-- Monkeypatch to support socket activation

--

-- Requires LuaSocket after "agnostic" changes merged

--

-- To enable:

-- RunScript "socket-activation.lua"

local socket = require"socket";

local tcp_serv_mt = debug.getregistry()["tcp{server}"];

local socket_bind = socket.bind;

local SD_LISTEN_FDS_START = 3;

local fds = tonumber(os.getenv"LISTEN_FDS") or 0;

if fds < SD_LISTEN_FDS_START then return; end

local servs = {};

for i = 1, fds do

	local serv = socket.tcp();

	if serv:getfd() >= 0 then

		return; -- This won't work, we will leak the old FD

	end

	debug.setmetatable(serv, tcp_serv_mt);

	serv:setfd(SD_LISTEN_FDS_START + i - 1);

	local ip, port = serv:getsockname();

	servs [ ip .. ":" .. port ] = serv;

end

function socket.bind( ip, port, backlog )

	local sock = servs [ ip .. ":" .. port ];

	if sock then

		servs [ ip .. ":" .. port ] = nil;

		return sock;

	end

	if next(servs) == nil then

		-- my work here is done

		socket.bind = socket_bind;

	end

	return socket_bind( ip, port, backlog );

end