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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef lint 40 static char copyright[] = 41 "@(#) Copyright (c) 1987, 1993\n\ 42 The Regents of the University of California. All rights reserved.\n"; 43 #endif /* not lint */ 44 45 #ifndef lint 46 static char sccsid[] = "@(#)mesg.c 8.2 (Berkeley) 1/21/94"; 47 #endif /* not lint */ 48 49 #include <sys/types.h> 50 #include <sys/stat.h> 51 52 #include <err.h> 53 #include <errno.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 #include <unistd.h> 58 59 int 60 main(argc, argv) 61 int argc; 62 char *argv[]; 63 { 64 struct stat sb; 65 char *tty; 66 int ch; 67 68 while ((ch = getopt(argc, argv, "")) != EOF) 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(1, "ttyname"); 79 if (stat(tty, &sb) < 0) 80 err(1, "%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(1, "%s", tty); 95 exit(0); 96 case 'n': 97 if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0) 98 err(1, "%s", tty); 99 exit(1); 100 } 101 102 usage: (void)fprintf(stderr, "usage: mesg [y | n]\n"); 103 exit(2); 104 } 105