dirStatFile

fn dirStatFile(
    userdata: ?*anyopaque,
    dir: Dir,
    sub_path: []const u8,
    options: Dir.StatFileOptions,
) Dir.StatFileError!File.Stat {
    const ev: *Evented = @ptrCast(@alignCast(userdata));
    _ = ev;

    var path_buffer: [c.PATH_MAX]u8 = undefined;
    const sub_path_posix = try pathToPosix(sub_path, &path_buffer);

    const flags: u32 = if (options.follow_symlinks) 0 else c.AT.SYMLINK_NOFOLLOW;

    while (true) {
        var stat = std.mem.zeroes(c.Stat);
        switch (c.errno(c.fstatat(dir.handle, sub_path_posix, &stat, flags))) {
            .SUCCESS => return statFromPosix(&stat),
            .INTR => {},
            .INVAL => |err| return errnoBug(err),
            .BADF => |err| return errnoBug(err), // File descriptor used after closed.
            .NOMEM => return error.SystemResources,
            .ACCES => return error.AccessDenied,
            .PERM => return error.PermissionDenied,
            .FAULT => |err| return errnoBug(err),
            .NAMETOOLONG => return error.NameTooLong,
            .LOOP => return error.SymLinkLoop,
            .NOENT => return error.FileNotFound,
            .NOTDIR => return error.FileNotFound,
            .ILSEQ => return error.BadPathName,
            else => |err| return unexpectedErrno(err),
        }
    }
}