def _find_free_clusters(self, clusters_amount):
required = clusters_amount
if clusters_amount < 0:
raise ValueError("Cluster amount cannot be negative!")
if clusters_amount == 0:
return list()
free_clusters = list()
start_sector, end_sector = self._get_active_fat_start_end_sectors()
fat = self._sector_slice(start_sector, end_sector)
fat_parser = BytesParser(fat)
empty_fat_value = b'\x00' * BYTES_PER_FAT32_ENTRY
for i in range(self._first_free_cluster * BYTES_PER_FAT32_ENTRY,
len(fat), BYTES_PER_FAT32_ENTRY):
if clusters_amount == 0:
self._first_free_cluster = i // BYTES_PER_FAT32_ENTRY
self._update_first_free_cluster()
self._decrease_free_clusters_amount_by(required)
break
value = fat_parser.get_bytes(i, BYTES_PER_FAT32_ENTRY)
debug("Looking to cluster #" + str(
i // BYTES_PER_FAT32_ENTRY) + ", content: " + str(value) + (
" != " if value != empty_fat_value else " == ") + str(
empty_fat_value))
if value == empty_fat_value:
free_clusters.append(i // BYTES_PER_FAT32_ENTRY)
clusters_amount -= 1
if clusters_amount > 0:
raise ValueError("Have not found enough free clusters "
"(Required: {}, Found: {})."
.format(required, required - clusters_amount))
return free_clusters
def type(self, args):
args_splitted = args.split(" ", maxsplit=1)
if len(args) == 0:
print(TYPE_USAGE)
return
elif len(args_splitted) == 1:
encoding = 'ascii'
file_name = args_splitted[0]
else:
encoding = args_splitted[0]
file_name = " ".join(args_splitted[1:])
file = self.find(file_name, priority="file")
if file is None:
raise DirectoryBrowserError('File "' + file_name + '" not found.')
if file.is_directory:
raise DirectoryBrowserError('"' + file_name + '" is a directory.')
bytes_parser = BytesParser(file.get_file_content(self._fat_editor))
if len(args_splitted) == 1:
text = bytes_parser. \
parse_ascii_string_replace_errors(0, len(bytes_parser))
else:
text = bytes_parser.parse_string(0,
len(bytes_parser),
encoding=encoding)
print(text)
def _read_and_validate_fs_info(self):
self.scan_info("Validating FS INFO sector...")
fs_info_bytes = self._sector_slice(self._fs_info_sector)
try:
validate_fs_info(fs_info_bytes)
except ValueError:
if self._print_scan_info:
print("Incorrect format of FS Info sector, "
"FAT32 validation failed.")
self.valid = False
else:
raise FATReaderError("Incorrect format of FS Info sector, "
"image either corrupted or it's not FAT32")
else:
self.scan_info("FS INFO sector is valid.")
parser = BytesParser(fs_info_bytes)
self._free_clusters = \
parser.parse_int_unsigned(0x1e8, 4, byteorder='little')
if self._free_clusters == 0xFFFFFFFF:
self._free_clusters = -1
self._first_free_cluster = \
parser.parse_int_unsigned(0x1ec, 4, byteorder='little')
if self._first_free_cluster == 0xFFFFFFFF:
self._first_free_cluster = -1
def _get_data(self, cluster):
parser = FileBytesParser(self._fat_image_file, self._data_area_start)
start, end = self._get_cluster_start_end_relative_to_data_start(
cluster)
data = parser.get_bytes_end(start, end)
if DEBUG_MODE:
debug("Getting data from cluster " + str(cluster) + ": ")
debug("\tCluster start: " + str(self._data_area_start + start))
debug("\tCluster end: " + str(self._data_area_start + end))
debug("\tContent: " + BytesParser(data).hex_readable(0, len(data)))
return data
def _write_fat_bytes(self, cluster, bytes_):
for i in range(self.fat_amount):
debug("Writing value {} ({:d}) to FAT #{:d}".format(
BytesParser(bytes_).hex_readable(),
int.from_bytes(bytes_, byteorder='little'),
i)
)
fat_start, _ = self._get_fat_start_end_sectors(i)
value_start = self._sectors_to_bytes(fat_start) + \
cluster * BYTES_PER_FAT32_ENTRY
self._write_content_to_image(value_start, bytes_)
def get_lfn_part(entry_bytes):
debug("get_lfn_part: ")
debug("\thex: " + BytesParser(entry_bytes).hex_readable(0,
BYTES_PER_DIR_ENTRY))
utf8_chars_pos = itertools.chain(range(1, 11, 2), range(14, 26, 2),
range(28, 32, 2))
lfn_part = ""
for pos in utf8_chars_pos:
char = entry_bytes[pos:pos + 2]
if char != b'\x00\x00' and char != b'\xFF\xFF':
lfn_part += char.decode("utf_16")
else:
break
return lfn_part, entry_bytes[0x0D]
def write_to_image(self, external_path, internal_path,
directory=None) -> fsobjects.File:
"""
Writes file to image, returns File
"""
path = pathlib.Path(external_path)
if not path.exists():
raise FileNotFoundError(str(path) + " not found.")
