Monthly Archives: February 2008

libapache2-mod-xsendfile – processes X-SENDFILE headers with apache2

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For some projects I had to figure out a way to deliver a file via Apache2 but still being able to put some business logic before the download. Imagine you have a php, perl, rails, ruby or whatever project and want to check credentials before delivering a file while not blocking your application with submitting large amounts of data. Lighttpd has a mechanism called “xsendfile” for this. To make it short, this looks for a X-Sendfile header sent by the application. If this header is set and directs to a file the web server stops processing its script and starts delivering a file.

Fortunately there is a promising Apache2 port for this: mod-xsendfile. As I had to compile this serveral times and did not find it in Debian unstable or Ubuntu I made it my first packaging attempt (after having attended the first German Packaging Jam held by Daniel Holbach – thank you!).

If you like, you can test the module for hardy by enabling my ppa archive:

deb http://ppa.launchpad.net/damokles/ubuntu hardy main
deb-src http://ppa.launchpad.net/damokles/ubuntu hardy main

and “aptitude install libapache2-mod-xsendfile” afterwards. See the website for reference. I will also upload this to my ppa for stable releases within the next days.

There is a launchpad bug I created for this. Feel free to test the module and the package and add comments there or directly here. Sadfully this package is to late to be integrated into hardy, so maybe the Intrepid Ibex (what a name…) will be a good milestone.

fast installation of apc php optimizer/cache on Debian / Ubuntu

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If you want a fast installation of the php apc bytecache/optimizer for PHP5/Apache2, try the following snippet when already running a standard PHP5/Apache2 environment:

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# install dependencies for compilation
$ sudo aptitude install apache2-dev php5-dev build-essential
# get current version of apc - check if there is a newer one!
$ wget http://pecl.php.net/get/APC-3.0.16.tgz
$ tar xzf  APC-3.0.16.tgz
$ cd  APC-3.0.16
$ phpize
$ ./configure --enable-apc --enable-apc-mmap \
  --with-apxs=/usr/bin/apxs2 \
  --with-php-config=/usr/bin/php-config
$ make
$ sudo make install
# in /etc/php5/apache2/php.ini add: extension=apc.so
$ sudo apache2ctl restart

No a phpinfo(); should show you a new apc section.

Joining an Active Directory domain with Ubuntu

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What a pain. Imagine you are in Windows network environment and have a small amount of Ubuntu desktops. You task is to let them join the Active Directory so users can login with their known credentials. There is a package in universe called “authtool” even providing and promising to do what you need. Sadfully it is quite broken in it’s current status and if you ask me one should even consider removing it until it does at least not break you boot (don’t ask for details) and has a good set of working dependencies. There are other methods as ldap-binding but in my eyes there are either not stable or just too complicated to configure (and therefore hardly qualified for convincing people).

But a solution approaches if you read the following Ubuntu blueprint “Single User Interface to Join and Participate in Microsoft Active Directory Domains“. Currently you might not find much more information about it. So I dropped a line to the blueprint creator Gerald ‘Jerry’ Carter who was so kind of updating me with the current status of the project (and happens to be directly involved in Likewise):

It is planned to package the open source version of Likewise called “Likewise Open” for Ubuntu Hardy. Likewise Open enables you to join an Active Directory with actually some simple clicks or one console command. There is already an updated source tarball which can be installed quite easily:

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$ wget \http://archives.likewisesoftware.com/\
likewise-open/src/likewise-open-4.0.4.tar.gz
$ tar zxf likewise-open-4.0.4.tar.gz
$ cd likewise-open-4.0.4-release
$ make dpkg

If you have all necessary dependencies resolved the make process should provide you with .deb files which you should install. As Jerry states there is currently one blocker which can be worked by not using the gui but calling a line like this

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$ sudo domainjoin-cli join AD_REALM ADMIN_ACCOUNT

Afterwards you should be able to login like this “realm\username”. I tried the process on Gutsy and it worked quite well. I had to reboot once as my gdm hang – maybe it’s better to call the command directly from a “real” console. So what is missing? Check the comparison of Likewise Open and Likewise Enterprise, the commercial version of Likewise. The thing you might miss at first is:

Do more during logon: Create a home directory, copy template files, set permissions, run scripts, deliver messages, and more.

This means that Likewise Open enables you to login as AD user, creates his home under /local/AD_REALM/USER but you have be smart and hack around a bit to get things working like managing sudo, running scripts and so on. But nonetheless Likewise Open seems to be a promising approach for solving the problem of Ubuntu-Windows-network integration and I am sure to see some nice addons from the community in the future.

Please note: Installing software that changes login procedures is a deep intervention into Linux core procedures. So please: Do this with a test environment before considering it for production purposes.

new kernel release detection snippet

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Just a small and old snippet that might be helpful or an example: Some years ago I’s in need of getting to know early about new released Linux kernel versions. Therefore I wrote a (not sophisticated but working) crontabbed script checking the kernel page for a new stable Linux kernel and alerting me via mail if a new version is found with link to the changelog:

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#!/bin/bash
CURRENTVERSION=`w3m -dump \
 http://www.kernel.org/kdist/finger_banner \
 | head -n 1 | awk '{print $10}'`
SAVEDVERSION=`cat ~/bin/kernelversion.log \
 | tail -n 1 | awk '{print $2}'`
SAVEDDATE=`cat ~/bin/kernelversion.log \
 | tail -n 1 | awk '{print $1}'`
MAILADDRESS=mail@address.tld
 
if [[ "$CURRENTVERSION" != "$SAVEDVERSION" ]]
  then
  CURRENTDATE=`date +'%Y-%m-%d'`
  echo "$CURRENTDATE $CURRENTVERSION" \
  >> ~/bin/kernelversion.log
  echo -e "Detected new kernel version \
   ${CURRENTVERSION} on ${CURRENTDATE} \
   (replacing version ${SAVEDVERSION} from\
   ${SAVEDDATE}). Please check \
   http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-\
   ${CURRENTVERSION} forr details." \
 | mail -s "new kernel ${CURRENTVERSION}" \
 ${MAILADDRESS}
fi

The only real bug in this script is that it does not detect network issues and therefore alerts you when it is not able to get a http response. But this could be fixed with one or two lines of code. And yes most lines could be more elegant :) Probably today there are better channels like rss or even an old mailing list with announcements that I never looked for, but this snippet does it’s job very well.

update:

Fixed the broken wrapping of the script. Sorry about this. (Thank you Jeremy.)

