books/tcpv1/day-time/daytimetcpcli.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <unistd.h>
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <arpa/inet.h>
   8
   9 #define MAXLINE 4096
  10
  11 int main(int argc, char *argv[])
  12 {
  13         int sockfd, err, n;
  14         char recvline[MAXLINE +1];
  15         struct sockaddr_in servaddr;
  16
  17         if (argc != 2) {
  18                 fprintf(stderr, "usage: a.out <IP address>");
  19                 exit(1);
  20         }
  21
  22         sockfd = socket(AF_INET, SOCK_STREAM, 0);
  23         if (sockfd < 0) {
  24                 perror("socket()");
  25                 exit(1);
  26         }
  27
  28         memset(&servaddr, 0, sizeof(servaddr));
  29         servaddr.sin_family = AF_INET;
  30         servaddr.sin_port   = htons(13);
  31         err = inet_pton(AF_INET, argv[1], &servaddr.sin_addr);
  32         if (err < 0) {
  33                 perror("inet_pton()");
  34                 close(sockfd);
  35                 exit(1);
  36         }
  37
  38         err = connect(sockfd, (struct sockaddr *) &servaddr,
  39                       sizeof(servaddr));
  40         if (err < 0) {
  41                 perror("connect()");
  42                 close(sockfd);
  43                 exit(1);
  44         }
  45
  46         while ( (n = read(sockfd, recvline, MAXLINE) ) > 0) {
  47                 recvline[n] = '\0'; /* NULL terminate */
  48                 if (fputs(recvline, stdout) == EOF)
  49                         perror("fputs()");
  50         }
  51         if (n < 0)
  52                 perror("read()");
  53
  54         exit(0);
  55 }