D-Bus  1.16.2
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  * 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 
26 #include <config.h>
27 #include "dbus-internals.h"
28 #include "dbus-sysdeps.h"
29 #include "dbus-threads.h"
30 
31 #include <sys/time.h>
32 #include <pthread.h>
33 #include <stdio.h>
34 #include <string.h>
35 
36 #ifdef HAVE_ERRNO_H
37 #include <errno.h>
38 #endif
39 
40 #include <config.h>
41 
42 #ifdef HAVE_MONOTONIC_CLOCK
43 /* Whether we have a "monotonic" clock; i.e. a clock not affected by
44  * changes in system time.
45  * This is initialized once in check_monotonic_clock below.
46  * https://bugs.freedesktop.org/show_bug.cgi?id=18121
47  */
48 static dbus_bool_t have_monotonic_clock = 0;
49 #endif
50 
51 struct DBusRMutex {
52  pthread_mutex_t lock;
53 };
54 
55 struct DBusCMutex {
56  pthread_mutex_t lock;
57 };
58 
59 struct DBusCondVar {
60  pthread_cond_t cond;
61 };
62 
63 #define DBUS_MUTEX(m) ((DBusMutex*) m)
64 #define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
65 
66 #define DBUS_COND_VAR(c) ((DBusCondVar*) c)
67 #define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
68 
69 
70 #ifdef DBUS_DISABLE_ASSERT
71 /* (tmp != 0) is a no-op usage to silence compiler */
72 #define PTHREAD_CHECK(func_name, result_or_call) \
73  do { int tmp = (result_or_call); if (tmp != 0) {;} } while (0)
74 #else
75 #define PTHREAD_CHECK(func_name, result_or_call) do { \
76  int tmp = (result_or_call); \
77  if (tmp != 0) { \
78  _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s", \
79  func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME); \
80  } \
81 } while (0)
82 #endif /* !DBUS_DISABLE_ASSERT */
83 
84 DBusCMutex *
85 _dbus_platform_cmutex_new (void)
86 {
87  DBusCMutex *pmutex;
88  int result;
89 
90  pmutex = dbus_new (DBusCMutex, 1);
91  if (pmutex == NULL)
92  return NULL;
93 
94  result = pthread_mutex_init (&pmutex->lock, NULL);
95 
96  if (result == ENOMEM || result == EAGAIN)
97  {
98  dbus_free (pmutex);
99  return NULL;
100  }
101  else
102  {
103  PTHREAD_CHECK ("pthread_mutex_init", result);
104  }
105 
106  return pmutex;
107 }
108 
109 DBusRMutex *
110 _dbus_platform_rmutex_new (void)
111 {
112  DBusRMutex *pmutex;
113  pthread_mutexattr_t mutexattr;
114  int result;
115 
116  pmutex = dbus_new (DBusRMutex, 1);
117  if (pmutex == NULL)
118  return NULL;
119 
120  pthread_mutexattr_init (&mutexattr);
121  pthread_mutexattr_settype (&mutexattr, PTHREAD_MUTEX_RECURSIVE);
122  result = pthread_mutex_init (&pmutex->lock, &mutexattr);
123  pthread_mutexattr_destroy (&mutexattr);
124 
125  if (result == ENOMEM || result == EAGAIN)
126  {
127  dbus_free (pmutex);
128  return NULL;
129  }
130  else
131  {
132  PTHREAD_CHECK ("pthread_mutex_init", result);
133  }
134 
135  return pmutex;
136 }
137 
138 void
139 _dbus_platform_cmutex_free (DBusCMutex *mutex)
140 {
141  PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
142  dbus_free (mutex);
143 }
144 
145 void
146 _dbus_platform_rmutex_free (DBusRMutex *mutex)
147 {
148  PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
149  dbus_free (mutex);
150 }
151 
152 void
153 _dbus_platform_cmutex_lock (DBusCMutex *mutex)
154 {
155  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
156 }
157 
158 void
159 _dbus_platform_rmutex_lock (DBusRMutex *mutex)
160 {
161  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
162 }
163 
164 void
165 _dbus_platform_cmutex_unlock (DBusCMutex *mutex)
166 {
167  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
168 }
169 
170 void
171 _dbus_platform_rmutex_unlock (DBusRMutex *mutex)
172 {
173  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
174 }
175 
176 DBusCondVar *
177 _dbus_platform_condvar_new (void)
178 {
179  DBusCondVar *pcond;
180  pthread_condattr_t attr;
