D-Bus 1.6.12

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 /* Whether we have a "monotonic" clock; i.e. a clock not affected by
00040  * changes in system time.
00041  * This is initialized once in check_monotonic_clock below.
00042  * https://bugs.freedesktop.org/show_bug.cgi?id=18121
00043  */
00044 static dbus_bool_t have_monotonic_clock = 0;
00045 
00046 struct DBusRMutex {
00047   pthread_mutex_t lock; 
00048 };
00049 
00050 struct DBusCMutex {
00051   pthread_mutex_t lock; 
00052 };
00053 
00054 struct DBusCondVar {
00055   pthread_cond_t cond; 
00056 };
00057 
00058 #define DBUS_MUTEX(m)         ((DBusMutex*) m)
00059 #define DBUS_MUTEX_PTHREAD(m) ((DBusMutexPThread*) m)
00060 
00061 #define DBUS_COND_VAR(c)         ((DBusCondVar*) c)
00062 #define DBUS_COND_VAR_PTHREAD(c) ((DBusCondVarPThread*) c)
00063 
00064 
00065 #ifdef DBUS_DISABLE_ASSERT
00066 /* (tmp != 0) is a no-op usage to silence compiler */
00067 #define PTHREAD_CHECK(func_name, result_or_call)    \
00068     do { int tmp = (result_or_call); if (tmp != 0) {;} } while (0)
00069 #else
00070 #define PTHREAD_CHECK(func_name, result_or_call) do {                                  \
00071     int tmp = (result_or_call);                                                        \
00072     if (tmp != 0) {                                                                    \
00073       _dbus_warn_check_failed ("pthread function %s failed with %d %s in %s\n",        \
00074                                func_name, tmp, strerror(tmp), _DBUS_FUNCTION_NAME);    \
00075     }                                                                                  \
00076 } while (0)
00077 #endif /* !DBUS_DISABLE_ASSERT */
00078 
00079 DBusCMutex *
00080 _dbus_platform_cmutex_new (void)
00081 {
00082   DBusCMutex *pmutex;
00083   int result;
00084 
00085   pmutex = dbus_new (DBusCMutex, 1);
00086   if (pmutex == NULL)
00087     return NULL;
00088 
00089   result = pthread_mutex_init (&pmutex->lock, NULL);
00090 
00091   if (result == ENOMEM || result == EAGAIN)
00092     {
00093       dbus_free (pmutex);
00094       return NULL;
00095     }
00096   else
00097     {
00098       PTHREAD_CHECK ("pthread_mutex_init", result);
00099     }
00100 
00101   return pmutex;
00102 }
00103 
00104 DBusRMutex *
00105 _dbus_platform_rmutex_new (void)
00106 {
00107   DBusRMutex *pmutex;
00108   pthread_mutexattr_t mutexattr;
00109   int result;
00110 
00111   pmutex = dbus_new (DBusRMutex, 1);
00112   if (pmutex == NULL)
00113     return NULL;
00114 
00115   pthread_mutexattr_init (&mutexattr);
00116   pthread_mutexattr_settype (&mutexattr, PTHREAD_MUTEX_RECURSIVE);
00117   result = pthread_mutex_init (&pmutex->lock, &mutexattr);
00118   pthread_mutexattr_destroy (&mutexattr);
00119 
00120   if (result == ENOMEM || result == EAGAIN)
00121     {
00122       dbus_free (pmutex);
00123       return NULL;
00124     }
00125   else
00126     {
00127       PTHREAD_CHECK ("pthread_mutex_init", result);
00128     }
00129 
00130   return pmutex;
00131 }
00132 
00133 void
00134 _dbus_platform_cmutex_free (DBusCMutex *mutex)
00135 {
00136   PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
00137   dbus_free (mutex);
00138 }
00139 
00140 void
00141 _dbus_platform_rmutex_free (DBusRMutex *mutex)
00142 {
00143   PTHREAD_CHECK ("pthread_mutex_destroy", pthread_mutex_destroy (&mutex->lock));
00144   dbus_free (mutex);
00145 }
00146 
00147 void
00148 _dbus_platform_cmutex_lock (DBusCMutex *mutex)
00149 {
00150   PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
00151 }
00152 
00153 void
00154 _dbus_platform_rmutex_lock (DBusRMutex *mutex)
00155 {
00156   PTHREAD_CHECK ("pthread_mutex_lock", pthread_mutex_lock (&mutex->lock));
00157 }
00158 
00159 void
00160 _dbus_platform_cmutex_unlock (DBusCMutex *mutex)
00161 {
