// The net argument is a network name from the net package (e.g., "tcp"),
// or "file".
// Set pollable to true if fd should be managed by runtime netpoll.
func (fd *FD) Init(net string, pollable bool) error {
	fd.SysFile.init()

	// We don't actually care about the various network types.
	if net == "file" {
		fd.isFile = true
	}
	if !pollable {
		fd.isBlocking = 1
		return nil
	}
	err := fd.pd.init(fd)
	if err != nil {

				pollable = false
			}

			// In addition to the behavior described above for regular files,
			// on Darwin, kqueue does not work properly with fifos:
			// closing the last writer does not cause a kqueue event
			// for any readers. See issue #24164.
			if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && typ == syscall.S_IFIFO {
				pollable = false
			}
		}
	}

	return os.OpenFile("/dev/net/tun", os.O_RDWR, 0)
}

func isBadStateFileError(err error) (string, bool) {
	switch err {
	case poll.ErrNotPollable, syscall.EBADFD:
		return "", true
	default:
		return "not pollable or file in bad state error", false
	}

	if err := fd.incref(); err != nil {
		return 0, err
	}
	defer fd.decref()
	for {
		n, err := ignoringEINTRIO(syscall.ReadDirent, fd.Sysfd, buf)
		if err != nil {
			n = 0
			if err == syscall.EAGAIN && fd.pd.pollable() {
				if err = fd.pd.waitRead(fd.isFile); err == nil {
					continue
				}
			}
		}
		// Do not call eofError; caller does not expect to see io.EOF.
		return n, err
	}
}

// Seek wraps syscall.Seek.

func (pd *pollDesc) waitWrite(isFile bool) error { return pd.wait('w', isFile) }

func (pd *pollDesc) waitCanceled(mode int) {}

func (pd *pollDesc) pollable() bool { return true }

// SetDeadline sets the read and write deadlines associated with fd.
func (fd *FD) SetDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'r'+'w')
}

// Issue #59545.
func TestNonPollable(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping test with tight loops in short mode")
	}

	// We need to open a non-pollable file.
	// This is almost certainly Linux-specific,
	// but if other systems have non-pollable files,
	// we can add them here.
	const nonPollable = "/dev/net/tun"

	f, err := os.OpenFile(nonPollable, os.O_RDWR, 0)
	if err != nil {

		n, err := splice(pipefd, sock.Sysfd, max, spliceNonblock)
		if err == syscall.EINTR {
			continue
		}
		if err != syscall.EAGAIN {
			return n, err
		}
		if sock.pd.pollable() {
			if err := sock.pd.waitRead(sock.isFile); err != nil {
				return n, err
			}
		}
	}
}

// splicePump moves all the buffered data from a pipe to a socket.
//

func (e *DeadlineExceededError) Temporary() bool { return true }

// ErrNotPollable is returned when the file or socket is not suitable
// for event notification.
var ErrNotPollable = errors.New("not pollable")

// consume removes data from a slice of byte slices, for writev.
func consume(v *[][]byte, n int64) {
	for len(*v) > 0 {
		ln0 := int64(len((*v)[0]))
		if ln0 > n {
			(*v)[0] = (*v)[0][n:]
			return
		}

	/* 19 */ {_SigNotify, "SIGPWR: power-fail restart"},
	/* 20 */ {_SigNotify + _SigIgn, "SIGWINCH: window size change"},
	/* 21 */ {_SigNotify + _SigIgn, "SIGURG: urgent socket condition"},
	/* 22 */ {_SigNotify, "SIGPOLL: pollable event occurred"},
	/* 23 */ {0, "SIGSTOP: stop (cannot be caught or ignored)"},
	/* 24 */ {_SigNotify + _SigDefault + _SigIgn, "SIGTSTP: user stop requested from tty"},

	return pd.wait('w', isFile)
}

func (pd *pollDesc) waitCanceled(mode int) {
	if pd.runtimeCtx == 0 {
		return
	}
	runtime_pollWaitCanceled(pd.runtimeCtx, mode)
}

func (pd *pollDesc) pollable() bool {
	return pd.runtimeCtx != 0
}

// Error values returned by runtime_pollReset and runtime_pollWait.
// These must match the values in runtime/netpoll.go.
const (
	pollNoError        = 0