181  int result;
182 
183  pcond = dbus_new (DBusCondVar, 1);
184  if (pcond == NULL)
185  return NULL;
186 
187  pthread_condattr_init (&attr);
188 #ifdef HAVE_MONOTONIC_CLOCK
189  if (have_monotonic_clock)
190  pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
191 #endif
192 
193  result = pthread_cond_init (&pcond->cond, &attr);
194  pthread_condattr_destroy (&attr);
195 
196  if (result == EAGAIN || result == ENOMEM)
197  {
198  dbus_free (pcond);
199  return NULL;
200  }
201  else
202  {
203  PTHREAD_CHECK ("pthread_cond_init", result);
204  }
205 
206  return pcond;
207 }
208 
209 void
210 _dbus_platform_condvar_free (DBusCondVar *cond)
211 {
212  PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&cond->cond));
213  dbus_free (cond);
214 }
215 
216 void
217 _dbus_platform_condvar_wait (DBusCondVar *cond,
218  DBusCMutex *mutex)
219 {
220  PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&cond->cond, &mutex->lock));
221 }
222 
224 _dbus_platform_condvar_wait_timeout (DBusCondVar *cond,
225  DBusCMutex *mutex,
226  int timeout_milliseconds)
227 {
228  struct timeval time_now;
229  struct timespec end_time;
230  int result;
231 
232 #ifdef HAVE_MONOTONIC_CLOCK
233  if (have_monotonic_clock)
234  {
235  struct timespec monotonic_timer;
236  clock_gettime (CLOCK_MONOTONIC,&monotonic_timer);
237  time_now.tv_sec = monotonic_timer.tv_sec;
238  time_now.tv_usec = monotonic_timer.tv_nsec / 1000;
239  }
240  else
241  /* This else falls through to gettimeofday */
242 #endif
243  gettimeofday (&time_now, NULL);
244 
245  end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
246  end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
247  if (end_time.tv_nsec > 1000*1000*1000)
248  {
249  end_time.tv_sec += 1;
250  end_time.tv_nsec -= 1000*1000*1000;
251  }
252 
253  result = pthread_cond_timedwait (&cond->cond, &mutex->lock, &end_time);
254 
255  if (result != ETIMEDOUT)
256  {
257  PTHREAD_CHECK ("pthread_cond_timedwait", result);
258  }
259 
260  /* return true if we did not time out */
261  return result != ETIMEDOUT;
262 }
263 
264 void
265 _dbus_platform_condvar_wake_one (DBusCondVar *cond)
266 {
267  PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&cond->cond));
268 }
269 
270 static void
271 check_monotonic_clock (void)
272 {
273 #ifdef HAVE_MONOTONIC_CLOCK
274  struct timespec dummy;
275  if (clock_getres (CLOCK_MONOTONIC, &dummy) == 0)
276  have_monotonic_clock = TRUE;
277 #endif
278 }
279 
282 {
283  /* These have static variables, and we need to handle both the case
284  * where dbus_threads_init() has been called and when it hasn't;
285  * so initialize them before any threads are allowed to enter.
286  */
287  check_monotonic_clock ();
288  (void) _dbus_check_setuid ();
289 
290  return TRUE;
291 }
292 
293 static pthread_mutex_t init_mutex = PTHREAD_MUTEX_INITIALIZER;
294 
295 void
297 {
298  pthread_mutex_lock (&init_mutex);
299 }
300 
301 void
303 {
304  pthread_mutex_unlock (&init_mutex);
305 }
306 
307 #ifdef DBUS_ENABLE_VERBOSE_MODE
308 /*
309  * If we can identify the current process and/or thread, print them to stderr followed by a colon.
310  */
311 void
312 _dbus_print_thread (void)
313 {
314 #ifdef __linux__
315  /* we know a pthread_t is numeric on Linux */
316  fprintf (stderr, "%lu: 0x%lx: ", _dbus_pid_for_log (), (unsigned long) pthread_self ());
317 #else
318  /* in principle pthread_t isn't required to be printable */
319  fprintf (stderr, "%lu: ", _dbus_pid_for_log ());
320 #endif
321 }
322 #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:710
#define dbus_new(type, count)
Safe macro for using dbus_malloc().
Definition: dbus-memory.h:59
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:37
#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