code.delx.au - pulseaudio/blob - src/pulsecore/semaphore-osx.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2006 Lennart Poettering
   5   Copyright 2013 Albert Zeyer
   6
   7   PulseAudio is free software; you can redistribute it and/or modify
   8   it under the terms of the GNU Lesser General Public License as published
   9   by the Free Software Foundation; either version 2.1 of the License,
  10   or (at your option) any later version.
  11
  12   PulseAudio is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with PulseAudio; if not, write to the Free Software
  19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  20   USA.
  21 ***/
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include <stdio.h>
  28 #include <errno.h>
  29 #include <pthread.h>
  30 #include <semaphore.h>
  31 #include <sys/types.h>
  32 #include <unistd.h>
  33
  34 #include <pulse/xmalloc.h>
  35 #include <pulsecore/macro.h>
  36 #include <pulsecore/atomic.h>
  37 #include <pulsecore/core-util.h>
  38
  39 #include "semaphore.h"
  40
  41 /* OSX doesn't support unnamed semaphores (via sem_init).
  42  * Thus, we use a counter to give them enumerated names. */
  43 static pa_atomic_t id_counter = PA_ATOMIC_INIT(0);
  44
  45 struct pa_semaphore {
  46     sem_t *sem;
  47     int id;
  48 };
  49
  50 static char *sem_name(char *fn, size_t l, int id) {
  51     pa_snprintf(fn, l, "/pulse-sem-%u-%u", getpid(), id);
  52     return fn;
  53 }
  54
  55 pa_semaphore *pa_semaphore_new(unsigned value) {
  56     pa_semaphore *s;
  57     char fn[32];
  58
  59     s = pa_xnew(pa_semaphore, 1);
  60     s->id = pa_atomic_inc(&id_counter);
  61     sem_name(fn, sizeof(fn), s->id);
  62     sem_unlink(fn); /* in case an old stale semaphore is left around */
  63     pa_assert_se(s->sem = sem_open(fn, O_CREAT|O_EXCL, 0700, value));
  64     pa_assert(s->sem != SEM_FAILED);
  65     return s;
  66 }
  67
  68 void pa_semaphore_free(pa_semaphore *s) {
  69     char fn[32];
  70
  71     pa_assert(s);
  72
  73     pa_assert_se(sem_close(s->sem) == 0);
  74     sem_name(fn, sizeof(fn), s->id);
  75     pa_assert_se(sem_unlink(fn) == 0);
  76     pa_xfree(s);
  77 }
  78
  79 void pa_semaphore_post(pa_semaphore *s) {
  80     pa_assert(s);
  81     pa_assert_se(sem_post(s->sem) == 0);
  82 }
  83
  84 void pa_semaphore_wait(pa_semaphore *s) {
  85     int ret;
  86
  87     pa_assert(s);
  88
  89     do {
  90         ret = sem_wait(s->sem);
  91     } while (ret < 0 && errno == EINTR);
  92
  93     pa_assert(ret == 0);
  94 }