xref: /titanic_44/usr/src/cmd/mesg/mesg.c (revision 4eaa471005973e11a6110b69fe990530b3b95a38)
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
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
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
156  newmode(mode_t m)
157  {
158  	if (chmod(tty, m) < 0)
159  		error("cannot change mode");
160  }
161  
162  void
163  usage(void)
164  {
165  	(void) fprintf(stderr, gettext("usage: mesg [-y | -n | y | n]\n"));
166  	exit(2);
167  }
168