Re: SIGSEGV, FPE fix in pg_controldata

Hi Ian,

On Thu, Dec 12, 2024 at 12:23 PM Ilyasov Ian <ianilyasov(at)outlook(dot)com> wrote:
> SIGSEGV was caused by two places in pg_controldata.c where there
> is a work with localtime(&time_tmp));. So I added a check for not NULL.
>
> ....
>
> Where casting second operand in % (XLogSegmentsPerXLogId(wal_segsz_bytes)) to unsigned seems enough. Would be glad to hear your thoughts.

Thank you for catching this. I think catching invalid timestamps is
good except we could use already existing string indicating this and
don't bother translators. Also, I don't think we should change
segment size to uint32 as it's already defined as int in awfully a lot
of places. Additionally WalSegMaxSize is clearly within the 32-bit
integer max value. So, I think we can just adjust the check before
XLByteToSeg(). What do you think?

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Regards,
Alexander Korotkov
Supabase