s4-ldb: added an optional operator_fn in the schema syntax

this function takes the operator being invoked, which will allow
schema functions to provide more fine grained control over
comparisons.

The key bug this was introduced to fix is the incorrect handling of
the LDB_OP_PRESENT test for deleted linked attributes. The backends
are unaware of the deleted state of these links, so they cannot do a
LDB_OP_PRESENT test on their own.

Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>

3 files changed, 25 insertions, 5 deletions

diff --git a/source4/lib/ldb/include/ldb.h b/source4/lib/ldb/include/ldb.h
index d29aed491a..c53cb7a6bf 100644
--- a/source4/lib/ldb/include/ldb.h
+++ b/source4/lib/ldb/include/ldb.h
@@ -353,6 +353,10 @@ char *ldb_binary_encode_string(TALLOC_CTX *mem_ctx, const char *string);
 */
 typedef int (*ldb_attr_handler_t)(struct ldb_context *, TALLOC_CTX *mem_ctx, const struct ldb_val *, struct ldb_val *);
 typedef int (*ldb_attr_comparison_t)(struct ldb_context *, TALLOC_CTX *mem_ctx, const struct ldb_val *, const struct ldb_val *);
+struct ldb_schema_attribute;
+typedef int (*ldb_attr_operator_t)(struct ldb_context *, enum ldb_parse_op operation,
+				   const struct ldb_schema_attribute *a,
+				   const struct ldb_val *, const struct ldb_val *, bool *matched);
 
 /*
   attribute handler structure
@@ -370,6 +374,7 @@ struct ldb_schema_syntax {
 	ldb_attr_handler_t ldif_write_fn;
 	ldb_attr_handler_t canonicalise_fn;
 	ldb_attr_comparison_t comparison_fn;
+	ldb_attr_operator_t operator_fn;
 };
 
 struct ldb_schema_attribute {
diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb.c b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
index 7f8342b067..f12bc58f65 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_tdb.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
@@ -553,8 +553,16 @@ static int msg_delete_element(struct ldb_module *module,
 	a = ldb_schema_attribute_by_name(ldb, el->name);
 
 	for (i=0;i<el->num_values;i++) {
-		if (a->syntax->comparison_fn(ldb, ldb,
-					     &el->values[i], val) == 0) {
+		bool matched;
+		if (a->syntax->operator_fn) {
+			ret = a->syntax->operator_fn(ldb, LDB_OP_EQUALITY, a,
+						     &el->values[i], val, &matched);
+			if (ret != LDB_SUCCESS) return ret;
+		} else {
+			matched = (a->syntax->comparison_fn(ldb, ldb,
+							    &el->values[i], val) == 0);
+		}
+		if (matched) {
 			if (el->num_values == 1) {
 				return msg_delete_attribute(module, ldb, msg, name);
 			}
diff --git a/source4/lib/ldb/modules/rdn_name.c b/source4/lib/ldb/modules/rdn_name.c
index 5dc122f254..a0867c0f51 100644
--- a/source4/lib/ldb/modules/rdn_name.c
+++ b/source4/lib/ldb/modules/rdn_name.c
@@ -147,9 +147,16 @@ static int rdn_name_add(struct ldb_module *module, struct ldb_request *req)
 		}
 		/* normalise attribute value */
 		for (i = 0; i < attribute->num_values; i++) {
-			ret = a->syntax->comparison_fn(ldb, msg,
-					&rdn_val, &attribute->values[i]);
-			if (ret == 0) {
+			bool matched;
+			if (a->syntax->operator_fn) {
+				ret = a->syntax->operator_fn(ldb, LDB_OP_EQUALITY, a,
+							     &rdn_val, &attribute->values[i], &matched);
+				if (ret != LDB_SUCCESS) return ret;
+			} else {
+				matched = (a->syntax->comparison_fn(ldb, msg,
+								    &rdn_val, &attribute->values[i]) == 0);
+			}
+			if (matched) {
 				/* overwrite so it matches in case */
 				attribute->values[i] = rdn_val;
 				break;