include/fs/fat.h

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2003  Brian Palmer  <brianp@sginet.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #ifndef __FAT_H
  21 #define __FAT_H
  22
  23 typedef struct _FAT_BOOTSECTOR
  24 {
  25         UCHAR           JumpBoot[3];                            // Jump instruction to boot code
  26         CHAR            OemName[8];                                     // "MSWIN4.1" for MS formatted volumes
  27         USHORT          BytesPerSector;                         // Bytes per sector
  28         UCHAR           SectorsPerCluster;                      // Number of sectors in a cluster
  29         USHORT          ReservedSectors;                        // Reserved sectors, usually 1 (the bootsector)
  30         UCHAR           NumberOfFats;                           // Number of FAT tables
  31         USHORT          RootDirEntries;                         // Number of root directory entries (fat12/16)
  32         USHORT          TotalSectors;                           // Number of total sectors on the drive, 16-bit
  33         UCHAR           MediaDescriptor;                        // Media descriptor byte
  34         USHORT          SectorsPerFat;                          // Sectors per FAT table (fat12/16)
  35         USHORT          SectorsPerTrack;                        // Number of sectors in a track
  36         USHORT          NumberOfHeads;                          // Number of heads on the disk
  37         ULONG           HiddenSectors;                          // Hidden sectors (sectors before the partition start like the partition table)
  38         ULONG           TotalSectorsBig;                        // This field is the new 32-bit total count of sectors on the volume
  39         UCHAR           DriveNumber;                            // Int 0x13 drive number (e.g. 0x80)
  40         UCHAR           Reserved1;                                      // Reserved (used by Windows NT). Code that formats FAT volumes should always set this byte to 0.
  41         UCHAR           BootSignature;                          // Extended boot signature (0x29). This is a signature byte that indicates that the following three fields in the boot sector are present.
  42         ULONG           VolumeSerialNumber;                     // Volume serial number
  43         CHAR            VolumeLabel[11];                        // Volume label. This field matches the 11-byte volume label recorded in the root directory
  44         CHAR            FileSystemType[8];                      // One of the strings "FAT12   ", "FAT16   ", or "FAT     "
  45
  46         UCHAR           BootCodeAndData[448];           // The remainder of the boot sector
  47
  48         USHORT          BootSectorMagic;                        // 0xAA55
  49
  50 } PACKED FAT_BOOTSECTOR, *PFAT_BOOTSECTOR;
  51
  52 typedef struct _FAT32_BOOTSECTOR
  53 {
  54         UCHAR           JumpBoot[3];                            // Jump instruction to boot code
  55         CHAR            OemName[8];                                     // "MSWIN4.1" for MS formatted volumes
  56         USHORT          BytesPerSector;                         // Bytes per sector
  57         UCHAR           SectorsPerCluster;                      // Number of sectors in a cluster
  58         USHORT          ReservedSectors;                        // Reserved sectors, usually 1 (the bootsector)
  59         UCHAR           NumberOfFats;                           // Number of FAT tables
  60         USHORT          RootDirEntries;                         // Number of root directory entries (fat12/16)
  61         USHORT          TotalSectors;                           // Number of total sectors on the drive, 16-bit
  62         UCHAR           MediaDescriptor;                        // Media descriptor byte
  63         USHORT          SectorsPerFat;                          // Sectors per FAT table (fat12/16)
  64         USHORT          SectorsPerTrack;                        // Number of sectors in a track
  65         USHORT          NumberOfHeads;                          // Number of heads on the disk
  66         ULONG           HiddenSectors;                          // Hidden sectors (sectors before the partition start like the partition table)
  67         ULONG           TotalSectorsBig;                        // This field is the new 32-bit total count of sectors on the volume
  68         ULONG           SectorsPerFatBig;                       // This field is the FAT32 32-bit count of sectors occupied by ONE FAT. BPB_FATSz16 must be 0
  69         USHORT          ExtendedFlags;                          // Extended flags (fat32)
  70         USHORT          FileSystemVersion;                      // File system version (fat32)
  71         ULONG           RootDirStartCluster;            // Starting cluster of the root directory (fat32)
  72         USHORT          FsInfo;                                         // Sector number of FSINFO structure in the reserved area of the FAT32 volume. Usually 1.
