go/src/infra/cros/recovery/internal/components/cros/cros_frid.go

// Copyright 2026 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package cros

import (
	"context"
	"fmt"
	"strings"
	"time"

	"go.chromium.org/luci/common/errors"

	"go.chromium.org/infra/cros/recovery/internal/components"
)

// ReadFRID reads the FRID from an android-based device.
func ReadFRID(ctx context.Context, timeout time.Duration, run components.Runner) (string, error) {
	productSku, err := run(ctx, timeout, "getprop", "ro.boot.vendor.product.sku")
	if err != nil {
		return "", errors.Annotate(err, "get vendor product sku from output")
	}
	frid := normalizeVendorProductSku(productSku)
	if err := validateFRID(frid); err != nil {
		return "", err
	}
	return frid, nil
}

// normalizeVendorProductSku normalizes the output of getprop ro.boot.vendor.product.sku for further use in futility.
//
// sample output: spiffy_######
func normalizeVendorProductSku(output string) string {
	lowercased := strings.ToLower(output)
	l := strings.LastIndex(output, "_")
	if l == -1 {
		return lowercased
	}
	return fmt.Sprintf("google_%s", output[:l])
}

// validateFRID validates a frid right before we modify the ChromeOs object on the exec info. It is our last line of defense
func validateFRID(frid string) error {
	if frid == "" {
		return errors.New("frid cannot be empty")
	}
	if frid != strings.ToLower(frid) {
		return fmt.Errorf("frid %q is not exclusively lowercase", frid)
	}
	if !strings.HasPrefix(frid, "google_") {
		return fmt.Errorf("frid %q is missing google_ prefix", frid)
	}
	return nil
}