mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
e57b2a8066
Signed-off-by: John Howard <jhoward@microsoft.com>
165 lines
3.8 KiB
Go
165 lines
3.8 KiB
Go
// +build !windows
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/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package runc
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import (
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"fmt"
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"io/ioutil"
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"net"
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"os"
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"path/filepath"
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"github.com/containerd/console"
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"golang.org/x/sys/unix"
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)
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// NewConsoleSocket creates a new unix socket at the provided path to accept a
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// pty master created by runc for use by the container
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func NewConsoleSocket(path string) (*Socket, error) {
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abs, err := filepath.Abs(path)
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if err != nil {
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return nil, err
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}
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addr, err := net.ResolveUnixAddr("unix", abs)
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if err != nil {
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return nil, err
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}
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l, err := net.ListenUnix("unix", addr)
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if err != nil {
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return nil, err
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}
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return &Socket{
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l: l,
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}, nil
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}
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// NewTempConsoleSocket returns a temp console socket for use with a container
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// On Close(), the socket is deleted
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func NewTempConsoleSocket() (*Socket, error) {
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runtimeDir := os.Getenv("XDG_RUNTIME_DIR")
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dir, err := ioutil.TempDir(runtimeDir, "pty")
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if err != nil {
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return nil, err
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}
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abs, err := filepath.Abs(filepath.Join(dir, "pty.sock"))
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if err != nil {
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return nil, err
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}
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addr, err := net.ResolveUnixAddr("unix", abs)
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if err != nil {
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return nil, err
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}
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l, err := net.ListenUnix("unix", addr)
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if err != nil {
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return nil, err
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}
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if runtimeDir != "" {
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if err := os.Chmod(abs, 0755|os.ModeSticky); err != nil {
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return nil, err
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}
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}
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return &Socket{
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l: l,
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rmdir: true,
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}, nil
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}
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// Socket is a unix socket that accepts the pty master created by runc
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type Socket struct {
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rmdir bool
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l *net.UnixListener
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}
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// Path returns the path to the unix socket on disk
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func (c *Socket) Path() string {
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return c.l.Addr().String()
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}
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// recvFd waits for a file descriptor to be sent over the given AF_UNIX
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// socket. The file name of the remote file descriptor will be recreated
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// locally (it is sent as non-auxiliary data in the same payload).
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func recvFd(socket *net.UnixConn) (*os.File, error) {
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const MaxNameLen = 4096
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var oobSpace = unix.CmsgSpace(4)
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name := make([]byte, MaxNameLen)
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oob := make([]byte, oobSpace)
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n, oobn, _, _, err := socket.ReadMsgUnix(name, oob)
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if err != nil {
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return nil, err
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}
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if n >= MaxNameLen || oobn != oobSpace {
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return nil, fmt.Errorf("recvfd: incorrect number of bytes read (n=%d oobn=%d)", n, oobn)
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}
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// Truncate.
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name = name[:n]
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oob = oob[:oobn]
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scms, err := unix.ParseSocketControlMessage(oob)
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if err != nil {
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return nil, err
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}
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if len(scms) != 1 {
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return nil, fmt.Errorf("recvfd: number of SCMs is not 1: %d", len(scms))
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}
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scm := scms[0]
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fds, err := unix.ParseUnixRights(&scm)
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if err != nil {
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return nil, err
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}
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if len(fds) != 1 {
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return nil, fmt.Errorf("recvfd: number of fds is not 1: %d", len(fds))
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}
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fd := uintptr(fds[0])
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return os.NewFile(fd, string(name)), nil
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}
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// ReceiveMaster blocks until the socket receives the pty master
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func (c *Socket) ReceiveMaster() (console.Console, error) {
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conn, err := c.l.Accept()
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if err != nil {
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return nil, err
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}
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defer conn.Close()
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uc, ok := conn.(*net.UnixConn)
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if !ok {
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return nil, fmt.Errorf("received connection which was not a unix socket")
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}
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f, err := recvFd(uc)
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if err != nil {
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return nil, err
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}
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return console.ConsoleFromFile(f)
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}
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// Close closes the unix socket
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func (c *Socket) Close() error {
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err := c.l.Close()
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if c.rmdir {
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if rerr := os.RemoveAll(filepath.Dir(c.Path())); err == nil {
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err = rerr
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}
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}
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return err
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}
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