Move OCI runtime implementation behind an interface

For future work, we need multiple implementations of the OCI
runtime, not just a Conmon-wrapped runtime matching the runc CLI.

As part of this, do some refactoring on the interface for exec
(move to a struct, not a massive list of arguments). Also, add
'all' support to Kill and Stop (supported by runc and used a bit
internally for removing containers).

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 1421 insertions, 0 deletions

diff --git a/libpod/oci_conmon_linux.go b/libpod/oci_conmon_linux.go
new file mode 100644
index 000000000..f29758a69
--- /dev/null
+++ b/libpod/oci_conmon_linux.go
@@ -0,0 +1,1421 @@
+// +build linux
+
+package libpod
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/containers/libpod/libpod/define"
+	"github.com/containers/libpod/pkg/cgroups"
+	"github.com/containers/libpod/pkg/errorhandling"
+	"github.com/containers/libpod/pkg/lookup"
+	"github.com/containers/libpod/pkg/rootless"
+	"github.com/containers/libpod/pkg/util"
+	"github.com/containers/libpod/utils"
+	pmount "github.com/containers/storage/pkg/mount"
+	"github.com/coreos/go-systemd/activation"
+	spec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/opencontainers/selinux/go-selinux"
+	"github.com/opencontainers/selinux/go-selinux/label"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+)
+
+// ConmonOCIRuntime is an OCI runtime managed by Conmon.
+// TODO: Make all calls to OCI runtime have a timeout.
+type ConmonOCIRuntime struct {
+	name              string
+	path              string
+	conmonPath        string
+	conmonEnv         []string
+	cgroupManager     string
+	tmpDir            string
+	exitsDir          string
+	socketsDir        string
+	logSizeMax        int64
+	noPivot           bool
+	reservePorts      bool
+	supportsJSON      bool
+	supportsNoCgroups bool
+	sdNotify          bool
+}
+
+// Make a new Conmon-based OCI runtime with the given options.
+// Conmon will wrap the given OCI runtime, which can be `runc`, `crun`, or
+// any runtime with a runc-compatible CLI.
+// The first path that points to a valid executable will be used.
+// Deliberately private. Someone should not be able to construct this outside of
+// libpod.
+func newConmonOCIRuntime(name string, paths []string, conmonPath string, runtimeCfg *RuntimeConfig, supportsJSON, supportsNoCgroups bool) (OCIRuntime, error) {
+	if name == "" {
+		return nil, errors.Wrapf(define.ErrInvalidArg, "the OCI runtime must be provided a non-empty name")
+	}
+
+	runtime := new(ConmonOCIRuntime)
+	runtime.name = name
+	runtime.conmonPath = conmonPath
+
+	runtime.conmonEnv = runtimeCfg.ConmonEnvVars
+	runtime.cgroupManager = runtimeCfg.CgroupManager
+	runtime.tmpDir = runtimeCfg.TmpDir
+	runtime.logSizeMax = runtimeCfg.MaxLogSize
+	runtime.noPivot = runtimeCfg.NoPivotRoot
+	runtime.reservePorts = runtimeCfg.EnablePortReservation
+	runtime.sdNotify = runtimeCfg.SDNotify
+
+	// TODO: probe OCI runtime for feature and enable automatically if
+	// available.
+	runtime.supportsJSON = supportsJSON
+	runtime.supportsNoCgroups = supportsNoCgroups
+
+	foundPath := false
+	for _, path := range paths {
+		stat, err := os.Stat(path)
+		if err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+			return nil, errors.Wrapf(err, "cannot stat %s", path)
+		}
+		if !stat.Mode().IsRegular() {
+			continue
+		}
+		foundPath = true
+		runtime.path = path
+		logrus.Debugf("using runtime %q", path)
+		break
+	}
+
+	// Search the $PATH as last fallback
+	if !foundPath {
+		if foundRuntime, err := exec.LookPath(name); err == nil {
+			foundPath = true
+			runtime.path = foundRuntime
+			logrus.Debugf("using runtime %q from $PATH: %q", name, foundRuntime)
+		}
+	}
+
+	if !foundPath {
+		return nil, errors.Wrapf(define.ErrInvalidArg, "no valid executable found for OCI runtime %s", name)
+	}
+
+	runtime.exitsDir = filepath.Join(runtime.tmpDir, "exits")
+	runtime.socketsDir = filepath.Join(runtime.tmpDir, "socket")
+
+	if runtime.cgroupManager != CgroupfsCgroupsManager && runtime.cgroupManager != SystemdCgroupsManager {
+		return nil, errors.Wrapf(define.ErrInvalidArg, "invalid cgroup manager specified: %s", runtime.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
+}
+
+// Name returns the name of the runtime being wrapped by Conmon.
+func (r *ConmonOCIRuntime) Name() string {
+	return r.name
+}
+
+// Path returns the path of the OCI runtime being wrapped by Conmon.
+func (r *ConmonOCIRuntime) Path() string {
+	return r.path
+}
+
+// CreateContainer creates a container.
+func (r *ConmonOCIRuntime) CreateContainer(ctr *Container, restoreOptions *ContainerCheckpointOptions) (err error) {
+	if len(ctr.config.IDMappings.UIDMap) != 0 || len(ctr.config.IDMappings.GIDMap) != 0 {
+		for _, i := range []string{ctr.state.RunDir, ctr.runtime.config.TmpDir, ctr.config.StaticDir, ctr.state.Mountpoint, ctr.runtime.config.VolumePath} {
+			if err := makeAccessible(i, ctr.RootUID(), ctr.RootGID()); err != nil {
+				return err
+			}
+		}
+
+		// if we are running a non privileged container, be sure to umount some kernel paths so they are not
+		// bind mounted inside the container at all.
+		if !ctr.config.Privileged && !rootless.IsRootless() {
+			ch := make(chan error)
+			go func() {
+				runtime.LockOSThread()
+				err := func() error {
+					fd, err := os.Open(fmt.Sprintf("/proc/%d/task/%d/ns/mnt", os.Getpid(), unix.Gettid()))
+					if err != nil {
+						return err
+					}
+					defer errorhandling.CloseQuiet(fd)
+
+					// create a new mountns on the current thread
+					if err = unix.Unshare(unix.CLONE_NEWNS); err != nil {
+						return err
+					}
+					defer func() {
+						if err := unix.Setns(int(fd.Fd()), unix.CLONE_NEWNS); err != nil {
+							logrus.Errorf("unable to clone new namespace: %q", err)
+						}
+					}()
+
+					// don't spread our mounts around.  We are setting only /sys to be slave
+					// so that the cleanup process is still able to umount the storage and the
+					// changes are propagated to the host.
