utilities/ovs-wdt.c

   1 /* Copyright (c) 2008, 2009 Nicira Networks, Inc.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <unistd.h>
  20 #include <fcntl.h>
  21 #include <errno.h>
  22 #include <getopt.h>
  23 #include <signal.h>
  24 #include <sys/ioctl.h>
  25 #include <linux/types.h>
  26 #include <linux/watchdog.h>
  27
  28
  29 /* Default values for the interval and timer.  In seconds. */
  30 #define DEFAULT_INTERVAL  1
  31 #define DEFAULT_TIMEOUT   30
  32
  33 int fd = -1;
  34
  35 /* The WDT is automatically enabled when /dev/watchdog is opened.  If we
  36  * do not send the magic value to the device first before exiting, the
  37  * system will reboot.  This function allows the program to exit without
  38  * causing a reboot.
  39  */
  40 static void
  41 cleanup(void)
  42 {
  43     if (fd == -1) {
  44         return;
  45     }
  46
  47     /* Writing the magic value "V" to the device is an indication that
  48      * the device is about to be closed.  This causes the watchdog to be
  49      * disabled after the call to close.
  50      */
  51     if (write(fd, "V", 1) != 1) {
  52         fprintf(stderr, "Couldn't write magic val: %d\n", errno);
  53         return;
  54     }
  55     close(fd);
  56     fd = -1;
  57 }
  58
  59
  60 /* If we receive a SIGINT, cleanup first, which will disable the
  61  * watchdog timer.
  62  */
  63 static void
  64 sighandler(int signum)
  65 {
  66     cleanup();
  67     signal(signum, SIG_DFL);
  68     raise(signum);
  69 }
  70
  71 static void
  72 setup_signal(void)
  73 {
  74     struct sigaction action;
  75
  76     action.sa_handler = sighandler;
  77     sigemptyset(&action.sa_mask);
  78     action.sa_flags = 0;
  79
  80     if (sigaction(SIGINT, &action, NULL) != 0) {
  81         fprintf(stderr, "Problem setting up SIGINT handler...\n");
  82     }
  83     if (sigaction(SIGTERM, &action, NULL) != 0) {
  84         fprintf(stderr, "Problem setting up SIGTERM handler...\n");
  85     }
  86 }
  87
  88
  89 /* Print information on the WDT hardware */
  90 static void
  91 print_wdt_info(void)
  92 {
  93     struct watchdog_info ident;
  94
  95     if (ioctl(fd, WDIOC_GETSUPPORT, &ident) == -1) {
  96         fprintf(stderr, "Couldn't get version: %d\n", errno);
  97         cleanup();
  98         exit(-1);
  99     }
 100     printf("identity: %s, ver: %d, opt: %#x\n", ident.identity,
 101             ident.firmware_version, ident.options);
 102 }
 103
 104
 105 static void
 106 print_help(char *progname)
 107 {
 108     printf("%s: Watchdog timer utility\n", progname);
 109     printf("usage: %s [OPTIONS]\n\n", progname);
 110     printf("Options:\n");
 111     printf("  -t, --timeout=SECS     expiration time of WDT (default: %d)\n",
 112             DEFAULT_TIMEOUT);
 113     printf("  -i, --interval=SECS    interval to send keep-alives (default: %d)\n",
 114             DEFAULT_INTERVAL);
 115     printf("  -d, --disable          disable the WDT and exit\n");
 116     printf("  -h, --help             display this help message\n");
 117     printf("  -v, --verbose          enable verbose printing\n");
 118     printf("  -V, --version          display version information of WDT and exit\n");
 119 }
 120
 121
 122 int main(int argc, char *argv[])
 123 {
 124     int arg;
 125     int optc;
 126     int verbose = 0;
 127     int interval = DEFAULT_INTERVAL;
 128     int timeout = DEFAULT_TIMEOUT;
 129     static struct option const longopts[] =
 130     {
 131         {"timeout", required_argument, NULL, 't'},
 132         {"interval", required_argument, NULL, 'i'},
