Subject: Re: [linux-audio-dev] sound/gui interaction
From: David Olofson (david_AT_gardena.net)
Date: Fri Jul 21 2000 - 18:10:03 EEST
On Fri, 21 Jul 2000, Maarten de Boer wrote:
> On Thu, 20 Jul 2000, douglas_AT_roar.music.columbia.edu wrote:
> > thanks! now i need to figure out about the running as root problem...
>
> Some obvious things:
>
> I understand your concern, but I think it's good that running
> highest priority applications is restricted to root.
Yes, because, most importantly, a SCHED_FIFO or SCHED_RR thread may
freeze the entire user space whenever it feels like it.
However, this can be fixed with a watchdog, either in kernel space,
or in a daemon. Of course, for this to be *safe*, one has to make
sure the watchdog cannot be disabled by any RT application.
> Besides, when you give the application proper permissions during
> installation, the user is not required to become root to run the
> application.
Yep, but...
> If you are really concerned about security, you can have your
> processing stuff running in a seperate application, and have
> your gui application running as normal user. (like jMax for
> example)
...if the application runs plugins (in particular, closed source
plugins), you're in trouble. Basically, Win9x + Internet Explorer
reinvented. (For those who luckily escaped it; web pages could make
it download and execute binary applets without the user even seeing
what's going on. And Win9x doesn't have any kernel level
security...)
This *HAS* to be fixed, and at kernel level AFAIK.
> But than ofcourse you loose the threading, and have
> to think of some communication between gui and processing.
What's the big deal? This is pretty much required anyway... (Shared
memory still works, of course, if you want a simple "shared structs"
kind of interface.)
//David
.- M u C o S --------------------------------. .- David Olofson ------.
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