/*
 # Copyright (c) 2009 - OpenSLX Project, Computer Center University of Freiburg
 #
 # This program is free software distributed under the GPL version 2.
 # See http://openslx.org/COPYING
 #
 # If you have any feedback please consult http://openslx.org/feedback and
 # send your suggestions, praise, or complaints to feedback@openslx.org
 #
 # General information about OpenSLX can be found at http://openslx.org/
 # --------------------------------------------------------------------------
 # pvsPrivInputHandler.h
 #  - Handle privileged input connection requests - implementation
 # --------------------------------------------------------------------------
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <cerrno>
#include <QtDebug>
#include <QSocketNotifier>
#include "inputEvent.h"
#include "inputHandlerChains.h"
#include "pvsPrivInputSocket.h"
#include "pvsPrivInputHandler.h"

using namespace std;

class PrivInputContext : public InputEventContext
{
public:
	PrivInputContext(pid_t pid, uid_t uid, gid_t gid)
		: _pid(pid), _uid(uid), _gid(gid)
	{
	}

	pid_t senderPid() const
	{
		return _pid;
	}

	uid_t senderUid() const
	{
		return _uid;
	}

	gid_t senderGid() const
	{
		return _gid;
	}

private:
	pid_t _pid;
	uid_t _uid;
	gid_t _gid;
};

PVSPrivInputHandler::PVSPrivInputHandler(int fd, QObject* parent) :
	QObject(parent)
{
	_fd = fd;
	_notifier = new QSocketNotifier(fd, QSocketNotifier::Read, this);
	_notifier->setEnabled(true);
	connect(_notifier, SIGNAL(activated(int)), this, SLOT(canRead()));
	_handlerChain = makePrivilegedInputEventHandlerChain();
}

PVSPrivInputHandler::~PVSPrivInputHandler()
{
	delete _notifier;
}

void PVSPrivInputHandler::canRead()
{
	_notifier->setEnabled(false);

	// We need to retrieve the credentials of the process:
	size_t siz = 8;
	_messageAssembly.clear();
	_messageAssembly.resize(8);
	pid_t pid;
	uid_t uid;
	gid_t gid;
	int err;

	if(!pvsPrivInputRecvMessage(_fd, _messageAssembly.data(), siz, pid, uid, gid, &err))
	{
		switch(err)
		{
		case EAGAIN:
#if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
		case EWOULDBLOCK:
#endif
			// That's okay. Nothing to do.
			break;
		case 0:
			// We'll survive. There was no actual error, just the library routine
			// that decided it did not really want to receive that packet.
			break;
		default:
			qWarning("Something bad just happened, and cannot handle it. Panicking.");
			close(_fd);
			deleteLater();
			return;
		}
	}
	else
	{
		if(siz != 8)
		{
			qWarning("Malformed PVS Input Event packet");
			return;
		}
		QDataStream strm(&_messageAssembly, QIODevice::ReadOnly);
		InputEvent evt;
		strm.setByteOrder(QDataStream::BigEndian);
		strm >> evt;
		PrivInputContext ctx(pid, uid, gid);
		_handlerChain.handle(evt, &ctx);
	}

	_notifier->setEnabled(true);
}