include/c11/threads_win32.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 #ifndef assert
  30 #include <assert.h>
  31 #endif
  32 #include <limits.h>
  33 #include <errno.h>
  34 #include <process.h>  // MSVCRT
  35 #include <stdlib.h>
  36
  37 /*
  38 Configuration macro:
  39
  40   EMULATED_THREADS_USE_NATIVE_CALL_ONCE
  41     Use native WindowsAPI one-time initialization function.
  42     (requires WinVista or later)
  43     Otherwise emulate by mtx_trylock() + *busy loop* for WinXP.
  44
  45   EMULATED_THREADS_USE_NATIVE_CV
  46     Use native WindowsAPI condition variable object.
  47     (requires WinVista or later)
  48     Otherwise use emulated implementation for WinXP.
  49
  50   EMULATED_THREADS_TSS_DTOR_SLOTNUM
  51     Max registerable TSS dtor number.
  52 */
  53
  54 // XXX: Retain XP compatability
  55 #if 0
  56 #if _WIN32_WINNT >= 0x0600
  57 // Prefer native WindowsAPI on newer environment.
  58 #if !defined(__MINGW32__)
  59 #define EMULATED_THREADS_USE_NATIVE_CALL_ONCE
  60 #endif
  61 #define EMULATED_THREADS_USE_NATIVE_CV
  62 #endif
  63 #endif
  64 #define EMULATED_THREADS_TSS_DTOR_SLOTNUM 64  // see TLS_MINIMUM_AVAILABLE
  65
  66
  67 #include <windows.h>
  68
  69 // check configuration
  70 #if defined(EMULATED_THREADS_USE_NATIVE_CALL_ONCE) && (_WIN32_WINNT < 0x0600)
  71 #error EMULATED_THREADS_USE_NATIVE_CALL_ONCE requires _WIN32_WINNT>=0x0600
  72 #endif
  73
  74 #if defined(EMULATED_THREADS_USE_NATIVE_CV) && (_WIN32_WINNT < 0x0600)
  75 #error EMULATED_THREADS_USE_NATIVE_CV requires _WIN32_WINNT>=0x0600
  76 #endif
  77
  78
  79 /*---------------------------- macros ----------------------------*/
  80 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
  81 #define ONCE_FLAG_INIT INIT_ONCE_STATIC_INIT
  82 #else
  83 #define ONCE_FLAG_INIT {0}
  84 #endif
  85 #define TSS_DTOR_ITERATIONS 1
  86
  87 // FIXME: temporary non-standard hack to ease transition
  88 #define _MTX_INITIALIZER_NP {(PCRITICAL_SECTION_DEBUG)-1, -1, 0, 0, 0, 0}
  89
  90 /*---------------------------- types ----------------------------*/
  91 typedef struct cnd_t {
  92 #ifdef EMULATED_THREADS_USE_NATIVE_CV
  93     CONDITION_VARIABLE condvar;
  94 #else
  95     int blocked;
  96     int gone;
  97     int to_unblock;
  98     HANDLE sem_queue;
  99     HANDLE sem_gate;
 100     CRITICAL_SECTION monitor;
 101 #endif
 102 } cnd_t;
 103
 104 typedef HANDLE thrd_t;
 105
 106 typedef DWORD tss_t;
 107
 108 typedef CRITICAL_SECTION mtx_t;
 109
 110 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
 111 typedef INIT_ONCE once_flag;
 112 #else
 113 typedef struct once_flag_t {
 114     volatile LONG status;
 115 } once_flag;
 116 #endif
 117
 118
 119 static inline void * tss_get(tss_t key);
 120 static inline void thrd_yield(void);
 121 static inline int mtx_trylock(mtx_t *mtx);
 122 static inline int mtx_lock(mtx_t *mtx);
 123 static inline int mtx_unlock(mtx_t *mtx);
 124
 125 /*
 126 Implementation limits:
 127   - Conditionally emulation for "Initialization functions"
 128     (see EMULATED_THREADS_USE_NATIVE_CALL_ONCE macro)
 129   - Emulated `mtx_timelock()' with mtx_trylock() + *busy loop*
 130 */
 131 static void impl_tss_dtor_invoke(void);  // forward decl.
 132
 133 struct impl_thrd_param {
 134     thrd_start_t func;
 135     void *arg;
 136 };
 137
 138 static unsigned __stdcall impl_thrd_routine(void *p)
 139 {
 140     struct impl_thrd_param pack;
 141     int code;
 142     memcpy(&pack, p, sizeof(struct impl_thrd_param));
 143     free(p);
 144     code = pack.func(pack.arg);
 145     impl_tss_dtor_invoke();
 146     return (unsigned)code;
 147 }
 148
 149 static DWORD impl_xtime2msec(const xtime *xt)
 150 {
 151     return (DWORD)((xt->sec * 1000U) + (xt->nsec / 1000000L));
 152 }
 153
 154 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
 155 struct impl_call_once_param { void (*func)(void); };
 156 static BOOL CALLBACK impl_call_once_callback(PINIT_ONCE InitOnce, PVOID Parameter, PVOID *Context)
 157 {
 158     struct impl_call_once_param *param = (struct impl_call_once_param*)Parameter;
 159     (param->func)();
 160     ((void)InitOnce); ((void)Context);  // suppress warning
 161     return TRUE;
 162 }
 163 #endif  // ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
 164
 165 #ifndef EMULATED_THREADS_USE_NATIVE_CV
 166 /*
 167 Note:
 168   The implementation of condition variable is ported from Boost.Interprocess
 169   See http://www.boost.org/boost/interprocess/sync/windows/condition.hpp
 170 */
 171 static void impl_cond_do_signal(cnd_t *cond, int broadcast)
 172 {
 173     int nsignal = 0;
 174
 175     EnterCriticalSection(&cond->monitor);
 176     if (cond->to_unblock != 0) {
 177         if (cond->blocked == 0) {
 178             LeaveCriticalSection(&cond->monitor);
 179             return;
 180         }
 181         if (broadcast) {
 182             cond->to_unblock += nsignal = cond->blocked;
 183             cond->blocked = 0;
 184         } else {
 185             nsignal = 1;
 186             cond->to_unblock++;
 187             cond->blocked--;
 188         }
 189     } else if (cond->blocked > cond->gone) {
 190         WaitForSingleObject(cond->sem_gate, INFINITE);
 191         if (cond->gone != 0) {
 192             cond->blocked -= cond->gone;
 193             cond->gone = 0;
 194         }
 195         if (broadcast) {
 196             nsignal = cond->to_unblock = cond->blocked;
 197             cond->blocked = 0;
 198         } else {
 199             nsignal = cond->to_unblock = 1;
 200             cond->blocked--;
 201         }
 202     }
 203     LeaveCriticalSection(&cond->monitor);
 204
 205     if (0 < nsignal)
 206         ReleaseSemaphore(cond->sem_queue, nsignal, NULL);
 207 }
 208
 209 static int impl_cond_do_wait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
 210 {
 211     int nleft = 0;
 212     int ngone = 0;
 213     int timeout = 0;
 214     DWORD w;
 215
 216     WaitForSingleObject(cond->sem_gate, INFINITE);
 217     cond->blocked++;
 218     ReleaseSemaphore(cond->sem_gate, 1, NULL);
 219
 220     mtx_unlock(mtx);
 221
 222     w = WaitForSingleObject(cond->sem_queue, xt ? impl_xtime2msec(xt) : INFINITE);
 223     timeout = (w == WAIT_TIMEOUT);
 224
 225     EnterCriticalSection(&cond->monitor);
 226     if ((nleft = cond->to_unblock) != 0) {
 227         if (timeout) {
 228             if (cond->blocked != 0) {
 229                 cond->blocked--;
 230             } else {
 231                 cond->gone++;
 232             }
 233         }
 234         if (--cond->to_unblock == 0) {
 235             if (cond->blocked != 0) {
 236                 ReleaseSemaphore(cond->sem_gate, 1, NULL);
 237                 nleft = 0;
 238             }
 239             else if ((ngone = cond->gone) != 0) {
 240                 cond->gone = 0;
 241             }
 242         }
 243     } else if (++cond->gone == INT_MAX/2) {
 244         WaitForSingleObject(cond->sem_gate, INFINITE);
