FreeTDS Development Group

["Thompson, William" <bill.d.thompson AT baml.com>]

Hi All,

I'm investigating an issue which is affecting some of my processes which use 
the db-library bcp API.
I'm getting an error back from SQL Server: "The incoming tabular data stream 
(TDS) protocol stream is incorrect. The stream ended unexpectedly."
After debugging it, It turns out we have an edge case involving some of the 
functions in src/tds/write.c

The functions tds_put_int8, tds_put_int and tds_put_smallint do not check 
that there is sufficient space in the packet buffer for their respective data 
types.
As a consequence, data gets dropped if it happens that one of these data 
types is being added to the packet buffer when the packet size is reached.

Having looked at the functions, I think I'm going to change these lines 
(which occur in all the functions):

        if (tds->out_pos >= tds->out_buf_max)
                tds_write_packet(tds, 0x0);

to be:

        if (tds->out_pos  + sizeof(TDS_INT) >= tds->out_buf_max)   /* or 
TDS_INT8 or TDS_SMALLINT */
                tds_write_packet(tds, 0x0);

If I do this there will be cases where the packet (although not a final 
packet) is smaller than the maximum size,
but I REALLY don't want to go anywhere near those TDS_PUT_UA* macros. :)
Incidentally, what is the idea behind this TDS_ADDITIONAL_SPACE macro and all 
those TDS_PUT macros? Life used to be much simpler (sigh), e.g.

<old code>
Int tds_put_smallint(TDSSOCKET * tds, TDS_SMALLINT si)
{
#if WORDS_BIGENDIAN
    if (tds->emul_little_endian) {
        tds_put_byte(tds, si & 0x000000FF);
        tds_put_byte(tds, (si & 0x0000FF00) >> 8);
        return 0;
    }
#endif
    return tds_put_n(tds, (const unsigned char *) &si, sizeof(TDS_SMALLINT));
}
<\old code>

Bill







----------------------------------------------------------------------
This message, and any attachments, is for the intended recipient(s) only, may 
contain information that is privileged, confidential and/or proprietary and 
subject to important terms and conditions available at 
http://www.bankofamerica.com/emaildisclaimer.   If you are not the intended 
recipient, please delete this message.