[9fans] ctrl-d and rio

[9fans] ctrl-d and rio

[Steve Simon]

When I run a user level fileservers, eg my own cifs
and then close the window with ctrl-d the window doesn't close,
I have to use rio to delete the window.

This doesn't happen with the likes of ftpfs.

At first I though I was holding /dev/cons open so I close
fds 0, 1, and 2 and lsof shows me I only have the network
connection (and /dev/bintime) open.

why don't my programs cleanup nicely?

-Steve

Re: [9fans] ctrl-d and rio

[andrey mirtchovski]

i've seen the same problem when starting the plumber in a new
namespace.  ctrl+d doesn't close the window, but if i hit 'del' (and
kill the plumber) it goes away.  it's very easy to reproduce.

never been bothered by it enough to look at the cause and assumed it's
just open file descriptors.  still, i am interested in hearing
explanations/solutions.

andrey

Re: [9fans] ctrl-d and rio

[rog]

> never been bothered by it enough to look at the cause and assumed it's
> just open file descriptors.  still, i am interested in hearing
> explanations/solutions.

this has nagged at me too in the past, so i just had a look into it.

there are two reasons (in in the plumber case, at any rate)
why the shell window doesn't disappear correctly.
the first is a bug in /sys/src/cmd/plumb/fsys.c:/^startfsys

	procrfork(fsysproc, nil, Stack, RFFDG);

should be:

	procrfork(fsysproc, nil, Stack, RFFDG|RFNAMEG);

otherwise the process serving the plumbing namespace is also holding
that namespace open.

but even with that fixed, the plumber automatically creates an entry
in /srv.  this holds the 9p pipe to the plumber open even when the
shell holding the plumber's namespace exits.

removing the /srv file allows the window to disappear correctly (a rio
window only exits when the window's namespace is no longer
referenced).

so, assuming the first fix,

	plumber
	rm `{cat /env/plumbsrv}

would be sufficient (although an option suppressing the /srv posting
would likely be preferable).

Re: [9fans] ctrl-d and rio

[rog]

this reminds me.

if i wish to run a command in the background from a window
without stopping the window from closing automatically when
the shell terminates, is there a simpler way than:

@ {
	rfork n
	unmount /mnt/wsys /dev
	unmount /mnt/wsys
	exec mycommand < /dev/null > /dev/null >[2] /dev/null &
}

?