Hi all, I've been passively following seL4 for several years. I've been
reading the documentation, tutorials, watching YouTube videos.
The concepts behind capabilities and other types of kernel objects are
starting to sink in but there's one piece of understanding that's eluding
me.
If I just haven't stumbled across it yet in the documentation, then
pointing me in the right direction would be greatly appreciated.
Given:
* An ethernet driver named "e1000" and 2 devices "eth0" and "eth1"
controlled by that driver.
* A "tcp" service that would implement that network protocol.
* A higher level service named "network" that implemented some kind of
networking abstraction for us.
How would:
1) the "network" service advertise its services as available via IPC?
2) an application locate this "network" service to be able to IPC with it?
I assume the mechanisms here would also apply to interactions between
services as well. I picked the "network" service in this example only
because it would be the boundary between application and OS services.
I'm guessing that maybe this is purely an OS design decision and not the
purvue of the kernel itself. Perhaps init could launch a "service manager"
process that would be responsible for starting up services and drivers for
example and this "service manager" could provide an IPC endpoint back to
init (or whomever) to use for IPC discovery. Then, whenever a new process
is started, it is provided with the IPC discovery endpoint information that
it is to inherit.
If my assumptions are correct or close, or even dead wrong, would someone
be willing to share some pseudo-code on what this could/should look like in
seL4?
If a central service manager is needed to glue the core OS together, does
it represent a single point of failure and how would the OS recover if it
crashes and loses it's database of available services without having to
rebuild and restart all drivers and services? (I'm not saying that's a bad
thing, just trying to wrap my head around how this particular part of seL4
works)
Thanks,
Royce Mitchell, IT Consultant
ITAS Solutions
royce3(a)itas-solutions.com
There are three hard problems in computer science: naming things, and
off-by-one errors.
