return syscall.Read(syscall.Handle(fd), buf)
}

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

func preadn(fd uintptr, buf []byte, off int) error {
	whence := seekStart
	if off < 0 {
		whence = seekEnd
	}
	if _, err := syscall.Seek(syscall.Handle(fd), int64(off), whence); err != nil {
		return err
	}
	for len(buf) > 0 {
		m, err := syscall.Read(syscall.Handle(fd), buf)

		syscall.RTM_ADD:        rtm,
		syscall.RTM_DELETE:     rtm,
		syscall.RTM_CHANGE:     rtm,
		syscall.RTM_GET:        rtm,
		syscall.RTM_LOSING:     rtm,
		syscall.RTM_REDIRECT:   rtm,
		syscall.RTM_MISS:       rtm,
		syscall.RTM_RESOLVE:    rtm,
		syscall.RTM_NEWADDR:    ifam,
		syscall.RTM_DELADDR:    ifam,
		syscall.RTM_IFINFO:     ifm,
		syscall.RTM_IFANNOUNCE: ifanm,

		syscall.RTM_CHANGE:     rtm,
		syscall.RTM_GET:        rtm,
		syscall.RTM_LOSING:     rtm,
		syscall.RTM_REDIRECT:   rtm,
		syscall.RTM_MISS:       rtm,
		syscall.RTM_LOCK:       rtm,
		syscall.RTM_RESOLVE:    rtm,
		syscall.RTM_NEWADDR:    ifam,
		syscall.RTM_DELADDR:    ifam,
		syscall.RTM_IFINFO:     ifm,
		syscall.RTM_NEWMADDR:   ifmam,
		syscall.RTM_DELMADDR:   ifmam,
		syscall.RTM_IFANNOUNCE: ifanm,
	}

	switch fs.sys.Mode & syscall.S_IFMT {
	case syscall.S_IFBLK:
		fs.mode |= ModeDevice
	case syscall.S_IFCHR:
		fs.mode |= ModeDevice | ModeCharDevice
	case syscall.S_IFDIR:
		fs.mode |= ModeDir
	case syscall.S_IFIFO:
		fs.mode |= ModeNamedPipe
	case syscall.S_IFLNK:
		fs.mode |= ModeSymlink
	case syscall.S_IFREG:
		// nothing to do
	case syscall.S_IFSOCK:
		fs.mode |= ModeSocket

		fs.mode |= ModeDir
	case syscall.S_IFIFO:
		fs.mode |= ModeNamedPipe
	case syscall.S_IFLNK:
		fs.mode |= ModeSymlink
	case syscall.S_IFREG:
		// nothing to do
	case syscall.S_IFSOCK:
		fs.mode |= ModeSocket
	}
	if fs.sys.Mode&syscall.S_ISGID != 0 {
		fs.mode |= ModeSetgid
	}
	if fs.sys.Mode&syscall.S_ISUID != 0 {
		fs.mode |= ModeSetuid
	}
	if fs.sys.Mode&syscall.S_ISVTX != 0 {
		fs.mode |= ModeSticky
	}

		fs.mode |= ModeDir
	case syscall.S_IFIFO:
		fs.mode |= ModeNamedPipe
	case syscall.S_IFLNK:
		fs.mode |= ModeSymlink
	case syscall.S_IFREG:
		// nothing to do
	case syscall.S_IFSOCK:
		fs.mode |= ModeSocket
	}
	if fs.sys.Mode&syscall.S_ISGID != 0 {
		fs.mode |= ModeSetgid
	}
	if fs.sys.Mode&syscall.S_ISUID != 0 {
		fs.mode |= ModeSetuid
	}
	if fs.sys.Mode&syscall.S_ISVTX != 0 {
		fs.mode |= ModeSticky

			//   IPv4-embedded IPv6 addresses.
			if addr.IP.To16() != nil && addr.IP.To4() == nil {
				operr = syscall.SetsockoptInt(syscall.Handle(s), syscall.IPPROTO_IPV6, syscall.IPV6_UNICAST_HOPS, 1)
			} else if addr.IP.To16() == nil && addr.IP.To4() != nil {
				operr = syscall.SetsockoptInt(syscall.Handle(s), syscall.IPPROTO_IP, syscall.IP_TTL, 1)
			}
		}
	}
	if err := c.Control(fn); err != nil {
		return err
	}
	return operr
}

package net

import (
	"os"
	"syscall"
	"testing"
)

func TestSpuriousENOTAVAIL(t *testing.T) {
	for _, tt := range []struct {
		error
		ok bool
	}{
		{syscall.EADDRNOTAVAIL, true},
		{&os.SyscallError{Syscall: "syscall", Err: syscall.EADDRNOTAVAIL}, true},
		{&OpError{Op: "op", Err: syscall.EADDRNOTAVAIL}, true},
		{&OpError{Op: "op", Err: &os.SyscallError{Syscall: "syscall", Err: syscall.EADDRNOTAVAIL}}, true},

		fallthrough
	case syscall.O_RDWR | syscall.O_CREAT:
		lockType |= syscall.LOCK_EX
	default:
		return nil, &os.PathError{
			Op:   "open",
			Path: path,
			Err:  syscall.EINVAL,
		}
	}

	f, err := os.OpenFile(path, flag|syscall.O_SYNC, perm)
	if err != nil {
		return nil, err
	}

	if err = syscall.Flock(int(f.Fd()), lockType); err != nil {
		f.Close()
		if err == syscall.EWOULDBLOCK {
			err = ErrAlreadyLocked

				_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_KEEPCNT, 5)

				// Wait time after successful probe in seconds.
				// ~ cat /proc/sys/net/ipv4/tcp_keepalive_intvl (defaults to 75 secs, we reduce it to 15 secs)
				_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_KEEPINTVL, 15)
			}