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mesg.c revision 1.5 
      1 /*	$NetBSD: mesg.c,v 1.5 1997/08/01 04:32:44 mikel Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  * (c) UNIX System Laboratories, Inc.
      7  * All or some portions of this file are derived from material licensed
      8  * to the University of California by American Telephone and Telegraph
      9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     10  * the permission of UNIX System Laboratories, Inc.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the University of
     23  *	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  */
     40 
     41 #include <sys/cdefs.h>
     42 
     43 #ifndef lint
     44 __COPYRIGHT("@(#) Copyright (c) 1987, 1993\n\
     45 	The Regents of the University of California.  All rights reserved.\n");
     46 #endif /* not lint */
     47 
     48 #ifndef lint
     49 #if 0
     50 static char sccsid[] = "@(#)mesg.c	8.2 (Berkeley) 1/21/94";
     51 #endif
     52 __RCSID("$NetBSD: mesg.c,v 1.5 1997/08/01 04:32:44 mikel Exp $");
     53 #endif /* not lint */
     54 
     55 #include <sys/types.h>
     56 #include <sys/stat.h>
     57 
     58 #include <err.h>
     59 #include <errno.h>
     60 #include <stdio.h>
     61 #include <stdlib.h>
     62 #include <string.h>
     63 #include <unistd.h>
     64 
     65 int	main __P((int, char **));
     66 
     67 int
     68 main(argc, argv)
     69 	int argc;
     70 	char *argv[];
     71 {
     72 	struct stat sb;
     73 	char *tty;
     74 	int ch;
     75 
     76 	while ((ch = getopt(argc, argv, "")) != -1)
     77 		switch (ch) {
     78 		case '?':
     79 		default:
     80 			goto usage;
     81 		}
     82 	argc -= optind;
     83 	argv += optind;
     84 
     85 	if ((tty = ttyname(STDERR_FILENO)) == NULL)
     86 		err(2, "ttyname");
     87 	if (stat(tty, &sb) < 0)
     88 		err(2, "%s", tty);
     89 
     90 	if (*argv == NULL) {
     91 		if (sb.st_mode & S_IWGRP) {
     92 			(void)fprintf(stderr, "is y\n");
     93 			exit(0);
     94 		}
     95 		(void)fprintf(stderr, "is n\n");
     96 		exit(1);
     97 	}
     98 
     99 	switch (*argv[0]) {
    100 	case 'y':
    101 		if (chmod(tty, sb.st_mode | S_IWGRP) < 0)
    102 			err(2, "%s", tty);
    103 		exit(0);
    104 	case 'n':
    105 		if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0)
    106 			err(2, "%s", tty);
    107 		exit(1);
    108 	}
    109 
    110 usage:	(void)fprintf(stderr, "usage: mesg [y | n]\n");
    111 	exit(2);
    112 }
    113