thread.h

   1 /*    thread.h
   2  *
   3  *    Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
   4  *    by Larry Wall and others
   5  *
   6  *    You may distribute under the terms of either the GNU General Public
   7  *    License or the Artistic License, as specified in the README file.
   8  *
   9  */
  10
  11 #if defined(USE_ITHREADS)
  12
  13 #if defined(VMS)
  14 #include <builtins.h>
  15 #endif
  16
  17 #ifdef WIN32
  18 #  include <win32thread.h>
  19 #else
  20 #  ifdef OLD_PTHREADS_API /* Here be dragons. */
  21 #    define DETACH(t) \
  22     STMT_START {                                                \
  23         int _eC_;                                               \
  24         if ((_eC_ = pthread_detach(&(t)->self))) {              \
  25             MUTEX_UNLOCK(&(t)->mutex);                          \
  26             Perl_croak_nocontext("panic: DETACH (%d) [%s:%d]",  \
  27                                  _eC_, __FILE__, __LINE__);     \
  28         }                                                       \
  29     } STMT_END
  30
  31 #    define PERL_GET_CONTEXT    Perl_get_context()
  32 #    define PERL_SET_CONTEXT(t) Perl_set_context((void*)t)
  33
  34 #    define PTHREAD_GETSPECIFIC_INT
  35 #    ifdef OEMVS
  36 #      define pthread_addr_t void *
  37 #      define pthread_create(t,a,s,d)        pthread_create(t,&(a),s,d)
  38 #      define pthread_keycreate              pthread_key_create
  39 #    endif
  40 #    ifdef VMS
  41 #      define pthread_attr_init(a) pthread_attr_create(a)
  42 #      define PTHREAD_ATTR_SETDETACHSTATE(a,s) pthread_setdetach_np(a,s)
  43 #      define PTHREAD_CREATE(t,a,s,d) pthread_create(t,a,s,d)
  44 #      define pthread_key_create(k,d) pthread_keycreate(k,(pthread_destructor_t)(d))
  45 #      define pthread_mutexattr_init(a) pthread_mutexattr_create(a)
  46 #      define pthread_mutexattr_settype(a,t) pthread_mutexattr_setkind_np(a,t)
  47 #    endif
  48 #    if defined(__hpux) && defined(__ux_version) && __ux_version <= 1020
  49 #      define pthread_attr_init(a) pthread_attr_create(a)
  50        /* XXX pthread_setdetach_np() missing in DCE threads on HP-UX 10.20 */
  51 #      define PTHREAD_ATTR_SETDETACHSTATE(a,s)  (0)
  52 #      define PTHREAD_CREATE(t,a,s,d) pthread_create(t,a,s,d)
  53 #      define pthread_key_create(k,d) pthread_keycreate(k,(pthread_destructor_t)(d))
  54 #      define pthread_mutexattr_init(a) pthread_mutexattr_create(a)
  55 #      define pthread_mutexattr_settype(a,t) pthread_mutexattr_setkind_np(a,t)
  56 #    endif
  57 #    if defined(OEMVS)
  58 #      define PTHREAD_ATTR_SETDETACHSTATE(a,s) pthread_attr_setdetachstate(a,&(s))
  59 #      define YIELD pthread_yield(NULL)
  60 #    endif
  61 #  endif
  62 #  if !defined(__hpux) || !defined(__ux_version) || __ux_version > 1020
  63 #    define pthread_mutexattr_default NULL
  64 #    define pthread_condattr_default  NULL
  65 #  endif
  66 #endif
  67
  68 #ifndef PTHREAD_CREATE
  69 /* You are not supposed to pass NULL as the 2nd arg of PTHREAD_CREATE(). */
  70 #  define PTHREAD_CREATE(t,a,s,d) pthread_create(t,&(a),s,d)
  71 #endif
  72
  73 #ifndef PTHREAD_ATTR_SETDETACHSTATE
  74 #  define PTHREAD_ATTR_SETDETACHSTATE(a,s) pthread_attr_setdetachstate(a,s)
  75 #endif
  76
  77 #ifndef PTHREAD_CREATE_JOINABLE
  78 #  ifdef OLD_PTHREAD_CREATE_JOINABLE
  79 #    define PTHREAD_CREATE_JOINABLE OLD_PTHREAD_CREATE_JOINABLE
  80 #  else
  81 #    define PTHREAD_CREATE_JOINABLE 0 /* Panic?  No, guess. */
  82 #  endif
  83 #endif
  84
  85 #ifdef __VMS
  86   /* Default is 1024 on VAX, 8192 otherwise */
  87 #  ifdef __ia64
  88 #    define THREAD_CREATE_NEEDS_STACK (48*1024)
  89 #  else
  90 #    define THREAD_CREATE_NEEDS_STACK (32*1024)
  91 #  endif
  92 #endif
  93
  94 #ifdef I_MACH_CTHREADS
  95
  96 /* cthreads interface */
  97
  98 /* #include <mach/cthreads.h> is in perl.h #ifdef I_MACH_CTHREADS */
  99
 100 #define MUTEX_INIT(m) \
 101     STMT_START {                                                \
 102         *m = mutex_alloc();                                     \
 103         if (*m) {                                               \
 104             mutex_init(*m);                                     \
 105         } else {                                                \
 106             Perl_croak_nocontext("panic: MUTEX_INIT [%s:%d]",   \
 107                                  __FILE__, __LINE__);           \
 108         }                                                       \
 109     } STMT_END
 110
 111 #define MUTEX_LOCK(m)                   mutex_lock(*m)
 112 #define MUTEX_UNLOCK(m)                 mutex_unlock(*m)
 113 #define MUTEX_DESTROY(m) \
 114     STMT_START {                                                \
 115         mutex_free(*m);                                         \
 116         *m = 0;                                                 \
 117     } STMT_END
 118
 119 #define COND_INIT(c) \
 120     STMT_START {                                                \
 121         *c = condition_alloc();                                 \
 122         if (*c) {                                               \
 123             condition_init(*c);                                 \
 124         }                                                       \
 125         else {                                                  \
 126             Perl_croak_nocontext("panic: COND_INIT [%s:%d]",    \
 127                                  __FILE__, __LINE__);           \
 128         }                                                       \
 129     } STMT_END
 130
 131 #define COND_SIGNAL(c)          condition_signal(*c)
 132 #define COND_BROADCAST(c)       condition_broadcast(*c)
 133 #define COND_WAIT(c, m)         condition_wait(*c, *m)
 134 #define COND_DESTROY(c) \
 135     STMT_START {                                                \
 136         condition_free(*c);                                     \
 137         *c = 0;                                                 \
 138     } STMT_END
 139
 140 #define THREAD_RET_TYPE         any_t
 141
 142 #define DETACH(t)               cthread_detach(t->self)
 143 #define JOIN(t, avp)            (*(avp) = MUTABLE_AV(cthread_join(t->self)))
 144
 145 #define PERL_SET_CONTEXT(t)     cthread_set_data(cthread_self(), t)
 146 #define PERL_GET_CONTEXT        cthread_data(cthread_self())
 147
 148 #define INIT_THREADS            cthread_init()
 149 #define YIELD                   cthread_yield()
 150 #define ALLOC_THREAD_KEY        NOOP
 151 #define FREE_THREAD_KEY         NOOP
 152 #define SET_THREAD_SELF(thr)    (thr->self = cthread_self())
 153
 154 #endif /* I_MACH_CTHREADS */
 155
 156 #ifndef YIELD
 157 #  ifdef SCHED_YIELD
 158 #    define YIELD SCHED_YIELD
 159 #  elif defined(HAS_SCHED_YIELD)
 160 #    define YIELD sched_yield()
 161 #  elif defined(HAS_PTHREAD_YIELD)
 162     /* pthread_yield(NULL) platforms are expected
 163      * to have #defined YIELD for themselves. */
 164 #    define YIELD pthread_yield()
 165 #  endif
 166 #endif
 167
 168 #ifdef __hpux
 169 #  define MUTEX_INIT_NEEDS_MUTEX_ZEROED
 170 #endif
 171
 172 #ifndef MUTEX_INIT
 173
 174 #  ifdef MUTEX_INIT_NEEDS_MUTEX_ZEROED
 175     /* Temporary workaround, true bug is deeper. --jhi 1999-02-25 */
 176 #    define MUTEX_INIT(m) \
 177     STMT_START {                                                \
 178         int _eC_;                                               \
 179         Zero((m), 1, perl_mutex);                               \
 180         if ((_eC_ = pthread_mutex_init((m), pthread_mutexattr_default)))        \
 181             Perl_croak_nocontext("panic: MUTEX_INIT (%d) [%s:%d]",      \
 182                                  _eC_, __FILE__, __LINE__);     \
 183     } STMT_END
 184 #  else
 185 #    define MUTEX_INIT(m) \
 186     STMT_START {                                                \
 187         int _eC_;                                               \
 188         if ((_eC_ = pthread_mutex_init((m), pthread_mutexattr_default)))        \
 189             Perl_croak_nocontext("panic: MUTEX_INIT (%d) [%s:%d]",      \
