add a signal handler

stepmania/src/archutils/Unix/SignalHandler.cpp

@@ -0,0 +1,76 @@
+#include "global.h"
+
+#include "RageLog.h"
+#include "SignalHandler.h"
+
+#include <unistd.h>
+
+static vector<SignalHandler::handler> handlers;
+SaveSignals *saved_sigs;
+static bool initted = false;
+
+static int signals[] = {
+	SIGALRM, SIGBUS, SIGFPE, SIGHUP, SIGILL, SIGINT, SIGIOT, SIGPIPE,
+	SIGPWR, SIGQUIT, SIGSEGV, SIGTRAP, SIGTERM, SIGVTALRM, SIGXCPU, SIGXFSZ,
+	-1
+};
+
+/*
+ * Store signals and restore them.  This lets us clean up after libraries
+ * that like to mess with our signal handler.  (Of course, if we undo
+ * signal handlers for libraries, we need to be sure to handle whatever it
+ * was cleaning up by hand.)
+ */
+
+SaveSignals::SaveSignals()
+{
+	/* Store the old signal handlers. */
+	for(int i = 0; signals[i] != -1; ++i)
+	{
+        old_handlers.push_back();
+		sigaction(signals[i], NULL, &old_handlers.back());
+	}
+}
+
+SaveSignals::~SaveSignals()
+{
+	/* Restore the old signal handlers. */
+	for(unsigned i = 0; i < old_handlers.size(); ++i)
+		sigaction(signals[i], &old_handlers[i], NULL);
+}
+
+static void SigHandler(int sig)
+{
+	LOG->Trace("got sig %i", sig);
+	for(unsigned i = 0; i < handlers.size(); ++i)
+		handlers[i](sig);
+
+	_exit(1);
+}
+
+/* Hook up events to fatal signals, so we can clean up if we're killed. */
+void SignalHandler::OnClose(handler h)
+{
+	if(saved_sigs == NULL)
+	{
+		saved_sigs = new SaveSignals;
+
+		/* Set up our signal handlers. */
+		for(int i = 0; signals[i] != -1; ++i)
+		{
+			struct sigaction sa;
+
+			sa.sa_handler = SigHandler;
+			sa.sa_flags = 0;
+			sigemptyset(&sa.sa_mask);
+
+			sigaction(signals[i], &sa, NULL);
+		}
+	}
+	handlers.push_back(h);
+}
+
+
+/* Written by Glenn Myanard.  Public domain, copyrighting a simple signal handler
+ * is dumb. */
+

stepmania/src/archutils/Unix/SignalHandler.h

@@ -0,0 +1,25 @@
+#ifndef SIGNAL_HANDLER_H
+#define SIGNAL_HANDLER_H
+
+#include <signal.h>
+       
+class SaveSignals
+{
+	vector<struct sigaction> old_handlers;
+
+public:
+	SaveSignals(); /* save signals */
+	~SaveSignals(); /* restore signals */
+};
+
+namespace SignalHandler
+{
+	typedef void (*handler)(int);
+
+	void OnClose(handler);
+};
+
+#endif
+
+/* Written by Glenn Maynard.  Public domain. */
+