openwatchdog.c

简单的watchdog驱动,实现了定时重启

/*
 *此程序是用于测试watchdog驱动程序wdt3210.c
 *
 *实现的功能如下switch语句中:
 *                             1,喂狗
 *                             2,改timer时间，并喂狗
 *                             3,获得timer时间，并喂狗
 *                             4,关闭watchdog,并退出
 *
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <signal.h>

#include "watchdog.h"

#define SECONDS 100000000

int sleep_seconds(int seconds)
{

  while(seconds>0)
  {
    sleep(1);
    printf("\n%d seconds",seconds--);
  }

  return 0;
}



int main()
{

   int wdt_fd=-1;//设备文件描述符
   int selection;//用于switch语句中,选择case
   int sec;      //睡眠的时间
   int quit=0;   //判断是否关闭设备文件，退出循环
   int proId=-1; //fork Id,子进程和父进程的ID
   int sleepTime=20;//初始化的睡眠时间

   wdt_fd=open("/dev/watchdog",O_RDWR);

   if(wdt_fd < 0)
   {
     perror("watchdog");
   }
   else
   {
      printf("open watchdog successfully!\n");
      while(1)
      {
         proId=fork();//创建进程，从而分成子进程和父进程
         if(proId==0)
         {//子进程执行
           sleep_seconds(sleepTime);
           printf("\n===sleep=over==\n");
           break;
         }
         else
         {//父进程执行

         printf("\
                 \n1,adopt watchdog.\
                 \n2,change the time (input seconds). \
                 \n3,get the time (seconds).\
                 \nother numbers: close the watchdog.\
                ");
         scanf("%d",&selection);
         
         switch(selection) 
         {
            case 1 :
                    ioctl(wdt_fd,WDIOC_KEEPALIVE);// 喂狗
                    printf("\nadopt watchdog successfuly");

                    break;
            case 2 :
                    printf("\ninput the time:");
                    scanf("%d",&sec);
                    sleepTime=sec;
                    sec *= SECONDS;
                    ioctl(wdt_fd,WDIOC_SETTIMEOUT,&sec); //改timer时间
                    printf("\nset the timeout successfully");
                    
                    ioctl(wdt_fd,WDIOC_KEEPALIVE);//并喂狗
                    printf("\nadopt watchdog successfuly");
                    break;
            case 3 :
                    ioctl(wdt_fd,WDIOC_GETTIMEOUT,&sec);//获得timer时间
                    printf("\n=======<timer time=%d seconds>=======\n",sec/SECONDS);
                    printf("\nget the timeout successfully");
                    
                    ioctl(wdt_fd,WDIOC_KEEPALIVE);//并喂狗
                    printf("\nadopt watchdog successfuly");
                    break;
                   
            default :
                    ioctl(wdt_fd,WDIOS_DISABLECARD);//关闭watchdog
                    printf("\ndisable the watchdog and quit\n");
                    quit=1;//并退出
                    break;
         }
         
         if(quit)
           {//关闭设备文件，退出循环
             close(wdt_fd);
             break;
           }

         kill(proId,SIGSTOP);//由于将要再次创建一个进程或退出，所以杀死子进程
         }
      }
   }

    printf("\n====end=====\n");

    return 0;
}