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 const 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 #if 0 47 static char sccsid[] = "@(#)mesg.c 8.2 (Berkeley) 1/21/94"; 48 #endif 49 static const char rcsid[] = 50 "$FreeBSD$"; 51 #endif /* not lint */ 52 53 #include <sys/types.h> 54 #include <sys/stat.h> 55 56 #include <err.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <unistd.h> 61 62 static void usage(void); 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, "")) != -1) 74 switch (ch) { 75 case '?': 76 default: 77 usage(); 78 } 79 argc -= optind; 80 argv += optind; 81 82 if ((tty = ttyname(STDIN_FILENO)) == NULL && 83 (tty = ttyname(STDOUT_FILENO)) == NULL && 84 (tty = ttyname(STDERR_FILENO)) == NULL) 85 err(2, "ttyname"); 86 if (stat(tty, &sb) < 0) 87 err(2, "%s", tty); 88 89 if (*argv == NULL) { 90 if (sb.st_mode & S_IWGRP) { 91 (void)puts("is y"); 92 exit(0); 93 } 94 (void)puts("is n"); 95 exit(1); 96 } 97 98 switch (*argv[0]) { 99 case 'y': 100 if (chmod(tty, sb.st_mode | S_IWGRP) < 0) 101 err(2, "%s", tty); 102 exit(0); 103 case 'n': 104 if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0) 105 err(2, "%s", tty); 106 exit(1); 107 } 108 109 usage(); 110 return(0); 111 } 112 113 static void 114 usage() 115 { 116 (void)fprintf(stderr, "usage: mesg [y | n]\n"); 117 exit(2); 118 } 119