//go:build windows

package main

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"time"

	eventstypes "github.com/containerd/containerd/api/events"
	"github.com/containerd/containerd/errdefs"
	"github.com/containerd/containerd/runtime"
	"github.com/containerd/containerd/runtime/v2/task"
	"github.com/containerd/typeurl"
	"github.com/opencontainers/runtime-spec/specs-go"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"go.opencensus.io/trace"

	"github.com/Microsoft/go-winio/pkg/fs"
	runhcsopts "github.com/Microsoft/hcsshim/cmd/containerd-shim-runhcs-v1/options"
	"github.com/Microsoft/hcsshim/cmd/containerd-shim-runhcs-v1/stats"
	"github.com/Microsoft/hcsshim/internal/cmd"
	"github.com/Microsoft/hcsshim/internal/cow"
	"github.com/Microsoft/hcsshim/internal/guestpath"
	"github.com/Microsoft/hcsshim/internal/hcs"
	"github.com/Microsoft/hcsshim/internal/hcs/resourcepaths"
	"github.com/Microsoft/hcsshim/internal/hcs/schema1"
	hcsschema "github.com/Microsoft/hcsshim/internal/hcs/schema2"
	"github.com/Microsoft/hcsshim/internal/hcsoci"
	"github.com/Microsoft/hcsshim/internal/jobcontainers"
	"github.com/Microsoft/hcsshim/internal/log"
	"github.com/Microsoft/hcsshim/internal/memory"
	"github.com/Microsoft/hcsshim/internal/oc"
	"github.com/Microsoft/hcsshim/internal/oci"
	"github.com/Microsoft/hcsshim/internal/processorinfo"
	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
	"github.com/Microsoft/hcsshim/internal/protocol/guestresource"
	"github.com/Microsoft/hcsshim/internal/resources"
	"github.com/Microsoft/hcsshim/internal/shimdiag"
	"github.com/Microsoft/hcsshim/internal/uvm"
	"github.com/Microsoft/hcsshim/osversion"
	"github.com/Microsoft/hcsshim/pkg/annotations"
	"github.com/Microsoft/hcsshim/pkg/ctrdtaskapi"
)

func newHcsStandaloneTask(ctx context.Context, events publisher, req *task.CreateTaskRequest, s *specs.Spec) (shimTask, error) {
	log.G(ctx).WithField("tid", req.ID).Debug("newHcsStandaloneTask")

	ct, _, err := oci.GetSandboxTypeAndID(s.Annotations)
	if err != nil {
		return nil, err
	}
	if ct != oci.KubernetesContainerTypeNone {
		return nil, errors.Wrapf(
			errdefs.ErrFailedPrecondition,
			"cannot create standalone task, expected no annotation: '%s': got '%s'",
			annotations.KubernetesContainerType,
			ct)
	}

	owner := filepath.Base(os.Args[0])

	var parent *uvm.UtilityVM
	if osversion.Build() >= osversion.RS5 && oci.IsIsolated(s) {
		// Create the UVM parent
		opts, err := oci.SpecToUVMCreateOpts(ctx, s, fmt.Sprintf("%s@vm", req.ID), owner)
		if err != nil {
			return nil, err
		}
		switch opts.(type) {
		case *uvm.OptionsLCOW:
			lopts := (opts).(*uvm.OptionsLCOW)
			parent, err = uvm.CreateLCOW(ctx, lopts)
			if err != nil {
				return nil, err
			}
		case *uvm.OptionsWCOW:
			wopts := (opts).(*uvm.OptionsWCOW)

			// In order for the UVM sandbox.vhdx not to collide with the actual
			// nested Argon sandbox.vhdx we append the \vm folder to the last
			// entry in the list.
			layersLen := len(s.Windows.LayerFolders)
			layers := make([]string, layersLen)
			copy(layers, s.Windows.LayerFolders)

			vmPath := filepath.Join(layers[layersLen-1], "vm")
			err := os.MkdirAll(vmPath, 0)
			if err != nil {
				return nil, err
			}
			layers[layersLen-1] = vmPath
			wopts.LayerFolders = layers

			parent, err = uvm.CreateWCOW(ctx, wopts)
			if err != nil {
				return nil, err
			}
		}
		err = parent.Start(ctx)
		if err != nil {
			parent.Close()
		}
	} else if !oci.IsWCOW(s) {
		return nil, errors.Wrap(errdefs.ErrFailedPrecondition, "oci spec does not contain WCOW or LCOW spec")
	}

	shim, err := newHcsTask(ctx, events, parent, true, req, s)
	if err != nil {
		if parent != nil {
			parent.Close()
		}
		return nil, err
	}
	return shim, nil
}

