This article is definitely not intended to teach you how to optimize your programs. That is, unless your usual programs are small enough to embed inside object file headers with the opcodes overlapping header field values.
It's a clever hack that teaches you about how ELF works by forcing you to think carefully about every single byte in a customized ELF executable.
I work frequently with object file formats (especially ELF) and write tools which manipulate executables and libraries and when I first read this article about 5 years ago I learned more about ELF than from any other source.
Comments
This article is definitely not intended to teach you how to optimize your programs. That is, unless your usual programs are small enough to embed inside object file headers with the opcodes overlapping header field values.
It's a clever hack that teaches you about how ELF works by forcing you to think carefully about every single byte in a customized ELF executable.
I work frequently with object file formats (especially ELF) and write tools which manipulate executables and libraries and when I first read this article about 5 years ago I learned more about ELF than from any other source.
Highly recommended!
My usual programs are. In fact, you might have one of them on your computer right now... unless you've run a scan recently. ;)