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71 lines
1.5 KiB
C
71 lines
1.5 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini watchdog implementation for busybox
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*
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* Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org>
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* Copyright (C) 2006 Bernhard Fischer <busybox@busybox.net>
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*
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* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
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*/
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#include "busybox.h"
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <signal.h>
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#define OPT_FOREGROUND 0x01
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#define OPT_TIMER 0x02
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/* Watchdog file descriptor */
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static int fd;
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static void watchdog_shutdown(int ATTRIBUTE_UNUSED unused)
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{
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write(fd, "V", 1); /* Magic, see watchdog-api.txt in kernel */
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close(fd);
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exit(0);
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}
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int watchdog_main(int argc, char **argv)
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{
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unsigned long opts;
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unsigned long timer_duration = 30; /* Userspace timer duration, in seconds */
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char *t_arg;
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opts = bb_getopt_ulflags(argc, argv, "Ft:", &t_arg);
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if (opts & OPT_TIMER)
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timer_duration = bb_xgetlarg(t_arg, 10, 0, INT_MAX);
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/* We're only interested in the watchdog device .. */
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if (optind < argc - 1 || argc == 1)
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bb_show_usage();
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#ifdef BB_NOMMU
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if (!(opts & OPT_FOREGROUND))
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vfork_daemon_rexec(0, 1, argc, argv, "-F");
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#else
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bb_xdaemon(0, 1);
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#endif
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signal(SIGHUP, watchdog_shutdown);
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signal(SIGINT, watchdog_shutdown);
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fd = bb_xopen(argv[argc - 1], O_WRONLY);
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while (1) {
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/*
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* Make sure we clear the counter before sleeping, as the counter value
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* is undefined at this point -- PFM
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*/
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write(fd, "\0", 1);
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sleep(timer_duration);
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}
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watchdog_shutdown(0);
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return EXIT_SUCCESS;
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}
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