hang on exit bug under Linux

[Nicolas Williams]

On Fri, Jan 04, 2002 at 09:32:29AM -0500, Nicolas Williams wrote:
> On Fri, Jan 04, 2002 at 09:15:26AM +0100, Peter Stuge wrote:
> > (The deal is that I want to make a certain PID a child of a different PID
> > than it is right now.)
> 
> You can't do that.
> 
> You can put ssh into the background by forking off a child and exiting,
> but then the shell cannot bring that child back to the foreground.
> Which makes the background option not so useful. Perhaps you can just
> have ssh send itself a SIGTSTP, but then you have to rely on the user to
> ask the shell to actually background the process.

In fact, I just tested that approach and it works, mostly, though the
shell I tested it with becomes confused about the status of the jobs
after it gets SIGCONT. But it works. If ssh is going to do any stdio
when it gets SIGCONT, then it will likely get SIGTTIN or SIGTTOU
though.

Personally, I don't think the self-background option is very practical.
I would be happy with an option to close the channels and exit when ssh
receives the session exit message.

Here's a script to emulate what I'm saying:

#!/bin/ksh

date
foo=$$
print $foo
trap 'print continue' CONT

( sleep 5 ; kill -CONT $foo ) > /dev/null 2>&1 &

print "Stopping $foo"
kill -TSTP $foo
sleep 10
print "hey there"
date

exit 0


> > //Peter
> > 
> 

Cheers,

Nico
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