February, 2008

What can say more than these guys? :-)

FOSDEM 2008 has been a great edition, for me too. I spent most of my time at the BSD+PostgreSQL Developer Room. One nice thing I found out is that EnterpriseDB has a development centre in Islamabad at only a few kilometres from our office and, apparently, we’re both member of the industry advisory board of NUST. Nice meeting you, guys!

It must be said though: the ULB is not the best location for FOSDEM. At least not any more. For several talks, I had to sit on the floor or stand up against the wall at the back of the auditorium. The Mozilla dev room was a named sauna.fosdem.org. The hallway with the project booths was so crowded, it was nearly impossible to take your time to visit the individual projects. I know Brussels has a nice international aura hanging around it, but if you would just turn Leuven into “Brussels East” or something, I’m sure you won’t see the difference in the amount of people showing up. But, dear FOSDEM organisers, at Campus Arenberg III of the K.U.Leuven, I’m sure you can provide all of us a nicer geek experience.

And, oh yes, FOSDEM is not free. I spent over € 100 this weekend on donations only! ;-)

Whoa! Got some really good news yesterday: MyOWnDB made it into the second round of the first edition Plugg! Out of 66 submissions from start-ups out of no less than 18 European countries, we made it into the top 20.

This means that now we will get a 2 minute speaker slot to present our wares to a public of internet specialists, investors and general geeks. 20 times two minutes plus some delay, means one full hour of presentations. Having only two minutes to stand out from the crowd will be no easy task. I guess I’ll have to sing, or wear a pink suit or something… :-)

Anyway, I hope to meet a lot of interesting people at Plugg. We’re very excited about this opportunity, and would like to thank the organisers for providing us, European Web 2.0 start-ups, a chance like this to expand our business opportunities.

See you in Brussels on the 19th of March!

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12	0.2059	14146724	fread ( )	../wp-vimcolor.php:105

I refer to Jan’s smiley system. I like the idea, and tried to implement something similar in [t]csh… with only limited success.

First of all, I needed an equivalent of that bash function inspecting the return value of the previous command and printing a corresponding smiley. [t]csh doesn’t support functions, so I needed an alias. But in aliases, you can’t use if-then-else. Or so I thought. But this works:

Watch your quoting; remember that the shell strips off one level of quoting when you set the alias and another during the first pass of the eval. The echo_style could also be just ``sysv'', but not ``none'' or ``bsd'' if you want some colour instead of a scrambled shell. And, oh yes. Smileys won't work, as there is no way I could make this statement not evaluate ('s or )'s correctly (unless maybe I try it with makealias or quote one day), so I opted for the + and - signs instead.

Now after figuring this out, I needed a way to get an alias call into my $prompt variable. Bummer. No support for this in [t]csh. Yikes!

So now what? Well, you could just set the printexitvalue shell variable to print the exit status of commands which exit with a status other than zero, which is supported by default by [t]csh.

So, the same functionality can be gotten (even far simpler than in bash), but not the same coolness factor. Too bad for those [t]csh users out there. :-)

How to rescue a remote, headless FreeBSD system from a Linux rescue image which cannot mount ufs2 read-write? Impossible, you think? I just did it. :-)

We’re running (amongst others) a FreeBSD 7.0-RC1 installation as a web and mail server. On a sad sad day, I rebooted the machine and ping told me it came up just fine, but nmap told me that there was no way in any more. Hmm..

Our hosting provider has this service which allows us to reboot our servers into a debian rescue image by sending an properly formatted email to a special email address. Of course, from that image, I couldn’t do much to fix the FreeBSD installation on the disk. This is what I did:

1. make an image of the first 100MB of the primary master hard disk
2. copy that image to another server, or your local computer
3. now place a FreeBSD image on the first 100MB of that hard disk (I prepared one with The Depenguinator, version 2.0)
4. reboot
5. log in to the FreeBSD image, which is loaded into memory
6. get back those 100MB you just copied over to a safe place and cat them onto the same hard disk (different device name now of course)
7. mount your FreeBSD installation’s file system hierarchy and try to fix stuff
8. reboot
9. repeat if necessary…

I must say I was a bit nervous and had to concentrate not to accidentally mistype anything or cat or dd stuff onto the wrong place. But hey! It worked out just fine in the end.

I’ve got my BSD machine back. /me happy!

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Call Stack
#	Time	Memory	Function	Location
1	0.0001	52980	{main}( )	../index.php:0
2	0.0002	56420	require( '/home/bbbart/www/htdocs/blog/wp-blog-header.php' )	../index.php:17
3	0.1460	13958028	require_once( '/home/bbbart/www/htdocs/blog/wp-includes/template-loader.php' )	../wp-blog-header.php:16
4	0.1470	14026200	include( '/home/bbbart/www/htdocs/blog/wp-content/themes/svelt/archive.php' )	../template-loader.php:52
5	0.2257	14129620	the_content( )	../archive.php:35
6	0.2261	14131556	apply_filters( )	../post-template.php:167
7	0.2339	14135772	call_user_func_array ( )	../plugin.php:166
8	0.2339	14135956	vim_color( )	../plugin.php:0
9	0.2339	14136292	preg_replace ( )	../wp-vimcolor.php:143
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12	0.2381	14144000	fread ( )	../wp-vimcolor.php:105

( ! ) Warning: fread() [function.fread]: Length parameter must be greater than 0 in /home/bbbart/www/htdocs/blog/wp-content/plugins/vimcolor/wp-vimcolor.php on line 105
Call Stack
#	Time	Memory	Function	Location
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2	0.0002	56420	require( '/home/bbbart/www/htdocs/blog/wp-blog-header.php' )	../index.php:17
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12	0.2425	14143784	fread ( )	../wp-vimcolor.php:105

Today I found out the best way to find out what /var really means on a Gentoo system: I removed it.

