lib/libukfs/ukfs_disklabel.c

   1 /*      $NetBSD$        */
   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 }