mirror of
https://github.com/veracrypt/VeraCrypt.git
synced 2025-11-11 11:08:02 -06:00
387 lines
11 KiB
C++
387 lines
11 KiB
C++
/*
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Legal Notice: Some portions of the source code contained in this file were
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derived from the source code of TrueCrypt 7.1a, which is
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Copyright (c) 2003-2012 TrueCrypt Developers Association and which is
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governed by the TrueCrypt License 3.0, also from the source code of
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Encryption for the Masses 2.02a, which is Copyright (c) 1998-2000 Paul Le Roux
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and which is governed by the 'License Agreement for Encryption for the Masses'
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Modifications and additions to the original source code (contained in this file)
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and all other portions of this file are Copyright (c) 2013-2017 IDRIX
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and are governed by the Apache License 2.0 the full text of which is
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contained in the file License.txt included in VeraCrypt binary and source
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code distribution packages. */
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#include "Common/Tcdefs.h"
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#include "Platform/Platform.h"
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#include "Volume/VolumeHeader.h"
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#include "FatFormatter.h"
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#include "RandomNumberGenerator.h"
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namespace VeraCrypt
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{
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struct fatparams
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{
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char volume_name[11];
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uint32 num_sectors; /* total number of sectors */
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uint32 cluster_count; /* number of clusters */
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uint32 size_root_dir; /* size of the root directory in bytes */
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uint32 size_fat; /* size of FAT */
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uint32 fats;
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uint32 media;
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uint32 cluster_size;
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uint32 fat_length;
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uint16 dir_entries;
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uint16 sector_size;
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uint32 hidden;
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uint16 reserved;
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uint16 sectors;
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uint32 total_sect;
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uint16 heads;
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uint16 secs_track;
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};
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static void GetFatParams (fatparams * ft)
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{
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uint64 volumeSize = (uint64) ft->num_sectors * ft->sector_size;
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unsigned int fatsecs;
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if(ft->cluster_size == 0) // 'Default' cluster size
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{
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uint32 clusterSize;
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// Determine optimal cluster size to minimize FAT size (mounting delay), maximize number of files, keep 4 KB alignment, etc.
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if (volumeSize >= 2 * BYTES_PER_TB)
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clusterSize = 256 * BYTES_PER_KB;
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else if (volumeSize >= 512 * BYTES_PER_GB)
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clusterSize = 128 * BYTES_PER_KB;
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else if (volumeSize >= 128 * BYTES_PER_GB)
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clusterSize = 64 * BYTES_PER_KB;
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else if (volumeSize >= 64 * BYTES_PER_GB)
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clusterSize = 32 * BYTES_PER_KB;
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else if (volumeSize >= 32 * BYTES_PER_GB)
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clusterSize = 16 * BYTES_PER_KB;
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else if (volumeSize >= 16 * BYTES_PER_GB)
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clusterSize = 8 * BYTES_PER_KB;
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else if (volumeSize >= 512 * BYTES_PER_MB)
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clusterSize = 4 * BYTES_PER_KB;
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else if (volumeSize >= 256 * BYTES_PER_MB)
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clusterSize = 2 * BYTES_PER_KB;
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else if (volumeSize >= 1 * BYTES_PER_MB)
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clusterSize = 1 * BYTES_PER_KB;
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else
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clusterSize = 512;
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ft->cluster_size = clusterSize / ft->sector_size;
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if (ft->cluster_size == 0)
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ft->cluster_size = 1;
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if (ft->cluster_size * ft->sector_size > TC_MAX_FAT_CLUSTER_SIZE)
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ft->cluster_size = TC_MAX_FAT_CLUSTER_SIZE / ft->sector_size;
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if (ft->cluster_size > 128)
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ft->cluster_size = 128;
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}
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if (volumeSize <= TC_MAX_FAT_CLUSTER_SIZE * 4)
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ft->cluster_size = 1;
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// Geometry always set to SECTORS/1/1
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ft->secs_track = 1;
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ft->heads = 1;
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ft->dir_entries = 512;
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ft->fats = 2;
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ft->media = 0xf8;
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ft->hidden = 0;
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ft->size_root_dir = ft->dir_entries * 32;
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// FAT12
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ft->size_fat = 12;
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ft->reserved = 2;
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fatsecs = ft->num_sectors - (ft->size_root_dir + ft->sector_size - 1) / ft->sector_size - ft->reserved;
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ft->cluster_count = (int) (((int64) fatsecs * ft->sector_size) / (ft->cluster_size * ft->sector_size));
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ft->fat_length = (((ft->cluster_count * 3 + 1) >> 1) + ft->sector_size - 1) / ft->sector_size;
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if (ft->cluster_count >= 4085) // FAT16
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{
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ft->size_fat = 16;
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ft->reserved = 2;
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fatsecs = ft->num_sectors - (ft->size_root_dir + ft->sector_size - 1) / ft->sector_size - ft->reserved;
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ft->cluster_count = (int) (((int64) fatsecs * ft->sector_size) / (ft->cluster_size * ft->sector_size));
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ft->fat_length = (ft->cluster_count * 2 + ft->sector_size - 1) / ft->sector_size;
