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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_SIGNAL_H
#define OPENVPN_COMMON_SIGNAL_H
#include <openvpn/common/platform.hpp>
#if !defined(OPENVPN_PLATFORM_WIN)
#include <signal.h>
#include <openvpn/common/size.hpp>
#include <openvpn/common/exception.hpp>
namespace openvpn {
class Signal
{
public:
OPENVPN_SIMPLE_EXCEPTION(signal_error);
typedef void (*handler_t)(int signum);
enum
{
F_SIGINT = (1 << 0),
F_SIGTERM = (1 << 1),
F_SIGHUP = (1 << 2),
F_SIGUSR1 = (1 << 3),
F_SIGUSR2 = (1 << 4),
F_SIGPIPE = (1 << 5),
};
/**
* configure a signal handler to be active on the signal specified in the
* \c flags parameter. The signal handler will receive the original system
* signal numbers and not the ones from the enum of this class.
* @param handler
* @param flags
*/
Signal(const handler_t handler, const unsigned int flags)
{
struct sigaction sa;
sa.sa_handler = handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART; // restart functions if interrupted by handler
sigconf(sa, flags_ = flags);
}
~Signal() noexcept(false)
{
reset_to_defaults(flags_);
}
static void reset_all_to_defaults()
{
reset_to_defaults(F_SIGINT | F_SIGTERM | F_SIGHUP | F_SIGUSR1 | F_SIGUSR2 | F_SIGPIPE);
}
static void reset_to_defaults(const unsigned int flags)
{
struct sigaction sa;
sa.sa_handler = SIG_DFL;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sigconf(sa, flags);
}
private:
static void sigconf(struct sigaction &sa, const unsigned int flags)
{
if (flags & F_SIGINT)
sigact(sa, SIGINT);
if (flags & F_SIGTERM)
sigact(sa, SIGTERM);
if (flags & F_SIGHUP)
sigact(sa, SIGHUP);
if (flags & F_SIGUSR1)
sigact(sa, SIGUSR1);
if (flags & F_SIGUSR2)
sigact(sa, SIGUSR2);
if (flags & F_SIGPIPE)
sigact(sa, SIGPIPE);
}
static void sigact(struct sigaction &sa, const int sig)
{
if (sigaction(sig, &sa, nullptr) == -1)
throw signal_error();
}
unsigned int flags_;
};
// Like Asio posix_signal_blocker, but only block certain signals
class SignalBlocker
{
SignalBlocker(const SignalBlocker &) = delete;
SignalBlocker &operator=(const SignalBlocker &) = delete;
public:
SignalBlocker(const unsigned int flags) // use signal mask from class Signal
: blocked_(false)
{
sigset_t new_mask;
sigemptyset(&new_mask);
if (flags & Signal::F_SIGINT)
sigaddset(&new_mask, SIGINT);
if (flags & Signal::F_SIGTERM)
sigaddset(&new_mask, SIGTERM);
if (flags & Signal::F_SIGHUP)
sigaddset(&new_mask, SIGHUP);
if (flags & Signal::F_SIGUSR1)
sigaddset(&new_mask, SIGUSR1);
if (flags & Signal::F_SIGUSR2)
sigaddset(&new_mask, SIGUSR2);
if (flags & Signal::F_SIGPIPE)
sigaddset(&new_mask, SIGPIPE);
blocked_ = (pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask_) == 0);
}
const sigset_t *orig_sigset() const
{
if (blocked_)
return &old_mask_;
else
return nullptr;
}
// Destructor restores the previous signal mask.
~SignalBlocker()
{
if (blocked_)
pthread_sigmask(SIG_SETMASK, &old_mask_, 0);
}
private:
// Have signals been blocked.
bool blocked_;
// The previous signal mask.
sigset_t old_mask_;
};
// Like SignalBlocker, but block specific signals in default constructor
struct SignalBlockerDefault : public SignalBlocker
{
SignalBlockerDefault()
: SignalBlocker( // these signals should be handled by parent thread
Signal::F_SIGINT
| Signal::F_SIGTERM
| Signal::F_SIGHUP
| Signal::F_SIGUSR1
| Signal::F_SIGUSR2
| Signal::F_SIGPIPE)
{
}
};
struct SignalBlockerPipe : public SignalBlocker
{
SignalBlockerPipe()
: SignalBlocker(Signal::F_SIGPIPE)
{
}
};
} // namespace openvpn
#endif
#endif
|
