source: trunk/packages/xen-common/xen-common/tools/libfsimage/fat/fat.h @ 34

/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2001  Free Software Foundation, Inc.
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


/*
 *  Defines for the FAT BIOS Parameter Block (embedded in the first block
 *  of the partition.
 */

typedef __signed__ char __s8;
typedef unsigned char __u8;
typedef __signed__ short __s16;
typedef unsigned short __u16;
typedef __signed__ int __s32;
typedef unsigned int __u32;

/* Note that some shorts are not aligned, and must therefore
 * be declared as array of two bytes.
 */
struct fat_bpb {
        __s8    ignored[3];     /* Boot strap short or near jump */
        __s8    system_id[8];   /* Name - can be used to special case
                                   partition manager volumes */
        __u8    bytes_per_sect[2];      /* bytes per logical sector */
        __u8    sects_per_clust;/* sectors/cluster */
        __u8    reserved_sects[2];      /* reserved sectors */
        __u8    num_fats;       /* number of FATs */
        __u8    dir_entries[2]; /* root directory entries */
        __u8    short_sectors[2];       /* number of sectors */
        __u8    media;          /* media code (unused) */
        __u16   fat_length;     /* sectors/FAT */
        __u16   secs_track;     /* sectors per track */
        __u16   heads;          /* number of heads */
        __u32   hidden;         /* hidden sectors (unused) */
        __u32   long_sectors;   /* number of sectors (if short_sectors == 0) */

        /* The following fields are only used by FAT32 */
        __u32   fat32_length;   /* sectors/FAT */
        __u16   flags;          /* bit 8: fat mirroring, low 4: active fat */
        __u8    version[2];     /* major, minor filesystem version */
        __u32   root_cluster;   /* first cluster in root directory */
        __u16   info_sector;    /* filesystem info sector */
        __u16   backup_boot;    /* backup boot sector */
        __u16   reserved2[6];   /* Unused */
};

#define FAT_CVT_U16(bytarr) (* (__u16*)(bytarr))

/*
 *  Defines how to differentiate a 12-bit and 16-bit FAT.
 */

#define FAT_MAX_12BIT_CLUST       4087  /* 4085 + 2 */

/*
 *  Defines for the file "attribute" byte
 */

#define FAT_ATTRIB_OK_MASK        0x37
#define FAT_ATTRIB_NOT_OK_MASK    0xC8
#define FAT_ATTRIB_DIR            0x10
#define FAT_ATTRIB_LONGNAME       0x0F

/*
 *  Defines for FAT directory entries
 */

#define FAT_DIRENTRY_LENGTH       32

#define FAT_DIRENTRY_ATTRIB(entry) \
  (*((__u8 *) (entry+11)))
#define FAT_DIRENTRY_VALID(entry) \
  ( ((*((__u8 *) entry)) != 0) \
    && ((*((__u8 *) entry)) != 0xE5) \
    && !(FAT_DIRENTRY_ATTRIB(entry) & FAT_ATTRIB_NOT_OK_MASK) )
#define FAT_DIRENTRY_FIRST_CLUSTER(entry) \
  ((*((__u16 *) (entry+26)))+(*((__u16 *) (entry+20)) << 16))
#define FAT_DIRENTRY_FILELENGTH(entry) \
  (*((__u32 *) (entry+28)))

#define FAT_LONGDIR_ID(entry) \
  (*((__u8 *) (entry)))
#define FAT_LONGDIR_ALIASCHECKSUM(entry) \
  (*((__u8 *) (entry+13)))