* WASI Filesystem support, initial implementation

packages/wasi/src/wasitypes.pas

@@ -0,0 +1,682 @@
+unit wasitypes;
+
+{$mode ObjFPC}
+{$INTERFACES CORBA}
+
+interface
+
+uses JS;
+
+Type
+  TWasmMemoryLocation = Integer;
+  // The imports as expected by WASI
+  IWASI = interface ['{A03AC61B-3C68-4DA8-AC4F-53ED01814673}']
+    // Please keep these sorted !!
+    function args_get(argc, argvBufSize : NativeInt) : NativeInt;
+    function args_sizes_get(argc, argvBufSize : NativeInt) : NativeInt;
+    function clock_res_get(clockId, resolution: NativeInt): NativeInt;
+
+    function clock_time_get(clockId, precision : NativeInt; time: TWasmMemoryLocation): NativeInt;
+    function environ_get(environ, environBuf : NativeInt) : NativeInt;
+    function environ_sizes_get(environCount, environBufSize : NativeInt) : NativeInt;
+    function fd_advise (fd, offset, len, advice : NativeInt) : NativeInt;
+    function fd_allocate (fd, offset, len : NativeInt) : NativeInt;
+    function fd_close(fd : NativeInt) : NativeInt;
+    function fd_datasync (fd : NativeInt) : NativeInt;
+    function fd_fdstat_get(fd : NativeInt; bufPtr: TWasmMemoryLocation) : NativeInt;
+    function fd_fdstat_set_flags (fd, flags: NativeInt) : NativeInt;
+    function fd_fdstat_set_rights (fd, fsRightsBase, fsRightsInheriting: NativeInt) : NativeInt;
+    function fd_filestat_get (fd : NativeInt; bufPtr: TWasmMemoryLocation) : NativeInt;
+    function fd_filestat_set_size (fd, stSize: NativeInt) : NativeInt;
+    function fd_filestat_set_times (fd, stAtim, stMtim, fstflags: NativeInt) : NativeInt;
+    function fd_pread(fd: NativeInt; iovs : TWasmMemoryLocation; iovsLen, offset: NativeInt; nread : TWasmMemoryLocation) : NativeInt;
+    function fd_prestat_dir_name(fd : NativeInt; pathPtr : TWasmMemoryLocation; pathLen : NativeInt) : NativeInt;
+    function fd_prestat_get(fd: NativeInt; bufPtr: TWasmMemoryLocation) : NativeInt;
+    function fd_pwrite(fd, iovs, iovsLen, offset, nwritten : NativeInt) : NativeInt;
+    function fd_read(fd: NativeInt; iovs : TWasmMemoryLocation; iovsLen: NativeInt; nread : TWasmMemoryLocation) : NativeInt;
+    function fd_readdir(fd, bufPtr, bufLen, cookie, bufusedPtr : NativeInt) : NativeInt;
+    function fd_renumber(afrom,ato : NativeInt) : NativeInt;
+    function fd_seek(fd, offset, whence : NativeInt; newOffsetPtr : TWasmMemoryLocation) : NativeInt;
+    function fd_sync(fd : NativeInt) : NativeInt;
+    function fd_tell(fd: NativeInt; offsetPtr: TWasmMemoryLocation): NativeInt;
+    function fd_write(fd,iovs,iovsLen,nwritten : NativeInt) : NativeInt;
+    function path_create_directory (fd, pathPtr, pathLen : NativeInt) : NativeInt;
+    function path_filestat_get (fd, flags : NativeInt; pathPtr : TWasmMemoryLocation;  pathLen : Nativeint; bufPtr : TWasmMemoryLocation) : NativeInt;
+    function path_filestat_set_times(fd, fstflags, pathPtr, pathLen, stAtim, stMtim : NativeInt) : NativeInt;
+    function path_link (oldFd, oldFlags : NativeInt; oldPath: TWasmMemoryLocation; oldPathLen, newFd : NativeInt; NewPath: TWasmMemoryLocation; newPathLen: NativeInt) : NativeInt;
+    function path_open (dirfd, dirflags : NativeInt; pathPtr : TWasmMemoryLocation; pathLen, oflags, fsRightsBase, fsRightsInheriting, fsFlags : NativeInt; fd : TWasmMemoryLocation) : NativeInt;
+    function path_readlink (fd: NativeInt; pathPtr: TWasmMemoryLocation; pathLen: NativeInt; buf: TWasmMemoryLocation; bufLen : NativeInt; bufused : TWasmMemoryLocation) : NativeInt;
+    function path_remove_directory (fd : NativeInt; pathPtr: TWasmMemoryLocation; pathLen : NativeInt) : NativeInt;
+    function path_rename (oldFd, oldPath, oldPathLen, newFd, newPath, newPathLen : NativeInt) : NativeInt;
+    function path_symlink (oldPath, oldPathLen, fd, newPath, newPathLen : NativeInt) : NativeInt;
+    function path_unlink_file (fd, pathPtr, pathLen : NativeInt) : NativeInt;
+    function poll_oneoff(sin, sout, nsubscriptions, nevents : NativeInt) : NativeInt;
+    function proc_exit(rval : NativeInt) : NativeInt;
+    function proc_raise (sig : NativeInt) : NativeInt;
+    function random_get (bufPtr, bufLen: NativeInt) : NativeInt;
+    function sched_yield() : NativeInt;
