Re: Can we do Java probing without invoking stapbm from staprun?

[David Smith <dsmith at redhat dot com>]

On Sat, Sep 23, 2017 at 6:51 AM, Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
> Hello.
>
> I'm using modified version of /usr/libexec/systemtap/stapbm in order to obtain more
> specific values of an object which cannot be obtained by implicit .toString() conversion.
> For example, passing $1.getRequestURI() instead of plain $1 when probing
> service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
> method of javax.servlet.http.HttpServlet class. There should be no problem for SystemTap
> side as long as number of arguments matches, for all values are passed to SystemTap side
> as string because of PR21020.
>
> Now, I'm trying to go further in order to make
>
>   "allow probing without giving permission to run staprun to the user who runs
>    Java application (e.g. tomcat)"
>
>   "automatically start probing as soon as target java process starts (or restarts)
>    as with normal userspace probing"
>
> possible by not invoking stapbm from staprun.
>
> Steps for demonstrating such usage is shown below. Can we legally support such usage?

I'm afraid I'm probably not the right person to comment on java
issues, but I do have a question. In that last question there, you
said "Can we legally support such usage?". Did you really mean
"legally" (as in a matter of law) or did you mean something else?

It also might help here if you went ahead and posted a patch of your
modified version of stapbm.

-- 
David Smith
Principal Software Engineer
Red Hat