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169d8a33 RG |
1 | /* |
2 | * Copyright (c) UNIX System Laboratories, Inc. All or some portions | |
3 | * of this file are derived from material licensed to the | |
4 | * University of California by American Telephone and Telegraph Co. | |
5 | * or UNIX System Laboratories, Inc. and are reproduced herein with | |
6 | * the permission of UNIX System Laboratories, Inc. | |
7 | * | |
8 | * $Id$ | |
9 | */ | |
15637ed4 RG |
10 | /* |
11 | * Copyright (c) 1987 Regents of the University of California. | |
12 | * All rights reserved. | |
13 | * | |
14 | * Redistribution and use in source and binary forms, with or without | |
15 | * modification, are permitted provided that the following conditions | |
16 | * are met: | |
17 | * 1. Redistributions of source code must retain the above copyright | |
18 | * notice, this list of conditions and the following disclaimer. | |
19 | * 2. Redistributions in binary form must reproduce the above copyright | |
20 | * notice, this list of conditions and the following disclaimer in the | |
21 | * documentation and/or other materials provided with the distribution. | |
22 | * 3. All advertising materials mentioning features or use of this software | |
23 | * must display the following acknowledgement: | |
24 | * This product includes software developed by the University of | |
25 | * California, Berkeley and its contributors. | |
26 | * 4. Neither the name of the University nor the names of its contributors | |
27 | * may be used to endorse or promote products derived from this software | |
28 | * without specific prior written permission. | |
29 | * | |
30 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
31 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
32 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
33 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
34 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
35 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
36 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
37 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
38 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
39 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
40 | * SUCH DAMAGE. | |
41 | */ | |
42 | ||
43 | #ifndef lint | |
44 | char copyright[] = | |
45 | "@(#) Copyright (c) 1987 Regents of the University of California.\n\ | |
46 | All rights reserved.\n"; | |
47 | #endif /* not lint */ | |
48 | ||
49 | #ifndef lint | |
50 | static char sccsid[] = "@(#)mesg.c 4.7 (Berkeley) 3/1/91"; | |
51 | #endif /* not lint */ | |
52 | ||
53 | /* | |
54 | * mesg -- set current tty to accept or | |
55 | * forbid write permission. | |
56 | * | |
57 | * mesg [y] [n] | |
58 | * y allow messages | |
59 | * n forbid messages | |
60 | */ | |
61 | ||
62 | #include <sys/types.h> | |
63 | #include <sys/stat.h> | |
64 | #include <stdio.h> | |
65 | ||
66 | static char *tty; | |
bf054078 | 67 | #define OTHER_WRITE 020 |
15637ed4 RG |
68 | |
69 | main(argc, argv) | |
70 | int argc; | |
71 | char **argv; | |
72 | { | |
73 | struct stat sbuf; | |
74 | char *ttyname(); | |
75 | ||
76 | if (!(tty = ttyname(2))) { | |
77 | fputs("mesg: not a device in /dev.\n", stderr); | |
78 | exit(-1); | |
79 | } | |
80 | if (stat(tty, &sbuf) < 0) { | |
81 | perror("mesg"); | |
82 | exit(-1); | |
83 | } | |
84 | if (argc < 2) { | |
1a6bc87e | 85 | if (sbuf.st_mode & OTHER_WRITE) { |
15637ed4 RG |
86 | fputs("is y\n", stderr); |
87 | exit(0); | |
88 | } | |
89 | fputs("is n\n", stderr); | |
90 | exit(1); | |
91 | } | |
15637ed4 RG |
92 | switch(*argv[1]) { |
93 | case 'y': | |
94 | newmode(sbuf.st_mode | OTHER_WRITE); | |
95 | exit(0); | |
96 | case 'n': | |
97 | newmode(sbuf.st_mode &~ OTHER_WRITE); | |
98 | exit(1); | |
99 | default: | |
1a6bc87e | 100 | fputs("usage: mesg [y|n]\n", stderr); |
15637ed4 RG |
101 | exit(-1); |
102 | } | |
103 | /*NOTREACHED*/ | |
104 | } | |
105 | ||
106 | newmode(m) | |
107 | u_short m; | |
108 | { | |
109 | if (chmod(tty, m) < 0) { | |
110 | perror("mesg"); | |
111 | exit(-1); | |
112 | } | |
113 | } |