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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 "libbb.h"
#define OPT_FOREGROUND 0x01
#define OPT_TIMER 0x02
static void watchdog_shutdown(int ATTRIBUTE_UNUSED sig) ATTRIBUTE_NORETURN;
static void watchdog_shutdown(int ATTRIBUTE_UNUSED sig)
{
static const char V = 'V';
write(3, &V, 1); /* Magic, see watchdog-api.txt in kernel */
if (ENABLE_FEATURE_CLEAN_UP)
close(3);
exit(0);
}
int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int watchdog_main(int argc, char **argv)
{
unsigned opts;
unsigned timer_duration = 30000; /* Userspace timer duration, in milliseconds */
char *t_arg;
opt_complementary = "=1"; /* must have 1 argument */
opts = getopt32(argv, "Ft:", &t_arg);
if (opts & OPT_TIMER) {
static const struct suffix_mult suffixes[] = {
{ "ms", 1 },
{ "", 1000 },
{ }
};
timer_duration = xatou_sfx(t_arg, suffixes);
}
if (!(opts & OPT_FOREGROUND)) {
bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
}
signal(SIGHUP, watchdog_shutdown);
signal(SIGINT, watchdog_shutdown);
/* Use known fd # - avoid needing global 'int fd' */
xmove_fd(xopen(argv[argc - 1], O_WRONLY), 3);
while (1) {
/*
* Make sure we clear the counter before sleeping, as the counter value
* is undefined at this point -- PFM
*/
write(3, "", 1); /* write zero byte */
usleep(timer_duration * 1000L);
}
return EXIT_SUCCESS; /* - not reached, but gcc 4.2.1 is too dumb! */
}
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