xref: /minix3/lib/libutil/disklabel_scan.c (revision 0c3983b25a88161cf074524e5c94585a2582ae82)
1*0c3983b2SBen Gras /* $NetBSD: disklabel_scan.c,v 1.3 2009/01/18 12:13:03 lukem Exp $ */
2*0c3983b2SBen Gras 
3*0c3983b2SBen Gras /*-
4*0c3983b2SBen Gras  * Copyright (c) 2002 The NetBSD Foundation, Inc.
5*0c3983b2SBen Gras  * All rights reserved.
6*0c3983b2SBen Gras  *
7*0c3983b2SBen Gras  * This code is derived from software contributed to The NetBSD Foundation
8*0c3983b2SBen Gras  * by Roland C. Dowdeswell.
9*0c3983b2SBen Gras  *
10*0c3983b2SBen Gras  * Redistribution and use in source and binary forms, with or without
11*0c3983b2SBen Gras  * modification, are permitted provided that the following conditions
12*0c3983b2SBen Gras  * are met:
13*0c3983b2SBen Gras  * 1. Redistributions of source code must retain the above copyright
14*0c3983b2SBen Gras  *    notice, this list of conditions and the following disclaimer.
15*0c3983b2SBen Gras  * 2. Redistributions in binary form must reproduce the above copyright
16*0c3983b2SBen Gras  *    notice, this list of conditions and the following disclaimer in the
17*0c3983b2SBen Gras  *    documentation and/or other materials provided with the distribution.
18*0c3983b2SBen Gras  *
19*0c3983b2SBen Gras  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*0c3983b2SBen Gras  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*0c3983b2SBen Gras  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*0c3983b2SBen Gras  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*0c3983b2SBen Gras  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*0c3983b2SBen Gras  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*0c3983b2SBen Gras  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*0c3983b2SBen Gras  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*0c3983b2SBen Gras  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*0c3983b2SBen Gras  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*0c3983b2SBen Gras  * POSSIBILITY OF SUCH DAMAGE.
30*0c3983b2SBen Gras  */
31*0c3983b2SBen Gras 
32*0c3983b2SBen Gras #include <sys/cdefs.h>
33*0c3983b2SBen Gras #ifndef lint
34*0c3983b2SBen Gras __COPYRIGHT(
35*0c3983b2SBen Gras "@(#) Copyright (c) 2002\
36*0c3983b2SBen Gras 	The NetBSD Foundation, Inc.  All rights reserved.");
37*0c3983b2SBen Gras __RCSID("$NetBSD: disklabel_scan.c,v 1.3 2009/01/18 12:13:03 lukem Exp $");
38*0c3983b2SBen Gras #endif
39*0c3983b2SBen Gras 
40*0c3983b2SBen Gras #include <string.h>
41*0c3983b2SBen Gras #include <unistd.h>
42*0c3983b2SBen Gras #include <util.h>
43*0c3983b2SBen Gras 
44*0c3983b2SBen Gras #include <sys/disklabel.h>
45*0c3983b2SBen Gras 
46*0c3983b2SBen Gras #define SCAN_INCR	4
47*0c3983b2SBen Gras 
48*0c3983b2SBen Gras int
disklabel_scan(struct disklabel * lp,char * buf,size_t buflen)49*0c3983b2SBen Gras disklabel_scan(struct disklabel *lp, char *buf, size_t buflen)
50*0c3983b2SBen Gras {
51*0c3983b2SBen Gras 	size_t	i;
52*0c3983b2SBen Gras 
53*0c3983b2SBen Gras 	/* scan for the correct magic numbers. */
54*0c3983b2SBen Gras 
55*0c3983b2SBen Gras 	for (i=0; i <= buflen - sizeof(*lp); i += SCAN_INCR) {
56*0c3983b2SBen Gras 		memcpy(lp, buf + i, sizeof(*lp));
57*0c3983b2SBen Gras 		if (lp->d_magic == DISKMAGIC && lp->d_magic2 == DISKMAGIC)
58*0c3983b2SBen Gras 			goto sanity;
59*0c3983b2SBen Gras 	}
60*0c3983b2SBen Gras 
61*0c3983b2SBen Gras 	return 1;
62*0c3983b2SBen Gras 
63*0c3983b2SBen Gras sanity:
64*0c3983b2SBen Gras 	/* we've found something, let's sanity check it */
65*0c3983b2SBen Gras 	if (lp->d_npartitions > MAXPARTITIONS || disklabel_dkcksum(lp))
66*0c3983b2SBen Gras 		return 1;
67*0c3983b2SBen Gras 
68*0c3983b2SBen Gras 	return 0;
69*0c3983b2SBen Gras }
70