status of the hang-on-exit-bug

mouring at mouring at
Wed Oct 24 01:48:28 EST 2001

> > unlike sshd both telnetd and rlogind exit on SIGCHLD. however, this
> > is because they don't care about lost data. but ssh needs to care.
> > rlogin does not. this is why ssh hangs and rlogin does not.
> what's the rationale for not using the rlogin behavior for interactive
> sessions and rsh behavior for non-interactive sessions? (tty/notty)

This has been talked about recently amoung the developers.  And we are
still confused why OpenBSD does not result this this bug, but a large
amount of the UNIXes do show it.  It would be nice if we could learn the
'why' and fix the underlying issue we could could.  However, no one seems
to be able to provide such an answer.

There is a v2 patch (I've not checked the latest CVS tree due to personal
issues) that hides this problem for tty sessions connections proposed by
Markus.  It does it by disgarding any left over data in the datastream on
an interactive session.

- Ben

More information about the openssh-unix-dev mailing list