D-Bus: dbus-threads.c Source File

D-Bus 1.16.2

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 * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
7 *
8 * Licensed under the Academic Free License version 2.1
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 *
24 */
25#include <config.h>
26#include "dbus-threads.h"
27#include "dbus-internals.h"
28#include "dbus-threads-internal.h"
29#include "dbus-list.h"
30
31/* Protected by _dbus_threads_lock_platform_specific() */
32static int thread_init_generation = 0;
33
55void
56_dbus_rmutex_new_at_location (DBusRMutex **location_p)
57{
58 _dbus_assert (location_p != NULL);
59
60 if (!dbus_threads_init_default ())
61 {
62 *location_p = NULL;
63 return;
64 }
65
66 *location_p = _dbus_platform_rmutex_new ();
67}
68
79void
80_dbus_cmutex_new_at_location (DBusCMutex **location_p)
81{
82 _dbus_assert (location_p != NULL);
83
84 if (!dbus_threads_init_default ())
85 {
86 *location_p = NULL;
87 return;
88 }
89
90 *location_p = _dbus_platform_cmutex_new ();
91}
92
96void
97_dbus_rmutex_free_at_location (DBusRMutex **location_p)
98{
99 if (location_p == NULL)
100 return;
101
102 if (*location_p != NULL)
103 _dbus_platform_rmutex_free (*location_p);
104}
105
109void
110_dbus_cmutex_free_at_location (DBusCMutex **location_p)
111{
112 if (location_p == NULL)
113 return;
114
115 if (*location_p != NULL)
116 _dbus_platform_cmutex_free (*location_p);
117}
118
124void
125_dbus_rmutex_lock (DBusRMutex *mutex)
126{
127 if (mutex == NULL)
128 return;
129
130 _dbus_platform_rmutex_lock (mutex);
131}
132
138void
139_dbus_cmutex_lock (DBusCMutex *mutex)
140{
141 if (mutex == NULL)
142 return;
143
144 _dbus_platform_cmutex_lock (mutex);
145}
146
152void
153_dbus_rmutex_unlock (DBusRMutex *mutex)
154{
155 if (mutex == NULL)
156 return;
157
158 _dbus_platform_rmutex_unlock (mutex);
159}
160
166void
167_dbus_cmutex_unlock (DBusCMutex *mutex)
168{
169 if (mutex == NULL)
170 return;
171
172 _dbus_platform_cmutex_unlock (mutex);
173}
174
183 DBusCondVar *
184_dbus_condvar_new (void)
185{
186 if (!dbus_threads_init_default ())
187 return NULL;
188
189 return _dbus_platform_condvar_new ();
190}
191
192
201void
202_dbus_condvar_new_at_location (DBusCondVar **location_p)
203{
204 _dbus_assert (location_p != NULL);
205
206 *location_p = _dbus_condvar_new();
207}
208
209
214void
215_dbus_condvar_free (DBusCondVar *cond)
216{
217 if (cond == NULL)
218 return;
219
220 _dbus_platform_condvar_free (cond);
221}
222
226void
227_dbus_condvar_free_at_location (DBusCondVar **location_p)
228{
229 if (location_p == NULL)
230 return;
231
232 if (*location_p != NULL)
233 _dbus_platform_condvar_free (*location_p);
234}
235
242void
243_dbus_condvar_wait (DBusCondVar *cond,
244 DBusCMutex *mutex)
245{
246 if (cond == NULL || mutex == NULL)
247 return;
248
249 _dbus_platform_condvar_wait (cond, mutex);
250}
251
263dbus_bool_t
264_dbus_condvar_wait_timeout (DBusCondVar *cond,
265 DBusCMutex *mutex,
266 int timeout_milliseconds)
267{
268 if (cond == NULL || mutex == NULL)
269 return TRUE;
270
271 return _dbus_platform_condvar_wait_timeout (cond, mutex,
272 timeout_milliseconds);
273}
274
280void
281_dbus_condvar_wake_one (DBusCondVar *cond)
282{
283 if (cond == NULL)
284 return;
285
286 _dbus_platform_condvar_wake_one (cond);
287}
288
289/* Protected by _dbus_threads_lock_platform_specific() */
290static DBusRMutex *global_locks[_DBUS_N_GLOBAL_LOCKS] = { NULL };
291
292static void
293shutdown_global_locks (void *nil)
294{
295 int i;
296
297 for (i = 0; i < _DBUS_N_GLOBAL_LOCKS; i++)
298 {
299 _dbus_assert (global_locks[i] != NULL);
300 _dbus_platform_rmutex_free (global_locks[i]);
301 global_locks[i] = NULL;
302 }
303}
304
305static dbus_bool_t
306init_global_locks (void)
307{
308 int i;
309 dbus_bool_t ok;
310
311 for (i = 0; i < _DBUS_N_GLOBAL_LOCKS; i++)
312 {
313 _dbus_assert (global_locks[i] == NULL);
314
315 global_locks[i] = _dbus_platform_rmutex_new ();
316
317 if (global_locks[i] == NULL)
318 goto failed;
319 }
320
321 _dbus_platform_rmutex_lock (global_locks[_DBUS_LOCK_shutdown_funcs]);
322 ok = _dbus_register_shutdown_func_unlocked (shutdown_global_locks, NULL);
323 _dbus_platform_rmutex_unlock (global_locks[_DBUS_LOCK_shutdown_funcs]);
324
325 if (!ok)
326 goto failed;
327
328 return TRUE;
329
330 failed:
331 for (i = i - 1; i >= 0; i--)
332 {
333 _dbus_platform_rmutex_free (global_locks[i]);
334 global_locks[i] = NULL;
335 }
336
337 return FALSE;
338}
339
340dbus_bool_t
341_dbus_lock (DBusGlobalLock lock)
342{
343 _dbus_assert (lock >= 0);
344 _dbus_assert (lock < _DBUS_N_GLOBAL_LOCKS);
345
346 if (thread_init_generation != _dbus_current_generation &&
347 !dbus_threads_init_default ())