Something strange happened. There was a shortage of disk space on the / partition, which also housed /var, so I created /home/var on a different partition, did

, added to /etc/fstab and rebooted into single user mode. There, umounted /var to get back to the original partition (of course, the new fstab-rule as followed already), and rm -rf‘d /var.

So far, so good.

Reboot…

Empty /var!

This means that almost no services can start up (no ssh, no syslog, no portmap, no nothing…) as things like /var/spool, /var/log, /var/run and /var/lock are gone an away…

But what’s worse: /var/www is bye-bye (luckily it contained only localhost-websites) and /var/lib/portage/world as well. Now, portage thinks nothing is installed and wants to re-emerge every tiny little dependency out there. regenworld, I hear you think? Won’t work. /var/log/emerge.log is gone, remember?

Yup, me too:

I wont be there on Saturday though, but you can expect me at the pre-FOSDEM-social-event and on Sunday!

And you know what’s so cool? I can categorise this post in “Business”, “Open Source Adventures” ánd “Life, the Universe, and Everything”. Man, do I love my job! :-)

Today, I filed an application at Plugg for our new baby: MyOwnDB. For those who don’t know yet, Raphaël Bauduin and Zeropoint.IT decided October 2007 to partner in the development and promotion of the best Web based DBMS in the world. Raphaël started with MyOwnDB in the beginning of 2006, but ceased development early 2007. Our partnership will form a company behind MyOwnDB and has gotten the development back up to speed already. Expect a release of the core engine (called δεδομένων) under a Free Software License soon!

And because they asked for it:

:-)

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Call Stack
#	Time	Memory	Function	Location
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6	0.2709	14135096	apply_filters( )	../post-template.php:167
7	0.2743	14140104	call_user_func_array ( )	../plugin.php:166
8	0.2743	14140288	vim_color( )	../plugin.php:0
9	0.2743	14140624	preg_replace ( )	../wp-vimcolor.php:143
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12	0.2798	14153744	fread ( )	../wp-vimcolor.php:105

On our public web server, we are hosting a lot of stuff. Currently, we have over one hundred virtual hosts defined in Apache.

One day, I realised that I didn’t have an overview any more of all these deployments. That’s when I decided to write a simple script to produce me a list of all virtual hosts (and aliases) in HTML. As it’s all about file parsing, and I got a bit bored of Perl, I decided to write it in AWK and wrap it in sh so it can be installed as a CGI script on the same web server.

It’s still really basic, but it serves it’s purpose. Wished feature is to show a difference between ServerName’s and ServerAlias’es. This is left as an exercise to the reader.

Just got back from another nice Geekdinner, in Leuven this time. It was especially pleased to see two of my fellow students again (hello Jan and Koen!). I also got the chance to try one of these things much beloved in the geek community these days: a “plooifiets”. Not sure if it’s something for me though.

Anyway, Wouter convinced me to subscribe to Planet Grep with my still freshly smelling weblog. I guess that’s an honour, so… here we go!

One of the things he said was that “having an audience” might help keeping up the blogging. I don’t really believe this. Although “having an audience” might spur some short-term enthusiasm, I really believe that blogging is something you need to do for yourself. Because you want to do it yourself. Has something to do with internal and external motivators.

Anyway, maybe I should tell “my audience” something now: I don’t allow comments or messages on my blog. It’s my blog after all, isn’t it. If you really feel like reacting, please do! But use your own blog for that and link back to my post’s permalink when doing so. I feel that if it’s too easy to react to my writings on my own space, I will (1) loose too much time keeping up with the comments and probably cleaning up spam and other unwanted things, and (2) more importantly, I guess I’d feel restricted from writing exactly what I want to write. Now, there’s absolutely no reason for me to stay (politically or otherwise) correct!

One last thing. I’ll probably always blog in English, but the odd Dutch or French word might pop up once in a while.

( ! ) Warning: fread() [function.fread]: Length parameter must be greater than 0 in /home/bbbart/www/htdocs/blog/wp-content/plugins/vimcolor/wp-vimcolor.php on line 105
Call Stack
#	Time	Memory	Function	Location
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2	0.0002	56420	require( '/home/bbbart/www/htdocs/blog/wp-blog-header.php' )	../index.php:17
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Had a server crash yesterday. Don’t know if it was due to faulty hardware or something with the OS, but it came at the exact wrong moment.

I was installing OpenBSD 4.2 on a remote system to which I have absolutely no physical access. I created a 64 bit image with qemu on my laptop, installed OpenBSD in it, and deployed it on the remote system. After that, I partitioned and labelled the remote hard disk and started moving /home, /usr and /var from the initial image to their brand new filesystems/partitions.

I fired up $EDITOR to add my new /usr to /etc/fstab and at that exact moment the machine crashed and kicked me out…

No problem you’d say. Just reboot it and continue from there. Think again.

Where does sshd live?