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#ident "$Id: gethostip.c,v 1.2 2001/12/17 02:08:56 hpa Exp $"
/* ----------------------------------------------------------------------- *
*
* Copyright 2001 H. Peter Anvin - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
* USA; either version 2 of the License, or (at your option) any later
* version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* gethostip.c
*
* Small program to use gethostbyname() to print out a hostname in
* hex and/or dotted-quad notation
*/
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <sys/socket.h>
#include <unistd.h>
#include <sysexits.h>
#define _GNU_SOURCE /* For getopt_long */
#include <getopt.h>
const struct option options[] =
{
{ "hexadecimal", 0, NULL, 'x' },
{ "decimal", 0, NULL, 'd' },
{ "dotted-quad", 0, NULL, 'd' },
{ "full-output", 0, NULL, 'f' },
{ "name", 0, NULL, 'n' },
{ "help", 0, NULL, 'h' },
{ NULL, 0, NULL, 0 }
};
const char *program;
void usage(int exit_code)
{
fprintf(stderr, "Usage: %s [-dxnf] hostname/ip...\n", program);
exit(exit_code);
}
int main(int argc, char *argv[])
{
int opt;
int output = 0;
int i;
char *sep;
char dotquad[16];
int err = 0;
struct hostent *host;
program = argv[0];
while ( (opt = getopt_long(argc, argv, "dxfnh", options, NULL)) != -1 ) {
switch ( opt ) {
case 'd':
output |= 2; /* Decimal output */
break;
case 'x':
output |= 4; /* Hexadecimal output */
break;
case 'n':
output |= 1; /* Canonical name output */
break;
case 'f':
output = 7; /* Full output */
break;
case 'h':
usage(0);
break;
default:
usage(EX_USAGE);
break;
}
}
if ( optind == argc )
usage(EX_USAGE);
if ( output == 0 )
output = 7; /* Default output */
for ( i = optind ; i < argc ; i++ ) {
sep = "";
host = gethostbyname(argv[i]);
if ( !host ) {
herror(argv[i]);
err = 1;
continue;
}
if ( host->h_addrtype != AF_INET || host->h_length != 4 ) {
fprintf(stderr, "%s: No IPv4 address associated with name\n", argv[i]);
err = 1;
continue;
}
if ( output & 1 ) {
printf("%s%s", sep, host->h_name);
sep = " ";
}
if ( output & 2 ) {
sprintf(dotquad, "%u.%u.%u.%u",
((unsigned char *)host->h_addr)[0],
((unsigned char *)host->h_addr)[1],
((unsigned char *)host->h_addr)[2],
((unsigned char *)host->h_addr)[3]);
printf("%s%s", sep, dotquad);
sep = " ";
}
if ( output & 4 ) {
unsigned long addr =
(((unsigned char *)host->h_addr)[0] << 24UL) +
(((unsigned char *)host->h_addr)[1] << 16UL) +
(((unsigned char *)host->h_addr)[2] << 8UL) +
(((unsigned char *)host->h_addr)[3]);
printf("%s%08lX", sep, addr);
sep = " ";
}
putchar('\n');
}
return err;
}
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