xref: /netbsd-src/lib/libc/gen/utmp.c (revision f04f8bc9492e77ca7da3c8a8cf08ce637a1a8f27)
1 /*	$NetBSD: utmp.c,v 1.3 2002/07/28 21:46:03 christos Exp $	 */
2 
3 /*-
4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Christos Zoulas.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 #include <sys/cdefs.h>
39 
40 #if defined(LIBC_SCCS) && !defined(lint)
41 __RCSID("$NetBSD: utmp.c,v 1.3 2002/07/28 21:46:03 christos Exp $");
42 #endif /* LIBC_SCCS and not lint */
43 
44 #include <sys/types.h>
45 #include <sys/param.h>
46 #include <stdio.h>
47 #include <time.h>
48 #include <utmp.h>
49 
50 static struct utmp utmp;
51 static FILE *ut;
52 static char utfile[MAXPATHLEN] = _PATH_UTMP;
53 
54 void
55 setutent(void)
56 {
57 	if (ut == NULL)
58 		return;
59 	(void)fseeko(ut, (off_t)0, SEEK_SET);
60 }
61 
62 struct utmp *
63 getutent(void)
64 {
65 	if (ut == NULL) {
66 		if ((ut = fopen(utfile, "r")) == NULL)
67 			return NULL;
68 	}
69 	if (fread(&utmp, sizeof(utmp), 1, ut) == 1)
70 		return &utmp;
71 	return NULL;
72 }
73 
74 void
75 endutent(void)
76 {
77 	if (ut != NULL) {
78 		(void)fclose(ut);
79 		ut = NULL;
80 	}
81 }
82 
83 int
84 utmpname(const char *fname)
85 {
86 	size_t len = strlen(fname);
87 
88 	if (len >= sizeof(utfile))
89 		return 0;
90 
91 	/* must not end in x! */
92 	if (fname[len - 1] == 'x')
93 		return 0;
94 
95 	(void)strcpy(utfile, fname);
96 	endutent();
97 	return 1;
98 }
99