152 lines
4.4 KiB
C
152 lines
4.4 KiB
C
/****************************************************************************
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* sched/pthread/pthread_mutexdestroy.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <pthread.h>
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#include <signal.h>
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#include <sched.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/semaphore.h>
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#include "pthread/pthread.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pthread_mutex_destroy
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*
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* Description:
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* Destroy a mutex.
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*
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* Input Parameters:
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* None
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*
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* Returned Value:
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* None
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*
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* Assumptions:
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*
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****************************************************************************/
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int pthread_mutex_destroy(FAR pthread_mutex_t *mutex)
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{
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int ret = EINVAL;
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int status;
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sinfo("mutex=%p\n", mutex);
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DEBUGASSERT(mutex != NULL);
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if (mutex != NULL)
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{
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/* Make sure the semaphore is stable while we make the following
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* checks.
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*/
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sched_lock();
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/* Is the mutex available? */
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if (mutex->pid >= 0)
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{
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/* < 0: available, >0 owned, ==0 error */
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DEBUGASSERT(mutex->pid != 0);
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/* No.. Verify that the PID still exists. We may be destroying
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* the mutex after cancelling a pthread and the mutex may have
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* been in a bad state owned by the dead pthread. NOTE: The
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* following behavior is unspecified for pthread_mutex_destroy()
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* (see pthread_mutex_consistent()).
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*
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* If the holding thread is still valid, then we should be able to
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* map its PID to the underlying TCB. That is what
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* nxsched_get_tcb() does.
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*/
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if (nxsched_get_tcb(mutex->pid) == NULL)
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{
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/* The thread associated with the PID no longer exists */
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mutex->pid = INVALID_PROCESS_ID;
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/* Reset the semaphore. If threads are were on this
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* semaphore, then this will awakened them and make
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* destruction of the semaphore impossible here.
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*/
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status = nxsem_reset(&mutex->sem, 1);
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if (status < 0)
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{
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ret = -status;
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}
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/* Check if the reset caused some other thread to lock the
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* mutex.
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*/
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else if (mutex->pid != INVALID_PROCESS_ID)
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{
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/* Yes.. then we cannot destroy the mutex now. */
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ret = EBUSY;
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}
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/* Destroy the underlying semaphore */
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else
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{
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status = nxsem_destroy(&mutex->sem);
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ret = (status < 0) ? -status : OK;
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}
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}
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else
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{
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ret = EBUSY;
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}
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}
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else
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{
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/* Destroy the semaphore
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*
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* REVISIT: What if there are threads waiting on the semaphore?
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* Perhaps this logic should all nxsem_reset() first?
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*/
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status = nxsem_destroy(&mutex->sem);
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ret = ((status < 0) ? -status : OK);
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}
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sched_unlock();
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}
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sinfo("Returning %d\n", ret);
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return ret;
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}
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