dirSetFileOwner

fn dirSetFileOwner(
    userdata: ?*anyopaque,
    dir: Dir,
    sub_path: []const u8,
    owner: ?File.Uid,
    group: ?File.Gid,
    options: Dir.SetFileOwnerOptions,
) Dir.SetFileOwnerError!void {
    const ev: *Evented = @ptrCast(@alignCast(userdata));
    var path_buffer: [c.PATH_MAX]u8 = undefined;
    const sub_path_posix = try pathToPosix(sub_path, &path_buffer);
    _ = ev;
    while (true) switch (c.errno(c.fchownat(
        dir.handle,
        sub_path_posix,
        owner orelse std.math.maxInt(c.uid_t),
        group orelse std.math.maxInt(c.gid_t),
        if (options.follow_symlinks) 0 else c.AT.SYMLINK_NOFOLLOW,
    ))) {
        .SUCCESS => return,
        .INTR => continue,
        .BADF => |err| return errnoBug(err), // likely fd refers to directory opened without `Dir.OpenOptions.iterate`
        .FAULT => |err| return errnoBug(err),
        .INVAL => |err| return errnoBug(err),
        .ACCES => return error.AccessDenied,
        .IO => return error.InputOutput,
        .LOOP => return error.SymLinkLoop,
        .NOENT => return error.FileNotFound,
        .NOMEM => return error.SystemResources,
        .NOTDIR => return error.FileNotFound,
        .PERM => return error.PermissionDenied,
        .ROFS => return error.ReadOnlyFileSystem,
        else => |err| return unexpectedErrno(err),
    };
}