How do I set environment variables for dinit user services?

[ayushnix]

What is the equivalent of /etc/dinit/environment for dinit when it's started as a user service manager? The only method of importing environment variables in user services that I've found so far is the env-file option but the files in that case do not support variable substitution at all, the values have to be literal strings.

I'm using Chimera Linux with dinit version 0.19.3, although the man pages report 0.19.4pre.

Here's a user service I've written:

$ cat .config/dinit.d/ssh-agent
type = process
command = /usr/bin/ssh-agent -D -a $SSH_AUTH_SOCK
depends-ms: login.target
depends-ms: dinit-user-env
log-type = buffer

I tried making a user service which executes this script:

$ cat bin/dinit-user-env
#!/bin/sh

dinitctl setenv XDG_RUNTIME_DIR="${XDG_RUNTIME_DIR:-/run/user/$(id -u)}"
dinitctl setenv SSH_AUTH_SOCK="${SSH_AUTH_SOCK:-$XDG_RUNTIME_DIR/ssh-agent.socket}"
dinitctl setenv DBUS_SESSION_BUS_ADDRESS="${DBUS_SESSION_BUS_ADDRESS:-unix:path=$XDG_RUNTIME_DIR/bus}"

$ cat .config/dinit.d/dinit-user-env
type = scripted
command = /usr/bin/sh $HOME/bin/dinit-user-env
restart = no
after: login.target

but this doesn't work when logging in. The ssh-agent process starts with an empty value of $SSH_AUTH_SOCK.

The only method, as I mentioned earlier, that I've found to work is

$ cat .config/dinit.d/ssh-agent

type = process
env-file = dinit-user-env
command = /usr/bin/ssh-agent -D -a $SSH_AUTH_SOCK
depends-ms: login.target
log-type = buffer

where dinit-user-env is

SSH_AUTH_SOCK=/run/user/1000/ssh-agent.socket

If I try to use $(id -u) or $XDG_RUNTIME_DIR in this file, it doesn't work as expected.

Can I write a wrapper script or perhaps use a script somehow to import environment variables into the dinit user environment such that any user service I write can resolve those variables without me needing the env-file option? I guess I could write a script that uses dinitctl setenv commands and then starts user services with dinitctl start but then that defeats the point of having dinit as a user service manager.

[davmac314]

What is the equivalent of /etc/dinit/environment for dinit when it's started as a user service manager?

There isn't one, unless dinit is started with -e <file>. See the dinit man page.

but this doesn't work when logging in. The ssh-agent process starts with an empty value of $SSH_AUTH_SOCK.

What you describe is expected behaviour. From the dinit-service man page:

   Variable substitution occurs when the service is loaded.  Therefore, it
   is typically not useful for dynamically changing service parameters
   (including command line) based on a variable that is inserted into
   dinit's environment once it is running (for example via dinitctl
   setenv).

What dinitctl setenv does affect is the environment that the service runs with. So if you wrote a wrapper script to launch ssh-agent, that would run with the expected value of SSH_AUTH_SOCK.

The better solution, at least for now, is to set the environment variables before dinit starts. You can possibly do that via the pam_env PAM module.

[ayushnix]

So the choices right now are either one of the following if I want something better than env-file:

• modify the dinit backend script used by turnstile to add -e <file>
• use a wrapper script (rather than dinit) to manage ssh-agent and other software that need an env var
• use PAM

none of which seem ideal to me at the moment.

[ayushnix]

Using env-file seems preferable compared to the other choices.

[davmac314]

I believe XDG_RUNTIME_DIR is set by turnstile so you shouldn't need to set it in your script. Then a reasonable question is: can SSH_AUTH_SOCK and DBUS_SESSION_BUS_ADDRESS really be set before dinit is launched?

• If so, how? - that is how you can set them yourself.
• If not - don't use them. Eg change your ssh-agent command to: command = /usr/bin/ssh-agent -D -a $XDG_RUNTIME_DIR/ssh-agent.socket

[ayushnix]

Thanks, using XDG_RUNTIME_DIR in the command seems better than using env-file.

Although it would be nice to have something like environment.d. I'm not sure if the dinit backend in turnstile should attempt to set a default value for -e <file> because that seems like a nice method to set other environment variables as well.