MDEV-7015: SET STATEMENT old_passwords has no effect

Decision about algorihtm moved on prepare phase.
Made possible to add mpore password algorithms.

mysql-test/r/set_statement.result

@@ -1070,8 +1070,6 @@ set statement character_set_filesystem=default for select 1;
 ERROR 42000: The system variable character_set_filesystem cannot be set in SET STATEMENT.
 set statement collation_connection=default for select 1;
 ERROR 42000: The system variable collation_connection cannot be set in SET STATEMENT.
-set statement old_passwords=default for select 1;
-ERROR 42000: The system variable old_passwords cannot be set in SET STATEMENT.
 set statement query_cache_type=default for select 1;
 ERROR 42000: The system variable query_cache_type cannot be set in SET STATEMENT.
 set statement wait_timeout=default for select 1;
@@ -1105,3 +1103,38 @@ week(a)
 deallocate prepare stmt1;
 drop table t1;
 set @@default_week_format=@save_week_format;
+set @save_old_passwords=@@old_passwords;
+set @@old_passwords=0;
+set statement OLD_PASSWORDS = 0 for select password('test');
+password('test')
+*94BDCEBE19083CE2A1F959FD02F964C7AF4CFC29
+set statement OLD_PASSWORDS = 1 for select password('test');
+password('test')
+378b243e220ca493
+set statement OLD_PASSWORDS = 0 for explain extended select password('test');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+Warnings:
+Note	1003	select password('test') AS `password('test')`
+set statement OLD_PASSWORDS = 1 for explain extended select password('test');
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+Warnings:
+Note	1003	select password('test') AS `password('test')`
+create table t1 (a char(10));
+insert t1 values ('qwertyuiop');
+prepare stmt1 from "select password(a) from t1";
+execute stmt1;
+password(a)
+*6063C78456BB048BAF36BE1104D12D547834DFEA
+set old_passwords=1;
+execute stmt1;
+password(a)
+2013610f6aac2950
+alter table t1 engine=myisam;
+execute stmt1;
+password(a)
+2013610f6aac2950
+deallocate prepare stmt1;
+drop table t1;
+set @@old_passwords=@save_old_passwords;

mysql-test/t/set_statement.test

@@ -1025,8 +1025,6 @@ set statement character_set_filesystem=default for select 1;
 --error ER_SET_STATEMENT_NOT_SUPPORTED
 set statement collation_connection=default for select 1;
 --error ER_SET_STATEMENT_NOT_SUPPORTED
-set statement old_passwords=default for select 1;
---error ER_SET_STATEMENT_NOT_SUPPORTED
 set statement query_cache_type=default for select 1;
 --error ER_SET_STATEMENT_NOT_SUPPORTED
 set statement wait_timeout=default for select 1;
@@ -1050,3 +1048,21 @@ deallocate prepare stmt1;
 drop table t1;
 set @@default_week_format=@save_week_format;
 
+# MDEV-7015: SET STATEMENT old_passwords has no effect
+set @save_old_passwords=@@old_passwords;
+set @@old_passwords=0;
+set statement OLD_PASSWORDS = 0 for select password('test');
+set statement OLD_PASSWORDS = 1 for select password('test');
+set statement OLD_PASSWORDS = 0 for explain extended select password('test');
+set statement OLD_PASSWORDS = 1 for explain extended select password('test');
+create table t1 (a char(10));
+insert t1 values ('qwertyuiop');
+prepare stmt1 from "select password(a) from t1";
+execute stmt1;
+set old_passwords=1;
+execute stmt1;
+alter table t1 engine=myisam;
+execute stmt1;
+deallocate prepare stmt1;
+drop table t1;
+set @@old_passwords=@save_old_passwords;

sql/item_strfunc.cc

@@ -2168,57 +2168,68 @@ void Item_func_trim::print(String *str, enum_query_type query_type)
 
