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disklabel_scan.c revision 1.1.2.2 
      1 /* $NetBSD: disklabel_scan.c,v 1.1.2.2 2003/10/25 03:32:21 cyber 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  * 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 
     39 #include <sys/cdefs.h>
     40 #ifndef lint
     41 __COPYRIGHT(
     42 "@(#) Copyright (c) 2002\
     43 	The NetBSD Foundation, Inc.  All rights reserved.");
     44 __RCSID("$NetBSD: disklabel_scan.c,v 1.1.2.2 2003/10/25 03:32:21 cyber Exp $");
     45 #endif
     46 
     47 #include <string.h>
     48 #include <unistd.h>
     49 #include <util.h>
     50 
     51 #include <sys/disklabel.h>
     52 
     53 #define SCAN_INCR	4
     54 
     55 int
     56 disklabel_scan(struct disklabel *lp, char *buf, size_t buflen)
     57 {
     58 	int	i;
     59 
     60 	/* scan for the correct magic numbers. */
     61 
     62 	for (i=0; i <= buflen - sizeof(*lp); i += SCAN_INCR) {
     63 		memcpy(lp, buf + i, sizeof(*lp));
     64 		if (lp->d_magic == DISKMAGIC && lp->d_magic2 == DISKMAGIC)
     65 			goto sanity;
     66 	}
     67 
     68 	return 1;
     69 
     70 sanity:
     71 	/* we've found something, let's sanity check it */
     72 	if (lp->d_npartitions > MAXPARTITIONS || disklabel_dkcksum(lp))
     73 		return 1;
     74 
     75 	return 0;
     76 }
     77