Jonne stated that of course using a feed like http://kernel.org/kdist/rss.xml is the better choice today. He is surely right about this  though sometimes receiving a mail is a need.

Call for Papers: Ubuntu Hardy Heron Release Party (Berlin)

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As already mentioned the “Ubuntu Berlin” user group already planned it’s Ubuntu Hardy Heron release party for 26th of April. This time we want to go one step further and extend our lecture track. Therefore we started a call for papers. The call itself is in German due to our local focus. If you live around Berlin and are willing and able to speak about a Ubuntu- oder Linux-related topic – let us know! The most recent version of the call and a pdf version are to be found on: http://www.ubuntu-berlin.de/hardy-cfp/

For the lazy ones around, take the following:

Call for Papers

Ubuntu Hardy Heron Releaseparty (Berlin)

Die Anwendergruppe “Ubuntu Berlin” sucht Referenten für die am 26.4.2008 in den Räumen des c-base e.V. stattfindende Ubuntu Hardy Heron Releaseparty.

Die Teilnehmer der Party setzen sich aus Ubuntu-Neulingen, Anwendern und fortgeschrittenen Entwicklern zusammen. Es ist mit einer Teilnehmerzahl ab 100 Personen zu rechnen. Thematisch sind Vorträge zu Ubuntu-bezogenen Themen (Neuerungen in Hardy Heron, Ubuntu, Kubuntu, Xubuntu, Edubuntu, Gobuntu, usw.), Installation, speziellen Anwendungsfällen und Applikationen, aber auch Community- und Linux-nahen Aktivitäten willkommen. Die Vortragszeit beträgt 20 Minuten, um ein Vortragsinterval von 30 Minuten einzuhalten. Beamer, Internetzugang, Rechner, Mikrofon können gestellt werden. Bei rechtzeitiger Anfrage ist eventuell die Bereitstellung eines Workshop-Raums für kleinere Sitzungen möglich (ca. 8 Plätze).

Vorschläge sind einzureichen bis zum 29.2.2008. Über eine Annahme der Vorträge wird bis 16.3.2008 entschieden.

Beim Einreichen sind folgende Vorgaben zu beachten:

  • Nennung von Vortragstitel, Name des Vortragenden, Qualifikation (z.B. Anwender, Vereinsmitglied, Entwickler)
  • Beschreibung des Vortragsthemas in einem Absatz
  • Kontakt-Möglichkeit des Vortrages (E-Mail, nach Möglichkeit Telefon)
  • Nennung notwendiger Ressourcen (Beamer, Netzwerk, Rechner)
  • Besteht die Möglichkeit, den Vortrag ca. eine Woche vorher voraufzuführen

Ubuntu Berlin kann keine Kostenerstattung für Anreise, Unterkunft und Verpflegung übernehmen. Ein eventuell notwendiger Transport von Hardware kann im Raum Berlin organisiert werden.

Vortrags-Konzepte und Fragen sind per E-Mail zu richten an
kontakt@ubuntu-berlin.de

Richard Stallman on 18.2. in Berlin

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Just wanted to let you that Richard Stallman helds a lecture in Berlin/Germany on 18th of February.

Here is the German announcement:

Richard Stallman, der Begründer und Vordenker der Freien Software Bewegung hält einen Vortrag über die Philosophie und Geschichte der Freien Software.

Der in New York lebende Richard Stallman ist der Begründer der Freien Software-Bewegung und Verfasser wegweisender Texte dieser Bewegung. Der Begriff der “Freien Software” stammt von ihm und steht für die Idee, dass Software von ihren Benutzern zu jedem Zweck ausgeführt, verändert und weiterentwickelt werden kann und darf. Dieses Recht – das die meisten Software-Firmen ihren Nutzern verweigern – begründet Stallman mit der Forderung, dass Wissen jedem Menschen frei zugänglich sein sollte. Stallman vergleicht das von ihm geforderte Recht auf Freie Software (free software) mit dem Recht der “Freien Rede” (free speach), die im Gegensatz zum “Freibier” (free beer), zu den Grundrechten einer freien Gesellschaft gehört.

Richard Stallman hat mit dem Betriebssystem GNU/Linux auch die Entwicklung des heute am weitesten verbreiten Betriebssystem vorangetrieben, das unter einer freien Lizenz steht. Mit der der GNU General Public Licence hat er darüber hinaus die rechtliche Grundlage für die Nutzung und Verbreitung Freier Software geschaffen. Um die Idee der Freien Software zu kommunizieren und zu verbreiten gründete Richard Stallman 1985 die Free Software Foundation (FSF), die mittlerweile auch Schwesterorganisationen in Europa (FSFE), Indien (FSFI) und Lateinamerika (FSFLA) hat.

Die Veranstaltung beginnt um 19:00 Uhr und findet im Atrium des media centre, Johannisstraße 20, 10117 Berlin statt.

Der Eintritt kostet 5 Euro.

More information can be found on the newthinking website and on the netzpolitik.org blog. See you there?