mariadb/mit-pthreads/pthreads/cond.c
bk@work.mysql.com f4c589ff6c Import changeset
2000-07-31 21:29:14 +02:00

437 lines
12 KiB
C

/* ==== cond.c ============================================================
* Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Chris Provenzano.
* 4. The name of Chris Provenzano may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL CHRIS PROVENZANO BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Description : Condition variable functions.
*
* 1.00 93/10/28 proven
* -Started coding this file.
*/
#ifndef lint
static const char rcsid[] = "$Id$";
#endif
#include <pthread.h>
#include <sys/time.h>
#include <stdlib.h>
#include <timers.h>
#include <errno.h>
#ifndef ETIME
#define ETIME ETIMEDOUT
#endif
/* ==========================================================================
* pthread_cond_is_debug()
*
* Check that cond is a debug cond and if so returns entry number into
* array of debug condes.
*/
static int pthread_cond_debug_count = 0;
static pthread_cond_t ** pthread_cond_debug_ptrs = NULL;
static pthread_mutex_t pthread_cond_debug_mutex = PTHREAD_MUTEX_INITIALIZER;
static inline int pthread_cond_is_debug(pthread_cond_t * cond)
{
int i;
for (i = 0; i < pthread_cond_debug_count; i++) {
if (pthread_cond_debug_ptrs[i] == cond) {
return(i);
}
}
return(NOTOK);
}
/* ==========================================================================
* pthread_cond_init()
*
* In this implementation I don't need to allocate memory.
* ENOMEM, EAGAIN should never be returned. Arch that have
* weird constraints may need special coding.
*/
int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr)
{
enum pthread_condtype type;
/* Only check if attr specifies some mutex type other than fast */
if ((cond_attr) && (cond_attr->c_type != COND_TYPE_FAST)) {
if (cond_attr->c_type >= COND_TYPE_MAX) {
return(EINVAL);
}
type = cond_attr->c_type;
} else {
type = COND_TYPE_FAST;
}
switch (type) {
case COND_TYPE_FAST:
case COND_TYPE_COUNTING_FAST:
break;
case COND_TYPE_DEBUG:
pthread_mutex_lock(&pthread_cond_debug_mutex);
if (pthread_cond_is_debug(cond) == NOTOK) {
pthread_cond_t ** new;
if ((new = (pthread_cond_t **)realloc(pthread_cond_debug_ptrs,
(pthread_cond_debug_count + 1) * (sizeof(void *)))) == NULL) {
pthread_mutex_unlock(&pthread_cond_debug_mutex);
return(ENOMEM);
}
pthread_cond_debug_ptrs = new;
pthread_cond_debug_ptrs[pthread_cond_debug_count++] = cond;
} else {
pthread_mutex_unlock(&pthread_cond_debug_mutex);
return(EBUSY);
}
pthread_mutex_unlock(&pthread_cond_debug_mutex);
break;
case COND_TYPE_STATIC_FAST:
defualt:
return(EINVAL);
break;
}
/* Set all other paramaters */
pthread_queue_init(&cond->c_queue);
cond->c_flags |= COND_FLAGS_INITED;
cond->c_type = type;
return(OK);
}
/* ==========================================================================
* pthread_cond_destroy()
*/
int pthread_cond_destroy(pthread_cond_t *cond)
{
int i;
/* Only check if cond is of type other than fast */
switch(cond->c_type) {
case COND_TYPE_FAST:
case COND_TYPE_COUNTING_FAST:
break;
case COND_TYPE_DEBUG:
if (pthread_queue_get(&(cond->c_queue))) {
return(EBUSY);
}
pthread_mutex_lock(&pthread_cond_debug_mutex);
if ((i = pthread_cond_is_debug(cond)) == NOTOK) {
pthread_mutex_unlock(&pthread_cond_debug_mutex);
return(EINVAL);
}
/* Remove the cond from the list of debug condition variables */
pthread_cond_debug_ptrs[i] =
pthread_cond_debug_ptrs[--pthread_cond_debug_count];
pthread_cond_debug_ptrs[pthread_cond_debug_count] = NULL;
pthread_mutex_unlock(&pthread_cond_debug_mutex);
break;
case COND_TYPE_STATIC_FAST:
default:
return(EINVAL);
break;
}
/* Cleanup cond, others might want to use it. */
pthread_queue_init(&cond->c_queue);
cond->c_flags = 0;
return(OK);
}
/* ==========================================================================
* pthread_cond_wait()
*/
int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
{
int rval;
pthread_sched_prevent();
switch (cond->c_type) {
case COND_TYPE_DEBUG:
pthread_mutex_lock(&pthread_cond_debug_mutex);
if (pthread_cond_is_debug(cond) == NOTOK) {
pthread_mutex_unlock(&pthread_cond_debug_mutex);
pthread_sched_resume();
return(EINVAL);
}
pthread_mutex_unlock(&pthread_cond_debug_mutex);
/*
* Fast condition variables do not check for any error conditions.
