bk commit into 5.0 tree (ramil:1.2478) BUG#21476

[ramil]

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ChangeSet@stripped, 2007-05-14 11:55:55+05:00, ramil@stripped +1 -0
  Fix for bug #21476: stack overflow crashes server; error-message stack reservation too
small
  
  Check for possible stack overflow in the Item_func_if::fix_fields().

  sql/item_cmpfunc.cc@stripped, 2007-05-14 11:55:53+05:00, ramil@stripped +6 -1
    Fix for bug #21476: stack overflow crashes server; error-message stack reservation too
small
    
    Check for possible stack overflow in the Item_func_if::fix_fields().

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	ramil
# Host:	ramil.myoffice.izhnet.ru
# Root:	/home/ram/work/b21476/b21476.5.0

--- 1.248/sql/item_cmpfunc.cc	2007-05-14 11:56:00 +05:00
+++ 1.249/sql/item_cmpfunc.cc	2007-05-14 11:56:00 +05:00
@@ -2010,10 +2010,15 @@ Item_func_if::fix_fields(THD *thd, Item 
 {
   DBUG_ASSERT(fixed == 0);
   args[0]->top_level_item();
-
+#ifndef EMBEDDED_LIBRARY  
+  char buff[STACK_BUFF_ALLOC];
+#endif
   if (Item_func::fix_fields(thd, ref))
     return 1;
 
+  if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
+    return TRUE;
+    
   not_null_tables_cache= (args[1]->not_null_tables() &
                           args[2]->not_null_tables());