mirror of
https://github.com/20kdc/OC-KittenOS.git
synced 2024-11-23 19:08:05 +11:00
250 lines
6.1 KiB
Plaintext
250 lines
6.1 KiB
Plaintext
Welcome to the documentation for your
|
|
KittenOS NEO system.
|
|
|
|
These documents are written to a 37-
|
|
column standard, in order to match
|
|
the Neolithic text editor.
|
|
|
|
If editing them, please set a right
|
|
margin of 37, or an equivalent,
|
|
in order to ensure that the
|
|
documents do not require horizontal
|
|
scroll in order to read.
|
|
|
|
This documentation is aimed at those
|
|
who wish to develop things for the
|
|
KittenOS NEO system.
|
|
|
|
Due to the size of the system, it is
|
|
divided into several sections,
|
|
each section being a file.
|
|
|
|
This section will cover an overview
|
|
of the KittenOS NEO system.
|
|
|
|
It is an abstract overview, but one
|
|
that will give you a framework in
|
|
which the components make sense,
|
|
should you simply skip to them.
|
|
|
|
The KittenOS NEO system is divided
|
|
into three things - the kernel,
|
|
libraries, and the processes.
|
|
|
|
The kernel is always loaded at all
|
|
times, and is the root of all system
|
|
activity.
|
|
|
|
The libraries are essentially Lua
|
|
values that are kept in memory by a
|
|
weak-valued table.
|
|
|
|
This allows them to be reused,
|
|
and memory saved, if possible,
|
|
while also allowing unloading.
|
|
|
|
This is a critical memory management
|
|
technique in KittenOS NEO, as it
|
|
allows certain libraries to be
|
|
loaded only when in active use.
|
|
|
|
(This also means libraries can have
|
|
security side-effects, but they
|
|
always can in any system, arguably,
|
|
and it's worth it for the memory.
|
|
Notably, library values get
|
|
wrapMeta'd automatically since R2,
|
|
in order to reduce NEO-specific
|
|
code.)
|
|
|
|
The processes are applications and
|
|
services, that communicate with the
|
|
kernel via the NEO Kernel API, and
|
|
that communicate with others via
|
|
Lua values and tables shared between
|
|
the processes, that also constitute
|
|
a form of API.
|
|
|
|
These APIs are shared and retrieved
|
|
via Accesses - anything that causes
|
|
a permissions check is an Access.
|
|
|
|
Accesses are easy to replace in the
|
|
system, should you wish to heavily
|
|
customize the system in some way.
|
|
|
|
The ability to receive given events,
|
|
is also an Access, though all "k."
|
|
events are always accessible for
|
|
simplicity reasons.
|
|
|
|
"All components are replacable, as
|
|
long as you implement it correctly."
|
|
|
|
Regarding the KittenOS NEO system
|
|
that you are now possibly running,
|
|
it likely has 3 critical services.
|
|
|
|
I refer to these as the Trinity, just
|
|
because it seemed to fit.
|
|
|
|
The following list notes which APIs
|
|
they provide and require, but only
|
|
from those in the "x." space.
|
|
|
|
Anything else is an implementation
|
|
detail, subject to change - indeed,
|
|
these are only listed for the sake
|
|
of those who need to find code for
|
|
a given API.
|
|
|
|
-------------------------------------
|
|
|
|
Glacier: sys-glacier
|
|
* formerly sys-donkonit
|
|
Shell-independent parts of NEO, such
|
|
as screen management and settings,
|
|
and the "saving throw" recovery
|
|
mechanism.
|
|
|
|
Provides x.neo.sys.manage
|
|
x.neo.sys.screens
|
|
x.neo.pub.globals
|
|
|
|
Everest: sys-everest
|
|
This is the default shell.
|
|
|
|
Provides x.neo.sys.session
|
|
x.neo.pub.window
|
|
|
|
Requires x.neo.sys.screens
|
|
Prefers x.neo.sys.manage
|
|
|
|
Icecap: sys-icecap
|
|
Shell-dependent component that
|
|
gains k.root and uses Everest
|
|
to implement the security policy.
