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| 1 | +package main |
| 2 | + |
| 3 | +// Very simple utility which signals an event. Used to signal a docker |
| 4 | +// daemon on Windows to dump its stacks. Usage docker-signal --pid=daemonpid |
| 5 | + |
| 6 | +import ( |
| 7 | + "flag" |
| 8 | + "fmt" |
| 9 | + "syscall" |
| 10 | + "unsafe" |
| 11 | +) |
| 12 | + |
| 13 | +const EVENT_MODIFY_STATUS = 0x0002 |
| 14 | + |
| 15 | +var ( |
| 16 | + modkernel32 = syscall.NewLazyDLL("kernel32.dll") |
| 17 | + procOpenEvent = modkernel32.NewProc("OpenEventW") |
| 18 | + procPulseEvent = modkernel32.NewProc("PulseEvent") |
| 19 | +) |
| 20 | + |
| 21 | +func OpenEvent(desiredAccess uint32, inheritHandle bool, name string) (handle syscall.Handle, err error) { |
| 22 | + namep, _ := syscall.UTF16PtrFromString(name) |
| 23 | + var _p2 uint32 = 0 |
| 24 | + if inheritHandle { |
| 25 | + _p2 = 1 |
| 26 | + } |
| 27 | + r0, _, e1 := procOpenEvent.Call(uintptr(desiredAccess), uintptr(_p2), uintptr(unsafe.Pointer(namep))) |
| 28 | + use(unsafe.Pointer(namep)) |
| 29 | + handle = syscall.Handle(r0) |
| 30 | + if handle == syscall.InvalidHandle { |
| 31 | + err = e1 |
| 32 | + } |
| 33 | + return |
| 34 | +} |
| 35 | + |
| 36 | +func PulseEvent(handle syscall.Handle) (err error) { |
| 37 | + r0, _, _ := procPulseEvent.Call(uintptr(handle)) |
| 38 | + if r0 != 0 { |
| 39 | + err = syscall.Errno(r0) |
| 40 | + } |
| 41 | + return |
| 42 | +} |
| 43 | + |
| 44 | +func main() { |
| 45 | + var pid int |
| 46 | + flag.IntVar(&pid, "pid", -1, "PID of docker daemon to signal to dump stacks") |
| 47 | + flag.Parse() |
| 48 | + if pid == -1 { |
| 49 | + fmt.Println("Error: pid must be supplied") |
| 50 | + return |
| 51 | + } |
| 52 | + ev := "Global\\docker-daemon-" + fmt.Sprint(pid) |
| 53 | + h2, _ := OpenEvent(EVENT_MODIFY_STATUS, false, ev) |
| 54 | + if h2 == 0 { |
| 55 | + fmt.Printf("Could not open event. Check PID %d is correct and the daemon is running.\n", pid) |
| 56 | + return |
| 57 | + } |
| 58 | + PulseEvent(h2) |
| 59 | + fmt.Println("Daemon signalled successfully. Examine its output for stacks") |
| 60 | +} |
| 61 | + |
| 62 | +var temp unsafe.Pointer |
| 63 | + |
| 64 | +func use(p unsafe.Pointer) { |
| 65 | + temp = p |
| 66 | +} |
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