[bmsleight]

Hi

[TL/DR] Running a command from KUAL using pipes not as expected

I have a PI 3B+ running openwrt and four Amazon Kindle Paperwhite 1 Wi-Fi, I have v2.7.23-g9f3694a of KUAL installed, with USB networking. I can successfully transfer data between machines, by ssh into each machine and running scripts with the scripts and applications using netcat (aka nc).

I am trying to convert to an KUAL extension so finish the project and release. However I must be doing something wrong with piping.

Minimal working example from SSH - not KUAL

On a separate machine (running OpenWRT)

root@OpenWrt:~# mkfifo /tmp/example.pipe
root@OpenWrt:~# cat /tmp/example.pipe  | netcat -l -vvv  -p  5001 &
root@OpenWrt:~# Listening on any address 5001

Note: "Listening on any address 5001" is the verbose output of netcat

ssh onto Kindle

[root@kindle root]# nc 192.168.1.126 5001 | tee -i

On the OpenWrt machine, then issue an echo

root@OpenWrt:~# mkfifo /tmp/example.pipe
root@OpenWrt:~# cat /tmp/example.pipe  | netcat -l -vvv  -p  5001 &
root@OpenWrt:~# Listening on any address 5001
Connection from 192.168.1.105:47765
root@OpenWrt:~# echo "hi" >/tmp/example.pipe 
root@OpenWrt:~#

On Kindle I get:-

[root@kindle root]# nc 192.168.1.126 5001 | tee -i  
hi

Nb: Note pipe is still open and I can continue to send data from openwrt machine

Minimal working example Using KUAL


Now again using KUAL, using extension as:-

[root@kindle root]# cat /mnt/us/extensions/OkMonitor/menu.json 
{
	"items": [
	{
		"name": "NC Examples",
		"priority": -998,
		"items": [
		{
			"name": "nc example 1",
			"action": "nc 192.168.1.126 5001 | tee -i ",
			"internal": "Example"
		}
		]
	}
	]
}
[root@kindle root]#

Same commands

root@OpenWrt:~# mkfifo /tmp/example.pipe
root@OpenWrt:~# cat /tmp/example.pipe  | netcat -l -vvv  -p  5001 &
root@OpenWrt:~# Listening on any address 5001

Then Kindle: KUAL -> NC Examples -> nc example 1

root@OpenWrt:~# mkfifo /tmp/example.pipe
root@OpenWrt:~# cat /tmp/example.pipe  | netcat -l -vvv  -p  5001 &
root@OpenWrt:~# Listening on any address 5001
Connection from 192.168.1.105:59820
Total received bytes: 0
Total sent bytes: 0

In the second example nc sucessfully but then disconnects. I require nc to remain open. The only difference is that in the first example I running the command when conencted via ssh, the second via KUAL menu.

I need nc to pipe to a different compiled application, but using tee as the application in this examples.

Things I have tried:-

• openWRT difference option -c, -k
• openWRT difference version of netcat, nc, ncat
• From KUAL run a script the ssh localhost then trying to pipe
• From login -F root
• on Kindle tee -i in the pipe
• Pulling hair out and eating chocolate.

Any pointers would be great. Or any ideas how I can debug further.



Thanks,
Brendan