nixpkgs/nixos/modules/system/boot/systemd/initrd.nix
r-vdp 9258f57625
systemd: add a name option to all systemd units
This allows us to set things like dependencies in a way that we can
catch typos at eval time.
So instead of
```nix
systemd.services.foo.wants = [ "bar.service" ];
```
we can write
```nix
systemd.services.foo.wants = [ config.systemd.services.bar.name ];
```
which will throw an error if no such service has been defined.

Not all cases can be done like this (eg template services), but in a lot
of cases this will allow to avoid typos.

There is a matching option on the unit option
(`systemd.units."foo.service".name`) as well.
2024-04-15 11:32:45 +02:00

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{ lib, options, config, utils, pkgs, ... }:
with lib;
let
inherit (utils) systemdUtils escapeSystemdPath;
inherit (systemdUtils.lib)
generateUnits
pathToUnit
serviceToUnit
sliceToUnit
socketToUnit
targetToUnit
timerToUnit
mountToUnit
automountToUnit;
cfg = config.boot.initrd.systemd;
upstreamUnits = [
"basic.target"
"ctrl-alt-del.target"
"debug-shell.service"
"emergency.service"
"emergency.target"
"final.target"
"halt.target"
"initrd-cleanup.service"
"initrd-fs.target"
"initrd-parse-etc.service"
"initrd-root-device.target"
"initrd-root-fs.target"
"initrd-switch-root.service"
"initrd-switch-root.target"
"initrd.target"
"kexec.target"
"kmod-static-nodes.service"
"local-fs-pre.target"
"local-fs.target"
"multi-user.target"
"paths.target"
"poweroff.target"
"reboot.target"
"rescue.service"
"rescue.target"
"rpcbind.target"
"shutdown.target"
"sigpwr.target"
"slices.target"
"sockets.target"
"swap.target"
"sysinit.target"
"sys-kernel-config.mount"
"syslog.socket"
"systemd-ask-password-console.path"
"systemd-ask-password-console.service"
"systemd-fsck@.service"
"systemd-halt.service"
"systemd-hibernate-resume.service"
"systemd-journald-audit.socket"
"systemd-journald-dev-log.socket"
"systemd-journald.service"
"systemd-journald.socket"
"systemd-kexec.service"
"systemd-modules-load.service"
"systemd-poweroff.service"
"systemd-reboot.service"
"systemd-sysctl.service"
"systemd-tmpfiles-setup-dev.service"
"systemd-tmpfiles-setup.service"
"timers.target"
"umount.target"
"systemd-bsod.service"
] ++ cfg.additionalUpstreamUnits;
upstreamWants = [
"sysinit.target.wants"
];
enabledUpstreamUnits = filter (n: ! elem n cfg.suppressedUnits) upstreamUnits;
enabledUnits = filterAttrs (n: v: ! elem n cfg.suppressedUnits) cfg.units;
jobScripts = concatLists (mapAttrsToList (_: unit: unit.jobScripts or []) (filterAttrs (_: v: v.enable) cfg.services));
stage1Units = generateUnits {
type = "initrd";
units = enabledUnits;
upstreamUnits = enabledUpstreamUnits;
inherit upstreamWants;
inherit (cfg) packages package;
};
kernel-name = config.boot.kernelPackages.kernel.name or "kernel";
# Determine the set of modules that we need to mount the root FS.
modulesClosure = pkgs.makeModulesClosure {
rootModules = config.boot.initrd.availableKernelModules ++ config.boot.initrd.kernelModules;
kernel = config.system.modulesTree;
firmware = config.hardware.firmware;
allowMissing = false;
};
initrdBinEnv = pkgs.buildEnv {
name = "initrd-bin-env";
paths = map getBin cfg.initrdBin;
pathsToLink = ["/bin" "/sbin"];
postBuild = concatStringsSep "\n" (mapAttrsToList (n: v: "ln -sf '${v}' $out/bin/'${n}'") cfg.extraBin);
};
initialRamdisk = pkgs.makeInitrdNG {
name = "initrd-${kernel-name}";
inherit (config.boot.initrd) compressor compressorArgs prepend;
inherit (cfg) strip;
contents = map (path: { object = path; symlink = ""; }) (subtractLists cfg.suppressedStorePaths cfg.storePaths)
++ mapAttrsToList (_: v: { object = v.source; symlink = v.target; }) (filterAttrs (_: v: v.enable) cfg.contents);
};
in {
options.boot.initrd.systemd = {
enable = mkEnableOption "systemd in initrd" // {
description = ''
Whether to enable systemd in initrd. The unit options such as
{option}`boot.initrd.systemd.services` are the same as their
stage 2 counterparts such as {option}`systemd.services`,
except that `restartTriggers` and `reloadTriggers` are not
supported.
