/* Thread package. This is intended to be usable independently from Python. The implementation for system foobar is in a file thread_foobar.h which is included by this file dependent on config settings. Stuff shared by all thread_*.h files is collected here. */ #include "Python.h" #ifndef _POSIX_THREADS /* This means pthreads are not implemented in libc headers, hence the macro not present in unistd.h. But they still can be implemented as an external library (e.g. gnu pth in pthread emulation) */ # ifdef HAVE_PTHREAD_H # include /* _POSIX_THREADS */ # endif #endif #ifndef DONT_HAVE_STDIO_H #include #endif #include #include "pythread.h" #ifndef _POSIX_THREADS #ifdef __sgi #define SGI_THREADS #endif #ifdef HAVE_THREAD_H #define SOLARIS_THREADS #endif #if defined(sun) && !defined(SOLARIS_THREADS) #define SUN_LWP #endif /* Check if we're running on HP-UX and _SC_THREADS is defined. If so, then enough of the Posix threads package is implemented to support python threads. This is valid for HP-UX 11.23 running on an ia64 system. If needed, add a check of __ia64 to verify that we're running on a ia64 system instead of a pa-risc system. */ #ifdef __hpux #ifdef _SC_THREADS #define _POSIX_THREADS #endif #endif #endif /* _POSIX_THREADS */ #ifdef Py_DEBUG static int thread_debug = 0; #define dprintf(args) (void)((thread_debug & 1) && printf args) #define d2printf(args) ((thread_debug & 8) && printf args) #else #define dprintf(args) #define d2printf(args) #endif static int initialized; static void PyThread__init_thread(void); /* Forward */ void PyThread_init_thread(void) { #ifdef Py_DEBUG char *p = Py_GETENV("PYTHONTHREADDEBUG"); if (p) { if (*p) thread_debug = atoi(p); else thread_debug = 1; } #endif /* Py_DEBUG */ if (initialized) return; initialized = 1; dprintf(("PyThread_init_thread called\n")); PyThread__init_thread(); } /* Support for runtime thread stack size tuning. A value of 0 means using the platform's default stack size or the size specified by the THREAD_STACK_SIZE macro. */ static size_t _pythread_stacksize = 0; #ifdef SGI_THREADS #error SGI Irix threads are now unsupported, and code will be removed in 3.3. #include "thread_sgi.h" #endif #ifdef SOLARIS_THREADS #define PYTHREAD_NAME "solaris" #include "thread_solaris.h" #endif #ifdef SUN_LWP #error SunOS lightweight processes are now unsupported, and code will be removed in 3.3. #include "thread_lwp.h" #endif #ifdef HAVE_PTH #error GNU pth threads are now unsupported, and code will be removed in 3.3. #include "thread_pth.h" #undef _POSIX_THREADS #endif #ifdef _POSIX_THREADS #define PYTHREAD_NAME "pthread" #include "thread_pthread.h" #endif #ifdef C_THREADS #error Mach C Threads are now unsupported, and code will be removed in 3.3. #include "thread_cthread.h" #endif #ifdef NT_THREADS #define PYTHREAD_NAME "nt" #include "thread_nt.h" #endif #ifdef OS2_THREADS #define PYTHREAD_NAME "os2" #include "thread_os2.h" #endif #ifdef PLAN9_THREADS #define PYTHREAD_NAME "plan9" #include "thread_plan9.h" #endif /* #ifdef FOOBAR_THREADS #include "thread_foobar.h" #endif */ /* return the current thread stack size */ size_t PyThread_get_stacksize(void) { return _pythread_stacksize; } /* Only platforms defining a THREAD_SET_STACKSIZE() macro in thread_.h support changing the stack size. Return 0 if stack size is valid, -1 if stack size value is invalid, -2 if setting stack size is not supported. */ int PyThread_set_stacksize(size_t size) { #if defined(THREAD_SET_STACKSIZE) return THREAD_SET_STACKSIZE(size); #else return -2; #endif } #ifndef Py_HAVE_NATIVE_TLS /* If the platform has not supplied a platform specific TLS implementation, provide our own. This code stolen from "thread_sgi.h", where it was the only implementation of an existing Python TLS API. */ /* ------------------------------------------------------------------------ Per-thread data ("key") support. Use PyThread_create_key() to create a new key. This is typically shared across threads. Use PyThread_set_key_value(thekey, value) to associate void* value with thekey in the current thread. Each thread has a distinct mapping of thekey to a void* value. Caution: if the current thread already has a mapping for thekey, value