Fix: handle sys_futex() FUTEX_WAIT interrupted by signal
[urcu.git] / 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
29 #ifdef __cplusplus
30 extern "C" {
31 #endif
32
33 #define FUTEX_WAIT 0
34 #define FUTEX_WAKE 1
35
36 /*
37 * sys_futex compatibility header.
38 * Use *only* *either of* futex_noasync OR futex_async on a given address.
39 *
40 * futex_noasync cannot be executed in signal handlers, but ensures that
41 * it will be put in a wait queue even in compatibility mode.
42 *
43 * futex_async is signal-handler safe for the wakeup. It uses polling
44 * on the wait-side in compatibility mode.
45 *
46 * BEWARE: sys_futex() FUTEX_WAIT may return early if interrupted
47 * (returns EINTR).
48 */
49
50 #ifdef CONFIG_RCU_HAVE_FUTEX
51 #include <urcu/syscall-compat.h>
52 #define futex(...) syscall(__NR_futex, __VA_ARGS__)
53 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3) \
54 futex(uaddr, op, val, timeout, uaddr2, val3)
55 #define futex_async(uaddr, op, val, timeout, uaddr2, val3) \
56 futex(uaddr, op, val, timeout, uaddr2, val3)
57 #else
58 extern int compat_futex_noasync(int32_t *uaddr, int op, int32_t val,
59 const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
60 #define futex_noasync(uaddr, op, val, timeout, uaddr2, val3) \
61 compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3)
62 extern int compat_futex_async(int32_t *uaddr, int op, int32_t val,
63 const struct timespec *timeout, int32_t *uaddr2, int32_t val3);
64 #define futex_async(uaddr, op, val, timeout, uaddr2, val3) \
65 compat_futex_async(uaddr, op, val, timeout, uaddr2, val3)
66 #endif
67
68 #ifdef __cplusplus
69 }
70 #endif
71
72 #endif /* _URCU_FUTEX_H */
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