2 * GRUB -- GRand Unified Bootloader
3 * Copyright (C) 2001 Free Software Foundation, Inc.
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; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
23 * Defines for the FAT BIOS Parameter Block (embedded in the first block
27 typedef __signed__ char __s8;
28 typedef unsigned char __u8;
29 typedef __signed__ short __s16;
30 typedef unsigned short __u16;
31 typedef __signed__ int __s32;
32 typedef unsigned int __u32;
34 /* Note that some shorts are not aligned, and must therefore
35 * be declared as array of two bytes.
38 __s8 ignored[3]; /* Boot strap short or near jump */
39 __s8 system_id[8]; /* Name - can be used to special case
40 partition manager volumes */
41 __u16 bytes_per_sect; /* bytes per logical sector */
42 __u8 sects_per_clust;/* sectors/cluster */
43 __u16 reserved_sects; /* reserved sectors */
44 __u8 num_fats; /* number of FATs */
45 __u16 dir_entries; /* root directory entries */
46 __u16 short_sectors; /* number of sectors */
47 __u8 media; /* media code (unused) */
48 __u16 fat_length; /* sectors/FAT */
49 __u16 secs_track; /* sectors per track */
50 __u16 heads; /* number of heads */
51 __u32 hidden; /* hidden sectors (unused) */
52 __u32 long_sectors; /* number of sectors (if short_sectors == 0) */
54 /* The following fields are only used by FAT32 */
55 __u32 fat32_length; /* sectors/FAT */
56 __u16 flags; /* bit 8: fat mirroring, low 4: active fat */
57 __u16 version; /* major, minor filesystem version */
58 __u32 root_cluster; /* first cluster in root directory */
59 __u16 info_sector; /* filesystem info sector */
60 __u16 backup_boot; /* backup boot sector */
61 __u16 reserved2[6]; /* Unused */
62 } __attribute__ ((packed));
65 * Defines how to differentiate a 12-bit and 16-bit FAT.
68 #define FAT_MAX_12BIT_CLUST 4087 /* 4085 + 2 */
71 * Defines for the file "attribute" byte
74 #define FAT_ATTRIB_OK_MASK 0x37
75 #define FAT_ATTRIB_NOT_OK_MASK 0xC8
76 #define FAT_ATTRIB_DIR 0x10
77 #define FAT_ATTRIB_LONGNAME 0x0F
80 * Defines for FAT directory entries
83 #define FAT_DIRENTRY_LENGTH 32
85 #define FAT_DIRENTRY_ATTRIB(entry) \
86 (*((unsigned char *) (entry+11)))
87 #define FAT_DIRENTRY_VALID(entry) \
88 ( ((*((unsigned char *) entry)) != 0) \
89 && ((*((unsigned char *) entry)) != 0xE5) \
90 && !(FAT_DIRENTRY_ATTRIB(entry) & FAT_ATTRIB_NOT_OK_MASK) )
91 #define FAT_DIRENTRY_FIRST_CLUSTER(entry) \
92 ((*((unsigned short *) (entry+26)))+(*((unsigned short *) (entry+20)) << 16))
93 #define FAT_DIRENTRY_FILELENGTH(entry) \
94 (*((unsigned long *) (entry+28)))
96 #define FAT_LONGDIR_ID(entry) \
97 (*((unsigned char *) (entry)))
98 #define FAT_LONGDIR_ALIASCHECKSUM(entry) \
99 (*((unsigned char *) (entry+13)))