Lockup Timer

lockup_timer.c

#include "lockup_timer.h"

#define PRINT_ERR(fmt, ...)  \
	fprintf(stderr, "%s:%d:%s(): " fmt, \
		__FILE__, __LINE__, __func__, \
		__VA_ARGS__)

#include <stdio.h>  /* fprintf */

#include <errno.h>  /* errno */
#include <string.h>  /* strerror */

static void
lockup_timer_notifee(union sigval sval)
{
	jmp_buf * buf_p = (jmp_buf *) sval.sival_ptr;
	if (buf_p == NULL)
	{
		PRINT_ERR("sigval is empty");
		return;
	}

	longjmp(*buf_p, 1);
}

int
lockup_timer_create(timer_t * const timer_p, jmp_buf * const jmp_buf_p)
{
	struct sigevent sev = {
// 		.sigev_notify = SIGEV_SIGNAL,
// 		.sigev_signo = SIGALRM,
		.sigev_notify = SIGEV_THREAD,
		.sigev_notify_function = lockup_timer_notifee,
		.sigev_notify_attributes = NULL,
		.sigev_value = { .sival_ptr = jmp_buf_p },
	};

	int is_err = timer_create(CLOCK_REALTIME, &sev, timer_p);
	if ( is_err )
	{
		PRINT_ERR("%s", strerror(errno));
	}

	return is_err ? -errno : 0;
}

int
lockup_timer_delete(timer_t timer)
{
	int is_err = timer_delete(timer);
	if ( is_err )
	{
		PRINT_ERR("%s", strerror(errno));
	}

	return is_err ? -errno : 0;
}

int
lockup_timer_set(timer_t timer, int const sec)
{
	struct itimerspec const timeout = {
		.it_value = {
			.tv_sec = (time_t) sec,
			.tv_nsec = 0,
		},
		.it_interval = { 0 },
	};

	int is_err = timer_settime(timer, 0, &timeout, NULL);
	if ( is_err )
	{
		PRINT_ERR("%s", strerror(errno));
	}

	return is_err ? -errno : 0;
}

int
lockup_timer_disarm(timer_t timer)
{
	return lockup_timer_set(timer, 0);
}

lockup_timer.h

#ifndef LOCKUP_TIMER_H_
#define LOCKUP_TIMER_H_ 1


// for timers support
#if defined(_POSIX_C_SOURCE)
# if (_POSIX_C_SOURCE < 199309L)
#  error "_POSIX_C_SOURCE set too low, at least 199309L required"
# endif
#else
# define _POSIX_C_SOURCE 199309L
#endif


#include <signal.h> /* struct sigevent, union sigval */
#include <time.h> /* timer_create, timer_t */
#include <setjmp.h> /* setjmp, longjmp */


int lockup_timer_create(timer_t * const timer_p, jmp_buf * const jmp_buf_p);
int lockup_timer_delete(timer_t timer);
int lockup_timer_set(timer_t timer, int const sec);
int lockup_timer_disarm(timer_t timer);


#endif // LOCKUP_TIMER_H_