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ukfs_disklabel.c revision 1.2 
      1 /*	$NetBSD: ukfs_disklabel.c,v 1.2 2009/12/03 14:23:49 pooka Exp $	*/
      2 
      3 /*
      4  * Local copies of libutil disklabel routines.  This uncouples libukfs
      5  * from the NetBSD-only libutil.  All identifiers are prefixed with
      6  * ukfs or UKFS, otherwise the routines are the same.
      7  */
      8 
      9 /*
     10  * From:
     11  * NetBSD: disklabel_scan.c,v 1.3 2009/01/18 12:13:03 lukem Exp
     12  */
     13 
     14 /*-
     15  * Copyright (c) 2002 The NetBSD Foundation, Inc.
     16  * All rights reserved.
     17  *
     18  * This code is derived from software contributed to The NetBSD Foundation
     19  * by Roland C. Dowdeswell.
     20  *
     21  * Redistribution and use in source and binary forms, with or without
     22  * modification, are permitted provided that the following conditions
     23  * are met:
     24  * 1. Redistributions of source code must retain the above copyright
     25  *    notice, this list of conditions and the following disclaimer.
     26  * 2. Redistributions in binary form must reproduce the above copyright
     27  *    notice, this list of conditions and the following disclaimer in the
     28  *    documentation and/or other materials provided with the distribution.
     29  *
     30  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     31  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     32  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     33  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     34  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     35  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     36  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     37  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     38  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     39  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     40  * POSSIBILITY OF SUCH DAMAGE.
     41  */
     42 
     43 #include <sys/types.h>
     44 
     45 #include <string.h>
     46 #include <unistd.h>
     47 
     48 #include "ukfs_int_disklabel.h"
     49 
     50 #define SCAN_INCR	4
     51 
     52 int
     53 ukfs__disklabel_scan(struct ukfs__disklabel *lp, char *buf, size_t buflen)
     54 {
     55 	size_t	i;
     56 
     57 	/* scan for the correct magic numbers. */
     58 
     59 	for (i=0; i <= buflen - sizeof(*lp); i += SCAN_INCR) {
     60 		memcpy(lp, buf + i, sizeof(*lp));
     61 		if (lp->d_magic == UKFS_DISKMAGIC &&
     62 		    lp->d_magic2 == UKFS_DISKMAGIC)
     63 			goto sanity;
     64 	}
     65 
     66 	return 1;
     67 
     68 sanity:
     69 	/* we've found something, let's sanity check it */
     70 	if (lp->d_npartitions > UKFS_MAXPARTITIONS
     71 	    || ukfs__disklabel_dkcksum(lp))
     72 		return 1;
     73 
     74 	return 0;
     75 }
     76 
     77 
     78 /*
     79  * From:
     80  *	$NetBSD: disklabel_dkcksum.c,v 1.4 2005/05/15 21:01:34 thorpej Exp
     81  */
     82 
     83 /*-
     84  * Copyright (c) 1991, 1993
     85  *	The Regents of the University of California.  All rights reserved.
     86  *
     87  * Redistribution and use in source and binary forms, with or without
     88  * modification, are permitted provided that the following conditions
     89  * are met:
     90  * 1. Redistributions of source code must retain the above copyright
     91  *    notice, this list of conditions and the following disclaimer.
     92  * 2. Redistributions in binary form must reproduce the above copyright
     93  *    notice, this list of conditions and the following disclaimer in the
     94  *    documentation and/or other materials provided with the distribution.
     95  * 3. Neither the name of the University nor the names of its contributors
     96  *    may be used to endorse or promote products derived from this software
     97  *    without specific prior written permission.
     98  *
     99  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
    100  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    101  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    102  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
    103  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    104  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
    105  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    106  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    107  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    108  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    109  * SUCH DAMAGE.
    110  */
    111 
    112 uint16_t
    113 ukfs__disklabel_dkcksum(struct ukfs__disklabel *lp)
    114 {
    115 	uint16_t *start, *end;
    116 	uint16_t sum;
    117 
    118 	sum = 0;
    119 	start = (uint16_t *)(void *)lp;
    120 	end = (uint16_t *)(void *)&lp->d_partitions[lp->d_npartitions];
    121 	while (start < end)
    122 		sum ^= *start++;
    123 	return (sum);
    124 }
    125