top not restoring terminal echo/icanon correctly

[Jeremy Chadwick]

On Tue, Apr 17, 2012 at 11:22:42AM -0700, Jeremy Chadwick wrote:
> (Please keep me CC'd as I'm not subscribed to the list)
> 
> I'd like to request that folks running RELENG_8 (and RELENG_9, though I
> do not use it) please check the behaviour of their terminal after each
> of following commands are run (check terminal after each command):
> 
> top -a  (press "q" after 1 screen refresh)
> top -b
> 
> If you find that your input characters in your shell aren't being echo'd
> back after one of the above commands, blindly type "stty icanon echo"
> and hit <Enter> and things should be back to normal.
> 
> What I'm looking for is confirmation from others of the problem.
> 
> Also very important: please provide uname -a output, specifically world
> rebuild date.  It greatly matters, because a commit was recently done
> where now -b functions fine (was previously busted in this way), but now
> -a behaves like -b did.  So src/world date matters.
> 
> All of this is documented in PR 161739.  I urge anyone experiencing this
> problem to read that PR in full, as I spent many hours today writing a
> debug routine to confirm that top is sometimes not calling tcsetattr()
> with the original terminal parameters when it exits, and what the
> condition seems to be.
> 
> http://www.freebsd.org/cgi/query-pr.cgi?pr=bin/161739
> 
> Finally, if anyone want to tackle the problem (work out the logic bug
> that is in there which causes it), please be my guest.  I have other
> things going on right now (doctors appointments) so I don't have as much
> time as I'd like.
> 
> Thanks everyone.

Thanks to all those who have responded, including kib at .

The problem is very odd and appears specific to the bash shell, but
only "somewhat".  Below is a part of what I sent kib@ on the matter.
A chart showing what I've found:

Location      Username   TERM     Shell                 bug?
=============================================================
VGA console   root       cons25   /bin/csh              no
VGA console   jdc        cons25   /usr/local/bin/bash   no
SSH (PuTTY)   root       xterm    /bin/csh              no
SSH (PuTTY)   jdc        xterm    /bin/csh              no
SSH (PuTTY)   jdc        xterm    /usr/local/bin/bash   yes
=============================================================

In the last case (and only that case): if I move my dotfiles (.bashrc
and .bash_profile) aside and log in (SSH), top behaves normally.
Naturally this made me think "something is wonky with my dotfiles!"...

But the problem *doesn't* happen if my dotfiles are intact and I
log in via VGA console (cons25) as myself with a bash shell.  So it's
almost like there's some bizarre combination of things that causes this
problem.

I'll continue to try and narrow it down.

-- 
| Jeremy Chadwick                                 jdc at parodius.com |
| Parodius Networking                     http://www.parodius.com/ |
| UNIX Systems Administrator                 Mountain View, CA, US |
| Making life hard for others since 1977.             PGP 4BD6C0CB |