'';
};
package = lib.mkOption {
type = lib.types.package;
default = config.systemd.package;
defaultText = lib.literalExpression "config.systemd.package";
description = ''
The systemd package to use.
'';
};
extraConfig = mkOption {
default = "";
type = types.lines;
example = "DefaultLimitCORE=infinity";
description = ''
Extra config options for systemd. See systemd-system.conf(5) man page
for available options.
'';
};
managerEnvironment = mkOption {
type = with types; attrsOf (nullOr (oneOf [ str path package ]));
default = {};
example = { SYSTEMD_LOG_LEVEL = "debug"; };
description = ''
Environment variables of PID 1. These variables are
*not* passed to started units.
'';
};
contents = mkOption {
description = "Set of files that have to be linked into the initrd";
example = literalExpression ''
{
"/etc/hostname".text = "mymachine";
}
'';
default = {};
type = utils.systemdUtils.types.initrdContents;
};
storePaths = mkOption {
description = ''
Store paths to copy into the initrd as well.
'';
type = with types; listOf (oneOf [ singleLineStr package ]);
default = [];
};
strip = mkOption {
description = ''
Whether to completely strip executables and libraries copied to the initramfs.
Setting this to false may save on the order of 30MiB on the
machine building the system (by avoiding a binutils
reference), at the cost of ~1MiB of initramfs size. This puts
this option firmly in the territory of micro-optimisation.
'';
type = types.bool;
default = true;
};
extraBin = mkOption {
description = ''
Tools to add to /bin
'';
example = literalExpression ''
{
umount = ''${pkgs.util-linux}/bin/umount;
}
'';
type = types.attrsOf types.path;
default = {};
};
suppressedStorePaths = mkOption {
description = ''
Store paths specified in the storePaths option that
should not be copied.
'';
type = types.listOf types.singleLineStr;
default = [];
};
root = lib.mkOption {
type = lib.types.enum [ "fstab" "gpt-auto" ];
default = "fstab";
example = "gpt-auto";
description = ''
Controls how systemd will interpret the root FS in initrd. See
{manpage}`kernel-command-line(7)`. NixOS currently does not
allow specifying the root file system itself this
way. Instead, the `fstab` value is used in order to interpret
the root file system specified with the `fileSystems` option.
'';
};
emergencyAccess = mkOption {
type = with types; oneOf [ bool (nullOr (passwdEntry str)) ];
description = ''
Set to true for unauthenticated emergency access, and false for
no emergency access.
Can also be set to a hashed super user password to allow
authenticated access to the emergency mode.
'';
default = false;
};
initrdBin = mkOption {
type = types.listOf types.package;
default = [];
description = ''
Packages to include in /bin for the stage 1 emergency shell.
'';
};
additionalUpstreamUnits = mkOption {
default = [ ];
type = types.listOf types.str;
example = [ "debug-shell.service" "systemd-quotacheck.service" ];
description = ''
Additional units shipped with systemd that shall be enabled.
'';
};
suppressedUnits = mkOption {
default = [ ];
type = types.listOf types.str;
example = [ "systemd-backlight@.service" ];
description = ''
A list of units to skip when generating system systemd configuration directory. This has
priority over upstream units, {option}`boot.initrd.systemd.units`, and
{option}`boot.initrd.systemd.additionalUpstreamUnits`. The main purpose of this is to
prevent a upstream systemd unit from being added to the initrd with any modifications made to it
by other NixOS modules.
