/*
 * Copyright (c) 2001 Fenris, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * File:  resolver.c
 *
 * Purpose:  This source file...
 *
 */

#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <string.h>
#include <unistd.h>
#include <setjmp.h>
#include <signal.h>
#include <errno.h>

#include "cache_list.h"
#include "globals.h"
#include "resolver.h"

#define MMAX(a, b)       (((a) < (b)) ? (b) : (a))
#define MMIN(a, b)       (((a) > (b)) ? (b) : (a))

jmp_buf resolver_env;


void nohostname(int signo)
{
    longjmp(resolver_env, 1);
    /* NOTREACHED */
}


int main(int argc, char *argv[])
{
    unsigned char       *name;
    Name_Obj            *obj;
    struct hostent      *hp;
    unsigned char        msg[MMAX(NET_TO_RSLV_LEN, RSLV_TO_NET_LEN)];
    int                  rcvd;
    int                  len;
    unsigned int         addr;

    if ((hp = malloc(sizeof(struct hostent))) == NULL)
        die("malloc");

    for (;;) {
        len = 0;
        do {
            if ((rcvd = read(0, &msg + len, NET_TO_RSLV_LEN - len)) == -1)
                die("read");
            len += rcvd;
        } while (len < NET_TO_RSLV_LEN);

        addr = msg[1];
        addr <<= 8;
        addr += msg[2];
        addr <<= 8;
        addr += msg[3];
        addr <<= 8;
        addr += msg[4];
        addr = htonl(addr);

        if (!setjmp(resolver_env)) {
            signal(SIGALRM, nohostname);
            alarm(1);
            hp = gethostbyaddr((char *)&addr, 4, AF_INET);
            alarm(0);
        } else {
            hp = NULL;
        }

        if (hp != NULL) {
            len = MMIN(strlen(hp->h_name), MAX_HOSTNAME_LEN - 1);
            memcpy(msg + NET_TO_RSLV_LEN, hp->h_name, len);
            msg[NET_TO_RSLV_LEN + len] = '\0';

            if (write(1, msg, RSLV_TO_NET_LEN) == -1)
                die("write");
        }
    }

    return 0;
}