D-Bus  1.10.12
dbus-sysdeps-pthread.c
00001 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
00002 /* dbus-sysdeps-pthread.c Implements threads using pthreads (internal to libdbus)
00003  * 
00004  * Copyright (C) 2002, 2003, 2006  Red Hat, Inc.
00005  *
00006  * Licensed under the Academic Free License version 2.1
00007  * 
00008  * This program is free software; you can redistribute it and/or modify
00009  * it under the terms of the GNU General Public License as published by
00010  * the Free Software Foundation; either version 2 of the License, or
00011  * (at your option) any later version.
00012  *
00013  * This program is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016  * GNU General Public License for more details.
00017  * 
00018  * You should have received a copy of the GNU General Public License
00019  * along with this program; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
00021  *
00022  */
00023 
00024 #include <config.h>
00025 #include "dbus-internals.h"
00026 #include "dbus-sysdeps.h"
00027 #include "dbus-threads.h"
00028 
00029 #include <sys/time.h>
00030 #include <pthread.h>
00031 #include <string.h>
00032 
00033 #ifdef HAVE_ERRNO_H
00034 #include <errno.h>
00035 #endif
00036 
00037 #include <config.h>
00038 
00039 #ifdef HAVE_MONOTONIC_CLOCK
00040 /* Whether we have a "monotonic" clock; i.e. a clock not affected by
00041  * changes in system time.
00042  * This is initialized once in check_monotonic_clock below.
00043  * https://bugs.freedesktop.org/show_bug.cgi?id=18121
00044  */
00045 static dbus_bool_t have_monotonic_clock = 0;
00046 #endif
00047 
00048 struct DBusRMutex {
00049   pthread_mutex_t lock; 
00050 };
00051 
00052 struct DBusCMutex {
00053   pthread_mutex_t lock; 
00054 };
00055 
00056 struct DBusCondVar {
00057   pthread_cond_t cond; 
00058 };
00059 
00060 #define DBUS_MUTEX(m)         ((DBusMutex*) m)
00061 #define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
00062 
00063 #define DBUS_COND_VAR(c)         ((DBusCondVar*) c)
00064 #define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
00065 
00066 
00067 #ifdef DBUS_DISABLE_ASSERT
00068 /* (tmp != 0) is a no-op usage to silence compiler */
00069 #define PTHREAD_CHECK(func_name, result_or_call)    \
00070     do { int tmp = (result_or_call); if (tmp != 0) {;} } while (0)
00071 #else
00072 #define PTHREAD_CHECK(func_name, result_or_call) do {                                  \
00073     int tmp = (result_or_call);                                                        \
00074     if (tmp != 0) {                                                                    \
00075       _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s\n",        \
00076                                func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME);    \
00077     }                                                                                  \
00078 } while (0)
00079 #endif /* !DBUS_DISABLE_ASSERT */
00080 
00081 DBusCMutex *
00082 _dbus_platform_cmutex_new (void)
00083 {
00084   DBusCMutex *pmutex;
00085   int result;
00086 
00087   pmutex = dbus_new (DBusCMutex, 1);
00088   if (pmutex == NULL)
00089     return NULL;
00090 
00091   result = pthread_mutex_init (&pmutex->lock, NULL);
00092 
00093   if (result == ENOMEM || result == EAGAIN)
00094     {
00095       dbus_free (pmutex);
00096       return NULL;
00097     }
00098   else
00099     {
00100       PTHREAD_CHECK ("pthread_mutex_init", result);
00101     }
00102 
00103   return pmutex;
00104 }
00105 
00106 DBusRMutex *
00107 _dbus_platform_rmutex_new (void)
00108 {
00109   DBusRMutex *pmutex;
00110   pthread_mutexattr_t mutexattr;
00111   int result;
00112 
00113   pmutex = dbus_new (DBusRMutex, 1);
00114   if (pmutex == NULL)
00115     return NULL;
00116 
00117   pthread_mutexattr_init (&mutexattr);
00118   pthread_mutexattr_settype (&mutexattr, PTHREAD_MUTEX_RECURSIVE);
00119   result = pthread_mutex_init (&pmutex->lock, &mutexattr);
00120   pthread_mutexattr_destroy (&mutexattr);
00121 
00122   if (result == ENOMEM || result == EAGAIN)
00123     {
00124       dbus_free (pmutex);
00125       return NULL;
00126     }
00127   else
00128     {
00129       PTHREAD_CHECK ("pthread_mutex_init", result);
00130     }
00131 
00132   return pmutex;
00133 }
00134 
00135 void
00136 _dbus_platform_cmutex_free (DBusCMutex *mutex)
00137 {
00138   PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
00139   dbus_free (mutex);
00140 }
00141 
00142 void
00143 _dbus_platform_rmutex_free (DBusRMutex *mutex)
00144 {