// createContainer is a generic call to return either a process/hypervisor isolated container, or a job container
// based on what is set in the OCI spec.
func createContainer(ctx context.Context, id, owner, netNS string, s *specs.Spec, parent *uvm.UtilityVM, shimOpts *runhcsopts.Options) (cow.Container, *resources.Resources, error) {
	var (
		err       error
		container cow.Container
		resources *resources.Resources
	)

	if oci.IsJobContainer(s) {
		container, resources, err = jobcontainers.Create(ctx, id, s)
		if err != nil {
			return nil, nil, err
		}
	} else {
		opts := &hcsoci.CreateOptions{
			ID:               id,
			Owner:            owner,
			Spec:             s,
			HostingSystem:    parent,
			NetworkNamespace: netNS,
		}
		if shimOpts != nil {
			opts.ScaleCPULimitsToSandbox = shimOpts.ScaleCpuLimitsToSandbox
		}
		container, resources, err = hcsoci.CreateContainer(ctx, opts)
		if err != nil {
			return nil, nil, err
		}
	}
	return container, resources, nil
}

// newHcsTask creates a container within `parent` and its init exec process in
// the `shimExecCreated` state and returns the task that tracks its lifetime.
//
// If `parent == nil` the container is created on the host.
func newHcsTask(
	ctx context.Context,
	events publisher,
	parent *uvm.UtilityVM,
	ownsParent bool,
	req *task.CreateTaskRequest,
	s *specs.Spec) (_ shimTask, err error) {
	log.G(ctx).WithFields(logrus.Fields{
		"tid":        req.ID,
		"ownsParent": ownsParent,
	}).Debug("newHcsTask")

	owner := filepath.Base(os.Args[0])

	var netNS string
	if s.Windows != nil &&
		s.Windows.Network != nil {
		netNS = s.Windows.Network.NetworkNamespace
	}

	var shimOpts *runhcsopts.Options
	if req.Options != nil {
		v, err := typeurl.UnmarshalAny(req.Options)
		if err != nil {
			return nil, err
		}
		shimOpts = v.(*runhcsopts.Options)
	}

	// Default to an infinite timeout (zero value)
	var ioRetryTimeout time.Duration
	if shimOpts != nil {
		ioRetryTimeout = time.Duration(shimOpts.IoRetryTimeoutInSec) * time.Second
	}
	io, err := cmd.NewUpstreamIO(ctx, req.ID, req.Stdout, req.Stderr, req.Stdin, req.Terminal, ioRetryTimeout)
	if err != nil {
		return nil, err
	}

	container, resources, err := createContainer(ctx, req.ID, owner, netNS, s, parent, shimOpts)
	if err != nil {
		return nil, err
	}

	ht := &hcsTask{
		events:         events,
		id:             req.ID,
		isWCOW:         oci.IsWCOW(s),
		c:              container,
		cr:             resources,
		ownsHost:       ownsParent,
		host:           parent,
		closed:         make(chan struct{}),
		taskSpec:       s,
		ioRetryTimeout: ioRetryTimeout,
	}
	ht.init = newHcsExec(
		ctx,
		events,
		req.ID,
		parent,
		container,
		req.ID,
		req.Bundle,
		ht.isWCOW,
		s.Process,
		io,
	)

	if parent != nil {
		// We have a parent UVM. Listen for its exit and forcibly close this
		// task. This is not expected but in the event of a UVM crash we need to
		// handle this case.
		go ht.waitForHostExit()
	}

	go ht.waitInitExit()

	// Publish the created event
	if err := ht.events.publishEvent(
		ctx,
		runtime.TaskCreateEventTopic,
		&eventstypes.TaskCreate{
			ContainerID: req.ID,
			Bundle:      req.Bundle,
			Rootfs:      req.Rootfs,
			IO: &eventstypes.TaskIO{
				Stdin:    req.Stdin,
				Stdout:   req.Stdout,
				Stderr:   req.Stderr,
				Terminal: req.Terminal,
			},
			Checkpoint: "",
			Pid:        uint32(ht.init.Pid()),
		}); err != nil {
		return nil, err
	}
	return ht, nil
}

var _ = (shimTask)(&hcsTask{})

