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/* $OpenBSD: boot.c,v 1.2 1996/06/23 14:30:41 deraadt Exp $ */
/* $NetBSD: boot.c,v 1.1 1996/05/14 17:39:28 ws Exp $ */
/*
* Copyright (C) 1995 Wolfgang Solfrank
* Copyright (c) 1995 Martin Husemann
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Martin Husemann
* and Wolfgang Solfrank.
* 4. 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 AUTHORS ``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 AUTHORS 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.
*/
#ifndef lint
static char rcsid[] = "$OpenBSD: boot.c,v 1.2 1996/06/23 14:30:41 deraadt Exp $";
#endif /* not lint */
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdio.h>
#include <unistd.h>
#include "ext.h"
int
readboot(dosfs, boot)
int dosfs;
struct bootblock *boot;
{
u_char block[DOSBOOTBLOCKSIZE];
int n;
if ((n = read(dosfs, block, sizeof block)) < (int)sizeof block) {
if (n < 0)
perror("could not read boot block");
else
pfatal("Short bootblock?");
return FSFATAL;
}
/* decode bios parameter block */
boot->BytesPerSec = block[11] + (block[12] << 8);
boot->SecPerClust = block[13];
boot->ResSectors = block[14] + (block[15] << 8);
boot->FATs = block[16];
boot->RootDirEnts = block[17] + (block[18] << 8);
boot->Sectors = block[19] + (block[20] << 8);
boot->Media = block[21];
boot->FATsecs = block[22] + (block[23] << 8);
boot->SecPerTrack = block[24] + (block[25] << 8);
boot->Heads = block[26] + (block[27] << 8);
boot->HiddenSecs = block[28] + (block[29] << 8) + (block[30] << 16) + (block[31] << 24);
boot->HugeSectors = block[32] + (block[33] << 8) + (block[34] << 16) + (block[35] << 24);
boot->ClusterOffset = (boot->RootDirEnts * 32 + boot->BytesPerSec - 1)
/ boot->BytesPerSec
+ boot->ResSectors
+ boot->FATs * boot->FATsecs
- CLUST_FIRST * boot->SecPerClust;
if (boot->BytesPerSec % DOSBOOTBLOCKSIZE != 0) {
pfatal("Invalid sector size: %u\n", boot->BytesPerSec);
return FSFATAL;
}
if (boot->SecPerClust == 0) {
pfatal("Invalid cluster size: %u\n", boot->SecPerClust);
return FSFATAL;
}
if (boot->Sectors) {
boot->HugeSectors = 0;
boot->NumSectors = boot->Sectors;
} else
boot->NumSectors = boot->HugeSectors;
boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) / boot->SecPerClust;
if (boot->NumClusters >= MAX12BITCLUSTERS)
boot->Is16BitFat = 1;
else
boot->Is16BitFat = 0;
if (boot->Is16BitFat)
boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec) / 2;
else
boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec * 2) / 3;
if (boot->NumFatEntries < boot->NumClusters) {
pfatal("FAT size too small, %d entries won't fit into %u sectors\n",
boot->NumClusters, boot->FATsecs);
return FSFATAL;
}
boot->ClusterSize = boot->BytesPerSec * boot->SecPerClust;
boot->NumFiles = 1;
boot->NumFree = 0;
return FSOK;
}
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