mod_posix: Move everything to util.startup
This allows greater control over the order of events.
Notably, the internal ordering between daemonization, initialization of
libunbound and setup of signal handling is sensitive.
libunbound starts a separate thread for processing DNS requests.
If this thread is started before signal handling has been set up, it
will not inherit the signal handlers and instead behave as it would have
before signal handlers were set up, i.e. cause the whole process to
immediately exit.
libunbound is usually initialized on the first DNS request, usually
triggered by an outgoing s2s connection attempt.
If daemonization happens before signals have been set up, signals may
not be processed at all.
Structure of a session:
session {
-- properties --
conn -- the tcp connection
notopen -- true if stream has not been initiated, removed after receiving <stream:steam>
type -- the connection type. Valid values include:
-- "c2s_unauthed" - connection has not been authenticated yet
-- "c2s" - from a local client to the server
username -- the node part of the client's jid (not defined before auth)
host -- the host part of the client's jid (not defined before stream initiation)
resource -- the resource part of the client's full jid (not defined before resource binding)
full_jid -- convenience for the above 3 as string in username@host/resource form (not defined before resource binding)
priority -- the resource priority, default: 0
presence -- the last non-directed presence with no type attribute. initially nil. reset to nil on unavailable presence.
interested -- true if the resource requested the roster. Interested resources receive roster updates. Initially nil.
roster -- the user's roster. Loaded as soon as the resource is bound (session becomes a connected resource).
-- methods --
send(x) -- converts x to a string, and writes it to the connection
close(x) -- Disconnect the user and clean up the session, best call sessionmanager.destroy_session() instead of this in most cases
}
if session.full_jid (also session.roster and session.resource) then this is a "connected resource"
if session.presence then this is an "available resource" (all available resources are connected resources)
if session.interested then this is an "interested resource" (all interested resources are connected resources)