Files
OpenVPNAdapter/openvpn/common/fileatomic.hpp
Sergey Abramchuk f65d76170b Squashed 'OpenVPN Adapter/Vendors/openvpn/' content from commit da99df6
git-subtree-dir: OpenVPN Adapter/Vendors/openvpn
git-subtree-split: da99df69492256d7a18bbea303ae98457782a4bf
2017-04-09 14:13:07 +03:00

69 lines
2.2 KiB
C++

// 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) 2012-2017 OpenVPN Technologies, Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program in the COPYING file.
// If not, see <http://www.gnu.org/licenses/>.
// Atomic file-handling methods.
#ifndef OPENVPN_COMMON_FILEATOMIC_H
#define OPENVPN_COMMON_FILEATOMIC_H
#include <openvpn/common/platform.hpp>
#if defined(OPENVPN_PLATFORM_WIN)
#error atomic file methods not supported on Windows
#endif
#include <stdio.h> // for rename()
#include <errno.h>
#include <cstring>
#include <openvpn/common/file.hpp>
#include <openvpn/common/hexstr.hpp>
#include <openvpn/common/fileunix.hpp>
#include <openvpn/common/path.hpp>
#include <openvpn/random/randapi.hpp>
namespace openvpn {
// Atomically write binary buffer to file (relies on
// the atomicity of rename())
inline void write_binary_atomic(const std::string& fn,
const mode_t mode,
const Buffer& buf,
RandomAPI& rng)
{
// generate temporary filename
unsigned char data[16];
rng.rand_fill(data);
const std::string tfn = path::join(path::dirname(fn), '.' + path::basename(fn) + '.' + render_hex(data, sizeof(data)));
// write to temporary file
write_binary_unix(tfn, mode, buf);
// then move into position
if (::rename(tfn.c_str(), fn.c_str()) == -1)
{
const int eno = errno;
OPENVPN_THROW(file_unix_error, "error moving '" << tfn << "' -> '" << fn << "' : " << std::strerror(eno));
}
}
}
#endif