+					err = unix.Mount("/sys", "/sys", "none", unix.MS_REC|unix.MS_SLAVE, "")
+					if err != nil {
+						return errors.Wrapf(err, "cannot make /sys slave")
+					}
+
+					mounts, err := pmount.GetMounts()
+					if err != nil {
+						return err
+					}
+					for _, m := range mounts {
+						if !strings.HasPrefix(m.Mountpoint, "/sys/kernel") {
+							continue
+						}
+						err = unix.Unmount(m.Mountpoint, 0)
+						if err != nil && !os.IsNotExist(err) {
+							return errors.Wrapf(err, "cannot unmount %s", m.Mountpoint)
+						}
+					}
+					return r.createOCIContainer(ctr, restoreOptions)
+				}()
+				ch <- err
+			}()
+			err := <-ch
+			return err
+		}
+	}
+	return r.createOCIContainer(ctr, restoreOptions)
+}
+
+// UpdateContainerStatus retrieves the current status of the container from the
+// runtime. It updates the container's state but does not save it.
+// If useRuntime is false, we will not directly hit runc to see the container's
+// status, but will instead only check for the existence of the conmon exit file
+// and update state to stopped if it exists.
+func (r *ConmonOCIRuntime) UpdateContainerStatus(ctr *Container, useRuntime bool) error {
+	exitFile, err := ctr.exitFilePath()
+	if err != nil {
+		return err
+	}
+
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return err
+	}
+
+	// If not using the OCI runtime, we don't need to do most of this.
+	if !useRuntime {
+		// If the container's not running, nothing to do.
+		if ctr.state.State != define.ContainerStateRunning && ctr.state.State != define.ContainerStatePaused {
+			return nil
+		}
+
+		// Check for the exit file conmon makes
+		info, err := os.Stat(exitFile)
+		if err != nil {
+			if os.IsNotExist(err) {
+				// Container is still running, no error
+				return nil
+			}
+
+			return errors.Wrapf(err, "error running stat on container %s exit file", ctr.ID())
+		}
+
+		// Alright, it exists. Transition to Stopped state.
+		ctr.state.State = define.ContainerStateStopped
+		ctr.state.PID = 0
+		ctr.state.ConmonPID = 0
+
+		// Read the exit file to get our stopped time and exit code.
+		return ctr.handleExitFile(exitFile, info)
+	}
+
+	// Store old state so we know if we were already stopped
+	oldState := ctr.state.State
+
+	state := new(spec.State)
+
+	cmd := exec.Command(r.path, "state", ctr.ID())
+	cmd.Env = append(cmd.Env, fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir))
+
+	outPipe, err := cmd.StdoutPipe()
+	if err != nil {
+		return errors.Wrapf(err, "getting stdout pipe")
+	}
+	errPipe, err := cmd.StderrPipe()
+	if err != nil {
+		return errors.Wrapf(err, "getting stderr pipe")
+	}
+
+	if err := cmd.Start(); err != nil {
+		out, err2 := ioutil.ReadAll(errPipe)
+		if err2 != nil {
+			return errors.Wrapf(err, "error getting container %s state", ctr.ID())
+		}
+		if strings.Contains(string(out), "does not exist") {
+			if err := ctr.removeConmonFiles(); err != nil {
+				logrus.Debugf("unable to remove conmon files for container %s", ctr.ID())
+			}
+			ctr.state.ExitCode = -1
+			ctr.state.FinishedTime = time.Now()
+			ctr.state.State = define.ContainerStateExited
+			return nil
+		}
+		return errors.Wrapf(err, "error getting container %s state. stderr/out: %s", ctr.ID(), out)
+	}
+	defer func() {
+		_ = cmd.Wait()
+	}()
+
+	if err := errPipe.Close(); err != nil {
+		return err
+	}
+	out, err := ioutil.ReadAll(outPipe)
+	if err != nil {
+		return errors.Wrapf(err, "error reading stdout: %s", ctr.ID())
+	}
+	if err := json.NewDecoder(bytes.NewBuffer(out)).Decode(state); err != nil {
+		return errors.Wrapf(err, "error decoding container status for container %s", ctr.ID())
+	}
+	ctr.state.PID = state.Pid
+
+	switch state.Status {
+	case "created":
+		ctr.state.State = define.ContainerStateCreated
+	case "paused":
+		ctr.state.State = define.ContainerStatePaused
+	case "running":
+		ctr.state.State = define.ContainerStateRunning
+	case "stopped":
+		ctr.state.State = define.ContainerStateStopped
+	default:
+		return errors.Wrapf(define.ErrInternal, "unrecognized status returned by runtime for container %s: %s",
+			ctr.ID(), state.Status)
+	}
+
+	// Only grab exit status if we were not already stopped
+	// If we were, it should already be in the database
+	if ctr.state.State == define.ContainerStateStopped && oldState != define.ContainerStateStopped {
+		var fi os.FileInfo
+		chWait := make(chan error)
+		defer close(chWait)
+
+		_, err := WaitForFile(exitFile, chWait, time.Second*5)
+		if err == nil {
+			fi, err = os.Stat(exitFile)
+		}
+		if err != nil {
+			ctr.state.ExitCode = -1
+			ctr.state.FinishedTime = time.Now()
+			logrus.Errorf("No exit file for container %s found: %v", ctr.ID(), err)
+			return nil
+		}
+
+		return ctr.handleExitFile(exitFile, fi)
+	}
+
+	return nil
+}
+
+// StartContainer starts the given container.
+// Sets time the container was started, but does not save it.
+func (r *ConmonOCIRuntime) StartContainer(ctr *Container) error {
+	// TODO: streams should probably *not* be our STDIN/OUT/ERR - redirect to buffers?
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return err
+	}
+	env := []string{fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir)}
+	if notify, ok := os.LookupEnv("NOTIFY_SOCKET"); ok {
+		env = append(env, fmt.Sprintf("NOTIFY_SOCKET=%s", notify))
+	}
+	if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, env, r.path, "start", ctr.ID()); err != nil {
+		return err
+	}
+
+	ctr.state.StartedTime = time.Now()
+
+	return nil
+}
+
+// KillContainer sends the given signal to the given container.
+// If all is set, send to all PIDs in the container.
+// All is only supported if the container created cgroups.
