dotcloud/docker

package daemon // import "github.com/docker/docker/daemon"

import (
    "context"
    "fmt"
    "os"
    "unsafe"

    "github.com/containerd/log"
    "github.com/docker/docker/pkg/stack"
    "golang.org/x/sys/windows"
)

func (daemon *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\\stackdump-" + fmt.Sprint(os.Getpid())
    ev, _ := windows.UTF16PtrFromString(event)
    sd, err := windows.SecurityDescriptorFromString("D:P(A;;GA;;;BA)(A;;GA;;;SY)")
    if err != nil {
        log.G(context.TODO()).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 = sd
    h, err := windows.CreateEvent(&sa, 0, 0, ev)
    if h == 0 || err != nil {
        log.G(context.TODO()).Errorf("failed to create debug stackdump event %s: %s", event, err.Error())
        return
    }
    go func() {
        log.G(context.TODO()).Debugf("Stackdump - waiting signal at %s", event)
        for {
            windows.WaitForSingleObject(h, windows.INFINITE)
            path, err := stack.DumpToFile(root)
            if err != nil {
                log.G(context.TODO()).WithError(err).Error("failed to write goroutines dump")
            } else {
                log.G(context.TODO()).Infof("goroutine stacks written to %s", path)
            }
        }
    }()
}