Simple dd-like image writer with additional security checks.

dd if=/dev/zero of=./disk.img bs=1M count=1024
losetup -fP ./disk.img
losetup -a
losedup -d /dev/loop0

See:
    https://github.com/landley/toybox/blob/master/toys/posix/dd.c
    https://github.com/illiliti/libudev-zero
    https://github.com/LoupVaillant/Monocypher