+    function sock_recv() : NativeInt;
+    function sock_send() : NativeInt;
+    function sock_shutdown() : NativeInt;
+  end;
+
+
+Const
+  WASI_ESUCCESS = 0;
+  WASI_E2BIG = 1;
+  WASI_EACCES = 2;
+  WASI_EADDRINUSE = 3;
+  WASI_EADDRNOTAVAIL = 4;
+  WASI_EAFNOSUPPORT = 5;
+  WASI_EAGAIN = 6;
+  WASI_EALREADY = 7;
+  WASI_EBADF = 8;
+  WASI_EBADMSG = 9;
+  WASI_EBUSY = 10;
+  WASI_ECANCELED = 11;
+  WASI_ECHILD = 12;
+  WASI_ECONNABORTED = 13;
+  WASI_ECONNREFUSED = 14;
+  WASI_ECONNRESET = 15;
+  WASI_EDEADLK = 16;
+  WASI_EDESTADDRREQ = 17;
+  WASI_EDOM = 18;
+  WASI_EDQUOT = 19;
+  WASI_EEXIST = 20;
+  WASI_EFAULT = 21;
+  WASI_EFBIG = 22;
+  WASI_EHOSTUNREACH = 23;
+  WASI_EIDRM = 24;
+  WASI_EILSEQ = 25;
+  WASI_EINPROGRESS = 26;
+  WASI_EINTR = 27;
+  WASI_EINVAL = 28;
+  WASI_EIO = 29;
+  WASI_EISCONN = 30;
+  WASI_EISDIR = 31;
+  WASI_ELOOP = 32;
+  WASI_EMFILE = 33;
+  WASI_EMLINK = 34;
+  WASI_EMSGSIZE = 35;
+  WASI_EMULTIHOP = 36;
+  WASI_ENAMETOOLONG = 37;
+  WASI_ENETDOWN = 38;
+  WASI_ENETRESET = 39;
+  WASI_ENETUNREACH = 40;
+  WASI_ENFILE = 41;
+  WASI_ENOBUFS = 42;
+  WASI_ENODEV = 43;
+  WASI_ENOENT = 44;
+  WASI_ENOEXEC = 45;
+  WASI_ENOLCK = 46;
+  WASI_ENOLINK = 47;
+  WASI_ENOMEM = 48;
+  WASI_ENOMSG = 49;
+  WASI_ENOPROTOOPT = 50;
+  WASI_ENOSPC = 51;
+  WASI_ENOSYS = 52;
+  WASI_ENOTCONN = 53;
+  WASI_ENOTDIR = 54;
+  WASI_ENOTEMPTY = 55;
+  WASI_ENOTRECOVERABLE = 56;
+  WASI_ENOTSOCK = 57;
+  WASI_ENOTSUP = 58;
+  WASI_ENOTTY = 59;
+  WASI_ENXIO = 60;
+  WASI_EOVERFLOW = 61;
+  WASI_EOWNERDEAD = 62;
+  WASI_EPERM = 63;
+  WASI_EPIPE = 64;
+  WASI_EPROTO = 65;
+  WASI_EPROTONOSUPPORT = 66;
+  WASI_EPROTOTYPE = 67;
+  WASI_ERANGE = 68;
+  WASI_EROFS = 69;
+  WASI_ESPIPE = 70;
+  WASI_ESRCH = 71;
+  WASI_ESTALE = 72;
+  WASI_ETIMEDOUT = 73;
+  WASI_ETXTBSY = 74;
+  WASI_EXDEV = 75;
+  WASI_ENOTCAPABLE = 76;
+
+  WASI_SIGABRT = 0;
+  WASI_SIGALRM = 1;
+  WASI_SIGBUS = 2;
+  WASI_SIGCHLD = 3;
+  WASI_SIGCONT = 4;
+  WASI_SIGFPE = 5;
+  WASI_SIGHUP = 6;
+  WASI_SIGILL = 7;
+  WASI_SIGINT = 8;
+  WASI_SIGKILL = 9;
+  WASI_SIGPIPE = 10;
+  WASI_SIGQUIT = 11;
+  WASI_SIGSEGV = 12;
+  WASI_SIGSTOP = 13;
+  WASI_SIGTERM = 14;
+  WASI_SIGTRAP = 15;
+  WASI_SIGTSTP = 16;
+  WASI_SIGTTIN = 17;
+  WASI_SIGTTOU = 18;
+  WASI_SIGURG = 19;
+  WASI_SIGUSR1 = 20;
+  WASI_SIGUSR2 = 21;
+  WASI_SIGVTALRM = 22;
+  WASI_SIGXCPU = 23;
+  WASI_SIGXFSZ = 24;
+
+  WASI_FILETYPE_UNKNOWN = 0;
+  WASI_FILETYPE_BLOCK_DEVICE = 1;
+  WASI_FILETYPE_CHARACTER_DEVICE = 2;
+  WASI_FILETYPE_DIRECTORY = 3;
+  WASI_FILETYPE_REGULAR_FILE = 4;
+  WASI_FILETYPE_SOCKET_DGRAM = 5;
+  WASI_FILETYPE_SOCKET_STREAM = 6;
+  WASI_FILETYPE_SYMBOLIC_LINK = 7;
+
+  WASI_FDFLAG_APPEND = $0001;
+  WASI_FDFLAG_DSYNC = $0002;
+  WASI_FDFLAG_NONBLOCK = $0004;
+  WASI_FDFLAG_RSYNC = $0008;
+  WASI_FDFLAG_SYNC = $0010;
+
+  WASI_RIGHT_FD_DATASYNC             = $0000000000000001;
+  WASI_RIGHT_FD_READ                 = $0000000000000002;
+  WASI_RIGHT_FD_SEEK                 = $0000000000000004;
+  WASI_RIGHT_FD_FDSTAT_SET_FLAGS     = $0000000000000008;
+  WASI_RIGHT_FD_SYNC                 = $0000000000000010;
+  WASI_RIGHT_FD_TELL                 = $0000000000000020;
+  WASI_RIGHT_FD_WRITE                = $0000000000000040;
+  WASI_RIGHT_FD_ADVISE               = $0000000000000080;
+  WASI_RIGHT_FD_ALLOCATE             = $0000000000000100;
+  WASI_RIGHT_PATH_CREATE_DIRECTORY   = $0000000000000200;
+  WASI_RIGHT_PATH_CREATE_FILE        = $0000000000000400;
+  WASI_RIGHT_PATH_LINK_SOURCE        = $0000000000000800;
+  WASI_RIGHT_PATH_LINK_TARGET        = $0000000000001000;
+  WASI_RIGHT_PATH_OPEN               = $0000000000002000;
+  WASI_RIGHT_FD_READDIR              = $0000000000004000;
+  WASI_RIGHT_PATH_READLINK           = $0000000000008000;
+  WASI_RIGHT_PATH_RENAME_SOURCE      = $0000000000010000;
+  WASI_RIGHT_PATH_RENAME_TARGET      = $0000000000020000;
+  WASI_RIGHT_PATH_FILESTAT_GET       = $0000000000040000;
+  WASI_RIGHT_PATH_FILESTAT_SET_SIZE  = $0000000000080000;
+  WASI_RIGHT_PATH_FILESTAT_SET_TIMES = $0000000000100000;
+  WASI_RIGHT_FD_FILESTAT_GET         = $0000000000200000;
+  WASI_RIGHT_FD_FILESTAT_SET_SIZE    = $0000000000400000;
