net.server_epoll: Add support for systemd socket activation
Allows creating listening sockets and accepting client connections
before Prosody starts.
This is unlike normal Prosody dynamic resource management, where ports
may added and removed at any time, and the ports defined by the config.
Weird things happen if these are closed (e.g. due to reload) so here we
prevent closing and ensure sockets are reused when opened again.
-- TODO warn when trying to create an user before the tombstone expires
-- e.g. via telnet or other admin interface
local datetime = require "prosody.util.datetime";
local errors = require "prosody.util.error";
local jid_node = require"prosody.util.jid".node;
local st = require "prosody.util.stanza";
-- Using a map store as key-value store so that removal of all user data
-- does not also remove the tombstone, which would defeat the point
local graveyard = module:open_store(nil, "map");
local graveyard_cache = require "prosody.util.cache".new(module:get_option_integer("tombstone_cache_size", 1024, 1));
local ttl = module:get_option_period("user_tombstone_expiry", nil);
-- Keep tombstones forever by default
--
-- Rationale:
-- There is no way to be completely sure when remote services have
-- forgotten and revoked all memberships.
-- TODO If the user left a JID they moved to, return a gone+redirect error
-- TODO Attempt to deregister from MUCs based on bookmarks
-- TODO Unsubscribe from pubsub services if a notification is received
module:hook_global("user-deleted", function(event)
if event.host == module.host then
local ok, err = graveyard:set(nil, event.username, os.time());
if not ok then module:log("error", "Could store tombstone for %s: %s", event.username, err); end
end
end);
-- Public API
function has_tombstone(username)
local tombstone;
-- Check cache
local cached_result = graveyard_cache:get(username);
if cached_result == false then
-- We cached that there is no tombstone for this user
return false;
elseif cached_result then
tombstone = cached_result;
else
local stored_result, err = graveyard:get(nil, username);
if not stored_result and not err then
-- Cache that there is no tombstone for this user
graveyard_cache:set(username, false);
return false;
elseif err then
-- Failed to check tombstone status
return nil, err;
end
-- We have a tombstone stored, so let's continue with that
tombstone = stored_result;
end
-- Check expiry
if ttl and tombstone + ttl < os.time() then
module:log("debug", "Tombstone for %s created at %s has expired", username, datetime.datetime(tombstone));
graveyard:set(nil, username, nil);
graveyard_cache:set(username, nil); -- clear cache entry (if any)
return nil;
end
-- Cache for the future
graveyard_cache:set(username, tombstone);
return tombstone;
end
module:hook("user-registering", function(event)
local tombstone, err = has_tombstone(event.username);
if err then
event.allowed, event.error = errors.coerce(false, err);
return true;
elseif not tombstone then
-- Feel free
return;
end
module:log("debug", "Tombstone for %s created at %s", event.username, datetime.datetime(tombstone));
event.allowed = false;
return true;
end);
module:hook("presence/bare", function(event)
local origin, presence = event.origin, event.stanza;
local local_username = jid_node(presence.attr.to);
if not local_username then return; end
-- We want to undo any left-over presence subscriptions and notify the former
-- contact that they're gone.
--
-- FIXME This leaks that the user once existed. Hard to avoid without keeping
-- the contact list in some form, which we don't want to do for privacy
-- reasons. Bloom filter perhaps?
local pres_type = presence.attr.type;
local is_probe = pres_type == "probe";
local is_normal = pres_type == nil or pres_type == "unavailable";
if is_probe and has_tombstone(local_username) then
origin.send(st.error_reply(presence, "cancel", "gone", "User deleted"));
origin.send(st.presence({ type = "unsubscribed"; to = presence.attr.from; from = presence.attr.to }));
return true;
elseif is_normal and has_tombstone(local_username) then
origin.send(st.error_reply(presence, "cancel", "gone", "User deleted"));
origin.send(st.presence({ type = "unsubscribe"; to = presence.attr.from; from = presence.attr.to }));
return true;
end
end, 1);