1 /* $OpenBSD: mesg.c,v 1.7 2007/03/15 22:59:02 jmc Exp $ */ 2 /* $NetBSD: mesg.c,v 1.4 1994/12/23 07:16:32 jtc Exp $ */ 3 4 /* 5 * Copyright (c) 1987, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 38 #ifndef lint 39 static char copyright[] = 40 "@(#) Copyright (c) 1987, 1993\n\ 41 The Regents of the University of California. All rights reserved.\n"; 42 #endif /* not lint */ 43 44 #ifndef lint 45 #if 0 46 static char sccsid[] = "@(#)mesg.c 8.2 (Berkeley) 1/21/94"; 47 #endif 48 static char rcsid[] = "$OpenBSD: mesg.c,v 1.7 2007/03/15 22:59:02 jmc Exp $"; 49 #endif /* not lint */ 50 51 #include <sys/types.h> 52 #include <sys/stat.h> 53 54 #include <err.h> 55 #include <errno.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 61 int 62 main(int argc, char *argv[]) 63 { 64 struct stat sb; 65 char *tty; 66 int ch; 67 68 while ((ch = getopt(argc, argv, "")) != -1) 69 switch (ch) { 70 case '?': 71 default: 72 goto usage; 73 } 74 argc -= optind; 75 argv += optind; 76 77 if ((tty = ttyname(STDERR_FILENO)) == NULL) 78 err(2, "ttyname"); 79 if (stat(tty, &sb) < 0) 80 err(2, "%s", tty); 81 82 if (*argv == NULL) { 83 if (sb.st_mode & S_IWGRP) { 84 (void)fprintf(stderr, "is y\n"); 85 exit(0); 86 } 87 (void)fprintf(stderr, "is n\n"); 88 exit(1); 89 } 90 91 switch (*argv[0]) { 92 case 'y': 93 if (chmod(tty, sb.st_mode | S_IWGRP) < 0) 94 err(2, "%s", tty); 95 exit(0); 96 case 'n': 97 if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0) 98 err(2, "%s", tty); 99 exit(1); 100 } 101 102 usage: (void)fprintf(stderr, "usage: mesg [n | y]\n"); 103 exit(2); 104 } 105