 /* Item_func_password */
 
+bool Item_func_password::fix_fields(THD *thd, Item **ref)
+{
+  if (deflt)
+    alg= (thd->variables.old_passwords ? OLD : NEW);
+  return Item_str_ascii_func::fix_fields(thd, ref);
+}
+
 String *Item_func_password::val_str_ascii(String *str)
 {
   DBUG_ASSERT(fixed == 1);
   String *res= args[0]->val_str(str); 
+  switch (alg){
+  case NEW:
     check_password_policy(res);
     if (args[0]->null_value || res->length() == 0)
       return make_empty_result();
     my_make_scrambled_password(tmp_value, res->ptr(), res->length());
     str->set(tmp_value, SCRAMBLED_PASSWORD_CHAR_LENGTH, &my_charset_latin1);
-  return str;
+    break;
-}
+  case OLD:
-
-char *Item_func_password::alloc(THD *thd, const char *password, size_t pass_len)
-{
-  char *buff= (char *) thd->alloc(SCRAMBLED_PASSWORD_CHAR_LENGTH+1);
-  if (buff)
-  {
-    String *password_str= new (thd->mem_root)String(password, thd->variables.
-                                                    character_set_client);
-    check_password_policy(password_str);
-    my_make_scrambled_password(buff, password, pass_len);
-  }
-  return buff;
-}
-
-
-/* Item_func_old_password */
-
-String *Item_func_old_password::val_str_ascii(String *str)
-{
-  DBUG_ASSERT(fixed == 1);
-  String *res= args[0]->val_str(str);
     if ((null_value=args[0]->null_value))
       return 0;
     if (res->length() == 0)
       return make_empty_result();
     my_make_scrambled_password_323(tmp_value, res->ptr(), res->length());
     str->set(tmp_value, SCRAMBLED_PASSWORD_CHAR_LENGTH_323, &my_charset_latin1);
+    break;
+  default:
+    DBUG_ASSERT(0);
+  }
   return str;
 }
 
-char *Item_func_old_password::alloc(THD *thd, const char *password,
+char *Item_func_password::alloc(THD *thd, const char *password,
-                                    size_t pass_len)
+                                size_t pass_len, enum PW_Alg al)
 {
-  char *buff= (char *) thd->alloc(SCRAMBLED_PASSWORD_CHAR_LENGTH_323+1);
+  char *buff= (char *) thd->alloc((al==NEW)?
-  if (buff)
+                                  SCRAMBLED_PASSWORD_CHAR_LENGTH + 1:
+                                  SCRAMBLED_PASSWORD_CHAR_LENGTH_323 + 1);
+  if (!buff)
+    return NULL;
+
+  switch (al) {
+  case NEW:
+    {
+      String *password_str= new (thd->mem_root)String(password, thd->variables.
+                                                      character_set_client);
+      check_password_policy(password_str);
+      my_make_scrambled_password(buff, password, pass_len);
+      break;
+    }
+  case OLD:
     my_make_scrambled_password_323(buff, password, pass_len);
+    break;
+  default:
+    DBUG_ASSERT(0);
+  }
   return buff;
 }
 
 
+
 #define bin_to_ascii(c) ((c)>=38?((c)-38+'a'):(c)>=12?((c)-12+'A'):(c)+'.')
 
 String *Item_func_encrypt::val_str(String *str)

sql/item_strfunc.h

@@ -407,40 +407,32 @@ public:
 
 class Item_func_password :public Item_str_ascii_func
 {
+public:
+  enum PW_Alg {OLD, NEW};
+private:
   char tmp_value[SCRAMBLED_PASSWORD_CHAR_LENGTH+1]; 
+  enum PW_Alg alg;
+  bool deflt;
 public:
-  Item_func_password(Item *a) :Item_str_ascii_func(a) {}
+  Item_func_password(Item *a) :Item_str_ascii_func(a), alg(NEW), deflt(1) {}
+  Item_func_password(Item *a, PW_Alg al) :Item_str_ascii_func(a),
+    alg(al), deflt(0) {}
   String *val_str_ascii(String *str);
+  bool fix_fields(THD *thd, Item **ref);
   void fix_length_and_dec()
   {
-    fix_length_and_charset(SCRAMBLED_PASSWORD_CHAR_LENGTH, default_charset());
+    fix_length_and_charset((alg == 1 ?
+                            SCRAMBLED_PASSWORD_CHAR_LENGTH :
+                            SCRAMBLED_PASSWORD_CHAR_LENGTH_323),
+                           default_charset());
   }
-  const char *func_name() const { return "password"; }
+  const char *func_name() const { return ((deflt || alg == 1) ?
-  static char *alloc(THD *thd, const char *password, size_t pass_len);
+                                          "password" : "old_password"); }
+  static char *alloc(THD *thd, const char *password, size_t pass_len,
+                     enum PW_Alg al);
 };
 
