fix #102 - add windows support

vendor/golang.org/x/sys/unix/sockcmsg_unix.go

@@ -9,9 +9,35 @@
 package unix
 
 import (
+	"runtime"
 	"unsafe"
 )
 
+// Round the length of a raw sockaddr up to align it properly.
+func cmsgAlignOf(salen int) int {
+	salign := SizeofPtr
+
+	switch runtime.GOOS {
+	case "aix":
+		// There is no alignment on AIX.
+		salign = 1
+	case "darwin", "dragonfly", "solaris", "illumos":
+		// NOTE: It seems like 64-bit Darwin, DragonFly BSD,
+		// illumos, and Solaris kernels still require 32-bit
+		// aligned access to network subsystem.
+		if SizeofPtr == 8 {
+			salign = 4
+		}
+	case "netbsd", "openbsd":
+		// NetBSD and OpenBSD armv7 require 64-bit alignment.
+		if runtime.GOARCH == "arm" {
+			salign = 8
+		}
+	}
+
+	return (salen + salign - 1) & ^(salign - 1)
+}
+
 // CmsgLen returns the value to store in the Len field of the Cmsghdr
 // structure, taking into account any necessary alignment.
 func CmsgLen(datalen int) int {
@@ -24,8 +50,8 @@ func CmsgSpace(datalen int) int {
 	return cmsgAlignOf(SizeofCmsghdr) + cmsgAlignOf(datalen)
 }
 
-func (h *Cmsghdr) data(offset uintptr) unsafe.Pointer {
-	return unsafe.Pointer(uintptr(unsafe.Pointer(h)) + uintptr(cmsgAlignOf(SizeofCmsghdr)) + offset)
+func cmsgData(h *Cmsghdr) unsafe.Pointer {
+	return unsafe.Pointer(uintptr(unsafe.Pointer(h)) + uintptr(cmsgAlignOf(SizeofCmsghdr)))
 }
 
 // SocketControlMessage represents a socket control message.
@@ -68,8 +94,10 @@ func UnixRights(fds ...int) []byte {
 	h.Level = SOL_SOCKET
 	h.Type = SCM_RIGHTS
 	h.SetLen(CmsgLen(datalen))
-	for i, fd := range fds {
-		*(*int32)(h.data(4 * uintptr(i))) = int32(fd)
+	data := cmsgData(h)
+	for _, fd := range fds {
+		*(*int32)(data) = int32(fd)
+		data = unsafe.Pointer(uintptr(data) + 4)
 	}
 	return b
 }