/*      $OpenBSD: synch.h,v 1.10 2024/01/07 19:44:28 cheloha Exp $ */
/*
 * Copyright (c) 2017 Martin Pieuchot
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/atomic.h>
#include <sys/time.h>
#include <sys/futex.h>

static inline int
_wake(volatile uint32_t *p, int n)
{
        return futex(p, FUTEX_WAKE, n, NULL, NULL);
}

static inline int
_twait(volatile uint32_t *p, int val, clockid_t clockid, const struct timespec *abs)
{
        struct timespec now, rel;
        int saved_errno = errno;
        int error;

        if (abs == NULL) {
                error = futex(p, FUTEX_WAIT, val, NULL, NULL);
                if (error == -1) {
                        error = errno;
                        errno = saved_errno;
                }
                return error;
        }

        if (!timespecisvalid(abs) || clock_gettime(clockid, &now))
                return EINVAL;

        if (timespeccmp(abs, &now, <=))
                return ETIMEDOUT;
        timespecsub(abs, &now, &rel);

        error = futex(p, FUTEX_WAIT, val, &rel, NULL);
        if (error == -1) {
                error = errno;
                errno = saved_errno;
        }
        return error;
}

static inline int
_requeue(volatile uint32_t *p, int n, int m, volatile uint32_t *q)
{
        return futex(p, FUTEX_REQUEUE, n, (void *)(long)m, q);
}