include/c11/threads_posix.h

   1 /*
   2  * C11 <threads.h> emulation library
   3  *
   4  * (C) Copyright yohhoy 2012.
   5  * Distributed under the Boost Software License, Version 1.0.
   6  *
   7  * Permission is hereby granted, free of charge, to any person or organization
   8  * obtaining a copy of the software and accompanying documentation covered by
   9  * this license (the "Software") to use, reproduce, display, distribute,
  10  * execute, and transmit the Software, and to prepare [[derivative work]]s of the
  11  * Software, and to permit third-parties to whom the Software is furnished to
  12  * do so, all subject to the following:
  13  *
  14  * The copyright notices in the Software and this entire statement, including
  15  * the above license grant, this restriction and the following disclaimer,
  16  * must be included in all copies of the Software, in whole or in part, and
  17  * all derivative works of the Software, unless such copies or derivative
  18  * works are solely in the form of machine-executable object code generated by
  19  * a source language processor.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23  * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  24  * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  25  * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  26  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  27  * DEALINGS IN THE SOFTWARE.
  28  */
  29 #include <stdlib.h>
  30 #ifndef assert
  31 #include <assert.h>
  32 #endif
  33 #include <limits.h>
  34 #include <errno.h>
  35 #include <unistd.h>
  36 #include <sched.h>
  37 #include <stdint.h> /* for intptr_t */
  38
  39 /*
  40 Configuration macro:
  41
  42   EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
  43     Use pthread_mutex_timedlock() for `mtx_timedlock()'
  44     Otherwise use mtx_trylock() + *busy loop* emulation.
  45 */
  46 #if !defined(__CYGWIN__) && !defined(__APPLE__) && !defined(__NetBSD__)
  47 #define EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
  48 #endif
  49
  50
  51 #include <pthread.h>
  52
  53 /*---------------------------- macros ----------------------------*/
  54 #define ONCE_FLAG_INIT PTHREAD_ONCE_INIT
  55 #ifdef INIT_ONCE_STATIC_INIT
  56 #define TSS_DTOR_ITERATIONS PTHREAD_DESTRUCTOR_ITERATIONS
  57 #else
  58 #define TSS_DTOR_ITERATIONS 1  // assume TSS dtor MAY be called at least once.
  59 #endif
  60
  61 // FIXME: temporary non-standard hack to ease transition
  62 #define _MTX_INITIALIZER_NP PTHREAD_MUTEX_INITIALIZER
  63
  64 /*---------------------------- types ----------------------------*/
  65 typedef pthread_cond_t  cnd_t;
  66 typedef pthread_t       thrd_t;
  67 typedef pthread_key_t   tss_t;
  68 typedef pthread_mutex_t mtx_t;
  69 typedef pthread_once_t  once_flag;
  70
  71
  72 /*
  73 Implementation limits:
  74   - Conditionally emulation for "mutex with timeout"
  75     (see EMULATED_THREADS_USE_NATIVE_TIMEDLOCK macro)
  76 */
  77 struct impl_thrd_param {
  78     thrd_start_t func;
  79     void *arg;
  80 };
  81
  82 static inline void *
  83 impl_thrd_routine(void *p)
  84 {
  85     struct impl_thrd_param pack = *((struct impl_thrd_param *)p);
  86     free(p);
  87     return (void*)(intptr_t)pack.func(pack.arg);
  88 }
  89
  90
  91 /*--------------- 7.25.2 Initialization functions ---------------*/
  92 // 7.25.2.1
  93 static inline void
  94 call_once(once_flag *flag, void (*func)(void))
  95 {
  96     pthread_once(flag, func);
  97 }
  98
  99