00162   PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
00163 }
00164 
00165 void
00166 _dbus_platform_rmutex_unlock (DBusRMutex *mutex)
00167 {
00168   PTHREAD_CHECK ("pthread_mutex_unlock", pthread_mutex_unlock (&mutex->lock));
00169 }
00170 
00171 DBusCondVar *
00172 _dbus_platform_condvar_new (void)
00173 {
00174   DBusCondVar *pcond;
00175   pthread_condattr_t attr;
00176   int result;
00177   
00178   pcond = dbus_new (DBusCondVar, 1);
00179   if (pcond == NULL)
00180     return NULL;
00181 
00182   pthread_condattr_init (&attr);
00183 #ifdef HAVE_MONOTONIC_CLOCK
00184   if (have_monotonic_clock)
00185     pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
00186 #endif
00187 
00188   result = pthread_cond_init (&pcond->cond, &attr);
00189   pthread_condattr_destroy (&attr);
00190 
00191   if (result == EAGAIN || result == ENOMEM)
00192     {
00193       dbus_free (pcond);
00194       return NULL;
00195     }
00196   else
00197     {
00198       PTHREAD_CHECK ("pthread_cond_init", result);
00199     }
00200   
00201   return pcond;
00202 }
00203 
00204 void
00205 _dbus_platform_condvar_free (DBusCondVar *cond)
00206 {
00207   PTHREAD_CHECK ("pthread_cond_destroy", pthread_cond_destroy (&cond->cond));
00208   dbus_free (cond);
00209 }
00210 
00211 void
00212 _dbus_platform_condvar_wait (DBusCondVar *cond,
00213                              DBusCMutex  *mutex)
00214 {
00215   PTHREAD_CHECK ("pthread_cond_wait", pthread_cond_wait (&cond->cond, &mutex->lock));
00216 }
00217 
00218 dbus_bool_t
00219 _dbus_platform_condvar_wait_timeout (DBusCondVar               *cond,
00220                                      DBusCMutex                *mutex,
00221                                      int                        timeout_milliseconds)
00222 {
00223   struct timeval time_now;
00224   struct timespec end_time;
00225   int result;
00226 
00227 #ifdef HAVE_MONOTONIC_CLOCK
00228   if (have_monotonic_clock)
00229     {
00230       struct timespec monotonic_timer;
00231       clock_gettime (CLOCK_MONOTONIC,&monotonic_timer);
00232       time_now.tv_sec = monotonic_timer.tv_sec;
00233       time_now.tv_usec = monotonic_timer.tv_nsec / 1000;
00234     }
00235   else
00236     /* This else falls through to gettimeofday */
00237 #endif
00238   gettimeofday (&time_now, NULL);
00239   
00240   end_time.tv_sec = time_now.tv_sec + timeout_milliseconds / 1000;
00241   end_time.tv_nsec = (time_now.tv_usec + (timeout_milliseconds % 1000) * 1000) * 1000;
00242   if (end_time.tv_nsec > 1000*1000*1000)
00243     {
00244       end_time.tv_sec += 1;
00245       end_time.tv_nsec -= 1000*1000*1000;
00246     }
00247 
00248   result = pthread_cond_timedwait (&cond->cond, &mutex->lock, &end_time);
00249   
00250   if (result != ETIMEDOUT)
00251     {
00252       PTHREAD_CHECK ("pthread_cond_timedwait", result);
00253     }
00254 
00255   /* return true if we did not time out */
00256   return result != ETIMEDOUT;
00257 }
00258 
00259 void
00260 _dbus_platform_condvar_wake_one (DBusCondVar *cond)
00261 {
00262   PTHREAD_CHECK ("pthread_cond_signal", pthread_cond_signal (&cond->cond));
00263 }
00264 
00265 static void
00266 check_monotonic_clock (void)
00267 {
00268 #ifdef HAVE_MONOTONIC_CLOCK
00269   struct timespec dummy;
00270   if (clock_getres (CLOCK_MONOTONIC, &dummy) == 0)
00271     have_monotonic_clock = TRUE;
00272 #endif
00273 }
00274 
00275 dbus_bool_t
00276 _dbus_threads_init_platform_specific (void)
00277 {
00278   /* These have static variables, and we need to handle both the case
00279    * where dbus_threads_init() has been called and when it hasn't;
00280    * so initialize them before any threads are allowed to enter.
00281    */
00282   check_monotonic_clock ();
00283   (void) _dbus_check_setuid ();
00284   return dbus_threads_init (NULL);
00285 }