Re: file io script example

[James Dickens <jamesd dot wi at gmail dot com>]

On 07 Sep 2005 21:44:07 -0400, Frank Ch. Eigler <fche@redhat.com> wrote:

snipped
> 
> Will what be the case?  Requiring guru mode for end-user scripts that
> use %{ %}?  Probably.  If such helper functions turn out to be widely
> needed and standardizable, they could be placed within a tapset .stp
> file, thus implicitly gaining guru-mode treatment.
> 

My point was, if i was in a prodution environment, i think it would be
a good thing to forbid guru mode for scripts that monitor the system.
So if you have to use guru mode to get the content of basic structures
there isn't much point to systemtap as a production ready tool.

> > or will systemtap be able to support C contructs like struct and
> > typedef in the future? if this is not the case it sounds terribly
> > broken.
> 
> I don't expect to see C type expressions in the main script language.
> I expect a limited class of C-style pointer expressions to be parsed
> and evaluated against the debugging information ($ptr->field->field).
> With experience, we may need to expand that facility somewhat to cover
> other cases, like struct "downcasting" used in various places.  I
> don't know what the far future will hold, except that "terrible
> brokenness" is unlikely to be acceptable.
> 
Shouldn't systemtap be able to handle all of the standard include
files in /usr/include and the includes in a 2.6.x kernel so users can
monitor the system? dtrace can use cpp to preprocess the include files
reducing some of the wor.  Seems pretty standard if you are want to
access structures in userland and kernel space.

James Dickens