utils/gethostip.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2001-2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   8  *   Boston MA 02111-1307, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 /*
  14  * gethostip.c
  15  *
  16  * Small program to use gethostbyname() to print out a hostname in
  17  * hex and/or dotted-quad notation
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <netdb.h>
  23 #include <sys/socket.h>
  24 #include <unistd.h>
  25 #include <sysexits.h>
  26 #define _GNU_SOURCE             /* For getopt_long */
  27 #include <getopt.h>
  28
  29 const struct option options[] = {
  30     {"hexadecimal", 0, NULL, 'x'},
  31     {"decimal", 0, NULL, 'd'},
  32     {"dotted-quad", 0, NULL, 'd'},
  33     {"full-output", 0, NULL, 'f'},
  34     {"name", 0, NULL, 'n'},
  35     {"help", 0, NULL, 'h'},
  36     {NULL, 0, NULL, 0}
  37 };
  38
  39 const char *program;
  40
  41 void usage(int exit_code)
  42 {
  43     fprintf(stderr, "Usage: %s [-dxnf] hostname/ip...\n", program);
  44     exit(exit_code);
  45 }
  46
  47 int main(int argc, char *argv[])
  48 {
  49     int opt;
  50     int output = 0;
  51     int i;
  52     char *sep;
  53     int err = 0;
  54
  55     struct hostent *host;
  56
  57     program = argv[0];
  58
  59     while ((opt = getopt_long(argc, argv, "dxfnh", options, NULL)) != -1) {
  60         switch (opt) {
  61         case 'd':
  62             output |= 2;        /* Decimal output */
  63             break;
  64         case 'x':
  65             output |= 4;        /* Hexadecimal output */
  66             break;
  67         case 'n':
  68             output |= 1;        /* Canonical name output */
  69             break;
  70         case 'f':
  71             output = 7;         /* Full output */
  72             break;
  73         case 'h':
  74             usage(0);
  75             break;
  76         default:
  77             usage(EX_USAGE);
  78             break;
  79         }
  80     }
  81
  82     if (optind == argc)
  83         usage(EX_USAGE);
  84
  85     if (output == 0)
  86         output = 7;             /* Default output */
  87
  88     for (i = optind; i < argc; i++) {
  89         sep = "";
  90         host = gethostbyname(argv[i]);
  91         if (!host) {
  92             herror(argv[i]);
  93             err = 1;
  94             continue;
  95         }
  96
  97         if (host->h_addrtype != AF_INET || host->h_length != 4) {
  98             fprintf(stderr, "%s: No IPv4 address associated with name\n",
  99                     argv[i]);
 100             err = 1;
 101             continue;
 102         }
 103
 104         if (output & 1) {
 105             printf("%s%s", sep, host->h_name);
 106             sep = " ";
 107         }
 108
 109         if (output & 2) {
 110             printf("%s%u.%u.%u.%u", sep,
 111                    ((unsigned char *)host->h_addr)[0],
 112                    ((unsigned char *)host->h_addr)[1],
 113                    ((unsigned char *)host->h_addr)[2],
 114                    ((unsigned char *)host->h_addr)[3]);
 115             sep = " ";
 116         }
 117
 118         if (output & 4) {
 119             printf("%s%02X%02X%02X%02X", sep,
 120                    ((unsigned char *)host->h_addr)[0],
 121                    ((unsigned char *)host->h_addr)[1],
 122                    ((unsigned char *)host->h_addr)[2],
 123                    ((unsigned char *)host->h_addr)[3]);
 124             sep = " ";
 125         }
 126
 127         putchar('\n');
 128     }
 129
 130     return err;
 131 }