nixos-init: init at 0.1.0 (#433154) (e7fa9ff1) · Commits · nix / nixpkgs

doc/release-notes/rl-2511.section.md

+1 −0

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		@@ -9,6 +9,7 @@
		and newer series. However, embedded chips without LSX (Loongson SIMD eXtension), such as 2K0300 SoC, are not
		supported. `pkgsCross.loongarch64-linux-embedded` can be used to build software and systems for these platforms.
		- The official Nix formatter `nixfmt` is now stable and available as `pkgs.nixfmt`, deprecating the temporary `pkgs.nixfmt-rfc-style` attribute. The classic `nixfmt` will stay available for some more time as `pkgs.nixfmt-classic`.
		- Added `nixos-init`, a Rust-based bashless initialization system for systemd initrd. This allows to build NixOS systems without any interpreter. Enable via `system.nixos-init.enable = true;`.

		## Backward Incompatibilities {#sec-nixpkgs-release-25.11-incompatibilities}

nixos/modules/module-list.nix

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		@@ -1803,6 +1803,7 @@
		./system/activation/activatable-system.nix
		./system/activation/activation-script.nix
		./system/activation/bootspec.nix
		./system/activation/nixos-init.nix
		./system/activation/pre-switch-check.nix
		./system/activation/specialisation.nix
		./system/activation/switchable-system.nix

nixos/modules/system/activation/nixos-init.nix

0 → 100644

+31 −0

Original line number	Diff line number	Diff line
		{
		config,
		lib,
		pkgs,
		...
		}:

		let
		cfg = config.system.nixos-init;
		in
		{
		options.system.nixos-init = {
		enable = lib.mkEnableOption ''
		nixos-init, a system for bashless initialization.

		This doesn't use any `activationScripts`. Anything set in these options is
		a no-op here.
		'';

		package = lib.mkPackageOption pkgs "nixos-init" { };
		};

		config = lib.mkIf cfg.enable {
		assertions = [
		{
		assertion = config.boot.initrd.systemd.enable;
		message = "nixos-init can only be used with systemd initrd";
		}
		];
		};
		}

nixos/modules/system/activation/top-level.nix

+5 −2

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		@@ -14,12 +14,15 @@ let
		${
		if config.boot.initrd.enable && config.boot.initrd.systemd.enable then
		''
		cp ${config.system.build.bootStage2} $out/prepare-root
		substituteInPlace $out/prepare-root --subst-var-by systemConfig $out
		# This must not be a symlink or the abs_path of the grub builder for the tests
		# will resolve the symlink and we end up with a path that doesn't point to a
		# system closure.
		cp "$systemd/lib/systemd/systemd" $out/init

		${lib.optionalString (!config.system.nixos-init.enable) ''
		cp ${config.system.build.bootStage2} $out/prepare-root
		substituteInPlace $out/prepare-root --subst-var-by systemConfig $out
		''}
		''
		else
		''

nixos/modules/system/boot/systemd/initrd.nix

+54 −15

Original line number	Diff line number	Diff line
		@@ -562,7 +562,12 @@ in
		"${pkgs.glibc}/lib/libnss_files.so.2"

		# Resolving sysroot symlinks without code exec
		"${pkgs.chroot-realpath}/bin/chroot-realpath"
		"${config.system.nixos-init.package}/bin/chroot-realpath"
		# Find the etc paths
		"${config.system.nixos-init.package}/bin/find-etc"
		]
		++ lib.optionals config.system.nixos-init.enable [
		"${config.system.nixos-init.package}/bin/initrd-init"
		]
		++ jobScripts
		++ map (c: builtins.removeAttrs c [ "text" ]) (builtins.attrValues cfg.contents);
		@@ -594,7 +599,7 @@ in
		) cfg.automounts
		);

		services.initrd-find-nixos-closure = {
		services.initrd-find-nixos-closure = lib.mkIf (!config.system.nixos-init.enable) {
		description = "Find NixOS closure";

		unitConfig = {
		@@ -615,7 +620,12 @@ in
		script = # bash
		''
		set -uo pipefail
		export PATH="/bin:${cfg.package.util-linux}/bin:${pkgs.chroot-realpath}/bin"
		export PATH="/bin:${
		lib.makeBinPath [
		cfg.package.util-linux
		config.system.nixos-init.package
		]
		}"

		# Figure out what closure to boot
		closure=
		@@ -670,7 +680,7 @@ in
		}
		];

		services.initrd-nixos-activation = {
		services.initrd-nixos-activation = lib.mkIf (!config.system.nixos-init.enable) {
		after = [ "initrd-switch-root.target" ];
		requiredBy = [ "initrd-switch-root.service" ];
		before = [ "initrd-switch-root.service" ];
		@@ -697,17 +707,46 @@ in
		'';
		};

		services.initrd-switch-root =
		if config.system.nixos-init.enable then
		{
		path = [
		cfg.package
		cfg.package.util-linux
		config.system.nixos-init.package
		];
		environment = {
		FIRMWARE = "${config.hardware.firmware}/lib/firmware";
		MODPROBE_BINARY = "${pkgs.kmod}/bin/modprobe";
		NIX_STORE_MOUNT_OPTS = lib.concatStringsSep "," config.boot.nixStoreMountOpts;
		}
		// lib.optionalAttrs (config.environment.usrbinenv != null) {
		ENV_BINARY = config.environment.usrbinenv;
		}
		// lib.optionalAttrs (config.environment.binsh != null) {
		SH_BINARY = config.environment.binsh;
		};
		serviceConfig = {
		ExecStart = [
		""
		"${config.system.nixos-init.package}/bin/initrd-init"
		];
		};
		}
		else
		# This will either call systemctl with the new init as the last parameter (which
		# is the case when not booting a NixOS system) or with an empty string, causing
		# systemd to bypass its verification code that checks whether the next file is a systemd
		# and using its compiled-in value
		services.initrd-switch-root.serviceConfig = {
		{
		serviceConfig = {
		EnvironmentFile = "-/etc/switch-root.conf";
		ExecStart = [
		""
		''systemctl --no-block switch-root /sysroot "''${NEW_INIT}"''
		];
		};
		};

		services.panic-on-fail = {
		wantedBy = [ "emergency.target" ];

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