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-rw-r--r--busybox/miscutils/watchdog.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/busybox/miscutils/watchdog.c b/busybox/miscutils/watchdog.c
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1/* vi: set sw=4 ts=4: */
2/*
3 * Mini watchdog implementation for busybox
4 *
5 * Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 */
22
23#include <stdio.h>
24#include <fcntl.h>
25#include <unistd.h>
26#include <stdlib.h>
27#include <signal.h>
28#include "busybox.h"
29
30/* Userspace timer duration, in seconds */
31static unsigned int timer_duration = 30;
32
33/* Watchdog file descriptor */
34static int fd;
35
36static void watchdog_shutdown(int unused)
37{
38 write(fd, "V", 1); /* Magic */
39 close(fd);
40 exit(0);
41}
42
43extern int watchdog_main(int argc, char **argv)
44{
45 int opt;
46
47 while ((opt = getopt(argc, argv, "t:")) > 0) {
48 switch (opt) {
49 case 't':
50 timer_duration = bb_xgetlarg(optarg, 10, 0, INT_MAX);
51 break;
52 default:
53 bb_show_usage();
54 }
55 }
56
57 /* We're only interested in the watchdog device .. */
58 if (optind < argc - 1 || argc == 1)
59 bb_show_usage();
60
61 if (daemon(0, 1) < 0)
62 bb_perror_msg_and_die("Failed forking watchdog daemon");
63
64 signal(SIGHUP, watchdog_shutdown);
65 signal(SIGINT, watchdog_shutdown);
66
67 fd = bb_xopen(argv[argc - 1], O_WRONLY);
68
69 while (1) {
70 /*
71 * Make sure we clear the counter before sleeping, as the counter value
72 * is undefined at this point -- PFM
73 */
74 write(fd, "\0", 1);
75 sleep(timer_duration);
76 }
77
78 watchdog_shutdown(0);
79
80 return EXIT_SUCCESS;
81}