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/* ----------------------------------------------------------------------- *
*
* Copyright 2001-2008 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., 53 Temple Place Ste 330,
* Boston MA 02111-1307, 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;
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) {
printf("%s%u.%u.%u.%u", sep,
((unsigned char *)host->h_addr)[0],
((unsigned char *)host->h_addr)[1],
((unsigned char *)host->h_addr)[2],
((unsigned char *)host->h_addr)[3]);
sep = " ";
}
if (output & 4) {
printf("%s%02X%02X%02X%02X", sep,
((unsigned char *)host->h_addr)[0],
((unsigned char *)host->h_addr)[1],
((unsigned char *)host->h_addr)[2],
((unsigned char *)host->h_addr)[3]);
sep = " ";
}
putchar('\n');
}
return err;
}
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