is ignored. Use PyThread_get_key_value(thekey) to retrieve the void* value associated with thekey in the current thread. This returns NULL if no value is associated with thekey in the current thread. Use PyThread_delete_key_value(thekey) to forget the current thread's associated value for thekey. PyThread_delete_key(thekey) forgets the values associated with thekey across *all* threads. While some of these functions have error-return values, none set any Python exception. None of the functions does memory management on behalf of the void* values. You need to allocate and deallocate them yourself. If the void* values happen to be PyObject*, these functions don't do refcount operations on them either. The GIL does not need to be held when calling these functions; they supply their own locking. This isn't true of PyThread_create_key(), though (see next paragraph). There's a hidden assumption that PyThread_create_key() will be called before any of the other functions are called. There's also a hidden assumption that calls to PyThread_create_key() are serialized externally. ------------------------------------------------------------------------ */ /* A singly-linked list of struct key objects remembers all the key->value * associations. File static keyhead heads the list. keymutex is used * to enforce exclusion internally. */ struct key { /* Next record in the list, or NULL if this is the last record. */ struct key *next; /* The thread id, according to PyThread_get_thread_ident(). */ long id; /* The key and its associated value. */ int key; void *value; }; static struct key *keyhead = NULL; static PyThread_type_lock keymutex = NULL; static int nkeys = 0; /* PyThread_create_key() hands out nkeys+1 next */ /* Internal helper. * If the current thread has a mapping for key, the appropriate struct key* * is returned. NB: value is ignored in this case! * If there is no mapping for key in the current thread, then: * If value is NULL, NULL is returned. * Else a mapping of key to value is created for the current thread, * and a pointer to a new struct key* is returned; except that if * malloc() can't find room for a new struct key*, NULL is returned. * So when value==NULL, this acts like a pure lookup routine, and when * value!=NULL, this acts like dict.setdefault(), returning an existing * mapping if one exists, else creating a new mapping. * * Caution: this used to be too clever, trying to hold keymutex only * around the "p->next = keyhead; keyhead = p" pair. That allowed * another thread to mutate the list, via key deletion, concurrent with * find_key() crawling over the list. Hilarity ensued. For example, when * the for-loop here does "p = p->next", p could end up pointing at a * record that PyThread_delete_key_value() was concurrently free()'ing. * That could lead to anything, from failing to find a key that exists, to * segfaults. Now we lock the whole routine. */ static struct key * find_key(int key, void *value) { struct key *p, *prev_p; long id = PyThread_get_thread_ident(); if (!keymutex) return NULL; PyThread_acquire_lock(keymutex, 1); prev_p = NULL; for (p = keyhead; p != NULL; p = p->next) { if (p->id == id && p->key == key) goto Done; /* Sanity check. These states should never happen but if * they do we must abort. Otherwise we'll end up spinning in * in a tight loop with the lock held. A similar check is done * in pystate.c tstate_delete_common(). */ if (p == prev_p) Py_FatalError("tls find_key: small circular list(!)"); prev_p = p; if (p->next == keyhead) Py_FatalError("tls find_key: circular list(!)"); } if (value == NULL) { assert(p == NULL); goto Done; } p = (struct key *)malloc(sizeof(struct key)); if (p != NULL) { p->id = id; p->key = key; p->value = value; p->next = keyhead; keyhead = p; } Done: PyThread_release_lock(keymutex); return p; } /* Return a new key. This must be called before any other functions in * this family, and callers must arrange to serialize calls to this * function. No violations are detected. */ int PyThread_create_key(void) { /* All parts of this function are wrong if it's called by multiple * threads simultaneously. */ if (keymutex == NULL) keymutex = PyThread_allocate_lock(); return ++nkeys; } /* Forget the associations for key across *all* threads. */ void PyThread_delete_key(int key) { struct key *p, **q; PyThread_acquire_lock(keymutex, 1); q = &keyhead; while ((p = *q) != NULL) { if (p->key == key) { *q = p->next; free((void *)p); /* NB This does *not* free p->value! */ } else q = &p->next; } PyThread_release_lock(keymutex); } /* Confusing: If the current thread has an association for key, * value is ignored, and 0 is returned. Else an attempt is made to create * an association of key to value for the current thread. 