On 9/3/21 11:54 AM, Mike Kaganski wrote:
Hi!
I understand that the question is less than ideal, and I'm sorry for
that.
I'm trying to debug a very strange bug in Firebird built into
LibreOffice (embedded DB functionality). A specific ODB (a package
that contains a FB database) crashes executing a query 'SELECT
DISTINCT "ТипВорот" FROM "ВОРОТА"', with the field used in the query
is a Varchar; and I was able to debug up to the point at
Sort::diddleKey, where for some reason the following line:
const USHORT fill = n - sizeof(USHORT) - vlen;
has n less than (sizeof(USHORT) + vlen), resulting in a large
resulting value, which then in the following line:
memset(fill_pos, fill_char, fill);
results in access violation.
Additionally, the wrong value of vlen seems to be set in the same
function at
((vary*) p)->vary_length = *((USHORT*) (record +
key->skd_vary_offset));
but I fail to follow the logic why that happens.
I tried to extract the database, and use isql tool to perform the same
query interactively - and that works fine. I also have cloned and
built FB from its github repo in DEBUG mode, in the hope that it could
allow me to catch the condition in the debugger - bit in it, the
problem is never met.
I actually suspect that our integration might do something wrong
initializing the engine, but I am very inexperienced in FB
development, and can't easily see what's wrong there.
I doubt much that wrong init can cause such kind of errors. But I see
russian letters here, which are 2 bytes in utf8 but 1 - in cp1251. Could
it be related with differnt connection charset or something else like
that? In what charset does LO talk to FB?
LibreOffice project uses FB 3. I am debugging on Windows using VS. I
would be glad for any advise where to look/put a breakpoint/etc to
nail down the project. Possibly my poor description could still make
some dev here to tell "Of course, it's Foo; how could he not know that
basic thing!" - that would be super-cool :)
Always useful to add stack trace (preferanly wih line numbers). DB
metadata is also welcome.
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