1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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#ifndef lint
33static const char copyright[] =
34"@(#) 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
40static char sccsid[] = "@(#)tty.c	8.1 (Berkeley) 6/6/93";
41#endif
42#endif /* not lint */
43
44#include <sys/cdefs.h>
45__FBSDID("$FreeBSD$");
46
47#include <stdio.h>
48#include <stdlib.h>
49#include <unistd.h>
50
51static void usage(void);
52
53int
54main(int argc, char *argv[])
55{
56	int ch, sflag;
57	char *t;
58
59	sflag = 0;
60	while ((ch = getopt(argc, argv, "s")) != -1)
61		switch (ch) {
62		case 's':
63			sflag = 1;
64			break;
65		case '?':
66		default:
67			usage();
68			/* NOTREACHED */
69		}
70
71	t = ttyname(STDIN_FILENO);
72	if (!sflag)
73		puts(t ? t : "not a tty");
74	exit(t ? EXIT_SUCCESS : EXIT_FAILURE);
75}
76
77static void
78usage(void)
79{
80	fprintf(stderr, "usage: %s [-s]\n", getprogname());
81	exit(2);
82}
83