2 * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice(s), this list of conditions and the following disclaimer as
10 * the first lines of this file unmodified other than the possible
11 * addition of one or more copyright notices.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice(s), this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
21 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
24 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
26 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
27 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 * $FreeBSD: src/lib/libc_r/uthread/uthread_sem.c,v 1.3.2.5 2002/10/22 14:44:03 fjoe Exp $
30 * $DragonFly: src/lib/libc_r/uthread/uthread_sem.c,v 1.3 2005/05/30 20:50:53 joerg Exp $
35 #include <semaphore.h>
37 #include "pthread_private.h"
39 #define _SEM_CHECK_VALIDITY(sem) \
40 if ((*(sem))->magic != SEM_MAGIC) { \
47 _sem_init(sem_t *sem, int pshared, unsigned int value)
52 * Range check the arguments.
56 * The user wants a semaphore that can be shared among
57 * processes, which this implementation can't do. Sounds like a
58 * permissions problem to me (yeah right).
65 if (value > SEM_VALUE_MAX) {
71 *sem = (sem_t)malloc(sizeof(struct sem));
79 * Initialize the semaphore.
81 if (pthread_mutex_init(&(*sem)->lock, NULL) != 0) {
88 if (pthread_cond_init(&(*sem)->gtzero, NULL) != 0) {
89 pthread_mutex_destroy(&(*sem)->lock);
96 (*sem)->count = (u_int32_t)value;
98 (*sem)->magic = SEM_MAGIC;
106 _sem_destroy(sem_t *sem)
110 _SEM_CHECK_VALIDITY(sem);
112 /* Make sure there are no waiters. */
113 pthread_mutex_lock(&(*sem)->lock);
114 if ((*sem)->nwaiters > 0) {
115 pthread_mutex_unlock(&(*sem)->lock);
120 pthread_mutex_unlock(&(*sem)->lock);
122 pthread_mutex_destroy(&(*sem)->lock);
123 pthread_cond_destroy(&(*sem)->gtzero);
134 _sem_open(const char *name, int oflag, ...)
141 _sem_close(sem_t *sem)
148 _sem_unlink(const char *name)
155 _sem_wait(sem_t *sem)
159 _thread_enter_cancellation_point();
161 _SEM_CHECK_VALIDITY(sem);
163 pthread_mutex_lock(&(*sem)->lock);
165 while ((*sem)->count == 0) {
167 pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
172 pthread_mutex_unlock(&(*sem)->lock);
176 _thread_leave_cancellation_point();
181 _sem_trywait(sem_t *sem)
185 _SEM_CHECK_VALIDITY(sem);
187 pthread_mutex_lock(&(*sem)->lock);
189 if ((*sem)->count > 0) {
197 pthread_mutex_unlock(&(*sem)->lock);
204 _sem_post(sem_t *sem)
208 _SEM_CHECK_VALIDITY(sem);
211 * sem_post() is required to be safe to call from within signal
212 * handlers. Thus, we must defer signals.
214 _thread_kern_sig_defer();
216 pthread_mutex_lock(&(*sem)->lock);
219 if ((*sem)->nwaiters > 0)
220 pthread_cond_signal(&(*sem)->gtzero);
222 pthread_mutex_unlock(&(*sem)->lock);
224 _thread_kern_sig_undefer();
231 _sem_getvalue(sem_t *sem, int *sval)
235 _SEM_CHECK_VALIDITY(sem);
237 pthread_mutex_lock(&(*sem)->lock);
238 *sval = (int)(*sem)->count;
239 pthread_mutex_unlock(&(*sem)->lock);
246 __strong_reference(_sem_init, sem_init);
247 __strong_reference(_sem_destroy, sem_destroy);
248 __strong_reference(_sem_open, sem_open);
249 __strong_reference(_sem_close, sem_close);
250 __strong_reference(_sem_unlink, sem_unlink);
251 __strong_reference(_sem_wait, sem_wait);
252 __strong_reference(_sem_trywait, sem_trywait);
253 __strong_reference(_sem_post, sem_post);
254 __strong_reference(_sem_getvalue, sem_getvalue);