Mercurial > sdl-ios-xcode
annotate src/thread/linux/SDL_syssem.c @ 417:04ec6995f75d
*** empty log message ***
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Thu, 13 Jun 2002 23:59:20 +0000 |
| parents | f6ffac90895c |
| children | b8d311d90021 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
|
297
f6ffac90895c
Updated copyright information for 2002
Sam Lantinga <slouken@libsdl.org>
parents:
252
diff
changeset
|
3 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga |
| 0 | 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 | |
|
252
e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
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20 slouken@libsdl.org |
| 0 | 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 linux | |
| 34 /* Look to see if glibc is available, and if so, what version */ | |
| 35 #include <features.h> | |
| 36 | |
| 37 #if (__GLIBC__ == 2) && (__GLIBC_MINOR__ == 0) | |
| 38 #warning Working around a bug in glibc 2.0 pthreads | |
| 39 #undef SDL_USE_PTHREADS | |
| 40 /* The bug is actually a problem where threads are suspended, but don't | |
| 41 wake up when the thread manager sends them a signal. This is a problem | |
| 42 with thread creation too, but it happens less often. :-/ | |
| 43 We avoid this by using System V IPC for semaphores. | |
| 44 */ | |
| 45 #endif /* glibc 2.0 */ | |
| 46 #endif /* linux */ | |
| 47 | |
| 48 #ifdef SDL_USE_PTHREADS | |
| 49 | |
| 50 #ifdef SDL_NO_PTHREAD_SEMAPHORES | |
|
94
ae6e6b73333f
Cleaned up the OpenBSD port, thanks to Peter Valchev
Sam Lantinga <slouken@lokigames.com>
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51 #include "generic/SDL_syssem.c" |
| 0 | 52 #else |
| 53 | |
| 54 #include <stdio.h> | |
| 55 #include <stdlib.h> | |
| 56 #include <unistd.h> /* For getpid() */ | |
|
18
d9e3595b63d5
Added pthread.h - necessary on some configurations
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
57 #include <pthread.h> |
| 0 | 58 #include <semaphore.h> |
| 59 | |
| 60 /* Wrapper around POSIX 1003.1b semaphores */ | |
| 61 | |
| 62 #ifdef MACOSX | |
| 63 #define USE_NAMED_SEMAPHORES | |
| 64 /* Broken sem_getvalue() in MacOS X Public Beta */ | |
| 65 #define BROKEN_SEMGETVALUE | |
| 66 #endif /* MACOSX */ | |
| 67 | |
| 68 struct SDL_semaphore { | |
| 69 sem_t *sem; | |
| 70 #ifndef USE_NAMED_SEMAPHORES | |
| 71 sem_t sem_data; | |
| 72 #endif | |
| 73 #ifdef BROKEN_SEMGETVALUE | |
| 74 /* This is a little hack for MacOS X - | |
| 75 It's not thread-safe, but it's better than nothing | |
| 76 */ | |
| 77 int sem_value; | |
| 78 #endif | |
| 79 }; | |
| 80 | |
| 81 /* Create a semaphore, initialized with value */ | |
| 82 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 83 { | |
| 84 SDL_sem *sem = (SDL_sem *) malloc(sizeof(SDL_sem)); | |
| 85 if ( sem ) { | |
| 86 #ifdef USE_NAMED_SEMAPHORES | |
| 87 static int semnum = 0; | |
| 88 char name[32]; | |
| 89 | |
| 90 sprintf(name, "/SDL_sem-%d-%4.4d", getpid(), semnum++); | |
| 91 sem->sem = sem_open(name, O_CREAT, 0600, initial_value); | |
| 92 if ( sem->sem == (sem_t *)SEM_FAILED ) { | |
