Re: [PULL 07/21] cutils: Fix wraparound parsing in qemu_strtoui

[Michael Tokarev]

02.06.2023 01:02, Eric Blake пишет:
> While we were matching 32-bit strtol in qemu_strtoi, our use of a
> 64-bit parse was leaking through for some inaccurate answers in
> qemu_strtoui in comparison to a 32-bit strtoul (see the unit test for
> examples).  The comment for that function even described what we have
> to do for a correct parse, but didn't implement it correctly: since
> strtoull checks for overflow against the wrong values and then
> negates, we have to temporarily undo negation before checking for
> overflow against our desired value.
>
> Our int wrappers would be a lot easier to write if libc had a
> guaranteed 32-bit parser even on platforms with 64-bit long.
>
> Whether we parse C2x binary strings like "0b1000" is currently up to
> what libc does; our unit tests intentionally don't cover that at the
> moment, though.
>
> Fixes: 473a2a331e ("cutils: add qemu_strtoi & qemu_strtoui parsers for int/unsigned 
> int types", v2.12.0)
> Signed-off-by: Eric Blake <eblake@redhat.com>
> CC: qemu-stable@nongnu.org

Trying to pick this one up for -stable. The implementation changes are good.
But the testsuite changes are.. difficult.  The thing is that testsuite changes
(here and in the other -stable patch) applies on top of previous changes in
there (in the same series), which, in turn, requires other previous code changes
in the implementation to succeed.

For example, this patch changes test_qemu_strtoui_overflow() which was 
introduced
in previous patch "Test more integer corner cases" from this series and further
modified in "Test integral qemu_strto* value on failures" one.  Picking them 
result
in testsuite failing due to missing previous code changes.

I tried to drop just the testsuite changes, but the result is that the testsuite
fails with fixed code :)

It's quite fun situation actually, like it fails no matter what you do, one way
or another.

I'll try to find the most stright-forward way from here.  Good stuff.

Thanks,

/mjt