 190                                  _eC_, __FILE__, __LINE__);     \
 191     } STMT_END
 192 #  endif
 193
 194 #  ifdef PERL_TSA_ACTIVE
 195 #    define perl_pthread_mutex_lock(m) perl_tsa_mutex_lock(m)
 196 #    define perl_pthread_mutex_unlock(m) perl_tsa_mutex_unlock(m)
 197 #  else
 198 #    define perl_pthread_mutex_lock(m) pthread_mutex_lock(m)
 199 #    define perl_pthread_mutex_unlock(m) pthread_mutex_unlock(m)
 200 #  endif
 201
 202 #  define MUTEX_LOCK(m) \
 203     STMT_START {                                                \
 204         int _eC_;                                               \
 205         if ((_eC_ = perl_pthread_mutex_lock((m))))                      \
 206             Perl_croak_nocontext("panic: MUTEX_LOCK (%d) [%s:%d]",      \
 207                                  _eC_, __FILE__, __LINE__);     \
 208     } STMT_END
 209
 210 #  define MUTEX_UNLOCK(m) \
 211     STMT_START {                                                \
 212         int _eC_;                                               \
 213         if ((_eC_ = perl_pthread_mutex_unlock((m))))                    \
 214             Perl_croak_nocontext("panic: MUTEX_UNLOCK (%d) [%s:%d]",    \
 215                                  _eC_, __FILE__, __LINE__);     \
 216     } STMT_END
 217
 218 #  define MUTEX_DESTROY(m) \
 219     STMT_START {                                                \
 220         int _eC_;                                               \
 221         if ((_eC_ = pthread_mutex_destroy((m))))                \
 222             Perl_croak_nocontext("panic: MUTEX_DESTROY (%d) [%s:%d]",   \
 223                                  _eC_, __FILE__, __LINE__);     \
 224     } STMT_END
 225 #endif /* MUTEX_INIT */
 226
 227 #ifndef COND_INIT
 228 #  define COND_INIT(c) \
 229     STMT_START {                                                \
 230         int _eC_;                                               \
 231         if ((_eC_ = pthread_cond_init((c), pthread_condattr_default)))  \
 232             Perl_croak_nocontext("panic: COND_INIT (%d) [%s:%d]",       \
 233                                  _eC_, __FILE__, __LINE__);     \
 234     } STMT_END
 235
 236 #  define COND_SIGNAL(c) \
 237     STMT_START {                                                \
 238         int _eC_;                                               \
 239         if ((_eC_ = pthread_cond_signal((c))))                  \
 240             Perl_croak_nocontext("panic: COND_SIGNAL (%d) [%s:%d]",     \
 241                                  _eC_, __FILE__, __LINE__);     \
 242     } STMT_END
 243
 244 #  define COND_BROADCAST(c) \
 245     STMT_START {                                                \
 246         int _eC_;                                               \
 247         if ((_eC_ = pthread_cond_broadcast((c))))               \
 248             Perl_croak_nocontext("panic: COND_BROADCAST (%d) [%s:%d]",  \
 249                                  _eC_, __FILE__, __LINE__);     \
 250     } STMT_END
 251
 252 #  define COND_WAIT(c, m) \
 253     STMT_START {                                                \
 254         int _eC_;                                               \
 255         if ((_eC_ = pthread_cond_wait((c), (m))))               \
 256             Perl_croak_nocontext("panic: COND_WAIT (%d) [%s:%d]",       \
 257                                  _eC_, __FILE__, __LINE__);     \
 258     } STMT_END
 259
 260 #  define COND_DESTROY(c) \
 261     STMT_START {                                                \
 262         int _eC_;                                               \
 263         if ((_eC_ = pthread_cond_destroy((c))))                 \
 264             Perl_croak_nocontext("panic: COND_DESTROY (%d) [%s:%d]",    \
 265                                  _eC_, __FILE__, __LINE__);     \
 266     } STMT_END
 267 #endif /* COND_INIT */
 268
 269 #if defined(MUTEX_LOCK) && defined(MUTEX_UNLOCK)                \
 270  && defined(COND_SIGNAL) && defined(COND_WAIT)
 271
 272 /* These emulate native many-reader/1-writer locks.
