wswrapper:
Getting the wswrapper.c LD_PRELOAD model working has turned out to
involve too many dark corners of the glibc/POSIX file descriptor
space. I realized that 95% of what I want can be accomplished by
adding a "wrap command" mode to wsproxy.
The code is still there for now, but consider it experimental at
best. Minor fix to dup2 and add dup and dup3 logging.
wsproxy Wrap Command:
In wsproxy wrap command mode, a command line is specified instead
of a target address and port. wsproxy then uses a much simpler
LD_PRELOAD library, rebind.so, to move intercept any bind() system
calls made by the program. If the bind() call is for the wsproxy
listen port number then the real bind() system call is issued for
an alternate (free high) port on loopback/localhost. wsproxy then
forwards from the listen address/port to the moved port.
The --wrap-mode argument takes three options that determine the
behavior of wsproxy when the wrapped command returns an exit code
(exit or daemonizing): ignore, exit, respawn.
For example, this runs vncserver on turns port 5901 into
a WebSockets port (rebind.so must be built first):
./utils/wsproxy.py --wrap-mode=ignore 5901 -- vncserver :1
The vncserver command backgrounds itself so the wrap mode is set
to "ignore" so that wsproxy keeps running even after it receives
an exit code from vncserver.
wstelnet:
To demonstrate the wrap command mode, I added WebSockets telnet
client.
For example, this runs telnetd (krb5-telnetd) on turns port 2023
into a WebSockets port (using "respawn" mode since telnetd exits
after each connection closes):
sudo ./utils/wsproxy.py --wrap-mode=respawn 2023 -- telnetd -debug 2023
Then the utils/wstelnet.html page can be used to connect to the
telnetd server on port 2023. The telnet client includes VT100.js
(from http://code.google.com/p/sshconsole) which handles the
terminal emulation and rendering.
rebind:
The rebind LD_PRELOAD library is used by wsproxy in wrap command
mode to intercept bind() system calls and move the port to
a different port on loopback/localhost. The rebind.so library can
be built by running make in the utils directory.
The rebind library can be used separately from wsproxy by setting
the REBIND_OLD_PORT and REBIND_NEW_PORT environment variables
prior to executing a command. For example:
export export REBIND_PORT_OLD="23"
export export REBIND_PORT_NEW="65023"
LD_PRELOAD=./rebind.so telnetd -debug 23
Alternately, the rebind script does the same thing:
rebind 23 65023 telnetd -debug 23
Other changes/notes:
- wsproxy no longer daemonizes by default. Remove -f/--foreground
option and add -D/--deamon option.
- When wsproxy is used to wrap a command in "respawn" mode, the
command will not be respawn more often than 3 times within 10
seconds.
- Move getKeysym routine out of Canvas object so that it can be called
directly.
Rename the $() selector to $D() so that it doesn't collide with
the jQuery name.
The API change is that the 'target' option for Canvas and RFB objects
must now be a DOM Canvas element. A string is no longer accepted
because this requires that a DOM lookup is done and the Canvas and RFB
should have no UI code in them. Modularity.
Only call encode_message when the WebSockets object is actually
ready to send. Otherwise multiple base64 encode sequences can be
encoded into the same WebSockets frame. This causes the C version of
wsproxy to crash and the python version to ignore the subsequent
base64 sequence(s).
Thanks to Colin Dean (xvpsource.org) for finding this and helping
track it down.
- Add meta tag to vnc.html and vnc_auto.html so that if Chrome Frame
is installed, it is used.
- Add detection to default_controls.js that shows a message with
a Chrome Frame install link if the user is using a version of IE
without Canvas support.
- Fix web.py so that requests have their connection closed after they
are completed. This has been a bug for a while but it prevents
Chrome Frame from working because Chrome Frame doesn't activate
until the initial request connection closes.
This is WebKit bug https://bugs.webkit.org/show_bug.cgi?id=46319
The workaround is to wrap Canvas render functions with a function that
sets a flush timer. The flush function sets the right margin and then
1ms later sets it back. This triggers the canvas to redraw with the
correct contents.
Two downsides:
- rendering is slower, but only on the busted versions of webkit.
Correct and useful is better than fast and useless.
- There is a barely perceptible jitter of the control buttons because
the canvas size is changing by one pixel.
To support this functionality, we also have to read out the exact
webkit version from the user agent in the render engine detection code
in include/util.js.
