1 files changed, 273 insertions, 0 deletions
diff --git a/libpod/oci.go b/libpod/oci.go
new file mode 100644
index 000000000..0ed1c1f66
--- /dev/null
+++ b/libpod/oci.go
@@ -0,0 +1,273 @@
+package libpod
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"github.com/containerd/cgroups"
+	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+
+	// TODO import these functions into libpod and remove the import
+	// Trying to keep libpod from depending on CRI-O code
+	"github.com/kubernetes-incubator/cri-o/utils"
+)
+
+// OCI code is undergoing heavy rewrite
+
+const (
+	// CgroupfsCgroupsManager represents cgroupfs native cgroup manager
+	CgroupfsCgroupsManager = "cgroupfs"
+	// SystemdCgroupsManager represents systemd native cgroup manager
+	SystemdCgroupsManager = "systemd"
+
+	// ContainerCreateTimeout represents the value of container creating timeout
+	ContainerCreateTimeout = 240 * time.Second
+)
+
+// OCIRuntime represents an OCI-compatible runtime that libpod can call into
+// to perform container operations
+type OCIRuntime struct {
+	name          string
+	path          string
+	conmonPath    string
+	conmonEnv     []string
+	cgroupManager string
+	tmpDir        string
+	exitsDir      string
+	socketsDir    string
+	logSizeMax    int64
+	noPivot       bool
+}
+
+// syncInfo is used to return data from monitor process to daemon
+type syncInfo struct {
+	Pid     int    `json:"pid"`
+	Message string `json:"message,omitempty"`
+}
+
+// Make a new OCI runtime with provided options
+func newOCIRuntime(name string, path string, conmonPath string, conmonEnv []string, cgroupManager string, tmpDir string, logSizeMax int64, noPivotRoot bool) (*OCIRuntime, error) {
+	runtime := new(OCIRuntime)
+	runtime.name = name
+	runtime.path = path
+	runtime.conmonPath = conmonPath
+	runtime.conmonEnv = conmonEnv
+	runtime.cgroupManager = cgroupManager
+	runtime.tmpDir = tmpDir
+	runtime.logSizeMax = logSizeMax
+	runtime.noPivot = noPivotRoot
+
+	runtime.exitsDir = filepath.Join(runtime.tmpDir, "exits")
+	runtime.socketsDir = filepath.Join(runtime.tmpDir, "socket")
+
+	if cgroupManager != CgroupfsCgroupsManager && cgroupManager != SystemdCgroupsManager {
+		return nil, errors.Wrapf(ErrInvalidArg, "invalid cgroup manager specified: %s", cgroupManager)
+	}
+
+	// Create the exit files and attach sockets directories
+	if err := os.MkdirAll(runtime.exitsDir, 0750); err != nil {
+		// The directory is allowed to exist
+		if !os.IsExist(err) {
+			return nil, errors.Wrapf(err, "error creating OCI runtime exit files directory %s",
+				runtime.exitsDir)
+		}
+	}
+	if err := os.MkdirAll(runtime.socketsDir, 0750); err != nil {
+		// The directory is allowed to exist
+		if !os.IsExist(err) {
+			return nil, errors.Wrapf(err, "error creating OCI runtime attach sockets directory %s",
+				runtime.socketsDir)
+		}
+	}
+
+	return runtime, nil
+}
+
+// newPipe creates a unix socket pair for communication
+func newPipe() (parent *os.File, child *os.File, err error) {
+	fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM|unix.SOCK_CLOEXEC, 0)
+	if err != nil {
+		return nil, nil, err
+	}
+	return os.NewFile(uintptr(fds[1]), "parent"), os.NewFile(uintptr(fds[0]), "child"), nil
+}
+
+// Create systemd unit name for cgroup scopes
+func createUnitName(prefix string, name string) string {
+	return fmt.Sprintf("%s-%s.scope", prefix, name)
+}
+
+// CreateContainer creates a container in the OCI runtime
+// TODO terminal support for container
+// Presently just ignoring conmon opts related to it
+func (r *OCIRuntime) createContainer(ctr *Container, cgroupParent string) error {
+	var stderrBuf bytes.Buffer
+
+	parentPipe, childPipe, err := newPipe()
+	if err != nil {
+		return errors.Wrapf(err, "error creating socket pair")
+	}
+
+	childStartPipe, parentStartPipe, err := newPipe()
+	if err != nil {
+		return errors.Wrapf(err, "error creating socket pair for start pipe")
+	}
+
+	defer parentPipe.Close()
+	defer parentStartPipe.Close()
+
+	args := []string{}
+	if r.cgroupManager == SystemdCgroupsManager {
+		args = append(args, "-s")
+	}
+	args = append(args, "-c", ctr.ID())
+	args = append(args, "-u", ctr.ID())
+	args = append(args, "-r", r.path)
+	args = append(args, "-b", ctr.bundlePath())
+	args = append(args, "-p", filepath.Join(ctr.state.RunDir, "pidfile"))
+	// TODO container log location should be configurable
+	// The default also likely shouldn't be this
+	args = append(args, "-l", filepath.Join(ctr.config.StaticDir, "ctr.log"))
+	args = append(args, "--exit-dir", r.exitsDir)
+	args = append(args, "--socket-dir-path", r.socketsDir)
+	if ctr.config.Spec.Process.Terminal {
+		args = append(args, "-t")
+	} else if ctr.config.Stdin {
+		args = append(args, "-i")
+	}
+	if r.logSizeMax >= 0 {
+		args = append(args, "--log-size-max", fmt.Sprintf("%v", r.logSizeMax))
+	}
+	if r.noPivot {
+		args = append(args, "--no-pivot")
+	}
+	logrus.WithFields(logrus.Fields{
+		"args": args,
+	}).Debugf("running conmon: %s", r.conmonPath)
+
+	cmd := exec.Command(r.conmonPath, args...)
