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/***
This file is part of PulseAudio.
Copyright 2006 Lennart Poettering
Copyright 2013 Albert Zeyer
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of the License,
or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <errno.h>
#include <pthread.h>
#include <semaphore.h>
#include <sys/types.h>
#include <unistd.h>
#include <pulse/xmalloc.h>
#include <pulsecore/macro.h>
#include <pulsecore/atomic.h>
#include <pulsecore/core-util.h>
#include "semaphore.h"
/* OSX doesn't support unnamed semaphores (via sem_init).
* Thus, we use a counter to give them enumerated names. */
static pa_atomic_t id_counter = PA_ATOMIC_INIT(0);
struct pa_semaphore {
sem_t *sem;
int id;
};
static char *sem_name(char *fn, size_t l, int id) {
pa_snprintf(fn, l, "/pulse-sem-%u-%u", getpid(), id);
return fn;
}
pa_semaphore *pa_semaphore_new(unsigned value) {
pa_semaphore *s;
char fn[32];
s = pa_xnew(pa_semaphore, 1);
s->id = pa_atomic_inc(&id_counter);
sem_name(fn, sizeof(fn), s->id);
sem_unlink(fn); /* in case an old stale semaphore is left around */
pa_assert_se(s->sem = sem_open(fn, O_CREAT|O_EXCL, 0700, value));
pa_assert(s->sem != SEM_FAILED);
return s;
}
void pa_semaphore_free(pa_semaphore *s) {
char fn[32];
pa_assert(s);
pa_assert_se(sem_close(s->sem) == 0);
sem_name(fn, sizeof(fn), s->id);
pa_assert_se(sem_unlink(fn) == 0);
pa_xfree(s);
}
void pa_semaphore_post(pa_semaphore *s) {
pa_assert(s);
pa_assert_se(sem_post(s->sem) == 0);
}
void pa_semaphore_wait(pa_semaphore *s) {
int ret;
pa_assert(s);
do {
ret = sem_wait(s->sem);
} while (ret < 0 && errno == EINTR);
pa_assert(ret == 0);
}
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