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disklabel_scan.c revision 1.2.8.2 
      1  1.2.8.2  martin /* $NetBSD: disklabel_scan.c,v 1.2.8.2 2008/04/28 20:23:03 martin Exp $ */
      2  1.2.8.2  martin 
      3  1.2.8.2  martin /*-
      4  1.2.8.2  martin  * Copyright (c) 2002 The NetBSD Foundation, Inc.
      5  1.2.8.2  martin  * All rights reserved.
      6  1.2.8.2  martin  *
      7  1.2.8.2  martin  * This code is derived from software contributed to The NetBSD Foundation
      8  1.2.8.2  martin  * by Roland C. Dowdeswell.
      9  1.2.8.2  martin  *
     10  1.2.8.2  martin  * Redistribution and use in source and binary forms, with or without
     11  1.2.8.2  martin  * modification, are permitted provided that the following conditions
     12  1.2.8.2  martin  * are met:
     13  1.2.8.2  martin  * 1. Redistributions of source code must retain the above copyright
     14  1.2.8.2  martin  *    notice, this list of conditions and the following disclaimer.
     15  1.2.8.2  martin  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2.8.2  martin  *    notice, this list of conditions and the following disclaimer in the
     17  1.2.8.2  martin  *    documentation and/or other materials provided with the distribution.
     18  1.2.8.2  martin  *
     19  1.2.8.2  martin  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.2.8.2  martin  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.2.8.2  martin  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.2.8.2  martin  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.2.8.2  martin  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.2.8.2  martin  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.2.8.2  martin  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.2.8.2  martin  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.2.8.2  martin  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.2.8.2  martin  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.2.8.2  martin  * POSSIBILITY OF SUCH DAMAGE.
     30  1.2.8.2  martin  */
     31  1.2.8.2  martin 
     32  1.2.8.2  martin #include <sys/cdefs.h>
     33  1.2.8.2  martin #ifndef lint
     34  1.2.8.2  martin __COPYRIGHT(
     35  1.2.8.2  martin "@(#) Copyright (c) 2002\
     36  1.2.8.2  martin 	The NetBSD Foundation, Inc.  All rights reserved.");
     37  1.2.8.2  martin __RCSID("$NetBSD: disklabel_scan.c,v 1.2.8.2 2008/04/28 20:23:03 martin Exp $");
     38  1.2.8.2  martin #endif
     39  1.2.8.2  martin 
     40  1.2.8.2  martin #include <string.h>
     41  1.2.8.2  martin #include <unistd.h>
     42  1.2.8.2  martin #include <util.h>
     43  1.2.8.2  martin 
     44  1.2.8.2  martin #include <sys/disklabel.h>
     45  1.2.8.2  martin 
     46  1.2.8.2  martin #define SCAN_INCR	4
     47  1.2.8.2  martin 
     48  1.2.8.2  martin int
     49  1.2.8.2  martin disklabel_scan(struct disklabel *lp, char *buf, size_t buflen)
     50  1.2.8.2  martin {
     51  1.2.8.2  martin 	int	i;
     52  1.2.8.2  martin 
     53  1.2.8.2  martin 	/* scan for the correct magic numbers. */
     54  1.2.8.2  martin 
     55  1.2.8.2  martin 	for (i=0; i <= buflen - sizeof(*lp); i += SCAN_INCR) {
     56  1.2.8.2  martin 		memcpy(lp, buf + i, sizeof(*lp));
     57  1.2.8.2  martin 		if (lp->d_magic == DISKMAGIC && lp->d_magic2 == DISKMAGIC)
     58  1.2.8.2  martin 			goto sanity;
     59  1.2.8.2  martin 	}
     60  1.2.8.2  martin 
     61  1.2.8.2  martin 	return 1;
     62  1.2.8.2  martin 
     63  1.2.8.2  martin sanity:
     64  1.2.8.2  martin 	/* we've found something, let's sanity check it */
     65  1.2.8.2  martin 	if (lp->d_npartitions > MAXPARTITIONS || disklabel_dkcksum(lp))
     66  1.2.8.2  martin 		return 1;
     67  1.2.8.2  martin 
     68  1.2.8.2  martin 	return 0;
     69  1.2.8.2  martin }
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