Refactor runtime code for code sharing

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

pkg/process/utils.go

@@ -0,0 +1,192 @@
+// +build !windows
+
+/*
+   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 process
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/containerd/containerd/errdefs"
+	runc "github.com/containerd/go-runc"
+	"github.com/pkg/errors"
+	"golang.org/x/sys/unix"
+)
+
+const (
+	// RuncRoot is the path to the root runc state directory
+	RuncRoot = "/run/containerd/runc"
+	// StoppedPID is the pid assigned after a container has run and stopped
+	StoppedPID = -1
+	// InitPidFile name of the file that contains the init pid
+	InitPidFile = "init.pid"
+)
+
+// safePid is a thread safe wrapper for pid.
+type safePid struct {
+	sync.Mutex
+	pid int
+}
+
+func (s *safePid) get() int {
+	s.Lock()
+	defer s.Unlock()
+	return s.pid
+}
+
+func (s *safePid) set(pid int) {
+	s.Lock()
+	s.pid = pid
+	s.Unlock()
+}
+
+// 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
+	}
+	defer f.Close()
+
+	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()
+
+	p := bufPool.Get().(*[]byte)
+	defer bufPool.Put(p)
+	_, err = io.CopyBuffer(tt, ff, *p)
+	return err
+}
+
+func checkKillError(err error) error {
+	if err == nil {
+		return nil
+	}
+	if strings.Contains(err.Error(), "os: process already finished") ||
+		strings.Contains(err.Error(), "container not running") ||
+		err == unix.ESRCH {
+		return errors.Wrapf(errdefs.ErrNotFound, "process already finished")
+	}
+	return errors.Wrapf(err, "unknown error after kill")
+}
+
+func newPidFile(bundle string) *pidFile {
+	return &pidFile{
+		path: filepath.Join(bundle, InitPidFile),
+	}
+}
+
+func newExecPidFile(bundle, id string) *pidFile {
+	return &pidFile{
+		path: filepath.Join(bundle, fmt.Sprintf("%s.pid", id)),
+	}
+}
+
+type pidFile struct {
+	path string
+}
+
+func (p *pidFile) Path() string {
+	return p.path
+}
+
+func (p *pidFile) Read() (int, error) {
+	return runc.ReadPidFile(p.path)
+}
+
+// waitTimeout handles waiting on a waitgroup with a specified timeout.
+// this is commonly used for waiting on IO to finish after a process has exited
+func waitTimeout(ctx context.Context, wg *sync.WaitGroup, timeout time.Duration) error {
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+	done := make(chan struct{}, 1)
+	go func() {
+		wg.Wait()
+		close(done)
+	}()
+	select {
+	case <-done:
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
+func stateName(v interface{}) string {
+	switch v.(type) {
+	case *runningState, *execRunningState:
+		return "running"
+	case *createdState, *execCreatedState, *createdCheckpointState:
+		return "created"
+	case *pausedState:
+		return "paused"
+	case *deletedState:
+		return "deleted"
+	case *stoppedState:
+		return "stopped"
+	}
+	panic(errors.Errorf("invalid state %v", v))
+}