s4:dsdb_sort_objectClass_attr - simplify memory context handling

Do only require the out memory context and build the temporary one in
the body of the function. This greatly simplifies the callers.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>

3 files changed, 23 insertions, 37 deletions

diff --git a/source4/dsdb/pydsdb.c b/source4/dsdb/pydsdb.c
index 39229f487f5..99e239e60c8 100644
--- a/source4/dsdb/pydsdb.c
+++ b/source4/dsdb/pydsdb.c
@@ -681,8 +681,7 @@ static PyObject *py_dsdb_normalise_attributes(PyObject *self, PyObject *args)
 	/* Normalise "objectClass" attribute if needed */
 	if (ldb_attr_cmp(a->lDAPDisplayName, "objectClass") == 0) {
 		int iret;
-		iret = dsdb_sort_objectClass_attr(ldb, schema, tmp_ctx, el,
-						 tmp_ctx, el);
+		iret = dsdb_sort_objectClass_attr(ldb, schema, el, tmp_ctx, el);
 		if (iret != LDB_SUCCESS) {
 			PyErr_SetString(PyExc_RuntimeError, ldb_errstring(ldb));
 			talloc_free(tmp_ctx);
diff --git a/source4/dsdb/samdb/ldb_modules/objectclass.c b/source4/dsdb/samdb/ldb_modules/objectclass.c
index 7d34b4e8c3b..074360086f9 100644
--- a/source4/dsdb/samdb/ldb_modules/objectclass.c
+++ b/source4/dsdb/samdb/ldb_modules/objectclass.c
@@ -383,7 +383,6 @@ static int objectclass_do_add(struct oc_context *ac)
 	struct ldb_request *add_req;
 	struct ldb_message_element *objectclass_element, *el;
 	struct ldb_message *msg;
-	TALLOC_CTX *mem_ctx;
 	const char *rdn_name = NULL;
 	char *value;
 	const struct dsdb_class *objectclass;
@@ -448,22 +447,14 @@ static int objectclass_do_add(struct oc_context *ac)
 			return LDB_ERR_CONSTRAINT_VIOLATION;
 		}
 
-		mem_ctx = talloc_new(ac);
-		if (mem_ctx == NULL) {
-			return ldb_module_oom(ac->module);
-		}
-
 		/* Now do the sorting */
-		ret = dsdb_sort_objectClass_attr(ldb, ac->schema, mem_ctx,
+		ret = dsdb_sort_objectClass_attr(ldb, ac->schema,
 						 objectclass_element, msg,
 						 objectclass_element);
 		if (ret != LDB_SUCCESS) {
-			talloc_free(mem_ctx);
 			return ret;
 		}
 
-		talloc_free(mem_ctx);
-
 		/*
 		 * Get the new top-most structural object class and check for
 		 * unrelated structural classes
@@ -823,7 +814,6 @@ static int objectclass_do_mod(struct oc_context *ac)
 	struct ldb_message_element *oc_el_entry, *oc_el_change;
 	struct ldb_val *vals;
 	struct ldb_message *msg;
-	TALLOC_CTX *mem_ctx;
 	const struct dsdb_class *objectclass;
 	unsigned int i, j, k;
 	bool found;
@@ -851,11 +841,6 @@ static int objectclass_do_mod(struct oc_context *ac)
 
 	msg->dn = ac->req->op.mod.message->dn;
 
-	mem_ctx = talloc_new(ac);
-	if (mem_ctx == NULL) {
-		return ldb_module_oom(ac->module);
-	}
-
 	/* We've to walk over all "objectClass" message elements */
 	for (k = 0; k < ac->req->op.mod.message->num_elements; k++) {
 		if (ldb_attr_cmp(ac->req->op.mod.message->elements[k].name,
@@ -876,7 +861,6 @@ static int objectclass_do_mod(struct oc_context *ac)
 								       "objectclass: cannot re-add an existing objectclass: '%.*s'!",
 								       (int)oc_el_change->values[i].length,
 								       (const char *)oc_el_change->values[i].data);
-						talloc_free(mem_ctx);
 						return LDB_ERR_ATTRIBUTE_OR_VALUE_EXISTS;
 					}
 				}
@@ -886,7 +870,6 @@ static int objectclass_do_mod(struct oc_context *ac)
 						      struct ldb_val,
 						      oc_el_entry->num_values + 1);
 				if (vals == NULL) {
-					talloc_free(mem_ctx);
 					return ldb_module_oom(ac->module);
 				}
 				oc_el_entry->values = vals;
@@ -933,7 +916,6 @@ static int objectclass_do_mod(struct oc_context *ac)
 							       "objectclass: cannot delete this objectclass: '%.*s'!",
 							       (int)oc_el_change->values[i].length,
 							       (const char *)oc_el_change->values[i].data);
-					talloc_free(mem_ctx);
 					return LDB_ERR_NO_SUCH_ATTRIBUTE;
 				}
 			}
@@ -942,10 +924,9 @@ static int objectclass_do_mod(struct oc_context *ac)
 		}
 
 		/* Now do the sorting */
-		ret = dsdb_sort_objectClass_attr(ldb, ac->schema, mem_ctx,
-						 oc_el_entry, msg, oc_el_entry);
+		ret = dsdb_sort_objectClass_attr(ldb, ac->schema, oc_el_entry,
+						 msg, oc_el_entry);
 		if (ret != LDB_SUCCESS) {
-			talloc_free(mem_ctx);
 			return ret;
 		}
 
@@ -958,7 +939,6 @@ static int objectclass_do_mod(struct oc_context *ac)
 		if (objectclass == NULL) {
 			ldb_set_errstring(ldb,
 					  "objectclass: cannot delete all structural objectclasses!");
-			talloc_free(mem_ctx);
 			return LDB_ERR_OBJECT_CLASS_VIOLATION;
 		}
 
