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- // Copyright 2018 The Go Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE file.
- //go:build js && wasm
- package syscall
- import (
- "errors"
- "sync"
- "syscall/js"
- )
- // Provided by package runtime.
- func now() (sec int64, nsec int32)
- var jsProcess = js.Global().Get("process")
- var jsFS = js.Global().Get("fs")
- var constants = jsFS.Get("constants")
- var uint8Array = js.Global().Get("Uint8Array")
- var (
- nodeWRONLY = constants.Get("O_WRONLY").Int()
- nodeRDWR = constants.Get("O_RDWR").Int()
- nodeCREATE = constants.Get("O_CREAT").Int()
- nodeTRUNC = constants.Get("O_TRUNC").Int()
- nodeAPPEND = constants.Get("O_APPEND").Int()
- nodeEXCL = constants.Get("O_EXCL").Int()
- )
- type jsFile struct {
- path string
- entries []string
- dirIdx int // entries[:dirIdx] have already been returned in ReadDirent
- pos int64
- seeked bool
- }
- var filesMu sync.Mutex
- var files = map[int]*jsFile{
- 0: {},
- 1: {},
- 2: {},
- }
- func fdToFile(fd int) (*jsFile, error) {
- filesMu.Lock()
- f, ok := files[fd]
- filesMu.Unlock()
- if !ok {
- return nil, EBADF
- }
- return f, nil
- }
- func Open(path string, openmode int, perm uint32) (int, error) {
- if err := checkPath(path); err != nil {
- return 0, err
- }
- flags := 0
- if openmode&O_WRONLY != 0 {
- flags |= nodeWRONLY
- }
- if openmode&O_RDWR != 0 {
- flags |= nodeRDWR
- }
- if openmode&O_CREATE != 0 {
- flags |= nodeCREATE
- }
- if openmode&O_TRUNC != 0 {
- flags |= nodeTRUNC
- }
- if openmode&O_APPEND != 0 {
- flags |= nodeAPPEND
- }
- if openmode&O_EXCL != 0 {
- flags |= nodeEXCL
- }
- if openmode&O_SYNC != 0 {
- return 0, errors.New("syscall.Open: O_SYNC is not supported by js/wasm")
- }
- jsFD, err := fsCall("open", path, flags, perm)
- if err != nil {
- return 0, err
- }
- fd := jsFD.Int()
- var entries []string
- if stat, err := fsCall("fstat", fd); err == nil && stat.Call("isDirectory").Bool() {
- dir, err := fsCall("readdir", path)
- if err != nil {
- return 0, err
- }
- entries = make([]string, dir.Length())
- for i := range entries {
- entries[i] = dir.Index(i).String()
- }
- }
- if path[0] != '/' {
- cwd := jsProcess.Call("cwd").String()
- path = cwd + "/" + path
- }
- f := &jsFile{
- path: path,
- entries: entries,
- }
- filesMu.Lock()
- files[fd] = f
- filesMu.Unlock()
- return fd, nil
- }
- func Close(fd int) error {
- filesMu.Lock()
- delete(files, fd)
- filesMu.Unlock()
- _, err := fsCall("close", fd)
- return err
- }
- func CloseOnExec(fd int) {
- // nothing to do - no exec
- }
- func Mkdir(path string, perm uint32) error {
- if err := checkPath(path); err != nil {
- return err
- }
- _, err := fsCall("mkdir", path, perm)
- return err
- }
- func ReadDirent(fd int, buf []byte) (int, error) {
- f, err := fdToFile(fd)
- if err != nil {
- return 0, err
- }
- if f.entries == nil {
- return 0, EINVAL
- }
- n := 0
- for f.dirIdx < len(f.entries) {
- entry := f.entries[f.dirIdx]
- l := 2 + len(entry)
- if l > len(buf) {
- break
- }
- buf[0] = byte(l)
- buf[1] = byte(l >> 8)
- copy(buf[2:], entry)
- buf = buf[l:]
- n += l
- f.dirIdx++
- }
- return n, nil
- }
- func setStat(st *Stat_t, jsSt js.Value) {
- st.Dev = int64(jsSt.Get("dev").Int())
- st.Ino = uint64(jsSt.Get("ino").Int())
- st.Mode = uint32(jsSt.Get("mode").Int())
- st.Nlink = uint32(jsSt.Get("nlink").Int())
- st.Uid = uint32(jsSt.Get("uid").Int())
- st.Gid = uint32(jsSt.Get("gid").Int())
- st.Rdev = int64(jsSt.Get("rdev").Int())
- st.Size = int64(jsSt.Get("size").Int())
- st.Blksize = int32(jsSt.Get("blksize").Int())
- st.Blocks = int32(jsSt.Get("blocks").Int())
- atime := int64(jsSt.Get("atimeMs").Int())
- st.Atime = atime / 1000
- st.AtimeNsec = (atime % 1000) * 1000000
