netcmd: Try to improve domain backup error message

I ran this command as non-root by mistake and didn't find the error
message particularly helpful. Tweak the error message so it reminds the
user that they should be root. Also display the path we're looking for
the sam.ldb file in, to give them more clues.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13676

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Noel Power <npower@samba.org>
Autobuild-User(master): Noel Power <npower@samba.org>
Autobuild-Date(master): Mon Jan 21 16:34:06 CET 2019 on sn-devel-144

diff --git a/python/samba/netcmd/domain_backup.py b/python/samba/netcmd/domain_backup.py
index 4cacf571f3d3cfebbfe82d349f2b1a6cac46d45f..4e32b4b9b1c3ea7627c4c85db396cd0c5ef0a98c 100644 (file)
--- a/python/samba/netcmd/domain_backup.py
+++ b/python/samba/netcmd/domain_backup.py
@@ -1009,8 +1009,9 @@ class cmd_domain_backup_offline(samba.netcmd.Command):
 
         paths = samba.provision.provision_paths_from_lp(lp, lp.get('realm'))
         if not (paths.samdb and os.path.exists(paths.samdb)):
-            raise CommandError('No sam.db found.  This backup ' +
-                               'tool is only for AD DCs')
+            logger.error("No database found at {0}".format(paths.samdb))
+            raise CommandError('Please check you are root, and ' +
+                               'are running this command on an AD DC')
 
         check_targetdir(logger, targetdir)