  73         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.
  74         UCHAR           Reserved[12];                           // Reserved for future expansion
  75         UCHAR           DriveNumber;                            // Int 0x13 drive number (e.g. 0x80)
  76         UCHAR           Reserved1;                                      // Reserved (used by Windows NT). Code that formats FAT volumes should always set this byte to 0.
  77         UCHAR           BootSignature;                          // Extended boot signature (0x29). This is a signature byte that indicates that the following three fields in the boot sector are present.
  78         ULONG           VolumeSerialNumber;                     // Volume serial number
  79         CHAR            VolumeLabel[11];                        // Volume label. This field matches the 11-byte volume label recorded in the root directory
  80         CHAR            FileSystemType[8];                      // Always set to the string "FAT32   "
  81
  82         UCHAR           BootCodeAndData[420];           // The remainder of the boot sector
  83
  84         USHORT          BootSectorMagic;                        // 0xAA55
  85
  86 } PACKED FAT32_BOOTSECTOR, *PFAT32_BOOTSECTOR;
  87
  88 typedef struct _FATX_BOOTSECTOR
  89 {
  90         CHAR            FileSystemType[4];                      /* String "FATX" */
  91         ULONG           VolumeSerialNumber;                     /* Volume serial number */
  92         ULONG           SectorsPerCluster;                      /* Number of sectors in a cluster */
  93         USHORT          NumberOfFats;                           /* Number of FAT tables */
  94         ULONG           Unknown;                                /* Always 0? */
  95         UCHAR           Unused[494];                            /* Actually size should be 4078 (boot block is 4096 bytes) */
  96
  97 } PACKED FATX_BOOTSECTOR, *PFATX_BOOTSECTOR;
  98
  99 /*
 100  * Structure of MSDOS directory entry
 101  */
 102 typedef struct //_DIRENTRY
 103 {
 104         CHAR    FileName[11];   /* Filename + extension */
 105         UCHAR   Attr;           /* File attributes */
 106         UCHAR   ReservedNT;     /* Reserved for use by Windows NT */
 107         UCHAR   TimeInTenths;   /* Millisecond stamp at file creation */
 108         USHORT  CreateTime;     /* Time file was created */
 109         USHORT  CreateDate;     /* Date file was created */
 110         USHORT  LastAccessDate; /* Date file was last accessed */
 111         USHORT  ClusterHigh;    /* High word of this entry's start cluster */
 112         USHORT  Time;           /* Time last modified */
 113         USHORT  Date;           /* Date last modified */
 114         USHORT  ClusterLow;     /* First cluster number low word */
 115         ULONG   Size;           /* File size */
 116 } PACKED DIRENTRY, * PDIRENTRY;
 117
 118 typedef struct
 119 {
 120         UCHAR   SequenceNumber;         /* Sequence number for slot */
 121         WCHAR   Name0_4[5];             /* First 5 characters in name */
 122         UCHAR   EntryAttributes;        /* Attribute byte */
 123         UCHAR   Reserved;               /* Always 0 */
 124         UCHAR   AliasChecksum;          /* Checksum for 8.3 alias */
 125         WCHAR   Name5_10[6];            /* 6 more characters in name */
 126         USHORT  StartCluster;           /* Starting cluster number */
