libfat/fat.h

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2001-2008 H. Peter Anvin - All Rights Reserved
   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, Inc., 53 Temple Place Ste 330,
   8  *   Boston MA 02111-1307, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 /*
  14  * fat.h
  15  *
  16  * Basic data structures for a FAT filesystem
  17  */
  18
  19 #ifndef FAT_H
  20 #define FAT_H
  21
  22 #include "ulint.h"
  23
  24 /* The poor excuse FAT has for a superblock -- in the boot sector */
  25 struct fat_bootsect {
  26     le8_t bsJump[3];            /* Jump to code */
  27     char bsOemName[8];          /* Formatting program */
  28     le16_t bsBytesPerSec;       /* Bytes/sector */
  29     le8_t bsSecPerClust;        /* Sectors/cluster */
  30     le16_t bsResSectors;        /* Reserved sectors */
  31     le8_t bsFATs;               /* Number of FATs */
  32     le16_t bsRootDirEnts;       /* Number of entries/root directory */
  33     le16_t bsSectors;           /* Number of sectors [1] */
  34     le8_t bsMedia;              /* Magic media type byte */
  35     le16_t bsFATsecs;           /* Sectors/FAT */
  36     le16_t bsSecPerTrack;       /* Sectors/track */
  37     le16_t bsHeads;             /* Number of heads */
  38     le32_t bsHiddenSecs;        /* Number of hidden sectors */
  39     le32_t bsHugeSectors;       /* Number of sectors [2] */
  40     union {
  41         /* FAT12/16 */
  42         struct {
  43             le8_t bsDriveNumber;        /* Drive number */
  44             le8_t bsReserved1;  /* Reserved */
  45             le8_t bsBootSignature;      /* 0x29 */
  46             le32_t bsVolumeID;  /* Volume serial number */
  47             char bsVolumeLabel[11];     /* Volume name */
  48             char bsFileSysType[8];      /* File system type */
  49
  50             le8_t bsCode[448];  /* Boot sector code */
  51         } fat16;
  52
  53         /* FAT32 */
  54         struct {
  55             le32_t bpb_fatsz32; /* Sectors/FAT */
  56             le16_t bpb_extflags;        /* Extended flags */
  57             le16_t bpb_fsver;   /* Filesystem version */
  58             le32_t bpb_rootclus;        /* Root directory cluster */
  59             le16_t bpb_fsinfo;  /* FSINFO sector number */
  60             le16_t bpb_bkbootsec;       /* Backup boot sector (superblock) */
  61             char bpb_reserved[12];
  62
  63             /* Same shit, different offset! */
  64             le8_t bsDriveNumber;        /* Drive number */
  65             le8_t bsReserved1;  /* Reserved */
  66             le8_t bsBootSignature;      /* 0x29 */
  67             le32_t bsVolumeID;  /* Volume serial number */
  68             char bsVolumeLabel[11];     /* Volume name */
  69             char bsFileSysType[8];      /* File system type */
  70
  71             le8_t bsCode[420];  /* Boot sector code */
  72         } fat32;
  73     } u;
  74
  75     le16_t bsSignature;         /* 0xAA55 */
  76 };
  77
  78 #define BS_BOOTSIGNATURE        0x29
  79 #define BS_SIGNATURE            0xAA55
  80
  81 /* A FAT filesystem directory entry */
  82
  83 struct fat_dirent {
  84     le8_t name[11];             /* Mangled filename */
  85     le8_t attribute;            /* File type/attribute */
  86     le8_t caseflags;            /* VFAT: case for basis and extension */
  87     le8_t ctime_ms;             /* ms of creation time */
  88     le32_t ctime;               /* Creation time */
  89     le16_t atime;               /* Date portion (high 16 bits) of atime */
  90     le16_t clusthi;             /* FAT32: high 16 bits of cluster */
  91     le32_t mtime;               /* Modification time */
  92     le16_t clustlo;             /* First cluster pointer */
  93     le32_t size;                /* File size (bytes) */
  94 };
  95
  96 /* A VFAT filesystem continuation entry */
  97 struct fat_vfat_slot {
  98     le8_t id;                   /* Sequence number for slot */
  99     le16_t name0[5];            /* 5 characters */
 100     le8_t attribute;            /* Attribute byte */
 101     le8_t reserved;             /* Reserved, MBZ */
 102     le8_t alias_csum;           /* Short name checksum */
 103     le16_t name5[6];            /* 6 characters */
 104     le16_t firstclust;          /* MBZ */
 105     le16_t name11[2];           /* 2 characters */
 106 };
 107
 108 #endif /* FAT_H */