hostname.c

/* vi: set sw=4 ts=4: */
/*
 * $Id: hostname.c,v 1.28 2001/05/16 15:40:48 kraai Exp $
 * Mini hostname implementation for busybox
 *
 * Copyright (C) 1999 by Randolph Chung <tausq@debian.org>
 *
 * adjusted by Erik Andersen <andersee@debian.org> to remove
 * use of long options and GNU getopt.  Improved the usage info.
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "busybox.h"
#include <errno.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

static void do_sethostname(char *s, int isfile)
{
	FILE *f;
	char buf[255];

	if (!s)
		return;
	if (!isfile) {
		if (sethostname(s, strlen(s)) < 0) {
			if (errno == EPERM)
				error_msg_and_die("you must be root to change the hostname");
			else
				perror_msg_and_die("sethostname");
		}
	} else {
		f = xfopen(s, "r");
		fgets(buf, 255, f);
		fclose(f);
		chomp(buf);
		if (sethostname(buf, strlen(buf)) < 0)
			perror_msg_and_die("sethostname");
	}
}

int hostname_main(int argc, char **argv)
{
	int opt_short = 0;
	int opt_domain = 0;
	int opt_ip = 0;
	struct hostent *h;
	char *filename = NULL;
	char buf[255];
	char *s = NULL;

	if (argc < 1)
		show_usage();

	while (--argc > 0 && **(++argv) == '-') {
		while (*(++(*argv))) {
			switch (**argv) {
			case 's':
				opt_short = 1;
				break;
			case 'i':
				opt_ip = 1;
				break;
			case 'd':
				opt_domain = 1;
				break;
			case 'F':
				if (--argc == 0) {
					show_usage();
				}
				filename = *(++argv);
				break;
			case '-':
				if (strcmp(++(*argv), "file") || --argc ==0 ) {
					show_usage();
				}
				filename = *(++argv);
				break;
			default:
				show_usage();
			}
			if (filename != NULL)
				break;
		}
	}

	if (argc >= 1) {
		do_sethostname(*argv, 0);
	} else if (filename != NULL) {
		do_sethostname(filename, 1);
	} else {
		gethostname(buf, 255);
		if (opt_short) {
			s = strchr(buf, '.');
			if (!s)
				s = buf;
			*s = 0;
			puts(buf);
		} else if (opt_domain) {
			s = strchr(buf, '.');
			puts(s ? s + 1 : "");
		} else if (opt_ip) {
			h = xgethostbyname(buf);
			puts(inet_ntoa(*(struct in_addr *) (h->h_addr)));
		} else {
			puts(buf);
		}
	}
	return(0);
}