rdate: make it do something remotely sane, facing 32-bit time overflow

[oweals/busybox.git] / miscutils / watchdog.c

diff --git a/miscutils/watchdog.c b/miscutils/watchdog.c
index 75a399f24ed64b0414057466aa6542aa284f4d6a..07ae64e52afbae01f090a6e7c01d6b34018b84bb 100644 (file)
--- a/miscutils/watchdog.c
+++ b/miscutils/watchdog.c
@@ -6,10 +6,36 @@
  * 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"
+//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  (1 << 0)
@@ -20,10 +46,11 @@ static void watchdog_shutdown(int sig UNUSED_PARAM)
 {
        static const char V = 'V';
 
-       write(3, &V, 1);        /* Magic, see watchdog-api.txt in kernel */
+       remove_pidfile(CONFIG_PID_FILE_PATH "/watchdog.pid");
+       write(3, &V, 1);  /* Magic, see watchdog-api.txt in kernel */
        if (ENABLE_FEATURE_CLEAN_UP)
                close(3);
-       exit(EXIT_SUCCESS);
+       _exit(EXIT_SUCCESS);
 }
 
 int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -32,7 +59,7 @@ int watchdog_main(int argc, char **argv)
        static const struct suffix_mult suffixes[] = {
                { "ms", 1 },
                { "", 1000 },
-               { }
+               { "", 0 }
        };
 
        unsigned opts;
@@ -44,6 +71,15 @@ int watchdog_main(int argc, char **argv)
        opt_complementary = "=1"; /* must have exactly 1 argument */
        opts = getopt32(argv, "Ft:T:", &st_arg, &ht_arg);
 
+       /* 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);
+
        if (opts & OPT_HTIMER)
                htimer_duration = xatou_sfx(ht_arg, suffixes);
        stimer_duration = htimer_duration / 2;
@@ -57,21 +93,30 @@ int watchdog_main(int argc, char **argv)
 
        /* WDIOC_SETTIMEOUT takes seconds, not milliseconds */
        htimer_duration = htimer_duration / 1000;
+#ifndef WDIOC_SETTIMEOUT
+# error WDIOC_SETTIMEOUT is not defined, cannot compile watchdog applet
+#else
+# if defined WDIOC_SETOPTIONS && defined WDIOS_ENABLECARD
+       {
+               static const int enable = WDIOS_ENABLECARD;
+               ioctl_or_warn(3, WDIOC_SETOPTIONS, (void*) &enable);
+       }
+# endif
        ioctl_or_warn(3, WDIOC_SETTIMEOUT, &htimer_duration);
+#endif
+
 #if 0
        ioctl_or_warn(3, WDIOC_GETTIMEOUT, &htimer_duration);
-       printf("watchdog: SW timer is %dms, HW timer is %dms\n",
+       printf("watchdog: SW timer is %dms, HW timer is %ds\n",
                stimer_duration, htimer_duration * 1000);
 #endif
 
-       if (!(opts & OPT_FOREGROUND)) {
-               bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
-       }
+       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(stimer_duration * 1000L);