Fix class DBFilter().output() to pass its unit test with Python3

- Fix Element() takes at least 1 argument (0 given)
- Fix for sax.parseString() arg: TypeError: a bytes-like object is required, not 'str'
- Fix NameError: name 'unicode' is not defined when converting unicode
- Decode bytes to str before using `re` to matching using str patterns

Signed-off-by: Bernhard Kaindl <[email protected]>

xen-bugtool

@@ -71,10 +71,14 @@ import defusedxml.sax
 if sys.version_info.major == 2:
     from commands import getoutput  # pyright: ignore[reportMissingImports]
     from urllib import urlopen  # type:ignore[attr-defined]
+
+    unicode_type = unicode  # pyright:ignore[reportUndefinedVariable] # pylint: disable=unicode-builtin
 else:
     from subprocess import getoutput
     from urllib.request import urlopen
 
+    unicode_type = str
+
 # Fixed in 3.7: https://github.com/python/cpython/pull/12628
 # Monkey-patch zipfile's __del__ function to be less stupid
 #   Specifically, it calls close which further writes to the file, which
@@ -474,7 +478,7 @@ data = {}
 dev_null = open('/dev/null', 'r+')
 
 def no_unicode(x):
-    if isinstance(x, unicode):
+    if isinstance(x, unicode_type):
         return x.encode('utf-8')
     return x
 
@@ -1344,7 +1348,7 @@ class XapiDBContentHandler(xml.sax.ContentHandler):
         if name == "row":
             self._filter(attrs._attrs)
 
-        element = Element(tag=name, attrib=attrs._attrs)
+        element = Element(name, attrib=attrs._attrs)
         self.elements_stack.append(element)
 
     def endElement(self, name):
@@ -1370,11 +1374,12 @@ class DBFilter:
         # remove values for any keys containing the word 'password'
         # example input snippet to filter:
         #   '%.(\'incoming_chappassword\'%.\'TC12818outgoingpasswd\'))" host="Opaq'
+        raw_xml = raw_xml if isinstance(raw_xml, str) else raw_xml.decode()
         nopass_xml = re.sub(r"\('(\w*(?:password)\w*)'%\.'\w*'\)", r"('\1'%.'REMOVED')", raw_xml)
 
         self.content_handler = XapiDBContentHandler()
         try:
-            defusedxml.sax.parseString(nopass_xml, self.content_handler)
+            defusedxml.sax.parseString(no_unicode(nopass_xml), self.content_handler)
         except xml.sax._exceptions.SAXParseException:
             pass  # parse command output line by line, first line just headers
 
@@ -1388,7 +1393,7 @@ def filter_db_pii(s, state):
 
 clipboard_match = re.compile(r'^/local/domain/(\d+)/data/((set)|(report))_clipboard')
 def filter_xenstore_secrets(s, state):
-    match = clipboard_match.search(s)
+    match = clipboard_match.search(s.decode())
     if match:
         return '/local/domain/%s/data/%s_clipboard = <filtered for security>\n' % (match.group(1), match.group(2))
     else: