1 /* 2 * Copyright (c) 1987, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#) Copyright (c) 1987, 1993 The Regents of the University of California. All rights reserved. 35 * @(#)mesg.c 8.2 (Berkeley) 1/21/94 36 * $FreeBSD: src/usr.bin/mesg/mesg.c,v 1.4 1999/08/28 01:03:59 peter Exp $ 37 * $DragonFly: src/usr.bin/mesg/mesg.c,v 1.5 2005/03/04 10:34:39 liamfoy Exp $ 38 */ 39 40 #include <sys/types.h> 41 #include <sys/stat.h> 42 43 #include <err.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <unistd.h> 47 48 static void usage(void); 49 50 int 51 main(int argc, char **argv) 52 { 53 struct stat sb; 54 char *tty; 55 int ch; 56 57 while ((ch = getopt(argc, argv, "")) != -1) 58 switch (ch) { 59 case '?': 60 default: 61 usage(); 62 } 63 argc -= optind; 64 argv += optind; 65 66 if ((tty = ttyname(STDIN_FILENO)) == NULL && 67 (tty = ttyname(STDOUT_FILENO)) == NULL && 68 (tty = ttyname(STDERR_FILENO)) == NULL) 69 err(2, "ttyname failed"); 70 if (stat(tty, &sb) < 0) 71 err(2, "%s", tty); 72 73 if (*argv == NULL) { 74 if (sb.st_mode & S_IWGRP) { 75 fprintf(stdout, "is y\n"); 76 exit(0); 77 } 78 fprintf(stdout, "is n\n"); 79 exit(1); 80 } 81 82 switch (*argv[0]) { 83 case 'y': 84 if (chmod(tty, sb.st_mode | S_IWGRP) < 0) 85 err(2, "%s", tty); 86 exit(0); 87 case 'n': 88 if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0) 89 err(2, "%s", tty); 90 exit(1); 91 } 92 93 usage(); 94 return(0); 95 } 96 97 static void 98 usage(void) 99 { 100 fprintf(stderr, "usage: mesg [y | n]\n"); 101 exit(2); 102 } 103