Two years passed since I wrote an article here. There are so many other projects… Well, finally I’m writing articles for a security company where I’m actually employed as pentester. So here is the 1st one:
When using rsync you may encounter the problem that it sometimes stops in the middle of a transfer with no visible reason.
If you ask Google you will find out that also others have this problem occasionally. Unfortunately, the reason and the solution is hidden and hard to find within these articles.
I neither could find the actual reason but it is definitely a matter of the destination file(s) where to you sync the data.
The solution is to delete the file (or even the whole directory) where rsync stops. Then restart rsync and it will work like a charm!
This article describes how to monitor network traffic running the Android AVD Emulator on Linux. Continue reading
However, recently I created my first Facebook event. Afterwards I found out that the event is private by default if you don’t change any predefined settings. It means that actually nobody can see your event except you explicitly invite them.
So, did they really implement privacy by default? Or is it just an accident?
And furthermore, there is no option to change the event’s visibility once it is created. The only way to make it public is to recreate the event.
This is a very interesting behavior because in contrast there are a lot of other settings in Facebook which I would expect them to be private, but they are not.
Actually, I don’t believe in accidents of a multi-billion dollar company…
error: unknown filesystem. Entering rescue mode... grub rescue>
You booted from an external drive and installed Linux to the SSD disk and everything seems to work fine. But after shutting down the system you suddenly cannot boot anymore.
Googling for it brings several similar issues but it’s hard to find a solution between all those people’s postings looking for help. Continue reading
Pieter had an unexpected severe problem with his auto pilot in the middle of the southern Indian ocean, 4500 kilometers away from the next harbor. The autopilot keeps the boat on track. Obviously, the autopilot is a very important piece because the skippers have to go to sleep during 10 weeks alone on a boat.
In a live interview in the Vendee Globe web TV live edition on the 15th of December 2016 he said:
“[…] …these companies that deliver this crap… […] …they just keep on pluging in new items and new software and new this and new that and it’s all nonsense. I mean, we don’t need all that stuff. We just need an straight up and down autopilot. It’s all this electronic designer geeks that really ruin a system. It’s so unstable! You don’t find all this crap on a fishing boat or a tug boat. It’s all way too advanced stuff that is designed behind a screen and a board and has nothing to do with seamanship or a seaworthiness.”
These are true words spoken by a man whose life depends on software. In my opinion this can be applied not just to companies writing software for boat electronics.
Here’s the original video. The interview starts at about 3:55.
Short answer: you can’t but yes, you can!
This is an endlessly recurring question in many groups on the Internet. Today (2016/01/14) Google has 171 Million hits. This article answers the question and sheds some light on arrays in C. In the second part below I’ll discuss two-dimensional arrays as well.
IMO, arrays are the most misunderstood language construction of C, even more than pointers. Everybody knows that these mysterious pointers are somehow dangerous, thus people (beginners) tend to either avoid, or really try to understand them.
But arrays are something that every beginner quickly understands (in any language). But in C, arrays are actually hidden pointers which makes them even more dangerous than pointers.
Some time ago I wrote this article about using integer operations to calculate fractal images. Currently, I’m giving a course which prepares for malware analysis. Among other things we deal a lot with Intel assembler and how compilers create and optimize code.
The full code of everything discussed below (and also of the article referred to above) is found on Github at github.com/rahra/intfract.
One of the exercises was to write the integer version of the iteration function manually in assembler. Here is the original version in C: Continue reading