 127         WCHAR   Name11_12[2];           /* Last 2 characters in name */
 128 } PACKED LFN_DIRENTRY, * PLFN_DIRENTRY;
 129
 130 typedef struct
 131 {
 132         UCHAR   FileNameSize;   /* Size of filename (max 42) */
 133         UCHAR   Attr;           /* File attributes */
 134         CHAR    FileName[42];   /* Filename in ASCII, padded with 0xff (not zero-terminated) */
 135         ULONG   StartCluster;   /* Starting cluster number */
 136         ULONG   Size;           /* File size */
 137         USHORT  Time;           /* Time last modified */
 138         USHORT  Date;           /* Date last modified */
 139         USHORT  CreateTime;     /* Time file was created */
 140         USHORT  CreateDate;     /* Date file was created */
 141         USHORT  LastAccessTime; /* Time file was last accessed */
 142         USHORT  LastAccessDate; /* Date file was last accessed */
 143 } PACKED FATX_DIRENTRY, * PFATX_DIRENTRY;
 144
 145 typedef struct
 146 {
 147         ULONG   FileSize;               /* File size */
 148         ULONG   FilePointer;            /* File pointer */
 149         ULONG*  FileFatChain;           /* File fat chain array */
 150         ULONG   DriveNumber;
 151 } FAT_FILE_INFO, * PFAT_FILE_INFO;
 152
 153
 154
 155 BOOLEAN FatOpenVolume(ULONG DriveNumber, ULONG VolumeStartSector, ULONG PartitionSectorCount);
 156 ULONG   FatDetermineFatType(PFAT_BOOTSECTOR FatBootSector, ULONG PartitionSectorCount);
 157 PVOID   FatBufferDirectory(ULONG DirectoryStartCluster, ULONG* EntryCountPointer, BOOLEAN RootDirectory);
 158 BOOLEAN FatSearchDirectoryBufferForFile(PVOID DirectoryBuffer, ULONG EntryCount, PCHAR FileName, PFAT_FILE_INFO FatFileInfoPointer);
 159 BOOLEAN FatLookupFile(PCSTR FileName, PFAT_FILE_INFO FatFileInfoPointer);
 160 void    FatParseShortFileName(PCHAR Buffer, PDIRENTRY DirEntry);
 161 BOOLEAN FatGetFatEntry(ULONG Cluster, ULONG* ClusterPointer);
 162 FILE*   FatOpenFile(PCSTR FileName);
 163 ULONG   FatCountClustersInChain(ULONG StartCluster);
 164 ULONG*  FatGetClusterChainArray(ULONG StartCluster);
 165 BOOLEAN FatReadCluster(ULONG ClusterNumber, PVOID Buffer);
 166 BOOLEAN FatReadClusterChain(ULONG StartClusterNumber, ULONG NumberOfClusters, PVOID Buffer);
 167 BOOLEAN FatReadPartialCluster(ULONG ClusterNumber, ULONG StartingOffset, ULONG Length, PVOID Buffer);
 168 BOOLEAN FatReadFile(FILE *FileHandle, ULONG BytesToRead, ULONG* BytesRead, PVOID Buffer);
 169 ULONG           FatGetFileSize(FILE *FileHandle);
 170 VOID    FatSetFilePointer(FILE *FileHandle, ULONG NewFilePointer);
 171 ULONG           FatGetFilePointer(FILE *FileHandle);
 172 BOOLEAN FatReadVolumeSectors(ULONG DriveNumber, ULONG SectorNumber, ULONG SectorCount, PVOID Buffer);
 173
 174
 175 #define ATTR_NORMAL             0x00
 176 #define ATTR_READONLY   0x01
 177 #define ATTR_HIDDEN             0x02
 178 #define ATTR_SYSTEM             0x04
 179 #define ATTR_VOLUMENAME 0x08
 180 #define ATTR_DIRECTORY  0x10
 181 #define ATTR_ARCHIVE    0x20
 182 #define ATTR_LONG_NAME  (ATTR_READONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUMENAME)
 183
 184 #define FAT12                   1
 185 #define FAT16                   2
 186 #define FAT32                   3
 187 #define FATX16                  4
 188 #define FATX32                  5
 189
 190 #define ISFATX(FT) ((FT) == FATX16 || (FT) == FATX32)
 191
 192 #endif // #defined __FAT_H