forked from mirrors/nixpkgs
7cdc4dd5d1
initrd: Opt-in bare bones systemd-based initrd
415 lines
15 KiB
Nix
415 lines
15 KiB
Nix
{ config, lib, pkgs, utils, ... }:
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with lib;
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with utils;
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let
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addCheckDesc = desc: elemType: check: types.addCheck elemType check
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// { description = "${elemType.description} (with check: ${desc})"; };
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isNonEmpty = s: (builtins.match "[ \t\n]*" s) == null;
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nonEmptyStr = addCheckDesc "non-empty" types.str isNonEmpty;
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fileSystems' = toposort fsBefore (attrValues config.fileSystems);
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fileSystems = if fileSystems' ? result
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then # use topologically sorted fileSystems everywhere
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fileSystems'.result
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else # the assertion below will catch this,
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# but we fall back to the original order
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# anyway so that other modules could check
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# their assertions too
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(attrValues config.fileSystems);
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specialFSTypes = [ "proc" "sysfs" "tmpfs" "ramfs" "devtmpfs" "devpts" ];
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nonEmptyWithoutTrailingSlash = addCheckDesc "non-empty without trailing slash" types.str
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(s: isNonEmpty s && (builtins.match ".+/" s) == null);
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coreFileSystemOpts = { name, config, ... }: {
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options = {
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mountPoint = mkOption {
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example = "/mnt/usb";
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type = nonEmptyWithoutTrailingSlash;
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description = "Location of the mounted the file system.";
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};
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device = mkOption {
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default = null;
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example = "/dev/sda";
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type = types.nullOr nonEmptyStr;
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description = "Location of the device.";
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};
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fsType = mkOption {
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default = "auto";
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example = "ext3";
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type = nonEmptyStr;
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description = "Type of the file system.";
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};
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options = mkOption {
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default = [ "defaults" ];
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example = [ "data=journal" ];
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description = "Options used to mount the file system.";
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type = types.listOf nonEmptyStr;
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};
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depends = mkOption {
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default = [ ];
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example = [ "/persist" ];
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type = types.listOf nonEmptyWithoutTrailingSlash;
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description = ''
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List of paths that should be mounted before this one. This filesystem's
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<option>device</option> and <option>mountPoint</option> are always
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checked and do not need to be included explicitly. If a path is added
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to this list, any other filesystem whose mount point is a parent of
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the path will be mounted before this filesystem. The paths do not need
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to actually be the <option>mountPoint</option> of some other filesystem.
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'';
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};
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};
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config = {
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mountPoint = mkDefault name;
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device = mkIf (elem config.fsType specialFSTypes) (mkDefault config.fsType);
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};
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};
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fileSystemOpts = { config, ... }: {
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options = {
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label = mkOption {
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default = null;
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example = "root-partition";
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type = types.nullOr nonEmptyStr;
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description = "Label of the device (if any).";
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};
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autoFormat = mkOption {
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default = false;
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type = types.bool;
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description = ''
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If the device does not currently contain a filesystem (as
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determined by <command>blkid</command>, then automatically
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format it with the filesystem type specified in
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<option>fsType</option>. Use with caution.
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'';
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};
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formatOptions = mkOption {
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default = "";
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type = types.str;
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description = ''
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If <option>autoFormat</option> option is set specifies
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extra options passed to mkfs.
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'';
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};
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autoResize = mkOption {
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default = false;
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type = types.bool;
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description = ''
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If set, the filesystem is grown to its maximum size before
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being mounted. (This is typically the size of the containing
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partition.) This is currently only supported for ext2/3/4
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filesystems that are mounted during early boot.
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'';
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};
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noCheck = mkOption {
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default = false;
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type = types.bool;
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description = "Disable running fsck on this filesystem.";
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};
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};
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config = let
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defaultFormatOptions =
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# -F needed to allow bare block device without partitions
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if (builtins.substring 0 3 config.fsType) == "ext" then "-F"
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# -q needed for non-interactive operations
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else if config.fsType == "jfs" then "-q"
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# (same here)
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else if config.fsType == "reiserfs" then "-q"
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else null;
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in {
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options = mkIf config.autoResize [ "x-nixos.autoresize" ];
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formatOptions = mkIf (defaultFormatOptions != null) (mkDefault defaultFormatOptions);
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};
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};
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# Makes sequence of `specialMount device mountPoint options fsType` commands.
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# `systemMount` should be defined in the sourcing script.
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makeSpecialMounts = mounts:
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pkgs.writeText "mounts.sh" (concatMapStringsSep "\n" (mount: ''
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specialMount "${mount.device}" "${mount.mountPoint}" "${concatStringsSep "," mount.options}" "${mount.fsType}"
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'') mounts);
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in
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{
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###### interface
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options = {
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fileSystems = mkOption {
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default = {};
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example = literalExpression ''
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{
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"/".device = "/dev/hda1";
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"/data" = {
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device = "/dev/hda2";
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fsType = "ext3";
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options = [ "data=journal" ];
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};
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"/bigdisk".label = "bigdisk";
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}
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'';
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type = types.attrsOf (types.submodule [coreFileSystemOpts fileSystemOpts]);
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description = ''
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The file systems to be mounted. It must include an entry for
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the root directory (<literal>mountPoint = "/"</literal>). Each
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entry in the list is an attribute set with the following fields:
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<literal>mountPoint</literal>, <literal>device</literal>,
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<literal>fsType</literal> (a file system type recognised by
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<command>mount</command>; defaults to
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<literal>"auto"</literal>), and <literal>options</literal>
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(the mount options passed to <command>mount</command> using the
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<option>-o</option> flag; defaults to <literal>[ "defaults" ]</literal>).
