OC-KittenOS/repository/docs/kn-intro

The KittenOS NEO Kernel,
 aka "init.lua", or as I like to call
 it, "KNOSKRNL", is what happens when
 someone tries to write a microkernel
 in Lua, and make it efficient.

Obviously, the result is not entirely
 what would be expected from a kernel
 at all, nevermind a microkernel.

In particular, it borrows an
 important concept, specifically fast
 yet secure IPC.

By which I of course mean that the
 IPC consists of programs giving Lua
 values to each other directly, and
 the kernel giving the programs some
 mechanisms to help secure this.

Not what you expected, I assume.

The "kn-" group of documents is about
 the KittenOS NEO kernel.

This is specifically ONLY about the
 kernel, and only about features the
 kernel provides directly.

As the kernel provides many things to
 everything under it, I believe this
 is of great use.

It's now time for the notes about the
 kernel side of the boot process.

Firstly, the startup of sys-init is
 unlike any other - specifically, it
 has a nil callerPid/callerPkg pair.

This is because no application ran a
 function to create the process - it
 was created by the kernel.

Secondly, here's what goes on in the
 kernel when an Access is registered,
 and when it's accessed:

1. The service requests access with
    an AID starting with "r.".
2. The security policy presumably
    accepts the registration.
3. A blank registration in the table
    "accesses" is made immediately.
   This registration always fails to
    be retrieved, but exists.
4. A function is returned to reset
    the registration.
5. The service calls the function,
    thus the registration is now
    completed.

6. The user-process requests access
    with an AID starting with "x.",
    everything after matching that
    in the "r." registration.
7. The security policy presumably
    accepts the use of that API.
8. The callback in the registration
    is called.
   Its first return value is sent
    back to the user-process.
   If it errors, then nil is given
    instead (the error is not sent).

Thirdly, the security policy is set
 by getting the kernel global table
 with "k.root", and then changing the
 global "securityPolicy".

Given this operation is only ever
 performed once in typical use, and
 having control over it is equivalent
 to instant root, it seems fitting
 that it is done this way.

(Making absolute power absolute is
 also why the kernel loves globals.)

Finally, the kernel prevents those
 processes that aren't "sys-" from
 calling "sys-" processes.

-- This is released into
 the public domain.
-- No warranty is provided,
 implied or otherwise.