287 lines
9.2 KiB
C
287 lines
9.2 KiB
C
/****************************************************************************
|
|
* sched/semaphore/sem_clockwait.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 <stdint.h>
|
|
#include <unistd.h>
|
|
#include <time.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/irq.h>
|
|
#include <nuttx/arch.h>
|
|
#include <nuttx/wdog.h>
|
|
#include <nuttx/cancelpt.h>
|
|
|
|
#include "sched/sched.h"
|
|
#include "clock/clock.h"
|
|
#include "semaphore/semaphore.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: nxsem_clockwait
|
|
*
|
|
* Description:
|
|
* This function will lock the semaphore referenced by sem as in the
|
|
* sem_wait() function. However, if the semaphore cannot be locked without
|
|
* waiting for another process or thread to unlock the semaphore by
|
|
* performing a sem_post() function, this wait will be terminated when the
|
|
* specified timeout expires.
|
|
*
|
|
* The timeout will expire when the absolute time specified by abstime
|
|
* passes, as measured by the clock on which timeouts are based (that is,
|
|
* when the value of that clock equals or exceeds abstime), or if the
|
|
* absolute time specified by abstime has already been passed at the
|
|
* time of the call.
|
|
*
|
|
* This is an internal OS interface. It is functionally equivalent to
|
|
* sem_wait except that:
|
|
*
|
|
* - It is not a cancellation point, and
|
|
* - It does not modify the errno value.
|
|
*
|
|
* Input Parameters:
|
|
* sem - Semaphore object
|
|
* clockid - The timing source to use in the conversion
|
|
* abstime - The absolute time to wait until a timeout is declared.
|
|
*
|
|
* Returned Value:
|
|
* This is an internal OS interface and should not be used by applications.
|
|
* It follows the NuttX internal error return policy: Zero (OK) is
|
|
* returned on success. A negated errno value is returned on failure.
|
|
* That may be one of:
|
|
*
|
|
* EINVAL The sem argument does not refer to a valid semaphore. Or the
|
|
* thread would have blocked, and the abstime parameter specified
|
|
* a nanoseconds field value less than zero or greater than or
|
|
* equal to 1000 million.
|
|
* ETIMEDOUT The semaphore could not be locked before the specified timeout
|
|
* expired.
|
|
* EDEADLK A deadlock condition was detected.
|
|
* EINTR A signal interrupted this function.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int nxsem_clockwait(FAR sem_t *sem, clockid_t clockid,
|
|
FAR const struct timespec *abstime)
|
|
{
|
|
FAR struct tcb_s *rtcb = this_task();
|
|
irqstate_t flags;
|
|
sclock_t ticks;
|
|
int status;
|
|
int ret = ERROR;
|
|
|
|
DEBUGASSERT(up_interrupt_context() == false);
|
|
|
|
/* Verify the input parameters and, in case of an error, set
|
|
* errno appropriately.
|
|
*/
|
|
|
|
#ifdef CONFIG_DEBUG_FEATURES
|
|
if (!abstime || !sem)
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
#endif
|
|
|
|
/* We will disable interrupts until we have completed the semaphore
|
|
* wait. We need to do this (as opposed to just disabling pre-emption)
|
|
* because there could be interrupt handlers that are asynchronously
|
|
* posting semaphores and to prevent race conditions with watchdog
|
|
* timeout. This is not too bad because interrupts will be re-
|
|
* enabled while we are blocked waiting for the semaphore.
|
|
*/
|
|
|
|
flags = enter_critical_section();
|
|
|
|
/* Try to take the semaphore without waiting. */
|
|
|
|
ret = nxsem_trywait(sem);
|
|
if (ret == OK)
|
|
{
|
|
/* We got it! */
|
|
|
|
goto out;
|
|
}
|
|
|
|
/* We will have to wait for the semaphore. Make sure that we were provided
|
|
* with a valid timeout.
|
|
*/
|
|
|
|
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
|
|
{
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* Convert the timespec to clock ticks. We must have interrupts
|
|
* disabled here so that this time stays valid until the wait begins.
|
|
*
|
|
* clock_abstime2ticks() returns zero on success or a POSITIVE errno
|
|
* value on failure.