// hcsTask is a generic task that represents a WCOW Container (process or
// hypervisor isolated), or a LCOW Container. This task MAY own the UVM the
// container is in but in the case of a POD it may just track the UVM for
// container lifetime management. In the case of ownership when the init
// task/exec is stopped the UVM itself will be stopped as well.
type hcsTask struct {
	events publisher
	// id is the id of this task when it is created.
	//
	// It MUST be treated as read only in the liftetime of the task.
	id string
	// isWCOW is set to `true` if this is a task representing a Windows container.
	//
	// It MUST be treated as read only in the liftetime of the task.
	isWCOW bool
	// c is the container backing this task.
	//
	// It MUST be treated as read only in the lifetime of this task EXCEPT after
	// a Kill to the init task in which it must be shutdown.
	c cow.Container
	// cr is the container resources this task is holding.
	//
	// It MUST be treated as read only in the lifetime of this task EXCEPT after
	// a Kill to the init task in which all resources must be released.
	cr *resources.Resources
	// init is the init process of the container.
	//
	// Note: the invariant `container state == init.State()` MUST be true. IE:
	// if the init process exits the container as a whole and all exec's MUST
	// exit.
	//
	// It MUST be treated as read only in the lifetime of the task.
	init shimExec
	// ownsHost is `true` if this task owns `host`. If so when this tasks init
	// exec shuts down it is required that `host` be shut down as well.
	ownsHost bool
	// host is the hosting VM for this exec if hypervisor isolated. If
	// `host==nil` this is an Argon task so no UVM cleanup is required.
	//
	// NOTE: if `osversion.Build() < osversion.RS5` this will always be
	// `nil`.
	host *uvm.UtilityVM

	// ecl is the exec create lock for all non-init execs and MUST be held
	// during create to prevent ID duplication.
	ecl   sync.Mutex
	execs sync.Map

	closed    chan struct{}
	closeOnce sync.Once
	// closeHostOnce is used to close `host`. This will only be used if
	// `ownsHost==true` and `host != nil`.
	closeHostOnce sync.Once

	// taskSpec represents the spec/configuration for this task.
	taskSpec *specs.Spec

	// ioRetryTimeout is the time for how long to try reconnecting to stdio pipes from containerd.
	ioRetryTimeout time.Duration
}

func (ht *hcsTask) ID() string {
	return ht.id
}

func (ht *hcsTask) CreateExec(ctx context.Context, req *task.ExecProcessRequest, spec *specs.Process) error {
	ht.ecl.Lock()
	defer ht.ecl.Unlock()

	// If the task exists or we got a request for "" which is the init task
	// fail.
	if _, loaded := ht.execs.Load(req.ExecID); loaded || req.ExecID == "" {
		return errors.Wrapf(errdefs.ErrAlreadyExists, "exec: '%s' in task: '%s' already exists", req.ExecID, ht.id)
	}

	if ht.init.State() != shimExecStateRunning {
		return errors.Wrapf(errdefs.ErrFailedPrecondition, "exec: '' in task: '%s' must be running to create additional execs", ht.id)
	}

	io, err := cmd.NewUpstreamIO(ctx, req.ID, req.Stdout, req.Stderr, req.Stdin, req.Terminal, ht.ioRetryTimeout)
	if err != nil {
		return err
	}

	he := newHcsExec(
		ctx,
		ht.events,
		ht.id,
		ht.host,
		ht.c,
		req.ExecID,
		ht.init.Status().Bundle,
		ht.isWCOW,
		spec,
		io,
	)

	ht.execs.Store(req.ExecID, he)

	// Publish the created event
	return ht.events.publishEvent(
		ctx,
		runtime.TaskExecAddedEventTopic,
		&eventstypes.TaskExecAdded{
			ContainerID: ht.id,
			ExecID:      req.ExecID,
		})
}

func (ht *hcsTask) GetExec(eid string) (shimExec, error) {
	if eid == "" {
		return ht.init, nil
	}
	raw, loaded := ht.execs.Load(eid)
	if !loaded {
		return nil, errors.Wrapf(errdefs.ErrNotFound, "exec: '%s' in task: '%s' not found", eid, ht.id)
	}
	return raw.(shimExec), nil
}

func (ht *hcsTask) ListExecs() (_ []shimExec, err error) {
	var execs []shimExec
	ht.execs.Range(func(key, value interface{}) bool {
		wt, ok := value.(shimExec)
		if !ok {
			err = fmt.Errorf("failed to load exec %q", key)
			return false
		}
		execs = append(execs, wt)
		return true
	})
	if err != nil {
		return nil, err
	}
	return execs, nil
}

func (ht *hcsTask) KillExec(ctx context.Context, eid string, signal uint32, all bool) error {
	e, err := ht.GetExec(eid)
	if err != nil {
		return err
	}
	if all && eid != "" {
		return errors.Wrapf(errdefs.ErrFailedPrecondition, "cannot signal all for non-empty exec: '%s'", eid)
	}
	if all {
		// We are in a kill all on the init task. Signal everything.
		ht.execs.Range(func(key, value interface{}) bool {
			err := value.(shimExec).Kill(ctx, signal)
			if err != nil {
				log.G(ctx).WithFields(logrus.Fields{
					"eid":           key,
					logrus.ErrorKey: err,
				}).Warn("failed to kill exec in task")
			}