 273  * Basically a locking reader just locks the semaphore long enough to increment
 274  * a counter; and similarly decrements it when when through.  Any writer will
 275  * run only when the count of readers is 0.  That is because it blocks on that
 276  * semaphore (doing a COND_WAIT) until it gets control of it, which won't
 277  * happen unless the count becomes 0.  ALL readers and other writers are then
 278  * blocked until it releases the semaphore.  The reader whose unlocking causes
 279  * the count to become 0 signals any waiting writers, and the system guarantees
 280  * that only one gets control at a time */
 281
 282 #  define PERL_READ_LOCK(mutex)                                     \
 283     STMT_START {                                                    \
 284         MUTEX_LOCK(&(mutex)->lock);                                 \
 285         (mutex)->readers_count++;                                   \
 286         MUTEX_UNLOCK(&(mutex)->lock);                               \
 287     } STMT_END
 288
 289 #  define PERL_READ_UNLOCK(mutex)                                   \
 290     STMT_START {                                                    \
 291         MUTEX_LOCK(&(mutex)->lock);                                 \
 292         (mutex)->readers_count--;                                   \
 293         if ((mutex)->readers_count <= 0) {                          \
 294             assert((mutex)->readers_count == 0);                    \
 295             COND_SIGNAL(&(mutex)->wakeup);                          \
 296             (mutex)->readers_count = 0;                             \
 297         }                                                           \
 298         MUTEX_UNLOCK(&(mutex)->lock);                               \
 299     } STMT_END
 300
 301 #  define PERL_WRITE_LOCK(mutex)                                    \
 302     STMT_START {                                                    \
 303         MUTEX_LOCK(&(mutex)->lock);                                 \
 304         do {                                                        \
 305             if ((mutex)->readers_count <= 0) {                      \
 306                 assert((mutex)->readers_count == 0);                \
 307                 (mutex)->readers_count = 0;                         \
 308                 break;                                              \
 309             }                                                       \
 310             COND_WAIT(&(mutex)->wakeup, &(mutex)->lock);            \
 311         }                                                           \
 312         while (1);                                                  \
 313                                                                     \
 314         /* Here, the mutex is locked, with no readers */            \
 315     } STMT_END
 316
 317 #  define PERL_WRITE_UNLOCK(mutex)                                  \
 318     STMT_START {                                                    \
 319         COND_SIGNAL(&(mutex)->wakeup);                              \
 320         MUTEX_UNLOCK(&(mutex)->lock);                               \
 321     } STMT_END
 322
 323 #  define PERL_RW_MUTEX_INIT(mutex)                                 \
 324     STMT_START {                                                    \
 325         MUTEX_INIT(&(mutex)->lock);                                 \
 326         COND_INIT(&(mutex)->wakeup);                                \
 327         (mutex)->readers_count = 0;                                 \
 328     } STMT_END
 329
 330 #  define PERL_RW_MUTEX_DESTROY(mutex)                              \
 331     STMT_START {                                                    \
 332         COND_DESTROY(&(mutex)->wakeup);                             \
 333         MUTEX_DESTROY(&(mutex)->lock);                              \
 334     } STMT_END
 335
 336 #endif
 337
 338 /* DETACH(t) must only be called while holding t->mutex */
 339 #ifndef DETACH
 340 #  define DETACH(t) \
 341     STMT_START {                                                \
 342         int _eC_;                                               \
 343         if ((_eC_ = pthread_detach((t)->self))) {               \
 344             MUTEX_UNLOCK(&(t)->mutex);                          \
 345             Perl_croak_nocontext("panic: DETACH (%d) [%s:%d]",  \
 346                                  _eC_, __FILE__, __LINE__);     \
 347         }                                                       \
 348     } STMT_END
 349 #endif /* DETACH */
 350
 351 #ifndef JOIN
 352 #  define JOIN(t, avp) \
 353     STMT_START {                                                \
 354         int _eC_;                                               \
 355         if ((_eC_ = pthread_join((t)->self, (void**)(avp))))    \
 356             Perl_croak_nocontext("panic: pthread_join (%d) [%s:%d]",    \
 357                                  _eC_, __FILE__, __LINE__);     \
 358     } STMT_END
 359 #endif /* JOIN */
 360
 361 /* Use an unchecked fetch of thread-specific data instead of a checked one.
