util.signal: Fix signalfd closure on non-Linux systems The loop was incorrect for 0-indexed arrays. It started at signalfd_num, which is the total number of signalfds, and decremented to 1 (condition was >0). So if 1 signalfd was registered, it would check only signalfds[1]. At capacity (32 signalfds) it would read past the end of the array. In every case, it would always skip the entry at position [0], leading to a leak. The swap-with-tail removal of the matched item used the post-decrement operator, leading to accessing the array slot just beyond the tail. Finally, it didn't break after finding a match. Probably harmless, but there isn't expected to be more than a single entry per fd, as far as I can tell.

-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local host = module:get_host();
local welcome_text = module:get_option_string("welcome_message", "Hello $username, welcome to the $host IM server!");

local st = require "prosody.util.stanza";

module:hook("user-registered",
	function (user)
		local welcome_stanza =
			st.message({ to = user.username.."@"..user.host, from = host },
				welcome_text:gsub("$(%w+)", user));
		module:send(welcome_stanza);
		module:log("debug", "Welcomed user %s@%s", user.username, user.host);
	end);