348 return FALSE;
349
350 _dbus_platform_rmutex_lock (global_locks[lock]);
351 return TRUE;
352}
353
354void
355_dbus_unlock (DBusGlobalLock lock)
356{
357 _dbus_assert (lock >= 0);
358 _dbus_assert (lock < _DBUS_N_GLOBAL_LOCKS);
359
360 _dbus_platform_rmutex_unlock (global_locks[lock]);
361}
362 /* end of internals */
364
394dbus_bool_t
395dbus_threads_init (const DBusThreadFunctions *functions)
396{
397 _dbus_threads_lock_platform_specific ();
398
399 if (thread_init_generation == _dbus_current_generation)
400 {
401 _dbus_threads_unlock_platform_specific ();
402 return TRUE;
403 }
404
405 if (!_dbus_threads_init_platform_specific() ||
406 !init_global_locks ())
407 {
408 _dbus_threads_unlock_platform_specific ();
409 return FALSE;
410 }
411
412 thread_init_generation = _dbus_current_generation;
413
414 _dbus_threads_unlock_platform_specific ();
415 return TRUE;
416}
417
418
419
420/* Default thread implemenation */
421
441dbus_bool_t
442dbus_threads_init_default (void)
443{
444 return dbus_threads_init (NULL);
445}
446
447
450#ifdef DBUS_ENABLE_EMBEDDED_TESTS
451
452#endif /* DBUS_ENABLE_EMBEDDED_TESTS */
_dbus_assert
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
Definition dbus-internals.h:153
NULL
#define NULL
A null pointer, defined appropriately for C or C++.
Definition dbus-macros.h:51
TRUE
#define TRUE
Expands to "1".
Definition dbus-macros.h:41
FALSE
#define FALSE
Expands to "0".
Definition dbus-macros.h:44
_dbus_current_generation
int _dbus_current_generation
_dbus_current_generation is used to track each time that dbus_shutdown() is called,...
Definition dbus-memory.c:790
_dbus_threads_lock_platform_specific
void _dbus_threads_lock_platform_specific(void)
Lock a static mutex used to protect _dbus_threads_init_platform_specific().
Definition dbus-sysdeps-pthread.c:296
_dbus_threads_unlock_platform_specific
void _dbus_threads_unlock_platform_specific(void)
Undo _dbus_threads_lock_platform_specific().
Definition dbus-sysdeps-pthread.c:302
_dbus_threads_init_platform_specific
dbus_bool_t _dbus_threads_init_platform_specific(void)
Initialize threads as in dbus_threads_init_default(), appropriately for the platform.
Definition dbus-sysdeps-pthread.c:281
_dbus_rmutex_new_at_location
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:56
_dbus_cmutex_free_at_location
void _dbus_cmutex_free_at_location(DBusCMutex **location_p)
Frees a DBusCMutex; does nothing if passed a NULL pointer.
Definition dbus-threads.c:110
_dbus_condvar_new
DBusCondVar * _dbus_condvar_new(void)
Creates a new condition variable using the function supplied to dbus_threads_init(),...
Definition dbus-threads.c:184
_dbus_condvar_free_at_location
void _dbus_condvar_free_at_location(DBusCondVar **location_p)
Frees a condition variable; does nothing if passed a NULL pointer.
Definition dbus-threads.c:227
_dbus_rmutex_unlock
void _dbus_rmutex_unlock(DBusRMutex *mutex)
Unlocks a mutex.
Definition dbus-threads.c:153
_dbus_condvar_wait
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:243
_dbus_condvar_new_at_location
void _dbus_condvar_new_at_location(DBusCondVar **location_p)
This does the same thing as _dbus_condvar_new.
Definition dbus-threads.c:202
_dbus_cmutex_new_at_location
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:80
_dbus_condvar_wake_one
void _dbus_condvar_wake_one(DBusCondVar *cond)
If there are threads waiting on the condition variable, wake up exactly one.
Definition dbus-threads.c:281
_dbus_condvar_wait_timeout
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,...
Definition dbus-threads.c:264
_dbus_cmutex_lock
void _dbus_cmutex_lock(DBusCMutex *mutex)
Locks a mutex.
Definition dbus-threads.c:139
_dbus_cmutex_unlock
void _dbus_cmutex_unlock(DBusCMutex *mutex)
Unlocks a mutex.
Definition dbus-threads.c:167
_dbus_rmutex_free_at_location
void _dbus_rmutex_free_at_location(DBusRMutex **location_p)
Frees a DBusRMutex; does nothing if passed a NULL pointer.
Definition dbus-threads.c:97
_dbus_rmutex_lock
void _dbus_rmutex_lock(DBusRMutex *mutex)
Locks a mutex.
Definition dbus-threads.c:125
_dbus_condvar_free
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:215
dbus_threads_init_default
dbus_bool_t dbus_threads_init_default(void)
Initializes threads.
Definition dbus-threads.c:442
dbus_threads_init
dbus_bool_t dbus_threads_init(const DBusThreadFunctions *functions)
Initializes threads, like dbus_threads_init_default().
Definition dbus-threads.c:395
DBusCMutex
Definition dbus-sysdeps-pthread.c:55
DBusCondVar
Definition dbus-sysdeps-pthread.c:59
DBusRMutex
Definition dbus-sysdeps-pthread.c:51
DBusThreadFunctions
Functions that must be implemented to make the D-Bus library thread-aware.
Definition dbus-threads.h:155