gethostip.c

   1 #ident "$Id$"
   2 /* ----------------------------------------------------------------------- *
   3  *
   4  *   Copyright 2001-2004 H. Peter Anvin - All Rights Reserved
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   9  *   Boston MA 02111-1307, USA; either version 2 of the License, or
  10  *   (at your option) any later version; incorporated herein by reference.
  11  *
  12  * ----------------------------------------------------------------------- */
  13
  14 /*
  15  * gethostip.c
  16  *
  17  * Small program to use gethostbyname() to print out a hostname in
  18  * hex and/or dotted-quad notation
  19  */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <netdb.h>
  24 #include <sys/socket.h>
  25 #include <unistd.h>
  26 #include <sysexits.h>
  27 #define _GNU_SOURCE             /* For getopt_long */
  28 #include <getopt.h>
  29
  30 const struct option options[] =
  31 {
  32   { "hexadecimal", 0, NULL, 'x' },
  33   { "decimal",     0, NULL, 'd' },
  34   { "dotted-quad", 0, NULL, 'd' },
  35   { "full-output", 0, NULL, 'f' },
  36   { "name",        0, NULL, 'n' },
  37   { "help",        0, NULL, 'h' },
  38   { NULL, 0, NULL, 0 }
  39 };
  40
  41 const char *program;
  42
  43 void usage(int exit_code)
  44 {
  45   fprintf(stderr, "Usage: %s [-dxnf] hostname/ip...\n", program);
  46   exit(exit_code);
  47 }
  48
  49 int main(int argc, char *argv[])
  50 {
  51   int opt;
  52   int output = 0;
  53   int i;
  54   char *sep;
  55   int err = 0;
  56
  57   struct hostent *host;
  58
  59   program = argv[0];
  60
  61   while ( (opt = getopt_long(argc, argv, "dxfnh", options, NULL)) != -1 ) {
  62     switch ( opt ) {
  63     case 'd':
  64       output |= 2;              /* Decimal output */
  65       break;
  66     case 'x':
  67       output |= 4;              /* Hexadecimal output */
  68       break;
  69     case 'n':
  70       output |= 1;              /* Canonical name output */
  71       break;
  72     case 'f':
  73       output = 7;               /* Full output */
  74       break;
  75     case 'h':
  76       usage(0);
  77       break;
  78     default:
  79       usage(EX_USAGE);
  80       break;
  81     }
  82   }
  83
  84   if ( optind == argc )
  85     usage(EX_USAGE);
  86
  87   if ( output == 0 )
  88     output = 7;                 /* Default output */
  89
  90   for ( i = optind ; i < argc ; i++ ) {
  91     sep = "";
  92     host = gethostbyname(argv[i]);
  93     if ( !host ) {
  94       herror(argv[i]);
  95       err = 1;
  96       continue;
  97     }
  98
  99     if ( host->h_addrtype != AF_INET || host->h_length != 4 ) {
 100       fprintf(stderr, "%s: No IPv4 address associated with name\n", argv[i]);
 101       err = 1;
 102       continue;
 103     }
 104
 105     if ( output & 1 ) {
 106       printf("%s%s", sep, host->h_name);
 107       sep = " ";
 108     }
 109
 110     if ( output & 2 ) {
 111       printf("%s%u.%u.%u.%u", sep,
 112              ((unsigned char *)host->h_addr)[0],
 113              ((unsigned char *)host->h_addr)[1],
 114              ((unsigned char *)host->h_addr)[2],
 115              ((unsigned char *)host->h_addr)[3]);
 116       sep = " ";
 117     }
 118
 119     if ( output & 4 ) {
 120       printf("%s%02X%02X%02X%02X", sep,
 121              ((unsigned char *)host->h_addr)[0],
 122              ((unsigned char *)host->h_addr)[1],
 123              ((unsigned char *)host->h_addr)[2],
 124              ((unsigned char *)host->h_addr)[3]);
 125       sep = " ";
 126     }
 127
 128     putchar('\n');
 129   }
 130
 131   return err;
 132 }