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-rw-r--r--src/event/SignalMonitor.cxx133
1 files changed, 133 insertions, 0 deletions
diff --git a/src/event/SignalMonitor.cxx b/src/event/SignalMonitor.cxx
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--- /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 <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