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      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 }
    192