contrib/ntp/sntp/libevent/evthread_pthread.c

   1 /*
   2  * Copyright 2009-2012 Niels Provos and Nick Mathewson
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. The name of the author may not be used to endorse or promote products
  13  *    derived from this software without specific prior written permission.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26 #include "event2/event-config.h"
  27 #include "evconfig-private.h"
  28
  29 /* With glibc we need to define _GNU_SOURCE to get PTHREAD_MUTEX_RECURSIVE.
  30  * This comes from evconfig-private.h
  31  */
  32 #include <pthread.h>
  33
  34 struct event_base;
  35 #include "event2/thread.h"
  36
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include "mm-internal.h"
  40 #include "evthread-internal.h"
  41
  42 static pthread_mutexattr_t attr_recursive;
  43
  44 static void *
  45 evthread_posix_lock_alloc(unsigned locktype)
  46 {
  47         pthread_mutexattr_t *attr = NULL;
  48         pthread_mutex_t *lock = mm_malloc(sizeof(pthread_mutex_t));
  49         if (!lock)
  50                 return NULL;
  51         if (locktype & EVTHREAD_LOCKTYPE_RECURSIVE)
  52                 attr = &attr_recursive;
  53         if (pthread_mutex_init(lock, attr)) {
  54                 mm_free(lock);
  55                 return NULL;
  56         }
  57         return lock;
  58 }
  59
  60 static void
  61 evthread_posix_lock_free(void *lock_, unsigned locktype)
  62 {
  63         pthread_mutex_t *lock = lock_;
  64         pthread_mutex_destroy(lock);
  65         mm_free(lock);
  66 }
  67
  68 static int
  69 evthread_posix_lock(unsigned mode, void *lock_)
  70 {
  71         pthread_mutex_t *lock = lock_;
  72         if (mode & EVTHREAD_TRY)
  73                 return pthread_mutex_trylock(lock);
  74         else
  75                 return pthread_mutex_lock(lock);
  76 }
  77
  78 static int
  79 evthread_posix_unlock(unsigned mode, void *lock_)
  80 {
  81         pthread_mutex_t *lock = lock_;
  82         return pthread_mutex_unlock(lock);
  83 }
  84
  85 static unsigned long
  86 evthread_posix_get_id(void)
  87 {
  88         union {
  89                 pthread_t thr;
  90 #if EVENT__SIZEOF_PTHREAD_T > EVENT__SIZEOF_LONG
  91                 ev_uint64_t id;
  92 #else
  93                 unsigned long id;
  94 #endif
  95         } r;
  96 #if EVENT__SIZEOF_PTHREAD_T < EVENT__SIZEOF_LONG
  97         memset(&r, 0, sizeof(r));
  98 #endif
  99         r.thr = pthread_self();
 100         return (unsigned long)r.id;
 101 }
 102
 103 static void *
 104 evthread_posix_cond_alloc(unsigned condflags)
 105 {
 106         pthread_cond_t *cond = mm_malloc(sizeof(pthread_cond_t));
 107         if (!cond)
 108                 return NULL;
 109         if (pthread_cond_init(cond, NULL)) {
 110                 mm_free(cond);
 111                 return NULL;
 112         }
 113         return cond;
 114 }
 115
 116 static void
 117 evthread_posix_cond_free(void *cond_)
 118 {
 119         pthread_cond_t *cond = cond_;
 120         pthread_cond_destroy(cond);
 121         mm_free(cond);
 122 }
 123
 124 static int
 125 evthread_posix_cond_signal(void *cond_, int broadcast)
 126 {
 127         pthread_cond_t *cond = cond_;
 128         int r;
 129         if (broadcast)
 130                 r = pthread_cond_broadcast(cond);
 131         else
 132                 r = pthread_cond_signal(cond);
 133         return r ? -1 : 0;
 134 }
 135
 136 static int
 137 evthread_posix_cond_wait(void *cond_, void *lock_, const struct timeval *tv)
 138 {
 139         int r;
 140         pthread_cond_t *cond = cond_;
 141         pthread_mutex_t *lock = lock_;
 142
 143         if (tv) {
 144                 struct timeval now, abstime;
 145                 struct timespec ts;
 146                 evutil_gettimeofday(&now, NULL);
 147                 evutil_timeradd(&now, tv, &abstime);
 148                 ts.tv_sec = abstime.tv_sec;
 149                 ts.tv_nsec = abstime.tv_usec*1000;
 150                 r = pthread_cond_timedwait(cond, lock, &ts);
 151                 if (r == ETIMEDOUT)
 152                         return 1;
 153                 else if (r)
 154                         return -1;
 155                 else
 156                         return 0;
 157         } else {
 158                 r = pthread_cond_wait(cond, lock);
 159                 return r ? -1 : 0;
 160         }
 161 }
 162
 163 int
 164 evthread_use_pthreads(void)
 165 {
 166         struct evthread_lock_callbacks cbs = {
 167                 EVTHREAD_LOCK_API_VERSION,
 168                 EVTHREAD_LOCKTYPE_RECURSIVE,
 169                 evthread_posix_lock_alloc,
 170                 evthread_posix_lock_free,
 171                 evthread_posix_lock,
 172                 evthread_posix_unlock
 173         };
 174         struct evthread_condition_callbacks cond_cbs = {
 175                 EVTHREAD_CONDITION_API_VERSION,
 176                 evthread_posix_cond_alloc,
 177                 evthread_posix_cond_free,
 178                 evthread_posix_cond_signal,
 179                 evthread_posix_cond_wait
 180         };
 181         /* Set ourselves up to get recursive locks. */
 182         if (pthread_mutexattr_init(&attr_recursive))
 183                 return -1;
 184         if (pthread_mutexattr_settype(&attr_recursive, PTHREAD_MUTEX_RECURSIVE))
 185                 return -1;
 186
 187         evthread_set_lock_callbacks(&cbs);
 188         evthread_set_condition_callbacks(&cond_cbs);
 189         evthread_set_id_callback(evthread_posix_get_id);
 190         return 0;
 191 }