xref: /openbsd/libexec/ftpd/logutmp.c (revision d89ec533)
1 /*	$OpenBSD: logutmp.c,v 1.14 2019/06/28 13:32:53 deraadt Exp $	*/
2 /*
3  * Portions Copyright (c) 1988, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  * Portions Copyright (c) 1996, Jason Downs.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/types.h>
33 #include <sys/time.h>
34 #include <sys/socket.h>
35 #include <netinet/in.h>
36 #include <netinet/ip.h>
37 #include <netinet/tcp.h>
38 
39 #include <fcntl.h>
40 #include <unistd.h>
41 #include <stdlib.h>
42 #include <utmp.h>
43 #include <stdio.h>
44 #include <string.h>
45 #include <ttyent.h>
46 
47 #include "monitor.h"
48 #include "extern.h"
49 
50 static int fd = -1;
51 static int topslot = -1;
52 
53 /*
54  * Special versions of login()/logout() which hold the utmp file open,
55  * for use with ftpd.
56  */
57 
58 void
59 ftpd_login(struct utmp *ut)
60 {
61 	struct utmp ubuf;
62 
63 	/*
64 	 * First, loop through /etc/ttys, if needed, to initialize the
65 	 * top of the tty slots, since ftpd has no tty.
66 	 */
67 	if (topslot < 0) {
68 		topslot = 0;
69 		while (getttyent() != (struct ttyent *)NULL)
70 			topslot++;
71 	}
72 	if ((topslot < 0) || ((fd < 0) &&
73 	    (fd = open(_PATH_UTMP, O_RDWR|O_CREAT, 0644)) == -1))
74 		return;
75 
76 	/*
77 	 * Now find a slot that's not in use...
78 	 */
79 	(void)lseek(fd, (off_t)topslot * sizeof(struct utmp), SEEK_SET);
80 
81 	while (1) {
82 		if (read(fd, &ubuf, sizeof(struct utmp)) ==
83 		    sizeof(struct utmp)) {
84 			if (!ubuf.ut_name[0]) {
85 				(void)lseek(fd, -(off_t)sizeof(struct utmp),
86 				    SEEK_CUR);
87 				break;
88 			}
89 			topslot++;
90 		} else {
91 			(void)lseek(fd, (off_t)topslot * sizeof(struct utmp),
92 			    SEEK_SET);
93 			break;
94 		}
95 	}
96 
97 	(void)write(fd, ut, sizeof(struct utmp));
98 }
99 
100 int
101 ftpd_logout(char *line)
102 {
103 	struct timeval tv;
104 	struct utmp ut;
105 	int rval;
106 
107 	rval = 0;
108 	if (fd < 0)
109 		return(rval);
110 
111 	(void)lseek(fd, 0, SEEK_SET);
112 
113 	while (read(fd, &ut, sizeof(struct utmp)) == sizeof(struct utmp)) {
114 		if (!ut.ut_name[0] ||
115 		    strncmp(ut.ut_line, line, UT_LINESIZE))
116 			continue;
117 		bzero(ut.ut_name, UT_NAMESIZE);
118 		bzero(ut.ut_host, UT_HOSTSIZE);
119 		gettimeofday(&tv, NULL);
120 		ut.ut_time = tv.tv_sec;
121 		(void)lseek(fd, -(off_t)sizeof(struct utmp), SEEK_CUR);
122 		(void)write(fd, &ut, sizeof(struct utmp));
123 		rval = 1;
124 	}
125 	return(rval);
126 }
127