+  WASI_RIGHT_FD_FILESTAT_SET_TIMES   = $0000000000800000;
+  WASI_RIGHT_PATH_SYMLINK            = $0000000001000000;
+  WASI_RIGHT_PATH_REMOVE_DIRECTORY   = $0000000002000000;
+  WASI_RIGHT_PATH_UNLINK_FILE        = $0000000004000000;
+  WASI_RIGHT_POLL_FD_READWRITE       = $0000000008000000;
+  WASI_RIGHT_SOCK_SHUTDOWN           = $0000000010000000;
+
+  RIGHTS_ALL = WASI_RIGHT_FD_DATASYNC or WASI_RIGHT_FD_READ
+  or WASI_RIGHT_FD_SEEK or WASI_RIGHT_FD_FDSTAT_SET_FLAGS or WASI_RIGHT_FD_SYNC
+  or WASI_RIGHT_FD_TELL or WASI_RIGHT_FD_WRITE or WASI_RIGHT_FD_ADVISE
+  or WASI_RIGHT_FD_ALLOCATE or WASI_RIGHT_PATH_CREATE_DIRECTORY
+  or WASI_RIGHT_PATH_CREATE_FILE or WASI_RIGHT_PATH_LINK_SOURCE
+  or WASI_RIGHT_PATH_LINK_TARGET or WASI_RIGHT_PATH_OPEN or WASI_RIGHT_FD_READDIR
+  or WASI_RIGHT_PATH_READLINK or WASI_RIGHT_PATH_RENAME_SOURCE
+  or WASI_RIGHT_PATH_RENAME_TARGET or WASI_RIGHT_PATH_FILESTAT_GET
+  or WASI_RIGHT_PATH_FILESTAT_SET_SIZE or WASI_RIGHT_PATH_FILESTAT_SET_TIMES
+  or WASI_RIGHT_FD_FILESTAT_GET or WASI_RIGHT_FD_FILESTAT_SET_TIMES
+  or WASI_RIGHT_FD_FILESTAT_SET_SIZE or WASI_RIGHT_PATH_SYMLINK
+  or WASI_RIGHT_PATH_UNLINK_FILE or WASI_RIGHT_PATH_REMOVE_DIRECTORY
+  or WASI_RIGHT_POLL_FD_READWRITE or WASI_RIGHT_SOCK_SHUTDOWN;
+
+  RIGHTS_BLOCK_DEVICE_BASE = RIGHTS_ALL;
+  RIGHTS_BLOCK_DEVICE_INHERITING = RIGHTS_ALL;
+
+  RIGHTS_CHARACTER_DEVICE_BASE = RIGHTS_ALL;
+  RIGHTS_CHARACTER_DEVICE_INHERITING = RIGHTS_ALL;
+
+  RIGHTS_REGULAR_FILE_BASE = WASI_RIGHT_FD_DATASYNC or WASI_RIGHT_FD_READ
+                           or WASI_RIGHT_FD_SEEK or WASI_RIGHT_FD_FDSTAT_SET_FLAGS or WASI_RIGHT_FD_SYNC
+                           or WASI_RIGHT_FD_TELL or WASI_RIGHT_FD_WRITE or WASI_RIGHT_FD_ADVISE
+                           or WASI_RIGHT_FD_ALLOCATE or WASI_RIGHT_FD_FILESTAT_GET
+                           or WASI_RIGHT_FD_FILESTAT_SET_SIZE or WASI_RIGHT_FD_FILESTAT_SET_TIMES
+                           or WASI_RIGHT_POLL_FD_READWRITE;
+  RIGHTS_REGULAR_FILE_INHERITING = 00;
+
+  RIGHTS_DIRECTORY_BASE = WASI_RIGHT_FD_FDSTAT_SET_FLAGS
+                        or WASI_RIGHT_FD_SYNC or WASI_RIGHT_FD_ADVISE or WASI_RIGHT_PATH_CREATE_DIRECTORY
+                        or WASI_RIGHT_PATH_CREATE_FILE or WASI_RIGHT_PATH_LINK_SOURCE
+                        or WASI_RIGHT_PATH_LINK_TARGET or WASI_RIGHT_PATH_OPEN or WASI_RIGHT_FD_READDIR
+                        or WASI_RIGHT_PATH_READLINK or WASI_RIGHT_PATH_RENAME_SOURCE
+                        or WASI_RIGHT_PATH_RENAME_TARGET or WASI_RIGHT_PATH_FILESTAT_GET
+                        or WASI_RIGHT_PATH_FILESTAT_SET_SIZE or WASI_RIGHT_PATH_FILESTAT_SET_TIMES
+                        or WASI_RIGHT_FD_FILESTAT_GET or WASI_RIGHT_FD_FILESTAT_SET_TIMES
+                        or WASI_RIGHT_PATH_SYMLINK or WASI_RIGHT_PATH_UNLINK_FILE
+                        or WASI_RIGHT_PATH_REMOVE_DIRECTORY or WASI_RIGHT_POLL_FD_READWRITE;
+  RIGHTS_DIRECTORY_INHERITING = RIGHTS_DIRECTORY_BASE
+                        or RIGHTS_REGULAR_FILE_BASE;
+
+  RIGHTS_SOCKET_BASE = WASI_RIGHT_FD_READ or WASI_RIGHT_FD_FDSTAT_SET_FLAGS
+                     or WASI_RIGHT_FD_WRITE or WASI_RIGHT_FD_FILESTAT_GET
+                     or WASI_RIGHT_POLL_FD_READWRITE or WASI_RIGHT_SOCK_SHUTDOWN;
+
+  RIGHTS_SOCKET_INHERITING = RIGHTS_ALL;
+
+  RIGHTS_TTY_BASE = WASI_RIGHT_FD_READ or WASI_RIGHT_FD_FDSTAT_SET_FLAGS
+                  or WASI_RIGHT_FD_WRITE or WASI_RIGHT_FD_FILESTAT_GET
+                  or WASI_RIGHT_POLL_FD_READWRITE;
+
+  RIGHTS_TTY_INHERITING = 0;
+
+  WASI_CLOCK_MONOTONIC = 0;
+  WASI_CLOCK_PROCESS_CPUTIME_ID = 1;
+  WASI_CLOCK_REALTIME = 2;
+  WASI_CLOCK_THREAD_CPUTIME_ID = 3;
+
+  WASI_EVENTTYPE_CLOCK = 0;
+  WASI_EVENTTYPE_FD_READ = 1;
+  WASI_EVENTTYPE_FD_WRITE = 2;
+
+  WASI_FILESTAT_SET_ATIM = 1 << 0;
+  WASI_FILESTAT_SET_ATIM_NOW = 1 << 1;
+  WASI_FILESTAT_SET_MTIM = 1 << 2;
+  WASI_FILESTAT_SET_MTIM_NOW = 1 << 3;
+
+  WASI_O_CREAT = 1 << 0;
+  WASI_O_DIRECTORY = 1 << 1;
+  WASI_O_EXCL = 1 << 2;
+  WASI_O_TRUNC = 1 << 3;
+
+  WASI_PREOPENTYPE_DIR = 0;
+
+  WASI_DIRCOOKIE_START = 0;
+
+  WASI_STDIN_FILENO = 0;
+  WASI_STDOUT_FILENO = 1;
+  WASI_STDERR_FILENO = 2;
+
+  WASI_WHENCE_CUR = 0;
