When libvirtd is started we call qemuDomainRecheckInternalPaths
to detect whether a domain has VNC socket path generated by libvirt
based on option from qemu.conf.  However if we are parsing status XML
for running domain the existing socket path can be generated also if
the config XML uses the new <listen type='socket'/> element without
specifying any socket.

The current code doesn't make difference how the socket was generated
and always marks it as "fromConfig".  We need to store the
"autoGenerated" value in the status XML in order to preserve that
information.

The difference between "fromConfig" and "autoGenerated" is important
for migration, because if the socket is based on "fromConfig" we don't
print it into the migratable XML and we assume that user has properly
configured qemu.conf on both hosts.  However if the socket is based
on "autoGenerated" it means that a new feature was used and therefore
we need to leave the socket in migratable XML to make sure that if
this feature is not supported on destination the migration will fail.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 src/conf/domain_conf.c | 17 ++++++++++++++++-
 src/qemu/qemu_domain.c |  3 ++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 97d42fe993..db1890f8a7 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -11543,6 +11543,7 @@ virDomainGraphicsListenDefParseXML(virDomainGraphicsListenDefPtr def,
     char *network = virXMLPropString(node, "network");
     char *socketPath = virXMLPropString(node, "socket");
     char *fromConfig = virXMLPropString(node, "fromConfig");
+    char *autoGenerated = virXMLPropString(node, "autoGenerated");
     char *addressCompat = NULL;
     char *socketCompat = NULL;
     const char *graphicsType = virDomainGraphicsTypeToString(graphics->type);
@@ -11662,6 +11663,17 @@ virDomainGraphicsListenDefParseXML(virDomainGraphicsListenDefPtr def,
         def->fromConfig = tmp != 0;
     }
 
+    if (autoGenerated &&
+        flags & VIR_DOMAIN_DEF_PARSE_STATUS) {
+        if (virStrToLong_i(autoGenerated, NULL, 10, &tmp) < 0) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("Invalid autoGenerated value: %s"),
+                           autoGenerated);
+            goto error;
+        }
+        def->autoGenerated = tmp != 0;
+    }
+
     ret = 0;
  error:
     if (ret < 0)
@@ -11671,6 +11683,7 @@ virDomainGraphicsListenDefParseXML(virDomainGraphicsListenDefPtr def,
     VIR_FREE(network);
     VIR_FREE(socketPath);
     VIR_FREE(fromConfig);
+    VIR_FREE(autoGenerated);
     VIR_FREE(addressCompat);
     VIR_FREE(socketCompat);
     return ret;
@@ -22894,8 +22907,10 @@ virDomainGraphicsListenDefFormat(virBufferPtr buf,
         virBufferEscapeString(buf, " socket='%s'", def->socket);
     }
 
-    if (flags & VIR_DOMAIN_DEF_FORMAT_STATUS)
+    if (flags & VIR_DOMAIN_DEF_FORMAT_STATUS) {
         virBufferAsprintf(buf, " fromConfig='%d'", def->fromConfig);
+        virBufferAsprintf(buf, " autoGenerated='%d'", def->autoGenerated);
+    }
 
     virBufferAddLit(buf, "/>\n");
 }
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index c187214dc3..2bd6affe33 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2541,11 +2541,12 @@ qemuDomainRecheckInternalPaths(virDomainDefPtr def,
             /* This will happen only if we parse XML from old libvirts where
              * unix socket was available only for VNC graphics.  In this
              * particular case we should follow the behavior and if we remove
-             * the auto-generated socket base on config option from qemu.conf
+             * the auto-generated socket based on config option from qemu.conf
              * we need to change the listen type to address. */
             if (graphics->type == VIR_DOMAIN_GRAPHICS_TYPE_VNC &&
                 glisten->type == VIR_DOMAIN_GRAPHICS_LISTEN_TYPE_SOCKET &&
                 glisten->socket &&
+                !glisten->autoGenerated &&
                 STRPREFIX(glisten->socket, cfg->libDir)) {
                 if (flags & VIR_DOMAIN_DEF_PARSE_INACTIVE) {
                     VIR_FREE(glisten->socket);
-- 
2.11.1

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On Mon, Feb 27, 2017 at 17:31:05 +0100, Pavel Hrdina wrote:
> When libvirtd is started we call qemuDomainRecheckInternalPaths
> to detect whether a domain has VNC socket path generated by libvirt
> based on option from qemu.conf.  However if we are parsing status XML
> for running domain the existing socket path can be generated also if
> the config XML uses the new <listen type='socket'/> element without
> specifying any socket.
> 
> The current code doesn't make difference how the socket was generated
> and always marks it as "fromConfig".  We need to store the
> "autoGenerated" value in the status XML in order to preserve that
> information.
> 
> The difference between "fromConfig" and "autoGenerated" is important
> for migration, because if the socket is based on "fromConfig" we don't
> print it into the migratable XML and we assume that user has properly
> configured qemu.conf on both hosts.  However if the socket is based
> on "autoGenerated" it means that a new feature was used and therefore
> we need to leave the socket in migratable XML to make sure that if
> this feature is not supported on destination the migration will fail.
> 
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  src/conf/domain_conf.c | 17 ++++++++++++++++-
>  src/qemu/qemu_domain.c |  3 ++-
>  2 files changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 97d42fe993..db1890f8a7 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -11543,6 +11543,7 @@ virDomainGraphicsListenDefParseXML(virDomainGraphicsListenDefPtr def,
>      char *network = virXMLPropString(node, "network");
>      char *socketPath = virXMLPropString(node, "socket");
>      char *fromConfig = virXMLPropString(node, "fromConfig");
> +    char *autoGenerated = virXMLPropString(node, "autoGenerated");
>      char *addressCompat = NULL;
>      char *socketCompat = NULL;
>      const char *graphicsType = virDomainGraphicsTypeToString(graphics->type);
> @@ -11662,6 +11663,17 @@ virDomainGraphicsListenDefParseXML(virDomainGraphicsListenDefPtr def,
>          def->fromConfig = tmp != 0;
>      }
>  
> +    if (autoGenerated &&
> +        flags & VIR_DOMAIN_DEF_PARSE_STATUS) {
> +        if (virStrToLong_i(autoGenerated, NULL, 10, &tmp) < 0) {
> +            virReportError(VIR_ERR_XML_ERROR,
> +                           _("Invalid autoGenerated value: %s"),
> +                           autoGenerated);
> +            goto error;
> +        }
> +        def->autoGenerated = tmp != 0;
> +    }
> +

autoGenerated is bool and should be stored as such in the XML. I don't
think we need to copy the bad design from the past even if the result is
going to be inconsistent since this only affects our status XML.

Jirka

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