lostwebsite.net blog

Adobe Air is a new software platform from Adobe which mixes JavaScript and Flash technologies to enable developers to make rich Internet applications that can run on desktop computers. It is remarkable in the world of proprietary applications in the sense that it has included Linux support early on.

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So Skype is evil because it’s proprietary?

It’s not hard to find rumors about spyware being deployed with the Skype VOIP software. What is hard to find amongst those rumors are concrete facts. Most of the rumors seems to be unsubstantiated, and some other are based on interpretation on the EULA of Skype. I won’t bother with the later case since legalese is not a language I speak.

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I find it amazing how your own brain can fool you sometimes. I did not dig this subject very much but I have been intrigues by studies about how people can suggest things to individuals and make them believe in it like it was their own and like it has always been true.

In some circumstances, you can create and believe in your own false memory. This post is about an interesting example of how that has happened to me yesterday night.

At the beginning of the year, I have bought an Asus N10E laptop. It’s a sweet little machine, like a cross between a netbook and a laptop. There is nothing exotic in the configuration of that laptop. The N10 serie of laptops have models that include fancier options. If you look on the net, you will find reviews of the fancier models (see a revew of the N10J). Most of them include a Bluetooth module.

Yesterday, I felt like linking my laptop to my N800 using Bluetooth. I thought it would be like, and that I need needed was to learn how to activate the link and that user-friendly programs would do the rest. I was mistaken. Linux did not detect the Bluetooth device at all. Since I build my own kernel, I decided to check my kernel configuration against other known good configuration for similar models but failed to find anything I would be missing. At that point, I decided to boot back in Windows, thinking I would find more information about Bluetooth there.

At this point, I began to lose patience. Windows had no information about the Bluetooth device in the laptop. I tried reinstalling a few drivers and programs. I even checked the laptop manual, something I seldom do, to see how to activate Bluetooth. It was failure. The normal documented way to activate Bluetooth failed. The Bluetooth device drive was even missing. The BIOS did not have the option to activate or deactivate it.

I began to worry why was my Bluetooth module not working. After all, I had vivid rememberance of the shiny Bluetooth icon displayed on the OSD when I pressed the WLAN hotkey on my laptop.

I first suspected that some experiment I had done in Linux went awry and disabled the Bluetooth module for good, something that could happen by extrapolating from some forums posts on similar problems…

My Occam Razor safety device finally kicked in and I began suspecting I was the source of the problem more than the computer was. After further research, I had to come to this conclusion…

There was probably no Bluetooth module in that laptop!

I write probably for correctness, because the only way to know for sure would mean opening the laptop and search its guts for the Bluetooth chip.

The memory I had of seeing the Bluetooth icon was probably manufactured by my own certitude of that laptop having the Bluetooth option combined with the screen shots of the icon in the laptop manual. The certitude was created by myself using incorrect information since the reviews you can read of this laptop usually talk about Bluetooth, but they usually don’t use of the particular model I own. Some N10E might also have a Bluetooth module pre-installed since it’s an optional feature of the model. Add the fact that the laptop has a Bluetooth led and you have all the ingredients you need to think this laptop would have the Bluetooth module. NCIX, the place from where I ordered the laptop, make no mention of Bluetooth support.

I don’t want to sound overly clever and say I’ve learned my lesson. It’s just too easy to mix up memories with other information. This is just a simple example of what can happen. I feel good about the fact that I was able to sit back and consider that my certitudes might have been fabricated by myself.

I’ve been using the Mercurial Shell Prompt hack for a while until I got annoyed at it. It caused a Python interpeter to start at every prompt, which is expansize especially if your system is already under strain.

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In my last post I’ve shown that some people are annoyed at the fact that they can no longer erase their root directory simply by typing rm -rf /. I’m happy that this possibility is removed. I’m not scared that means Linux is being dumbed down. There are already some safeguards in Linux and nobody is complaining about them because they guard even seasoned users to do things that are dangerous or silly.

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Original post

Did you know that rm -rf / no longer works on recent Ubuntu version? I bet you did not because this command tends to be a bit destructive.

I did not know that. I’ve never been bitten by an accidental rm -rf / but the possibility scares the hell out of me whenever I do a command in my root directory or whenever I write scripts thats erase files.

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I have been looking for database design application on Linux for a while. I even recently started searching for something compatible with Linux through Wine too. The Ubuntu and Debian package database is devoid of anything useful beyond Dia, which I hate for reasons that do not belong to this rant-free blog. There are some tools around for MySQL but it is not the SGDB I’m the most found of. I’m particularily interested in PostgreSQL

It was a revelation to me when I found 2 free (as in beer) design application on the PostgreSQL Wiki. I was even more surprised that both loaded and seemed to work out of the box in just about 30 seconds after their download. I’m not sure about the licensing terms but they certainly look safe to use for FOSS development.

I have not tried either extensively. I just believe both application needs to be linked since they seem to be hard to find. I might review one of them here some day.

Open System Architect

This has an impressive number of button, menus and and various gadgets. It is in fact pretty intimidating at first. It has the feel of a professionally developed application.

It is open-source but sadly does not seem to be actively maintained. This is something I fear I might discover after some prolongued use.

SQLPower Power*Architect

This simple looking application is in Java, which is a showstopper for some people. A good Java application isn’t something that stops me, but I admit Java applications sometimes have problem at setup time if they are not properly packaged.

This application doesn’t have that problem. It run fine when started with a canonical java -jar file.jar command.

The application does look funky a bit on my computer. The fonts are serif and heavily anti-aliased. It look clunky a bit. The screenshots on the site don’t have that problem. It might be a quirk related to my Java distribution or my some font handling problem on my Linux distribution. I need to investigate. That aside, the GUI is simple and no as scary as Open System Architect. If I could fix the font glitch, it will be sweet.

This is also open source. They have a Google Code project.

This little Bash snippets scans the Debian dpkg database for packages whose configurations files have been modified.

This only touches configurations files which are packaged and made known to dpkg. Some package manually handle their configuration file in maintainer scripts. A good example of that is /etc/network/interfaces which is an important configuration file but not automatically handled by dpkg.

This is as useful as you want to make it. I use it to track changes I’ve done which could end up with a conflict during a package upgrade. If you want a more thorough tracking of configuration changes, use something like etckeeper.

Notice I took some care to use more Bash’isms, to optimize the script. I was able to optimize by just a few percents. The bulk of the time must spent calculating MD5 sums.

#!/bin/bash

for pkg in /var/lib/dpkg/info/*.conffiles; do    
    p1=${pkg#/var/lib/dpkg/info/}
    p=${p1%%.conffiles}
    IFS=$'n'
    for cfsum in $(dpkg-query -W -f='${Conffiles}' $p); do
        IFS=' '
        c=($(eval "echo $cfsum"))
        if [ -r ${c[0]} ]; then
            sum=${c[1]}
            cur_sum=($(eval "md5sum ${c[0]}"))
            if [ $sum != ${cur_sum[0]} ]; then
                echo "$p: ${c[0]}"
            fi
        else
            echo "Can't access file: ${c[0]}." > /dev/stderr
        fi
    done
done

This will output something like this:

$ ./check_changed
bash: /etc/bash.bashrc
console-tools: /etc/console-tools/config
libldap2: /etc/ldap/ldap.conf
ntp: /etc/ntp.conf
...

I will not go over the story of the OpenSSL fiasco again. Let’s just say that a developer inserted a particular patch in Debian OpenSSL package that he shouldn’t have. The patch was flawed in ways subtile enough that it escaped review 2 years. Long story short, Debian was left in a rather immense accumulation of fecal matter.

This was bad and made a lot of people object to the fact that software are patched in Linux distributions. It is true that software developers usually are the best person to fix the bugs in their software. What is still true but perhaps less obvious, is that most software developers are not ready or able to work in close cooperation with distribution developers so that their software are perfectly packaged without bugs and in time for a distribution release.

Distribution developers need to patch software for various, good, reasons, to ensure the best quality software distribution to their users, in a timely fashion.

Today I will examine three different kind of patch and try to justify why Debian developers, or distribution developers in general, will develope them. What is very important to note is that Debian, and probably most other distributions, wants that the patch the developers produce are sent to the original developers in the software they are packaging. In the case of the Debian distribution, this is mandated by the Debian Policy Manual, in section 4.3. That way, the patch can be eventually integrated in a future release, and the patch removed for the package for that new release.

The lesser divergence from upstream, the better. The OpenSSL fiasco is certainly a proof of that.

Plain bugfixes

It is a frequent occurance that packages are patched to fix small software bug. It is often inconvenient for a software packager to wait for a new release each time a bug is reported in the software they are responsible of. In some case, that release may come after several months (years), during which the bug will stay unfixed, which may in some case make the package unusable.

Patches are often pulled from the development repository of the software, if they can be backported to the version currently in the distribution.

Debian developers will then patch software when they can, to the best of their knowledge. It is recommended that they consult with the maintainer of the software before uploading their change to the distribution.

Patch example

http://patch-tracking.debian.net/patch/series/view/nano/2.0.7-4/ja_help_freeze.patch

In the case of the nano package, the existance of the patch is documented in the changelog of the package.

Compiler fixes

Like all other package in the distribution, compilers evolve and are eventually upgraded. Debian usually test new compilers ahead of time so they can stamp out compilation bugs early.

In case compilation fails for a package with a new version of a compiler, Debian developers will sometimes prefer to patch the program instead of asking the upstream developer to build his program with a recent or possibly unreleased version of the a compiler. They will patch the program to make it work with the new compiler and transmit the patch to the original developers for their future use.

Patch example

http://patch-tracking.debian.net/patch/series/view/qtodo/0.1.2-5/20-gcc.dpatch

This patch adapts the program to a newer than the one that was probably used to develop the package.

FHS bugfixes

The Debian distribution try to closely follow the Filesystem Hierarchy Standard (FHS). This is actually mandated in the Debian Policy Manual, section 9.1 so, if a program puts a file in a wrong place, it is viewed as a important bug.

Fortunately, most developers will follow the FHS, by habit or consciously. This simplify the packaging process, most program won’t need to be changed to be compliant. Sometimes though, some developers consider that it is not improper that a global configuration file is put outside /etc, or that image files can be put in /var.

Patch example

http://patch-tracking.debian.net/patch/series/view/trac/0.10.3-1etch4/01_use_global_config

This patch tells the Trac web application to look for its configuration file in /etc instead of /usr/share.

That will be enough for today. I think I’m already beyond the “tl;dr” level for most people. I will try to find some more example of types of patch done by packagers in another blog post.

The player

I’ve got this little device recently to replace my 256mb MP3 player. I was pleased that I got it pretty cheap during Black Friday from NewEgg Canada. NewEgg “leaked” their Black Friday rebates to Canada and reduced the price of that player to 85 CAN$ which is pretty cheap for a 8gb model.

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