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 /* Whether we have a "monotonic" clock; i.e. a clock not affected by
40 * changes in system time.
41 * This is initialized once in check_monotonic_clock below.
42 * https://bugs.freedesktop.org/show_bug.cgi?id=18121
43 */
44 static dbus_bool_t have_monotonic_clock = 0;
45
46 struct DBusRMutex {
47 pthread_mutex_t lock; /**< the lock */
48 };
49
50 struct DBusCMutex {
51 pthread_mutex_t lock; /**< the lock */
52 };
53
54 struct DBusCondVar {
55 pthread_cond_t cond; /**< the condition */
56 };
57
58 #define DBUS_MUTEX(m) ((DBusMutex*) m)
59 #define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
60
61 #define DBUS_COND_VAR(c) ((DBusCondVar*) c)
62 #define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
63
64
65 #ifdef DBUS_DISABLE_ASSERT
66 /* (tmp != 0) is a no-op usage to silence compiler */
67 #define PTHREAD_CHECK(func_name, result_or_call) \
68 do { int tmp = (result_or_call); if (tmp != 0) {;} } while (0)
69 #else
70 #define PTHREAD_CHECK(func_name, result_or_call) do { \
71 int tmp = (result_or_call); \
72 if (tmp != 0) { \
73 _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s\n", \
74 func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME); \
75 } \
76 } while (0)
77 #endif /* !DBUS_DISABLE_ASSERT */
78
79 DBusCMutex *
_dbus_platform_cmutex_new(void)80 _dbus_platform_cmutex_new (void)
81 {
82 DBusCMutex *pmutex;
83 int result;
84
85 pmutex = dbus_new (DBusCMutex, 1);
86 if (pmutex == NULL)
87 return NULL;
88
89 result = pthread_mutex_init (&pmutex->lock, NULL);
90
91 if (result == ENOMEM || result == EAGAIN)
92 {
93 dbus_free (pmutex);
94 return NULL;
95 }
96 else
97 {
98 PTHREAD_CHECK ("pthread_mutex_init", result);
99 }
100
101 return pmutex;
102 }
103
104 DBusRMutex *
_dbus_platform_rmutex_new(void)105 _dbus_platform_rmutex_new (void)
106 {
107 DBusRMutex *pmutex;
108 pthread_mutexattr_t mutexattr;
109 int result;
110
111 pmutex = dbus_new (DBusRMutex, 1);
112 if (pmutex == NULL)
113 return NULL;
114
115 pthread_mutexattr_init (&mutexattr);
116 pthread_mutexattr_settype (&mutexattr, PTHREAD_MUTEX_RECURSIVE);
117 result = pthread_mutex_init (&pmutex->lock, &mutexattr);
118 pthread_mutexattr_destroy (&mutexattr);
119
120 if (result == ENOMEM || result == EAGAIN)
121 {
122 dbus_free (pmutex);
123 return NULL;
124 }
125 else
126 {
127 PTHREAD_CHECK ("pthread_mutex_init", result);
128 }
129
130 return pmutex;
131 }
132
133 void
_dbus_platform_cmutex_free(DBusCMutex * mutex)134 _dbus_platform_cmutex_free (DBusCMutex *mutex)
135 {
136 PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
137 dbus_free (mutex);
138 }
139
140 void
_dbus_platform_rmutex_free(DBusRMutex * mutex)141 _dbus_platform_rmutex_free (DBusRMutex *mutex)
142 {
143 PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
144 dbus_free (mutex);
145 }
146
147 void
_dbus_platform_cmutex_lock(DBusCMutex * mutex)148 _dbus_platform_cmutex_lock (DBusCMutex *mutex)
149 {
150 PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
151 }
152
153 void
_dbus_platform_rmutex_lock(DBusRMutex * mutex)154 _dbus_platform_rmutex_lock (DBusRMutex *mutex)
155 {
156 PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
157 }
158
159 void
_dbus_platform_cmutex_unlock(DBusCMutex * mutex)160 _dbus_platform_cmutex_unlock (DBusCMutex *mutex)
161 {
162 PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
163 }
164
165 void
