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// +build linux
package main
import (
"fmt"
"io"
"os"
"os/signal"
"sync"
"github.com/containerd/console"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runc/libcontainer/utils"
)
type tty struct {
epoller *console.Epoller
console *console.EpollConsole
stdin console.Console
closers []io.Closer
postStart []io.Closer
wg sync.WaitGroup
consoleC chan error
}
func (t *tty) copyIO(w io.Writer, r io.ReadCloser) {
defer t.wg.Done()
io.Copy(w, r)
r.Close()
}
// setup pipes for the process so that advanced features like c/r are able to easily checkpoint
// and restore the process's IO without depending on a host specific path or device
func setupProcessPipes(p *libcontainer.Process, rootuid, rootgid int) (*tty, error) {
i, err := p.InitializeIO(rootuid, rootgid)
if err != nil {
return nil, err
}
t := &tty{
closers: []io.Closer{
i.Stdin,
i.Stdout,
i.Stderr,
},
}
// add the process's io to the post start closers if they support close
for _, cc := range []interface{}{
p.Stdin,
p.Stdout,
p.Stderr,
} {
if c, ok := cc.(io.Closer); ok {
t.postStart = append(t.postStart, c)
}
}
go func() {
io.Copy(i.Stdin, os.Stdin)
i.Stdin.Close()
}()
t.wg.Add(2)
go t.copyIO(os.Stdout, i.Stdout)
go t.copyIO(os.Stderr, i.Stderr)
return t, nil
}
func inheritStdio(process *libcontainer.Process) error {
process.Stdin = os.Stdin
process.Stdout = os.Stdout
process.Stderr = os.Stderr
return nil
}
func (t *tty) recvtty(process *libcontainer.Process, socket *os.File) error {
f, err := utils.RecvFd(socket)
if err != nil {
return err
}
cons, err := console.ConsoleFromFile(f)
if err != nil {
return err
}
console.ClearONLCR(cons.Fd())
epoller, err := console.NewEpoller()
if err != nil {
return err
}
epollConsole, err := epoller.Add(cons)
if err != nil {
return err
}
go epoller.Wait()
go io.Copy(epollConsole, os.Stdin)
t.wg.Add(1)
go t.copyIO(os.Stdout, epollConsole)
// set raw mode to stdin and also handle interrupt
stdin, err := console.ConsoleFromFile(os.Stdin)
if err != nil {
return err
}
if err := stdin.SetRaw(); err != nil {
return fmt.Errorf("failed to set the terminal from the stdin: %v", err)
}
go handleInterrupt(stdin)
t.epoller = epoller
t.stdin = stdin
t.console = epollConsole
t.closers = []io.Closer{epollConsole}
return nil
}
func handleInterrupt(c console.Console) {
sigchan := make(chan os.Signal, 1)
signal.Notify(sigchan, os.Interrupt)
<-sigchan
c.Reset()
os.Exit(0)
}
func (t *tty) waitConsole() error {
if t.consoleC != nil {
return <-t.consoleC
}
return nil
}
// ClosePostStart closes any fds that are provided to the container and dup2'd
// so that we no longer have copy in our process.
func (t *tty) ClosePostStart() error {
for _, c := range t.postStart {
c.Close()
}
return nil
}
// Close closes all open fds for the tty and/or restores the orignal
// stdin state to what it was prior to the container execution
func (t *tty) Close() error {
// ensure that our side of the fds are always closed
for _, c := range t.postStart {
c.Close()
}
// the process is gone at this point, shutting down the console if we have
// one and wait for all IO to be finished
if t.console != nil && t.epoller != nil {
t.console.Shutdown(t.epoller.CloseConsole)
}
t.wg.Wait()
for _, c := range t.closers {
c.Close()
}
if t.stdin != nil {
t.stdin.Reset()
}
return nil
}
func (t *tty) resize() error {
if t.console == nil {
return nil
}
return t.console.ResizeFrom(console.Current())
}