Do we really need to run retry_listeners_callback so often?

[nickm]

We run this function once a minute -- but, why? Do listeners really go away and need to be relaunched?

[dgoulet]

Function comment says:

 * Periodic callback: Every 60 seconds, we relaunch listeners if any died. */

I'm not sure how a listener can die?... but let say the ORPort 443 does die for some obscure reasons (which I would assume something close() it), then even retrying to listen on 443 will fail because tor will in most cases have changed UID (setuid()).

Listeners can change within our torrc options (or control port) but we do retry them all explicitly.

Thus, I have _no_ clue why tor would retry to listen regularly... Is it something that Windows could do as in kill listener fd for weird reasons...?

I think that if such a thing would be possible, we should catch it in the poll() and then recover from there, not a callback that arbitrarily retries.