commit cba277a1dcd82e872c75794e4b593dea84520575 · pyrox.dev/nixpkgs

+101 -84

nixos/modules/tasks/filesystems/overlayfs.nix

···

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       { config, lib, pkgs, utils, ... }:

     

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       let

     

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         # The scripted initrd contains some magic to add the prefix to the

     

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         # paths just in time, so we don't add it here.

     

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         sysrootPrefix = fs:

     

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           if config.boot.initrd.systemd.enable && fs.overlay.useStage1BaseDirectories && (utils.fsNeededForBoot fs) then

     

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             "/sysroot"

     

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           else

     

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             "";

     

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         # Returns a service that creates the required directories before the mount is

     

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         # created.

     

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         preMountService = _name: fs:

     

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           let

     

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             prefix = sysrootPrefix fs;

     

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···

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             upperdir = prefix + fs.overlay.upperdir;

     

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             workdir = prefix + fs.overlay.workdir;

     

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           in

     

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           lib.mkIf (fs.overlay.upperdir != null)

     

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             {

     

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               "rw-${escapedMountpoint}" = {

     

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                 requiredBy = [ mountUnit ];

     

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                 before = [ mountUnit ];

     

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                 unitConfig = {

     

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                   DefaultDependencies = false;

     

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                   RequiresMountsFor = "${upperdir} ${workdir}";

     

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                 };

     

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                 serviceConfig = {

     

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                   Type = "oneshot";

     

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                   ExecStart = "${pkgs.coreutils}/bin/mkdir -p -m 0755 ${upperdir} ${workdir}";

     

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                 };

     

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               };

     

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             };

     

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         overlayOpts = { config, ... }: {

     

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           options.overlay = {

     

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             lowerdir = lib.mkOption {

     

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               type = with lib.types; nullOr (nonEmptyListOf (either str pathInStore));

     

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               default = null;

     

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               description = ''

     

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                 The list of path(s) to the lowerdir(s).

     

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                 To create a writable overlay, you MUST provide an `upperdir` and a

     

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                 `workdir`.

     

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                 You can create a read-only overlay when you provide multiple (at

     

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                 least 2!) lowerdirs and neither an `upperdir` nor a `workdir`.

     

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               '';

     

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             };

     

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             upperdir = lib.mkOption {

     

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               type = lib.types.nullOr lib.types.str;

     

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               default = null;

     

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               description = ''

     

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                 The path to the upperdir.

     

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                 If this is null, a read-only overlay is created using the lowerdir.

     

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                 If the filesystem is `neededForBoot`, this will be prefixed with `/sysroot`,

     

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                 unless `useStage1BaseDirectories` is set to `true`.

     

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                 If you set this to some value you MUST also set `workdir`.

     

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               '';

     

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             };

     

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             workdir = lib.mkOption {

     

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               type = lib.types.nullOr lib.types.str;

     

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               default = null;

     

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               description = ''

     

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                 The path to the workdir.

     

       78
        
       

     

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                 If the filesystem is `neededForBoot`, this will be prefixed with `/sysroot`,

     

       80
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                 unless `useStage1BaseDirectories` is set to `true`.

     

       81
        
       

     

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                 This MUST be set if you set `upperdir`.

     

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               '';

     

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             };

     

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             useStage1BaseDirectories = lib.mkOption {

     

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               type = lib.types.bool;

     

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               default = true;

     

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               description = ''

     

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                 If enabled, `lowerdir`, `upperdir` and `workdir` will be prefixed with `/sysroot`.

     

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                 Disabling this can be useful to create an overlay over directories which aren't on the real root.

     

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                 Disabling this does not work with the scripted (i.e. non-systemd) initrd.

     

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               '';

     

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             };

     

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           };

     

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           config = lib.mkIf (config.overlay.lowerdir != null) {

     

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             fsType = "overlay";

     

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             device = lib.mkDefault "overlay";

     

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             depends = map (x: "${x}") (config.overlay.lowerdir ++ lib.optionals (config.overlay.upperdir != null) [

     

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               config.overlay.upperdir

     

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               config.overlay.workdir

     

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             ]);

     

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             options =

     

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               let

     

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                 prefix = sysrootPrefix config;

     

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                 lowerdir = map (s: prefix + s) config.overlay.lowerdir;

     

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                 upperdir = prefix + config.overlay.upperdir;

     

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                 workdir = prefix + config.overlay.workdir;

     

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               in

     

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               [

     

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                 "lowerdir=${lib.concatStringsSep ":" lowerdir}"

     

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               ] ++ lib.optionals (config.overlay.upperdir != null) [

     

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                 "upperdir=${upperdir}"

     

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                 "workdir=${workdir}"

     

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               ];

     

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           };

     

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         };

     

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       in

     

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       {

···

       1
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       {

     

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         config,

     

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         lib,

     

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         pkgs,

     

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         utils,

     

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         ...

     

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       }:

     

       8
        
       

     

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       let

     

       10
        
         # The scripted initrd contains some magic to add the prefix to the

     

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         # paths just in time, so we don't add it here.

