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*** empty log message ***
author Sam Lantinga <slouken@libsdl.org>
date Mon, 17 Dec 2001 19:56:28 +0000
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children 9631db4d9ee1
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255:dcb5e869f8b5 256:640dcf27d2f7
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id$";
26 #endif
27
28 #include <stdlib.h>
29 #include "SDL_error.h"
30 #include "SDL_thread.h"
31 #include "SDL_timer.h"
32
33 #ifdef SDL_USE_PTHREADS
34
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <unistd.h> /* For getpid() */
38 #include <pthread.h>
39
40
41 /*
42 * This is semaphore.h inlined here so that BSD/OS POSIX semaphore are
43 * completely selfcontained without requiring any additional include files
44 * or libraries not present in the stock system
45 */
46
47 /* semaphore.h: POSIX 1003.1b semaphores */
48
49 /*-
50 * Copyright (c) 1996, 1997
51 * HD Associates, Inc. All rights reserved.
52 *
53 * Redistribution and use in source and binary forms, with or without
54 * modification, are permitted provided that the following conditions
55 * are met:
56 * 1. Redistributions of source code must retain the above copyright
57 * notice, this list of conditions and the following disclaimer.
58 * 2. Redistributions in binary form must reproduce the above copyright
59 * notice, this list of conditions and the following disclaimer in the
60 * documentation and/or other materials provided with the distribution.
61 * 3. All advertising materials mentioning features or use of this software
62 * must display the following acknowledgement:
63 * This product includes software developed by HD Associates, Inc
64 * 4. Neither the name of the author nor the names of any co-contributors
65 * may be used to endorse or promote products derived from this software
66 * without specific prior written permission.
67 *
68 * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
69 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
70 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
71 * ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
72 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
73 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
74 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
75 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
76 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
77 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
78 * SUCH DAMAGE.
79 *
80 * $FreeBSD: src/sys/posix4/semaphore.h,v 1.6 2000/01/20 07:55:42 jasone Exp $
81 */
82
83 #include <machine/limits.h>
84
85 #include <sys/types.h>
86 #include <fcntl.h>
87
88 /* Opaque type definition. */
89 struct sem;
90 typedef struct sem *sem_t;
91
92 #define SEM_FAILED ((sem_t *)0)
93 #define SEM_VALUE_MAX UINT_MAX
94
95 #include <sys/cdefs.h>
96
97 __BEGIN_DECLS
98 int sem_init __P((sem_t *, int, unsigned int));
99 int sem_destroy __P((sem_t *));
100 sem_t *sem_open __P((const char *, int, ...));
101 int sem_close __P((sem_t *));
102 int sem_unlink __P((const char *));
103 int sem_wait __P((sem_t *));
104 int sem_trywait __P((sem_t *));
105 int sem_post __P((sem_t *));
106 int sem_getvalue __P((sem_t *, int *));
107 __END_DECLS
108
109 /* END of inlined semaphore.h */
110
111 /* Wrapper around POSIX 1003.1b semaphores */
112
113 struct SDL_semaphore {
114 sem_t *sem;
115 sem_t sem_data;
116 };
117
118 /* Create a semaphore, initialized with value */
119 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
120 {
121 SDL_sem *sem = (SDL_sem *) malloc(sizeof(SDL_sem));
122 if ( sem ) {
123 if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) {
124 SDL_SetError("sem_init() failed");
125 free(sem);
126 sem = NULL;
127 } else {
128 sem->sem = &sem->sem_data;
129 }
130 } else {
131 SDL_OutOfMemory();
132 }
133 return sem;
134 }
135
136 void SDL_DestroySemaphore(SDL_sem *sem)
137 {
138 if ( sem ) {
139 sem_destroy(sem->sem);
140 free(sem);
141 }
142 }
143
144 int SDL_SemTryWait(SDL_sem *sem)
145 {
146 int retval;
147
148 if ( ! sem ) {
149 SDL_SetError("Passed a NULL semaphore");
150 return -1;
151 }
152 retval = SDL_MUTEX_TIMEDOUT;
153 if ( sem_trywait(sem->sem) == 0 )
154 retval = 0;
155 return retval;
156 }
157
158 int SDL_SemWait(SDL_sem *sem)
159 {
160 int retval;
161
162 if ( ! sem ) {
163 SDL_SetError("Passed a NULL semaphore");
164 return -1;
165 }
166
167 retval = sem_wait(sem->sem);
168 if ( retval < 0 ) {
169 SDL_SetError("sem_wait() failed");
170 }
171 return retval;
