include/linux/msdos_fs.h

   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
  90 struct __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
 106 struct 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
 133 struct 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
 142 struct 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 */
 156 struct 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 */
 169 static inline int fat_valid_media(u8 media)
 170 {
 171         return 0xf8 <= media || media == 0xf0;
 172 }
 173 #endif /* !__KERNEL__ */
 174 #endif /* !_LINUX_MSDOS_FS_H */