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