From 94bd96e815333955974b53ca42e4480c8754b75c Mon Sep 17 00:00:00 2001
From: Vladislav Vaintroub <vvaintroub@mysql.com>
Date: Tue, 23 Feb 2010 12:48:26 +0100
Subject: [PATCH] Bug#43201 : Stack overrun when running sp-error test. It
 appears that stack overflow checks for recusrive stored procedure calls, that
 run in the normal server, did not work in embedded and were  dummified with
 preprocessor magic( #ifndef EMBEDDED_SERVER ).

 The fix is to remove ifdefs, there is no reason not to run overflow checks
 and crash in deeply recursive calls.

 Note: Start of the stack (thd->thread_stack variable) in embedded is not
necessarily exact but stil provides the best guess. Unless the caller of
mysql_read_connect()   is already deep in the stack, thd->thread_stack
variable should approximate stack  start address well.
---
 sql/item_cmpfunc.cc | 4 ----
 sql/item_func.cc    | 4 ----
 sql/opt_range.cc    | 2 --
 sql/sql_parse.cc    | 3 +--
 sql/sql_select.cc   | 2 --
 5 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 1da383ce3e9..ed465cbe280 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -2865,9 +2865,7 @@ bool Item_func_case::fix_fields(THD *thd, Item **ref)
     buff should match stack usage from
     Item_func_case::val_int() -> Item_func_case::find_item()
   */
-#ifndef EMBEDDED_LIBRARY
   uchar buff[MAX_FIELD_WIDTH*2+sizeof(String)*2+sizeof(String*)*2+sizeof(double)*2+sizeof(longlong)*2];
-#endif
   bool res= Item_func::fix_fields(thd, ref);
   /*
     Call check_stack_overrun after fix_fields to be sure that stack variable
@@ -4081,9 +4079,7 @@ Item_cond::fix_fields(THD *thd, Item **ref)
   DBUG_ASSERT(fixed == 0);
   List_iterator<Item> li(list);
   Item *item;
-#ifndef EMBEDDED_LIBRARY
   uchar buff[sizeof(char*)];			// Max local vars in function
-#endif
   not_null_tables_cache= used_tables_cache= 0;
   const_item_cache= 1;
   /*
diff --git a/sql/item_func.cc b/sql/item_func.cc
index 75f8b2045b5..e49ee4346b1 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -151,9 +151,7 @@ Item_func::fix_fields(THD *thd, Item **ref)
 {
   DBUG_ASSERT(fixed == 0);
   Item **arg,**arg_end;
-#ifndef EMBEDDED_LIBRARY			// Avoid compiler warning
   uchar buff[STACK_BUFF_ALLOC];			// Max argument in function
-#endif
 
   used_tables_cache= not_null_tables_cache= 0;
   const_item_cache=1;
@@ -2839,9 +2837,7 @@ bool
 udf_handler::fix_fields(THD *thd, Item_result_field *func,
 			uint arg_count, Item **arguments)
 {
-#ifndef EMBEDDED_LIBRARY			// Avoid compiler warning
   uchar buff[STACK_BUFF_ALLOC];			// Max argument in function
-#endif
   DBUG_ENTER("Item_udf_func::fix_fields");
 
   if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index b9ea8c7c991..68285563239 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -2266,9 +2266,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
   keys_to_use.intersect(head->keys_in_use_for_query);
   if (!keys_to_use.is_clear_all())
   {
-#ifndef EMBEDDED_LIBRARY                      // Avoid compiler warning
     uchar buff[STACK_BUFF_ALLOC];
-#endif
     MEM_ROOT alloc;
     SEL_TREE *tree= NULL;
     KEY_PART *key_parts;
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index b0d8614dc84..c7e1be2237b 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -5171,7 +5171,6 @@ bool check_global_access(THD *thd, ulong want_access)
 	Check stack size; Send error if there isn't enough stack to continue
 ****************************************************************************/
 
-#ifndef EMBEDDED_LIBRARY
 
 #if STACK_DIRECTION < 0
 #define used_stack(A,B) (long) (A - B)
@@ -5209,7 +5208,7 @@ bool check_stack_overrun(THD *thd, long margin,
 #endif
   return 0;
 }
-#endif /* EMBEDDED_LIBRARY */
+
 
 #define MY_YACC_INIT 1000			// Start with big alloc
 #define MY_YACC_MAX  32000			// Because of 'short'
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index c37aeb39f6c..468f81a7d87 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -2516,9 +2516,7 @@ static ha_rows get_quick_record_count(THD *thd, SQL_SELECT *select,
 {
   int error;
   DBUG_ENTER("get_quick_record_count");
-#ifndef EMBEDDED_LIBRARY                      // Avoid compiler warning
   uchar buff[STACK_BUFF_ALLOC];
-#endif
   if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
     DBUG_RETURN(0);                           // Fatal error flag is set
   if (select)