freebsd-dev/lib/libc_r/uthread/uthread_cond.c
Julian Elischer 012dfd00b3 Reviewed by: julian
Submitted by:	 john birrel

One version of the pthreads library
another will follow with differnt actions under some cases..
not QUITE complete
1996-01-22 00:23:58 +00:00

294 lines
7.6 KiB
C

/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* 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 John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
*/
#include <stdlib.h>
#include <errno.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
int
pthread_cond_init(pthread_cond_t * cond, const pthread_condattr_t * cond_attr)
{
enum pthread_cond_type type;
int rval = 0;
/*
* Check if a pointer to a condition variable attribute structure was
* passed by the caller:
*/
if (cond_attr != NULL) {
/* Default to a fast condition variable: */
type = cond_attr->c_type;
} else {
/* Default to a fast condition variable: */
type = COND_TYPE_FAST;
}
/* Process according to condition variable type: */
switch (type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Nothing to do here. */
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Check for no errors: */
if (rval == 0) {
/* Initialise the condition variable structure: */
_thread_queue_init(&cond->c_queue);
cond->c_flags |= COND_FLAGS_INITED;
cond->c_type = type;
}
/* Return the completion status: */
return (rval);
}
int
pthread_cond_destroy(pthread_cond_t * cond)
{
int rval = 0;
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Nothing to do here. */
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Check for errors: */
if (rval == 0) {
/* Destroy the contents of the condition structure: */
_thread_queue_init(&cond->c_queue);
cond->c_flags = 0;
}
/* Return the completion status: */
return (rval);
}
int
pthread_cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex)
{
int rval = 0;
int status;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Queue the running thread for the condition variable: */
_thread_queue_enq(&cond->c_queue, _thread_run);
/* Unlock the mutex: */
pthread_mutex_unlock(mutex);
/* Schedule the next thread: */
_thread_kern_sched_state(PS_COND_WAIT, __FILE__, __LINE__);
/* Block signals: */
_thread_kern_sig_block(NULL);
/* Lock the mutex: */
rval = pthread_mutex_lock(mutex);
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
int
pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex,
const struct timespec * abstime)
{
int rval = 0;
int status;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Set the wakeup time: */
_thread_run->wakeup_time.ts_sec = abstime->ts_sec;
_thread_run->wakeup_time.ts_nsec = abstime->ts_nsec;
/* Reset the timeout flag: */
_thread_run->timeout = 0;
/* Queue the running thread for the condition variable: */
_thread_queue_enq(&cond->c_queue, _thread_run);
/* Unlock the mutex: */
if ((rval = pthread_mutex_unlock(mutex)) != 0) {
/*
* Cannot unlock the mutex, so remove the running
* thread from the condition variable queue:
*/
_thread_queue_deq(&cond->c_queue);
} else {
/* Schedule the next thread: */
_thread_kern_sched_state(PS_COND_WAIT, __FILE__, __LINE__);
/* Block signals: */
_thread_kern_sig_block(NULL);
/* Lock the mutex: */
if ((rval = pthread_mutex_lock(mutex)) != 0) {
}
/* Check if the wait timed out: */
else if (_thread_run->timeout) {
/* Return a timeout error: */
_thread_seterrno(_thread_run, EAGAIN);
rval = -1;
}
}
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
int
pthread_cond_signal(pthread_cond_t * cond)
{
int rval = 0;
int status;
pthread_t pthread;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Bring the next thread off the condition queue: */
if ((pthread = _thread_queue_deq(&cond->c_queue)) != NULL) {
/* Allow the thread to run: */
pthread->state = PS_RUNNING;
}
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
int
pthread_cond_broadcast(pthread_cond_t * cond)
{
int rval = 0;
int status;
pthread_t pthread;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Enter a loop to bring all threads off the condition queue: */
while ((pthread = _thread_queue_deq(&cond->c_queue)) != NULL) {
/* Allow the thread to run: */
pthread->state = PS_RUNNING;
}
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
#endif