- mtime := int64(jsSt.Get("mtimeMs").Int())
- st.Mtime = mtime / 1000
- st.MtimeNsec = (mtime % 1000) * 1000000
- ctime := int64(jsSt.Get("ctimeMs").Int())
- st.Ctime = ctime / 1000
- st.CtimeNsec = (ctime % 1000) * 1000000
- }
- func Stat(path string, st *Stat_t) error {
- if err := checkPath(path); err != nil {
- return err
- }
- jsSt, err := fsCall("stat", path)
- if err != nil {
- return err
- }
- setStat(st, jsSt)
- return nil
- }
- func Lstat(path string, st *Stat_t) error {
- if err := checkPath(path); err != nil {
- return err
- }
- jsSt, err := fsCall("lstat", path)
- if err != nil {
- return err
- }
- setStat(st, jsSt)
- return nil
- }
- func Fstat(fd int, st *Stat_t) error {
- jsSt, err := fsCall("fstat", fd)
- if err != nil {
- return err
- }
- setStat(st, jsSt)
- return nil
- }
- func Unlink(path string) error {
- if err := checkPath(path); err != nil {
- return err
- }
- _, err := fsCall("unlink", path)
- return err
- }
- func Rmdir(path string) error {
- if err := checkPath(path); err != nil {
- return err
- }
- _, err := fsCall("rmdir", path)
- return err
- }
- func Chmod(path string, mode uint32) error {
- if err := checkPath(path); err != nil {
- return err
- }
- _, err := fsCall("chmod", path, mode)
- return err
- }
- func Fchmod(fd int, mode uint32) error {
- _, err := fsCall("fchmod", fd, mode)
- return err
- }
- func Chown(path string, uid, gid int) error {
- if err := checkPath(path); err != nil {
- return err
- }
- _, err := fsCall("chown", path, uint32(uid), uint32(gid))
- return err
- }
- func Fchown(fd int, uid, gid int) error {
- _, err := fsCall("fchown", fd, uint32(uid), uint32(gid))
- return err
- }
- func Lchown(path string, uid, gid int) error {
- if err := checkPath(path); err != nil {
- return err
- }
- if jsFS.Get("lchown").IsUndefined() {
- // fs.lchown is unavailable on Linux until Node.js 10.6.0
- // TODO(neelance): remove when we require at least this Node.js version
- return ENOSYS
- }
- _, err := fsCall("lchown", path, uint32(uid), uint32(gid))
- return err
- }
- func UtimesNano(path string, ts []Timespec) error {
- if err := checkPath(path); err != nil {
- return err
- }
- if len(ts) != 2 {
- return EINVAL
- }
- atime := ts[0].Sec
- mtime := ts[1].Sec
- _, err := fsCall("utimes", path, atime, mtime)
- return err
- }
- func Rename(from, to string) error {
- if err := checkPath(from); err != nil {
- return err
- }
- if err := checkPath(to); err != nil {
- return err
- }
- _, err := fsCall("rename", from, to)
- return err
- }
- func Truncate(path string, length int64) error {
- if err := checkPath(path); err != nil {
- return err
- }
- _, err := fsCall("truncate", path, length)
- return err
- }
- func Ftruncate(fd int, length int64) error {
- _, err := fsCall("ftruncate", fd, length)
- return err
- }
- func Getcwd(buf []byte) (n int, err error) {
- defer recoverErr(&err)
- cwd := jsProcess.Call("cwd").String()
- n = copy(buf, cwd)
- return
- }
- func Chdir(path string) (err error) {
- if err := checkPath(path); err != nil {
- return err
- }
- defer recoverErr(&err)
- jsProcess.Call("chdir", path)
- return
- }
- func Fchdir(fd int) error {
- f, err := fdToFile(fd)
- if err != nil {
- return err
- }
- return Chdir(f.path)
- }
- func Readlink(path string, buf []byte) (n int, err error) {
- if err := checkPath(path); err != nil {
- return 0, err
- }
- dst, err := fsCall("readlink", path)
- if err != nil {
- return 0, err
- }
- n = copy(buf, dst.String())
- return n, nil
- }
- func Link(path, link string) error {
- if err := checkPath(path); err != nil {
- return err
- }
- if err := checkPath(link); err != nil {
- return err
- }
- _, err := fsCall("link", path, link)
- return err
- }
- func Symlink(path, link string) error {
