jffs2.py

ofrak.core.jffs2

Jffs2Filesystem (GenericBinary, FilesystemRoot) dataclass

Filesystem stored in a JFFS2 format.

Jffs2Packer (Packer)

Pack files into a compressed JFFS2 filesystem.

pack(self, resource, config=None) async

Pack the given resource.

Users should not call this method directly; rather, they should run Resource.run or Resource.pack.

Parameters:

Name	Type	Description	Default
resource	Resource		required
config		Optional config for packing. If an implementation provides a default, this default will always be used when config would otherwise be None. Note that a copy of the default config will be passed, so the default config values cannot be modified persistently by a component run.	None

Source code in ofrak/core/jffs2.py

async def pack(self, resource: Resource, config=None):
    jffs2_view: Jffs2Filesystem = await resource.view_as(Jffs2Filesystem)
    temp_flush_dir = await jffs2_view.flush_to_disk()
    with tempfile.NamedTemporaryFile(suffix=".sqsh", mode="rb") as temp:
        cmd = [
            "mkfs.jffs2",
            "-r",
            temp_flush_dir,
            "-o",
            temp.name,
        ]
        proc = await asyncio.create_subprocess_exec(
            *cmd,
        )
        returncode = await proc.wait()
        if proc.returncode:
            raise CalledProcessError(returncode=returncode, cmd=cmd)
        new_data = temp.read()
        # Passing in the original range effectively replaces the original data with the new data
        resource.queue_patch(Range(0, await resource.get_data_length()), new_data)

Jffs2Unpacker (Unpacker)

Unpack a JFFS2 filesystem.

unpack(self, resource, config=None) async

Unpack the given resource.

Users should not call this method directly; rather, they should run Resource.run or Resource.unpack.

Parameters:

Name	Type	Description	Default
resource	Resource	The resource that is being unpacked	required
config		Optional config for unpacking. If an implementation provides a default, this default will always be used when config would otherwise be None. Note that a copy of the default config will be passed, so the default config values cannot be modified persistently by a component run.	None

Source code in ofrak/core/jffs2.py

async def unpack(self, resource: Resource, config=None):
    with tempfile.NamedTemporaryFile() as temp_file:
        resource_data = await resource.get_data()
        temp_file.write(resource_data)
        temp_file.flush()

        with tempfile.TemporaryDirectory() as temp_flush_dir:
            cmd = [
                "jefferson",
                "--force",
                "--dest",
                temp_flush_dir,
                temp_file.name,
            ]
            proc = await asyncio.create_subprocess_exec(
                *cmd,
            )
            returncode = await proc.wait()
            if proc.returncode:
                raise CalledProcessError(returncode=returncode, cmd=cmd)

            jffs2_view = await resource.view_as(Jffs2Filesystem)
            await jffs2_view.initialize_from_disk(temp_flush_dir)