99a6c7d547
The persistence block at core/system/impermanence.nix:75 read
`users.nomarchy = { directories = [...]; }` — the username was a
literal, not a reference. For any user not literally named "nomarchy"
the block was silently inert and ~/.ssh, ~/.gnupg, ~/.local/share/keyrings,
Documents, Downloads, Pictures, Videos, Projects were wiped on every boot.
Adds `nomarchy.system.impermanence.user` (str, default "nomarchy") and
uses it via `users.${cfg.user}`. The installer now writes the chosen
username alongside `enable` and `mainLuksName` so impermanence installs
with non-default usernames are correct out of the box.
docs/OPTIONS.md: fixes the wrong path on the impermanence row
(documented `impermanence.enable`, real option is
`nomarchy.system.impermanence.enable`) and adds entries for
`mainLuksName` and `user`.
Found during Pillar 8 audit of core/system modules.
102 lines
3.0 KiB
Nix
102 lines
3.0 KiB
Nix
{ config, lib, pkgs, inputs, ... }:
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let
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cfg = config.nomarchy.system.impermanence;
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in
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{
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imports = [
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inputs.impermanence.nixosModules.impermanence
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];
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options.nomarchy.system.impermanence = {
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enable = lib.mkEnableOption "Erase Your Darlings (Impermanence) root wipe on boot";
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# The disko layout names the main LUKS mapping `crypted` on single-disk
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# installs and `crypted_main` on multi-disk installs (see
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# installer/disko-config.nix: `mainLuksName`). The rollback hook must
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# mount the right device, otherwise initrd fails on every boot and the
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# @ → root-blank snapshot is never restored.
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mainLuksName = lib.mkOption {
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type = lib.types.str;
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default = "crypted";
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description = ''
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Name of the /dev/mapper entry holding the BTRFS root. Set to
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"crypted_main" on multi-disk installs to match the disko layout.
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'';
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};
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user = lib.mkOption {
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type = lib.types.str;
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default = "nomarchy";
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description = ''
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Primary user whose home subset (.ssh, .gnupg, keyrings, common
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directories) survives the rootfs wipe. Must match the user
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created via `users.users.<name>` — otherwise the persistence
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block is silently inert and the user's home directory is wiped
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on every boot. The installer writes this for you.
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'';
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};
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};
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config = lib.mkIf cfg.enable {
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# 1. The Rollback Script: Runs in initrd before filesystems are mounted
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boot.initrd.postDeviceCommands = lib.mkAfter ''
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mkdir -p /btrfs_tmp
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mount -o subvol=/ /dev/mapper/${cfg.mainLuksName} /btrfs_tmp
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if [[ -e /btrfs_tmp/@ ]]; then
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mkdir -p /btrfs_tmp/old_roots
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timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/@)" "+%Y-%m-%-d_%H:%M:%S")
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mv /btrfs_tmp/@ "/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"
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}
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for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +30); do
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delete_subvolume_recursively "$i"
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done
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btrfs subvolume snapshot /btrfs_tmp/root-blank /btrfs_tmp/@
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umount /btrfs_tmp
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'';
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# 2. Persistence Configuration: What survives the wipe
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environment.persistence."/persist" = {
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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/lib/systemd/coredump"
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"/var/lib/NetworkManager"
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"/etc/NetworkManager/system-connections"
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"/var/lib/bluetooth"
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"/var/lib/fprint"
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"/etc/nixos"
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"/etc/ssh"
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];
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files = [
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"/etc/machine-id"
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"/etc/supergfxd.conf"
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];
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users.${cfg.user} = {
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directories = [
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".ssh"
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".gnupg"
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".local/share/keyrings"
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"Documents"
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"Downloads"
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"Pictures"
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"Videos"
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"Projects"
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];
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};
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};
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};
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}
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