[libvirt] [PATCH 2/2] qemu: Regenerate VNC socket paths

[Pavel Hrdina]

On Wed, Apr 27, 2016 at 09:15:16AM +0200, Martin Kletzander wrote:
> On Wed, Apr 27, 2016 at 06:24:43AM +0200, Pavel Hrdina wrote:
> >On Tue, Apr 26, 2016 at 04:34:12PM +0200, Martin Kletzander wrote:
> >> Similarly to what commit 714080791778 did with some internal paths,
> >> clear vnc socket paths that were generated by us.  Having such path in
> >> the definition can cause trouble when restoring the domain.  The path is
> >> generated to the per-domain directory that contains the domain ID.
> >> However, that ID will be different upon restoration, so qemu won't be
> >> able to create that socket because the directory will not be prepared.
> >>
> >> Best viewed with '-C'.
> >>
> >> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1326270
> >>
> >> Signed-off-by: Martin Kletzander <mkletzan at redhat.com>
> >> ---
> >>  src/qemu/qemu_domain.c                             | 21 +++++++++++-
> >>  .../qemuxml2argv-graphics-vnc-autosocket.args      | 22 ++++++++++++
> >>  .../qemuxml2argv-graphics-vnc-autosocket.xml       | 34 +++++++++++++++++++
> >>  .../qemuxml2xmlout-graphics-vnc-autosocket.xml     | 39 ++++++++++++++++++++++
> >>  tests/qemuxml2xmltest.c                            |  7 ++++
> >>  5 files changed, 122 insertions(+), 1 deletion(-)
> >>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-autosocket.args
> >>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-graphics-vnc-autosocket.xml
> >>  create mode 100644 tests/qemuxml2xmloutdata/qemuxml2xmlout-graphics-vnc-autosocket.xml
> >>
> >> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> >> index a2f981043915..d6f704d6f91b 100644
> >> --- a/src/qemu/qemu_domain.c
> >> +++ b/src/qemu/qemu_domain.c
> >> @@ -1659,10 +1659,26 @@ qemuCanonicalizeMachine(virDomainDefPtr def, virQEMUCapsPtr qemuCaps)
> >>  }
> >>
> >>
> >> +static void
> >> +qemuDomainCleanupInternalPaths(virDomainDefPtr def, virQEMUDriverConfigPtr cfg)
> >> +{
> >> +    size_t i = 0;
> >> +
> >> +    for (i = 0; i < def->ngraphics; ++i) {
> >> +        virDomainGraphicsDefPtr graphics = def->graphics[i];
> >> +
> >> +        if (graphics->type == VIR_DOMAIN_GRAPHICS_TYPE_VNC &&
> >> +            graphics->data.vnc.socket &&
> >> +            STRPREFIX(graphics->data.vnc.socket, cfg->libDir))
> >> +            VIR_FREE(graphics->data.vnc.socket);
> >> +    }
> >
> >I would also move the channel socket cleanup code here so we don't have two
> >places doing the same thing.
> >
> 
> That would introduce another loop over devices and one of the main
> points of DevicePostParse is not having to do that.

Yes, I know and still I thing that we should have only one place to cleanup
those socket paths so it could be reused for the migration cleanup.

> 
> >> +}
> >> +
> >> +
> >>  static int
> >>  qemuDomainDefPostParse(virDomainDefPtr def,
> >>                         virCapsPtr caps,
> >> -                       unsigned int parseFlags ATTRIBUTE_UNUSED,
> >> +                       unsigned int parseFlags,
> >>                         void *opaque)
> >>  {
> >>      virQEMUDriverPtr driver = opaque;
> >
> >This isn't enough to fix the managedsave/migration.  The root cause is that we
> >generate wrong migratable XML.  This cleanups the definition before migratable
> >XML is created:
> >
> 
> It is enough, but I agree that's not the root cause.  Even though this
> will fix it when migrating to new libvirt from whatever version, we want
> to be able to do migrate from version with this patch in, so I'll amend that.
> 
> >diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> >index 2e409d4..dc0b035 100644
> >--- a/src/qemu/qemu_domain.c
> >+++ b/src/qemu/qemu_domain.c
> >@@ -2560,6 +2560,7 @@ qemuDomainDefFormatBuf(virQEMUDriverPtr driver,
> >     virCPUDefPtr cpu = NULL;
> >     virCPUDefPtr def_cpu = def->cpu;
> >     virDomainControllerDefPtr *controllers = NULL;
> >+    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
> >     int ncontrollers = 0;
> >     virCapsPtr caps = NULL;
> >
> >@@ -2646,7 +2647,7 @@ qemuDomainDefFormatBuf(virQEMUDriverPtr driver,
> >             }
> >         }
> >
> >-
> >+        qemuDomainCleanupInternalPaths(def, cfg);
> 
> However, we cannot do that because we would erase that from the live
> XML.  What we need to do instead is make sure we don't format that path
> if flags & VIR_DOMAIN_FORMAT_XML_MIGRATABLE is true (or whatever the
> flag name is).
> 
> I'll send a v2 with that

If you look closely at the location where I've put that call, you'll see, that
it's in qemuDomainDefFormatBuf() in "if ((flags & VIR_DOMAIN_XML_MIGRATABLE))"
condition which is exactly what we want.

Pavel

> 
> >     }
> >
> >     ret = virDomainDefFormatInternal(def, driver->caps,
> >@@ -2662,6 +2663,7 @@ qemuDomainDefFormatBuf(virQEMUDriverPtr driver,
> >         def->ncontrollers = ncontrollers;
> >     }
> >     virObjectUnref(caps);
> >+    virObjectUnref(cfg);
> >     return ret;
> > }