0 is returned * if that succeeds, but -1 is returned if there's not enough memory * to create the association. value must not be NULL. */ int PyThread_set_key_value(int key, void *value) { struct key *p; assert(value != NULL); p = find_key(key, value); if (p == NULL) return -1; else return 0; } /* Retrieve the value associated with key in the current thread, or NULL * if the current thread doesn't have an association for key. */ void * PyThread_get_key_value(int key) { struct key *p = find_key(key, NULL); if (p == NULL) return NULL; else return p->value; } /* Forget the current thread's association for key, if any. */ void PyThread_delete_key_value(int key) { long id = PyThread_get_thread_ident(); struct key *p, **q; PyThread_acquire_lock(keymutex, 1); q = &keyhead; while ((p = *q) != NULL) { if (p->key == key && p->id == id) { *q = p->next; free((void *)p); /* NB This does *not* free p->value! */ break; } else q = &p->next; } PyThread_release_lock(keymutex); } /* Forget everything not associated with the current thread id. * This function is called from PyOS_AfterFork(). It is necessary * because other thread ids which were in use at the time of the fork * may be reused for new threads created in the forked process. */ void PyThread_ReInitTLS(void) { long id = PyThread_get_thread_ident(); struct key *p, **q; if (!keymutex) return; /* As with interpreter_lock in PyEval_ReInitThreads() we just create a new lock without freeing the old one */ keymutex = PyThread_allocate_lock(); /* Delete all keys which do not match the current thread id */ q = &keyhead; while ((p = *q) != NULL) { if (p->id != id) { *q = p->next; free((void *)p); /* NB This does *not* free p->value! */ } else q = &p->next; } } #endif /* Py_HAVE_NATIVE_TLS */ PyDoc_STRVAR(threadinfo__doc__, "sys.thread_info\n\ \n\ A struct sequence holding information about the thread implementation."); static PyStructSequence_Field threadinfo_fields[] = { {"name", "name of the thread implementation"}, {"lock", "name of the lock implementation"}, {"version", "name and version of the thread library"}, {0} }; static PyStructSequence_Desc threadinfo_desc = { "sys.thread_info", /* name */ threadinfo__doc__, /* doc */ threadinfo_fields, /* fields */ 3 }; static PyTypeObject ThreadInfoType; PyObject* PyThread_GetInfo(void) { PyObject *threadinfo, *value; int pos = 0; #if (defined(_POSIX_THREADS) && defined(HAVE_CONFSTR) \ && defined(_CS_GNU_LIBPTHREAD_VERSION)) char buffer[255]; int len; #endif if (ThreadInfoType.tp_name == 0) PyStructSequence_InitType(&ThreadInfoType, &threadinfo_desc); threadinfo = PyStructSequence_New(&ThreadInfoType); if (threadinfo == NULL) return NULL; value = PyUnicode_FromString(PYTHREAD_NAME); if (value == NULL) { Py_DECREF(threadinfo); return NULL; } PyStructSequence_SET_ITEM(threadinfo, pos++, value); #ifdef _POSIX_THREADS #ifdef USE_SEMAPHORES value = PyUnicode_FromString("semaphore"); #else value = PyUnicode_FromString("mutex+cond"); #endif if (value == NULL) { Py_DECREF(threadinfo); return NULL; } #else Py_INCREF(Py_None); value = Py_None; #endif PyStructSequence_SET_ITEM(threadinfo, pos++, value); #if (defined(_POSIX_THREADS) && defined(HAVE_CONFSTR) \ && defined(_CS_GNU_LIBPTHREAD_VERSION)) value = NULL; len = confstr(_CS_GNU_LIBPTHREAD_VERSION, buffer, sizeof(buffer)); if (1 < len && len < sizeof(buffer)) { value = PyUnicode_DecodeFSDefaultAndSize(buffer, len-1); if (value == NULL) PyErr_Clear(); } if (value == NULL) #endif { Py_INCREF(Py_None); value = Py_None; } PyStructSequence_SET_ITEM(threadinfo, pos++, value); return threadinfo; } 0 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626


