xref: /freebsd/bin/hostname/hostname.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e)
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static char const copyright[] =
36 "@(#) Copyright (c) 1988, 1993\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 #if 0
42 static char sccsid[] = "@(#)hostname.c	8.1 (Berkeley) 5/31/93";
43 #endif
44 static const char rcsid[] =
45   "$FreeBSD$";
46 #endif /* not lint */
47 
48 #include <sys/param.h>
49 
50 #include <err.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 
56 void usage __P((void));
57 
58 int
59 main(argc,argv)
60 	int argc;
61 	char *argv[];
62 {
63 	int ch, sflag;
64 	char *p, hostname[MAXHOSTNAMELEN];
65 
66 	sflag = 0;
67 	while ((ch = getopt(argc, argv, "s")) != -1)
68 		switch (ch) {
69 		case 's':
70 			sflag = 1;
71 			break;
72 		case '?':
73 		default:
74 			usage();
75 		}
76 	argc -= optind;
77 	argv += optind;
78 
79 	if (argc > 1)
80 		usage();
81 
82 	if (*argv) {
83 		if (sethostname(*argv, strlen(*argv)))
84 			err(1, "sethostname");
85 	} else {
86 		if (gethostname(hostname, sizeof(hostname)))
87 			err(1, "gethostname");
88 		if (sflag && (p = strchr(hostname, '.')))
89 			*p = '\0';
90 		(void)printf("%s\n", hostname);
91 	}
92 	exit(0);
93 }
94 
95 void
96 usage()
97 {
98 
99 	(void)fprintf(stderr, "usage: hostname [-s] [name-of-host]\n");
100 	exit(1);
101 }
102