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     if (!cond) return thrd_error;
 106     pthread_cond_broadcast(cond);
 107     return thrd_success;
 108 }
 109
 110 // 7.25.3.2
 111 static inline void
 112 cnd_destroy(cnd_t *cond)
 113 {
 114     assert(cond);
 115     pthread_cond_destroy(cond);
 116 }
 117
 118 // 7.25.3.3
 119 static inline int
 120 cnd_init(cnd_t *cond)
 121 {
 122     if (!cond) return thrd_error;
 123     pthread_cond_init(cond, NULL);
 124     return thrd_success;
 125 }
 126
 127 // 7.25.3.4
 128 static inline int
 129 cnd_signal(cnd_t *cond)
 130 {
 131     if (!cond) return thrd_error;
 132     pthread_cond_signal(cond);
 133     return thrd_success;
 134 }
 135
 136 // 7.25.3.5
 137 static inline int
 138 cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
 139 {
 140     struct timespec abs_time;
 141     int rt;
 142     if (!cond || !mtx || !xt) return thrd_error;
 143     rt = pthread_cond_timedwait(cond, mtx, &abs_time);
 144     if (rt == ETIMEDOUT)
 145         return thrd_busy;
 146     return (rt == 0) ? thrd_success : thrd_error;
 147 }
 148
 149 // 7.25.3.6
 150 static inline int
 151 cnd_wait(cnd_t *cond, mtx_t *mtx)
 152 {
 153     if (!cond || !mtx) return thrd_error;
 154     pthread_cond_wait(cond, mtx);
 155     return thrd_success;
 156 }
 157
 158
 159 /*-------------------- 7.25.4 Mutex functions --------------------*/
 160 // 7.25.4.1
 161 static inline void
 162 mtx_destroy(mtx_t *mtx)
 163 {
 164     assert(mtx);
 165     pthread_mutex_destroy(mtx);
 166 }
 167
 168 // 7.25.4.2
 169 static inline int
 170 mtx_init(mtx_t *mtx, int type)
 171 {
 172     pthread_mutexattr_t attr;
 173     if (!mtx) return thrd_error;
 174     if (type != mtx_plain && type != mtx_timed && type != mtx_try
 175       && type != (mtx_plain|mtx_recursive)
 176       && type != (mtx_timed|mtx_recursive)
 177       && type != (mtx_try|mtx_recursive))
 178         return thrd_error;
 179     pthread_mutexattr_init(&attr);
 180     if ((type & mtx_recursive) != 0) {
 181 #if defined(__linux__) || defined(__linux)
 182         pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
 183 #else
 184         pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
 185 #endif
 186     }
 187     pthread_mutex_init(mtx, &attr);
 188     pthread_mutexattr_destroy(&attr);
 189     return thrd_success;
 190 }
 191
 192 // 7.25.4.3
 193 static inline int
 194 mtx_lock(mtx_t *mtx)
 195 {
 196     if (!mtx) return thrd_error;
 197     pthread_mutex_lock(mtx);
 198     return thrd_success;
 199 }
 200
 201 static inline int
 202 mtx_trylock(mtx_t *mtx);
 203
 204 static inline void
 205 thrd_yield(void);
 206
 207 // 7.25.4.4
 208 static inline int
 209 mtx_timedlock(mtx_t *mtx, const xtime *xt)
 210 {
 211     if (!mtx || !xt) return thrd_error;
 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     if (!mtx) return thrd_error;
 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     if (!mtx) return thrd_error;
 250     pthread_mutex_unlock(mtx);
 251     return thrd_success;
 252 }
 253
 254
 255 /*------------------- 7.25.5 Thread functions -------------------*/
 256 // 7.25.5.1
 257 static inline int
 258 thrd_create(thrd_t *thr, thrd_start_t func, void *arg)
 259 {
 260     struct impl_thrd_param *pack;
 261     if (!thr) return thrd_error;
 262     pack = (struct impl_thrd_param *)malloc(sizeof(struct impl_thrd_param));
 263     if (!pack) return thrd_nomem;
 264     pack->func = func;
 265     pack->arg = arg;
 266     if (pthread_create(thr, NULL, impl_thrd_routine, pack) != 0) {
 267         free(pack);
 268         return thrd_error;
 269     }
 270     return thrd_success;
 271 }
 272
 273 // 7.25.5.2
 274 static inline thrd_t
 275 thrd_current(void)
 276 {
 277     return pthread_self();
 278 }
 279
 280 // 7.25.5.3
 281 static inline int
 282 thrd_detach(thrd_t thr)
 283 {
 284     return (pthread_detach(thr) == 0) ? thrd_success : thrd_error;
 285 }
 286
 287 // 7.25.5.4
 288 static inline int
 289 thrd_equal(thrd_t thr0, thrd_t thr1)
 290 {
 291     return pthread_equal(thr0, thr1);
 292 }
 293
 294 // 7.25.5.5
 295 static inline void
 296 thrd_exit(int res)
 297 {
 298     pthread_exit((void*)(intptr_t)res);
 299 }
 300
 301 // 7.25.5.6
 302 static inline int
 303 thrd_join(thrd_t thr, int *res)
 304 {
 305     void *code;
 306     if (pthread_join(thr, &code) != 0)
 307         return thrd_error;
 308     if (res)
 309         *res = (int)(intptr_t)code;
 310     return thrd_success;
 311 }
 312
 313 // 7.25.5.7
 314 static inline void
 315 thrd_sleep(const xtime *xt)
 316 {
 317     struct timespec req;
 318     assert(xt);
 319     req.tv_sec = xt->sec;
 320     req.tv_nsec = xt->nsec;
 321     nanosleep(&req, NULL);
 322 }
 323
 324 // 7.25.5.8
 325 static inline void
 326 thrd_yield(void)
 327 {
 328     sched_yield();
 329 }
 330
 331
 332 /*----------- 7.25.6 Thread-specific storage functions -----------*/
 333 // 7.25.6.1
 334 static inline int
 335 tss_create(tss_t *key, tss_dtor_t dtor)
 336 {
 337     if (!key) return thrd_error;
 338     return (pthread_key_create(key, dtor) == 0) ? thrd_success : thrd_error;
 339 }
 340
 341 // 7.25.6.2
 342 static inline void
 343 tss_delete(tss_t key)
 344 {
 345     pthread_key_delete(key);
 346 }
 347
 348 // 7.25.6.3
 349 static inline void *
 350 tss_get(tss_t key)
 351 {
 352     return pthread_getspecific(key);
 353 }
 354
 355 // 7.25.6.4
 356 static inline int
 357 tss_set(tss_t key, void *val)
 358 {
 359     return (pthread_setspecific(key, val) == 0) ? thrd_success : thrd_error;
 360 }
 361
 362
 363 /*-------------------- 7.25.7 Time functions --------------------*/
 364 // 7.25.6.1
 365 static inline int
 366 xtime_get(xtime *xt, int base)
 367 {
 368     if (!xt) return 0;
 369     if (base == TIME_UTC) {
 370         xt->sec = time(NULL);
 371         xt->nsec = 0;
 372         return base;
 373     }
 374     return 0;
 375 }