fix relativize_fd with nullptr

    // If we run the constructor we also already setup the mountdir

    assert(!mountdir_.empty());

    // Handle nullptr path: this is a valid POSIX scenario when AT_EMPTY_PATH is

    // set (e.g. statx/openat on a bare fd). Resolve dirfd to determine scope:

    //  - GekkoFS fd  → return its stored path as internal

    //  - external/unknown fd → return fd_unknown so the hook forwards to kernel

    if(raw_path == nullptr) {

        if(dirfd != AT_FDCWD && ofm_->exist(dirfd)) {

            relative_path = ofm_->get(dirfd)->path();

            return RelativizeStatus::internal;

        }

        // dirfd is either AT_FDCWD (which requires a valid path) or an

        // external fd — let the kernel handle it.

        return RelativizeStatus::fd_unknown;

    }

    // Skips paths that are used on locking places (i.e. java

    // /proc/sys/vm/overcommit_memory) and produces deadlocks as we call malloc

    // inside.

    if(dirfd == AT_FDCWD) {

        for(auto& excl_path : gkfs::path::excluded_paths) {

            // compare raw_path with excl_path

            if(raw_path != nullptr && raw_path[0] == gkfs::path::separator) {

            if(raw_path[0] == gkfs::path::separator) {

                if(strncmp(raw_path + 1, excl_path.c_str(),

                           excl_path.length()) == 0) {

                    return RelativizeStatus::external;

    std::string path;

    if(raw_path != nullptr && raw_path[0] != gkfs::path::separator) {

    if(raw_path[0] != gkfs::path::separator) {

        // path is relative

        if(dirfd == AT_FDCWD) {

            // path is relative to cwd