xref: /openbsd/usr.bin/tty/tty.c (revision 7b36286a)
1 /*	$OpenBSD: tty.c,v 1.5 2003/06/10 22:20:53 deraadt Exp $	*/
2 /*	$NetBSD: tty.c,v 1.4 1994/12/07 00:46:57 jtc Exp $	*/
3 
4 /*
5  * Copyright (c) 1988, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #ifndef lint
34 static char copyright[] =
35 "@(#) Copyright (c) 1988, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)tty.c	8.1 (Berkeley) 6/6/93";
42 #endif
43 static char rcsid[] = "$OpenBSD: tty.c,v 1.5 2003/06/10 22:20:53 deraadt Exp $";
44 #endif /* not lint */
45 
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <unistd.h>
49 
50 static void usage(void);
51 
52 int
53 main(int argc, char *argv[])
54 {
55 	int ch, sflag;
56 	char *t;
57 
58 	sflag = 0;
59 	while ((ch = getopt(argc, argv, "s")) != -1) {
60 		switch((char)ch) {
61 		case 's':
62 			sflag = 1;
63 			break;
64 		case '?':
65 		default:
66 			usage();
67 			/* NOTREACHED */
68 		}
69 	}
70 
71 	t = ttyname(STDIN_FILENO);
72 	if (!sflag)
73 		puts(t ? t : "not a tty");
74 	exit(t ? 0 : 1);
75 }
76 
77 
78 static void
79 usage(void)
80 {
81 	fprintf(stderr, "usage: tty [-s]\n");
82 	exit(2);
83 }
84