code.delx.au - pulseaudio/blob - src/pulsecore/thread-posix.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   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 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, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <assert.h>
  27 #include <pthread.h>
  28 #include <sched.h>
  29 #include <errno.h>
  30
  31 #include <atomic_ops.h>
  32
  33 #include <pulse/xmalloc.h>
  34 #include <pulsecore/mutex.h>
  35
  36 #include "thread.h"
  37
  38 #define ASSERT_SUCCESS(x) do { \
  39     int _r = (x); \
  40     assert(_r == 0); \
  41 } while(0)
  42
  43 struct pa_thread {
  44     pthread_t id;
  45     pa_thread_func_t thread_func;
  46     void *userdata;
  47     AO_t running;
  48 };
  49
  50 struct pa_tls {
  51     pthread_key_t key;
  52 };
  53
  54 static pa_tls *thread_tls;
  55 static pthread_once_t thread_tls_once = PTHREAD_ONCE_INIT;
  56
  57 static pa_mutex *once_mutex;
  58 static pthread_once_t thread_once_once = PTHREAD_ONCE_INIT;
  59
  60 static void tls_free_cb(void *p) {
  61     pa_thread *t = p;
  62
  63     assert(t);
  64
  65     if (!t->thread_func)
  66         /* This is a foreign thread, we need to free the struct */
  67         pa_xfree(t);
  68 }
  69
  70 static void thread_tls_once_func(void) {
  71     thread_tls = pa_tls_new(tls_free_cb);
  72     assert(thread_tls);
  73 }
  74
  75 static void* internal_thread_func(void *userdata) {
  76     pa_thread *t = userdata;
  77     assert(t);
  78
  79     t->id = pthread_self();
  80
  81     ASSERT_SUCCESS(pthread_once(&thread_tls_once, thread_tls_once_func));
  82     pa_tls_set(thread_tls, t);
  83
  84     AO_fetch_and_add1_full(&t->running);
  85     t->thread_func(t->userdata);
  86     AO_fetch_and_add_full(&t->running, (AO_t) -2);
  87
  88     return NULL;
  89 }
  90
  91 pa_thread* pa_thread_new(pa_thread_func_t thread_func, void *userdata) {
  92     pa_thread *t;
  93
  94     assert(thread_func);
  95
  96     t = pa_xnew(pa_thread, 1);
  97     t->thread_func = thread_func;
  98     t->userdata = userdata;
  99     AO_store_full(&t->running, 0);
 100
 101     if (pthread_create(&t->id, NULL, internal_thread_func, t) < 0) {
 102         pa_xfree(t);
 103         return NULL;
 104     }
 105
 106     AO_fetch_and_add1_full(&t->running);
 107
 108     return t;
 109 }
 110
 111 int pa_thread_is_running(pa_thread *t) {
 112     AO_t r;
 113     assert(t);
 114
 115     if (!t->thread_func) {
 116         /* Mhmm, this is a foreign thread, t->running is not
 117          * necessarily valid. We misuse pthread_getschedparam() to
 118          * check if the thread is valid. This might not be portable. */
 119
 120         int policy;
 121         struct sched_param param;
 122
 123         return pthread_getschedparam(t->id, &policy, &param) >= 0 || errno != ESRCH;
 124     }
 125
 126     r = AO_load_full(&t->running);
 127     return r == 1 || r == 2;
 128 }
 129
 130 void pa_thread_free(pa_thread *t) {
 131     assert(t);
 132
 133     pa_thread_join(t);
 134     pa_xfree(t);
 135 }
 136
 137 int pa_thread_join(pa_thread *t) {
 138     assert(t);
 139
 140     return pthread_join(t->id, NULL);
 141 }
 142
 143 pa_thread* pa_thread_self(void) {
 144     pa_thread *t;
 145
 146     ASSERT_SUCCESS(pthread_once(&thread_tls_once, thread_tls_once_func));
 147
 148     if ((t = pa_tls_get(thread_tls)))
 149         return t;
 150
 151     /* This is a foreign thread, let's create a pthread structure to
 152      * make sure that we can always return a sensible pointer */
 153
 154     t = pa_xnew(pa_thread, 1);
 155     t->id = pthread_self();
 156     t->thread_func = NULL;
 157     t->userdata = NULL;
 158     AO_store_full(&t->running, 1);
 159
 160     pa_tls_set(thread_tls, t);
 161
 162     return t;
 163 }
 164
 165 void pa_thread_yield(void) {
 166 #ifdef HAVE_PTHREAD_YIELD
 167     pthread_yield();
 168 #else
 169     ASSERT_SUCCESS(sched_yield());
 170 #endif
 171 }
 172
 173 static void thread_once_once_func(void) {
 174     once_mutex = pa_mutex_new(0);
 175     assert(once_mutex);
 176 }
 177
 178 void pa_thread_once(pa_thread_once_t *control, pa_thread_once_func_t once_func) {
 179     assert(control);
 180     assert(once_func);
 181
 182     ASSERT_SUCCESS(pthread_once(&thread_once_once, thread_once_once_func));
 183
 184     pa_mutex_lock(once_mutex);
 185
 186     if (*control == PA_THREAD_ONCE_INIT) {
 187         *control = ~PA_THREAD_ONCE_INIT;
 188         pa_mutex_unlock(once_mutex);
 189         once_func();
 190     } else
 191         pa_mutex_unlock(once_mutex);
 192 }
 193
 194 pa_tls* pa_tls_new(pa_free_cb_t free_cb) {
 195     pa_tls *t;
 196
 197     t = pa_xnew(pa_tls, 1);
 198
 199     if (pthread_key_create(&t->key, free_cb) < 0) {
 200         pa_xfree(t);
 201         return NULL;
 202     }
 203
 204     return t;
 205 }
 206
 207 void pa_tls_free(pa_tls *t) {
 208     assert(t);
 209
 210     ASSERT_SUCCESS(pthread_key_delete(t->key));
 211     pa_xfree(t);
 212 }
 213
 214 void *pa_tls_get(pa_tls *t) {
 215     assert(t);
 216
 217     return pthread_getspecific(t->key);
 218 }
 219
 220 void *pa_tls_set(pa_tls *t, void *userdata) {
 221     void *r;
 222
 223     r = pthread_getspecific(t->key);
 224     ASSERT_SUCCESS(pthread_setspecific(t->key, userdata));
 225     return r;
 226 }
 227