D-Bus  1.8.16
dbus-sysdeps-pthread.c
1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-sysdeps-pthread.c Implements threads using pthreads (internal to libdbus)
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 
24 #include <config.h>
25 #include "dbus-internals.h"
26 #include "dbus-sysdeps.h"
27 #include "dbus-threads.h"
28 
29 #include <sys/time.h>
30 #include <pthread.h>
31 #include <string.h>
32 
33 #ifdef HAVE_ERRNO_H
34 #include <errno.h>
35 #endif
36 
37 #include <config.h>
38 
39 #ifdef HAVE_MONOTONIC_CLOCK
40 /* Whether we have a "monotonic" clock; i.e. a clock not affected by
41  * changes in system time.
42  * This is initialized once in check_monotonic_clock below.
43  * https://bugs.freedesktop.org/show_bug.cgi?id=18121
44  */
45 static dbus_bool_t have_monotonic_clock = 0;
46 #endif
47 
48 struct DBusRMutex {
49  pthread_mutex_t lock;
50 };
51 
52 struct DBusCMutex {
53  pthread_mutex_t lock;
54 };
55 
56 struct DBusCondVar {
57  pthread_cond_t cond;
58 };
59 
60 #define DBUS_MUTEX(m) ((DBusMutex*) m)
61 #define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
62 
63 #define DBUS_COND_VAR(c) ((DBusCondVar*) c)
64 #define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
65 
66 
67 #ifdef DBUS_DISABLE_ASSERT
68 /* (tmp != 0) is a no-op usage to silence compiler */
69 #define PTHREAD_CHECK(func_name, result_or_call) \
70  do { int tmp = (result_or_call); if (tmp != 0) {;} } while (0)
71 #else
72 #define PTHREAD_CHECK(func_name, result_or_call) do { \
73  int tmp = (result_or_call); \
74  if (tmp != 0) { \
75  _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s\n", \
76  func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME); \
77  } \
78 } while (0)
79 #endif /* !DBUS_DISABLE_ASSERT */
80 
81 DBusCMutex *
82 _dbus_platform_cmutex_new (void)
83 {
84  DBusCMutex *pmutex;
85  int result;
86 
87  pmutex = dbus_new (DBusCMutex, 1);
88  if (pmutex == NULL)
89  return NULL;
90 
91  result = pthread_mutex_init (&pmutex->lock, NULL);
92 
93  if (result == ENOMEM || result == EAGAIN)
94  {
95  dbus_free (pmutex);
96  return NULL;
97  }
98  else
99  {
100  PTHREAD_CHECK ("pthread_mutex_init", result);
101  }
102 
103  return pmutex;
104 }
105 
106 DBusRMutex *
107 _dbus_platform_rmutex_new (void)
108 {
109  DBusRMutex *pmutex;
110  pthread_mutexattr_t mutexattr;
111  int result;
112 
113  pmutex = dbus_new (DBusRMutex, 1);
114  if (pmutex == NULL)
115  return NULL;
116 
117  pthread_mutexattr_init (&mutexattr);
118  pthread_mutexattr_settype (&mutexattr, PTHREAD_MUTEX_RECURSIVE);
119  result = pthread_mutex_init (&pmutex->lock, &mutexattr);
120  pthread_mutexattr_destroy (&mutexattr);
121 
122  if (result == ENOMEM || result == EAGAIN)
123  {
124  dbus_free (pmutex);
125  return NULL;
126  }
127  else
128  {
129  PTHREAD_CHECK ("pthread_mutex_init", result);
130  }
131 
132  return pmutex;
133 }
134 
135 void
136 _dbus_platform_cmutex_free (DBusCMutex *mutex)
137 {
138  PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
139  dbus_free (mutex);
140 }
141 
142 void
143 _dbus_platform_rmutex_free (DBusRMutex *mutex)
144 {
145  PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
146  dbus_free (mutex);
147 }
148 
149 void
150 _dbus_platform_cmutex_lock (DBusCMutex *mutex)
151 {
152  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
153 }
154 
155 void
156 _dbus_platform_rmutex_lock (DBusRMutex *mutex)
157 {
158  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
159 }
160 
161 void
162 _dbus_platform_cmutex_unlock (DBusCMutex *mutex)
163 {
164  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
165 }
166 
167 void
168 _dbus_platform_rmutex_unlock (DBusRMutex *mutex)
169 {
170  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
171 }
172 
173 DBusCondVar *
174 _dbus_platform_condvar_new (void)
175 {
176  DBusCondVar *pcond;
