Sending Signal to remote process

[Mamfelt]

Perhaps a multi-step process. How about...

After you have PID of the ssh session, run a second query looking for the PID of processes that have PPID equals the remote ssh PID just found. 

Sent from my iPhone

> On 23 Jan 2018, at 15:33, Peter Stuge <peter at stuge.se> wrote:
> 
> Thomas Güttler wrote:
>> Example:
>>   ssh root at localhost /root/print-signal.py
>> 
>> Get PID of ssh:
>>    ps aux| grep print-signal
>> 
>> Kill the matching ssh process:
>>    kill pid-of-ssh
>> 
>> Unfortunately only the ssh process itself gets the signal, not the
>> remote command (print-signal.py).  The remote command does not
>> terminate :-(
>> 
>> How can I make ssh "forward" the SIGTERM signal to the remote command?
>> 
>> See https://stackoverflow.com/questions/48377993/forwards-sigterm-over-ssh
>> 
>> According to this[1] answer, openssh does not implement this.
> 
> Correct, that channel message is currently not supported by OpenSSH.
> 
> 
>> It would be realy great if openssh could forward the signal to the
>> remote-command.
> 
> Yes and no.
> 
> I agree that sending signals to remote processes (channels, actually)
> can be very useful.
> 
> But I absolutely do not want to lose the ability to send signals to
> the ssh client itself on the system where it is running.
> 
> So "remote signals" need to be separate from local signals - meaning
> that they probably need some other interface than kill().
> 
> This gets complicated. How do you know which channel to send the
> signal to? One ssh process can have many open channels.
> 
> So whatever interface is used would possibly also have to allow
> enumerating open channels, but obviously only for the respectiveuser.
> 
> How to accomplish that in a portable manner? Maybe a AF_UNIX socket
> with a custom protocol?
> 
> I don't think there exists any development for such an interface, and 
> it's not a trivial thing.
> 
> 
> Meanwhile, what you can do is make /root/print-signal.py on the
> output its own pid to stdout which you save in your software/script
> on the client side, and open a second channel (e.g. using multiplexing):
> 
> ssh root at localhost 'kill -TERM insert_pid_here'
> 
> which sends the signal.
> 
> This expands on the second point in the stackoverflow answer.
> 
> 
> //Peter
> 
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