#include <stdio.h>
#include <stdlib.h>

#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

static inline void die(const char *msg) {
    perror(msg);
    exit(-1);
}

int main() {
    struct sockaddr_in srv_addr, cli_addr;
    int                sockopt = 1;
    socklen_t          sad_sz  = sizeof(struct sockaddr_in);
    int                sfd, cfd;
    ssize_t            bytes;
    char               buf[256];

    srv_addr.sin_family      = AF_INET;
    srv_addr.sin_port        = htons(8000);
    srv_addr.sin_addr.s_addr = INADDR_ANY;

    if ((sfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        die("Couldn't open the socket");

    setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, (char *) &sockopt, sizeof(sockopt));

    if (bind(sfd, (struct sockaddr *) &srv_addr, sad_sz) < 0)
        die("Couldn't bind socket");

    if (listen(sfd, 1) < 0)
        die("Couldn't listen to the socket");

    cfd = accept(sfd, (struct sockaddr *) &cli_addr, &sad_sz);
    if (cfd < 0)
        die("Couldn't accept incoming connection");

    while ((bytes = read(cfd, buf, sizeof(buf))) != 0) {
        if (bytes < 0)
            die("Couldn't receive message");

        if (write(cfd, buf, bytes) < 0)
            die("Couldn't send message");
    }

    close(cfd);
    close(sfd);
    return 0;
}