1 /* $OpenBSD: sthen $ */
2
3 /*
4 * Copyright (c) 2005 Marc Balmer <mbalmer@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <sys/param.h>
20 #include <sys/ioctl.h>
21 #include <sys/mman.h>
22 #include <sys/resource.h>
23 #include <sys/sysctl.h>
24 #include <sys/time.h>
25 #include <sys/types.h>
26 #include <sys/wdog.h>
27
28 #include <err.h>
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <unistd.h>
34
35 static volatile sig_atomic_t quit = 0;
36
37 static void usage(void) __dead2;
38 static void sighdlr(int);
39
40 static void
usage(void)41 usage(void)
42 {
43 fprintf(stderr, "usage: %s [-dnq] [-i interval] [-p period]\n",
44 getprogname());
45 exit(1);
46 }
47
48 /* ARGSUSED */
49 static void
sighdlr(__unused int signum)50 sighdlr(__unused int signum)
51 {
52 quit = 1;
53 }
54
55 int
main(int argc,char * argv[])56 main(int argc, char *argv[])
57 {
58 struct rlimit rlim;
59 const char *errstr;
60 size_t len;
61 u_int interval = 0, period = 30, nperiod;
62 int fd, ch, trigauto, sauto, speriod;
63 int quiet = 0, daemonize = 1, retval = 1, do_restore = 1;
64
65 while ((ch = getopt(argc, argv, "di:np:q")) != -1) {
66 switch (ch) {
67 case 'd':
68 daemonize = 0;
69 break;
70 case 'i':
71 interval = (u_int)strtonum(optarg, 1LL, 86400LL,
72 &errstr);
73 if (errstr)
74 errx(1, "interval is %s: %s", errstr, optarg);
75 break;
76 case 'n':
77 do_restore = 0;
78 break;
79 case 'p':
80 period = (u_int)strtonum(optarg, 2LL, 86400LL, &errstr);
81 if (errstr)
82 errx(1, "period is %s: %s", errstr, optarg);
83 break;
84 case 'q':
85 quiet = 1;
86 break;
87 default:
88 usage();
89 }
90 }
91
92 argc -= optind;
93 argv += optind;
94 if (argc > 0)
95 usage();
96
97 if (interval == 0 && (interval = period / 3) == 0)
98 interval = 1;
99
100 if (period <= interval)
101 errx(1, "retrigger interval too long");
102
103 /* save kern.watchdog.period and kern.watchdog.auto for restore */
104
105 len = sizeof(speriod);
106 if (sysctlbyname("kern.watchdog.period", &speriod, &len, &period, sizeof(period)) == -1) {
107 if (errno == EOPNOTSUPP)
108 errx(1, "no watchdog timer available");
109 else
110 err(1, "can't access kern.watchdog.period");
111 }
112
113 len = sizeof(sauto);
114 trigauto = 0;
115
116 if (sysctlbyname("kern.watchdog.auto", &sauto, &len, &trigauto, sizeof(trigauto)) == -1)
117 err(1, "can't access kern.watchdog.auto");
118
119 /* Double check the timeout period, some devices change the value */
120 len = sizeof(nperiod);
121 if (sysctlbyname("kern.watchdog.period", &nperiod, &len, NULL, 0) == -1) {
122 warnx("can't read back kern.watchdog.period, "
123 "restoring original values");
124 goto restore;
125 }
126
127 if (nperiod != period && !quiet)
128 warnx("period adjusted to %d by device", nperiod);
129
130 if (nperiod <= interval) {
131 warnx("retrigger interval %d too long, "
132 "restoring original values", interval);
133 goto restore;
134 }
135
136 if ((fd = open("/dev/wdog", O_RDWR)) == -1) {
137 err(1, "can't open /dev/wdog");
138 }
139
140 if (daemonize && daemon(0, 0)) {
141 warn("can't daemonize, restoring original values");
142 goto restore;
143 }
144
145 /*
146 * mlockall() below will wire the whole stack up to the limit
147 * thus we have to reduce stack size to avoid resource abuse
148 */
149 rlim.rlim_cur = 256 * 1024;
150 rlim.rlim_max = 256 * 1024;
151 (void)setrlimit(RLIMIT_STACK, &rlim);
152
153 setpriority(PRIO_PROCESS, getpid(), -5);
154
155 signal(SIGTERM, sighdlr);
156
157 retval = 0;
158 while (!quit) {
159 if (ioctl(fd, WDIOCRESET, &period, sizeof(period)) == -1)
160 quit = retval = 1;
161 sleep(interval);
162 }
163
164 close(fd);
165
166 if (do_restore) {
167 restore: sysctlbyname("kern.watchdog.period", NULL, 0, &speriod, sizeof(speriod));
168 sysctlbyname("kern.watchdog.auto", NULL, 0, &sauto, sizeof(sauto));
169 }
170 return retval;
171 }
172