bitspire/deploy/nixos/live.nix

# bitSpire ATM Live USB Configuration
# Bootable ISO for testing on physical hardware without installing to disk.
#
# Parameterized by machineModel (passed via specialArgs from flake.nix):
#   "douro" - Bay Trail Atom, kernel 5.15 (i915 regression in newer kernels), eDP panel
#   "tejo"  - UP4000/UPBoard, default kernel 6.6, standard Intel GPU
#
# Builds with: nix build .#iso-douro  or  nix build .#iso-tejo
#
# Does NOT import hardware/upboard.nix (its fileSystems conflict with live boot).
# Instead, duplicates only the hardware-relevant kernel modules and GPU config.

{ config, lib, pkgs, pkgs-unstable, nixpkgs, machineModel ? "douro", atm-app, kioskLauncher, ... }:

let
  # Fiat code per machine model (for envTemplate display only)
  fiatCodeForModel = {
    douro = "GTQ";
    tejo = "GTQ";
    sintra = "EUR";
    batm3 = "USD";
  }.${machineModel} or "USD";

  # Minimal .env template (aiolabs/bitspire#70 remnant hygiene). Seed ONLY
  # image-baked, non-maskable values. Relay + server pubkey come from the pairing
  # SEED, operator pubkey + fee config come from LNbits over the transport — so we
  # deliberately do NOT pre-seed those keys (a present-but-empty VITE_RELAY_URL /
  # VITE_LNBITS_SERVER_PUBKEY / VITE_OPERATOR_PUBKEYS would win over the seed and
  # mask its source). VITE_SPIRE_SEED is written by the wizard / provision-atm.sh;
  # the dev-only VITE_ATM_PRIVATE_KEY fallback is omitted on purpose.
  envTemplate = pkgs.writeText "bitspire-env" ''
    VITE_BITSPIRE_MACHINE_MODEL=${machineModel}
    VITE_BITSPIRE_FIAT_CODE=${fiatCodeForModel}
    VITE_SPIRE_SEED=
    ELECTRON_FORCE_PROD=1
    DISPLAY=:0
  '';
in
{
  imports = [
    # NixOS ISO image builder (nixpkgs path passed via specialArgs from flake.nix)
    "${nixpkgs}/nixos/modules/installer/cd-dvd/iso-image.nix"
    "${nixpkgs}/nixos/modules/profiles/all-hardware.nix"

    # Reuse kiosk config (X11, openbox, users, networking)
    ./configuration.nix

    # Reuse ATM systemd service module
    ./bitspire-atm.nix
  ]
  # Sintra: share the UP Board serial hardware (validator/dispenser/printer
  # modules + udev symlinks + console=tty0) with the installed image so the
  # live ISO drives the same hardware. Safe to import here — unlike upboard.nix
  # it declares no fileSystems, so there's no live-boot mount conflict.
  ++ lib.optionals (machineModel == "sintra") [ ./hardware/upboard-serial.nix ];

  # ISO image settings
  image.fileName = "bitspire-${machineModel}-live.iso";
  isoImage = {
    makeEfiBootable = true;
    makeBiosBootable = true;
    # Apply the isohybrid MBR + GPT/ESP so the image boots when dd'd to a USB
    # stick — not just from optical media via El Torito. Without this the ISO
    # has BIOS+UEFI El Torito boot catalogs but no partition table, and picky
    # firmware (e.g. the Sintra's Aaeon UP Board) won't recognise the USB as
    # bootable. Requires makeBiosBootable (isohdpfx.bin), set above.
    makeUsbBootable = true;
    squashfsCompression = "zstd -Xcompression-level 6";
  };

  # No fileSystems override needed — iso-image.nix handles squashfs + tmpfs root.
  # We don't import hardware/upboard.nix, so there are no conflicting disk mounts.

  # Kernel: Douro Bay Trail needs 5.15 LTS (i915 eDP regression in 6.x kernels)
  boot.kernelPackages = lib.mkIf (machineModel == "douro") pkgs.linuxPackages_5_15;

  # Boot: kernel modules and parameters (model-specific)
  boot = {
    initrd.availableKernelModules = [
      "xhci_pci"
      "ahci"
      "usb_storage"
      "sd_mod"
      "sdhci_pci"
      "i915"
      "squashfs"
      "iso9660"
      "loop"
    ];

    kernelModules = [
      "kvm-intel"
      "i2c-dev"
      "spi-dev"
    ] ++ lib.optionals (machineModel == "tejo") [
      "usbserial" # USB-to-serial adapters (ttyUSB0/1 for validator/printer)
      "ftdi_sio" # FTDI USB serial (common in ATM peripherals)
      "cp210x" # CP210x USB serial (alternative adapter)
    ] ++ lib.optionals (machineModel == "batm3") [
      "cdc_acm" # USB CDC ACM for MEI BNR Advance validator
      "usbserial" # USB-to-serial for F56 dispenser adapter
      "ftdi_sio" # FTDI USB serial (common RS232 adapter)
      "cp210x" # CP210x USB serial (alternative adapter)
    ];

