MDEV-21689 Add Sql_cmd for GRANT/REVOKE statements

Rewriting GRANT/REVOKE grammar to use more bison stack and use Sql_cmd_ style

1. Removing a few members from LEX:
   - uint grant, grant_to_col, which_columns
   - List<LEX_COLUMN> columns
   - bool all_privileges
2. Adding classes Grand_object_name, Lex_grant_object_name
3. Adding classes Grand_privilege, Lex_grand_privilege
4. Adding struct Lex_column_list_privilege_st, class Lex_column_list_privilege
5. Rewriting the GRANT/REVOKE grammar to use new classes and pass them through
   bison stack (rather than directly access LEX members)
6. Adding classes Sql_cmd_grant* and Sql_cmd_revoke*,
   changing GRANT/REVOKE to use LEX::m_sql_cmd.
7. Adding the "sp_handler" grammar rule and removing some duplicate grammar
   for GRANT/REVOKE for different kinds of SP objects.
8. Adding a new rule comma_separated_ident_list, reusing it in:
   - with_column_list
   - colum_list_privilege

libmysqld/CMakeLists.txt

@@ -47,7 +47,8 @@ SET(SQL_EMBEDDED_SOURCES emb_qcache.cc libmysqld.c lib_sql.cc
            ../sql/password.c ../sql/discover.cc ../sql/derror.cc 
            ../sql/field.cc ../sql/field_conv.cc ../sql/field_comp.cc
            ../sql/filesort_utils.cc ../sql/sql_digest.cc
-           ../sql/filesort.cc ../sql/gstream.cc ../sql/slave.cc
+           ../sql/filesort.cc ../sql/grant.cc
+           ../sql/gstream.cc ../sql/slave.cc
            ../sql/signal_handler.cc
            ../sql/handler.cc ../sql/hash_filo.cc ../sql/hostname.cc 
            ../sql/init.cc ../sql/item_buff.cc ../sql/item_cmpfunc.cc 

sql/CMakeLists.txt

@@ -129,6 +129,7 @@ SET (SQL_SOURCE
                sql_reload.cc
 
                # added in MariaDB:
+               grant.cc
                sql_explain.cc
                sql_analyze_stmt.cc
                sql_join_cache.cc

sql/grant.cc

@@ -0,0 +1,108 @@
+/*
+   Copyright (c) 2009, 2020, MariaDB Corporation
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+#include "mariadb.h"
+#include "sql_acl.h"
+
+
+bool Grant_privilege::add_column_privilege(THD *thd,
+                                           const Lex_ident_sys &name,
+                                           uint which_grant)
+{
+  String *new_str= new (thd->mem_root) String((const char*) name.str,
+                                              name.length,
+                                              system_charset_info);
+  if (unlikely(new_str == NULL))
+    return true;
+  List_iterator <LEX_COLUMN> iter(m_columns);
+  class LEX_COLUMN *point;
+  while ((point=iter++))
+  {
+    if (!my_strcasecmp(system_charset_info,
+                       point->column.c_ptr(), new_str->c_ptr()))
+      break;
+  }
+  m_column_privilege_total|= which_grant;
+  if (point)
+  {
+    point->rights |= which_grant;
+    return false;
+  }
+
+  LEX_COLUMN *col= new (thd->mem_root) LEX_COLUMN(*new_str, which_grant);
+  if (unlikely(col == NULL))
+    return true;
+  return m_columns.push_back(col, thd->mem_root);
+}
+
+
+bool Grant_privilege::add_column_list_privilege(THD *thd,
+                                                List<Lex_ident_sys> &list,
+                                                uint privilege)
+{
+  Lex_ident_sys *col;
+  List_iterator<Lex_ident_sys> it(list);
+  while ((col= it++))
+  {
+    if (add_column_privilege(thd, *col, privilege))
+      return true;
+  }
+  return false;
+}
+
+
+uint Grant_object_name::all_privileges_by_type() const
+{
+  switch (m_type) {
+  case STAR:        return DB_ACLS & ~GRANT_ACL;
+  case IDENT_STAR:  return DB_ACLS & ~GRANT_ACL;
+  case STAR_STAR:   return GLOBAL_ACLS & ~GRANT_ACL;
+  case TABLE_IDENT: return TABLE_ACLS & ~GRANT_ACL;
+  }
+  return 0;
+}
+
+
+bool Grant_privilege::set_object_name(THD *thd,
+                                      const Grant_object_name &ident,
+                                      SELECT_LEX *sel,
+                                      uint with_grant_option)
+{
+  DBUG_ASSERT(!m_all_privileges || !m_columns.elements);
+
+  m_db= ident.m_db;
+  if (m_all_privileges)
+    m_object_privilege= ident.all_privileges_by_type();
+  m_object_privilege|= with_grant_option;
+  switch (ident.m_type)
+  {
+  case Lex_grant_object_name::STAR:
+  case Lex_grant_object_name::IDENT_STAR:
+  case Lex_grant_object_name::STAR_STAR:
+    if (!m_all_privileges && m_columns.elements)
+    {
+      // e.g. GRANT SELECT (a) ON db.*
+      my_error(ER_ILLEGAL_GRANT_FOR_TABLE, MYF(0));
+      return true;
+    }
+    return false;
+  case Lex_grant_object_name::TABLE_IDENT:
+    m_db= ident.m_table_ident->db;
+    return !sel->add_table_to_list(thd, ident.m_table_ident,
+                                   NULL, TL_OPTION_UPDATING);
+  }
+  return false; // Make gcc happy
+}

