Thursday, May 29, 2008

EPrints, SPAM & deleting users

We run an instance of EPrints 2.3 and noticed recently that it was getting lots of SPAM. Well, more specifically, that a lot of spammers had registered accounts on the system with meaningful usernames like "cunnilingus". Fortunately our self-archiving policy requires that user submissions are approved, but nevertheless the multitude of irrelevent accounts was irritating.

It was then that I discovered that EPrints doesn't have a command-line way to delete users. There's a create_user, but no remove_user. Not being one who is daunted by such problems, I set about writing one. It turned out to be quite simple.

Since I'm a firm believer of making the wheel available, here's what I came up with. YMMV and all that.

posted by guy at: 09:04 SAST | path: /systems | permanent link

Sunday, May 25, 2008

Ubuntu 6.06 LTS to 8.04 LTS on a Xen VPS

I've just upgraded the server hosting this blog from Dapper (6.06 LTS) to Hardy (8.04 LTS). I started by following the instructions, which seemed simple enough.

Unfortunately, as apt started processing the post-install configurations I started seeing a lot of errors Lots of packages (apache, mysql, amavis, etc) had --configure fail with errors like:

Segmentation fault
dpkg: error processing w3m (--configure):
 subprocess post-install script returned error exit status 139

Googling the problem produced this, which suggested the problem was related to the fact that the machine in question was a VPS running under Xen. The suggested solution was to uninstall libc6-i686 and replace it with libc6-xen. Unfortunately I didn't have libc6-i686 installed, and installing libc6-xen didn't help ...

After much head scratching and experimentation, I stumbled across the answer. Or more realistically, I figured out what the failing packages had in common and it triggered a distant memory. All the packages use crypto of some form. SSl or TLS. And I vaugely remember that Xen has a problem with TLS that I had to fix in 6.06.

The suggested solution is to rename /lib/tls to /lib/tls.disabled. I'd already done this in the past (the directory was there as evidence), but the 8.04 upgrade had replaced /lib/tls. Sure enough, removing the directory fixed the problems :-) I then installed libc6-xen, which put in a Xen-friendly /lib/tls.

posted by guy at: 23:58 SAST | path: /systems | permanent link