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/* $OpenBSD: rthread_barrier.c,v 1.1 2012/04/11 10:18:46 pirofti Exp $ */
/*
* Copyright (c) 2012 Paul Irofti <pirofti@openbsd.org>
*
* Permission to use, copy, modify, and/or 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 <errno.h>
#include <stdlib.h>
#include <pthread.h>
#include "rthread.h"
int
pthread_barrier_init(pthread_barrier_t *barrier, pthread_barrierattr_t *attr,
unsigned int count) {
int rc = 0;
pthread_barrier_t b = NULL;
if (barrier == NULL) {
return EINVAL;
}
if (attr != NULL) {
if (*attr == NULL) {
return EINVAL;
}
if ((*attr)->pshared != PTHREAD_PROCESS_PRIVATE) {
return ENOTSUP;
}
}
b = calloc(1, sizeof *b);
if (b == NULL) {
return ENOMEM;
}
if ((rc = pthread_mutex_init(&b->mutex, NULL))) {
goto err;
}
if ((rc = pthread_cond_init(&b->cond, NULL))) {
goto err;
}
b->threshold = count;
*barrier = b;
return 0;
err:
if (b) {
if (b->mutex) {
pthread_mutex_destroy(&b->mutex);
}
if (b->cond) {
pthread_cond_destroy(&b->cond);
}
free(b);
}
return rc;
}
int
pthread_barrier_destroy(pthread_barrier_t *barrier)
{
pthread_barrier_t b;
if (barrier == NULL || *barrier == NULL) {
return EINVAL;
}
b = *barrier;
if (b->sofar > 0) {
return EBUSY;
}
*barrier = NULL;
pthread_mutex_destroy(&b->mutex);
pthread_cond_destroy(&b->cond);
free(b);
return 0;
}
int
pthread_barrier_wait(pthread_barrier_t *barrier)
{
pthread_barrier_t b;
int rc, old_state, gen;
int done = 0;
if (barrier == NULL || *barrier == NULL) {
return EINVAL;
}
if ((rc = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &old_state))) {
return rc;
}
b = *barrier;
if ((rc = pthread_mutex_lock(&b->mutex))) {
goto cancel;
}
_rthread_debug(6, "sofar: %d, threshold: %d\n", b->sofar, b->threshold);
if (++b->sofar == b->threshold) {
b->sofar = 0;
b->generation++;
if ((rc = pthread_cond_broadcast(&b->cond))) {
goto err;
}
done = 1;
_rthread_debug(6, "threshold reached\n");
} else {
gen = b->generation;
_rthread_debug(6, "waiting on condition\n");
do {
if ((rc = pthread_cond_wait(&b->cond, &b->mutex))) {
goto err;
}
} while (gen == b->generation);
}
err:
if ((rc = pthread_mutex_unlock(&b->mutex))) {
return rc;
}
cancel:
rc = pthread_setcancelstate(old_state, NULL);
if (rc == 0 && done) {
rc = PTHREAD_BARRIER_SERIAL_THREAD;
}
return rc;
}
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