114 lines
3.4 KiB
Nix
114 lines
3.4 KiB
Nix
{
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impermanence,
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config,
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lib,
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inTester,
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...
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}:
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with lib;
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{
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imports = [
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"${impermanence}/nixos.nix"
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./user-impermanence.nix
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];
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options = {
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environment.impermanence.enable = mkEnableOption "Enables impermanence";
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};
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config = mkMerge [
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{
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environment.impermanence.enable = mkDefault (!config.boot.isContainer && !inTester);
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}
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(mkIf config.environment.impermanence.enable {
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boot.initrd.systemd.services.rootfs-cleanup = {
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description = "Clean file system root";
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wantedBy = [
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"initrd.target"
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];
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after = [
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"initrd-root-device.target"
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];
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before = [
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"sysroot.mount"
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];
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unitConfig.DefaultDependencies = "no";
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serviceConfig.Type = "oneshot";
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script = ''
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# workaround for machines without working rtc battery
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# The time may not yet be correctly set, so wait until it is
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if [[ $(date '+%s') -lt 1730469314 ]]; then
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sleep 30 # this should hopefully be enough
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fi
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mkdir /btrfs_tmp
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mount ${config.fileSystems."/".device} -t btrfs /btrfs_tmp
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if [[ -e /btrfs_tmp/root ]]; then
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mkdir -p /btrfs_tmp/old_roots
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timestamp=$(date --date="@$(stat -c %X /btrfs_tmp/root)" "+%Y-%m-%d_%H:%M:%S")
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mv /btrfs_tmp/root "/btrfs_tmp/old_roots/$timestamp"
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fi
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delete_subvolume_recursively() {
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IFS=$'\n'
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for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
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delete_subvolume_recursively "/btrfs_tmp/$i"
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done
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btrfs subvolume delete "$1" || rm -rf "$1"
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}
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for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -atime +30); do
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delete_subvolume_recursively "$i"
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done
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btrfs subvolume create /btrfs_tmp/root
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umount /btrfs_tmp
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'';
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};
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assertions = [
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{
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assertion = hasAttr "/" config.fileSystems;
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message = "To use impermanence, you need to define a root volume";
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}
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{
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assertion =
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if hasAttr "/" config.fileSystems then config.fileSystems."/".fsType == "btrfs" else false;
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message = "rootfs must be btrfs";
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}
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{
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assertion =
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if hasAttr "/" config.fileSystems then
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any (t: t == "subvol=root" || t == "subvol=/root") config.fileSystems."/".options
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else
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false;
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message = "rootfs must mount subvolume root";
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}
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];
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fileSystems."/persistent" = {
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device =
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if hasAttr "/" config.fileSystems then mkDefault config.fileSystems."/".device else "/dev/null";
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fsType = "btrfs";
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options = [ "subvol=persistent" ];
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neededForBoot = true;
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};
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environment.persistence."/persistent" = {
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enable = true;
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hideMounts = true;
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directories = [
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"/var/log"
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"/var/lib/nixos"
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"/var/cache"
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];
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files = [
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"/etc/ssh/ssh_host_ecdsa_key"
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"/etc/ssh/ssh_host_ecdsa_key.pub"
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"/etc/ssh/ssh_host_ed25519_key"
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"/etc/ssh/ssh_host_ed25519_key.pub"
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"/etc/ssh/ssh_host_rsa_key"
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"/etc/ssh/ssh_host_rsa_key.pub"
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];
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};
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systemd.tmpfiles.rules = [
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"d /persistent/var/cache 1777 root root 7d -"
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];
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})
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];
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}
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