[libvirt] [PATCH] virsh: add transient interfaces check for iface-unbridge

[Lin Ma]

iface-unbridge(netcf interface backend) checks multiple interfaces
attaching based on static configuration.
If guests interfaces(says tun/tap devices) are attaching to the bridge,
iface-unbridge doesn't check them, It causes the bridge is removed
although it's in use by other guests.

Please refer to:
https://bugzilla.suse.com/show_bug.cgi?id=813117

Signed-off-by: Lin Ma <lma at suse.com>
---
 tools/virsh-interface.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/virsh-interface.c b/tools/virsh-interface.c
index 5f848b6..63ba5bb 100644
--- a/tools/virsh-interface.c
+++ b/tools/virsh-interface.c
@@ -1040,11 +1040,11 @@ cmdInterfaceUnbridge(vshControl *ctl, const vshCmd *cmd)
     const char *br_name;
     char *if_type = NULL, *if_name = NULL;
     bool nostart = false;
-    char *br_xml = NULL;
+    char *br_xml = NULL, *br_xml_transient_if = NULL;
     xmlChar *if_xml = NULL;
     int if_xml_size;
-    xmlDocPtr xml_doc = NULL;
-    xmlXPathContextPtr ctxt = NULL;
+    xmlDocPtr xml_doc = NULL, xml_doc_transient_if = NULL;
+    xmlXPathContextPtr ctxt = NULL, ctxt_transient_if = NULL;
     xmlNodePtr top_node, if_node, cur;
 
     /* Get a handle to the original device */
@@ -1103,6 +1103,21 @@ cmdInterfaceUnbridge(vshControl *ctl, const vshCmd *cmd)
         goto cleanup;
     }
 
+    /* verify whether there is any transient interface attached to bridge. */
+    if (!(br_xml_transient_if = virInterfaceGetXMLDesc(br_handle, 0)))
+        goto cleanup;
+    if (!(xml_doc_transient_if = virXMLParseStringCtxt(br_xml_transient_if,
+                                          _("(bridge interface definition)"),
+                                          &ctxt_transient_if))) {
+        vshError(ctl, _("Failed to parse configuration of %s"), br_name);
+        goto cleanup;
+    }
+
+    if (virXPathNode("./bridge/interface[2]", ctxt_transient_if) != NULL) {
+        vshError(ctl, "%s", _("The bridge is in use by transient interfaces"));
+        goto cleanup;
+    }
+
     /* Change the type and name of the outer/master interface to
      * the type/name of the attached slave interface.
      */
@@ -1198,10 +1213,13 @@ cmdInterfaceUnbridge(vshControl *ctl, const vshCmd *cmd)
        virInterfaceFree(br_handle);
     VIR_FREE(if_xml);
     VIR_FREE(br_xml);
+    VIR_FREE(br_xml_transient_if);
     VIR_FREE(if_type);
     VIR_FREE(if_name);
     xmlXPathFreeContext(ctxt);
+    xmlXPathFreeContext(ctxt_transient_if);
     xmlFreeDoc(xml_doc);
+    xmlFreeDoc(xml_doc_transient_if);
     return ret;
 }
 
-- 
1.8.4