NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/comp/sys/pyramid/233

Internet Message Format | 1992-12-21 | 1.8 KB

Path: sparky!uunet!uswnvg!nv77.uswnvg.com!rfadler
From: [e-mail] (Rick Fadler [phone])
Newsgroups: comp.sys.pyramid
Subject: psuedo-ttys on OSx 5.1a
Keywords: pty ioctl
Message-ID: <[e-mail]>
Date: 18 Dec 92 16:28:27 GMT
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Distribution: usa
Organization: U S WEST NewVector Group, Inc.
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I have recently inherited some code that, unfortunately was not completed
before the original author left. As a result I have come across some
interesting system calls that appear to be undocumented.

The calls are, open_controlling_pty and open_slave_pty. They are both found
in the library /usr/.ucblib/libpyr.a.

What is unusual is that when I run the application with a regular user id
they work fine, but when executed as root the function
"open_controlling_pty" causes a coredump.  I have traced the dump using dbx
and it points to open_controlling_pty.

This doesn't make sense to me and so far I have found no manual pages or
other documentation on this function. Unfortunately the programmer who wrote
the code is no longer here to explain it all to me.

My second question is once I get the master pty open (which works when run
as a regular user) I try to send data to the master pty. Unfortunately local
echo of NL "ECHONL" is enabled on the pty which causes any new line that
is sent to the pty to be echoed back to the application.  This is causing a
whole lot of problems. I have tried to use ioctl to turn off ECHONL but even
though the ioctl succeeds, when I check the setting ECHONL is still turned
on.  One collegue suggested that perhaps only a subset of the requests are
valid when you are dealing with a master pty. Does anyone know of any
documentation concerning ioctl and ptys?

Any advice, comments, jokes, etc. would be appriciated.

Rick Fadler