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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2025 J. Cardenas Marquez <acm@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, 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 "pthreads_portable.h"
int portable_rwlock_init(portable_rwlock_t *rw) {
if (pthread_mutex_init(&rw->lock, NULL) != 0) return -1;
if (pthread_cond_init(&rw->readers_ok, NULL) != 0) return -1;
if (pthread_cond_init(&rw->writers_ok, NULL) != 0) return -1;
rw->active_readers = 0;
rw->waiting_writers = 0;
rw->writer_active = 0;
return 0;
}
int portable_rwlock_rdlock(portable_rwlock_t *rw) {
if (pthread_mutex_lock(&rw->lock) != 0) return -1;
while (rw->writer_active || rw->waiting_writers > 0) {
if (pthread_cond_wait(&rw->readers_ok, &rw->lock) != 0) {
pthread_mutex_unlock(&rw->lock);
return -1;
}
}
rw->active_readers++;
return pthread_mutex_unlock(&rw->lock);
}
int portable_rwlock_rdunlock(portable_rwlock_t *rw) {
if (pthread_mutex_lock(&rw->lock) != 0) return -1;
rw->active_readers--;
if (rw->active_readers == 0 && rw->waiting_writers > 0)
pthread_cond_signal(&rw->writers_ok);
return pthread_mutex_unlock(&rw->lock);
}
int portable_rwlock_wrlock(portable_rwlock_t *rw) {
if (pthread_mutex_lock(&rw->lock) != 0) return -1;
rw->waiting_writers++;
while (rw->writer_active || rw->active_readers > 0) {
if (pthread_cond_wait(&rw->writers_ok, &rw->lock) != 0) {
rw->waiting_writers--;
pthread_mutex_unlock(&rw->lock);
return -1;
}
}
rw->waiting_writers--;
rw->writer_active = 1;
return pthread_mutex_unlock(&rw->lock);
}
int portable_rwlock_wrunlock(portable_rwlock_t *rw) {
if (pthread_mutex_lock(&rw->lock) != 0) return -1;
rw->writer_active = 0;
if (rw->waiting_writers > 0)
pthread_cond_signal(&rw->writers_ok);
else
pthread_cond_broadcast(&rw->readers_ok);
return pthread_mutex_unlock(&rw->lock);
}
int portable_rwlock_destroy(portable_rwlock_t *rw) {
if (pthread_mutex_destroy(&rw->lock) != 0) return -1;
if (pthread_cond_destroy(&rw->readers_ok) != 0) return -1;
if (pthread_cond_destroy(&rw->writers_ok) != 0) return -1;
return 0;
}
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