Re: [Xen-devel] [PATCH v4 3/4] libxl: call hotplug scripts from libxl for vbd

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Ian Campbell escribiÃ:
> On Mon, 2012-05-14 at 13:38 +0100, Roger Pau Monne wrote:
> > > > +# Hack to prevent the execution of hotplug scripts from udev if the domain
> > > > +# has been launched from libxl
> > > > +if [ -n "${UDEV_CALL}" ]&&   \
> > > > +   `xenstore-read "libxl/disable_udev">/dev/null 2>&1`; then
> > > This reads something from xenstore and executes it as a shell command!
> > > (Also it will go wrong if the value read is empty eg becaue the key
> > > doesn't exist.)
> > Are you sure about this? This command never returns anything, because it
> > is redirected to /dev/null, so we only evaluate if it is able to read
> > libxl/disable_udev. If libxl/disable_udev exists this test is passed.
> You don't need the backticks for that though. With the backticks it will
> execute whatever happens to be in the key -- I guess it's something
> quite benign right now or you'd have seen errors.
Yes, it's not the first time that I've made that mistake. Since it never 
returns anything I guess that's why I never saw any errors.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel