AlarmServer/server.cpp

#include <boost/bind.hpp>
#include <boost/make_shared.hpp>
#include <iostream>
#include <sys/wait.h>

#include "server.h"

server::server(boost::asio::io_service& ioService, unsigned short port, const std::string& path, const std::string& url) :
	m_ioService(ioService),
	m_signal(ioService, SIGCHLD),
	m_acceptor(ioService, boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port)),
	m_socket(ioService)
{
	m_context.path = path;
	m_context.url = url;

	start_signal_wait();
	start_accept();
}

void server::start_signal_wait()
{
	m_signal.async_wait(boost::bind(&server::handle_signal_wait, this));
}

void server::handle_signal_wait()
{
	// Only the parent process should check for this signal. We can determine
	// whether we are in the parent by checking if the acceptor is still open.
	if (m_acceptor.is_open())
	{
		// Reap completed child processes so that we don't end up with zombies.
		int status = 0;
		while (waitpid(-1, &status, WNOHANG) > 0) {}

		start_signal_wait();
	}
}

void server::start_accept()
{
	m_connection.reset(new connection(m_ioService, m_context));
	m_acceptor.async_accept(m_connection->socket(), boost::bind(&server::handle_accept, this, _1));
}

void server::handle_accept(const boost::system::error_code& ec)
{
	if (!ec)
	{
		m_ioService.notify_fork(boost::asio::io_service::fork_prepare);

		if (fork() == 0)
		{
			m_ioService.notify_fork(boost::asio::io_service::fork_child);
			m_acceptor.close();
			m_signal.cancel();

			m_connection->start();
		}
		else
		{
			m_ioService.notify_fork(boost::asio::io_service::fork_parent);

			m_connection.reset();
			m_socket.close();
			start_accept();
		}
	}
	else
	{
		std::cout << "Accept error: " << ec.message() << std::endl;
		start_accept();
	}
}