Win32 CodeHook

Document of interface IDirectCodeHook

This interface is for raw mode hooking.
You usually should use ICodeHook's raw mode hooking feature instead of use this interface directly.
To get the interface, call ICodeHook.GetDirectCodeHook;

Delphi syntax:

IDirectCodeHook = interface(IErrorCodeHook)
	function Hook(ATarget, AHook: Pointer; APreviousMethod: Pointer): LongBool; stdcall;
	function Unhook(ATarget: Pointer; APreviousMethod: Pointer): LongBool; stdcall;
	function AllocatePreviousMethodMemory: Pointer; stdcall;
	procedure FreePreviousMethodMemory(APreviousMethod: Pointer); stdcall;
end;

C++ syntax:

class IDirectCodeHook: public ICodeHookError {
public:
	virtual BOOL _stdcall Hook(Pointer Target, Pointer Hook, Pointer OldFunc) = 0;
	virtual BOOL _stdcall Unhook(Pointer Target, Pointer AOldFunc) = 0;
	virtual void * _stdcall AllocatePreviousMethodMemory() = 0;
	virtual void FreePreviousMethodMemory(Pointer OldFunc) = 0;
};

Function:

Hook

Low level hook a method.
Delphi syntax:

function Hook(ATarget, AHook: Pointer; APreviousMethod: Pointer): LongBool; stdcall;

C++ syntax:

virtual BOOL calltype Hook(Pointer Target, Pointer Hook, Pointer OldFunc) = 0;

Params

ATarget: Address of the target function.
AHook: Address of the hook function.
APreviousMethod: Pointer to a memory block to store the previous method information. You may use IDirectCodeHook.AllocatePreviousMethodMemory to allocate memory.

Return value

Return TRUE on success, otherwise, return FALSE.

Remarks

Don't use this function, instead, use ICodeHook.Hook.

Function:

Unhook

Low level unhook a method.
Delphi syntax:

function Unhook(ATarget: Pointer; APreviousMethod: Pointer): LongBool; stdcall;

C++ syntax:

virtual BOOL calltype Unhook(Pointer Target, Pointer AOldFunc) = 0;

Params

ATarget: Address of the target function.
APreviousMethod: Address of the previous function.

Return value

Return TRUE on success, otherwise, return FALSE.

Remarks

Don't use this function, instead, use ICodeHook.Unhook.

Function:

AllocatePreviousMethodMemory

Allocate a block of memory to store previous method information.
Delphi syntax:

function AllocatePreviousMethodMemory: Pointer; stdcall;

C++ syntax:

virtual void * calltype AllocatePreviousMethodMemory() = 0;

Params

This function has no parameters.

Return value

Return the memory pointer.

Remarks

You can pass the return value to IDirectCodeHook.Hook and IDirectCodeHook.Unhook.

Function:

FreePreviousMethodMemory

Free the memory block.
Delphi syntax:

procedure FreePreviousMethodMemory(APreviousMethod: Pointer); stdcall;

C++ syntax:

virtual void FreePreviousMethodMemory(Pointer OldFunc) = 0;

Params

APreviousMethod: Pointer that returned by IDirectCodeHook.AllocatePreviousMethodMemory

Return value

This function doesn't return value.