服务器与客户端 李敏敏

院系：计算机与信息工程学院

班级：09级计算机应用2班

姓名：李敏敏

学号：0906042023

 

 

服务器——客户端

/*****************server.c******************/

#include

#include

#include

#include

#include "wrap.h"

 

#define MAXLINE 80

#define SERV_PORT 8000

 

int main(int argc, char **argv)

{

    int i, maxi, maxfd, listenfd, connfd, sockfd;

    int nready, client[FD_SETSIZE];

    ssize_t n;

    fd_set rset, allset;

    char buf[MAXLINE];

    char str[INET_ADDRSTRLEN];

    socklen_t cliaddr_len;

    struct sockaddr_in cliaddr, servaddr;

   

int j;

 

    listenfd = Socket(AF_INET, SOCK_STREAM, 0);

 

    bzero(&servaddr, sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    servaddr.sin_port = htons(SERV_PORT);

 

    Bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));//绑定

 

    Listen(listenfd, 20);

 

    maxfd = listenfd;    /* initialize */

    maxi = -1;        /* index into client[] array */

    for (i = 0; i < FD_SETSIZE; i++)

        client[i] = -1;    /* -1 indicates available entry */

    FD_ZERO(&allset);//清零

    FD_SET(listenfd, &allset);添加

 

    for (;;) {

        rset = allset;    /* structure assignment */

        nready = select(maxfd + 1, &rset, NULL, NULL, NULL);//查看是否有可读数据

        if (nready < 0)

            perr_exit("select error");

 

        if (FD_ISSET(listenfd, &rset)) {    /* new client connection */

            cliaddr_len = sizeof(cliaddr);

            connfd = Accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);

 

            printf("received from %s at PORT %d\n", inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)), ntohs(cliaddr.sin_port));

 

            for (i = 0; i < FD_SETSIZE; i++)

                if (client[i] < 0) {

                    client[i] = connfd;    /* save descriptor */

                    break;

                }

            if (i == FD_SETSIZE) {

                fputs("too many clients\n", stderr);

                exit(1);

            }

 

            FD_SET(connfd, &allset);    /* add new descriptor to set */

            if (connfd > maxfd)

                maxfd = connfd;    /* for select */

            if (i > maxi)

                maxi = i;    /* max index in client[] array */

 

            if (--nready == 0)

                continue;    /* no more readable descriptors */

        }

 

        for (i = 0; i <= maxi; i++) {    /* check all clients for data */

            if ((sockfd = client[i]) < 0)

                continue;

            if (FD_ISSET(sockfd, &rset)) {

                if ((n = Read(sockfd, buf, MAXLINE)) < 0) {    //读取客户端发送的内容

                    /*connection closed by client */

                    Close(sockfd);                               //如果读取失败则关闭连接

                    FD_CLR(sockfd, &allset);                   //把这个文件描述符从连接中清除

                    client[i] = -1;                            //把客户端标志设为-1

                } else {

 

                  

                    for (j = 0; j <= maxi; j++) {

                        if (FD_ISSET(sockfd, &rset))

                               {

                                 if(sockfd!=client[j]);

                                 Write(client[j], buf, n);   

                                }

        //把已读到的数据发送给每一个连接的客户端

 

                    }

 

                }

 

                if (--nready == 0)

                    break;    /* no more readable descriptors */

            }

        }

    }

}

/**********************client.c ****************/

#include

#include

#include

#include

#include "wrap.h"

#include

#include

#include

 

#define MAXLINE 80

#define SERV_PORT 8000

 

int main(int argc, char *argv[])

{

    struct sockaddr_in servaddr;

    char buf[MAXLINE];

    int sockfd, n;

    pid_t pid;

 

    sockfd = Socket(AF_INET, SOCK_STREAM, 0);

 

    bzero(&servaddr, sizeof(servaddr));

    servaddr.sin_family = AF_INET;

    inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);

    servaddr.sin_port = htons(SERV_PORT);

 

    Connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

 

    pid = fork();                                       //分支为两个进程

 

    if (pid > 0) {        //父进程

        while (fgets(buf, MAXLINE, stdin) != NULL) {

            Write(sockfd, buf, strlen(buf));              //向客户端发送数据

        }

    }

    if (pid == 0) {        //子进程

        int b_on = 1;

        ioctl(sockfd, FIONBIO, &b_on);

        for (;;)

            if ((n = Read(sockfd, buf, MAXLINE)) > 0)     //向服务器接收数据

                Write(STDOUT_FILENO, buf, n);              //把读到的数据写进标准输出

    }

    Close(sockfd);

    return 0;

}

执行过程：

服务器：

[root@localhost ~]# cd Desktop

[root@localhost Desktop]# gcc server.c -o server

[root@localhost Desktop]# ./server

 

[root@localhost Desktop]# ./server

received from 127.0.0.1 at PORT 44816

received from 127.0.0.1 at PORT 44818

received from 127.0.0.1 at PORT 47372

 

 

打开三个客户端：

第一个：

[root@localhost Desktop]# gcc client.c -o client

[root@localhost Desktop]# ./client

wodemingzi

wodemingzi

hello     

hello

xianzaishi

xianzaishi

第二个：

[root@localhost ~]# cd Desktop

[root@localhost Desktop]# ./client

wodemingzi

hello

xianzaishi

第三个：

[root@localhost ~]# cd Desktop

[root@localhost Desktop]# ./client

xianzaizhendehenhao

xianzaizhendehenhao