nuttx/sched/signal/sig_nanosleep.c

339 lines
13 KiB
C

/****************************************************************************
* sched/signal/sig/nanosleep.c
*
* Copyright (C) 2013, 2016-2017 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 <nuttx/irq.h>
#include <nuttx/signal.h>
#include <nuttx/cancelpt.h>
#include "clock/clock.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxsig_nanosleep
*
* Description:
* The nxsig_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 nxsig_nanosleep() function has no effect on the action
* or blockage of any signal.
*
* Input 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 nxsig_nanosleep() function returns because the requested time
* has elapsed, its return value is zero.
*
* If the nxsig_nanosleep() function returns because it has been
* interrupted by a signal, the function returns a negated errno value
* 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 nxsig_nanosleep() fails, it returns a negated errno indicating the
* cause of the failure. The nxsig_nanosleep() function will fail if:
*
* EINTR - The nxsig_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 nxsig_nanosleep() function is not supported by this
* implementation.
*
****************************************************************************/
int nxsig_nanosleep(FAR const struct timespec *rqtp,
FAR struct timespec *rmtp)
{
irqstate_t flags;
clock_t starttick;
sigset_t set;
int ret;
/* Sanity check */
if (rqtp == NULL || rqtp->tv_nsec < 0 || rqtp->tv_nsec >= 1000000000)
{
return -EINVAL;
}
/* 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 = enter_critical_section();
starttick = clock_systime_ticks();
/* 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 nxsig_timedwait().
*/
sigemptyset(&set);
/* nxsig_nanosleep is a simple application of nxsig_timedwait. */
ret = nxsig_timedwait(&set, NULL, rqtp);
/* nxsig_timedwait() 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.
*/
if (ret == -EAGAIN)
{
/* The timeout "error" is the normal, successful result */
leave_critical_section(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)
{
clock_t elapsed;
clock_t remaining;
sclock_t ticks;
/* REVISIT: The conversion from time to ticks and back could
* be avoided. clock_timespec_subtract() would be used instead
* to get the time difference.
*/
/* First get the number of clock ticks that we were requested to
* wait.
*/
clock_time2ticks(rqtp, &ticks);
/* Get the number of ticks that we actually waited */
elapsed = clock_systime_ticks() - starttick;
/* The difference between the number of ticks that we were requested
* to wait and the number of ticks that we actually waited is that
* amount of time that we failed to wait.
*/
if (elapsed >= (clock_t)ticks)
{
remaining = 0;
}
else
{
remaining = (clock_t)ticks - elapsed;
}
clock_ticks2time((sclock_t)remaining, rmtp);
}
leave_critical_section(flags);
return ret;
}
/****************************************************************************
* Name: clock_nanosleep
*
* Description:
* If the flag TIMER_ABSTIME is not set in the flags argument, the
* clock_nanosleep() function will cause 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 the process
* is terminated. The clock used to measure the time will be the clock
* specified by clock_id.
*
* If the flag TIMER_ABSTIME is set in the flags argument, the
* clock_nanosleep() function will cause the current thread to be
* suspended from execution until either the time value of the clock
* specified by clock_id reaches the absolute time specified by the rqtp
* argument, or a signal is delivered to the calling thread and its action
* is to invoke a signal-catching function, or the process is terminated.
* If, at the time of the call, the time value specified by rqtp is less
* than or equal to the time value of the specified clock, then
* clock_nanosleep() will return immediately and the calling process will
* not be suspended.
*
* The suspension time caused by this function 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 for the relative clock_nanosleep() function (that is,
* with the TIMER_ABSTIME flag not set) will not be less than the time
* interval specified by rqtp, as measured by the corresponding clock. The
* suspension for the absolute clock_nanosleep() function (that is, with
* the TIMER_ABSTIME flag set) will be in effect at least until the value
* of the corresponding clock reaches the absolute time specified by rqtp,
* except for the case of being interrupted by a signal.
*
* The use of the clock_nanosleep() function will have no effect on the
* action or blockage of any signal.
*
* The clock_nanosleep() function will fail if the clock_id argument refers
* to the CPU-time clock of the calling thread. It is unspecified whether
* clock_id values of other CPU-time clocks are allowed.
*
* Input Parameters:
* clockid - The clock to use to interpret the absolute time
* flags - Open flags. TIMER_ABSTIME is the only supported flag.
* 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 clock_nanosleep() function returns because the requested time has
* elapsed, its return value is zero.
*
* If the clock_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 clock_nanosleep() fails, it returns a value of -1 and sets errno to
* indicate the error. The clock_nanosleep() function will fail if:
*
* EINTR - The clock_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 clock_nanosleep() function is not supported by this
* implementation.
*
****************************************************************************/
int clock_nanosleep(clockid_t clockid, int flags,
FAR const struct timespec *rqtp,
FAR struct timespec *rmtp)
{
int ret;
/* clock_nanosleep() is a cancellation point */
enter_cancellation_point();
/* Check if absolute time is selected */
if ((flags & TIMER_ABSTIME) != 0)
{
struct timespec reltime;
struct timespec now;
irqstate_t irqstate;
/* Calculate the relative time delay. We need to enter a critical
* section early to assure the relative time is valid from this
* point in time.
*/
irqstate = enter_critical_section();
ret = clock_gettime(clockid, &now);
if (ret < 0)
{
/* clock_gettime() sets the errno variable */
leave_critical_section(irqstate);
leave_cancellation_point();
return ERROR;
}
clock_timespec_subtract(rqtp, &now, &reltime);
/* Now that we have the relative time, the remaining operations
* are equivalent to nxsig_nanosleep().
*/
ret = nxsig_nanosleep(&reltime, rmtp);
leave_critical_section(irqstate);
}
else
{
/* In the relative time case, clock_nanosleep() is equivalent to
* nanosleep. In this case, it is a paper thin wrapper around
* nxsig_nanosleep().
*/
ret = nxsig_nanosleep(rqtp, rmtp);
}
/* Check if nxsig_nanosleep() succeeded */
if (ret < 0)
{
/* If not set the errno variable and return -1 */
set_errno(-ret);
ret = ERROR;
}
leave_cancellation_point();
return ret;
}