nuttx/sched/pthread/pthread_condclockwait.c

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/****************************************************************************
* sched/pthread/pthread_condclockwait.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 <nuttx/compiler.h>
#include <stdint.h>
#include <unistd.h>
#include <pthread.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/wdog.h>
#include <nuttx/signal.h>
#include <nuttx/cancelpt.h>
#include "sched/sched.h"
#include "pthread/pthread.h"
#include "clock/clock.h"
#include "signal/signal.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pthread_cond_clockwait
*
* Description:
* A thread can perform a timed wait on a condition variable.
*
* Input Parameters:
* cond - the condition variable to wait on
* mutex - the mutex that protects the condition variable
* clockid - The timing source to use in the conversion
* abstime - wait until this absolute time
*
* Returned Value:
* OK (0) on success; A non-zero errno value is returned on failure.
*
* Assumptions:
* Timing is of resolution 1 msec, with +/-1 millisecond accuracy.
*
****************************************************************************/
int pthread_cond_clockwait(FAR pthread_cond_t *cond,
FAR pthread_mutex_t *mutex,
clockid_t clockid,
FAR const struct timespec *abstime)
{
irqstate_t flags;
int mypid = gettid();
int ret = OK;
int status;
sinfo("cond=%p mutex=%p abstime=%p\n", cond, mutex, abstime);
/* pthread_cond_clockwait() is a cancellation point */
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enter_cancellation_point();
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/* 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 != mypid)
{
ret = EPERM;
}
/* If no wait time is provided, this function degenerates to
* the same behavior as pthread_cond_wait().
*/
else if (!abstime)
{
ret = pthread_cond_wait(cond, mutex);
}
else
{
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
uint8_t mflags;
#endif
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
uint8_t type;
int16_t nlocks;
#endif
sinfo("Give up mutex...\n");
/* We must disable pre-emption and interrupts here so that
* the time stays valid until the wait begins. This adds
* complexity because we assure that interrupts and
* pre-emption are re-enabled correctly.
*/
sched_lock();
flags = enter_critical_section();
/* Give up the mutex */
mutex->pid = INVALID_PROCESS_ID;
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
mflags = mutex->flags;
#endif
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
type = mutex->type;
nlocks = mutex->nlocks;
#endif
ret = pthread_mutex_give(mutex);
if (ret == 0)
{
status = nxsem_clockwait_uninterruptible(
&cond->sem, clockid, abstime);
if (status < 0)
{
ret = -status;
}
}
/* Restore interrupts (pre-emption will be enabled
* when we fall through the if/then/else)
*/
leave_critical_section(flags);
/* Reacquire the mutex (retaining the ret). */
sinfo("Re-locking...\n");
status = pthread_mutex_take(mutex, NULL, false);
if (status == OK)
{
mutex->pid = mypid;
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
mutex->flags = mflags;
#endif
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
mutex->type = type;
mutex->nlocks = nlocks;
#endif
}
else if (ret == 0)
{
ret = status;
}
/* Re-enable pre-emption (It is expected that interrupts
* have already been re-enabled in the above logic)
*/
sched_unlock();
}
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leave_cancellation_point();
sinfo("Returning %d\n", ret);
return ret;
}