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