+  WASI_WHENCE_END = 1;
+  WASI_WHENCE_SET = 2;
+
+  __WASI_CLOCKID_REALTIME           = 0;
+  __WASI_CLOCKID_MONOTONIC          = 1;
+  __WASI_CLOCKID_PROCESS_CPUTIME_ID = 2;
+  __WASI_CLOCKID_THREAD_CPUTIME_ID  = 3;
+
+  __WASI_ERRNO_SUCCESS        = 0;
+  __WASI_ERRNO_2BIG           = 1;
+  __WASI_ERRNO_ACCES          = 2;
+  __WASI_ERRNO_ADDRINUSE      = 3;
+  __WASI_ERRNO_ADDRNOTAVAIL   = 4;
+  __WASI_ERRNO_AFNOSUPPORT    = 5;
+  __WASI_ERRNO_AGAIN          = 6;
+  __WASI_ERRNO_ALREADY        = 7;
+  __WASI_ERRNO_BADF           = 8;
+  __WASI_ERRNO_BADMSG         = 9;
+  __WASI_ERRNO_BUSY           = 10;
+  __WASI_ERRNO_CANCELED       = 11;
+  __WASI_ERRNO_CHILD          = 12;
+  __WASI_ERRNO_CONNABORTED    = 13;
+  __WASI_ERRNO_CONNREFUSED    = 14;
+  __WASI_ERRNO_CONNRESET      = 15;
+  __WASI_ERRNO_DEADLK         = 16;
+  __WASI_ERRNO_DESTADDRREQ    = 17;
+  __WASI_ERRNO_DOM            = 18;
+  __WASI_ERRNO_DQUOT          = 19;
+  __WASI_ERRNO_EXIST          = 20;
+  __WASI_ERRNO_FAULT          = 21;
+  __WASI_ERRNO_FBIG           = 22;
+  __WASI_ERRNO_HOSTUNREACH    = 23;
+  __WASI_ERRNO_IDRM           = 24;
+  __WASI_ERRNO_ILSEQ          = 25;
+  __WASI_ERRNO_INPROGRESS     = 26;
+  __WASI_ERRNO_INTR           = 27;
+  __WASI_ERRNO_INVAL          = 28;
+  __WASI_ERRNO_IO             = 29;
+  __WASI_ERRNO_ISCONN         = 30;
+  __WASI_ERRNO_ISDIR          = 31;
+  __WASI_ERRNO_LOOP           = 32;
+  __WASI_ERRNO_MFILE          = 33;
+  __WASI_ERRNO_MLINK          = 34;
+  __WASI_ERRNO_MSGSIZE        = 35;
+  __WASI_ERRNO_MULTIHOP       = 36;
+  __WASI_ERRNO_NAMETOOLONG    = 37;
+  __WASI_ERRNO_NETDOWN        = 38;
+  __WASI_ERRNO_NETRESET       = 39;
+  __WASI_ERRNO_NETUNREACH     = 40;
+  __WASI_ERRNO_NFILE          = 41;
+  __WASI_ERRNO_NOBUFS         = 42;
+  __WASI_ERRNO_NODEV          = 43;
+  __WASI_ERRNO_NOENT          = 44;
+  __WASI_ERRNO_NOEXEC         = 45;
+  __WASI_ERRNO_NOLCK          = 46;
+  __WASI_ERRNO_NOLINK         = 47;
+  __WASI_ERRNO_NOMEM          = 48;
+  __WASI_ERRNO_NOMSG          = 49;
+  __WASI_ERRNO_NOPROTOOPT     = 50;
+  __WASI_ERRNO_NOSPC          = 51;
+  __WASI_ERRNO_NOSYS          = 52;
+  __WASI_ERRNO_NOTCONN        = 53;
+  __WASI_ERRNO_NOTDIR         = 54;
+  __WASI_ERRNO_NOTEMPTY       = 55;
+  __WASI_ERRNO_NOTRECOVERABLE = 56;
+  __WASI_ERRNO_NOTSOCK        = 57;
+  __WASI_ERRNO_NOTSUP         = 58;
+  __WASI_ERRNO_NOTTY          = 59;
+  __WASI_ERRNO_NXIO           = 60;
+  __WASI_ERRNO_OVERFLOW       = 61;
+  __WASI_ERRNO_OWNERDEAD      = 62;
+  __WASI_ERRNO_PERM           = 63;
+  __WASI_ERRNO_PIPE           = 64;
+  __WASI_ERRNO_PROTO          = 65;
+  __WASI_ERRNO_PROTONOSUPPORT = 66;
+  __WASI_ERRNO_PROTOTYPE      = 67;
+  __WASI_ERRNO_RANGE          = 68;
+  __WASI_ERRNO_ROFS           = 69;
+  __WASI_ERRNO_SPIPE          = 70;
+  __WASI_ERRNO_SRCH           = 71;
+  __WASI_ERRNO_STALE          = 72;
+  __WASI_ERRNO_TIMEDOUT       = 73;
+  __WASI_ERRNO_TXTBSY         = 74;
+  __WASI_ERRNO_XDEV           = 75;
+  __WASI_ERRNO_NOTCAPABLE     = 76;
+
+
+const
+  __WASI_RIGHTS_FD_DATASYNC             = 1;
+  __WASI_RIGHTS_FD_READ                 = 2;
+  __WASI_RIGHTS_FD_SEEK                 = 4;
+  __WASI_RIGHTS_FD_FDSTAT_SET_FLAGS     = 8;
+  __WASI_RIGHTS_FD_SYNC                 = 16;
+  __WASI_RIGHTS_FD_TELL                 = 32;
+  __WASI_RIGHTS_FD_WRITE                = 64;
+  __WASI_RIGHTS_FD_ADVISE               = 128;
+  __WASI_RIGHTS_FD_ALLOCATE             = 256;
+  __WASI_RIGHTS_PATH_CREATE_DIRECTORY   = 512;
+  __WASI_RIGHTS_PATH_CREATE_FILE        = 1024;
+  __WASI_RIGHTS_PATH_LINK_SOURCE        = 2048;
+  __WASI_RIGHTS_PATH_LINK_TARGET        = 4096;
+  __WASI_RIGHTS_PATH_OPEN               = 8192;
+  __WASI_RIGHTS_FD_READDIR              = 16384;
+  __WASI_RIGHTS_PATH_READLINK           = 32768;
+  __WASI_RIGHTS_PATH_RENAME_SOURCE      = 65536;
+  __WASI_RIGHTS_PATH_RENAME_TARGET      = 131072;
+  __WASI_RIGHTS_PATH_FILESTAT_GET       = 262144;
+  __WASI_RIGHTS_PATH_FILESTAT_SET_SIZE  = 524288;
+  __WASI_RIGHTS_PATH_FILESTAT_SET_TIMES = 1048576;
+  __WASI_RIGHTS_FD_FILESTAT_GET         = 2097152;
+  __WASI_RIGHTS_FD_FILESTAT_SET_SIZE    = 4194304;
+  __WASI_RIGHTS_FD_FILESTAT_SET_TIMES   = 8388608;
