int main(int argc, char *argv[])
{
   int listenfd, connfd;
   pid_t childp;
   socklen_t clientlen;
   struct sockaddr_in server, client;
   
   if (argc != 2) {
      printf("USAGE: <port>\n");
      exit(1);
   }
   
   /* create initial socket */
   listenfd = Socket(AF_INET, SOCK_STREAM, 0);

   /* set socket info */
   memset(&server, '\0', sizeof(server));
   server.sin_family = AF_INET;
   server.sin_addr.s_addr = htonl(INADDR_ANY);
   server.sin_port = htons(atoi(argv[1]));
   
   /* binds */
   Bind(listenfd, (struct sockaddr *) &server, sizeof(server));
   /* and listen */
   Listen(listenfd, 5);

   printf("Listening on port %d...\n", atoi(argv[1]));
      
   /* signal handler */
   signal(SIGCHLD, sig_chld);
   
   /* child process loop */
   for ( ; ; ) {
      clientlen = sizeof(client);
      printf("!");
      if ((connfd = accept(listenfd, (struct sockaddr *) &client, &clientlen)) < 0) {
         if (errno == EINTR)
            continue;
         else 
            perror("accept error");
      }
      if ((childp = fork()) == 0) { /* child process */
         close(listenfd);
         str_echo(connfd);
         exit(0);
      } else if (childp == -1)
         perror("fork");
         
      close(connfd);         
   }
}

main(int argc, char *argv[])
{
   int i, sockfd;
   struct sockaddr_in server;
   
   if (argc != 3) {
      printf("USAGE: <ip address> <port> <# of connections>\n");
      exit(1);
   }      
   
   if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
      perror("socket");
      exit(1);
   }
      
   memset(&server, '\0', sizeof(server));
   server.sin_family = AF_INET;
   server.sin_port = htons(atoi(argv[2]));
   server.sin_addr.s_addr = inet_aton(argv[1]);
      
   printf("Attempting connection to %s\n",argv[1]);
   if (connect(sockfd, (struct sockaddr *) &server, sizeof(server)) == -1) {
      perror("connect");
      exit(1);
   }
   
   str_cli(stdin, sockfd);
   exit(0);
}