sql/grant.h

@@ -0,0 +1,96 @@
+/*
+   Copyright (c) 2020, MariaDB Corporation.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA */
+
+#ifndef SQL_GRANT_INCLUDED
+#define SQL_GRANT_INCLUDED
+
+#include "lex_string.h"
+
+class LEX_COLUMN;
+class Lex_ident_sys;
+class Table_ident;
+
+/*
+  Represents the object name in this standard SQL grammar:
+    GRANT <object privileges> ON <object name>
+*/
+class Grant_object_name
+{
+public:
+  enum Type
+  {
+    STAR,            // ON *
+    IDENT_STAR,      // ON db.*
+    STAR_STAR,       // ON *.*
+    TABLE_IDENT      // ON db.name
+  };
+  Lex_cstring m_db;
+  Table_ident *m_table_ident;
+  Type m_type;
+public:
+  Grant_object_name(Table_ident *table_ident)
+   :m_table_ident(table_ident),
+    m_type(TABLE_IDENT)
+  { }
+  Grant_object_name(const LEX_CSTRING &db, Type type)
+   :m_db(db),
+    m_table_ident(NULL),
+    m_type(type)
+  { }
+  uint all_privileges_by_type() const;
+};
+
+
+
+/*
+  Represents standard SQL statements described by:
+  - <grant privilege statement>
+  - <revoke privilege statement>
+*/
+class Grant_privilege
+{
+protected:
+  List<LEX_COLUMN> m_columns;
+  Lex_cstring m_db;
+  uint m_object_privilege;
+  uint m_column_privilege_total;
+  bool m_all_privileges;
+public:
+  Grant_privilege()
+   :m_object_privilege(0), m_column_privilege_total(0), m_all_privileges(false)
+  { }
+  Grant_privilege(uint privilege, bool all_privileges)
+   :m_object_privilege(privilege),
+    m_column_privilege_total(0),
+    m_all_privileges(all_privileges)
+  { }
+  void add_object_privilege(uint privilege)
+  {
+    m_object_privilege|= privilege;
+  }
+  bool add_column_privilege(THD *thd, const Lex_ident_sys &col,
+                            uint privilege);
+  bool add_column_list_privilege(THD *thd, List<Lex_ident_sys> &list,
+                                 uint privilege);
+  bool set_object_name(THD *thd,
+                       const Grant_object_name &ident,
+                       SELECT_LEX *sel,
+                       uint with_grant_option);
+  const List<LEX_COLUMN> & columns() const { return m_columns; }
+};
+
+
+#endif // SQL_GRANT_INCLUDED

sql/lex_string.h

@@ -30,6 +30,10 @@ class Lex_cstring : public LEX_CSTRING
     str= NULL;
     length= 0;
   }
+  Lex_cstring(const LEX_CSTRING &str)
+  {
+    LEX_CSTRING::operator=(str);
+  }
   Lex_cstring(const char *_str, size_t _len)
   {
     str= _str;