Commit 3a6f7a60 authored by İlkecan Bozdoğan's avatar İlkecan Bozdoğan
Browse files

nixos/envfs: fix compatibility with systemd in initrd 



This module disables the activation scripts that would normally create
`/usr/bin/env` and `/bin/sh` (and their parent directories). When
systemd is used in the initrd, the absence of these directories causes
2 problems:
- During switch-root, base_filesystem_create_fd() creates an empty /usr
  directory. Later at stage2, systemd's initialize_runtime() aborts
  booting with "Refusing to run in unsupported environment where /usr/
  is not populated."
- Once /usr/bin is restored (by the fix above), base_filesystem_create_fd()
  creates a symlink /bin -> /usr/bin. systemd-fstab-generator then
  canonicalizes the /bin fstab entry through this symlink, producing a
  duplicate usr-bin.mount.

We create both /sysroot/usr/bin and /sysroot/bin via initrd tmpfiles
to prevent both issues.

Resolves NixOS#462556

Co-authored-by: default avatarLin Yinfeng <lin.yinfeng@outlook.com>
parent 73bbf0dc

nixos/modules/tasks/filesystems/envfs.nix

+34 −0
Original line number Diff line number Diff line
@@ -74,5 +74,39 @@ in 
    # We no longer need those when using envfs

    system.activationScripts.usrbinenv = lib.mkForce "";

    system.activationScripts.binsh = lib.mkForce "";



    # Disabling the activation scripts above prevents the creation of 2

    # directories, which would normally be created just before switch-root at

    # stage1. This causes problems when systemd is used in the initrd.

    #

    # This only affects fresh installations or systems using impermanence/tmpfs

    # root, where these directories don't persist from a previous activation.

    boot.initrd.systemd.tmpfiles.settings = lib.mkIf config.boot.initrd.systemd.enable {

      "50-envfs" = {

        # During switch-root, systemd's base_filesystem_create_fd() creates an

        # empty /usr. Later at stage2, systemd initialize_runtime() checks

        # dir_is_empty("/usr/"), which returns 1 for an empty but existing

        # directory causing a fatal boot failure: "Refusing to run in

        # unsupported environment where /usr/ is not populated."

        "/sysroot/usr/bin" = {

          d = {

            group = "root";

            mode = "0755";

            user = "root";

          };

        };

        # During switch-root, base_filesystem_create_fd() creates a symlink

        # /bin -> /usr/bin if /bin does not exist. systemd-fstab-generator then

        # canonicalizes the /bin fstab entry through this symlink, producing a

        # duplicate usr-bin.mount. Create /bin to avoid this behaviour.

        "/sysroot/bin" = {

          d = {

            group = "root";

            mode = "0755";

            user = "root";

          };

        };

      };

    };

  };

}

nixos/tests/all-tests.nix

+8 −1
Original line number Diff line number Diff line
@@ -518,7 +518,14 @@ in 
  enlightenment = runTest ./enlightenment.nix;

  ente = runTest ./ente;

  env = runTest ./env.nix;

  envfs = runTest ./envfs.nix;

  envfs = runTest {

    imports = [ ./envfs.nix ];

    _module.args.systemdStage1 = false;

  };

  envfs-systemd-stage-1 = runTest {

    imports = [ ./envfs.nix ];

    _module.args.systemdStage1 = true;

  };

  envoy = runTest {

    imports = [ ./envoy.nix ];

    _module.args.envoyPackage = pkgs.envoy;

nixos/tests/envfs.nix

+11 −2
Original line number Diff line number Diff line 
{ lib, pkgs, ... }:

{

  pkgs,

  systemdStage1 ? false,

  ...

}:



let

  pythonShebang = pkgs.writeScript "python-shebang" ''

    #!/usr/bin/python
@@ -12,7 +17,11 @@ let 
in

{

  name = "envfs";

  nodes.machine.services.envfs.enable = true;



  nodes.machine = {

    services.envfs.enable = true;

    boot.initrd.systemd.enable = systemdStage1;

  };



  testScript = ''

    start_all()

pkgs/by-name/en/envfs/package.nix

+1 −1
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ rustPlatform.buildRustPackage (finalAttrs: { 


  passthru = {

    tests = {

      envfs = nixosTests.envfs;

      inherit (nixosTests) envfs envfs-systemd-stage-1;

    };



    updateScript = nix-update-script { };