Fix: urcu/futex.h: users of struct timespec should include time.h
[urcu.git] / include / urcu / futex.h
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1#ifndef _URCU_FUTEX_H
2#define _URCU_FUTEX_H
3
4/*
5 * urcu-futex.h
6 *
7 * Userspace RCU - sys_futex/compat_futex header.
8 *
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9 * Copyright 2011-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 *
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11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; either
14 * version 2.1 of the License, or (at your option) any later version.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this library; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
26#include <urcu/config.h>
6d841bc2 27#include <stdint.h>
6a29bfc1 28#include <time.h>
49617de1 29
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30#ifdef __cplusplus
31extern "C" {
67ecffc0 32#endif
36bc70a8 33
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34#define FUTEX_WAIT 0
35#define FUTEX_WAKE 1
36
37/*
38 * sys_futex compatibility header.
39 * Use *only* *either of* futex_noasync OR futex_async on a given address.
40 *
41 * futex_noasync cannot be executed in signal handlers, but ensures that
42 * it will be put in a wait queue even in compatibility mode.
43 *
44 * futex_async is signal-handler safe for the wakeup. It uses polling
45 * on the wait-side in compatibility mode.
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46 *
47 * BEWARE: sys_futex() FUTEX_WAIT may return early if interrupted
48 * (returns EINTR).
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49 */
50
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51extern int compat_futex_noasync(int32_t *uaddr, int op, int32_t val,
52 const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
53extern int compat_futex_async(int32_t *uaddr, int op, int32_t val,
54 const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
55
02be5561 56#ifdef CONFIG_RCU_HAVE_FUTEX
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57
58#include <unistd.h>
59#include <errno.h>
60#include <urcu/compiler.h>
999991c6 61#include <urcu/arch.h>
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62
63static inline int futex(int32_t *uaddr, int op, int32_t val,
64 const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
65{
66 return syscall(__NR_futex, uaddr, op, val, timeout,
67 uaddr2, val3);
68}
69
70static inline int futex_noasync(int32_t *uaddr, int op, int32_t val,
71 const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
72{
73 int ret;
74
75 ret = futex(uaddr, op, val, timeout, uaddr2, val3);
76 if (caa_unlikely(ret < 0 && errno == ENOSYS)) {
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77 /*
78 * The fallback on ENOSYS is the async-safe version of
79 * the compat futex implementation, because the
80 * async-safe compat implementation allows being used
81 * concurrently with calls to futex(). Indeed, sys_futex
82 * FUTEX_WAIT, on some architectures (mips and parisc),
83 * within a given process, spuriously return ENOSYS due
84 * to signal restart bugs on some kernel versions.
85 */
86 return compat_futex_async(uaddr, op, val, timeout,
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87 uaddr2, val3);
88 }
89 return ret;
90
91}
92
93static inline int futex_async(int32_t *uaddr, int op, int32_t val,
94 const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
95{
96 int ret;
97
98 ret = futex(uaddr, op, val, timeout, uaddr2, val3);
99 if (caa_unlikely(ret < 0 && errno == ENOSYS)) {
100 return compat_futex_async(uaddr, op, val, timeout,
101 uaddr2, val3);
102 }
103 return ret;
104}
105
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106#elif defined(__CYGWIN__)
107
108/*
109 * The futex_noasync compat code uses a weak symbol to share state across
110 * different shared object which is not possible on Windows with the
111 * Portable Executable format. Use the async compat code for both cases.
112 */
113static inline int futex_noasync(int32_t *uaddr, int op, int32_t val,
114 const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
115{
116 return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
117}
118
119static inline int futex_async(int32_t *uaddr, int op, int32_t val,
120 const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
121{
122 return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
123}
124
49617de1 125#else
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126
127static inline int futex_noasync(int32_t *uaddr, int op, int32_t val,
128 const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
129{
130 return compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3);
131}
132
133static inline int futex_async(int32_t *uaddr, int op, int32_t val,
134 const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
135{
136 return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3);
137}
138
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139#endif
140
67ecffc0 141#ifdef __cplusplus
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142}
143#endif
144
49617de1 145#endif /* _URCU_FUTEX_H */
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