			// Iterate all. Returning false stops the iteration. See:
			// https://pkg.go.dev/sync#Map.Range
			return true
		})
	}
	if signal == 0x9 && eid == "" && ht.host != nil {
		// If this is a SIGKILL against the init process we start a background
		// timer and wait on either the timer expiring or the process exiting
		// cleanly. If the timer exires first we forcibly close the UVM as we
		// assume the guest is misbehaving for some reason.
		go func() {
			t := time.NewTimer(30 * time.Second)
			execExited := make(chan struct{})
			go func() {
				e.Wait()
				close(execExited)
			}()
			select {
			case <-execExited:
				t.Stop()
			case <-t.C:
				// Safe to call multiple times if called previously on
				// successful shutdown.
				ht.host.Close()
			}
		}()
	}
	return e.Kill(ctx, signal)
}

func (ht *hcsTask) DeleteExec(ctx context.Context, eid string) (int, uint32, time.Time, error) {
	e, err := ht.GetExec(eid)
	if err != nil {
		return 0, 0, time.Time{}, err
	}
	if eid == "" {
		// We are deleting the init exec. Forcibly exit any additional exec's.
		ht.execs.Range(func(key, value interface{}) bool {
			ex := value.(shimExec)
			if s := ex.State(); s != shimExecStateExited {
				ex.ForceExit(ctx, 1)
			}

			// Iterate all. Returning false stops the iteration. See:
			// https://pkg.go.dev/sync#Map.Range
			return true
		})
	}
	switch state := e.State(); state {
	case shimExecStateCreated:
		e.ForceExit(ctx, 0)
	case shimExecStateRunning:
		return 0, 0, time.Time{}, newExecInvalidStateError(ht.id, eid, state, "delete")
	}

	if eid == "" {
		// We are killing the init task, so we expect the container to be
		// stopped after this.
		//
		// The task process may have already exited, and the status set to
		// shimExecStateExited, but resources may still be in the process
		// of being cleaned up. Wait for ht.closed to be closed. This signals
		// that waitInitExit() has finished destroying container resources,
		// and layers were umounted.
		// If the shim exits before resources are cleaned up, those resources
		// will remain locked and untracked, which leads to lingering sandboxes
		// and container resources like base vhdx.
		select {
		case <-time.After(30 * time.Second):
			log.G(ctx).Error("timed out waiting for resource cleanup")
			return 0, 0, time.Time{}, errors.Wrap(hcs.ErrTimeout, "waiting for container resource cleanup")
		case <-ht.closed:
		}

		// The init task has now exited. A ForceExit() has already been sent to
		// execs. Cleanup execs and continue.
		ht.execs.Range(func(key, value interface{}) bool {
			if key == "" {
				// Iterate next.
				return true
			}
			ht.execs.Delete(key)

			// Iterate all. Returning false stops the iteration. See:
			// https://pkg.go.dev/sync#Map.Range
			return true
		})

		// cleanup the container directories inside the UVM if required.
		if ht.host != nil {
			if err := ht.host.DeleteContainerState(ctx, ht.id); err != nil {
				log.G(ctx).WithError(err).Errorf("failed to delete container state")
			}
		}
	}

	status := e.Status()
	if eid != "" {
		ht.execs.Delete(eid)
	}

	// Publish the deleted event
	if err := ht.events.publishEvent(
		ctx,
		runtime.TaskDeleteEventTopic,
		&eventstypes.TaskDelete{
			ContainerID: ht.id,
			ID:          eid,
			Pid:         status.Pid,
			ExitStatus:  status.ExitStatus,
			ExitedAt:    status.ExitedAt,
		}); err != nil {
		return 0, 0, time.Time{}, err
	}

	return int(status.Pid), status.ExitStatus, status.ExitedAt, nil
}

func (ht *hcsTask) Pids(ctx context.Context) ([]runhcsopts.ProcessDetails, error) {
	// Map all user created exec's to pid/exec-id
	pidMap := make(map[int]string)
	ht.execs.Range(func(key, value interface{}) bool {
		ex := value.(shimExec)
		pidMap[ex.Pid()] = ex.ID()

		// Iterate all. Returning false stops the iteration. See:
		// https://pkg.go.dev/sync#Map.Range
		return true
	})
	pidMap[ht.init.Pid()] = ht.init.ID()

	// Get the guest pids
	props, err := ht.c.Properties(ctx, schema1.PropertyTypeProcessList)
	if err != nil {
		if isStatsNotFound(err) {
			return nil, errors.Wrapf(errdefs.ErrNotFound, "failed to fetch pids: %s", err)
		}
		return nil, err
	}

