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1 | /* |
2 | * Copyright (c) 1987 Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
f15db449 | 5 | * %sccs.include.redist.c% |
56b5a10f KB |
6 | */ |
7 | ||
8 | #ifndef lint | |
9 | char copyright[] = | |
10 | "@(#) Copyright (c) 1987 Regents of the University of California.\n\ | |
11 | All rights reserved.\n"; | |
12 | #endif /* not lint */ | |
13 | ||
14 | #ifndef lint | |
f15db449 | 15 | static char sccsid[] = "@(#)mesg.c 4.6 (Berkeley) %G%"; |
56b5a10f KB |
16 | #endif /* not lint */ |
17 | ||
69d8f2f4 BJ |
18 | /* |
19 | * mesg -- set current tty to accept or | |
20 | * forbid write permission. | |
21 | * | |
22 | * mesg [y] [n] | |
23 | * y allow messages | |
24 | * n forbid messages | |
25 | */ | |
26 | ||
69d8f2f4 BJ |
27 | #include <sys/types.h> |
28 | #include <sys/stat.h> | |
56b5a10f | 29 | #include <stdio.h> |
69d8f2f4 | 30 | |
56b5a10f | 31 | static char *tty; |
69d8f2f4 BJ |
32 | |
33 | main(argc, argv) | |
56b5a10f KB |
34 | int argc; |
35 | char **argv; | |
69d8f2f4 | 36 | { |
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37 | struct stat sbuf; |
38 | char *ttyname(); | |
69d8f2f4 | 39 | |
56b5a10f KB |
40 | if (!(tty = ttyname(2))) { |
41 | fputs("mesg: not a device in /dev.\n", stderr); | |
42 | exit(-1); | |
43 | } | |
44 | if (stat(tty, &sbuf) < 0) { | |
45 | perror("mesg"); | |
46 | exit(-1); | |
47 | } | |
48 | if (argc < 2) { | |
49 | if (sbuf.st_mode & 020) { | |
50 | fputs("is y\n", stderr); | |
51 | exit(0); | |
69d8f2f4 | 52 | } |
56b5a10f KB |
53 | fputs("is n\n", stderr); |
54 | exit(1); | |
55 | } | |
56 | #define OTHER_WRITE 020 | |
57 | switch(*argv[1]) { | |
58 | case 'y': | |
59 | newmode(sbuf.st_mode | OTHER_WRITE); | |
60 | exit(0); | |
61 | case 'n': | |
62 | newmode(sbuf.st_mode &~ OTHER_WRITE); | |
63 | exit(1); | |
64 | default: | |
65 | fputs("usage: mesg [y] [n]\n", stderr); | |
66 | exit(-1); | |
67 | } | |
68 | /*NOTREACHED*/ | |
69d8f2f4 BJ |
69 | } |
70 | ||
56b5a10f | 71 | static |
69d8f2f4 | 72 | newmode(m) |
56b5a10f | 73 | u_short m; |
69d8f2f4 | 74 | { |
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75 | if (chmod(tty, m) < 0) { |
76 | perror("mesg"); | |
77 | exit(-1); | |
78 | } | |
69d8f2f4 | 79 | } |