RFR [XS]: 8224958: add os::dll_load calls to event log

[Thomas Stüfe]

On Wed, Jun 5, 2019 at 2:50 PM David Holmes <david.holmes at oracle.com> wrote:

> On 5/06/2019 7:06 pm, Baesken, Matthias wrote:
> > Hi Thomas , I removed  the error_report _ NULL check
> >
> > http://cr.openjdk.java.net/~mbaesken/webrevs/8224958.2/
>
> You missed one in src/hotspot/os/bsd/os_bsd.cpp
>
> +   if (error_report == NULL) {
> +     error_report = "dlerror returned no error description";
> +   }
> +   if (error_report && ebuf && ebuflen > 0) {
>
> >
> >    *   You moved lasterror() up to get a "fresh" error value before
> calling into event logging right? I needed a while to understand that. Okay.
> >
> > Yes this was my intention .
>
> Not sure I'd say "fresh" is the right description. An error has occurred
> and you want the error message for log statement. Its the same error
> message you'd get later as no other system call is being made. There's
> no difference to the how the code currently works, we just want the
> error text earlier for the log.
>

not quite :)

Matthias prints out the numerical errcode in his call to Events::log,
retrieved by GetLastError() some lines above. That has nothing to do with
lasterror and errbuf. lasterror() is used to fill errbuf. It too calls
GetLastError(), which makes it position dependend. Matthias added a new
call into the EventLog system, so he is careful and moves the call to
lasterror() up in case the EventLog system calls system APIs and overwrites
the error code.

..Thomas


>
> David
> -----
>
> >
> >
> >    *   It would be better to have a function which only does the text
> translation, using an error code we give it as parameter.
> >    *   Then we could have given it the errcode we already have. Would be
> good for a future improvement.
> >
> > There are not so many  os::lasterror   usages currently .  So I am not
> sure if it is really needed ,   let’s  do it in a separate CR  any way …
> >
> >
> >
> > Best regards, Matthias
> >
> >
> > From: Thomas Stüfe <thomas.stuefe at gmail.com>
> > Sent: Mittwoch, 5. Juni 2019 09:31
> > To: Baesken, Matthias <matthias.baesken at sap.com>
> > Cc: hotspot-dev at openjdk.java.net
> > Subject: Re: RFR [XS]: 8224958: add os::dll_load calls to event log
> >
> > Hi Matthias,
> >
> > looks good. Minor nit:
> >
> > +  if (error_report == NULL) {
> > +    error_report = "dlerror returned no error description";
> > +  }
> > +  if (error_report && ebuf && ebuflen > 0) {
> >
> > Since you ensure error_report is always set - with a default text, if
> needed - you do not need to check it for NULL afterwards.
> >
> > If you only fix this, I do not need a new webrev.
> >
> > ---
> >
> > Side note:
> >
> >
> http://cr.openjdk.java.net/~mbaesken/webrevs/8224958.1/src/hotspot/os/windows/os_windows.cpp.udiff.html
> >
> > You moved lasterror() up to get a "fresh" error value before calling
> into event logging right? I needed a while to understand that. Okay.
> >
> > This shows that lasterror() is actually not well designed. lasterror()
> does two things: 1) get the error code with GetLastError and 2) translate
> that numerical code to a text.
> >
> > It would be better to have a function which only does the text
> translation, using an error code we give it as parameter. Then we could
> have given it the errcode we already have. Would be good for a future
> improvement.
> > Cheers, Thomas
> >
> >
>