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 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
30 /* All Rights Reserved */
31
32
33 /*
34 * mesg -- set current tty to accept or
35 * forbid write permission.
36 *
37 * mesg [-y | -n | y | n]
38 * y allow messages
39 * n forbid messages
40 * return codes
41 * 0 if messages are ON or turned ON
42 * 1 if messages are OFF or turned OFF
43 * 2 if an error occurs
44 */
45
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <unistd.h>
49 #include <locale.h>
50 #include <libintl.h>
51 #include <sys/types.h>
52 #include <sys/stat.h>
53
54 static void error(const char *s);
55 static void newmode(mode_t m);
56 static void usage(void);
57
58 static char *tty;
59
60 int
main(int argc,char * argv[])61 main(int argc, char *argv[])
62 {
63 int i, c, r = 0;
64 int action = 0;
65 struct stat sbuf;
66
67 extern int optind;
68
69 (void) setlocale(LC_ALL, "");
70 #if !defined(TEXT_DOMAIN) /* Should be defined by cc -D */
71 #define TEXT_DOMAIN "SYS_TEST" /* Use this only if it weren't */
72 #endif
73 (void) textdomain(TEXT_DOMAIN);
74
75 /*
76 * Check stdin, stdout and stderr, in order, for a tty
77 */
78 for (i = 0; i <= 2; i++) {
79 if ((tty = ttyname(i)) != NULL)
80 break;
81 }
82
83 if (stat(tty, &sbuf) < 0)
84 error("cannot stat");
85
86 if (argc < 2) {
87 if (sbuf.st_mode & (S_IWGRP | S_IWOTH)) {
88 (void) printf("is y\n");
89 } else {
90 r = 1;
91 (void) printf("is n\n");
92 }
93 exit(r);
94 }
95
96 while ((c = getopt(argc, argv, "yn")) != EOF) {
97 switch (c) {
98 case 'y':
99 if (action > 0)
100 usage();
101
102 newmode(S_IRUSR | S_IWUSR | S_IWGRP);
103 action++;
104 break;
105
106 case 'n':
107 if (action > 0)
108 usage();
109
110 newmode(S_IRUSR | S_IWUSR);
111 r = 1;
112 action++;
113 break;
114
115 case '?':
116 usage();
117 break;
118 }
119 }
120
121 /*
122 * Required for POSIX.2
123 */
124 if (argc > optind) {
125 if (action > 0)
126 usage();
127
128 switch (*argv[optind]) {
129 case 'y':
130 newmode(S_IRUSR | S_IWUSR | S_IWGRP);
131 break;
132
133 case 'n':
134 newmode(S_IRUSR | S_IWUSR);
135 r = 1;
136 break;
137
138 default:
139 usage();
140 break;
141 }
142 }
143
144 return (r);
145 }
146
147 void
error(const char * s)148 error(const char *s)
149 {
150 (void) fprintf(stderr, "mesg: ");
151 (void) fprintf(stderr, "%s\n", s);
152 exit(2);
153 }
154
155 void
newmode(mode_t m)156 newmode(mode_t m)
157 {
158 if (chmod(tty, m) < 0)
159 error("cannot change mode");
160 }
161
162 void
usage(void)163 usage(void)
164 {
165 (void) fprintf(stderr, gettext("usage: mesg [-y | -n | y | n]\n"));
166 exit(2);
167 }
168