From 930128a7ea11f7012131c4801b86b9b98a7aa9fb Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Tue, 6 Aug 2013 21:31:59 +0200 Subject: SignalHandlers: move code to new class SignalMonitor --- src/event/SignalMonitor.cxx | 133 ++++++++++++++++++++++++++++++++++++++++++++ src/event/SignalMonitor.hxx | 64 +++++++++++++++++++++ 2 files changed, 197 insertions(+) create mode 100644 src/event/SignalMonitor.cxx create mode 100644 src/event/SignalMonitor.hxx (limited to 'src/event') diff --git a/src/event/SignalMonitor.cxx b/src/event/SignalMonitor.cxx new file mode 100644 index 000000000..172b47f55 --- /dev/null +++ b/src/event/SignalMonitor.cxx @@ -0,0 +1,133 @@ +/* + * 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 +#include + +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 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 diff --git a/src/event/SignalMonitor.hxx b/src/event/SignalMonitor.hxx new file mode 100644 index 000000000..94ab0aa30 --- /dev/null +++ b/src/event/SignalMonitor.hxx @@ -0,0 +1,64 @@ +/* + * 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. + */ + +#ifndef MPD_SOCKET_SIGNAL_MONITOR_HXX +#define MPD_SOCKET_SIGNAL_MONITOR_HXX + +#include "check.h" + +class EventLoop; + +#ifndef WIN32 + +typedef void (*SignalHandler)(); + +/** + * Initialise the signal monitor subsystem. + */ +void +SignalMonitorInit(EventLoop &loop); + +/** + * Deinitialise the signal monitor subsystem. + */ +void +SignalMonitorFinish(); + +/** + * Register a handler for the specified signal. The handler will be + * invoked in a safe context. + */ +void +SignalMonitorRegister(int signo, SignalHandler handler); + +#else + +static inline void +SignalMonitorInit(EventLoop &) +{ +} + +static inline void +SignalMonitorFinish() +{ +} + +#endif + +#endif /* MAIN_NOTIFY_H */ -- cgit v1.2.3