src/pthread_cond.c

   1 /*
   2  * Copyright (c) 2000-2003, 2007, 2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * Copyright 1996 1995 by Open Software Foundation, Inc. 1997 1996 1995 1994 1993 1992 1991
  25  *              All Rights Reserved
  26  *
  27  * Permission to use, copy, modify, and distribute this software and
  28  * its documentation for any purpose and without fee is hereby granted,
  29  * provided that the above copyright notice appears in all copies and
  30  * that both the copyright notice and this permission notice appear in
  31  * supporting documentation.
  32  *
  33  * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
  34  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  35  * FOR A PARTICULAR PURPOSE.
  36  *
  37  * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
  38  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  39  * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
  40  * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  41  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  42  */
  43 /*
  44  * MkLinux
  45  */
  46
  47 /*
  48  * POSIX Pthread Library
  49  */
  50
  51 #include "internal.h"
  52 #include <sys/time.h>         /* For struct timespec and getclock(). */
  53 #include <stdio.h>
  54
  55 #ifdef PLOCKSTAT
  56 #include "plockstat.h"
  57 #else /* !PLOCKSTAT */
  58 #define PLOCKSTAT_MUTEX_RELEASE(x, y)
  59 #endif /* PLOCKSTAT */
  60
  61 __private_extern__ int _pthread_cond_init(_pthread_cond *, const pthread_condattr_t *, int);
  62 __private_extern__ int _pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime, int isRelative, int isconforming);
  63
  64 extern int __gettimeofday(struct timeval *, struct timezone *);
  65
  66 #ifndef BUILDING_VARIANT
  67 static void _pthread_cond_cleanup(void *arg);
  68 static void _pthread_cond_updateval(_pthread_cond * cond, int error, uint32_t updateval);
  69 #endif
  70
  71 static void
  72 COND_GETSEQ_ADDR(_pthread_cond *cond,
  73                  volatile uint32_t **c_lseqcnt,
  74                  volatile uint32_t **c_useqcnt,
  75                  volatile uint32_t **c_sseqcnt)
  76 {
  77         if (cond->misalign) {
  78                 *c_lseqcnt = &cond->c_seq[1];
  79                 *c_sseqcnt = &cond->c_seq[2];
  80                 *c_useqcnt = &cond->c_seq[0];
  81         } else {
  82                 *c_lseqcnt = &cond->c_seq[0];
  83                 *c_sseqcnt = &cond->c_seq[1];
  84                 *c_useqcnt = &cond->c_seq[2];
  85         }
  86 }
  87
  88 #ifndef BUILDING_VARIANT /* [ */
  89
  90 int
  91 pthread_condattr_init(pthread_condattr_t *attr)
  92 {
  93         attr->sig = _PTHREAD_COND_ATTR_SIG;
  94         attr->pshared = _PTHREAD_DEFAULT_PSHARED;
  95         return 0;
  96 }
  97
  98 int
  99 pthread_condattr_destroy(pthread_condattr_t *attr)
 100 {
 101         attr->sig = _PTHREAD_NO_SIG;
 102         return 0;
 103 }
 104
 105 int
 106 pthread_condattr_getpshared(const pthread_condattr_t *attr, int *pshared)
 107 {
 108         int res = EINVAL;
 109         if (attr->sig == _PTHREAD_COND_ATTR_SIG) {
 110                 *pshared = (int)attr->pshared;
 111                 res = 0;
 112         }
 113         return res;
 114 }
 115
 116 int
 117 pthread_condattr_setpshared(pthread_condattr_t *attr, int pshared)
 118 {
 119         int res = EINVAL;
 120         if (attr->sig == _PTHREAD_COND_ATTR_SIG) {
 121 #if __DARWIN_UNIX03
 122                 if (pshared == PTHREAD_PROCESS_PRIVATE || pshared == PTHREAD_PROCESS_SHARED)
 123 #else /* __DARWIN_UNIX03 */
 124                 if (pshared == PTHREAD_PROCESS_PRIVATE)
 125 #endif /* __DARWIN_UNIX03 */
 126                 {
 127                         attr->pshared = pshared;