172 }
173
174 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
175 {
176 int retval;
177
178 if ( ! sem ) {
179 SDL_SetError("Passed a NULL semaphore");
180 return -1;
181 }
182
183 /* Try the easy cases first */
184 if ( timeout == 0 ) {
185 return SDL_SemTryWait(sem);
186 }
187 if ( timeout == SDL_MUTEX_MAXWAIT ) {
188 return SDL_SemWait(sem);
189 }
190
191 /* Ack! We have to busy wait... */
192 timeout += SDL_GetTicks();
193 do {
194 retval = SDL_SemTryWait(sem);
195 if ( retval == 0 ) {
196 break;
197 }
198 SDL_Delay(1);
199 } while ( SDL_GetTicks() < timeout );
200
201 return retval;
202 }
203
204 Uint32 SDL_SemValue(SDL_sem *sem)
205 {
206 int ret = 0;
207 if ( sem ) {
208 sem_getvalue(sem->sem, &ret);
209 if ( ret < 0 ) {
210 ret = 0;
211 }
212 }
213 return (Uint32)ret;
214 }
215
216 int SDL_SemPost(SDL_sem *sem)
217 {
218 int retval;
219
220 if ( ! sem ) {
221 SDL_SetError("Passed a NULL semaphore");
222 return -1;
223 }
224
225 retval = sem_post(sem->sem);
226 if ( retval < 0 ) {
227 SDL_SetError("sem_post() failed");
228 }
229 return retval;
230 }
231
232 /*
233 * BEGIN inlined uthread_sem.c. This is done here so that no extra libraries
234 * or include files not present in BSD/OS are required
235 */
236
237 /*
238 * Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
239 * All rights reserved.
240 *
241 * Redistribution and use in source and binary forms, with or without
242 * modification, are permitted provided that the following conditions
243 * are met:
244 * 1. Redistributions of source code must retain the above copyright
245 * notice(s), this list of conditions and the following disclaimer as
246 * the first lines of this file unmodified other than the possible
247 * addition of one or more copyright notices.
248 * 2. Redistributions in binary form must reproduce the above copyright
249 * notice(s), this list of conditions and the following disclaimer in
250 * the documentation and/or other materials provided with the
251 * distribution.
252 *
253 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
254 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
255 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
256 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
257 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
258 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
259 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
260 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
261 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
262 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
263 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
264 *
265 * $FreeBSD: src/lib/libc_r/uthread/uthread_sem.c,v 1.3.2.1 2000/07/18 02:05:57 jasone Exp $
266 */
267
268 #include <errno.h>
269 #include <semaphore.h>
270 #include <pthread.h>
271
272 /* Begin thread_private.h kluge */
273 /*
274 * These come out of (or should go into) thread_private.h - rather than have
275 * to copy (or symlink) the files from the source tree these definitions are
276 * inlined here. Obviously these go away when this module is part of libc.
277 */
278 struct sem {
279 #define SEM_MAGIC ((u_int32_t) 0x09fa4012)
280 u_int32_t magic;
281 pthread_mutex_t lock;
282 pthread_cond_t gtzero;
283 u_int32_t count;
284 u_int32_t nwaiters;
285 };
286
287 extern pthread_once_t _thread_init_once;
288 extern int _threads_initialized;
289 extern void _thread_init __P((void));
290 #define THREAD_INIT() \
291 (void) pthread_once(&_thread_init_once, _thread_init)
292 #define THREAD_SAFE() \
293 (_threads_initialized != 0)
294
295 #define _SEM_CHECK_VALIDITY(sem) \
296 if ((*(sem))->magic != SEM_MAGIC) { \
297 errno = EINVAL; \
298 retval = -1; \
299 goto RETURN; \
300 }
301 /* End thread_private.h kluge */
302
303 int
304 sem_init(sem_t *sem, int pshared, unsigned int value)
305 {
306 int retval;
307
308 if (!THREAD_SAFE())
309 THREAD_INIT();
310
311 /*
312 * Range check the arguments.
313 */
314 if (pshared != 0) {
315 /*
316 * The user wants a semaphore that can be shared among
317 * processes, which this implementation can't do. Sounds like a
318 * permissions problem to me (yeah right).
319 */
320 errno = EPERM;
321 retval = -1;
322 goto RETURN;
323 }
324
325 if (value > SEM_VALUE_MAX) {
326 errno = EINVAL;
327 retval = -1;
328 goto RETURN;
329 }
330
331 *sem = (sem_t)malloc(sizeof(struct sem));
332 if (*sem == NULL) {
333 errno = ENOSPC;
334 retval = -1;
335 goto RETURN;
336 }
337
338 /*
339 * Initialize the semaphore.
