watchdogd.c revision 128705 
1/*
2 * Copyright (c) 2003  Sean M. Kelly <smkelly@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27/*
28 * Software watchdog daemon.
29 */
30
31#include <sys/types.h>
32__FBSDID("$FreeBSD: head/usr.sbin/watchdogd/watchdogd.c 128705 2004-04-28 07:35:03Z smkelly $");
33
34#include <sys/rtprio.h>
35#include <sys/stat.h>
36#include <sys/time.h>
37#include <sys/watchdog.h>
38
39#include <err.h>
40#include <errno.h>
41#include <fcntl.h>
42#include <math.h>
43#include <paths.h>
44#include <signal.h>
45#include <stdio.h>
46#include <stdlib.h>
47#include <string.h>
48#include <sysexits.h>
49#include <unistd.h>
50
51static void	parseargs(int, char *[]);
52static void	sighandler(int);
53static void	watchdog_loop(void);
54static int	watchdog_init(void);
55static int	watchdog_onoff(int onoff);
56static int	watchdog_patpat(void);
57static void	usage(void);
58
59int debugging = 0;
60int end_program = 0;
61const char *pidfile = _PATH_VARRUN "watchdogd.pid";
62int reset_mib[3];
63size_t reset_miblen = 3;
64u_int timeout = WD_TO_16SEC;
65u_int passive = 0;
66int is_daemon = 0;
67int fd = -1;
68int nap = 1;
69char *test_cmd = NULL;
70
71/*
72 * Periodically pat the watchdog, preventing it from firing.
73 */
74int
75main(int argc, char *argv[])
76{
77	struct rtprio rtp;
78	FILE *fp;
79
80	if (getuid() != 0)
81		errx(EX_SOFTWARE, "not super user");
82
83	parseargs(argc, argv);
84
85	rtp.type = RTP_PRIO_REALTIME;
86	rtp.prio = 0;
87	if (rtprio(RTP_SET, 0, &rtp) == -1)
88		err(EX_OSERR, "rtprio");
89
90	if (watchdog_init() == -1)
91		errx(EX_SOFTWARE, "unable to initialize watchdog");
92
93	if (is_daemon) {
94		if (watchdog_onoff(1) == -1)
95			exit(EX_SOFTWARE);
96
97		if (debugging == 0 && daemon(0, 0) == -1) {
98			watchdog_onoff(0);
99			err(EX_OSERR, "daemon");
100		}
101
102		signal(SIGHUP, SIG_IGN);
103		signal(SIGINT, sighandler);
104		signal(SIGTERM, sighandler);
105
106		fp = fopen(pidfile, "w");
107		if (fp != NULL) {
108			fprintf(fp, "%d\n", getpid());
109			fclose(fp);
110		}
111
112		watchdog_loop();
113
114		/* exiting */
115		watchdog_onoff(0);
116		unlink(pidfile);
117		return (EX_OK);
118	} else {
119		if (passive)
120			timeout |= WD_PASSIVE;
121		else
122			timeout |= WD_ACTIVE;
123		if (watchdog_patpat() < 0)
124			err(EX_OSERR, "patting the dog");
125		return (EX_OK);
126	}
127}
128
129/*
130 * Catch signals and begin shutdown process.
131 */
132static void
133sighandler(int signum)
134{
135
136	if (signum == SIGINT || signum == SIGTERM)
137		end_program = 1;
138}
139
140/*
141 * Open the watchdog device.
142 */
143static int
144watchdog_init()
145{
146
147	fd = open("/dev/" _PATH_WATCHDOG, O_RDWR);
148	if (fd >= 0)
149		return (0);
150	warn("Could not open watchdog device");
151	return (-1);
152}
153
154/*
155 * Main program loop which is iterated every second.
156 */
157static void
158watchdog_loop(void)
159{
160	struct stat sb;
161	int failed;
162
163	while (end_program == 0) {
164		failed = 0;
165
166		if (test_cmd != NULL)
167			failed = system(test_cmd);
168		else
169			failed = stat("/etc", &sb);
170
171		if (failed == 0)
172			watchdog_patpat();
173		sleep(nap);
174	}
175}
176
177/*
178 * Reset the watchdog timer. This function must be called periodically
179 * to keep the watchdog from firing.
180 */
181int
182watchdog_patpat(void)
183{
184
185	return ioctl(fd, WDIOCPATPAT, &timeout);
186}
187
188/*
189 * Toggle the kernel's watchdog. This routine is used to enable and
190 * disable the watchdog.
191 */
192static int
193watchdog_onoff(int onoff)
194{
195
196	if (onoff)
197		timeout |= WD_ACTIVE;
198	else
199		timeout &= ~WD_ACTIVE;
200	return watchdog_patpat();
201}
202
203/*
204 * Tell user how to use the program.
205 */
206static void
207usage()
208{
209	if (is_daemon)
210		fprintf(stderr, "usage: watchdogd [-d] [-e cmd] [-I file]\n");
211	else
212		fprintf(stderr, "usage: watchdog [-d] [-t]\n");
213	exit(EX_USAGE);
214}
215
216/*
217 * Handle the few command line arguments supported.
218 */
219static void
220parseargs(int argc, char *argv[])
221{
222	int c;
223	char *p;
224	double a;
225
226	c = strlen(argv[0]);
227	if (argv[0][c - 1] == 'd')
228		is_daemon = 1;
229	while ((c = getopt(argc, argv,
230	    is_daemon ? "I:de:s:t:?" : "dt:?")) != -1) {
231		switch (c) {
232		case 'I':
233			pidfile = optarg;
234			break;
235		case 'd':
236			debugging = 1;
237			break;
238		case 'e':
239			test_cmd = strdup(optarg);
240			break;
241#ifdef notyet
242		case 'p':
243			passive = 1;
244			break;
245#endif
246		case 's':
247			p = NULL;
248			errno = 0;
249			nap = strtol(optarg, &p, 0);
250			if ((p != NULL && *p != '\0') || errno != 0)
251				errx(EX_USAGE, "-s argument is not a number");
252			break;
253		case 't':
254			p = NULL;
255			errno = 0;
256			a = strtod(optarg, &p);
257			if ((p != NULL && *p != '\0') || errno != 0)
258				errx(EX_USAGE, "-t argument is not a number");
259			if (a < 0)
260				errx(EX_USAGE, "-t argument must be positive");
261			if (a == 0)
262				timeout = WD_TO_NEVER;
263			else
264				timeout = 1.0 + log(a * 1e9) / log(2.0);
265			if (debugging)
266				printf("Timeout is 2^%d nanoseconds\n",
267				    timeout);
268			break;
269		case '?':
270		default:
271			usage();
272			/* NOTREACHED */
273		}
274	}
275	if (is_daemon && timeout < WD_TO_1SEC)
276		errx(EX_USAGE, "-t argument is less than one second.");
277}
278