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Files
flake-nixinator/system/modules/impermanence/default.nix

380 lines
14 KiB
Nix

{
config,
lib,
mylib,
username,
pkgs,
...
}: let
inherit (config.modules) impermanence;
in {
options.modules.impermanence = import ./options.nix {inherit lib mylib;};
config = let
# NOTE: Setting user/group/mode only has an effect if the
# directory is created by impermanence!
m777 = "u=rwx,g=rwx,o=rwx";
m755 = "u=rwx,g=rx,o=rx";
m711 = "u=rwx,g=x,o=x";
m700 = "u=rwx,g=,o=";
m644 = "u=rw,g=r,o=r";
m600 = "u=rw,g=,o=";
m444 = "u=r,g=r,o=r";
mkDir = user: directory: mode: {
inherit directory mode;
user = config.users.users.${user}.name;
group = config.users.users.${user}.group;
};
mkFile = user: file: mode: {
inherit file;
# This doesn't make much sense to set generally, e.g. when
# linking multiple files to ~/.config (they all have the same parent directory)
# parentDirectory = {
# inherit mode;
# user = config.users.users.${user}.name;
# group = config.users.users.${user}.group;
# };
};
mkRDir = mkDir "root";
mkRFile = mkFile "root";
mkUDir = mkDir "${username}";
mkUFile = mkFile "${username}";
# TODO: sth. like this, make options for configdirs/sharedirs/statedirs/homedirs
# populate options from respective modules, not here...
# mkConfigDirs = dirs:
# dirs
# |> builtins.map (dir: ".config/${dir}")
# |> builtins.map mkUDir # NOTE: mkUDir has wrong arg order
in
lib.mkIf impermanence.enable {
# TODO: Create options to allow host-specific impermanence setup
# inside the respective modules
environment.persistence."/persist" = {
hideMounts = false; # Sets x-gvfs-hide option
files = [
(mkRFile "/etc/adjtime" m644)
(mkRFile "/etc/machine-id" m444)
];
directories = [
(mkRDir "/etc/NetworkManager" m755)
(mkRDir "/etc/secureboot" m755)
(mkRDir "/etc/ssh" m755)
# https://github.com/nix-community/impermanence/issues/253
(mkRDir "/usr/systemd-placeholder" m755)
(mkRDir "/var/cache/restic-backups-synology" m755)
(mkRDir "/var/db/sudo" m711)
(mkRDir "/var/lib/bluetooth" m755) # m700
(mkRDir "/var/lib/btrfs" m755)
(mkRDir "/var/lib/containers" m755)
(mkRDir "/var/lib/flatpak" m755)
(mkRDir "/var/lib/libvirt" m755)
(mkRDir "/var/lib/NetworkManager" m755)
(mkRDir "/var/lib/nixos" m755)
(mkRDir "/var/lib/sbctl" m755)
(mkRDir "/var/lib/systemd" m755)
(mkRDir "/var/tmp" m777)
];
users.${username} = {
files = [
# NOTE: Don't put files generated/linked by HM here (they're already managed)
# TODO: Specifying files here (e.g. .config/QtProject.conf) doesn't seem to work
# They won't get mounted, also they can't be unmounted (because they're not mounted),
# which leads to /home not being unmounted correctly during shutdown...
];
directories = [
# Home directory
(mkUDir "Downloads" m755)
(mkUDir "Documents" m755)
(mkUDir "GitRepos" m755)
(mkUDir "NixFlake" m755)
(mkUDir "Notes" m755)
(mkUDir "Pictures" m755)
(mkUDir "Projects" m755)
(mkUDir "Public" m755)
# (mkUDir "Unity" m755)
(mkUDir "Videos" m755)
# Secrets
(mkUDir ".gnupg" m755) # m600
(mkUDir ".secrets" m755) # m644
(mkUDir ".ssh" m755) # m644
# The shit some applications add to ~/ without asking
# (mkUDir ".android" m755) # Unity
# (mkUDir ".gradle" m755) # Unity
# (mkUDir ".java" m755) # Unity/Rider
(mkUDir ".mozilla/firefox" m755) # TODO: Remove this someday
(mkUDir ".mozilla/native-messaging-hosts" m755)
(mkUDir ".nix-package-search" m755)
# (mkUDir ".nv" m755) # Unity
(mkUDir ".ollama" m755)
# (mkUDir ".plastic4" m755) # Unity
(mkUDir ".var/app" m755)
(mkUDir ".vim/undo" m755)
(mkUDir ".zotero" m755)
# Cache that's actually useful
(mkUDir ".cache/fish/generated_completions" m755)
(mkUDir ".cache/nix-index" m755)
(mkUDir ".cache/nix-search-tv" m755)
(mkUDir ".cache/nvim" m755)
# Config
# (mkUDir ".config/.android" m755) # Unity
(mkUDir ".config/beets" m755)
(mkUDir ".config/blender" m755)
(mkUDir ".config/chromium" m755) # TODO: Remove this someday