+func (r *ConmonOCIRuntime) KillContainer(ctr *Container, signal uint, all bool) error {
+	logrus.Debugf("Sending signal %d to container %s", signal, ctr.ID())
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return err
+	}
+	env := []string{fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir)}
+	var args []string
+	if all {
+		args = []string{"kill", "--all", ctr.ID(), fmt.Sprintf("%d", signal)}
+	} else {
+		args = []string{"kill", ctr.ID(), fmt.Sprintf("%d", signal)}
+	}
+	if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, env, r.path, args...); err != nil {
+		return errors.Wrapf(err, "error sending signal to container %s", ctr.ID())
+	}
+
+	return nil
+}
+
+// StopContainer stops a container, first using its given stop signal (or
+// SIGTERM if no signal was specified), then using SIGKILL.
+// Timeout is given in seconds. If timeout is 0, the container will be
+// immediately kill with SIGKILL.
+// Does not set finished time for container, assumes you will run updateStatus
+// after to pull the exit code.
+func (r *ConmonOCIRuntime) StopContainer(ctr *Container, timeout uint, all bool) error {
+	logrus.Debugf("Stopping container %s (PID %d)", ctr.ID(), ctr.state.PID)
+
+	// Ping the container to see if it's alive
+	// If it's not, it's already stopped, return
+	err := unix.Kill(ctr.state.PID, 0)
+	if err == unix.ESRCH {
+		return nil
+	}
+
+	stopSignal := ctr.config.StopSignal
+	if stopSignal == 0 {
+		stopSignal = uint(syscall.SIGTERM)
+	}
+
+	if timeout > 0 {
+		if err := r.KillContainer(ctr, stopSignal, all); err != nil {
+			// Is the container gone?
+			// If so, it probably died between the first check and
+			// our sending the signal
+			// The container is stopped, so exit cleanly
+			err := unix.Kill(ctr.state.PID, 0)
+			if err == unix.ESRCH {
+				return nil
+			}
+
+			return err
+		}
+
+		if err := waitContainerStop(ctr, time.Duration(timeout)*time.Second); err != nil {
+			logrus.Warnf("Timed out stopping container %s, resorting to SIGKILL", ctr.ID())
+		} else {
+			// No error, the container is dead
+			return nil
+		}
+	}
+
+	if err := r.KillContainer(ctr, 9, all); err != nil {
+		// Again, check if the container is gone. If it is, exit cleanly.
+		err := unix.Kill(ctr.state.PID, 0)
+		if err == unix.ESRCH {
+			return nil
+		}
+
+		return errors.Wrapf(err, "error sending SIGKILL to container %s", ctr.ID())
+	}
+
+	// Give runtime a few seconds to make it happen
+	if err := waitContainerStop(ctr, killContainerTimeout); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// DeleteContainer deletes a container from the OCI runtime.
+func (r *ConmonOCIRuntime) DeleteContainer(ctr *Container) error {
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return err
+	}
+	env := []string{fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir)}
+	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, env, r.path, "delete", "--force", ctr.ID())
+}
+
+// PauseContainer pauses the given container.
+func (r *ConmonOCIRuntime) PauseContainer(ctr *Container) error {
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return err
+	}
+	env := []string{fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir)}
+	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, env, r.path, "pause", ctr.ID())
+}
+
+// UnpauseContainer unpauses the given container.
+func (r *ConmonOCIRuntime) UnpauseContainer(ctr *Container) error {
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return err
+	}
+	env := []string{fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir)}
+	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, env, r.path, "resume", ctr.ID())
+}
+
+// ExecContainer executes a command in a running container
+// TODO: Split into Create/Start/Attach/Wait
+func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options *ExecOptions) (int, chan error, error) {
+	if options == nil {
+		return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide an ExecOptions struct to ExecContainer")
+	}
+	if len(options.Cmd) == 0 {
+		return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide a command to execute")
+	}
+
+	if sessionID == "" {
+		return -1, nil, errors.Wrapf(define.ErrEmptyID, "must provide a session ID for exec")
+	}
+
+	// create sync pipe to receive the pid
+	parentSyncPipe, childSyncPipe, err := newPipe()
+	if err != nil {
+		return -1, nil, errors.Wrapf(err, "error creating socket pair")
+	}
+
+	defer errorhandling.CloseQuiet(parentSyncPipe)
+
+	// create start pipe to set the cgroup before running
+	// attachToExec is responsible for closing parentStartPipe
+	childStartPipe, parentStartPipe, err := newPipe()
+	if err != nil {
+		return -1, nil, errors.Wrapf(err, "error creating socket pair")
+	}
+
+	// We want to make sure we close the parent{Start,Attach}Pipes if we fail
+	// but also don't want to close them after attach to exec is called
+	attachToExecCalled := false
+
+	defer func() {
+		if !attachToExecCalled {
+			errorhandling.CloseQuiet(parentStartPipe)
+		}
+	}()
+
+	// create the attach pipe to allow attach socket to be created before
+	// $RUNTIME exec starts running. This is to make sure we can capture all output
+	// from the process through that socket, rather than half reading the log, half attaching to the socket
+	// attachToExec is responsible for closing parentAttachPipe
+	parentAttachPipe, childAttachPipe, err := newPipe()
+	if err != nil {
+		return -1, nil, errors.Wrapf(err, "error creating socket pair")
+	}
+
+	defer func() {
+		if !attachToExecCalled {
+			errorhandling.CloseQuiet(parentAttachPipe)
+		}
+	}()
+
+	childrenClosed := false
+	defer func() {
+		if !childrenClosed {
+			errorhandling.CloseQuiet(childSyncPipe)
+			errorhandling.CloseQuiet(childAttachPipe)
+			errorhandling.CloseQuiet(childStartPipe)
+		}
+	}()
+
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return -1, nil, err
+	}
+
+	finalEnv := make([]string, 0, len(options.Env))
+	for k, v := range options.Env {
+		finalEnv = append(finalEnv, fmt.Sprintf("%s=%s", k, v))
+	}
+
+	processFile, err := prepareProcessExec(c, options.Cmd, finalEnv, options.Terminal, options.Cwd, options.User, sessionID)
+	if err != nil {
+		return -1, nil, err
+	}
+
+	var ociLog string
+	if logrus.GetLevel() != logrus.DebugLevel && r.supportsJSON {
+		ociLog = c.execOCILog(sessionID)
+	}
+	args := r.sharedConmonArgs(c, sessionID, c.execBundlePath(sessionID), c.execPidPath(sessionID), c.execLogPath(sessionID), c.execExitFileDir(sessionID), ociLog)
+
+	if options.PreserveFDs > 0 {
+		args = append(args, formatRuntimeOpts("--preserve-fds", fmt.Sprintf("%d", options.PreserveFDs))...)
