Replace execdrivers with containerd implementation

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
Signed-off-by: Anusha Ragunathan <anusha@docker.com>
Upstream-commit: 9c4570a958df42d1ad19364b1a8da55b891d850a
Component: engine

components/engine/libcontainerd/process_linux.go

@@ -0,0 +1,107 @@
+package libcontainerd
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	containerd "github.com/docker/containerd/api/grpc/types"
+	"github.com/docker/docker/pkg/ioutils"
+	"golang.org/x/net/context"
+)
+
+var fdNames = map[int]string{
+	syscall.Stdin:  "stdin",
+	syscall.Stdout: "stdout",
+	syscall.Stderr: "stderr",
+}
+
+// process keeps the state for both main container process and exec process.
+type process struct {
+	processCommon
+
+	// Platform specific fields are below here.
+	dir string
+}
+
+func (p *process) openFifos(terminal bool) (*IOPipe, error) {
+	bundleDir := p.dir
+	if err := os.MkdirAll(bundleDir, 0700); err != nil {
+		return nil, err
+	}
+
+	for i := 0; i < 3; i++ {
+		f := p.fifo(i)
+		if err := syscall.Mkfifo(f, 0700); err != nil && !os.IsExist(err) {
+			return nil, fmt.Errorf("mkfifo: %s %v", f, err)
+		}
+	}
+
+	io := &IOPipe{}
+	stdinf, err := os.OpenFile(p.fifo(syscall.Stdin), syscall.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	io.Stdout = openReaderFromFifo(p.fifo(syscall.Stdout))
+	if !terminal {
+		io.Stderr = openReaderFromFifo(p.fifo(syscall.Stderr))
+	} else {
+		io.Stderr = emptyReader{}
+	}
+
+	io.Stdin = ioutils.NewWriteCloserWrapper(stdinf, func() error {
+		stdinf.Close()
+		_, err := p.client.remote.apiClient.UpdateProcess(context.Background(), &containerd.UpdateProcessRequest{
+			Id:         p.containerID,
+			Pid:        p.friendlyName,
+			CloseStdin: true,
+		})
+		return err
+	})
+
+	return io, nil
+}
+
+func (p *process) closeFifos(io *IOPipe) {
+	io.Stdin.Close()
+	closeReaderFifo(p.fifo(syscall.Stdout))
+	closeReaderFifo(p.fifo(syscall.Stderr))
+}
+
+type emptyReader struct{}
+
+func (r emptyReader) Read(b []byte) (int, error) {
+	return 0, io.EOF
+}
+
+func openReaderFromFifo(fn string) io.Reader {
+	r, w := io.Pipe()
+	go func() {
+		stdoutf, err := os.OpenFile(fn, syscall.O_RDONLY, 0)
+		if err != nil {
+			r.CloseWithError(err)
+		}
+		if _, err := io.Copy(w, stdoutf); err != nil {
+			r.CloseWithError(err)
+		}
+		w.Close()
+		stdoutf.Close()
+	}()
+	return r
+}
+
+// closeReaderFifo closes fifo that may be blocked on open by opening the write side.
+func closeReaderFifo(fn string) {
+	f, err := os.OpenFile(fn, syscall.O_WRONLY|syscall.O_NONBLOCK, 0)
+	if err != nil {
+		return
+	}
+	f.Close()
+}
+
+func (p *process) fifo(index int) string {
+	return filepath.Join(p.dir, p.friendlyName+"-"+fdNames[index])
+}