	// Copy to pid/exec-id pair's
	pairs := make([]runhcsopts.ProcessDetails, len(props.ProcessList))
	for i, p := range props.ProcessList {
		pairs[i].ImageName = p.ImageName
		pairs[i].CreatedAt = p.CreateTimestamp
		pairs[i].KernelTime_100Ns = p.KernelTime100ns
		pairs[i].MemoryCommitBytes = p.MemoryCommitBytes
		pairs[i].MemoryWorkingSetPrivateBytes = p.MemoryWorkingSetPrivateBytes
		pairs[i].MemoryWorkingSetSharedBytes = p.MemoryWorkingSetSharedBytes
		pairs[i].ProcessID = p.ProcessId
		pairs[i].UserTime_100Ns = p.KernelTime100ns

		if eid, ok := pidMap[int(p.ProcessId)]; ok {
			pairs[i].ExecID = eid
		}
	}
	return pairs, nil
}

func (ht *hcsTask) Wait() *task.StateResponse {
	<-ht.closed
	return ht.init.Wait()
}

func (ht *hcsTask) waitInitExit() {
	ctx, span := oc.StartSpan(context.Background(), "hcsTask::waitInitExit")
	defer span.End()
	span.AddAttributes(trace.StringAttribute("tid", ht.id))

	// Wait for it to exit on its own
	ht.init.Wait()

	// Close the host and event the exit
	ht.close(ctx)
}

// waitForHostExit waits for the host virtual machine to exit. Once exited
// forcibly exits all additional exec's in this task.
//
// This MUST be called via a goroutine to wait on a background thread.
//
// Note: For Windows process isolated containers there is no host virtual
// machine so this should not be called.
func (ht *hcsTask) waitForHostExit() {
	ctx, span := oc.StartSpan(context.Background(), "hcsTask::waitForHostExit")
	defer span.End()
	span.AddAttributes(trace.StringAttribute("tid", ht.id))

	err := ht.host.Wait()
	if err != nil {
		log.G(ctx).WithError(err).Error("failed to wait for host virtual machine exit")
	} else {
		log.G(ctx).Debug("host virtual machine exited")
	}

	ht.execs.Range(func(key, value interface{}) bool {
		ex := value.(shimExec)
		ex.ForceExit(ctx, 1)

		// Iterate all. Returning false stops the iteration. See:
		// https://pkg.go.dev/sync#Map.Range
		return true
	})
	ht.init.ForceExit(ctx, 1)
	ht.closeHost(ctx)
}

// close shuts down the container that is owned by this task and if
// `ht.ownsHost` will shutdown the hosting VM the container was placed in.
//
// NOTE: For Windows process isolated containers `ht.ownsHost==true && ht.host
// == nil`.
func (ht *hcsTask) close(ctx context.Context) {
	ht.closeOnce.Do(func() {
		log.G(ctx).Debug("hcsTask::closeOnce")

		// ht.c should never be nil for a real task but in testing we stub
		// this to avoid a nil dereference. We really should introduce a
		// method or interface for ht.c operations that we can stub for
		// testing.
		if ht.c != nil {
			// Do our best attempt to tear down the container.
			var werr error
			ch := make(chan struct{})
			go func() {
				werr = ht.c.Wait()
				close(ch)
			}()
			err := ht.c.Shutdown(ctx)
			if err != nil {
				log.G(ctx).WithError(err).Error("failed to shutdown container")
			} else {
				t := time.NewTimer(time.Second * 30)
				select {
				case <-ch:
					err = werr
					t.Stop()
					if err != nil {
						log.G(ctx).WithError(err).Error("failed to wait for container shutdown")
					}
				case <-t.C:
					err = hcs.ErrTimeout
					log.G(ctx).WithError(err).Error("failed to wait for container shutdown")
				}
			}

			if err != nil {
				err = ht.c.Terminate(ctx)
				if err != nil {
					log.G(ctx).WithError(err).Error("failed to terminate container")
				} else {
					t := time.NewTimer(time.Second * 30)
					select {
					case <-ch:
						err = werr
						t.Stop()
						if err != nil {
							log.G(ctx).WithError(err).Error("failed to wait for container terminate")
						}
					case <-t.C:
						log.G(ctx).WithError(hcs.ErrTimeout).Error("failed to wait for container terminate")
					}
				}
			}

			// Release any resources associated with the container.
			if err := resources.ReleaseResources(ctx, ht.cr, ht.host, true); err != nil {
				log.G(ctx).WithError(err).Error("failed to release container resources")
			}

