s4-dsdb: setup a one_way_link attribute on schema attributes

this allows us to quickly determine if a DN is a one way link

Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>
Pair-Programmed-With: Amitay Isaacs <amitay@gmail.com>

2 files changed, 30 insertions, 0 deletions

diff --git a/source4/dsdb/schema/schema.h b/source4/dsdb/schema/schema.h
index 75351798c2..289fd4276c 100644
--- a/source4/dsdb/schema/schema.h
+++ b/source4/dsdb/schema/schema.h
@@ -107,6 +107,8 @@ struct dsdb_attribute {
 	bool isDefunct;
 	bool systemOnly;
 
+	bool one_way_link;
+
 	/* internal stuff */
 	const struct dsdb_syntax *syntax;
 	const struct ldb_schema_attribute *ldb_schema_attribute;
diff --git a/source4/dsdb/schema/schema_inferiors.c b/source4/dsdb/schema/schema_inferiors.c
index d2c134ea9e..7b80c20a60 100644
--- a/source4/dsdb/schema/schema_inferiors.c
+++ b/source4/dsdb/schema/schema_inferiors.c
@@ -328,6 +328,7 @@ int schema_fill_constructed(const struct dsdb_schema *schema)
 {
 	int ret;
 	struct dsdb_class *schema_class;
+	struct dsdb_attribute *attribute;
 
 	schema_fill_from_ids(schema);
 
@@ -353,5 +354,32 @@ int schema_fill_constructed(const struct dsdb_schema *schema)
 		schema_class->posssuperiors = NULL;
 	}
 
+	/* setup fast access to one_way_link */
+	for (attribute=schema->attributes; attribute; attribute=attribute->next) {
+		if (dsdb_dn_oid_to_format(attribute->syntax->ldap_oid) == DSDB_INVALID_DN) {
+			attribute->one_way_link = false;
+			continue;
+		}
+
+		/* these are not considered to be one way links for
+		   the purpose of DN link fixups */
+		if (ldb_attr_cmp("distinguishedName", attribute->lDAPDisplayName) == 0 ||
+		    ldb_attr_cmp("objectCategory", attribute->lDAPDisplayName) == 0) {
+			attribute->one_way_link = false;
+			continue;
+		}
+
+		if (attribute->linkID == 0) {
+			attribute->one_way_link = true;
+			continue;
+		}
+		/* handle attributes with a linkID but no backlink */
+		if (dsdb_attribute_by_linkID(schema, attribute->linkID) == NULL) {
+			attribute->one_way_link = true;
+			continue;
+		}
+		attribute->one_way_link = false;
+	}
+
 	return LDB_SUCCESS;
 }