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/****************************************************************************
* NCSA HDF *
* Software Development Group *
* National Center for Supercomputing Applications *
* University of Illinois at Urbana-Champaign *
* 605 E. Springfield, Champaign IL 61820 *
* *
* For conditions of distribution and use, see the accompanying *
* hdf/COPYING file. *
* *
****************************************************************************/
#ifdef RCSID
static char RcsId[] = "@(#)$Revision$";
#endif
/* $Id$ */
/* private headers */
#include <H5private.h> /*library */
#include <H5Eprivate.h> /*error handling */
#ifdef H5_HAVE_THREADSAFE
/* Module specific data structures */
/* cancelability structure */
typedef struct H5TS_cancel_struct {
int previous_state;
unsigned int cancel_count;
} H5TS_cancel_t;
/* Global variable definitions */
pthread_once_t H5TS_first_init_g = PTHREAD_ONCE_INIT;
pthread_key_t H5TS_errstk_key_g;
pthread_key_t H5TS_cancel_key_g;
hbool_t H5TS_allow_concurrent_g = FALSE; /* concurrent APIs override this */
/* Local function definitions */
#ifdef NOT_USED
static void H5TS_mutex_init(H5TS_mutex_t *mutex);
#endif /* NOT_USED */
/*--------------------------------------------------------------------------
* NAME
* H5TS_first_thread_init
* USAGE
* H5TS_first_thread_init()
*
* RETURNS
*
* DESCRIPTION
* Initialization of global API lock, keys for per-thread error stacks
* and cancallability information. Called by the first thread that enters
* the library.
*
* PROGRAMMER: Chee Wai LEE
* May 2, 2000
*
* MODIFICATIONS:
*
*--------------------------------------------------------------------------
*/
void
H5TS_first_thread_init(void)
{
/* initialize global API mutex lock */
H5_g.H5_libinit_g = FALSE;
H5_g.init_lock.owner_thread = NULL;
pthread_mutex_init(&H5_g.init_lock.atomic_lock, NULL);
pthread_cond_init(&H5_g.init_lock.cond_var, NULL);
H5_g.init_lock.lock_count = 0;
/* initialize key for thread-specific error stacks */
pthread_key_create(&H5TS_errstk_key_g, NULL);
/* initialize key for thread cancellability mechanism */
pthread_key_create(&H5TS_cancel_key_g, NULL);
}
#ifdef NOT_USED
/*--------------------------------------------------------------------------
* NAME
* H5TS_mutex_init
* USAGE
* H5TS_mutex_init(&mutex_var)
*
* RETURNS
*
* DESCRIPTION
* Recursive lock semantics for HDF5 (lock initialization) -
* Multiple acquisition of a lock by a thread is permitted with a
* corresponding unlock operation required.
*
* PROGRAMMER: Chee Wai LEE
* May 2, 2000
*
* MODIFICATIONS:
*
*--------------------------------------------------------------------------
*/
static void
H5TS_mutex_init(H5TS_mutex_t *mutex)
{
(*mutex).owner_thread = NULL;
pthread_mutex_init(&(*mutex).atomic_lock, NULL);
pthread_cond_init(&(*mutex).cond_var, NULL);
(*mutex).lock_count = 0;
}
#endif /* NOT_USED */
/*--------------------------------------------------------------------------
* NAME
* H5TS_mutex_lock
* USAGE
* H5TS_mutex_lock(&mutex_var)
*
* RETURNS
*
* DESCRIPTION
* Recursive lock semantics for HDF5 (locking) -
* Multiple acquisition of a lock by a thread is permitted with a
* corresponding unlock operation required.