(mkUDir ".config/Ferdium" m755)
(mkUDir ".config/fish/completions" m755)
(mkUDir ".config/impermanence" m755)
(mkUDir ".config/JetBrains" m755)
(mkUDir ".config/kdeconnect" m755)
(mkUDir ".config/keepassxc" m755)
(mkUDir ".config/Msty" m755)
(mkUDir ".config/Nextcloud" m755)
(mkUDir ".config/obsidian" m755)
(mkUDir ".config/obs-studio" m755)
(mkUDir ".config/Signal" m755)
# (mkUDir ".config/singularitygroup-hotreload" m755) # Unity
(mkUDir ".config/tidal-hifi" m755)
(mkUDir ".config/tidal_dl_ng" m755)
# (mkUDir ".config/unity3d" m755) # Unity
# (mkUDir ".config/unityhub" m755) # Unity
(mkUDir ".config/vlc" m755)
(mkUDir ".config/Zeal" m755)
# Share
(mkUDir ".local/share/direnv" m755)
(mkUDir ".local/share/docker" m755)
(mkUDir ".local/share/fish" m755)
(mkUDir ".local/share/flatpak" m755)
(mkUDir ".local/share/JetBrains" m755) # Unity
(mkUDir ".local/share/hyprland" m755)
(mkUDir ".local/share/keyrings" m755) # m700
(mkUDir ".local/share/LRCGET" m755)
(mkUDir ".local/share/mime" m755)
(mkUDir ".local/share/net.lrclib.lrcget" m755)
(mkUDir ".local/share/nix" m755)
(mkUDir ".local/share/nvim" m755)
(mkUDir ".local/share/qutebrowser" m755)
(mkUDir ".local/share/systemd" m755)
# (mkUDir ".local/share/unity3d" m755) # Unity
(mkUDir ".local/share/zoxide" m755)
# State
(mkUDir ".local/state/astal/notifd" m755)
(mkUDir ".local/state/home-manager/gc-roots" m755) # nix-flatpak stores its state there
(mkUDir ".local/state/lazygit" m755)
(mkUDir ".local/state/nix" m755)
(mkUDir ".local/state/nvim" m755)
(mkUDir ".local/state/wireplumber" m755)
];
};
};
# Add some helper scripts to identify files that might need persisting
environment.systemPackages = let
base = {
"root" = "/";
"home" = "/home/${username}";
};
ignore = {
"root" = "/home/${username}/.config/impermanence/fdignore-root";
"home" = "/home/${username}/.config/impermanence/fdignore-home";
};
move = {
"root" = "/persist/$(dirname {})";
"home" = "/persist/home/${username}/$(dirname {})";
};
mkHeader = "Press CTRL-R to reload, CTRL-M to move, CTRL-I to ignore file";
mkPreview = mode: "bat --color=always --theme=ansi --style=numbers --line-range=:100 ${base.${mode}}/{}";
mkReload = mode: "sudo fd --one-file-system --type f --hidden --base-directory ${base.${mode}} --ignore-file ${ignore.${mode}}";
mkIgnore = mode: "echo '{}' >> ${ignore.${mode}}";
mkMove = mode: "sudo mkdir -p ${move.${mode}} && sudo mv {} ${move.${mode}}";
mkScript = mode: ''
sudo ${mkReload mode} | \
sudo fzf \
--header "${mkHeader}" \
--preview "${mkPreview mode}" \
--bind "ctrl-r:reload:(${mkReload mode})" \
--bind "ctrl-i:execute:(${mkIgnore mode})" \
--bind "ctrl-m:execute:(${mkMove mode})"
'';
newroot = pkgs.writeShellScriptBin "newroot" (mkScript "root");
newhome = pkgs.writeShellScriptBin "newhome" (mkScript "home");
in [
newroot
newhome
];
# NOTE: This is REQUIRED for HM activation!
# Otherwise the home directory won't be writable!
systemd.services."impermanence-fix-home-ownership" = let
homeDir = "/home/${username}";
homeUser =
builtins.toString
config.users.users.${username}.uid;
homeGroup =
builtins.toString
config.users.groups.${config.users.users.${username}.group}.gid;
in {
description = "Fix impermanent home ownership";
wantedBy = ["home-manager-${username}.service"];
before = ["home-manager-${username}.service"];
after = ["home.mount"];
partOf = ["home.mount"];
serviceConfig.Type = "oneshot";
script = ''
# Don't chown if NFS shares are already mounted.
# This can happen outside of regular booting (e.g. nixos-rebuild switch),
# so we don't return an error.
# NOTE: Use || true as NixOS sets the damn -e, otherwise this unit fails on boot!
nfs_mounts=$(grep ' nfs4 ' /proc/mounts || true)
if [[ -n "$nfs_mounts" ]]; then
echo "NFS shares are mounted into the home directory, aborting:"
echo "$nfs_mounts"
exit 0
else
echo "No NFS shares are mounted into the home directory, continuing..."
