dns scavenging: simplify copy_current_records

We don't need to pull and push to make a byte identical copy of an ldb
value, nor do we need a temporary array.

As part of this, we avoid leaving a dangling el->num_values pointing
into space where there were no actually allocated values, which is not
how we do things, even briefly.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

diff --git a/source4/dsdb/kcc/scavenge_dns_records.c b/source4/dsdb/kcc/scavenge_dns_records.c
index b9564a5d6f6eeb44667a205d4ffbef6f04d87a73..6084808ca34c810b6481f1477c54bc90b2c24b5b 100644 (file)
--- a/source4/dsdb/kcc/scavenge_dns_records.c
+++ b/source4/dsdb/kcc/scavenge_dns_records.c
@@ -48,64 +48,33 @@ static NTSTATUS copy_current_records(TALLOC_CTX *mem_ctx,
                                     struct ldb_message_element *el,
                                     uint32_t dns_timestamp)
 {
-       unsigned int i, num_kept = 0;
-       struct dnsp_DnssrvRpcRecord *recs = NULL;
+       unsigned int i;
+       struct dnsp_DnssrvRpcRecord rec;
        enum ndr_err_code ndr_err;
-       TALLOC_CTX *tmp_ctx = talloc_new(NULL);
-
-       if (tmp_ctx == NULL) {
-               return NT_STATUS_NO_MEMORY;
-       }
 
-       recs = talloc_zero_array(
-           tmp_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
-       if (recs == NULL) {
-               TALLOC_FREE(tmp_ctx);
+       el->values = talloc_zero_array(mem_ctx, struct ldb_val,
+                                      old_el->num_values);
+       if (el->values == NULL) {
                return NT_STATUS_NO_MEMORY;
        }
 
-       for (i = 0; i < el->num_values; i++) {
+       for (i = 0; i < old_el->num_values; i++) {
                ndr_err = ndr_pull_struct_blob(
                    &(old_el->values[i]),
-                   tmp_ctx,
-                   &(recs[num_kept]),
+                   mem_ctx,
+                   &rec,
                    (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
                if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
-                       TALLOC_FREE(tmp_ctx);
                        DBG_ERR("Failed to pull dns rec blob.\n");
                        return NT_STATUS_INTERNAL_ERROR;
                }
-               if (recs[num_kept].dwTimeStamp > dns_timestamp ||
-                   recs[num_kept].dwTimeStamp == 0) {
-                       num_kept++;
-               }
-       }
-
-       if (num_kept == el->num_values) {
-               TALLOC_FREE(tmp_ctx);
-               return NT_STATUS_OK;
-       }
-
-       el->values = talloc_zero_array(mem_ctx, struct ldb_val, num_kept);
-       if (el->values == NULL) {
-               TALLOC_FREE(tmp_ctx);
-               return NT_STATUS_NO_MEMORY;
-       }
-       el->num_values = num_kept;
-       for (i = 0; i < el->num_values; i++) {
-               ndr_err = ndr_push_struct_blob(
-                   &(el->values[i]),
-                   mem_ctx,
-                   &(recs[i]),
-                   (ndr_push_flags_fn_t)ndr_push_dnsp_DnssrvRpcRecord);
-               if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
-                       TALLOC_FREE(tmp_ctx);
-                       DBG_ERR("Failed to push dnsp_DnssrvRpcRecord\n");
-                       return NT_STATUS_INTERNAL_ERROR;
+               if (rec.dwTimeStamp > dns_timestamp ||
+                   rec.dwTimeStamp == 0) {
+                       el->values[el->num_values] = old_el->values[i];
+                       el->num_values++;
                }
        }
 
-       TALLOC_FREE(tmp_ctx);
        return NT_STATUS_OK;
 }
 
@@ -235,7 +204,6 @@ static NTSTATUS dns_tombstone_records_zone(TALLOC_CTX *mem_ctx,
                        return NT_STATUS_INTERNAL_ERROR;
                }
 
-               el->num_values = old_el->num_values;
                status = copy_current_records(mem_ctx, old_el, el, dns_timestamp);
 
                if (!NT_STATUS_IS_OK(status)) {