emojis – an universal language

October 16th, 2014 1 comment

Why was this emoji rejected from being included in UTF? ;-)

Sad Bone Saw

Here’s a list of seeminlgy rejected emojis: rejectedemojis.tumblr.com

Categories: fun, nerdcore Tags:

RESTful APIs and Python

September 16th, 2014 No comments
Categories: software Tags: ,

Secret Coders

September 5th, 2014 No comments

Really nice graphic novel about how to learn coding.

http://www.wired.com/2014/09/secret-coders-gene-yang

Categories: Uncategorized Tags:

adding pci device to vm

August 27th, 2014 No comments

If you want to use a pci device in a vm, you first have to detach it from the host. List the devices and look for the one you want to use in the vm:

virsh nodedev-list --tree

In my case (CentOS7) I needed to enable iommu in order for this to work. This involves adding a kernel parameter:

kpath=`grubby --default-kernel`
grubby --update-kernel=$kpath --args="intel_iommu=on”
cat /proc/cmdline

After the reboot, /proc/cmdline should now include the iommu flag. Also check whether all the needed modules are loaded, in my case these are:

  • vfio_pci
  • vfio_iommu_type1
  • vfio
  • kvm_intel
  • kvm

You can then detach the pci device:

virsh nodedev-dettach pci_0000_05_00_1

I then used virt-manager, powered off the vm, and added the “Physical Host Device”.

Categories: Uncategorized Tags:

virt-manager as non-root user

August 26th, 2014 No comments

trying to start virt-manager as a normal user will yield a “Unable to open a connection…” message. To fix this, we need to change access permissions for libvirtd.

Edit /etc/libvirt/libvirtd.conf:

echo "unix_sock_group = \"libvirt\"
unix_sock_rw_perms = \"0770\"
auth_unix_rw = \"none\"
">>/etc/libvirt/libvirtd.conf

We also jneed to create the group “libvirt” we just set:

groupadd -g $GID libvirt; usermod -a -G libvirt $USER

Be sure to set $GID and $USER correctly.

A restart of the daemon should then do the trick:

service libvirtd stop; service libvirtd start

if virt-manager the shows only squares instead of letters, install the necessary fonts:

yum -y groupinstall "Fonts"

Categories: Uncategorized Tags:

SQLite rowid picking joke….ehm algorithm

July 22nd, 2014 No comments

I laughed very hard at this:

“The usual algorithm is to give the newly created row a ROWID that is one larger than the largest ROWID in the table prior to the insert. If the table is initially empty, then a ROWID of 1 is used. If the largest ROWID is equal to the largest possible integer (9223372036854775807) then the database engine starts picking positive candidate ROWIDs at random until it finds one that is not previously used. If no unused ROWID can be found after a reasonable number of attempts, the insert operation fails with an SQLITE_FULL error.”

Source: sqlite.org

Categories: fun, nerdcore, software Tags: ,

heartbleed

April 8th, 2014 1 comment

Enough word already on all channels, here’s a short one-liner to check which procs are still using the vulnerable old libs after the upgrade:
sudo lsof -n | grep ssl | grep DEL

Oh, and if you want to test wether a site is still vulnerable: https://gist.github.com/takeshixx/10107280

Time to revoke all those lingering server certs . . .

Categories: Uncategorized Tags:

pbpaste and pbcopy in tmux (and screen) on mac os x

March 27th, 2014 2 comments

the pasteboard tools do not work in tmux on a mac. But there is a tool to fix this (of course ^^):
brew install reattach-to-user-namespace

Then, in your .tmux.conf, add this:
set-option -g default-command "reattach-to-user-namespace -l zsh"
– more info on how to configure can be fiound here: https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard/blob/master/Usage.md

After restarting your tmux server, pbcopy and pbpaste should work again.

Categories: Uncategorized Tags:

Debian + Icedove + Owncloud

March 27th, 2014 2 comments

Intro
As many others I have to sync my contacts and calendar between several systems. Since I have no Apple products and don’t want to donate my private data to Google, I found owncloud as the best solution covering my needs. Debian and Gnome have been allies for a long time now so I coupled the Evolution mail client with my owncloud instance. The last weeks were a little tricky due to several issues in my mail client (damaged encrypted mails, hung ups, excessive ressource consumption…) on Debian Jessie. After reaching peak annoyance level, it was time for a change.

Part I – The Mail Client
The only useful alternative known to me is Thunderbird. In the past I got to know Thunderbird as a very nice, fast, and powerful piece of software. Debian re-brands it to Icedove which can be installed using APT. To me as a Chromium user it looks quite familiar and exhibits a huge performance increase towards Evolution. Nice…
Next thing was to get my calendar into Icedove. Usually, I don’t like bloated software and prefer small, fast tools one for each task. The Exceptions to me are development suits and mail clients. Having all the important information bundled in on place is a nice thing. Thunderbird got the Lightning plugin, a great ‘little’ helper to manage dates within Thunderbird. Unfortunately, the integrated plugin interface of Icedove doesn’t work with (all?) Thunderbird plugins, so beware of using the integrated Extensions/Add-Ons menu! My first attempt lead to a crashing mail client on it’s startup with the following error message (when startet on the console) and seems to be a known Bug:

…version xul24.0 not defined in file libxul.so with link time reference…

On Debian one has to install Iceowl-extension, which basically is the Lightning plugin for Icedove, via APT and all is fine.

Part II – Owncloud and Remote Address Books
Getting Icedove and Owncloud to cooperate wasn’t that easy as expected (and as it should be!). First Problem, there is no way to enter a remote location for an address book (except LDAP) or calendar server. To ‘fix’ this one you need the Inverse SOGo Connector. The available software of the Debian repository does not include this frontend (just a sogo server and common files, as far as I can see) which helps to connect collaborative applications. So just download it from the website and install it. This time, the Thunderbird plugin works fine with Icedove. The SOGo Connector adds the entry Remote Address Book in the address book’s menu which can be found in File->New in your address book view. In the appearing wizard you can enter your owncloud address book link and your done.
Same thing for the calendar. Create a new calendar, choose On the Network and CalDAV and enter your proper owncloud link. When the sync seems not to work, and you get a message on startup (vie console) saying the calendar location seems to be a CalDAV collection and therefore is in the wrong format, you have entered the wrong link. If this is the case, log into your owncloud account, choose calendar and spot the button to get the personal link. This should include your login as an directory level in the URL. Use this link for your calendar location in Icedove.

reusing time machine backup disk for new (ly installed) mac

March 25th, 2014 4 comments

The migration assistant only offers the option to inherit an old time machine backup during the os installation. I had to wipe and reinstall my macbook 4 weeks ago (tinkered to much with os-dependent services ^^) and now wanted to incorporate my old time machine backups so that I have access to old file as i started with a clean mac not using the migration stuff (as this would most probably have recreated some of the issues i wanted to evade in the first place). Turns out the time machine has a command line interface tmutil that make this task very easy:

sudo tmutil inheritbackup /Volumes/BACKUPDISK/Backups.backupdb/OLDMACHINENAME

Categories: software Tags: