therning.org/ magnus

I enjoyed reading this article on how an XSS attack works. I’ve always just done the alert("Game over!") XSS which isn’t really an attack at all, just a proof that there’s a possibility for an attack.

That trusted computing is bad for consumers is something I’ve known for a while, but apparently TC is bad for security as well. Every security measure has its side effects, I’m not convinced this one is unintended though.

Here’s a prime example of just how bad laws like DMCA can be. If this holds up we basically allow the law to force us backwards in time. (I just have to sneak in Cory’s excellent write-up on Europe’s broadcasting flag here.)

Network neutrality is a complicated subject. Ed Felten has done a lot lately to clarify things for me with his Nuts and Bolts of Network Neutrality. I still have to find the time to look through his blog a bit more carefully.

Why is this such big news? An update for Ubuntu broke X. Boohoo! I bet most people complaining don’t have a shadow of a leg to stand on in this. They don’t pay, they don’t contribute, they only bitch in the forums/mailinglists/blogs/etc. It only took 8 hours to fix!

Just in case the UK government wants a good reason to not introduce bloody ID cards and national databases to keep records of everything everyone does—here it is!

Looking to replace M$ Office? Here are a few MS Office killers.

I wouldn’t mind having my desktop look like this!

I’ve actually wondered how to uniquify a list in Python for a long time.

Python is moving up, or maybe it’s down, I don’t know.

Want to learn Python and PyGTK? This blog on learning Python seems like a good place to get inspired.

It just didn’t feel right to have KeySafe use a Windows-style INI file for its configuration so I started looking into using GConf instead.

There are good introductions to GConf here and here. Translating it all to Python is simple thanks to the brilliant people who gave us Gnome-Python.

I wrote this code for viewing the setting of the desktop background’s filename:

#! /usr/bin/python

import gtk
import gtk.glade
import gconf

class GConfViewer:
    def __init__(self):
        gui = gtk.glade.XML('Viewer/viewer.glade')
        self.entry = gui.get_widget('entry')

        client = gconf.client_get_default()
        client.add_dir('/desktop/gnome/background',
                gconf.CLIENT_PRELOAD_NONE)
        client.notify_add('/desktop/gnome/background/picture_filename',
                self.new_background)
        self.new_background(client)
        gui.get_widget('window').show_all()

    def new_background(self, client, *args, **kwargs):
        filename = client.get_string(
                '/desktop/gnome/background/picture_filename')
        self.entry.set_text(filename)

if __name__ == '__main__':
    GConfViewer()
    gtk.main()

I really like the client-server nature of it. A short explanation:

1. Get the default GConf client.
2. Add directories.
3. Tell it to watch a specific key, specifying a callback method to be called when its value is changed.
4. Define the callback method.

I also wrote code to change the value of a key:

#! /usr/bin/python

import gconf

def set_bool_key(key):
    client = gconf.client_get_default()
    client.set_bool(key, 1)

if __name__ == '__main__':
    set_bool_key('/desktop/gnome/background/draw_background')

Quite self-explanatory, isn’t it?

The next step in development would be to create a schema for the keys. Both introductions above contain pointers on how to write schemas, for more pointers just take a look in /usr/share/gconf/schemas/. The only problem I ran into was registering the schema. The following commandline does the trick:

GCONF_CONFIG_SOURCE=$(gconftool-2 --get-default-source) \
gconftool-2 --makefile-install-rule keysafe.schemas

Of course the kind Debian developers have done their best to shield packagers from nitty-gritty details. CDBS didn’t just work, it seems to make assumptions about the build system of the package (assuming it’s using auto-tools). Just making sure that the schema ends up in usr/share/gconf/schema during package binary-install, then call dh_gconf -ppackage in binary-post-install/package did the trick.