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
34 struct pa_mutex {
35 pthread_mutex_t mutex;
36 };
37
38 struct pa_cond {
39 pthread_cond_t cond;
40 };
41
pa_mutex_new(bool recursive, bool inherit_priority)42 pa_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
pa_mutex_free(pa_mutex *m)82 void 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
pa_mutex_lock(pa_mutex *m)89 void pa_mutex_lock(pa_mutex *m) {
90 pa_assert(m);
91
92 pa_assert_se(pthread_mutex_lock(&m->mutex) == 0);
93 }
94
pa_mutex_try_lock(pa_mutex *m)95 bool 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
pa_mutex_unlock(pa_mutex *m)107 void 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
pa_cond_new(void)118 pa_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
pa_cond_free(pa_cond *c)126 void 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
pa_cond_signal(pa_cond *c, int broadcast)133 void 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
pa_cond_wait(pa_cond *c, pa_mutex *m)142 int 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
pa_static_mutex_get(pa_static_mutex *s, bool recursive, bool inherit_priority)149 pa_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