I think that's everything for day 13:
* O_CREAT support for openat
* Character and block devices, incl /dev/null, zero, full, and block devices and partitions
* Populate /dev with devices on boot
* Add idle task to scheduler
* New syscall: nanosleep
Next, in no particular order:
* Flesh out files a bit more (e.g. enforce O_RDONLY)
* Flesh out filesystem syscalls (mkdir, fstatat, etc)
* Signals & waitpid
* pipe(2), dup(2)
* Start writing a libc
* Port a shell