fi
if [[ -d ${homeDir} ]]; then
chown -R ${homeUser}:${homeGroup} ${homeDir}
echo "Set ownership for ${homeDir} to ${homeUser}:${homeGroup}"
else
echo "ERROR: Home ${homeDir} does not exist!"
exit 1
fi
'';
};
# Because we have a LUKS encrypted drive
# we use a systemd service to cleanup the volumes
boot.initrd.systemd = {
enable = true;
services.impermanence-btrfs-cleanup = let
backupDuration = "7"; # Days
mountDir = "/btrfs_tmp";
persistDir = "${mountDir}/persist";
in {
description = "Clean impermanent btrfs subvolumes";
wantedBy = ["initrd.target"];
after = ["systemd-cryptsetup@crypted.service"];
before = ["sysroot.mount"];
unitConfig.DefaultDependencies = "no";
serviceConfig.Type = "oneshot";
# NOTE: If any single line of this script fails
# the entire system might be bricked.
# NixOS automatically sets "-e", so if unlucky,
# the subvolumes won'e exist for mounting...
script = let
mvSubvolToPersist = subvol: ''
if [[ -e ${mountDir}/${subvol} ]]; then
mkdir -p ${persistDir}/old_${subvol}s
timestamp=$(date --date="@$(stat -c %Y ${mountDir}/${subvol})" "+%Y-%m-%-d_%H:%M:%S")
mv ${mountDir}/${subvol} "${persistDir}/old_${subvol}s/$timestamp"
# Make the backup mutable (in case it is not, e.g. /var/empty)
# chattr -R -i -f "${persistDir}/old_${subvol}s/$timestamp"
echo "Backed up previous ${subvol} subvolume to ${persistDir}/old_${subvol}s/$timestamp"
fi
'';
mkNewSubvol = subvol: ''
if [[ ! -e ${mountDir}/${subvol} ]]; then
btrfs subvolume create ${mountDir}/${subvol}
echo "Created new subvolume ${mountDir}/${subvol}"
else
echo "Failed to move ${mountDir}/${subvol} (${mountDir}/${subvol} still exists), not creating new subvolume..."
fi
'';
# TODO: This fails and bricks the system
deleteOldBackups = subvol: ''
for old_${subvol} in $(find ${persistDir}/old_${subvol}s/ -maxdepth 1 -mtime +${backupDuration}); do
delete_subvolume_recursively "$old_${subvol}"
done
'';
in ''
# This dir will be created in the initrd ramdisk
mkdir -p ${mountDir}
# We mount the root subvolume. Because we're using a flat btrfs layout,
# "/" contains the subfolders (-volumes) home, log, nix, persist, root, swap, ...
mount -o subvol=/ /dev/mapper/crypted ${mountDir}
# Check if the persist dir exists so we can move stuff to it
if [[ ! -e ${persistDir} ]]; then
echo "${persistDir} doesn't exist, aborting..."
umount ${mountDir}
rmdir ${mountDir}
exit 0
fi
# Move root subvolume to backup location
${mvSubvolToPersist "root"}
# Move home subvolume to backup location
${mvSubvolToPersist "home"}
# Create new root subvolume
${mkNewSubvol "root"}
# Create new home subvolume
${mkNewSubvol "home"}
# TODO: Did this removal of old backups always brick the system?
# Delete a backed up subvolume
# delete_subvolume_recursively() {
# IFS=$'\n'
# # https://github.com/nix-community/impermanence/issues/258#issuecomment-2733383737
# # If we accidentally end up with a file or directory under old_roots,
# # the code will enumerate all subvolumes under the main volume.
# # We don't want to remove everything under true main volume. Only
# # proceed if this path is a btrfs subvolume (inode=256).
# if [ $(stat -c %i "$1") -ne 256 ]; then return; fi
# for subvol in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
# delete_subvolume_recursively "${persistDir}/$subvol"
# done
# btrfs subvolume delete "$1"
# echo "Deleted old subvolume $1"
# }
# Delete old root backups
# $ {deleteOldBackups "root"}
# Delete old home backups
# $ {deleteOldBackups "home"}
umount ${mountDir}
rmdir ${mountDir}
'';
};
};
};
}