1. #include <pthread.h>
    2. #include <signal.h>
    3. #include "hl.h"
    5. void cli_data_handle (void *arg);
    7. void sig_child_handle(int signo)
    8. {
    9.     if(SIGCHLD == signo) {
    10.         waitpid(-1, NULL,  WNOHANG);
    11.     }
    12. }
    13. int main (void)
    14. {
    16.     int fd = -1;
    17.     struct sockaddr_in sin;
    19.     signal(SIGCHLD, sig_child_handle);    
    21.     /* 1. 创建socket fd */
    22.     if ((fd = socket (AF_INET, SOCK_STREAM, 0)) < 0) {
    23.         perror ("socket");
    24.         exit (1);
    25.     }
    27.     /*优化4： 允许绑定地址快速重用 */
    28.     int b_reuse = 1;
    29.     setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, &b_reuse, sizeof (int));
    32.     /*2. 绑定 */
    33.     /*2.1 填充struct sockaddr_in结构体变量 */
    34.     bzero (&sin, sizeof (sin));
    35.     sin.sin_family = AF_INET;
    36.     sin.sin_port = htons (SERV_PORT);    //网络字节序的端口号
    38.     /*优化1: 让服务器程序能绑定在任意的IP上 */
    39. #if 1
    40.     sin.sin_addr.s_addr = htonl (INADDR_ANY);
    41. #else
    42.     if (inet_pton (AF_INET, SERV_IP_ADDR, (void *) &sin.sin_addr) != 1) {
    43.         perror ("inet_pton");
    44.         exit (1);
    45.     }
    46. #endif
    47.     /*2.2 绑定 */
    48.     if (bind (fd, (struct sockaddr *) &sin, sizeof (sin)) < 0) {
    49.         perror ("bind");
    50.         exit (1);
    51.     }
    53.     /*3. 调用listen()把主动套接字变成被动套接字 */
    54.     if (listen (fd, BACKLOG) < 0) {
    55.         perror ("listen");
    56.         exit (1);
    57.     }
    58.     printf ("Server starting....OK!\n");
    59.     int newfd = -1;
    60.     /*4. 阻塞等待客户端连接请求 */
    62.         struct sockaddr_in cin;
    63.         socklen_t addrlen = sizeof (cin);
    64.         while(1) {
    65.                 pid_t pid = -1;
    66.                 if ((newfd = accept (fd, (struct sockaddr *) &cin, &addrlen)) < 0) {
    67.                     perror ("accept");
    68.                     break;
    69.                 }
    70.         /*创建一个子进程用于处理已建立连接的客户的交互数据*/
    71.         if((pid = fork()) < 0) {
    72.             perror("fork");
    73.             break;
    74.         }
    76.         if(0 == pid) {  //子进程中
    77.             close(fd);
    78.             char ipv4_addr[16];
    80.             if (!inet_ntop (AF_INET, (void *) &cin.sin_addr, ipv4_addr, sizeof (cin))) {
    81.                             perror ("inet_ntop");
    82.                             exit (1);
    83.                         }
    85.                         printf ("Clinet(%s:%d) is connected!\n", ipv4_addr, ntohs(cin.sin_port));    
    86.             cli_data_handle(&newfd);        
    87.             return 0;    
    89.         } else { //实际上此处 pid >0, 父进程中 
    90.             close(newfd);
    91.         }
    94.     }        
    97.     close (fd);
    98.     return 0;
    99. }
    101. void cli_data_handle (void *arg)
    102. {
    103.     int newfd = *(int *) arg;
    105.     printf ("Child handling process: newfd =%d\n", newfd);
    107.     //..和newfd进行数据读写
    109.     int ret = -1;
    110.     char buf[BUFSIZ];
    111.     char resp_buf[BUFSIZ+10];
    112.     while (1) {
    113.         bzero (buf, BUFSIZ);
    114.         do {
    115.             ret = read (newfd, buf, BUFSIZ - 1);
    116.         } while (ret < 0 && EINTR == errno);
    117.         if (ret < 0) {
    119.             perror ("read");
    120.             exit (1);
    121.         }
    122.         if (!ret) {                //对方已经关闭
    123.             break;
    124.         }
    125.         printf ("Receive data: %s\n", buf);
    127.         bzero(resp_buf,BUFSIZ+10);
    128.         strncpy(resp_buf,SERV_RESP_STR,strlen(SERV_RESP_STR));
    129.         strcat(resp_buf,buf);
    131.         do{
    132.             write(newfd,resp_buf,strlen(resp_buf));    
    133.         }while(ret<0 && EINTR ==errno);
    135.         if (!strncasecmp (buf, QUIT_STR, strlen (QUIT_STR))) {    //用户输入了quit字符
    136.             printf ("Client(fd=%d) is exiting!\n", newfd);
    137.             break;
    138.         }
    140.         bzero(resp_buf, BUFSIZ+10);
    142.         strncpy(resp_buf, SERV_RESP_STR, strlen(SERV_RESP_STR));
    143.         strcat(resp_buf, buf);     
    144.         do {
    145.             ret = write(newfd, resp_buf, strlen(resp_buf));    
    146.         }while(ret < 0 && EINTR == errno);
    148.     }
    149.     close (newfd);
    151. }