[libvirt] [PATCH] virsh: Correctly detect inserted media in change-media command

[Michal Privoznik]

https://bugzilla.redhat.com/show_bug.cgi?id=1250331

It all works like this. The change-media command dumps domain
XML, finds the corresponding cdrom device we want to change media
in and returns it in the xmlNodePtr form. This way we don't have
to bother with keeping all the subelements or attributes that we
don't care about in the XML that is fed back to libvirt for the
update API.

Now, the problem is we try to be clever here and detect if disk
already has a source (indicated by <source/> subelement).
However, bare fact that the element is there does not mean disk
has source. The element has some attributes and only if @file or
@dev is within them disk has source. Any other attribute is
meaningless for our purpose now. Make our clever check better.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 tools/virsh-domain.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index d239ba8..8fb4204 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -11055,6 +11055,7 @@ virshUpdateDiskXML(xmlNodePtr disk_node,
     char *device_type = NULL;
     char *ret = NULL;
     char *startupPolicy = NULL;
+    char *source_path = NULL;
 
     if (!disk_node)
         return NULL;
@@ -11111,7 +11112,10 @@ virshUpdateDiskXML(xmlNodePtr disk_node,
     }
 
     if (source) {
-        if (type == VIRSH_UPDATE_DISK_XML_INSERT) {
+        if (!(source_path = virXMLPropString(source, "file")))
+            source_path = virXMLPropString(source, "dev");
+
+        if (source_path && type == VIRSH_UPDATE_DISK_XML_INSERT) {
             vshError(NULL, _("The disk device '%s' already has media"), target);
             goto cleanup;
         }
@@ -11170,6 +11174,7 @@ virshUpdateDiskXML(xmlNodePtr disk_node,
  cleanup:
     VIR_FREE(device_type);
     VIR_FREE(startupPolicy);
+    VIR_FREE(source_path);
     return ret;
 }
 
-- 
2.4.10