Normalize timestamps without filesystem operations

This changes the timestamp in the Python tarfile.TarInfo data structure
rather than setting the timestamp in the filesystem.

Suggested by Richard Maw.

1 files changed, 9 insertions, 4 deletions

diff --git a/morphlib/bins.py b/morphlib/bins.py
index f1d841ef..ce17d0a1 100644
--- a/morphlib/bins.py
+++ b/morphlib/bins.py
@@ -47,7 +47,7 @@ def create_chunk(rootdir, f, regexps, dump_memory_profile=None):
     # chunk artifact. This is useful to avoid problems from smallish
     # clock skew. It needs to be recent enough, however, that GNU tar
     # does not complain about an implausibly old timestamp.
-    normalized_timestamp = (683074800, 683074800)
+    normalized_timestamp = 683074800
        
     def mkrel(filename):
         assert filename.startswith(rootdir)
@@ -89,9 +89,14 @@ def create_chunk(rootdir, f, regexps, dump_memory_profile=None):
     tar = tarfile.open(fileobj=f, mode='w:gz')
     for filename in include:
         # Normalize mtime for everything.
-        if not os.path.islink(filename):
-            os.utime(filename, normalized_timestamp)
-        tar.add(filename, arcname=mkrel(filename), recursive=False)
+        tarinfo = tar.gettarinfo(filename, arcname=mkrel(filename))
+        tarinfo.ctime = normalized_timestamp
+        tarinfo.mtime = normalized_timestamp
+        if tarinfo.isreg():
+            with open(filename, 'rb') as f:
+                tar.addfile(tarinfo, fileobj=f)
+        else:
+            tar.addfile(tarinfo)
     tar.close()
 
     include.remove(rootdir)