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Instead of specifying <literal>device</literal>, you can also
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specify a volume label (<literal>label</literal>) for file
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systems that support it, such as ext2/ext3 (see <command>mke2fs
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-L</command>).
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'';
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};
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system.fsPackages = mkOption {
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internal = true;
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default = [ ];
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description = "Packages supplying file system mounters and checkers.";
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};
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boot.supportedFilesystems = mkOption {
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default = [ ];
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example = [ "btrfs" ];
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type = types.listOf types.str;
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description = "Names of supported filesystem types.";
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};
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boot.specialFileSystems = mkOption {
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default = {};
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type = types.attrsOf (types.submodule coreFileSystemOpts);
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internal = true;
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description = ''
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Special filesystems that are mounted very early during boot.
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'';
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};
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boot.devSize = mkOption {
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default = "5%";
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example = "32m";
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type = types.str;
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description = ''
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Size limit for the /dev tmpfs. Look at mount(8), tmpfs size option,
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for the accepted syntax.
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'';
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};
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boot.devShmSize = mkOption {
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default = "50%";
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example = "256m";
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type = types.str;
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description = ''
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Size limit for the /dev/shm tmpfs. Look at mount(8), tmpfs size option,
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for the accepted syntax.
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'';
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};
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boot.runSize = mkOption {
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default = "25%";
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example = "256m";
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type = types.str;
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description = ''
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Size limit for the /run tmpfs. Look at mount(8), tmpfs size option,
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for the accepted syntax.
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'';
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};
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};
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###### implementation
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config = {
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assertions = let
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ls = sep: concatMapStringsSep sep (x: x.mountPoint);
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notAutoResizable = fs: fs.autoResize && !(hasPrefix "ext" fs.fsType || fs.fsType == "f2fs");
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in [
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{ assertion = ! (fileSystems' ? cycle);
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message = "The ‘fileSystems’ option can't be topologically sorted: mountpoint dependency path ${ls " -> " fileSystems'.cycle} loops to ${ls ", " fileSystems'.loops}";
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}
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{ assertion = ! (any notAutoResizable fileSystems);
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message = let
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fs = head (filter notAutoResizable fileSystems);
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in
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"Mountpoint '${fs.mountPoint}': 'autoResize = true' is not supported for 'fsType = \"${fs.fsType}\"':${if fs.fsType == "auto" then " fsType has to be explicitly set and" else ""} only the ext filesystems and f2fs support it.";
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}
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];
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# Export for use in other modules
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system.build.fileSystems = fileSystems;
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system.build.earlyMountScript = makeSpecialMounts (toposort fsBefore (attrValues config.boot.specialFileSystems)).result;
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boot.supportedFilesystems = map (fs: fs.fsType) fileSystems;
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# Add the mount helpers to the system path so that `mount' can find them.
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system.fsPackages = [ pkgs.dosfstools ];
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environment.systemPackages = with pkgs; [ fuse3 fuse ] ++ config.system.fsPackages;
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environment.etc.fstab.text =
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let
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fsToSkipCheck = [ "none" "bindfs" "btrfs" "zfs" "tmpfs" "nfs" "vboxsf" "glusterfs" "apfs" ];
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skipCheck = fs: fs.noCheck || fs.device == "none" || builtins.elem fs.fsType fsToSkipCheck;
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# https://wiki.archlinux.org/index.php/fstab#Filepath_spaces
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escape = string: builtins.replaceStrings [ " " "\t" ] [ "\\040" "\\011" ] string;
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swapOptions = sw: concatStringsSep "," (
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sw.options
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++ optional (sw.priority != null) "pri=${toString sw.priority}"
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++ optional (sw.discardPolicy != null) "discard${optionalString (sw.discardPolicy != "both") "=${toString sw.discardPolicy}"}"
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);
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in ''
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# This is a generated file. Do not edit!
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#
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# To make changes, edit the fileSystems and swapDevices NixOS options
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# in your /etc/nixos/configuration.nix file.
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#
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# <file system> <mount point> <type> <options> <dump> <pass>
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# Filesystems.
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${concatMapStrings (fs:
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(if fs.device != null then escape fs.device
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else if fs.label != null then "/dev/disk/by-label/${escape fs.label}"
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else throw "No device specified for mount point ‘${fs.mountPoint}’.")
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+ " " + escape fs.mountPoint
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+ " " + fs.fsType
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+ " " + builtins.concatStringsSep "," fs.options
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+ " 0"
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+ " " + (if skipCheck fs then "0" else
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if fs.mountPoint == "/" then "1" else "2")
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+ "\n"
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) fileSystems}
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# Swap devices.