 362  * It would fail if the key were bogus, but if the key were bogus then
 363  * Really Bad Things would be happening anyway. --dan */
 364 #if (defined(__ALPHA) && (__VMS_VER >= 70000000)) || \
 365     (defined(__alpha) && defined(__osf__) && !defined(__GNUC__)) /* Available only on >= 4.0 */
 366 #  define HAS_PTHREAD_UNCHECKED_GETSPECIFIC_NP /* Configure test needed */
 367 #endif
 368
 369 #ifdef HAS_PTHREAD_UNCHECKED_GETSPECIFIC_NP
 370 #  define PTHREAD_GETSPECIFIC(key) pthread_unchecked_getspecific_np(key)
 371 #else
 372 #    define PTHREAD_GETSPECIFIC(key) pthread_getspecific(key)
 373 #endif
 374
 375 #if defined(PERL_THREAD_LOCAL) && !defined(PERL_GET_CONTEXT) && !defined(PERL_SET_CONTEXT) && !defined(__cplusplus)
 376 /* Use C11 thread-local storage, where possible.
 377  * Frustratingly we can't use it for C++ extensions, C++ and C disagree on the
 378  * syntax used for thread local storage, meaning that the working token that
 379  * Configure probed for C turns out to be a compiler error on C++. Great.
 380  * (Well, unless one or both is supporting non-standard syntax as an extension)
 381  * As Configure doesn't have a way to probe for C++ dialects, we just take the
 382  * safe option and do the same as 5.34.0 and earlier - use pthreads on C++.
 383  * Of course, if C++ XS extensions really want to avoid *all* this overhead,
 384  * they should #define PERL_NO_GET_CONTEXT and pass aTHX/aTHX_ explicitly) */
 385 #  define PERL_USE_THREAD_LOCAL
 386 extern PERL_THREAD_LOCAL void *PL_current_context;
 387
 388 #  define PERL_GET_CONTEXT        PL_current_context
 389
 390 /* We must also call pthread_setspecific() always, as C++ code has to read it
 391  * with pthreads (the #else side just below) */
 392
 393 #  define PERL_SET_CONTEXT(t)                                           \
 394     STMT_START {                                                        \
 395         int _eC_;                                                       \
 396         if ((_eC_ = pthread_setspecific(PL_thr_key, PL_current_context = (void *)(t)))) \
 397             Perl_croak_nocontext("panic: pthread_setspecific (%d) [%s:%d]", \
 398                                  _eC_, __FILE__, __LINE__);             \
 399     } STMT_END
 400
 401 #else
 402 /* else fall back to pthreads */
 403
 404 #  ifndef PERL_GET_CONTEXT
 405 #    define PERL_GET_CONTEXT    PTHREAD_GETSPECIFIC(PL_thr_key)
 406 #  endif
 407
 408 /* For C++ extensions built on a system where the C compiler provides thread
 409  * local storage that call PERL_SET_CONTEXT() also need to set
 410  * PL_current_context, so need to call into C code to do this.
