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mariadb/scripts/sys_schema/functions/sys_get_config.sql
Oleksandr Byelkin 6c951fea5f MDEV-39993 Use CREATE OR REPLACE for sys schema routines
mariadb-upgrade silently dropped EXECUTE grants on sys schema stored
functions and procedures. The sys schema install scripts reinstalled
every routine with DROP FUNCTION/PROCEDURE IF EXISTS followed by
CREATE. DROP cascades to delete the routine's rows in
mysql.procs_priv, so any EXECUTE grant a DBA had issued on e.g.
sys.table_exists or sys.quote_identifier was lost every time
mariadb-upgrade reinstalled the sys schema, even though the routine
itself came back unchanged.

Fix: replace DROP ... IF EXISTS + CREATE with CREATE OR REPLACE in
all 53 sys_schema function/procedure files and in the two templates
(templates/function.sql, templates/procedure.sql) so future routines
follow the same pattern. CREATE OR REPLACE PROCEDURE/FUNCTION goes
through sp_drop_routine_internal(), which only deletes the
mysql.proc row and never reaches sp_revoke_privileges() (that is
only called from the explicit DROP PROCEDURE/FUNCTION statement),
so mysql.procs_priv is left untouched and existing grants survive.
This mirrors the pattern already used by sys schema views
(CREATE OR REPLACE ... VIEW, since MDEV-9077), which never had this
problem.

Four of the converted files (functions/format_path.sql,
functions/ps_is_account_enabled_57.sql,
procedures/ps_setup_reset_to_default.sql,
procedures/ps_trace_thread_57.sql) are not referenced by
scripts/sys_schema/CMakeLists.txt; they were converted anyway for
consistency and have no behavioural effect.

As a side effect, a pre-existing UDF whose name collides with a sys
routine name is no longer destroyed before the reinstall fails:
DROP FUNCTION IF EXISTS resolved the UDF namespace first, silently
dropping the UDF and then failing on ER_SP_ALREADY_EXISTS anyway;
CREATE OR REPLACE fails immediately on ER_UDF_EXISTS with the UDF
intact.

scripts/maria_add_gis_sp.sql.in and the sys_config triggers were
deliberately left untouched: the GIS procedures are only
re-installed at bootstrap time (mariadb-upgrade instead patches
their definer in place via UPDATE), and triggers carry no
procs_priv rows, so neither is on the code path this bug is about.

Added mysql-test/main/mysql_upgrade_sys_routine_grants.test, which
grants EXECUTE on sys.table_exists and sys.quote_identifier,
overwrites both routine bodies with a marker to prove the upgrade
actually reinstalls them (rather than the sys schema install being
skipped), runs mariadb-upgrade, and checks both that the grants
survived and that the real routine bodies came back.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-09-21 17:07:02 +02:00

98 lines
4.1 KiB
SQL

-- Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation; version 2 of the License.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
DELIMITER $$
CREATE OR REPLACE DEFINER='mariadb.sys'@'localhost' FUNCTION sys_get_config (
in_variable_name VARCHAR(128),
in_default_value VARCHAR(128)
)
RETURNS VARCHAR(128)
COMMENT '
Description
-----------
Returns the value for the requested variable using the following logic:
1. If the option exists in sys.sys_config return the value from there.
2. Else fall back on the provided default value.
Notes for using sys_get_config():
* If the default value argument to sys_get_config() is NULL and case 2. is reached, NULL is returned.
It is then expected that the caller is able to handle NULL for the given configuration option.
* The convention is to name the user variables @sys.<name of variable>. It is <name of variable> that
is stored in the sys_config table and is what is expected as the argument to sys_get_config().
* If you want to check whether the configuration option has already been set and if not assign with
the return value of sys_get_config() you can use IFNULL(...) (see example below). However this should
not be done inside a loop (e.g. for each row in a result set) as for repeated calls where assignment
is only needed in the first iteration using IFNULL(...) is expected to be significantly slower than
using an IF (...) THEN ... END IF; block (see example below).
Parameters
-----------
in_variable_name (VARCHAR(128)):
The name of the config option to return the value for.
in_default_value (VARCHAR(128)):
The default value to return if the variable does not exist in sys.sys_config.
Returns
-----------
VARCHAR(128)
Example
-----------
-- Get the configuration value from sys.sys_config falling back on 128 if the option is not present in the table.
mysql> SELECT sys.sys_get_config(''statement_truncate_len'', 128) AS Value;
+-------+
| Value |
+-------+
| 64 |
+-------+
1 row in set (0.00 sec)
-- Check whether the option is already set, if not assign - IFNULL(...) one liner example.
mysql> SET @sys.statement_truncate_len = IFNULL(@sys.statement_truncate_len, sys.sys_get_config(''statement_truncate_len'', 64));
Query OK, 0 rows affected (0.00 sec)
-- Check whether the option is already set, if not assign - IF ... THEN ... END IF example.
IF (@sys.statement_truncate_len IS NULL) THEN
SET @sys.statement_truncate_len = sys.sys_get_config(''statement_truncate_len'', 64);
END IF;
'
SQL SECURITY INVOKER
DETERMINISTIC
READS SQL DATA
BEGIN
DECLARE v_value VARCHAR(128) DEFAULT NULL;
DECLARE old_val INTEGER DEFAULT NULL;
-- Check if we have the variable in the sys.sys_config table
SET v_value = (SELECT value FROM sys.sys_config WHERE variable = in_variable_name);
-- Protection against the variable not existing in sys_config
IF (v_value IS NULL) THEN
SET v_value = in_default_value;
END IF;
RETURN v_value;
END $$
DELIMITER ;