diff --git a/mercurial/hgweb/hgwebdir_mod.py b/mercurial/hgweb/hgwebdir_mod.py
--- a/mercurial/hgweb/hgwebdir_mod.py
+++ b/mercurial/hgweb/hgwebdir_mod.py
@@ -20,7 +20,6 @@ class hgwebdir(object):
         def cleannames(items):
             return [(name.strip(os.sep), path) for name, path in items]
 
-        self.origconfig = config
         self.motd = ""
         self.repos_sorted = ('name', False)
         if isinstance(config, (list, tuple)):
@@ -48,12 +47,12 @@ class hgwebdir(object):
             self.repos.sort()
 
     def run(self):
-        if os.environ['GATEWAY_INTERFACE'][0:6] != "CGI/1.":
+        if not os.environ.get('GATEWAY_INTERFACE', '').startswith("CGI/1."):
             raise RuntimeError("This function is only intended to be called while running as a CGI script.")
         import mercurial.hgweb.wsgicgi as wsgicgi
         from request import wsgiapplication
         def make_web_app():
-            return self.__class__(self.origconfig)
+            return self
         wsgicgi.launch(wsgiapplication(make_web_app))
 
     def run_wsgi(self, req):