[tbox-l] Tcl over SSH problem (revisited)

[Markus A. <al...@de...>]

Hi all,

lately a user here ran into a problem that seems to be same as the one
described in [1]. He logged into a remote machine using OpenSSH and ran
a Tcl script. This script was executed, but afterwards the SSH
connection just "hung", i.e. he did not get a shell prompt.

I could easily reproduce this with either the well-known


#!/usr/bin/tclsh

puts "Hello world"


or by just typing "tclsh" and then "exit" at tclsh's prompt. In addition
to that, two persons at other IBM sites that I've contacted did also see
this behaviour. So it seems to me as if the bug described in [1] still
exists in the AIX Toolbox for Linux Tcl RPM.

Apparently it is related to the way Tcl handles input/output to
stdin/stdout, as "helloworldscript | cat -" surprisingly worked! And it
also only happens with an OpenSSH connection; after logging in via
telnet or rlogin there was no problem with Tcl.

This is on AIX 5.1 with Tcl 8.3.3 and various version of OpenSSH
(self-compiled 3.9p1 as well as the 3.8.1p1 LPP provided by IBM for AIX
5.1).

I've done some more tests with other - older and newer - Tcl versions
that we and other IBM sites have installed in distributed filesystem and
found the following:

 - versions 7.3, 7.4 and 8.0 worked
 - version 8.2 did *not* work
 - versions 8.3.1 and 8.3.3 (both from AIX Toolbox RPMs) did *not* work
 - version 8.3.4 did *not* work
 - version 8.4.4 worked

Looks like this obvious bug has been introduced in the Tcl code after
8.0 and fixed in the latest 8.4 release. Googling for "tcl 8 ssh" I've
found a bug report [2] from 2001 that refers to AIX 4.3.3, but seems to
exactly describe the problem.

So finally my questions are:

 1. Can anybody reproduce this behaviour?
 2. If yes, are there plans to release an updated Tcl RPM? Either the
same version with a patch or a new version (i.e. 8.4). (Yes, I know
about the legal battle with newer versions ... :-/ )

Any comments are much appreciated!

TIA & regards,
Markus


[1]
http://sourceforge.net/tracker/index.php?func=detail&aid=1150486&group_id=128955&atid=712808
[2] http://aspn.activestate.com/ASPN/Mail/Message/tcl-bugs/822555

-- 
Markus Alt
IBM Lab Boeblingen, Germany
al...@de...