Using LabView to SSH to a remote Linux unit

[jimbobaggies]

I need to remotely connect to a Linux machine using SSH

IP: 192.168.5.xx,

Port: 22

User: *****

Password: *****

Then then I want to send some commands "lsusb[...]" and "sudo lspci[...]", and read back the responses.

Are there any prewritten vi's for this, or can anyone share what they have done to overcome this?

[Yamaeda]

There are a couple of SSH packages in VIPM. I haven't tried them myself though.

[JePe1]

I've used the Putty command-line tools for this in the past.

https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

The device we were talking to needed some RSA keys for security, and the customer was able to provide .ppk files designed for Putty.

The command line for SSH w/ security keys was (example):

@echo OFF
echo n | "C:\Program Files\PuTTy\plink.exe" -i "C:\SSH\keys.ppk" root@192.168.1.2 echo "Hello World!"

Or without all the security key stuff:

@echo OFF
"C:\Program Files\PuTTy\plink.exe" root@192.168.1.2 echo "Hello World!"

There's also a command line tool for SCP file transfer, example:

@echo OFF
echo n | "C:\Program Files\PuTTy\pscp.exe" -scp -i "C:\SSH\keys.ppk" "C:\SSH\filetocopy.txt" root@192.168.1.2:/root/scripts/filetocopy.txt

It looks like they added native SSH into LabVIEW in version 2021. I've never played with it -- we are still on 2019 and I believe Putty was NI's recommended method back then.

[cordm]

LabVIEW 2021 includes support for SFTP and SSH. You can find the palettes under Data Communication >> Protocols.

[jimbobaggies]

There is only SFTP palette no SSH, but I am able to use this to connect. There is nothing in the palette for send receive so I can issue commands and read the response. In serial this is read write.

[cordm]

LabVIEW opens and closes the connection for each command, you would have to dig in deeper or use a different API if you want to reuse a connection. 

The VIs are here: <labview>\vi.lib\net\SSH\NI_SSH.lvlib

LabVIEW SSH

Works for me on 64 bit LabVIEW.

Tim Cannon uses LabSSH2 for his RT SSH API commands, might be worth a look for you: https://gitlab.com/cannontim/rt-ssh-api

[jimbobaggies]

Right, so I am using LIBSSH2 for LabVIEW Toolkit, and can successfully login, send commands and read the response. Where I am stuck now is using "sudo", as it will expect the password again, not sure how I do this. I am using a string array into a loop to send commands, but don't know how to get the password in and read the required respons.

[PhillipBrooks]

When using the SSH.NET library, I used the technique in this stackoverflow post:

https://stackoverflow.com/questions/40918265/how-to-su-with-ssh-net

Specifically, you echo the password and then pipe that to the sudo command with a -S argument and then the command to execute.

If you log your session, the password will be included in clear text. Not generally a good idea.

Alternately, if you have multiple commands to run and evaluate as super user, you can use interactive mode with sudo -i

You will need to perform a read after writing the command and look for a message requesting the  password (I used regex with this pattern \[sudo\] password for (\w+)\: ).

If found, you send the password with a new line appended. If you have previously elevated the session to super user, you will not get a prompt for the password (regex will return nothing)

Once you are done, you can send a ^D or a logout command to revert back the the standard user shell with standard permissions.