xref: /freebsd/bin/hostname/hostname.c (revision 640235e2c2ba32947f7c59d168437ffa1280f1e6)
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
32 static 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
38 static char sccsid[] = "@(#)hostname.c	8.1 (Berkeley) 5/31/93";
39 #endif /* not lint */
40 #endif
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
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 
52 static void usage(void) __dead2;
53 
54 int
55 main(int argc, char *argv[])
56 {
57 	int ch, sflag;
58 	char *p, hostname[MAXHOSTNAMELEN];
59 
60 	sflag = 0;
61 	while ((ch = getopt(argc, argv, "fs")) != -1)
62 		switch (ch) {
63 		case 'f':
64 			/*
65 			 * On Linux, "hostname -f" prints FQDN.
66 			 * BSD "hostname" always prints FQDN by
67 			 * default, so we accept but ignore -f.
68 			 */
69 			break;
70 		case 's':
71 			sflag = 1;
72 			break;
73 		case '?':
74 		default:
75 			usage();
76 		}
77 	argc -= optind;
78 	argv += optind;
79 
80 	if (argc > 1)
81 		usage();
82 
83 	if (*argv) {
84 		if (sethostname(*argv, (int)strlen(*argv)))
85 			err(1, "sethostname");
86 	} else {
87 		if (gethostname(hostname, (int)sizeof(hostname)))
88 			err(1, "gethostname");
89 		if (sflag) {
90 			p = strchr(hostname, '.');
91 			if (p != NULL)
92 				*p = '\0';
93 		}
94 		(void)printf("%s\n", hostname);
95 	}
96 	exit(0);
97 }
98 
99 static void
100 usage(void)
101 {
102 
103 	(void)fprintf(stderr, "usage: hostname [-fs] [name-of-host]\n");
104 	exit(1);
105 }
106