xref: /netbsd-src/usr.bin/tty/tty.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: tty.c,v 1.6 2003/08/07 11:16:51 agc Exp $	*/
2 
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  * 3. 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 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1988, 1993\n\
35 	The Regents of the University of California.  All rights reserved.\n");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)tty.c	8.1 (Berkeley) 6/6/93";
41 #endif
42 __RCSID("$NetBSD: tty.c,v 1.6 2003/08/07 11:16:51 agc Exp $");
43 #endif /* not lint */
44 
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <unistd.h>
48 
49 int	main __P((int, char **));
50 static void usage	__P((void));
51 
52 int
53 main(argc, argv)
54 	int argc;
55 	char **argv;
56 {
57 	int ch, sflag;
58 	char *t;
59 
60 	sflag = 0;
61 	while ((ch = getopt(argc, argv, "s")) != -1) {
62 		switch((char)ch) {
63 		case 's':
64 			sflag = 1;
65 			break;
66 		case '?':
67 		default:
68 			usage();
69 			/* NOTREACHED */
70 		}
71 	}
72 
73 	t = ttyname(STDIN_FILENO);
74 	if (!sflag)
75 		puts(t ? t : "not a tty");
76 	exit(t ? 0 : 1);
77 }
78 
79 
80 static void
81 usage ()
82 {
83 	fprintf(stderr, "usage: tty [-s]\n");
84 	exit(2);
85 }
86