add linuxnamespaces.tarinfo.XAttrTarFile

This is a mixin subclass for TarFile that enables it to restore and
apply linux extended attributes as PAX headers in the SCHILY.xattr.*
format. As a consequence, this enables us to process tar archives
containing file system capabilities.

1 files changed, 8 insertions, 6 deletions

diff --git a/examples/chroottar.py b/examples/chroottar.py
index f43add4..30017e5 100755
--- a/examples/chroottar.py
+++ b/examples/chroottar.py
@@ -20,6 +20,12 @@ import linuxnamespaces
 import linuxnamespaces.tarutils
 
 
+class TarFile(
+    linuxnamespaces.tarutils.ZstdTarFile, linuxnamespaces.tarutils.XAttrTarFile
+):
+    pass
+
+
 def main() -> None:
     parser = argparse.ArgumentParser()
     parser.add_argument(
@@ -49,9 +55,7 @@ def main() -> None:
             parentsock.close()
             # Once we drop privileges via setreuid and friends, we may become
             # unable to open basetar or to chdir to tdir, so do those early.
-            with linuxnamespaces.tarutils.ZstdTarFile.open(
-                args.basetar, "r:*"
-            ) as tarf:
+            with TarFile.open(args.basetar, "r:*") as tarf:
                 os.chdir(tdir)
                 linuxnamespaces.unshare(
                     linuxnamespaces.CloneFlags.NEWUSER
@@ -112,9 +116,7 @@ def main() -> None:
         if args.save and ret == 0:
             tmptar = f"{args.basetar}.new"
             try:
-                with linuxnamespaces.tarutils.ZstdTarFile.open(
-                    tmptar, "x:" + comptype
-                ) as tout:
+                with TarFile.open(tmptar, "x:" + comptype) as tout:
                     tout.add(tdir, ".")
                 os.rename(tmptar, args.basetar)
             except: