Function mysql_drop_function

sql/sql_udf.cc:659–740

enum drop_udf_result mysql_drop_function(THD *thd, const LEX_CSTRING *udf_name)
{
  TABLE *table;
  udf_func *udf;
  DBUG_ENTER("mysql_drop_function");

  if (thd->locked_tables_mode)
  {
    my_error(ER_LOCK_OR_ACTIVE_TRANSACTION, MYF(0));
    DBUG_RETURN(UDF_DEL_RESULT_ERROR);
  }

  if (!(table= open_udf_func_table(thd)))
    DBUG_RETURN(UDF_DEL_RESULT_ERROR);

  // Fast pre-check
  if (!mysql_rwlock_tryrdlock(&THR_LOCK_udf))
  {
    bool found= find_udf_everywhere(thd, *udf_name, table);
    mysql_rwlock_unlock(&THR_LOCK_udf);
    if (!found)
    {
      close_mysql_tables(thd);
      DBUG_RETURN(UDF_DEL_RESULT_ABSENT);
    }
  }

  if (!initialized)
  {
    close_mysql_tables(thd);
    if (opt_noacl)
      DBUG_RETURN(UDF_DEL_RESULT_ABSENT); // SP should be checked

    my_message(ER_OUT_OF_RESOURCES, ER_THD(thd, ER_OUT_OF_RESOURCES), MYF(0));
    DBUG_RETURN(UDF_DEL_RESULT_ERROR);
  }

  mysql_rwlock_wrlock(&THR_LOCK_udf);

  // re-check under protection
  if (!find_udf_everywhere(thd, *udf_name, table))
  {
    close_mysql_tables(thd);
    mysql_rwlock_unlock(&THR_LOCK_udf);
    DBUG_RETURN(UDF_DEL_RESULT_ABSENT);
  }

  if (check_access(thd, DELETE_ACL, "mysql", NULL, NULL, 1, 0))
    goto err;


  DEBUG_SYNC(current_thd, "mysql_drop_function_after_lock");

  if (!(udf= (udf_func*) my_hash_search(&udf_hash, (uchar*) udf_name->str,
                                        (uint) udf_name->length)) )
  {
    if (remove_udf_in_table(*udf_name, table))
      goto err;