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// 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- OpenVPN Inc.
//
// SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-only WITH openvpn3-openssl-exception
//
#ifndef OPENVPN_COMMON_TEMPFILE_H
#define OPENVPN_COMMON_TEMPFILE_H
#include <openvpn/common/platform.hpp>
#if defined(OPENVPN_PLATFORM_WIN)
#error temporary file methods not supported on Windows
#endif
#include <stdlib.h>
#include <errno.h>
#include <cstring> // for memcpy
#include <unistd.h> // for write, unlink, lseek
#include <sys/types.h> // for lseek
#include <string>
#include <memory>
#include <openvpn/common/exception.hpp>
#include <openvpn/common/numeric_cast.hpp>
#include <openvpn/common/scoped_fd.hpp>
#include <openvpn/common/write.hpp>
#include <openvpn/common/strerror.hpp>
#include <openvpn/buffer/bufread.hpp>
using openvpn::numeric_util::numeric_cast;
namespace openvpn {
class TempFile
{
public:
OPENVPN_EXCEPTION(tempfile_exception);
TempFile(const std::string &fn_template,
const bool fn_delete)
: fn(new char[fn_template.length() + 1]),
del(fn_delete)
{
constexpr char pattern[] = "XXXXXX";
constexpr size_t patternLen = sizeof(pattern) - 1;
std::memcpy(fn.get(), fn_template.c_str(), fn_template.length() + 1);
const size_t pos = fn_template.rfind(pattern);
if (pos != std::string::npos)
{
if (fn_template.length() > pos + patternLen)
{
const auto suffixlen = fn_template.length() - pos - patternLen;
fd.reset(::mkstemps(fn.get(), numeric_cast<int>(suffixlen)));
}
else
fd.reset(::mkstemp(fn.get()));
if (!fd.defined())
{
const int eno = errno;
OPENVPN_THROW(tempfile_exception, "error creating temporary file from template: " << fn_template << " : " << strerror_str(eno));
}
}
else
OPENVPN_THROW(tempfile_exception, "badly formed temporary file template: " << fn_template);
}
~TempFile()
{
fd.close();
delete_file();
}
void reset()
{
const off_t off = ::lseek(fd(), 0, SEEK_SET);
if (off < 0)
{
const int eno = errno;
OPENVPN_THROW(tempfile_exception, "seek error on temporary file: " << filename() << " : " << strerror_str(eno));
}
if (off)
OPENVPN_THROW(tempfile_exception, "unexpected seek on temporary file: " << filename());
}
void truncate()
{
reset();
if (::ftruncate(fd(), 0) < 0)
{
const int eno = errno;
OPENVPN_THROW(tempfile_exception, "ftruncate error on temporary file: " << filename() << " : " << strerror_str(eno));
}
}
void write(const std::string &content)
{
const ssize_t size = write_retry(fd(), content.c_str(), content.length());
if (size < 0)
{
const int eno = errno;
OPENVPN_THROW(tempfile_exception, "error writing to temporary file: " << filename() << " : " << strerror_str(eno));
}
else if (static_cast<std::string::size_type>(size) != content.length())
{
OPENVPN_THROW(tempfile_exception, "incomplete write to temporary file: " << filename());
}
}
std::string read()
{
BufferList buflist = buf_read(fd(), filename());
return buflist.to_string();
}
std::string filename() const
{
if (fn)
return fn.get();
else
return "";
}
void close_file()
{
if (!fd.close())
{
const int eno = errno;
OPENVPN_THROW(tempfile_exception, "error closing temporary file: " << filename() << " : " << strerror_str(eno));
}
}
void set_delete(const bool del_flag)
{
del = del_flag;
}
void delete_file()
{
if (fn && del)
{
::unlink(fn.get());
del = false;
}
}
ScopedFD fd;
private:
std::unique_ptr<char[]> fn;
bool del;
};
} // namespace openvpn
#endif
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