driver_wext.c memcpy problem

[Pavel Roskin]

On Thu, 2009-04-30 at 16:42 -0700, Dmitry Shmidt wrote:
> Hi,
> 
> In driver_wext.c in function there is memcpy that has overlapping
> areas :
> struct wpa_scan_results * wpa_driver_wext_get_scan_results(void *priv)
> {
> ...
> if (wext_19_iw_point(drv, iwe->cmd)) {
>             /* WE-19 removed the pointer from struct iw_point */
>             char *dpos = (char *) &iwe_buf.u.data.length;
>             int dlen = dpos - (char *) &iwe_buf;
>             os_memcpy(dpos, pos + IW_EV_LCP_LEN,   <<<<<<<<<<
>                   sizeof(struct iw_event) - dlen);
>         } else {
>             os_memcpy(&iwe_buf, pos, sizeof(struct iw_event));
>             custom += IW_EV_POINT_OFF;
>         }
>  ...
> }
> 
> It didn't work for me so I needed to exchange it with memmove() call.

Actually, there is a function os_memmove() that should do it.

> I am just curious how it worked for other people ? Is it possible that
> most memcpy() lib functions know how to handle overlapping areas ?

Maybe it just iterates over the memory in the direction that we need.

> Anyway it is not a mandatory memcpy() functionality.

I agree.

-- 
Regards,
Pavel Roskin