Revert "Improve VMDK extent descriptor parsing (#44)"

This reverts commit 8ad6252.

Author: Miauwkeru

dissect/hypervisor/disk/vmdk.py

@@ -1,13 +1,10 @@
-from __future__ import annotations
-
 import ctypes
 import io
 import logging
 import os
 import textwrap
 import zlib
 from bisect import bisect_right
-from dataclasses import dataclass
 from functools import lru_cache
 from pathlib import Path
 
@@ -62,13 +59,13 @@ def __init__(self, fh):
                 if self.descriptor.attr["parentCID"] != "ffffffff":
                     self.parent = open_parent(path.parent, self.descriptor.attr["parentFileNameHint"])
 
-                for extent in self.descriptor.extents:
-                    if extent.type in ["SPARSE", "VMFSSPARSE", "SESPARSE"]:
-                        sdisk_fh = path.with_name(extent.filename).open("rb")
+                for _, size, extent_type, filename in self.descriptor.extents:
+                    if extent_type in ["SPARSE", "VMFSSPARSE", "SESPARSE"]:
+                        sdisk_fh = path.with_name(filename).open("rb")
                         self.disks.append(SparseDisk(sdisk_fh, parent=self.parent))
-                    elif extent.type in ["VMFS", "FLAT"]:
-                        rdisk_fh = path.with_name(extent.filename).open("rb")
-                        self.disks.append(RawDisk(rdisk_fh, extent.sectors * SECTOR_SIZE))
+                    elif extent_type in ["VMFS", "FLAT"]:
+                        rdisk_fh = path.with_name(filename).open("rb")
+                        self.disks.append(RawDisk(rdisk_fh, size * SECTOR_SIZE))
 
             elif magic in (COWD_MAGIC, VMDK_MAGIC, SESPARSE_MAGIC):
                 sparse_disk = SparseDisk(fh)
@@ -401,53 +398,18 @@ def __getattr__(self, attr):
         return getattr(self.hdr, attr)
 
 
-@dataclass
-class ExtentDescriptor:
-    access_mode: str
-    sectors: int
-    type: str
-    filename: str | None = None
-    start_sector: int | None = None
-    partition_uuid: str | None = None
-    device_identifier: str | None = None
-
-    def __post_init__(self) -> None:
-        self._raw = " ".join(map(str, [v for v in self.__dict__.values() if v is not None]))
-        self.sectors = int(self.sectors)
-
-        if self.filename:
-            self.filename = self.filename.strip('"')
-
-        if self.start_sector:
-            self.start_sector = int(self.start_sector)
-
-    def __repr__(self) -> str:
-        return f"<ExtentDescriptor {self._raw}>"
-
-    def __str__(self) -> str:
-        return self._raw
-
-
 class DiskDescriptor:
-    def __init__(
-        self, attr: dict, extents: list[ExtentDescriptor], disk_db: dict, sectors: int, raw_config: str | None = None
-    ):
+    def __init__(self, attr, extents, disk_db, sectors, raw_config=None):
         self.attr = attr
         self.extents = extents
         self.ddb = disk_db
         self.sectors = sectors
         self.raw = raw_config
 
     @classmethod
-    def parse(cls, vmdk_config: str) -> DiskDescriptor:
-        """Return :class:`DiskDescriptor` based on the provided ``vmdk_config``.
-
-        Resources:
-            - https://github.com/libyal/libvmdk/blob/main/documentation/VMWare%20Virtual%20Disk%20Format%20(VMDK).asciidoc
-        """  # noqa: E501
-
+    def parse(cls, vmdk_config):
         descriptor_settings = {}
-        extents: list[ExtentDescriptor] = []
+        extents = []
         disk_db = {}
         sectors = 0
 
@@ -458,16 +420,11 @@ def parse(cls, vmdk_config: str) -> DiskDescriptor:
                 continue
 
             if line.startswith("RW ") or line.startswith("RDONLY ") or line.startswith("NOACCESS "):
-                # Extent descriptors can have up to seven values according to libvmdk documentation.
-                parts = line.split(" ", maxsplit=6)
-
-                if len(parts) < 3:
-                    log.warning("Unexpected ExtentDescriptor format in vmdk config: %s, ignoring", line)
-                    continue
-
-                extent = ExtentDescriptor(*parts)
-                sectors += extent.sectors
-                extents.append(extent)
+                access_type, size, extent_type, filename = line.split(" ", 3)
+                filename = filename.strip('"')
+                size = int(size)
+                sectors += size
+                extents.append([access_type, size, extent_type, filename])
                 continue
 
             setting, _, value = line.partition("=")
@@ -481,33 +438,35 @@ def parse(cls, vmdk_config: str) -> DiskDescriptor:
 
         return cls(descriptor_settings, extents, disk_db, sectors, vmdk_config)
 
