What happens in procedures stays in procedures

Impossible is nothing

DELIMITER //
 CREATE PROCEDURE show_processlist()
 BEGIN
 show processlist;
 END //
 DELIMITER ;
 

$ mysql -u root -p
 Enter password:
 Welcome to the MySQL monitor. Commands end with ; or \g.
 Your MySQL connection id is 112
 Server version: 5.7.17 MySQL Community Server (GPL)
 
 Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
 
 Oracle is a registered trademark of Oracle Corporation and/or its
 affiliates. Other names may be trademarks of their respective
 owners.
 
 Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
 mysql> CREATE DATABASE pythian;
 mysql> USE pythian;
 mysql> DELIMITER //
 mysql> CREATE PROCEDURE show_processlist()
  -> BEGIN
  -> show processlist;
  -> END //
 Query OK, 0 rows affected (0,00 sec)
 
 mysql> DELIMITER ;
 mysql> CREATE USER test_user@'%' identified by 'test';
 Query OK, 0 rows affected (0,01 sec)
 mysql> GRANT EXECUTE ON PROCEDURE pythian.show_processlist TO test_user;
 Query OK, 0 rows affected (0,00 sec)
 
 mysql> exit
 

$ mysql -s -u test_user -ptest pythian
 mysql: [Warning] Using a password on the command line interface can be insecure.
 mysql> call show_processlist;
 Id User Host db Command Time State Info
 112 root localhost pythian Sleep 3 NULL
 116 root localhost pythian Query 0 checking permissions show processlist
 mysql>
 mysql> show grants for current_user();
 Grants for test_user@%
 GRANT USAGE ON *.* TO 'test_user'@'%'
 GRANT EXECUTE ON PROCEDURE `pythian`.`show_processlist` TO 'test_user'@'%'
 mysql>
 

Preparation is the key to success

DELIMITER //
 CREATE PROCEDURE pythian.change_master(newmaster varchar(256))
 BEGIN
 SET @change_master=CONCAT('CHANGE MASTER TO MASTER_HOST=\'',newmaster,'\'');
 PREPARE cmtm FROM @change_master;
 SET sql_log_bin=FALSE;
 EXECUTE cmtm;
 DEALLOCATE PREPARE cmtm;
 SET sql_log_bin=TRUE;
 END //
 CREATE PROCEDURE show_slave_status()
 BEGIN
 show slave status;
 END //
 DELIMITER ;
 GRANT EXECUTE ON PROCEDURE pythian.change_master TO test_user;
 GRANT EXECUTE ON PROCEDURE pythian.show_slave_status TO test_user;
 

mysql> call pythian.show_slave_status;
 mysql> call pythian.change_master('master2');
 mysql> call show_slave_status\G
 *************************** 1. row ***************************
  Slave_IO_State:
  Master_Host: master2
  Master_User:
  Master_Port: 3306
  Connect_Retry: 60
  Master_Log_File:
  Read_Master_Log_Pos: 4
  Relay_Log_File: iMac-de-Pep-relay-bin.000001
  Relay_Log_Pos: 4
  Relay_Master_Log_File:
  Slave_IO_Running: No
  Slave_SQL_Running: No
  Replicate_Do_DB:
  Replicate_Ignore_DB:
  Replicate_Do_Table:
  Replicate_Ignore_Table:
  Replicate_Wild_Do_Table:
  Replicate_Wild_Ignore_Table:
  Last_Errno: 0
  Last_Error:
  Skip_Counter: 0
  Exec_Master_Log_Pos: 0
  Relay_Log_Space: 154
  Until_Condition: None
  Until_Log_File:
  Until_Log_Pos: 0
  Master_SSL_Allowed: No
  Master_SSL_CA_File:
  Master_SSL_CA_Path:
  Master_SSL_Cert:
  Master_SSL_Cipher:
  Master_SSL_Key:
  Seconds_Behind_Master: NULL
 Master_SSL_Verify_Server_Cert: No
  Last_IO_Errno: 0
  Last_IO_Error:
  Last_SQL_Errno: 0
  Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
  Master_Server_Id: 0
  Master_UUID:
  Master_Info_File: /opt/mysql/data/master.info
  SQL_Delay: 0
  SQL_Remaining_Delay: NULL
  Slave_SQL_Running_State:
  Master_Retry_Count: 86400
  Master_Bind:
  Last_IO_Error_Timestamp:
  Last_SQL_Error_Timestamp:
  Master_SSL_Crl:
  Master_SSL_Crlpath:
  Retrieved_Gtid_Set:
  Executed_Gtid_Set:
  Auto_Position: 0
  Replicate_Rewrite_DB:
  Channel_Name:
  Master_TLS_Version:
 

Security first