Function check_grant_all_columns

phx_percona/percona/sql/sql_acl.cc:6202–6284

@brief check if a query can access a set of columns @param thd the current thread @param want_access_arg the privileges requested @param fields an iterator over the fields of a table reference. @return Operation status @retval 0 Success @retval 1 Falure @details This function walks over the columns of a table reference The columns may originate from different tables, de

   to check the required access privileges for the fields requested from it.
*/    
bool check_grant_all_columns(THD *thd, ulong want_access_arg, 
                             Field_iterator_table_ref *fields)
{
  Security_context *sctx= thd->security_ctx;
  ulong want_access= want_access_arg;
  const char *table_name= NULL;

  const char* db_name; 
  GRANT_INFO *grant;
  /* Initialized only to make gcc happy */
  GRANT_TABLE *grant_table= NULL;
  /* 
     Flag that gets set if privilege checking has to be performed on column
     level.
  */
  bool using_column_privileges= FALSE;

  mysql_rwlock_rdlock(&LOCK_grant);

  for (; !fields->end_of_fields(); fields->next())
  {
    const char *field_name= fields->name();

    if (table_name != fields->get_table_name())
    {
      table_name= fields->get_table_name();
      db_name= fields->get_db_name();
      grant= fields->grant();
      /* get a fresh one for each table */
      want_access= want_access_arg & ~grant->privilege;
      if (want_access)
      {
        /* reload table if someone has modified any grants */
        if (grant->version != grant_version)
        {
          grant->grant_table=
            table_hash_search(sctx->get_host()->ptr(), sctx->get_ip()->ptr(),
                              db_name, sctx->priv_user,
                              table_name, 0);	/* purecov: inspected */
          grant->version= grant_version;	/* purecov: inspected */
        }

        grant_table= grant->grant_table;
        DBUG_ASSERT (grant_table);
      }
    }

    if (want_access)
    {
      GRANT_COLUMN *grant_column= 
        column_hash_search(grant_table, field_name,
                           (uint) strlen(field_name));
      if (grant_column)
        using_column_privileges= TRUE;
      if (!grant_column || (~grant_column->rights & want_access))
        goto err;
    }
  }