守护进程（管道通信实现）

创建两个进程，一个有名管道。一个进程如果正在运行就往管道里面发送运行信息，守护进程负责读取运行信息，一旦守护进程超过三秒读取不到运行信息，就自动将进程重启

守护进程代码：

 #include

 #include

 #include

 #include

 #include

 #include

 #include

 #define FIFO "/root/linux/myfifo"


 main(int argc, char** argv)

 {

     char buf[100];

     int fd;

     int nread;

     int count = 0;


     if((mkfifo(FIFO,O_CREAT|O_EXCL) < 0) &&(errno != EEXIST))

    {

         printf("creat fifo error!\n");

     }


     printf("perparing for reading bytes...\n");


     memset(buf,0,sizeof(buf));



     fd = open(FIFO,O_RDONLY|O_NONBLOCK,0);

     if(fd == -1)

     {

         perror("open");

         exit(1);

     }

     while(1)

    {

         memset(buf,0,sizeof(buf));


         if(nread = read(fd,buf,100) <= 0)

        {


              if(errno == EAGAIN)

             {

                   printf("no data yet\n");

              }

              count++;

              printf("read none\n");

              sleep(1);

              if(count == 3)

             {

                  printf("重新启动函数\n");

                  system("./write success");

                  count = 0;

             }

         }

         else

        {

              printf("read %s from FIFO\n",buf);

              sleep(1);

         }

    }

    pause();

    unlink(FIFO);

 }

守护进程代码：

 #include

 #include

 #include

 #include

 #include

 #include

 #include

 #define FIFO_SERVER "/root/linux/myfifo"


 main(int argc, char** argv)

 {

     int fd;

     char buf[100];

     int nwrite;


     fd = open(FIFO_SERVER,O_WRONLY|O_NONBLOCK,0);

     if(argc == 1)

     {

         printf("please send st\n");

     exit(-1);

     }


     strcpy(buf,argv[1]);


     if((nwrite = write(fd,buf,100)) == 1)

     {

         if(errno == EAGAIN)

        {

             printf("not been read yet\n");

        }

        else

       {

             printf("write %s to FIFO\n",buf);

        }

     }

 }