opengtoolkit-developers

LabVIEW SSH Tools

[Jim K. <ji...@ji...>]

Hello all,

I was wondering if anyone has done any work with LabVIEW and SSH.  I was
looking at the PuTTY FAQ to see if there was a programmatic interface =
and
saw the following:

<http://www.chiark.greenend.org.uk/~sgtatham/putty/faq.html#A.4.3>

##############=20
Probably your best bet is to use Plink, the command-line connection =
tool. If
you can start Plink as a second Windows process, and arrange for your
primary process to be able to send data to the Plink process, and =
receive
data from it, through pipes, then you should be able to make SSH =
connections
from your program.

This is what CVS for Windows does, for example.
##############

I haven't done any works with pipes in Windows and did a little bit of
research.  I found the following on MSDN:

<http://msdn.microsoft.com/library/default.asp?url=3D/library/en-us/dllpr=
oc/ba
se/creating_a_child_process_with_redirected_input_and_output.asp>

Has anyone gotten pipes working in LabVIEW?  Would anyone more C++ savvy
than myself be interested in working with me to get a generic "System =
Exec
w/ Pipes" working?  I envision a DLL that could be called from LabVIEW =
(or
maybe LabVIEW could call WinAPI DLLs directly) with functions for =
Spawning
the Process (the command-line executable), Reading from, and Writing to =
a
Pipe for communication with the running executable.

Regards,

-Jim

RE: LabVIEW SSH Tools

[Rolf K. <rol...@ci...>]

> -----Original Message-----
> From: Jim Kring [mailto:ji...@ji...]
> Sent: Sat, February 28, 2004 7:42 PM
> To: 'OpenGToolkit-Developers'
> Subject: LabVIEW SSH Tools
>=20
>=20
> Hello all,
>=20
> I was wondering if anyone has done any work with LabVIEW and=20
> SSH.  I was
> looking at the PuTTY FAQ to see if there was a programmatic=20
> interface and
> saw the following:
>=20
> <http://www.chiark.greenend.org.uk/~sgtatham/putty/faq.html#A.4.3>
>=20
> ##############=20
> Probably your best bet is to use Plink, the command-line=20
> connection tool. If
> you can start Plink as a second Windows process, and arrange for your
> primary process to be able to send data to the Plink process,=20
> and receive
> data from it, through pipes, then you should be able to make=20
> SSH connections
> from your program.
>=20
> This is what CVS for Windows does, for example.
> ##############
>=20
> I haven't done any works with pipes in Windows and did a little bit of
> research.  I found the following on MSDN:
>=20
> =
<http://msdn.microsoft.com/library/default.asp?url=3D/library/en-us/dllpr=
oc/base/creating_a_child_process_with_redirected_input_and_output.asp>

Has anyone gotten pipes working in LabVIEW?  Would anyone more C++ savvy
than myself be interested in working with me to get a generic "System =
Exec
w/ Pipes" working?  I envision a DLL that could be called from LabVIEW =
(or
maybe LabVIEW could call WinAPI DLLs directly) with functions for =
Spawning
the Process (the command-line executable), Reading from, and Writing to =
a
Pipe for communication with the running executable.

Regards,

-Jim



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RE: LabVIEW SSH Tools

[Rolf K. <rol...@ci...>]

Hi Jim
=20
> I haven't done any works with pipes in Windows and did a little bit of
> research.  I found the following on MSDN:
>=20
> =
<http://msdn.microsoft.com/library/default.asp?url=3D/library/en-us/dllpr=
oc/base/creating_a_child_process_with_redirected_input_and_output.asp>

>Has anyone gotten pipes working in LabVIEW?  Would anyone more C++ =
savvy
>than myself be interested in working with me to get a generic "System =
Exec
>w/ Pipes" working?  I envision a DLL that could be called from LabVIEW =
(or
>maybe LabVIEW could call WinAPI DLLs directly) with functions for =
Spawning
>the Process (the command-line executable), Reading from, and Writing to =
a
>Pipe for communication with the running executable.

I haven't done anything with pipes yet although it isn't really =
difficult.
The article you qoute seems fairly straight forward. I think the current
System Exec most probably uses pipes for the three standard IO handles =
to
get the StdIn/Out and Err at all. What is the problem is that you do not
get the handle back but just the entire text after execution of the =
command.

I think although it might be sort of possible to go directly from =
LabVIEW
to the Win32 API, it is a much better and smarter aproach to pack =
everything
into a DLL. Instead of returning the entire StdOut/Err text at once it =
would
return the three handles which can then be used by other DLL functions =
to
read and write to/from those handles.