 
-/*
-  Item_func_old_password -- PASSWORD() implementation used in MySQL 3.21 - 4.0
-  compatibility mode. This item is created in sql_yacc.yy when
-  'old_passwords' session variable is set, and to handle OLD_PASSWORD()
-  function.
-*/
-
-class Item_func_old_password :public Item_str_ascii_func
-{
-  char tmp_value[SCRAMBLED_PASSWORD_CHAR_LENGTH_323+1];
-public:
-  Item_func_old_password(Item *a) :Item_str_ascii_func(a) {}
-  String *val_str_ascii(String *str);
-  void fix_length_and_dec()
-  {
-    fix_length_and_charset(SCRAMBLED_PASSWORD_CHAR_LENGTH_323, default_charset());
-  } 
-  const char *func_name() const { return "old_password"; }
-  static char *alloc(THD *thd, const char *password, size_t pass_len);
-};
-
 
 class Item_func_des_encrypt :public Item_str_func
 {

sql/sql_yacc.yy

@@ -9771,16 +9771,14 @@ function_call_conflict:
           }
         | OLD_PASSWORD '(' expr ')'
           {
-            $$=  new (thd->mem_root) Item_func_old_password($3);
+            $$=  new (thd->mem_root)
+              Item_func_password($3, Item_func_password::OLD);
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
         | PASSWORD '(' expr ')'
           {
             Item* i1;
-            if (thd->variables.old_passwords)
-              i1= new (thd->mem_root) Item_func_old_password($3);
-            else
             i1= new (thd->mem_root) Item_func_password($3);
             if (i1 == NULL)
               MYSQL_YYABORT;
@@ -14898,17 +14896,19 @@ text_or_password:
           TEXT_STRING { $$=$1.str;}
         | PASSWORD '(' TEXT_STRING ')'
           {
-            $$= $3.length ? thd->variables.old_passwords ?
+            $$= $3.length ? 
-              Item_func_old_password::alloc(thd, $3.str, $3.length) :
+              Item_func_password::alloc(thd, $3.str, $3.length,
-              Item_func_password::alloc(thd, $3.str, $3.length) :
+                                        thd->variables.old_passwords ?
+                                        Item_func_password::OLD :
+                                        Item_func_password::NEW) :
               $3.str;
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
         | OLD_PASSWORD '(' TEXT_STRING ')'
           {
-            $$= $3.length ? Item_func_old_password::
+            $$= $3.length ? Item_func_password::
-              alloc(thd, $3.str, $3.length) :
+              alloc(thd, $3.str, $3.length, Item_func_password::OLD) :
               $3.str;
             if ($$ == NULL)
               MYSQL_YYABORT;

sql/sys_vars.cc

@@ -2130,7 +2130,7 @@ static bool check_old_passwords(sys_var *self, THD *thd, set_var *var)
 static Sys_var_mybool Sys_old_passwords(
        "old_passwords",
        "Use old password encryption method (needed for 4.0 and older clients)",
-       NO_SET_STMT SESSION_VAR(old_passwords), CMD_LINE(OPT_ARG),
+       SESSION_VAR(old_passwords), CMD_LINE(OPT_ARG),
        DEFAULT(FALSE), NO_MUTEX_GUARD, NOT_IN_BINLOG,
        ON_CHECK(check_old_passwords));
 export sys_var *Sys_old_passwords_ptr= &Sys_old_passwords; // for sql_acl.cc