			// Close the container handle invalidating all future access.
			if err := ht.c.Close(); err != nil {
				log.G(ctx).WithError(err).Error("failed to close container")
			}
		}
		ht.closeHost(ctx)
	})
}

// closeHost safely closes the hosting UVM if this task is the owner. Once
// closed and all resources released it events the `runtime.TaskExitEventTopic`
// for all upstream listeners.
//
// Note: If this is a process isolated task the hosting UVM is simply a `noop`.
//
// This call is idempotent and safe to call multiple times.
func (ht *hcsTask) closeHost(ctx context.Context) {
	ht.closeHostOnce.Do(func() {
		log.G(ctx).Debug("hcsTask::closeHostOnce")

		if ht.ownsHost && ht.host != nil {
			if err := ht.host.Close(); err != nil {
				log.G(ctx).WithError(err).Error("failed host vm shutdown")
			}
		}
		// Send the `init` exec exit notification always.
		exit := ht.init.Status()

		if err := ht.events.publishEvent(
			ctx,
			runtime.TaskExitEventTopic,
			&eventstypes.TaskExit{
				ContainerID: ht.id,
				ID:          exit.ID,
				Pid:         uint32(exit.Pid),
				ExitStatus:  exit.ExitStatus,
				ExitedAt:    exit.ExitedAt,
			}); err != nil {
			log.G(ctx).WithError(err).Error("failed to publish TaskExitEventTopic")
		}
		close(ht.closed)
	})
}

func (ht *hcsTask) ExecInHost(ctx context.Context, req *shimdiag.ExecProcessRequest) (int, error) {
	cmdReq := &cmd.CmdProcessRequest{
		Args:     req.Args,
		Workdir:  req.Workdir,
		Terminal: req.Terminal,
		Stdin:    req.Stdin,
		Stdout:   req.Stdout,
		Stderr:   req.Stderr,
	}

	if ht.host == nil {
		return cmd.ExecInShimHost(ctx, cmdReq)
	}
	return cmd.ExecInUvm(ctx, ht.host, cmdReq)
}

func (ht *hcsTask) DumpGuestStacks(ctx context.Context) string {
	if ht.host != nil {
		stacks, err := ht.host.DumpStacks(ctx)
		if err != nil {
			log.G(ctx).WithError(err).Warn("failed to capture guest stacks")
		} else {
			return stacks
		}
	}
	return ""
}

func (ht *hcsTask) Share(ctx context.Context, req *shimdiag.ShareRequest) error {
	if ht.host == nil {
		return errTaskNotIsolated
	}
	return ht.host.Share(ctx, req.HostPath, req.UvmPath, req.ReadOnly)
}

func hcsPropertiesToWindowsStats(props *hcsschema.Properties) *stats.Statistics_Windows {
	wcs := &stats.Statistics_Windows{Windows: &stats.WindowsContainerStatistics{}}
	if props.Statistics != nil {
		wcs.Windows.Timestamp = props.Statistics.Timestamp
		wcs.Windows.ContainerStartTime = props.Statistics.ContainerStartTime
		wcs.Windows.UptimeNS = props.Statistics.Uptime100ns * 100
		if props.Statistics.Processor != nil {
			wcs.Windows.Processor = &stats.WindowsContainerProcessorStatistics{
				TotalRuntimeNS:  props.Statistics.Processor.TotalRuntime100ns * 100,
				RuntimeUserNS:   props.Statistics.Processor.RuntimeUser100ns * 100,
				RuntimeKernelNS: props.Statistics.Processor.RuntimeKernel100ns * 100,
			}
		}
		if props.Statistics.Memory != nil {
			wcs.Windows.Memory = &stats.WindowsContainerMemoryStatistics{
				MemoryUsageCommitBytes:            props.Statistics.Memory.MemoryUsageCommitBytes,
				MemoryUsageCommitPeakBytes:        props.Statistics.Memory.MemoryUsageCommitPeakBytes,
				MemoryUsagePrivateWorkingSetBytes: props.Statistics.Memory.MemoryUsagePrivateWorkingSetBytes,
			}
		}
		if props.Statistics.Storage != nil {
			wcs.Windows.Storage = &stats.WindowsContainerStorageStatistics{
				ReadCountNormalized:  props.Statistics.Storage.ReadCountNormalized,
				ReadSizeBytes:        props.Statistics.Storage.ReadSizeBytes,
				WriteCountNormalized: props.Statistics.Storage.WriteCountNormalized,
				WriteSizeBytes:       props.Statistics.Storage.WriteSizeBytes,
			}
		}
	}
	return wcs
}