 411  * To avoid exploding code complexity, do this also on C platforms that don't
 412  * support thread local storage. PERL_SET_CONTEXT is not called that often. */
 413
 414 #  ifndef PERL_SET_CONTEXT
 415 #    define PERL_SET_CONTEXT(t) Perl_set_context((void*)t)
 416 #  endif /* PERL_SET_CONTEXT */
 417 #endif /* PERL_THREAD_LOCAL */
 418
 419 #ifndef INIT_THREADS
 420 #  ifdef NEED_PTHREAD_INIT
 421 #    define INIT_THREADS pthread_init()
 422 #  endif
 423 #endif
 424
 425 #ifndef ALLOC_THREAD_KEY
 426 #  define ALLOC_THREAD_KEY \
 427     STMT_START {                                                \
 428         if (pthread_key_create(&PL_thr_key, 0)) {               \
 429             PERL_UNUSED_RESULT(write(2, STR_WITH_LEN("panic: pthread_key_create failed\n"))); \
 430             exit(1);                                            \
 431         }                                                       \
 432     } STMT_END
 433 #endif
 434
 435 #ifndef FREE_THREAD_KEY
 436 #  define FREE_THREAD_KEY \
 437     STMT_START {                                                \
 438         pthread_key_delete(PL_thr_key);                         \
 439     } STMT_END
 440 #endif
 441
 442 #ifndef PTHREAD_ATFORK
 443 #  ifdef HAS_PTHREAD_ATFORK
 444 #    define PTHREAD_ATFORK(prepare,parent,child)                \
 445         pthread_atfork(prepare,parent,child)
 446 #  else
 447 #    define PTHREAD_ATFORK(prepare,parent,child)                \
 448         NOOP
 449 #  endif
 450 #endif
 451
 452 #ifndef THREAD_RET_TYPE
 453 #  define THREAD_RET_TYPE       void *
 454 #endif /* THREAD_RET */
 455
 456 #  define LOCK_DOLLARZERO_MUTEX         MUTEX_LOCK(&PL_dollarzero_mutex)
 457 #  define UNLOCK_DOLLARZERO_MUTEX       MUTEX_UNLOCK(&PL_dollarzero_mutex)
 458
 459 #endif /* USE_ITHREADS */
 460
 461 #ifndef MUTEX_LOCK
 462 #  define MUTEX_LOCK(m)           NOOP
 463 #endif
 464
 465 #ifndef MUTEX_UNLOCK
 466 #  define MUTEX_UNLOCK(m)         NOOP
 467 #endif
 468
 469 #ifndef MUTEX_INIT
 470 #  define MUTEX_INIT(m)           NOOP
 471 #endif
 472
 473 #ifndef MUTEX_DESTROY
 474 #  define MUTEX_DESTROY(m)        NOOP
 475 #endif
 476
 477 #ifndef COND_INIT
 478 #  define COND_INIT(c)            NOOP
 479 #endif
 480
 481 #ifndef COND_SIGNAL
 482 #  define COND_SIGNAL(c)          NOOP
 483 #endif
 484
 485 #ifndef COND_BROADCAST
 486 #  define COND_BROADCAST(c)       NOOP
 487 #endif
 488
 489 #ifndef COND_WAIT
 490 #  define COND_WAIT(c, m)         NOOP
 491 #endif
 492
 493 #ifndef COND_DESTROY
 494 #  define COND_DESTROY(c)         NOOP
 495 #endif
 496
 497 #ifndef PERL_READ_LOCK
 498 #  define PERL_READ_LOCK          NOOP
 499 #  define PERL_READ_UNLOCK        NOOP
 500 #  define PERL_WRITE_LOCK         NOOP
 501 #  define PERL_WRITE_UNLOCK       NOOP
 502 #  define PERL_RW_MUTEX_INIT      NOOP
 503 #  define PERL_RW_MUTEX_DESTROY   NOOP
 504 #endif
 505
 506 #ifndef LOCK_DOLLARZERO_MUTEX
 507 #  define LOCK_DOLLARZERO_MUTEX   NOOP
 508 #endif
 509
 510 #ifndef UNLOCK_DOLLARZERO_MUTEX
 511 #  define UNLOCK_DOLLARZERO_MUTEX NOOP
 512 #endif
 513
 514 /* THR, SET_THR, and dTHR are there for compatibility with old versions */
 515 #ifndef THR
 516 #  define THR           PERL_GET_THX
 517 #endif
 518
 519 #ifndef SET_THR
 520 #  define SET_THR(t)    PERL_SET_THX(t)
 521 #endif
 522
 523 #ifndef dTHR
 524 #  define dTHR dNOOP
 525 #endif
 526
 527 #ifndef INIT_THREADS
 528 #  define INIT_THREADS NOOP
 529 #endif
 530
 531 /*
 532  * ex: set ts=8 sts=4 sw=4 et:
 533  */