 100 /*------------- 7.25.3 Condition variable functions -------------*/
 101 // 7.25.3.1
 102 static inline int
 103 cnd_broadcast(cnd_t *cond)
 104 {
 105     assert(cond != NULL);
 106     return (pthread_cond_broadcast(cond) == 0) ? thrd_success : thrd_error;
 107 }
 108
 109 // 7.25.3.2
 110 static inline void
 111 cnd_destroy(cnd_t *cond)
 112 {
 113     assert(cond);
 114     pthread_cond_destroy(cond);
 115 }
 116
 117 // 7.25.3.3
 118 static inline int
 119 cnd_init(cnd_t *cond)
 120 {
 121     assert(cond != NULL);
 122     return (pthread_cond_init(cond, NULL) == 0) ? thrd_success : thrd_error;
 123 }
 124
 125 // 7.25.3.4
 126 static inline int
 127 cnd_signal(cnd_t *cond)
 128 {
 129     assert(cond != NULL);
 130     return (pthread_cond_signal(cond) == 0) ? thrd_success : thrd_error;
 131 }
 132
 133 // 7.25.3.5
 134 static inline int
 135 cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
 136 {
 137     struct timespec abs_time;
 138     int rt;
 139
 140     assert(mtx != NULL);
 141     assert(cond != NULL);
 142     assert(xt != NULL);
 143
 144     abs_time.tv_sec = xt->sec;
 145     abs_time.tv_nsec = xt->nsec;
 146
 147     rt = pthread_cond_timedwait(cond, mtx, &abs_time);
 148     if (rt == ETIMEDOUT)
 149         return thrd_busy;
 150     return (rt == 0) ? thrd_success : thrd_error;
 151 }
 152
 153 // 7.25.3.6
 154 static inline int
 155 cnd_wait(cnd_t *cond, mtx_t *mtx)
 156 {
 157     assert(mtx != NULL);
 158     assert(cond != NULL);
 159     return (pthread_cond_wait(cond, mtx) == 0) ? thrd_success : thrd_error;
 160 }
 161
 162
 163 /*-------------------- 7.25.4 Mutex functions --------------------*/
 164 // 7.25.4.1
 165 static inline void
 166 mtx_destroy(mtx_t *mtx)
 167 {
 168     assert(mtx != NULL);
 169     pthread_mutex_destroy(mtx);
 170 }
 171
 172 // 7.25.4.2
 173 static inline int
 174 mtx_init(mtx_t *mtx, int type)
 175 {
 176     pthread_mutexattr_t attr;
 177     assert(mtx != NULL);
 178     if (type != mtx_plain && type != mtx_timed && type != mtx_try
 179       && type != (mtx_plain|mtx_recursive)
 180       && type != (mtx_timed|mtx_recursive)
 181       && type != (mtx_try|mtx_recursive))
 182         return thrd_error;
 183     pthread_mutexattr_init(&attr);
 184     if ((type & mtx_recursive) != 0)
 185         pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
 186     pthread_mutex_init(mtx, &attr);
 187     pthread_mutexattr_destroy(&attr);
 188     return thrd_success;
 189 }
 190
 191 // 7.25.4.3
 192 static inline int
 193 mtx_lock(mtx_t *mtx)
 194 {
 195     assert(mtx != NULL);
 196     return (pthread_mutex_lock(mtx) == 0) ? thrd_success : thrd_error;
 197 }
 198
 199 static inline int
 200 mtx_trylock(mtx_t *mtx);
 201
 202 static inline void
 203 thrd_yield(void);
 204
 205 // 7.25.4.4
 206 static inline int
 207 mtx_timedlock(mtx_t *mtx, const xtime *xt)
 208 {
 209     assert(mtx != NULL);
 210     assert(xt != NULL);
 211
 212     {
 213 #ifdef EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
 214     struct timespec ts;
 215     int rt;
 216     ts.tv_sec = xt->sec;
 217     ts.tv_nsec = xt->nsec;
 218     rt = pthread_mutex_timedlock(mtx, &ts);
 219     if (rt == 0)
 220         return thrd_success;
 221     return (rt == ETIMEDOUT) ? thrd_busy : thrd_error;
 222 #else
 223     time_t expire = time(NULL);
 224     expire += xt->sec;
 225     while (mtx_trylock(mtx) != thrd_success) {
 226         time_t now = time(NULL);
 227         if (expire < now)
 228             return thrd_busy;
 229         // busy loop!
