Today I not only submitted my bachelor thesis to the printing company, I also released a new version of hardlink, my file deduplication tool. hardlink 0.3 now features support for xattr support, contributed by Tom Keel at Intel. If this does not work correctly, please blame him. I also added support for a –minimum-size option. Most of the other code has been tested since the upload of RC1 to experimental in September 2012. ... Read more 》

Today, we worked, with the help of ioerror on IRC, on reducing the attack surface in our fetcher methods. There are three things that we looked at: 1. Reducing privileges by setting a new user and group 2. chroot() 3. seccomp-bpf sandbox Today, we implemented the first of them. Starting with 1.1~exp3, the APT directories /var/cache/apt/archives and /var/lib/apt/lists are owned by the “_apt” user (username suggested by pabs). The methods switch to that user shortly after the start. The only methods doing this right now are: copy, ftp, gpgv, gzip, http, https. ... Read more 》

Since some time, those crappy Fritz!Box devices do not support WDS anymore, but rather a proprietary solution created by AVM. Now what happens if you have devices in another room that need/want wired access (like TVs, Playstations) or if you want to extend the range of your network? Buying another Fritz!Box is not very cost efficient - What I did was to buy a cheap TP-Link TL-WR841N (can be bought for 18 euros) and installed OpenWRT on it. Here’s how I configured it to act as a WiFi bridge. ... Read more 》

Today, I decided to set my X230 back to UEFI-only boot, after having changed that for a bios upgrade recently (to fix a resume bug). I then choose to save the settings and received several error messages telling me that the system ran out of resources (probably storage space for UEFI variables). I rebooted my machine, and saw no logo appearing. Just something like an underscore on a text console. The system appears to boot normally otherwise, and once the i915 module is loaded (and we’re switching away from UEFI’s Graphical Output Protocol [GOP]) the screen works correctly. ... Read more 》

Today I made an important change to the python-apt code: It is now native Python 3 code (but also works under Python 2). The previous versions all run 2to3 during the build process to create a Python 3 version. This is no longer needed, as the code is now identical. As part of that change, python-apt now only supports Python 2.7, Python 3.3, and newer. I’m using some features only present in 3.3 like Python2 unicode literal syntax in order to keep the code simple. ... Read more 》

I released python-apt 0.9. This completely removes support for the old API from the code base (it was disabled for the entirety of 0.8 in Debian, and in Ubuntu since saucy). Highlights: * Cleanup: Complete removal of old-api support code * Bug fix: Various coverty bug fixes by Michael Vogt * Bug fix: Correctly handles multi-arch dependencies in apt.debfile, so packagekit and gdebi can now install local multi-arch packages correctly * Bug fix: A segmentation fault has been fixed. When releasing the value of the policy attribute of an apt_pkg.Cache object, its destructor deleted the pkgPolicy, but that was managed by a CacheFile from APT, causing it to be deleted twice. * Bug fix: Tests do not depend on the contents of /tmp anymore * Bug fix: All examples and old tests have been updated to the current python-apt API * Feature: Paths can now be specified using ‘bytes’ objects instead of ‘str’ in Python 3. * Ubuntu-specific: Meta-data for Ubuntu 14.04 – although with a typo (’thar’ instead of ’tahr’), but that is fixed in git ... Read more 》

This week, a few hours after Lenovo announced the X240, I bought an X230. Normally, the X230 model I bought comes with a Core i5-3320M CPU, 4GB RAM, 500GB HDD. My model was a special set including a second 4GB RAM stick and a 128 GB mSATA Plextor SSD. It came without Windows; and the ThinkVantage button is black instead of blue and has no label. I put a fresh installation of unstable on it and tweaked it to save more power when on battery (enabled RC6++, and enabled autosuspend and other powertop suggestions with a script in /etc/pm/power.d); and configured hdparm.conf to put my hard disk into standby after 5 seconds (it’s only used for big data anyway, so most of the time it is unused). It now consumes 5W in idle with minimum brightness, and 8-10W with brightness 13 of 15. Consumption when surfing is 10 - 15 watts. Booting from grub to gdm is fast, I did not measure it, but it probably took about 5 seconds. ... Read more 》

The script apt-show-versions is developed by another Debian Developer called Christoph Martin in Perl. Recently, it turned out that apt-show-versions is too slow for some users; so I decided to rewrite his program using APT’s C++ API. I expect this to be part of a future APT release, rendering the original apt-show-versions obsolete. The rewrite is sadly not 100% backwards compatible to the original version; as some option names had to be renamed due to our command-line parser not supporting option names like -nh, and some other options were dropped because they are hard to support (like –status-file and –lists-dir) with our command-line parsing. I also decided not to keep the the -p and -r options, but use the standard APT command-line conventions insteads. ... Read more 》

Writing recursive descent parsers is easy, especially in Python (just like everything is easy in Python). But Python defines a low limit on the number of recursive calls that can be made, and recursive descent parsers are prone to exceed this limit. We should thus write our parser without real recursion. Fortunately, Python offers us a way out: Coroutines, introduced in Python 2.5 as per PEP 342. Using coroutines and a simple trampoline function, we can convert every mutually recursive set of functions into a set of coroutines that require constant stack space. ... Read more 》

You can use a PBO solver to clean up your system from unneeded automatically installed packages. First of all, you convert the system state to PB, and add an optimization function telling it to remove as many automatically installed packages as possible. Then you run this thing through a solver (such as clasp, which seems the fastest solver for PBO instances in the Debian archive) and convert its output to human-readable package names. ... Read more 》