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/**
* @file
*
* @brief Schedule Alarm
* @ingroup POSIXAPI
*/
/*
* COPYRIGHT (c) 1989-2008.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <signal.h>
#include <unistd.h>
#include <rtems/posix/pthreadimpl.h>
#include <rtems/posix/psignalimpl.h>
#include <rtems/posix/time.h>
#include <rtems/score/threaddispatch.h>
#include <rtems/score/todimpl.h>
#include <rtems/score/watchdogimpl.h>
static void _POSIX_signals_Ualarm_TSR( Objects_Id id, void *argument );
static Watchdog_Control _POSIX_signals_Ualarm_timer = WATCHDOG_INITIALIZER(
_POSIX_signals_Ualarm_TSR,
0,
NULL
);
/*
* _POSIX_signals_Ualarm_TSR
*/
static void _POSIX_signals_Ualarm_TSR(
Objects_Id id __attribute__((unused)),
void *argument __attribute__((unused))
)
{
/*
* Send a SIGALRM but if there is a problem, ignore it.
* It's OK, there isn't a way this should fail.
*/
(void) kill( getpid(), SIGALRM );
/*
* If the reset interval is non-zero, reschedule ourselves.
*/
_Watchdog_Reset_ticks( &_POSIX_signals_Ualarm_timer );
}
useconds_t ualarm(
useconds_t useconds,
useconds_t interval
)
{
useconds_t remaining = 0;
Watchdog_Control *the_timer;
Watchdog_Interval ticks;
Watchdog_States state;
struct timespec tp;
the_timer = &_POSIX_signals_Ualarm_timer;
_Thread_Disable_dispatch();
state = _Watchdog_Remove_ticks( the_timer );
if ( state == WATCHDOG_ACTIVE ) {
/*
* The stop_time and start_time fields are snapshots of ticks since
* boot. Since alarm() is dealing in seconds, we must account for
* this.
*/
ticks = the_timer->initial;
ticks -= (the_timer->stop_time - the_timer->start_time);
/* remaining is now in ticks */
_Timespec_From_ticks( ticks, &tp );
remaining = tp.tv_sec * TOD_MICROSECONDS_PER_SECOND;
remaining += tp.tv_nsec / 1000;
}
/*
* If useconds is non-zero, then the caller wants to schedule
* the alarm repeatedly at that interval. If the interval is
* less than a single clock tick, then fudge it to a clock tick.
*/
if ( useconds ) {
Watchdog_Interval ticks;
tp.tv_sec = useconds / TOD_MICROSECONDS_PER_SECOND;
tp.tv_nsec = (useconds % TOD_MICROSECONDS_PER_SECOND) * 1000;
ticks = _Timespec_To_ticks( &tp );
if ( ticks == 0 )
ticks = 1;
_Watchdog_Insert_ticks( the_timer, _Timespec_To_ticks( &tp ) );
}
_Thread_Enable_dispatch();
return remaining;
}
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