 245         cond->blocked -= cond->gone;
 246         ReleaseSemaphore(cond->sem_gate, 1, NULL);
 247         cond->gone = 0;
 248     }
 249     LeaveCriticalSection(&cond->monitor);
 250
 251     if (nleft == 1) {
 252         while (ngone--)
 253             WaitForSingleObject(cond->sem_queue, INFINITE);
 254         ReleaseSemaphore(cond->sem_gate, 1, NULL);
 255     }
 256
 257     mtx_lock(mtx);
 258     return timeout ? thrd_busy : thrd_success;
 259 }
 260 #endif  // ifndef EMULATED_THREADS_USE_NATIVE_CV
 261
 262 static struct impl_tss_dtor_entry {
 263     tss_t key;
 264     tss_dtor_t dtor;
 265 } impl_tss_dtor_tbl[EMULATED_THREADS_TSS_DTOR_SLOTNUM];
 266
 267 static int impl_tss_dtor_register(tss_t key, tss_dtor_t dtor)
 268 {
 269     int i;
 270     for (i = 0; i < EMULATED_THREADS_TSS_DTOR_SLOTNUM; i++) {
 271         if (!impl_tss_dtor_tbl[i].dtor)
 272             break;
 273     }
 274     if (i == EMULATED_THREADS_TSS_DTOR_SLOTNUM)
 275         return 1;
 276     impl_tss_dtor_tbl[i].key = key;
 277     impl_tss_dtor_tbl[i].dtor = dtor;
 278     return 0;
 279 }
 280
 281 static void impl_tss_dtor_invoke()
 282 {
 283     int i;
 284     for (i = 0; i < EMULATED_THREADS_TSS_DTOR_SLOTNUM; i++) {
 285         if (impl_tss_dtor_tbl[i].dtor) {
 286             void* val = tss_get(impl_tss_dtor_tbl[i].key);
 287             if (val)
 288                 (impl_tss_dtor_tbl[i].dtor)(val);
 289         }
 290     }
 291 }
 292
 293
 294 /*--------------- 7.25.2 Initialization functions ---------------*/
 295 // 7.25.2.1
 296 static inline void
 297 call_once(once_flag *flag, void (*func)(void))
 298 {
 299     assert(flag && func);
 300 #ifdef EMULATED_THREADS_USE_NATIVE_CALL_ONCE
 301     {
 302     struct impl_call_once_param param;
 303     param.func = func;
 304     InitOnceExecuteOnce(flag, impl_call_once_callback, (PVOID)&param, NULL);
 305     }
 306 #else
 307     if (InterlockedCompareExchange(&flag->status, 1, 0) == 0) {
 308         (func)();
 309         InterlockedExchange(&flag->status, 2);
 310     } else {
 311         while (flag->status == 1) {
 312             // busy loop!
 313             thrd_yield();
 314         }
 315     }
 316 #endif
 317 }
 318
 319
 320 /*------------- 7.25.3 Condition variable functions -------------*/
 321 // 7.25.3.1
 322 static inline int
 323 cnd_broadcast(cnd_t *cond)
 324 {
 325     if (!cond) return thrd_error;
 326 #ifdef EMULATED_THREADS_USE_NATIVE_CV
 327     WakeAllConditionVariable(&cond->condvar);
 328 #else
 329     impl_cond_do_signal(cond, 1);
 330 #endif
 331     return thrd_success;
 332 }
 333
 334 // 7.25.3.2
 335 static inline void
 336 cnd_destroy(cnd_t *cond)
 337 {
 338     assert(cond);
 339 #ifdef EMULATED_THREADS_USE_NATIVE_CV
 340     // do nothing
 341 #else
 342     CloseHandle(cond->sem_queue);
 343     CloseHandle(cond->sem_gate);
 344     DeleteCriticalSection(&cond->monitor);
 345 #endif
 346 }
 347
 348 // 7.25.3.3
 349 static inline int
 350 cnd_init(cnd_t *cond)
 351 {
 352     if (!cond) return thrd_error;
 353 #ifdef EMULATED_THREADS_USE_NATIVE_CV
 354     InitializeConditionVariable(&cond->condvar);
 355 #else
 356     cond->blocked = 0;
 357     cond->gone = 0;
 358     cond->to_unblock = 0;
 359     cond->sem_queue = CreateSemaphore(NULL, 0, LONG_MAX, NULL);
 360     cond->sem_gate = CreateSemaphore(NULL, 1, 1, NULL);
 361     InitializeCriticalSection(&cond->monitor);
 362 #endif
 363     return thrd_success;
 364 }
 365
 366 // 7.25.3.4
 367 static inline int
 368 cnd_signal(cnd_t *cond)
 369 {
 370     if (!cond) return thrd_error;
 371 #ifdef EMULATED_THREADS_USE_NATIVE_CV
 372     WakeConditionVariable(&cond->condvar);
 373 #else
 374     impl_cond_do_signal(cond, 0);
 375 #endif
