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1/* $OpenBSD: synch.h,v 1.10 2024/01/07 19:44:28 cheloha Exp $ */
2/*
3 * Copyright (c) 2017 Martin Pieuchot
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <sys/atomic.h>
19#include <sys/time.h>
20#include <sys/futex.h>
21
22static inline int
23_wake(volatile uint32_t *p, int n)
24{
25 return futex(p, FUTEX_WAKE, n, NULL, NULL);
26}
27
28static inline int
29_twait(volatile uint32_t *p, int val, clockid_t clockid, const struct timespec *abs)
30{
31 struct timespec now, rel;
32 int saved_errno = errno;
33 int error;
34
35 if (abs == NULL) {
36 error = futex(p, FUTEX_WAIT, val, NULL, NULL);
37 if (error == -1) {
38 error = errno;
39 errno = saved_errno;
40 }
41 return error;
42 }
43
44 if (!timespecisvalid(abs) || clock_gettime(clockid, &now))
45 return EINVAL;
46
47 if (timespeccmp(abs, &now, <=))
48 return ETIMEDOUT;
49 timespecsub(abs, &now, &rel);
50
51 error = futex(p, FUTEX_WAIT, val, &rel, NULL);
52 if (error == -1) {
53 error = errno;
54 errno = saved_errno;
55 }
56 return error;
57}
58
59static inline int
60_requeue(volatile uint32_t *p, int n, int m, volatile uint32_t *q)
61{
62 return futex(p, FUTEX_REQUEUE, n, (void *)(long)m, q);
63}