 128                         res = 0;
 129                 }
 130         }
 131         return res;
 132 }
 133
 134 __private_extern__ int
 135 _pthread_cond_init(_pthread_cond *cond, const pthread_condattr_t *attr, int conforming)
 136 {
 137         volatile uint32_t *c_lseqcnt, *c_useqcnt, *c_sseqcnt;
 138
 139         cond->busy = NULL;
 140         cond->c_seq[0] = 0;
 141         cond->c_seq[1] = 0;
 142         cond->c_seq[2] = 0;
 143         cond->unused = 0;
 144
 145         cond->misalign = (((uintptr_t)&cond->c_seq[0]) & 0x7) != 0;
 146         COND_GETSEQ_ADDR(cond, &c_lseqcnt, &c_useqcnt, &c_sseqcnt);
 147         *c_sseqcnt = PTH_RWS_CV_CBIT; // set Sword to 0c
 148
 149         if (conforming) {
 150                 if (attr) {
 151                         cond->pshared = attr->pshared;
 152                 } else {
 153                         cond->pshared = _PTHREAD_DEFAULT_PSHARED;
 154                 }
 155         } else {
 156                 cond->pshared = _PTHREAD_DEFAULT_PSHARED;
 157         }
 158
 159         // Ensure all contents are properly set before setting signature.
 160         OSMemoryBarrier();
 161         cond->sig = _PTHREAD_COND_SIG;
 162
 163         return 0;
 164 }
 165
 166 PTHREAD_NOINLINE
 167 static int
 168 _pthread_cond_check_init_slow(_pthread_cond *cond, bool *inited)
 169 {
 170         int res = EINVAL;
 171         if (cond->sig == _PTHREAD_COND_SIG_init) {
 172                 _PTHREAD_LOCK(cond->lock);
 173                 if (cond->sig == _PTHREAD_COND_SIG_init) {
 174                         res = _pthread_cond_init(cond, NULL, 0);
 175                         if (inited) {
 176                                 *inited = true;
 177                         }
 178                 } else if (cond->sig == _PTHREAD_COND_SIG) {
 179                         res = 0;
 180                 }
 181                 _PTHREAD_UNLOCK(cond->lock);
 182         } else if (cond->sig == _PTHREAD_COND_SIG) {
 183                 res = 0;
 184         }
 185         return res;
 186 }
 187
 188 static inline int
 189 _pthread_cond_check_init(_pthread_cond *cond, bool *inited)
 190 {
 191         int res = 0;
 192         if (cond->sig != _PTHREAD_COND_SIG) {
 193                 return _pthread_cond_check_init_slow(cond, inited);
 194         }
 195         return res;
 196 }
 197
 198 int
 199 pthread_cond_destroy(pthread_cond_t *ocond)
 200 {
 201         _pthread_cond *cond = (_pthread_cond *)ocond;
 202         int res = EINVAL;
 203         if (cond->sig == _PTHREAD_COND_SIG) {
 204                 _PTHREAD_LOCK(cond->lock);
 205
 206                 uint64_t oldval64, newval64;
 207                 uint32_t lcntval, ucntval, scntval;
 208                 volatile uint32_t *c_lseqcnt, *c_useqcnt, *c_sseqcnt;
 209
 210                 COND_GETSEQ_ADDR(cond, &c_lseqcnt, &c_useqcnt, &c_sseqcnt);
 211
 212                 do {
 213                         lcntval = *c_lseqcnt;
 214                         ucntval = *c_useqcnt;
 215                         scntval = *c_sseqcnt;
 216
 217                         // validate it is not busy
 218                         if ((lcntval & PTHRW_COUNT_MASK) != (scntval & PTHRW_COUNT_MASK)) {
 219                                 //res = EBUSY;
 220                                 break;
 221                         }
 222                         oldval64 = (((uint64_t)scntval) << 32);
 223                         oldval64 |= lcntval;
 224                         newval64 = oldval64;
 225                 } while (OSAtomicCompareAndSwap64Barrier(oldval64, newval64, (volatile int64_t *)c_lseqcnt) != TRUE);
 226
 227                 // <rdar://problem/13782056> Need to clear preposts.