    kernelParams = [
      "i915.enable_psr=0"
      "quiet"
      "splash"
    ] ++ lib.optionals (machineModel == "douro") [
      # Bay Trail: preserve BIOS display init (matches working kernel 5.4 config)
      "vt.handoff=7"
    ] ++ lib.optionals (machineModel == "tejo") [
      # UP Board debug UART for serial console
      "console=ttyS4,115200n8"
      "console=tty0"
    ];
  };

  # Intel GPU support
  hardware = {
    graphics = {
      enable = true;
      extraPackages = with pkgs; [
        intel-media-driver
        libva-vdpau-driver
        libvdpau-va-gl
      ];
    };
    enableRedistributableFirmware = true;
    cpu.intel.updateMicrocode = true;
  };

  # Performance governor for responsive kiosk
  powerManagement = {
    enable = true;
    cpuFreqGovernor = "performance";
  };

  # Disable suspend/hibernate
  systemd.targets = {
    sleep.enable = false;
    suspend.enable = false;
    hibernate.enable = false;
    hybrid-sleep.enable = false;
  };

  # Enable the ATM service with live USB paths
  services.bitspire = {
    enable = true;
    appDir = "${atm-app}";
  };

  # Allow unprivileged user namespaces (Electron sandbox needs this)
  boot.kernel.sysctl."kernel.unprivileged_userns_clone" = 1;

  # Override the systemd service for live USB environment
  systemd.services.bitspire = {
    serviceConfig = {
      EnvironmentFile = lib.mkForce "/var/lib/bitspire/.env";
      # Native modules need libstdc++ on NixOS
      Environment = "LD_LIBRARY_PATH=${pkgs.stdenv.cc.cc.lib}/lib";
      # Electron needs --no-sandbox in the live/testing environment
      # --enable-logging makes renderer console.log visible in journalctl
      ExecStart = lib.mkForce "${kioskLauncher}";
      # Prevent Electron from consuming all RAM on memory-constrained ATMs
      MemoryMax = lib.mkForce "1G";
      # Disable all security hardening that conflicts with Electron
      NoNewPrivileges = lib.mkForce false;
      ProtectSystem = lib.mkForce false;
      ProtectHome = lib.mkForce false;
      PrivateTmp = lib.mkForce false;
      # Allow access to all character devices (serial ports for HAL hardware)
      DevicePolicy = lib.mkForce "auto";
      DeviceAllow = lib.mkForce [ "char-* rw" ];
    };
  };

  # Install the .env on first boot. Attrset form with deps=["users"] so the
  # chown runs AFTER the bitspire user is created. Otherwise on a fresh live
  # boot (where /var/lib/bitspire/.env doesn't exist yet) the chown runs in the
  # default activation order — before `users` — and fails with
  # "chown: invalid user: 'bitspire:bitspire'". The installed system skips this
  # block because its .env already exists, which is why only live boots tripped.
  system.activationScripts.bitspire-env = {
    deps = [ "users" ];
    text = ''
      mkdir -p /var/lib/bitspire
      if [ ! -f /var/lib/bitspire/.env ]; then
        cp ${envTemplate} /var/lib/bitspire/.env
        chmod 600 /var/lib/bitspire/.env
        chown bitspire:bitspire /var/lib/bitspire/.env
      fi
    '';
  };

  # Reset display output after X starts (required for kexec boots where
  # the GPU wasn't reinitialized by BIOS firmware). Only the eDP-panel models
  # (Douro/Tejo) have an eDP-1 output; the Sintra drives HDMI-1, so the
  # `xrandr --output eDP-1` here just errors out — skip it there.
  systemd.services.display-reset = lib.mkIf (machineModel != "sintra") {
    description = "Reset eDP display output";
    after = [ "display-manager.service" ];
    requires = [ "display-manager.service" ];
    wantedBy = [ "graphical.target" ];
    before = [ "bitspire.service" ];
    serviceConfig = {
      Type = "oneshot";
      User = "bitspire";
      Environment = "DISPLAY=:0";
      ExecStart = "${pkgs.bash}/bin/bash -c '${pkgs.xorg.xrandr}/bin/xrandr --output eDP-1 --off; sleep 1; ${pkgs.xorg.xrandr}/bin/xrandr --output eDP-1 --auto'";
    };
  };

