ELF file structure in FreeBSD & Linux

Question

In PE (for windows) it is possible to read the headers/sections of that structure by #include<windows.h> and can use the struct PIMAGE_DOS_HEADER to read the dos header in any PE file, for example.

How can i do that for ELF header in FreeBSD/Linux? What kind of preprocessor need to be added at the head of the C/C++ code? and Is there any difference between FreeBSD and Linux in term of the structure of ELF?

Answer 1

I can't vouch for FreeBSD, but on Linux there are a lot of details in the elf(5) manpage:

NAME
   elf - format of Executable and Linking Format (ELF) files

SYNOPSIS
   #include <elf.h>

DESCRIPTION
   The header file <elf.h> defines the format of ELF executable
   binary files.  Amongst these files are normal executable
   files, relocatable object files, core files and shared
   libraries.
...

When I needed to understand ELF, I found nothing more useful than the MuppetLabs Tiny Executable walk-through. I'm sure many of the techniques are out-of-date (and were never a good idea), but they explained things very well.

Answer 2

Here are some pointers which should help you out:

• Oracle article LibElf and GElf - A Library to Manipulate ELf Files

• GElf

• Libelf homepage

Answer 3

Look at the sources of readelf. Or just google. For example, this http://www.scribd.com/doc/7027807/ELF-Format looks promising.

If you just want existing code, try http://www.linux.com/learn/docs/man/2838-elf5.

Answer 4

You're looking for libelf.