Add containerd shim v2 support. (#13)

* Update vendors

Signed-off-by: Lantao Liu <lantaol@google.com>

* Add containerd shim v2 support.

Signed-off-by: Lantao Liu <lantaol@google.com>

* Add test and doc for containerd-shim-runsc-v1.

Signed-off-by: Lantao Liu <lantaol@google.com>

* Address comments.

1 files changed, 111 insertions, 0 deletions

diff --git a/pkg/v2/service_linux.go b/pkg/v2/service_linux.go
new file mode 100644
index 000000000..cbd431537
--- /dev/null
+++ b/pkg/v2/service_linux.go
@@ -0,0 +1,111 @@
+/*
+   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 v2
+
+import (
+	"context"
+	"io"
+	"sync"
+	"syscall"
+
+	"github.com/containerd/console"
+	"github.com/containerd/fifo"
+	"github.com/pkg/errors"
+)
+
+type linuxPlatform struct {
+	epoller *console.Epoller
+}
+
+func (p *linuxPlatform) CopyConsole(ctx context.Context, console console.Console, stdin, stdout, stderr string, wg, cwg *sync.WaitGroup) (console.Console, error) {
+	if p.epoller == nil {
+		return nil, errors.New("uninitialized epoller")
+	}
+
+	epollConsole, err := p.epoller.Add(console)
+	if err != nil {
+		return nil, err
+	}
+
+	if stdin != "" {
+		in, err := fifo.OpenFifo(context.Background(), stdin, syscall.O_RDONLY|syscall.O_NONBLOCK, 0)
+		if err != nil {
+			return nil, err
+		}
+		cwg.Add(1)
+		go func() {
+			cwg.Done()
+			p := bufPool.Get().(*[]byte)
+			defer bufPool.Put(p)
+			io.CopyBuffer(epollConsole, in, *p)
+		}()
+	}
+
+	outw, err := fifo.OpenFifo(ctx, stdout, syscall.O_WRONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	outr, err := fifo.OpenFifo(ctx, stdout, syscall.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	wg.Add(1)
+	cwg.Add(1)
+	go func() {
+		cwg.Done()
+		p := bufPool.Get().(*[]byte)
+		defer bufPool.Put(p)
+		io.CopyBuffer(outw, epollConsole, *p)
+		epollConsole.Close()
+		outr.Close()
+		outw.Close()
+		wg.Done()
+	}()
+	return epollConsole, nil
+}
+
+func (p *linuxPlatform) ShutdownConsole(ctx context.Context, cons console.Console) error {
+	if p.epoller == nil {
+		return errors.New("uninitialized epoller")
+	}
+	epollConsole, ok := cons.(*console.EpollConsole)
+	if !ok {
+		return errors.Errorf("expected EpollConsole, got %#v", cons)
+	}
+	return epollConsole.Shutdown(p.epoller.CloseConsole)
+}
+
+func (p *linuxPlatform) Close() error {
+	return p.epoller.Close()
+}
+
+// initialize a single epoll fd to manage our consoles. `initPlatform` should
+// only be called once.
+func (s *service) initPlatform() error {
+	if s.platform != nil {
+		return nil
+	}
+	epoller, err := console.NewEpoller()
+	if err != nil {
+		return errors.Wrap(err, "failed to initialize epoller")
+	}
+	s.platform = &linuxPlatform{
+		epoller: epoller,
+	}
+	go epoller.Wait()
+	return nil
+}