  # Low-RAM models (Douro/Tejo, 2GB) need a swap cushion or they hard-freeze
  # under memory pressure. The live system is RAM-rooted, so a /var/swapfile
  # lives in tmpfs — pointless, and its init fails on a fresh boot. Use
  # compressed RAM swap (zram) instead; no on-disk file required.
  zramSwap.enable = true;

  # The wg0 VPN tunnel (declared in configuration.nix) needs a provisioned key
  # at /var/lib/wireguard/wg0.key, which a fresh live boot doesn't have — it
  # fails and drags network-setup down with it. A live test image doesn't need
  # the VPN, so drop the interface entirely.
  networking.wireguard.interfaces = lib.mkForce { };

  # Clean /tmp on boot to prevent stale Nix build artifacts from filling disk
  boot.tmp.cleanOnBoot = true;

  # SSH password auth disabled — machines are provisioned with SSH keys.
  # Base configuration.nix sets PasswordAuthentication = false.

  # Serial port udev rules — generic permissions for all models
  services.udev.extraRules = lib.mkAfter (''
    KERNEL=="ttyS[0-9]*", MODE="0666"
    KERNEL=="ttyUSB[0-9]*", MODE="0666"
    KERNEL=="ttyACM[0-9]*", MODE="0666"
  '' + lib.optionalString (machineModel == "batm3") ''

    # ── BATM3 MEI BNR Advance USB CDC ACM ──────────────────────────────
    # Stable symlink for the bill validator (vendor 0x0bed = MEI)
    SUBSYSTEM=="tty", ATTRS{idVendor}=="0bed", SYMLINK+="ttyValidator"
  '' + lib.optionalString (machineModel == "tejo") ''

    # ── Tejo serial port symlinks ──────────────────────────────────────
    # Both UP Board and UP4000 rules are included so one ISO works on either.
    # Rules match different kernel paths so they don't conflict.

    # Printer (ttyJ4): UP Board via USB hub path, UP4000 via ttyUSB0
    KERNELS=="1-7.2:1.0", SYMLINK+="ttyJ4"
    KERNEL=="ttyUSB0", SYMLINK+="ttyJ4"

    # Validator (ttyJ5): UP Board via USB hub path, UP4000 via ttyUSB1
    KERNELS=="1-7.3:1.0", SYMLINK+="ttyJ5"
    KERNEL=="ttyUSB1", SYMLINK+="ttyJ5"

    # Dispenser (ttyJ7): UP Board uses ttyS1, UP4000 uses ttyS5
    KERNEL=="ttyS1", SYMLINK+="ttyJ7"
    KERNEL=="ttyS5", SYMLINK+="ttyJ7"

    # Legacy ttyAMA0 alias
    SUBSYSTEM=="tty", KERNEL=="ttyS1", SYMLINK+="ttyAMA0", GROUP="dialout"

    # ── Camera devices ─────────────────────────────────────────────────
    # QR scanner camera (A4tech USB, vendor 0ac8:0345)
    SUBSYSTEM=="video4linux", ATTR{index}=="0", KERNELS=="1-5", ATTRS{idVendor}=="0ac8", ATTRS{idProduct}=="0345", SYMLINK+="video-scan"
    SUBSYSTEM=="video4linux", ATTR{index}=="0", KERNELS=="1-2", ATTRS{idVendor}=="0ac8", ATTRS{idProduct}=="0345", SYMLINK+="video-scan"

    # Front-facing camera
    SUBSYSTEM=="video4linux", ATTR{index}=="0", KERNELS=="1-6", ATTRS{idVendor}=="0ac8", ATTRS{idProduct}=="0345", SYMLINK+="video-front"
    SUBSYSTEM=="video4linux", ATTR{index}=="0", KERNELS=="1-3", ATTRS{idVendor}=="0ac8", ATTRS{idProduct}=="0345", SYMLINK+="video-front"

    # ── LED SPI / peripherals ──────────────────────────────────────────
    KERNEL=="spidev1.0", SYMLINK+="ledspi"
    KERNEL=="spidev2.0", SYMLINK+="ledspi"

    # SPI and I2C group permissions
    SUBSYSTEM=="spidev", GROUP="spi", MODE="0660"
    SUBSYSTEM=="i2c-dev", GROUP="i2c", MODE="0660"

    # UP Board FPGA LED permissions
    SUBSYSTEM=="leds", KERNEL=="upboard:*", ACTION=="add|change", RUN+="${pkgs.findutils}/bin/find /sys$devpath -type f -exec ${pkgs.coreutils}/bin/chmod g+u {} + -exec ${pkgs.coreutils}/bin/chown :leds {} +"

    # Disable USB autosuspend (prevents serial adapters from sleeping)
    ACTION=="add", SUBSYSTEM=="usb", TEST=="power/control", ATTR{power/control}="on"
  '');
}