s3-net: add command "net idmap check"

This is a tool to check the consistency of an idmap tdb database.

The default mode is to scan the database and list invalid entries,
e.g. records with an invalid format, or records which are valid
but for which the reverse mapping entry is missing.

With the "--repair" switch, one can enter an interactive
repair mode which will prompt for each invalid entry found
with the option to delete, skip or edit the record.

There is also a non-interactive repair mode triggered by "--auto"
which will remove all records with invalid content and fill up
mappings which are missing the reverse entry.

The "--test" parameter lets "net idmap check" only list the
changes that would be written and not actually commit them to
the database.

The "--lock" option allows to lock the database already in the
first reading traverse, in order to remove the race when the
database has to be closed and reopened again before writing
the changes.

Signed-off-by: Michael Adam <obnox@samba.org>

Autobuild-User: Michael Adam <obnox@samba.org>
Autobuild-Date: Mon Apr  4 18:21:09 CEST 2011 on sn-devel-104

source3/utils/net.h

@@ -76,6 +76,9 @@ struct net_context {
 	int opt_single_obj_repl;
 	int opt_clean_old_entries;
 	const char *opt_db;
+	int opt_lock;
+	int opt_auto;
+	int opt_repair;
 
 	int opt_have_ip;
 	struct sockaddr_storage opt_dest_ip;