@@ -967,13 +947,10 @@ static int objectclass_do_mod(struct oc_context *ac)
 						    objectclass,
 						    oc_el_entry);
 		if (ret != LDB_SUCCESS) {
-			talloc_free(mem_ctx);
 			return ret;
 		}
 	}
 
-	talloc_free(mem_ctx);
-
 	/* Now add the new object class attribute to the change message */
 	ret = ldb_msg_add(msg, oc_el_entry, LDB_FLAG_MOD_REPLACE);
 	if (ret != LDB_SUCCESS) {
diff --git a/source4/dsdb/schema/schema_query.c b/source4/dsdb/schema/schema_query.c
index ce46fa63156..013878d1f19 100644
--- a/source4/dsdb/schema/schema_query.c
+++ b/source4/dsdb/schema/schema_query.c
@@ -451,14 +451,12 @@ const struct GUID *attribute_schemaid_guid_by_lDAPDisplayName(const struct dsdb_
  * into correct order and validate that all object classes specified actually
  * exist in the schema.
  * The output is written in an existing LDB message element
- * "out_objectclass_element" where the values will be allocated on
- * "out_mem_ctx".
+ * "out_objectclass_element" where the values will be allocated on "mem_ctx".
  */
 int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 			       const struct dsdb_schema *schema,
-			       TALLOC_CTX *mem_ctx,
 			       const struct ldb_message_element *objectclass_element,
-			       TALLOC_CTX *out_mem_ctx,
+			       TALLOC_CTX *mem_ctx,
 			       struct ldb_message_element *out_objectclass_element)
 {
 	unsigned int i, lowest;
@@ -469,6 +467,12 @@ int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 	  *poss_parent = NULL, *new_parent = NULL,
 	  *current_lowest = NULL, *current_lowest_struct = NULL;
 	struct ldb_message_element *el;
+	TALLOC_CTX *tmp_mem_ctx;
+
+	tmp_mem_ctx = talloc_new(mem_ctx);
+	if (tmp_mem_ctx == NULL) {
+		return ldb_oom(ldb);
+	}
 
 	/*
 	 * DESIGN:
@@ -504,8 +508,9 @@ int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 	 * except for 'top', which is special
 	 */
 	for (i=0; i < objectclass_element->num_values; i++) {
-		current = talloc(mem_ctx, struct class_list);
+		current = talloc(tmp_mem_ctx, struct class_list);
 		if (!current) {
+			talloc_free(tmp_mem_ctx);
 			return ldb_oom(ldb);
 		}
 		current->objectclass = dsdb_class_by_lDAPDisplayName_ldb_val(schema, &objectclass_element->values[i]);
@@ -513,11 +518,13 @@ int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 			ldb_asprintf_errstring(ldb, "objectclass %.*s is not a valid objectClass in schema",
 					       (int)objectclass_element->values[i].length, (const char *)objectclass_element->values[i].data);
 			/* This looks weird, but windows apparently returns this for invalid objectClass values */
+			talloc_free(tmp_mem_ctx);
 			return LDB_ERR_NO_SUCH_ATTRIBUTE;
 		} else if (current->objectclass->isDefunct) {
 			ldb_asprintf_errstring(ldb, "objectclass %.*s marked as isDefunct objectClass in schema - not valid for new objects",
 					       (int)objectclass_element->values[i].length, (const char *)objectclass_element->values[i].data);
 			/* This looks weird, but windows apparently returns this for invalid objectClass values */
+			talloc_free(tmp_mem_ctx);
 			return LDB_ERR_NO_SUCH_ATTRIBUTE;
 		}
 
@@ -529,7 +536,7 @@ int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 
 
 	/* Add top here, to prevent duplicates */
-	current = talloc(mem_ctx, struct class_list);
+	current = talloc(tmp_mem_ctx, struct class_list);
 	current->objectclass = dsdb_class_by_lDAPDisplayName(schema, "top");
 	DLIST_ADD_END(sorted, current, struct class_list *);
 
@@ -545,7 +552,7 @@ int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 			continue;
 		}
 
-		new_parent = talloc(mem_ctx, struct class_list);
+		new_parent = talloc(tmp_mem_ctx, struct class_list);
 		new_parent->objectclass = dsdb_class_by_lDAPDisplayName(schema, current->objectclass->subClassOf);
 		DLIST_ADD_END(unsorted, new_parent, struct class_list *);
 	}
@@ -583,16 +590,18 @@ int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 	el = out_objectclass_element;
 
 	el->flags = objectclass_element->flags;
-	el->name = talloc_strdup(out_mem_ctx, objectclass_element->name);
+	el->name = talloc_strdup(mem_ctx, objectclass_element->name);
 	if (el->name == NULL) {
+		talloc_free(tmp_mem_ctx);
 		return ldb_oom(ldb);
 	}
 	el->num_values = 0;
 	el->values = NULL;
 	for (current = sorted; current != NULL; current = current->next) {
-		el->values = talloc_realloc(out_mem_ctx, el->values,
+		el->values = talloc_realloc(mem_ctx, el->values,
 					    struct ldb_val, el->num_values + 1);
 		if (el->values == NULL) {
+			talloc_free(tmp_mem_ctx);
 			return ldb_oom(ldb);
 		}
 		el->values[el->num_values] = data_blob_string_const(current->objectclass->lDAPDisplayName);
@@ -600,5 +609,6 @@ int dsdb_sort_objectClass_attr(struct ldb_context *ldb,
 		++(el->num_values);
 	}
 
+	talloc_free(tmp_mem_ctx);
 	return LDB_SUCCESS;
 }