扩展知识点----Linux中看门狗应用编程

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#define WDOG_DEV  “/dev/watchdog”
int main(int argc,char *argv[])
{
struct watchdog_info info;
int timeout; int time;
int fd;
int op;
/* 打开看门狗 */
fd = open(WDOG_DEV, O_RDWR);
if (0 > fd) { fprintf(stderr, "open error: %s: %s\n", WDOG_DEV, strerror(errno)); exit(EXIT_FAILURE); }
/* 打开之后看门狗计时器会开启、先停止它 */
op = WDIOS_DISABLECARD;
if (0 > ioctl(fd, WDIOC_SETOPTIONS, &op)) {
fprintf(stderr, "ioctl error: WDIOC_SETOPTIONS: %s\n", strerror(errno));
close(fd);
exit(EXIT_FAILURE);
}
timeout = atoi(argv[1]);
if (1 > timeout)
timeout = 1;
/* 设置超时时间 */
printf("timeout: %ds\n", timeout);
if (0 > ioctl(fd, WDIOC_SETTIMEOUT, &timeout)) {
fprintf(stderr, "ioctl error: WDIOC_SETTIMEOUT: %s\n", strerror(errno));
close(fd);
exit(EXIT_FAILURE);
}
/* 开启看门狗计时器 */
op = WDIOS_ENABLECARD;
if (0 > ioctl(fd, WDIOC_SETOPTIONS, &op)) {
fprintf(stderr, "ioctl error: WDIOC_SETOPTIONS: %s\n", strerror(errno));
close(fd); exit(EXIT_FAILURE);
}
/* 喂狗 */
time = (timeout * 1000 - 100) * 1000;//喂狗时间设置 us 微秒、在超时时间到来前 100ms 喂狗
for ( ; ; ) {
usleep(time);
ioctl(fd, WDIOC_KEEPALIVE, NULL);
}
}