Go lang set windows events hooks - windows

Question

Hi am trying to set a global event hook in go but i dont get the event handle or any error message , kindly help , below is code , from my code below i expected to get error message from SetWinEventHook if any but it just blocks at Logger.Println("procSetWinEventHook S") please not that i have not included my custo Logger but thats not a blocker.
package main
import(
"fmt"
"syscall"
"unsafe"
"log"
"golang.org/x/sys/windows"
)
var(
user32 = windows.NewLazyDLL("user32.dll")
modkernel32 = windows.NewLazyDLL("kernel32.dll")
procSetWinEventHook = user32.NewProc("SetWinEventHook")
procUnhookWinEvent = user32.NewProc("UnhookWinEvent")
procGetMessage = user32.NewProc("GetMessageW")
procTranslateMessage = user32.NewProc("TranslateMessage")
procDispatchMessage = user32.NewProc("DispatchMessageW")
procGetModuleHandle = modkernel32.NewProc("GetModuleHandleW")
ActiveWinEventHook WINEVENTPROC = func (hWinEventHook HWINEVENTHOOK, event uint32, hwnd HWND, idObject int32, idChild int32, idEventThread uint32, dwmsEventTime uint32) {
log.Println("fond")
}
)
type WINEVENTPROC func(hWinEventHook HWINEVENTHOOK, event uint32, hwnd HWND, idObject int32, idChild int32, idEventThread uint32, dwmsEventTime uint32) uintptr
type (
HANDLE uintptr
HINSTANCE HANDLE
HHOOK HANDLE
HMODULE HANDLE
HWINEVENTHOOK HANDLE
DWORD uint32
INT int
WPARAM uintptr
LPARAM uintptr
LRESULT uintptr
HWND HANDLE
UINT uint32
BOOL int32
ULONG_PTR uintptr
LONG int32
LPWSTR *WCHAR
WCHAR uint16
)
type POINT struct {
X, Y int32
}
type MSG struct {
Hwnd HWND
Message uint32
WParam uintptr
LParam uintptr
Time uint32
Pt POINT
}
const (
//~ EVENT_SYSTEM_FOREGROUND DWORD = 0x0003
//~ WINEVENT_OUTOFCONTEXT DWORD = 0x0000
//~ WINEVENT_INCONTEXT = 0x0004
EVENT_SYSTEM_FOREGROUND = 3
WINEVENT_OUTOFCONTEXT = 0
WINEVENT_INCONTEXT = 4
WINEVENT_SKIPOWNPROCESS = 2
WINEVENT_SKIPOWNTHREAD = 1
)
func main() {
log.Println("starting")
hinst := GetModuleHandle("")
fmt.Println(hinst)
winEvHook := SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, 0 , ActiveWinEventHook, 0, 0, WINEVENT_OUTOFCONTEXT|WINEVENT_SKIPOWNPROCESS )
log.Println("Windows Event Hook: ")
log.Println("Windows Event Hook: ", winEvHook)
for {
var msg MSG
if m := GetMessage(&msg, 0, 0, 0); m != 0 {
TranslateMessage(&msg)
DispatchMessage(&msg)
}
}
UnhookWinEvent(winEvHook)
return
}
func SetWinEventHook(eventMin DWORD, eventMax DWORD, hmodWinEventProc HMODULE, pfnWinEventProc WINEVENTPROC, idProcess DWORD, idThread DWORD, dwFlags DWORD) HWINEVENTHOOK {
log.Println("procSetWinEventHook S")
ret, ret2 , err := procSetWinEventHook.Call(
uintptr(eventMin),
uintptr(eventMax),
uintptr(hmodWinEventProc),
pfnWinEventProcCallback,
uintptr(idProcess),
uintptr(idThread),
uintptr(dwFlags),
)
log.Printf("%#v", err)
log.Printf("%#v", ret)
log.Printf("%#v", ret2)
log.Println("procSetWinEventHook E")
return HWINEVENTHOOK(ret)
}
func UnhookWinEvent(hWinEventHook HWINEVENTHOOK) bool {
ret, _, _ := procUnhookWinEvent.Call(
uintptr(hWinEventHook),
)
return ret != 0
}
func GetModuleHandle(modulename string) HINSTANCE {
var mn uintptr
if modulename == "" {
mn = 0
} else {
mn = uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(modulename)))
}
ret, _, _ := procGetModuleHandle.Call(mn)
return HINSTANCE(ret)
}
func GetMessage(msg *MSG, hwnd HWND, msgFilterMin UINT, msgFilterMax UINT) int {
ret, _, _ := procGetMessage.Call(
uintptr(unsafe.Pointer(msg)),
uintptr(hwnd),
uintptr(msgFilterMin),
uintptr(msgFilterMax))
return int(ret)
}
func TranslateMessage(msg *MSG) bool {
ret, _, _ := procTranslateMessage.Call(
uintptr(unsafe.Pointer(msg)))
return ret != 0
}
func DispatchMessage(msg *MSG) uintptr {
ret, _, _ := procDispatchMessage.Call(
uintptr(unsafe.Pointer(msg)))
return ret
}

