runsc: Terminal support for "docker exec -ti".

This CL adds terminal support for "docker exec".  We previously only supported
consoles for the container process, but not exec processes.

The SYS_IOCTL syscall was added to the default seccomp filter list, but only
for ioctls that get/set winsize and termios structs. We need to allow these
ioctl for all containers because it's possible to run "exec -ti" on a
container that was started without an attached console, after the filters
have been installed.

Note that control-character signals are still not properly supported.

Tested with:
	$ docker run --runtime=runsc -it alpine
In another terminial:
	$ docker exec -it <containerid> /bin/sh

PiperOrigin-RevId: 210185456
Change-Id: I6d2401e53a7697bb988c120a8961505c335f96d9

1 files changed, 0 insertions, 60 deletions

diff --git a/runsc/sandbox/console.go b/runsc/sandbox/console.go
deleted file mode 100644
index 3f133e12a..000000000
--- a/runsc/sandbox/console.go
+++ /dev/null
@@ -1,60 +0,0 @@
-// Copyright 2018 Google Inc.
-//
-// 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 sandbox
-
-import (
-	"fmt"
-	"net"
-	"os"
-
-	"github.com/kr/pty"
-	"golang.org/x/sys/unix"
-)
-
-// setupConsole creates pty master/slave pair, sends the master FD over the
-// given socket, and returns the slave.
-func setupConsole(socketPath string) (*os.File, error) {
-	// Create a new pty master and slave.
-	ptyMaster, ptySlave, err := pty.Open()
-	if err != nil {
-		return nil, fmt.Errorf("error opening pty: %v", err)
-	}
-	defer ptyMaster.Close()
-
-	// Get a connection to the socket path.
-	conn, err := net.Dial("unix", socketPath)
-	if err != nil {
-		ptySlave.Close()
-		return nil, fmt.Errorf("error dial socket %q: %v", socketPath, err)
-	}
-	uc, ok := conn.(*net.UnixConn)
-	if !ok {
-		ptySlave.Close()
-		return nil, fmt.Errorf("connection is not a UnixConn: %T", conn)
-	}
-	socket, err := uc.File()
-	if err != nil {
-		ptySlave.Close()
-		return nil, fmt.Errorf("error getting file for unix socket %v: %v", uc, err)
-	}
-
-	// Send the master FD over the connection.
-	msg := unix.UnixRights(int(ptyMaster.Fd()))
-	if err := unix.Sendmsg(int(socket.Fd()), []byte("pty-master"), msg, nil, 0); err != nil {
-		ptySlave.Close()
-		return nil, fmt.Errorf("error sending console over unix socket %q: %v", socketPath, err)
-	}
-	return ptySlave, nil
-}