+	}
+
+	for _, capability := range options.CapAdd {
+		args = append(args, formatRuntimeOpts("--cap", capability)...)
+	}
+
+	if options.Terminal {
+		args = append(args, "-t")
+	}
+
+	// Append container ID and command
+	args = append(args, "-e")
+	// TODO make this optional when we can detach
+	args = append(args, "--exec-attach")
+	args = append(args, "--exec-process-spec", processFile.Name())
+
+	logrus.WithFields(logrus.Fields{
+		"args": args,
+	}).Debugf("running conmon: %s", r.conmonPath)
+	execCmd := exec.Command(r.conmonPath, args...)
+
+	if options.Streams != nil {
+		if options.Streams.AttachInput {
+			execCmd.Stdin = options.Streams.InputStream
+		}
+		if options.Streams.AttachOutput {
+			execCmd.Stdout = options.Streams.OutputStream
+		}
+		if options.Streams.AttachError {
+			execCmd.Stderr = options.Streams.ErrorStream
+		}
+	}
+
+	conmonEnv, extraFiles, err := r.configureConmonEnv(runtimeDir)
+	if err != nil {
+		return -1, nil, err
+	}
+
+	if options.PreserveFDs > 0 {
+		for fd := 3; fd < int(3+options.PreserveFDs); fd++ {
+			execCmd.ExtraFiles = append(execCmd.ExtraFiles, os.NewFile(uintptr(fd), fmt.Sprintf("fd-%d", fd)))
+		}
+	}
+
+	// we don't want to step on users fds they asked to preserve
+	// Since 0-2 are used for stdio, start the fds we pass in at preserveFDs+3
+	execCmd.Env = append(r.conmonEnv, fmt.Sprintf("_OCI_SYNCPIPE=%d", options.PreserveFDs+3), fmt.Sprintf("_OCI_STARTPIPE=%d", options.PreserveFDs+4), fmt.Sprintf("_OCI_ATTACHPIPE=%d", options.PreserveFDs+5))
+	execCmd.Env = append(execCmd.Env, conmonEnv...)
+
+	execCmd.ExtraFiles = append(execCmd.ExtraFiles, childSyncPipe, childStartPipe, childAttachPipe)
+	execCmd.ExtraFiles = append(execCmd.ExtraFiles, extraFiles...)
+	execCmd.Dir = c.execBundlePath(sessionID)
+	execCmd.SysProcAttr = &syscall.SysProcAttr{
+		Setpgid: true,
+	}
+
+	err = startCommandGivenSelinux(execCmd)
+
+	// We don't need children pipes  on the parent side
+	errorhandling.CloseQuiet(childSyncPipe)
+	errorhandling.CloseQuiet(childAttachPipe)
+	errorhandling.CloseQuiet(childStartPipe)
+	childrenClosed = true
+
+	if err != nil {
+		return -1, nil, errors.Wrapf(err, "cannot start container %s", c.ID())
+	}
+	if err := r.moveConmonToCgroupAndSignal(c, execCmd, parentStartPipe, sessionID); err != nil {
+		return -1, nil, err
+	}
+
+	if options.PreserveFDs > 0 {
+		for fd := 3; fd < int(3+options.PreserveFDs); fd++ {
+			// These fds were passed down to the runtime.  Close them
+			// and not interfere
+			if err := os.NewFile(uintptr(fd), fmt.Sprintf("fd-%d", fd)).Close(); err != nil {
+				logrus.Debugf("unable to close file fd-%d", fd)
+			}
+		}
+	}
+
+	// TODO Only create if !detach
+	// Attach to the container before starting it
+	attachChan := make(chan error)
+	go func() {
+		// attachToExec is responsible for closing pipes
+		attachChan <- c.attachToExec(options.Streams, options.DetachKeys, options.Resize, sessionID, parentStartPipe, parentAttachPipe)
+		close(attachChan)
+	}()
+	attachToExecCalled = true
+
+	pid, err := readConmonPipeData(parentSyncPipe, ociLog)
+
+	return pid, attachChan, err
+}
+
+// ExecStopContainer stops a given exec session in a running container.
+func (r *ConmonOCIRuntime) ExecStopContainer(ctr *Container, sessionID string, timeout uint) error {
+	session, ok := ctr.state.ExecSessions[sessionID]
+	if !ok {
+		// TODO This should probably be a separate error
+		return errors.Wrapf(define.ErrInvalidArg, "no exec session with ID %s found in container %s", sessionID, ctr.ID())
+	}
+
+	logrus.Debugf("Going to stop container %s exec session %s", ctr.ID(), sessionID)
+
+	// Is the session dead?
+	// Ping the PID with signal 0 to see if it still exists.
+	if err := unix.Kill(session.PID, 0); err != nil {
+		if err == unix.ESRCH {
+			return nil
+		}
+		return errors.Wrapf(err, "error pinging container %s exec session %s PID %d with signal 0", ctr.ID(), sessionID, session.PID)
+	}
+
+	if timeout > 0 {
+		// Use SIGTERM by default, then SIGSTOP after timeout.
+		logrus.Debugf("Killing exec session %s (PID %d) of container %s with SIGTERM", sessionID, session.PID, ctr.ID())
+		if err := unix.Kill(session.PID, unix.SIGTERM); err != nil {
+			if err == unix.ESRCH {
+				return nil
+			}
+			return errors.Wrapf(err, "error killing container %s exec session %s PID %d with SIGTERM", ctr.ID(), sessionID, session.PID)
+		}
+
+		// Wait for the PID to stop
+		if err := waitPidStop(session.PID, time.Duration(timeout)*time.Second); err != nil {
+			logrus.Warnf("Timed out waiting for container %s exec session %s to stop, resorting to SIGKILL", ctr.ID(), sessionID)
+		} else {
+			// No error, container is dead
+			return nil
+		}
+	}
+
+	// SIGTERM did not work. On to SIGKILL.
+	logrus.Debugf("Killing exec session %s (PID %d) of container %s with SIGKILL", sessionID, session.PID, ctr.ID())
+	if err := unix.Kill(session.PID, unix.SIGTERM); err != nil {
+		if err == unix.ESRCH {
+			return nil
+		}
+		return errors.Wrapf(err, "error killing container %s exec session %s PID %d with SIGKILL", ctr.ID(), sessionID, session.PID)
+	}
+
+	// Wait for the PID to stop
+	if err := waitPidStop(session.PID, killContainerTimeout*time.Second); err != nil {
+		return errors.Wrapf(err, "timed out waiting for container %s exec session %s PID %d to stop after SIGKILL", ctr.ID(), sessionID, session.PID)
+	}
+
+	return nil
+}
+
+// ExecCleanupContainer cleans up files created when a command is run via
+// ExecContainer. This includes the attach socket for the exec session.
