linux/include/linux/msdos_fs.h
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   1#ifndef _LINUX_MSDOS_FS_H
   2#define _LINUX_MSDOS_FS_H
   3
   4#include <linux/types.h>
   5#include <linux/magic.h>
   6#include <asm/byteorder.h>
   7
   8/*
   9 * The MS-DOS filesystem constants/structures
  10 */
  11
  12#define SECTOR_SIZE     512             /* sector size (bytes) */
  13#define SECTOR_BITS     9               /* log2(SECTOR_SIZE) */
  14#define MSDOS_DPB       (MSDOS_DPS)     /* dir entries per block */
  15#define MSDOS_DPB_BITS  4               /* log2(MSDOS_DPB) */
  16#define MSDOS_DPS       (SECTOR_SIZE / sizeof(struct msdos_dir_entry))
  17#define MSDOS_DPS_BITS  4               /* log2(MSDOS_DPS) */
  18#define MSDOS_LONGNAME  256             /* maximum name length */
  19#define CF_LE_W(v)      le16_to_cpu(v)
  20#define CF_LE_L(v)      le32_to_cpu(v)
  21#define CT_LE_W(v)      cpu_to_le16(v)
  22#define CT_LE_L(v)      cpu_to_le32(v)
  23
  24#define MSDOS_ROOT_INO   1      /* The root inode number */
  25#define MSDOS_FSINFO_INO 2      /* Used for managing the FSINFO block */
  26
  27#define MSDOS_DIR_BITS  5       /* log2(sizeof(struct msdos_dir_entry)) */
  28
  29/* directory limit */
  30#define FAT_MAX_DIR_ENTRIES     (65536)
  31#define FAT_MAX_DIR_SIZE        (FAT_MAX_DIR_ENTRIES << MSDOS_DIR_BITS)
  32
  33#define ATTR_NONE       0       /* no attribute bits */
  34#define ATTR_RO         1       /* read-only */
  35#define ATTR_HIDDEN     2       /* hidden */
  36#define ATTR_SYS        4       /* system */
  37#define ATTR_VOLUME     8       /* volume label */
  38#define ATTR_DIR        16      /* directory */
  39#define ATTR_ARCH       32      /* archived */
  40
  41/* attribute bits that are copied "as is" */
  42#define ATTR_UNUSED     (ATTR_VOLUME | ATTR_ARCH | ATTR_SYS | ATTR_HIDDEN)
  43/* bits that are used by the Windows 95/Windows NT extended FAT */
  44#define ATTR_EXT        (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
  45
  46#define CASE_LOWER_BASE 8       /* base is lower case */
  47#define CASE_LOWER_EXT  16      /* extension is lower case */
  48
  49#define DELETED_FLAG    0xe5    /* marks file as deleted when in name[0] */
  50#define IS_FREE(n)      (!*(n) || *(n) == DELETED_FLAG)
  51
  52#define FAT_LFN_LEN     255     /* maximum long name length */
  53#define MSDOS_NAME      11      /* maximum name length */
  54#define MSDOS_SLOTS     21      /* max # of slots for short and long names */
  55#define MSDOS_DOT       ".          "   /* ".", padded to MSDOS_NAME chars */
  56#define MSDOS_DOTDOT    "..         "   /* "..", padded to MSDOS_NAME chars */
  57
  58#define FAT_FIRST_ENT(s, x)     ((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
  59        MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))
  60
  61/* start of data cluster's entry (number of reserved clusters) */
  62#define FAT_START_ENT   2
  63
  64/* maximum number of clusters */
  65#define MAX_FAT12       0xFF4
  66#define MAX_FAT16       0xFFF4
  67#define MAX_FAT32       0x0FFFFFF6
  68#define MAX_FAT(s)      (MSDOS_SB(s)->fat_bits == 32 ? MAX_FAT32 : \
  69        MSDOS_SB(s)->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12)
  70
  71/* bad cluster mark */
  72#define BAD_FAT12       0xFF7
  73#define BAD_FAT16       0xFFF7
  74#define BAD_FAT32       0x0FFFFFF7
  75
  76/* standard EOF */
  77#define EOF_FAT12       0xFFF
  78#define EOF_FAT16       0xFFFF
  79#define EOF_FAT32       0x0FFFFFFF
  80
  81#define FAT_ENT_FREE    (0)
  82#define FAT_ENT_BAD     (BAD_FAT32)
  83#define FAT_ENT_EOF     (EOF_FAT32)
  84
  85#define FAT_FSINFO_SIG1 0x41615252
  86#define FAT_FSINFO_SIG2 0x61417272
  87#define IS_FSINFO(x)    (le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
  88                         && le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
  89
  90struct __fat_dirent {
  91        long            d_ino;
  92        __kernel_off_t  d_off;
  93        unsigned short  d_reclen;