/* Posix threads interface */

#include <stdlib.h>
#include <string.h>
#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)
#define destructor xxdestructor
#endif
#include <pthread.h>
#if defined(__APPLE__) || defined(HAVE_PTHREAD_DESTRUCTOR)
#undef destructor
#endif
#include <signal.h>

/* The POSIX spec requires that use of pthread_attr_setstacksize
   be conditional on _POSIX_THREAD_ATTR_STACKSIZE being defined. */
#ifdef _POSIX_THREAD_ATTR_STACKSIZE
#ifndef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE       0       /* use default stack size */
#endif
/* for safety, ensure a viable minimum stacksize */
#define THREAD_STACK_MIN        0x8000  /* 32kB */
#else  /* !_POSIX_THREAD_ATTR_STACKSIZE */
#ifdef THREAD_STACK_SIZE
#error "THREAD_STACK_SIZE defined but _POSIX_THREAD_ATTR_STACKSIZE undefined"
#endif
#endif

/* The POSIX spec says that implementations supporting the sem_*
   family of functions must indicate this by defining
   _POSIX_SEMAPHORES. */
#ifdef _POSIX_SEMAPHORES
/* On FreeBSD 4.x, _POSIX_SEMAPHORES is defined empty, so
   we need to add 0 to make it work there as well. */
#if (_POSIX_SEMAPHORES+0) == -1
#define HAVE_BROKEN_POSIX_SEMAPHORES
#else
#include <semaphore.h>
#include <errno.h>
#endif
#endif

/* Before FreeBSD 5.4, system scope threads was very limited resource
   in default setting.  So the process scope is preferred to get
   enough number of threads to work. */
#ifdef __FreeBSD__
#include <osreldate.h>
#if __FreeBSD_version >= 500000 && __FreeBSD_version < 504101
#undef PTHREAD_SYSTEM_SCHED_SUPPORTED
#endif
#endif

#if !defined(pthread_attr_default)
#  define pthread_attr_default ((pthread_attr_t *)NULL)
#endif
#if !defined(pthread_mutexattr_default)
#  define pthread_mutexattr_default ((pthread_mutexattr_t *)NULL)
#endif
#if !defined(pthread_condattr_default)
#  define pthread_condattr_default ((pthread_condattr_t *)NULL)
#endif


/* Whether or not to use semaphores directly rather than emulating them with
 * mutexes and condition variables:
 */
#if (defined(_POSIX_SEMAPHORES) && !defined(HAVE_BROKEN_POSIX_SEMAPHORES) && \
     defined(HAVE_SEM_TIMEDWAIT))
#  define USE_SEMAPHORES
#else
#  undef USE_SEMAPHORES
#endif


/* On platforms that don't use standard POSIX threads pthread_sigmask()
 * isn't present.  DEC threads uses sigprocmask() instead as do most
 * other UNIX International compliant systems that don't have the full
 * pthread implementation.
 */
#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK)
#  define SET_THREAD_SIGMASK pthread_sigmask
#else
#  define SET_THREAD_SIGMASK sigprocmask
#endif


/* We assume all modern POSIX systems have gettimeofday() */
#ifdef GETTIMEOFDAY_NO_TZ
#define GETTIMEOFDAY(ptv) gettimeofday(ptv)
#else
#define GETTIMEOFDAY(ptv) gettimeofday(ptv, (struct timezone *)NULL)
#endif

#define MICROSECONDS_TO_TIMESPEC(microseconds, ts) \
do { \
    struct timeval tv; \
    GETTIMEOFDAY(&tv); \
    tv.tv_usec += microseconds % 1000000; \
    tv.tv_sec += microseconds / 1000000; \
    tv.tv_sec += tv.tv_usec / 1000000; \
    tv.tv_usec %= 1000000; \
    ts.tv_sec = tv.tv_sec; \
    ts.tv_nsec = tv.tv_usec * 1000; \
} while(0)


/* A pthread mutex isn't sufficient to model the Python lock type
 * because, according to Draft 5 of the docs (P1003.4a/D5), both of the
 * following are undefined:
 *  -> a thread tries to lock a mutex it already has locked
 *  -> a thread tries to unlock a mutex locked by a different thread
 * pthread mutexes are designed for serializing threads over short pieces
 * of code anyway, so wouldn't be an appropriate implementation of
 * Python's locks regardless.
 *
 * The pthread_lock struct implements a Python lock as a "locked?" bit
 * and a <condition, mutex> pair.  In general, if the bit can be acquired
 * instantly, it is, else the pair is used to block the thread until the
 * bit is cleared.     9 May 1994 tim@ksr.com
 */

typedef struct {
    char             locked; /* 0=unlocked, 1=locked */
    /* a <cond, mutex> pair to handle an acquire of a locked lock */
    pthread_cond_t   lock_released;
    pthread_mutex_t  mut;
} pthread_lock;