 133         {"disable", no_argument, NULL, 'd'},
 134         {"help", no_argument, NULL, 'h'},
 135         {"verbose", no_argument, NULL, 'v'},
 136         {"version", no_argument, NULL, 'V'},
 137         {0, 0, 0, 0}
 138     };
 139
 140     setup_signal();
 141
 142     fd = open("/dev/watchdog", O_RDWR);
 143     if (fd == -1) {
 144         fprintf(stderr, "Couldn't open watchdog device: %s\n", strerror(errno));
 145         exit(-1);
 146     }
 147
 148     while ((optc = getopt_long(argc, argv, "t:i:dh?vV", longopts, NULL)) != -1) {
 149         switch (optc) {
 150         case 't':
 151             timeout = strtol(optarg, NULL, 10);
 152             if (!timeout) {
 153                 fprintf(stderr, "Invalid timeout: %s\n", optarg);
 154                 goto error;
 155             }
 156             break;
 157
 158        case 'i':
 159             interval = strtol(optarg, NULL, 10);
 160             if (!interval) {
 161                 fprintf(stderr, "Invalid interval: %s\n", optarg);
 162                 goto error;
 163             }
 164             break;
 165
 166         case 'd':
 167             arg = WDIOS_DISABLECARD;
 168             if (ioctl(fd, WDIOC_SETOPTIONS, &arg) == -1) {
 169                 fprintf(stderr, "Couldn't disable: %d\n", errno);
 170                 goto error;
 171             }
 172             cleanup();
 173             exit(0);
 174             break;
 175
 176         case 'h':
 177             print_help(argv[0]);
 178             cleanup();
 179             exit(0);
 180             break;
 181
 182         case 'v':
 183             verbose = 1;
 184             break;
 185
 186         case 'V':
 187             print_wdt_info();
 188             cleanup();
 189             exit(0);
 190             break;
 191
 192         default:
 193             print_help(argv[0]);
 194             goto error;
 195             break;
 196         }
 197     }
 198
 199     argc -= optind;
 200     argv += optind;
 201
 202     /* Sanity-check the arguments */
 203     if (argc != 0) {
 204         fprintf(stderr, "Illegal argument: %s\n", argv[0]);
 205         goto error;
 206     }
 207
 208     if (verbose) {
 209         print_wdt_info();
 210         printf("timeout: %d, interval: %d\n", timeout, interval);
 211     }
 212
 213     /* Prevent the interval being greater than the timeout, since it
 214      * will always cause a reboot.
 215      */
 216     if (interval > timeout) {
 217         fprintf(stderr, "Interval greater than timeout: %d > %d\n",
 218                 interval, timeout);
 219         goto error;
 220     }
 221
 222     /* Always set the timeout */
 223     if (ioctl(fd, WDIOC_SETTIMEOUT, &timeout) == -1) {
 224         fprintf(stderr, "Couldn't set timeout: %d\n", errno);
 225         goto error;
 226     }
 227
 228     /* Loop and send a keep-alive every "interval" seconds */
 229     while (1) {
 230         if (verbose) {
 231             if (ioctl(fd, WDIOC_GETTIMELEFT, &arg) == -1) {
 232                 fprintf(stderr, "Couldn't get time left: %d\n", errno);
 233                 goto error;
 234             }
 235             printf("Sending keep alive, time remaining: %d\n", arg);
 236         }
 237
 238         /* Send a keep-alive.  The argument is ignored */
 239         if (ioctl(fd, WDIOC_KEEPALIVE, &arg) == -1) {
 240             fprintf(stderr, "Couldn't keepalive: %d\n", errno);
 241             goto error;
 242         }
 243
 244         sleep(interval);
 245     }
 246
 247     /* Never directly reached... */
 248 error:
 249     cleanup();
 250     exit(-1);
 251 }