Configure nix-on-droid

suites/nix-on-droid/default.nix

@@ -0,0 +1,59 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+with lib; let
+  sshdTmpDirectory = "${config.user.home}/sshd.tmp";
+  sshdDirectory = "${config.user.home}/.sshd";
+  authorizedKeys = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIETPyuxUVEmYyEW6PVC6BXqkhULHd/RvMm8fMbYhjTMV fern@muskduck";
+  port = 8022;
+
+  sshd-start = pkgs.writeScriptBin "sshd-start" ''
+    #!${pkgs.runtimeShell}
+
+    echo "Starting sshd in non-daemonized way on port ${toString port}"
+    ${pkgs.openssh}/bin/sshd -f "${sshdDirectory}/sshd_config" -D
+  '';
+in {
+  # NixOS version.
+  system.stateVersion = "24.05";
+
+  # Enable flakes.
+  nix.extraOptions = ''
+    experimental-features = nix-command flakes
+  '';
+
+  # SSHD script.
+  build.activation.sshd = ''
+    $DRY_RUN_CMD mkdir $VERBOSE_ARG --parents "${config.user.home}/.ssh"
+    $DRY_RUN_CMD cat ${authorizedKeys} > "${config.user.home}/.ssh/authorized_keys"
+
+    if [[ ! -d "${sshdDirectory}" ]]; then
+      $DRY_RUN_CMD rm $VERBOSE_ARG --recursive --force "${sshdTmpDirectory}"
+      $DRY_RUN_CMD mkdir $VERBOSE_ARG --parents "${sshdTmpDirectory}"
+
+      $VERBOSE_ECHO "Generating host keys..."
+      $DRY_RUN_CMD ${pkgs.openssh}/bin/ssh-keygen -t rsa -b 4096 -f "${sshdTmpDirectory}/ssh_host_rsa_key" -N ""
+
+      $VERBOSE_ECHO "Writing sshd_config..."
+      $DRY_RUN_CMD echo -e "HostKey ${sshdDirectory}/ssh_host_rsa_key\nPort ${toString port}\n" > "${sshdTmpDirectory}/sshd_config"
+
+      $DRY_RUN_CMD mv $VERBOSE_ARG "${sshdTmpDirectory}" "${sshdDirectory}"
+    fi
+  '';
+
+  # Install some packages.
+  environment.packages = with pkgs; [
+    aria2
+    fish
+    lynx
+    neovim
+    rsync
+    sshd-start
+    tmux
+    trash-cli
+    yazi
+  ];
+}