[Qemu-devel] vnc: client_cut_text regression

[Amit Shah]

Hello,

client_cut_text, which is called from protocol_client_msg(), only
gets valid buffers the datalen is <= 19999. For values above that,
it's called with the len as 0.

It's easy to reproduce: since client_cut_text doesn't do anything
yet, just put an fprintf with the len that was passed in the
client_cut_text() function and try copying some values to the clipboard
on the host with the vncviewer open. Watch for the printfs.

I couldn't track down the regression to any recent commits in vnc.c; I
remember it working about a month ago though. Enabling debug shows some
messages (len xxxx is mine in client_cut_text) which show there's no
data in the len=20000 (which prints out as len=0) case.

I also tried with an older vnc client to check if it was a regression in
the vncviewer; got the same behaviour there as well.

VNC_DEBUG=1
Wrote wire 0x2649440 1830 -> 1830
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 10
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 4096
Read plain 0x2207800 size 20480 offset 4096
Read wire 0x2208800 4096 -> 4096
Read plain 0x2207800 size 20480 offset 8192
Read wire 0x2209800 4096 -> 4096
Read plain 0x2207800 size 20480 offset 12288
Read wire 0x220a800 4096 -> 4096
Read plain 0x2207800 size 20480 offset 16384
Read wire 0x220b800 4096 -> 3623
len 19999
Wrote wire 0x2649440 430 -> 430
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 10
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 6
Wrote wire 0x2649440 1797 -> 1797

Wrote wire 0x2649440 1334 -> 1334
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 10
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 8
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 8
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 8
len 0
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 6
Wrote wire 0x2649440 1330 -> 1330
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 10
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 6
Read plain 0x2207800 size 20480 offset 0
Read wire 0x2207800 4096 -> 6
Wrote wire 0x2649440 1328 -> 1328

                Amit