replmd: replmd_process_link_attribute() returns type of change made

In order to share work across related link attribute updates, we need
replmd_process_link_attribute() to let the caller know what actually
changed.

This patch adds an extra return type that'll be used in the next patch.
What we're interested in is: the update was ignored (i.e. it's old news),
a new link attribute was added (because this affects the overall
msg/element memory), and an existing link attribute was modified (due to
how links are actually stored, this includes deleting the link, as in
reality it simply involves setting the existing link to 'inactive').

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

1 files changed, 20 insertions, 2 deletions

diff --git a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
index 58f9df9c98c..cd6e1cc0fd3 100644
--- a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
+++ b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
@@ -134,6 +134,17 @@ struct replmd_replicated_request {
 	bool fix_link_sid;
 };
 
+/*
+ * the result of replmd_process_linked_attribute(): either there was no change
+ * (update was ignored), a new link was added (either inactive or active), or
+ * an existing link was modified (active/inactive status may have changed).
+ */
+typedef enum {
+	LINK_CHANGE_NONE,
+	LINK_CHANGE_ADDED,
+	LINK_CHANGE_MODIFIED,
+} replmd_link_changed;
+
 static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar);
 static int replmd_delete_internals(struct ldb_module *module, struct ldb_request *req, bool re_delete);
 static int replmd_check_upgrade_links(struct ldb_context *ldb,
@@ -7926,7 +7937,8 @@ static int replmd_process_linked_attribute(struct ldb_module *module,
 					   struct ldb_message *msg,
 					   const struct dsdb_attribute *attr,
 					   struct la_entry *la_entry,
-					   struct ldb_request *parent)
+					   struct ldb_request *parent,
+					   replmd_link_changed *change)
 {
 	struct drsuapi_DsReplicaLinkedAttribute *la = la_entry->la;
 	struct ldb_context *ldb = ldb_module_get_ctx(module);
@@ -7945,6 +7957,8 @@ static int replmd_process_linked_attribute(struct ldb_module *module,
 	bool add_as_inactive = false;
 	WERROR status;
 
+	*change = LINK_CHANGE_NONE;
+
 	/* the value blob for the attribute holds the target object DN */
 	status = dsdb_dn_la_from_blob(ldb, attr, schema, mem_ctx,
 				      la->value.blob, &dsdb_dn);
@@ -8048,6 +8062,7 @@ static int replmd_process_linked_attribute(struct ldb_module *module,
 
 		val_to_update = pdn->v;
 		old_dsdb_dn = pdn->dsdb_dn;
+		*change = LINK_CHANGE_MODIFIED;
 
 	} else {
 		unsigned offset;
@@ -8088,6 +8103,7 @@ static int replmd_process_linked_attribute(struct ldb_module *module,
 
 		val_to_update = &old_el->values[offset];
 		old_dsdb_dn = NULL;
+		*change = LINK_CHANGE_ADDED;
 	}
 
 	/* set the link attribute's value to the info that was received */
@@ -8211,6 +8227,7 @@ static int replmd_process_la_group(struct ldb_module *module,
 	enum deletion_state deletion_state = OBJECT_NOT_DELETED;
 	struct ldb_context *ldb = ldb_module_get_ctx(module);
 	const struct dsdb_attribute *attr = NULL;
+	replmd_link_changed change_type;
 
 	/*
 	 * get the attribute being modified and the search result for the
@@ -8263,7 +8280,8 @@ static int replmd_process_la_group(struct ldb_module *module,
 		DLIST_REMOVE(la_group->la_entries, la);
 		ret = replmd_process_linked_attribute(module, tmp_ctx,
 						      replmd_private,
-						      msg, attr, la, NULL);
+						      msg, attr, la, NULL,
+						      &change_type);
 		if (ret != LDB_SUCCESS) {
 			replmd_txn_cleanup(replmd_private);
 			return ret;