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/*
* Copyright (C) 2003-2013 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "SignalMonitor.hxx"
#ifndef WIN32
#include "WakeFD.hxx"
#include "SocketMonitor.hxx"
#include "util/Manual.hxx"
#include "system/FatalError.hxx"
#include <atomic>
#include <algorithm>
class SignalMonitor final : private SocketMonitor {
WakeFD fd;
public:
SignalMonitor(EventLoop &_loop)
:SocketMonitor(_loop) {
SocketMonitor::Open(fd.Get());
SocketMonitor::ScheduleRead();
}
~SignalMonitor() {
/* prevent the descriptor to be closed twice */
SocketMonitor::Steal();
}
void WakeUp() {
fd.Write();
}
private:
virtual bool OnSocketReady(unsigned flags) override;
};
/* this should be enough - is it? */
static constexpr unsigned MAX_SIGNAL = 64;
static SignalHandler signal_handlers[MAX_SIGNAL];
static std::atomic_bool signal_pending[MAX_SIGNAL];
static Manual<SignalMonitor> monitor;
static void
SignalCallback(int signo)
{
assert(signal_handlers[signo] != nullptr);
if (!signal_pending[signo].exchange(true))
monitor->WakeUp();
}
void
SignalMonitorInit(EventLoop &loop)
{
monitor.Construct(loop);
}
static void
x_sigaction(int signum, const struct sigaction &act)
{
if (sigaction(signum, &act, nullptr) < 0)
FatalSystemError("sigaction() failed");
}
void
SignalMonitorFinish()
{
struct sigaction sa;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_DFL;
for (unsigned i = 0; i < MAX_SIGNAL; ++i) {
if (signal_handlers[i] != nullptr) {
x_sigaction(i, sa);
signal_handlers[i] = nullptr;
}
}
std::fill_n(signal_pending, MAX_SIGNAL, false);
monitor.Destruct();
}
void
SignalMonitorRegister(int signo, SignalHandler handler)
{
assert(signal_handlers[signo] == nullptr);
assert(!signal_pending[signo]);
signal_handlers[signo] = handler;
struct sigaction sa;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
sa.sa_handler = SignalCallback;
x_sigaction(signo, sa);
}
bool
SignalMonitor::OnSocketReady(unsigned)
{
fd.Read();
for (unsigned i = 0; i < MAX_SIGNAL; ++i)
if (signal_pending[i].exchange(false))
signal_handlers[i]();
return true;
}
#endif
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