/* 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

/* The default stack size for new threads on OSX and BSD is small enough that
 * we'll get hard crashes instead of 'maximum recursion depth exceeded'
 * exceptions.
 *
 * The default stack sizes below are the empirically determined minimal stack
 * sizes where a simple recursive function doesn't cause a hard crash.
 */
#if defined(__APPLE__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE 0x500000
#endif
#if defined(__FreeBSD__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
#undef THREAD_STACK_SIZE
#define THREAD_STACK_SIZE 0x400000
#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; }
#define CHECK_STATUS_PTHREAD(name) if (status != 0) { fprintf(stderr, \
 "%s: %s\n", name, strerror(status)); error = 1; }

/*
 * Initialization.
 */

#if defined(_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__)
 extern void pthread_init(void);
 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?) are any longer necessary.
*/
long
PyThread_get_thread_ident(void)
{
 volatile pthread_t threadid;
 if (!initialized)
 PyThread_init_thread();
 threadid = pthread_self();
 return (long) threadid;
}

void
PyThread_exit_thread(void)
{
 dprintf(("PyThread_exit_thread called\n"));
 if (!initialized)
 exit(0);
 pthread_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 *)PyMem_RawMalloc(sizeof(sem_t));

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

 if (error) {
 PyMem_RawFree((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;

 (void) error; /* silence unused-but-set-variable warning */
 dprintf(("PyThread_free_lock(%p) called\n", lock));

 if (!thelock)
 return;

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

 PyMem_RawFree((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;

 (void) error; /* silence unused-but-set-variable warning */
 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;

 (void) error; /* silence unused-but-set-variable warning */
 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 *) PyMem_RawMalloc(sizeof(pthread_lock));
 if (lock) {
 memset((void *)lock, '0円', sizeof(pthread_lock));
 lock->locked = 0;

 status = pthread_mutex_init(&lock->mut,
 pthread_mutexattr_default);
 CHECK_STATUS_PTHREAD("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("pthread_cond_init");

 if (error) {
 PyMem_RawFree((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;

 (void) error; /* silence unused-but-set-variable warning */
 dprintf(("PyThread_free_lock(%p) called\n", lock));

 /* some pthread-like implementations tie the mutex to the cond
 * and must have the cond destroyed first.
 */
 status = pthread_cond_destroy( &thelock->lock_released );
 CHECK_STATUS_PTHREAD("pthread_cond_destroy");

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

 PyMem_RawFree((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("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("pthread_cond_timed_wait");
 }
 else {
 status = pthread_cond_wait(
 &thelock->lock_released,
 &thelock->mut);
 CHECK_STATUS_PTHREAD("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("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;

 (void) error; /* silence unused-but-set-variable warning */
 dprintf(("PyThread_release_lock(%p) called\n", lock));

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

 thelock->locked = 0;

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

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

#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);
 if (fail)
 return -1;
 if (key > INT_MAX) {
 /* Issue #22206: handle integer overflow */
 pthread_key_delete(key);
 errno = ENOMEM;
 return -1;
 }
 return (int)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;
 fail = pthread_setspecific(key, value);
 return fail ? -1 : 0;
}

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

void
PyThread_ReInitTLS(void)
{}