Description of problem:

When attempting to register a Xen guest against a Satellite 5 instance, the following error can be observed:

Exception Handler Information
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/spacewalk/server/apacheRequest.py", line 122, in call_function
    response = func(*params)
  File "/usr/share/rhn/server/handlers/xmlrpc/registration.py", line 513, in new_system
    architecture, data)
  File "/usr/share/rhn/server/handlers/xmlrpc/registration.py", line 345, in create_system
    and not rhnVirtualization.is_host_uuid(virt_uuid):
  File "/usr/lib/python2.6/site-packages/spacewalk/server/rhnVirtualization.py", line 839, in is_host_uuid
    uuid = eval('0x%s' % uuid)
  File "<string>", line 1
     0x
      ^

 SyntaxError: invalid token
 
I imagine that it would be possible to encounter this error against upstream RHN as well.

Apparently, it seems that hardware.dmi_system_uuid() can end up returning an empty string thereby breaking the registration process.

/usr/share/rhn/up2date_client/rhnreg.py

def get_fully_virt_info():
    """
    This function looks in the SMBIOS area to determine if this is a 
    fully-virt guest.  It returns a (uuid, virt_type) tuple.
    """
    vendor = hardware.dmi_vendor()
    uuid = hardware.dmi_system_uuid()
    if vendor.lower() == "xen":
        uuid = uuid.lower().replace('-', '')
        virt_type = "fully"
        return (uuid, virt_type)
    else:
        return (None, None)

Notice the UUID value reported by dmidecode on a Xen guest system:
        
Handle 0x0100, DMI type 1, 27 bytes
System Information
        Manufacturer: Xen
        Product Name: HVM domU
        Version: 4.1<denied>
        Serial Number: 00000000-0000-0000-0000-000000000000
        UUID: Not Settable         <====== returns as empty string ''
        Wake-up Type: Power Switch
        SKU Number: Not Specified
        Family: Not Specified

This causes issues for paravirt guests since we may actually never make it to get_para_virt_info()

I'm filing this under RHEL 6 but likely applies to all RHEL releases.


Version-Release number of selected component (if applicable):

rhn-client-tools-1.0.0.1-38.el6


How reproducible:

Easily.


Steps to Reproduce:

1. Register a Xen guest w/ not settable UUID.
2. Let it rain.


Actual results:

SyntaxError: invalid token


Expected results:

No error, able to grab the UUID from /sys/hypervisor/uuid if paravirt


Additional info:

Not comprehensive but good enough...

diff --git a/rhnreg.py b/rhnreg.py
index 7a4735d..18b1e7c 100644
--- a/rhnreg.py
+++ b/rhnreg.py
@@ -222,7 +222,7 @@ def get_fully_virt_info():
     """
     vendor = hardware.dmi_vendor()
     uuid = hardware.dmi_system_uuid()
-    if vendor.lower() == "xen":
+    if vendor.lower() == "xen" and uuid:
         uuid = uuid.lower().replace('-', '')
         virt_type = "fully"
         return (uuid, virt_type)