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/****************************************************************************
* sched/signal/sig/nanosleep.c
*
* Copyright (C) 2013 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 <time.h>
#include <signal.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/clock.h>
#include <arch/irq.h>
#include "clock/clock.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nanosleep
*
* Description:
* The nanosleep() function causes the current thread to be suspended from
* execution until either the time interval specified by the rqtp argument
* has elapsed or a signal is delivered to the calling thread and its
* action is to invoke a signal-catching function or to terminate the
* process. The suspension time may be longer than requested because the
* argument value is rounded up to an integer multiple of the sleep
* resolution or because of the scheduling of other activity by the
* system. But, except for the case of being interrupted by a signal, the
* suspension time will not be less than the time specified by rqtp, as
* measured by the system clock, CLOCK_REALTIME.
*
* The use of the nanosleep() function has no effect on the action or
* blockage of any signal.
*
* Parameters:
* rqtp - The amount of time to be suspended from execution.
* rmtp - If the rmtp argument is non-NULL, the timespec structure
* referenced by it is updated to contain the amount of time
* remaining in the interval (the requested time minus the time
* actually slept)
*
* Returned Value:
* If the nanosleep() function returns because the requested time has
* elapsed, its return value is zero.
*
* If the nanosleep() function returns because it has been interrupted by
* a signal, the function returns a value of -1 and sets errno to indicate
* the interruption. If the rmtp argument is non-NULL, the timespec
* structure referenced by it is updated to contain the amount of time
* remaining in the interval (the requested time minus the time actually
* slept). If the rmtp argument is NULL, the remaining time is not
* returned.
*
* If nanosleep() fails, it returns a value of -1 and sets errno to
* indicate the error. The nanosleep() function will fail if:
*
* EINTR - The nanosleep() function was interrupted by a signal.
* EINVAL - The rqtp argument specified a nanosecond value less than
* zero or greater than or equal to 1000 million.
* ENOSYS - The nanosleep() function is not supported by this
* implementation.
*
****************************************************************************/
int nanosleep(FAR const struct timespec *rqtp, FAR struct timespec *rmtp)
{
irqstate_t flags;
uint32_t starttick;
sigset_t set;
struct siginfo value;
int errval;
#ifdef CONFIG_DEBUG /* Warning avoidance */
int ret;
#endif
if (!rqtp || rqtp->tv_nsec < 0 || rqtp->tv_nsec >= 1000000000)
{
errval = EINVAL;
goto errout;
}
/* Get the start time of the wait. Interrupts are disabled to prevent
* timer interrupts while we do tick-related calculations before and
* after the wait.
*/
flags = irqsave();
starttick = clock_systimer();
/* Set up for the sleep. Using the empty set means that we are not
* waiting for any particular signal. However, any unmasked signal can
* still awaken sigtimedwait().
*/
(void)sigemptyset(&set);
/* nanosleep is a simple application of sigtimedwait. */
#ifdef CONFIG_DEBUG /* Warning avoidance */
ret = sigtimedwait(&set, &value, rqtp);
#else
(void)sigtimedwait(&set, &value, rqtp);
#endif
/* sigtimedwait() cannot succeed. It should always return error with
* either (1) EAGAIN meaning that the timeout occurred, or (2) EINTR
* meaning that some other unblocked signal was caught.
*/
errval = get_errno();
DEBUGASSERT(ret < 0 && (errval == EAGAIN || errval == EINTR));
if (errval == EAGAIN)
{
/* The timeout "error" is the normal, successful result */
irqrestore(flags);
return OK;
}
/* If we get there, the wait has failed because we were awakened by a
* signal. Return the amount of "unwaited" time if rmtp is non-NULL.
*/
if (rmtp)
{
uint32_t elapsed;
uint32_t remaining;
int ticks;
/* First get the number of clock ticks that we were requested to
* wait.
*/
(void)clock_time2ticks(rqtp, &ticks);
/* Get the number of ticks that we actually waited */
elapsed = clock_systimer() - starttick;
/* The difference between the number of ticks that we were requested
* to wait and the number of ticks that we actualy waited is that
* amount of time that we failed to wait.
*/
if (elapsed >= (uint32_t)ticks)
{
remaining = 0;
}
else
{
remaining = (uint32_t)ticks - elapsed;
}
(void)clock_ticks2time((int)remaining, rmtp);
}
irqrestore(flags);
errout:
set_errno(errval);
return ERROR;
}
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