'';
};
units = mkOption {
description = "Definition of systemd units.";
default = {};
visible = "shallow";
type = systemdUtils.types.units;
};
packages = mkOption {
default = [];
type = types.listOf types.package;
example = literalExpression "[ pkgs.systemd-cryptsetup-generator ]";
description = "Packages providing systemd units and hooks.";
};
targets = mkOption {
default = {};
visible = "shallow";
type = systemdUtils.types.initrdTargets;
description = "Definition of systemd target units.";
};
services = mkOption {
default = {};
type = systemdUtils.types.initrdServices;
visible = "shallow";
description = "Definition of systemd service units.";
};
sockets = mkOption {
default = {};
type = systemdUtils.types.initrdSockets;
visible = "shallow";
description = "Definition of systemd socket units.";
};
timers = mkOption {
default = {};
type = systemdUtils.types.initrdTimers;
visible = "shallow";
description = "Definition of systemd timer units.";
};
paths = mkOption {
default = {};
type = systemdUtils.types.initrdPaths;
visible = "shallow";
description = "Definition of systemd path units.";
};
mounts = mkOption {
default = [];
type = systemdUtils.types.initrdMounts;
visible = "shallow";
description = ''
Definition of systemd mount units.
This is a list instead of an attrSet, because systemd mandates the names to be derived from
the 'where' attribute.
'';
};
automounts = mkOption {
default = [];
type = systemdUtils.types.automounts;
visible = "shallow";
description = ''
Definition of systemd automount units.
This is a list instead of an attrSet, because systemd mandates the names to be derived from
the 'where' attribute.
'';
};
slices = mkOption {
default = {};
type = systemdUtils.types.slices;
visible = "shallow";
description = "Definition of slice configurations.";
};
enableTpm2 = mkOption {
default = true;
type = types.bool;
description = ''
Whether to enable TPM2 support in the initrd.
'';
};
};
config = mkIf (config.boot.initrd.enable && cfg.enable) {
assertions = [
{
assertion = cfg.root == "fstab" -> any (fs: fs.mountPoint == "/") (builtins.attrValues config.fileSystems);
message = "The fileSystems option does not specify your root file system.";
}
] ++ map (name: {
assertion = lib.attrByPath name (throw "impossible") config.boot.initrd == "";
message = ''
systemd stage 1 does not support 'boot.initrd.${lib.concatStringsSep "." name}'. Please
convert it to analogous systemd units in 'boot.initrd.systemd'.
Definitions:
${lib.concatMapStringsSep "\n" ({ file, ... }: " - ${file}") (lib.attrByPath name (throw "impossible") options.boot.initrd).definitionsWithLocations}
'';
}) [
[ "preFailCommands" ]
[ "preDeviceCommands" ]
[ "preLVMCommands" ]
[ "postDeviceCommands" ]
[ "postResumeCommands" ]
[ "postMountCommands" ]
[ "extraUdevRulesCommands" ]
[ "extraUtilsCommands" ]
[ "extraUtilsCommandsTest" ]
[ "network" "postCommands" ]
];
system.build = { inherit initialRamdisk; };
boot.initrd.availableKernelModules = [
# systemd needs this for some features
"autofs"
# systemd-cryptenroll
] ++ lib.optional cfg.enableTpm2 "tpm-tis"
++ lib.optional (cfg.enableTpm2 && !(pkgs.stdenv.hostPlatform.isRiscV64 || pkgs.stdenv.hostPlatform.isArmv7)) "tpm-crb"
++ lib.optional cfg.package.withEfi "efivarfs";
boot.kernelParams = [
"root=${config.boot.initrd.systemd.root}"
] ++ lib.optional (config.boot.resumeDevice != "") "resume=${config.boot.resumeDevice}"
