FreeTDS Development Group

["Brian Bruns" <camber AT ais.org>]

I guess I don't have a good grasp of the problem either.  Someone want to
put a small test case together that demonstrates it?

Brian

> My grasp of what's really going on here is tenuous, but I've got the
> feeling that my change may not be the proper one, it just happens to fix
> my problem.
> 
> As a side note, while mucking around with ODBC (using the 2002-04-06
> version of FreeTDS) I found that TEXT fields returned with one *extra*
> character at the end!  But I can't test the latest version of code, so
> I'm not ready to make a claim about that yet.
> 
> I don't understand the deeper issues being discussed, but how about this
> instead?
> 
>          cplen =3D srclen > destlen ? (destlen-1) : srclen;
>          memcpy(dest, src, cplen);
>          dest[cplen] =3D '\0';
>          return cplen;
> 
> This is at least safe from buffer overruns, fixes my problem, and seems
> right, regardless of the deeper issues (which may still need to be
> addressed, but not by my small brain).  If we assume that srclen is the
> number of data characters without a terminator, this ought to be right,
> I think.  ?
> 
> Eric
> 
> 
> > -----Original Message-----
> > From: Brian Bruns [mailto:camber AT ais.org]
> > Sent: Tuesday, July 09, 2002 8:47 AM
> > To: TDS Development Group
> > Subject: [freetds] RE: Losing last character of TEXT fields
> >=20
> > It think the root cause may be deeper.  Why is a short destlen being
> asked
> > for?  This may have something to do with the return value of
> dbdatlen() or
> > similar calls... ie the application code may be:
> >=20
> > mylen =3D dbdatlen(dbproc, colnum);
> > mybuf =3D malloc(mylen);
> > dbconvert(dbproc,..., mybuf, mylen);
> >=20
> > So by fixing dbdatlen() or whichever it turns out to be, we may get an
> > extra char *and* no buffer problem.
> >=20
> > Brian
> >=20
> > > I think you're right, Frediano; the code is still broken.
> > >
> > > We shouldn't null-terminate unless destlen is -1.  If the
> destination
> > buffer
> > > is too small, we should call the error handler and return -1.  So
> say
> > the
> > > docs.  Eric?
> > >
> > > --jkl
> >=20
> > ---
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