Re: [gpsd-dev] Last known 3.12 blocker solved

[Eric S. Raymond]

Hal Murray <address@hidden>:
> 
> address@hidden said:
> > The test mode does *not* do anything with those segments - nothing gets
> > written to them unless gpsd sees a PPS event and there's no way for that to
> > happen when it's being driven by ptys.  gpsd allocates them up front only
> > because of the privilege-dropping issue. 
> 
> I don't understand that.
> 
> Why does gpsd setup those segments if it's not going to use them?

Because without setting up the 660 segments befor it drops privileges it
wuill never get them.  The problem is that in order to present a minimal
attack surface we have to drop privileges well before it's known whether
any device with PPS will connect.
 
> How does gpsd know that it shouldn't use SHM for a normal serial stream when 
> running in test mode and/or why would it use SHM if it sees a PPS in test 
> mode?

gpsd has no reason to ever use SHM in test mode.  But see above.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>