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