 376     return thrd_success;
 377 }
 378
 379 // 7.25.3.5
 380 static inline int
 381 cnd_timedwait(cnd_t *cond, mtx_t *mtx, const xtime *xt)
 382 {
 383     if (!cond || !mtx || !xt) return thrd_error;
 384 #ifdef EMULATED_THREADS_USE_NATIVE_CV
 385     if (SleepConditionVariableCS(&cond->condvar, mtx, impl_xtime2msec(xt)))
 386         return thrd_success;
 387     return (GetLastError() == ERROR_TIMEOUT) ? thrd_busy : thrd_error;
 388 #else
 389     return impl_cond_do_wait(cond, mtx, xt);
 390 #endif
 391 }
 392
 393 // 7.25.3.6
 394 static inline int
 395 cnd_wait(cnd_t *cond, mtx_t *mtx)
 396 {
 397     if (!cond || !mtx) return thrd_error;
 398 #ifdef EMULATED_THREADS_USE_NATIVE_CV
 399     SleepConditionVariableCS(&cond->condvar, mtx, INFINITE);
 400 #else
 401     impl_cond_do_wait(cond, mtx, NULL);
 402 #endif
 403     return thrd_success;
 404 }
 405
 406
 407 /*-------------------- 7.25.4 Mutex functions --------------------*/
 408 // 7.25.4.1
 409 static inline void
 410 mtx_destroy(mtx_t *mtx)
 411 {
 412     assert(mtx);
 413     DeleteCriticalSection(mtx);
 414 }
 415
 416 // 7.25.4.2
 417 static inline int
 418 mtx_init(mtx_t *mtx, int type)
 419 {
 420     if (!mtx) return thrd_error;
 421     if (type != mtx_plain && type != mtx_timed && type != mtx_try
 422       && type != (mtx_plain|mtx_recursive)
 423       && type != (mtx_timed|mtx_recursive)
 424       && type != (mtx_try|mtx_recursive))
 425         return thrd_error;
 426     InitializeCriticalSection(mtx);
 427     return thrd_success;
 428 }
 429
 430 // 7.25.4.3
 431 static inline int
 432 mtx_lock(mtx_t *mtx)
 433 {
 434     if (!mtx) return thrd_error;
 435     EnterCriticalSection(mtx);
 436     return thrd_success;
 437 }
 438
 439 // 7.25.4.4
 440 static inline int
 441 mtx_timedlock(mtx_t *mtx, const xtime *xt)
 442 {
 443     time_t expire, now;
 444     if (!mtx || !xt) return thrd_error;
 445     expire = time(NULL);
 446     expire += xt->sec;
 447     while (mtx_trylock(mtx) != thrd_success) {
 448         now = time(NULL);
 449         if (expire < now)
 450             return thrd_busy;
 451         // busy loop!
 452         thrd_yield();
 453     }
 454     return thrd_success;
 455 }
 456
 457 // 7.25.4.5
 458 static inline int
 459 mtx_trylock(mtx_t *mtx)
 460 {
 461     if (!mtx) return thrd_error;
 462     return TryEnterCriticalSection(mtx) ? thrd_success : thrd_busy;
 463 }
 464
 465 // 7.25.4.6
 466 static inline int
 467 mtx_unlock(mtx_t *mtx)
 468 {
 469     if (!mtx) return thrd_error;
 470     LeaveCriticalSection(mtx);
 471     return thrd_success;
 472 }
 473
 474
 475 /*------------------- 7.25.5 Thread functions -------------------*/
 476 // 7.25.5.1
 477 static inline int
 478 thrd_create(thrd_t *thr, thrd_start_t func, void *arg)
 479 {
 480     struct impl_thrd_param *pack;
 481     uintptr_t handle;
 482     if (!thr) return thrd_error;
 483     pack = (struct impl_thrd_param *)malloc(sizeof(struct impl_thrd_param));
 484     if (!pack) return thrd_nomem;
 485     pack->func = func;
 486     pack->arg = arg;
 487     handle = _beginthreadex(NULL, 0, impl_thrd_routine, pack, 0, NULL);
 488     if (handle == 0) {
 489         if (errno == EAGAIN || errno == EACCES)
 490             return thrd_nomem;
 491         return thrd_error;
 492     }
 493     *thr = (thrd_t)handle;
 494     return thrd_success;
 495 }
 496
 497 #if 0
 498 // 7.25.5.2
 499 static inline thrd_t
 500 thrd_current(void)
 501 {
 502     HANDLE hCurrentThread;
 503     BOOL bRet;
 504
 505     /* GetCurrentThread() returns a pseudo-handle, which is useless.  We need
 506      * to call DuplicateHandle to get a real handle.  However the handle value
 507      * will not match the one returned by thread_create.
