Re: [Xen-devel] [PATCH V13 5/5] xl: add pvusb commands

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Thu, 2016-01-21 at 12:12 +0000, Wei Liu wrote:
> On Tue, Jan 19, 2016 at 08:10:07PM -0700, Jim Fehlig wrote:
> > On 01/19/2016 11:11 AM, Ian Jackson wrote:
> > > Chunyan Liu writes ("[PATCH V13 5/5] xl: add pvusb commands"):
> > > > Add pvusb commands: usbctrl-attach, usbctrl-detach, usb-list,
> > > > usbdev-attach and usbdev-detach.
> > > Thanks for swapping this with the other patch.ÂÂIt is better now.
> > > 
> > > > +=item B<usbctrl-attach> I<domain-id> I<usbctrl-device>
> > > However, I think you need to explictly state that the user may (and
> > > indeed, must) pass multiple settings as separate arguments.ÂÂAFAICT
> > > the parser here doesn't do the ,-splitting.
> > 
> > I just noticed this is the case with network devices as well. E.g.
> > 
> > #xl network-attach hvm-domU mac=00:16:3e:xx:yy:zz,bridge=br0
> > libxl: error: libxl_device.c:1095:device_hotplug_child_death_cb:
> > script: Could
> > not find bridge device xenbr0
> > 
> > main_networkattach() in tools/libxl/xl_cmdimpl.c doesn't split on the
> > ',', so
> > everything after mac=00:16:3e:xx:yy:zz is ignored. I'd need advice on
> > how to fix
> > this though. Based on xl-network-configuration doc and Xen tool's long
> > history
> > of network-attach supporting that syntax, I'd say main_networkattach()
> > should be
> > changed to split on ','. I could also change the docs. Do tools
> > maintainers have
> > a preference, or alternative option?
> > 
> 
> It is splitting on " " at the moment which is not very desirable.
> 
> I think this is a bug. I've added it to my list and will look into
> fixing it.

If you are feeling particularly highly motivated then xl_cmdimpl.c contains
quite a lot of adhoc parsing of various comma a space separated lists
(often dupped for a given instance into cmdline vs cfg file, which leads to
unintentional behavioural differences like above) which could usefully be
consolidated into a series of helpers.

Ian.


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