[DTrace-devel] [PATCH v2 20/20] Support probeprov, probemod, probefunc, probename built-in variables

[Kris Van Hees]

On Tue, Jun 08, 2021 at 11:34:06AM -0400, Kris Van Hees wrote:
> On Mon, Jun 07, 2021 at 06:57:46PM -0400, Eugene Loh wrote:

<< irrelevant portion omitted >>

> > I guess I already mentioned in my other email that I don't think the 
> > prefix should be written to the output buffer.  (The consumer not only 
> > tries to print the varint, but it also checks it for unprintable 
> > characters, leading to rather surprising variations in output.)  The 
> > other email proposes a patch, though I imagine you can cook one up just 
> > as easily.  Main thing is tests to catch this sort of thing.  I'd be 
> > interested in seeing this patch again after such fixes.
> 
> I think your conclusion is wrong.  There is nothing wrong with including the
> prefix in the output buffer, and in fact it can be very beneficial and may be
> used in the future to reduce wasted space in output records and a variety of
> other improvements based on having this information readily available.
> 
> The fact that the trace() action is nt behaving right is not necessarily a
> function of this code putting out the wrong data (length prefix included with
> the string data).  It seems more like a problem with trace() not being able
> to digest the data correctly.  And yes, trace() has not been updated to deal
> with strings - and that is an interesting issue that will need some attention
> and simply not make it into this patch series.
> 
> And yes, tests should catch this stuff and it shows that we still have some
> major holes in the test coverage.  This case is where there need to be more
> tests for the trace() action to cover all the cases we should support (and
> negative tests for things that should not be supported).

I'll be posting a patch in a moment that adds support to trace() for string
data.  This will also flip the actions/trace/tst.str.d test to PASS (from
XFAIL).  I'll check to see if other tests are now passing as well.

	Kris