s4-ldb: much more memory efficient msg filtering

this ensures we don't leave unnecessary attributes in returned ldb
objects

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

diff --git a/source4/lib/ldb/ldb_tdb/ldb_search.c b/source4/lib/ldb/ldb_tdb/ldb_search.c
index ca47fa3a5dabb686213df6adddc38824b567c49e..5df1e4d59e6c4a61b5df567cab31c00e55a93b86 100644 (file)
--- a/source4/lib/ldb/ldb_tdb/ldb_search.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_search.c
@@ -329,6 +329,8 @@ int ltdb_filter_attrs(struct ldb_message *msg, const char * const *attrs)
 {
        unsigned int i;
        int keep_all = 0;
+       struct ldb_message_element *el2;
+       uint32_t num_elements;
 
        if (attrs) {
                /* check for special attrs */
@@ -355,6 +357,12 @@ int ltdb_filter_attrs(struct ldb_message *msg, const char * const *attrs)
                return 0;
        }
 
+       el2 = talloc_array(msg, struct ldb_message_element, msg->num_elements);
+       if (el2 == NULL) {
+               return -1;
+       }
+       num_elements = 0;
+
        for (i = 0; i < msg->num_elements; i++) {
                unsigned int j;
                int found = 0;
@@ -366,12 +374,21 @@ int ltdb_filter_attrs(struct ldb_message *msg, const char * const *attrs)
                        }
                }
 
-               if (!found) {
-                       ldb_msg_remove_attr(msg, msg->elements[i].name);
-                       i--;
+               if (found) {
+                       el2[num_elements] = msg->elements[i];
+                       talloc_steal(el2, el2[num_elements].name);
+                       talloc_steal(el2, el2[num_elements].values);
+                       num_elements++;
                }
        }
 
+       talloc_free(msg->elements);
+       msg->elements = talloc_realloc(msg, el2, struct ldb_message_element, msg->num_elements);
+       if (msg->elements == NULL) {
+               return -1;
+       }
+       msg->num_elements = num_elements;
+
        return 0;
 }