Close file handles correctly on exceptions when unpacking strata

This prevents us from leaving file handles open when code throws an
exception. When the file handle is on a loopback mount, this is a real
problem because Morph then cannot unmount the image in its exception
handler. In most cases 'with' is the best option.

1 files changed, 6 insertions, 5 deletions

diff --git a/morphlib/bins.py b/morphlib/bins.py
index 71483172..95566f39 100644
--- a/morphlib/bins.py
+++ b/morphlib/bins.py
@@ -187,11 +187,12 @@ def unpack_binary_from_file(f, dirname):  # pragma: no cover
     tf.makedev = monkey_patcher(tf.makedev)
     tf.makelink = monkey_patcher(tf.makelink)
 
-    tf.extractall(path=dirname)
-    tf.close
+    try:
+        tf.extractall(path=dirname)
+    finally:
+        tf.close()
 
 
 def unpack_binary(filename, dirname):
-    f = open(filename, "rb")
-    unpack_binary_from_file(f, dirname)
-    f.close()
+    with open(filename, "rb") as f:
+        unpack_binary_from_file(f, dirname)