From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37998) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g8Lno-0000G2-V8 for qemu-devel@nongnu.org; Fri, 05 Oct 2018 04:49:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g8Ld4-00071N-5G for qemu-devel@nongnu.org; Fri, 05 Oct 2018 04:38:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22388) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1g8Ld3-0006zy-SH for qemu-devel@nongnu.org; Fri, 05 Oct 2018 04:38:34 -0400 Date: Fri, 5 Oct 2018 09:38:27 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Message-ID: <20181005083827.GE778@redhat.com> Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20181003091344.24496-1-d.csapak@proxmox.com> <20181004135110.GQ3667@redhat.com> <3672933a-18c4-8283-1318-c7b57fdf08d7@proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <3672933a-18c4-8283-1318-c7b57fdf08d7@proxmox.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 0/1] add exit-script option to qemu List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Dominik Csapak Cc: qemu-devel@nongnu.org, pbonzini@redhat.com On Fri, Oct 05, 2018 at 08:56:27AM +0200, Dominik Csapak wrote: > On 10/4/18 3:51 PM, Daniel P. Berrang=C3=A9 wrote: > > On Wed, Oct 03, 2018 at 11:13:43AM +0200, Dominik Csapak wrote: > > > this patch aims to execute a script when qemu exits > > > so that one can do cleanups when using --daemonize without > > > having to use the qmp monitor > >=20 > > IMHO the idea of cleanup scripts run by QEMU itself is flawed. > > QEMU will inevitably crash before cleanup scripts can be run, > > so whatever mgmt app is using QEMU needs to be able to do > > cleanup without QEMU's help. > >=20 > > I think this can be done more reliably with a wrapper script, > > that spawns QEMU, waits for it to exit and then calls the > > cleanup script. On Linux at least you can use prctl() with > > PR_SET_CHILD_SUBREAPER so you can detect exit'ing of QEMU > > even after it has daemonized. > >=20 > > Perhaps we could have such a wrapper script put in the > > contrib directory > >=20 > > Regards, > > Daniel > >=20 > Hi, >=20 > for cleaning up after qemu crashes, you are completely right, > (ignoring that the downscript for tap devices also never gets executed > then), but this series has another use. >=20 > With it, a user can determine the reason of a graceful shutdown > (e.g., if it was by a signal, qmp or from inside) of qemu, > especially when using -no-reboot without using qmp >=20 > and using qmp for that is not very practical for everyone, > or is there another way for that which i am missing? Honestly QMP *is* the right answer. We've put alot of effort into QMP and I don't think it is sensible to start adding new mechanisms to provide the same information in an adhoc manner. What makes you think QMP isn't practical to use ? We have client impls that talk to QMP in scripts/qmp that are just a few 100 lines of pretty simple python code. Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :|