diff --git a/flake.nix b/flake.nix index 7845ed0..bd88547 100644 --- a/flake.nix +++ b/flake.nix @@ -68,6 +68,10 @@ ]; hosts.nixos-laptop.modules = [ ./hosts/nixos-laptop ]; - hosts.nixos-desktop.modules = [ ./hosts/nixos-desktop ./modules/gaming ]; + hosts.nixos-desktop.modules = [ + ./hosts/nixos-desktop + ./modules/gaming + ./modules/darling-erasure.nix + ]; }; } diff --git a/modules/darling-erasure.nix b/modules/darling-erasure.nix new file mode 100644 index 0000000..e9ed79c --- /dev/null +++ b/modules/darling-erasure.nix @@ -0,0 +1,61 @@ +{ config, lib, pkgs, ... }: + +{ + environment.etc = { + nixos.source = "/persist/etc/nixos"; + "NetworkManager/system-connections".source = + "/persist/etc/NetworkManager/system-connections"; + adjtime.source = "/persist/etc/adjtime"; + NIXOS.source = "/persist/etc/NIXOS"; + machine-id.source = "/persist/etc/machine-id"; + }; + systemd.tmpfiles.rules = [ + "L /var/lib/NetworkManager/secret_key - - - - /persist/var/lib/NetworkManager/secret_key" + "L /var/lib/NetworkManager/seen-bssids - - - - /persist/var/lib/NetworkManager/seen-bssids" + "L /var/lib/NetworkManager/timestamps - - - - /persist/var/lib/NetworkManager/timestamps" + ]; + security.sudo.extraConfig = '' + # rollback results in sudo lectures after each reboot + Defaults lecture = never + ''; + + # Note `lib.mkBefore` is used instead of `lib.mkAfter` here. + boot.initrd.postDeviceCommands = pkgs.lib.mkBefore '' + mkdir -p /mnt + + # We first mount the btrfs root to /mnt + # so we can manipulate btrfs subvolumes. + mount -o subvol=/ /dev/mapper/enc /mnt + + # While we're tempted to just delete /root and create + # a new snapshot from /root-blank, /root is already + # populated at this point with a number of subvolumes, + # which makes `btrfs subvolume delete` fail. + # So, we remove them first. + # + # /root contains subvolumes: + # - /root/var/lib/portables + # - /root/var/lib/machines + # + # I suspect these are related to systemd-nspawn, but + # since I don't use it I'm not 100% sure. + # Anyhow, deleting these subvolumes hasn't resulted + # in any issues so far, except for fairly + # benign-looking errors from systemd-tmpfiles. + btrfs subvolume list -o /mnt/root | + cut -f9 -d' ' | + while read subvolume; do + echo "deleting /$subvolume subvolume..." + btrfs subvolume delete "/mnt/$subvolume" + done && + echo "deleting /root subvolume..." && + btrfs subvolume delete /mnt/root + + echo "restoring blank /root subvolume..." + btrfs subvolume snapshot /mnt/root-blank /mnt/root + + # Once we're done rolling back to a blank snapshot, + # we can unmount /mnt and continue on the boot process. + umount /mnt + ''; +}