     

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         sysrootPrefix =

     

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           fs:

     

       14
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           if

     

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             config.boot.initrd.systemd.enable

     

       16
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             && fs.overlay.useStage1BaseDirectories

     

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             && (utils.fsNeededForBoot fs)

     

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           then

     

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             "/sysroot"

     

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           else

     

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             "";

     

       22
        
       

     

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         # Returns a service that creates the required directories before the mount is

     

       24
        
         # created.

     

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         preMountService =

     

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           _name: fs:

     

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           let

     

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             prefix = sysrootPrefix fs;

     

       29
        
       

     
···

       33
        
             upperdir = prefix + fs.overlay.upperdir;

     

       34
        
             workdir = prefix + fs.overlay.workdir;

     

       35
        
           in

     

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           lib.mkIf (fs.overlay.upperdir != null) {

     

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             "rw-${escapedMountpoint}" = {

     

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               requiredBy = [ mountUnit ];

     

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               before = [ mountUnit ];

     

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               unitConfig = {

     

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                 DefaultDependencies = false;

     

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                 RequiresMountsFor = "${upperdir} ${workdir}";

     

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               };

     

       44
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               serviceConfig = {

     

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                 Type = "oneshot";

     

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                 ExecStart = "${pkgs.coreutils}/bin/mkdir -p -m 0755 ${upperdir} ${workdir}";

     

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               };

     

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             };

     

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           };

     

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         overlayOpts =

     

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           {

     

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             config,

     

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             ...

     

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           }:

     

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           {

     

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             options.overlay = {

     

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               lowerdir = lib.mkOption {

     

       59
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                 type = with lib.types; nullOr (nonEmptyListOf (either str pathInStore));

     

       60
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                 default = null;

     

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                 description = ''

     

       62
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                   The list of path(s) to the lowerdir(s).

     

       63
        
       

     

       64
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                   To create a writable overlay, you MUST provide an `upperdir` and a

     

       65
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                   `workdir`.

     

       66
        
       

     

       67
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                   You can create a read-only overlay when you provide multiple (at

     

       68
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                   least 2!) lowerdirs and neither an `upperdir` nor a `workdir`.

     

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                 '';

     

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               };

     

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       71
        
       

     

       72
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               upperdir = lib.mkOption {

     

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                 type = lib.types.nullOr lib.types.str;

     

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                 default = null;

     

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                 description = ''

     

       76
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                   The path to the upperdir.

     

       77
        
       

     

       78
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                   If this is null, a read-only overlay is created using the lowerdir.

     

       79
       +
       

     

       80
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                   If the filesystem is `neededForBoot`, this will be prefixed with `/sysroot`,

     

       81
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                   unless `useStage1BaseDirectories` is set to `true`.

     

       82
        
       

     

       83
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                   If you set this to some value you MUST also set `workdir`.

     

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                 '';

     

       85
       +
               };

     

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       86
        
       

     

       87
       +
               workdir = lib.mkOption {

     

       88
       +
                 type = lib.types.nullOr lib.types.str;

     

       89
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                 default = null;

     

       90
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                 description = ''

     

       91
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                   The path to the workdir.

     

       92
        
       

     

       93
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                   If the filesystem is `neededForBoot`, this will be prefixed with `/sysroot`,

     

       94
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                   unless `useStage1BaseDirectories` is set to `true`.

     

       95
        
       

     

       96
       +
                   This MUST be set if you set `upperdir`.

     

       97
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                 '';

     

       98
       +
               };

     

       99
        
       

     

       100
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               useStage1BaseDirectories = lib.mkOption {

     

       101
       +
                 type = lib.types.bool;

     

       102
       +
                 default = true;

     

       103
       +
                 description = ''

     

       104
       +
                   If enabled, `lowerdir`, `upperdir` and `workdir` will be prefixed with `/sysroot`.

     

       105
        
       

     

       106
       +
                   Disabling this can be useful to create an overlay over directories which aren't on the real root.

     

       0
        
       
     

       107
        
       

     

       108
       +
                   Disabling this does not work with the scripted (i.e. non-systemd) initrd.

     

       109
       +
                 '';

     

       110
       +
               };

     

       111
        
             };

     

       112
        
       

     

       113
       +
             config = lib.mkIf (config.overlay.lowerdir != null) {

     

       114
       +
               fsType = "overlay";

     

       115
       +
               device = lib.mkDefault "overlay";

     

       116
       +
               depends = map (x: "${x}") (

     

       117
       +
                 config.overlay.lowerdir

     

       118
       +
                 ++ lib.optionals (config.overlay.upperdir != null) [

     

       119
       +
                   config.overlay.upperdir

     

       120
       +
                   config.overlay.workdir

     

       121
       +
                 ]

     

       122
       +
               );

     

       123
        
       

     

       124
       +
               options =

     

       125
       +
                 let

     

       126
       +
                   prefix = sysrootPrefix config;

     

       127
        
       

     

       128
       +
                   lowerdir = map (s: prefix + s) config.overlay.lowerdir;

     

       129
       +
                   upperdir = prefix + config.overlay.upperdir;

     

       130
       +
                   workdir = prefix + config.overlay.workdir;

     

       131
       +
                 in

     

       132
       +
                 [

     

       133
       +
                   "lowerdir=${lib.concatStringsSep ":" lowerdir}"

     

       134
       +
                 ]

     

       135
       +
                 ++ lib.optionals (config.overlay.upperdir != null) [

     

       136
       +
                   "upperdir=${upperdir}"

     

       137
       +
                   "workdir=${workdir}"

     

       138
       +
                 ];

     

       139
        
             };

     

       140
        
           };

     

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       141
        
       in

     

       142
        
       

     

       143
        
       {