b7d6282aae
We do not have code to fix this situation, and the mismatch does not
prevent the kernel driver from consuming the file system, and some factory
formatted SD cards seem to have a garbage backup block.
This makes the code match to its comments (replacing pfatal with pwarn).
Inspired by: NetBSD r1.13
Inspired by: b47b16353f
MFC after: 2 weeks
278 lines
8.8 KiB
C
278 lines
8.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (C) 1995, 1997 Wolfgang Solfrank
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* Copyright (c) 1995 Martin Husemann
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: boot.c,v 1.11 2006/06/05 16:51:18 christos Exp ");
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <unistd.h>
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#include "ext.h"
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#include "fsutil.h"
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int
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readboot(int dosfs, struct bootblock *boot)
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{
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u_char block[DOSBOOTBLOCKSIZE];
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u_char fsinfo[2 * DOSBOOTBLOCKSIZE];
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u_char backup[DOSBOOTBLOCKSIZE];
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int ret = FSOK;
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int i;
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if ((size_t)read(dosfs, block, sizeof block) != sizeof block) {
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perr("could not read boot block");
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return FSFATAL;
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}
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if (block[510] != 0x55 || block[511] != 0xaa) {
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pfatal("Invalid signature in boot block: %02x%02x",
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block[511], block[510]);
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return FSFATAL;
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}
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memset(boot, 0, sizeof *boot);
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boot->ValidFat = -1;
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/* decode bios parameter block */
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boot->bpbBytesPerSec = block[11] + (block[12] << 8);
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boot->bpbSecPerClust = block[13];
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boot->bpbResSectors = block[14] + (block[15] << 8);
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boot->bpbFATs = block[16];
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boot->bpbRootDirEnts = block[17] + (block[18] << 8);
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boot->bpbSectors = block[19] + (block[20] << 8);
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boot->bpbMedia = block[21];
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boot->bpbFATsmall = block[22] + (block[23] << 8);
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boot->SecPerTrack = block[24] + (block[25] << 8);
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boot->bpbHeads = block[26] + (block[27] << 8);
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boot->bpbHiddenSecs = block[28] + (block[29] << 8) +
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(block[30] << 16) + (block[31] << 24);
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boot->bpbHugeSectors = block[32] + (block[33] << 8) +
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(block[34] << 16) + (block[35] << 24);
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boot->FATsecs = boot->bpbFATsmall;
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if (!boot->bpbRootDirEnts)
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boot->flags |= FAT32;
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if (boot->flags & FAT32) {
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boot->FATsecs = block[36] + (block[37] << 8)
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+ (block[38] << 16) + (block[39] << 24);
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if (block[40] & 0x80)
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boot->ValidFat = block[40] & 0x0f;
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/* check version number: */
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if (block[42] || block[43]) {
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/* Correct? XXX */
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pfatal("Unknown file system version: %x.%x",
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block[43], block[42]);
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return FSFATAL;
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}
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boot->bpbRootClust = block[44] + (block[45] << 8)
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+ (block[46] << 16) + (block[47] << 24);
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boot->bpbFSInfo = block[48] + (block[49] << 8);
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boot->bpbBackup = block[50] + (block[51] << 8);
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if (lseek(dosfs, boot->bpbFSInfo * boot->bpbBytesPerSec,
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SEEK_SET) != boot->bpbFSInfo * boot->bpbBytesPerSec
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|| read(dosfs, fsinfo, sizeof fsinfo) != sizeof fsinfo) {
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perr("could not read fsinfo block");
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return FSFATAL;
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}
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if (memcmp(fsinfo, "RRaA", 4)
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|| memcmp(fsinfo + 0x1e4, "rrAa", 4)
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|| fsinfo[0x1fc]
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|| fsinfo[0x1fd]
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|| fsinfo[0x1fe] != 0x55
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|| fsinfo[0x1ff] != 0xaa
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|| fsinfo[0x3fc]
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|| fsinfo[0x3fd]
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|| fsinfo[0x3fe] != 0x55
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|| fsinfo[0x3ff] != 0xaa) {
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pwarn("Invalid signature in fsinfo block\n");
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if (ask(0, "Fix")) {
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memcpy(fsinfo, "RRaA", 4);
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memcpy(fsinfo + 0x1e4, "rrAa", 4);
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fsinfo[0x1fc] = fsinfo[0x1fd] = 0;
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fsinfo[0x1fe] = 0x55;
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fsinfo[0x1ff] = 0xaa;
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fsinfo[0x3fc] = fsinfo[0x3fd] = 0;
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fsinfo[0x3fe] = 0x55;
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fsinfo[0x3ff] = 0xaa;
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if (lseek(dosfs, boot->bpbFSInfo *
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boot->bpbBytesPerSec, SEEK_SET)
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!= boot->bpbFSInfo * boot->bpbBytesPerSec
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|| write(dosfs, fsinfo, sizeof fsinfo)
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!= sizeof fsinfo) {
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perr("Unable to write bpbFSInfo");
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return FSFATAL;
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}
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ret = FSBOOTMOD;
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} else
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boot->bpbFSInfo = 0;
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}
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if (boot->bpbFSInfo) {
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boot->FSFree = fsinfo[0x1e8] + (fsinfo[0x1e9] << 8)
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+ (fsinfo[0x1ea] << 16)
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+ (fsinfo[0x1eb] << 24);
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boot->FSNext = fsinfo[0x1ec] + (fsinfo[0x1ed] << 8)
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+ (fsinfo[0x1ee] << 16)
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+ (fsinfo[0x1ef] << 24);
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}
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if (lseek(dosfs, boot->bpbBackup * boot->bpbBytesPerSec,
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SEEK_SET)
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!= boot->bpbBackup * boot->bpbBytesPerSec
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|| read(dosfs, backup, sizeof backup) != sizeof backup) {
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perr("could not read backup bootblock");
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return FSFATAL;
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}
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backup[65] = block[65]; /* XXX */
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if (memcmp(block + 11, backup + 11, 79)) {
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/*
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* XXX We require a reference that explains
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* that these bytes need to match, or should
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* drop the check. gdt@NetBSD has observed
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* filesystems that work fine under Windows XP
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* and NetBSD that do not match, so the
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* requirement is suspect. For now, just
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* print out useful information and continue.
