- Add a software watchdog facility.

This commit has two pieces. One half is the watchdog kernel code which lives
primarily in hardclock() in sys/kern/kern_clock.c. The other half is a userland
daemon which, when run, will keep the watchdog from firing while the userland
is intact and functioning.

Approved by:	jeff (mentor)

1 files changed, 232 insertions, 0 deletions

diff --git a/usr.sbin/watchdogd/watchdogd.c b/usr.sbin/watchdogd/watchdogd.c
new file mode 100644
index 0000000..3dd2f52
--- /dev/null
+++ b/usr.sbin/watchdogd/watchdogd.c
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2003  Sean M. Kelly <smkelly@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Software watchdog daemon.
+ */
+
+#include <sys/cdefs.h>                                                          
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/errno.h>
+#include <sys/sysctl.h>
+#include <sys/time.h>
+#include <sys/rtprio.h>
+#include <sys/stat.h>
+
+#include <err.h>
+#include <paths.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+#include <signal.h>
+
+static void	parseargs(int, char *[]);
+static void	sighandler(int);
+static void	watchdog_loop(void);
+static int	watchdog_init(void);
+static int	watchdog_onoff(int onoff);
+static int	watchdog_tickle(void);
+static void	usage(void);
+
+int debugging = 0;
+int end_program = 0;
+const char *pidfile = _PATH_VARRUN "watchdogd.pid";
+int reset_mib[3];
+int reset_miblen = 3;
+
+/*
+ * Periodically write to the debug.watchdog.reset sysctl OID
+ * to keep the software watchdog from firing.
+ */
+int
+main(int argc, char *argv[])
+{
+	struct rtprio rtp;
+	FILE *fp;
+
+	if (getuid() != 0)
+		errx(EX_SOFTWARE, "not super user");
+		
+	parseargs(argc, argv);
+
+	rtp.type = RTP_PRIO_REALTIME;
+	rtp.prio = 0;
+	if (rtprio(RTP_SET, 0, &rtp) == -1)
+		err(EX_OSERR, "rtprio");
+
+	if (watchdog_init() == -1)
+		exit(EX_SOFTWARE);
+
+	if (watchdog_onoff(1) == -1)
+		exit(EX_SOFTWARE);
+
+	if (debugging == 0 && daemon(0, 0) == -1) {
+		watchdog_onoff(0);
+		err(EX_OSERR, "daemon");
+	}
+
+	signal(SIGHUP, SIG_IGN);
+	signal(SIGINT, sighandler);
+	signal(SIGTERM, sighandler);
+
+	fp = fopen(pidfile, "w");
+	if (fp != NULL) {
+		fprintf(fp, "%d\n", getpid());
+		fclose(fp);
+	}
+
+	watchdog_loop();
+
+	/* exiting */
+	watchdog_onoff(0);
+	unlink(pidfile);
+	return (EX_OK);
+}
+
+/*
+ * Catch signals and begin shutdown process.
+ */
+static void
+sighandler(int signum)
+{
+
+	if (signum == SIGINT || signum == SIGTERM)
+		end_program = 1;
+}
+
+/*
+ * Locate the OID for the 'debug.watchdog.reset' sysctl setting.
+ * Upon finding it, do an initial reset on the watchdog.
+ */
+static int
+watchdog_init()
+{
+	int error;
+
+	error = sysctlnametomib("debug.watchdog.reset", reset_mib, 
+		&reset_miblen);
+	if (error == -1) {
+		fprintf(stderr, "Could not find reset OID: %s\n",
+			strerror(errno));
+		return (error);
+	}
+	return watchdog_tickle();
+}
+
+/*
+ * Main program loop which is iterated every second.
+ */
+static void
+watchdog_loop(void)
+{
+	struct stat sb;
+	int failed;
+
+	while (end_program == 0) {
+		failed = 0;
+
+		failed = stat("/etc", &sb);
+
+		if (failed == 0)
+			watchdog_tickle();
+		sleep(1);
+	}
+}
+
+/*
+ * Reset the watchdog timer. This function must be called periodically
+ * to keep the watchdog from firing.
+ */
+int
+watchdog_tickle(void)
+{
+
+	return sysctl(reset_mib, reset_miblen, NULL, NULL, NULL, 0);
+}
+
+/*
+ * Toggle the kernel's watchdog. This routine is used to enable and
+ * disable the watchdog.
+ */
+static int
+watchdog_onoff(int onoff)
+{
+	int mib[3]
+	int error
+	int len;
+
+	len = 3;
+
+	error = sysctlnametomib("debug.watchdog.enabled", mib, &len);
+	if (error == 0)
+		error = sysctl(mib, len, NULL, NULL, &onoff, sizeof(onoff));
+
+	if (error == -1) {
+		fprintf(stderr, "Could not %s watchdog: %s\n",
+			(onoff > 0) ? "enable" : "disable",
+			strerror(errno));
+		return (error);
+	}
+	return (0);
+}
+
+/*
+ * Tell user how to use the program.
+ */
+static void
+usage()
+{
+	fprintf(stderr, "usage: watchdogd [-d] [-I file]\n");
+	exit(EX_USAGE);
+}
+
+/*
+ * Handle the few command line arguments supported.
+ */
+static void
+parseargs(int argc, char *argv[])
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "I:d?")) != -1) {
+		switch (c) {
+		case 'I':
+			pidfile = optarg;
+			break;
+		case 'd':
+			debugging = 1;
+			break;
+		case '?':
+		default:
+			usage();
+			/* NOTREACHED */
+		}
+	}
+}