usr.bin/tty/tty.c

   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
  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
  77 usage(void)
  78 {
  79         fprintf(stderr, "usage: tty [-s]\n");
  80         exit(2);
  81 }