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 */
44static dbus_bool_t have_monotonic_clock = 0;
45
46struct DBusRMutex {
47  pthread_mutex_t lock; /**< the lock */
48};
49
50struct DBusCMutex {
51  pthread_mutex_t lock; /**< the lock */
52};
53
54struct 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
79DBusCMutex *
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
104DBusRMutex *
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
133void
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
140void
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
147void
148_dbus_platform_cmutex_lock (DBusCMutex *mutex)
149{
150  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
151}
152
153void
154_dbus_platform_rmutex_lock (DBusRMutex *mutex)
155{
156  PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
157}
158
159void
160_dbus_platform_cmutex_unlock (DBusCMutex *mutex)
161{
162  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
163}
164
165void
166_dbus_platform_rmutex_unlock (DBusRMutex *mutex)
167{
168  PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
169}
170
171DBusCondVar *
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
204void
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
211void
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
218dbus_bool_t
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
259void
260_dbus_platform_condvar_wake_one (DBusCondVar *cond)
261{
262  PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&cond->cond));
263}
264
265static void
266check_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
275dbus_bool_t
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