|
|
|
|
Provides x.neo.pub.base
|
|
Requires x.neo.sys.manage
|
|
Prefers x.neo.pub.window
|
|
|
|
-------------------------------------
|
|
|
|
The bootup process, meanwhile, is
|
|
rather simple.
|
|
|
|
The kernel first designates the
|
|
primaryDisk based on the boot disk,
|
|
via the "deprecated" computer API
|
|
that has no replacement and is thus
|
|
nowhere near safe to remove.
|
|
|
|
The primaryDisk is *the*
|
|
KittenOS NEO system disk - it holds
|
|
the system, in full.
|
|
|
|
Inelegance here falls to the greater
|
|
power of practicality, as a VFS is
|
|
an unnecessary component here.
|
|
|
|
After moving its many globals into
|
|
place, it then immediately loads and
|
|
runs sys-init.
|
|
|
|
sys-init's job is to firstly display
|
|
the KittenOS NEO boot screen -
|
|
this is where it got its original
|
|
name from, s-bristol (see: Plymouth)
|
|
|
|
It chooses the screen / GPU based on
|
|
the best combination it can find.
|
|
|
|
The screen that it displays on is
|
|
then noted as the primary screen.
|
|
|
|
During this boot screen, it firstly
|
|
starts Glacier, which is always a
|
|
necessary component for sys-init to
|
|
operate correctly.
|
|
|
|
It then starts all services that have
|
|
"run." entries set to "yes".
|
|
|
|
By default this means sys-icecap.
|
|
|
|
Note that sys- entries occur first.
|
|
|
|
This allows a security policy to be
|
|
installed, typically by sys-icecap,
|
|
that allows non-sys- parts to
|
|
perform useful operations.
|
|
|
|
Finally, screen control is passed to
|
|
Glacier, and sys-init resets the
|
|
screens to their login-screen-state.
|
|
|
|
If the settings daemon is not around
|
|
by this point, sys-init fails-safe
|
|
and allows login & safe-mode.
|
|
|
|
(If you happen to be able to cause a
|
|
sys-glacier error, during early boot
|
|
in a way that does not require any
|
|
permissions with other ways of
|
|
creating havoc, then, this may be a
|
|
flaw in the system security model.
|
|
The risk is considered worth the
|
|
ability to theoretically use the
|
|
system.)
|
|
|
|
If the setting "sys-init.nologin" is
|
|
set to "yes", then the login screen
|
|
is skipped.
|
|
|
|
If the password is not empty, then
|
|
a password prompt is used.
|
|
|
|
If Lua 5.2 is in use, the usual set
|
|
of instructions are replaced with a
|
|
warning to use Lua 5.3.
|
|
|
|
After the login screen finishes,
|
|
sys-init disclaims the primary
|
|
screen, and runs the shell, dictated
|
|
by the setting "sys-init.shell" -
|
|
if settings are not available, then
|
|
sys-everest is used as a guess.
|
|
|
|
Up to 5 seconds later, sys-init
|
|
confirms that "x.neo.sys.session" is
|
|
an existing API, and thus a shell is
|
|
currently running.
|
|
|
|
If this does not occur in time,
|
|
then sys-init provides the:
|
|
"That wasn't a shell. Try Safe Mode."
|
|
message, and causes a reboot.
|
|
|
|
If it does, then sys-init finally
|
|
exits, with the "Trinity" in place,
|
|
and all screens automatically
|
|
disclaimed by sys-init's quit.
|
|
|
|
(NOTE: If your particularly beady
|
|
service happens to get ahold of a
|
|
screen during startup, then that
|
|
screen is of course unaffected,
|
|
unless your service dies. This is of
|
|
course intentional in case you want
|
|
a service to control a screen.)
|
|
|
|
This should summarize the system.
|
|
Good luck. - 20kdc
|
|
|
|
-- This is released into
|
|
the public domain.
|
|
-- No warranty is provided,
|
|
implied or otherwise.
|
|
|