util.signal: Add support for signalfd(2) on Linux
signalfd allows handling signal events using the same method as sockets,
via file descriptors. Thus all signal dispatch can go through the same
main event loop as everything else, removing need for thread-scary
signal handling where execution would just jump to the signal handler
regardless of the state of Lua, and needing to keep track of Lua
states/threads.
module:set_global();
local array = require "prosody.util.array";
local max_buffer_len = module:get_option_integer("multiplex_buffer_size", 1024, 1);
local default_mode = module:get_option_integer("network_default_read_size", 4096, 0);
local portmanager = require "prosody.core.portmanager";
local available_services = {};
local service_by_protocol = {};
local available_protocols = array();
local function add_service(service)
local multiplex_pattern = service.multiplex and service.multiplex.pattern;
local protocol_name = service.multiplex and service.multiplex.protocol;
if protocol_name then
module:log("debug", "Adding multiplex service %q with protocol %q", service.name, protocol_name);
service_by_protocol[protocol_name] = service;
available_protocols:push(protocol_name);
end
if multiplex_pattern then
module:log("debug", "Adding multiplex service %q with pattern %q", service.name, multiplex_pattern);
available_services[service] = multiplex_pattern;
elseif not protocol_name then
module:log("debug", "Service %q is not multiplex-capable", service.name);
end
end
module:hook("service-added", function (event) add_service(event.service); end);
module:hook("service-removed", function (event)
available_services[event.service] = nil;
if event.service.multiplex and event.service.multiplex.protocol then
available_protocols:filter(function (p) return p ~= event.service.multiplex.protocol end);
service_by_protocol[event.service.multiplex.protocol] = nil;
end
end);
for _, services in pairs(portmanager.get_registered_services()) do
for _, service in ipairs(services) do
add_service(service);
end
end
local buffers = {};
local listener = { default_mode = max_buffer_len };
function listener.onconnect(conn)
local sock = conn:socket();
if sock.getalpn then
local selected_proto = sock:getalpn();
local service = service_by_protocol[selected_proto];
if service then
module:log("debug", "Routing incoming connection to %s based on ALPN %q", service.name, selected_proto);
local next_listener = service.listener;
conn:setlistener(next_listener);
conn:set_mode(next_listener.default_mode or default_mode);
local onconnect = next_listener.onconnect;
if onconnect then return onconnect(conn) end
end
end
end
function listener.onincoming(conn, data)
if not data then return; end
local buf = buffers[conn];
buf = buf and buf..data or data;
for service, multiplex_pattern in pairs(available_services) do
if buf:match(multiplex_pattern) then
module:log("debug", "Routing incoming connection to %s", service.name);
local next_listener = service.listener;
conn:setlistener(next_listener);
conn:set_mode(next_listener.default_mode or default_mode);
local onconnect = next_listener.onconnect;
if onconnect then onconnect(conn) end
return next_listener.onincoming(conn, buf);
end
end
if #buf > max_buffer_len then -- Give up
conn:close();
else
buffers[conn] = buf;
end
end
function listener.ondisconnect(conn)
buffers[conn] = nil; -- warn if no buffer?
end
listener.ondetach = listener.ondisconnect;
module:provides("net", {
name = "multiplex";
config_prefix = "";
listener = listener;
});
module:provides("net", {
name = "multiplex_ssl";
config_prefix = "ssl";
encryption = "ssl";
ssl_config = {
alpn = function ()
return available_protocols;
end;
};
listener = listener;
});