metronome

#!/usr/bin/env lua
-- * Metronome IM *
--
-- This file is part of the Metronome XMPP server and is released under the
-- ISC License, please see the LICENSE file in this source package for more
-- information about copyright and licensing.

CFG_SOURCEDIR=os.getenv("METRONOME_SRCDIR");
CFG_CONFIGDIR=os.getenv("METRONOME_CFGDIR");
CFG_PLUGINDIR=os.getenv("METRONOME_PLUGINDIR");
CFG_DATADIR=os.getenv("METRONOME_DATADIR");

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

local function is_relative(path)
	local path_sep = package.config:sub(1,1);
        return ((path_sep == "/" and path:sub(1,1) ~= "/")
	or (path_sep == "\\" and (path:sub(1,1) ~= "/" and path:sub(2,3) ~= ":\\")))
end

if CFG_SOURCEDIR then
	local function filter_relative_paths(path)
		if is_relative(path) then return ""; end
	end
	local function sanitise_paths(paths)
		return (paths:gsub("[^;]+;?", filter_relative_paths):gsub(";;+", ";"));
	end
	package.path = sanitise_paths(CFG_SOURCEDIR.."/?.lua;"..package.path);
	package.cpath = sanitise_paths(CFG_SOURCEDIR.."/?.so;"..package.cpath);
end

if CFG_DATADIR then
	if os.getenv("HOME") then
		CFG_DATADIR = CFG_DATADIR:gsub("^~", os.getenv("HOME"));
	end
end

local metronome = { events = require "util.events".new(); incoming_s2s = {} };
_G.metronome = metronome;

local dependencies = require "util.dependencies";
if not dependencies.check_dependencies() then
	os.exit(1);
end

config = require "core.configmanager"

function read_config()
	local filenames = {};
	
	local filename;
	if arg[1] == "--config" and arg[2] then
		table.insert(filenames, arg[2]);
		if CFG_CONFIGDIR then
			table.insert(filenames, CFG_CONFIGDIR.."/"..arg[2]);
		end
	else
		for _, format in ipairs(config.parsers()) do
			table.insert(filenames, (CFG_CONFIGDIR or ".").."/metronome.cfg."..format);
		end
	end
	for _,_filename in ipairs(filenames) do
		filename = _filename;
		local file = io.open(filename);
		if file then
			file:close();
			CFG_CONFIGDIR = filename:match("^(.*)[\\/][^\\/]*$");
			break;
		end
	end
	local ok, level, err = config.load(filename);
	if not ok then
		print("\n");
		print("**************************");
		if level == "parser" then
			print("A problem occured while reading the config file "..(CFG_CONFIGDIR or ".").."/metronome.cfg.lua"..":");
			print("");
			local err_line, err_message = tostring(err):match("%[string .-%]:(%d*): (.*)");
			if err:match("chunk has too many syntax levels$") then
				print("An Include statement in a config file is including an already-included");
				print("file and causing an infinite loop. An Include statement in a config file is...");
			else
				print("Error"..(err_line and (" on line "..err_line) or "")..": "..(err_message or tostring(err)));
			end
			print("");
		elseif level == "file" then
			print("Metronome was unable to find the configuration file.");
			print("We looked for: "..(CFG_CONFIGDIR or ".").."/metronome.cfg.lua");
		end
		print("**************************");
		print("");
		os.exit(1);
	end
end

function files_serialization_format()
	metronome.serialization = config.get("*", "flat_files_serialization") or "internal";
end

function preload_libraries()
	local libs = config.get("*", "metronome_preload_libraries");
	libs = type(libs) ~= "table" and {} or libs;

	for _, name in ipairs(libs) do pcall(require, name); end
end

function init_net_server()
	server = require "net.server"
end	

function init_logging()
	require "core.loggingmanager"
end

function log_dependency_warnings()
	dependencies.log_warnings();
end

function sanity_check()
	for host, host_config in pairs(config.getconfig()) do
		if host ~= "*"
		and host_config.enabled ~= false
		and not host_config.component_module then
			return;
		end
	end
	log("error", "No enabled VirtualHost entries found in the config file.");
	log("error", "At least one active host is required for Metronome to function. Exiting...");
	os.exit(1);
end

function sandbox_require()
	local _realG = _G;
	local _real_require = require;
	if not getfenv then
		-- FIXME: This is a hack to replace getfenv() in Lua 5.2
		function getfenv(f) return debug.getupvalue(debug.getinfo(f or 1).func, 1); end
	end
	function require(...)
		local curr_env = getfenv(2);
		local curr_env_mt = getmetatable(curr_env);
		local _realG_mt = getmetatable(_realG);
		if curr_env_mt and curr_env_mt.__index and not curr_env_mt.__newindex and _realG_mt then
			local old_newindex, old_index;
			old_newindex, _realG_mt.__newindex = _realG_mt.__newindex, curr_env;
			old_index, _realG_mt.__index = _realG_mt.__index, function (_G, k)
				return rawget(curr_env, k);
			end;
			local ret = _real_require(...);
			_realG_mt.__newindex = old_newindex;
			_realG_mt.__index = old_index;
			return ret;
		end
		return _real_require(...);
	end
end

function set_function_metatable()
	local mt = {};
	function mt.__index(f, upvalue)
		local i, name, value = 0;
		repeat
			i = i + 1;
			name, value = debug.getupvalue(f, i);
		until name == upvalue or name == nil;
		return value;
	end
	function mt.__newindex(f, upvalue, value)
		local i, name = 0;
		repeat
			i = i + 1;
			name = debug.getupvalue(f, i);
		until name == upvalue or name == nil;
		if name then
			debug.setupvalue(f, i, value);
		end
	end
	function mt.__tostring(f)
		local info = debug.getinfo(f);
		return ("function(%s:%d)"):format(info.short_src:match("[^\\/]*$"), info.linedefined);
	end
	debug.setmetatable(function() end, mt);
end

function init_global_state()
	bare_sessions = {};
	full_sessions = {};
	hosts = {};

	metronome.bare_sessions = bare_sessions;
	metronome.full_sessions = full_sessions;
	metronome.hosts = hosts;
	
	local data_path = config.get("*", "data_path") or CFG_DATADIR or "data";
	local custom_plugin_paths = config.get("*", "plugin_paths");
	if custom_plugin_paths then
		local path_sep = package.config:sub(3,3);
		-- path1;path2;path3;defaultpath...
		CFG_PLUGINDIR = table.concat(custom_plugin_paths, path_sep)..path_sep..(CFG_PLUGINDIR or "plugins");
	end
	metronome.paths = { source = CFG_SOURCEDIR, config = CFG_CONFIGDIR or ".", 
	                  plugins = CFG_PLUGINDIR or "plugins", data = data_path };

	metronome.arg = _G.arg;

	metronome.platform = "unknown";
	if package.config:sub(1,1) == "/" then metronome.platform = "posix"; end
	
	metronome.installed = nil;
	if CFG_SOURCEDIR and CFG_SOURCEDIR:match("^/") then metronome.installed = true; end

	if metronome.installed then require "lfs".chdir(data_path); end
	
	function metronome.reload_config()
		log("info", "Reloading configuration file");
		metronome.events.fire_event("reloading-config");
		local ok, level, err = config.load((rawget(_G, "CFG_CONFIGDIR") or ".").."/metronome.cfg.lua");
		if not ok then
			if level == "parser" then
				log("error", "There was an error parsing the configuration file: %s", tostring(err));
			elseif level == "file" then
				log("error", "Couldn't read the config file when trying to reload: %s", tostring(err));
			end
		else
			metronome.set_gc();
		end
		return ok, (err and tostring(level)..": "..tostring(err)) or nil;
	end

	function metronome.reopen_logfiles()
		log("info", "Re-opening log files");
		metronome.events.fire_event("reopen-log-files");
	end

	function metronome.shutdown(reason)
		log("info", "Shutting down: %s", reason or "unknown reason");
		metronome.shutdown_reason = reason;
		metronome.events.fire_event("server-stopping", {reason = reason});
		server.setquitting(true);
	end
	
	function metronome.set_gc()
		local settings = config.get("*", "metronome_gc");
		settings = type(settings) ~= "table" and {} or settings;
		collectgarbage("setpause", settings.setpause or 100);
		collectgarbage("setstepmul", settings.setstepmul or 150);
		collectgarbage("restart");
	end
	
	local certmanager = require "util.certmanager";
	local global_ssl_ctx = certmanager.create_context("*", "server");
	metronome.global_ssl_ctx = global_ssl_ctx;
	metronome.set_gc();
end

read_version = require "util.auxiliary".read_version;
ripairs = require "util.auxiliary".ripairs;

function load_secondary_libraries()
	require "util.import";
	require "util.xmppstream";
	require "core.hostmanager";
	require "core.portmanager";
	require "core.modulemanager";
	require "core.usermanager";
	require "core.sessionmanager";

	require "net.http";
	
	require "util.array";
	require "util.datetime";
	require "util.iterators";
	require "util.timer";
	require "util.helpers";
	
	pcall(require, "util.signal");
	
	require "util.stanza";
	require "util.jid";
end

function init_data_store()
	require "core.storagemanager";
end

function prepare_to_start()
	log("info", "Metronome is using the %s backend for connection handling", server.get_backend());
	metronome.events.fire_event("server-starting");
	metronome.start_time = os.time();
end	

function init_global_protection()
	local locked_globals_mt = {
		__index = function (t, k) log("warn", "%s", debug.traceback("Attempt to read a non-existent global '"..tostring(k).."'", 2)); end;
		__newindex = function (t, k, v) error("Attempt to set a global: "..tostring(k).." = "..tostring(v), 2); end;
	};
		
	function metronome.unlock_globals()
		setmetatable(_G, nil);
	end
	
	function metronome.lock_globals()
		setmetatable(_G, locked_globals_mt);
	end

	metronome.lock_globals();
end

function loop()
	local function catch_uncaught_error(err)
		if type(err) == "string" and err:match("interrupted!$") then
			return "quitting";
		end
		
		log("error", "Top-level error, please report:\n%s", tostring(err));
		local traceback = debug.traceback("", 2);
		if traceback then
			log("error", "%s", traceback);
		end
		
		metronome.events.fire_event("very-bad-error", {error = err, traceback = traceback});
	end
	
	while select(2, xpcall(server.loop, catch_uncaught_error)) ~= "quitting" do
		socket.sleep(0.2);
	end
end

function cleanup()
	log("info", "Shutdown status: Cleaning up");
	metronome.events.fire_event("server-cleanup");
	
	server.setquitting(false);
	
	log("info", "Shutdown status: Closing all active sessions");
	for hostname, host in pairs(hosts) do
		log("debug", "Shutdown status: Closing client connections for %s", hostname)
		if host.sessions then
			local reason = { condition = "system-shutdown", text = "Server is shutting down" };
			if metronome.shutdown_reason then
				reason.text = reason.text..": "..metronome.shutdown_reason;
			end
			for username, user in pairs(host.sessions) do
				for resource, session in pairs(user.sessions) do
					log("debug", "Closing connection for %s@%s/%s", username, hostname, resource);
					session:close(reason);
				end
			end
		end
	
		log("debug", "Shutdown status: Closing outgoing s2s connections from %s", hostname);
		if host.s2sout then
			for remotehost, session in pairs(host.s2sout) do
				if session.close then
					session:close("system-shutdown");
				else
					log("warn", "Unable to close outgoing s2s session to %s, no session:close()?!", remotehost);
				end
			end
		end
	end

	log("info", "Shutdown status: Closing all server connections");
	server.closeall();
	
	server.setquitting(true);
end

read_config();
files_serialization_format();
init_logging();
sanity_check();
sandbox_require();
set_function_metatable();
preload_libraries();
init_net_server();
init_global_state();
read_version();
log("info", "Hello and welcome to Metronome version %s", metronome.version);
log_dependency_warnings();
load_secondary_libraries();
init_data_store();
init_global_protection();
prepare_to_start();

metronome.events.fire_event("server-started");

loop();

log("info", "Shutting down...");
cleanup();
metronome.events.fire_event("server-stopped");
log("info", "Shutdown complete");