-    def __str__(self) -> str:
-        str_template = textwrap.dedent(
-            """\
-        # Disk DescriptorFile
-        version=1
-        {}
-
-        # Extent Description
-        {}
+    def __str__(self):
+        str_template = """\
+                          # Disk DescriptorFile
+                          version=1
+                          {}
 
-        # The Disk Data Base
-        #DDB
+                          # Extent Description
+                          {}
 
-        {}"""
-        )
+                          # The Disk Data Base
+                          #DDB
 
+                          {}"""
+        str_template = textwrap.dedent(str_template)
         descriptor_settings = []
         for setting, value in self.attr.items():
-            if setting != "version":
-                descriptor_settings.append(f"{setting}={value}")
+            if setting == "version":
+                continue
+            descriptor_settings.append("{}={}".format(setting, value))
         descriptor_settings = "\n".join(descriptor_settings)
 
-        extents = "\n".join(map(str, self.extents))
+        extents = []
+        for access_type, size, extent_type, filename in self.extents:
+            extents.append('{} {} {} "{}"'.format(access_type, size, extent_type, filename))
+        extents = "\n".join(extents)
 
         disk_db = []
         for setting, value in self.ddb.items():
-            disk_db.append(f'{setting} = "{value}"')
+            disk_db.append('{} = "{}"'.format(setting, value))
         disk_db = "\n".join(disk_db)
 
         return str_template.format(descriptor_settings, extents, disk_db)

tests/test_vmdk.py

@@ -1,7 +1,5 @@
-import pytest
-
 from dissect.hypervisor.disk.c_vmdk import c_vmdk
-from dissect.hypervisor.disk.vmdk import VMDK, DiskDescriptor, ExtentDescriptor
+from dissect.hypervisor.disk.vmdk import VMDK
 
 
 def test_vmdk_sesparse(sesparse_vmdk):
@@ -20,74 +18,3 @@ def test_vmdk_sesparse(sesparse_vmdk):
     assert header.version == 0x200000001
 
     assert vmdk.read(0x1000000) == b"a" * 0x1000000
-
-
-@pytest.mark.parametrize(
-    "extent_description, expected_extents",
-    [
-        (
-            'RW 123456789 SPARSE "disk.vmdk"',
-            [
-                ExtentDescriptor(
-                    access_mode="RW",
-                    sectors=123456789,
-                    type="SPARSE",
-                    filename="disk.vmdk",
-                    partition_uuid=None,
-                    device_identifier=None,
-                ),
-            ],
-        ),
-        (
-            'RW 123456789 FLAT "disk-flat.vmdk" 0',
-            [
-                ExtentDescriptor(
-                    access_mode="RW",
-                    sectors=123456789,
-                    type="FLAT",
-                    filename="disk-flat.vmdk",
-                    start_sector=0,
-                    partition_uuid=None,
-                    device_identifier=None,
-                )
-            ],
-        ),
-        (
-            "RDONLY 0 ZERO",
-            [
-                ExtentDescriptor(
-                    access_mode="RDONLY",
-                    sectors=0,
-                    type="ZERO",
-                ),
-            ],
-        ),
-        (
-            'NOACCESS 123456789 SPARSE "disk-sparse.vmdk" 123 partition-uuid device-id',
-            [
-                ExtentDescriptor(
-                    access_mode="NOACCESS",
-                    sectors=123456789,
-                    type="SPARSE",
-                    filename="disk-sparse.vmdk",
-                    start_sector=123,
-                    partition_uuid="partition-uuid",
-                    device_identifier="device-id",
-                ),
-            ],
-        ),
-        ("RW 1234567890", []),
-        ('RDONLY "file.vmdk"', []),
-        ("NOACCESS", []),
-    ],
-    ids=("sparse", "flat", "zero", "sparse-ids", "bad-1", "bad-2", "bad-3"),
-)
-def test_vmdk_extent_description(extent_description: str, expected_extents: list) -> None:
-    """test if we correctly parse VMDK sparse and flat extent descriptions.
-
-    Resources:
-        - https://github.com/libyal/libvmdk/blob/main/documentation/VMWare%20Virtual%20Disk%20Format%20(VMDK).asciidoc#22-extent-descriptions
-    """  # noqa: E501
-
-    descriptor = DiskDescriptor.parse(extent_description)
-    assert descriptor.extents == expected_extents