1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30
31 /*
32 * mesg -- set current tty to accept or
33 * forbid write permission.
34 *
35 * mesg [-y | -n | y | n]
36 * y allow messages
37 * n forbid messages
38 * return codes
39 * 0 if messages are ON or turned ON
40 * 1 if messages are OFF or turned OFF
41 * 2 if an error occurs
42 */
43
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <unistd.h>
47 #include <locale.h>
48 #include <libintl.h>
49 #include <sys/types.h>
50 #include <sys/stat.h>
51
52 static void error(const char *s);
53 static void newmode(mode_t m);
54 static void usage(void);
55
56 static char *tty;
57
58 int
main(int argc,char * argv[])59 main(int argc, char *argv[])
60 {
61 int i, c, r = 0;
62 int action = 0;
63 struct stat sbuf;
64
65 extern int optind;
66
67 (void) setlocale(LC_ALL, "");
68 #if !defined(TEXT_DOMAIN) /* Should be defined by cc -D */
69 #define TEXT_DOMAIN "SYS_TEST" /* Use this only if it weren't */
70 #endif
71 (void) textdomain(TEXT_DOMAIN);
72
73 /*
74 * Check stdin, stdout and stderr, in order, for a tty
75 */
76 for (i = 0; i <= 2; i++) {
77 if ((tty = ttyname(i)) != NULL)
78 break;
79 }
80
81 if (stat(tty, &sbuf) < 0)
82 error("cannot stat");
83
84 if (argc < 2) {
85 if (sbuf.st_mode & (S_IWGRP | S_IWOTH)) {
86 (void) printf("is y\n");
87 } else {
88 r = 1;
89 (void) printf("is n\n");
90 }
91 exit(r);
92 }
93
94 while ((c = getopt(argc, argv, "yn")) != EOF) {
95 switch (c) {
96 case 'y':
97 if (action > 0)
98 usage();
99
100 newmode(S_IRUSR | S_IWUSR | S_IWGRP);
101 action++;
102 break;
103
104 case 'n':
105 if (action > 0)
106 usage();
107
108 newmode(S_IRUSR | S_IWUSR);
109 r = 1;
110 action++;
111 break;
112
113 case '?':
114 usage();
115 break;
116 }
117 }
118
119 /*
120 * Required for POSIX.2
121 */
122 if (argc > optind) {
123 if (action > 0)
124 usage();
125
126 switch (*argv[optind]) {
127 case 'y':
128 newmode(S_IRUSR | S_IWUSR | S_IWGRP);
129 break;
130
131 case 'n':
132 newmode(S_IRUSR | S_IWUSR);
133 r = 1;
134 break;
135
136 default:
137 usage();
138 break;
139 }
140 }
141
142 return (r);
143 }
144
145 void
error(const char * s)146 error(const char *s)
147 {
148 (void) fprintf(stderr, "mesg: ");
149 (void) fprintf(stderr, "%s\n", s);
150 exit(2);
151 }
152
153 void
newmode(mode_t m)154 newmode(mode_t m)
155 {
156 if (chmod(tty, m) < 0)
157 error("cannot change mode");
158 }
159
160 void
usage(void)161 usage(void)
162 {
163 (void) fprintf(stderr, gettext("usage: mesg [-y | -n | y | n]\n"));
164 exit(2);
165 }
166