[E3-hacking] PBL & running arbitrary code

David Given e3-hacking@earth.li
Sat, 12 Mar 2005 22:30:35 +0000

On Sat, 2005-03-12 at 19:40 +0000, Ralph Corderoy wrote:
> Possibly.  Both Matt and I independently assumed a key held down on the
> telephone keypad, that's probably our Acorn backgrounds, but nothing in
> the code suggests that AFAIK.

I can't think of anything else that it could be --- unless the trigger's
something in the firmware, and that my unit has been locked down, and
your units haven't.

(My unit *does* seem to be a little different --- Matt, have you taken
the lid off yours yet? Does it have an SMC adaptor soldered onto the top
of the motherboard? What PBL version and build is it? [Start it up,
press SETUP, 1.])

> > This seems to send a single 1B, and bail with a EOF error when it
> > tries to read the response.
> It shouldn't do that.  Is that what actually happens, in which case the
> stdout and stderr would be handy, or what you think from a quick look?

That was what strace gave.

I actually sorted this out; because my program, pblq, was not calling
tcgetattr but was resetting the termios structure to zeros, it was doing
something strange to the serial port settings that exp couldn't cope
with. I fixed pblq and exp now works fine --- the E2 still won't talk to
it, though.


Incidentally, useful factoid. The boot process goes like this:

     1. Splash screen (pretty picture of the emailer).
     2. Title screen (with 'Personal Communication Centre' across the
     3. Main menu.

If on the transition between 1 and 2, you press STOP+HANDSFREE, the
machine will reset itself back into a virgin state.

Do we know yet what puts up the splash screen? PBL or the main software?
What do you see on a successfully suspended boot?

+- David Given --McQ-+ 
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| (dg@tao-group.com) | hand and a sword in the other." --- Sir Boyle Roche
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