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      1 /* $NetBSD: disklabel_scan.c,v 1.3 2009/01/18 12:13:03 lukem 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 Roland C. Dowdeswell.
      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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 __COPYRIGHT(
     35 "@(#) Copyright (c) 2002\
     36 	The NetBSD Foundation, Inc.  All rights reserved.");
     37 __RCSID("$NetBSD: disklabel_scan.c,v 1.3 2009/01/18 12:13:03 lukem Exp $");
     38 #endif
     39 
     40 #include <string.h>
     41 #include <unistd.h>
     42 #include <util.h>
     43 
     44 #include <sys/disklabel.h>
     45 
     46 #define SCAN_INCR	4
     47 
     48 int
     49 disklabel_scan(struct disklabel *lp, char *buf, size_t buflen)
     50 {
     51 	size_t	i;
     52 
     53 	/* scan for the correct magic numbers. */
     54 
     55 	for (i=0; i <= buflen - sizeof(*lp); i += SCAN_INCR) {
     56 		memcpy(lp, buf + i, sizeof(*lp));
     57 		if (lp->d_magic == DISKMAGIC && lp->d_magic2 == DISKMAGIC)
     58 			goto sanity;
     59 	}
     60 
     61 	return 1;
     62 
     63 sanity:
     64 	/* we've found something, let's sanity check it */
     65 	if (lp->d_npartitions > MAXPARTITIONS || disklabel_dkcksum(lp))
     66 		return 1;
     67 
     68 	return 0;
     69 }
     70