fat.h

Go to the documentation of this file.

/*
 *  FreeLoader
 *  Copyright (C) 1998-2003  Brian Palmer  <brianp@sginet.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#pragma once

#include <pshpack1.h>
typedef struct _FAT_BOOTSECTOR
{
    UCHAR       JumpBoot[3];                // Jump instruction to boot code
    CHAR        OemName[8];                 // "MSWIN4.1" for MS formatted volumes
    USHORT      BytesPerSector;             // Bytes per sector
    UCHAR       SectorsPerCluster;          // Number of sectors in a cluster
    USHORT      ReservedSectors;            // Reserved sectors, usually 1 (the bootsector)
    UCHAR       NumberOfFats;               // Number of FAT tables
    USHORT      RootDirEntries;             // Number of root directory entries (fat12/16)
    USHORT      TotalSectors;               // Number of total sectors on the drive, 16-bit
    UCHAR       MediaDescriptor;            // Media descriptor byte
    USHORT      SectorsPerFat;              // Sectors per FAT table (fat12/16)
    USHORT      SectorsPerTrack;            // Number of sectors in a track
    USHORT      NumberOfHeads;              // Number of heads on the disk
    ULONG       HiddenSectors;              // Hidden sectors (sectors before the partition start like the partition table)
    ULONG       TotalSectorsBig;            // This field is the new 32-bit total count of sectors on the volume
    UCHAR       DriveNumber;                // Int 0x13 drive number (e.g. 0x80)
    UCHAR       Reserved1;                  // Reserved (used by Windows NT). Code that formats FAT volumes should always set this byte to 0.
    UCHAR       BootSignature;              // Extended boot signature (0x29). This is a signature byte that indicates that the following three fields in the boot sector are present.
    ULONG       VolumeSerialNumber;         // Volume serial number
    CHAR        VolumeLabel[11];            // Volume label. This field matches the 11-byte volume label recorded in the root directory
    CHAR        FileSystemType[8];          // One of the strings "FAT12   ", "FAT16   ", or "FAT     "

    UCHAR       BootCodeAndData[448];       // The remainder of the boot sector

    USHORT      BootSectorMagic;            // 0xAA55

} FAT_BOOTSECTOR, *PFAT_BOOTSECTOR;

typedef struct _FAT32_BOOTSECTOR
{
    UCHAR       JumpBoot[3];                // Jump instruction to boot code
    CHAR        OemName[8];                 // "MSWIN4.1" for MS formatted volumes
    USHORT      BytesPerSector;             // Bytes per sector
    UCHAR       SectorsPerCluster;          // Number of sectors in a cluster
    USHORT      ReservedSectors;            // Reserved sectors, usually 1 (the bootsector)
    UCHAR       NumberOfFats;               // Number of FAT tables
    USHORT      RootDirEntries;             // Number of root directory entries (fat12/16)
    USHORT      TotalSectors;               // Number of total sectors on the drive, 16-bit
    UCHAR       MediaDescriptor;            // Media descriptor byte
    USHORT      SectorsPerFat;              // Sectors per FAT table (fat12/16)
    USHORT      SectorsPerTrack;            // Number of sectors in a track
    USHORT      NumberOfHeads;              // Number of heads on the disk
    ULONG       HiddenSectors;              // Hidden sectors (sectors before the partition start like the partition table)
    ULONG       TotalSectorsBig;            // This field is the new 32-bit total count of sectors on the volume
    ULONG       SectorsPerFatBig;           // This field is the FAT32 32-bit count of sectors occupied by ONE FAT. BPB_FATSz16 must be 0
    USHORT      ExtendedFlags;              // Extended flags (fat32)
    USHORT      FileSystemVersion;          // File system version (fat32)
    ULONG       RootDirStartCluster;        // Starting cluster of the root directory (fat32)
    USHORT      FsInfo;                     // Sector number of FSINFO structure in the reserved area of the FAT32 volume. Usually 1.
    USHORT      BackupBootSector;           // If non-zero, indicates the sector number in the reserved area of the volume of a copy of the boot record. Usually 6.
    UCHAR       Reserved[12];               // Reserved for future expansion
    UCHAR       DriveNumber;                // Int 0x13 drive number (e.g. 0x80)
    UCHAR       Reserved1;                  // Reserved (used by Windows NT). Code that formats FAT volumes should always set this byte to 0.
    UCHAR       BootSignature;              // Extended boot signature (0x29). This is a signature byte that indicates that the following three fields in the boot sector are present.
    ULONG       VolumeSerialNumber;         // Volume serial number
    CHAR        VolumeLabel[11];            // Volume label. This field matches the 11-byte volume label recorded in the root directory
    CHAR        FileSystemType[8];          // Always set to the string "FAT32   "

