UnixSocketServer.cpp

// Aleth: Ethereum C++ client, tools and libraries.
// Copyright 2015-2019 Aleth Authors.
// Licensed under the GNU General Public License, Version 3.

#if !defined(_WIN32)

#include "UnixSocketServer.h"
#include <sys/socket.h>
#include <fcntl.h>
#include <unistd.h>
#include <libdevcore/Guards.h>
#include <libdevcore/FileSystem.h>
#include <boost/filesystem/path.hpp>

// "Mac OS X does not support the flag MSG_NOSIGNAL but we have an equivalent."
// See http://lists.apple.com/archives/macnetworkprog/2002/Dec/msg00091.html
#if defined(__APPLE__)
	#if !defined(MSG_NOSIGNAL)
		#define MSG_NOSIGNAL SO_NOSIGPIPE
	#endif
#endif

using namespace std;
using namespace jsonrpc;
using namespace dev;
namespace fs = boost::filesystem;

namespace
{
size_t const c_socketPathMaxLength = sizeof(sockaddr_un::sun_path) / sizeof(sockaddr_un::sun_path[0]) - 1;

fs::path getIpcPathOrDataDir()
{
	// On Unix use datadir as default IPC path.
	fs::path path = getIpcPath();
	if (path.empty())
		return getDataDir();
	return path;
}
}

UnixDomainSocketServer::UnixDomainSocketServer(string const& _appId):
	IpcServerBase((getIpcPathOrDataDir() / fs::path(_appId + ".ipc")).string().substr(0, c_socketPathMaxLength))
{
}

UnixDomainSocketServer::~UnixDomainSocketServer()
{
	StopListening();
}

bool UnixDomainSocketServer::StartListening()
{
	if (!m_running)
	{
		if (access(m_path.c_str(), F_OK) != -1)
			unlink(m_path.c_str());

		if (access(m_path.c_str(), F_OK) != -1)
			return false;

		m_socket = socket(PF_UNIX, SOCK_STREAM, 0);
		memset(&(m_address), 0, sizeof(sockaddr_un));
		m_address.sun_family = AF_UNIX;
#ifdef __APPLE__
		m_address.sun_len = m_path.size() + 1;
#endif
		strncpy(m_address.sun_path, m_path.c_str(), c_socketPathMaxLength);
		::bind(m_socket, reinterpret_cast<sockaddr*>(&m_address), sizeof(sockaddr_un));
		fs::permissions(m_path, fs::owner_read | fs::owner_write);
		listen(m_socket, 128);
	}
	return IpcServerBase::StartListening();
}

bool UnixDomainSocketServer::StopListening()
{
	shutdown(m_socket, SHUT_RDWR);
	close(m_socket);
	m_socket = -1;
	if (IpcServerBase::StopListening())
	{
		unlink(m_path.c_str());
		return true;
	}
	return false;
}

void UnixDomainSocketServer::Listen()
{
	socklen_t addressLen = sizeof(m_address);
	while (m_running)
	{
		int connection = accept(m_socket, (sockaddr*) &(m_address), &addressLen);
		if (connection > 0)
		{
			DEV_GUARDED(x_sockets)
				m_sockets.insert(connection);

			// Handle the request in a new detached thread.
			std::thread{[this, connection]
			{
				GenerateResponse(connection);
				CloseConnection(connection);
			}}.detach();
		}
	}
}

void UnixDomainSocketServer::CloseConnection(int _socket)
{
	shutdown(_socket, SHUT_RDWR);
	close(_socket);
}


size_t UnixDomainSocketServer::Write(int _connection, string const& _data)
{
	ssize_t r = send(_connection, _data.data(), _data.size(), MSG_NOSIGNAL);
	if (r < 0)
		return 0;
	return static_cast<size_t>(r);
}

size_t UnixDomainSocketServer::Read(int _connection, void* _data, size_t _size)
{
	ssize_t r = read(_connection, _data, _size);
	if (r < 0)
		return 0;
	return static_cast<size_t>(r);
}

#endif