Linux之看门狗

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <fcntl.h>#include <sys/ioctl.h>#include <errno.h>#include <sys/time.h>#include <unistd.h>#include <time.h>#include <getopt.h>#include <sys/signal.h>#include <termios.h>struct watchdog_info{    unsigned int options;   //options the card/driver supprots 19             unsigned int firmware_version;  //firmcard version of the card    unsigned char identity[32];     //identity of the board 21 };#define WATCHDOG_IOCTL_BASE 'W'#define WDIOC_GETSUPPORT _IOR(WATCHDOG_IOCTL_BASE, 0, struct watchdog_info)#define WDIOC_SETTIMEOUT _IOWR(WATCHDOG_IOCTL_BASE, 6, int)#define WDIOC_GETTIMEOUT _IOR(WATCHDOG_IOCTL_BASE, 7, int) 27 #define WDIOS_DISABLECARD 0x0001        /* Turn off the watchdog timer */#define WDIOS_ENABLECARD 0x0002 /* Turn on the watchdog timer */#define WDIOC_SETOPTIONS _IOR(WATCHDOG_IOCTL_BASE, 4, int)#define WDIOC_KEEPALIVE _IOR(WATCHDOG_IOCTL_BASE, 5, int)int Getch (void)   //无回显的从屏幕输入字符，来达到喂狗的目的{     int ch;     struct termios oldt, newt;   //终端设备结构体     tcgetattr(STDIN_FILENO, &oldt);   //获得终端属性     newt = oldt;     newt.c_lflag &= ~(ECHO|ICANON);   //设置无回显属性     tcsetattr(STDIN_FILENO, TCSANOW, &newt);  //设置新的终端属性     ch = getchar();   //从键盘输入一个数据     tcsetattr(STDIN_FILENO, TCSANOW, &oldt);  //恢复终端设备初始设置     return ch;} //suspend some secondsint zsleep(int millisecond){     unsigned long usec;     usec=1000*millisecond;     usleep(usec); //睡眠usec秒}int Init(){      int fd;     //open device file     fd = open("/dev/watchdog",O_RDWR);   //打开看门狗设备      if(fd < 0)     {         printf("device open fail\n");         return -1;     }     return fd;}int main(int argc,char **argv){     int fd,ch;     int i,j;     char c;     struct watchdog_info wi;     fd=Init();  //打开终端看门狗设备     //读板卡信息，但不常用      ioctl(fd,WDIOC_GETSUPPORT,&wi);     printf("%d,%s\n",wi.options,wi.identity);     //读看门狗溢出时间，默认是5s     //重新设置时间为10s     i=5;     printf("%d\n",ioctl(fd,WDIOC_SETTIMEOUT,&i));     //读新的设置时间      printf("%d\n",ioctl(fd,WDIOC_GETTIMEOUT,&i));     printf("%d\n",i);      //看门狗开始和停止工作，打开和关闭设备具有同样的功能     //关闭      i=WDIOS_DISABLECARD;     printf("%d\n",ioctl(fd,WDIOC_SETOPTIONS,&i));     //打开      i=WDIOS_ENABLECARD;     printf("%d\n",ioctl(fd,WDIOC_SETOPTIONS,&i));     while(1)     {           zsleep(100);           if((c=Getch())!=27){                //输入如果不是ESC，就喂狗，否则不喂狗，到时间后系统重启                ioctl(fd,WDIOC_KEEPALIVE,NULL);                //write(fd,NULL,1);     //同样是喂狗           }     }    close(fd);   //关闭设备     return 0;}