func (ht *hcsTask) Stats(ctx context.Context) (*stats.Statistics, error) {
	s := &stats.Statistics{}
	props, err := ht.c.PropertiesV2(ctx, hcsschema.PTStatistics)
	if err != nil {
		if isStatsNotFound(err) {
			return nil, errors.Wrapf(errdefs.ErrNotFound, "failed to fetch stats: %s", err)
		}
		return nil, err
	}

	if props != nil {
		if ht.isWCOW {
			s.Container = hcsPropertiesToWindowsStats(props)
		} else {
			s.Container = &stats.Statistics_Linux{Linux: props.Metrics}
		}
	}
	if ht.ownsHost && ht.host != nil {
		vmStats, err := ht.host.Stats(ctx)
		if err != nil && !isStatsNotFound(err) {
			return nil, err
		}
		s.VM = vmStats
	}
	return s, nil
}

func (ht *hcsTask) Update(ctx context.Context, req *task.UpdateTaskRequest) error {
	resources, err := typeurl.UnmarshalAny(req.Resources)
	if err != nil {
		return errors.Wrapf(err, "failed to unmarshal resources for container %s update request", req.ID)
	}

	if err := verifyTaskUpdateResourcesType(resources); err != nil {
		return err
	}

	if ht.ownsHost && ht.host != nil {
		return ht.host.Update(ctx, resources, req.Annotations)
	}

	return ht.updateTaskContainerResources(ctx, resources, req.Annotations)
}

func (ht *hcsTask) updateTaskContainerResources(ctx context.Context, data interface{}, annotations map[string]string) error {
	if ht.isWCOW {
		switch resources := data.(type) {
		case *specs.WindowsResources:
			return ht.updateWCOWResources(ctx, resources, annotations)
		case *ctrdtaskapi.ContainerMount:
			// Adding mount to a running container is currently only supported for windows containers
			return ht.updateWCOWContainerMount(ctx, resources, annotations)
		default:
			return errNotSupportedResourcesRequest
		}
	}

	return ht.updateLCOWResources(ctx, data, annotations)
}

func (ht *hcsTask) updateWCOWContainerCPU(ctx context.Context, cpu *specs.WindowsCPUResources) error {
	// if host is 20h2+ then we can make a request directly to hcs
	if osversion.Get().Build >= osversion.V20H2 {
		req := &hcsschema.Processor{}
		if cpu.Count != nil {
			procCount := int32(*cpu.Count)
			hostProcs := processorinfo.ProcessorCount()
			if ht.host != nil {
				hostProcs = ht.host.ProcessorCount()
			}
			req.Count = hcsoci.NormalizeProcessorCount(ctx, ht.id, procCount, hostProcs)
		}
		if cpu.Maximum != nil {
			req.Maximum = int32(*cpu.Maximum)
		}
		if cpu.Shares != nil {
			req.Weight = int32(*cpu.Shares)
		}
		return ht.requestUpdateContainer(ctx, resourcepaths.SiloProcessorResourcePath, req)
	}

	return errdefs.ErrNotImplemented
}

func isValidWindowsCPUResources(c *specs.WindowsCPUResources) bool {
	return (c.Count != nil && (c.Shares == nil && c.Maximum == nil)) ||
		(c.Shares != nil && (c.Count == nil && c.Maximum == nil)) ||
		(c.Maximum != nil && (c.Count == nil && c.Shares == nil))
}

func (ht *hcsTask) updateWCOWResources(ctx context.Context, resources *specs.WindowsResources, annotations map[string]string) error {
	if resources.Memory != nil && resources.Memory.Limit != nil {
		newMemorySizeInMB := *resources.Memory.Limit / memory.MiB
		memoryLimit := hcsoci.NormalizeMemorySize(ctx, ht.id, newMemorySizeInMB)
		if err := ht.requestUpdateContainer(ctx, resourcepaths.SiloMemoryResourcePath, memoryLimit); err != nil {
			return err
		}
	}
	if resources.CPU != nil {
		if !isValidWindowsCPUResources(resources.CPU) {
			return fmt.Errorf("invalid cpu resources request for container %s: %v", ht.id, resources.CPU)
		}
		if err := ht.updateWCOWContainerCPU(ctx, resources.CPU); err != nil {
			return err
		}
	}
	return nil
}

func (ht *hcsTask) updateLCOWResources(ctx context.Context, data interface{}, annotations map[string]string) error {
	resources, ok := data.(*specs.LinuxResources)
	if !ok || resources == nil {
		return errors.New("must have resources be non-nil and type *LinuxResources when updating a lcow container")
	}
	settings := guestresource.LCOWContainerConstraints{
		Linux: *resources,
	}
	return ht.requestUpdateContainer(ctx, "", settings)
}