+func (r *ConmonOCIRuntime) ExecContainerCleanup(ctr *Container, sessionID string) error {
+	// Clean up the sockets dir. Issue #3962
+	// Also ignore if it doesn't exist for some reason; hence the conditional return below
+	if err := os.RemoveAll(filepath.Join(r.socketsDir, sessionID)); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
+}
+
+// CheckpointContainer checkpoints the given container.
+func (r *ConmonOCIRuntime) CheckpointContainer(ctr *Container, options ContainerCheckpointOptions) error {
+	if err := label.SetSocketLabel(ctr.ProcessLabel()); err != nil {
+		return err
+	}
+	// imagePath is used by CRIU to store the actual checkpoint files
+	imagePath := ctr.CheckpointPath()
+	// workPath will be used to store dump.log and stats-dump
+	workPath := ctr.bundlePath()
+	logrus.Debugf("Writing checkpoint to %s", imagePath)
+	logrus.Debugf("Writing checkpoint logs to %s", workPath)
+	args := []string{}
+	args = append(args, "checkpoint")
+	args = append(args, "--image-path")
+	args = append(args, imagePath)
+	args = append(args, "--work-path")
+	args = append(args, workPath)
+	if options.KeepRunning {
+		args = append(args, "--leave-running")
+	}
+	if options.TCPEstablished {
+		args = append(args, "--tcp-established")
+	}
+	args = append(args, ctr.ID())
+	return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, nil, r.path, args...)
+}
+
+// SupportsCheckpoint checks if the OCI runtime supports checkpointing
+// containers.
+func (r *ConmonOCIRuntime) SupportsCheckpoint() bool {
+	// Check if the runtime implements checkpointing. Currently only
+	// runc's checkpoint/restore implementation is supported.
+	cmd := exec.Command(r.path, "checkpoint", "-h")
+	if err := cmd.Start(); err != nil {
+		return false
+	}
+	if err := cmd.Wait(); err == nil {
+		return true
+	}
+	return false
+}
+
+// SupportsJSONErrors checks if the OCI runtime supports JSON-formatted error
+// messages.
+func (r *ConmonOCIRuntime) SupportsJSONErrors() bool {
+	return r.supportsJSON
+}
+
+// SupportsNoCgroups checks if the OCI runtime supports running containers
+// without cgroups (the --cgroup-manager=disabled flag).
+func (r *ConmonOCIRuntime) SupportsNoCgroups() bool {
+	return r.supportsNoCgroups
+}
+
+// AttachSocketPath is the path to a single container's attach socket.
+func (r *ConmonOCIRuntime) AttachSocketPath(ctr *Container) (string, error) {
+	if ctr == nil {
+		return "", errors.Wrapf(define.ErrInvalidArg, "must provide a valid container to get attach socket path")
+	}
+
+	return filepath.Join(r.socketsDir, ctr.ID(), "attach"), nil
+}
+
+// ExecAttachSocketPath is the path to a container's exec session attach socket.
+func (r *ConmonOCIRuntime) ExecAttachSocketPath(ctr *Container, sessionID string) (string, error) {
+	// We don't even use container, so don't validity check it
+	if sessionID == "" {
+		return "", errors.Wrapf(define.ErrInvalidArg, "must provide a valid session ID to get attach socket path")
+	}
+
+	return filepath.Join(r.socketsDir, sessionID, "attach"), nil
+}
+
+// ExitFilePath is the path to a container's exit file.
+func (r *ConmonOCIRuntime) ExitFilePath(ctr *Container) (string, error) {
+	if ctr == nil {
+		return "", errors.Wrapf(define.ErrInvalidArg, "must provide a valid container to get exit file path")
+	}
+	return filepath.Join(r.exitsDir, ctr.ID()), nil
+}
+
+// RuntimeInfo provides information on the runtime.
+func (r *ConmonOCIRuntime) RuntimeInfo() (map[string]interface{}, error) {
+	runtimePackage := packageVersion(r.path)
+	conmonPackage := packageVersion(r.conmonPath)
+	runtimeVersion, err := r.getOCIRuntimeVersion()
+	if err != nil {
+		return nil, errors.Wrapf(err, "error getting version of OCI runtime %s", r.name)
+	}
+	conmonVersion, err := r.getConmonVersion()
+	if err != nil {
+		return nil, errors.Wrapf(err, "error getting conmon version")
+	}
+
+	info := make(map[string]interface{})
+	info["Conmon"] = map[string]interface{}{
+		"path":    r.conmonPath,
+		"package": conmonPackage,
+		"version": conmonVersion,
+	}
+	info["OCIRuntime"] = map[string]interface{}{
+		"path":    r.path,
+		"package": runtimePackage,
+		"version": runtimeVersion,
+	}
+
+	return info, nil
+}
+
+// makeAccessible changes the path permission and each parent directory to have --x--x--x
+func makeAccessible(path string, uid, gid int) error {
+	for ; path != "/"; path = filepath.Dir(path) {
+		st, err := os.Stat(path)
+		if err != nil {
+			if os.IsNotExist(err) {
+				return nil
+			}
+			return err
+		}
+		if int(st.Sys().(*syscall.Stat_t).Uid) == uid && int(st.Sys().(*syscall.Stat_t).Gid) == gid {
+			continue
+		}
+		if st.Mode()&0111 != 0111 {
+			if err := os.Chmod(path, st.Mode()|0111); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// Wait for a container which has been sent a signal to stop
+func waitContainerStop(ctr *Container, timeout time.Duration) error {
+	return waitPidStop(ctr.state.PID, timeout)
+}
+
+// Wait for a given PID to stop
+func waitPidStop(pid int, timeout time.Duration) error {
+	done := make(chan struct{})
+	chControl := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case <-chControl:
+				return
+			default:
+				if err := unix.Kill(pid, 0); err != nil {
+					if err == unix.ESRCH {
+						close(done)
+						return
+					}
+					logrus.Errorf("Error pinging PID %d with signal 0: %v", pid, err)