| 93 SDL_SetError("sem_open(%s) failed", name); | |
| 94 free(sem); | |
| 95 sem = NULL; | |
| 96 } else { | |
| 97 sem_unlink(name); | |
| 98 } | |
| 99 #else | |
| 100 if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) { | |
| 101 SDL_SetError("sem_init() failed"); | |
| 102 free(sem); | |
| 103 sem = NULL; | |
| 104 } else { | |
| 105 sem->sem = &sem->sem_data; | |
| 106 } | |
| 107 #endif /* USE_NAMED_SEMAPHORES */ | |
| 108 | |
| 109 #ifdef BROKEN_SEMGETVALUE | |
| 110 if ( sem ) { | |
| 111 sem->sem_value = initial_value; | |
| 112 } | |
| 113 #endif /* BROKEN_SEMGETVALUE */ | |
| 114 } else { | |
| 115 SDL_OutOfMemory(); | |
| 116 } | |
| 117 return sem; | |
| 118 } | |
| 119 | |
| 120 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 121 { | |
| 122 if ( sem ) { | |
| 123 #ifdef USE_NAMED_SEMAPHORES | |
| 124 sem_close(sem->sem); | |
| 125 #else | |
| 126 sem_destroy(sem->sem); | |
| 127 #endif | |
| 128 free(sem); | |
| 129 } | |
| 130 } | |
| 131 | |
| 132 int SDL_SemTryWait(SDL_sem *sem) | |
| 133 { | |
| 134 int retval; | |
| 135 | |
| 136 if ( ! sem ) { | |
| 137 SDL_SetError("Passed a NULL semaphore"); | |
| 138 return -1; | |
| 139 } | |
| 140 retval = SDL_MUTEX_TIMEDOUT; | |
| 141 if ( sem_trywait(sem->sem) == 0 ) { | |
| 142 #ifdef BROKEN_SEMGETVALUE | |
| 143 --sem->sem_value; | |
| 144 #endif | |
| 145 retval = 0; | |
| 146 } | |
| 147 return retval; | |
| 148 } | |
| 149 | |
| 150 int SDL_SemWait(SDL_sem *sem) | |
| 151 { | |
| 152 int retval; | |
| 153 | |
| 154 if ( ! sem ) { | |
| 155 SDL_SetError("Passed a NULL semaphore"); | |
| 156 return -1; | |
| 157 } | |
| 158 | |
| 159 #ifdef BROKEN_SEMGETVALUE | |
| 160 --sem->sem_value; | |
| 161 #endif | |
| 162 retval = sem_wait(sem->sem); | |
| 163 if ( retval < 0 ) { | |
| 164 SDL_SetError("sem_wait() failed"); | |
| 165 } | |
| 166 return retval; | |
| 167 } | |
| 168 | |
| 169 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 170 { | |
| 171 int retval; | |
| 172 | |
| 173 if ( ! sem ) { | |
| 174 SDL_SetError("Passed a NULL semaphore"); | |
| 175 return -1; | |
| 176 } | |
| 177 | |
| 178 /* Try the easy cases first */ | |
| 179 if ( timeout == 0 ) { | |
| 180 return SDL_SemTryWait(sem); | |
| 181 } | |
| 182 if ( timeout == SDL_MUTEX_MAXWAIT ) { | |
| 183 return SDL_SemWait(sem); | |
| 184 } | |
| 185 | |
| 186 /* Ack! We have to busy wait... */ | |
| 187 timeout += SDL_GetTicks(); | |
| 188 do { | |
| 189 retval = SDL_SemTryWait(sem); | |
| 190 if ( retval == 0 ) { | |
| 191 break; | |
| 192 } | |
| 193 SDL_Delay(1); | |
| 194 } while ( SDL_GetTicks() < timeout ); | |
| 195 | |
| 196 return retval; | |
| 197 } | |
| 198 | |
| 199 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 200 { | |
| 201 int ret = 0; | |
| 202 if ( sem ) { | |
| 203 #ifdef BROKEN_SEMGETVALUE | |
| 204 ret = sem->sem_value; | |
| 205 #else | |
| 206 sem_getvalue(sem->sem, &ret); | |
| 207 #endif | |
| 208 if ( ret < 0 ) { | |
| 209 ret = 0; | |
| 210 } | |
| 211 } | |
| 212 return (Uint32)ret; | |
| 213 } | |
| 214 | |
| 215 int SDL_SemPost(SDL_sem *sem) | |
