Move shim process code to package

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

linux/proc/utils.go

@@ -0,0 +1,86 @@
+// +build !windows
+
+package proc
+
+import (
+	"encoding/json"
+	"io"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/containerd/containerd/errdefs"
+	shimapi "github.com/containerd/containerd/linux/shim/v1"
+	runc "github.com/containerd/go-runc"
+	"github.com/pkg/errors"
+	"golang.org/x/sys/unix"
+)
+
+// TODO(mlaventure): move to runc package?
+func getLastRuntimeError(r *runc.Runc) (string, error) {
+	if r.Log == "" {
+		return "", nil
+	}
+
+	f, err := os.OpenFile(r.Log, os.O_RDONLY, 0400)
+	if err != nil {
+		return "", err
+	}
+
+	var (
+		errMsg string
+		log    struct {
+			Level string
+			Msg   string
+			Time  time.Time
+		}
+	)
+
+	dec := json.NewDecoder(f)
+	for err = nil; err == nil; {
+		if err = dec.Decode(&log); err != nil && err != io.EOF {
+			return "", err
+		}
+		if log.Level == "error" {
+			errMsg = strings.TrimSpace(log.Msg)
+		}
+	}
+
+	return errMsg, nil
+}
+
+// criuError returns only the first line of the error message from criu
+// it tries to add an invalid dump log location when returning the message
+func criuError(err error) string {
+	parts := strings.Split(err.Error(), "\n")
+	return parts[0]
+}
+
+func copyFile(to, from string) error {
+	ff, err := os.Open(from)
+	if err != nil {
+		return err
+	}
+	defer ff.Close()
+	tt, err := os.Create(to)
+	if err != nil {
+		return err
+	}
+	defer tt.Close()
+	_, err = io.Copy(tt, ff)
+	return err
+}
+
+func checkKillError(err error) error {
+	if err == nil {
+		return nil
+	}
+	if strings.Contains(err.Error(), "os: process already finished") || err == unix.ESRCH {
+		return errors.Wrapf(errdefs.ErrNotFound, "process already finished")
+	}
+	return errors.Wrapf(err, "unknown error after kill")
+}
+
+func hasNoIO(r *shimapi.CreateTaskRequest) bool {
+	return r.Stdin == "" && r.Stdout == "" && r.Stderr == ""
+}