hostname.c revision 331722 
1/*-
2 * Copyright (c) 1988, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if 0
31#ifndef lint
32static char const copyright[] =
33"@(#) Copyright (c) 1988, 1993\n\
34	The Regents of the University of California.  All rights reserved.\n";
35#endif /* not lint */
36
37#ifndef lint
38static char sccsid[] = "@(#)hostname.c	8.1 (Berkeley) 5/31/93";
39#endif /* not lint */
40#endif
41#include <sys/cdefs.h>
42__FBSDID("$FreeBSD: stable/11/bin/hostname/hostname.c 331722 2018-03-29 02:50:57Z eadler $");
43
44#include <sys/param.h>
45
46#include <err.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <string.h>
50#include <unistd.h>
51
52static void usage(void) __dead2;
53
54int
55main(int argc, char *argv[])
56{
57	int ch, sflag, dflag;
58	char *p, hostname[MAXHOSTNAMELEN];
59
60	sflag = 0;
61	dflag = 0;
62	while ((ch = getopt(argc, argv, "fsd")) != -1)
63		switch (ch) {
64		case 'f':
65			/*
66			 * On Linux, "hostname -f" prints FQDN.
67			 * BSD "hostname" always prints FQDN by
68			 * default, so we accept but ignore -f.
69			 */
70			break;
71		case 's':
72			sflag = 1;
73			break;
74		case 'd':
75			dflag = 1;
76			break;
77		case '?':
78		default:
79			usage();
80		}
81	argc -= optind;
82	argv += optind;
83
84	if (argc > 1 || (sflag && dflag))
85		usage();
86
87	if (*argv) {
88		if (sethostname(*argv, (int)strlen(*argv)))
89			err(1, "sethostname");
90	} else {
91		if (gethostname(hostname, (int)sizeof(hostname)))
92			err(1, "gethostname");
93		if (sflag) {
94			p = strchr(hostname, '.');
95			if (p != NULL)
96				*p = '\0';
97		} else if (dflag) {
98			p = strchr(hostname, '.');
99			if (p != NULL)
100				strcpy(hostname, ++p);
101		}
102		(void)printf("%s\n", hostname);
103	}
104	exit(0);
105}
106
107static void
108usage(void)
109{
110
111	(void)fprintf(stderr, "usage: hostname [-f] [-s | -d] [name-of-host]\n");
112	exit(1);
113}
114