#define CHECK_STATUS(name)  if (status != 0) { perror(name); error = 1; }

/*
 * Initialization.
 */

#ifdef _HAVE_BSDI
static
void _noop(void)
{
}

static void
PyThread__init_thread(void)
{
    /* DO AN INIT BY STARTING THE THREAD */
    static int dummy = 0;
    pthread_t thread1;
    pthread_create(&thread1, NULL, (void *) _noop, &dummy);
    pthread_join(thread1, NULL);
}

#else /* !_HAVE_BSDI */

static void
PyThread__init_thread(void)
{
#if defined(_AIX) && defined(__GNUC__)
    pthread_init();
#endif
}

#endif /* !_HAVE_BSDI */

/*
 * Thread support.
 */


long
PyThread_start_new_thread(void (*func)(void *), void *arg)
{
    pthread_t th;
    int status;
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    pthread_attr_t attrs;
#endif
#if defined(THREAD_STACK_SIZE)
    size_t      tss;
#endif

    dprintf(("PyThread_start_new_thread called\n"));
    if (!initialized)
        PyThread_init_thread();

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    if (pthread_attr_init(&attrs) != 0)
        return -1;
#endif
#if defined(THREAD_STACK_SIZE)
    tss = (_pythread_stacksize != 0) ? _pythread_stacksize
                                     : THREAD_STACK_SIZE;
    if (tss != 0) {
        if (pthread_attr_setstacksize(&attrs, tss) != 0) {
            pthread_attr_destroy(&attrs);
            return -1;
        }
    }
#endif
#if defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    pthread_attr_setscope(&attrs, PTHREAD_SCOPE_SYSTEM);
#endif

    status = pthread_create(&th,
#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
                             &attrs,
#else
                             (pthread_attr_t*)NULL,
#endif
                             (void* (*)(void *))func,
                             (void *)arg
                             );

#if defined(THREAD_STACK_SIZE) || defined(PTHREAD_SYSTEM_SCHED_SUPPORTED)
    pthread_attr_destroy(&attrs);
#endif
    if (status != 0)
        return -1;

    pthread_detach(th);

#if SIZEOF_PTHREAD_T <= SIZEOF_LONG
    return (long) th;
#else
    return (long) *(long *) &th;
#endif
}

/* XXX This implementation is considered (to quote Tim Peters) "inherently
   hosed" because:
     - It does not guarantee the promise that a non-zero integer is returned.
     - The cast to long is inherently unsafe.
     - It is not clear that the 'volatile' (for AIX?) and ugly casting in the
       latter return statement (for Alpha OSF/1) are any longer necessary.
*/
long
PyThread_get_thread_ident(void)
{
    volatile pthread_t threadid;
    if (!initialized)
        PyThread_init_thread();
    /* Jump through some hoops for Alpha OSF/1 */
    threadid = pthread_self();
#if SIZEOF_PTHREAD_T <= SIZEOF_LONG
    return (long) threadid;
#else
    return (long) *(long *) &threadid;
#endif
}

void
PyThread_exit_thread(void)
{
    dprintf(("PyThread_exit_thread called\n"));
    if (!initialized) {
        exit(0);
    }
}

#ifdef USE_SEMAPHORES

/*
 * Lock support.
 */

PyThread_type_lock
PyThread_allocate_lock(void)
{
    sem_t *lock;
    int status, error = 0;

    dprintf(("PyThread_allocate_lock called\n"));
    if (!initialized)
        PyThread_init_thread();

    lock = (sem_t *)malloc(sizeof(sem_t));

    if (lock) {
        status = sem_init(lock,0,1);
        CHECK_STATUS("sem_init");

        if (error) {
            free((void *)lock);
            lock = NULL;
        }
    }

    dprintf(("PyThread_allocate_lock() -> %p\n", lock));
    return (PyThread_type_lock)lock;
}

void
PyThread_free_lock(PyThread_type_lock lock)
{
    sem_t *thelock = (sem_t *)lock;
    int status, error = 0;

    dprintf(("PyThread_free_lock(%p) called\n", lock));

    if (!thelock)
        return;

    status = sem_destroy(thelock);
    CHECK_STATUS("sem_destroy");

    free((void *)thelock);
}

/*
 * As of February 2002, Cygwin thread implementations mistakenly report error
 * codes in the return value of the sem_ calls (like the pthread_ functions).
 * Correct implementations return -1 and put the code in errno. This supports
 * either.
 */
static int
fix_status(int status)
{
    return (status == -1) ? errno : status;
}

