#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>

#define TRUE 1

/*
 * This program uses select() to check that someone is trying to connect
 * before calling accept().
 */

main()
{
     int sock, length;
     struct sockaddr_in server;
     int msgsock;
     char buf[1024];
     int rval;
     fd_set ready; 
     struct timeval to;

     /* Create socket */ 
     sock = socket(AF_INET, SOCK_STREAM, 0); 
     if (sock < 0) { 
          perror("opening stream socket"); 
          exit(1); 
     } 
     /* Name socket using wildcards */ 
     server.sin_family = AF_INET; 
     server.sin_addr.s_addr = INADDR_ANY; 
     server.sin_port = 0; 
     if (bind(sock, &server, sizeof(server))) {
          perror("binding stream socket"); 
          exit(1); 
     } 
     /* Find out assigned port number and print it out */ 
     length = sizeof(server); 
     if (getsockname(sock, &server, &length)) { 
          perror("getting socket name"); 
          exit(1); 
     } 
     printf("Socket has port #%d\n", ntohs(server.sin_port));
     /* Start accepting connections */ 
     listen(sock, 5); 
     do { 
          FD_ZERO(&ready); 
          FD_SET(sock, &ready); 
          to.tv_sec = 5;
          if (select(sock + 1, &ready, 0, 0, &to) < 0) {
               perror("select");
               continue;
          }
          if (FD_ISSET(sock, &ready)) {
               msgsock = accept(sock, (struct sockaddr *)0, (int *)0);
               if (msgsock == -1)
                    perror("accept");
               else do {
                    bzero(buf, sizeof(buf));
                    if ((rval = read(msgsock, buf, 1024)) < 0)
                         perror("reading stream message");
                    else if (rval == 0)
                         printf("Ending connection\n");
                    else
                         printf("-->%s\n", buf);
               } while (rval > 0);
               close(msgsock);
          } else
               printf("Do something else\n");
     } while (TRUE);
}