Lenfis bLog » english

Ubuntu, Apparmor and moved home dirs

Jakob — Thu, 17 Jun 2010 07:04:42 +0000

I got a new HDD recently and linked /home to a new partition mounted on /data/, /data/home/. Just like I did a dozen times before. Now a realized, that my pdf viewer evince (and surely some other programs) aren’t working anymore. Evince crashes with this error message:

(evince:22792): EggSMClient-WARNING **: Failed to connect to the session manager: None of the authentication protocols specified are supported
(evince:22792): Gtk-WARNING **: Attempting to read the recently used resources file at `/home/lenfers/.recently-used.xbel', but the parser failed: Datei »/home/lenfers/.recently-used.xbel« konnte nicht geöffnet werden: Permission denied.
** (evince:22792): WARNING **: Error creating last_settings file: Fehler beim Öffnen der Datei »/home/lenfers/.gnome2/evince/last_settings«: No such file or directory

As I found out, that is caused by AppArmor, a surely useful innovation to secure your computer, but new enough that I haven’t took the time to get to know it. AppArmor is activated by default on Ubunut 10.04 (and IIRC 9.10 and maybe 9.04 as well) and restricts access of programs on certain files. Due to the change of my home directory, evince tried to access files which for AppArmor are in /data/home/lenfers/ and consequently disallowed access to them.

The solution to this is easy, after I found it: Make your new location for home directories known to AppArmor: Add the path of your home direcories to the HOMEDIRs var in /etc/apparmor.d/tunables/home. Now the line looks like that for me:

@{HOMEDIRS}=/home/ /data/home/

Now back to work.

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Reaction Buttons and WordPress 3

Jakob — Sat, 12 Jun 2010 07:37:14 +0000

Just made small changes to Reaction Buttons and tested them on a WordPress3 rc3 blog. New features will be in version 1.1.

Download the current version directly through the plugins menu or from wordpress.org.

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VDR hack: Stream video with synced audio

Jakob — Thu, 10 Jun 2010 07:07:19 +0000

VDR streams very well with the streamdev-plugin, but only unicast http streams. That is usually no problem, because even 3 streams aren’t nearly too much for a normal 100Mbit home network and I wouldn’t need any more at home. But with the world cup starting tomorrow me and Karin are going to watch some games that aren’t that interesting to us at the computer while doing other stuff. We did this before, but the downside is that we never got the http stream really synchronized and nothing is more annoying than the same audio stream with a one second delay in one room. (Our solution was to mute one stream, but thats not a real solution because one of us always has to have a asynchronous audio to the video signal.)

My hack I will be using for the world cup the next four weeks is the following: I described how to stream the world cup at your office for all your colleagues a few days ago. I will do that at home too, and then just play that stream, in which the video and the audio are really in sync, at least for my ear. I have to play the stream, because the VDR still has control over the DVB devices and VLC couldn’t open them. And the VLC on my VDR is quite ancient, since I’m using an older version of c’t-vdr.

So, on one computer I start VLC with the following options (all in one line):

cvlc  http://vdr:3000/S19.2E-1-1101-28106  ":sout=#rtp{dst=226.42.42.42,port=5004,mux=ts}"

You can get the URL for each channel from your vdr at http://vdr:3000/channels.html.

And on all the computers that are supposed to view the stream, VLC has to be started with the following command:

vlc rtp://@226.42.42.42:5004/

Sure there is now a slightly higher delay (two streams), but I don’t mind those three seconds when we can watch the games with synced audio. You can get a bit more information about streaming in my world cup streaming post and a lot more in the VLC streaming documentation.

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Just read: Wil Wheatons «Dancing Barefoot»

Jakob — Sat, 15 May 2010 17:58:08 +0000

After having read Wil Wheatons «Just a geek» (about which I wrote a week ago), I thought I’ll also read Wils first book «Dancing Barefoot». If you liked Just a geek, I bet you won’t be disappointed by its predecessor. But to be honest I liked Just a geek more, it felt more personal and told Wils story. Also there are a few (two?) stories told in both books. But I found especially the story about “WILLIAM FUCKING SHATNER” interesting, because I couldn’t understand in Just a geek why Wil is calling him that. Dancing Barefoot tells the associated story.

