1 /* $OpenBSD: login.c,v 1.9 2004/05/28 07:03:47 deraadt Exp $ */
2 /*
3 * Copyright (c) 1988, 1993
4 * The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #if defined(LIBC_SCCS) && !defined(lint)
32 /* from: static char sccsid[] = "@(#)login.c 8.1 (Berkeley) 6/4/93"; */
33 static const char rcsid[] = "$Id: login.c,v 1.9 2004/05/28 07:03:47 deraadt Exp $";
34 #endif /* LIBC_SCCS and not lint */
35
36 #include <sys/types.h>
37
38 #include <fcntl.h>
39 #include <unistd.h>
40 #include <stdlib.h>
41 #include <utmp.h>
42 #include <stdio.h>
43 #include <string.h>
44
45 #include "util.h"
46
47 void
login(struct utmp * utp)48 login(struct utmp *utp)
49 {
50 struct utmp old_ut;
51 register int fd;
52 int tty;
53
54 tty = ttyslot();
55 if (tty > 0 && (fd = open(_PATH_UTMP, O_RDWR|O_CREAT, 0644)) >= 0) {
56 (void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);
57 /*
58 * Prevent luser from zero'ing out ut_host.
59 * If the new ut_line is empty but the old one is not
60 * and ut_line and ut_name match, preserve the old ut_line.
61 */
62 if (read(fd, &old_ut, sizeof(struct utmp)) ==
63 sizeof(struct utmp) && utp->ut_host[0] == '\0' &&
64 old_ut.ut_host[0] != '\0' &&
65 strncmp(old_ut.ut_line, utp->ut_line, UT_LINESIZE) == 0 &&
66 strncmp(old_ut.ut_name, utp->ut_name, UT_NAMESIZE) == 0)
67 (void)memcpy(utp->ut_host, old_ut.ut_host, UT_HOSTSIZE);
68 (void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);
69 (void)write(fd, utp, sizeof(struct utmp));
70 (void)close(fd);
71 }
72 if ((fd = open(_PATH_WTMP, O_WRONLY|O_APPEND, 0)) >= 0) {
73 (void)write(fd, utp, sizeof(struct utmp));
74 (void)close(fd);
75 }
76 }
77