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}
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if(ft->cluster_count >= 65525) // FAT32
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{
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ft->size_fat = 32;
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ft->reserved = 32 - 1;
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do
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{
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ft->reserved++;
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fatsecs = ft->num_sectors - ft->reserved;
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ft->size_root_dir = ft->cluster_size * ft->sector_size;
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ft->cluster_count = (int) (((int64) fatsecs * ft->sector_size) / (ft->cluster_size * ft->sector_size));
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ft->fat_length = (ft->cluster_count * 4 + ft->sector_size - 1) / ft->sector_size;
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// Align data area on TC_MAX_VOLUME_SECTOR_SIZE
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} while (ft->sector_size == TC_SECTOR_SIZE_LEGACY
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&& (ft->reserved * ft->sector_size + ft->fat_length * ft->fats * ft->sector_size) % TC_MAX_VOLUME_SECTOR_SIZE != 0);
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}
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ft->cluster_count -= ft->fat_length * ft->fats / ft->cluster_size;
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if (ft->num_sectors >= 65536 || ft->size_fat == 32)
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{
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ft->sectors = 0;
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ft->total_sect = ft->num_sectors;
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}
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else
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{
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ft->sectors = (uint16) ft->num_sectors;
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ft->total_sect = 0;
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}
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}
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static void PutBoot (fatparams * ft, byte *boot, uint32 volumeId)
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{
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int cnt = 0;
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boot[cnt++] = 0xeb; /* boot jump */
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boot[cnt++] = (ft->size_fat == 32)? 0x58: 0x3c;
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boot[cnt++] = 0x90;
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memcpy (boot + cnt, "MSDOS5.0", 8); /* system id */
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cnt += 8;
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*(int16 *)(boot + cnt) = Endian::Little (ft->sector_size); /* bytes per sector */
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cnt += 2;
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boot[cnt++] = (int8) ft->cluster_size; /* sectors per cluster */
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*(int16 *)(boot + cnt) = Endian::Little (ft->reserved); /* reserved sectors */
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cnt += 2;
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boot[cnt++] = (int8) ft->fats; /* 2 fats */
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if(ft->size_fat == 32)
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{
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x00;
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}
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else
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{
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*(int16 *)(boot + cnt) = Endian::Little (ft->dir_entries); /* 512 root entries */
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cnt += 2;
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}
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*(int16 *)(boot + cnt) = Endian::Little (ft->sectors); /* # sectors */
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cnt += 2;
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boot[cnt++] = (int8) ft->media; /* media byte */
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if(ft->size_fat == 32)
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{
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x00;
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}
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else
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{
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*(uint16 *)(boot + cnt) = Endian::Little ((uint16) ft->fat_length); /* fat size */
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cnt += 2;
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}
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*(int16 *)(boot + cnt) = Endian::Little (ft->secs_track); /* # sectors per track */
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cnt += 2;
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*(int16 *)(boot + cnt) = Endian::Little (ft->heads); /* # heads */
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cnt += 2;
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*(int32 *)(boot + cnt) = Endian::Little (ft->hidden); /* # hidden sectors */
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cnt += 4;
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*(int32 *)(boot + cnt) = Endian::Little (ft->total_sect); /* # huge sectors */
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cnt += 4;
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if(ft->size_fat == 32)
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{
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*(int32 *)(boot + cnt) = Endian::Little (ft->fat_length); cnt += 4; /* fat size 32 */
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boot[cnt++] = 0x00; /* ExtFlags */
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x00; /* FSVer */
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x02; /* RootClus */
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x01; /* FSInfo */
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boot[cnt++] = 0x00;
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boot[cnt++] = 0x06; /* BkBootSec */
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boot[cnt++] = 0x00;
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memset(boot+cnt, 0, 12); cnt+=12; /* Reserved */
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}
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boot[cnt++] = 0x00; /* drive number */ // FIXED 80 > 00
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boot[cnt++] = 0x00; /* reserved */
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boot[cnt++] = 0x29; /* boot sig */
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*(int32 *)(boot + cnt) = volumeId;
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cnt += 4;
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memcpy (boot + cnt, ft->volume_name, 11); /* vol title */
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cnt += 11;
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switch(ft->size_fat) /* filesystem type */
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{
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case 12: memcpy (boot + cnt, "FAT12 ", 8); break;
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case 16: memcpy (boot + cnt, "FAT16 ", 8); break;
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case 32: memcpy (boot + cnt, "FAT32 ", 8); break;
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}
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cnt += 8;
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memset (boot + cnt, 0, ft->size_fat==32 ? 420:448); /* boot code */
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cnt += ft->size_fat==32 ? 420:448;
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boot[cnt++] = 0x55;
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boot[cnt++] = 0xaa; /* boot sig */
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}
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/* FAT32 FSInfo */
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static void PutFSInfo (byte *sector, fatparams *ft)
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{
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memset (sector, 0, ft->sector_size);
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sector[3] = 0x41; /* LeadSig */
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sector[2] = 0x61;
