Sebastian Hahn authored 9 years ago and Nick Mathewson committed 9 years ago

This includes a small refactoring to use a new enum (workqueue_reply_t)
for the return values instead of just ints.

This avoids a conflict with a macro decl from libevent 1.x.

Fixes bug 16867; bug not in any released Tor.

We don't want to accept any work after one of our worker functions has
returned WQ_RPL_SHUTDOWN. This testcase currently fails, because we do
not actually stop any of the worker threads.

Needs changes file, documentation, test integration, more tests.

This puts the init logic in a separate function, which we will need
once we have locking.

Some of them like to munge the global event mask, so it's important
to have that behavior isolated.

We used to use this when we had some controllers that would accept
long names and some that wouldn't.  But it's been obsolete for a
while, and it's time to strip it out of the code.

Previously we'd put these strings right on the controllers'
outbufs. But this could cause some trouble, for these reasons:

  1) Calling the network stack directly here would make a huge portion
     of our networking code (from which so much of the rest of Tor is
     reachable) reachable from everything that potentially generated
     controller events.

  2) Since _some_ events (EVENT_ERR for instance) would cause us to
     call connection_flush(), every control_event_* function would
     appear to be able to reach even _more_ of the network stack in
     our cllgraph.

  3) Every time we generated an event, we'd have to walk the whole
     connection list, which isn't exactly fast.

This is an attempt to break down the "blob" described in
http://archives.seul.org/tor/dev/Mar-2015/msg00197.html -- the set of
functions from which nearly all the other functions in Tor are
reachable.

Closes ticket 16695.