 508      *
 509      * Other potential solutions would be:
 510      * - define thrd_t as a thread Ids, but this would mean we'd need to OpenThread for many operations
 511      * - use malloc'ed memory for thrd_t. This would imply using TLS for current thread.
 512      *
 513      * Neither is particularly nice.
 514      *
 515      * Life would be much easier if C11 threads had different abstractions for
 516      * threads and thread IDs, just like C++11 threads does...
 517      */
 518
 519     bRet = DuplicateHandle(GetCurrentProcess(), // source process (pseudo) handle
 520                            GetCurrentThread(), // source (pseudo) handle
 521                            GetCurrentProcess(), // target process
 522                            &hCurrentThread, // target handle
 523                            0,
 524                            FALSE,
 525                            DUPLICATE_SAME_ACCESS);
 526     assert(bRet);
 527     if (!bRet) {
 528         hCurrentThread = GetCurrentThread();
 529     }
 530     return hCurrentThread;
 531 }
 532 #endif
 533
 534 // 7.25.5.3
 535 static inline int
 536 thrd_detach(thrd_t thr)
 537 {
 538     CloseHandle(thr);
 539     return thrd_success;
 540 }
 541
 542 // 7.25.5.4
 543 static inline int
 544 thrd_equal(thrd_t thr0, thrd_t thr1)
 545 {
 546     return GetThreadId(thr0) == GetThreadId(thr1);
 547 }
 548
 549 // 7.25.5.5
 550 static inline void
 551 thrd_exit(int res)
 552 {
 553     impl_tss_dtor_invoke();
 554     _endthreadex((unsigned)res);
 555 }
 556
 557 // 7.25.5.6
 558 static inline int
 559 thrd_join(thrd_t thr, int *res)
 560 {
 561     DWORD w, code;
 562     w = WaitForSingleObject(thr, INFINITE);
 563     if (w != WAIT_OBJECT_0)
 564         return thrd_error;
 565     if (res) {
 566         if (!GetExitCodeThread(thr, &code)) {
 567             CloseHandle(thr);
 568             return thrd_error;
 569         }
 570         *res = (int)code;
 571     }
 572     CloseHandle(thr);
 573     return thrd_success;
 574 }
 575
 576 // 7.25.5.7
 577 static inline void
 578 thrd_sleep(const xtime *xt)
 579 {
 580     assert(xt);
 581     Sleep(impl_xtime2msec(xt));
 582 }
 583
 584 // 7.25.5.8
 585 static inline void
 586 thrd_yield(void)
 587 {
 588     SwitchToThread();
 589 }
 590
 591
 592 /*----------- 7.25.6 Thread-specific storage functions -----------*/
 593 // 7.25.6.1
 594 static inline int
 595 tss_create(tss_t *key, tss_dtor_t dtor)
 596 {
 597     if (!key) return thrd_error;
 598     *key = TlsAlloc();
 599     if (dtor) {
 600         if (impl_tss_dtor_register(*key, dtor)) {
 601             TlsFree(*key);
 602             return thrd_error;
 603         }
 604     }
 605     return (*key != 0xFFFFFFFF) ? thrd_success : thrd_error;
 606 }
 607
 608 // 7.25.6.2
 609 static inline void
 610 tss_delete(tss_t key)
 611 {
 612     TlsFree(key);
 613 }
 614
 615 // 7.25.6.3
 616 static inline void *
 617 tss_get(tss_t key)
 618 {
 619     return TlsGetValue(key);
 620 }
 621
 622 // 7.25.6.4
 623 static inline int
 624 tss_set(tss_t key, void *val)
 625 {
 626     return TlsSetValue(key, val) ? thrd_success : thrd_error;
 627 }
 628
 629
 630 /*-------------------- 7.25.7 Time functions --------------------*/
 631 // 7.25.6.1
 632 static inline int
 633 xtime_get(xtime *xt, int base)
 634 {
 635     if (!xt) return 0;
 636     if (base == TIME_UTC) {
 637         xt->sec = time(NULL);
 638         xt->nsec = 0;
 639         return base;
 640     }
 641     return 0;
 642 }