The code as shown in above example would almost work for that already. =
At the
moment I'm busy getting the Generic PortIO device driver working (Well =
generic
in that it supports Port IO in direct fast and indirect slow mode (the =
one the
current LabVIEW PortIO functions support) and possibly low mem access, =
not
multiplattform although I got a Linux example too, just need to adapt it =
a bit
to get it working nicely with LabVIEW.) I hope I have it ready end of =
this week
and then I'll look into the inherited pipe system exec if nobody else =
stepped
up to it until then.

Rolf Kalbermatter

RE: LabVIEW SSH Tools

[Jim K. <ji...@ji...>]

Hi Rolf,

>=20
>=20
> Hi Jim
> =20
> > I haven't done any works with pipes in Windows and did a=20
> > little bit of research.  I found the following on MSDN:
> >=20
> >=20
> > =
<http://msdn.microsoft.com/library/default.asp?url=3D/library/en-us/dllp
> > =
roc/base/creating_a_child_process_with_redirected_input_and_output.asp
> >=20
>=20
> >Has anyone gotten pipes working in LabVIEW?  Would anyone more C++=20
> >savvy than myself be interested in working with me to get a generic=20
> >"System Exec w/ Pipes" working?  I envision a DLL that could=20
> >be called=20
> >from LabVIEW (or maybe LabVIEW could call WinAPI DLLs directly) with=20
> >functions for Spawning the Process (the command-line executable),=20
> >Reading from, and Writing to a Pipe for communication with=20
> the running=20
> >executable.
>=20
> I haven't done anything with pipes yet although it isn't=20
> really difficult. The article you qoute seems fairly straight=20
> forward. I think the current System Exec most probably uses=20
> pipes for the three standard IO handles to get the StdIn/Out=20
> and Err at all. What is the problem is that you do not get=20
> the handle back but just the entire text after execution of=20
> the command.

You are right, I think.  In fact, if you look at the "Pipes" function
palette VIs in LabVIEW for Unix/Linux, "Open System Command Pipe.vi" =
does
just that (asynchronous system exec call with pipe outputs for
Read/Write/Error).  I have attached an example which uses this method to
call plink (also included in the attachment).  I have tgz'ed (rather =
than
zip'ed) the archive to preserve the Unix file system executable bit of =
the
plink file.  I have also attached a screenshot (pipe2plink.png) of the
example code for those out there without LabVIEW for Unix/Linux (and the
needed "Pipes" VIs).  This is a simple terminal-like GUI App that allows =
you
to execute single link commands via the secure shell and displays the =
I/O in
a buffered string indicator.

>=20
> I think although it might be sort of possible to go directly=20
> from LabVIEW to the Win32 API, it is a much better and=20
> smarter aproach to pack everything into a DLL. Instead of=20
> returning the entire StdOut/Err text at once it would return=20
> the three handles which can then be used by other DLL=20
> functions to read and write to/from those handles.
>=20

Yes, I think so too.  I was noticing that the WinAPI functions use some
compund (struct) data structures that might be hard to pass into a CLF =
node
from LabVIEW.

> The code as shown in above example would almost work for that=20
> already. At the moment I'm busy getting the Generic PortIO=20
> device driver working (Well generic in that it supports Port=20
> IO in direct fast and indirect slow mode (the one the current=20
> LabVIEW PortIO functions support) and possibly low mem=20
> access, not multiplattform although I got a Linux example=20
> too, just need to adapt it a bit to get it working nicely=20
> with LabVIEW.) I hope I have it ready end of this week and=20
> then I'll look into the inherited pipe system exec if nobody=20
> else stepped up to it until then.
>=20
> Rolf Kalbermatter
>=20

OK, thanks.  I've also pinged a TortoiseCVS developer (who is also an =
OpenG
Developer ;-) about this.  I'm hoping to hear back soon.

-Jim

RE: LabVIEW SSH Tools

[Jim K. <ji...@ji...>]

Regarding TortoiseCVS and piping into Plink, here is a snip from an =
email I
got back from Ian:

###########

My first take used the WinAPI file functions to read/write pipes =
(ReadFile
and WriteFile).  I now see that the Tortoise project has now added POSIX
calls for the non-Win32 interface.  It might be possible to use POSIX =
calls
from msvcrt instead of Win32 calls from User32.

Both chunks of code are in the link below (see the "run" function about
two-thirds of the way down).  I'll take a quick peek at using execvp() =
from
LabVIEW.

<http://cvs.sourceforge.net/viewcvs.py/tortoisecvs/TortoiseCVS/src/cvsgui=
/cv
sgui_process.cpp?rev=3D1.7&view=3Dauto>

###########

-Jim