+  __WASI_RIGHTS_PATH_SYMLINK            = 16777216;
+  __WASI_RIGHTS_PATH_REMOVE_DIRECTORY   = 33554432;
+  __WASI_RIGHTS_PATH_UNLINK_FILE        = 67108864;
+  __WASI_RIGHTS_POLL_FD_READWRITE       = 134217728;
+  __WASI_RIGHTS_SOCK_SHUTDOWN           = 268435456;
+
+const
+  __WASI_SIGNAL_NONE   = 0;
+  __WASI_SIGNAL_HUP    = 1;
+  __WASI_SIGNAL_INT    = 2;
+  __WASI_SIGNAL_QUIT   = 3;
+  __WASI_SIGNAL_ILL    = 4;
+  __WASI_SIGNAL_TRAP   = 5;
+  __WASI_SIGNAL_ABRT   = 6;
+  __WASI_SIGNAL_BUS    = 7;
+  __WASI_SIGNAL_FPE    = 8;
+  __WASI_SIGNAL_KILL   = 9;
+  __WASI_SIGNAL_USR1   = 10;
+  __WASI_SIGNAL_SEGV   = 11;
+  __WASI_SIGNAL_USR2   = 12;
+  __WASI_SIGNAL_PIPE   = 13;
+  __WASI_SIGNAL_ALRM   = 14;
+  __WASI_SIGNAL_TERM   = 15;
+  __WASI_SIGNAL_CHLD   = 16;
+  __WASI_SIGNAL_CONT   = 17;
+  __WASI_SIGNAL_STOP   = 18;
+  __WASI_SIGNAL_TSTP   = 19;
+  __WASI_SIGNAL_TTIN   = 20;
+  __WASI_SIGNAL_TTOU   = 21;
+  __WASI_SIGNAL_URG    = 22;
+  __WASI_SIGNAL_XCPU   = 23;
+  __WASI_SIGNAL_XFSZ   = 24;
+  __WASI_SIGNAL_VTALRM = 25;
+  __WASI_SIGNAL_PROF   = 26;
+  __WASI_SIGNAL_WINCH  = 27;
+  __WASI_SIGNAL_POLL   = 28;
+  __WASI_SIGNAL_PWR    = 29;
+  __WASI_SIGNAL_SYS    = 30;
+
+  __WASI_ROFLAGS_RECV_DATA_TRUNCATED = 1;
+
+
+const
+  __WASI_WHENCE_SET = 0;
+  __WASI_WHENCE_CUR = 1;
+  __WASI_WHENCE_END = 2;
+
+  __WASI_FILETYPE_UNKNOWN          = 0;
+  __WASI_FILETYPE_BLOCK_DEVICE     = 1;
+  __WASI_FILETYPE_CHARACTER_DEVICE = 2;
+  __WASI_FILETYPE_DIRECTORY        = 3;
+  __WASI_FILETYPE_REGULAR_FILE     = 4;
+  __WASI_FILETYPE_SOCKET_DGRAM     = 5;
+  __WASI_FILETYPE_SOCKET_STREAM    = 6;
+  __WASI_FILETYPE_SYMBOLIC_LINK    = 7;
+
+
+
+  __WASI_OFLAGS_CREAT     = 1;
+  __WASI_OFLAGS_DIRECTORY = 2;
+  __WASI_OFLAGS_EXCL      = 4;
+  __WASI_OFLAGS_TRUNC     = 8;
+
+  __WASI_FSTFLAGS_ATIM     = 1;
+  __WASI_FSTFLAGS_ATIM_NOW = 2;
+  __WASI_FSTFLAGS_MTIM     = 4;
+  __WASI_FSTFLAGS_MTIM_NOW = 8;
+
+  __WASI_ADVICE_NORMAL     = 0;
+  __WASI_ADVICE_SEQUENTIAL = 1;
+  __WASI_ADVICE_RANDOM     = 2;
+  __WASI_ADVICE_WILLNEED   = 3;
+  __WASI_ADVICE_DONTNEED   = 4;
+  __WASI_ADVICE_NOREUSE    = 5;
+
+
+  __WASI_FDFLAGS_APPEND   = 1;
+  __WASI_FDFLAGS_DSYNC    = 2;
+  __WASI_FDFLAGS_NONBLOCK = 4;
+  __WASI_FDFLAGS_RSYNC    = 8;
+  __WASI_FDFLAGS_SYNC     = 16;
+
+
+
+  __WASI_SUBCLOCKFLAGS_SUBSCRIPTION_CLOCK_ABSTIME = 1;
+
+  __WASI_RIFLAGS_RECV_PEEK    = 1;
+  __WASI_RIFLAGS_RECV_WAITALL = 2;
+
+  __WASI_LOOKUPFLAGS_SYMLINK_FOLLOW = 1;
+
+  __WASI_EVENTRWFLAGS_FD_READWRITE_HANGUP = 1;
+
+type
+  PUInt8 = NativeInt;
+  size_t = longint;
+
+  __wasi_size_t = longint;
+  __wasi_filesize_t = UInt64;
+  __wasi_timestamp_t = UInt64;
+  __wasi_clockid_t = UInt32;
+  __wasi_errno_t = UInt16;
+  __wasi_fd_t = longint;
+  __wasi_filedelta_t = Int64;
+  __wasi_whence_t = UInt8;
+  __wasi_dircookie_t = UInt64;
+  __wasi_dirnamlen_t = UInt32;
+  __wasi_inode_t = UInt64;
+  __wasi_filetype_t = UInt8;
+  __wasi_rights_t = UInt64;
+  __wasi_exitcode_t = UInt32;
+  __wasi_signal_t = UInt8;
+  __wasi_riflags_t = UInt16;
+  __wasi_roflags_t = UInt16;
+  __wasi_siflags_t = UInt16;
+  __wasi_sdflags_t = UInt8;
+  __wasi_preopentype_t = UInt8;
+  __wasi_advice_t = UInt8;
+  __wasi_fdflags_t = UInt16;
+  __wasi_device_t = UInt64;
+  __wasi_fstflags_t = UInt16;
+  __wasi_lookupflags_t = UInt32;
+  __wasi_oflags_t = UInt16;
+  __wasi_linkcount_t = UInt64;
+  __wasi_userdata_t = UInt64;
+  __wasi_eventtype_t = UInt8;
+  __wasi_eventrwflags_t = UInt16;
+  __wasi_subclockflags_t = UInt16;
+
+
+
+  __wasi_iovec_t = record
+    buf: PUInt8;
+    buf_len: __wasi_size_t;
+  end;
+  TWASIIOVec = __wasi_iovec_t;
+
+  __wasi_ciovec_t = record
+    buf: PUInt8;
+    buf_len: __wasi_size_t;
+  end;
+  TWASICIOVec = __wasi_ciovec_t;
+
+  __wasi_dirent_t = record
+    d_next: __wasi_dircookie_t;
+    d_ino: __wasi_inode_t;
+    d_namlen: __wasi_dirnamlen_t;
+    d_type: __wasi_filetype_t;
+  end;
+  TWASIDirent = __wasi_dirent_t;
+
+  __wasi_fdstat_t = record
+    fs_filetype: __wasi_filetype_t;
+    fs_flags: __wasi_fdflags_t;
+    fs_rights_base: __wasi_rights_t;
+    fs_rights_inheriting: __wasi_rights_t;
+  end;
+  TWASIFDStat = __wasi_fdstat_t;
+
