/* vi: set sw=4 ts=4: */ /* * Mini watchdog implementation for busybox * * Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <stdio.h> #include <fcntl.h> #include <unistd.h> #include <stdlib.h> #include <signal.h> #include "busybox.h" /* Userspace timer duration, in seconds */ static unsigned int timer_duration = 30; /* Watchdog file descriptor */ static int fd; static void watchdog_shutdown(int unused) { write(fd, "V", 1); /* Magic */ close(fd); exit(0); } extern int watchdog_main(int argc, char **argv) { int opt; while ((opt = getopt(argc, argv, "t:")) > 0) { switch (opt) { case 't': timer_duration = bb_xgetlarg(optarg, 10, 0, INT_MAX); break; default: bb_show_usage(); } } /* We're only interested in the watchdog device .. */ if (optind < argc - 1 || argc == 1) bb_show_usage(); if (daemon(0, 1) < 0) bb_perror_msg_and_die("Failed forking watchdog daemon"); signal(SIGHUP, watchdog_shutdown); signal(SIGINT, watchdog_shutdown); fd = bb_xopen(argv[argc - 1], O_WRONLY); while (1) { /* * Make sure we clear the counter before sleeping, as the counter value * is undefined at this point -- PFM */ write(fd, "\0", 1); sleep(timer_duration); } watchdog_shutdown(0); return EXIT_SUCCESS; }