ssh hanging--a workaround

[Karl M]

Hi Corinna...

I don't have a solution to the ssh hanging problem when it is forked off as 
in

ssh -f localhost sleep 10

but have a workaround. The patch file is attached.

I looked at both ssh and sshd when they hang (both in their respective 
select calls--which makes sense because they are both waiting for something 
to do). The problem is in ssh. When ssh is forked after authentication, the 
select call fails to return after the fifth time that it is invoked. This 
problem only seems to occur when ssh has invoked daemon before starting the 
interactive session, but the problem shows up four select calls later. As 
part of my debugging, I forced select to return by setting a timeout. The 
timeout does force it to return--and in fact, there is IO waiting to be 
processed. So a one second timeout in the select call is my workaround for 
now.

The read and write bit masks before and after the select call always look 
fine. It is not an ssh bug as far as I can tell.

ssh localhost sleep 10

ssh -f localhost sleep 10

are the two test cases I used for debugging--to compare the behavior.

Also, in the past, I needed pipes and you did not. Now we all have pipes. 
But why do you think that in the past, I needed pipes and you did not?

Thanks,

...Karl
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