[Need help/Question] How to write ssh-agent service

[TornaxO7]

Hello! I'm trying to write a ssh-agent service file which should start a ssh-agent for me.
I've the following file at the moment:
~/.config/dinit.d/ssh-agent:

type = process
command = /usr/bin/ssh-agent -D -a ~/.cache/ssh/ssh-agent.socket
restart = true

but if I do dinitctl start ssh-agent I'm seeting the following messages:

dinit: Service ssh-agent process terminated with exit code 1
[STOPPD] ssh-agent
[  OK  ] ssh-agent
dinit: Service ssh-agent process terminated with exit code 1
[STOPPD] ssh-agent
[  OK  ] ssh-agent
dinit: Service ssh-agent process terminated with exit code 1
[STOPPD] ssh-agent
[  OK  ] ssh-agent
dinit: Service ssh-agent process terminated with exit code 1
[STOPPD] ssh-agent
dinit: Service ssh-agent restarting too quickly; stopping.
[FAILED] ssh-agent

do you have an idea what I'm doing wrong?

[TornaxO7]

Sadly ssh-agent doesn't provide an error message (output from dinitctl status ssh-agent):

Service: ssh-agent
    State: STOPPED (terminated; exited - status 1)

[mobin-2008]

Hi.
It looks like you want to use dinit as user service manager.
Please check these few:

1. Run command in shell & check result
2. set logfile = log-file-path in your service (Example: logfile = ~/templog) then restart it & check your logfile

I converted your issue to discussion; because its better place to talk about your issue (For example you can set a reply as answer).

[TornaxO7]

Ok, so I changed ~/.config/dinit.d/ssh-agent to:

type = process
command = eval "$(ssh-agent)"
restart = true
logfile = ~/.cache/ssh/log.log

since doing eval "$(ssh-agent)" works if I execute it manually. But running dinitctl start ssh-agent gives me the following:

Service 'ssh-agent' failed to start.

Running dinitctl status ssh-agent returns the following:

Service: ssh-agent
    State: STOPPED (could not be launched)
        Stage: setting up standard input/output descriptors
        Error: No such file or directory

I'm a little bit irritated by this o.O

[mobin-2008]

make sure you have ~/.cache/ssh after if dont work try dinitctl reload ssh-agent

[TornaxO7]

Hm... it works fine now but it tops right away. I think that ssh-agent is supposed to be in a service 🤔 I'll look for another solution but thank your for your time!

[mobin-2008]

What do you mean?
I think you mistake to choose right type for your service. ssh-agent seems like one-time by default; if you need ssh-agent to be supervised by dinit; run ssh-agent with -D flag; from ssh-agent man page:

 -D      Foreground mode.  When this option is specified, ssh-agent will not fork

and everythink must be ok

[mobin-2008]

@TornaxO7 Have a nice day/night :)

[TornaxO7]

@TornaxO7 Have a nice day/night :)

Thank you, you too c(^-^)c

[davmac314]

type = process should be used for processes which are long-lived; ssh-agent in its default mode forks and the original process terminates, which is why the service stops straight away. The -D command line argument should prevent this, as mobin-2008 suggested. However, you need a way to capture the environment variables (particularly SSH_AUTH_SOCK) that it outputs.

One way to do that would be to have ssh-agent run a script which then stores the relevant environment variables back in dinit's environment (via dinitctl setenv). ssh-agent accepts a program to run as an argument.

The reason that command = eval "$(ssh-agent)" doesn't work is because the command is not a shell command and doesn't support the $( ... ) subshell syntax.

[davmac314]

Actually running a script under ssh-agent doesn't work as well as it might since ssh-agent will terminate when the script does. With that in mind I would instead suggest running as a type = scripted service, with something like (untested):

type = scripted
command = ssh-agent-script.sh start
stop-command = ssh-agent-script.sh stop

and in ssh-agent-script.sh:

#!/bin/sh
if [ "$1" == "start" ]; then
    eval "$(ssh-agent)"
    dinitctl setenv SSH_AUTH_SOCK SSH_AGENT_PID
elsif [ "$1" == "stop" ]; then
    ssh-agent -k
    dinitctl setenv SSH_AUTH_SOCK="" SSH_AGENT_PID=""
fi

[TornaxO7]

That's an interesting idea, I'll look what I can do, thank you for this information!

[Duncaen]

I just use a static location for the socket (-a flag) so I can just export the variable from my shell profile, I don't think there is any value in the "tmp" path unless you run multiple ssh-agents.

[TornaxO7]

Does $HOME/.cache/ssh exist?

Yes, output of pwd:

/home/tornax/.cache/ssh

Have you unloaded, the service?

I only started it with dinitctl start ssh-agent because it always "crashed"/stopped due to the error above if I'm right, because it's saying:

Service 'ssh-agent' failed to start.

if I run dinitctl start ssh-agent.

[Duncaen]

$ dinitctl unload ssh-agent
$ dinitctl start ssh-agent

[TornaxO7]

Oh, the service is now working but I'm still getting the error:

Error connecting to agent: No such file or directory

if I use ssh-add 🤔

[Duncaen]

You have to export SSH_AUTH_SOCK=$HOME/.cache/ssh/ssh-agent.socket in your shells environment.

[TornaxO7]

Yay! It's working now! Thank you sir :)

[alecStewart1]

I hate to come to an issue that's already solved, but I'm running into issues doing this myself on Chimera Linux with Nushell as my shell.

I have:

The env file:

HOME="/home/alec"
SSH_AUTH_SOCK="$HOME/.cache/ssh/ssh-agent.socket"

The ssh-agent service file:

type = process
env-file = /home/alec/.config/dinit.d/env
command =  /usr/sbin/ssh-agent -D -a $SSH_AUTH_SOCK
stop-command = /usr/sbin/ssh-agent -k
logfile = $HOME/.cache/ssh/ssh-agent.log

But the logs keep reporting:

unix_listener: cannot bind to path "/home/alec/.cache/ssh/ssh-agent.socket": No such file or directory

Despite that file existing:

❯ ls /home/alec/.cache/ssh/ssh-agent.socket
╭───┬────────────────────────────────────────┬──────┬──────┬───────────────╮
│ # │                  name                  │ type │ size │   modified    │
├───┼────────────────────────────────────────┼──────┼──────┼───────────────┤
│ 0 │ [/home/alec/.cache/ssh/ssh-agent.socket](file:///home/alec/.cache/ssh/ssh-agent.socket) │ file │  0 B │ 4 minutes ago │
╰───┴────────────────────────────────────────┴──────┴──────┴───────────────╯

Is this a permissions issue?

[capezotte]

The quote character isn't treated specially in dinit environment files, you init script runs as if you had invoked

/usr/sbin/ssh-agent -D -a "\"$HOME/.cache/ssh/ssh-agent.socket\""

in a shell. Notice how the double quotes are absent in this error message (shell):

$ /usr/sbin/ssh-agent -D -a "$HOME/.cache/ssh/ssh-agent.socket"
unix_listener: cannot bind to path /home/user/.cache/ssh/ssh-agent.socket: No such file or directory

Remove the quotes in the environment file and it should work.

---

ssh-agent -k is a glorified kill wrapper, you don't need to use it as a stop-command with a proper supervisor.