vsyscalls [was Re: X15 alpha release: as fast as TUX but in user space (fwd)]

Pavel Machek
2001-05-11T07:05:05Z

Hi!

> > > PS: Hmm, how do you do timewarp for just one userland appliation with
> > > this installed?
> >
> > 1. What on earth for?
>
> Y2K testing was one previous example.
>
> > 2. How do you do it today, and why wouldn't that work?
>
> LD_PRELOAD and providing its still using a lib call it would. I dont see the
> original posters problem

LD_PRELOAD is not reliable: application may do syscall itself and find
out true time. But ptrace works currently and *is* reliable.

Problem is that vsyscalls ay take ability to use ptrace to fool apps away.
Pavel
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