twistd logfile and UID/GID privileges

[tomsheffler]

When twistd starts as root, and is asked to drop privileges to UID/GID, and it is creating and rotating a logfile, the following will occur:

- the logfile wll be created as root - the logfile will be rotated as UID/GID

The current implementation places some strange restrictions on setting up LOGDIR, and if these restrictions aren't followed some undocumented things happen.

- If LOGDIR is writable by UID/GID and LOGFILE is writable by UID/GID then a new logfile will be opened and old files will be rotated - else, the initial logfile will be appended to indefnitely

Read here for more back information:  http://www.tsheffler.com/blog/?p=526