- Make sure that canvas exists (i.e. didn't throw an error) before
trying to call canvas method get_canvas_uri.
- Typos in HTML render engine debug output.
- Split out ClientInitialisation state.
- In version 3.3 and 3.7, when the server has no auth (scheme
1), then we should skip from Authentication to ClientInitialisation.
- rQwait checks the receive queue to see if there is enough data to
satisfy the following request. If not it returns true (which is
almost always translated into an immediate return false by the
caller).
- rQwait is called quite a bit and this generally allows 4 lines to
become 1 line where it is called.
- rQwait allows simplification of cuttext processing. No global
tracking needed anymore.
Overall, about 60 lines less code.
DES is just used once during authentication and is not performance
sensitive so we save some space by generating and/or removing some
lookup tables. Also, shorten some very frequently used variables.
Shaves off about 100 lines.
- util.js that contains essential functions
- webutils.js that contains the GUI utility function.js
this helps to include noVNC in other project, especially Cappuccino Application
i
The decrypt functionality is never used so remove it. Also, we can
assume that we are always DES encrypting 16 characters which allows
several things to be simplified in DES.
Overall this removes about 80 lines of code.
- include/rfb.js: Keep track of the number of rects of each encoding
type and print them out when we close a connection (if 'info'
logging level).
- tests/vnc_perf.html: first pass at a noVNC based performance
benchmark.
- utils/wsproxy.py: Fix the output of the record filename.
- include/util.js: Add type and desc field to conf_default routine.
Make comment descriptions of settings into desc parameters that can
be queried. Also, use set_FOO in conf_default to set or coerce the
current setting so that we always have the right type for the value.
- include/rfb.js, include/default_config.js: add connectTimeout
setting to address situations with slow connections that may need
more than 2 seconds.
Yet another weird VNC server behavior: sending a failure and length
before the reason message. To calculated the length, the reason string
is already available, why not just send everything as one packet. Oh
well.
- include/canvas.js: When 'debug' logging, show browser detection
values.
- test/canvas.html: Only restore the canvas to it's starting state if
the logging level is not 'debug'.
- wsproxy.py: Append the session number to the record filename so that
multiple sessions don't stomp on each other.
In Safari, local cursor rendering is corrupt. In firefox 3.6.10, local
cursor rendering causes a segfault. Probable that the .cur format is
not 100% compliant (even though it works in Chrome and firefox 3.5 and
firefox 4.0). So just disable it by default until I can figure out how
to address the problems.
Add a new state 'disconnect' to reflect that we are not truly
'disconnected' until we get an onclose event. Add a disconnect timer
to match.
Handle disconnected cleanup better in updateState(). Anytime we enter
in a disconnect/disconnected state, make sure all running state is
cleaned up (WebSocket, timers, canvas).
Filed this issue for this bug:
http://github.com/gimite/web-socket-js/issues/issue/37
Right now the close() call only calls __flash.close() if readyState is OPEN.
But it should really call close any time that readyState is not CLOSED or
CLOSING.
The case I ran into is when I want to do the following:
1. make a test connection
2. tell the server to setup for a connection
3. connect again
I call close on the test connection, but since it is ignored when CONNECTING,
it eventually times out with a error. But by that time I have already issued a
new connection, it causes the new connection to fail. close() should cancel
CONNECTING state too.
Filed this bug about this issue:
http://github.com/gimite/web-socket-js/issues#issue/35
To work around the flash "recursive call" problem, WebSocket.as has
the onclose event disabled in the close() call and the javascript half
of the close() call does the onclose() call instead. This is fine, but
it needs to be asynchronous to act more like what happens with
a normal WebSockets object. The current behavior is that the onclose()
method is called inline (synchronously) when the close() is called and
this inconsistency make state handling more difficult.
web-socket-js now has all the functionality and fixes needed for noVNC
so remove the include/as3crypto_patched directory and the
include/web-socket-js/flash-src directory (i.e. the sources for
web-socket-js). This cleans up almost 3K from the include/ directory.
Update to web-socket-js build based on upstream (gimite/web-socket-js)
9e766377188.
The rfb variable wasn't available at the point settingsDisabled() was
being called since it was called inline with RFB() initialization. To
solve this we pass the updateState rfb variable so that the canvas can
be queried for setting the cursor_uri value.
When the documement/window is scrolled, the onMouseDisable routine was
not properly calculating the position to test whether to ignore the
event or not.
Joel Martin
Antoine Mercadal