* Mini watchdog implementation for busybox
*
* Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org>
- * Copyright (C) 2006 Bernhard Fischer <busybox@busybox.net>
+ * Copyright (C) 2006 Bernhard Reutner-Fischer <busybox@busybox.net>
+ * Copyright (C) 2008 Darius Augulis <augulis.darius@gmail.com>
*
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+//config:config WATCHDOG
+//config: bool "watchdog (5.1 kb)"
+//config: default y
+//config: select PLATFORM_LINUX
+//config: help
+//config: The watchdog utility is used with hardware or software watchdog
+//config: device drivers. It opens the specified watchdog device special file
+//config: and periodically writes a magic character to the device. If the
+//config: watchdog applet ever fails to write the magic character within a
+//config: certain amount of time, the watchdog device assumes the system has
+//config: hung, and will cause the hardware to reboot.
+
+//applet:IF_WATCHDOG(APPLET(watchdog, BB_DIR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_WATCHDOG) += watchdog.o
+
+//usage:#define watchdog_trivial_usage
+//usage: "[-t N[ms]] [-T N[ms]] [-F] DEV"
+//usage:#define watchdog_full_usage "\n\n"
+//usage: "Periodically write to watchdog device DEV\n"
+//usage: "\n -T N Reboot after N seconds if not reset (default 60)"
+//usage: "\n -t N Reset every N seconds (default 30)"
+//usage: "\n -F Run in foreground"
+//usage: "\n"
+//usage: "\nUse 500ms to specify period in milliseconds"
#include "libbb.h"
+#include <linux/types.h> /* for __u32 */
+#include <linux/watchdog.h>
-#define OPT_FOREGROUND 0x01
-#define OPT_TIMER 0x02
+#ifndef WDIOC_SETOPTIONS
+# define WDIOC_SETOPTIONS 0x5704
+#endif
+#ifndef WDIOC_SETTIMEOUT
+# define WDIOC_SETTIMEOUT 0x5706
+#endif
+#ifndef WDIOC_GETTIMEOUT
+# define WDIOC_GETTIMEOUT 0x5707
+#endif
+#ifndef WDIOS_ENABLECARD
+# define WDIOS_ENABLECARD 2
+#endif
-static void watchdog_shutdown(int sig ATTRIBUTE_UNUSED)
+#define OPT_FOREGROUND (1 << 0)
+#define OPT_STIMER (1 << 1)
+#define OPT_HTIMER (1 << 2)
+
+static void shutdown_watchdog(void)
{
static const char V = 'V';
+ write(3, &V, 1); /* Magic, see watchdog-api.txt in kernel */
+ close(3);
+}
+
+static void shutdown_on_signal(int sig UNUSED_PARAM)
+{
+ remove_pidfile(CONFIG_PID_FILE_PATH "/watchdog.pid");
+ shutdown_watchdog();
+ _exit(EXIT_SUCCESS);
+}
+
+static void watchdog_open(const char* device)
+{
+ /* Use known fd # - avoid needing global 'int fd' */
+ xmove_fd(xopen(device, O_WRONLY), 3);
+
+ /* If the watchdog driver can do something other than cause a reboot
+ * on a timeout, then it's possible this program may be starting from
+ * a state when the watchdog hadn't been previously stopped with
+ * the magic write followed by a close. In this case the driver may
+ * not start properly, so always do the proper stop first just in case.
+ */
+ shutdown_watchdog();
- write(3, &V, 1); /* Magic, see watchdog-api.txt in kernel */
- if (ENABLE_FEATURE_CLEAN_UP)
- close(3);
- exit(EXIT_SUCCESS);
+ xmove_fd(xopen(device, O_WRONLY), 3);
}
int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int watchdog_main(int argc, char **argv)
+int watchdog_main(int argc UNUSED_PARAM, char **argv)
{
+ static const int enable = WDIOS_ENABLECARD;
+ static const struct suffix_mult suffixes[] = {
+ { "ms", 1 },
+ { "", 1000 },
+ { "", 0 }
+ };
+
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);
- }
+ unsigned stimer_duration; /* how often to restart */
+ unsigned htimer_duration = 60000; /* reboots after N ms if not restarted */
+ char *st_arg;
+ char *ht_arg;
+
+ opt_complementary = "=1"; /* must have exactly 1 argument */
+ opts = getopt32(argv, "Ft:T:", &st_arg, &ht_arg);
- if (!(opts & OPT_FOREGROUND)) {
+ /* We need to daemonize *before* opening the watchdog as many drivers
+ * will only allow one process at a time to do so. Since daemonizing
+ * is not perfect (child may run before parent finishes exiting), we
+ * can't rely on parent exiting before us (let alone *cleanly* releasing
+ * the watchdog fd -- something else that may not even be allowed).
+ */
+ if (!(opts & OPT_FOREGROUND))
bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
- }
- bb_signals(BB_FATAL_SIGS, watchdog_shutdown);
+ /* maybe bb_logenv_override(); here for LOGGING=syslog to work? */
- /* Use known fd # - avoid needing global 'int fd' */
- xmove_fd(xopen(argv[argc - 1], O_WRONLY), 3);
+ if (opts & OPT_HTIMER)
+ htimer_duration = xatou_sfx(ht_arg, suffixes);
+ stimer_duration = htimer_duration / 2;
+ if (opts & OPT_STIMER)
+ stimer_duration = xatou_sfx(st_arg, suffixes);
+
+ bb_signals(BB_FATAL_SIGS, shutdown_on_signal);
+
+ watchdog_open(argv[optind]);
+
+ /* WDIOC_SETTIMEOUT takes seconds, not milliseconds */
+ htimer_duration = htimer_duration / 1000;
+ ioctl_or_warn(3, WDIOC_SETOPTIONS, (void*) &enable);
+ ioctl_or_warn(3, WDIOC_SETTIMEOUT, &htimer_duration);
+#if 0
+ ioctl_or_warn(3, WDIOC_GETTIMEOUT, &htimer_duration);
+ printf("watchdog: SW timer is %dms, HW timer is %ds\n",
+ stimer_duration, htimer_duration * 1000);
+#endif
-// TODO?
-// if (!(opts & OPT_TIMER)) {
-// if (ioctl(fd, WDIOC_GETTIMEOUT, &timer_duration) == 0)
-// timer_duration *= 500;
-// else
-// timer_duration = 30000;
-// }
+ write_pidfile(CONFIG_PID_FILE_PATH "/watchdog.pid");
while (1) {
/*
- * Make sure we clear the counter before sleeping, as the counter value
- * is undefined at this point -- PFM
+ * 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);
+ usleep(stimer_duration * 1000L);
}
return EXIT_SUCCESS; /* - not reached, but gcc 4.2.1 is too dumb! */
}
projects / oweals / busybox.git / blobdiff