*/
case COND_TYPE_FAST:
case COND_TYPE_STATIC_FAST:
pthread_queue_enq(&cond->c_queue, pthread_run);
pthread_mutex_unlock(mutex);
pthread_run->data.mutex = mutex;
SET_PF_WAIT_EVENT(pthread_run);
SET_PF_AT_CANCEL_POINT(pthread_run); /* This is a cancel point */
/* Reschedule will unlock pthread_run */
pthread_resched_resume(PS_COND_WAIT);
CLEAR_PF_AT_CANCEL_POINT(pthread_run); /* No longer at cancel point */
CLEAR_PF_DONE_EVENT(pthread_run);
pthread_run->data.mutex = NULL;
rval = pthread_mutex_lock(mutex);
return(rval);
break;
case COND_TYPE_COUNTING_FAST:
{
int count = mutex->m_data.m_count;
pthread_queue_enq(&cond->c_queue, pthread_run);
pthread_mutex_unlock(mutex);
mutex->m_data.m_count = 1;
pthread_run->data.mutex = mutex;
SET_PF_WAIT_EVENT(pthread_run);
SET_PF_AT_CANCEL_POINT(pthread_run); /* This is a cancel point */
/* Reschedule will unlock pthread_run */
pthread_resched_resume(PS_COND_WAIT);
CLEAR_PF_AT_CANCEL_POINT(pthread_run); /* No longer at cancel point */
CLEAR_PF_DONE_EVENT(pthread_run);
pthread_run->data.mutex = NULL;
rval = pthread_mutex_lock(mutex);
mutex->m_data.m_count = count;
return(rval);
break;
}
default:
rval = EINVAL;
break;
}
pthread_sched_resume();
return(rval);
}
/* ==========================================================================
* pthread_cond_timedwait()
*/
int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
const struct timespec * abstime)
{
struct timespec current_time, new_time;
int rval = OK;
pthread_sched_prevent();
machdep_gettimeofday(& current_time);
switch (cond->c_type) {
case COND_TYPE_DEBUG:
pthread_mutex_lock(&pthread_cond_debug_mutex);
if (pthread_cond_is_debug(cond) == NOTOK) {
pthread_mutex_unlock(&pthread_cond_debug_mutex);
pthread_sched_resume();
return(EINVAL);
}
pthread_mutex_unlock(&pthread_cond_debug_mutex);
/*
* Fast condition variables do not check for any error conditions.
