/* Author: Kees Cook <kees@ubuntu.com>
 * Copyright 2011 Canonical, Ltd
 * License: GPLv2
 */
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <stdint.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <netdb.h>
#include <errno.h>
#include <netinet/in.h>

#define PORT 12345

int main(int argc, char * argv[])
{
    struct sigaction reaper;
    struct protoent *proto;
    struct sockaddr_in saddr;
    int server, on=1;
    char cmd[80];

    if (!(proto=getprotobyname("tcp"))) {
        perror("getprotobyname");
        return 1;
    }
    if ((server = socket(PF_INET, SOCK_STREAM, proto->p_proto))<0) {
        perror("socket");
        return 1;
    }
    if (setsockopt(server, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0) {
        perror("setsockopt");
        return 1;
    }

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

    if (bind(server, (struct sockaddr *) &saddr, sizeof(saddr)) < 0) {
        perror("bind");
        return 1;
    }
    if (listen(server,5)<0) {
        perror("listen");
        return 1;
    }


    printf("parent: %d\n", getpid());

    printf("before:\n");
    sprintf(cmd, "netstat -an | grep :%d", PORT);
    system(cmd);

    int pid = fork();
    if (pid == 0) {
        printf("child: %d\n", getpid());
        sleep(100);
        exit(0);
    }
    shutdown(server, SHUT_RDWR);

    printf("after:\n");
    system(cmd);

    return 0;
}