nolibc-example

Spent an evening playing around with writing a small 64-bit Linux C program that does not use a standard C library (libc). Shows how to set up _start to provide main() with argc, argv and argp.

I'm sure I didn't get everything in the init just right (like the stack red-zone), but it seems to work [on my system].

Example output

The test program prints the obligatory "Hello, World!" and then the first character of all the args and the first four characters of all the envvars, demonstrating these have been passed correctly from the loader. The length of the hello write(2) is returned to the shell.

$ env -i AA=1 BB=2 CC=3 ./nolibc-example a b c ; echo ">>status=$?"
Hello, World!
argv:
a
b
c
envp:
AA=1
BB=2
CC=3
>>status=14