logutmp.c revision 1.7 
1/*	$OpenBSD: logutmp.c,v 1.7 2003/07/07 03:18:11 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/socket.h>
34#include <netinet/in.h>
35#include <netinet/in_systm.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#include "extern.h"
47
48static int fd = -1;
49static int topslot = -1;
50
51/*
52 * Special versions of login()/logout() which hold the utmp file open,
53 * for use with ftpd.
54 */
55
56void
57ftpd_login(struct utmp *ut)
58{
59	struct utmp ubuf;
60
61	/*
62	 * First, loop through /etc/ttys, if needed, to initialize the
63	 * top of the tty slots, since ftpd has no tty.
64	 */
65	if (topslot < 0) {
66		topslot = 0;
67		while (getttyent() != (struct ttyent *)NULL)
68			topslot++;
69	}
70	if ((topslot < 0) || ((fd < 0) &&
71	    (fd = open(_PATH_UTMP, O_RDWR|O_CREAT, 0644)) < 0))
72	    	return;
73
74	/*
75	 * Now find a slot that's not in use...
76	 */
77	(void)lseek(fd, (off_t)(topslot * sizeof(struct utmp)), SEEK_SET);
78
79	while (1) {
80		if (read(fd, &ubuf, sizeof(struct utmp)) ==
81		    sizeof(struct utmp)) {
82			if (!ubuf.ut_name[0]) {
83				(void)lseek(fd, -(off_t)sizeof(struct utmp),
84				    SEEK_CUR);
85				break;
86			}
87			topslot++;
88		} else {
89			(void)lseek(fd, (off_t)(topslot *
90			    sizeof(struct utmp)), SEEK_SET);
91			break;
92		}
93	}
94
95	(void)write(fd, ut, sizeof(struct utmp));
96}
97
98int
99ftpd_logout(char *line)
100{
101	struct utmp ut;
102	int rval;
103
104	rval = 0;
105	if (fd < 0)
106		return(rval);
107
108	(void)lseek(fd, 0, SEEK_SET);
109
110	while (read(fd, &ut, sizeof(struct utmp)) == sizeof(struct utmp)) {
111		if (!ut.ut_name[0] ||
112		    strncmp(ut.ut_line, line, UT_LINESIZE))
113			continue;
114		bzero(ut.ut_name, UT_NAMESIZE);
115		bzero(ut.ut_host, UT_HOSTSIZE);
116		(void)time(&ut.ut_time);
117		(void)lseek(fd, -(off_t)sizeof(struct utmp), SEEK_CUR);
118		(void)write(fd, &ut, sizeof(struct utmp));
119		rval = 1;
120	}
121	return(rval);
122}
123