lib/libutil/disklabel_scan.c

   1 /* $NetBSD: disklabel_scan.c,v 1.2 2008/04/28 20:23:02 martin 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 1.2 2008/04/28 20:23:02 martin 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 }