Any hand-on exercise to understand how a program is loaded into memory and get executed

Question

I am curious about the things happend before main() is called , such like load the executable into memory , dynamic load of shared library. Do you have any suggestions how to understand these things by a hand-on exercise?

The tools amd things I know of ,and using now, includes:

• strace
• disassemble
• readelf
• /proc/pid/map

NOTES: I know the great book linkers and loaders, but hands-on exercise may teach me better than reading the book.

Answer 1

• The ld.so man page documents several environment variables that may be set to either tweak the dynamic linking process or provide additional details.

e.g.

LD_DEBUG=all cat </dev/null

• You can easily obtain the source code for each and every piece involved - Linux kernel, dynamic linker, C library, startup code (crt0.o or similar). You could start by studying the code and making experimental modifications.