development – Can I run my own app using operating system of cameras?

I am new in this domain, so i hope it is the right place for my question.

I know that Canon and Sony has operating systems such as DRYOS and BusyBox 1.4.2 (Linux Kernel).

I am wondering, if I can develop my own application and run it into these operating system?

Let’s say, the app simply generate a random string, when I take a photo.