Re: [Qemu-devel] [PATCH V2 2/5] Add WIN32 platform support for backing_file_loop_check()

[Fam Zheng]

On Mon, 07/15 14:09, Xu Wang wrote:
> 2013/7/10 Fam Zheng <address@hidden>
> 
> > On Mon, 07/08 03:26, Xu Wang wrote:
> > > +        error_report("get file %s stat error.", path);
> > > +        return -1;
> > > +    }
> > > +    if (GetFullPathName(path, MAX_PATH_LEN, pbuf, &p) != 0) {
> > How big is MAX_PATH_LEN?
> > MSDN: If the buffer is too small to contain the path, the return value
> > is the size, in TCHARs, of the buffer that is required to hold the path
> > and the terminating null character. Please try to handle this case. (And
> > is pbuf NULL terminated in this case?)
> >
> This is really a hard desicion to set value of it because length of path on
> Windows
> could be unlimited. So here I just set an value and want to get some tips
> from others.
> Now it's set as 8192 but I missed it when I made this patch.
> 

Yes, if you use heap allocated buffer, you can work with longer
filename. If you use fixed length buffer, ideally you should detect
whether return value is greater than your buffer size: in this case the
pbuf content is invalid (or incomplete), so your hash computation below
is inaccurate, consequentially false alarm.

-- 
Fam