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"""
Extension 2 (ext2) used in Linux systems
"""
from construct import *
Char = SLInt8
UChar = ULInt8
Short = SLInt16
UShort = ULInt16
Long = SLInt32
ULong = ULInt32
BlockPointer = Struct(
"block_number" / ULong,
# WARNING: unnamed field?
OnDemandPointer(this.block_number),
)
superblock = Struct(
"inodes_count" / ULong,
"blocks_count" / ULong,
"reserved_blocks_count" / ULong,
"free_blocks_count" / ULong,
"free_inodes_count" / ULong,
"first_data_block" / ULong,
"log_block_size" / Enum(ULong,
OneKB = 0,
TwoKB = 1,
FourKB = 2,
),
"log_frag_size" / Long,
"blocks_per_group" / ULong,
"frags_per_group" / ULong,
"inodes_per_group" / ULong,
"mtime" / ULong,
"wtime" / ULong,
"mnt_count" / UShort,
"max_mnt_count" / Short,
"magic" / Const(UShort, 0xEF53),
"state" / UShort,
"errors" / UShort,
Padding(2),
"lastcheck" / ULong,
"checkinterval" / ULong,
"creator_os" / ULong,
"rev_level" / ULong,
Padding(235*4),
)
group_descriptor = Struct(
"block_bitmap" / ULong,
"inode_bitmap" / ULong,
"inode_table" / ULong,
"free_blocks_count" / UShort,
"free_inodes_count" / UShort,
"used_dirs_count" / UShort,
Padding(14),
)
inode = Struct(
"mode" / FlagsEnum(UShort,
IXOTH = 0x0001,
IWOTH = 0x0002,
IROTH = 0x0004,
IRWXO = 0x0007,
IXGRP = 0x0008,
IWGRP = 0x0010,
IRGRP = 0x0020,
IRWXG = 0x0038,
IXUSR = 0x0040,
IWUSR = 0x0080,
IRUSR = 0x0100,
IRWXU = 0x01C0,
ISVTX = 0x0200,
ISGID = 0x0400,
ISUID = 0x0800,
IFIFO = 0x1000,
IFCHR = 0x2000,
IFDIR = 0x4000,
IFBLK = 0x6000,
IFREG = 0x8000,
IFLNK = 0xC000,
IFSOCK = 0xA000,
IFMT = 0xF000,
),
"uid" / UShort,
"size" / ULong,
"atime" / ULong,
"ctime" / ULong,
"mtime" / ULong,
"dtime" / ULong,
"gid" / UShort,
"links_count" / UShort,
"blocks" / ULong,
"flags" / FlagsEnum(ULong,
SecureDelete = 0x0001,
AllowUndelete = 0x0002,
Compressed = 0x0004,
Synchronous = 0x0008,
),
Padding(4),
# WARNING: doubled name
"blocks" / ULong[12],
"indirect1_block" / ULong,
"indirect2_block" / ULong,
"indirect3_block" / ULong,
"version" / ULong,
"file_acl" / ULong,
"dir_acl" / ULong,
"faddr" / ULong,
"frag" / UChar,
"fsize" / UChar,
Padding(10),
)
# special inodes
EXT2_BAD_INO = 1
EXT2_ROOT_INO = 2
EXT2_ACL_IDX_INO = 3
EXT2_ACL_DATA_INO = 4
EXT2_BOOT_LOADER_INO = 5
EXT2_UNDEL_DIR_INO = 6
EXT2_FIRST_INO = 11
directory_record = Struct(
"inode" / ULong,
"rec_length" / UShort,
"name_length" / UShort,
"name" / Bytes(this.name_length),
Padding(this.rec_length - this.name_length),
)
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