 228                 uint32_t flags = 0;
 229                 bool needclearpre = ((scntval & PTH_RWS_CV_PBIT) != 0);
 230                 if (needclearpre && cond->pshared == PTHREAD_PROCESS_SHARED) {
 231                         flags |= _PTHREAD_MTX_OPT_PSHARED;
 232                 }
 233
 234                 cond->sig = _PTHREAD_NO_SIG;
 235                 res = 0;
 236
 237                 _PTHREAD_UNLOCK(cond->lock);
 238
 239                 if (needclearpre) {
 240                         (void)__psynch_cvclrprepost(cond, lcntval, ucntval, scntval, 0, lcntval, flags);
 241                 }
 242         } else if (cond->sig == _PTHREAD_COND_SIG_init) {
 243                 // Compatibility for misbehaving applications that attempt to
 244                 // destroy a statically initialized condition variable.
 245                 cond->sig = _PTHREAD_NO_SIG;
 246                 res = 0;
 247         }
 248         return res;
 249 }
 250
 251 static int
 252 _pthread_cond_signal(pthread_cond_t *ocond, bool broadcast, mach_port_t thread)
 253 {
 254         int res;
 255         _pthread_cond *cond = (_pthread_cond *)ocond;
 256
 257         uint32_t updateval;
 258         uint32_t diffgen;
 259         uint32_t ulval;
 260
 261         uint64_t oldval64, newval64;
 262         uint32_t lcntval, ucntval, scntval;
 263         volatile uint32_t *c_lseqcnt, *c_useqcnt, *c_sseqcnt;
 264
 265         int retry_count = 0, uretry_count = 0;
 266         int ucountreset = 0;
 267
 268         bool inited = false;
 269         res = _pthread_cond_check_init(cond, &inited);
 270         if (res != 0 || inited == true) {
 271                 return res;
 272         }
 273
 274         COND_GETSEQ_ADDR(cond, &c_lseqcnt, &c_useqcnt, &c_sseqcnt);
 275
 276         bool retry;
 277         do {
 278                 retry = false;
 279
 280                 lcntval = *c_lseqcnt;
 281                 ucntval = *c_useqcnt;
 282                 scntval = *c_sseqcnt;
 283
 284                 if (((lcntval & PTHRW_COUNT_MASK) == (scntval & PTHRW_COUNT_MASK)) ||
 285                     (thread == MACH_PORT_NULL && ((lcntval & PTHRW_COUNT_MASK) == (ucntval & PTHRW_COUNT_MASK)))) {
 286                         /* validate it is spurious and return */
 287                         oldval64 = (((uint64_t)scntval) << 32);
 288                         oldval64 |= lcntval;
 289                         newval64 = oldval64;
 290
 291                         if (OSAtomicCompareAndSwap64Barrier(oldval64, newval64, (volatile int64_t *)c_lseqcnt) != TRUE) {
 292                                 retry = true;
 293                                 continue;
 294                         } else {
 295                                 return 0;
 296                         }
 297                 }
 298
 299                 if (thread) {
 300                         break;
 301                 }
 302
 303                 /* validate to eliminate spurious values, race snapshots */
 304                 if (is_seqhigher((scntval & PTHRW_COUNT_MASK), (lcntval & PTHRW_COUNT_MASK))) {
 305                         /* since ucntval may be newer, just redo */
 306                         retry_count++;
 307                         if (retry_count > 8192) {
 308                                 return EAGAIN;
 309                         } else {
 310                                 sched_yield();
 311                                 retry = true;
 312                                 continue;
 313                         }
 314                 } else if (is_seqhigher((ucntval & PTHRW_COUNT_MASK), (lcntval & PTHRW_COUNT_MASK))) {
 315                         /* since ucntval may be newer, just redo */
 316                         uretry_count++;
 317                         if (uretry_count > 8192) {
 318                                 /*
 319                                  * U value if not used for a while can go out of sync
 320                                  * set this to S value and try one more time.