PyLockStatus
PyThread_acquire_lock_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds,
                            int intr_flag)
{
    PyLockStatus success;
    sem_t *thelock = (sem_t *)lock;
    int status, error = 0;
    struct timespec ts;

    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) called\n",
             lock, microseconds, intr_flag));

    if (microseconds > 0)
        MICROSECONDS_TO_TIMESPEC(microseconds, ts);
    do {
        if (microseconds > 0)
            status = fix_status(sem_timedwait(thelock, &ts));
        else if (microseconds == 0)
            status = fix_status(sem_trywait(thelock));
        else
            status = fix_status(sem_wait(thelock));
        /* Retry if interrupted by a signal, unless the caller wants to be
           notified.  */
    } while (!intr_flag && status == EINTR);

    /* Don't check the status if we're stopping because of an interrupt.  */
    if (!(intr_flag && status == EINTR)) {
        if (microseconds > 0) {
            if (status != ETIMEDOUT)
                CHECK_STATUS("sem_timedwait");
        }
        else if (microseconds == 0) {
            if (status != EAGAIN)
                CHECK_STATUS("sem_trywait");
        }
        else {
            CHECK_STATUS("sem_wait");
        }
    }

    if (status == 0) {
        success = PY_LOCK_ACQUIRED;
    } else if (intr_flag && status == EINTR) {
        success = PY_LOCK_INTR;
    } else {
        success = PY_LOCK_FAILURE;
    }

    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) -> %d\n",
             lock, microseconds, intr_flag, success));
    return success;
}

void
PyThread_release_lock(PyThread_type_lock lock)
{
    sem_t *thelock = (sem_t *)lock;
    int status, error = 0;

    dprintf(("PyThread_release_lock(%p) called\n", lock));

    status = sem_post(thelock);
    CHECK_STATUS("sem_post");
}

#else /* USE_SEMAPHORES */

/*
 * Lock support.
 */
PyThread_type_lock
PyThread_allocate_lock(void)
{
    pthread_lock *lock;
    int status, error = 0;

    dprintf(("PyThread_allocate_lock called\n"));
    if (!initialized)
        PyThread_init_thread();

    lock = (pthread_lock *) malloc(sizeof(pthread_lock));
    if (lock) {
        memset((void *)lock, '\0', sizeof(pthread_lock));
        lock->locked = 0;

        status = pthread_mutex_init(&lock->mut,
                                    pthread_mutexattr_default);
        CHECK_STATUS("pthread_mutex_init");
        /* Mark the pthread mutex underlying a Python mutex as
           pure happens-before.  We can't simply mark the
           Python-level mutex as a mutex because it can be
           acquired and released in different threads, which
           will cause errors. */
        _Py_ANNOTATE_PURE_HAPPENS_BEFORE_MUTEX(&lock->mut);

        status = pthread_cond_init(&lock->lock_released,
                                   pthread_condattr_default);
        CHECK_STATUS("pthread_cond_init");

        if (error) {
            free((void *)lock);
            lock = 0;
        }
    }

    dprintf(("PyThread_allocate_lock() -> %p\n", lock));
    return (PyThread_type_lock) lock;
}

void
PyThread_free_lock(PyThread_type_lock lock)
{
    pthread_lock *thelock = (pthread_lock *)lock;
    int status, error = 0;

    dprintf(("PyThread_free_lock(%p) called\n", lock));

    status = pthread_mutex_destroy( &thelock->mut );
    CHECK_STATUS("pthread_mutex_destroy");

    status = pthread_cond_destroy( &thelock->lock_released );
    CHECK_STATUS("pthread_cond_destroy");

    free((void *)thelock);
}

PyLockStatus
PyThread_acquire_lock_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds,
                            int intr_flag)
{
    PyLockStatus success;
    pthread_lock *thelock = (pthread_lock *)lock;
    int status, error = 0;

    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) called\n",
             lock, microseconds, intr_flag));

    status = pthread_mutex_lock( &thelock->mut );
    CHECK_STATUS("pthread_mutex_lock[1]");

    if (thelock->locked == 0) {
        success = PY_LOCK_ACQUIRED;
    } else if (microseconds == 0) {
        success = PY_LOCK_FAILURE;
    } else {
        struct timespec ts;
        if (microseconds > 0)
            MICROSECONDS_TO_TIMESPEC(microseconds, ts);
        /* continue trying until we get the lock */

