ex1.c

/* Simple example use of libwdog API for the watchdogd process monitor
 *
 * Copyright (c) 2015-2024  Joachim Wiberg <troglobit@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include "wdog.h"

extern char *__progname;
extern int   __wdog_testmode;

#define DEBUG(fmt, args...)  if (dbg) printf("%s: " fmt "\n", __progname, ##args);
#define PERROR(fmt, args...) if (dbg) fprintf(stderr, "%s: " fmt ": %s\n", __progname, ##args, strerror(errno));

int main(int argc, char *argv[])
{
    int id, i, dbg = 0;
    unsigned int ack;

    if (argc >= 2 && !strncmp(argv[1], "-V", 2))
        dbg = 1;

    DEBUG("=> Checking connectivity with watchdogd ...");
    if (wdog_ping()) {
        PERROR("Failed connectivity check");
        return 1;
    }
    DEBUG("=> OK!");

    id = wdog_subscribe(NULL, 3000, &ack);
    if (id < 0) {
        perror("Failed connecting to wdog");
        return 1;
    }

    for (i = 0; i < 20; i++) {
        int enabled = 0;

        if (wdog_status(&enabled))
            PERROR("Failed reading wdog status");

        DEBUG("=> Kicking ack:%u ... (%sABLED)", ack, enabled ? "EN" : "DIS");
        if (wdog_kick2(id, &ack))
            PERROR("Failed kicking");
        sleep(2);

        /* Apx. halfway through, disable wdog ... */
        if (i == 8) {
            DEBUG("=> Verify that wdog can be disabled at runtime.");
            wdog_enable(0);

            /* Miss deadline */
            sleep(3);
        }

        /* Let program kick "in the air" for a few iterations, must work! */

        /* Later on ... re-enable */
        if (i == 14) {
            DEBUG("=> Re-enabling wdog ...");
            wdog_enable(1);
        }
    }

    DEBUG("=> Exiting ...");
    if (wdog_unsubscribe(id, ack)) {
        PERROR("Failed unsubscribe");
        return 1;
    }

    return 0;
}