Re: [uml-user] con=port: "rcv_fd didn't receive anything"

[Jeff D. <jd...@ka...>]

b_...@ya... said:
> (what does port-helper do, btw?)

It fakes out telnetd, basically.  telnetd expects to exec the login program,
but in this case, the login program is the UML port backend, which is already
running.  So, port_helper is execed by telnetd and passes its tty over to
UML, at which point it just sits there.

> I'll try it on another machine tomorrow - how could one go  about
> debugging this? :-)

Make sure you're running the latest of everything.

I'd like to see a strace of port_helper.

If you want to rebuild UML, I would change this, in arch/um/drivers/port.c:

	char *argv[] = { "/usr/sbin/in.telnetd", "-L", 
			 "/usr/lib/uml/port-helper", NULL };

to:

	char *argv[] = { "/usr/bin/strace", "-f", "/tmp/strace.out",
			 "/usr/sbin/in.telnetd", "-L", 
			 "/usr/lib/uml/port-helper", NULL };

If you don't, then move /usr/lib/uml/port-helper to 
/usr/lib/uml/port-helper.real and make /usr/lib/uml/port-helper look like:

#!/bin/bash

strace -f /tmp/strace.out /usr/lib/uml/port-helper.real $@

(Both off the top of my head, but they should work).

Send in the strace log, and we'll see what happened.

				Jeff