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/* Copyright (c) 2008, 2009 Nicira Networks, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <getopt.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/watchdog.h>
/* Default values for the interval and timer. In seconds. */
#define DEFAULT_INTERVAL 1
#define DEFAULT_TIMEOUT 30
int fd = -1;
/* The WDT is automatically enabled when /dev/watchdog is opened. If we
* do not send the magic value to the device first before exiting, the
* system will reboot. This function allows the program to exit without
* causing a reboot.
*/
static void
cleanup(void)
{
if (fd == -1) {
return;
}
/* Writing the magic value "V" to the device is an indication that
* the device is about to be closed. This causes the watchdog to be
* disabled after the call to close.
*/
if (write(fd, "V", 1) != 1) {
fprintf(stderr, "Couldn't write magic val: %d\n", errno);
return;
}
close(fd);
fd = -1;
}
/* If we receive a SIGINT, cleanup first, which will disable the
* watchdog timer.
*/
static void
sighandler(int signum)
{
cleanup();
signal(signum, SIG_DFL);
raise(signum);
}
static void
setup_signal(void)
{
struct sigaction action;
action.sa_handler = sighandler;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
if (sigaction(SIGINT, &action, NULL) != 0) {
fprintf(stderr, "Problem setting up SIGINT handler...\n");
}
if (sigaction(SIGTERM, &action, NULL) != 0) {
fprintf(stderr, "Problem setting up SIGTERM handler...\n");
}
}
/* Print information on the WDT hardware */
static void
print_wdt_info(void)
{
struct watchdog_info ident;
if (ioctl(fd, WDIOC_GETSUPPORT, &ident) == -1) {
fprintf(stderr, "Couldn't get version: %d\n", errno);
cleanup();
exit(-1);
}
printf("identity: %s, ver: %d, opt: %#x\n", ident.identity,
ident.firmware_version, ident.options);
}
static void
print_help(char *progname)
{
printf("%s: Watchdog timer utility\n", progname);
printf("usage: %s [OPTIONS]\n\n", progname);
printf("Options:\n");
printf(" -t, --timeout=SECS expiration time of WDT (default: %d)\n",
DEFAULT_TIMEOUT);
printf(" -i, --interval=SECS interval to send keep-alives (default: %d)\n",
DEFAULT_INTERVAL);
printf(" -d, --disable disable the WDT and exit\n");
printf(" -h, --help display this help message\n");
printf(" -v, --verbose enable verbose printing\n");
printf(" -V, --version display version information of WDT and exit\n");
}
int main(int argc, char *argv[])
{
int arg;
int optc;
int verbose = 0;
int interval = DEFAULT_INTERVAL;
int timeout = DEFAULT_TIMEOUT;
static struct option const longopts[] =
{
{"timeout", required_argument, NULL, 't'},
{"interval", required_argument, NULL, 'i'},
{"disable", no_argument, NULL, 'd'},
{"help", no_argument, NULL, 'h'},
{"verbose", no_argument, NULL, 'v'},
{"version", no_argument, NULL, 'V'},
{0, 0, 0, 0}
};
setup_signal();
fd = open("/dev/watchdog", O_RDWR);
if (fd == -1) {
fprintf(stderr, "Couldn't open watchdog device: %s\n", strerror(errno));
exit(-1);
}
while ((optc = getopt_long(argc, argv, "t:i:dh?vV", longopts, NULL)) != -1) {
switch (optc) {
case 't':
timeout = strtol(optarg, NULL, 10);
if (!timeout) {
fprintf(stderr, "Invalid timeout: %s\n", optarg);
goto error;
}
break;
case 'i':
interval = strtol(optarg, NULL, 10);
if (!interval) {
fprintf(stderr, "Invalid interval: %s\n", optarg);
goto error;
}
break;
case 'd':
arg = WDIOS_DISABLECARD;
if (ioctl(fd, WDIOC_SETOPTIONS, &arg) == -1) {
fprintf(stderr, "Couldn't disable: %d\n", errno);
goto error;
}
cleanup();
exit(0);
break;
case 'h':
print_help(argv[0]);
cleanup();
exit(0);
break;
case 'v':
verbose = 1;
break;
case 'V':
print_wdt_info();
cleanup();
exit(0);
break;
default:
print_help(argv[0]);
goto error;
break;
}
}
argc -= optind;
argv += optind;
/* Sanity-check the arguments */
if (argc != 0) {
fprintf(stderr, "Illegal argument: %s\n", argv[0]);
goto error;
}
if (verbose) {
print_wdt_info();
printf("timeout: %d, interval: %d\n", timeout, interval);
}
/* Prevent the interval being greater than the timeout, since it
* will always cause a reboot.
*/
if (interval > timeout) {
fprintf(stderr, "Interval greater than timeout: %d > %d\n",
interval, timeout);
goto error;
}
/* Always set the timeout */
if (ioctl(fd, WDIOC_SETTIMEOUT, &timeout) == -1) {
fprintf(stderr, "Couldn't set timeout: %d\n", errno);
goto error;
}
/* Loop and send a keep-alive every "interval" seconds */
while (1) {
if (verbose) {
if (ioctl(fd, WDIOC_GETTIMELEFT, &arg) == -1) {
fprintf(stderr, "Couldn't get time left: %d\n", errno);
goto error;
}
printf("Sending keep alive, time remaining: %d\n", arg);
}
/* Send a keep-alive. The argument is ignored */
if (ioctl(fd, WDIOC_KEEPALIVE, &arg) == -1) {
fprintf(stderr, "Couldn't keepalive: %d\n", errno);
goto error;
}
sleep(interval);
}
/* Never directly reached... */
error:
cleanup();
exit(-1);
}
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