D-Bus  1.13.7
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 <stdio.h>
32 #include <string.h>
33 
34 #ifdef HAVE_ERRNO_H
35 #include <errno.h>
36 #endif
37 
38 #include <config.h>
39 
40 #ifdef HAVE_MONOTONIC_CLOCK
41 /* Whether we have a "monotonic" clock; i.e. a clock not affected by
42  * changes in system time.
43  * This is initialized once in check_monotonic_clock below.
44  * https://bugs.freedesktop.org/show_bug.cgi?id=18121
45  */
46 static dbus_bool_t have_monotonic_clock = 0;
47 #endif
48 
49 struct DBusRMutex {
50  pthread_mutex_t lock;
51 };
52 
53 struct DBusCMutex {
54  pthread_mutex_t lock;
55 };
56 
57 struct DBusCondVar {
58  pthread_cond_t cond;
59 };
60 
61 #define DBUS_MUTEX(m) ((DBusMutex*) m)
62 #define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
63 
64 #define DBUS_COND_VAR(c) ((DBusCondVar*) c)
65 #define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
66 
67 
68 #ifdef DBUS_DISABLE_ASSERT
69 /* (tmp != 0) is a no-op usage to silence compiler */
70 #define PTHREAD_CHECK(func_name, result_or_call) \
71  do { int tmp = (result_or_call); if (tmp != 0) {;} } while (0)
72 #else
73 #define PTHREAD_CHECK(func_name, result_or_call) do { \
74  int tmp = (result_or_call); \
75  if (tmp != 0) { \
76  _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s", \
77  func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME); \
78  } \
79 } while (0)
80 #endif /* !DBUS_DISABLE_ASSERT */
81 
82 DBusCMutex *
83 _dbus_platform_cmutex_new (void)
84 {
85  DBusCMutex *pmutex;
86  int result;
87 
88  pmutex = dbus_new (DBusCMutex, 1);
89  if (pmutex == NULL)
90  return NULL;
91 
92  result = pthread_mutex_init (&pmutex->lock, NULL);
93 
94  if (result == ENOMEM || result == EAGAIN)
95  {
96  dbus_free (pmutex);
97  return NULL;
98  }
99  else
100  {
101  PTHREAD_CHECK ("pthread_mutex_init", result);
102  }
103 
104  return pmutex;
105 }
106 
107 DBusRMutex *
108 _dbus_platform_rmutex_new (void)
109 {
110  DBusRMutex *pmutex;
111  pthread_mutexattr_t mutexattr;
112  int result;
113 
114  pmutex = dbus_new (DBusRMutex, 1);
115  if (pmutex == NULL)
116  return NULL;
117 
118  pthread_mutexattr_init (&mutexattr);
119  pthread_mutexattr_settype (&mutexattr, PTHREAD_MUTEX_RECURSIVE);
120  result = pthread_mutex_init (&pmutex->lock, &mutexattr);
121  pthread_mutexattr_destroy (&mutexattr);
122 
123  if (result == ENOMEM || result == EAGAIN)
124  {
125  dbus_free (pmutex);
126  return NULL;
127  }
128  else
129  {
130  PTHREAD_CHECK ("pthread_mutex_init", result);
131  }
132 
133  return pmutex;
134 }
135 
136 void
137 _dbus_platform_cmutex_free (DBusCMutex *mutex)
138 {
139  PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
140  dbus_free (mutex);
141 }
142 
143 void
144 _dbus_platform_rmutex_free (DBusRMutex *mutex)
145 {
146  PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
147  dbus_free (mutex);
148 }
149 
150 void
151 _dbus_platform_cmutex_lock (DBusCMutex *mutex)
152 {
153  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
154 }
155 
156 void
157 _dbus_platform_rmutex_lock (DBusRMutex *mutex)
158 {
159  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
160 }
161 
162 void
163 _dbus_platform_cmutex_unlock (DBusCMutex *mutex)
164 {
165  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
166 }
167 
168 void
169 _dbus_platform_rmutex_unlock (DBusRMutex *mutex)
170 {
171  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
172 }
173 
174 DBusCondVar *
175 _dbus_platform_condvar_new (void)
176 {
177  DBusCondVar *pcond;
178  pthread_condattr_t attr;
179  int result;
180 
181  pcond = dbus_new (DBusCondVar, 1);
182  if (pcond == NULL)
183  return NULL;
184 
185  pthread_condattr_init (&attr);
186 #ifdef HAVE_MONOTONIC_CLOCK
