bzr commit into mysql-5.5 branch (sergey.vojtovich:3328) Bug#11766720

[Sergey Vojtovich]

#At file:///home/svoj/mysql/server/mysql-5.5-bug59895/ based on revid:dmitry.lenev@stripped

 3328 Sergey Vojtovich	2011-02-17
      BUG#11766720 - setting storage engine to null segfaults mysqld
      
      MONTHNAME(0) claims that it is about to return NOT NULL
      value, whereas it actually returns NULL.
      
      As a result storage_engine variable (which cannot be NULL)
      protection was bypassed and NULL value was accepted, causing
      server crash.
      
      Fixed MONTHNAME(0) to report valid NULL flag.
     @ mysql-test/r/func_time.result
        A test case for BUG#11766720.
     @ mysql-test/t/func_time.test
        A test case for BUG#11766720.
     @ sql/item_timefunc.cc
        MONTHNAME(0) must report NULL, as opposed to base class
        MONTH(0) which is NOT NULL.
        
        For this purpose Item_func_monthname must implement
        it's own val_int() method, which is later used by
        Item_func::is_null().
     @ sql/item_timefunc.h
        MONTHNAME(0) must report NULL, as opposed to base class
        MONTH(0) which is NOT NULL.
        
        For this purpose Item_func_monthname must implement
        it's own val_int() method, which is later used by
        Item_func::is_null().

    modified:
      mysql-test/r/func_time.result
      mysql-test/t/func_time.test
      sql/item_timefunc.cc
      sql/item_timefunc.h
=== modified file 'mysql-test/r/func_time.result'
--- a/mysql-test/r/func_time.result	2011-02-02 18:16:06 +0000
+++ b/mysql-test/r/func_time.result	2011-02-17 12:37:31 +0000
@@ -1368,3 +1368,9 @@ SELECT SUBDATE(STR_TO_DATE(NULL,0), INTE
 SUBDATE(STR_TO_DATE(NULL,0), INTERVAL 1 HOUR)
 NULL
 #
+# BUG#59895 - setting storage engine to null segfaults mysqld
+#
+SELECT MONTHNAME(0), MONTHNAME(0) IS NULL;
+MONTHNAME(0)	MONTHNAME(0) IS NULL
+NULL	1
+#

=== modified file 'mysql-test/t/func_time.test'
--- a/mysql-test/t/func_time.test	2011-02-02 18:16:06 +0000
+++ b/mysql-test/t/func_time.test	2011-02-17 12:37:31 +0000
@@ -881,4 +881,9 @@ SELECT WEEK(STR_TO_DATE(NULL,0));
 SELECT SUBDATE(STR_TO_DATE(NULL,0), INTERVAL 1 HOUR);
 
 --echo #
+--echo # BUG#59895 - setting storage engine to null segfaults mysqld
+--echo #
+SELECT MONTHNAME(0), MONTHNAME(0) IS NULL;
+
+--echo #
 

=== modified file 'sql/item_timefunc.cc'
--- a/sql/item_timefunc.cc	2011-02-10 08:18:08 +0000
+++ b/sql/item_timefunc.cc	2011-02-17 12:37:31 +0000
@@ -1129,6 +1129,15 @@ void Item_func_monthname::fix_length_and
 }
 
 
+longlong Item_func_monthname::val_int()
+{
+  longlong month= Item_func_month::val_int();
+  if (!month)
+    null_value= 1;
+  return month;
+}
+
+
 String* Item_func_monthname::val_str(String* str)
 {
   DBUG_ASSERT(fixed == 1);
@@ -1136,12 +1145,8 @@ String* Item_func_monthname::val_str(Str
   uint month= (uint) val_int();
   uint err;
 
-  if (null_value || !month)
-  {
-    null_value=1;
+  if (null_value)
     return (String*) 0;
-  }
-  null_value=0;
   month_name= locale->month_names->type_names[month-1];
   str->copy(month_name, (uint) strlen(month_name), &my_charset_utf8_bin,
 	    collation.collation, &err);

=== modified file 'sql/item_timefunc.h'
--- a/sql/item_timefunc.h	2011-02-10 08:18:08 +0000
+++ b/sql/item_timefunc.h	2011-02-17 12:37:31 +0000
@@ -169,6 +169,7 @@ class Item_func_monthname :public Item_f
 public:
   Item_func_monthname(Item *a) :Item_func_month(a) {}
   const char *func_name() const { return "monthname"; }
+  longlong val_int();
   String *val_str(String *str);
   enum Item_result result_type () const { return STRING_RESULT; }
   void fix_length_and_dec();


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