summaryrefslogtreecommitdiff
path: root/usr.sbin/watchdogd/watchdogd.c
blob: 02549b89fdf573390a384fb1c70ceb6984a130c4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
/*	$OpenBSD: watchdogd.c,v 1.11 2007/01/02 22:46:37 mbalmer Exp $ */

/*
 * Copyright (c) 2005 Marc Balmer <mbalmer@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/mman.h>

#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

volatile sig_atomic_t	quit = 0;

__dead void	usage(void);
void		sighdlr(int);
int		main(int, char *[]);

__dead void
usage(void)
{
	extern char *__progname;

	fprintf(stderr, "usage: %s [-dnq] [-i interval] [-p period]\n",
	    __progname);
	exit(1);
}

/* ARGSUSED */
void
sighdlr(int signum)
{
	quit = 1;
}

int
main(int argc, char *argv[])
{
	const char	*errstr;
	size_t		 len;
	u_int		 interval = 0, period = 30, nperiod;
	int		 ch, trigauto, sauto, speriod;
	int		 quiet = 0, daemonize = 1, retval = 1, do_restore = 1;
	int		 mib[3];

	while ((ch = getopt(argc, argv, "di:np:q")) != -1) {
		switch (ch) {
		case 'd':
			daemonize = 0;
			break;
		case 'i':
			interval = (u_int)strtonum(optarg, 1LL, 86400LL,
			    &errstr);
			if (errstr)
				errx(1, "interval is %s: %s", errstr, optarg);
			break;
		case 'n':
			do_restore = 0;
			break;
		case 'p':
			period = (u_int)strtonum(optarg, 2LL, 86400LL, &errstr);
			if (errstr)
				errx(1, "period is %s: %s", errstr, optarg);
			break;
		case 'q':
			quiet = 1;
			break;
		default:
			usage();
		}
	}

	if (interval == 0 && (interval = period / 3) == 0)
		interval = 1;

	if (period <= interval)
		errx(1, "retrigger interval too long");

	/* save kern.watchdog.period and kern.watchdog.auto for restore */
	mib[0] = CTL_KERN;
	mib[1] = KERN_WATCHDOG;
	mib[2] = KERN_WATCHDOG_PERIOD;

	len = sizeof(speriod);
	if (sysctl(mib, 3, &speriod, &len, &period, sizeof(period)) == -1) {
		if (errno == EOPNOTSUPP)
			errx(1, "no watchdog timer available");
		else
			err(1, "can't access kern.watchdog.period");
	}

	mib[2] = KERN_WATCHDOG_AUTO;
	len = sizeof(sauto);
	trigauto = 0;

	if (sysctl(mib, 3, &sauto, &len, &trigauto, sizeof(trigauto)) == -1)
		err(1, "can't access kern.watchdog.auto");

	/* Double check the timeout period, some devices change the value */
	mib[2] = KERN_WATCHDOG_PERIOD;
	len = sizeof(nperiod);
	if (sysctl(mib, 3, &nperiod, &len, NULL, 0) == -1) {
		warnx("can't read back kern.watchdog.period, "
		    "restoring original values");
		goto restore;
	}

	if (nperiod != period && !quiet)
		warnx("period adjusted to %d by device", nperiod);

	if (nperiod <= interval) {
		warnx("retrigger interval %d too long, "
		    "restoring original values", interval);
		goto restore;
	}

	if (daemonize && daemon(0, 0)) {
		warn("can't daemonize, restoring original values");
		goto restore;
	}

	(void)mlockall(MCL_CURRENT | MCL_FUTURE);
	setpriority(PRIO_PROCESS, getpid(), -5);

	signal(SIGTERM, sighdlr);

	retval = 0;
	while (!quit) {
		if (sysctl(mib, 3, NULL, 0, &period, sizeof(period)) == -1)
			quit = retval = 1;
		sleep(interval);
	}

	if (do_restore) {
restore:	sysctl(mib, 3, NULL, 0, &speriod, sizeof(speriod));
		mib[2] = KERN_WATCHDOG_AUTO;
		sysctl(mib, 3, NULL, 0, &sauto, sizeof(sauto));
	}

	return retval;
}