D-Bus  1.13.7
dbus-threads.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-threads.h D-Bus threads handling
3  *
4  * Copyright (C) 2002, 2003, 2006 Red Hat Inc.
5  *
6  * Licensed under the Academic Free License version 2.1
7  *
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.
12  *
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.
17  *
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  *
22  */
23 #include <config.h>
24 #include "dbus-threads.h"
25 #include "dbus-internals.h"
26 #include "dbus-threads-internal.h"
27 #include "dbus-list.h"
28 
29 static int thread_init_generation = 0;
30 
52 void
54 {
55  _dbus_assert (location_p != NULL);
56 
58  {
59  *location_p = NULL;
60  return;
61  }
62 
63  *location_p = _dbus_platform_rmutex_new ();
64 }
65 
76 void
78 {
79  _dbus_assert (location_p != NULL);
80 
82  {
83  *location_p = NULL;
84  return;
85  }
86 
87  *location_p = _dbus_platform_cmutex_new ();
88 }
89 
93 void
95 {
96  if (location_p == NULL)
97  return;
98 
99  if (*location_p != NULL)
100  _dbus_platform_rmutex_free (*location_p);
101 }
102 
106 void
108 {
109  if (location_p == NULL)
110  return;
111 
112  if (*location_p != NULL)
113  _dbus_platform_cmutex_free (*location_p);
114 }
115 
121 void
123 {
124  if (mutex == NULL)
125  return;
126 
127  _dbus_platform_rmutex_lock (mutex);
128 }
129 
135 void
137 {
138  if (mutex == NULL)
139  return;
140 
141  _dbus_platform_cmutex_lock (mutex);
142 }
143 
149 void
151 {
152  if (mutex == NULL)
153  return;
154 
155  _dbus_platform_rmutex_unlock (mutex);
156 }
157 
163 void
165 {
166  if (mutex == NULL)
167  return;
168 
169  _dbus_platform_cmutex_unlock (mutex);
170 }
171 
180 DBusCondVar *
182 {
184  return NULL;
185 
186  return _dbus_platform_condvar_new ();
187 }
188 
189 
198 void
200 {
201  _dbus_assert (location_p != NULL);
202 
203  *location_p = _dbus_condvar_new();
204 }
205 
206 
211 void
213 {
214  if (cond == NULL)
215  return;
216 
217  _dbus_platform_condvar_free (cond);
218 }
219 
223 void
225 {
226  if (location_p == NULL)
227  return;
228 
229  if (*location_p != NULL)
230  _dbus_platform_condvar_free (*location_p);
231 }
232 
239 void
241  DBusCMutex *mutex)
242 {
243  if (cond == NULL || mutex == NULL)
244  return;
245 
246  _dbus_platform_condvar_wait (cond, mutex);
247 }
248 
262  DBusCMutex *mutex,
263  int timeout_milliseconds)
264 {
265  if (cond == NULL || mutex == NULL)
266  return TRUE;
267 
268  return _dbus_platform_condvar_wait_timeout (cond, mutex,
269  timeout_milliseconds);
270 }
271 
277 void
279 {
280  if (cond == NULL)
281  return;
282 
283  _dbus_platform_condvar_wake_one (cond);
284 }
285 
286 static DBusRMutex *global_locks[_DBUS_N_GLOBAL_LOCKS] = { NULL };
287 
288 static void
289 shutdown_global_locks (void *nil)
290 {
291  int i;
292 
293  for (i = 0; i < _DBUS_N_GLOBAL_LOCKS; i++)
294  {
295  _dbus_assert (global_locks[i] != NULL);
296  _dbus_platform_rmutex_free (global_locks[i]);
297  global_locks[i] = NULL;
298  }
299 }
300 
301 static dbus_bool_t
302 init_global_locks (void)
303 {
304  int i;
305  dbus_bool_t ok;
306 
307  for (i = 0; i < _DBUS_N_GLOBAL_LOCKS; i++)
308  {
309  _dbus_assert (global_locks[i] == NULL);
310 
311  global_locks[i] = _dbus_platform_rmutex_new ();
312 
313  if (global_locks[i] == NULL)
314  goto failed;
315  }
316 
317  _dbus_platform_rmutex_lock (global_locks[_DBUS_LOCK_shutdown_funcs]);
318  ok = _dbus_register_shutdown_func_unlocked (shutdown_global_locks, NULL);
319  _dbus_platform_rmutex_unlock (global_locks[_DBUS_LOCK_shutdown_funcs]);
320 
321  if (!ok)
322  goto failed;
323 
324  return TRUE;
325 
326  failed:
327  for (i = i - 1; i >= 0; i--)
328  {
329  _dbus_platform_rmutex_free (global_locks[i]);
330  global_locks[i] = NULL;
331  }
332 
333  return FALSE;
334 }
335 
337 _dbus_lock (DBusGlobalLock lock)
338 {
339  _dbus_assert (lock >= 0);
340  _dbus_assert (lock < _DBUS_N_GLOBAL_LOCKS);
341 
342  if (thread_init_generation != _dbus_current_generation &&
344  return FALSE;
345 
346  _dbus_platform_rmutex_lock (global_locks[lock]);
347  return TRUE;
348 }
349 
350 void
351 _dbus_unlock (DBusGlobalLock lock)
352 {
353  _dbus_assert (lock >= 0);
354  _dbus_assert (lock < _DBUS_N_GLOBAL_LOCKS);
355 
356  _dbus_platform_rmutex_unlock (global_locks[lock]);
357 }
358  /* end of internals */
360 
392 {
394 
395  if (thread_init_generation == _dbus_current_generation)
396  {
398  return TRUE;
399  }
400 
402  !init_global_locks ())
403  {
405  return FALSE;
406  }
407 
408  thread_init_generation = _dbus_current_generation;
409 
411  return TRUE;
412 }
413 
414 
415 
416 /* Default thread implemenation */
417 
439 {
440  return dbus_threads_init (NULL);
441 }
442 
443 
446 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
447 
449 _dbus_threads_init_debug (void)
450 {
451  return dbus_threads_init (NULL);
452 }
453 
454 #endif /* DBUS_ENABLE_EMBEDDED_TESTS */
Functions that must be implemented to make the D-Bus library thread-aware.
