Update gomod and vendor

vendor/github.com/containerd/go-runc/console.go

@@ -0,0 +1,165 @@
+// +build !windows
+
+/*
+   Copyright The containerd Authors.
+
+   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.
+*/
+
+package runc
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"path/filepath"
+
+	"github.com/containerd/console"
+	"golang.org/x/sys/unix"
+)
+
+// NewConsoleSocket creates a new unix socket at the provided path to accept a
+// pty master created by runc for use by the container
+func NewConsoleSocket(path string) (*Socket, error) {
+	abs, err := filepath.Abs(path)
+	if err != nil {
+		return nil, err
+	}
+	addr, err := net.ResolveUnixAddr("unix", abs)
+	if err != nil {
+		return nil, err
+	}
+	l, err := net.ListenUnix("unix", addr)
+	if err != nil {
+		return nil, err
+	}
+	return &Socket{
+		l: l,
+	}, nil
+}
+
+// NewTempConsoleSocket returns a temp console socket for use with a container
+// On Close(), the socket is deleted
+func NewTempConsoleSocket() (*Socket, error) {
+	runtimeDir := os.Getenv("XDG_RUNTIME_DIR")
+	dir, err := ioutil.TempDir(runtimeDir, "pty")
+	if err != nil {
+		return nil, err
+	}
+	abs, err := filepath.Abs(filepath.Join(dir, "pty.sock"))
+	if err != nil {
+		return nil, err
+	}
+	addr, err := net.ResolveUnixAddr("unix", abs)
+	if err != nil {
+		return nil, err
+	}
+	l, err := net.ListenUnix("unix", addr)
+	if err != nil {
+		return nil, err
+	}
+	if runtimeDir != "" {
+		if err := os.Chmod(abs, 0755|os.ModeSticky); err != nil {
+			return nil, err
+		}
+	}
+	return &Socket{
+		l:     l,
+		rmdir: true,
+	}, nil
+}
+
+// Socket is a unix socket that accepts the pty master created by runc
+type Socket struct {
+	rmdir bool
+	l     *net.UnixListener
+}
+
+// Path returns the path to the unix socket on disk
+func (c *Socket) Path() string {
+	return c.l.Addr().String()
+}
+
+// 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 *net.UnixConn) (*os.File, error) {
+	const MaxNameLen = 4096
+	var oobSpace = unix.CmsgSpace(4)
+
+	name := make([]byte, MaxNameLen)
+	oob := make([]byte, oobSpace)
+
+	n, oobn, _, _, err := socket.ReadMsgUnix(name, oob)
+	if err != nil {
+		return nil, err
+	}
+
+	if n >= MaxNameLen || oobn != oobSpace {
+		return nil, fmt.Errorf("recvfd: incorrect number of bytes read (n=%d oobn=%d)", n, oobn)
+	}
+
+	// Truncate.
+	name = name[:n]
+	oob = oob[:oobn]
+
+	scms, err := unix.ParseSocketControlMessage(oob)
+	if err != nil {
+		return nil, err
+	}
+	if len(scms) != 1 {
+		return nil, fmt.Errorf("recvfd: number of SCMs is not 1: %d", len(scms))
+	}
+	scm := scms[0]
+
+	fds, err := unix.ParseUnixRights(&scm)
+	if err != nil {
+		return nil, err
+	}
+	if len(fds) != 1 {
+		return nil, fmt.Errorf("recvfd: number of fds is not 1: %d", len(fds))
+	}
+	fd := uintptr(fds[0])
+
+	return os.NewFile(fd, string(name)), nil
+}
+
+// ReceiveMaster blocks until the socket receives the pty master
+func (c *Socket) ReceiveMaster() (console.Console, error) {
+	conn, err := c.l.Accept()
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+	uc, ok := conn.(*net.UnixConn)
+	if !ok {
+		return nil, fmt.Errorf("received connection which was not a unix socket")
+	}
+	f, err := recvFd(uc)
+	if err != nil {
+		return nil, err
+	}
+	return console.ConsoleFromFile(f)
+}
+
+// Close closes the unix socket
+func (c *Socket) Close() error {
+	err := c.l.Close()
+	if c.rmdir {
+		if rerr := os.RemoveAll(filepath.Dir(c.Path())); err == nil {
+			err = rerr
+		}
+	}
+	return err
+}