[Iaxclient-devel] Re: Aha: The next IAX2 bug (PPC only, I guess)..

[Mark S. <mar...@di...>]

No, it was nasty to start with and this just makes it even nastier.  I
think the cleaner way would be to do something like this:

struct sillystruct {
	struct iax2_frame fr2;
	unsigned char buffer[4096];
} tmp;

and then reference tmp.fr2 and tmp.buffer;

Mark

On 12 Jun 2003, Steve Kann wrote:

>
> Mark,
>
>     Here's a good one, that took a bit to figure out also.  This problem
> only occurs with MacOSX, although it just depends on which way the stack
> grows..
>
> in iax_send, you have the following code:
>         unsigned char buffer[4096];             /* Buffer -- must
> preceed fr2 */
>         struct iax_frame fr2;
>         struct iax_frame *fr;
>
> and later, you do this:
>         if (now) {
>                 fr = &fr2;
>         } else
>                 fr = iax_frame_new(DIRECTION_OUTGRESS, f->datalen);
>         if (!fr) {
>                 IAXERROR "Out of memory\n");
>                 return -1;
>         }
>
>         fprintf(stderr, "now=%d, fr=%x, &fr2=%x\n", now, fr, &fr2);
>         fprintf(stderr, "f->datalen=%d\n", f->datalen);
>
>         /* Copy our prospective frame into our immediate or
> retransmitted wrapper */
>         iax_frame_wrap(fr, f);
>
>         fprintf(stderr, "now=%d, fr=%x, &fr2=%x\n", now, fr, &fr2);
>
>
> (fprintfs are mine) which if (now=1) and f has data, copies some items
> from f into fr2, and then copies data to from f to fr.  This data ends
> up past the end of fr2, which you account for, on machines with one
> stack direction, with the buffer on the stack.
>
> So, I think it would be better to just do this instead:
>         double buffer[1024];             /* Buffer -- does double
> guarantee us proper alignment? */
>         struct iax_frame *fr;
>
> [...]
>
>        if (now) {
>                 fr = (struct iax_frame *)&buffer;
>         } else
>                 fr = iax_frame_new(DIRECTION_OUTGRESS, f->datalen);
>         if (!fr) {
>                 IAXERROR "Out of memory\n");
>                 return -1;
>         }
>
>         fprintf(stderr, "now=%d, fr=%x\n", now, fr);
>         fprintf(stderr, "f->datalen=%d\n", f->datalen);
>
>         /* Copy our prospective frame into our immediate or
> retransmitted wrapper */
>         iax_frame_wrap(fr, f);
>
>         fprintf(stderr, "now=%d, fr=%x\n", now, fr);
>
>
> Does this seem like it will be more portable?
>
> It works for me on MacOSX/PPC, Linux/x86, Win2K/x86.
>
> Attached also please find my current diff between my local libiax2 and
> digium's CVS.  It is still mostly portability fixes, plus the two
> bugfixes (this one, and the buf[len-1] = 0 issue).
>
> Next on the list: using IAX2, for some reason the DNID isn't being
> honored.  This is kinda strange, because using "iax2 debug" on the
> console of a * server, it shows the DNID properly, but I still end up in
> the "s" extension for the context, instead of the requested extension..
>
>
> -SteveK
>
>
>
>
> --
>   Steve Kann - Chief Engineer - 520 8th Ave #2300 NY 10018 -  (212) 533-1775
>                 HorizonLive.com - collaborate . interact . learn
>    "The box said 'Requires Windows 95, NT, or better,' so I installed Linux."
>