- if err := checkPath(path); err != nil {
- return err
- }
- if err := checkPath(link); err != nil {
- return err
- }
- _, err := fsCall("symlink", path, link)
- return err
- }
- func Fsync(fd int) error {
- _, err := fsCall("fsync", fd)
- return err
- }
- func Read(fd int, b []byte) (int, error) {
- f, err := fdToFile(fd)
- if err != nil {
- return 0, err
- }
- if f.seeked {
- n, err := Pread(fd, b, f.pos)
- f.pos += int64(n)
- return n, err
- }
- buf := uint8Array.New(len(b))
- n, err := fsCall("read", fd, buf, 0, len(b), nil)
- if err != nil {
- return 0, err
- }
- js.CopyBytesToGo(b, buf)
- n2 := n.Int()
- f.pos += int64(n2)
- return n2, err
- }
- func Write(fd int, b []byte) (int, error) {
- f, err := fdToFile(fd)
- if err != nil {
- return 0, err
- }
- if f.seeked {
- n, err := Pwrite(fd, b, f.pos)
- f.pos += int64(n)
- return n, err
- }
- if faketime && (fd == 1 || fd == 2) {
- n := faketimeWrite(fd, b)
- if n < 0 {
- return 0, errnoErr(Errno(-n))
- }
- return n, nil
- }
- buf := uint8Array.New(len(b))
- js.CopyBytesToJS(buf, b)
- n, err := fsCall("write", fd, buf, 0, len(b), nil)
- if err != nil {
- return 0, err
- }
- n2 := n.Int()
- f.pos += int64(n2)
- return n2, err
- }
- func Pread(fd int, b []byte, offset int64) (int, error) {
- buf := uint8Array.New(len(b))
- n, err := fsCall("read", fd, buf, 0, len(b), offset)
- if err != nil {
- return 0, err
- }
- js.CopyBytesToGo(b, buf)
- return n.Int(), nil
- }
- func Pwrite(fd int, b []byte, offset int64) (int, error) {
- buf := uint8Array.New(len(b))
- js.CopyBytesToJS(buf, b)
- n, err := fsCall("write", fd, buf, 0, len(b), offset)
- if err != nil {
- return 0, err
- }
- return n.Int(), nil
- }
- func Seek(fd int, offset int64, whence int) (int64, error) {
- f, err := fdToFile(fd)
- if err != nil {
- return 0, err
- }
- var newPos int64
- switch whence {
- case 0:
- newPos = offset
- case 1:
- newPos = f.pos + offset
- case 2:
- var st Stat_t
- if err := Fstat(fd, &st); err != nil {
- return 0, err
- }
- newPos = st.Size + offset
- default:
- return 0, errnoErr(EINVAL)
- }
- if newPos < 0 {
- return 0, errnoErr(EINVAL)
- }
- f.seeked = true
- f.dirIdx = 0 // Reset directory read position. See issue 35767.
- f.pos = newPos
- return newPos, nil
- }
- func Dup(fd int) (int, error) {
- return 0, ENOSYS
- }
- func Dup2(fd, newfd int) error {
- return ENOSYS
- }
- func Pipe(fd []int) error {
- return ENOSYS
- }
- func fsCall(name string, args ...any) (js.Value, error) {
- type callResult struct {
- val js.Value
- err error
- }
- c := make(chan callResult, 1)
- f := js.FuncOf(func(this js.Value, args []js.Value) any {
- var res callResult
- if len(args) >= 1 { // on Node.js 8, fs.utimes calls the callback without any arguments
- if jsErr := args[0]; !jsErr.IsNull() {
- res.err = mapJSError(jsErr)
- }
- }
- res.val = js.Undefined()
- if len(args) >= 2 {
- res.val = args[1]
- }
- c <- res
- return nil
- })
- defer f.Release()
- jsFS.Call(name, append(args, f)...)
- res := <-c
- return res.val, res.err
- }
- // checkPath checks that the path is not empty and that it contains no null characters.
- func checkPath(path string) error {
- if path == "" {
- return EINVAL
- }
- for i := 0; i < len(path); i++ {
- if path[i] == '\x00' {
- return EINVAL
- }
- }
- return nil
- }
- func recoverErr(errPtr *error) {
- if err := recover(); err != nil {
- jsErr, ok := err.(js.Error)
- if !ok {
- panic(err)
- }
- *errPtr = mapJSError(jsErr.Value)
- }
- }
- // mapJSError maps an error given by Node.js to the appropriate Go error
- func mapJSError(jsErr js.Value) error {
- errno, ok := errnoByCode[jsErr.Get("code").String()]
- if !ok {
- panic(jsErr)
- }
- return errnoErr(Errno(errno))
- }
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