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() */
32 static int thread_init_generation = 0;
33 
55 void
57 {
58  _dbus_assert (location_p != NULL);
59 
61  {
62  *location_p = NULL;
63  return;
64  }
65 
66  *location_p = _dbus_platform_rmutex_new ();
67 }
68 
79 void
81 {
82  _dbus_assert (location_p != NULL);
83 
85  {
86  *location_p = NULL;
87  return;
88  }
89 
90  *location_p = _dbus_platform_cmutex_new ();
91 }
92 
96 void
98 {
99  if (location_p == NULL)
100  return;
101 
102  if (*location_p != NULL)
103  _dbus_platform_rmutex_free (*location_p);
104 }
105 
109 void
111 {
112  if (location_p == NULL)
113  return;
114 
115  if (*location_p != NULL)
116  _dbus_platform_cmutex_free (*location_p);
117 }
118 
124 void
126 {
127  if (mutex == NULL)
128  return;
129 
130  _dbus_platform_rmutex_lock (mutex);
131 }
132 
138 void
140 {
141  if (mutex == NULL)
142  return;
143 
144  _dbus_platform_cmutex_lock (mutex);
145 }
146 
152 void
154 {
155  if (mutex == NULL)
156  return;
157 
158  _dbus_platform_rmutex_unlock (mutex);
159 }
160 
166 void
168 {
169  if (mutex == NULL)
170  return;
171 
172  _dbus_platform_cmutex_unlock (mutex);
173 }
174 
183 DBusCondVar *
185 {
187  return NULL;
188 
189  return _dbus_platform_condvar_new ();
190 }
191 
192 
201 void
203 {
204  _dbus_assert (location_p != NULL);
205 
206  *location_p = _dbus_condvar_new();
207 }
208 
209 
214 void
216 {
217  if (cond == NULL)
218  return;
219 
220  _dbus_platform_condvar_free (cond);
221 }
222 
226 void
228 {
229  if (location_p == NULL)
230  return;
231 
232  if (*location_p != NULL)
233  _dbus_platform_condvar_free (*location_p);
234 }
235 
242 void
244  DBusCMutex *mutex)
245 {
246  if (cond == NULL || mutex == NULL)
247  return;
248 
249  _dbus_platform_condvar_wait (cond, mutex);
250 }
251 
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 
280 void
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() */
290 static DBusRMutex *global_locks[_DBUS_N_GLOBAL_LOCKS] = { NULL };
291 
292 static void
293 shutdown_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 
305 static dbus_bool_t
306 init_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 
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 &&
348  return FALSE;
349 
350  _dbus_platform_rmutex_lock (global_locks[lock]);
351  return TRUE;
352 }
353 
354 void
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 
396 {
398 
399  if (thread_init_generation == _dbus_current_generation)
400  {
402  return TRUE;
403  }
404 
406  !init_global_locks ())
407  {
409  return FALSE;
410  }
411 
412  thread_init_generation = _dbus_current_generation;
413 
415  return TRUE;
416 }
417 
418 
419 
420 /* Default thread implemenation */
421 
443 {
444  return dbus_threads_init (NULL);
445 }
446 
447 
450 #ifdef DBUS_ENABLE_EMBEDDED_TESTS
451 
452 #endif /* DBUS_ENABLE_EMBEDDED_TESTS */
Functions that must be implemented to make the D-Bus library thread-aware.
Definition: dbus-threads.h:154
#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:243
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:264
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:56
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:153
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_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:37
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's been called.
Definition: dbus-memory.c:790
void _dbus_cmutex_unlock(DBusCMutex *mutex)
Unlocks a mutex.
Definition: dbus-threads.c:167
#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:202
#define _dbus_assert(condition)
Aborts with an error message if the condition is false.
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
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:184
void _dbus_rmutex_free_at_location(DBusRMutex **location_p)
Frees a DBusRMutex; does nothing if passed a NULL pointer.
Definition: dbus-threads.c:97
void _dbus_cmutex_lock(DBusCMutex *mutex)
Locks a mutex.
Definition: dbus-threads.c:139
void _dbus_rmutex_lock(DBusRMutex *mutex)
Locks a mutex.
Definition: dbus-threads.c:125
#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:110
dbus_bool_t dbus_threads_init(const DBusThreadFunctions *functions)
Initializes threads, like dbus_threads_init_default().
Definition: dbus-threads.c:395
dbus_bool_t dbus_threads_init_default(void)
Initializes threads.
Definition: dbus-threads.c:442
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
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