1/***
2  This file is part of PulseAudio.
3
4  Copyright 2006 Lennart Poettering
5
6  PulseAudio is free software; you can redistribute it and/or modify
7  it under the terms of the GNU Lesser General Public License as published
8  by the Free Software Foundation; either version 2.1 of the License,
9  or (at your option) any later version.
10
11  PulseAudio is distributed in the hope that it will be useful, but
12  WITHOUT ANY WARRANTY; without even the implied warranty of
13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  General Public License for more details.
15
16  You should have received a copy of the GNU Lesser General Public License
17  along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
18***/
19
20#ifdef HAVE_CONFIG_H
21#include <config.h>
22#endif
23
24#include <pthread.h>
25#include <errno.h>
26
27#include <pulse/xmalloc.h>
28
29#include <pulsecore/core-error.h>
30#include <pulsecore/macro.h>
31
32#include "mutex.h"
33
34struct pa_mutex {
35    pthread_mutex_t mutex;
36};
37
38struct pa_cond {
39    pthread_cond_t cond;
40};
41
42pa_mutex* pa_mutex_new(bool recursive, bool inherit_priority) {
43    pa_mutex *m;
44    pthread_mutexattr_t attr;
45#ifdef HAVE_PTHREAD_PRIO_INHERIT
46    int r;
47#endif
48
49    pa_assert_se(pthread_mutexattr_init(&attr) == 0);
50
51    if (recursive)
52        pa_assert_se(pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
53
54#ifdef HAVE_PTHREAD_PRIO_INHERIT
55    if (inherit_priority) {
56        r = pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT);
57        pa_assert(r == 0 || r == ENOTSUP);
58    }
59#endif
60
61    m = pa_xnew(pa_mutex, 1);
62
63#ifndef HAVE_PTHREAD_PRIO_INHERIT
64    pa_assert_se(pthread_mutex_init(&m->mutex, &attr) == 0);
65
66#else
67    if ((r = pthread_mutex_init(&m->mutex, &attr))) {
68
69        /* If this failed, then this was probably due to non-available
70         * priority inheritance. In which case we fall back to normal
71         * mutexes. */
72        pa_assert(r == ENOTSUP && inherit_priority);
73
74        pa_assert_se(pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_NONE) == 0);
75        pa_assert_se(pthread_mutex_init(&m->mutex, &attr) == 0);
76    }
77#endif
78
79    return m;
80}
81
82void pa_mutex_free(pa_mutex *m) {
83    pa_assert(m);
84
85    pa_assert_se(pthread_mutex_destroy(&m->mutex) == 0);
86    pa_xfree(m);
87}
88
89void pa_mutex_lock(pa_mutex *m) {
90    pa_assert(m);
91
92    pa_assert_se(pthread_mutex_lock(&m->mutex) == 0);
93}
94
95bool pa_mutex_try_lock(pa_mutex *m) {
96    int r;
97    pa_assert(m);
98
99    if ((r = pthread_mutex_trylock(&m->mutex)) != 0) {
100        pa_assert(r == EBUSY);
101        return false;
102    }
103
104    return true;
105}
106
107void pa_mutex_unlock(pa_mutex *m) {
108    int err;
109
110    pa_assert(m);
111
112    if ((err = pthread_mutex_unlock(&m->mutex)) != 0) {
113        pa_log_error("pthread_mutex_unlock() failed: %s", pa_cstrerror(err));
114        pa_assert_not_reached();
115    }
116}
117
118pa_cond *pa_cond_new(void) {
119    pa_cond *c;
120
121    c = pa_xnew(pa_cond, 1);
122    pa_assert_se(pthread_cond_init(&c->cond, NULL) == 0);
123    return c;
124}
125
126void pa_cond_free(pa_cond *c) {
127    pa_assert(c);
128
129    pa_assert_se(pthread_cond_destroy(&c->cond) == 0);
130    pa_xfree(c);
131}
132
133void pa_cond_signal(pa_cond *c, int broadcast) {
134    pa_assert(c);
135
136    if (broadcast)
137        pa_assert_se(pthread_cond_broadcast(&c->cond) == 0);
138    else
139        pa_assert_se(pthread_cond_signal(&c->cond) == 0);
140}
141
142int pa_cond_wait(pa_cond *c, pa_mutex *m) {
143    pa_assert(c);
144    pa_assert(m);
145
146    return pthread_cond_wait(&c->cond, &m->mutex);
147}
148
149pa_mutex* pa_static_mutex_get(pa_static_mutex *s, bool recursive, bool inherit_priority) {
150    pa_mutex *m;
151
152    pa_assert(s);
153
154    /* First, check if already initialized and short cut */
155    if ((m = pa_atomic_ptr_load(&s->ptr)))
156        return m;
157
158    /* OK, not initialized, so let's allocate, and fill in */
159    m = pa_mutex_new(recursive, inherit_priority);
160    if ((pa_atomic_ptr_cmpxchg(&s->ptr, NULL, m)))
161        return m;
162
163    pa_mutex_free(m);
164
165    /* Him, filling in failed, so someone else must have filled in
166     * already */
167    pa_assert_se(m = pa_atomic_ptr_load(&s->ptr));
168    return m;
169}
170