mirror of
https://github.com/20kdc/OC-KittenOS.git
synced 2024-11-16 23:48:05 +11:00
99 lines
2.5 KiB
Plaintext
99 lines
2.5 KiB
Plaintext
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.
|
|
|