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*/
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pwarn("backup (block %d) mismatch with primary bootblock:\n",
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boot->bpbBackup);
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for (i = 11; i < 11 + 90; i++) {
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if (block[i] != backup[i])
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pwarn("\ti=%d\tprimary 0x%02x\tbackup 0x%02x\n",
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i, block[i], backup[i]);
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}
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}
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/* Check backup bpbFSInfo? XXX */
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}
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boot->ClusterOffset = (boot->bpbRootDirEnts * 32 +
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boot->bpbBytesPerSec - 1) / boot->bpbBytesPerSec +
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boot->bpbResSectors + boot->bpbFATs * boot->FATsecs -
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CLUST_FIRST * boot->bpbSecPerClust;
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if (boot->bpbBytesPerSec % DOSBOOTBLOCKSIZE_REAL != 0) {
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pfatal("Invalid sector size: %u", boot->bpbBytesPerSec);
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return FSFATAL;
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}
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if (boot->bpbSecPerClust == 0) {
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pfatal("Invalid cluster size: %u", boot->bpbSecPerClust);
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return FSFATAL;
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}
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if (boot->bpbSectors) {
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boot->bpbHugeSectors = 0;
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boot->NumSectors = boot->bpbSectors;
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} else
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boot->NumSectors = boot->bpbHugeSectors;
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boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) /
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boot->bpbSecPerClust;
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if (boot->flags&FAT32)
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boot->ClustMask = CLUST32_MASK;
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else if (boot->NumClusters < (CLUST_RSRVD&CLUST12_MASK))
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boot->ClustMask = CLUST12_MASK;
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else if (boot->NumClusters < (CLUST_RSRVD&CLUST16_MASK))
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boot->ClustMask = CLUST16_MASK;
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else {
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pfatal("Filesystem too big (%u clusters) for non-FAT32 partition",
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boot->NumClusters);
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return FSFATAL;
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}
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switch (boot->ClustMask) {
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case CLUST32_MASK:
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boot->NumFatEntries = (boot->FATsecs * boot->bpbBytesPerSec) / 4;
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break;
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case CLUST16_MASK:
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boot->NumFatEntries = (boot->FATsecs * boot->bpbBytesPerSec) / 2;
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break;
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default:
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boot->NumFatEntries = (boot->FATsecs * boot->bpbBytesPerSec * 2) / 3;
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break;
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}
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if (boot->NumFatEntries < boot->NumClusters - CLUST_FIRST) {
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pfatal("FAT size too small, %u entries won't fit into %u sectors\n",
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boot->NumClusters, boot->FATsecs);
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return FSFATAL;
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}
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boot->ClusterSize = boot->bpbBytesPerSec * boot->bpbSecPerClust;
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boot->NumFiles = 1;
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boot->NumFree = 0;
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return ret;
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}
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int
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writefsinfo(int dosfs, struct bootblock *boot)
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{
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u_char fsinfo[2 * DOSBOOTBLOCKSIZE];
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if (lseek(dosfs, boot->bpbFSInfo * boot->bpbBytesPerSec, SEEK_SET)
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!= boot->bpbFSInfo * boot->bpbBytesPerSec
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|| read(dosfs, fsinfo, sizeof fsinfo) != sizeof fsinfo) {
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perr("could not read fsinfo block");
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return FSFATAL;
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}
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fsinfo[0x1e8] = (u_char)boot->FSFree;
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fsinfo[0x1e9] = (u_char)(boot->FSFree >> 8);
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fsinfo[0x1ea] = (u_char)(boot->FSFree >> 16);
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fsinfo[0x1eb] = (u_char)(boot->FSFree >> 24);
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fsinfo[0x1ec] = (u_char)boot->FSNext;
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fsinfo[0x1ed] = (u_char)(boot->FSNext >> 8);
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fsinfo[0x1ee] = (u_char)(boot->FSNext >> 16);
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fsinfo[0x1ef] = (u_char)(boot->FSNext >> 24);
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if (lseek(dosfs, boot->bpbFSInfo * boot->bpbBytesPerSec, SEEK_SET)
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!= boot->bpbFSInfo * boot->bpbBytesPerSec
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|| write(dosfs, fsinfo, sizeof fsinfo)
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!= sizeof fsinfo) {
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perr("Unable to write bpbFSInfo");
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return FSFATAL;
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}
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/*
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* Technically, we should return FSBOOTMOD here.
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*
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* However, since Win95 OSR2 (the first M$ OS that has
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* support for FAT32) doesn't maintain the FSINFO block
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* correctly, it has to be fixed pretty often.
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*
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* Therefor, we handle the FSINFO block only informally,
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* fixing it if necessary, but otherwise ignoring the
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* fact that it was incorrect.
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*/
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return 0;
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}
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