diff options
Diffstat (limited to 'nixos/lib/systemd-lib.nix')
| -rw-r--r-- | nixos/lib/systemd-lib.nix | 440 |
1 files changed, 440 insertions, 0 deletions
diff --git a/nixos/lib/systemd-lib.nix b/nixos/lib/systemd-lib.nix new file mode 100644 index 00000000000..a472d97f5cc --- /dev/null +++ b/nixos/lib/systemd-lib.nix @@ -0,0 +1,440 @@ +{ config, lib, pkgs }: + +with lib; + +let + cfg = config.systemd; + lndir = "${pkgs.buildPackages.xorg.lndir}/bin/lndir"; + systemd = cfg.package; +in rec { + + shellEscape = s: (replaceChars [ "\\" ] [ "\\\\" ] s); + + mkPathSafeName = lib.replaceChars ["@" ":" "\\" "[" "]"] ["-" "-" "-" "" ""]; + + # a type for options that take a unit name + unitNameType = types.strMatching "[a-zA-Z0-9@%:_.\\-]+[.](service|socket|device|mount|automount|swap|target|path|timer|scope|slice)"; + + makeUnit = name: unit: + if unit.enable then + pkgs.runCommand "unit-${mkPathSafeName name}" + { preferLocalBuild = true; + allowSubstitutes = false; + inherit (unit) text; + } + '' + mkdir -p $out + echo -n "$text" > $out/${shellEscape name} + '' + else + pkgs.runCommand "unit-${mkPathSafeName name}-disabled" + { preferLocalBuild = true; + allowSubstitutes = false; + } + '' + mkdir -p $out + ln -s /dev/null $out/${shellEscape name} + ''; + + boolValues = [true false "yes" "no"]; + + digits = map toString (range 0 9); + + isByteFormat = s: + let + l = reverseList (stringToCharacters s); + suffix = head l; + nums = tail l; + in elem suffix (["K" "M" "G" "T"] ++ digits) + && all (num: elem num digits) nums; + + assertByteFormat = name: group: attr: + optional (attr ? ${name} && ! isByteFormat attr.${name}) + "Systemd ${group} field `${name}' must be in byte format [0-9]+[KMGT]."; + + hexChars = stringToCharacters "0123456789abcdefABCDEF"; + + isMacAddress = s: stringLength s == 17 + && flip all (splitString ":" s) (bytes: + all (byte: elem byte hexChars) (stringToCharacters bytes) + ); + + assertMacAddress = name: group: attr: + optional (attr ? ${name} && ! isMacAddress attr.${name}) + "Systemd ${group} field `${name}' must be a valid mac address."; + + isPort = i: i >= 0 && i <= 65535; + + assertPort = name: group: attr: + optional (attr ? ${name} && ! isPort attr.${name}) + "Error on the systemd ${group} field `${name}': ${attr.name} is not a valid port number."; + + assertValueOneOf = name: values: group: attr: + optional (attr ? ${name} && !elem attr.${name} values) + "Systemd ${group} field `${name}' cannot have value `${toString attr.${name}}'."; + + assertHasField = name: group: attr: + optional (!(attr ? ${name})) + "Systemd ${group} field `${name}' must exist."; + + assertRange = name: min: max: group: attr: + optional (attr ? ${name} && !(min <= attr.${name} && max >= attr.${name})) + "Systemd ${group} field `${name}' is outside the range [${toString min},${toString max}]"; + + assertMinimum = name: min: group: attr: + optional (attr ? ${name} && attr.${name} < min) + "Systemd ${group} field `${name}' must be greater than or equal to ${toString min}"; + + assertOnlyFields = fields: group: attr: + let badFields = filter (name: ! elem name fields) (attrNames attr); in + optional (badFields != [ ]) + "Systemd ${group} has extra fields [${concatStringsSep " " badFields}]."; + + assertInt = name: group: attr: + optional (attr ? ${name} && !isInt attr.${name}) + "Systemd ${group} field `${name}' is not an integer"; + + checkUnitConfig = group: checks: attrs: let + # We're applied at the top-level type (attrsOf unitOption), so the actual + # unit options might contain attributes from mkOverride and mkIf that we need to + # convert into single values before checking them. + defs = mapAttrs (const (v: + if v._type or "" == "override" then v.content + else if v._type or "" == "if" then v.content + else v + )) attrs; + errors = concatMap (c: c group defs) checks; + in if errors == [] then true + else builtins.trace (concatStringsSep "\n" errors) false; + + toOption = x: + if x == true then "true" + else if x == false then "false" + else toString x; + + attrsToSection = as: + concatStrings (concatLists (mapAttrsToList (name: value: + map (x: '' + ${name}=${toOption x} + '') + (if isList value then value else [value])) + as)); + + generateUnits = generateUnits' true; + + generateUnits' = allowCollisions: type: units: upstreamUnits: upstreamWants: + pkgs.runCommand "${type}-units" + { preferLocalBuild = true; + allowSubstitutes = false; + } '' + mkdir -p $out + + # Copy the upstream systemd units we're interested in. + for i in ${toString upstreamUnits}; do + fn=${cfg.package}/example/systemd/${type}/$i + if ! [ -e $fn ]; then echo "missing $fn"; false; fi + if [ -L $fn ]; then + target="$(readlink "$fn")" + if [ ''${target:0:3} = ../ ]; then + ln -s "$(readlink -f "$fn")" $out/ + else + cp -pd $fn $out/ + fi + else + ln -s $fn $out/ + fi + done + + # Copy .wants links, but only those that point to units that + # we're interested in. + for i in ${toString upstreamWants}; do + fn=${cfg.package}/example/systemd/${type}/$i + if ! [ -e $fn ]; then echo "missing $fn"; false; fi + x=$out/$(basename $fn) + mkdir $x + for i in $fn/*; do + y=$x/$(basename $i) + cp -pd $i $y + if ! [ -e $y ]; then rm $y; fi + done + done + + # Symlink all units provided listed in systemd.packages. + packages="${toString cfg.packages}" + + # Filter duplicate directories + declare -A unique_packages + for k in $packages ; do unique_packages[$k]=1 ; done + + for i in ''${!unique_packages[@]}; do + for fn in $i/etc/systemd/${type}/* $i/lib/systemd/${type}/*; do + if ! [[ "$fn" =~ .wants$ ]]; then + if [[ -d "$fn" ]]; then + targetDir="$out/$(basename "$fn")" + mkdir -p "$targetDir" + ${lndir} "$fn" "$targetDir" + else + ln -s $fn $out/ + fi + fi + done + done + + # Symlink all units defined by systemd.units. If these are also + # provided by systemd or systemd.packages, then add them as + # <unit-name>.d/overrides.conf, which makes them extend the + # upstream unit. + for i in ${toString (mapAttrsToList (n: v: v.unit) units)}; do + fn=$(basename $i/*) + if [ -e $out/$fn ]; then + if [ "$(readlink -f $i/$fn)" = /dev/null ]; then + ln -sfn /dev/null $out/$fn + else + ${if allowCollisions then '' + mkdir -p $out/$fn.d + ln -s $i/$fn $out/$fn.d/overrides.conf + '' else '' + echo "Found multiple derivations configuring $fn!" + exit 1 + ''} + fi + else + ln -fs $i/$fn $out/ + fi + done + + # Create service aliases from aliases option. + ${concatStrings (mapAttrsToList (name: unit: + concatMapStrings (name2: '' + ln -sfn '${name}' $out/'${name2}' + '') unit.aliases) units)} + + # Create .wants and .requires symlinks from the wantedBy and + # requiredBy options. + ${concatStrings (mapAttrsToList (name: unit: + concatMapStrings (name2: '' + mkdir -p $out/'${name2}.wants' + ln -sfn '../${name}' $out/'${name2}.wants'/ + '') unit.wantedBy) units)} + + ${concatStrings (mapAttrsToList (name: unit: + concatMapStrings (name2: '' + mkdir -p $out/'${name2}.requires' + ln -sfn '../${name}' $out/'${name2}.requires'/ + '') unit.requiredBy) units)} + + ${optionalString (type == "system") '' + # Stupid misc. symlinks. + ln -s ${cfg.defaultUnit} $out/default.target + ln -s ${cfg.ctrlAltDelUnit} $out/ctrl-alt-del.target + ln -s rescue.target $out/kbrequest.target + + mkdir -p $out/getty.target.wants/ + ln -s ../autovt@tty1.service $out/getty.target.wants/ + + ln -s ../remote-fs.target $out/multi-user.target.wants/ + ''} + ''; # */ + + makeJobScript = name: text: + let + scriptName = replaceChars [ "\\" "@" ] [ "-" "_" ] (shellEscape name); + out = (pkgs.writeShellScriptBin scriptName '' + set -e + ${text} + '').overrideAttrs (_: { + # The derivation name is different from the script file name + # to keep the script file name short to avoid cluttering logs. + name = "unit-script-${scriptName}"; + }); + in "${out}/bin/${scriptName}"; + + unitConfig = { config, options, ... }: { + config = { + unitConfig = + optionalAttrs (config.requires != []) + { Requires = toString config.requires; } + // optionalAttrs (config.wants != []) + { Wants = toString config.wants; } + // optionalAttrs (config.after != []) + { After = toString config.after; } + // optionalAttrs (config.before != []) + { Before = toString config.before; } + // optionalAttrs (config.bindsTo != []) + { BindsTo = toString config.bindsTo; } + // optionalAttrs (config.partOf != []) + { PartOf = toString config.partOf; } + // optionalAttrs (config.conflicts != []) + { Conflicts = toString config.conflicts; } + // optionalAttrs (config.requisite != []) + { Requisite = toString config.requisite; } + // optionalAttrs (config.restartTriggers != []) + { X-Restart-Triggers = toString config.restartTriggers; } + // optionalAttrs (config.reloadTriggers != []) + { X-Reload-Triggers = toString config.reloadTriggers; } + // optionalAttrs (config.description != "") { + Description = config.description; } + // optionalAttrs (config.documentation != []) { + Documentation = toString config.documentation; } + // optionalAttrs (config.onFailure != []) { + OnFailure = toString config.onFailure; } + // optionalAttrs (options.startLimitIntervalSec.isDefined) { + StartLimitIntervalSec = toString config.startLimitIntervalSec; + } // optionalAttrs (options.startLimitBurst.isDefined) { + StartLimitBurst = toString config.startLimitBurst; + }; + }; + }; + + serviceConfig = { name, config, ... }: { + config = mkMerge + [ { # Default path for systemd services. Should be quite minimal. + path = mkAfter + [ pkgs.coreutils + pkgs.findutils + pkgs.gnugrep + pkgs.gnused + systemd + ]; + environment.PATH = "${makeBinPath config.path}:${makeSearchPathOutput "bin" "sbin" config.path}"; + } + (mkIf (config.preStart != "") + { serviceConfig.ExecStartPre = + [ (makeJobScript "${name}-pre-start" config.preStart) ]; + }) + (mkIf (config.script != "") + { serviceConfig.ExecStart = + makeJobScript "${name}-start" config.script + " " + config.scriptArgs; + }) + (mkIf (config.postStart != "") + { serviceConfig.ExecStartPost = + [ (makeJobScript "${name}-post-start" config.postStart) ]; + }) + (mkIf (config.reload != "") + { serviceConfig.ExecReload = + makeJobScript "${name}-reload" config.reload; + }) + (mkIf (config.preStop != "") + { serviceConfig.ExecStop = + makeJobScript "${name}-pre-stop" config.preStop; + }) + (mkIf (config.postStop != "") + { serviceConfig.ExecStopPost = + makeJobScript "${name}-post-stop" config.postStop; + }) + ]; + }; + + mountConfig = { config, ... }: { + config = { + mountConfig = + { What = config.what; + Where = config.where; + } // optionalAttrs (config.type != "") { + Type = config.type; + } // optionalAttrs (config.options != "") { + Options = config.options; + }; + }; + }; + + automountConfig = { config, ... }: { + config = { + automountConfig = + { Where = config.where; + }; + }; + }; + + commonUnitText = def: '' + [Unit] + ${attrsToSection def.unitConfig} + ''; + + targetToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = + '' + [Unit] + ${attrsToSection def.unitConfig} + ''; + }; + + serviceToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = commonUnitText def + + '' + [Service] + ${let env = cfg.globalEnvironment // def.environment; + in concatMapStrings (n: + let s = optionalString (env.${n} != null) + "Environment=${builtins.toJSON "${n}=${env.${n}}"}\n"; + # systemd max line length is now 1MiB + # https://github.com/systemd/systemd/commit/e6dde451a51dc5aaa7f4d98d39b8fe735f73d2af + in if stringLength s >= 1048576 then throw "The value of the environment variable ‘${n}’ in systemd service ‘${name}.service’ is too long." else s) (attrNames env)} + ${if def.reloadIfChanged then '' + X-ReloadIfChanged=true + '' else if !def.restartIfChanged then '' + X-RestartIfChanged=false + '' else ""} + ${optionalString (!def.stopIfChanged) "X-StopIfChanged=false"} + ${attrsToSection def.serviceConfig} + ''; + }; + + socketToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = commonUnitText def + + '' + [Socket] + ${attrsToSection def.socketConfig} + ${concatStringsSep "\n" (map (s: "ListenStream=${s}") def.listenStreams)} + ${concatStringsSep "\n" (map (s: "ListenDatagram=${s}") def.listenDatagrams)} + ''; + }; + + timerToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = commonUnitText def + + '' + [Timer] + ${attrsToSection def.timerConfig} + ''; + }; + + pathToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = commonUnitText def + + '' + [Path] + ${attrsToSection def.pathConfig} + ''; + }; + + mountToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = commonUnitText def + + '' + [Mount] + ${attrsToSection def.mountConfig} + ''; + }; + + automountToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = commonUnitText def + + '' + [Automount] + ${attrsToSection def.automountConfig} + ''; + }; + + sliceToUnit = name: def: + { inherit (def) aliases wantedBy requiredBy enable; + text = commonUnitText def + + '' + [Slice] + ${attrsToSection def.sliceConfig} + ''; + }; +} |