xref: /illumos-gate/usr/src/cmd/mesg/mesg.c (revision 7c478bd9)
1*7c478bd9Sstevel@tonic-gate /*
2*7c478bd9Sstevel@tonic-gate  * CDDL HEADER START
3*7c478bd9Sstevel@tonic-gate  *
4*7c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*7c478bd9Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*7c478bd9Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*7c478bd9Sstevel@tonic-gate  * with the License.
8*7c478bd9Sstevel@tonic-gate  *
9*7c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*7c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*7c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*7c478bd9Sstevel@tonic-gate  * and limitations under the License.
13*7c478bd9Sstevel@tonic-gate  *
14*7c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*7c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*7c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*7c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*7c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*7c478bd9Sstevel@tonic-gate  *
20*7c478bd9Sstevel@tonic-gate  * CDDL HEADER END
21*7c478bd9Sstevel@tonic-gate  */
22*7c478bd9Sstevel@tonic-gate /*
23*7c478bd9Sstevel@tonic-gate  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
24*7c478bd9Sstevel@tonic-gate  * Use is subject to license terms.
25*7c478bd9Sstevel@tonic-gate  */
26*7c478bd9Sstevel@tonic-gate 
27*7c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*7c478bd9Sstevel@tonic-gate 
29*7c478bd9Sstevel@tonic-gate /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
30*7c478bd9Sstevel@tonic-gate /*	  All Rights Reserved  	*/
31*7c478bd9Sstevel@tonic-gate 
32*7c478bd9Sstevel@tonic-gate 
33*7c478bd9Sstevel@tonic-gate /*
34*7c478bd9Sstevel@tonic-gate  * mesg -- set current tty to accept or
35*7c478bd9Sstevel@tonic-gate  *	forbid write permission.
36*7c478bd9Sstevel@tonic-gate  *
37*7c478bd9Sstevel@tonic-gate  *	mesg [-y | -n | y | n]
38*7c478bd9Sstevel@tonic-gate  *		y allow messages
39*7c478bd9Sstevel@tonic-gate  *		n forbid messages
40*7c478bd9Sstevel@tonic-gate  *	return codes
41*7c478bd9Sstevel@tonic-gate  *		0 if messages are ON or turned ON
42*7c478bd9Sstevel@tonic-gate  *		1 if messages are OFF or turned OFF
43*7c478bd9Sstevel@tonic-gate  *		2 if an error occurs
44*7c478bd9Sstevel@tonic-gate  */
45*7c478bd9Sstevel@tonic-gate 
46*7c478bd9Sstevel@tonic-gate #include <stdio.h>
47*7c478bd9Sstevel@tonic-gate #include <stdlib.h>
48*7c478bd9Sstevel@tonic-gate #include <unistd.h>
49*7c478bd9Sstevel@tonic-gate #include <locale.h>
50*7c478bd9Sstevel@tonic-gate #include <libintl.h>
51*7c478bd9Sstevel@tonic-gate #include <sys/types.h>
52*7c478bd9Sstevel@tonic-gate #include <sys/stat.h>
53*7c478bd9Sstevel@tonic-gate 
54*7c478bd9Sstevel@tonic-gate static void error(const char *s);
55*7c478bd9Sstevel@tonic-gate static void newmode(mode_t m);
56*7c478bd9Sstevel@tonic-gate static void usage(void);
57*7c478bd9Sstevel@tonic-gate 
58*7c478bd9Sstevel@tonic-gate static char *tty;
59*7c478bd9Sstevel@tonic-gate 
60*7c478bd9Sstevel@tonic-gate int
main(int argc,char * argv[])61*7c478bd9Sstevel@tonic-gate main(int argc, char *argv[])
62*7c478bd9Sstevel@tonic-gate {
63*7c478bd9Sstevel@tonic-gate 	int i, c, r = 0;
64*7c478bd9Sstevel@tonic-gate 	int action = 0;
65*7c478bd9Sstevel@tonic-gate 	struct stat sbuf;
66*7c478bd9Sstevel@tonic-gate 
67*7c478bd9Sstevel@tonic-gate 	extern int optind;
68*7c478bd9Sstevel@tonic-gate 
69*7c478bd9Sstevel@tonic-gate 	(void) setlocale(LC_ALL, "");
70*7c478bd9Sstevel@tonic-gate #if !defined(TEXT_DOMAIN)		/* Should be defined by cc -D */
71*7c478bd9Sstevel@tonic-gate #define	TEXT_DOMAIN	"SYS_TEST"	/* Use this only if it weren't */
72*7c478bd9Sstevel@tonic-gate #endif
73*7c478bd9Sstevel@tonic-gate 	(void) textdomain(TEXT_DOMAIN);
74*7c478bd9Sstevel@tonic-gate 
75*7c478bd9Sstevel@tonic-gate 	/*
76*7c478bd9Sstevel@tonic-gate 	 * Check stdin, stdout and stderr, in order, for a tty
77*7c478bd9Sstevel@tonic-gate 	 */
78*7c478bd9Sstevel@tonic-gate 	for (i = 0; i <= 2; i++) {
