ser.c

#include <pthread.h>
#include <signal.h>
#include "net.h"

void cli_data_handle (void *arg);

void sig_child_handle(int signo)
{
    if(SIGCHLD == signo) {
        waitpid(-1, NULL,  WNOHANG);
    }
}
int main (void)
{

    int fd = -1;
    struct sockaddr_in sin;

    signal(SIGCHLD, sig_child_handle);    

    /* 1. 创建socket fd */
    if ((fd = socket (AF_INET, SOCK_STREAM, 0)) < 0) {
        perror ("socket");
        exit (1);
    }

    /*优化4： 允许绑定地址快速重用 */
    int b_reuse = 1;
    setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, &b_reuse, sizeof (int));


    /*2. 绑定 */
    /*2.1 填充struct sockaddr_in结构体变量 */
    bzero (&sin, sizeof (sin));
    sin.sin_family = AF_INET;
    sin.sin_port = htons (SERV_PORT);    //网络字节序的端口号

    /*优化1: 让服务器程序能绑定在任意的IP上 */
#if 1
    sin.sin_addr.s_addr = htonl (INADDR_ANY);
#else
    if (inet_pton (AF_INET, SERV_IP_ADDR, (void *) &sin.sin_addr) != 1) {
        perror ("inet_pton");
        exit (1);
    }
#endif
    /*2.2 绑定 */
    if (bind (fd, (struct sockaddr *) &sin, sizeof (sin)) < 0) {
        perror ("bind");
        exit (1);
    }

    /*3. 调用listen()把主动套接字变成被动套接字 */
    if (listen (fd, BACKLOG) < 0) {
        perror ("listen");
        exit (1);
    }
    printf ("Server starting....OK!\n");
    int newfd = -1;
    /*4. 阻塞等待客户端连接请求 */

        struct sockaddr_in cin;
        socklen_t addrlen = sizeof (cin);
    while(1) {
        pid_t pid = -1;
        if ((newfd = accept (fd, (struct sockaddr *) &cin, &addrlen)) < 0) {
                        perror ("accept");
                        break;
                }
        /*创建一个子进程用于处理已建立连接的客户的交互数据*/
        if((pid = fork()) < 0) {
            perror("fork");
            break;
        }

        if(0 == pid) {  //子进程中
            close(fd);
            char ipv4_addr[16];

            if (!inet_ntop (AF_INET, (void *) &cin.sin_addr, ipv4_addr, sizeof (cin))) {
                            perror ("inet_ntop");
                            exit (1);
                        }

                        printf ("Clinet(%s:%d) is connected!\n", ipv4_addr, ntohs(cin.sin_port));    
            cli_data_handle(&newfd);        
            return 0;    

        } else { //实际上此处 pid >0, 父进程中 
            close(newfd);
        }


    }        


    close (fd);
    return 0;
}

void cli_data_handle (void *arg)
{
    int newfd = *(int *) arg;

    printf ("Child handling process: newfd =%d\n", newfd);

    //..和newfd进行数据读写
    int ret = -1;
    char buf[BUFSIZ];
    while (1) {
        bzero (buf, BUFSIZ);
        do {
            ret = read (newfd, buf, BUFSIZ - 1);
        } while (ret < 0 && EINTR == errno);
        if (ret < 0) {

            perror ("read");
            exit (1);
        }
        if (!ret) {                //对方已经关闭
            break;
        }
        printf ("Receive data: %s\n", buf);

        if (!strncasecmp (buf, QUIT_STR, strlen (QUIT_STR))) {    //用户输入了quit字符
            printf ("Client(fd=%d) is exiting!\n", newfd);
            break;
        }
    }
    close (newfd);

}