/* 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)

#  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

/* 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

}

static void 

do_PyThread_exit_thread(int no_cleanup)

{

	dprintf(("PyThread_exit_thread called\n"));

	if (!initialized) {

		if (no_cleanup)

			_exit(0);

		else

			exit(0);

	}

}

void 

PyThread_exit_thread(void)

{

	do_PyThread_exit_thread(0);

}

void 

PyThread__exit_thread(void)

{

	do_PyThread_exit_thread(1);

}

#ifndef NO_EXIT_PROG

static void 

do_PyThread_exit_prog(int status, int no_cleanup)

{

	dprintf(("PyThread_exit_prog(%d) called\n", status));

	if (!initialized)

		if (no_cleanup)

			_exit(status);

		else

			exit(status);

}

void 

PyThread_exit_prog(int status)

{

	do_PyThread_exit_prog(status, 0);

}

void 

PyThread__exit_prog(int status)

{

	do_PyThread_exit_prog(status, 1);

}

#endif /* NO_EXIT_PROG */

#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;

}

int 

PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)

{

	int success;

	sem_t *thelock = (sem_t *)lock;

	int status, error = 0;

	dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag));

	do {

		if (waitflag)

			status = fix_status(sem_wait(thelock));

		else

			status = fix_status(sem_trywait(thelock));

	} while (status == EINTR); /* Retry if interrupted by a signal */

	if (waitflag) {

		CHECK_STATUS("sem_wait");

	} else if (status != EAGAIN) {

		CHECK_STATUS("sem_trywait");

	}

	success = (status == 0) ? 1 : 0;

	dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, 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");

		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);

}

int 

PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)

{

	int success;

	pthread_lock *thelock = (pthread_lock *)lock;

	int status, error = 0;

	dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag));

	status = pthread_mutex_lock( &thelock->mut );

	CHECK_STATUS("pthread_mutex_lock[1]");

	success = thelock->locked == 0;

	if ( !success && waitflag ) {

		/* continue trying until we get the lock */

		/* mut must be locked by me -- part of the condition

		 * protocol */

		while ( thelock->locked ) {

			status = pthread_cond_wait(&thelock->lock_released,

						   &thelock->mut);

			CHECK_STATUS("pthread_cond_wait");

		}

		success = 1;

	}

	if (success) thelock->locked = 1;

	status = pthread_mutex_unlock( &thelock->mut );

	CHECK_STATUS("pthread_mutex_unlock[1]");

	if (error) success = 0;

	dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, 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 */

/* 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