c++每日八股文----socket多进程并发

  1 #include 
  2 #include 
  3 #include 
  4 #include 
  5 #include 
  6 #include 
  7 #include 
  8 #include 
  9 #include  
 10 #include 
 11 #include 
 12 
 13 #define SERV_PORT 9999
 14 
 15 
 16 
 17 //信号捕捉函数 回收子进程
 18 void catch_child(int signum)
 19 {
 20     while(waitpid(0, NULL, WNOHANG) > 0);
 21     return;
 22 }
 23 
 24 //scoket多进程并发
 25 int main()
 26 {
 27		int lfd, cfd;
 28     pid_t pid;
 29     char buf[BUFSIZ];
 30 
 31     struct sockaddr_in serv_addr, clit_addr;
 32 
 33     //初始化sockaddr结构体
 34     bzero(&serv_addr, sizeof(serv_addr));  //地址结构清零
 35     serv_addr.sin_family = AF_INET;
 36     serv_addr.sin_port = htons(SERV_PORT);
 37     serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
 38 
 39     socklen_t addr_len, clit_addr_len;
 40 
 41     lfd = socket(AF_INET, SOCK_STREAM, 0);
 42     if (lfd == -1){
 43         perror("socket error");
 44         exit(1);
 45     }
 46 
 47     addr_len = sizeof(serv_addr);
 48     int ret = bind(lfd, (const struct sockaddr *)&serv_addr, addr_len);
 49     if (ret == -1){
 50         perror("bind error");
 51         exit(1);
 52		}
 53 
 54     ret = listen(lfd, 128);
 55     if (ret == -1){
 56         perror("listen error");
 57         exit(1);
 58     }
 59 
 60     clit_addr_len = sizeof(clit_addr);
 61     int i;
 62     while(1){
 63         cfd = accept(lfd, (struct sockaddr *)&clit_addr, &clit_addr_len);
 64         if (cfd == -1){
 65             perror("accept error");
 66             exit(1);
 67         }
 68 
 69         //创建子进程
 70         pid = fork();
 71         if (pid < 0){
 72             perror("fork error");
 73             exit(1);
 74         } else if (pid == 0){ //子进程
 75             close(lfd);       //子进程负责连接客户端，所以关闭用于监听的文件描述符
 76			    for (; ;){        //不断循环，可以一直输入
 77                 ret = read(cfd, buf, sizeof(buf));
 78                 if (ret == -1){
 79                     perror("read error");
 80                     exit(1);
 81                 } else if (ret == 0){
 82                     close(cfd);
 83                     exit(1);
 84                 }
 85                 ret = write(STDOUT_FILENO, buf, ret);
 86                 if (ret == -1){
 87                     perror("write error");
 88                     exit(1);
 89                 }
 90                 for(i = 0; i < ret; i ++){
 91                     buf[i] = toupper(buf[i]);
 92                 }
 93                 write(cfd, buf, ret);
 94                 write(STDOUT_FILENO, buf, ret);
 95             }
 96         } else {             //父进程注册信号捕捉函数，不断回收子进程，防止僵尸进程的出现
 97             struct sigaction act;
 98             act.sa_handler = catch_child;
 99             sigemptyset(&act.sa_mask);
100             act.sa_flags = 0;
101             ret = sigaction(SIGCHLD, &act, NULL);
102             if (ret != 0){
103                 perror("sigaction error");
104                 exit(1);
105             }
106             close(cfd);      //父进程用于监听，所以关闭连接用的文件描述符
107             continue;
108         }
109     }
110 }