# `systemd` mounts root in initrd as read-only unless "rw" is on the kernel command line.
# For NixOS activation to succeed, we need to have root writable in initrd.
++ lib.optional (config.boot.initrd.systemd.root == "gpt-auto") "rw";
boot.initrd.systemd = {
# bashInteractive is easier to use and also required by debug-shell.service
initrdBin = [pkgs.bashInteractive pkgs.coreutils cfg.package.kmod cfg.package];
extraBin = {
less = "${pkgs.less}/bin/less";
mount = "${cfg.package.util-linux}/bin/mount";
umount = "${cfg.package.util-linux}/bin/umount";
fsck = "${cfg.package.util-linux}/bin/fsck";
};
managerEnvironment.PATH = "/bin:/sbin";
contents = {
"/tmp/.keep".text = "systemd requires the /tmp mount point in the initrd cpio archive";
"/init".source = "${cfg.package}/lib/systemd/systemd";
"/etc/systemd/system".source = stage1Units;
"/etc/systemd/system.conf".text = ''
[Manager]
DefaultEnvironment=PATH=/bin:/sbin
${cfg.extraConfig}
ManagerEnvironment=${lib.concatStringsSep " " (lib.mapAttrsToList (n: v: "${n}=${lib.escapeShellArg v}") cfg.managerEnvironment)}
'';
"/lib".source = "${modulesClosure}/lib";
"/etc/modules-load.d/nixos.conf".text = concatStringsSep "\n" config.boot.initrd.kernelModules;
# We can use either ! or * to lock the root account in the
# console, but some software like OpenSSH won't even allow you
# to log in with an SSH key if you use ! so we use * instead
"/etc/shadow".text = "root:${if isBool cfg.emergencyAccess then optionalString (!cfg.emergencyAccess) "*" else cfg.emergencyAccess}:::::::";
"/bin".source = "${initrdBinEnv}/bin";
"/sbin".source = "${initrdBinEnv}/sbin";
"/etc/sysctl.d/nixos.conf".text = "kernel.modprobe = /sbin/modprobe";
"/etc/modprobe.d/systemd.conf".source = "${cfg.package}/lib/modprobe.d/systemd.conf";
"/etc/modprobe.d/ubuntu.conf".source = pkgs.runCommand "initrd-kmod-blacklist-ubuntu" { } ''
${pkgs.buildPackages.perl}/bin/perl -0pe 's/## file: iwlwifi.conf(.+?)##/##/s;' $src > $out
'';
"/etc/modprobe.d/debian.conf".source = pkgs.kmod-debian-aliases;
"/etc/os-release".source = config.boot.initrd.osRelease;
"/etc/initrd-release".source = config.boot.initrd.osRelease;
} // optionalAttrs (config.environment.etc ? "modprobe.d/nixos.conf") {
"/etc/modprobe.d/nixos.conf".source = config.environment.etc."modprobe.d/nixos.conf".source;
};
storePaths = [
# systemd tooling
"${cfg.package}/lib/systemd/systemd-executor"
"${cfg.package}/lib/systemd/systemd-fsck"
"${cfg.package}/lib/systemd/systemd-hibernate-resume"
"${cfg.package}/lib/systemd/systemd-journald"
"${cfg.package}/lib/systemd/systemd-makefs"
"${cfg.package}/lib/systemd/systemd-modules-load"
"${cfg.package}/lib/systemd/systemd-remount-fs"
"${cfg.package}/lib/systemd/systemd-shutdown"
"${cfg.package}/lib/systemd/systemd-sulogin-shell"
"${cfg.package}/lib/systemd/systemd-sysctl"
"${cfg.package}/lib/systemd/systemd-bsod"
# generators
"${cfg.package}/lib/systemd/system-generators/systemd-debug-generator"
"${cfg.package}/lib/systemd/system-generators/systemd-fstab-generator"
"${cfg.package}/lib/systemd/system-generators/systemd-gpt-auto-generator"
"${cfg.package}/lib/systemd/system-generators/systemd-hibernate-resume-generator"
"${cfg.package}/lib/systemd/system-generators/systemd-run-generator"
# utilities needed by systemd
"${cfg.package.util-linux}/bin/mount"
"${cfg.package.util-linux}/bin/umount"
"${cfg.package.util-linux}/bin/sulogin"
# required for script services
"${pkgs.runtimeShell}"
# so NSS can look up usernames
"${pkgs.glibc}/lib/libnss_files.so.2"
