s3: let netsamlogon_cache_init() use tdb_check()

If the check fails we try to unlink the old file and
start with an empty cache.

metze
(cherry picked from commit 8f19c08072a7a6036d59cf6c2ca6ce17c74b7635)

Signed-off-by: Stefan Metzmacher <metze@samba.org>
(cherry picked from commit 8f737c3cd154f394f821b0e34ced3f84ff8773c4)

1 files changed, 42 insertions, 4 deletions

diff --git a/source3/libsmb/samlogon_cache.c b/source3/libsmb/samlogon_cache.c
index c96f5dad831..12901826eee 100644
--- a/source3/libsmb/samlogon_cache.c
+++ b/source3/libsmb/samlogon_cache.c
@@ -34,12 +34,50 @@ static TDB_CONTEXT *netsamlogon_tdb = NULL;
 
 bool netsamlogon_cache_init(void)
 {
-	if (!netsamlogon_tdb) {
-		netsamlogon_tdb = tdb_open_log(cache_path(NETSAMLOGON_TDB), 0,
-					       TDB_DEFAULT, O_RDWR | O_CREAT, 0600);
+	bool first_try = true;
+	const char *path = NULL;
+	int ret;
+	struct tdb_context *tdb;
+
+	if (netsamlogon_tdb) {
+		return true;
+	}
+
+	path = cache_path(NETSAMLOGON_TDB);
+again:
+	tdb = tdb_open_log(path, 0, TDB_DEFAULT,
+			   O_RDWR | O_CREAT, 0600);
+	if (tdb == NULL) {
+		DEBUG(0,("tdb_open_log('%s') - failed\n", path));
+		goto clear;
+	}
+
+	ret = tdb_check(tdb, NULL, NULL);
+	if (ret != 0) {
+		tdb_close(tdb);
+		DEBUG(0,("tdb_check('%s') - failed\n", path));
+		goto clear;
+	}
+
+	netsamlogon_tdb = tdb;
+	return true;
+
+clear:
+	if (!first_try) {
+		return false;
+	}
+	first_try = false;
+
+	DEBUG(0,("retry after CLEAR_IF_FIRST for '%s'\n", path));
+	tdb = tdb_open_log(path, 0, TDB_CLEAR_IF_FIRST,
+			   O_RDWR | O_CREAT, 0600);
+	if (tdb) {
+		tdb_close(tdb);
+		goto again;
 	}
+	DEBUG(0,("tdb_open_log(%s) with CLEAR_IF_FIRST - failed\n", path));
 
-	return (netsamlogon_tdb != NULL);
+	return false;
 }