|
|
*/
|
|
|
|
status = clock_abstime2ticks(clockid, abstime, &ticks);
|
|
|
|
/* If the time has already expired return immediately. */
|
|
|
|
if (status == OK && ticks <= 0)
|
|
{
|
|
ret = -ETIMEDOUT;
|
|
goto out;
|
|
}
|
|
|
|
/* Handle any time-related errors */
|
|
|
|
if (status != OK)
|
|
{
|
|
ret = -status;
|
|
goto out;
|
|
}
|
|
|
|
/* Start the watchdog */
|
|
|
|
wd_start(&rtcb->waitdog, ticks, nxsem_timeout, getpid());
|
|
|
|
/* Now perform the blocking wait. If nxsem_wait() fails, the
|
|
* negated errno value will be returned below.
|
|
*/
|
|
|
|
ret = nxsem_wait(sem);
|
|
|
|
/* Stop the watchdog timer */
|
|
|
|
wd_cancel(&rtcb->waitdog);
|
|
|
|
/* We can now restore interrupts and delete the watchdog */
|
|
|
|
out:
|
|
leave_critical_section(flags);
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: nxsem_clockwait_uninterruptible
|
|
*
|
|
* Description:
|
|
* This function is wrapped version of nxsem_timedwait(), which is
|
|
* uninterruptible and convenient for use.
|
|
*
|
|
* Input Parameters:
|
|
* sem - Semaphore object
|
|
* clockid - The timing source to use in the conversion
|
|
* abstime - The absolute time to wait until a timeout is declared.
|
|
*
|
|
* Returned Value:
|
|
* EINVAL The sem argument does not refer to a valid semaphore. Or the
|
|
* thread would have blocked, and the abstime parameter specified
|
|
* a nanoseconds field value less than zero or greater than or
|
|
* equal to 1000 million.
|
|
* ETIMEDOUT The semaphore could not be locked before the specified timeout
|
|
* expired.
|
|
* EDEADLK A deadlock condition was detected.
|
|
* ECANCELED May be returned if the thread is canceled while waiting.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int nxsem_clockwait_uninterruptible(FAR sem_t *sem, clockid_t clockid,
|
|
FAR const struct timespec *abstime)
|
|
{
|
|
int ret;
|
|
|
|
do
|
|
{
|
|
/* Take the semaphore (perhaps waiting) */
|
|
|
|
ret = nxsem_clockwait(sem, clockid, abstime);
|
|
}
|
|
while (ret == -EINTR);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: sem_clockwait
|
|
*
|
|
* Description:
|
|
* This function will lock the semaphore referenced by sem as in the
|
|
* sem_wait() function. However, if the semaphore cannot be locked without
|
|
* waiting for another process or thread to unlock the semaphore by
|
|
* performing a sem_post() function, this wait will be terminated when the
|
|
* specified timeout expires.
|
|
*
|
|
* The timeout will expire when the absolute time specified by abstime
|
|
* passes, as measured by the clock on which timeouts are based (that is,
|
|
* when the value of that clock equals or exceeds abstime), or if the
|
|
* absolute time specified by abstime has already been passed at the
|
|
* time of the call.
|
|
*
|
|
* Input Parameters:
|
|
* sem - Semaphore object
|
|
* clockid - The timing source to use in the conversion
|
|
* abstime - The absolute time to wait until a timeout is declared.
|
|
*
|
|
* Returned Value:
|
|
* Zero (OK) is returned on success. On failure, -1 (ERROR) is returned
|
|
* and the errno is set appropriately:
|
|
*
|
|
* EINVAL The sem argument does not refer to a valid semaphore. Or the
|
|
* thread would have blocked, and the abstime parameter specified
|
|
* a nanoseconds field value less than zero or greater than or
|
|
* equal to 1000 million.
|
|
* ETIMEDOUT The semaphore could not be locked before the specified timeout
|
|
* expired.
|
|
* EDEADLK A deadlock condition was detected.
|
|
* EINTR A signal interrupted this function.
|
|
* ECANCELED May be returned if the thread is canceled while waiting.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int sem_clockwait(FAR sem_t *sem, clockid_t clockid,
|
|
FAR const struct timespec *abstime)
|
|
{
|
|
int ret;
|
|
|
|
/* sem_timedwait() is a cancellation point */
|
|
|
|
enter_cancellation_point();
|
|
|
|
/* Let nxsem_timedout() do the work */
|
|
|
|
ret = nxsem_clockwait(sem, clockid, abstime);
|
|
if (ret < 0)
|
|
{
|
|
set_errno(-ret);
|
|
ret = ERROR;
|
|
}
|
|
|
|
leave_cancellation_point();
|
|
return ret;
|
|
}
|