Fix accesses to uninitialized memory (found by valgrind)

mysys/my_alloc.c:
  Added comment for free_root
sql/filesort.cc:
  Removed valgrind warning
sql/sql_select.cc:
  Remove not needed my_casedn_str() for internal files
  (Old code actually didn't do any god as it was accessing not used memory)
sql/sql_view.cc:
  Removed access to uninitialized memory
sql/table.cc:
  Cleanup of error handling

mysys/my_alloc.c

@@ -245,6 +245,19 @@ static inline void mark_blocks_free(MEM_ROOT* root)
 /*
   Deallocate everything used by alloc_root or just move
   used blocks to free list if called with MY_USED_TO_FREE
+
+  SYNOPSIS
+    free_root()
+      root		Memory root
+      MyFlags		Flags for what should be freed:
+
+        MY_MARK_BLOCKS_FREED	Don't free blocks, just mark them free
+        MY_KEEP_PREALLOC	If this is not set, then free also the
+        		        preallocated block
+
+  NOTES
+    One can call this function either with root block initialised with
+    init_alloc_root() or with a bzero()-ed block.
 */
 
 void free_root(MEM_ROOT *root, myf MyFlags)

sql/filesort.cc

@@ -1176,7 +1176,12 @@ sortlength(SORT_FIELD *sortorder, uint s_length, bool *multi_byte_charset)
       else
       {
 	sortorder->length=sortorder->field->pack_length();
-	if (use_strnxfrm((cs=sortorder->field->charset())))
+        /*
+          We must test cmp_type() to ensure that ENUM and SET are sorted
+          as numbers
+        */
+	if (use_strnxfrm((cs=sortorder->field->charset())) &&
+            sortorder->field->cmp_type() == STRING_RESULT)
 	{
 	  sortorder->need_strxnfrm= 1;
 	  *multi_byte_charset= 1;

sql/sql_select.cc

@@ -7823,12 +7823,17 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
   if (temp_pool_slot != MY_BIT_NONE) // we got a slot
     sprintf(filename, "%s_%lx_%i", tmp_file_prefix,
             current_pid, temp_pool_slot);
-  else // if we run out of slots or we are not using tempool
+  else
+  {
+    /* if we run out of slots or we are not using tempool */
     sprintf(filename,"%s%lx_%lx_%x",tmp_file_prefix,current_pid,
             thd->thread_id, thd->tmp_table++);
+  }
 
-  if (lower_case_table_names)
-    my_casedn_str(files_charset_info, path);
+  /*
+    No need for change table name to lower case as we are only creating
+    MyISAM or HEAP tables here
+  */
   sprintf(path, "%s%s", mysql_tmpdir, filename);
 
   if (group)

sql/sql_view.cc

@@ -948,11 +948,12 @@ frm_type_enum mysql_frm_type(char *path)
   {
     DBUG_RETURN(FRMTYPE_ERROR);
   }
-  length= my_read(file, (byte*) header, 10, MYF(MY_WME));
+  length= my_read(file, (byte*) header, sizeof(header), MYF(MY_WME));
   my_close(file, MYF(MY_WME));
   if (length == (int) MY_FILE_ERROR)
     DBUG_RETURN(FRMTYPE_ERROR);
-  if (!strncmp(header, "TYPE=VIEW\n", 10))
+  if (length < (int) sizeof(header) ||
+      !strncmp(header, "TYPE=VIEW\n", sizeof(header)))
     DBUG_RETURN(FRMTYPE_VIEW);
   DBUG_RETURN(FRMTYPE_TABLE);                   // Is probably a .frm table
 }