99 lines
3.3 KiB
C
99 lines
3.3 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2001 Free Software Foundation, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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/*
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* Defines for the FAT BIOS Parameter Block (embedded in the first block
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* of the partition.
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*/
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typedef __signed__ char __s8;
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typedef unsigned char __u8;
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typedef __signed__ short __s16;
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typedef unsigned short __u16;
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typedef __signed__ int __s32;
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typedef unsigned int __u32;
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/* Note that some shorts are not aligned, and must therefore
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* be declared as array of two bytes.
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*/
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struct fat_bpb {
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__s8 ignored[3]; /* Boot strap short or near jump */
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__s8 system_id[8]; /* Name - can be used to special case
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partition manager volumes */
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__u16 bytes_per_sect; /* bytes per logical sector */
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__u8 sects_per_clust;/* sectors/cluster */
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__u16 reserved_sects; /* reserved sectors */
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__u8 num_fats; /* number of FATs */
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__u16 dir_entries; /* root directory entries */
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__u16 short_sectors; /* number of sectors */
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__u8 media; /* media code (unused) */
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__u16 fat_length; /* sectors/FAT */
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__u16 secs_track; /* sectors per track */
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__u16 heads; /* number of heads */
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__u32 hidden; /* hidden sectors (unused) */
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__u32 long_sectors; /* number of sectors (if short_sectors == 0) */
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/* The following fields are only used by FAT32 */
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__u32 fat32_length; /* sectors/FAT */
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__u16 flags; /* bit 8: fat mirroring, low 4: active fat */
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__u16 version; /* major, minor filesystem version */
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__u32 root_cluster; /* first cluster in root directory */
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__u16 info_sector; /* filesystem info sector */
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__u16 backup_boot; /* backup boot sector */
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__u16 reserved2[6]; /* Unused */
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} __attribute__ ((packed));
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/*
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* Defines how to differentiate a 12-bit and 16-bit FAT.
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*/
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#define FAT_MAX_12BIT_CLUST 4087 /* 4085 + 2 */
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/*
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* Defines for the file "attribute" byte
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*/
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#define FAT_ATTRIB_OK_MASK 0x37
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#define FAT_ATTRIB_NOT_OK_MASK 0xC8
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#define FAT_ATTRIB_DIR 0x10
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#define FAT_ATTRIB_LONGNAME 0x0F
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/*
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* Defines for FAT directory entries
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*/
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#define FAT_DIRENTRY_LENGTH 32
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#define FAT_DIRENTRY_ATTRIB(entry) \
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(*((unsigned char *) (entry+11)))
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#define FAT_DIRENTRY_VALID(entry) \
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( ((*((unsigned char *) entry)) != 0) \
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&& ((*((unsigned char *) entry)) != 0xE5) \
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&& !(FAT_DIRENTRY_ATTRIB(entry) & FAT_ATTRIB_NOT_OK_MASK) )
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#define FAT_DIRENTRY_FIRST_CLUSTER(entry) \
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((*((unsigned short *) (entry+26)))+(*((unsigned short *) (entry+20)) << 16))
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#define FAT_DIRENTRY_FILELENGTH(entry) \
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(*((unsigned long *) (entry+28)))
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#define FAT_LONGDIR_ID(entry) \
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(*((unsigned char *) (entry)))
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#define FAT_LONGDIR_ALIASCHECKSUM(entry) \
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(*((unsigned char *) (entry+13)))
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