1 /* -*- mode: C; c-file-style: "gnu" -*- */
2 /* dbus-sysdeps-pthread.c Implements threads using pthreads (internal to libdbus)
4 * Copyright (C) 2002, 2003, 2006 Red Hat, Inc.
6 * Licensed under the Academic Free License version 2.1
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include "dbus-internals.h"
25 #include "dbus-sysdeps.h"
26 #include "dbus-threads.h"
42 #define DBUS_MUTEX(m) ((DBusMutex*) m)
43 #define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
45 #define DBUS_COND_VAR(c) ((DBusCondVar*) c)
46 #define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
49 #define PTHREAD_CHECK(func_name, result_or_call) do { \
50 int tmp = (result_or_call); \
52 _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s\n", \
53 func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME); \
58 _dbus_pthread_mutex_new (void)
60 DBusMutexPThread *pmutex;
63 pmutex = dbus_new (DBusMutexPThread, 1);
67 result = pthread_mutex_init (&pmutex->lock, NULL);
69 if (result == ENOMEM || result == EAGAIN)
76 PTHREAD_CHECK ("pthread_mutex_init", result);
82 /* There's no portable way to have a "null" pthread afaik so we
83 * can't set pmutex->holder to anything sensible. We only access it
84 * once the lock is held (which means we've set it).
87 return DBUS_MUTEX (pmutex);
91 _dbus_pthread_mutex_free (DBusMutex *mutex)
93 DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
95 _dbus_assert (pmutex->count == 0);
97 PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&pmutex->lock));
103 _dbus_pthread_mutex_lock (DBusMutex *mutex)
105 DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
106 pthread_t self = pthread_self ();
108 /* If the count is > 0 then someone had the lock, maybe us. If it is
109 * 0, then it might immediately change right after we read it,
110 * but it will be changed by another thread; i.e. if we read 0,
111 * we assume that this thread doesn't have the lock.
113 * Not 100% sure this is safe, but ... seems like it should be.
115 if (pmutex->count == 0)
117 /* We know we don't have the lock; someone may have the lock. */
119 PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
121 /* We now have the lock. Count must be 0 since it was before when we
122 * did not have the lock, and we have not changed it in this thread.
124 _dbus_assert (pmutex->count == 0);
126 pmutex->holder = self;
131 /* We know someone had the lock, possibly us. Thus
132 * pmutex->holder is not pointing to junk, though it may not be
133 * the lock holder anymore if the lock holder is not us.
134 * If the lock holder is us, then we definitely have the lock.
137 if (pthread_equal (pmutex->holder, self))
139 /* We already have the lock. */
143 /* Wait for the lock */
144 PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&pmutex->lock));
145 _dbus_assert (pmutex->count == 0);
153 _dbus_pthread_mutex_unlock (DBusMutex *mutex)
155 DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
157 _dbus_assert (pmutex->count > 0);
161 if (pmutex->count == 0)
162 PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&pmutex->lock));
164 /* We leave pmutex->holder set to ourselves, its content is undefined if count is 0 */
168 _dbus_pthread_condvar_new (void)
170 DBusCondVarPThread *pcond;
173 pcond = dbus_new (DBusCondVarPThread, 1);
177 result = pthread_cond_init (&pcond->cond, NULL);
179 if (result == EAGAIN || result == ENOMEM)
186 PTHREAD_CHECK ("pthread_cond_init", result);
189 return DBUS_COND_VAR (pcond);
193 _dbus_pthread_condvar_free (DBusCondVar *cond)
195 DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
197 PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&pcond->cond));
203 _dbus_pthread_condvar_wait (DBusCondVar *cond,
206 DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
207 DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
210 _dbus_assert (pmutex->count > 0);
211 _dbus_assert (pthread_equal (pmutex->holder, pthread_self ()));
213 old_count = pmutex->count;
215 PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&pcond->cond, &pmutex->lock));
216 _dbus_assert (pmutex->count == 0);
217 pmutex->count = old_count;
221 _dbus_pthread_condvar_wait_timeout (DBusCondVar *cond,
223 int timeout_milliseconds)
225 DBusMutexPThread *pmutex = DBUS_MUTEX_PTHREAD (mutex);
226 DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
227 struct timeval time_now;
228 struct timespec end_time;
232 _dbus_assert (pmutex->count > 0);
233 _dbus_assert (pthread_equal (pmutex->holder, pthread_self ()));
235 gettimeofday (&time_now, NULL);
237 end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
238 end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
239 if (end_time.tv_nsec > 1000*1000*1000)
241 end_time.tv_sec += 1;
242 end_time.tv_nsec -= 1000*1000*1000;
245 old_count = pmutex->count;
247 result = pthread_cond_timedwait (&pcond->cond, &pmutex->lock, &end_time);
249 if (result != ETIMEDOUT)
251 PTHREAD_CHECK ("pthread_cond_timedwait", result);
254 _dbus_assert (pmutex->count == 0);
255 pmutex->count = old_count;
257 /* return true if we did not time out */
258 return result != ETIMEDOUT;
262 _dbus_pthread_condvar_wake_one (DBusCondVar *cond)
264 DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
266 PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&pcond->cond));
270 _dbus_pthread_condvar_wake_all (DBusCondVar *cond)
272 DBusCondVarPThread *pcond = DBUS_COND_VAR_PTHREAD (cond);
274 PTHREAD_CHECK ("pthread_cond_broadcast", pthread_cond_broadcast (&pcond->cond));
277 static const DBusThreadFunctions pthread_functions =
279 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_NEW_MASK |
280 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_FREE_MASK |
281 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_LOCK_MASK |
282 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_UNLOCK_MASK |
283 DBUS_THREAD_FUNCTIONS_CONDVAR_NEW_MASK |
284 DBUS_THREAD_FUNCTIONS_CONDVAR_FREE_MASK |
285 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_MASK |
286 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_TIMEOUT_MASK |
287 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ONE_MASK|
288 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ALL_MASK,
289 NULL, NULL, NULL, NULL,
290 _dbus_pthread_condvar_new,
291 _dbus_pthread_condvar_free,
292 _dbus_pthread_condvar_wait,
293 _dbus_pthread_condvar_wait_timeout,
294 _dbus_pthread_condvar_wake_one,
295 _dbus_pthread_condvar_wake_all,
296 _dbus_pthread_mutex_new,
297 _dbus_pthread_mutex_free,
298 _dbus_pthread_mutex_lock,
299 _dbus_pthread_mutex_unlock
303 _dbus_threads_init_platform_specific (void)
305 return dbus_threads_init (&pthread_functions);