Browsed by
Month: April 2018

LD_PRELOAD and stealing function calls

LD_PRELOAD and stealing function calls

There is a clever little trick that one can use for a variety of purposes on Linux. It involves overriding or hijacking function calls. It’s called LD_PRELOAD.

Lets say you create a file called unrandom.c that includes an implementation of the rand() function. It matches the function rand() in standard C.

unrandom.c:
1
2
3
int rand(){
    return 42; //the most random number in the universe
}

We’ll compile it into a shared library.

gcc -shared -fPIC unrandom.c -o unrandom.so

Now… just run a program (my_program) that uses random numbers like this, and you’ll find that the rand function only generates 42.

LD_PRELOAD=$PWD/unrandom.so ./my_program

This trick can be used in a variety of ways. A good write-up can be found here, and is worth a read:

Dynamic linker tricks: Using LD_PRELOAD to cheat, inject features and investigate programs

Projection Mapped Data Sculptures

Projection Mapped Data Sculptures

Media artist Refik Anadol’s work Melting Memories combines data and light projections  to visibly demonstrate how the brain recalls memories. The installation was created with a custom 16 x 20 foot LED media wall and CNC milled rigid foam, and was shown earlier in 2018 at Pilevneli Galleryin Istanbul.

She’s also done a lot of other interesting stuff. Check out her website.

 

Vector graphics are back!

Vector graphics are back!

Remember the arcade game Asteroids or the vector-based Star Wars arcade game? How about the vector-graphics based Vectrix game console?

Say hello to LaserOS. It that allows you build really cool, high quality vector graphics dreams – on real laser projectors. You can build visual laser shows, visualizations, control and create musical compositions, and play some great old games.

Here’s a developer that re-created Asteroids with a high-quality laser system (bonus points for talking about the difficulty of the traveling salesman problem):

Here’s one reviewer giving LaserOS a go on his laser projector:

What all the markings on ocean-faring ships mean

What all the markings on ocean-faring ships mean

Tugboat crews easily read a vessel’s size, shape, function, and features, while deciphering at a glance the mysterious numbers, letters, and symbols on a ship’s hull. To non-mariners, the markings look like hieroglyphs.

Hakai magazine on coastal science published a really cool article that helps you decode all the interesting markings, paint schemes, and functions of the interesting and strange things you see on big ocean-going vessles. I had no idea there was so much interesting information – and that paint schemes are far, FAR more complicated than marking water lines. Give it a read.

plimsoll lines on the side of a ship

How much info does Facebook have on you? It’s creepier than you know.

How much info does Facebook have on you? It’s creepier than you know.

Thrillist did a great article on all the ways your information, every detail about every place you’ve been and what events you’ve gone too, every photo you’ve liked or commented on, and all your personal information – even if it’s been listed as ‘private’.

My favorite is stalkscan. Pretty terrifying fun.

Give it a read and realize Google, Apple, and all your other favorite companies and online sites collect all this information and more – using it for marketing, selling it to other companies, and eventually all of it gets leaked when the inevitable hack or employee steals it.

The wise person

The wise person

The greater our knowledge increases,
the greater our ignorance unfolds.
-John F Kennedy

So, by this measure, the greatest and most dangerous fool is the one that posits they are intelligent. Even worse, when they do not have the wisdom to admit they are probably ignorant on the subject or could be wrong. In other words, just about 99% of all conversations on social media.

So lets all do each other a favor. Let us agree that spending 30-60 minutes a day reading articles on a topic from your favorite biased news sources does not make you ‘an expert’ or even ‘well informed’. Let us also take a step back from so self-assuredly believing and asserting everything we think.

Better yet, how about we love and respect each other – discussing our differences while respecting the person. Maybe, while we’re at it, we’ll all learn how not to be controlled by our outrage driven social agenda pushers.