/* Compile with: gcc -lnsl -o getip getip.c
 *
 * This utility is written because of the lack of utility returning IP 
 * address from hostname regardless of name service used, hosts table,
 * NIS, or DNS. arp comes close, but it does not return all IPs a hostname
 * is associated. 
 *
 * March 1999, fengyue@bluerose.windmoon.nu pointed out that stdio.h needs 
 * to be included for NULL, and host_ent needs to be tested for NULL before
 * using. 
 *
 * Feburary 1998, put on network.
 *
 */
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

int
main(int argc, char **argv)
{
  const char *host_name;
  struct hostent *host_ent;
  char **host_list;
  struct in_addr *host_number;
  char *host_ip;
  int i;

  if (argc == 1) {
    printf("\n");
    printf("getip hostname1 hostname2 ...\n");
    printf("\n");
    printf("Example: \n");
    printf("# getip wind moon windmoon sun\n");
    printf("12.5.8.11\n");
    printf("12.5.8.12 12.5.8.13\n");
    printf("unknown_host\n");
    printf("12.5.8.14\n");
    printf("\n");
    printf("Send comments to mwang@mindspring.com (Michael Wang).\n");
    printf("\n");
    exit(100);
  }

  while ( --argc > 0 ) {
    host_name = *++argv;
    host_ent = gethostbyname(host_name);
    if ( host_ent != NULL ) {
      host_list = host_ent->h_addr_list;
      i=0;
      while ( (host_number = (struct in_addr *) *host_list++ ) != NULL ) {
          host_ip = inet_ntoa(*host_number);
          if ( i != 0 ) {
            printf(" ");
          }
          printf("%s", host_ip);
          i++;
      }
      printf("\n");
    } else {
      printf("unknown_host\n");
    }
  }
}