if directory is None:
directory = find_directory(self.get_root_directory(),
internal_path)
name = ("/" + str(path.absolute()).replace("\\", "/")).split("/")[-1]
short_name = fsobjects.get_short_name(name, directory=directory)
attributes = fsobjects.DIRECTORY if path.is_dir() else 0
creation_datetime, last_access_date, modification_datetime = \
get_time_stamps(external_path)
file = fsobjects.File(
long_name=name,
short_name=short_name,
create_datetime=creation_datetime,
change_datetime=modification_datetime,
last_open_date=last_access_date,
attributes=attributes)
file.parent = directory
first_cluster, size_bytes = self._write_external_file_content(path,
file)
file._start_cluster = first_cluster
file._size_bytes = size_bytes
self._append_content_to_dir(directory, file.to_directory_entries())
if DEBUG_MODE:
print(BytesParser(self.get_data_from_cluster_chain(
directory._start_cluster)).hex_readable(0,
BYTES_PER_DIR_ENTRY))
return file
def test_file_parse(self):
file_expected = fsobjects.File('SHORT.TXT', '', fsobjects.ARCHIVE,
datetime.datetime(day=29, month=7,
year=2017, hour=14,
minute=53, second=16,
microsecond=76000),
datetime.date(day=29, month=7,
year=2017),
datetime.datetime(day=14, month=7,
year=2017, hour=20,
minute=24,
second=10),
1699)
parser = BytesParser(
b'\x53\x48\x4F\x52\x54\x20\x20\x20\x54\x58\x54\x20\x18\x4C\xA8\x76'
b'\xFD\x4A\xFD\x4A\x00\x00\x05\xA3\xEE\x4A\x55\x00\xA3\x06\x00\x00'
)
file_actual = fateditor.parse_file_info(parser)
self.assertEqual(file_actual, file_expected)
def _write_content_and_get_first_cluster(self, content):
"""
Writes content and returns number of first cluster
"""
if len(content) == 0:
return -1
cluster_size = self.get_cluster_size()
clusters_required = math.ceil(len(content) / cluster_size)
clusters = self._find_free_clusters(clusters_required)
prev_cluster = -1
for content_start, cluster_num in \
zip(range(0, len(content), cluster_size), clusters):
if prev_cluster != -1:
self._write_fat_value(prev_cluster, cluster_num)
content_end = content_start + cluster_size
cluster_start, _ = self._get_cluster_start_end_relative_to_data_start(
cluster_num)
cluster_start += self._data_area_start
_ += self._data_area_start
debug("Writing from {:d} to {:d} (cluster {:d}):".format(
cluster_start, _, cluster_num))
writing_content = content[content_start:content_end]
debug(BytesParser(writing_content)
.hex_readable(0, cluster_size))
self._write_content_to_image(cluster_start, writing_content)
if DEBUG_MODE:
if self._get_data(cluster_num)[
:len(writing_content)] != \
writing_content:
raise Exception("Content written somewhere else!")
