/*      $NetBSD: ukfs_disklabel.c,v 1.3 2011/02/22 15:42:15 pooka Exp $ */

/*
* Local copies of libutil disklabel routines.  This uncouples libukfs
* from the NetBSD-only libutil.  All identifiers are prefixed with
* ukfs or UKFS, otherwise the routines are the same.
*/

/*
* From:
* NetBSD: disklabel_scan.c,v 1.3 2009/01/18 12:13:03 lukem Exp
*/

/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Roland C. Dowdeswell.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/types.h>

#include <string.h>
#include <unistd.h>

#include "ukfs_int_disklabel.h"

#define SCAN_INCR       4

int
ukfs__disklabel_scan(struct ukfs__disklabel *lp, int *isswapped,
       char *buf, size_t buflen)
{
       size_t i;
       int imswapped;
       uint16_t npart;

       /* scan for the correct magic numbers. */

       for (i=0; i <= buflen - sizeof(*lp); i += SCAN_INCR) {
               memcpy(lp, buf + i, sizeof(*lp));
               if (lp->d_magic == UKFS_DISKMAGIC &&
                   lp->d_magic2 == UKFS_DISKMAGIC) {
                       imswapped = 0;
                       goto sanity;
               }
               if (lp->d_magic == bswap32(UKFS_DISKMAGIC) &&
                   lp->d_magic2 == bswap32(UKFS_DISKMAGIC)) {
                       imswapped = 1;
                       goto sanity;
               }
       }

       return 1;

sanity:
       if (imswapped)
               npart = bswap16(lp->d_npartitions);
       else
               npart = lp->d_npartitions;
       /* we've found something, let's sanity check it */
       if (npart > UKFS_MAXPARTITIONS
           || ukfs__disklabel_dkcksum(lp, imswapped))
               return 1;

       *isswapped = imswapped;
       return 0;
}


/*
* From:
*      $NetBSD: disklabel_dkcksum.c,v 1.4 2005/05/15 21:01:34 thorpej Exp
*/

/*-
* Copyright (c) 1991, 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

uint16_t
ukfs__disklabel_dkcksum(struct ukfs__disklabel *lp, int imswapped)
{
       uint16_t *start, *end;
       uint16_t sum;
       uint16_t npart;

       if (imswapped)
               npart = bswap16(lp->d_npartitions);
       else
               npart = lp->d_npartitions;

       sum = 0;
       start = (uint16_t *)(void *)lp;
       end = (uint16_t *)(void *)&lp->d_partitions[npart];
       while (start < end) {
               if (imswapped)
                       sum ^= bswap16(*start);
               else
                       sum ^= *start;
               start++;
       }
       return (sum);
}