libvirt users - Aug 2015 - On which /dev/pts/x is channel source mapped ?

Hi,

By adding following lines in a Guest .xml  conf file , I'm able to send /
receive datas between host and this guest.

<channel type='pty'>
      <target type='virtio'
name='arbitrary.virtio.serial.port.name'/>
      <address type='virtio-serial' controller='0'
bus='0' port='1'/>
    </channel>

My question  is the following :

How may I find to which  /dev/pts/x  is mapped the source path  ( from the host
point of view) ?
I was able to find it by having a look in the virt manager GUI , but I want to
do it programmatically.

I've tried to force it by specifying a source path in the .xml file .... No
way


Thx for help.

Regards,

J.P. Ribeauville


P: +33.(0).1.47.17.27.87


Puteaux 3 Etage 5  Bureau 4

jpribeauville@axway.com<mailto:jpribeauville@axway.com>
http://www.axway.com<http://www.axway.com/>



P Pensez à l'environnement avant d'imprimer.

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Dear Jean-Pierre,

Here, at the ReactOS Foundation, we've hit the same issue with our
automated regression testing using KVM (and thus, libvirt).

The solution we use is that we first start the VM and then, we ask
libvirt to dump the VM XML and we parse it to get the pts.

I'm not sure whether that's the most efficient method, but at least,
that's a method that works.

You can have a look at our code which is GPLv2. It is available here:
https://svn.reactos.org/svn/project-tools/trunk/sysreg2/
More specifically, the part where we ask again for the config happens
in kvm.cpp, KVM class, in KVM::GetConsole() function.

I hope it helps. If you need more information, don't hesitate to ask.

Cheers,

On 08/25/2015 05:17 PM, Jean-Pierre Ribeauville wrote:
> Hi,
> 
> By adding following lines in a Guest .xml  conf file , I'm able to
> send / receive datas between host and this guest.
> 
> <channel type='pty'> <target type='virtio'
> name='arbitrary.virtio.serial.port.name'/> <address
> type='virtio-serial' controller='0' bus='0'
port='1'/> </channel>
> 
> My question  is the following :
> 
> How may I find to which  /dev/pts/x  is mapped the source path  (
> from the host point of view) ? I was able to find it by having a
> look in the virt manager GUI , but I want to do it
> programmatically.
> 
> I've tried to force it by specifying a source path in the .xml file
> .... No way
> 
> 
> Thx for help.
> 
> Regards,
> 
> J.P. Ribeauville
> 
> 
> P: +33.(0).1.47.17.27.87
> 
> 
> Puteaux 3 Etage 5  Bureau 4
> 
> jpribeauville@axway.com<mailto:jpribeauville@axway.com> 
> http://www.axway.com<http://www.axway.com/>
> 
> 
> 
> P Pensez à l'environnement avant d'imprimer.
> 
> 
> 
> 
> 
> 
> _______________________________________________ libvirt-users
> mailing list libvirt-users@redhat.com 
> https://www.redhat.com/mailman/listinfo/libvirt-users
> 

- -- 
Pierre Schweitzer <pierre@reactos.org>
System & Network Administrator
Senior Kernel Developer
ReactOS Deutschland e.V.
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On Tue, Aug 25, 2015 at 03:17:51PM +0000, Jean-Pierre Ribeauville
wrote:
> Hi,
> 
> By adding following lines in a Guest .xml  conf file , I'm able to send
/ receive datas between host and this guest.
> 
> <channel type='pty'>
>       <target type='virtio'
name='arbitrary.virtio.serial.port.name'/>
>       <address type='virtio-serial' controller='0'
bus='0' port='1'/>
>     </channel>
> 
> My question  is the following :
> 
> How may I find to which  /dev/pts/x  is mapped the source path  ( from the
host point of view) ?
You have to queryy the XML from libvirt after the guest has started,
at which point libvirt will have filled in the dynamically alllocated
pty path.

Honestly, you're probably better off not using type='pty', and
instead use type='unix', which lets you specify an explicit
UNIX domain socket path upfront, avoiding the whole problem.


Regards,
Daniel
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