Oh and from a geeks point of view I found the license quite curious: Creative Commons – Deed Attribution-Noncommercial-No Derivative Works Kudos to that!

http://creativecommons.org/licenses/by-nd-nc/1.0/http://creativecommons.org/licenses/by-nd-nc/1.0/

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Exclude categories in Reaction Buttons

Jakob — Mon, 10 May 2010 19:03:57 +0000

I found some time to check my todo list for reaction buttons and found an old entry about the possibility to exclude posts from a certain category from displaying the Reaction Buttons. Well, now that entry is gone. Grab the new version through the plugin interface within wordpress or download it from wordpress.org.

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Just read: Wil Wheatons «Just a geek»

Jakob — Mon, 10 May 2010 19:00:30 +0000

Last weekend I finished Just a geek by Wil Wheaton. As a Star Trek fan I always enjoy reading literature about the backgrounds and the people behind Star Trek, but this book wasn’t just interesting, I found it also quite educational about life, the universe and everything. Wil wrote a very open book about his life journey after leaving Star Trek – The Next Generation (TNG) and his search for happiness. It seems he didn’t skip the bad parts and decisions he made, but on the other hand is quite entertaining about it.

What I for example didn’t knew before, is that he left Star Trek on his own to pursue his movie career. Since there was a big Anti Wesley Crusher Campaign during TNG, I always assumed that he was written out of the show. I have to admit, I wasn’t a Wesley fan either and wasn’t that unhappy that he left the show, even though I never would have written him a fan hate letter or something like that. But I never really thought about the fact, that it wasn’t his fault: A 16 year old boy has not that much influence with writers/directors/whatever, he had to do what the script told him.

If you are interested in a bit Star Trek history from a unique point of view or perhaps follow Wils blog, this book is surely a good read, I enjoyed it very much.

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Installation via USB

Jakob — Mon, 19 Apr 2010 15:30:06 +0000

I just got some new hardware for my new (or overhauled) vdr. (More on that later…) I wanted to try out yavdr and needed a cd drive for the installation. I looked in my basement for an old drive, finally found one in an old IBM Intellistation and got it out of there. Then I burned the cd, very sloooowly, so the old drive can read it, found a PATA cable to connect the drive and booted. Half through the boot process the drive couldn’t read the cd anymore… All that hassle, just because I seem to be too oldschool to think of usb drives. Since I already got the iso image on my computer, it took around 3 minutes to use usb-creator to create a bootable usb drive. Too easy for me I suppose…

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Widget support for Reaction Buttons

Jakob — Sat, 06 Mar 2010 16:16:42 +0000

I just uploaded a new version of Reaction Buttons, which features a widget now. In that widget you can show the top x posts with the most clicks for each button.

Coding took less time than putting the new version online, since there are a lot of places where you can set a version and they are parsed directly out of svn by some wordpress magic script. I tagged the new release properly in the svn repository and added the version nubmer as stable in the parsed readme.txt. But I forgot to change the version in the main .php file, which seems to be important too. Thanks to #wordpress on irc.freenode.net for pointing that out.

Download from wordpress.org or directly through the install/update function of wordpress.

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Can’t download files from Dokuwiki

Jakob — Tue, 02 Mar 2010 14:12:08 +0000

Recently I found out, that the user documentation videos my colleague made, weren’t shown anymore in our dokuwiki installation and I couldn’t find out why. Everything worked well, pages were shown, but only downloadable media wasn’t. I added a .htaccess for a different project a while ago and allowed them in the apache configuration. But even though I deactivated the new .htaccess file again to test if some of my settings messed with dokuwiki, I still got the following error:

[Tue Mar 02 12:34:14 2010] [error] [client 134.x.y.z] client denied by server configuration: /opt/wiki/data/media/win/printersetup.ogv

What I didn’t knew was, that dokuwiki has some restrictive .htaccess files for file downloads. Just modify them or deactivate .htaccess overrides for dokuwiki again, like I did.

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New Reaction Buttons version

Jakob — Sat, 20 Feb 2010 14:34:34 +0000

Yesterday I finally found some time to include cookies into reaction buttons, so that you could push every button only once. Sure, It’s quite easy to circumvent, but without authentication it’s not possible to prevent that. And authenticating before using the buttons would be against their primary idea.

Download from wordpress.org or directly through the update function of wordpress.

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