// on write calls.
//
//go:nowritebarrierrec
func write(fd uintptr, p unsafe.Pointer, n int32) int32 {
	if !(fd == 1 || fd == 2) {
		// Do an ordinary write.
		return write1(fd, p, n)
	}

	// Write with the playback header.

	// First, lock to avoid interleaving writes.
	lock(&faketimeState.lock)

	// If the current fd doesn't match the fd of the previous write,

}

func open(name string) (uintptr, error) {
	fd, err := syscall.Open(name, syscall.O_RDONLY)
	if err != nil {
		return 0, err
	}
	return uintptr(fd), nil
}

func read(fd uintptr, buf []byte) (int, error) {
	return syscall.Read(int(fd), buf)
}

func closefd(fd uintptr) {
	syscall.Close(int(fd))
}

func preadn(fd uintptr, buf []byte, off int) error {
	whence := seekStart
	if off < 0 {

//sys	Chroot(path string) (err error)
//sys	Close(fd int) (err error)
//sys	Dup(fd int) (nfd int, err error)
//sys	Dup2(from int, to int) (err error)
//sys	Fchdir(fd int) (err error)
//sys	Fchflags(fd int, flags int) (err error)
//sys	Fchmod(fd int, mode uint32) (err error)
//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Flock(fd int, how int) (err error)
//sys	Fpathconf(fd int, name int) (val int, err error)

	if err != nil {
		fmt.Printf("ReadAll from fd 3: %v\n", err)
		os.Exit(1)
	}

	// Now verify that there are no other open fds.
	// stdin == 0
	// stdout == 1
	// stderr == 2
	// descriptor from parent == 3
	// All descriptors 4 and up should be available,
	// except for any used by the network poller.
	for fd := uintptr(4); fd <= 100; fd++ {
		if poll.IsPollDescriptor(fd) {
			continue
		}

//sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Fstat(fd int, stat *Stat_t) (err error)
//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_NEWFSTATAT
//sys	Fstatfs(fd int, buf *Statfs_t) (err error)
//sys	Ftruncate(fd int, length int64) (err error)
//sysnb	Getegid() (egid int)

//sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Fstat(fd int, stat *Stat_t) (err error)
//sys	Fstatat(fd int, path string, stat *Stat_t, flags int) (err error)
//sys	Fstatfs(fd int, buf *Statfs_t) (err error)
//sys	Ftruncate(fd int, length int64) (err error)
//sysnb	Getegid() (egid int)

	if d == 0 {
		d = defaultTCPKeepAliveInterval
	} else if d < 0 {
		return nil
	}

	// The kernel expects seconds so round to next highest second.
	secs := int(roundDurationUp(d, time.Second))
	err := fd.pfd.SetsockoptInt(syscall.IPPROTO_TCP, syscall.TCP_KEEPINTVL, secs)
	runtime.KeepAlive(fd)
	return wrapSyscallError("setsockopt", err)
}

	if c.fd.isConnected && addr != nil {
		return 0, 0, ErrWriteToConnected
	}
	if !c.fd.isConnected && addr == nil {
		return 0, 0, errMissingAddress
	}
	sa, err := addr.sockaddr(c.fd.family)
	if err != nil {
		return 0, 0, err
	}
	return c.fd.writeMsg(b, oob, sa)
}

func (c *UDPConn) writeMsgAddrPort(b, oob []byte, addr netip.AddrPort) (n, oobn int, err error) {
	if c.fd.isConnected && addr.IsValid() {

// Implemented in assembly to avoid allocation.
func seek(fd int, offset int64, whence int) (newoffset int64, err Errno)

func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
	newoffset, errno := seek(fd, offset, whence)
	if errno != 0 {
		return 0, errno
	}
	return newoffset, nil
}

//sys	accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error)

}

func (fd *netFD) netFD() (*netFD, error) {
	return newFD(fd.net, fd.n, fd.listen, fd.ctl, fd.data, fd.laddr, fd.raddr)
}

func (fd *netFD) acceptPlan9() (nfd *netFD, err error) {
	defer func() { fixErr(err) }()
	if err := fd.pfd.ReadLock(); err != nil {
		return nil, err
	}
	defer fd.pfd.ReadUnlock()
	listen, err := os.Open(fd.dir + "/listen")
	if err != nil {
		return nil, err