nixpkgs/modules/nixos/pi-agent-wrapper.nix

{
  cfg,
  pkgs,
  lib,
  runner,
  ...
}:
with lib;
  pkgs.writeShellScriptBin cfg.wrapper.commandName ''
    set -euo pipefail

    user_name="$(id -un)"
    user_home="$(eval echo "~$user_name")"
    if [ -z "$user_home" ] || [ "$user_home" = "~$user_name" ]; then
      user_home="$HOME"
    fi

    resolve_user_policy() {
      local user="$1"
      USER_ROOTS=()
      case "$user" in
        ${concatStringsSep "\n" (
      mapAttrsToList (
        user: userCfg: ''
          ${escapeShellArg user})
            USER_ROOTS=(${concatStringsSep " " (map escapeShellArg userCfg.projectRoots)})
            ;;
        ''
      )
      cfg.hostUsers
    )}
        *)
          return 1
          ;;
      esac
      return 0
    }

    if ! resolve_user_policy "$user_name"; then
      echo "User '$user_name' is not allowed to use ${cfg.wrapper.commandName}" >&2
      exit 1
    fi

    expand_home_path() {
      local input="$1"
      if [ "$input" = "~" ]; then
        printf '%s\n' "$user_home"
      elif ${pkgs.gnugrep}/bin/grep -q '^~/' <<<"$input"; then
        printf '%s\n' "$user_home/''${input:2}"
      elif ${pkgs.gnugrep}/bin/grep -q '^/' <<<"$input"; then
        printf '%s\n' "$input"
      else
        printf '%s\n' "$user_home/$input"
      fi
    }

    cwd_real="$(${pkgs.coreutils}/bin/realpath -m "$PWD")"

    is_allowed_cwd=0
    resolved_roots=()
    skipped_roots=()
    for configured_root in "''${USER_ROOTS[@]}"; do
      expanded_root="$(expand_home_path "$configured_root")"
      resolved_root="$(${pkgs.coreutils}/bin/realpath -m "$expanded_root")"
      if [ ! -d "$resolved_root" ]; then
        skipped_roots+=("$resolved_root")
        continue
      fi
      resolved_roots+=("$resolved_root")
      case "$cwd_real/" in
        "$resolved_root"/*)
          is_allowed_cwd=1
          ;;
      esac
    done

    if [ "''${#resolved_roots[@]}" -eq 0 ]; then
      echo "Denied: no valid existing project roots are configured for user '$user_name'." >&2
      if [ "''${#skipped_roots[@]}" -gt 0 ]; then
        echo "Configured but missing roots:" >&2
        for root in "''${skipped_roots[@]}"; do
          echo "  - $root" >&2
        done
      fi
      exit 1
    fi

    if [ "$is_allowed_cwd" -ne 1 ]; then
      echo "Denied: '$cwd_real' is outside allowed project roots for user '$user_name'." >&2
      echo "Allowed roots:" >&2
      for root in "''${resolved_roots[@]}"; do
        echo "  - $root" >&2
      done
      exit 1
    fi

    exec /run/wrappers/bin/sudo --non-interactive \
      ${runner}/bin/${cfg.wrapper.runnerName} \
      "$user_name" "$cwd_real" \
      "TERM=$TERM" "LANG=$LANG" "LC_ALL=''${LC_ALL:-}" "LC_CTYPE=''${LC_CTYPE:-}" "COLORTERM=''${COLORTERM:-}" "TERM_PROGRAM=''${TERM_PROGRAM:-}" \
      "$@"
  ''