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("$FreeBSD$"); 33 34 #include <sys/rtprio.h> 35 #include <sys/stat.h> 36 #include <sys/sysctl.h> 37 #include <sys/time.h> 38 #include <sys/watchdog.h> 39 40 #include <err.h> 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <math.h> 44 #include <paths.h> 45 #include <signal.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <sysexits.h> 50 #include <unistd.h> 51 52 static void parseargs(int, char *[]); 53 static void sighandler(int); 54 static void watchdog_loop(void); 55 static int watchdog_init(void); 56 static int watchdog_onoff(int onoff); 57 static int watchdog_patpat(void); 58 static void usage(void); 59 60 int debugging = 0; 61 int end_program = 0; 62 const char *pidfile = _PATH_VARRUN "watchdogd.pid"; 63 int reset_mib[3]; 64 size_t reset_miblen = 3; 65 u_int timeout = WD_TO_16SEC; 66 u_int passive = 0; 67 int is_daemon = 0; 68 int fd = -1; 69 int nap = 1; 70 char *test_cmd = NULL; 71 72 /* 73 * Periodically write to the debug.watchdog.reset sysctl OID 74 * to keep the software watchdog from firing. 75 */ 76 int 77 main(int argc, char *argv[]) 78 { 79 struct rtprio rtp; 80 FILE *fp; 81 82 if (getuid() != 0) 83 errx(EX_SOFTWARE, "not super user"); 84 85 parseargs(argc, argv); 86 87 rtp.type = RTP_PRIO_REALTIME; 88 rtp.prio = 0; 89 if (rtprio(RTP_SET, 0, &rtp) == -1) 90 err(EX_OSERR, "rtprio"); 91 92 if (watchdog_init() == -1) 93 errx(EX_SOFTWARE, "unable to initialize watchdog"); 94 95 if (is_daemon) { 96 if (watchdog_onoff(1) == -1) 97 exit(EX_SOFTWARE); 98 99 if (debugging == 0 && daemon(0, 0) == -1) { 100 watchdog_onoff(0); 101 err(EX_OSERR, "daemon"); 102 } 103 104 signal(SIGHUP, SIG_IGN); 105 signal(SIGINT, sighandler); 106 signal(SIGTERM, sighandler); 107 108 fp = fopen(pidfile, "w"); 109 if (fp != NULL) { 110 fprintf(fp, "%d\n", getpid()); 111 fclose(fp); 112 } 113 114 watchdog_loop(); 115 116 /* exiting */ 117 watchdog_onoff(0); 118 unlink(pidfile); 119 return (EX_OK); 120 } else { 121 if (passive) 122 timeout |= WD_PASSIVE; 123 else 124 timeout |= WD_ACTIVE; 125 if (watchdog_patpat() < 0) 126 err(EX_OSERR, "patting the dog"); 127 return (EX_OK); 128 } 129 } 130 131 /* 132 * Catch signals and begin shutdown process. 133 */ 134 static void 135 sighandler(int signum) 136 { 137 138 if (signum == SIGINT || signum == SIGTERM) 139 end_program = 1; 140 } 141 142 /* 143 * Locate the OID for the 'debug.watchdog.reset' sysctl setting. 144 * Upon finding it, do an initial reset on the watchdog. 145 */ 146 static int 147 watchdog_init() 148 { 149 150 fd = open("/dev/" _PATH_WATCHDOG, O_RDWR); 151 if (fd >= 0) 152 return (0); 153 warn("Could not open watchdog device"); 154 return (-1); 155 } 156 157 /* 158 * Main program loop which is iterated every second. 159 */ 160 static void 161 watchdog_loop(void) 162 { 163 struct stat sb; 164 int failed; 165 166 while (end_program == 0) { 167 failed = 0; 168 169 if (test_cmd != NULL) 170 failed = system(test_cmd); 171 else 172 failed = stat("/etc", &sb); 173 174 if (failed == 0) 175 watchdog_patpat(); 176 sleep(nap); 177 } 178 } 179 180 /* 181 * Reset the watchdog timer. This function must be called periodically 182 * to keep the watchdog from firing. 183 */ 184 int 185 watchdog_patpat(void) 186 { 187 188 return ioctl(fd, WDIOCPATPAT, &timeout); 189 } 190 191 /* 192 * Toggle the kernel's watchdog. This routine is used to enable and 193 * disable the watchdog. 194 */ 195 static int 196 watchdog_onoff(int onoff) 197 { 198 199 if (onoff) 200 timeout |= WD_ACTIVE; 201 else 202 timeout &= ~WD_ACTIVE; 203 return watchdog_patpat(); 204 } 205 206 /* 207 * Tell user how to use the program. 208 */ 209 static void 210 usage() 211 { 212 if (is_daemon) 213 fprintf(stderr, "usage: watchdogd [-d] [-e cmd] [-I file]\n"); 214 else 215 fprintf(stderr, "usage: watchdog [-d] [-t]\n"); 216 exit(EX_USAGE); 217 } 218 219 /* 220 * Handle the few command line arguments supported. 221 */ 222 static void 223 parseargs(int argc, char *argv[]) 224 { 225 int c; 226 char *p; 227 double a; 228 229 c = strlen(argv[0]); 230 if (argv[0][c - 1] == 'd') 231 is_daemon = 1; 232 while ((c = getopt(argc, argv, 233 is_daemon ? "I:de:s:t:?" : "dt:?")) != -1) { 234 switch (c) { 235 case 'I': 236 pidfile = optarg; 237 break; 238 case 'd': 239 debugging = 1; 240 break; 241 case 'e': 242 test_cmd = strdup(optarg); 243 break; 244 #ifdef notyet 245 case 'p': 246 passive = 1; 247 break; 248 #endif 249 case 's': 250 p = NULL; 251 errno = 0; 252 nap = strtol(optarg, &p, 0); 253 if ((p != NULL && *p != '\0') || errno != 0) 254 errx(EX_USAGE, "-s argument is not a number"); 255 break; 256 case 't': 257 p = NULL; 258 errno = 0; 259 a = strtod(optarg, &p); 260 if ((p != NULL && *p != '\0') || errno != 0) 261 errx(EX_USAGE, "-t argument is not a number"); 262 if (a < 0) 263 errx(EX_USAGE, "-t argument must be positive"); 264 if (a == 0) 265 timeout = WD_TO_NEVER; 266 else 267 timeout = 1.0 + log(a * 1e9) / log(2.0); 268 if (debugging) 269 printf("Timeout is 2^%d nanoseconds\n", 270 timeout); 271 break; 272 case '?': 273 default: 274 usage(); 275 /* NOTREACHED */ 276 } 277 } 278 if (is_daemon && timeout < WD_TO_1SEC) 279 errx(EX_USAGE, "-t argument is less than one second."); 280 } 281