86 lines
2.3 KiB
C
86 lines
2.3 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 Reutner-Fischer <busybox@busybox.net>
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* Copyright (C) 2008 Darius Augulis <augulis.darius@gmail.com>
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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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#include "linux/types.h" /* for __u32 */
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#include "linux/watchdog.h"
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#define OPT_FOREGROUND (1 << 0)
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#define OPT_STIMER (1 << 1)
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#define OPT_HTIMER (1 << 2)
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static void watchdog_shutdown(int sig UNUSED_PARAM)
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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(EXIT_SUCCESS);
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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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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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unsigned opts;
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unsigned stimer_duration; /* how often to restart */
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unsigned htimer_duration = 60000; /* reboots after N ms if not restarted */
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char *st_arg;
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char *ht_arg;
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opt_complementary = "=1"; /* must have exactly 1 argument */
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opts = getopt32(argv, "Ft:T:", &st_arg, &ht_arg);
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if (opts & OPT_HTIMER)
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htimer_duration = xatou_sfx(ht_arg, suffixes);
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stimer_duration = htimer_duration / 2;
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if (opts & OPT_STIMER)
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stimer_duration = xatou_sfx(st_arg, suffixes);
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bb_signals(BB_FATAL_SIGS, 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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/* WDIOC_SETTIMEOUT takes seconds, not milliseconds */
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htimer_duration = htimer_duration / 1000;
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#ifndef WDIOC_SETTIMEOUT
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#error WDIOC_SETTIMEOUT is not defined, cannot compile watchdog applet
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#else
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ioctl_or_warn(3, WDIOC_SETTIMEOUT, &htimer_duration);
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#endif
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#if 0
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ioctl_or_warn(3, WDIOC_GETTIMEOUT, &htimer_duration);
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printf("watchdog: SW timer is %dms, HW timer is %dms\n",
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stimer_duration, htimer_duration * 1000);
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#endif
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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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while (1) {
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/*
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* Make sure we clear the counter before sleeping,
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* as the counter value 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(stimer_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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