Fix for bug#21795: SP: sp_head::is_not_allowed_in_function() contains

erroneous check

Problem: Actually there were two problems in the server code. The check
for SQLCOM_FLUSH in SF/Triggers were not according to the existing
architecture which uses sp_get_flags_for_command() from sp_head.cc .
This function was also missing a check for SQLCOM_FLUSH which has a
problem combined with prelocking. This changeset fixes both of these
deficiencies as well as the erroneous check in
sp_head::is_not_allowed_in_function() which was a copy&paste error.


mysql-test/r/sp-error.result:
  update result
mysql-test/r/trigger.result:
  update result
mysql-test/t/sp-error.test:
  FLUSH can create a problem with prelocking, hence it's disabled.
  There is a better way to check this than a check in the parser.
  Now we use sp_get_flags_for_command() and the error returned is
  different.
mysql-test/t/trigger.test:
  FLUSH can create a problem with prelocking, hence it's disabled.
  There is a better way to check this than a check in the parser.
  Now we use sp_get_flags_for_command() and the error returned is
  different.
sql/sp_head.cc:
  FLUSH and RESET are not allowed inside a SF/Trigger.
  Because they don't imply a COMMIT sp_head::HAS_COMMIT_OR_ROLLBACK
  cannot be used. Two new flags were introduced for that reason.
sql/sp_head.h:
  Don't check m_type as this check is erroneous. This is probably
  a copy and paste error when moving code from somewhere else. Another
  fact which supports this was prefixing the enum value with the name
  of class sp_head.
  
  Adding two new flags HAS_SQLCOM_RESET and HAS_SQLCOM_FLUSH. The values
  are 2048 and 4096 because in the 5.1 branch there are already new flags
  which are with values up-to 1024.
sql/sql_parse.cc:
  FLUSH can cause a problem with prelocking in SF/Trigger and
  therefore is already disabled. RESET is also disabled because
  is handled by the same code as FLUSH. We won't allow RESET inside
  SF/Trigger at that stage without thorough analysis. The check for
  them is already done in the parser by calling
  is_not_allowed_in_function()
sql/sql_yacc.yy:
  By listing SQLCOM_FLUSH as command which implies COMMIT
  in sp_get_flags_for_command() the check in sql_yacc.yy is
  obsolete.

mysql-test/r/sp-error.result

@@ -634,6 +634,45 @@ flush tables;
 return 5;
 end|
 ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin reset query cache;
+return 1; end|
+ERROR 0A000: RESET is not allowed in stored function or trigger
+create function bug8409() returns int begin reset master;
+return 1; end|
+ERROR 0A000: RESET is not allowed in stored function or trigger
+create function bug8409() returns int begin reset slave;
+return 1; end|
+ERROR 0A000: RESET is not allowed in stored function or trigger
+create function bug8409() returns int begin flush hosts;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush privileges;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush tables with read lock;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush tables;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush logs;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush status;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush slave;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush master;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush des_key_file;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create function bug8409() returns int begin flush user_resources;
+return 1; end|
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
 create procedure bug9529_901234567890123456789012345678901234567890123456789012345()
 begin
 end|

mysql-test/r/trigger.result

@@ -626,12 +626,51 @@ Trigger	Event	Table	Statement	Timing	Created	sql_mode	Definer
 t1_bi	INSERT	t1	set new.a = '2004-01-00'	BEFORE	#		root@localhost
 drop table t1;
 create table t1 (id int);
+create trigger t1_ai after insert on t1 for each row reset query cache;
+ERROR 0A000: RESET is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row reset master;
+ERROR 0A000: RESET is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row reset slave;
+ERROR 0A000: RESET is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush hosts;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush tables with read lock;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush logs;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush status;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush slave;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush master;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush des_key_file;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+create trigger t1_ai after insert on t1 for each row flush user_resources;
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
 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;
+drop procedure if exists p1;
 create trigger t1_ai after insert on t1 for each row call p1();
+create procedure p1() flush tables;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() reset query cache;
+insert into t1 values (0);
+ERROR 0A000: RESET is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() reset master;
+insert into t1 values (0);
+ERROR 0A000: RESET is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() reset slave;
+insert into t1 values (0);
+ERROR 0A000: RESET is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush hosts;
 insert into t1 values (0);
 ERROR 0A000: FLUSH is not allowed in stored function or trigger
 drop procedure p1;
@@ -639,6 +678,38 @@ create procedure p1() flush privileges;
 insert into t1 values (0);
 ERROR 0A000: FLUSH is not allowed in stored function or trigger
 drop procedure p1;
+create procedure p1() flush tables with read lock;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush tables;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush logs;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush status;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush slave;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush master;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush des_key_file;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
+create procedure p1() flush user_resources;
+insert into t1 values (0);
+ERROR 0A000: FLUSH is not allowed in stored function or trigger
+drop procedure p1;
 drop table t1;
 create table t1 (id int, data int, username varchar(16));
 insert into t1 (id, data) values (1, 0);

mysql-test/t/sp-error.test

@@ -899,6 +899,45 @@ begin
   flush tables;
   return 5;
 end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin reset query cache;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin reset master;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin reset slave;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush hosts;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush privileges;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush tables with read lock;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush tables;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush logs;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush status;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush slave;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush master;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush des_key_file;
+return 1; end|
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create function bug8409() returns int begin flush user_resources;
+return 1; end|
 
