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/* vi: set sw=4 ts=4: */
/*
* Mini watchdog implementation for busybox
*
* Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org>
* Copyright (C) 2006 Bernhard Fischer <busybox@busybox.net>
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
#include "busybox.h"
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
/* Watchdog file descriptor */
static int fd;
static void watchdog_shutdown(int ATTRIBUTE_UNUSED unused)
{
write(fd, "V", 1); /* Magic, see watchdog-api.txt in kernel */
close(fd);
exit(0);
}
int watchdog_main(int argc, char **argv)
{
unsigned long timer_duration = 30; /* Userspace timer duration, in seconds */
char *t_arg;
if (bb_getopt_ulflags(argc, argv, "t:", &t_arg))
timer_duration = bb_xgetlarg(t_arg, 10, 0, INT_MAX);
/* We're only interested in the watchdog device .. */
if (optind < argc - 1 || argc == 1)
bb_show_usage();
#ifdef BB_NOMMU
vfork_daemon(0, 1);
#else
bb_xdaemon(0, 1);
#endif
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;
}
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