 321                                  */
 322                                 if (ucountreset != 0) {
 323                                         return EAGAIN;
 324                                 } else if (OSAtomicCompareAndSwap32Barrier(ucntval, (scntval & PTHRW_COUNT_MASK), (volatile int32_t *)c_useqcnt) == TRUE) {
 325                                         /* now the U is reset to S value */
 326                                         ucountreset = 1;
 327                                         uretry_count = 0;
 328                                 }
 329                         }
 330                         sched_yield();
 331                         retry = true;
 332                         continue;
 333                 }
 334
 335                 if (is_seqlower(ucntval & PTHRW_COUNT_MASK, scntval & PTHRW_COUNT_MASK) != 0) {
 336                         /* If U < S, set U = S+diff due to intr's TO, etc */
 337                         ulval = (scntval & PTHRW_COUNT_MASK);
 338                 } else {
 339                         /* If U >= S, set U = U+diff due to intr's TO, etc */
 340                         ulval = (ucntval & PTHRW_COUNT_MASK);
 341                 }
 342
 343                 if (broadcast) {
 344                         diffgen = diff_genseq(lcntval, ulval);
 345                         // Set U = L
 346                         ulval = (lcntval & PTHRW_COUNT_MASK);
 347                 } else {
 348                         ulval += PTHRW_INC;
 349                 }
 350
 351         } while (retry || OSAtomicCompareAndSwap32Barrier(ucntval, ulval, (volatile int32_t *)c_useqcnt) != TRUE);
 352
 353         uint32_t flags = 0;
 354         if (cond->pshared == PTHREAD_PROCESS_SHARED) {
 355                 flags |= _PTHREAD_MTX_OPT_PSHARED;
 356         }
 357
 358         uint64_t cvlsgen = ((uint64_t)scntval << 32) | lcntval;
 359
 360         if (broadcast) {
 361                 // pass old U val so kernel will know the diffgen
 362                 uint64_t cvudgen = ((uint64_t)ucntval << 32) | diffgen;
 363                 updateval = __psynch_cvbroad(ocond, cvlsgen, cvudgen, flags, NULL, 0, 0);
 364         } else {
 365                 updateval = __psynch_cvsignal(ocond, cvlsgen, ucntval, thread, NULL, 0, 0, flags);
 366         }
 367
 368         if (updateval != (uint32_t)-1 && updateval != 0) {
 369                 _pthread_cond_updateval(cond, 0, updateval);
 370         }
 371
 372         return 0;
 373 }
 374
 375
 376 /*
 377  * Signal a condition variable, waking up all threads waiting for it.
 378  */
 379 int
 380 pthread_cond_broadcast(pthread_cond_t *ocond)
 381 {
 382         return _pthread_cond_signal(ocond, true, MACH_PORT_NULL);
 383 }
 384
 385 /*
 386  * Signal a condition variable, waking a specified thread.
 387  */
 388 int
 389 pthread_cond_signal_thread_np(pthread_cond_t *ocond, pthread_t thread)
 390 {
 391         mach_port_t mp = MACH_PORT_NULL;
 392         if (thread) {
 393                 mp = pthread_mach_thread_np(thread);
 394         }
 395         return _pthread_cond_signal(ocond, false, mp);
 396 }
 397
 398 /*
 399  * Signal a condition variable, waking only one thread.
 400  */
 401 int
 402 pthread_cond_signal(pthread_cond_t *cond)
 403 {
 404         return pthread_cond_signal_thread_np(cond, NULL);
 405 }
 406
 407 /*
 408  * Manage a list of condition variables associated with a mutex
 409  */
 410
 411
 412 /*
 413  * Suspend waiting for a condition variable.
 414  * Note: we have to keep a list of condition variables which are using
 415  * this same mutex variable so we can detect invalid 'destroy' sequences.
 416  * If isconforming < 0, we skip the _pthread_testcancel(), but keep the
 417  * remaining conforming behavior..