    UCHAR       BootCodeAndData[420];       // The remainder of the boot sector

    USHORT      BootSectorMagic;            // 0xAA55

} FAT32_BOOTSECTOR, *PFAT32_BOOTSECTOR;

typedef struct _FATX_BOOTSECTOR
{
    CHAR        FileSystemType[4];          /* String "FATX" */
    ULONG       VolumeSerialNumber;         /* Volume serial number */
    ULONG       SectorsPerCluster;          /* Number of sectors in a cluster */
    USHORT      NumberOfFats;               /* Number of FAT tables */
    ULONG       Unknown;                /* Always 0? */
    UCHAR       Unused[494];                /* Actually size should be 4078 (boot block is 4096 bytes) */

} FATX_BOOTSECTOR, *PFATX_BOOTSECTOR;

/*
 * Structure of MSDOS directory entry
 */
typedef struct //_DIRENTRY
{
    CHAR    FileName[11];   /* Filename + extension */
    UCHAR   Attr;       /* File attributes */
    UCHAR   ReservedNT; /* Reserved for use by Windows NT */
    UCHAR   TimeInTenths;   /* Millisecond stamp at file creation */
    USHORT  CreateTime; /* Time file was created */
    USHORT  CreateDate; /* Date file was created */
    USHORT  LastAccessDate; /* Date file was last accessed */
    USHORT  ClusterHigh;    /* High word of this entry's start cluster */
    USHORT  Time;       /* Time last modified */
    USHORT  Date;       /* Date last modified */
    USHORT  ClusterLow; /* First cluster number low word */
    ULONG   Size;       /* File size */
} DIRENTRY, * PDIRENTRY;

typedef struct
{
    UCHAR   SequenceNumber;     /* Sequence number for slot */
    WCHAR   Name0_4[5];     /* First 5 characters in name */
    UCHAR   EntryAttributes;    /* Attribute byte */
    UCHAR   Reserved;       /* Always 0 */
    UCHAR   AliasChecksum;      /* Checksum for 8.3 alias */
    WCHAR   Name5_10[6];        /* 6 more characters in name */
    USHORT  StartCluster;       /* Starting cluster number */
    WCHAR   Name11_12[2];       /* Last 2 characters in name */
} LFN_DIRENTRY, * PLFN_DIRENTRY;

typedef struct
{
    UCHAR   FileNameSize;   /* Size of filename (max 42) */
    UCHAR   Attr;       /* File attributes */
    CHAR    FileName[42];   /* Filename in ASCII, padded with 0xff (not zero-terminated) */
    ULONG   StartCluster;   /* Starting cluster number */
    ULONG   Size;       /* File size */
    USHORT  Time;       /* Time last modified */
    USHORT  Date;       /* Date last modified */
    USHORT  CreateTime; /* Time file was created */
    USHORT  CreateDate; /* Date file was created */
    USHORT  LastAccessTime; /* Time file was last accessed */
    USHORT  LastAccessDate; /* Date file was last accessed */
} FATX_DIRENTRY, * PFATX_DIRENTRY;
#include <poppack.h>

typedef struct _FAT_VOLUME_INFO *PFAT_VOLUME_INFO;

typedef struct
{
    UCHAR   Attributes;     /* File attributes */
    ULONG   FileSize;       /* File size */
    ULONG   FilePointer;        /* File pointer */
    ULONG*  FileFatChain;       /* File fat chain array */
    ULONG   DriveNumber;
    PFAT_VOLUME_INFO    Volume;
} FAT_FILE_INFO, * PFAT_FILE_INFO;

#define ATTR_NORMAL     0x00
#define ATTR_READONLY   0x01
#define ATTR_HIDDEN     0x02
#define ATTR_SYSTEM     0x04
#define ATTR_VOLUMENAME 0x08
#define ATTR_DIRECTORY  0x10
#define ATTR_ARCHIVE    0x20
#define ATTR_LONG_NAME  (ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUMENAME)

#define FAT12           1
#define FAT16           2
#define FAT32           3
#define FATX16          4
#define FATX32          5

#define ISFATX(FT) ((FT) == FATX16 || (FT) == FATX32)

const DEVVTBL* FatMount(ULONG DeviceId);