Fix: urcu/futex.h: users of struct timespec should include time.h
[urcu.git] / include / urcu / futex.h
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 *
9 * Copyright 2011-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 *
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>
27 #include <stdint.h>
28 #include <time.h>
29
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33
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.
46 *
47 * BEWARE: sys_futex() FUTEX_WAIT may return early if interrupted
48 * (returns EINTR).
49 */
50
51 extern int compat_futex_noasync(int32_t *uaddr, int op, int32_t val,
52 const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
53 extern int compat_futex_async(int32_t *uaddr, int op, int32_t val,
54 const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
55
56 #ifdef CONFIG_RCU_HAVE_FUTEX
57
58 #include <unistd.h>
59 #include <errno.h>
60 #include <urcu/compiler.h>
61 #include <urcu/arch.h>
62
63 static 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
70 static 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)) {
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,
87 uaddr2, val3);
88 }
89 return ret;
90
91 }
92
93 static 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
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 */
113 static 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
119 static 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
125 #else
126
127 static 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
133 static 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
139 #endif
140
141 #ifdef __cplusplus
142 }
143 #endif
144
145 #endif /* _URCU_FUTEX_H */
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