| 216 { | |
| 217 int retval; | |
| 218 | |
| 219 if ( ! sem ) { | |
| 220 SDL_SetError("Passed a NULL semaphore"); | |
| 221 return -1; | |
| 222 } | |
| 223 | |
| 224 #ifdef BROKEN_SEMGETVALUE | |
| 225 ++sem->sem_value; | |
| 226 #endif | |
| 227 retval = sem_post(sem->sem); | |
| 228 if ( retval < 0 ) { | |
| 229 SDL_SetError("sem_post() failed"); | |
| 230 } | |
| 231 return retval; | |
| 232 } | |
| 233 | |
| 234 #endif /* NO_PTHREAD_SEMAPHORES */ | |
| 235 | |
| 236 #else /* System V IPC implementation */ | |
| 237 | |
| 238 #include <stdio.h> | |
| 239 #include <stdlib.h> | |
| 240 #include <sys/types.h> | |
| 241 #include <sys/ipc.h> | |
| 242 #include <sys/sem.h> | |
| 243 #include <errno.h> | |
| 244 | |
| 245 #include "SDL_error.h" | |
| 246 #include "SDL_thread.h" | |
| 247 | |
| 248 | |
| 249 struct SDL_semaphore { | |
| 250 int id; | |
| 251 }; | |
| 252 | |
| 253 /* Not defined by many operating systems, use configure to detect */ | |
| 254 #if !defined(HAVE_SEMUN) | |
| 255 union semun { | |
| 256 int val; | |
| 257 struct semid_ds *buf; | |
| 258 ushort *array; | |
| 259 }; | |
| 260 #endif | |
| 261 | |
| 262 static struct sembuf op_trywait[2] = { | |
| 263 { 0, -1, (IPC_NOWAIT|SEM_UNDO) } /* Decrement semaphore, no block */ | |
| 264 }; | |
| 265 static struct sembuf op_wait[2] = { | |
| 266 { 0, -1, SEM_UNDO } /* Decrement semaphore */ | |
| 267 }; | |
| 268 static struct sembuf op_post[1] = { | |
| 269 { 0, 1, (IPC_NOWAIT|SEM_UNDO) } /* Increment semaphore */ | |
| 270 }; | |
| 271 | |
| 272 /* Create a blockable semaphore */ | |
| 273 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 274 { | |
| 275 extern int _creating_thread_lock; /* SDL_threads.c */ | |
| 276 SDL_sem *sem; | |
| 277 union semun init; | |
| 278 key_t key; | |
| 279 | |
| 280 sem = (SDL_sem *)malloc(sizeof(*sem)); | |
| 281 if ( sem == NULL ) { | |
| 282 SDL_OutOfMemory(); | |
| 283 return(NULL); | |
| 284 } | |
| 285 /* This flag is true if we are creating the thread manager sem, | |
| 286 which is never freed. This allows us to reuse the same sem. | |
| 287 */ | |
| 288 if ( _creating_thread_lock ) { | |
| 289 key = 'S'+'D'+'L'; | |
| 290 } else { | |
| 291 key = IPC_PRIVATE; | |
| 292 } | |
| 293 /* Keep trying to create sem while we don't own the requested key */ | |
| 294 do { | |
| 295 if ( key != IPC_PRIVATE ) { | |
| 296 ++key; | |
| 297 } | |
| 298 sem->id = semget(key, 1, (0600|IPC_CREAT)); | |
| 299 } while ((sem->id < 0) && (key != IPC_PRIVATE) && (errno == EACCES)); | |
| 300 | |
| 301 /* Report the error if we eventually failed */ | |
| 302 if ( sem->id < 0 ) { | |
| 303 SDL_SetError("Couldn't create semaphore"); | |
| 304 free(sem); | |
| 305 return(NULL); | |
| 306 } | |
| 307 init.val = initial_value; /* Initialize semaphore */ | |
| 308 semctl(sem->id, 0, SETVAL, init); | |
| 309 return(sem); | |
| 310 } | |
| 311 | |
| 312 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 313 { | |
| 314 if ( sem ) { | |
| 315 #ifdef _SGI_SOURCE | |
| 316 semctl(sem->id, 0, IPC_RMID); | |
| 317 #else | |
| 318 union semun dummy; | |