+	cmd.Dir = ctr.state.RunDir
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setpgid: true,
+	}
+	// TODO this is probably a really bad idea for some uses
+	// Make this configurable
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if ctr.config.Spec.Process.Terminal {
+		cmd.Stderr = &stderrBuf
+	}
+
+	cmd.ExtraFiles = append(cmd.ExtraFiles, childPipe, childStartPipe)
+	// 0, 1 and 2 are stdin, stdout and stderr
+	cmd.Env = append(r.conmonEnv, fmt.Sprintf("_OCI_SYNCPIPE=%d", 3))
+	cmd.Env = append(cmd.Env, fmt.Sprintf("_OCI_STARTPIPE=%d", 4))
+
+	err = cmd.Start()
+	if err != nil {
+		childPipe.Close()
+		return err
+	}
+
+	// We don't need childPipe on the parent side
+	childPipe.Close()
+	childStartPipe.Close()
+
+	// Move conmon to specified cgroup
+	if r.cgroupManager == SystemdCgroupsManager {
+		logrus.Infof("Running conmon under slice %s and unitName %s", cgroupParent, createUnitName("libpod-conmon", ctr.ID()))
+		if err = utils.RunUnderSystemdScope(cmd.Process.Pid, cgroupParent, createUnitName("libpod-conmon", ctr.ID())); err != nil {
+			logrus.Warnf("Failed to add conmon to systemd sandbox cgroup: %v", err)
+		}
+	} else {
+		control, err := cgroups.New(cgroups.V1, cgroups.StaticPath(filepath.Join(cgroupParent, "/libpod-conmon-"+ctr.ID())), &spec.LinuxResources{})
+		if err != nil {
+			logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err)
+		} else {
+			// XXX: this defer does nothing as the cgroup can't be deleted cause
+			// it contains the conmon pid in tasks
+			// we need to remove this defer and delete the cgroup once conmon exits
+			// maybe need a conmon monitor?
+			defer control.Delete()
+			if err := control.Add(cgroups.Process{Pid: cmd.Process.Pid}); err != nil {
+				logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err)
+			}
+		}
+	}
+
+	/* We set the cgroup, now the child can start creating children */
+	someData := []byte{0}
+	_, err = parentStartPipe.Write(someData)
+	if err != nil {
+		return err
+	}
+
+	/* Wait for initial setup and fork, and reap child */
+	err = cmd.Wait()
+	if err != nil {
+		return err
+	}
+
+	// TODO should do a defer r.deleteContainer(ctr) here if err != nil
+	// Need deleteContainer to be working first, though...
+
+	// Wait to get container pid from conmon
+	type syncStruct struct {
+		si  *syncInfo
+		err error
+	}
+	ch := make(chan syncStruct)
+	go func() {
+		var si *syncInfo
+		if err = json.NewDecoder(parentPipe).Decode(&si); err != nil {
+			ch <- syncStruct{err: err}
+			return
+		}
+		ch <- syncStruct{si: si}
+	}()
+
+	select {
+	case ss := <-ch:
+		if ss.err != nil {
+			return errors.Wrapf(ss.err, "error reading container (probably exited) json message")
+		}
+		logrus.Debugf("Received container pid: %d", ss.si.Pid)
+		if ss.si.Pid == -1 {
+			if ss.si.Message != "" {
+				return errors.Wrapf(ErrInternal, "container create failed: %s", ss.si.Message)
+			}
+			return errors.Wrapf(ErrInternal, "container create failed")
+		}
+	case <-time.After(ContainerCreateTimeout):
+		return errors.Wrapf(ErrInternal, "container creation timeout")
+	}
+	return nil
+}
+
+// updateContainerStatus retrieves the current status of the container from the
+// runtime
+func (r *OCIRuntime) updateContainerStatus(ctr *Container) error {
+	return ErrNotImplemented
+}
+
+// startContainer starts the given container
+func (r *OCIRuntime) startContainer(ctr *Container) error {
+	// TODO: streams should probably *not* be our STDIN/OUT/ERR - redirect to buffers?
+	if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "start", ctr.ID()); err != nil {
+		return err
+	}
+
+	// TODO record start time in container struct
+
+	return nil
+}