/************************************************************
* pthread_condwait.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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. Neither the name Gregory Nutt nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
************************************************************/
/************************************************************
* Included Files
************************************************************/
#include <sys/types.h>
#include <unistd.h>
#include <pthread.h>
#include <sched.h>
#include <errno.h>
#include <debug.h>
#include "pthread_internal.h"
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Global Variables
************************************************************/
/************************************************************
* Private Variables
************************************************************/
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Function: int pthread_cond_wait
*
* Description:
* A thread can wait for a condition variable to be
* signalled or broadcast.
*
* Parameters:
* None
*
* Return Value:
* None
*
* Assumptions:
*
************************************************************/
int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
{
int ret;
dbg("cond=0x%p mutex=0x%p\n", cond, mutex);
/* Make sure that non-NULL references were provided. */
if (!cond || !mutex)
{
ret = EINVAL;
}
/* Make sure that the caller holds the mutex */
else if (mutex->pid != (int)getpid())
{
ret = EPERM;
}
else
{
/* Give up the mutex */
dbg("Give up mutex / take cond\n");
sched_lock();
mutex->pid = 0;
ret = pthread_givesemaphore((sem_t*)&mutex->sem);
/* Take the semaphore */
ret |= pthread_takesemaphore((sem_t*)&cond->sem);
sched_unlock();
/* Reacquire the mutex */
dbg("Reacquire mutex...\n");
ret |= pthread_takesemaphore((sem_t*)&mutex->sem);
if (!ret)
{
mutex->pid = getpid();;
}
}
dbg("Returning %d\n", ret);
return ret;
}