177  pthread_condattr_t attr;
178  int result;
179 
180  pcond = dbus_new (DBusCondVar, 1);
181  if (pcond == NULL)
182  return NULL;
183 
184  pthread_condattr_init (&attr);
185 #ifdef HAVE_MONOTONIC_CLOCK
186  if (have_monotonic_clock)
187  pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
188 #endif
189 
190  result = pthread_cond_init (&pcond->cond, &attr);
191  pthread_condattr_destroy (&attr);
192 
193  if (result == EAGAIN || result == ENOMEM)
194  {
195  dbus_free (pcond);
196  return NULL;
197  }
198  else
199  {
200  PTHREAD_CHECK ("pthread_cond_init", result);
201  }
202 
203  return pcond;
204 }
205 
206 void
207 _dbus_platform_condvar_free (DBusCondVar *cond)
208 {
209  PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&cond->cond));
210  dbus_free (cond);
211 }
212 
213 void
214 _dbus_platform_condvar_wait (DBusCondVar *cond,
215  DBusCMutex *mutex)
216 {
217  PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&cond->cond, &mutex->lock));
218 }
219 
221 _dbus_platform_condvar_wait_timeout (DBusCondVar *cond,
222  DBusCMutex *mutex,
223  int timeout_milliseconds)
224 {
225  struct timeval time_now;
226  struct timespec end_time;
227  int result;
228 
229 #ifdef HAVE_MONOTONIC_CLOCK
230  if (have_monotonic_clock)
231  {
232  struct timespec monotonic_timer;
233  clock_gettime (CLOCK_MONOTONIC,&monotonic_timer);
234  time_now.tv_sec = monotonic_timer.tv_sec;
235  time_now.tv_usec = monotonic_timer.tv_nsec / 1000;
236  }
237  else
238  /* This else falls through to gettimeofday */
239 #endif
240  gettimeofday (&time_now, NULL);
241 
242  end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
243  end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
244  if (end_time.tv_nsec > 1000*1000*1000)
245  {
246  end_time.tv_sec += 1;
247  end_time.tv_nsec -= 1000*1000*1000;
248  }
249 
250  result = pthread_cond_timedwait (&cond->cond, &mutex->lock, &end_time);
251 
252  if (result != ETIMEDOUT)
253  {
254  PTHREAD_CHECK ("pthread_cond_timedwait", result);
255  }
256 
257  /* return true if we did not time out */
258  return result != ETIMEDOUT;
259 }
260 
261 void
262 _dbus_platform_condvar_wake_one (DBusCondVar *cond)
263 {
264  PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&cond->cond));
265 }
266 
267 static void
268 check_monotonic_clock (void)
269 {
270 #ifdef HAVE_MONOTONIC_CLOCK
271  struct timespec dummy;
272  if (clock_getres (CLOCK_MONOTONIC, &dummy) == 0)
273  have_monotonic_clock = TRUE;
274 #endif
275 }
276 
279 {
280  /* These have static variables, and we need to handle both the case
281  * where dbus_threads_init() has been called and when it hasn't;
282  * so initialize them before any threads are allowed to enter.
283  */
284  check_monotonic_clock ();
285  (void) _dbus_check_setuid ();
286 
287  return TRUE;
288 }
289 
290 static pthread_mutex_t init_mutex = PTHREAD_MUTEX_INITIALIZER;
291 
292 void
294 {
295  pthread_mutex_lock (&init_mutex);
296 }
297 
298 void
300 {
301  pthread_mutex_unlock (&init_mutex);
302 }
#define NULL
A null pointer, defined appropriately for C or C++.
void dbus_free(void *memory)
Frees a block of memory previously allocated by dbus_malloc() or dbus_malloc0().
Definition: dbus-memory.c:701
#define dbus_new(type, count)
Safe macro for using dbus_malloc().
Definition: dbus-memory.h:58
dbus_bool_t _dbus_check_setuid(void)
NOTE: If you modify this function, please also consider making the corresponding change in GLib...
dbus_bool_t _dbus_threads_init_platform_specific(void)
Initialize threads as in dbus_threads_init_default(), appropriately for the platform.
pthread_mutex_t lock
the lock
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().
dbus_uint32_t dbus_bool_t
A boolean, valid values are TRUE and FALSE.
Definition: dbus-types.h:35
#define TRUE
Expands to "1".
pthread_cond_t cond
the condition