 418  */
 419 __private_extern__ int
 420 _pthread_cond_wait(pthread_cond_t *ocond,
 421                         pthread_mutex_t *omutex,
 422                         const struct timespec *abstime,
 423                         int isRelative,
 424                         int isconforming)
 425 {
 426         int res;
 427         _pthread_cond *cond = (_pthread_cond *)ocond;
 428         _pthread_mutex *mutex = (_pthread_mutex *)omutex;
 429         struct timespec then = { 0, 0 };
 430         uint32_t mtxgen, mtxugen, flags=0, updateval;
 431         uint32_t lcntval, ucntval, scntval;
 432         uint32_t nlval, ulval, savebits;
 433         volatile uint32_t *c_lseqcnt, *c_useqcnt, *c_sseqcnt;
 434         uint64_t oldval64, newval64, mugen, cvlsgen;
 435         uint32_t *npmtx = NULL;
 436
 437 extern void _pthread_testcancel(pthread_t thread, int isconforming);
 438
 439         res = _pthread_cond_check_init(cond, NULL);
 440         if (res != 0) {
 441                 return res;
 442         }
 443
 444         if (isconforming) {
 445                 if (!_pthread_mutex_check_signature(mutex) &&
 446                                 !_pthread_mutex_check_signature_init(mutex)) {
 447                         return EINVAL;
 448                 }
 449                 if (isconforming > 0) {
 450                         _pthread_testcancel(pthread_self(), 1);
 451                 }
 452         }
 453
 454         /* send relative time to kernel */
 455         if (abstime) {
 456                 if (isRelative == 0) {
 457                         struct timespec now;
 458                         struct timeval tv;
 459                         __gettimeofday(&tv, NULL);
 460                         TIMEVAL_TO_TIMESPEC(&tv, &now);
 461
 462                         /* Compute relative time to sleep */
 463                         then.tv_nsec = abstime->tv_nsec - now.tv_nsec;
 464                         then.tv_sec = abstime->tv_sec - now.tv_sec;
 465                         if (then.tv_nsec < 0) {
 466                                 then.tv_nsec += NSEC_PER_SEC;
 467                                 then.tv_sec--;
 468                         }
 469                         if (then.tv_sec < 0 || (then.tv_sec == 0 && then.tv_nsec == 0)) {
 470                                 return ETIMEDOUT;
 471                         }
 472                         if (isconforming &&
 473                             (abstime->tv_sec < 0 ||
 474                              abstime->tv_nsec < 0 ||
 475                              abstime->tv_nsec >= NSEC_PER_SEC)) {
 476                                 return EINVAL;
 477                         }
 478                 } else {
 479                         then.tv_sec = abstime->tv_sec;
 480                         then.tv_nsec = abstime->tv_nsec;
 481                         if ((then.tv_sec == 0) && (then.tv_nsec == 0)) {
 482                                 return ETIMEDOUT;
 483                         }
 484                 }
 485                 if (isconforming && (then.tv_sec < 0 || then.tv_nsec < 0)) {
 486                         return EINVAL;
 487                 }
 488                 if (then.tv_nsec >= NSEC_PER_SEC) {
 489                         return EINVAL;
 490                 }
 491         }
 492
 493         if (cond->busy != NULL && cond->busy != mutex) {
 494                 return EINVAL;
 495         }
 496
 497         COND_GETSEQ_ADDR(cond, &c_lseqcnt, &c_useqcnt, &c_sseqcnt);
 498
 499         do {
 500                 lcntval = *c_lseqcnt;
 501                 ucntval = *c_useqcnt;
 502                 scntval = *c_sseqcnt;
 503
 504                 oldval64 = (((uint64_t)scntval) << 32);
 505                 oldval64 |= lcntval;
 506
 507                 /* remove c and p bits on S word */
 508                 savebits = scntval & PTH_RWS_CV_BITSALL;
