ctr: move shim to commands

Signed-off-by: Jess Valarezo <valarezo.jessica@gmail.com>

cmd/ctr/commands/shim/io_windows.go

@@ -0,0 +1,91 @@
+package shim
+
+import (
+	"io"
+	"net"
+	"os"
+	"sync"
+
+	"github.com/Microsoft/go-winio"
+	clog "github.com/containerd/containerd/log"
+	"github.com/pkg/errors"
+)
+
+func prepareStdio(stdin, stdout, stderr string, console bool) (*sync.WaitGroup, error) {
+	var wg sync.WaitGroup
+
+	if stdin != "" {
+		l, err := winio.ListenPipe(stdin, nil)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to create stdin pipe %s", stdin)
+		}
+		defer func(l net.Listener) {
+			if err != nil {
+				l.Close()
+			}
+		}(l)
+
+		go func() {
+			c, err := l.Accept()
+			if err != nil {
+				clog.L.WithError(err).Errorf("failed to accept stdin connection on %s", stdin)
+				return
+			}
+			io.Copy(c, os.Stdin)
+			c.Close()
+			l.Close()
+		}()
+	}
+
+	if stdout != "" {
+		l, err := winio.ListenPipe(stdout, nil)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to create stdin pipe %s", stdout)
+		}
+		defer func(l net.Listener) {
+			if err != nil {
+				l.Close()
+			}
+		}(l)
+
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			c, err := l.Accept()
+			if err != nil {
+				clog.L.WithError(err).Errorf("failed to accept stdout connection on %s", stdout)
+				return
+			}
+			io.Copy(os.Stdout, c)
+			c.Close()
+			l.Close()
+		}()
+	}
+
+	if !console && stderr != "" {
+		l, err := winio.ListenPipe(stderr, nil)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to create stderr pipe %s", stderr)
+		}
+		defer func(l net.Listener) {
+			if err != nil {
+				l.Close()
+			}
+		}(l)
+
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			c, err := l.Accept()
+			if err != nil {
+				clog.L.WithError(err).Errorf("failed to accept stderr connection on %s", stderr)
+				return
+			}
+			io.Copy(os.Stderr, c)
+			c.Close()
+			l.Close()
+		}()
+	}
+
+	return &wg, nil
+}