187  if (have_monotonic_clock)
188  pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
189 #endif
190 
191  result = pthread_cond_init (&pcond->cond, &attr);
192  pthread_condattr_destroy (&attr);
193 
194  if (result == EAGAIN || result == ENOMEM)
195  {
196  dbus_free (pcond);
197  return NULL;
198  }
199  else
200  {
201  PTHREAD_CHECK ("pthread_cond_init", result);
202  }
203 
204  return pcond;
205 }
206 
207 void
208 _dbus_platform_condvar_free (DBusCondVar *cond)
209 {
210  PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&cond->cond));
211  dbus_free (cond);
212 }
213 
214 void
215 _dbus_platform_condvar_wait (DBusCondVar *cond,
216  DBusCMutex *mutex)
217 {
218  PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&cond->cond, &mutex->lock));
219 }
220 
222 _dbus_platform_condvar_wait_timeout (DBusCondVar *cond,
223  DBusCMutex *mutex,
224  int timeout_milliseconds)
225 {
226  struct timeval time_now;
227  struct timespec end_time;
228  int result;
229 
230 #ifdef HAVE_MONOTONIC_CLOCK
231  if (have_monotonic_clock)
232  {
233  struct timespec monotonic_timer;
234  clock_gettime (CLOCK_MONOTONIC,&monotonic_timer);
235  time_now.tv_sec = monotonic_timer.tv_sec;
236  time_now.tv_usec = monotonic_timer.tv_nsec / 1000;
237  }
238  else
239  /* This else falls through to gettimeofday */
240 #endif
241  gettimeofday (&time_now, NULL);
242 
243  end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
244  end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
245  if (end_time.tv_nsec > 1000*1000*1000)
246  {
247  end_time.tv_sec += 1;
248  end_time.tv_nsec -= 1000*1000*1000;
249  }
250 
251  result = pthread_cond_timedwait (&cond->cond, &mutex->lock, &end_time);
252 
253  if (result != ETIMEDOUT)
254  {
255  PTHREAD_CHECK ("pthread_cond_timedwait", result);
256  }
257 
258  /* return true if we did not time out */
259  return result != ETIMEDOUT;
260 }
261 
262 void
263 _dbus_platform_condvar_wake_one (DBusCondVar *cond)
264 {
265  PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&cond->cond));
266 }
267 
268 static void
269 check_monotonic_clock (void)
270 {
271 #ifdef HAVE_MONOTONIC_CLOCK
272  struct timespec dummy;
273  if (clock_getres (CLOCK_MONOTONIC, &dummy) == 0)
274  have_monotonic_clock = TRUE;
275 #endif
276 }
277 
280 {
281  /* These have static variables, and we need to handle both the case
282  * where dbus_threads_init() has been called and when it hasn't;
283  * so initialize them before any threads are allowed to enter.
284  */
285  check_monotonic_clock ();
286  (void) _dbus_check_setuid ();
287 
288  return TRUE;
289 }
290 
291 static pthread_mutex_t init_mutex = PTHREAD_MUTEX_INITIALIZER;
292 
293 void
295 {
296  pthread_mutex_lock (&init_mutex);
297 }
298 
299 void
301 {
302  pthread_mutex_unlock (&init_mutex);
303 }
304 
305 #ifdef DBUS_ENABLE_VERBOSE_MODE
306 /*
307  * If we can identify the current process and/or thread, print them to stderr followed by a colon.
308  */
309 void
310 _dbus_print_thread (void)
311 {
312 #ifdef __linux__
313  /* we know a pthread_t is numeric on Linux */
314  fprintf (stderr, "%lu: 0x%lx: ", _dbus_pid_for_log (), (unsigned long) pthread_self ());
315 #else
316  /* in principle pthread_t isn't required to be printable */
317  fprintf (stderr, "%lu: ", _dbus_pid_for_log ());
318 #endif
319 }
320 #endif
#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:703
#define dbus_new(type, count)
Safe macro for using dbus_malloc().
Definition: dbus-memory.h:57
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".
unsigned long _dbus_pid_for_log(void)
The only reason this is separate from _dbus_getpid() is to allow it on Windows for logging but not fo...
pthread_cond_t cond
the condition