79*7c478bd9Sstevel@tonic-gate 		if ((tty = ttyname(i)) != NULL)
80*7c478bd9Sstevel@tonic-gate 			break;
81*7c478bd9Sstevel@tonic-gate 	}
82*7c478bd9Sstevel@tonic-gate 
83*7c478bd9Sstevel@tonic-gate 	if (stat(tty, &sbuf) < 0)
84*7c478bd9Sstevel@tonic-gate 		error("cannot stat");
85*7c478bd9Sstevel@tonic-gate 
86*7c478bd9Sstevel@tonic-gate 	if (argc < 2) {
87*7c478bd9Sstevel@tonic-gate 		if (sbuf.st_mode & (S_IWGRP | S_IWOTH)) {
88*7c478bd9Sstevel@tonic-gate 			(void) printf("is y\n");
89*7c478bd9Sstevel@tonic-gate 		} else {
90*7c478bd9Sstevel@tonic-gate 			r = 1;
91*7c478bd9Sstevel@tonic-gate 			(void) printf("is n\n");
92*7c478bd9Sstevel@tonic-gate 		}
93*7c478bd9Sstevel@tonic-gate 		exit(r);
94*7c478bd9Sstevel@tonic-gate 	}
95*7c478bd9Sstevel@tonic-gate 
96*7c478bd9Sstevel@tonic-gate 	while ((c = getopt(argc, argv, "yn")) != EOF) {
97*7c478bd9Sstevel@tonic-gate 		switch (c) {
98*7c478bd9Sstevel@tonic-gate 		case 'y':
99*7c478bd9Sstevel@tonic-gate 			if (action > 0)
100*7c478bd9Sstevel@tonic-gate 				usage();
101*7c478bd9Sstevel@tonic-gate 
102*7c478bd9Sstevel@tonic-gate 			newmode(S_IRUSR | S_IWUSR | S_IWGRP);
103*7c478bd9Sstevel@tonic-gate 			action++;
104*7c478bd9Sstevel@tonic-gate 			break;
105*7c478bd9Sstevel@tonic-gate 
106*7c478bd9Sstevel@tonic-gate 		case 'n':
107*7c478bd9Sstevel@tonic-gate 			if (action > 0)
108*7c478bd9Sstevel@tonic-gate 				usage();
109*7c478bd9Sstevel@tonic-gate 
110*7c478bd9Sstevel@tonic-gate 			newmode(S_IRUSR | S_IWUSR);
111*7c478bd9Sstevel@tonic-gate 			r = 1;
112*7c478bd9Sstevel@tonic-gate 			action++;
113*7c478bd9Sstevel@tonic-gate 			break;
114*7c478bd9Sstevel@tonic-gate 
115*7c478bd9Sstevel@tonic-gate 		case '?':
116*7c478bd9Sstevel@tonic-gate 			usage();
117*7c478bd9Sstevel@tonic-gate 			break;
118*7c478bd9Sstevel@tonic-gate 		}
119*7c478bd9Sstevel@tonic-gate 	}
120*7c478bd9Sstevel@tonic-gate 
121*7c478bd9Sstevel@tonic-gate 	/*
122*7c478bd9Sstevel@tonic-gate 	 * Required for POSIX.2
123*7c478bd9Sstevel@tonic-gate 	 */
124*7c478bd9Sstevel@tonic-gate 	if (argc > optind) {
125*7c478bd9Sstevel@tonic-gate 		if (action > 0)
126*7c478bd9Sstevel@tonic-gate 			usage();
127*7c478bd9Sstevel@tonic-gate 
128*7c478bd9Sstevel@tonic-gate 		switch (*argv[optind]) {
129*7c478bd9Sstevel@tonic-gate 		case 'y':
130*7c478bd9Sstevel@tonic-gate 			newmode(S_IRUSR | S_IWUSR | S_IWGRP);
131*7c478bd9Sstevel@tonic-gate 			break;
132*7c478bd9Sstevel@tonic-gate 
133*7c478bd9Sstevel@tonic-gate 		case 'n':
134*7c478bd9Sstevel@tonic-gate 			newmode(S_IRUSR | S_IWUSR);
135*7c478bd9Sstevel@tonic-gate 			r = 1;
136*7c478bd9Sstevel@tonic-gate 			break;
137*7c478bd9Sstevel@tonic-gate 
138*7c478bd9Sstevel@tonic-gate 		default:
139*7c478bd9Sstevel@tonic-gate 			usage();
140*7c478bd9Sstevel@tonic-gate 			break;
141*7c478bd9Sstevel@tonic-gate 		}
142*7c478bd9Sstevel@tonic-gate 	}
143*7c478bd9Sstevel@tonic-gate 
144*7c478bd9Sstevel@tonic-gate 	return (r);
145*7c478bd9Sstevel@tonic-gate }
146*7c478bd9Sstevel@tonic-gate 
147*7c478bd9Sstevel@tonic-gate void
error(const char * s)148*7c478bd9Sstevel@tonic-gate error(const char *s)
149*7c478bd9Sstevel@tonic-gate {
150*7c478bd9Sstevel@tonic-gate 	(void) fprintf(stderr, "mesg: ");
151*7c478bd9Sstevel@tonic-gate 	(void) fprintf(stderr, "%s\n", s);
152*7c478bd9Sstevel@tonic-gate 	exit(2);
153*7c478bd9Sstevel@tonic-gate }
154*7c478bd9Sstevel@tonic-gate 
155*7c478bd9Sstevel@tonic-gate void
newmode(mode_t m)156*7c478bd9Sstevel@tonic-gate newmode(mode_t m)
157*7c478bd9Sstevel@tonic-gate {
158*7c478bd9Sstevel@tonic-gate 	if (chmod(tty, m) < 0)
159*7c478bd9Sstevel@tonic-gate 		error("cannot change mode");
160*7c478bd9Sstevel@tonic-gate }
161*7c478bd9Sstevel@tonic-gate 
162*7c478bd9Sstevel@tonic-gate void
usage(void)163*7c478bd9Sstevel@tonic-gate usage(void)
164*7c478bd9Sstevel@tonic-gate {
165*7c478bd9Sstevel@tonic-gate 	(void) fprintf(stderr, gettext("usage: mesg [-y | -n | y | n]\n"));
166*7c478bd9Sstevel@tonic-gate 	exit(2);
167*7c478bd9Sstevel@tonic-gate }
168