Use monotonic clocks for time as appropriate
In some places, like or or, we want to use wall-clock time. But in others, like timers and so forth, we should be using a monotonic timer so we just don't have to worry about time moving backwards.
Libevent 2.1 has a subsystem for this; we could just use it as needed. Or we could snarf the code and adapt it for our uses.
Activity
changed milestone to %Tor: unspecified
We came up with a simple ratcheted implementation in tor_gettimeofday_cached_monotonic. Doing the right thing here will be a bit tricky, given how we need to cache times here too, so I think we're okay deferring to 0.2.6.
(For an overview of how complicated the right thing is here, peruse Libevent's https://github.com/libevent/libevent/blob/master/evutil_time.c )
Trac:
Milestone: Tor: 0.2.5.x-final to Tor: 0.2.6.x-final-
A thought: these should not use timeval or time_t, but rather should use a new set of structs, eg
typedef monotime_s { time_t t; } monotime_t; typedef monotimeval_s { struct timeval tv; } monotimeval_t; ...This will help us make the code safe, since the timevals that you get from clock_gettime() do not necessarily correspond to the ones you get from gettimeofday().