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Diffstat (limited to 'src/include/fs/fat.h')
| -rw-r--r-- | src/include/fs/fat.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/src/include/fs/fat.h b/src/include/fs/fat.h new file mode 100644 index 0000000000..7fed6bacb3 --- /dev/null +++ b/src/include/fs/fat.h @@ -0,0 +1,100 @@ +/* + * 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) \ + (*((unsigned char *) (entry+11))) +#define FAT_DIRENTRY_VALID(entry) \ + ( ((*((unsigned char *) entry)) != 0) \ + && ((*((unsigned char *) entry)) != 0xE5) \ + && !(FAT_DIRENTRY_ATTRIB(entry) & FAT_ATTRIB_NOT_OK_MASK) ) +#define FAT_DIRENTRY_FIRST_CLUSTER(entry) \ + ((*((unsigned short *) (entry+26)))+(*((unsigned short *) (entry+20)) << 16)) +#define FAT_DIRENTRY_FILELENGTH(entry) \ + (*((unsigned long *) (entry+28))) + +#define FAT_LONGDIR_ID(entry) \ + (*((unsigned char *) (entry))) +#define FAT_LONGDIR_ALIASCHECKSUM(entry) \ + (*((unsigned char *) (entry+13))) |