xref: /original-bsd/bin/hostname/hostname.c (revision 2301fdfb)
1 /*
2  * Copyright (c) 1983, 1988 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #ifndef lint
19 char copyright[] =
20 "@(#) Copyright (c) 1983, 1988 Regents of the University of California.\n\
21  All rights reserved.\n";
22 #endif /* not lint */
23 
24 #ifndef lint
25 static char sccsid[] = "@(#)hostname.c	5.3 (Berkeley) 06/18/88";
26 #endif /* not lint */
27 
28 #include <stdio.h>
29 #include <sys/param.h>
30 
31 main(argc,argv)
32 	int argc;
33 	char **argv;
34 {
35 	extern int optind;
36 	int ch, sflag;
37 	char hostname[MAXHOSTNAMELEN], *p, *index();
38 
39 	sflag = 0;
40 	while ((ch = getopt(argc, argv, "s")) != EOF)
41 		switch((char)ch) {
42 		case 's':
43 			sflag = 1;
44 			break;
45 		case '?':
46 		default:
47 			fputs("hostname [-s] [hostname]\n", stderr);
48 			exit(1);
49 		}
50 	argv += optind;
51 
52 	if (*argv) {
53 		if (sethostname(*argv, strlen(*argv))) {
54 			perror("sethostname");
55 			exit(1);
56 		}
57 	} else {
58 		if (gethostname(hostname, sizeof(hostname))) {
59 			perror("gethostname");
60 			exit(1);
61 		}
62 		if (sflag && (p = index(hostname, '.')))
63 			*p = '\0';
64 		puts(hostname);
65 	}
66 	exit(0);
67 }
68