Confine local file installation paths

internal/fileops/sync_directory_windows.go

@@ -5,6 +5,7 @@ package fileops
 import (
 	"errors"
 	"fmt"
+	"os"
 
 	"golang.org/x/sys/windows"
 )
@@ -39,3 +40,13 @@ func syncDirectory(path string) error {
 	}
 	return err
 }
+
+func syncDirectoryFile(directory *os.File, path string) error {
+	err := directory.Sync()
+	if errors.Is(err, windows.ERROR_INVALID_FUNCTION) ||
+		errors.Is(err, windows.ERROR_INVALID_HANDLE) ||
+		errors.Is(err, windows.ERROR_NOT_SUPPORTED) {
+		return fmt.Errorf("%w for %q: %w", ErrDirectorySyncUnsupported, path, err)
+	}
+	return err
+}