Android cheatsheet

Maximilian Hille / Wed, Jul 29, 2015

I googled the following things so often that I will be lazy and put them on my site for easier retrieval:

Android debug keystore fingerprint

keytool -list -v -keystore ~/.android/debug.keystore -alias androiddebugkey -storepass android -keypass android


Android emulator hardware acceleration

emulator -avd <avd_name> -qemu -m 512 -enable-kvm


Android emulator mock GPS location

adb emu geo fix 121.4961236714487 31.24010934431376


Update: GUI for ibutton

Maximilian Hille / Thu, Jun 4, 2015

The recently released Go application for controlling iButtons just got a small update: A GUI interface. It is very basic for now, but, as far as I know, the first graphical iButton interface for Linux.

I did not yet check if the App works from your Ubuntu Touch device, but since it should only depend on the installed kernel modules and working USB-to-go, I will need a physical device to actually test this. Android kernels usually do not carry the necessary drivers…

Building this has been a nice opportunity for me to learn a bit of the upcoming Ubuntu way of doing apps. The Ubuntu SDK uses Qt/QML as frontend language. QML is a specialized JavaScript’esque language for doing MVC. Qt has bindings ready in a lot of languages, but Go being part of the officially supported ones in the SDK (Go, Python, C++) could be a nice go-to app architecture in the future.

That said, the Ubuntu SDK is still at a very early stage. After years of doing Android, Ubuntu’s docs and the IDE (customized QtCreator) seem pretty rough.

You can find the project on GitHub, the license is (like the rest of go-netlink) GPL3+.

Go release: go-netlink

Maximilian Hille / Tue, May 5, 2015

To read Maxim iButton temperature sensors in Linux is not a big problem, but needs some work. There is a kernel module / driver for the USB reader adapter. This kernel module can be accessed from user space via a special file ‘rw’ or via a Netlink interface.

The ‘rw’ method is straight forward (with the technical docs from Maxim), but has some drawbacks: The file as it is created is only accessible for root and the location of this file is depending on the unique ID, distribution and maybe even the kernel version.

The Netlink method does not have these drawbacks, but in order to use the Netlink interface, you need to learn a bit about the Linux kernel.

After reading more kernel code that I wanted and learning about how to debug a running kernel (thanks for making Systemtap), I managed to talk to the iButton. You can grab the code at GitHub, it’s license is GPL3+.

The Go packages mirror the Netlink / Connector / One-Wire layer hierarchy within the kernel. Thus, the code can also be interesting for people trying to talk with other branches on those subsystems.

Note that the implementation is not very clean yet. I get some warnings like ALLCAPS for constants. I consider myself still a Go rookie ;-)

App release: Watch Later

Maximilian Hille / Tue, May 5, 2015

Do you also sometimes encounter YouTube links while browsing on the way? Chances are you have the same problem as me: the YouTube app would open and instantly start buffering, consuming precious amounts of mobile data volume.

Do not want to miss the video but watch it later with unlimited internet (eg. at home)? Look no further - I just released a small app called ‘Watch Later’. It registers on YouTube http URLs and can add the video to your YouTube account’s Watch Later list.

Available for free on Google Play

Feedback welcome on Reddit

The App is licensed under GPL, sources available on GitHub

The Second Cloud

Maximilian Hille / Wed, Oct 1, 2014

A lot of us fell victim to the sweet poison of cloud services – me included. Services I use on a daily basis include Google Drive, Google Maps, Github and Gmail, just to name a few. Those are comfortable programs. Running in your browser, everywhere, always up-to-date. No need for backups or any maintenance at all.

What is the price of all this?

You are not only accessing data on remote systems, but you can not know what code will run over there. This is actually worse than running proprietary software on your machine, since you lost even the most basic ways of analysing what’s happening.

Also, giving away the control over your data. Most services will tell you that the data is secure there, but do not believe them! They can access the data and will give access to whoever has enough power or money.

What now?

Everyone builds their own server? This is where a lot of still active services originate from. Mail and Websites can be run by yourself, but it certainly not possible for everyone.

The last months and the success of Bitcoin let me to believe that peer-to-peer based services can help. Bitmessage tries to replace Email. There are even more ambitious ones like MaidSafe which have no lesser goal than building an Internet replacement.

These ideas are not entirely new: Freenet is around for more than a decade now. Back in 2000 there were already visionaries who knew that we would have to defend freedom on the Internet.

The currently existing/developing services might not survive the test of time and acceptance, but there are already hundreds of projects, most of these sharing concepts and code. Thus, I am confident that we will be able to replace current cloud services one-by-one with more secure peer-to-peer based alternatives.

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