+  __wasi_filestat_t = record
+    dev: __wasi_device_t;
+    ino: __wasi_inode_t;
+    filetype: __wasi_filetype_t;
+    nlink: __wasi_linkcount_t;
+    size: __wasi_filesize_t;
+    atim: __wasi_timestamp_t;
+    mtim: __wasi_timestamp_t;
+    ctim: __wasi_timestamp_t;
+  end;
+  TWASIFilestat = __wasi_filestat_t;
+
+  __wasi_event_fd_readwrite_t = record
+    nbytes: __wasi_filesize_t;
+    flags: __wasi_eventrwflags_t;
+  end;
+  TWASIEventFDReadWrite = __wasi_event_fd_readwrite_t;
+
+  __wasi_event_t = record
+    userdata: __wasi_userdata_t;
+    error: __wasi_errno_t;
+    type_: __wasi_eventtype_t;
+    fd_readwrite: __wasi_event_fd_readwrite_t;
+  end;
+  TWASIEvent = __wasi_event_t;
+
+  __wasi_subscription_clock_t = record
+    id: __wasi_clockid_t;
+    timeout: __wasi_timestamp_t;
+    precision: __wasi_timestamp_t;
+    flags: __wasi_subclockflags_t;
+  end;
+  TWASISubscriptionClock = __wasi_subscription_clock_t;
+
+  __wasi_subscription_fd_readwrite_t = record
+    file_descriptor: __wasi_fd_t;
+  end;
+  TWASISubscriptionDSReadWrite = __wasi_subscription_fd_readwrite_t;
+
+  // The following 3 represent a part of the variant record.
+  __wasi_subscription_u_u_t_0 = record
+    clock: __wasi_subscription_clock_t;
+  end;
+  __wasi_subscription_u_u_t_1 = record
+    fd_read: __wasi_subscription_fd_readwrite_t
+  end;
+  __wasi_subscription_u_u_t_2 = record
+    fd_write: __wasi_subscription_fd_readwrite_t
+  end;
+
+  __wasi_subscription_u_u_t = Record
+    // Note, this is a variant record
+     Clock :  __wasi_subscription_clock_t; {case 0}
+     fd_read: __wasi_subscription_fd_readwrite_t; {case 1}
+     fd_write: __wasi_subscription_fd_readwrite_t; {case 2}
+  end;
+
+  __wasi_subscription_u_t = record
+    tag: __wasi_eventtype_t;
+    u: __wasi_subscription_u_u_t;
+  end;
+
+  __wasi_subscription_t = record
+    userdata: __wasi_userdata_t;
+    u: __wasi_subscription_u_t;
+  end;
+
+  __wasi_prestat_dir_t = record
+    pr_name_len: __wasi_size_t;
+  end;
+  TWASIPrestatDir = __wasi_prestat_dir_t;
+
+  __wasi_prestat_u_t = record
+     dir: __wasi_prestat_dir_t;
+  end;
+  TWasiPrestatU = __wasi_prestat_u_t;
+
+  __wasi_prestat_t = record
+    tag: __wasi_preopentype_t;
+    u: __wasi_prestat_u_t;
+  end;
+  TWasiPreStat = __wasi_prestat_t;
+
+
+  { EWasiFSError }
+
+  { IWASIFS }
+  TSeekWhence = (swBeginning, swCurrent, swEnd);
+  TSetTimesFlag = (stfatime,stfaTimeNow,stfmTime,stfmTimeNow);
+  TSetTimesFlags = set of TSetTimesFlag;
+
+  IWASIFS = Interface
+    Function MkDirAt(FD : Integer; const aPath : String) : NativeInt;
+    Function RmDirAt(FD : Integer; const aPath : String) : NativeInt;
+    function StatAt(FD : Integer; const aPath : String; var stat: TWasiFileStat) : NativeInt;
+    function StatFD(FD : Integer; var stat: TWasiFileStat) : NativeInt;
+    Function UTimesAt(FD : Integer; aPath : String; aTime,MTime : TJSDate; UpdateLink : boolean) : NativeInt;
+    Function UTimes(FD : Integer; aTime,MTime : TJSDate; Flags : TSetTimesFlags) : NativeInt;
+    Function LinkAt(OldFD : Integer; OldPath : String; NewFD : Integer; NewPath : String) : NativeInt;
+    Function SymLinkAt(FD : Integer; Path : String; Target : String) : NativeInt;
+    Function RenameAt(OldFD : Integer; OldPath : String; NewFD : Integer; NewPath : String) : NativeInt;
+    Function UnLinkAt(FD : Integer; const aPath : String) : NativeInt;
+    function OpenAt(FD : Integer; FDFlags : NativeInt; aPath : String; Flags, fsRightsBase, fsRightsInheriting, fsFlags: NativeInt; out Openfd: Integer): NativeInt;
+    function ReadLinkAt(FD : Integer; aPath : String; out aTarget : String): NativeInt;
+    function Close(FD : Integer): NativeInt;
+    function Write(FD : Integer; Data : TJSUint8Array; AtPos : Integer; Out Written : Integer) : NativeInt;
+    function Sync(FD : Integer) : NativeInt;
+    function DataSync(FD : Integer) : NativeInt;
+    function Seek(FD : integer; Offset : Integer; Whence : TSeekWhence; out NewPos : Integer) : NativeInt;
+    Function Read(FD : Integer; Data : TJSUint8Array; AtPos : Integer; Out BytesRead : Integer) : NativeInt;
+    Function GetPrestat(FD: Integer) : String;
+  end;
+
+implementation
+
+end.
