hostname.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if 0
33#ifndef lint
34static char const copyright[] =
35"@(#) Copyright (c) 1988, 1993\n\
36	The Regents of the University of California.  All rights reserved.\n";
37#endif /* not lint */
38
39#ifndef lint
40static char sccsid[] = "@(#)hostname.c	8.1 (Berkeley) 5/31/93";
41#endif /* not lint */
42#endif
43#include <sys/cdefs.h>
44__FBSDID("$FreeBSD: stable/11/bin/hostname/hostname.c 330897 2018-03-14 03:19:51Z eadler $");
45
46#include <sys/param.h>
47
48#include <err.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <string.h>
52#include <unistd.h>
53
54static void usage(void) __dead2;
55
56int
57main(int argc, char *argv[])
58{
59	int ch, sflag, dflag;
60	char *p, hostname[MAXHOSTNAMELEN];
61
62	sflag = 0;
63	dflag = 0;
64	while ((ch = getopt(argc, argv, "fsd")) != -1)
65		switch (ch) {
66		case 'f':
67			/*
68			 * On Linux, "hostname -f" prints FQDN.
69			 * BSD "hostname" always prints FQDN by
70			 * default, so we accept but ignore -f.
71			 */
72			break;
73		case 's':
74			sflag = 1;
75			break;
76		case 'd':
77			dflag = 1;
78			break;
79		case '?':
80		default:
81			usage();
82		}
83	argc -= optind;
84	argv += optind;
85
86	if (argc > 1 || (sflag && dflag))
87		usage();
88
89	if (*argv) {
90		if (sethostname(*argv, (int)strlen(*argv)))
91			err(1, "sethostname");
92	} else {
93		if (gethostname(hostname, (int)sizeof(hostname)))
94			err(1, "gethostname");
95		if (sflag) {
96			p = strchr(hostname, '.');
97			if (p != NULL)
98				*p = '\0';
99		} else if (dflag) {
100			p = strchr(hostname, '.');
101			if (p != NULL)
102				strcpy(hostname, ++p);
103		}
104		(void)printf("%s\n", hostname);
105	}
106	exit(0);
107}
108
109static void
110usage(void)
111{
112
113	(void)fprintf(stderr, "usage: hostname [-f] [-s | -d] [name-of-host]\n");
114	exit(1);
115}
116