208 lines
7.2 KiB
C
208 lines
7.2 KiB
C
/****************************************************************************
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* sched/signal/sig/nanosleep.c
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*
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* Copyright (C) 2013, 2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 <time.h>
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#include <signal.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/clock.h>
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#include <nuttx/irq.h>
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#include "clock/clock.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nanosleep
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*
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* Description:
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* The nanosleep() function causes the current thread to be suspended from
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* execution until either the time interval specified by the rqtp argument
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* has elapsed or a signal is delivered to the calling thread and its
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* action is to invoke a signal-catching function or to terminate the
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* process. The suspension time may be longer than requested because the
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* argument value is rounded up to an integer multiple of the sleep
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* resolution or because of the scheduling of other activity by the
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* system. But, except for the case of being interrupted by a signal, the
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* suspension time will not be less than the time specified by rqtp, as
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* measured by the system clock, CLOCK_REALTIME.
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*
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* The use of the nanosleep() function has no effect on the action or
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* blockage of any signal.
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*
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* Parameters:
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* rqtp - The amount of time to be suspended from execution.
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* rmtp - If the rmtp argument is non-NULL, the timespec structure
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* referenced by it is updated to contain the amount of time
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* remaining in the interval (the requested time minus the time
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* actually slept)
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*
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* Returned Value:
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* If the nanosleep() function returns because the requested time has
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* elapsed, its return value is zero.
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*
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* If the nanosleep() function returns because it has been interrupted by
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* a signal, the function returns a value of -1 and sets errno to indicate
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* the interruption. If the rmtp argument is non-NULL, the timespec
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* structure referenced by it is updated to contain the amount of time
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* remaining in the interval (the requested time minus the time actually
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* slept). If the rmtp argument is NULL, the remaining time is not
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* returned.
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*
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* If nanosleep() fails, it returns a value of -1 and sets errno to
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* indicate the error. The nanosleep() function will fail if:
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*
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* EINTR - The nanosleep() function was interrupted by a signal.
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* EINVAL - The rqtp argument specified a nanosecond value less than
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* zero or greater than or equal to 1000 million.
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* ENOSYS - The nanosleep() function is not supported by this
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* implementation.
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*
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****************************************************************************/
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int nanosleep(FAR const struct timespec *rqtp, FAR struct timespec *rmtp)
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{
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irqstate_t flags;
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systime_t starttick;
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sigset_t set;
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struct siginfo value;
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int errval;
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#ifdef CONFIG_DEBUG_ASSERTIONS /* Warning avoidance */
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int ret;
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#endif
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if (!rqtp || rqtp->tv_nsec < 0 || rqtp->tv_nsec >= 1000000000)
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{
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errval = EINVAL;
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goto errout;
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}
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/* Get the start time of the wait. Interrupts are disabled to prevent
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* timer interrupts while we do tick-related calculations before and
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* after the wait.
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*/
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flags = enter_critical_section();
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starttick = clock_systimer();
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/* Set up for the sleep. Using the empty set means that we are not
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* waiting for any particular signal. However, any unmasked signal can
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* still awaken sigtimedwait().
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*/
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(void)sigemptyset(&set);
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/* nanosleep is a simple application of sigtimedwait. */
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#ifdef CONFIG_DEBUG_ASSERTIONS /* Warning avoidance */
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ret = sigtimedwait(&set, &value, rqtp);
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#else
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(void)sigtimedwait(&set, &value, rqtp);
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#endif
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/* sigtimedwait() cannot succeed. It should always return error with
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* either (1) EAGAIN meaning that the timeout occurred, or (2) EINTR
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* meaning that some other unblocked signal was caught.
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*/
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errval = get_errno();
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DEBUGASSERT(ret < 0 && (errval == EAGAIN || errval == EINTR));
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if (errval == EAGAIN)
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{
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/* The timeout "error" is the normal, successful result */
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leave_critical_section(flags);
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return OK;
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}
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/* If we get there, the wait has failed because we were awakened by a
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* signal. Return the amount of "unwaited" time if rmtp is non-NULL.
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*/
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if (rmtp)
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{
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systime_t elapsed;
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systime_t remaining;
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int ticks;
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/* REVISIT: The conversion from time to ticks and back could
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* be avoided. clock_timespec_subtract() would be used instead
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* to get the time difference.
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*/
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/* First get the number of clock ticks that we were requested to
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* wait.
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*/
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(void)clock_time2ticks(rqtp, &ticks);
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/* Get the number of ticks that we actually waited */
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elapsed = clock_systimer() - starttick;
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/* The difference between the number of ticks that we were requested
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* to wait and the number of ticks that we actualy waited is that
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* amount of time that we failed to wait.
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*/
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if (elapsed >= (uint32_t)ticks)
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{
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remaining = 0;
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}
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else
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{
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remaining = (uint32_t)ticks - elapsed;
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}
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(void)clock_ticks2time((int)remaining, rmtp);
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}
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leave_critical_section(flags);
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errout:
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set_errno(errval);
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return ERROR;
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}
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