340 */
341 if (pthread_mutex_init(&(*sem)->lock, NULL) != 0) {
342 free(*sem);
343 errno = ENOSPC;
344 retval = -1;
345 goto RETURN;
346 }
347
348 if (pthread_cond_init(&(*sem)->gtzero, NULL) != 0) {
349 pthread_mutex_destroy(&(*sem)->lock);
350 free(*sem);
351 errno = ENOSPC;
352 retval = -1;
353 goto RETURN;
354 }
355
356 (*sem)->count = (u_int32_t)value;
357 (*sem)->nwaiters = 0;
358 (*sem)->magic = SEM_MAGIC;
359
360 retval = 0;
361 RETURN:
362 return retval;
363 }
364
365 int
366 sem_destroy(sem_t *sem)
367 {
368 int retval;
369
370 _SEM_CHECK_VALIDITY(sem);
371
372 /* Make sure there are no waiters. */
373 pthread_mutex_lock(&(*sem)->lock);
374 if ((*sem)->nwaiters > 0) {
375 pthread_mutex_unlock(&(*sem)->lock);
376 errno = EBUSY;
377 retval = -1;
378 goto RETURN;
379 }
380 pthread_mutex_unlock(&(*sem)->lock);
381
382 pthread_mutex_destroy(&(*sem)->lock);
383 pthread_cond_destroy(&(*sem)->gtzero);
384 (*sem)->magic = 0;
385
386 free(*sem);
387
388 retval = 0;
389 RETURN:
390 return retval;
391 }
392
393 sem_t *
394 sem_open(const char *name, int oflag, ...)
395 {
396 errno = ENOSYS;
397 return SEM_FAILED;
398 }
399
400 int
401 sem_close(sem_t *sem)
402 {
403 errno = ENOSYS;
404 return -1;
405 }
406
407 int
408 sem_unlink(const char *name)
409 {
410 errno = ENOSYS;
411 return -1;
412 }
413
414 int
415 sem_wait(sem_t *sem)
416 {
417 int retval;
418
419 pthread_testcancel();
420
421 _SEM_CHECK_VALIDITY(sem);
422
423 pthread_mutex_lock(&(*sem)->lock);
424
425 while ((*sem)->count == 0) {
426 (*sem)->nwaiters++;
427 pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
428 (*sem)->nwaiters--;
429 }
430 (*sem)->count--;
431
432 pthread_mutex_unlock(&(*sem)->lock);
433
434 retval = 0;
435 RETURN:
436
437 pthread_testcancel();
438 return retval;
439 }
440
441 int
442 sem_trywait(sem_t *sem)
443 {
444 int retval;
445
446 _SEM_CHECK_VALIDITY(sem);
447
448 pthread_mutex_lock(&(*sem)->lock);
449
450 if ((*sem)->count > 0) {
451 (*sem)->count--;
452 retval = 0;
453 } else {
454 errno = EAGAIN;
455 retval = -1;
456 }
457
458 pthread_mutex_unlock(&(*sem)->lock);
459
460 RETURN:
461 return retval;
462 }
463
464 int
465 sem_post(sem_t *sem)
466 {
467 int retval;
468
469 _SEM_CHECK_VALIDITY(sem);
470
471 pthread_mutex_lock(&(*sem)->lock);
472
473 (*sem)->count++;
474 if ((*sem)->nwaiters > 0) {
475 /*
476 * We must use pthread_cond_broadcast() rather than
477 * pthread_cond_signal() in order to assure that the highest
478 * priority thread is run by the scheduler, since
479 * pthread_cond_signal() signals waiting threads in FIFO order.
480 */
481 pthread_cond_broadcast(&(*sem)->gtzero);
482 }
483
484 pthread_mutex_unlock(&(*sem)->lock);
485
486 retval = 0;
487 RETURN:
488 return retval;
489 }
490
491 int
492 sem_getvalue(sem_t *sem, int *sval)
493 {
494 int retval;
495
496 _SEM_CHECK_VALIDITY(sem);
497
498 pthread_mutex_lock(&(*sem)->lock);
499 *sval = (int)(*sem)->count;
500 pthread_mutex_unlock(&(*sem)->lock);
501
502 retval = 0;
503 RETURN:
504 return retval;
505 }
506
507 /* END of inlined uthread_sem.c */
508 #endif /* SDL_USE_PTHREADS */