From: tom@bim.itc.univie.ac.at (Tom Kovar) Subject: getty/login/sgtty & serial port Date: 1 Apr 1993 09:52:23 GMT
Hi folks,
I fear it is an old beer I want to ask, but I am rather Linux newbie...
(fortunatelly no UNIX newbie :-)
I've got big problems with getty, to be more exact with trying to get
into the system over a modem on a serial line; but in the meantime I am
sure the problem lies somewhere between the serial port and getty.
There is no problem to get outside over the modem. But if I want to
make an incoming call, the following happens:
a) if I start getty (or uugetty) from a running system (i.e. not from
inittab), it brings the login prompt quite OK, accepts the login name,
and starts the propper login process (login with the right parameter,
userid). But interestingly enough, the echo is not turned off, the
process does not really read the password, and after a while (60
seconds is set in getty, I think) it timeouts.
A propos, the same strange behaviour can be observed, even if I start
getty to a free virtual console.
b) if I start getty from inittab, it is even more strange - the caller
gets properly the login prompt to his screen (the autobauding works
right), he types in his userid, and the getty exec's again the propper
login process. But in this case, neither the Password prompt is
sent to the screen, nor does any input reach the login process again,
until it dies...
Getty exhibits also another very strange behaviour - it blocks completely
the serial device, so that all processes that try to open it will either
wait forever, or (if O_NDELAY) open returns an error. But in the sources
of getty (using 2.05 getty_ps, and tried to compile it with all imaginable
permutations of compiler options) I haven't found any speciall ioctl- or
fcntl settings that could cause that... Btw., if getty dies/is killed,
the device remains blocked.
If I start any programme of mine, that opens the serial port and reads it,
nothing of this kind appears. I fear it might be caused by the
sgtty call??? Anyhow, it's settings seem to be ignored...
Hm, a rather important remark. I am running 0.99pl6 (yes, sorry, I haven't
upgraded yet) and gcc2.3.3. I installed Linux from the SLS distribution,
and havent patched the system in any way (yet).
I have seen some similar questions in this group already, but never
seen a reply. Can anyone help me? Many thanks,
Tom
--___ / ___ / ____/ Tomas Kovar / / / / / Alcatel Austria Forschungszentrum G.m.b.H. ___ / ___ / __/ A-1210 Wien, Ruthnergasse 1-7 / / / / / Tel: +431-391621-283 Fax: +431-391452 __/ __/ __/ __/ __/ E-Mail: Tom.Kovar@rcvie.co.at