downloadunpacked: extract symlinks in a tar archive as symlinks.

slapos/recipe/downloadunpacked.py

@@ -27,6 +27,7 @@
 import os
 import logging
 import shutil
+import tarfile
 import zc.buildout
 import tempfile
 import setuptools
@@ -80,7 +81,11 @@ class Recipe:
         md5sum=self.options.get('md5sum'))
     extract_dir = tempfile.mkdtemp(self.name)
     self.logger.debug('Created working directory %r' % extract_dir)
-    setuptools.archive_util.unpack_archive(path, extract_dir)
+    try:
+      patch_archive_util()
+      setuptools.archive_util.unpack_archive(path, extract_dir)
+    finally:
+      unpatch_archive_util()
 
     # Delete destination directory if exist
     if os.path.exists(self.destination):
@@ -112,3 +117,53 @@ class Recipe:
   
   def update(self):
     pass
+
+# Monkey patch to keep symlinks in tarfile
+def unpack_tarfile_patched(filename, extract_dir, progress_filter=setuptools.archive_util.default_filter):
+    """Unpack tar/tar.gz/tar.bz2 `filename` to `extract_dir`
+
+    Raises ``UnrecognizedFormat`` if `filename` is not a tarfile (as determined
+    by ``tarfile.open()``).  See ``unpack_archive()`` for an explanation
+    of the `progress_filter` argument.
+    """
+    try:
+        tarobj = tarfile.open(filename)
+    except tarfile.TarError:
+        raise setuptools.archive_util.UnrecognizedFormat(
+            "%s is not a compressed or uncompressed tar file" % (filename,)
+        )
+    with setuptools.archive_util.contextlib.closing(tarobj):
+        # don't do any chowning!
+        tarobj.chown = lambda *args: None
+        for member in tarobj:
+            name = member.name
+            # don't extract absolute paths or ones with .. in them
+            if not name.startswith('/') and '..' not in name.split('/'):
+                prelim_dst = os.path.join(extract_dir, *name.split('/'))
+
+                if member is not None and (member.isfile() or member.isdir() or member.islnk() or member.issym()):
+                    final_dst = progress_filter(name, prelim_dst)
+                    if final_dst:
+                        if final_dst.endswith(os.sep):
+                            final_dst = final_dst[:-1]
+                        try:
+                            # XXX Ugh
+                            tarobj._extract_member(member, final_dst)
+                        except tarfile.ExtractError:
+                            # chown/chmod/mkfifo/mknode/makedev failed
+                            pass
+        return True
+
+def patch_archive_util():
+  setuptools.archive_util.extraction_drivers = (
+    setuptools.archive_util.unpack_directory,
+    setuptools.archive_util.unpack_zipfile,
+    unpack_tarfile_patched,
+  )
+
+def unpatch_archive_util():
+  setuptools.archive_util.extraction_drivers = (
+    setuptools.archive_util.unpack_directory,
+    setuptools.archive_util.unpack_zipfile,
+    setuptools.archive_util.unpack_tarfile,
+  )