*/
case COND_TYPE_FAST:
case COND_TYPE_STATIC_FAST:
/* Set pthread wakeup time*/
pthread_run->wakeup_time = *abstime;
/* Install us on the sleep queue */
sleep_schedule (&current_time, &(pthread_run->wakeup_time));
pthread_queue_enq(&cond->c_queue, pthread_run);
SET_PF_WAIT_EVENT(pthread_run);
pthread_mutex_unlock(mutex);
pthread_run->data.mutex = mutex;
SET_PF_AT_CANCEL_POINT(pthread_run); /* This is a cancel point */
/* Reschedule will unlock pthread_run */
pthread_resched_resume(PS_COND_WAIT);
CLEAR_PF_AT_CANCEL_POINT(pthread_run); /* No longer at cancel point */
pthread_run->data.mutex = NULL;
/* Remove ourselves from sleep queue. If we fail then we timedout */
if (sleep_cancel(pthread_run) == NOTOK) {
SET_ERRNO(ETIME);
rval = ETIME;
}
CLEAR_PF_DONE_EVENT(pthread_run);
pthread_mutex_lock(mutex);
return(rval);
break;
case COND_TYPE_COUNTING_FAST:
{
int count = mutex->m_data.m_count;
/* Set pthread wakeup time*/
pthread_run->wakeup_time = *abstime;
/* Install us on the sleep queue */
sleep_schedule (&current_time, &(pthread_run->wakeup_time));
pthread_queue_enq(&cond->c_queue, pthread_run);
SET_PF_WAIT_EVENT(pthread_run);
pthread_mutex_unlock(mutex);
pthread_run->data.mutex = mutex;
SET_PF_AT_CANCEL_POINT(pthread_run); /* This is a cancel point */
/* Reschedule will unlock pthread_run */
pthread_resched_resume(PS_COND_WAIT);
CLEAR_PF_AT_CANCEL_POINT(pthread_run); /* No longer at cancel point */
pthread_run->data.mutex = NULL;
/* Remove ourselves from sleep queue. If we fail then we timedout */
if (sleep_cancel(pthread_run) == NOTOK) {
SET_ERRNO(ETIME);
rval = ETIME;
}
CLEAR_PF_DONE_EVENT(pthread_run);
pthread_mutex_lock(mutex);
mutex->m_data.m_count = count;
return(rval);
break;
}
default:
rval = EINVAL;
break;
}
pthread_sched_resume();
return(rval);
}
/* ==========================================================================
* pthread_cond_signal()
*/
int pthread_cond_signal(pthread_cond_t *cond)
{
struct pthread *pthread;
int rval;
pthread_sched_prevent();
switch (cond->c_type) {
case COND_TYPE_DEBUG:
pthread_mutex_lock(&pthread_cond_debug_mutex);
if (pthread_cond_is_debug(cond) == NOTOK) {
pthread_mutex_unlock(&pthread_cond_debug_mutex);
pthread_sched_resume();
return(EINVAL);
}
pthread_mutex_unlock(&pthread_cond_debug_mutex);
case COND_TYPE_FAST:
case COND_TYPE_STATIC_FAST:
if (pthread = pthread_queue_deq(&cond->c_queue)) {
if ((SET_PF_DONE_EVENT(pthread)) == OK) {
pthread_sched_other_resume(pthread);
} else {
pthread_sched_resume();
}
return(OK);
}
rval = OK;
break;
default:
rval = EINVAL;
break;
}
pthread_sched_resume();
return(rval);
}
/* ==========================================================================
* pthread_cond_broadcast()
*
* Not much different then the above routine.
*/
int pthread_cond_broadcast(pthread_cond_t *cond)
{
struct pthread * pthread, * high_pthread, * low_pthread;
int rval;
pthread_sched_prevent();
switch (cond->c_type) {
case COND_TYPE_DEBUG:
pthread_mutex_lock(&pthread_cond_debug_mutex);
if (pthread_cond_is_debug(cond) == NOTOK) {
pthread_mutex_unlock(&pthread_cond_debug_mutex);
pthread_sched_resume();
return(EINVAL);
}
pthread_mutex_unlock(&pthread_cond_debug_mutex);
case COND_TYPE_FAST:
case COND_TYPE_STATIC_FAST:
if (pthread = pthread_queue_deq(&cond->c_queue)) {
pthread->state = PS_RUNNING;
high_pthread = pthread;
while (pthread = pthread_queue_deq(&cond->c_queue)) {
if (pthread->pthread_priority >
high_pthread->pthread_priority) {
low_pthread = high_pthread;
high_pthread = pthread;
} else {
low_pthread = pthread;
}
if ((SET_PF_DONE_EVENT(low_pthread)) == OK) {
pthread_prio_queue_enq(pthread_current_prio_queue,
low_pthread);
low_pthread->state = PS_RUNNING;
}
}
if ((SET_PF_DONE_EVENT(high_pthread)) == OK) {
pthread_sched_other_resume(high_pthread);
} else {
pthread_sched_resume();
}
return(OK);
}
rval = OK;
break;
default:
rval = EINVAL;
break;
}
pthread_sched_resume();
return(rval);
}