xref: /minix3/usr.bin/tty/tty.c (revision b828b0feb732ef318fcb70b8f54b02747c03962a)
1 /*	$NetBSD: tty.c,v 1.8 2011/09/06 18:34:57 joerg 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\
35  The Regents of the University of California.  All rights reserved.");
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 1.8 2011/09/06 18:34:57 joerg Exp $");
43 #endif /* not lint */
44 
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <unistd.h>
48 
49 __dead static void usage(void);
50 
51 int
main(int argc,char ** argv)52 main(int argc, char **argv)
53 {
54 	int ch, sflag;
55 	char *t;
56 
57 	sflag = 0;
58 	while ((ch = getopt(argc, argv, "s")) != -1) {
59 		switch((char)ch) {
60 		case 's':
61 			sflag = 1;
62 			break;
63 		case '?':
64 		default:
65 			usage();
66 			/* NOTREACHED */
67 		}
68 	}
69 
70 	t = ttyname(STDIN_FILENO);
71 	if (!sflag)
72 		puts(t ? t : "not a tty");
73 	exit(t ? 0 : 1);
74 }
75 
76 static void
usage(void)77 usage(void)
78 {
79 	fprintf(stderr, "usage: tty [-s]\n");
80 	exit(2);
81 }
82