prev_cluster = cluster_num
self._write_eof_fat_value(clusters[-1])
return clusters[0]
def test_parse_date_start(self): # 09.08.2017(37) -> 37 08 09
# [0000100101001011]00000000
parser = BytesParser(b'\x09\x4B\x00')
self.assertEqual(datetime.date(year=2017, month=8, day=9),
parser.parse_date(0))
def test_parse_time_end(self): # 17:35:54
# 0000101100101000[0111101110001100]
parser = BytesParser(b'\x0B\x28\x7B\x8C')
self.assertEqual(datetime.time(hour=17, minute=35, second=54),
parser.parse_time(2))
def test_parse_time_middle(self): # 1:25:00
# 00001111[1000011001100001]1010111100000000
parser = BytesParser(b'\x0F\x86\x61\xAF\x00')
self.assertEqual(datetime.time(hour=12, minute=12, second=12),
parser.parse_time(1))
def _parse_dir_files(self, data, directory):
files = list()
long_file_name_buffer = ""
lfn_checksum_buffer = -1
for start in range(0, len(data) - BYTES_PER_DIR_ENTRY,
BYTES_PER_DIR_ENTRY):
debug('long_file_name_buffer = "' + long_file_name_buffer + '"')
debug('lfn_checksum_buffer = ' + str(lfn_checksum_buffer))
entry_bytes = data[start:start + BYTES_PER_DIR_ENTRY]
if entry_bytes[0] == 0x00:
# directory has no more entries
break
if entry_bytes[0] == 0xE5:
# unused entry
continue
if entry_bytes[0] == 0x05:
entry_bytes = b'\xe5' + entry_bytes[1:]
entry_parser = BytesParser(entry_bytes)
attributes = entry_parser.parse_int_unsigned(11, 1)
if attributes == fsobjects.LFN: # Long file name entry
lfn_part, lfn_checksum = get_lfn_part(entry_bytes)
long_file_name_buffer = lfn_part + \
long_file_name_buffer
if 0 <= lfn_checksum_buffer != lfn_checksum:
debug("Warning: checksum changed from {:d} to"
" {:d} during lfn sequence"
.format(lfn_checksum_buffer, lfn_checksum))
lfn_checksum_buffer = lfn_checksum
elif attributes & fsobjects.VOLUME_ID:
pass
else:
try:
file = self._parse_file_entry(entry_parser,
long_file_name_buffer,
lfn_checksum_buffer)
requires_size_check = self.repair_file_size_mode and \
not file.is_directory
requires_cluster_usage_logging = \
self.log_clusters_usage \
or self.log_clusters_usage_adv
if requires_cluster_usage_logging or \
requires_size_check:
cluster_size = self.get_cluster_size()
cluster_seq_num = start // cluster_size
entry_start_in_cluster = start % cluster_size
chain = self._get_cluster_chain(
directory._start_cluster)
cluster_num = \
chain[
cluster_seq_num]
start_bytes, _ = \
self._get_cluster_start_end_relative_to_data_start(
cluster_num)
entry_start = start_bytes + entry_start_in_cluster + self._data_area_start
if requires_cluster_usage_logging:
self._log_file_clusters_usage(file=file,
entry_start=entry_start)
except ValueError:
debug('Entry is "dot" entry, ignoring...')
continue
if requires_size_check:
self._repair_file_size(file, entry_start)
file.parent = directory
files.append(file)
long_file_name_buffer = ""
lfn_checksum_buffer = -1
debug(file.get_attributes_str())
return files
def test_parse_int_middle(self):
parser = BytesParser(b'\xf4\x43\xff\x57\xa3\x55')
self.assertEqual(0x57ff, parser.parse_int_unsigned(2, 2))
def test_parse_int_little_big_endian(self):
parser = BytesParser(b'\xf4\xa3\xff')
self.assertEqual(0xffa3f4, parser.parse_int_unsigned(0, 3))
def test_parse_date_middle(self): # 08.10.1998(18) -> 18 10 08
# 110110000000101010000000[0010010101001000]10101011
parser = BytesParser(b'\xd8\x0a\x80\x48\x25\xab')
self.assertEqual(datetime.date(year=1998, month=10, day=8),
parser.parse_date(3))
def test_parse_date_end(self): # 01.01.2000(20) -> 20 01 01
# 10111011110001101101010101010000010111[0010000100101000]
parser = BytesParser(b'\x2e\xf1\xb5\x54\x17\x21\x28')
self.assertEqual(datetime.date(year=2000, month=1, day=1),
parser.parse_date(5))
def test_parse_string_start(self):
parser = BytesParser("Я love Python".encode(encoding=UTF16))
self.assertEqual("Я love", parser.parse_string(0, 14, encoding=UTF16))
def test_parse_int_simple(self):
parser = BytesParser(b'\x5f')
self.assertEqual(0x5f, parser.parse_int_unsigned(0, 1))
def test_parse_string_middle(self):
parser = BytesParser("I love Python".encode(encoding=ASCII))
self.assertEqual("love", parser.parse_string(2, 4, encoding=ASCII))
def test_parse_int_start(self):
parser = BytesParser(b'\xf4\x43\xff\x57\xa3\x55')
self.assertEqual(0xff43f4, parser.parse_int_unsigned(0, 3))
def test_parse_string_end(self):
parser = BytesParser("Hello, world!".encode(encoding=ASCII))
self.assertEqual("world!", parser.parse_string(7, 6, encoding=ASCII))
def test_parse_int_end(self):
parser = BytesParser(b'\xf4\x43\xff\x57\xa3\x55')
self.assertEqual(0x55, parser.parse_int_unsigned(5, 1))
def test_parse_time_start(self): # 1:25:00
# [0010000000001011]
parser = BytesParser(b'\x20\x0b')
self.assertEqual(datetime.time(hour=1, minute=25, second=0),
parser.parse_time(0))