] ++ optionals (cfg.package.withCryptsetup && cfg.enableTpm2) [
# tpm2 support
"${cfg.package}/lib/cryptsetup/libcryptsetup-token-systemd-tpm2.so"
pkgs.tpm2-tss
] ++ optionals cfg.package.withCryptsetup [
# fido2 support
"${cfg.package}/lib/cryptsetup/libcryptsetup-token-systemd-fido2.so"
"${pkgs.libfido2}/lib/libfido2.so.1"
] ++ jobScripts;
targets.initrd.aliases = ["default.target"];
units =
mapAttrs' (n: v: nameValuePair "${n}.path" (pathToUnit v)) cfg.paths
// mapAttrs' (n: v: nameValuePair "${n}.service" (serviceToUnit v)) cfg.services
// mapAttrs' (n: v: nameValuePair "${n}.slice" (sliceToUnit v)) cfg.slices
// mapAttrs' (n: v: nameValuePair "${n}.socket" (socketToUnit v)) cfg.sockets
// mapAttrs' (n: v: nameValuePair "${n}.target" (targetToUnit v)) cfg.targets
// mapAttrs' (n: v: nameValuePair "${n}.timer" (timerToUnit v)) cfg.timers
// listToAttrs (map
(v: let n = escapeSystemdPath v.where;
in nameValuePair "${n}.mount" (mountToUnit v)) cfg.mounts)
// listToAttrs (map
(v: let n = escapeSystemdPath v.where;
in nameValuePair "${n}.automount" (automountToUnit v)) cfg.automounts);
# make sure all the /dev nodes are set up
services.systemd-tmpfiles-setup-dev.wantedBy = ["sysinit.target"];
services.initrd-nixos-activation = {
after = [ "initrd-fs.target" ];
requiredBy = [ "initrd.target" ];
unitConfig.AssertPathExists = "/etc/initrd-release";
serviceConfig.Type = "oneshot";
description = "NixOS Activation";
script = /* bash */ ''
set -uo pipefail
export PATH="/bin:${cfg.package.util-linux}/bin"
# Figure out what closure to boot
closure=
for o in $(< /proc/cmdline); do
case $o in
init=*)
IFS== read -r -a initParam <<< "$o"
closure="''${initParam[1]}"
;;
esac
done
# Sanity check
if [ -z "''${closure:-}" ]; then
echo 'No init= parameter on the kernel command line' >&2
exit 1
fi
# Resolve symlinks in the init parameter. We need this for some boot loaders
# (e.g. boot.loader.generationsDir).
closure="$(chroot /sysroot ${pkgs.coreutils}/bin/realpath "$closure")"
# Assume the directory containing the init script is the closure.
closure="$(dirname "$closure")"
# If we are not booting a NixOS closure (e.g. init=/bin/sh),
# we don't know what root to prepare so we don't do anything
if ! [ -x "/sysroot$(readlink "/sysroot$closure/prepare-root" || echo "$closure/prepare-root")" ]; then
echo "NEW_INIT=''${initParam[1]}" > /etc/switch-root.conf
echo "$closure does not look like a NixOS installation - not activating"
exit 0
fi
echo 'NEW_INIT=' > /etc/switch-root.conf
# We need to propagate /run for things like /run/booted-system
# and /run/current-system.
mkdir -p /sysroot/run
mount --bind /run /sysroot/run
# Initialize the system
export IN_NIXOS_SYSTEMD_STAGE1=true
exec chroot /sysroot $closure/prepare-root
'';
};
# This will either call systemctl with the new init as the last parameter (which
# is the case when not booting a NixOS system) or with an empty string, causing
# systemd to bypass its verification code that checks whether the next file is a systemd
# and using its compiled-in value
services.initrd-switch-root.serviceConfig = {
EnvironmentFile = "-/etc/switch-root.conf";
ExecStart = [
""
''systemctl --no-block switch-root /sysroot "''${NEW_INIT}"''
];
};
services.panic-on-fail = {
wantedBy = ["emergency.target"];
unitConfig = {
DefaultDependencies = false;
ConditionKernelCommandLine = [
"|boot.panic_on_fail"
"|stage1panic"
];
};
script = ''
echo c > /proc/sysrq-trigger
'';
serviceConfig.Type = "oneshot";
};
};
};
}