nuttx/sched/pthread/pthread_mutexdestroy.c

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/****************************************************************************
* sched/pthread/pthread_mutexdestroy.c
*
* Copyright (C) 2007-2009, 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 <nuttx/config.h>
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <sched.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/semaphore.h>
#include "pthread/pthread.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pthread_mutex_destroy
*
* Description:
* Destroy a mutex.
*
* Parameters:
* None
*
* Return Value:
* None
*
* Assumptions:
*
****************************************************************************/
int pthread_mutex_destroy(FAR pthread_mutex_t *mutex)
{
int ret = EINVAL;
int status;
sinfo("mutex=0x%p\n", mutex);
DEBUGASSERT(mutex != NULL);
if (mutex != NULL)
{
/* Make sure the semaphore is stable while we make the following checks */
sched_lock();
/* Is the mutex available? */
if (mutex->pid >= 0)
{
DEBUGASSERT(mutex->pid != 0); /* < 0: available, >0 owned, ==0 error */
/* No.. Verify that the PID still exists. We may be destroying
* the mutex after cancelling a pthread and the mutex may have
* been in a bad state owned by the dead pthread. NOTE: The
* following behavior is unspecified for pthread_mutex_destroy()
* (see pthread_mutex_consistent()).
*
* If the holding thread is still valid, then we should be able to
* map its PID to the underlying TCB. That is what sched_gettcb()
* does.
*/
if (sched_gettcb(mutex->pid) == NULL)
{
/* The thread associated with the PID no longer exists */
mutex->pid = -1;
/* Reset the semaphore. If threads are were on this
* semaphore, then this will awakened them and make
* destruction of the semaphore impossible here.
*/
status = sem_reset((FAR sem_t *)&mutex->sem, 1);
if (status < 0)
{
ret = -status;
}
/* Check if the reset caused some other thread to lock the
* mutex.
*/
else if (mutex->pid != -1)
{
/* Yes.. then we cannot destroy the mutex now. */
ret = EBUSY;
}
/* Destroy the underlying semaphore */
else
{
status = sem_destroy((FAR sem_t *)&mutex->sem);
ret = (status != OK) ? get_errno() : OK;
}
}
else
{
ret = EBUSY;
}
}
else
{
/* Destroy the semaphore
*
* REVISIT: What if there are threads waiting on the semaphore?
* Perhaps this logic should all sem_reset() first?
*/
2015-10-08 03:59:14 +02:00
status = sem_destroy((FAR sem_t *)&mutex->sem);
ret = ((status != OK) ? get_errno() : OK);
}
sched_unlock();
}
sinfo("Returning %d\n", ret);
return ret;
}