rpminfo: Directory identification using mode bits

Currently, if a CPIO archive contains an entry for a directory we
attempt to identify it via nlinks. Since it should have at least two
nlinks if it's a directoy. However, I've stumbled across a case where
this is not true. By using the mode bits we should be able to correctly
identify directories without relying on nlinks.

Fixes: #37

Signed-off-by: John Andersen <[email protected]>

Author: pdxjohnny

rpmfile/__init__.py

@@ -78,8 +78,9 @@ def _read_new(cls, fileobj, magic=None):
         file_size = int(d[6], 16)
         fileobj.seek(file_size, 1)
         fileobj.seek(pad(fileobj), 1)
-        nlink = int(d[4], 16)
-        isdir = nlink == 2 and file_size == 0
+        # https://www.mankier.com/5/cpio under Old Binary Format mode bits
+        mode = int(d[1], 16)
+        isdir = mode & int("0040000", 8)
         return cls(name, file_start, file_size, initial_offset, isdir)
 
 

tests/test_extract.py

@@ -89,7 +89,7 @@ def test_zstd_xmlstarlet(self, rpmpath):
             self.assertEqual(rpm.headers.get("arch", "noarch"), b"x86_64")
 
             members = list(rpm.getmembers())
-            self.assertEqual(len(members), 15)
+            self.assertEqual(len(members), 12)
 
             with rpm.extractfile("./usr/bin/xmlstarlet") as fd:
                 calculated = hashlib.md5(fd.read()).hexdigest()