Definition: dbus-threads.h:152
#define NULL
A null pointer, defined appropriately for C or C++.
void _dbus_condvar_wait(DBusCondVar *cond, DBusCMutex *mutex)
Atomically unlocks the mutex and waits for the conditions variable to be signalled.
Definition: dbus-threads.c:240
dbus_bool_t _dbus_condvar_wait_timeout(DBusCondVar *cond, DBusCMutex *mutex, int timeout_milliseconds)
Atomically unlocks the mutex and waits for the conditions variable to be signalled, or for a timeout.
Definition: dbus-threads.c:261
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
dbus_bool_t _dbus_threads_init_platform_specific(void)
Initialize threads as in dbus_threads_init_default(), appropriately for the platform.
void _dbus_rmutex_new_at_location(DBusRMutex **location_p)
Creates a new mutex or creates a no-op mutex if threads are not initialized.
Definition: dbus-threads.c:53
pthread_mutex_t lock
the lock
void _dbus_threads_unlock_platform_specific(void)
Undo _dbus_threads_lock_platform_specific().
void _dbus_threads_lock_platform_specific(void)
Lock a static mutex used to protect _dbus_threads_init_platform_specific().
void _dbus_rmutex_unlock(DBusRMutex *mutex)
Unlocks a mutex.
Definition: dbus-threads.c:150
void _dbus_condvar_free(DBusCondVar *cond)
Frees a conditional variable created with dbus_condvar_new(); does nothing if passed a NULL pointer...
Definition: dbus-threads.c:212
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
int _dbus_current_generation
_dbus_current_generation is used to track each time that dbus_shutdown() is called, so we can reinit things after it&#39;s been called.
Definition: dbus-memory.c:783
void _dbus_cmutex_unlock(DBusCMutex *mutex)
Unlocks a mutex.
Definition: dbus-threads.c:164
#define TRUE
Expands to "1".
void _dbus_condvar_new_at_location(DBusCondVar **location_p)
This does the same thing as _dbus_condvar_new.
Definition: dbus-threads.c:199
void _dbus_condvar_wake_one(DBusCondVar *cond)
If there are threads waiting on the condition variable, wake up exactly one.
Definition: dbus-threads.c:278
DBusCondVar * _dbus_condvar_new(void)
Creates a new condition variable using the function supplied to dbus_threads_init(), or creates a no-op condition variable if threads are not initialized.
Definition: dbus-threads.c:181
void _dbus_rmutex_free_at_location(DBusRMutex **location_p)
Frees a DBusRMutex; does nothing if passed a NULL pointer.
Definition: dbus-threads.c:94
void _dbus_cmutex_lock(DBusCMutex *mutex)
Locks a mutex.
Definition: dbus-threads.c:136
void _dbus_rmutex_lock(DBusRMutex *mutex)
Locks a mutex.
Definition: dbus-threads.c:122
#define FALSE
Expands to "0".
void _dbus_cmutex_free_at_location(DBusCMutex **location_p)
Frees a DBusCMutex; does nothing if passed a NULL pointer.
Definition: dbus-threads.c:107
dbus_bool_t dbus_threads_init(const DBusThreadFunctions *functions)
Initializes threads, like dbus_threads_init_default().
Definition: dbus-threads.c:391
dbus_bool_t dbus_threads_init_default(void)
Initializes threads.
Definition: dbus-threads.c:438
void _dbus_condvar_free_at_location(DBusCondVar **location_p)
Frees a condition variable; does nothing if passed a NULL pointer.
Definition: dbus-threads.c:224
void _dbus_cmutex_new_at_location(DBusCMutex **location_p)
Creates a new mutex or creates a no-op mutex if threads are not initialized.
Definition: dbus-threads.c:77