 
 #

mysql-test/t/trigger.test

@@ -651,17 +651,105 @@ drop table t1;
 # 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 reset query cache;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row reset master;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row reset slave;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush hosts;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush tables with read lock;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush logs;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush status;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush slave;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush master;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush des_key_file;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+create trigger t1_ai after insert on t1 for each row flush user_resources;
+--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;
+--disable_warnings
+drop procedure if exists p1;
+--enable_warnings
+
 create trigger t1_ai after insert on t1 for each row call p1();
+create procedure p1() flush tables;
 --error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
 insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() reset query cache;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() reset master;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() reset slave;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush hosts;
+--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;
+create procedure p1() flush tables with read lock;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush tables;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush logs;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush status;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush slave;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush master;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush des_key_file;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
+drop procedure p1;
+create procedure p1() flush user_resources;
+--error ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG
+insert into t1 values (0);
+
 drop procedure p1;
 drop table t1;
 

sql/sp_head.cc

@@ -230,6 +230,12 @@ sp_get_flags_for_command(LEX *lex)
     else
       flags= sp_head::HAS_COMMIT_OR_ROLLBACK;
     break;
+  case SQLCOM_FLUSH:
+    flags= sp_head::HAS_SQLCOM_FLUSH;
+    break;
+  case SQLCOM_RESET:
+    flags= sp_head::HAS_SQLCOM_RESET;
+    break;
   case SQLCOM_CREATE_INDEX:
   case SQLCOM_CREATE_DB:
   case SQLCOM_CREATE_VIEW:

sql/sp_head.h

@@ -115,7 +115,9 @@ class sp_head :private Query_arena
     IS_INVOKED= 32,             // Is set if this sp_head is being used
     HAS_SET_AUTOCOMMIT_STMT= 64,// Is set if a procedure with 'set autocommit'
     /* Is set if a procedure with COMMIT (implicit or explicit) | ROLLBACK */
-    HAS_COMMIT_OR_ROLLBACK= 128
+    HAS_COMMIT_OR_ROLLBACK= 128,
+    HAS_SQLCOM_RESET= 2048,
+    HAS_SQLCOM_FLUSH= 4096
   };
 
   /* TYPE_ENUM_FUNCTION, TYPE_ENUM_PROCEDURE or TYPE_ENUM_TRIGGER */
@@ -335,14 +337,16 @@ class sp_head :private Query_arena
       my_error(ER_SP_NO_RETSET, MYF(0), where);
     else if (m_flags & HAS_SET_AUTOCOMMIT_STMT)
       my_error(ER_SP_CANT_SET_AUTOCOMMIT, MYF(0));
-    else if (m_type != TYPE_ENUM_PROCEDURE &&
-             (m_flags & sp_head::HAS_COMMIT_OR_ROLLBACK))
-    {
+    else if (m_flags & HAS_COMMIT_OR_ROLLBACK)
       my_error(ER_COMMIT_NOT_ALLOWED_IN_SF_OR_TRG, MYF(0));
-      return TRUE;
-    }
+    else if (m_flags & HAS_SQLCOM_RESET)
+      my_error(ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG, MYF(0), "RESET");
+    else if (m_flags & HAS_SQLCOM_FLUSH)
+      my_error(ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG, MYF(0), "FLUSH");
+
     return test(m_flags &
-		(CONTAINS_DYNAMIC_SQL|MULTI_RESULTS|HAS_SET_AUTOCOMMIT_STMT));
+		(CONTAINS_DYNAMIC_SQL|MULTI_RESULTS|HAS_SET_AUTOCOMMIT_STMT|
+                 HAS_COMMIT_OR_ROLLBACK|HAS_SQLCOM_RESET|HAS_SQLCOM_FLUSH));
   }
 
 #ifndef DBUG_OFF

sql/sql_parse.cc

@@ -6681,11 +6681,7 @@ bool reload_acl_and_cache(THD *thd, ulong options, TABLE_LIST *tables,
   select_errors=0;				/* Write if more errors */
   bool tmp_write_to_binlog= 1;
 
-  if (thd && thd->in_sub_stmt)
-  {
-    my_error(ER_STMT_NOT_ALLOWED_IN_SF_OR_TRG, MYF(0), "FLUSH");
-    return 1;
-  }
+  DBUG_ASSERT(!thd || !thd->in_sub_stmt);
 
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   if (options & REFRESH_GRANT)

sql/sql_yacc.yy

@@ -6783,17 +6783,8 @@ flush:
 	FLUSH_SYM opt_no_write_to_binlog
 	{
 	  LEX *lex=Lex;
-	  if (lex->sphead && lex->sphead->m_type != TYPE_ENUM_PROCEDURE)
-	  {
-            /*
-              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;
+	  lex->sql_command= SQLCOM_FLUSH;
+          lex->type= 0;
           lex->no_write_to_binlog= $2;
 	}
 	flush_options