211 lines
7.1 KiB
C
211 lines
7.1 KiB
C
/****************************************************************************
|
|
* sched/pthread/pthread_mutextimedlock.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <unistd.h>
|
|
#include <pthread.h>
|
|
#include <sched.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/sched.h>
|
|
|
|
#include "pthread/pthread.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: pthread_mutex_timedlock
|
|
*
|
|
* Description:
|
|
* The pthread_mutex_timedlock() function will lock the mutex object
|
|
* referenced by mutex. If the mutex is already locked, the calling
|
|
* thread will block until the mutex becomes available as in the
|
|
* pthread_mutex_lock() function. If the mutex cannot be locked without
|
|
* waiting for another thread to unlock the mutex, this wait will be
|
|
* terminated when the specified timeout expires.
|
|
*
|
|
* The timeout will expire when the absolute time specified by
|
|
* abs_timeout passes, as measured by the clock on which timeouts are
|
|
* based (that is, when the value of that clock equals or exceeds
|
|
* abs_timeout), or if the absolute time specified by abs_timeout
|
|
* has already been passed at the time of the call.
|
|
*
|
|
* Input Parameters:
|
|
* mutex - A reference to the mutex to be locked.
|
|
* abs_timeout - max wait time (NULL wait forever)
|
|
*
|
|
* Returned Value:
|
|
* 0 on success or an errno value on failure. Note that the errno EINTR
|
|
* is never returned by pthread_mutex_timedlock().
|
|
* errno is ETIMEDOUT if mutex could not be locked before the specified
|
|
* timeout expired
|
|
*
|
|
* Assumptions:
|
|
*
|
|
* POSIX Compatibility:
|
|
* - This implementation does not return EAGAIN when the mutex could not be
|
|
* acquired because the maximum number of recursive locks for mutex has
|
|
* been exceeded.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int pthread_mutex_timedlock(FAR pthread_mutex_t *mutex,
|
|
FAR const struct timespec *abs_timeout)
|
|
{
|
|
pid_t mypid = getpid();
|
|
int ret = EINVAL;
|
|
|
|
sinfo("mutex=%p\n", mutex);
|
|
DEBUGASSERT(mutex != NULL);
|
|
|
|
if (mutex != NULL)
|
|
{
|
|
/* Make sure the semaphore is stable while we make the following
|
|
* checks. This all needs to be one atomic action.
|
|
*/
|
|
|
|
sched_lock();
|
|
|
|
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
|
|
/* All mutex types except for NORMAL (and DEFAULT) will return
|
|
* an error if the caller does not hold the mutex.
|
|
*/
|
|
|
|
if (mutex->type != PTHREAD_MUTEX_NORMAL && mutex->pid == mypid)
|
|
{
|
|
/* Yes... Is this a recursive mutex? */
|
|
|
|
if (mutex->type == PTHREAD_MUTEX_RECURSIVE)
|
|
{
|
|
/* Yes... just increment the number of locks held and return
|
|
* success.
|
|
*/
|
|
|
|
if (mutex->nlocks < INT16_MAX)
|
|
{
|
|
mutex->nlocks++;
|
|
ret = OK;
|
|
}
|
|
else
|
|
{
|
|
ret = EOVERFLOW;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* No, then we would deadlock... return an error (default
|
|
* behavior is like PTHREAD_MUTEX_ERRORCHECK)
|
|
*
|
|
* NOTE: This is the correct behavior for a 'robust', NORMAL
|
|
* mutex. Compliant behavior for non-robust mutex should not
|
|
* include these checks. In that case, the deadlock condition
|
|
* should not be detected and the thread should be permitted
|
|
* to deadlock.
|
|
*/
|
|
|
|
serr("ERROR: Returning EDEADLK\n");
|
|
ret = EDEADLK;
|
|
}
|
|
}
|
|
else
|
|
#endif /* CONFIG_PTHREAD_MUTEX_TYPES */
|
|
|
|
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
|
|
/* The calling thread does not hold the semaphore. The correct
|
|
* behavior for the 'robust' mutex is to verify that the holder of the
|
|
* mutex is still valid. This is protection from the case
|
|
* where the holder of the mutex has exited without unlocking it.
|
|
*/
|
|
|
|
#ifdef CONFIG_PTHREAD_MUTEX_BOTH
|
|
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
|
|
/* Include check if this is a NORMAL mutex and that it is robust */
|
|
|
|
if (mutex->pid > 0 &&
|
|
((mutex->flags & _PTHREAD_MFLAGS_ROBUST) != 0 ||
|
|
mutex->type != PTHREAD_MUTEX_NORMAL) &&
|
|
nxsched_get_tcb(mutex->pid) == NULL)
|
|
|
|
#else /* CONFIG_PTHREAD_MUTEX_TYPES */
|
|
/* This can only be a NORMAL mutex. Include check if it is robust */
|
|
|
|
if (mutex->pid > 0 &&
|
|
(mutex->flags & _PTHREAD_MFLAGS_ROBUST) != 0 &&
|
|
nxsched_get_tcb(mutex->pid) == NULL)
|
|
|
|
#endif /* CONFIG_PTHREAD_MUTEX_TYPES */
|
|
#else /* CONFIG_PTHREAD_MUTEX_ROBUST */
|
|
/* This mutex is always robust, whatever type it is. */
|
|
|
|
if (mutex->pid > 0 && nxsched_get_tcb(mutex->pid) == NULL)
|
|
#endif
|
|
{
|
|
DEBUGASSERT(mutex->pid != 0); /* < 0: available, >0 owned, ==0 error */
|
|
DEBUGASSERT((mutex->flags & _PTHREAD_MFLAGS_INCONSISTENT) != 0);
|
|
|
|
/* A thread holds the mutex, but there is no such thread. POSIX
|
|
* requires that the 'robust' mutex return EOWNERDEAD in this
|
|
* case. It is then the caller's responsibility to call
|
|
* pthread_mutex_consistent() to fix the mutex.
|
|
*/
|
|
|
|
mutex->flags |= _PTHREAD_MFLAGS_INCONSISTENT;
|
|
ret = EOWNERDEAD;
|
|
}
|
|
else
|
|
#endif /* !CONFIG_PTHREAD_MUTEX_UNSAFE */
|
|
|
|
{
|
|
/* Take the underlying semaphore, waiting if necessary. NOTE that
|
|
* is required to deadlock for the case of the non-robust NORMAL
|
|
* or default mutex.
|
|
*/
|
|
|
|
ret = pthread_mutex_take(mutex, abs_timeout, true);
|
|
|
|
/* If we successfully obtained the semaphore, then indicate
|
|
* that we own it.
|
|
*/
|
|
|
|
if (ret == OK)
|
|
{
|
|
mutex->pid = mypid;
|
|
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
|
|
mutex->nlocks = 1;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
sched_unlock();
|
|
}
|
|
|
|
sinfo("Returning %d\n", ret);
|
|
return ret;
|
|
}
|