Update runc to ce450bcc6c135cae93ee2a99d41a308c179ff6dc

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

vendor/github.com/opencontainers/runc/libcontainer/utils/cmsg.go

@@ -0,0 +1,57 @@
+// +build linux
+
+package utils
+
+/*
+ * Copyright 2016 SUSE LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+#include <errno.h>
+#include <stdlib.h>
+#include "cmsg.h"
+*/
+import "C"
+
+import (
+	"os"
+	"unsafe"
+)
+
+// RecvFd waits for a file descriptor to be sent over the given AF_UNIX
+// socket. The file name of the remote file descriptor will be recreated
+// locally (it is sent as non-auxiliary data in the same payload).
+func RecvFd(socket *os.File) (*os.File, error) {
+	file, err := C.recvfd(C.int(socket.Fd()))
+	if err != nil {
+		return nil, err
+	}
+	defer C.free(unsafe.Pointer(file.name))
+	return os.NewFile(uintptr(file.fd), C.GoString(file.name)), nil
+}
+
+// SendFd sends a file descriptor over the given AF_UNIX socket. In
+// addition, the file.Name() of the given file will also be sent as
+// non-auxiliary data in the same payload (allowing to send contextual
+// information for a file descriptor).
+func SendFd(socket, file *os.File) error {
+	var cfile C.struct_file_t
+	cfile.fd = C.int(file.Fd())
+	cfile.name = C.CString(file.Name())
+	defer C.free(unsafe.Pointer(cfile.name))
+
+	_, err := C.sendfd(C.int(socket.Fd()), cfile)
+	return err
+}