Re: [PATCH v2] Cygwin: clipboard: Fix a bug in read().

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Dec  7 23:00, Takashi Yano wrote:
> - Fix a bug in fhandler_dev_clipboard::read() that the second read
>   fails with 'Bad address'.
> 
> Addresses:
>   https://cygwin.com/pipermail/cygwin/2021-December/250141.html
> ---
>  winsup/cygwin/fhandler_clipboard.cc | 2 +-
>  winsup/cygwin/release/3.3.4         | 6 ++++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
>  create mode 100644 winsup/cygwin/release/3.3.4
> 
> diff --git a/winsup/cygwin/fhandler_clipboard.cc b/winsup/cygwin/fhandler_clipboard.cc
> index 0b87dd352..ae10228a7 100644
> --- a/winsup/cygwin/fhandler_clipboard.cc
> +++ b/winsup/cygwin/fhandler_clipboard.cc
> @@ -229,7 +229,7 @@ fhandler_dev_clipboard::read (void *ptr, size_t& len)
>        if (pos < (off_t) clipbuf->cb_size)
>  	{
>  	  ret = (len > (clipbuf->cb_size - pos)) ? clipbuf->cb_size - pos : len;
> -	  memcpy (ptr, &clipbuf[1] + pos , ret);
> +	  memcpy (ptr, (char *) &clipbuf[1] + pos, ret);

I'm always cringing a bit when I see this kind of expression. Personally
I think (ptr + offset) is easier to read than &ptr[offset], but of course
that's just me.  If you agree, would it be ok to change the above to

  (char *) (clipbuf + 1)

while you're at it?  If you like the ampersand expression more, it's ok,
too, of course.  Please push.


Thanks,
Corinna