Bug #37339: SHOW VARIABLES not working properly with multi-byte datadir

      
The SHOW VARIABLES LIKE .../SELECT @@/SELECT ... FROM INFORMATION_SCHEMA.VARIABLES
were assuming that all the system variables are in system charset (UTF-8).
However the variables that are settable through command line will have a different
character set (character_set_filesystem).
Fixed the server to remember the correct character set of basedir, datadir, tmpdir,
ssl, plugin_dir, slave_load_tmpdir, innodb variables; init_connect and init_slave 
variables and use it when processing data.

mysql-test/r/ctype_filesystem.result:
  Bug #37339: test case (should be in utf-8)
mysql-test/t/ctype_filesystem-master.opt:
  Bug #37339: test case (should be in ISO-8859-1)
mysql-test/t/ctype_filesystem.test:
  Bug #37339: test case
sql/mysqld.cc:
  Bug #37339: remember the correct character set for init_slave and init_connect
sql/set_var.cc:
  Bug #37339: 
    - remember the character set of the relevant variables
    - implement storing and using the correct 
      character set
sql/set_var.h:
  Bug #37339: implement storing and using the correct 
  character set
sql/sql_show.cc:
  Bug #37339: implement storing and using the correct 
  character set

mysql-test/r/ctype_filesystem.result

+SET CHARACTER SET utf8;
+SHOW VARIABLES like 'character_sets_dir';
+Variable_name	Value
+character_sets_dir	/ß/
+SHOW VARIABLES like 'character_set_filesystem';
+Variable_name	Value
+character_set_filesystem	latin1
+SHOW VARIABLES like 'character_set_client';
+Variable_name	Value
+character_set_client	utf8
+SET CHARACTER SET default;

mysql-test/t/ctype_filesystem-master.opt

+--character-sets-dir=/ß
+--character-set-filesystem=latin1

mysql-test/t/ctype_filesystem.test

+SET CHARACTER SET utf8;
+SHOW VARIABLES like 'character_sets_dir';
+SHOW VARIABLES like 'character_set_filesystem';
+SHOW VARIABLES like 'character_set_client';
+SET CHARACTER SET default;

sql/mysqld.cc

@@ -3035,12 +3035,14 @@ static int init_common_variables(const char *conf_file_name, int argc,
     sys_init_connect.value_length= strlen(opt_init_connect);
   else
     sys_init_connect.value=my_strdup("",MYF(0));
+  sys_init_connect.is_os_charset= TRUE;
 
   sys_init_slave.value_length= 0;
   if ((sys_init_slave.value= opt_init_slave))
     sys_init_slave.value_length= strlen(opt_init_slave);
   else
     sys_init_slave.value=my_strdup("",MYF(0));
+  sys_init_slave.is_os_charset= TRUE;
 
   if (use_temp_pool && bitmap_init(&temp_pool,0,1024,1))
     return 1;

sql/set_var.h

@@ -46,9 +46,17 @@ class sys_var
   
   sys_after_update_func after_update;
   bool no_support_one_shot;
+  /*
+    true if the value is in character_set_filesystem, 
+    false otherwise.
+    Note that we can't use a pointer to the charset as the system var is 
+    instantiated in global scope and the charset pointers are initialized
+    later.
+  */  
+  bool is_os_charset;
   sys_var(const char *name_arg, sys_after_update_func func= NULL)
     :name(name_arg), after_update(func)
-    , no_support_one_shot(1)
+    , no_support_one_shot(1), is_os_charset(FALSE)
   {}
   virtual ~sys_var() {}
   virtual bool check(THD *thd, set_var *var);
@@ -68,6 +76,7 @@ class sys_var
   Item *item(THD *thd, enum_var_type type, LEX_STRING *base);
   virtual bool is_struct() { return 0; }
   virtual bool is_readonly() const { return 0; }
+  CHARSET_INFO *charset(THD *thd);
 };
 
 
@@ -247,6 +256,17 @@ class sys_var_const_str :public sys_var
 };
 
 
+class sys_var_const_os_str: public sys_var_const_str
+{
+public:
+  sys_var_const_os_str(const char *name_arg, const char *value_arg)
+    :sys_var_const_str(name_arg, value_arg)
+  { 
+    is_os_charset= TRUE; 
+  }
+};
+
+
 class sys_var_const_str_ptr :public sys_var
 {
 public:
@@ -276,6 +296,17 @@ class sys_var_const_str_ptr :public sys_var
 };
 
 
+class sys_var_const_os_str_ptr :public sys_var_const_str_ptr
+{
+public:
+  sys_var_const_os_str_ptr(const char *name_arg, char **value_arg)
+    :sys_var_const_str_ptr(name_arg, value_arg)
+  {
+    is_os_charset= TRUE; 
+  }
+};
+
+
 class sys_var_enum :public sys_var
 {
   uint	*value; 
@@ -791,6 +822,20 @@ class sys_var_readonly: public sys_var
   bool is_readonly() const { return 1; }
 };
 
+
+class sys_var_readonly_os: public sys_var_readonly
+{
+public:
+  sys_var_readonly_os(const char *name_arg, enum_var_type type,
+		   SHOW_TYPE show_type_arg,
+		   sys_value_ptr_func value_ptr_func_arg)
+    :sys_var_readonly(name_arg, type, show_type_arg, value_ptr_func_arg)
+  {
+    is_os_charset= TRUE;
+  }
+};
+
+
 class sys_var_thd_time_zone :public sys_var_thd
 {
 public:

sql/sql_show.cc

@@ -1441,6 +1441,7 @@ static bool show_status_array(THD *thd, const char *wild,
   char name_buffer[80];
   int len;
   LEX_STRING null_lex_str;
+  CHARSET_INFO *charset= system_charset_info;
   DBUG_ENTER("show_status_array");
 
   null_lex_str.str= 0;				// For sys_var->value_ptr()
@@ -1469,9 +1470,10 @@ static bool show_status_array(THD *thd, const char *wild,
         long nr;
         if (show_type == SHOW_SYS)
         {
-          show_type= ((sys_var*) value)->show_type();
-          value=     (char*) ((sys_var*) value)->value_ptr(thd, value_type,
-                                                           &null_lex_str);
+          sys_var *var= ((sys_var *) value);
+          show_type= var->show_type();
+          value= (char*) var->value_ptr(thd, value_type, &null_lex_str);
+          charset= var->charset(thd);
         }
 
         pos= end= buff;
@@ -1794,7 +1796,7 @@ static bool show_status_array(THD *thd, const char *wild,
         restore_record(table, s->default_values);
         table->field[0]->store(name_buffer, strlen(name_buffer),
                                system_charset_info);
-        table->field[1]->store(pos, (uint32) (end - pos), system_charset_info);
+        table->field[1]->store(pos, (uint32) (end - pos), charset);
         if (schema_table_store_record(thd, table))
           DBUG_RETURN(TRUE);
       }