#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <signal.h>
#include <math.h>
#include <string.h>


int main(int argc, char *argv[])
{
	int is_addr;
	struct hostent *hn;
	int i;
	struct in_addr addr;

	if(argc < 2)
	{
		fprintf(stderr,"usages: my_dns2 dns_name\nmy_dns2 ip_addr\n");
		fflush(stderr);
		exit(1);
	}

	/*
	 * first, try to make an ip address out of the string passed as the
	 * first argument
	 */
#ifdef sun
	is_addr = inet_addr(argv[1]);
	if(is_addr == -1)
	{
		is_addr = 0;
	}
	else
	{
		memcpy(&addr,&is_addr,sizeof(addr));
		is_addr = 1;
	}
#else
	is_addr = inet_aton(argv[1],&addr);
#endif

	/*
	 * if this worked, argv[1] is a dotted notation IP address =>
	 * gethostbyaddr()
	 */
	if(is_addr)
	{
		hn = gethostbyaddr((char *)&addr, sizeof(addr), AF_INET);
		if(hn == NULL)
		{
			fprintf(stderr,"gethostbyaddr() failed for %s\n",
					argv[1]);
			fflush(stderr);
			exit(1);
		}
	}
	else
	{
		hn = gethostbyname(argv[1]);
		if(hn == NULL)
		{
			fprintf(stderr,"gethostbyname() failed for %s\n",
					argv[1]);
			fflush(stderr);
			exit(1);
		}
	}


	/*
	 * print its official host name
	 */
	fprintf(stdout,"host name: %s\n",hn->h_name);

	/*
	 * loop through the alias list
	 */
	i = 0;
	while(hn->h_aliases[i] != NULL)
	{
		fprintf(stdout,"alias: %s\n",hn->h_aliases[i]);
		i++;
	}

	/*
	 * loop through address list
	 */
	i = 0;
	while(hn->h_addr_list[i] != NULL)
	{
		/*
		 * this is ugly -- inet_ntoa() takes a structure as a value
		 * parameter
		 *
		 * plase don't ever do this
		 */
		memcpy(&addr,hn->h_addr_list[i],sizeof(addr));
		fprintf(stdout,"address: %s\n", inet_ntoa(addr));
		i++;
	}

	return(0);
}