Add symlink testing (#27)

* Add symlink testing

* Handle fast symlinks

* Bump version

* Fix test image generation

* Handle when the i_size is malformed and reading a fast symlink

Author: Eeems

_test_image.sh

@@ -28,6 +28,7 @@ trap "rm -r \"$tmp_dir\"" EXIT
 echo "[test] Using temporary directory: $tmp_dir"
 echo "[test] Generating files..."
 echo "hello world" >"$tmp_dir"/test.txt
+ln -s test.txt "$tmp_dir"/symlink.txt
 for i in {1..1000}; do
   echo "echo "hello world" >>'$tmp_dir/test.txt'"
 done | xargs -P "$(nproc)" -I {} bash -c '{}'
@@ -43,7 +44,7 @@ done | xargs -P "$(nproc)" -I {} bash -c '{}'
 mkimage test32 "$tmp_dir" 20 -O ^64bit
 mkimage test64 "$tmp_dir" 20 -O 64bit
 
-rm -f "$tmp_dir"/test*.txt
+rm -f "$tmp_dir"/test*.txt "$tmp_dir"/symlink.txt
 echo "[test] Generating files..."
 
 echo "[test] Making image test_htree..."

ext4/block.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 import errno
 import io
 import os

ext4/blockdescriptor.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 from ctypes import (
     c_uint16,
     c_uint32,

ext4/directory.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 from ctypes import (
     addressof,
     c_char,

ext4/enum.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 from ctypes import (
     c_uint8,
     c_uint16,

ext4/extent.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 from collections.abc import Iterator
 from ctypes import (
     c_uint16,

ext4/htree.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 import warnings
 from collections.abc import Generator
 from ctypes import (

ext4/inode.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 from __future__ import annotations
 
 import errno
@@ -74,6 +73,10 @@ class InodeError(Exception):
     pass
 
 
+class MalformedInodeError(Exception):
+    pass
+
+
 @final
 class Linux1(LittleEndianStructure):
     _pack_ = 1
@@ -482,8 +485,22 @@ def open(
 
 
 class SymbolicLink(Inode):
+    @property
+    def is_fast_symlink(self) -> bool:
+        i_blocks_lo = assert_cast(self.i_blocks_lo, int)  # pyright: ignore[reportAny]
+        return i_blocks_lo == 0 and not self.is_inline
+
     def readlink(self) -> bytes:
-        return self._open().read()
+        if not self.is_fast_symlink:
+            return self._open().read()
+
+        if self.i_size > Inode.i_block.size:
+            raise MalformedInodeError(
+                f"Fast symlink target too large: {self.i_size} > {Inode.i_block.size}"
+            )
+
+        _ = self.volume.seek(self.offset + Inode.i_block.offset)
+        return self.volume.read(self.i_size)
 
 
 class Directory(Inode):

ext4/struct.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 import ctypes
 import errno
 import warnings

ext4/superblock.py

@@ -1,4 +1,3 @@
-# pyright: reportImportCycles=false
 from ctypes import (
     c_ubyte,
     c_uint8,