/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014  Regents of the University of California,
 *                     Arizona Board of Regents,
 *                     Colorado State University,
 *                     University Pierre & Marie Curie, Sorbonne University,
 *                     Washington University in St. Louis,
 *                     Beijing Institute of Technology
 *
 * This file is part of NFD (Named Data Networking Forwarding Daemon).
 * See AUTHORS.md for complete list of NFD authors and contributors.
 *
 * NFD 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,
 * either version 3 of the License, or (at your option) any later version.
 *
 * NFD 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
 * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 **/

#ifndef NFD_CORE_PRIVILEGE_HELPER_HPP
#define NFD_CORE_PRIVILEGE_HELPER_HPP

#include "common.hpp"

#include <unistd.h>

namespace nfd {

class PrivilegeHelper
{
public:

  /// \brief PrivilegeHelper::Error represents a serious seteuid/gid failure and
  ///        should only be caught by main in as part of a graceful program termination.
  class Error
  {
  public:
    explicit
    Error(const std::string& what)
      : m_whatMessage(what)
    {
    }

    const char*
    what() const
    {
      return m_whatMessage.c_str();
    }

  private:
    const std::string m_whatMessage;
  };

  static void
  initialize(const std::string& userName, const std::string& groupName);

  static void
  drop();

  static void
  runElevated(function<void()> f);

private:

  static void
  raise();

private:

  static uid_t s_normalUid;
  static gid_t s_normalGid;

  static uid_t s_privilegedUid;
  static gid_t s_privilegedGid;
};

} // namespace nfd

#endif // NFD_CORE_PRIVILEGE_HELPER_HPP