FreeTDS Development Group

["Mark J. Lilback" <mark AT lilback.com>]

Ok, I'm getting a weird bug that I'm not positive about. This is all 
using TDS 4.2 on a big endian platform. The source is a bit old, but 
I think the same fundamental flaw is there in the current code.

I see the problem when trying to connect to a host with 34 
characters. At some point during tds_send_login, tds->s gets set to 
zero, which screws up the connection. There are multiple lines in 
there that seem to have a 30 character limit, so that looks like it 
should be the problem. (There is no problem using the ip address.)

Now what is strange is that I'm seeing the problem happen on the 
following line on the tds_send_login function in login.c.
   rc|=tds_put_string(tds,(unsigned char*)login->language,30);  /* language */

In this case, login->language is an empty string.

Stepping through the debugger, I get to the following call:
tds_put_buf(tds, "", 30, 0);

Here's the appropriate code from write.c:

int tds_put_buf(TDSSOCKET *tds, unsigned char *buf, int dsize, int ssize)
{
char *tempbuf;
int  cpsize;

        tempbuf = (char *) malloc(dsize+1);
        memset(tempbuf,'\0',dsize);
        cpsize = ssize > dsize ? dsize : ssize;
        memcpy(tempbuf,buf, cpsize);
        tds_put_n(tds,(unsigned char*)tempbuf,dsize);
        free(tempbuf);
        return tds_put_byte(tds,cpsize);
}

I'm thinking that if ssize <= 0, then it should just return success 
since there is no need to do anything. Or at a minimum, don't try the 
memcpy with a cpsize of zero (this could be some kind of bug in 
memcpy, I'm not sure). The memcpy line is where I'm seeing tds->s get 
cleared.

Like I said, this seems like a really strange place for this problem 
to be resolved at. However, I'm thinking this is a bug in tds_put_buf 
that should get fixed.

Opinions?

--
__________________________________________________________________________
                                  "They that can give up essential liberty
Mark J. Lilback                    to obtain a little temporary safety
<mark AT lilback.com>                 deserve neither liberty or safety."
http://www.lilback.com/                               -- Benjamin Franklin