  94        char            d_name[256]; /* We must not include limits.h! */
  95};
  96
  97/*
  98 * ioctl commands
  99 */
 100#define VFAT_IOCTL_READDIR_BOTH         _IOR('r', 1, struct __fat_dirent[2])
 101#define VFAT_IOCTL_READDIR_SHORT        _IOR('r', 2, struct __fat_dirent[2])
 102/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
 103#define FAT_IOCTL_GET_ATTRIBUTES        _IOR('r', 0x10, __u32)
 104#define FAT_IOCTL_SET_ATTRIBUTES        _IOW('r', 0x11, __u32)
 105
 106struct fat_boot_sector {
 107        __u8    ignored[3];     /* Boot strap short or near jump */
 108        __u8    system_id[8];   /* Name - can be used to special case
 109                                   partition manager volumes */
 110        __u8    sector_size[2]; /* bytes per logical sector */
 111        __u8    sec_per_clus;   /* sectors/cluster */
 112        __le16  reserved;       /* reserved sectors */
 113        __u8    fats;           /* number of FATs */
 114        __u8    dir_entries[2]; /* root directory entries */
 115        __u8    sectors[2];     /* number of sectors */
 116        __u8    media;          /* media code */
 117        __le16  fat_length;     /* sectors/FAT */
 118        __le16  secs_track;     /* sectors per track */
 119        __le16  heads;          /* number of heads */
 120        __le32  hidden;         /* hidden sectors (unused) */
 121        __le32  total_sect;     /* number of sectors (if sectors == 0) */
 122
 123        /* The following fields are only used by FAT32 */
 124        __le32  fat32_length;   /* sectors/FAT */
 125        __le16  flags;          /* bit 8: fat mirroring, low 4: active fat */
 126        __u8    version[2];     /* major, minor filesystem version */
 127        __le32  root_cluster;   /* first cluster in root directory */
 128        __le16  info_sector;    /* filesystem info sector */
 129        __le16  backup_boot;    /* backup boot sector */
 130        __le16  reserved2[6];   /* Unused */
 131};
 132
 133struct fat_boot_fsinfo {
 134        __le32   signature1;    /* 0x41615252L */
 135        __le32   reserved1[120];        /* Nothing as far as I can tell */
 136        __le32   signature2;    /* 0x61417272L */
 137        __le32   free_clusters; /* Free cluster count.  -1 if unknown */
 138        __le32   next_cluster;  /* Most recently allocated cluster */
 139        __le32   reserved2[4];
 140};
 141
 142struct msdos_dir_entry {
 143        __u8    name[MSDOS_NAME];/* name and extension */
 144        __u8    attr;           /* attribute bits */
 145        __u8    lcase;          /* Case for base and extension */
 146        __u8    ctime_cs;       /* Creation time, centiseconds (0-199) */
 147        __le16  ctime;          /* Creation time */
 148        __le16  cdate;          /* Creation date */
 149        __le16  adate;          /* Last access date */
 150        __le16  starthi;        /* High 16 bits of cluster in FAT32 */
 151        __le16  time,date,start;/* time, date and first cluster */
 152        __le32  size;           /* file size (in bytes) */
 153};
 154
 155/* Up to 13 characters of the name */
 156struct msdos_dir_slot {
 157        __u8    id;             /* sequence number for slot */
 158        __u8    name0_4[10];    /* first 5 characters in name */
 159        __u8    attr;           /* attribute byte */
 160        __u8    reserved;       /* always 0 */
 161        __u8    alias_checksum; /* checksum for 8.3 alias */
 162        __u8    name5_10[12];   /* 6 more characters in name */
 163        __le16   start;         /* starting cluster number, 0 in long slots */
 164        __u8    name11_12[4];   /* last 2 characters in name */
 165};
 166
 167#ifdef __KERNEL__
 168/* media of boot sector */
 169static inline int fat_valid_media(u8 media)
 170{
 171        return 0xf8 <= media || media == 0xf0;
 172}
 173#endif /* !__KERNEL__ */
 174#endif /* !_LINUX_MSDOS_FS_H */
 175
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