*
* PROGRAMMER: Chee Wai LEE
* May 2, 2000
*
* MODIFICATIONS:
*
*--------------------------------------------------------------------------
*/
void
H5TS_mutex_lock(H5TS_mutex_t *mutex)
{
pthread_mutex_lock(&(*mutex).atomic_lock);
if (pthread_equal(pthread_self(), (*mutex).owner_thread)) {
/* already owned by self - increment count */
(*mutex).lock_count++;
} else {
if ((*mutex).owner_thread == NULL) {
/* no one else has locked it - set owner and grab lock */
(*mutex).owner_thread = pthread_self();
(*mutex).lock_count = 1;
} else {
/* if already locked by someone else */
while (1) {
pthread_cond_wait(&(*mutex).cond_var, &(*mutex).atomic_lock);
if ((*mutex).owner_thread == NULL) {
(*mutex).owner_thread = pthread_self();
(*mutex).lock_count = 1;
break;
} /* else do nothing and loop back to wait on condition*/
}
}
}
pthread_mutex_unlock(&(*mutex).atomic_lock);
}
/*--------------------------------------------------------------------------
* NAME
* H5TS_mutex_unlock
* USAGE
* H5TS_mutex_unlock(&mutex_var)
*
* RETURNS
*
* DESCRIPTION
* Recursive lock semantics for HDF5 (unlocking) -
* Multiple acquisition of a lock by a thread is permitted with a
* corresponding unlock operation required.
*
* PROGRAMMER: Chee Wai LEE
* May 2, 2000
*
* MODIFICATIONS:
*
*--------------------------------------------------------------------------
*/
void
H5TS_mutex_unlock(H5TS_mutex_t *mutex)
{
pthread_mutex_lock(&(*mutex).atomic_lock);
(*mutex).lock_count--;
if ((*mutex).lock_count == 0) {
(*mutex).owner_thread = NULL;
pthread_cond_signal(&(*mutex).cond_var);
}
pthread_mutex_unlock(&(*mutex).atomic_lock);
}
/*--------------------------------------------------------------------------
* NAME
* H5TS_cancel_count_inc
* USAGE
* H5TS_cancel_count_inc()
*
* RETURNS
*
* DESCRIPTION
* Creates a cancelation counter for a thread if it is the first time
* the thread is entering the library.
*
* if counter value is zero, then set cancelability type of the thread
* to PTHREAD_CANCEL_DISABLE as thread is entering the library and store
* the previous cancelability type into cancelation counter.
* Increase the counter value by 1.
*
* PROGRAMMER: Chee Wai LEE
* May 2, 2000
*
* MODIFICATIONS:
*
*--------------------------------------------------------------------------
*/
void
H5TS_cancel_count_inc(void)
{
H5TS_cancel_t *cancel_counter;
if ((cancel_counter = pthread_getspecific(H5TS_cancel_key_g))!=NULL) {
/* do nothing here */
} else {
/* first time thread calls library - create new counter and associate
* with key
*/
cancel_counter = (H5TS_cancel_t *)malloc(sizeof(H5TS_cancel_t));
cancel_counter->cancel_count = 0;
pthread_setspecific(H5TS_cancel_key_g, (void *)cancel_counter);
}
if (cancel_counter->cancel_count == 0) {
/* thread entering library */
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &(cancel_counter->previous_state));
}
cancel_counter->cancel_count++;
}
/*--------------------------------------------------------------------------
* NAME
* H5TS_cancel_count_dec
* USAGE
* H5TS_cancel_count_dec()
*
* RETURNS
*
* DESCRIPTION
* if counter value is one, then set cancelability type of the thread
* to the previous cancelability type stored in the cancelation counter.
* (the thread is leaving the library).
*
* Decrement the counter value by 1.
*
* PROGRAMMER: Chee Wai LEE
* May 2, 2000
*
* MODIFICATIONS:
*
*--------------------------------------------------------------------------
*/
void
H5TS_cancel_count_dec(void)
{
H5TS_cancel_t *cancel_counter = pthread_getspecific(H5TS_cancel_key_g);
if (cancel_counter->cancel_count == 1) {
pthread_setcancelstate(cancel_counter->previous_state, NULL);
}
cancel_counter->cancel_count--;
}
#endif
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