| 319 dummy.val = 0; | |
| 320 semctl(sem->id, 0, IPC_RMID, dummy); | |
| 321 #endif | |
| 322 free(sem); | |
| 323 } | |
| 324 } | |
| 325 | |
| 326 int SDL_SemTryWait(SDL_sem *sem) | |
| 327 { | |
| 328 int retval; | |
| 329 | |
| 330 if ( ! sem ) { | |
| 331 SDL_SetError("Passed a NULL semaphore"); | |
| 332 return -1; | |
| 333 } | |
| 334 | |
| 335 retval = 0; | |
| 336 tryagain: | |
| 337 if ( semop(sem->id, op_trywait, 1) < 0 ) { | |
| 338 if ( errno == EINTR ) { | |
| 339 goto tryagain; | |
| 340 } | |
| 341 retval = SDL_MUTEX_TIMEDOUT; | |
| 342 } | |
| 343 return retval; | |
| 344 } | |
| 345 | |
| 346 int SDL_SemWait(SDL_sem *sem) | |
| 347 { | |
| 348 int retval; | |
| 349 | |
| 350 if ( ! sem ) { | |
| 351 SDL_SetError("Passed a NULL semaphore"); | |
| 352 return -1; | |
| 353 } | |
| 354 | |
| 355 retval = 0; | |
| 356 tryagain: | |
| 357 if ( semop(sem->id, op_wait, 1) < 0 ) { | |
| 358 if ( errno == EINTR ) { | |
| 359 goto tryagain; | |
| 360 } | |
| 361 SDL_SetError("Semaphore operation error"); | |
| 362 retval = -1; | |
| 363 } | |
| 364 return retval; | |
| 365 } | |
| 366 | |
| 367 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 368 { | |
| 369 int retval; | |
| 370 | |
| 371 if ( ! sem ) { | |
| 372 SDL_SetError("Passed a NULL semaphore"); | |
| 373 return -1; | |
| 374 } | |
| 375 | |
| 376 /* Try the easy cases first */ | |
| 377 if ( timeout == 0 ) { | |
| 378 return SDL_SemTryWait(sem); | |
| 379 } | |
| 380 if ( timeout == SDL_MUTEX_MAXWAIT ) { | |
| 381 return SDL_SemWait(sem); | |
| 382 } | |
| 383 | |
| 384 /* Ack! We have to busy wait... */ | |
| 385 timeout += SDL_GetTicks(); | |
| 386 do { | |
| 387 retval = SDL_SemTryWait(sem); | |
| 388 if ( retval == 0 ) { | |
| 389 break; | |
| 390 } | |
| 391 SDL_Delay(1); | |
| 392 } while ( SDL_GetTicks() < timeout ); | |
| 393 | |
| 394 return retval; | |
| 395 } | |
| 396 | |
| 397 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 398 { | |
| 399 int semval; | |
| 400 Uint32 value; | |
| 401 | |
| 402 value = 0; | |
| 403 if ( sem ) { | |
| 404 tryagain: | |
| 405 #ifdef _SGI_SOURCE | |
| 406 semval = semctl(sem->id, 0, GETVAL); | |
| 407 #else | |
| 408 { | |
| 409 union semun arg; | |
| 410 arg.val = 0; | |
| 411 semval = semctl(sem->id, 0, GETVAL, arg); | |
| 412 } | |
| 413 #endif | |
| 414 if ( semval < 0 ) { | |
| 415 if ( errno == EINTR ) { | |
| 416 goto tryagain; | |
| 417 } | |
| 418 } else { | |
| 419 value = (Uint32)semval; | |
| 420 } | |
| 421 } | |
| 422 return value; | |
| 423 } | |
| 424 | |
| 425 int SDL_SemPost(SDL_sem *sem) | |
| 426 { | |
| 427 int retval; | |
| 428 | |
| 429 if ( ! sem ) { | |
| 430 SDL_SetError("Passed a NULL semaphore"); | |
| 431 return -1; | |
| 432 } | |
| 433 | |
| 434 retval = 0; | |
| 435 tryagain: | |
| 436 if ( semop(sem->id, op_post, 1) < 0 ) { | |
| 437 if ( errno == EINTR ) { | |
| 438 goto tryagain; | |
| 439 } | |
| 440 SDL_SetError("Semaphore operation error"); | |
| 441 retval = -1; | |
| 442 } | |
| 443 return retval; | |
| 444 } | |
| 445 | |
| 446 #endif /* SDL_USE_PTHREADS */ |