Fixed stack overrun with some INSERT ... SELECT ... GROUP BY queries (Bug #3265)

Ensure that raid_chunks is not set to higher than 255 as this could cause problems with DROP DATABASE. (Bug #3182)


mysql-test/r/raid.result:
  Test of raid_chunks > 255
mysql-test/t/raid.test:
  Test of raid_chunks > 255
sql/item.cc:
  Fixed wrong usage of str_value in Item::save_in_field
  This could caused a stack overrun with some very special INSERT ... SELECT ... GROUP BY queries where the GROUP BY value was an expression that generated a NULL value. (Bug #3265)
  The Item_copy_string::save_in_field() function is from 4.1 and helps optimized this case a bit
sql/item.h:
  Fixed wrong usage of str_value in Item_copy_string::save_in_field
sql/sql_insert.cc:
  More debug information
sql/table.cc:
  Ensure that raid_chunks is not set to higher than 255 as this could cause problems with DROP DATABASE.
  Another problem with values > 255 is that in the .frm file we store the chunks value in one byte.
  (Bug #3182)

mysql-test/r/raid.result

@@ -2,6 +2,14 @@ create database test_raid;
 create table test_raid.r1 (i int) raid_type=1;
 create table test_raid.r2 (i int) raid_type=1 raid_chunks=32;
 drop database test_raid;
+create database test_raid;
+create table test_raid.r2 (i int) raid_type=1 raid_chunks=257;
+show create table test_raid.r2;
+Table	Create Table
+r2	CREATE TABLE `r2` (
+  `i` int(11) default NULL
+) TYPE=MyISAM RAID_TYPE=striped RAID_CHUNKS=255 RAID_CHUNKSIZE=256
+drop database test_raid;
 DROP TABLE IF EXISTS t1,t2;
 CREATE TABLE t1 (
 id int unsigned not null auto_increment primary key,

mysql-test/t/raid.test

@@ -11,6 +11,15 @@ create database test_raid;
 create table test_raid.r1 (i int) raid_type=1;
 create table test_raid.r2 (i int) raid_type=1 raid_chunks=32;
 drop database test_raid;
+
+#
+# Bug #3182: Test using more than 257 raid chunks
+#
+create database test_raid;
+create table test_raid.r2 (i int) raid_type=1 raid_chunks=257;
+show create table test_raid.r2;
+drop database test_raid;
+
 DROP TABLE IF EXISTS t1,t2;
 CREATE TABLE t1 (
 id int unsigned not null auto_increment primary key,

sql/item.cc

@@ -322,6 +322,15 @@ String *Item_copy_string::val_str(String *str)
   return &str_value;
 }
 
+bool Item_copy_string::save_in_field(Field *field, bool no_conversions)
+{
+  if (null_value)
+    return set_field_to_null(field);
+  field->set_notnull();
+  field->store(str_value.ptr(), str_value.length());
+  return 0;
+}
+
 /*
 ** Functions to convert item to field (for send_fields)
 */
@@ -520,7 +529,10 @@ bool Item::save_in_field(Field *field, bool no_conversions)
     str_value.set_quick(buff,sizeof(buff));
     result=val_str(&str_value);
     if (null_value)
+    {
+      str_value.set_quick(0, 0);
       return set_field_to_null_with_conversions(field, no_conversions);
+    }
     field->set_notnull();
     field->store(result->ptr(),result->length());
     str_value.set_quick(0, 0);

sql/item.h

@@ -499,6 +499,7 @@ class Item_copy_string :public Item
   String *val_str(String*);
   void make_field(Send_field *field) { item->make_field(field); }
   void copy();
+  bool save_in_field(Field *field, bool no_conversions);
   table_map used_tables() const { return (table_map) 1L; }
   bool const_item() const { return 0; }
   bool is_null() { return null_value; }

sql/sql_insert.cc

@@ -391,6 +391,7 @@ int write_record(TABLE *table,COPY_INFO *info)
 {
   int error;
   char *key=0;
+  DBUG_ENTER("write_record");
 
   info->records++;
   if (info->handle_duplicates == DUP_REPLACE)
@@ -474,14 +475,14 @@ int write_record(TABLE *table,COPY_INFO *info)
     info->copied++;
   if (key)
     my_safe_afree(key,table->max_unique_length,MAX_KEY_LENGTH);
-  return 0;
+  DBUG_RETURN(0);
 
 err:
   if (key)
     my_afree(key);
   info->last_errno= error;
   table->file->print_error(error,MYF(0));
-  return 1;
+  DBUG_RETURN(1);
 }
 
 
@@ -1342,24 +1343,25 @@ select_insert::~select_insert()
 
 bool select_insert::send_data(List<Item> &values)
 {
+  DBUG_ENTER("select_insert::send_data");
   if (thd->offset_limit)
   {						// using limit offset,count
     thd->offset_limit--;
-    return 0;
+    DBUG_RETURN(0);
   }
   if (fields->elements)
     fill_record(*fields, values, 1);
   else
     fill_record(table->field, values, 1);
   if (write_record(table,&info))
-    return 1;
+    DBUG_RETURN(1);
   if (table->next_number_field)		// Clear for next record
   {
     table->next_number_field->reset();
     if (! last_insert_id && thd->insert_id_used)
       last_insert_id=thd->insert_id();
   }
-  return 0;
+  DBUG_RETURN(0);
 }
 
 

sql/table.cc

@@ -1040,6 +1040,11 @@ File create_frm(register my_string name, uint reclength, uchar *fileinfo,
   if (create_info->min_rows > ~(ulong) 0)
     create_info->min_rows= ~(ulong) 0;
 #endif
+  /*
+    Ensure that raid_chunks can't be larger than 255, as this would cause
+    problems with drop database
+  */
+  set_if_smaller(create_info->raid_chunks, 255);
 
   if ((file=my_create(name,CREATE_MODE,O_RDWR | O_TRUNC,MYF(MY_WME))) >= 0)
   {