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 35 #ifndef lint 36 static const char copyright[] = 37 "@(#) Copyright (c) 1987, 1993\n\ 38 The Regents of the University of California. All rights reserved.\n"; 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)mesg.c 8.2 (Berkeley) 1/21/94"; 44 #endif 45 #endif /* not lint */ 46 #include <sys/cdefs.h> 47 __FBSDID("$FreeBSD$"); 48 49 #include <sys/types.h> 50 #include <sys/stat.h> 51 52 #include <err.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 static void usage(void); 59 60 int 61 main(int argc, char *argv[]) 62 { 63 struct stat sb; 64 char *tty; 65 int ch; 66 67 while ((ch = getopt(argc, argv, "")) != -1) 68 switch (ch) { 69 case '?': 70 default: 71 usage(); 72 } 73 argc -= optind; 74 argv += optind; 75 76 if ((tty = ttyname(STDIN_FILENO)) == NULL && 77 (tty = ttyname(STDOUT_FILENO)) == NULL && 78 (tty = ttyname(STDERR_FILENO)) == NULL) 79 err(2, "ttyname"); 80 if (stat(tty, &sb) < 0) 81 err(2, "%s", tty); 82 83 if (*argv == NULL) { 84 if (sb.st_mode & S_IWGRP) { 85 (void)puts("is y"); 86 exit(0); 87 } 88 (void)puts("is n"); 89 exit(1); 90 } 91 92 switch (*argv[0]) { 93 case 'y': 94 if (chmod(tty, sb.st_mode | S_IWGRP) < 0) 95 err(2, "%s", tty); 96 exit(0); 97 case 'n': 98 if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0) 99 err(2, "%s", tty); 100 exit(1); 101 } 102 103 usage(); 104 return(0); 105 } 106 107 static void 108 usage(void) 109 { 110 (void)fprintf(stderr, "usage: mesg [n | y]\n"); 111 exit(2); 112 } 113