00145   PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
00146   dbus_free (mutex);
00147 }
00148 
00149 void
00150 _dbus_platform_cmutex_lock (DBusCMutex *mutex)
00151 {
00152   PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
00153 }
00154 
00155 void
00156 _dbus_platform_rmutex_lock (DBusRMutex *mutex)
00157 {
00158   PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
00159 }
00160 
00161 void
00162 _dbus_platform_cmutex_unlock (DBusCMutex *mutex)
00163 {
00164   PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
00165 }
00166 
00167 void
00168 _dbus_platform_rmutex_unlock (DBusRMutex *mutex)
00169 {
00170   PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
00171 }
00172 
00173 DBusCondVar *
00174 _dbus_platform_condvar_new (void)
00175 {
00176   DBusCondVar *pcond;
00177   pthread_condattr_t attr;
00178   int result;
00179   
00180   pcond = dbus_new (DBusCondVar, 1);
00181   if (pcond == NULL)
00182     return NULL;
00183 
00184   pthread_condattr_init (&attr);
00185 #ifdef HAVE_MONOTONIC_CLOCK
00186   if (have_monotonic_clock)
00187     pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
00188 #endif
00189 
00190   result = pthread_cond_init (&pcond->cond, &attr);
00191   pthread_condattr_destroy (&attr);
00192 
00193   if (result == EAGAIN || result == ENOMEM)
00194     {
00195       dbus_free (pcond);
00196       return NULL;
00197     }
00198   else
00199     {
00200       PTHREAD_CHECK ("pthread_cond_init", result);
00201     }
00202   
00203   return pcond;
00204 }
00205 
00206 void
00207 _dbus_platform_condvar_free (DBusCondVar *cond)
00208 {
00209   PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&cond->cond));
00210   dbus_free (cond);
00211 }
00212 
00213 void
00214 _dbus_platform_condvar_wait (DBusCondVar *cond,
00215                              DBusCMutex  *mutex)
00216 {
00217   PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&cond->cond, &mutex->lock));
00218 }
00219 
00220 dbus_bool_t
00221 _dbus_platform_condvar_wait_timeout (DBusCondVar               *cond,
00222                                      DBusCMutex                *mutex,
00223                                      int                        timeout_milliseconds)
00224 {
00225   struct timeval time_now;
00226   struct timespec end_time;
00227   int result;
00228 
00229 #ifdef HAVE_MONOTONIC_CLOCK
00230   if (have_monotonic_clock)
00231     {
00232       struct timespec monotonic_timer;
00233       clock_gettime (CLOCK_MONOTONIC,&monotonic_timer);
00234       time_now.tv_sec = monotonic_timer.tv_sec;
00235       time_now.tv_usec = monotonic_timer.tv_nsec / 1000;
00236     }
00237   else
00238     /* This else falls through to gettimeofday */
00239 #endif
00240   gettimeofday (&time_now, NULL);
00241   
00242   end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
00243   end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
00244   if (end_time.tv_nsec > 1000*1000*1000)
00245     {
00246       end_time.tv_sec += 1;
00247       end_time.tv_nsec -= 1000*1000*1000;
00248     }
00249 
00250   result = pthread_cond_timedwait (&cond->cond, &mutex->lock, &end_time);
00251   
00252   if (result != ETIMEDOUT)
00253     {
00254       PTHREAD_CHECK ("pthread_cond_timedwait", result);
00255     }
00256 
00257   /* return true if we did not time out */
00258   return result != ETIMEDOUT;
00259 }
00260 
00261 void
00262 _dbus_platform_condvar_wake_one (DBusCondVar *cond)
00263 {
00264   PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&cond->cond));
00265 }
00266 
00267 static void
00268 check_monotonic_clock (void)
00269 {
00270 #ifdef HAVE_MONOTONIC_CLOCK
00271   struct timespec dummy;
00272   if (clock_getres (CLOCK_MONOTONIC, &dummy) == 0)
00273     have_monotonic_clock = TRUE;
00274 #endif
00275 }
00276 
00277 dbus_bool_t
00278 _dbus_threads_init_platform_specific (void)
00279 {
00280   /* These have static variables, and we need to handle both the case
00281    * where dbus_threads_init() has been called and when it hasn't;
00282    * so initialize them before any threads are allowed to enter.
00283    */
00284   check_monotonic_clock ();
00285   (void) _dbus_check_setuid ();
00286 
00287   return TRUE;
00288 }
00289 
00290 static pthread_mutex_t init_mutex = PTHREAD_MUTEX_INITIALIZER;
00291 
00292 void
00293 _dbus_threads_lock_platform_specific (void)
00294 {
00295   pthread_mutex_lock (&init_mutex);
00296 }
00297 
00298 void
00299 _dbus_threads_unlock_platform_specific (void)
00300 {
00301   pthread_mutex_unlock (&init_mutex);
00302 }