dom0/core: check if object has attr before using it

dom0/qvm-core/qubes.py

@@ -778,6 +778,7 @@ class QubesVm(object):
     def get_config_params(self, source_template=None):
         args = {}
         args['name'] = self.name
+        if hasattr(self, 'kernels_dir'):
             args['kerneldir'] = self.kernels_dir
         args['vmdir'] = self.dir_path
         args['pcidev'] = str(self.pcidevs).strip('[]')
@@ -794,10 +795,12 @@ class QubesVm(object):
         args['rootdev'] = self.get_rootdev(source_template=source_template)
         args['privatedev'] = "'script:file:{dir}/private.img,xvdb,w',".format(dir=self.dir_path)
         args['volatiledev'] = "'script:file:{dir}/volatile.img,xvdc,w',".format(dir=self.dir_path)
+        if hasattr(self, 'kernel'):
             modulesmode='r'
             if self.is_updateable() and self.kernel is None:
                 modulesmode='w'
             args['otherdevs'] = "'script:file:{dir}/modules.img,xvdd,{mode}',".format(dir=self.kernels_dir, mode=modulesmode)
+        if hasattr(self, 'kernelopts'):
             args['kernelopts'] = self.kernelopts
 
         return args

dom0/qvm-tools/qvm-prefs

@@ -51,18 +51,25 @@ def do_list(vm):
         print fmt.format ("root COW img", vm.rootcow_img)
     if vm.template_vm is not None:
         print fmt.format ("root img", vm.template_vm.root_img)
+    if hasattr(vm, 'volatile_img'):
         print fmt.format ("root volatile img", vm.volatile_img)
 
+    if hasattr(vm, 'private_img'):
         print fmt.format ("private img", vm.private_img)
     print fmt.format ("vcpus", str(vm.vcpus))
     print fmt.format ("memory", vm.memory)
+    if hasattr(vm, 'maxmem'):
         print fmt.format ("maxmem", vm.maxmem)
+
+    if hasattr(vm, 'kernel'):
         if vm.template_vm is not None:
             print fmt.format ("kernel", "%s (from template)" % vm.kernel)
         elif vm.uses_default_kernel:
             print fmt.format ("kernel", "%s (default)" % vm.kernel)
         else:
             print fmt.format ("kernel", vm.kernel)
+
+    if hasattr(vm, 'kernelopts'):
         if vm.uses_default_kernelopts:
             print fmt.format ("kernelopts", "%s (default)" % vm.kernelopts)
         else:
@@ -309,6 +316,10 @@ def do_set(vms, vm, property, args):
         print >> sys.stderr, "ERROR: Wrong property name: '{0}'".format(property)
         return False
 
+    if not hasattr(vm, property):
+        print >> sys.stderr, "ERROR: Property '{0}' not available for this VM".format(property)
+        return False
+
     return properties[property](vms, vm, args)
 
 
@@ -353,6 +364,7 @@ def main():
             print >> sys.stderr, "You must specify the property you wish to set..."
             print >> sys.stderr, "Available properties:"
             for p in properties.keys():
+                if hasattr(vm, p):
                     print >> sys.stderr, "--> '{0}'".format(p)
             exit (1)