        /* mut must be locked by me -- part of the condition
         * protocol */
        success = PY_LOCK_FAILURE;
        while (success == PY_LOCK_FAILURE) {
            if (microseconds > 0) {
                status = pthread_cond_timedwait(
                    &thelock->lock_released,
                    &thelock->mut, &ts);
                if (status == ETIMEDOUT)
                    break;
                CHECK_STATUS("pthread_cond_timed_wait");
            }
            else {
                status = pthread_cond_wait(
                    &thelock->lock_released,
                    &thelock->mut);
                CHECK_STATUS("pthread_cond_wait");
            }

            if (intr_flag && status == 0 && thelock->locked) {
                /* We were woken up, but didn't get the lock.  We probably received
                 * a signal.  Return PY_LOCK_INTR to allow the caller to handle
                 * it and retry.  */
                success = PY_LOCK_INTR;
                break;
            } else if (status == 0 && !thelock->locked) {
                success = PY_LOCK_ACQUIRED;
            } else {
                success = PY_LOCK_FAILURE;
            }
        }
    }
    if (success == PY_LOCK_ACQUIRED) thelock->locked = 1;
    status = pthread_mutex_unlock( &thelock->mut );
    CHECK_STATUS("pthread_mutex_unlock[1]");

    if (error) success = PY_LOCK_FAILURE;
    dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) -> %d\n",
             lock, microseconds, intr_flag, success));
    return success;
}

void
PyThread_release_lock(PyThread_type_lock lock)
{
    pthread_lock *thelock = (pthread_lock *)lock;
    int status, error = 0;

    dprintf(("PyThread_release_lock(%p) called\n", lock));

    status = pthread_mutex_lock( &thelock->mut );
    CHECK_STATUS("pthread_mutex_lock[3]");

    thelock->locked = 0;

    status = pthread_mutex_unlock( &thelock->mut );
    CHECK_STATUS("pthread_mutex_unlock[3]");

    /* wake up someone (anyone, if any) waiting on the lock */
    status = pthread_cond_signal( &thelock->lock_released );
    CHECK_STATUS("pthread_cond_signal");
}

#endif /* USE_SEMAPHORES */

int
PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
{
    return PyThread_acquire_lock_timed(lock, waitflag ? -1 : 0, /*intr_flag=*/0);
}

/* set the thread stack size.
 * Return 0 if size is valid, -1 if size is invalid,
 * -2 if setting stack size is not supported.
 */
static int
_pythread_pthread_set_stacksize(size_t size)
{
#if defined(THREAD_STACK_SIZE)
    pthread_attr_t attrs;
    size_t tss_min;
    int rc = 0;
#endif

    /* set to default */
    if (size == 0) {
        _pythread_stacksize = 0;
        return 0;
    }

#if defined(THREAD_STACK_SIZE)
#if defined(PTHREAD_STACK_MIN)
    tss_min = PTHREAD_STACK_MIN > THREAD_STACK_MIN ? PTHREAD_STACK_MIN
                                                   : THREAD_STACK_MIN;
#else
    tss_min = THREAD_STACK_MIN;
#endif
    if (size >= tss_min) {
        /* validate stack size by setting thread attribute */
        if (pthread_attr_init(&attrs) == 0) {
            rc = pthread_attr_setstacksize(&attrs, size);
            pthread_attr_destroy(&attrs);
            if (rc == 0) {
                _pythread_stacksize = size;
                return 0;
            }
        }
    }
    return -1;
#else
    return -2;
#endif
}

#define THREAD_SET_STACKSIZE(x) _pythread_pthread_set_stacksize(x)

#define Py_HAVE_NATIVE_TLS

int
PyThread_create_key(void)
{
    pthread_key_t key;
    int fail = pthread_key_create(&key, NULL);
    return fail ? -1 : key;
}

void
PyThread_delete_key(int key)
{
    pthread_key_delete(key);
}

void
PyThread_delete_key_value(int key)
{
    pthread_setspecific(key, NULL);
}

int
PyThread_set_key_value(int key, void *value)
{
    int fail;
    void *oldValue = pthread_getspecific(key);
    if (oldValue != NULL)
        return 0;
    fail = pthread_setspecific(key, value);
    return fail ? -1 : 0;
}

void *
PyThread_get_key_value(int key)
{
    return pthread_getspecific(key);
}

void
PyThread_ReInitTLS(void)
{}