Re: Capturing USB data?
- From: Joseph M. Newcomer <newcomer@xxxxxxxxxxxx>
- Date: Sun, 31 Aug 2008 10:40:30 -0400
See below...
On Sat, 30 Aug 2008 20:20:36 -0500, "Peter Olcott" <NoSpam@xxxxxxxxxxxxx> wrote:
****
"Joseph M. Newcomer" <newcomer@xxxxxxxxxxxx> wrote in
message news:8mpjb4pv8rv8vj19uhs728vbaf7r5gspp3@xxxxxxxxxx
See below...There is always a best approach, even if it is not very
On Sat, 30 Aug 2008 11:07:31 -0500, "Peter Olcott"
<NoSpam@xxxxxxxxxxxxx> wrote:
What is the best approach to capture all hardware****
(especially keyboard and mouse) inputs and also be able to
send these same hardware inputs to every OS/hardware
platform (especially Windows, Apple Mac OS X, and
Linux/Unix) ???
There isn't one.
good, there is always at least one that is better than the
alternatives.
There is always the least-worst approach. Least-worst may give the illusion of being
best, but it doesn't mean the approach is actually a good idea.
****
****
There is not what that is platform-independent, there is
not one that is
device-independent. As far as I know, and as far as I can
tell from the kind of behavior
I'm seeing, mice and keyboards have unique interface
specifications. In addition, the
ways of intercepting these events differ with the
operating system. Each is unique.
****
****
I was thinking about two basic approaches:
(1) USB hardware device that a USB Keyboard and Mouse plug
into, along with USB and Keyboard and Mouse drivers for
this
device.
There are several layers of protocol here
application <--> HID class <--> device minidriver <--> USB
class driver <--> USB
minidriver
The only standard within Windows is at the HID-class level
protocol. Below that, you have
no idea what the bits mean. But the Mac uses a different
software organization, and
Unix/linux use a different software organization.
Mac is now a flavor of Unix, under the covers.
But unlike most flavors of Unix, the Mac (based on the Mach kernel developed at CMU by
Rick Rashid, who is now the head of Microsoft research...is there an irony here?) puts its
device drivers in a different ring (I think ring 1), and therefore has a quite different
architecture from other flavors of Unix that leave all the drivers in ring 0.
****
****
Therefore, you will have to think of
each situation as being unique as far as the OS. And
anything below the device minidriver
is essentially random bits. You would have to emulate the
driver functionality on your
own, and there is not world enough and time for that.
****
(2) Modified versions of existing Keyboard/Mouse device****
drivers that provide for capturing and instantiating
events.
So how do you go to Microsoft, Logitech, etc. and say "I
want a copy of your mouse driver
code so I can modify it to support my product"?
Observation: with no success. Actually,
the MS mouse driver source might be in the DDK, but you
are in for a massive learning
curve to build drivers and modify them.
You could consider, in the MS world, building a mouse
filter driver and a keyboard filter
driver. You could probably succeed in doing one of these
in a couple months (they are
fairly straightforward, as drivers go).
But what would scare me, if I were providing oversight on
this kind of project, is that it
appears to have become an infinite time sink to make any
progress. It is now capable of
absorbing as many resources as you can throw at it into
the indefinite future.
Why does a low-level mouse hook or low-level keyboard hook
not do the job? Don't look for
an OS-independent solution; build the right abstract
interface and then worry about the
implementation on an OS-by-OS basis. For Windows, this is
a low-level hook. For the Mac
or linux, it is some other mechanism.
joe
*****
Yes that may be the best approach. Here is another idea:
http://en.wikipedia.org/wiki/Virtual_Network_Computing
That one certainly looks promising.
joe
****
Joseph M. Newcomer [MVP]Joseph M. Newcomer [MVP]
"Joseph M. Newcomer" <newcomer@xxxxxxxxxxxx> wrote in
message news:h3pib41j6fqt9jp6bvji0shqh3ar8sqi4u@xxxxxxxxxx
What does capturing every keystroke and mouse click have
to do with USB? Not all machines
have USB keyboards or USB mice. If your question was
"how
do I capture every keystroke
and mouse click?" that is quite a DIFFERENT question
than
"how do I capture USB input?"
For example, the format of the USB packets from
different
vendors can be different; their
low-level drivers convert this information from their
(possibly proprietary, most likely
undocumented) format to mouse clicks and keystrokes, so
capturing the USB data isn't going
to tell you very much.
Adapting keyboard and mouse drivers is not at all the
same
as capturing USB data.
Observation: sometimes, when I reboot, my mouse is
completely "reprogrammed"; the scroll
wheel is interpreted as mouse clicks, mouse clicks are
interpreted as mouse motion, etc.
This is because on boot it did not properly communicate
with the mouse because of the KVM
switch. If I switch to another computer and switch
back,
all is fixed. This suggests
that different brands of mice use different
communication
packet encodings.
So I'm not sure that capturing USB packets is a
particularly valuable, or even useful,
concept here. A low-level keyboard and mouse hook
should
do the job (but note that on
Vista, security may prevent getting at these unless you
are running at high integrity)
It is important to state the question, not ask for how
to
achieve some implementation
detail. I answered your question, but in the context of
"how do I capture USB input to
see mouse and keyboard events?" the answer is "this is
the
wrong question to be asking"
Note that you would also have to intercept all the
proprietary packets for tablets,
joysticks, game paddles, touch screens, and other
devices
which create events that can
generate character data or request a program to
activate.
In fact, your program would
have to understand the proprietary USB encoding of every
HID device in the world.
When something as vanilla as a Microsoft mouse and a
Logitech mouse send different
packets, I think this is definitely the wrong approach.
joe
On Sat, 30 Aug 2008 09:51:38 -0500, "Peter Olcott"
<NoSpam@xxxxxxxxxxxxx> wrote:
What I really need to do is to capture every keystrokeJoseph M. Newcomer [MVP]
and
mouse click and also be able to feed these to the
system.
I
already know how to do this for MS Windows.
I need to generalize this capability across all other
platforms, especially Mac OS X, and Linux. My current
thinking is adapting a keyboard and mouse driver on
these
platforms. I would probably start with Intel/Windows
because
this is the platform that I am the most familiar with.
I was thinking that restricting my research to the USB
interface might simplify things since all three
platforms
provide this interface.
I would eventually want this same capability literally
across every platform, including hand-held devices.
Initially this capability may be limited to devices that
provide a USB interface for their hardware input
device(s),
eventually this restriction would also be removed.
"David Webber" <dave@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote
in
message news:u5ATL2qCJHA.3576@xxxxxxxxxxxxxxxxxxxxxxx
"Peter Olcott" <NoSpam@xxxxxxxxxxxxx> wrote in message
news:9kbuk.1863$Fm6.1271@xxxxxxxxxxxxxxx
How would I go about capturing all of the data sent
to
a
particular USB port?
I have never done this in any general sense, but I can
confirm that signals from a MIDI piano keyboard
plugged
into a USB port are automatically picked up by the
usual
MIDI-in routines of the Windows Multimedia API.
Dave
--
David Webber
Author of 'Mozart the Music Processor'
http://www.mozart.co.uk
For discussion/support see
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