[Qemu-devel] Using QEMU guest agent to run programs from guest path

[Qemu-devel] Using QEMU guest agent to run programs from guest path

[Erlon Cruz]

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Hi,


I needed to run an external program in a guest machine. Once this must be
triggered by the host, I first thought in qemu-ga.
Is that possible? In QEMU help page and in the code I couldn't find such
capability.
So Im thinking In to implement a new GA QMP command that can run generic
programs in the guest. It would be receive/return something like this:

{"execute":"execvp",
"arguments":{"command":"/bin/ls","cmdargs":"-la","timeout":20}}
{"return": {"status": "0", "stdout": "aGVsbG8gd29ybGQhCg==", "stderr": ""}}

Any thoughts/ideas about this?

Kind Regards,
Erlon

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Re: [Qemu-devel] Using QEMU guest agent to run programs from guest path

[mdroth]

On Mon, Dec 31, 2012 at 06:14:59PM -0200, Erlon Cruz wrote:
> Hi,
> 
> 
> I needed to run an external program in a guest machine. Once this must be
> triggered by the host, I first thought in qemu-ga.
> Is that possible? In QEMU help page and in the code I couldn't find such
> capability.
> So Im thinking In to implement a new GA QMP command that can run generic
> programs in the guest. It would be receive/return something like this:
> 
> {"execute":"execvp",
> "arguments":{"command":"/bin/ls","cmdargs":"-la","timeout":20}}
> {"return": {"status": "0", "stdout": "aGVsbG8gd29ybGQhCg==", "stderr": ""}}
> 
> Any thoughts/ideas about this?

I sent an RFC for this a while back:

http://lists.gnu.org/archive/html/qemu-devel/2011-12/msg00722.html

At the time the interface seemed a bit tedious, but AFAIK it's the only
kind of approach that'll work for longer-running commands with lots of
output, so I might just clean it up and re-spin the series.

> 
> Kind Regards,
> Erlon

Re: [Qemu-devel] Using QEMU guest agent to run programs from guest path

[Erlon Cruz]

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On Wed, Jan 2, 2013 at 9:04 PM, mdroth <mdroth@linux.vnet.ibm.com> wrote:

> On Mon, Dec 31, 2012 at 06:14:59PM -0200, Erlon Cruz wrote:
> > Hi,
> >
> >
> > I needed to run an external program in a guest machine. Once this must be
> > triggered by the host, I first thought in qemu-ga.
> > Is that possible? In QEMU help page and in the code I couldn't find such
> > capability.
> > So Im thinking In to implement a new GA QMP command that can run generic
> > programs in the guest. It would be receive/return something like this:
> >
> > {"execute":"execvp",
> > "arguments":{"command":"/bin/ls","cmdargs":"-la","timeout":20}}
> > {"return": {"status": "0", "stdout": "aGVsbG8gd29ybGQhCg==", "stderr":
> ""}}
> >
> > Any thoughts/ideas about this?
>
> I sent an RFC for this a while back:
>
> http://lists.gnu.org/archive/html/qemu-devel/2011-12/msg00722.html
>
> At the time the interface seemed a bit tedious, but AFAIK it's the only
> kind of approach that'll work for longer-running commands with lots of
> output, so I might just clean it up and re-spin the series.
>
>
Why you say tedious? The interface seems to have a very wide usage for
several scenarios and fits perfectly for what we are trying to do. Why it
didn't go upstream? I think it would be nice to roll that up again.

Erlon

>
> > Kind Regards,
> > Erlon
>

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Re: [Qemu-devel] Using QEMU guest agent to run programs from guest path]

[mdroth]

On Thu, Jan 03, 2013 at 11:06:02AM -0200, Erlon Cruz wrote:
> On Wed, Jan 2, 2013 at 9:04 PM, mdroth <mdroth@linux.vnet.ibm.com> wrote:
> 
> > On Mon, Dec 31, 2012 at 06:14:59PM -0200, Erlon Cruz wrote:
> > > Hi,
> > >
> > >
> > > I needed to run an external program in a guest machine. Once this must be
> > > triggered by the host, I first thought in qemu-ga.
> > > Is that possible? In QEMU help page and in the code I couldn't find such
> > > capability.
> > > So Im thinking In to implement a new GA QMP command that can run generic
> > > programs in the guest. It would be receive/return something like this:
> > >
> > > {"execute":"execvp",
> > > "arguments":{"command":"/bin/ls","cmdargs":"-la","timeout":20}}
> > > {"return": {"status": "0", "stdout": "aGVsbG8gd29ybGQhCg==", "stderr":
> > ""}}
> > >
> > > Any thoughts/ideas about this?
> >
> > I sent an RFC for this a while back:
> >
> > http://lists.gnu.org/archive/html/qemu-devel/2011-12/msg00722.html
> >
> > At the time the interface seemed a bit tedious, but AFAIK it's the only
> > kind of approach that'll work for longer-running commands with lots of
> > output, so I might just clean it up and re-spin the series.
> >
> >
> Why you say tedious? The interface seems to have a very wide usage for

The parameter passing for guest commands was kludgy (list of json
objects rather than a list of parameter strings), but I think we can handle
that now with the "gen: no" option to the code parser indicating we'll
handle it manually.

I'm not sure about the guest-file-open-pipe stuff either. It seems
clumsy, but I can't think of a better approach.

I'll look at it and shoot to get in by 1.4, but feature freeze is only a
couple weeks away so it may have to wait till 1.5.

> several scenarios and fits perfectly for what we are trying to do. Why it
> didn't go upstream? I think it would be nice to roll that up again.
> 
> Erlon
> 
> >
> > > Kind Regards,
> > > Erlon
> >

Re: [Qemu-devel] Using QEMU guest agent to run programs from guest path]

[Erlon Cruz]

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> The parameter passing for guest commands was kludgy (list of json
> objects rather than a list of parameter strings), but I think we can handle
> that now with the "gen: no" option to the code parser indicating we'll
> handle it manually.
>
> I'm not sure about the guest-file-open-pipe stuff either. It seems
> clumsy, but I can't think of a better approach.
>
>
Hmmm, I see, not really sure if I can help too. I know almost nothing about
the parser. :/

I'll look at it and shoot to get in by 1.4, but feature freeze is only a
> couple weeks away so it may have to wait till 1.5.
>
>
Nice, I guess that will take around 3 months right?


Erlon

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