precompiled probing scenarios

[Frank Ch. Eigler]

Hi -

On Fri, Oct 06, 2006 at 03:33:19PM -0500, David Smith wrote:
> [...]
> Hmm.  Are we hashing the input script?  If so, how does this work with 
> probe wildcards?  For example, let's say I probe "kernel.function("*")". 
> We compile and cache this module.  I then plug in a bunch of 
> additional hardware, which causes several extra modules to be loaded.  I 
> then run stap again with the exact same input script.  [...]

kernel.function("*") should match exactly what was there before.
Probes on module("*").FOO would be redefined to mean something like
"all modules that we know at translation time that *might* exist, that
also happen to be *loaded* at run time.  This aspect of wildcard
expansion would thus take place at run time rather than translate
time.  It just so happens that the same module might probe a greater
or lesser number of modules on an actual system.  With that proviso,
a script-source-level hash still seems to work.

> Wow.  Supporting different kernel versions on the same arch/cpu is
> currently supported.  Doing different arch/cpu types is going to be
> difficult.  [...]

Yeah, I figure proper cross-architecture compilation would come later.


> [...]  Hmm.  Is this new staprun.auth variant a setuid program or
> does the user still need sudo privileges?

It could be setuid.


- FChE