xref: /netbsd/libexec/ftpd/logutmp.c (revision bf9ec67e)
1 /*
2  * Portions Copyright (c) 1988, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * Portions Copyright (c) 1996, Jason Downs.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by the University of
17  *	California, Berkeley and its contributors.
18  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/types.h>
36 
37 #include <fcntl.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <ttyent.h>
42 #include <unistd.h>
43 #include <utmp.h>
44 #include <util.h>
45 
46 typedef struct utmp UTMP;
47 
48 static int fd = -1;
49 static int topslot = -1;
50 
51 /*
52  * Special versions of login()/logout() which hold the utmp file open,
53  * for use with ftpd.
54  */
55 
56 void
57 login(const UTMP *ut)
58 {
59 	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(UTMP)), SEEK_SET);
78 
79 	while (1) {
80 		if (read(fd, &ubuf, sizeof(UTMP)) == sizeof(UTMP)) {
81 			if (!ubuf.ut_name[0]) {
82 				(void)lseek(fd, -(off_t)sizeof(UTMP), SEEK_CUR);
83 				break;
84 			}
85 			topslot++;
86 		} else {
87 			(void)lseek(fd, (off_t)(topslot * sizeof(UTMP)),
88 			    SEEK_SET);
89 			break;
90 		}
91 	}
92 
93 	(void)write(fd, ut, sizeof(UTMP));
94 }
95 
96 int
97 logout(const char *line)
98 {
99 	UTMP ut;
100 	int rval;
101 
102 	rval = 0;
103 	if (fd < 0)
104 		return(rval);
105 
106 	(void)lseek(fd, 0, SEEK_SET);
107 
108 	while (read(fd, &ut, sizeof(UTMP)) == sizeof(UTMP)) {
109 		if (!ut.ut_name[0]
110 		    || strncmp(ut.ut_line, line, UT_LINESIZE))
111 			continue;
112 		memset(ut.ut_name, 0, UT_NAMESIZE);
113 		memset(ut.ut_host, 0, UT_HOSTSIZE);
114 		(void)time(&ut.ut_time);
115 		(void)lseek(fd, -(off_t)sizeof(UTMP), SEEK_CUR);
116 		(void)write(fd, &ut, sizeof(UTMP));
117 		rval = 1;
118 	}
119 	return(rval);
120 }
121