/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005, David Xu <davidxu@freebsd.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "namespace.h"
#include <errno.h>
#include <pthread.h>
#include "un-namespace.h"

#include "thr_private.h"

int     _pthread_peekjoin_np(pthread_t pthread, void **thread_return);
int     _pthread_tryjoin_np(pthread_t pthread, void **thread_return);
int     _pthread_timedjoin_np(pthread_t pthread, void **thread_return,
            const struct timespec *abstime);
static int join_common(pthread_t, void **, const struct timespec *, bool peek,
            bool try);

__weak_reference(_thr_join, pthread_join);
__weak_reference(_thr_join, _pthread_join);
__weak_reference(_pthread_timedjoin_np, pthread_timedjoin_np);
__weak_reference(_pthread_peekjoin_np, pthread_peekjoin_np);
__weak_reference(_pthread_tryjoin_np, pthread_tryjoin_np);

static void
backout_join(struct pthread *pthread, struct pthread *curthread)
{
        THR_THREAD_LOCK(curthread, pthread);
        pthread->joiner = NULL;
        THR_THREAD_UNLOCK(curthread, pthread);
}

static void
backout_join_pop(void *arg)
{
        struct pthread *pthread = (struct pthread *)arg;
        struct pthread *curthread = _get_curthread();

        backout_join(pthread, curthread);
}

int
_thr_join(pthread_t pthread, void **thread_return)
{
        return (join_common(pthread, thread_return, NULL, false, false));
}

int
_pthread_timedjoin_np(pthread_t pthread, void **thread_return,
        const struct timespec *abstime)
{
        if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
            abstime->tv_nsec >= 1000000000)
                return (EINVAL);

        return (join_common(pthread, thread_return, abstime, false, false));
}

int
_pthread_peekjoin_np(pthread_t pthread, void **thread_return)
{
        return (join_common(pthread, thread_return, NULL, true, false));
}

int
_pthread_tryjoin_np(pthread_t pthread, void **thread_return)
{
        return (join_common(pthread, thread_return, NULL, false, true));
}

static void
join_common_joined(struct pthread *pthread, struct pthread *curthread,
    void **thread_return)
{
        void *tmp;

        tmp = pthread->ret;
        pthread->flags |= THR_FLAGS_DETACHED;
        pthread->joiner = NULL;
        _thr_try_gc(curthread, pthread); /* thread lock released */

        if (thread_return != NULL)
                *thread_return = tmp;
}

/*
 * Cancellation behavior:
 *   if the thread is canceled, joinee is not recycled.
 */
static int
join_common(pthread_t pthread, void **thread_return,
    const struct timespec *abstime, bool peek, bool try)
{
        struct pthread *curthread = _get_curthread();
        struct timespec ts, ts2, *tsp;
        long tid;
        int ret;

        if (pthread == NULL)
                return (EINVAL);

        if (pthread == curthread)
                return (EDEADLK);

        if ((ret = _thr_find_thread(curthread, pthread, 1)) != 0)
                return (ESRCH);

        if ((pthread->flags & THR_FLAGS_DETACHED) != 0) {
                ret = EINVAL;
        } else if (pthread->joiner != NULL) {
                /* Multiple joiners are not supported. */
                ret = ENOTSUP;
        }
        if (ret != 0) {
                THR_THREAD_UNLOCK(curthread, pthread);
                return (ret);
        }

        /* Only peek into status, do not gc the thread. */
        if (peek) {
                if (pthread->tid != TID_TERMINATED)
                        ret = EBUSY;
                else if (thread_return != NULL)
                        *thread_return = pthread->ret;
                THR_THREAD_UNLOCK(curthread, pthread);
                return (ret);
        }

        /* Only try to join. */
        if (try) {
                if (pthread->tid != TID_TERMINATED) {
                        THR_THREAD_UNLOCK(curthread, pthread);
                        return (EBUSY);
                }
                join_common_joined(pthread, curthread, thread_return);
                return (0);
        }

        /* Set the running thread to be the joiner: */
        pthread->joiner = curthread;

        THR_THREAD_UNLOCK(curthread, pthread);

        THR_CLEANUP_PUSH(curthread, backout_join_pop, pthread);
        _thr_cancel_enter(curthread);

        tid = pthread->tid;
        while (pthread->tid != TID_TERMINATED) {
                _thr_testcancel(curthread);
                if (abstime != NULL) {
                        clock_gettime(CLOCK_REALTIME, &ts);
                        TIMESPEC_SUB(&ts2, abstime, &ts);
                        if (ts2.tv_sec < 0) {
                                ret = ETIMEDOUT;
                                break;
                        }
                        tsp = &ts2;
                } else
                        tsp = NULL;
                ret = _thr_umtx_wait(&pthread->tid, tid, tsp);
                if (ret == ETIMEDOUT)
                        break;
        }

        _thr_cancel_leave(curthread, 0);
        THR_CLEANUP_POP(curthread, 0);

        if (ret == ETIMEDOUT || ret == EBUSY) {
                backout_join(pthread, curthread);
        } else {
                ret = 0;
                THR_THREAD_LOCK(curthread, pthread);
                join_common_joined(pthread, curthread, thread_return);
        }
        return (ret);
}