[DRAFT] Add Overlayfs implementation

[sydp]

Fixes #408

[codecov]

Codecov Report

Attention: 60 lines in your changes are missing coverage. Please review.

Comparison is base (c370d92) 88.21% compared to head (917824f) 88.02%.

Files	Patch %	Lines
dfvfs/vfs/overlay_file_entry.py	77.06%	25 Missing ⚠️
dfvfs/resolver_helpers/overlay_resolver_helper.py	0.00%	13 Missing ⚠️
dfvfs/analyzer/overlay_analyzer_helper.py	0.00%	8 Missing ⚠️
dfvfs/vfs/overlay_directory.py	88.52%	7 Missing ⚠️
dfvfs/vfs/overlay_file_system.py	89.79%	5 Missing ⚠️
dfvfs/file_io/overlay_file_io.py	96.15%	1 Missing ⚠️
dfvfs/path/overlay_path_spec.py	94.44%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #659      +/-   ##
==========================================
- Coverage   88.21%   88.02%   -0.19%     
==========================================
  Files         297      304       +7     
  Lines       12529    12814     +285     
==========================================
+ Hits        11052    11280     +228     
- Misses       1477     1534      +57     

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[sydp]

Getting errors with pyfsxfs_file_entry_get_extended_attributes.

ERROR: testFileEntryExistsByPathSpec (vfs.overlay_file_system.OverlayFileSystemTestWithXFS)
Test the file entry exists by path specification functionality.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/__w/dfvfs/dfvfs/tests/vfs/overlay_file_system.py", line 191, in testFileEntryExistsByPathSpec
    self.assertFalse(file_system.FileEntryExistsByPathSpec(path_spec))
  File "./dfvfs/vfs/overlay_file_system.py", line 82, in FileEntryExistsByPathSpec
    return self.GetFileEntryByPathSpec(path_spec)
  File "./dfvfs/vfs/overlay_file_system.py", line 106, in GetFileEntryByPathSpec
    for entry in overlay_dir.entries:
  File "./dfvfs/vfs/overlay_directory.py", line 118, in _EntriesGenerator
    yield from self._ReadDirectory(location)
  File "./dfvfs/vfs/overlay_directory.py", line 58, in _ReadDirectory
    for attribute in layer_file_entry.attributes:
  File "./dfvfs/vfs/file_entry.py", line 198, in attributes
    return self._GetAttributes()
  File "./dfvfs/vfs/xfs_file_entry.py", line 87, in _GetAttributes
    self._fsxfs_file_entry.extended_attributes):
OSError: pyfsxfs_file_entry_get_extended_attributes: unable to retrieve number of extended attributes. libcdata_array_get_number_of_entries: invalid array. libfsxfs_inode_get_number_of_attributes_extents: unable to retrieve number of attributes entries. libfsxfs_attributes_get_from_block: unable to retrieve number of attributes extents. libfsxfs_attributes_get_from_inode: unable to retrieve extended attributes from attributes block: 0. libfsxfs_internal_file_entry_get_extended_attributes: unable to retrieve extended attributes from inode. libfsxfs_file_entry_get_number_of_extended_attributes: unable to determine extended attributes.

======================================================================
ERROR: testGetFileEntryByPathSpec (vfs.overlay_file_system.OverlayFileSystemTestWithXFS)
Tests the GetFileEntryByPathSpec function.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/__w/dfvfs/dfvfs/tests/vfs/overlay_file_system.py", line 232, in testGetFileEntryByPathSpec
    file_entry = file_system.GetFileEntryByPathSpec(path_spec)
  File "./dfvfs/vfs/overlay_file_system.py", line 106, in GetFileEntryByPathSpec
    for entry in overlay_dir.entries:
  File "./dfvfs/vfs/overlay_directory.py", line 118, in _EntriesGenerator
    yield from self._ReadDirectory(location)
  File "./dfvfs/vfs/overlay_directory.py", line 58, in _ReadDirectory
    for attribute in layer_file_entry.attributes:
  File "./dfvfs/vfs/file_entry.py", line 198, in attributes
    return self._GetAttributes()
  File "./dfvfs/vfs/xfs_file_entry.py", line 87, in _GetAttributes
    self._fsxfs_file_entry.extended_attributes):
OSError: pyfsxfs_file_entry_get_extended_attributes: unable to retrieve number of extended attributes. libcdata_array_get_number_of_entries: invalid array. libfsxfs_inode_get_number_of_attributes_extents: unable to retrieve number of attributes entries. libfsxfs_attributes_get_from_block: unable to retrieve number of attributes extents. libfsxfs_attributes_get_from_inode: unable to retrieve extended attributes from attributes block: 0. libfsxfs_internal_file_entry_get_extended_attributes: unable to retrieve extended attributes from inode. libfsxfs_file_entry_get_number_of_extended_attributes: unable to determine extended attributes.

[joachimmetz]

I know this PR is still in draft but I recommend to rename overlay.dd to overlay_ext4.dd

[joachimmetz]

@sydp what is the status of this PR?

[sydp]

@sydp what is the status of this PR?

As discussed will get this ready for review.