Function GetAPIKeyFromHelper

util/api_key_helper_unix.go:24–99

GetAPIKeyFromHelper executes a shell command to dynamically generate an API key. The command is executed in /bin/sh with a timeout controlled by the provided context. It returns the trimmed output from stdout, or an error if the command fails. On timeout, it kills the entire process group (shell an

(ctx context.Context, helperCmd string)

//
// Security note: The returned API key is sensitive and should not be logged.
func GetAPIKeyFromHelper(ctx context.Context, helperCmd string) (string, error) {
	if helperCmd == "" {
		return "", errors.New("api_key_helper command is empty")
	}

	// Create context with timeout if not already set
	if _, hasDeadline := ctx.Deadline(); !hasDeadline {
		var cancel context.CancelFunc
		ctx, cancel = context.WithTimeout(ctx, HelperTimeout)
		defer cancel()
	}

	// Execute command in /bin/sh
	cmd := exec.CommandContext(ctx, "/bin/sh", "-c", helperCmd)

	// Create a new process group so we can kill all descendants on timeout
	cmd.SysProcAttr = &syscall.SysProcAttr{
		Setpgid: true,
	}

	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	// Start the command
	if err := cmd.Start(); err != nil {
		return "", fmt.Errorf("api_key_helper start failed: %w", err)
	}

	// Wait for command completion in a goroutine
	done := make(chan error, 1)
	go func() {
		// Always Wait to avoid zombie processes
		done <- cmd.Wait()
	}()

	select {
	case err := <-done:
		// Command completed normally
		if err != nil {
			// Don't include stderr in error message as it might contain sensitive info
			return "", fmt.Errorf("api_key_helper command failed: %w", err)
		}
		apiKey := strings.TrimSpace(stdout.String())
		if apiKey == "" {
			return "", errors.New("api_key_helper command returned empty output")
		}
		return apiKey, nil

	case <-ctx.Done():
		// Timeout or cancellation: terminate the process group gracefully, then forcefully
		if cmd.Process == nil {
			// Process handle not initialized; wait for cleanup and report timeout
			<-done
			return "", fmt.Errorf("api_key_helper command timeout after %v", HelperTimeout)
		}
		pgid := cmd.Process.Pid