[elbe-devel] [PATCH 09/10] elbevalidate: add Image.read_at() method

[Thomas Weißschuh]

The perform some low-level validation add a new method to directly access the
raw image data.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh at linutronix.de>
---
 elbevalidate/__init__.py  | 4 ++++
 test/test_elbevalidate.py | 1 +
 2 files changed, 5 insertions(+)

diff --git a/elbevalidate/__init__.py b/elbevalidate/__init__.py
index dd0317297fe246cfb65f68da2fe6e26b69c818be..15184bf9bcf8df74a7fd79afd0acb86826e5bcbf 100644
--- a/elbevalidate/__init__.py
+++ b/elbevalidate/__init__.py
@@ -223,6 +223,10 @@ class Image(BlockDevice):
         finally:
             self._gfs.umount_all()
 
+    def read_at(self, count: int, offset: int) -> bytes:
+        """ Read count bytes at offset. """
+        return self._gfs.pread_device(self._gfs_blockdev, count=count, offset=offset)
+
 
 # This is a module-level API in the stdlib, so we do the same here.
 def statvfs(path: ImagePath):
diff --git a/test/test_elbevalidate.py b/test/test_elbevalidate.py
index fa05d74514272fa37534256cdc51471172f468a8..1ac844dbcc2d93f29ed4daacc1d0ef3850a8ca1f 100644
--- a/test/test_elbevalidate.py
+++ b/test/test_elbevalidate.py
@@ -118,6 +118,7 @@ def test_elbevalidate(elbevalidate, tmp_path):
         part0 = image.partitions[0]
         assert part0.type == '83'
         assert part0.size == len(part1) + 512
+        assert image.read_at(4, part0.start) == b'hsqs'  # SquashFS superblock
 
         part0_blkid = part0.blkid()
         assert part0_blkid['TYPE'] == 'squashfs'

-- 
2.48.1