/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup POSIXAPI
*
* @brief System Generates Signal for process after realtime seconds elapsed
*/
/*
* 3.4.1 Schedule Alarm, P1003.1b-1993, p. 79
*/
/* COPYRIGHT (c) 1989-2013.
* On-Line Applications Research Corporation (OAR).
*
* 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.
*
* 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.
*/
#ifdef 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;
}