+				}
+				time.Sleep(100 * time.Millisecond)
+			}
+		}
+	}()
+	select {
+	case <-done:
+		return nil
+	case <-time.After(timeout):
+		close(chControl)
+		return errors.Errorf("given PIDs did not die within timeout")
+	}
+}
+
+// createOCIContainer generates this container's main conmon instance and prepares it for starting
+func (r *ConmonOCIRuntime) createOCIContainer(ctr *Container, restoreOptions *ContainerCheckpointOptions) (err error) {
+	var stderrBuf bytes.Buffer
+
+	runtimeDir, err := util.GetRuntimeDir()
+	if err != nil {
+		return err
+	}
+
+	parentSyncPipe, childSyncPipe, err := newPipe()
+	if err != nil {
+		return errors.Wrapf(err, "error creating socket pair")
+	}
+	defer errorhandling.CloseQuiet(parentSyncPipe)
+
+	childStartPipe, parentStartPipe, err := newPipe()
+	if err != nil {
+		return errors.Wrapf(err, "error creating socket pair for start pipe")
+	}
+
+	defer errorhandling.CloseQuiet(parentStartPipe)
+
+	var ociLog string
+	if logrus.GetLevel() != logrus.DebugLevel && r.supportsJSON {
+		ociLog = filepath.Join(ctr.state.RunDir, "oci-log")
+	}
+	args := r.sharedConmonArgs(ctr, ctr.ID(), ctr.bundlePath(), filepath.Join(ctr.state.RunDir, "pidfile"), ctr.LogPath(), r.exitsDir, ociLog)
+
+	if ctr.config.Spec.Process.Terminal {
+		args = append(args, "-t")
+	} else if ctr.config.Stdin {
+		args = append(args, "-i")
+	}
+
+	if ctr.config.ConmonPidFile != "" {
+		args = append(args, "--conmon-pidfile", ctr.config.ConmonPidFile)
+	}
+
+	if r.noPivot {
+		args = append(args, "--no-pivot")
+	}
+
+	if len(ctr.config.ExitCommand) > 0 {
+		args = append(args, "--exit-command", ctr.config.ExitCommand[0])
+		for _, arg := range ctr.config.ExitCommand[1:] {
+			args = append(args, []string{"--exit-command-arg", arg}...)
+		}
+	}
+
+	if restoreOptions != nil {
+		args = append(args, "--restore", ctr.CheckpointPath())
+		if restoreOptions.TCPEstablished {
+			args = append(args, "--runtime-opt", "--tcp-established")
+		}
+	}
+
+	logrus.WithFields(logrus.Fields{
+		"args": args,
+	}).Debugf("running conmon: %s", r.conmonPath)
+
+	cmd := exec.Command(r.conmonPath, args...)
+	cmd.Dir = ctr.bundlePath()
+	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
+	}
+
+	// 0, 1 and 2 are stdin, stdout and stderr
+	conmonEnv, envFiles, err := r.configureConmonEnv(runtimeDir)
+	if err != nil {
+		return err
+	}
+
+	cmd.Env = append(r.conmonEnv, fmt.Sprintf("_OCI_SYNCPIPE=%d", 3), fmt.Sprintf("_OCI_STARTPIPE=%d", 4))
+	cmd.Env = append(cmd.Env, conmonEnv...)
+	cmd.ExtraFiles = append(cmd.ExtraFiles, childSyncPipe, childStartPipe)
+	cmd.ExtraFiles = append(cmd.ExtraFiles, envFiles...)
+
+	if r.reservePorts && !ctr.config.NetMode.IsSlirp4netns() {
+		ports, err := bindPorts(ctr.config.PortMappings)
+		if err != nil {
+			return err
+		}
+
+		// Leak the port we bound in the conmon process.  These fd's won't be used
+		// by the container and conmon will keep the ports busy so that another
+		// process cannot use them.
+		cmd.ExtraFiles = append(cmd.ExtraFiles, ports...)
+	}
+
+	if ctr.config.NetMode.IsSlirp4netns() {
+		if ctr.config.PostConfigureNetNS {
+			ctr.rootlessSlirpSyncR, ctr.rootlessSlirpSyncW, err = os.Pipe()
+			if err != nil {
+				return errors.Wrapf(err, "failed to create rootless network sync pipe")
+			}
+		} else {
+			if ctr.rootlessSlirpSyncR != nil {
+				defer errorhandling.CloseQuiet(ctr.rootlessSlirpSyncR)
+			}
+			if ctr.rootlessSlirpSyncW != nil {
+				defer errorhandling.CloseQuiet(ctr.rootlessSlirpSyncW)
+			}
+		}
+		// Leak one end in conmon, the other one will be leaked into slirp4netns
+		cmd.ExtraFiles = append(cmd.ExtraFiles, ctr.rootlessSlirpSyncW)
+	}
+
+	err = startCommandGivenSelinux(cmd)
+	// regardless of whether we errored or not, we no longer need the children pipes
+	childSyncPipe.Close()
+	childStartPipe.Close()
+	if err != nil {
+		return err
+	}
+	if err := r.moveConmonToCgroupAndSignal(ctr, cmd, parentStartPipe, ctr.ID()); err != nil {
+		return err
+	}
+	/* Wait for initial setup and fork, and reap child */
+	err = cmd.Wait()
+	if err != nil {
+		return err
+	}
+
+	pid, err := readConmonPipeData(parentSyncPipe, ociLog)
+	if err != nil {
+		if err2 := r.DeleteContainer(ctr); err2 != nil {
+			logrus.Errorf("Error removing container %s from runtime after creation failed", ctr.ID())
+		}
+		return err
+	}
+	ctr.state.PID = pid
+
+	conmonPID, err := readConmonPidFile(ctr.config.ConmonPidFile)
+	if err != nil {
+		logrus.Warnf("error reading conmon pid file for container %s: %s", ctr.ID(), err.Error())
+	} else if conmonPID > 0 {
+		// conmon not having a pid file is a valid state, so don't set it if we don't have it
+		logrus.Infof("Got Conmon PID as %d", conmonPID)
+		ctr.state.ConmonPID = conmonPID
+	}
+
+	return nil
+}
+
+// prepareProcessExec returns the path of the process.json used in runc exec -p
+// caller is responsible to close the returned *os.File if needed.
+func prepareProcessExec(c *Container, cmd, env []string, tty bool, cwd, user, sessionID string) (*os.File, error) {
+	f, err := ioutil.TempFile(c.execBundlePath(sessionID), "exec-process-")
+	if err != nil {
+		return nil, err
+	}
+
+	pspec := c.config.Spec.Process
+	pspec.Args = cmd
+	// We need to default this to false else it will inherit terminal as true
+	// from the container.