_dbus_platform_rmutex_unlock(DBusRMutex * mutex)166 _dbus_platform_rmutex_unlock (DBusRMutex *mutex)
167 {
168 PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
169 }
170
171 DBusCondVar *
_dbus_platform_condvar_new(void)172 _dbus_platform_condvar_new (void)
173 {
174 DBusCondVar *pcond;
175 pthread_condattr_t attr;
176 int result;
177
178 pcond = dbus_new (DBusCondVar, 1);
179 if (pcond == NULL)
180 return NULL;
181
182 pthread_condattr_init (&attr);
183 #ifdef HAVE_MONOTONIC_CLOCK
184 if (have_monotonic_clock)
185 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
186 #endif
187
188 result = pthread_cond_init (&pcond->cond, &attr);
189 pthread_condattr_destroy (&attr);
190
191 if (result == EAGAIN || result == ENOMEM)
192 {
193 dbus_free (pcond);
194 return NULL;
195 }
196 else
197 {
198 PTHREAD_CHECK ("pthread_cond_init", result);
199 }
200
201 return pcond;
202 }
203
204 void
_dbus_platform_condvar_free(DBusCondVar * cond)205 _dbus_platform_condvar_free (DBusCondVar *cond)
206 {
207 PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&cond->cond));
208 dbus_free (cond);
209 }
210
211 void
_dbus_platform_condvar_wait(DBusCondVar * cond,DBusCMutex * mutex)212 _dbus_platform_condvar_wait (DBusCondVar *cond,
213 DBusCMutex *mutex)
214 {
215 PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&cond->cond, &mutex->lock));
216 }
217
218 dbus_bool_t
_dbus_platform_condvar_wait_timeout(DBusCondVar * cond,DBusCMutex * mutex,int timeout_milliseconds)219 _dbus_platform_condvar_wait_timeout (DBusCondVar *cond,
220 DBusCMutex *mutex,
221 int timeout_milliseconds)
222 {
223 struct timeval time_now;
224 struct timespec end_time;
225 int result;
226
227 #ifdef HAVE_MONOTONIC_CLOCK
228 if (have_monotonic_clock)
229 {
230 struct timespec monotonic_timer;
231 clock_gettime (CLOCK_MONOTONIC,&monotonic_timer);
232 time_now.tv_sec = monotonic_timer.tv_sec;
233 time_now.tv_usec = monotonic_timer.tv_nsec / 1000;
234 }
235 else
236 /* This else falls through to gettimeofday */
237 #endif
238 gettimeofday (&time_now, NULL);
239
240 end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
241 end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
242 if (end_time.tv_nsec > 1000*1000*1000)
243 {
244 end_time.tv_sec += 1;
245 end_time.tv_nsec -= 1000*1000*1000;
246 }
247
248 result = pthread_cond_timedwait (&cond->cond, &mutex->lock, &end_time);
249
250 if (result != ETIMEDOUT)
251 {
252 PTHREAD_CHECK ("pthread_cond_timedwait", result);
253 }
254
255 /* return true if we did not time out */
256 return result != ETIMEDOUT;
257 }
258
259 void
_dbus_platform_condvar_wake_one(DBusCondVar * cond)260 _dbus_platform_condvar_wake_one (DBusCondVar *cond)
261 {
262 PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&cond->cond));
263 }
264
265 static void
check_monotonic_clock(void)266 check_monotonic_clock (void)
267 {
268 #ifdef HAVE_MONOTONIC_CLOCK
269 struct timespec dummy;
270 if (clock_getres (CLOCK_MONOTONIC, &dummy) == 0)
271 have_monotonic_clock = TRUE;
272 #endif
273 }
274
275 dbus_bool_t
_dbus_threads_init_platform_specific(void)276 _dbus_threads_init_platform_specific (void)
277 {
278 /* These have static variables, and we need to handle both the case
279 * where dbus_threads_init() has been called and when it hasn't;
280 * so initialize them before any threads are allowed to enter.
281 */
282 check_monotonic_clock ();
283 (void) _dbus_check_setuid ();
284 return dbus_threads_init (NULL);
285 }
286