Fix for bug #12280 "Triggers: crash if flush tables".

We should not allow FLUSH statement to be executed inside both triggers
and stored functions.

mysql-test/r/sp-error.result

@@ -247,7 +247,7 @@ end|
 ERROR 42000: Duplicate cursor: c
 create procedure u()
 use sptmp|
-ERROR 42000: USE is not allowed in a stored procedure
+ERROR 0A000: USE is not allowed in stored procedures
 create procedure p()
 begin
 declare c cursor for select * from t1;
@@ -616,7 +616,7 @@ begin
 flush tables;
 return 5;
 end|
-ERROR 0A000: FLUSH is not allowed in stored procedures
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
 create procedure bug9529_90123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123()
 begin
 end|

mysql-test/r/trigger.result

@@ -2,6 +2,7 @@ drop table if exists t1, t2, t3;
 drop view if exists v1;
 drop database if exists mysqltest;
 drop function if exists f1;
+drop procedure if exists p1;
 create table t1 (i int);
 create trigger trg before insert on t1 for each row set @a:=1;
 set @a:=0;
@@ -635,3 +636,18 @@ show triggers;
 Trigger	Event	Table	Statement	Timing	Created	sql_mode
 t1_bi	INSERT	t1	 set new.a = '2004-01-00'	BEFORE	#	
 drop table t1;
+create table t1 (id int);
+create trigger t1_ai after insert on t1 for each row flush tables;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush privileges;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create procedure p1() flush tables;
+create trigger t1_ai after insert on t1 for each row call p1();
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush privileges;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+drop table t1;

mysql-test/t/sp-error.test

@@ -334,7 +334,7 @@ begin
 end|
 
 # USE is not allowed
---error 1336
+--error ER_SP_BADSTATEMENT 
 create procedure u()
   use sptmp|
 
@@ -885,7 +885,7 @@ create procedure bug10537()
 --disable_warnings
 drop function if exists bug8409|
 --enable_warnings
---error ER_SP_BADSTATEMENT
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
 create function bug8409()
   returns int
 begin

mysql-test/t/trigger.test

@@ -7,6 +7,7 @@ drop table if exists t1, t2, t3;
 drop view if exists v1;
 drop database if exists mysqltest;
 drop function if exists f1;
+drop procedure if exists p1;
 --enable_warnings
 
 create table t1 (i int);
@@ -642,3 +643,22 @@ show create table t1;
 --replace_column 6 #
 show triggers;
 drop table t1;
+
+# Test for bug #12280 "Triggers: crash if flush tables"
+# FLUSH TABLES and FLUSH PRIVILEGES should be disallowed inside
+# of functions and triggers.
+create table t1 (id int);
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush tables;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush privileges;
+create procedure p1() flush tables;
+create trigger t1_ai after insert on t1 for each row call p1();
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+drop procedure p1;
+create procedure p1() flush privileges;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+drop procedure p1;
+drop table t1;

sql/share/errmsg.txt

@@ -5137,8 +5137,8 @@ ER_SP_CANT_ALTER
 	eng "Failed to ALTER %s %s"
 ER_SP_SUBSELECT_NYI 0A000 
 	eng "Subselect value not supported"
-ER_SP_NO_USE 42000 
-	eng "USE is not allowed in a stored procedure"
+ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG 0A000
+        eng "%s is not allowed in stored function or trigger"
 ER_SP_VARCOND_AFTER_CURSHNDLR 42000 
 	eng "Variable or condition declaration after cursor or handler declaration"
 ER_SP_CURSOR_AFTER_HANDLER 42000 

sql/sql_parse.cc

@@ -6395,6 +6395,13 @@ bool reload_acl_and_cache(THD *thd, ulong options, TABLE_LIST *tables,
   bool result=0;
   select_errors=0;				/* Write if more errors */
   bool tmp_write_to_binlog= 1;
+
+  if (thd->in_sub_stmt)
+  {
+    my_error(ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG, MYF(0), "FLUSH");
+    return 1;
+  }
+
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   if (options & REFRESH_GRANT)
   {

sql/sql_yacc.yy

@@ -1960,7 +1960,7 @@ sp_proc_stmt:
 	    }
 	    if (lex->sql_command == SQLCOM_CHANGE_DB)
 	    { /* "USE db" doesn't work in a procedure */
-	      my_message(ER_SP_NO_USE, ER(ER_SP_NO_USE), MYF(0));
+	      my_error(ER_SP_BADSTATEMENT, MYF(0), "USE");
 	      YYABORT;
 	    }
 	    /*
@@ -6642,9 +6642,14 @@ flush:
 	FLUSH_SYM opt_no_write_to_binlog
 	{
 	  LEX *lex=Lex;
-	  if (lex->sphead && lex->sphead->m_type == TYPE_ENUM_FUNCTION)
+	  if (lex->sphead && lex->sphead->m_type != TYPE_ENUM_PROCEDURE)
 	  {
-	    my_error(ER_SP_BADSTATEMENT, MYF(0), "FLUSH");
+            /*
+              Note that both FLUSH TABLES and FLUSH PRIVILEGES will break
+              execution in prelocked mode. So it is better to disable
+              FLUSH in stored functions and triggers completely.
+            */
+            my_error(ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG, MYF(0), "FLUSH");
 	    YYABORT;
 	  }
 	  lex->sql_command= SQLCOM_FLUSH; lex->type=0;