1/*	$NetBSD: sem.c,v 1.4 2008/04/28 20:23:02 martin Exp $	*/
2
3/*-
4 * Copyright (c) 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
34 * All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 *    notice(s), this list of conditions and the following disclaimer as
41 *    the first lines of this file unmodified other than the possible
42 *    addition of one or more copyright notices.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 *    notice(s), this list of conditions and the following disclaimer in
45 *    the documentation and/or other materials provided with the
46 *    distribution.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
49 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
51 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
52 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
53 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
54 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
55 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
56 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
57 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
58 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
59 */
60
61#include <sys/cdefs.h>
62__RCSID("$NetBSD: sem.c,v 1.4 2008/04/28 20:23:02 martin Exp $");
63
64/*
65 * If an application is linked against both librt and libpthread, the
66 * libpthread versions must be used.  Provide weak aliases to cause
67 * this behavior.
68 */
69#define	sem_init	_librt_sem_init
70#define	sem_destroy	_librt_sem_destroy
71#define	sem_open	_librt_sem_open
72#define	sem_close	_librt_sem_close
73#define	sem_unlink	_librt_sem_unlink
74#define	sem_wait	_librt_sem_wait
75#define	sem_trywait	_librt_sem_trywait
76#define	sem_post	_librt_sem_post
77#define	sem_getvalue	_librt_sem_getvalue
78
79#define	_LIBC
80
81#include <sys/types.h>
82#include <sys/ksem.h>
83#include <sys/queue.h>
84#include <stdlib.h>
85#include <errno.h>
86#include <fcntl.h>
87#include <semaphore.h>
88#include <stdarg.h>
89
90struct _sem_st {
91	unsigned int	ksem_magic;
92#define	KSEM_MAGIC	0x90af0421U
93
94	LIST_ENTRY(_sem_st) ksem_list;
95	intptr_t		ksem_semid;	/* 0 -> user (non-shared) */
96	sem_t		*ksem_identity;
97};
98
99static int sem_alloc(unsigned int value, intptr_t semid, sem_t *semp);
100static void sem_free(sem_t sem);
101
102static LIST_HEAD(, _sem_st) named_sems = LIST_HEAD_INITIALIZER(&named_sems);
103
104#ifdef __weak_alias
105__weak_alias(sem_init,_librt_sem_init)
106__weak_alias(sem_destroy,_librt_sem_destroy)
107__weak_alias(sem_open,_librt_sem_open)
108__weak_alias(sem_close,_librt_sem_close)
109__weak_alias(sem_unlink,_librt_sem_unlink)
110__weak_alias(sem_wait,_librt_sem_wait)
111__weak_alias(sem_trywait,_librt_sem_trywait)
112__weak_alias(sem_post,_librt_sem_post)
113__weak_alias(sem_getvalue,_librt_sem_getvalue)
114#endif
115
116static void
117sem_free(sem_t sem)
118{
119
120	sem->ksem_magic = 0;
121	free(sem);
122}
123
124static int
125sem_alloc(unsigned int value, intptr_t semid, sem_t *semp)
126{
127	sem_t sem;
128
129	if (value > SEM_VALUE_MAX)
130		return (EINVAL);
131
132	if ((sem = malloc(sizeof(struct _sem_st))) == NULL)
133		return (ENOSPC);
134
135	sem->ksem_magic = KSEM_MAGIC;
136	sem->ksem_semid = semid;
137
138	*semp = sem;
139	return (0);
140}
141
142/* ARGSUSED */
143int
144sem_init(sem_t *sem, int pshared, unsigned int value)
145{
146	intptr_t	semid;
147	int error;
148
149	if (_ksem_init(value, &semid) == -1)
150		return (-1);
151
152	if ((error = sem_alloc(value, semid, sem)) != 0) {
153		_ksem_destroy(semid);
154		errno = error;
155		return (-1);
156	}
157
158	return (0);
159}
160
161int
162sem_destroy(sem_t *sem)
163{
164
165#ifdef ERRORCHECK
166	if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
167		errno = EINVAL;
168		return (-1);
169	}
170#endif
171
172	if (_ksem_destroy((*sem)->ksem_semid) == -1)
173		return (-1);
174
175	sem_free(*sem);
176
177	return (0);
178}
179
180sem_t *
181sem_open(const char *name, int oflag, ...)
182{
183	sem_t *sem, s;
184	intptr_t semid;
185	mode_t mode;
186	unsigned int value;
187	int error;
188	va_list ap;
189
190	mode = 0;
191	value = 0;
192
193	if (oflag & O_CREAT) {
194		va_start(ap, oflag);
195		mode = va_arg(ap, int);
196		value = va_arg(ap, unsigned int);
197		va_end(ap);
198	}
199
200	/*
201	 * We can be lazy and let the kernel handle the oflag,
202	 * we'll just merge duplicate IDs into our list.
203	 */
204	if (_ksem_open(name, oflag, mode, value, &semid) == -1)
205		return (SEM_FAILED);
206
207	/*
208	 * Search for a duplicate ID, we must return the same sem_t *
209	 * if we locate one.
210	 */
211	LIST_FOREACH(s, &named_sems, ksem_list) {
212		if (s->ksem_semid == semid)
213			return (s->ksem_identity);
214	}
215
216	if ((sem = malloc(sizeof(*sem))) == NULL) {
217		error = ENOSPC;
218		goto bad;
219	}
220	if ((error = sem_alloc(value, semid, sem)) != 0)
221		goto bad;
222
223	LIST_INSERT_HEAD(&named_sems, *sem, ksem_list);
224	(*sem)->ksem_identity = sem;
225
226	return (sem);
227
228 bad:
229	_ksem_close(semid);
230	if (sem != NULL) {
231		if (*sem != NULL)
232			sem_free(*sem);
233		free(sem);
234	}
235	errno = error;
236	return (SEM_FAILED);
237}
238
239int
240sem_close(sem_t *sem)
241{
242
243#ifdef ERRORCHECK
244	if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
245		errno = EINVAL;
246		return (-1);
247	}
248#endif
249
250	if (_ksem_close((*sem)->ksem_semid) == -1)
251		return (-1);
252
253	LIST_REMOVE((*sem), ksem_list);
254	sem_free(*sem);
255	free(sem);
256	return (0);
257}
258
259int
260sem_unlink(const char *name)
261{
262
263	return (_ksem_unlink(name));
264}
265
266int
267sem_wait(sem_t *sem)
268{
269
270#ifdef ERRORCHECK
271	if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
272		errno = EINVAL;
273		return (-1);
274	}
275#endif
276
277	return (_ksem_wait((*sem)->ksem_semid));
278}
279
280int
281sem_trywait(sem_t *sem)
282{
283
284#ifdef ERRORCHECK
285	if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
286		errno = EINVAL;
287		return (-1);
288	}
289#endif
290
291	return (_ksem_trywait((*sem)->ksem_semid));
292}
293
294int
295sem_post(sem_t *sem)
296{
297
298#ifdef ERRORCHECK
299	if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
300		errno = EINVAL;
301		return (-1);
302	}
303#endif
304
305	return (_ksem_post((*sem)->ksem_semid));
306}
307
308int
309sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
310{
311
312#ifdef ERRORCHECK
313	if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
314		errno = EINVAL;
315		return (-1);
316	}
317#endif
318	return (_ksem_getvalue((*sem)->ksem_semid, sval));
319}
320