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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved	*/
29 
30 #include "libmail.h"
31 #include <sys/types.h>
32 #include <sys/stat.h>
33 #include <fcntl.h>
34 #include <utmpx.h>
35 #include <syslog.h>
36 #if !defined(__cplusplus) && !defined(c_plusplus)
37 typedef void (*SIG_PF) (int);
38 #endif
39 #include <unistd.h>
40 #include <signal.h>
41 
42 static void
43 catcher(int arg __unused)
44 {
45 	/* do nothing, but allow the write() to break */
46 }
47 
48 void
49 notify(char *user, char *msg, int check_mesg_y, char *etcdir)
50 {
51 	/* search the utmp file for this user */
52 	SIG_PF old;
53 	unsigned int oldalarm;
54 	struct utmpx utmpx, *putmpx = &utmpx;
55 
56 	setutxent();
57 
58 	/* grab the tty name */
59 	while ((putmpx = getutxent()) != NULL) {
60 		if (strncmp(user, utmpx.ut_name,
61 		    sizeof (utmpx.ut_name)) == 0) {
62 			char tty[sizeof (utmpx.ut_line)+1];
63 			char dev[MAXFILENAME];
64 			FILE *port;
65 			size_t i;
66 			int fd;
67 
68 			for (i = 0; i < sizeof (utmpx.ut_line); i++)
69 				tty[i] = utmpx.ut_line[i];
70 			tty[i] = '\0';
71 
72 			/* stick /dev/ in front */
73 			(void) sprintf(dev, "%s/dev/%s", etcdir, tty);
74 
75 			/* break out if write() to the tty hangs */
76 			old = (SIG_PF)signal(SIGALRM, catcher);
77 			oldalarm = alarm(300);
78 
79 			/* check if device is really a tty */
80 			if ((fd = open(dev, O_WRONLY|O_NOCTTY)) == -1) {
81 				(void) fprintf(stderr,
82 				    "Cannot open %s.\n", dev);
83 				continue;
84 			} else {
85 				if (!isatty(fd)) {
86 					(void) fprintf(stderr, "%s in utmpx is "
87 					    "not a tty\n", tty);
88 					openlog("mail", 0, LOG_AUTH);
89 					syslog(LOG_CRIT, "%s in utmp is "
90 					    "not a tty\n", tty);
91 					closelog();
92 					(void) close(fd);
93 					continue;
94 				}
95 			}
96 			(void) close(fd);
97 
98 			/* write to the tty */
99 			port = fopen(dev, "w");
100 			if (port != 0) {
101 				(void) fprintf(port, "\r\n%s\r\n", msg);
102 				(void) fclose(port);
103 			}
104 
105 			/* clean up our alarm */
106 			(void) alarm(0);
107 			(void) signal(SIGALRM, old);
108 			(void) alarm(oldalarm);
109 		}
110 	}
111 	endutxent();
112 }
113