ITS#7256 A few issues discovered during testing slapmodify.

- bdb deallocates cursor after some tool operations but expects it to be
  around every time it is called
- mdb tries to allocate a second transaction while it already holds one,
  deadlocking
- op->o_hdr must exist for most uses of op, but o_tmpmfuncs need not
- what about indexing after a tool modify? Does it happen automatically?

servers/slapd/back-bdb/tools.c

@@ -747,6 +747,15 @@ done:
 		e->e_id = NOID;
 	}
 
+	if ( cursor == NULL )
+	{
+		int rc = bdb->bi_id2entry->bdi_db->cursor(
+			bdb->bi_id2entry->bdi_db, bdb->bi_cache.c_txn, &cursor,
+			bdb->bi_db_opflags );
+		if ( rc != 0 )
+			e->e_id = NOID;
+	}
+
 	return e->e_id;
 }
 
@@ -982,6 +991,15 @@ done:
 		e->e_id = NOID;
 	}
 
+	if ( cursor == NULL )
+	{
+		int rc = bdb->bi_id2entry->bdi_db->cursor(
+			bdb->bi_id2entry->bdi_db, bdb->bi_cache.c_txn, &cursor,
+			bdb->bi_db_opflags );
+		if ( rc != 0 )
+			e->e_id = NOID;
+	}
+
 	return e->e_id;
 }
 

servers/slapd/back-mdb/id2entry.c

@@ -245,7 +245,7 @@ int mdb_entry_return(
 	if ( !e )
 		return 0;
 	if ( e->e_private ) {
-		if ( op->o_hdr ) {
+		if ( op->o_hdr && op->o_tmpmfuncs ) {
 			op->o_tmpfree( e->e_nname.bv_val, op->o_tmpmemctx );
 			op->o_tmpfree( e->e_name.bv_val, op->o_tmpmemctx );
 			op->o_tmpfree( e, op->o_tmpmemctx );