func (ht *hcsTask) requestUpdateContainer(ctx context.Context, resourcePath string, settings interface{}) error {
	var modification interface{}
	if ht.isWCOW {
		modification = &hcsschema.ModifySettingRequest{
			ResourcePath: resourcePath,
			RequestType:  guestrequest.RequestTypeUpdate,
			Settings:     settings,
		}
	} else {
		modification = guestrequest.ModificationRequest{
			ResourceType: guestresource.ResourceTypeContainerConstraints,
			RequestType:  guestrequest.RequestTypeUpdate,
			Settings:     settings,
		}
	}
	return ht.c.Modify(ctx, modification)
}

func (ht *hcsTask) ProcessorInfo(ctx context.Context) (*processorInfo, error) {
	if ht.host == nil {
		return nil, errTaskNotIsolated
	}
	if !ht.ownsHost {
		return nil, errors.New("not implemented")
	}
	return &processorInfo{
		count: ht.host.ProcessorCount(),
	}, nil
}

func (ht *hcsTask) requestAddContainerMount(ctx context.Context, resourcePath string, settings interface{}) error {
	modification := &hcsschema.ModifySettingRequest{
		ResourcePath: resourcePath,
		RequestType:  guestrequest.RequestTypeAdd,
		Settings:     settings,
	}
	return ht.c.Modify(ctx, modification)
}

func isMountTypeSupported(hostPath, mountType string) bool {
	// currently we only support mounting of host volumes/directories
	switch mountType {
	case hcsoci.MountTypeBind, hcsoci.MountTypePhysicalDisk,
		hcsoci.MountTypeVirtualDisk, hcsoci.MountTypeExtensibleVirtualDisk:
		return false
	default:
		// Ensure that host path is not sandbox://, hugepages://
		if strings.HasPrefix(hostPath, guestpath.SandboxMountPrefix) ||
			strings.HasPrefix(hostPath, guestpath.HugePagesMountPrefix) ||
			strings.HasPrefix(hostPath, guestpath.PipePrefix) {
			return false
		} else {
			// hcsshim treats mountType == "" as a normal directory mount
			// and this is supported
			return mountType == ""
		}
	}
}

func (ht *hcsTask) updateWCOWContainerMount(ctx context.Context, resources *ctrdtaskapi.ContainerMount, annotations map[string]string) error {
	// Hcsschema v2 should be supported
	if osversion.Build() < osversion.RS5 {
		// OSVerions < RS5 only support hcsshema v1
		return fmt.Errorf("hcsschema v1 unsupported")
	}

	if resources.HostPath == "" || resources.ContainerPath == "" {
		return fmt.Errorf("invalid OCI spec - a mount must have both host and container path set")
	}

	// Check for valid mount type
	if !isMountTypeSupported(resources.HostPath, resources.Type) {
		return fmt.Errorf("invalid mount type %v. Currently only host volumes/directories can be mounted to running containers", resources.Type)
	}

	if ht.host == nil {
		// HCS has a bug where it does not correctly resolve file (not dir) paths
		// if the path includes a symlink. Therefore, we resolve the path here before
		// passing it in. The issue does not occur with VSMB, so don't need to worry
		// about the isolated case.
		hostPath, err := fs.ResolvePath(resources.HostPath)
		if err != nil {
			return errors.Wrapf(err, "failed to resolve path for hostPath %s", resources.HostPath)
		}

		// process isolated windows container
		settings := hcsschema.MappedDirectory{
			HostPath:      hostPath,
			ContainerPath: resources.ContainerPath,
			ReadOnly:      resources.ReadOnly,
		}
		if err := ht.requestAddContainerMount(ctx, resourcepaths.SiloMappedDirectoryResourcePath, settings); err != nil {
			return errors.Wrapf(err, "failed to add mount to process isolated container")
		}
	} else {
		// if it is a mount request for a running hyperV WCOW container, we should first mount volume to the
		// UVM as a VSMB share and then mount to the running container using the src path as seen by the UVM
		vsmbShare, guestPath, err := ht.host.AddVsmbAndGetSharePath(ctx, resources.HostPath, resources.ContainerPath, resources.ReadOnly)
		if err != nil {
			return err
		}
		// Add mount to list of resources to be released on container cleanup
		ht.cr.Add(vsmbShare)

		settings := hcsschema.MappedDirectory{
			HostPath:      guestPath,
			ContainerPath: resources.ContainerPath,
			ReadOnly:      resources.ReadOnly,
		}
		if err := ht.requestAddContainerMount(ctx, resourcepaths.SiloMappedDirectoryResourcePath, settings); err != nil {
			return errors.Wrapf(err, "failed to add mount to hyperV container")
		}
	}
	return nil
}