[PATCH v2] Cygwin: clipboard: Fix a bug in read().
Mark Geisert
mark@maxrnd.com
Wed Dec 8 09:43:45 GMT 2021
Takashi Yano wrote:
[...]
> I think the following patch makes the intent clearer.
> What do you think?
>
>
> From d0aee9af225384a24ac6301f987ce2e94f262500 Mon Sep 17 00:00:00 2001
> From: Takashi Yano <takashi.yano@nifty.ne.jp>
> Date: Wed, 8 Dec 2021 17:06:03 +0900
> Subject: [PATCH] Cygwin: clipboard: Make intent of the code clearer.
>
> ---
> winsup/cygwin/fhandler_clipboard.cc | 4 ++--
> winsup/cygwin/include/sys/clipboard.h | 1 +
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/winsup/cygwin/fhandler_clipboard.cc b/winsup/cygwin/fhandler_clipboard.cc
> index 05f54ffb3..65a3cad97 100644
> --- a/winsup/cygwin/fhandler_clipboard.cc
> +++ b/winsup/cygwin/fhandler_clipboard.cc
> @@ -76,7 +76,7 @@ fhandler_dev_clipboard::set_clipboard (const void *buf, size_t len)
> clipbuf->cb_sec = clipbuf->ts.tv_sec;
> #endif
> clipbuf->cb_size = len;
> - memcpy (&clipbuf[1], buf, len); // append user-supplied data
> + memcpy (clipbuf->data, buf, len); // append user-supplied data
>
> GlobalUnlock (hmem);
> EmptyClipboard ();
> @@ -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, (char *) (clipbuf + 1) + pos, ret);
> + memcpy (ptr, clipbuf->data + pos, ret);
> pos += ret;
> }
> }
> diff --git a/winsup/cygwin/include/sys/clipboard.h b/winsup/cygwin/include/sys/clipboard.h
> index 4c00c8ea1..b2544be85 100644
> --- a/winsup/cygwin/include/sys/clipboard.h
> +++ b/winsup/cygwin/include/sys/clipboard.h
> @@ -44,6 +44,7 @@ typedef struct
> };
> };
> uint64_t cb_size; // 8 bytes everywhere
> + char data[];
> } cygcb_t;
>
> #endif
Sigh. I guess it's not possible to keep rid of a data item like I'd hoped. At
least "data[]" is cleaner than the historical "data[1]" here. If you call the
item cb_data I can live with it.
Thanks all for the discussion.
..mark
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