[Toybox] [PATCH] readelf: Fix the section flags handling.

[enh]

On Thu, Nov 30, 2023 at 11:13 AM Rob Landley <rob at landley.net> wrote:
>
> On 11/29/23 18:47, Christopher Ferris wrote:
> > This patch fixes a bug in the handling of section flags.
> >
> > I added a new test elf file that shows the failures, but I'm not sure if you
> > would prefer some other way of doing the testing.
>
> Applied, but no I don't like the test.
>
> It currently fails on test_host:
>
> $ TEST_HOST=1 make test_readelf
> scripts/test.sh readelf
> PASS: readelf -h
> PASS: readelf -S
> FAIL: readelf -S flags
> echo -ne '' | readelf -SW
> /home/landley/toybox/toybox/tests/files/elf/ndk-elf-note-shflags | head -32
>
> Design-wise calling for an exact match for a very large block of english text is
> brittle. If spacing changes, the test breaks.

we already have the `NOSPACE=1` "ignore whitespace differences"
functionality in the readelf tests.

what's the actual difference in the failure you're seeing?

> If somebody rephrases "Number of
> section headers:" the test breaks. If the output entries are reordered
> (including adding more entries in the middle) the test breaks. Even if we fiddle
> to match debian's output, version skew will break us in a year or two...

_maybe_ but there are a lot of scripts out there to help keep them
(and us) honest. that's why i have tried to match the binutils output,
even when it's not great.

> It also doesn't specifically test what it fixes, and it's unclear what such a
> broad test is checking for. There's no way I could work out from the test that
> the patch adding it did:
>
> -      for (j=0; j<12; j++) if (s.flags&(1<<j)) *p++ = "WAXxMSILOTC"[j];
> +      for (j=0; j<12; j++) if (s.flags&(1<<j)) *p++ = "WAXxMSILOGTC"[j];
>
> Lemme think a bit. Possibly there's missing test infrastructure to make this
> sort of thing easier, some sort of automatic regex match maybe? (Like I added to
> txpect already in commit 8c7af93bde17 but that's an expect style
> call-and-response test infrastructure, not the "run this, what was the output"
> style most tests use...)
>
> Thanks,
>
> Rob
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