refactor(hdr): use FileSystem to report problems during extraction

Author: e3krisztian

unblob/handlers/archive/xiaomi/hdr.py

@@ -6,12 +6,17 @@
 from dissect.cstruct import Instance
 from structlog import get_logger
 
-from unblob.extractor import carve_chunk_to_file, is_safe_path
-from unblob.file_utils import File, InvalidInputFormat, iterate_file, snull
+from unblob.file_utils import (
+    File,
+    FileSystem,
+    InvalidInputFormat,
+    iterate_file,
+    snull,
+)
 from unblob.models import (
-    Chunk,
     Endian,
     Extractor,
+    ExtractResult,
     HexString,
     StructHandler,
     StructParser,
@@ -95,16 +100,13 @@ def __init__(self, header_struct: str):
         self._struct_parser = StructParser(C_DEFINITIONS)
 
     def extract(self, inpath: Path, outdir: Path):
+        fs = FileSystem(outdir)
         with File.from_path(inpath) as file:
-            for output_path, chunk in self.parse(file):
-                if not is_safe_path(outdir, output_path):
-                    logger.warning(
-                        "Path traversal attempt, discarding.", output_path=output_path
-                    )
-                    return
-                carve_chunk_to_file(outdir.joinpath(output_path), file, chunk)
-
-    def parse(self, file: File) -> Iterable[Tuple[Path, Chunk]]:
+            for output_path, start_offset, size in self.parse(file):
+                fs.carve(output_path, file, start_offset, size)
+        return ExtractResult(reports=list(fs.problems))
+
+    def parse(self, file: File) -> Iterable[Tuple[Path, int, int]]:
         header = self._struct_parser.parse(self.header_struct, file, Endian.LITTLE)
         for offset in cast(Iterable, header.blob_offsets):
             if not offset:
@@ -118,14 +120,12 @@ def parse(self, file: File) -> Iterable[Tuple[Path, Chunk]]:
             if not is_valid_blob_header(blob_header):
                 raise InvalidInputFormat("Invalid HDR blob header.")
 
-            # file.tell() points to right after the blob_header
             yield (
                 (
                     Path(snull(blob_header.name).decode("utf-8")),
-                    Chunk(
-                        start_offset=file.tell(),
-                        end_offset=file.tell() + blob_header.size,
-                    ),
+                    # file.tell() points to right after the blob_header == start_offset
+                    file.tell(),
+                    blob_header.size,
                 )
             )