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sector[1] = 0x52;
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sector[0] = 0x52;
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sector[484+3] = 0x61; /* StrucSig */
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sector[484+2] = 0x41;
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sector[484+1] = 0x72;
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sector[484+0] = 0x72;
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// Free cluster count
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*(uint32 *)(sector + 488) = Endian::Little (ft->cluster_count - ft->size_root_dir / ft->sector_size / ft->cluster_size);
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// Next free cluster
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*(uint32 *)(sector + 492) = Endian::Little ((uint32) 2);
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sector[508+3] = 0xaa; /* TrailSig */
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sector[508+2] = 0x55;
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sector[508+1] = 0x00;
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sector[508+0] = 0x00;
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}
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void FatFormatter::Format (WriteSectorCallback &writeSector, uint64 deviceSize, uint32 clusterSize, uint32 sectorSize)
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{
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fatparams fatParams;
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#if TC_MAX_VOLUME_SECTOR_SIZE > 0xFFFF
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#error TC_MAX_VOLUME_SECTOR_SIZE > 0xFFFF
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#endif
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fatParams.sector_size = (uint16) sectorSize;
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if (deviceSize / fatParams.sector_size > 0xffffFFFF)
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throw ParameterIncorrect (SRC_POS);
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fatParams.num_sectors = (uint32) (deviceSize / fatParams.sector_size);
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fatParams.cluster_size = clusterSize / fatParams.sector_size;
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memcpy (fatParams.volume_name, "NO NAME ", 11);
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GetFatParams (&fatParams);
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fatparams *ft = &fatParams;
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SecureBuffer sector (ft->sector_size);
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uint32 sectorNumber = 0;
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/* Write the data area */
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sector.Zero();
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uint32 volumeId;
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RandomNumberGenerator::GetDataFast (BufferPtr ((byte *) &volumeId, sizeof (volumeId)));
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PutBoot (ft, (byte *) sector, volumeId);
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writeSector (sector); ++sectorNumber;
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/* fat32 boot area */
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if (ft->size_fat == 32)
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{
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/* fsinfo */
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PutFSInfo((byte *) sector, ft);
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writeSector (sector); ++sectorNumber;
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/* reserved */
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while (sectorNumber < 6)
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{
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sector.Zero();
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sector[508+3] = 0xaa; /* TrailSig */
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sector[508+2] = 0x55;
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writeSector (sector); ++sectorNumber;
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}
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/* bootsector backup */
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sector.Zero();
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PutBoot (ft, (byte *) sector, volumeId);
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writeSector (sector); ++sectorNumber;
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PutFSInfo((byte *) sector, ft);
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writeSector (sector); ++sectorNumber;
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}
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/* reserved */
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while (sectorNumber < (uint32)ft->reserved)
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{
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sector.Zero();
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writeSector (sector); ++sectorNumber;
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}
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/* write fat */
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for (uint32 x = 1; x <= ft->fats; x++)
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{
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for (uint32 n = 0; n < ft->fat_length; n++)
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{
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sector.Zero();
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if (n == 0)
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{
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byte fat_sig[12];
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if (ft->size_fat == 32)
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{
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fat_sig[0] = (byte) ft->media;
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fat_sig[1] = fat_sig[2] = 0xff;
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fat_sig[3] = 0x0f;
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fat_sig[4] = fat_sig[5] = fat_sig[6] = 0xff;
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fat_sig[7] = 0x0f;
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fat_sig[8] = fat_sig[9] = fat_sig[10] = 0xff;
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fat_sig[11] = 0x0f;
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memcpy (sector, fat_sig, 12);
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}
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else if (ft->size_fat == 16)
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{
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fat_sig[0] = (byte) ft->media;
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fat_sig[1] = 0xff;
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fat_sig[2] = 0xff;
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fat_sig[3] = 0xff;
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memcpy (sector, fat_sig, 4);
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}
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else if (ft->size_fat == 12)
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{
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fat_sig[0] = (byte) ft->media;
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fat_sig[1] = 0xff;
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fat_sig[2] = 0xff;
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fat_sig[3] = 0x00;
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memcpy (sector, fat_sig, 4);
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}
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}
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if (!writeSector (sector))
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return;
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}
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}
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/* write rootdir */
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for (uint32 x = 0; x < ft->size_root_dir / ft->sector_size; x++)
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{
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sector.Zero();
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if (!writeSector (sector))
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return;
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}
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}
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}
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