 509                 ulval = (scntval & PTHRW_COUNT_MASK);
 510                 nlval = lcntval + PTHRW_INC;
 511                 newval64 = (((uint64_t)ulval) << 32);
 512                 newval64 |= nlval;
 513         } while (OSAtomicCompareAndSwap64Barrier(oldval64, newval64, (volatile int64_t *)c_lseqcnt) != TRUE);
 514
 515         cond->busy = mutex;
 516
 517         res = __mtx_droplock(mutex, &flags, &npmtx, &mtxgen, &mtxugen);
 518
 519         /* TBD: cases are for normal (non owner for recursive mutex; error checking)*/
 520         if (res != 0) {
 521                 return EINVAL;
 522         }
 523         if ((flags & _PTHREAD_MTX_OPT_NOTIFY) == 0) {
 524                 npmtx = NULL;
 525                 mugen = 0;
 526         } else {
 527                 mugen = ((uint64_t)mtxugen << 32) | mtxgen;
 528         }
 529         flags &= ~_PTHREAD_MTX_OPT_MUTEX;       /* reset the mutex bit as this is cvar */
 530
 531         cvlsgen = ((uint64_t)(ulval | savebits)<< 32) | nlval;
 532
 533         // SUSv3 requires pthread_cond_wait to be a cancellation point
 534         if (isconforming) {
 535                 pthread_cleanup_push(_pthread_cond_cleanup, (void *)cond);
 536                 updateval = __psynch_cvwait(ocond, cvlsgen, ucntval, (pthread_mutex_t *)npmtx, mugen, flags, (int64_t)then.tv_sec, (int32_t)then.tv_nsec);
 537                 _pthread_testcancel(pthread_self(), isconforming);
 538                 pthread_cleanup_pop(0);
 539         } else {
 540                 updateval = __psynch_cvwait(ocond, cvlsgen, ucntval, (pthread_mutex_t *)npmtx, mugen, flags, (int64_t)then.tv_sec, (int32_t)then.tv_nsec);
 541         }
 542
 543         if (updateval == (uint32_t)-1) {
 544                 int err = errno;
 545                 switch (err & 0xff) {
 546                         case ETIMEDOUT:
 547                                 res = ETIMEDOUT;
 548                                 break;
 549                         case EINTR:
 550                                 // spurious wakeup (unless canceled)
 551                                 res = 0;
 552                                 break;
 553                         default:
 554                                 res = EINVAL;
 555                                 break;
 556                 }
 557
 558                 // add unlock ref to show one less waiter
 559                 _pthread_cond_updateval(cond, err, 0);
 560         } else if (updateval != 0) {
 561                 // Successful wait
 562                 // The return due to prepost and might have bit states
 563                 // update S and return for prepo if needed
 564                 _pthread_cond_updateval(cond, 0, updateval);
 565         }
 566
 567         pthread_mutex_lock(omutex);
 568
 569         return res;
 570 }
 571
 572 static void
 573 _pthread_cond_cleanup(void *arg)
 574 {
 575         _pthread_cond *cond = (_pthread_cond *)arg;
 576         pthread_mutex_t *mutex;
 577
 578 // 4597450: begin
 579         pthread_t thread = pthread_self();
 580         int thcanceled = 0;
 581
 582         _PTHREAD_LOCK(thread->lock);
 583         thcanceled = (thread->detached & _PTHREAD_WASCANCEL);
 584         _PTHREAD_UNLOCK(thread->lock);
 585
 586         if (thcanceled == 0) {
 587                 return;
 588         }
 589
 590 // 4597450: end
 591         mutex = (pthread_mutex_t *)cond->busy;
 592
 593         // add unlock ref to show one less waiter
 594         _pthread_cond_updateval(cond, thread->cancel_error, 0);
 595
 596         /*
 597         ** Can't do anything if this fails -- we're on the way out
 598         */
 599         if (mutex != NULL) {
 600                 (void)pthread_mutex_lock(mutex);
 601         }
 602 }
 603
 604 #define ECVCERORR       256
 605 #define ECVPERORR       512
 606
 607 static void
 608 _pthread_cond_updateval(_pthread_cond *cond, int error, uint32_t updateval)
 609 {
