[libvirt] [PATCH 4/4] remote: Detect 'nc' version incompatibilities

[Daniel P. Berrange]

On Mon, Feb 15, 2010 at 09:39:31AM -0500, Cole Robinson wrote:
> On 02/15/2010 06:11 AM, Daniel P. Berrange wrote:
> > On Fri, Feb 12, 2010 at 10:32:17AM -0500, Cole Robinson wrote:
> >> This ugly thing is a shell script to detect availability of
> >> the -q option for 'nc': debian and suse based distros need this
> >> flag to ensure the remote nc will exit on EOF, so it will go away
> >> when we close the tunnel. If it doesn't go away, a useless 'nc'
> >> process is left sitting on the remote host.
> >>
> >> Fedora's 'nc' doesn't have this option, so we can't blindly pass -q.
> >> More info here:
> > 
> > I don't really like this approach. Shouldn't it be sufficient to
> > just explicit SIGKILL the ssh client, rather than relying on the
> > exit-on-EOF behaviour of nc.
> > 
> 
> kill() helps prevent virt-manager from hanging, but it doesn't address the
> dangling 'nc' process on the remote host that requires -q. Every connection
> will leave an 'nc' process hanging.

It does when I try it. Killing the SSH client connection results in SIGHUP
for the process running on the  remote host & nc exits on SIGHUP.


Daniel
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