Qt/Unix: Implement signal handler

Source/Core/DolphinQt2/QtUtils/SignalDaemon.cpp

@@ -0,0 +1,55 @@
+// Copyright 2018 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include "DolphinQt2/QtUtils/SignalDaemon.h"
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <QSocketNotifier>
+
+int SignalDaemon::s_sigterm_fd[2];
+
+static constexpr char message[] =
+    "\nA signal was received. A second signal will force Dolphin to stop.\n";
+
+SignalDaemon::SignalDaemon(QObject* parent) : QObject(parent)
+{
+  if (socketpair(AF_UNIX, SOCK_STREAM, 0, s_sigterm_fd))
+    qFatal("Couldn't create TERM socketpair");
+
+  m_term = new QSocketNotifier(s_sigterm_fd[1], QSocketNotifier::Read, this);
+  connect(m_term, &QSocketNotifier::activated, this, &SignalDaemon::OnNotifierActivated);
+}
+
+SignalDaemon::~SignalDaemon()
+{
+  close(s_sigterm_fd[0]);
+  close(s_sigterm_fd[1]);
+}
+
+void SignalDaemon::OnNotifierActivated()
+{
+  m_term->setEnabled(false);
+
+  char tmp;
+  if (read(s_sigterm_fd[1], &tmp, sizeof(char)))
+  {
+  }
+
+  m_term->setEnabled(true);
+
+  emit InterruptReceived();
+}
+
+void SignalDaemon::HandleInterrupt(int)
+{
+  write(STDERR_FILENO, message, sizeof(message));
+
+  char a = 1;
+  if (write(s_sigterm_fd[0], &a, sizeof(a)))
+  {
+  }
+}