 230         thrd_yield();
 231     }
 232     return thrd_success;
 233 #endif
 234     }
 235 }
 236
 237 // 7.25.4.5
 238 static inline int
 239 mtx_trylock(mtx_t *mtx)
 240 {
 241     assert(mtx != NULL);
 242     return (pthread_mutex_trylock(mtx) == 0) ? thrd_success : thrd_busy;
 243 }
 244
 245 // 7.25.4.6
 246 static inline int
 247 mtx_unlock(mtx_t *mtx)
 248 {
 249     assert(mtx != NULL);
 250     return (pthread_mutex_unlock(mtx) == 0) ? thrd_success : thrd_error;
 251 }
 252
 253
 254 /*------------------- 7.25.5 Thread functions -------------------*/
 255 // 7.25.5.1
 256 static inline int
 257 thrd_create(thrd_t *thr, thrd_start_t func, void *arg)
 258 {
 259     struct impl_thrd_param *pack;
 260     assert(thr != NULL);
 261     pack = (struct impl_thrd_param *)malloc(sizeof(struct impl_thrd_param));
 262     if (!pack) return thrd_nomem;
 263     pack->func = func;
 264     pack->arg = arg;
 265     if (pthread_create(thr, NULL, impl_thrd_routine, pack) != 0) {
 266         free(pack);
 267         return thrd_error;
 268     }
 269     return thrd_success;
 270 }
 271
 272 // 7.25.5.2
 273 static inline thrd_t
 274 thrd_current(void)
 275 {
 276     return pthread_self();
 277 }
 278
 279 // 7.25.5.3
 280 static inline int
 281 thrd_detach(thrd_t thr)
 282 {
 283     return (pthread_detach(thr) == 0) ? thrd_success : thrd_error;
 284 }
 285
 286 // 7.25.5.4
 287 static inline int
 288 thrd_equal(thrd_t thr0, thrd_t thr1)
 289 {
 290     return pthread_equal(thr0, thr1);
 291 }
 292
 293 // 7.25.5.5
 294 static inline void
 295 thrd_exit(int res)
 296 {
 297     pthread_exit((void*)(intptr_t)res);
 298 }
 299
 300 // 7.25.5.6
 301 static inline int
 302 thrd_join(thrd_t thr, int *res)
 303 {
 304     void *code;
 305     if (pthread_join(thr, &code) != 0)
 306         return thrd_error;
 307     if (res)
 308         *res = (int)(intptr_t)code;
 309     return thrd_success;
 310 }
 311
 312 // 7.25.5.7
 313 static inline void
 314 thrd_sleep(const xtime *xt)
 315 {
 316     struct timespec req;
 317     assert(xt);
 318     req.tv_sec = xt->sec;
 319     req.tv_nsec = xt->nsec;
 320     nanosleep(&req, NULL);
 321 }
 322
 323 // 7.25.5.8
 324 static inline void
 325 thrd_yield(void)
 326 {
 327     sched_yield();
 328 }
 329
 330
 331 /*----------- 7.25.6 Thread-specific storage functions -----------*/
 332 // 7.25.6.1
 333 static inline int
 334 tss_create(tss_t *key, tss_dtor_t dtor)
 335 {
 336     assert(key != NULL);
 337     return (pthread_key_create(key, dtor) == 0) ? thrd_success : thrd_error;
 338 }
 339
 340 // 7.25.6.2
 341 static inline void
 342 tss_delete(tss_t key)
 343 {
 344     pthread_key_delete(key);
 345 }
 346
 347 // 7.25.6.3
 348 static inline void *
 349 tss_get(tss_t key)
 350 {
 351     return pthread_getspecific(key);
 352 }
 353
 354 // 7.25.6.4
 355 static inline int
 356 tss_set(tss_t key, void *val)
 357 {
 358     return (pthread_setspecific(key, val) == 0) ? thrd_success : thrd_error;
 359 }
 360
 361
 362 /*-------------------- 7.25.7 Time functions --------------------*/
 363 // 7.25.6.1
 364 static inline int
 365 xtime_get(xtime *xt, int base)
 366 {
 367     if (!xt) return 0;
 368     if (base == TIME_UTC) {
 369         xt->sec = time(NULL);
 370         xt->nsec = 0;
 371         return base;
 372     }
 373     return 0;
 374 }