Answer 1

So after research i noticed that
syscall.NewCallback() required an output value , for WinEventProc however from MSDN , the callback WinEventProc didn't return any value , so a "forced" a return value of type uintptr and worked perfectly.Like below code :
package main
import(
"fmt"
"syscall"
"unsafe"
"log"
"golang.org/x/sys/windows"
)
var(
user32 = windows.NewLazyDLL("user32.dll")
modkernel32 = windows.NewLazyDLL("kernel32.dll")
procSetWinEventHook = user32.NewProc("SetWinEventHook")
procUnhookWinEvent = user32.NewProc("UnhookWinEvent")
procGetMessage = user32.NewProc("GetMessageW")
procTranslateMessage = user32.NewProc("TranslateMessage")
procDispatchMessage = user32.NewProc("DispatchMessageW")
procGetModuleHandle = modkernel32.NewProc("GetModuleHandleW")
ActiveWinEventHook WINEVENTPROC = func (hWinEventHook HWINEVENTHOOK, event uint32, hwnd HWND, idObject int32, idChild int32, idEventThread uint32, dwmsEventTime uint32) uintptr {
log.Println("fond")
}
)
type WINEVENTPROC func(hWinEventHook HWINEVENTHOOK, event uint32, hwnd HWND, idObject int32, idChild int32, idEventThread uint32, dwmsEventTime uint32) uintptr
type (
HANDLE uintptr
HINSTANCE HANDLE
HHOOK HANDLE
HMODULE HANDLE
HWINEVENTHOOK HANDLE
DWORD uint32
INT int
WPARAM uintptr
LPARAM uintptr
LRESULT uintptr
HWND HANDLE
UINT uint32
BOOL int32
ULONG_PTR uintptr
LONG int32
LPWSTR *WCHAR
WCHAR uint16
)
type POINT struct {
X, Y int32
}
type MSG struct {
Hwnd HWND
Message uint32
WParam uintptr
LParam uintptr
Time uint32
Pt POINT
}
const (
//~ EVENT_SYSTEM_FOREGROUND DWORD = 0x0003
//~ WINEVENT_OUTOFCONTEXT DWORD = 0x0000
//~ WINEVENT_INCONTEXT = 0x0004
EVENT_SYSTEM_FOREGROUND = 3
WINEVENT_OUTOFCONTEXT = 0
WINEVENT_INCONTEXT = 4
WINEVENT_SKIPOWNPROCESS = 2
WINEVENT_SKIPOWNTHREAD = 1
)
func main() {
log.Println("starting")
hinst := GetModuleHandle("")
fmt.Println(hinst)
winEvHook := SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, 0 , ActiveWinEventHook, 0, 0, WINEVENT_OUTOFCONTEXT|WINEVENT_SKIPOWNPROCESS )
log.Println("Windows Event Hook: ")
log.Println("Windows Event Hook: ", winEvHook)
for {
var msg MSG
if m := GetMessage(&msg, 0, 0, 0); m != 0 {
TranslateMessage(&msg)
DispatchMessage(&msg)
}
}
UnhookWinEvent(winEvHook)
return
}
func SetWinEventHook(eventMin DWORD, eventMax DWORD, hmodWinEventProc HMODULE, pfnWinEventProc WINEVENTPROC, idProcess DWORD, idThread DWORD, dwFlags DWORD) HWINEVENTHOOK {
log.Println("procSetWinEventHook S")
pfnWinEventProcCallback := syscall.NewCallback(pfnWinEventProc)
ret, ret2 , err := procSetWinEventHook.Call(
uintptr(eventMin),
uintptr(eventMax),
uintptr(hmodWinEventProc),
pfnWinEventProcCallback,
uintptr(idProcess),
uintptr(idThread),
uintptr(dwFlags),
)
log.Printf("%#v", err)
log.Printf("%#v", ret)
log.Printf("%#v", ret2)
log.Println("procSetWinEventHook E")
return HWINEVENTHOOK(ret)
}
func UnhookWinEvent(hWinEventHook HWINEVENTHOOK) bool {
ret, _, _ := procUnhookWinEvent.Call(
uintptr(hWinEventHook),
)
return ret != 0
}
func GetModuleHandle(modulename string) HINSTANCE {
var mn uintptr
if modulename == "" {
mn = 0
} else {
mn = uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(modulename)))
}
ret, _, _ := procGetModuleHandle.Call(mn)
return HINSTANCE(ret)
}
func GetMessage(msg *MSG, hwnd HWND, msgFilterMin UINT, msgFilterMax UINT) int {
ret, _, _ := procGetMessage.Call(
uintptr(unsafe.Pointer(msg)),
uintptr(hwnd),
uintptr(msgFilterMin),
uintptr(msgFilterMax))
return int(ret)
}
func TranslateMessage(msg *MSG) bool {
ret, _, _ := procTranslateMessage.Call(
uintptr(unsafe.Pointer(msg)))
return ret != 0
}
func DispatchMessage(msg *MSG) uintptr {
ret, _, _ := procDispatchMessage.Call(
uintptr(unsafe.Pointer(msg)))
return ret
}