gpo: During restore clobber GPT.INI with a blank version

Generally speaking, there is not much value to keeping this file. The
display name does not ever seem to be used and the version only applies
to the original domain or DC it was on. The command line option to
revert this behaviour is mostly for the tests or for having a straight
1:1 backup-restore for pure restoration.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13806

Signed-off-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

python/samba/netcmd/gpo.py

@@ -332,7 +332,8 @@ def copy_directory_remote_to_local(conn, remotedir, localdir):
 
 
 def copy_directory_local_to_remote(conn, localdir, remotedir,
-                                   ignore_existing=False):
+                                   ignore_existing_dir=False,
+                                   keep_existing_files=False):
     if not conn.chkpath(remotedir):
         conn.mkdir(remotedir)
     l_dirs = [localdir]
@@ -353,9 +354,16 @@ def copy_directory_local_to_remote(conn, localdir, remotedir,
                 try:
                     conn.mkdir(r_name)
                 except NTSTATUSError:
-                    if not ignore_existing:
+                    if not ignore_existing_dir:
                         raise
             else:
+                if keep_existing_files:
+                    try:
+                        conn.loadfile(r_name)
+                        continue
+                    except NTSTATUSError:
+                        pass
+
                 data = open(l_name, 'rb').read()
                 conn.savefile(r_name, data)
 
@@ -1296,7 +1304,9 @@ class cmd_restore(cmd_create):
     takes_options = [
         Option("-H", help="LDB URL for database or target server", type=str),
         Option("--tmpdir", help="Temporary directory for copying policy files", type=str),
-        Option("--entities", help="File defining XML entities to insert into DOCTYPE header", type=str)
+        Option("--entities", help="File defining XML entities to insert into DOCTYPE header", type=str),
+        Option("--restore-metadata", help="Keep the old GPT.INI file and associated version number",
+               default=False, action="store_true")
     ]
 
     def restore_from_backup_to_local_dir(self, sourcedir, targetdir, dtd_header=''):
@@ -1368,7 +1378,7 @@ class cmd_restore(cmd_create):
                             self.outf.write('WARNING: Falling back to simple copy-restore.\n')
 
     def run(self, displayname, backup, H=None, tmpdir=None, entities=None, sambaopts=None, credopts=None,
-            versionopts=None):
+            versionopts=None, restore_metadata=None):
 
         dtd_header = ''
 
@@ -1405,10 +1415,13 @@ class cmd_restore(cmd_create):
             self.restore_from_backup_to_local_dir(backup, self.gpodir,
                                                   dtd_header)
 
+            keep_new_files = not restore_metadata
+
             # Copy GPO files over SMB
             copy_directory_local_to_remote(self.conn, self.gpodir,
                                            self.sharepath,
-                                           ignore_existing=True)
+                                           ignore_existing_dir=True,
+                                           keep_existing_files=keep_new_files)
 
             gpo_dn = get_gpo_dn(self.samdb, self.gpo_name)