+	pspec.Terminal = false
+	if tty {
+		pspec.Terminal = true
+	}
+	if len(env) > 0 {
+		pspec.Env = append(pspec.Env, env...)
+	}
+
+	if cwd != "" {
+		pspec.Cwd = cwd
+
+	}
+
+	overrides := c.getUserOverrides()
+	execUser, err := lookup.GetUserGroupInfo(c.state.Mountpoint, user, overrides)
+	if err != nil {
+		return nil, err
+	}
+
+	// If user was set, look it up in the container to get a UID to use on
+	// the host
+	if user != "" {
+		sgids := make([]uint32, 0, len(execUser.Sgids))
+		for _, sgid := range execUser.Sgids {
+			sgids = append(sgids, uint32(sgid))
+		}
+		processUser := spec.User{
+			UID:            uint32(execUser.Uid),
+			GID:            uint32(execUser.Gid),
+			AdditionalGids: sgids,
+		}
+
+		pspec.User = processUser
+	}
+
+	hasHomeSet := false
+	for _, s := range pspec.Env {
+		if strings.HasPrefix(s, "HOME=") {
+			hasHomeSet = true
+			break
+		}
+	}
+	if !hasHomeSet {
+		pspec.Env = append(pspec.Env, fmt.Sprintf("HOME=%s", execUser.Home))
+	}
+
+	processJSON, err := json.Marshal(pspec)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := ioutil.WriteFile(f.Name(), processJSON, 0644); err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+// configureConmonEnv gets the environment values to add to conmon's exec struct
+// TODO this may want to be less hardcoded/more configurable in the future
+func (r *ConmonOCIRuntime) configureConmonEnv(runtimeDir string) ([]string, []*os.File, error) {
+	env := make([]string, 0, 6)
+	env = append(env, fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir))
+	env = append(env, fmt.Sprintf("_CONTAINERS_USERNS_CONFIGURED=%s", os.Getenv("_CONTAINERS_USERNS_CONFIGURED")))
+	env = append(env, fmt.Sprintf("_CONTAINERS_ROOTLESS_UID=%s", os.Getenv("_CONTAINERS_ROOTLESS_UID")))
+	home, err := homeDir()
+	if err != nil {
+		return nil, nil, err
+	}
+	env = append(env, fmt.Sprintf("HOME=%s", home))
+
+	extraFiles := make([]*os.File, 0)
+	if notify, ok := os.LookupEnv("NOTIFY_SOCKET"); ok {
+		env = append(env, fmt.Sprintf("NOTIFY_SOCKET=%s", notify))
+	}
+	if !r.sdNotify {
+		if listenfds, ok := os.LookupEnv("LISTEN_FDS"); ok {
+			env = append(env, fmt.Sprintf("LISTEN_FDS=%s", listenfds), "LISTEN_PID=1")
+			fds := activation.Files(false)
+			extraFiles = append(extraFiles, fds...)
+		}
+	} else {
+		logrus.Debug("disabling SD notify")
+	}
+	return env, extraFiles, nil
+}
+
+// sharedConmonArgs takes common arguments for exec and create/restore and formats them for the conmon CLI
+func (r *ConmonOCIRuntime) sharedConmonArgs(ctr *Container, cuuid, bundlePath, pidPath, logPath, exitDir, ociLogPath string) []string {
+	// set the conmon API version to be able to use the correct sync struct keys
+	args := []string{"--api-version", "1"}
+	if r.cgroupManager == SystemdCgroupsManager && !ctr.config.NoCgroups {
+		args = append(args, "-s")
+	}
+	args = append(args, "-c", ctr.ID())
+	args = append(args, "-u", cuuid)
+	args = append(args, "-r", r.path)
+	args = append(args, "-b", bundlePath)
+	args = append(args, "-p", pidPath)
+
+	var logDriver string
+	switch ctr.LogDriver() {
+	case JournaldLogging:
+		logDriver = JournaldLogging
+	case JSONLogging:
+		fallthrough
+	default: //nolint-stylecheck
+		// No case here should happen except JSONLogging, but keep this here in case the options are extended
+		logrus.Errorf("%s logging specified but not supported. Choosing k8s-file logging instead", ctr.LogDriver())
+		fallthrough
+	case "":
+		// to get here, either a user would specify `--log-driver ""`, or this came from another place in libpod
+		// since the former case is obscure, and the latter case isn't an error, let's silently fallthrough
+		fallthrough
+	case KubernetesLogging:
+		logDriver = fmt.Sprintf("%s:%s", KubernetesLogging, logPath)
+	}
+
+	args = append(args, "-l", logDriver)
+	args = append(args, "--exit-dir", exitDir)
+	args = append(args, "--socket-dir-path", r.socketsDir)
+	if r.logSizeMax >= 0 {
+		args = append(args, "--log-size-max", fmt.Sprintf("%v", r.logSizeMax))
+	}
+
+	logLevel := logrus.GetLevel()
+	args = append(args, "--log-level", logLevel.String())
+
+	if logLevel == logrus.DebugLevel {
+		logrus.Debugf("%s messages will be logged to syslog", r.conmonPath)
+		args = append(args, "--syslog")
+	}
+	if ociLogPath != "" {
+		args = append(args, "--runtime-arg", "--log-format=json", "--runtime-arg", "--log", fmt.Sprintf("--runtime-arg=%s", ociLogPath))
+	}
+	if ctr.config.NoCgroups {
+		logrus.Debugf("Running with no CGroups")
+		args = append(args, "--runtime-arg", "--cgroup-manager", "--runtime-arg", "disabled")
+	}
+	return args
+}
+
+// startCommandGivenSelinux starts a container ensuring to set the labels of
+// the process to make sure SELinux doesn't block conmon communication, if SELinux is enabled
+func startCommandGivenSelinux(cmd *exec.Cmd) error {
+	if !selinux.GetEnabled() {
+		return cmd.Start()
+	}
+	// Set the label of the conmon process to be level :s0
+	// This will allow the container processes to talk to fifo-files
+	// passed into the container by conmon
+	var (
+		plabel string
+		con    selinux.Context
+		err    error
+	)
+	plabel, err = selinux.CurrentLabel()
+	if err != nil {
+		return errors.Wrapf(err, "Failed to get current SELinux label")
+	}
+
+	con, err = selinux.NewContext(plabel)
+	if err != nil {
+		return errors.Wrapf(err, "Failed to get new context from SELinux label")
+	}
+
+	runtime.LockOSThread()
+	if con["level"] != "s0" && con["level"] != "" {
+		con["level"] = "s0"
+		if err = label.SetProcessLabel(con.Get()); err != nil {
+			runtime.UnlockOSThread()
+			return err
+		}
+	}
+	err = cmd.Start()
+	// Ignore error returned from SetProcessLabel("") call,
+	// can't recover.
+	if labelErr := label.SetProcessLabel(""); labelErr != nil {
+		logrus.Errorf("unable to set process label: %q", err)
+	}
+	runtime.UnlockOSThread()
+	return err
+}
+
+// moveConmonToCgroupAndSignal gets a container's cgroupParent and moves the conmon process to that cgroup
+// it then signals for conmon to start by sending nonse data down the start fd
+func (r *ConmonOCIRuntime) moveConmonToCgroupAndSignal(ctr *Container, cmd *exec.Cmd, startFd *os.File, uuid string) error {
+	mustCreateCgroup := true
+	// If cgroup creation is disabled - just signal.
+	if ctr.config.NoCgroups {
+		mustCreateCgroup = false
+	}
+
+	if rootless.IsRootless() {
+		ownsCgroup, err := cgroups.UserOwnsCurrentSystemdCgroup()
+		if err != nil {
+			return err
+		}
+		mustCreateCgroup = !ownsCgroup
+	}
+
+	if mustCreateCgroup {
+		cgroupParent := ctr.CgroupParent()
+		if r.cgroupManager == SystemdCgroupsManager {
+			unitName := createUnitName("libpod-conmon", ctr.ID())
+
+			realCgroupParent := cgroupParent
+			splitParent := strings.Split(cgroupParent, "/")
+			if strings.HasSuffix(cgroupParent, ".slice") && len(splitParent) > 1 {
+				realCgroupParent = splitParent[len(splitParent)-1]
+			}
+
+			logrus.Infof("Running conmon under slice %s and unitName %s", realCgroupParent, unitName)
+			if err := utils.RunUnderSystemdScope(cmd.Process.Pid, realCgroupParent, unitName); err != nil {
+				logrus.Warnf("Failed to add conmon to systemd sandbox cgroup: %v", err)
+			}
+		} else {
+			cgroupPath := filepath.Join(ctr.config.CgroupParent, "conmon")
+			control, err := cgroups.New(cgroupPath, &spec.LinuxResources{})
+			if err != nil {
+				logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err)
+			} else {
+				// we need to remove this defer and delete the cgroup once conmon exits
+				// maybe need a conmon monitor?
+				if err := control.AddPid(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 */
+	if err := writeConmonPipeData(startFd); err != nil {
+		return err
+	}
+	return 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_SEQPACKET|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
+}
+
+// readConmonPidFile attempts to read conmon's pid from its pid file
+func readConmonPidFile(pidFile string) (int, error) {
+	// Let's try reading the Conmon pid at the same time.
+	if pidFile != "" {
+		contents, err := ioutil.ReadFile(pidFile)
+		if err != nil {
+			return -1, err
+		}
+		// Convert it to an int
+		conmonPID, err := strconv.Atoi(string(contents))
+		if err != nil {
+			return -1, err
+		}
+		return conmonPID, nil
+	}
+	return 0, nil
+}
+
+// readConmonPipeData attempts to read a syncInfo struct from the pipe
+func readConmonPipeData(pipe *os.File, ociLog string) (int, error) {
+	// syncInfo is used to return data from monitor process to daemon
+	type syncInfo struct {
+		Data    int    `json:"data"`
+		Message string `json:"message,omitempty"`
+	}
+
+	// Wait to get container pid from conmon
+	type syncStruct struct {
+		si  *syncInfo
+		err error
+	}
+	ch := make(chan syncStruct)
+	go func() {
+		var si *syncInfo
+		rdr := bufio.NewReader(pipe)
+		b, err := rdr.ReadBytes('\n')
+		if err != nil {
+			ch <- syncStruct{err: err}
+		}
+		if err := json.Unmarshal(b, &si); err != nil {
+			ch <- syncStruct{err: err}
+			return
+		}
+		ch <- syncStruct{si: si}
+	}()
+
+	data := -1
+	select {
+	case ss := <-ch:
+		if ss.err != nil {
+			if ociLog != "" {
+				ociLogData, err := ioutil.ReadFile(ociLog)
+				if err == nil {
+					var ociErr ociError
+					if err := json.Unmarshal(ociLogData, &ociErr); err == nil {
+						return -1, getOCIRuntimeError(ociErr.Msg)
+					}
+				}
+			}
+			return -1, errors.Wrapf(ss.err, "error reading container (probably exited) json message")
+		}
+		logrus.Debugf("Received: %d", ss.si.Data)
+		if ss.si.Data < 0 {
+			if ociLog != "" {
+				ociLogData, err := ioutil.ReadFile(ociLog)
+				if err == nil {
+					var ociErr ociError
+					if err := json.Unmarshal(ociLogData, &ociErr); err == nil {
+						return ss.si.Data, getOCIRuntimeError(ociErr.Msg)
+					}
+				}
+			}
+			// If we failed to parse the JSON errors, then print the output as it is
+			if ss.si.Message != "" {
+				return ss.si.Data, getOCIRuntimeError(ss.si.Message)
+			}
+			return ss.si.Data, errors.Wrapf(define.ErrInternal, "container create failed")
+		}
+		data = ss.si.Data
+	case <-time.After(ContainerCreateTimeout):
+		return -1, errors.Wrapf(define.ErrInternal, "container creation timeout")
+	}
+	return data, nil
+}
+
+// writeConmonPipeData writes nonse data to a pipe
+func writeConmonPipeData(pipe *os.File) error {
+	someData := []byte{0}
+	_, err := pipe.Write(someData)
+	return err
+}
+
+// formatRuntimeOpts prepends opts passed to it with --runtime-opt for passing to conmon
+func formatRuntimeOpts(opts ...string) []string {
+	args := make([]string, 0, len(opts)*2)
+	for _, o := range opts {
+		args = append(args, "--runtime-opt", o)
+	}
+	return args
+}
+
+// getConmonVersion returns a string representation of the conmon version.
+func (r *ConmonOCIRuntime) getConmonVersion() (string, error) {
+	output, err := utils.ExecCmd(r.conmonPath, "--version")
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSuffix(strings.Replace(output, "\n", ", ", 1), "\n"), nil
+}
+
+// getOCIRuntimeVersion returns a string representation of the OCI runtime's
+// version.
+func (r *ConmonOCIRuntime) getOCIRuntimeVersion() (string, error) {
+	output, err := utils.ExecCmd(r.path, "--version")
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSuffix(output, "\n"), nil
+}