Now that StreamRequestHandler defaults rfile to buffered, make it

unbuffered (by setting the class variable rbufsize to 0), because we
(may) need to pass the file descriptor to the subprocess running the
CGI script positioned after the headers.

Lib/CGIHTTPServer.py

@@ -35,6 +35,10 @@ class CGIHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
 
     """
 
+    # Make rfile unbuffered -- we need to read one line and then pass
+    # the rest to a subprocess, so we can't use buffered input.
+    rbufsize = 0
+
     def do_POST(self):
         """Serve a POST request.