1 files changed, 25 insertions, 7 deletions

diff --git a/miscutils/watchdog.c b/miscutils/watchdog.c
index 07ae64e52..95e2f1a53 100644
--- a/miscutils/watchdog.c
+++ b/miscutils/watchdog.c
@@ -42,17 +42,36 @@
 #define OPT_STIMER      (1 << 1)
 #define OPT_HTIMER      (1 << 2)
 
-static void watchdog_shutdown(int sig UNUSED_PARAM)
+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");
-        write(3, &V, 1);  /* Magic, see watchdog-api.txt in kernel */
-        if (ENABLE_FEATURE_CLEAN_UP)
-                close(3);
+        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();
+
+        xmove_fd(xopen(device, O_WRONLY), 3);
+}
+
 int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int watchdog_main(int argc, char **argv)
 {
@@ -86,10 +105,9 @@ int watchdog_main(int argc, char **argv)
         if (opts & OPT_STIMER)
                 stimer_duration = xatou_sfx(st_arg, suffixes);
 
-        bb_signals(BB_FATAL_SIGS, watchdog_shutdown);
+        bb_signals(BB_FATAL_SIGS, shutdown_on_signal);
 
-        /* Use known fd # - avoid needing global 'int fd' */
-        xmove_fd(xopen(argv[argc - 1], O_WRONLY), 3);
+        watchdog_open(argv[argc - 1]);
 
         /* WDIOC_SETTIMEOUT takes seconds, not milliseconds */
         htimer_duration = htimer_duration / 1000;