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${flip concatMapStrings config.swapDevices (sw:
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"${sw.realDevice} none swap ${swapOptions sw}\n"
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)}
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'';
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# Provide a target that pulls in all filesystems.
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systemd.targets.fs =
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{ description = "All File Systems";
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wants = [ "local-fs.target" "remote-fs.target" ];
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};
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systemd.services =
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# Emit systemd services to format requested filesystems.
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let
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formatDevice = fs:
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let
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mountPoint' = "${escapeSystemdPath fs.mountPoint}.mount";
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device' = escapeSystemdPath fs.device;
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device'' = "${device'}.device";
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in nameValuePair "mkfs-${device'}"
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{ description = "Initialisation of Filesystem ${fs.device}";
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wantedBy = [ mountPoint' ];
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before = [ mountPoint' "systemd-fsck@${device'}.service" ];
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requires = [ device'' ];
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after = [ device'' ];
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path = [ pkgs.util-linux ] ++ config.system.fsPackages;
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script =
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''
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if ! [ -e "${fs.device}" ]; then exit 1; fi
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# FIXME: this is scary. The test could be more robust.
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type=$(blkid -p -s TYPE -o value "${fs.device}" || true)
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if [ -z "$type" ]; then
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echo "creating ${fs.fsType} filesystem on ${fs.device}..."
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mkfs.${fs.fsType} ${fs.formatOptions} "${fs.device}"
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fi
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'';
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unitConfig.RequiresMountsFor = [ "${dirOf fs.device}" ];
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unitConfig.DefaultDependencies = false; # needed to prevent a cycle
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serviceConfig.Type = "oneshot";
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};
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in listToAttrs (map formatDevice (filter (fs: fs.autoFormat && !(utils.fsNeededForBoot fs)) fileSystems)) // {
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# Mount /sys/fs/pstore for evacuating panic logs and crashdumps from persistent storage onto the disk using systemd-pstore.
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# This cannot be done with the other special filesystems because the pstore module (which creates the mount point) is not loaded then.
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"mount-pstore" = {
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serviceConfig = {
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Type = "oneshot";
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# skip on kernels without the pstore module
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ExecCondition = "${pkgs.kmod}/bin/modprobe -b pstore";
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ExecStart = pkgs.writeShellScript "mount-pstore.sh" ''
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set -eu
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# if the pstore module is builtin it will have mounted the persistent store automatically. it may also be already mounted for other reasons.
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${pkgs.util-linux}/bin/mountpoint -q /sys/fs/pstore || ${pkgs.util-linux}/bin/mount -t pstore -o nosuid,noexec,nodev pstore /sys/fs/pstore
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# wait up to 1.5 seconds for the backend to be registered and the files to appear. a systemd path unit cannot detect this happening; and succeeding after a restart would not start dependent units.
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TRIES=15
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while [ "$(cat /sys/module/pstore/parameters/backend)" = "(null)" ]; do
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if (( $TRIES )); then
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sleep 0.1
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TRIES=$((TRIES-1))
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else
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echo "Persistent Storage backend was not registered in time." >&2
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break
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fi
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done
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'';
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RemainAfterExit = true;
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};
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unitConfig = {
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ConditionVirtualization = "!container";
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DefaultDependencies = false; # needed to prevent a cycle
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};
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before = [ "systemd-pstore.service" ];
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wantedBy = [ "systemd-pstore.service" ];
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};
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};
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systemd.tmpfiles.rules = [
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"d /run/keys 0750 root ${toString config.ids.gids.keys}"
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"z /run/keys 0750 root ${toString config.ids.gids.keys}"
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];
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# Sync mount options with systemd's src/core/mount-setup.c: mount_table.
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boot.specialFileSystems = {
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"/proc" = { fsType = "proc"; options = [ "nosuid" "noexec" "nodev" ]; };
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"/run" = { fsType = "tmpfs"; options = [ "nosuid" "nodev" "strictatime" "mode=755" "size=${config.boot.runSize}" ]; };
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"/dev" = { fsType = "devtmpfs"; options = [ "nosuid" "strictatime" "mode=755" "size=${config.boot.devSize}" ]; };
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"/dev/shm" = { fsType = "tmpfs"; options = [ "nosuid" "nodev" "strictatime" "mode=1777" "size=${config.boot.devShmSize}" ]; };
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"/dev/pts" = { fsType = "devpts"; options = [ "nosuid" "noexec" "mode=620" "ptmxmode=0666" "gid=${toString config.ids.gids.tty}" ]; };
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# To hold secrets that shouldn't be written to disk
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"/run/keys" = { fsType = "ramfs"; options = [ "nosuid" "nodev" "mode=750" ]; };
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} // optionalAttrs (!config.boot.isContainer) {
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# systemd-nspawn populates /sys by itself, and remounting it causes all
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# kinds of weird issues (most noticeably, waiting for host disk device
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# nodes).
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"/sys" = { fsType = "sysfs"; options = [ "nosuid" "noexec" "nodev" ]; };
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};
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};
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}
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