 610         int needclearpre;
 611
 612         uint32_t diffgen, nsval;
 613         uint64_t oldval64, newval64;
 614         uint32_t lcntval, ucntval, scntval;
 615         volatile uint32_t *c_lseqcnt, *c_useqcnt, *c_sseqcnt;
 616
 617         if (error != 0) {
 618                 updateval = PTHRW_INC;
 619                 if ((error & ECVCERORR) != 0) {
 620                         updateval |= PTH_RWS_CV_CBIT;
 621                 }
 622                 if ((error & ECVPERORR) != 0) {
 623                         updateval |= PTH_RWS_CV_PBIT;
 624                 }
 625         }
 626
 627         COND_GETSEQ_ADDR(cond, &c_lseqcnt, &c_useqcnt, &c_sseqcnt);
 628
 629         do {
 630                 lcntval = *c_lseqcnt;
 631                 ucntval = *c_useqcnt;
 632                 scntval = *c_sseqcnt;
 633
 634                 diffgen = diff_genseq(lcntval, scntval); // pending waiters
 635
 636                 oldval64 = (((uint64_t)scntval) << 32);
 637                 oldval64 |= lcntval;
 638
 639                 if (diffgen <= 0) {
 640                         /* TBD: Assert, should not be the case */
 641                         /* validate it is spurious and return */
 642                         newval64 = oldval64;
 643                 } else {
 644                         // update S by one
 645
 646                         // update scntval with number of expected returns and bits
 647                         nsval = (scntval & PTHRW_COUNT_MASK) + (updateval & PTHRW_COUNT_MASK);
 648                         // set bits
 649                         nsval |= ((scntval & PTH_RWS_CV_BITSALL) | (updateval & PTH_RWS_CV_BITSALL));
 650
 651                         // if L==S and c&p bits are set, needs clearpre
 652                         if (((nsval & PTHRW_COUNT_MASK) == (lcntval & PTHRW_COUNT_MASK)) &&
 653                             ((nsval & PTH_RWS_CV_BITSALL) == PTH_RWS_CV_BITSALL)) {
 654                                 // reset p bit but retain c bit on the sword
 655                                 nsval &= PTH_RWS_CV_RESET_PBIT;
 656                                 needclearpre = 1;
 657                         } else {
 658                                 needclearpre = 0;
 659                         }
 660
 661                         newval64 = (((uint64_t)nsval) << 32);
 662                         newval64 |= lcntval;
 663                 }
 664         } while (OSAtomicCompareAndSwap64Barrier(oldval64, newval64, (volatile int64_t *)c_lseqcnt) != TRUE);
 665
 666         if (diffgen > 0) {
 667                 // if L == S, then reset associated mutex
 668                 if ((nsval & PTHRW_COUNT_MASK) == (lcntval & PTHRW_COUNT_MASK)) {
 669                         cond->busy = NULL;
 670                 }
 671
 672                 if (needclearpre != 0) {
 673                         uint32_t flags = 0;
 674                         if (cond->pshared == PTHREAD_PROCESS_SHARED) {
 675                                 flags |= _PTHREAD_MTX_OPT_PSHARED;
 676                         }
 677                         (void)__psynch_cvclrprepost(cond, lcntval, ucntval, nsval, 0, lcntval, flags);
 678                 }
 679         }
 680 }
 681
 682
 683 int
 684 pthread_cond_timedwait_relative_np(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime)
 685 {
 686         return _pthread_cond_wait(cond, mutex, abstime, 1, 0);
 687 }
 688
 689 #endif /* !BUILDING_VARIANT ] */
 690
 691 int
 692 pthread_cond_init(pthread_cond_t *ocond, const pthread_condattr_t *attr)
 693 {
 694         int conforming;
 695
 696 #if __DARWIN_UNIX03
 697         conforming = 1;
 698 #else /* __DARWIN_UNIX03 */
 699         conforming = 0;
 700 #endif /* __DARWIN_UNIX03 */
 701
 702         _pthread_cond *cond = (_pthread_cond *)ocond;
 703         _PTHREAD_LOCK_INIT(cond->lock);
 704         return _pthread_cond_init(cond, attr, conforming);
 705 }