qemu|qtest: Avoid dangerous arguments
The list object is mutable in python and potentially might modify other
object's arguments when used as default argument. Reproducer:
>>> vm1 = QEMUMachine("qemu")
>>> vm2 = QEMUMachine("qemu")
>>> vm1._wrapper.append("foo")
>>> print vm2._wrapper
['foo']
In this case the `args` is actually copied so it would be safe to keep
it, but it's not a good practice to keep it. The same issue applies in
inherited qtest module.
Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20170818142613.32394-3-ldoktor@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
diff --git a/scripts/qemu.py b/scripts/qemu.py
index b45e691..afd98a2 100644
--- a/scripts/qemu.py
+++ b/scripts/qemu.py
@@ -30,7 +30,7 @@
# vm is guaranteed to be shut down here
'''
- def __init__(self, binary, args=[], wrapper=[], name=None,
+ def __init__(self, binary, args=None, wrapper=None, name=None,
test_dir="/var/tmp", monitor_address=None,
socket_scm_helper=None, debug=False):
'''
@@ -46,6 +46,10 @@
@param debug: enable debug mode
@note: Qemu process is not started until launch() is used.
'''
+ if args is None:
+ args = []
+ if wrapper is None:
+ wrapper = []
if name is None:
name = "qemu-%d" % os.getpid()
if monitor_address is None: