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Re: [Qemu-devel] feature idea: allow user to run custom scripts
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] feature idea: allow user to run custom scripts |
Date: |
Wed, 30 Sep 2015 09:14:41 +0100 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
* Markus Armbruster (address@hidden) wrote:
> "Dr. David Alan Gilbert" <address@hidden> writes:
>
> > * Peter Maydell (address@hidden) wrote:
> >> On 29 September 2015 at 14:11, Dr. David Alan Gilbert
> >> <address@hidden> wrote:
> >> > * Peter Maydell (address@hidden) wrote:
> >> >> On 28 September 2015 at 20:43, Programmingkid
> >> >> <address@hidden> wrote:
> >> >> >
> >> >> > On Sep 28, 2015, at 3:29 AM, Markus Armbruster wrote:
> >> >> >> You didn't mention you're talking about a *GUI* feature.
> >> >> >
> >> >> > I'm thinking it would be easier to send in the patch rather
> >> >> > than talk about
> >> >> > what this feature could be.
> >> >>
> >> >> I think Markus and I are trying to save you that effort by
> >> >> pointing out that this is a VM management layer feature,
> >> >> not a core QEMU feature.
> >> >
> >> > OK, so I'm going to agree with Programmingkid here.
> >> > I think this would be a useful feature to have in QEMU; I've
> >> > got gratuitous hacks in some of my test scripts that work
> >> > around it not being there.
> >> >
> >> > I think there are two possible things, both of which seem fairly
> >> > easy:
> >> > 1) Add a -chardev from file that works in this case
> >> > (I don't think the current chardev file works does it?)
>
> In general, character devices provide a bidirectional pipe, but -chardev
> file is write-only. I think you want -chardev pipe. I don't use it
> myself, because as socat user, I don't have to learn lesser tools :)
>
> Here's how I use it. Set up a local socket (any convenient
> bidirectional pipe would do, actually).
>
> Example: QMP
>
> # Configuration file for -readconfig
> [chardev "qmp"]
> backend = "socket"
> path = "sock-qmp"
> server = "on"
> wait = "off"
>
> [mon "qmp"]
> mode = "control"
> chardev = "qmp"
>
> Example: HMP
>
> [chardev "hmp"]
> backend = "socket"
> path = "sock-hmp"
> server = "on"
> wait = "off"
>
> [mon "hmp"]
> mode = "readline"
> chardev = "hmp"
>
> Then do stuff with it.
>
> Example: interactive QMP
>
> $ socat UNIX:sock-qmp READLINE,history=$HOME/.qmp_history,prompt='QMP> '
>
> Example: interactive HMP
>
> $ socat UNIX:sock-hmp READLINE,history=$HOME/.hmp_history
>
> Arguably superior to our built-in not-quite readline monitor.
>
> Example: send QMP input from a file, capture its output in a file
>
> $ socat UNIX:sock-qmp STDIO <input >output
Yes, this example is exactly why I want something less painful.
A -chardev file that allowed read/write would be ideal, to be able to read
a series of commands at startup.
> >> > 2) A 'source' like command.
>
> QMP? The command would have to take a filename as argument, and return
> a list of replies. Probably stop on first failed command. Pretty
> useless for remote clients, because if you have to upload the file, you
> can just as well send it down the QMP pipe. Actually, that pretty much
> applies to local clients, too. Except perhaps for interactive use. I
> feel a QMP client geared for such use would be the appropriate home for
> this feature. We have some in scripts/qmp/.
>
> I don't have an opinion on HMP right now.
If QMP doesn't have a user for it fine; I'm just saying it would be useful
from my point of view in HMP.
> >> Yeah, these are both plausible. Neither of them are GUI features,
> >> though...
> >
> > Well, I don't use the GTK gui; I can see that those who do
> > might want features in it.
>
> GUI users want GUI features, of course.
>
> In my opinion, QEMU should leave them to separate GUI shells, because
> doing everything in QEMU distracts from our core mission and we don't
> have GUI expertise[*]. One more point: building in the GUI is
> problematic when you don't trust the guest, because then you really want
> to run QEMU with least privileges.
Given that we have a built in GUI then I can see people wanting to expand
it.
Dave
>
>
> [*] Short version of the argument, for the long one, see
> Message-ID: <address@hidden>
> http://lists.gnu.org/archive/html/qemu-devel/2015-08/msg03916.html
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Dr. David Alan Gilbert, 2015/10/07
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Programmingkid, 2015/10/07
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Peter Maydell, 2015/10/07
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Dr. David Alan Gilbert, 2015/10/07
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Markus Armbruster, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts,
Dr. David Alan Gilbert <=
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Peter Maydell, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Programmingkid, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Paolo Bonzini, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Kevin Wolf, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Daniel P. Berrange, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Programmingkid, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Markus Armbruster, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Markus Armbruster, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Dr. David Alan Gilbert, 2015/10/08
- Re: [Qemu-devel] feature idea: allow user to run custom scripts, Daniel P. Berrange, 2015/10/08