added dependency to systemd

[Mikilio]

Description of changes

Fix for issue #39140

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[chkno]

This bakes the path to systemd into nixos-enter at nixos-enter's build time. I'm worried that the path to system might change between nixos-enter's build time and its run time -- for example, if the user updates channels in the install environment.

Instead of changing PATH and finding systemd-tmpfiles with a PATH lookp, consider specifying the full path to systemd-tmpfiles as $system/sw/bin/systemd-tmpfiles . This follows the convention used elsewhere in nixos-enter, which includes the ability to set $system via the --system flag.

Also, it would be great to have a test that could have caught this. I appear to have somehow neglected to submit the tests linked in #39140 (comment) (oops!), but they would not have caught this problem because the nixos-installer has a PATH that will find a systemd-tmpfiles in the chroot. It's the users trying to install from environments like Kimsufi's rescue environment that were exposed to this error. But setting up a new installer test from a wierd but realistic environment is ~1000x more work than just making this fix, so don't let that block merge of this PR.

Thanks for fixing this!

[Mikilio]

This is my first pull request to this repo, so I'm sorry if I'm not familiar with common practices here:
Do you want me to revert my changes and substitute systemd-tmpfiles with a full path instead? Or has this already been done?

[chkno]

Fantastic! Welcome!

Concretely, I mean that this change would be a better way to fix this problem than the changes this PR is currently proposing.

Mechanically, I meant to suggest that you change this PR to propose that change instead, by force-pushing https://github.com/Mikilio/nixpkgs to be a single commit that makes that change. One way to do that would be to git reset --hard HEAD^, make that change, commit, and force-push.

Alternatively, if you prefer, I could propose that change as a new PR.

(I introduced this bug in #80769 . Thank you for identifying the problem and helping get it fixed.)

[Mikilio]

Ok! Since I agree with your points I'll change my PR. Thanks for the advice!

[chkno]

Great!

Next, among other things, that "Fits CONTRIBUTING.md." checkbox in the PR template is meant to encourage good, uniform commit messages. So please skim that, look at the commit messages of some other commits in that place, change your commit message to follow those conventions (concretely: such as with git commit --amend), and force push again.

And thanks for bearing with the get-to-know-the-project-conventions first-PR back-and-forth. :)

[Mikilio]

Thank you for the guidance!

[ncfavier]

This change looks good so I'm going to merge now, but I'm curious why the chosen route was to make nixos-enter create its own /tmp, instead of simply fixing TMPDIR in nixos-install? By that point we've already created a temporary directory under the mountpoint, so TMPDIR=${TMPDIR#"$mountPoint"} nixos-enter ... should suffice?

Calling systemd-tmpfiles in the nixos-enter environment also has the annoying side-effect that it prints a bunch of red warnings like

/etc/tmpfiles.d/systemd.conf:23: Failed to replace specifiers in '/run/log/journal/%m': No such file or directory

because /etc/machine-id does not exist in the mounted root.

EDIT: I see now that creating /tmp in nixos-enter is needed for nix-build to work.

[github-actions]

Successfully created backport PR #208607 for release-22.05.

[github-actions]

Successfully created backport PR #208608 for release-22.11.

[github-actions]

Git push to origin failed for release-22.05 with exitcode 1

[github-actions]

Git push to origin failed for release-22.11 with exitcode 1