回射程序

回射程序：服务端将客户端发送的数据输出并返回给客户端

客户端

  1 #include "net.h"
  2 
  3 int main(int argc, char **argv)
  4 {
  5     int sockfd, n;
  6     char sendline[MAXLINE], recvline[MAXLINE + 1];
  7     struct sockaddr_in servaddr;
  8 
  9     if (argc != 2)
 10     {
 11         printf("Error arg!
");
 12         exit(1);
 13     }
 14 
 15     if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 )
 16     {
 17         printf("Error socket!
");
 18         exit(1);
 19     }
 20 
 21     bzero(&servaddr, sizeof(servaddr));
 22     servaddr.sin_family = AF_INET;
 23     servaddr.sin_port = htons(SERV_PORT);
 24 
 25     if (inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0)
 26     {
 27         printf("Error inet_pton!
");
 28         exit(1);
 29     }
 30 
 31     if (connect(sockfd, (SA *) &servaddr, sizeof(servaddr)) < 0)
 32     {
 33         printf("Error connect!
");
 34         exit(1);
 35     }
 36 
 37     printf("Success init!
");
 38 
 39     while (fgets(sendline, MAXLINE, stdin) != NULL)
 40     {
 41         printf("Success fget from stdin!
");
 42 
 43         if (write(sockfd, sendline, strlen(sendline)) < 0)
 44         {
 45             printf("Error write!
");
 46             exit(1);
 47         }
 48 
 49         if ( (n = read(sockfd, recvline, MAXLINE)) > 0 )
 50         {
 51             recvline[n] = '';
 52             fputs(recvline, stdout);
 53         }
 54     }
 55 
 56     return 0;
 57 }

服务端

服务端：
  1 #include "net.h"
  2 
  3 int main(int argc, char **argv)
  4 {
  5     int listenfd, connfd, n;
  6     struct sockaddr_in servaddr, cliaddr;
  7     char buff[MAXLINE];
  8     pid_t childpid;
  9     socklen_t clilen;
 10 
 11     if ( (listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 )
 12     {
 13         printf("Error socket!
");
 14         exit(0);
 15     }
 16 
 17     bzero(&servaddr, sizeof(servaddr));
 18     servaddr.sin_family = AF_INET;
 19     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 20     servaddr.sin_port = htons(SERV_PORT);
 21 
 22     if (bind(listenfd, (SA *) &servaddr, sizeof(servaddr)) < 0)
 23     {
 24         printf("Error bind!
");
 25         exit(1);
 26     }
 27 
 28     if (listen(listenfd, LISTENQ) < 0)
 29     {
 30         printf("Error listen!
");
 31         exit(1);
 32     }
 33 
 34     printf("Success init!
");
 35 
 36     for ( ; ; )
 37     {
 38         clilen = sizeof(cliaddr);
 39 
 40         if ( (connfd = accept(listenfd, (SA *) &cliaddr, &clilen)) < 0 )
 41         {
 42             printf("Error accept!
");
 43             exit(0);
 44         }
 45 
 46         if ( (childpid = fork()) == 0 )
 47         {
 48             if (close(listenfd) < 0)
 49             {
 50                 printf("Error close!
");
 51                 exit(1);
 52             }
 53 
 54             while ( (n = read(connfd, buff, MAXLINE)) > 0 )
 55             {
 56                 buff[n] = '';
 57                 fputs(buff, stdout);
 58 
 59                 if (write(connfd, buff, strlen(buff)) < 0)
 60                 {
 61                     printf("Error write!
");
 62                     exit(1);
 63                 }
 64             }
 65 
 66             exit(0);
 67         }
 68     }
 69 }

运行结果:

[wangml@iZwz976helaylvgqok97prZ net]$ ./chat_cli 120.24.55.49
Success init!
qwer
Success fget from stdin!
qwer
sds
Success fget from stdin!
sds

Success fget from stdin!

^C

[root@iZwz976helaylvgqok97prZ net]# ./chat_ser 
Success init!
qwer
sds

^C