pyctr.type.save.partdesc.ivfc module

exception pyctr.type.save.partdesc.ivfc.IVFCReadOnlyError

Bases: PartitionDescriptorError

The DPFS level is read-only.

class pyctr.type.save.partdesc.ivfc.IVFC(master_hash_size, lv1, lv2, lv3, lv4, descriptor_size)

Bases: NamedTuple

Parameters:

• master_hash_size (int) –

• lv1 (LevelData) –

• lv2 (LevelData) –

• lv3 (LevelData) –

• lv4 (LevelData) –

• descriptor_size (int) –

master_hash_size: int

Alias for field number 0

lv1: LevelData

Alias for field number 1

lv2: LevelData

Alias for field number 2

lv3: LevelData

Alias for field number 3

lv4: LevelData

Alias for field number 4

descriptor_size: int

Alias for field number 5

classmethod from_bytes(data)

Parameters:

data (bytes) –

to_bytes()

class pyctr.type.save.partdesc.ivfc.IVFCLevel4Reader(tree, verify=True, deep_verify=True)

Bases: RawIOBase

Parameters:

• tree (IVFCHashTree) –

• verify (bool) –

• deep_verify (bool) –

read(size=-1)

Parameters:

size (int) –

Return type:

bytes

seek(offset, whence=0)

Change stream position.

Change the stream position to the given byte offset. The offset is interpreted relative to the position indicated by whence. Values for whence are:

• 0 – start of stream (the default); offset should be zero or positive

• 1 – current stream position; offset may be negative

• 2 – end of stream; offset is usually negative

Return the new absolute position.

Parameters:

• offset (int) –

• whence (int) –

Return type:

int

write(data)

Parameters:

data (bytes) –

Return type:

int

class pyctr.type.save.partdesc.ivfc.IVFCHashTree(fp, ivfc, master_hashes, *, lv4_fp=None, update_master_hashes_callback=None)

Bases: object

Implements an IVFC hash tree. This covers levels 1, 2, and 3. IVFC Level 4 contains the actual data.

Parameters:

• fp (BinaryIO) – A file-like object with levels 1, 2, and 3. If lv4_fp is not specified, this must also contain level 4.

• master_hashes (List[bytes]) – Master hashes from the partition descriptor, which verify IVFC Level 1.

• lv4_fp (BinaryIO) – A file-like object with level 4. Only used if the DIFI header has enabled external IVFC Level 4.

• update_master_hashes_callback (Callable[[List[bytes]], None]) – Function to be called when master hashes are updated. This is used by DISA and DIFF to write the master hashes to the partition descriptor.

• ivfc (IVFC) –

get_block(level, block, *, verify=True, deep_verify=True)

Get the data from a block. The data is validated using the IVFC levels above the requested one.

Parameters:

• level (int) – Level containing the data.

• block (int) – The block to read.

• verify (bool) – Verify the block’s hash using the level above.

• deep_verify (bool) – Verify the hashes in all above levels, not just the upper.

Returns:

The data, and if the hash of it was valid. True if valid, False if invalid, None if uninitialized (expected hash is all zeros) or verify was false.

Return type:

Tuple[bytes, Optional[bool]]

write_data(level, offset, data)

Write the data to a level. This will update hashes in the above levels.

Parameters:

• level (int) – Level to write the data to.

• offset (int) – The offset to write the data to.

• data (bytes) – Data to write.

Returns: