Add basic token system to log in IRC

- Tokens are generated/removed ingame
 - Everytime a token is (re)generated/removed anybody logged in using this player's login
   will be logged off IRC

mods/irc_commands/init.lua

@@ -1,5 +1,7 @@
 
 local irc_users = {}
+local irc_tokens = {}
+local tokens_file = minetest.get_worldpath() .. "/irc_tokens"
 
 local old_chat_send_player = minetest.chat_send_player
 minetest.chat_send_player = function(name, message)
@@ -11,6 +13,94 @@ minetest.chat_send_player = function(name, message)
 	return old_chat_send_player(name, message)
 end
 
+-- Load/Save tokens
+local function load_tokens()
+	local f = io.open(tokens_file, "r")
+	local tokens = {}
+	if f then
+		tokens = minetest.deserialize(f:read())	
+		f:close()
+	end
+	return tokens
+end
+irc_tokens = load_tokens()
+
+local function save_tokens()
+	local f = io.open(tokens_file, "w")
+	if f then
+		f:write(minetest.serialize(irc_tokens))
+		f:close()
+		return true
+	else
+		minetest.log("error", "[IRC_Commands] Tokens storage file couldn't be created!")
+		return false
+	end
+end
+
+local function generate_token(name)
+	local passtr = ""
+	for i = 1, math.random(20,40) do
+		passtr = passtr .. tostring(math.random(1,65535))
+	end
+	return minetest.get_password_hash(name, passtr)
+end
+
+-- Note: You can and **should** regulary regenerate tokens
+minetest.register_chatcommand("gen_token", {
+	description = "Generate irc token to log in",
+	privs = {shout = true},
+	func = function(name, param)
+		if not minetest.get_player_by_name(name) then
+			return false, "You need to be logged in to the server to generate tokens"
+		end
+		local h = ""
+		if irc_tokens[name] then
+			h = " new"
+		end
+		irc_tokens[name] = generate_token(name)
+		minetest.chat_send_player(name, "Here is you" .. h .. " token : " .. irc_tokens[name])
+		save_tokens()
+
+		-- Disconnect any user using this login
+		for nick, loggedInAs in pairs(irc_users) do
+			if loggedInAs == name then
+				minetest.log("action", nick.."@IRC has been logged out from "
+					..irc_users[nick] .. " (token regenerated)")
+				irc_users[nick] = nil
+				irc:say(nick, "Token regenerated. You are now logged off.")
+			end		
+		end
+		return true
+	end
+})
+
+minetest.register_chatcommand("del_token", {
+	description = "Delete your entry in the token register",
+	privs = {shout = true},
+	func = function(name)
+		if not minetest.get_player_by_name(name) then
+			return false, "You need to be logged in to the server to generate tokens"
+		end
+		if not irc_tokens[name] then
+			return true, "You had no entry in the tokens' register"
+		else
+			irc_tokens[name] = nil
+			save_tokens()
+			-- Disconnect any user using this login
+			for nick, loggedInAs in pairs(irc_users) do
+				if loggedInAs == name then
+					minetest.log("action", nick.."@IRC has been logged out from "
+						..irc_users[nick] .. " (token regenerated)")
+					irc_users[nick] = nil
+					irc:say(nick, "Token regenerated. You are now logged off.")
+				end		
+			end
+			return true, "Access for you using a token has been removed. Use /gen_token to create" ..
+				" a new token at any time"
+		end
+	end
+})
+
 irc:register_hook("NickChange", function(user, newNick)
 	for nick, player in pairs(irc_users) do
 		if nick == user.nick then
@@ -32,6 +122,46 @@ irc:register_hook("OnQuit", function(user, reason)
 	irc_users[user.nick] = nil
 end)
 
+
+-- Pretty much a copypasta of the command right after this one
+-- We'll keep "login" until passwords are broken. When it happens,
+-- We'll remove "tlogin" and modify "login" to handle tokens
+irc:register_bot_command("tlogin", {
+	params = "<username> <pass_token>",
+	description = "Login as an user to run commands, using a token",
+	func = function(user, args)
+		if args == "" then
+			return false, "You need a username and a token."
+		end
+		local playerName, token = args:match("^(%S+)%s(%S+)$")
+		if not playerName then
+			return false, "Player name and password required."
+		end
+		local inChannel = false
+		local users = irc.conn.channels[irc.config.channel].users
+		for cnick, cuser in pairs(users) do
+			if user.nick == cnick then
+				inChannel = true
+				break
+			end
+		end
+		if not inChannel then
+			return false, "You need to be in the server's channel to login."
+		end
+		if irc_tokens[playerName] and
+			irc_tokens[playerName] == token then
+			minetest.log("action", "User " .. user.nick
+					.." from IRC logs in as " .. playerName .. " using their token")
+			irc_users[user.nick] = playerName
+			return true, "You are now logged in as " .. playerName
+		else
+			minetest.log("action", user.nick.."@IRC attempted to log in as "
+				..playerName.." unsuccessfully using a token")
+			return false, "Incorrect token or player does not exist."
+		end
+	end
+})
+
 irc:register_bot_command("login", {
 	params = "<username> <password>",
 	description = "Login as a user to run commands",