| 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 | * %sccs.include.redist.c% |
| 11 | */ |
| 12 | |
| 13 | #ifndef lint |
| 14 | static char copyright[] = |
| 15 | "@(#) Copyright (c) 1987, 1993\n\ |
| 16 | The Regents of the University of California. All rights reserved.\n"; |
| 17 | #endif /* not lint */ |
| 18 | |
| 19 | #ifndef lint |
| 20 | static char sccsid[] = "@(#)mesg.c 8.2 (Berkeley) %G%"; |
| 21 | #endif /* not lint */ |
| 22 | |
| 23 | #include <sys/types.h> |
| 24 | #include <sys/stat.h> |
| 25 | |
| 26 | #include <err.h> |
| 27 | #include <errno.h> |
| 28 | #include <stdio.h> |
| 29 | #include <stdlib.h> |
| 30 | #include <string.h> |
| 31 | #include <unistd.h> |
| 32 | |
| 33 | int |
| 34 | main(argc, argv) |
| 35 | int argc; |
| 36 | char *argv[]; |
| 37 | { |
| 38 | struct stat sb; |
| 39 | char *tty; |
| 40 | int ch; |
| 41 | |
| 42 | while ((ch = getopt(argc, argv, "")) != EOF) |
| 43 | switch (ch) { |
| 44 | case '?': |
| 45 | default: |
| 46 | goto usage; |
| 47 | } |
| 48 | argc -= optind; |
| 49 | argv += optind; |
| 50 | |
| 51 | if ((tty = ttyname(STDERR_FILENO)) == NULL) |
| 52 | err(1, "ttyname"); |
| 53 | if (stat(tty, &sb) < 0) |
| 54 | err(1, "%s", tty); |
| 55 | |
| 56 | if (*argv == NULL) { |
| 57 | if (sb.st_mode & S_IWGRP) { |
| 58 | (void)fprintf(stderr, "is y\n"); |
| 59 | exit(0); |
| 60 | } |
| 61 | (void)fprintf(stderr, "is n\n"); |
| 62 | exit(1); |
| 63 | } |
| 64 | |
| 65 | switch (*argv[0]) { |
| 66 | case 'y': |
| 67 | if (chmod(tty, sb.st_mode | S_IWGRP) < 0) |
| 68 | err(1, "%s", tty); |
| 69 | exit(0); |
| 70 | case 'n': |
| 71 | if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0) |
| 72 | err(1, "%s", tty); |
| 73 | exit(1); |
| 74 | } |
| 75 | |
| 76 | usage: (void)fprintf(stderr, "usage: mesg [y | n]\n"); |
| 77 | exit(2); |
| 78 | } |