TorCtl doesn't expand relative paths
Mike asked for me to file tickets for the issues I've encountered with TorCtl so here's a longstanding one I've had to work around.
When a user's torrc has a relative data directory (which is the case for everyone using TBB) the paths based on that become relative too. Most importantly this includes the path of the authentication cookie, preventing TorCtl from connecting to any TBB instance using cookie auth.
This is a bug with tor [1] but with some work the paths can be expanded on most platforms. With arm and stem I'm transparently correct the paths, for code to do this see 'ProtocolInfoResponse' in the connection module [2].
Cheers! -Damian
[1] https://trac.torproject.org/projects/tor/ticket/1101 [2] https://gitweb.torproject.org/stem.git/blob/HEAD:/stem/connection.py