/***************************************************************************
 *   Copyright (C) 2010 by Joris Guisson                                   *
 *   joris.guisson@gmail.com                                               *
 *                                                                         *
 *   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 "signalcatcher.h"
#include <klocalizedstring.h>
#include <sys/socket.h>
#include <unistd.h>
#include "log.h"

#ifndef Q_WS_WIN

namespace bt
{
	sigjmp_buf sigbus_env;
	static bool siglongjmp_safe = false;
	
	static void sigbus_handler(int sig, siginfo_t *siginfo, void *ptr)
	{
		Q_UNUSED(siginfo);
		Q_UNUSED(ptr);
		Q_UNUSED(sig);
		// Jump to error handling code,
		// ignore signal if we are not safe to jump
		if (siglongjmp_safe)
			siglongjmp(sigbus_env, 1);
	}
	
	static bool InstallBusHandler()
	{
		struct sigaction act;
		
		memset(&act, 0, sizeof(act));
		
		if (sigaction(SIGBUS, 0, &act) != -1 && act.sa_sigaction == sigbus_handler)
			return true;
		
		
		act.sa_sigaction = sigbus_handler;
		act.sa_flags = SA_SIGINFO;
		
		if (sigaction(SIGBUS, &act, 0) == -1) 
		{
			Out(SYS_GEN|LOG_IMPORTANT) << "Failed to set SIGBUS handler" << endl;
			return false;
		}
		
		return true;
	}
	
	BusErrorGuard::BusErrorGuard()
	{
		InstallBusHandler();
		siglongjmp_safe = true;
	}
	
	BusErrorGuard::~BusErrorGuard()
	{
		siglongjmp_safe = false;
	}


	
	BusError::BusError(bool write_operation) 
		: Error(write_operation ? i18n("Error when writing to disk") : i18n("Error when reading from disk")),
		write_operation(write_operation)
	{

	}
	
	BusError::~BusError()
	{

	}

	int SignalCatcher::signal_received_pipe[2];

	SignalCatcher::SignalCatcher(QObject* parent) 
		: QObject(parent),
		notifier(0)
	{
		socketpair(AF_UNIX, SOCK_STREAM, 0, signal_received_pipe);
		notifier = new QSocketNotifier(signal_received_pipe[1], QSocketNotifier::Read, this);
		connect(notifier, SIGNAL(activated(int)), this, SLOT(handleInput(int)));
	}

	SignalCatcher::~SignalCatcher()
	{
	}
	
	void SignalCatcher::signalHandler(int sig, siginfo_t* siginfo, void* ptr)
	{
		Q_UNUSED(siginfo);
		Q_UNUSED(ptr);
		::write(signal_received_pipe[0], &sig, sizeof(int));
	}

	
	bool SignalCatcher::catchSignal(int sig)
	{
		struct sigaction act;
		memset(&act, 0, sizeof(act));	
		act.sa_sigaction = SignalCatcher::signalHandler;
		act.sa_flags = SA_SIGINFO;
		
		if (sigaction(sig, &act, 0) == -1) 
		{
			Out(SYS_GEN|LOG_IMPORTANT) << "Failed to set signal handler for " << sig << endl;
			return false;
		}
		
		return true;
	}

	void SignalCatcher::handleInput(int fd)
	{
		int sig = 0;
		::read(fd, &sig, sizeof(int));
		
		Out(SYS_GEN|LOG_IMPORTANT) << "Signal " <<  sig << " caught " << endl;
		Q_EMIT triggered();
	}


}

#endif
