package daemon
 
 import (
 	"fmt"
 	"os"

 	"unsafe"

 	winio "github.com/Microsoft/go-winio"

 	"github.com/docker/docker/pkg/signal"

 	"github.com/sirupsen/logrus"

 	"golang.org/x/sys/windows"

 )
 

 func (d *Daemon) setupDumpStackTrap(root string) {

 	// Windows does not support signals like *nix systems. So instead of
 	// trapping on SIGUSR1 to dump stacks, we wait on a Win32 event to be

 	// signaled. ACL'd to builtin administrators and local system

 	event := "Global\\docker-daemon-" + fmt.Sprint(os.Getpid())
 	ev, _ := windows.UTF16PtrFromString(event)

 	sd, err := winio.SddlToSecurityDescriptor("D:P(A;;GA;;;BA)(A;;GA;;;SY)")
 	if err != nil {

 		logrus.Errorf("failed to get security descriptor for debug stackdump event %s: %s", event, err.Error())

 		return
 	}

 	var sa windows.SecurityAttributes

 	sa.Length = uint32(unsafe.Sizeof(sa))
 	sa.InheritHandle = 1
 	sa.SecurityDescriptor = uintptr(unsafe.Pointer(&sd[0]))

 	h, err := windows.CreateEvent(&sa, 0, 0, ev)

 	if h == 0 || err != nil {

 		logrus.Errorf("failed to create debug stackdump event %s: %s", event, err.Error())

 		return
 	}

 	go func() {

 		logrus.Debugf("Stackdump - waiting signal at %s", event)

 		for {

 			windows.WaitForSingleObject(h, windows.INFINITE)

 			path, err := signal.DumpStacks(root)
 			if err != nil {
 				logrus.WithError(err).Error("failed to write goroutines dump")

 			} else {
 				logrus.Infof("goroutine stacks written to %s", path)
 			}

 		}
 	}()
 }