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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) 2012-2022 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/>.
#ifndef OPENVPN_COMMON_STOP_H
#define OPENVPN_COMMON_STOP_H
#include <vector>
#include <functional>
#include <utility>
#include <mutex>
#include <openvpn/common/exception.hpp>
OPENVPN_EXCEPTION_INHERIT(std::range_error, openvpn_stop_limit);
namespace openvpn {
class Stop
{
public:
class Scope
{
friend Stop;
public:
Scope(Stop *stop_arg, std::function<void()> &&method_arg)
: stop(stop_arg),
method(std::move(method_arg)),
index(-1)
{
constexpr int stop_index_limit = 1000;
if (stop)
{
std::lock_guard<std::recursive_mutex> lock(stop->mutex);
if (stop->stop_called)
{
// stop already called, call method immediately
method();
}
else
{
if (index > stop_index_limit)
throw openvpn_stop_limit("Stop count limit exceeded");
index = static_cast<decltype(index)>(stop->scopes.size());
stop->scopes.push_back(this);
}
}
}
~Scope()
{
if (stop)
{
std::lock_guard<std::recursive_mutex> lock(stop->mutex);
if (index >= 0 && index < static_cast<int>(stop->scopes.size()) && stop->scopes[index] == this)
{
stop->scopes[index] = nullptr;
stop->prune();
}
}
}
private:
Scope(const Scope &) = delete;
Scope &operator=(const Scope &) = delete;
Stop *const stop;
const std::function<void()> method;
int index;
};
Stop()
{
}
void stop()
{
std::lock_guard<std::recursive_mutex> lock(mutex);
stop_called = true;
while (scopes.size())
{
Scope *scope = scopes.back();
scopes.pop_back();
if (scope)
{
scope->index = -1;
scope->method();
}
}
}
static bool is_triggered(const Stop *stop)
{
return stop && stop->stop_called;
}
Stop(const Stop &) = delete;
Stop &operator=(const Stop &) = delete;
private:
void prune()
{
while (scopes.size() && !scopes.back())
scopes.pop_back();
}
std::recursive_mutex mutex;
std::vector<Scope *> scopes;
volatile bool stop_called = false;
};
} // namespace openvpn
#endif
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