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mesg.c revision 1.4 
      1 /*	$NetBSD: mesg.c,v 1.4 1994/12/23 07:16:32 jtc 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 #ifndef lint
     42 static char copyright[] =
     43 "@(#) Copyright (c) 1987, 1993\n\
     44 	The Regents of the University of California.  All rights reserved.\n";
     45 #endif /* not lint */
     46 
     47 #ifndef lint
     48 #if 0
     49 static char sccsid[] = "@(#)mesg.c	8.2 (Berkeley) 1/21/94";
     50 #endif
     51 static char rcsid[] = "$NetBSD: mesg.c,v 1.4 1994/12/23 07:16:32 jtc Exp $";
     52 #endif /* not lint */
     53 
     54 #include <sys/types.h>
     55 #include <sys/stat.h>
     56 
     57 #include <err.h>
     58 #include <errno.h>
     59 #include <stdio.h>
     60 #include <stdlib.h>
     61 #include <string.h>
     62 #include <unistd.h>
     63 
     64 int
     65 main(argc, argv)
     66 	int argc;
     67 	char *argv[];
     68 {
     69 	struct stat sb;
     70 	char *tty;
     71 	int ch;
     72 
     73 	while ((ch = getopt(argc, argv, "")) != EOF)
     74 		switch (ch) {
     75 		case '?':
     76 		default:
     77 			goto usage;
     78 		}
     79 	argc -= optind;
     80 	argv += optind;
     81 
     82 	if ((tty = ttyname(STDERR_FILENO)) == NULL)
     83 		err(1, "ttyname");
     84 	if (stat(tty, &sb) < 0)
     85 		err(1, "%s", tty);
     86 
     87 	if (*argv == NULL) {
     88 		if (sb.st_mode & S_IWGRP) {
     89 			(void)fprintf(stderr, "is y\n");
     90 			exit(0);
     91 		}
     92 		(void)fprintf(stderr, "is n\n");
     93 		exit(1);
     94 	}
     95 
     96 	switch (*argv[0]) {
     97 	case 'y':
     98 		if (chmod(tty, sb.st_mode | S_IWGRP) < 0)
     99 			err(1, "%s", tty);
    100 		exit(0);
    101 	case 'n':
    102 		if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0)
    103 			err(1, "%s", tty);
    104 		exit(1);
    105 	}
    106 
    107 usage:	(void)fprintf(stderr, "usage: mesg [y | n]\n");
    108 	exit(2);
    109 }
    110