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         pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
 182     pthread_mutex_init(mtx, &attr);
 183     pthread_mutexattr_destroy(&attr);
 184     return thrd_success;
 185 }
 186
 187 // 7.25.4.3
 188 static inline int
 189 mtx_lock(mtx_t *mtx)
 190 {
 191     if (!mtx) return thrd_error;
 192     pthread_mutex_lock(mtx);
 193     return thrd_success;
 194 }
 195
 196 static inline int
 197 mtx_trylock(mtx_t *mtx);
 198
 199 static inline void
 200 thrd_yield(void);
 201
 202 // 7.25.4.4
 203 static inline int
 204 mtx_timedlock(mtx_t *mtx, const xtime *xt)
 205 {
 206     if (!mtx || !xt) return thrd_error;
 207     {
 208 #ifdef EMULATED_THREADS_USE_NATIVE_TIMEDLOCK
 209     struct timespec ts;
 210     int rt;
 211     ts.tv_sec = xt->sec;
 212     ts.tv_nsec = xt->nsec;
 213     rt = pthread_mutex_timedlock(mtx, &ts);
 214     if (rt == 0)
 215         return thrd_success;
 216     return (rt == ETIMEDOUT) ? thrd_busy : thrd_error;
 217 #else
 218     time_t expire = time(NULL);
 219     expire += xt->sec;
 220     while (mtx_trylock(mtx) != thrd_success) {
 221         time_t now = time(NULL);
 222         if (expire < now)
 223             return thrd_busy;
 224         // busy loop!
 225         thrd_yield();
 226     }
 227     return thrd_success;
 228 #endif
 229     }
 230 }
 231
 232 // 7.25.4.5
 233 static inline int
 234 mtx_trylock(mtx_t *mtx)
 235 {
 236     if (!mtx) return thrd_error;
 237     return (pthread_mutex_trylock(mtx) == 0) ? thrd_success : thrd_busy;
 238 }
 239
 240 // 7.25.4.6
 241 static inline int
 242 mtx_unlock(mtx_t *mtx)
 243 {
 244     if (!mtx) return thrd_error;
 245     pthread_mutex_unlock(mtx);
 246     return thrd_success;
 247 }
 248
 249
 250 /*------------------- 7.25.5 Thread functions -------------------*/
 251 // 7.25.5.1
 252 static inline int
 253 thrd_create(thrd_t *thr, thrd_start_t func, void *arg)
 254 {
 255     struct impl_thrd_param *pack;
 256     if (!thr) return thrd_error;
 257     pack = (struct impl_thrd_param *)malloc(sizeof(struct impl_thrd_param));
 258     if (!pack) return thrd_nomem;
 259     pack->func = func;
 260     pack->arg = arg;
 261     if (pthread_create(thr, NULL, impl_thrd_routine, pack) != 0) {
 262         free(pack);
 263         return thrd_error;
 264     }
 265     return thrd_success;
 266 }
 267
 268 // 7.25.5.2
 269 static inline thrd_t
 270 thrd_current(void)
 271 {
 272     return pthread_self();
 273 }
 274
 275 // 7.25.5.3
 276 static inline int
 277 thrd_detach(thrd_t thr)
 278 {
 279     return (pthread_detach(thr) == 0) ? thrd_success : thrd_error;
 280 }
 281
 282 // 7.25.5.4
 283 static inline int
 284 thrd_equal(thrd_t thr0, thrd_t thr1)
 285 {
 286     return pthread_equal(thr0, thr1);
 287 }
 288
 289 // 7.25.5.5
 290 static inline void
 291 thrd_exit(int res)
 292 {
 293     pthread_exit((void*)(intptr_t)res);
 294 }
 295
 296 // 7.25.5.6
 297 static inline int
 298 thrd_join(thrd_t thr, int *res)
 299 {
 300     void *code;
 301     if (pthread_join(thr, &code) != 0)
 302         return thrd_error;
 303     if (res)
 304         *res = (int)(intptr_t)code;
 305     return thrd_success;
 306 }
 307
 308 // 7.25.5.7
 309 static inline void
 310 thrd_sleep(const xtime *xt)
 311 {
 312     struct timespec req;
 313     assert(xt);
 314     req.tv_sec = xt->sec;
 315     req.tv_nsec = xt->nsec;
 316     nanosleep(&req, NULL);
 317 }
 318
 319 // 7.25.5.8
 320 static inline void
 321 thrd_yield(void)
 322 {
 323     sched_yield();
 324 }
 325
 326
 327 /*----------- 7.25.6 Thread-specific storage functions -----------*/
 328 // 7.25.6.1
 329 static inline int
 330 tss_create(tss_t *key, tss_dtor_t dtor)
 331 {
 332     if (!key) return thrd_error;
 333     return (pthread_key_create(key, dtor) == 0) ? thrd_success : thrd_error;
 334 }
 335
 336 // 7.25.6.2
 337 static inline void
 338 tss_delete(tss_t key)
 339 {
 340     pthread_key_delete(key);
 341 }
 342
 343 // 7.25.6.3
 344 static inline void *
 345 tss_get(tss_t key)
 346 {
 347     return pthread_getspecific(key);
 348 }
 349
 350 // 7.25.6.4
 351 static inline int
 352 tss_set(tss_t key, void *val)
 353 {
 354     return (pthread_setspecific(key, val) == 0) ? thrd_success : thrd_error;
 355 }
 356
 357
 358 /*-------------------- 7.25.7 Time functions --------------------*/
 359 // 7.25.6.1
 360 static inline int
 361 xtime_get(xtime *xt, int base)
 362 {
 363     if (!xt) return 0;
 364     if (base == TIME_UTC) {
 365         xt->sec = time(NULL);
 366         xt->nsec = 0;
 367         return base;
 368     }
 369     return 0;
 370 }