, int count) {
61 return __futex(ftx, shared ? FUTEX_WAKE : FUTEX_WAKE_PRIVATE, count, NULL, 0);
62 }
63
__futex_wait(volatile void * ftx,int value,const struct timespec * timeout)64 static inline int __futex_wait(volatile void* ftx, int value, const struct timespec* timeout) {
65 return __futex(ftx, FUTEX_WAIT, value, timeout, 0);
66 }
67
__futex_wait_ex(volatile void * ftx,bool shared,int value,bool use_realtime_clock,const struct timespec * abs_timeout)68 static inline int __futex_wait_ex(volatile void* ftx, bool shared, int value,
69 bool use_realtime_clock, const struct timespec* abs_timeout) {
70 return __futex(ftx, (shared ? FUTEX_WAIT_BITSET : FUTEX_WAIT_BITSET_PRIVATE) |
71 (use_realtime_clock ? FUTEX_CLOCK_REALTIME : 0), value, abs_timeout,
72 FUTEX_BITSET_MATCH_ANY);
73 }
74
75 __END_DECLS
76
77 #endif /* _BIONIC_FUTEX_H */
78