+

packages/wasi/src/wasizenfs.pas

@@ -0,0 +1,444 @@
+unit wasizenfs;
+
+{$mode ObjFPC}
+
+interface
+
+uses
+  JS, libzenfs, Wasitypes;
+
+Type
+
+  { TWASIZenFS }
+
+  TWASIZenFS = class (TObject,IWasiFS)
+  private
+    FRoot : TZenFSDir;
+  protected
+    function PrependFD(FD: Integer; aPath: String): string;
+    class function ExceptToError(E : TJSObject) : Integer;
+    class function ZenFSDateToWasiTimeStamp(aDate: TJSDate): Nativeint;
+    class function ZenStatToWasiStat(ZSTat: TZenFSStats): TWasiFileStat;
+  Public
+    Function MkDirAt(FD : Integer; const aPath : String) : NativeInt;
+    Function RmDirAt(FD : Integer; const aPath : String) : NativeInt;
+    function StatAt(FD : Integer; const aPath : String; var stat: TWasiFileStat) : NativeInt;
+    function StatFD(FD : Integer; var stat: TWasiFileStat) : NativeInt;
+    Function UTimesAt(FD : Integer; aPath : String; aTime,MTime : TJSDate; UpdateLink : boolean) : NativeInt;
+    Function UTimes(FD : Integer; aTime,MTime : TJSDate; Flags : TSetTimesFlags) : NativeInt;
+    Function LinkAt(OldFD : Integer; OldPath : String; NewFD : Integer; NewPath : String) : NativeInt;
+    Function RenameAt(OldFD : Integer; OldPath : String; NewFD : Integer; NewPath : String) : NativeInt;
+    Function SymLinkAt(FD : Integer; Path : String; Target : String) : NativeInt;
+    Function UnLinkAt(FD : Integer; const aPath : String) : NativeInt;
+    function OpenAt(FD : Integer; FDFlags : NativeInt; aPath : String; Flags, fsRightsBase, fsRightsInheriting, fsFlags: NativeInt; out Openfd: Integer): NativeInt;
+    function ReadLinkAt(FD : Integer; aPath : String; out aTarget : String): NativeInt;
+    function Close(FD: Integer): NativeInt;
+    function Write(FD : Integer; Data : TJSUint8Array; AtPos : Integer; out Written :Integer) : NativeInt;
+    function Sync(FD : Integer) : NativeInt;
+    function DataSync(FD : Integer) : NativeInt;
+    function Seek(FD : integer; Offset : Integer; Whence : TSeekWhence; out NewPos : Integer) : NativeInt;
+    Function Read(FD : Integer; Data : TJSUint8Array; AtPos : Integer; Out BytesRead : Integer) : NativeInt;
+    Function GetPrestat(FD: Integer) : String;
+  end;
+
+implementation
+
+const
+  ResOK = __WASI_ERRNO_SUCCESS;
+
+{ TWASIZenFS }
+
+function TWASIZenFS.PrependFD(FD: Integer; aPath: String) : string;
+
+begin
+  if FD<>3 then
+    Writeln('Warning, unknown CWD ID',FD);
+  Result:='/'+aPath;
+end;
+
+class function TWASIZenFS.ExceptToError(E: TJSObject): Integer;
+begin
+  if Assigned(E) then;
+  // For the moment.
+  Result:=WASI_ENOSYS;
+end;
+
+function TWASIZenFS.MkDirAt(FD: Integer; const aPath: String): NativeInt;
+begin
+  try
+    ZenFS.mkdirSync(PrependFD(FD,aPath),&777);
+    Result:=ResOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.RmDirAt(FD: Integer; const aPath: String): NativeInt;
+begin
+  try
+    ZenFS.rmdirSync(PrependFD(FD,aPath));
+    Result:=ResOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+class function TWASIZenFS.ZenFSDateToWasiTimeStamp(aDate: TJSDate): Nativeint;
+begin
+  Result:=aDate.Time;
+end;
+
+class function TWASIZenFS.ZenStatToWasiStat(ZSTat: TZenFSStats): TWasiFileStat;
+
+begin
+  Result.dev:=0;
+  Result.ino:=0;
+  if ZStat.isDirectory then
+    Result.filetype:=__WASI_FILETYPE_DIRECTORY
+  else if ZSTat.isBlockDevice then
+    Result.filetype:=__WASI_FILETYPE_BLOCK_DEVICE
+  else if ZStat.isCharacterDevice then
+    Result.filetype:=__WASI_FILETYPE_CHARACTER_DEVICE
+  else if ZStat.isFile then
+    Result.filetype:=__WASI_FILETYPE_REGULAR_FILE
+  else if ZStat.isSocket() then
+    Result.filetype:=__WASI_FILETYPE_SOCKET_DGRAM
+  else if ZStat.isSymbolicLink() then
+    Result.filetype:=__WASI_FILETYPE_SYMBOLIC_LINK
+  else
+    Result.filetype:=__WASI_FILETYPE_UNKNOWN;
+  Result.nlink:=AsIntNumber(ZStat.nlink);
+  Result.size:=AsIntNumber(ZStat.Size);
+  Result.atim:=ZenFSDateToWasiTimeStamp(ZStat.aTime);
+  Result.mtim:=ZenFSDateToWasiTimeStamp(ZStat.mTime);
+  Result.ctim:=ZenFSDateToWasiTimeStamp(ZStat.cTime);
+end;
+
+function TWASIZenFS.StatAt(FD: Integer; const aPath: String;
+  var stat: TWasiFileStat): NativeInt;
+
+var
+  ZStat : TZenFSStats;
+
+begin
+  try
+    ZStat:=ZenFS.statSync(PrependFD(FD,aPath));
+    Stat:=ZenStatToWasiStat(ZStat);
+    Result:=ResOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.StatFD(FD: Integer; var stat: TWasiFileStat): NativeInt;
+var
+  ZStat : TZenFSStats;
+
+begin
+  try
+    ZStat:=ZenFS.fstatSync(FD);
+    Stat:=ZenStatToWasiStat(ZStat);
+    Result:=ResOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.UTimesAt(FD : Integer; aPath: String; aTime, MTime: TJSDate; UpdateLink: boolean): NativeInt;
+
+var
+  lPath : String;
+
+begin
+  lPath:=PrependFD(FD,aPath);
+  try
+    if UpdateLink then
+      ZenFS.lutimesSync(lPath,aTime,mTime)
+    else
+      ZenFS.utimesSync(lPath,aTime,mTime);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.UTimes(FD: Integer; aTime, MTime: TJSDate;
