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/**
* @file
*
* @brief System Generates Signal for process after realtime seconds elapsed
* @ingroup POSIXAPI
*/
/*
* 3.4.1 Schedule Alarm, P1003.1b-1993, p. 79
*/
/* COPYRIGHT (c) 1989-2013.
* 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 <unistd.h>
#include <signal.h>
#include <rtems/score/todimpl.h>
#include <rtems/score/watchdogimpl.h>
ISR_LOCK_DEFINE( static, _POSIX_signals_Alarm_lock, "POSIX Alarm" )
static void _POSIX_signals_Alarm_TSR( Watchdog_Control *the_watchdog )
{
int status;
status = kill( getpid(), SIGALRM );
#if defined(RTEMS_DEBUG)
/*
* There is no reason to think this might fail but we should be
* cautious.
*/
_Assert(status == 0);
#else
(void) status;
#endif
}
static Watchdog_Control _POSIX_signals_Alarm_watchdog = WATCHDOG_INITIALIZER(
_POSIX_signals_Alarm_TSR
);
unsigned int alarm(
unsigned int seconds
)
{
unsigned int remaining;
Watchdog_Control *the_watchdog;
ISR_lock_Context lock_context;
ISR_lock_Context lock_context2;
Per_CPU_Control *cpu;
uint64_t now;
uint32_t ticks_per_second;
uint32_t ticks;
the_watchdog = &_POSIX_signals_Alarm_watchdog;
ticks_per_second = TOD_TICKS_PER_SECOND;
ticks = seconds * ticks_per_second;
_ISR_lock_ISR_disable_and_acquire(
&_POSIX_signals_Alarm_lock,
&lock_context
);
cpu = _Watchdog_Get_CPU( the_watchdog );
_Watchdog_Per_CPU_acquire_critical( cpu, &lock_context2 );
now = cpu->Watchdog.ticks;
remaining = (unsigned long) _Watchdog_Cancel(
&cpu->Watchdog.Header[ PER_CPU_WATCHDOG_TICKS ],
the_watchdog,
now
);
if ( ticks != 0 ) {
_Watchdog_Insert(
&cpu->Watchdog.Header[ PER_CPU_WATCHDOG_TICKS ],
the_watchdog,
now + ticks
);
}
_Watchdog_Per_CPU_release_critical( cpu, &lock_context2 );
_ISR_lock_Release_and_ISR_enable(
&_POSIX_signals_Alarm_lock,
&lock_context
);
return ( remaining + ticks_per_second - 1 ) / ticks_per_second;
}
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