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

#define PORT        3452
#define BUFLEN      1024

void main()
{
    int i;
    int rc;
    int s;
    int cs;
    char buf[BUFLEN+1];
    struct sockaddr_in  sa;
    struct sockaddr_in  csa;
    int size_csa;
    fd_set rfd;
    fd_set c_rfd;
    int dsize;

    memset(&sa, 0, sizeof(sa));
    sa.sin_family = AF_INET;
    sa.sin_port = htons(PORT);
    sa.sin_addr.s_addr = INADDR_ANY;

    s = socket(AF_INET, SOCK_STREAM, 0);
    if (s < 0) {
        perror("socket: allocation failed");
        exit(EXIT_FAILURE);
    }

    int option = 1;
    if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option)) < 0)
    {
        perror("Setsockopt");
        exit(EXIT_FAILURE);
    }

    rc = bind(s, (struct sockaddr *)&sa, sizeof(sa));

    if (rc) {
        perror("bind");
        exit(EXIT_FAILURE);
    }

    rc = listen(s, 5);

    if (rc) {
        perror("listen");
        exit(EXIT_FAILURE);
    }

    size_csa = sizeof(csa);

    dsize = getdtablesize();

    FD_ZERO(&rfd);
    FD_SET(s, &rfd);

    while (1){
        c_rfd = rfd;
        rc = select(dsize, &c_rfd, NULL, NULL, (struct timeval *)NULL);

        if (FD_ISSET(s, &c_rfd)) {
                cs = accept(s, (struct sockaddr *)&csa, &size_csa);

                if (cs < 0){
                    continue;
                }

            FD_SET(cs, &rfd);

            continue;
        }

        for (i = 0; i < dsize; i++){
            if (i != s && FD_ISSET(i, &c_rfd)) {
                rc = read(i, buf, BUFLEN);
                printf("%s", buf);
                if (rc == 0) {
                    close(i);
                    FD_CLR(i, &rfd);
                }
                else {
                    printf("%s", buf);
                }
            }
        }
    }
}