+  Flags: TSetTimesFlags): NativeInt;
+begin
+  try
+    ZenFS.futimes(fd,aTime,mTime);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.LinkAt(OldFD: Integer; OldPath: String; NewFD: Integer;
+  NewPath: String): NativeInt;
+
+var
+  lOld,lNew : String;
+
+begin
+  lOld:=PrependFD(OldFD,OldPath);
+  lNew:=PrependFD(NewFD,NewPath);
+  try
+    ZenFS.linkSync(lOld,lNew);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.RenameAt(OldFD: Integer; OldPath: String; NewFD: Integer;
+  NewPath: String): NativeInt;
+var
+  lOld,lNew : String;
+
+begin
+  lOld:=PrependFD(OldFD,OldPath);
+  lNew:=PrependFD(NewFD,NewPath);
+  try
+    ZenFS.renameSync(lOld,lNew);
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.SymLinkAt(FD: Integer; Path: String; Target: String
+  ): NativeInt;
+var
+  lPath : String;
+
+begin
+  lPath:=PrependFD(FD,Path);
+  try
+    ZenFS.symLinkSync(Target,lPath);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.Close(FD : Integer): NativeInt;
+
+begin
+  try
+    ZenFS.closeSync(fd);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.Write(FD: Integer; Data: TJSUint8Array; AtPos : Integer; out Written : Integer): NativeInt;
+
+var
+  DS : TJSDataView;
+
+begin
+  try
+    DS:=TJSDataView.New(Data.buffer);
+    if atPos<>-1 then
+      Written:=ZenFS.writeSync(fd,DS,atPos)
+    else
+      Written:=ZenFS.writeSync(fd,DS,0,Data.byteLength);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.Sync(FD: Integer): NativeInt;
+begin
+  try
+    ZenFS.fSyncSync(fd);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.DataSync(FD: Integer): NativeInt;
+begin
+  try
+    ZenFS.fdatasyncSync(fd);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.Seek(FD: integer; Offset: Integer; Whence: TSeekWhence; out
+  NewPos: Integer): NativeInt;
+
+var
+  aPos : Integer;
+  F : TZenFSFile;
+  Stat : TZenFSStats;
+
+begin
+  try
+    case whence of
+      swBeginning :
+        aPos:=AsIntNumber(OffSet);
+      swCurrent :
+        begin
+        // This is officially not supported...
+        F:=fd2file(fd);
+        if Assigned(F) then
+          aPos:=AsintNumber(F.Position)+AsIntNumber(Offset)
+        else
+          Raise TZenFSErrnoError.new(TZenFSErrNo.EBADF);
+        end;
+      swEnd :
+        begin
+        Stat:=ZenFS.fstatSync(fd);
+        aPos:=AsIntNumber(Stat.size)+AsIntNumber(Offset);
+        end;
+    end;
+//    Buf:=TJSDataView.New(TJSUint8Array.New(0));
+    ZenFS.readSync(fd,Nil,0,0,aPos);
+    NewPos:=aPos;
+    Result:=resOK;
+
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.Read(FD: Integer; Data: TJSUint8Array; AtPos: Integer; out
+  BytesRead: Integer): NativeInt;
+
+Var
+  V : TJSDataView;
+  opts : TZenFSReadSyncOptions;
+
+begin
+  V:=TJSDataView.new(Data.buffer);
+  try
+    opts:=TZenFSReadSyncOptions.new;
+    opts.offset:=0;
+    opts.length:=Data.byteLength;
+    if AtPos<>-1 then
+      opts.position:=AtPos;
+    BytesRead:=ZenFS.readSync(FD,V,Opts);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.GetPrestat(FD: Integer): String;
+begin
+  if (FD=3) then
+    begin
+    FRoot:=ZenFS.OpenDirSync('/');
+    Result:='/';
+    end;
+end;
+
+function TWASIZenFS.UnLinkAt(FD: Integer; const aPath: String): NativeInt;
+
+var
+  lPath : String;
+
+begin
+  lPath:=PrependFD(FD,aPath);
+  try
+    ZenFS.unlinkSync(lPath);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.OpenAt(FD : Integer; FDFlags : NativeInt; aPath : String; Flags, fsRightsBase, fsRightsInheriting, fsFlags: NativeInt; out Openfd: Integer): NativeInt;
+
+var
+  lPath : String;
+  lFlags : String;
+  Rights : NativeInt;
+  Reading,Writing : Boolean;
+
+  Function HasFlag(aFlag : Integer) : Boolean;
+  begin
+    Result:=(Flags and aFlag)<>0;
+  end;
+
+  Function HasRight(aRight : Integer) : Boolean;
+  begin
+    if IsBigint(Rights) then
+      begin
+      asm
+        Result = ((Rights & BigInt(aRight)) != 0)
+      end;
+      end
+    else
+      Result:=(Rights and aRight)<>0;
+  end;
+
+begin
+  if (fdFlags<>0) and (fsFlags<>0) then ;
+  lPath:=PrependFD(FD,aPath);
+  Rights:=AsIntNumber(fsRightsBase);
+  Writing:=HasFlag(__WASI_OFLAGS_CREAT) or HasRight(__WASI_RIGHTS_FD_WRITE);
+  Reading:=HasRight(__WASI_RIGHTS_FD_READ);
+  if Writing then
+    begin
+    if HasFlag(__WASI_OFLAGS_TRUNC) then
+      lFLags:='w'
+    else
+      lFLags:='a';
+    if HasFlag(__WASI_OFLAGS_EXCL) then
+      lFLags:=lFLags+'x';
+    if Reading then
+      lFLags:=lFLags+'+';
+    end
+  else
+    begin
+    lFlags:='r';
+    end;
+  try
+    OpenFD:=ZenFS.openSync(lPath,lFlags);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+function TWASIZenFS.ReadLinkAt(FD: Integer; aPath: String; out aTarget: String): NativeInt;
+
+var
+  lPath : String;
+
+begin
+  lPath:=PrependFD(FD,aPath);
+  try
+    aTarget:=ZenFS.readlinkSync(lPath);
+    Result:=resOK;
+  except
+    on E : TJSObject do
+      Result:=ExceptToError(E);
+  end;
+end;
+
+end.
+