tmpfilename.hpp

//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012-2022 OpenVPN Inc.
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Affero General Public License Version 3
//    as published by the Free Software Foundation.
//
//    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 Affero General Public License for more details.
//
//    You should have received a copy of the GNU Affero General Public License
//    along with this program in the COPYING file.
//    If not, see <http://www.gnu.org/licenses/>.

#pragma once

#include <openvpn/common/path.hpp>
#include <openvpn/common/hexstr.hpp>
#include <openvpn/random/randapi.hpp>

namespace openvpn {

// Generate a temporary filename that is a variant
// of an existing filename.
inline std::string tmp_filename(const std::string &fn,
                                const std::string &tmpdir,
                                StrongRandomAPI &rng)
{
    unsigned char data[16];
    rng.rand_fill(data);
    return path::join(tmpdir, '.' + path::basename(fn).substr(0, 64) + '.' + render_hex(data, sizeof(data)));
}

} // namespace openvpn