--- Holger Waechtler <[EMAIL PROTECTED]> wrote:
Why does VT switch have to be in the kernel? I can have multiple xterms
logged
in as different users without kernel support. Why can't VT switching be implemented as if I was switching between multiple fullscreen xterms? I
guess I
don't see why there is a difference between multiple xterms and VT's. I can
use
su to set the xterm to any account.
what if you want to create a 'fresh&clean' console using the SAK key or if your primary terminal is not responsive anymore?
You need to be able to create a new terminal without any help of the currently active console and you need to be able to restart the graphics helper library/server/whatever at any time without killing your running applications on other 'VTs'.
In this model SAK is implemented in the kernel by the system console. Hitting SAK will always work even if the terminal is not responsive (unless the kernel is dead). SAK will whack all apps on the user console, reload the graphics libs, and get you a fresh shell. In this model it is not possible to restart the graphics lib on one console without restarting all of the virtual consoles since they are all sharing the same process.
This seems secure to me. Whacking everything with SAK and reloading the graphics libraries completely stops any attack that may try to load code into the graphics card. I wouldn't be surprised if you could write a pixel shader program that emulates a login screen.
It may be possible to build this to suspend the apps instead of whacking them. Then you could reattached them if needed. If not reattached in a few minutes they would die.
hmmm, it's not clear to me how this concept would allow real multiple user logins at the same time like it is common -- you can rum multiple X11 instances on multiple VTs and every new user is able to hit SAK without killing other user's applications.
Holger
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