myapidll.dpr

制作API钩子,截获API的源码

{*********************************************
 * APIHOOK演示程序之动态链接库               *
 * 王锐（武稀松wr960204）                    *
 * 2002.2.6                                  *
 *********************************************}
library MYAPIDLL;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
   SysUtils,
   Windows,
   Classes,
   HookAPI in 'HookAPI.pas';

type
   TTextOutA = function(DC: HDC; X, Y: Integer; Str: PAnsiChar; Count: Integer): BOOL; stdcall;
   TTextOutW = function(DC: HDC; X, Y: Integer; Str: PWideChar; Count: Integer): BOOL; stdcall;
   TTextOut = function(DC: HDC; X, Y: Integer; Str: PChar; Count: Integer): BOOL; stdcall;
   TDrawTextA = function(hDC: HDC; lpString: PAnsiChar; nCount: Integer; var lpRect: TRect; uFormat: UINT): Integer; stdcall;
   TDrawTextW = function(hDC: HDC; lpString: PWideChar; nCount: Integer; var lpRect: TRect; uFormat: UINT): Integer; stdcall;
   TDrawText = function(hDC: HDC; lpString: PChar; nCount: Integer; var lpRect: TRect; uFormat: UINT): Integer; stdcall;
var
   OldTextOutA: TTextOutA;
   OldTextOutW: TTextOutW;
   OldTextOut: TTextOut;
   OldDrawTextA: TDrawTextA;
   OldDrawTextW: TDrawTextW;
   OldDrawText: TDrawText;

   {$R *.RES}

function MyTextOutA(DC: HDC; X, Y: Integer; Str: PAnsiChar; Count: Integer): BOOL; stdcall;
begin
   OldTextOutA(DC, X, Y, 'ABC', length('ABC'));
end;

function MyTextOutW(DC: HDC; X, Y: Integer; Str: PWideChar; Count: Integer): BOOL; stdcall;
begin
   OldTextOutW(DC, X, Y, 'ABC', length('ABC'));
end;

function MyTextOut(DC: HDC; X, Y: Integer; Str: PChar; Count: Integer): BOOL; stdcall;
begin
   OldTextOut(DC, X, Y, 'ABC', length('ABC'));
end;

function MyDrawTextA(hDC: HDC; lpString: PAnsiChar; nCount: Integer; var lpRect: TRect; uFormat: UINT): Integer; stdcall;
begin
   OldDrawTextA(hDC, 'ABC', length('ABC'), lpRect, uFormat);
end;

function MyDrawTextW(hDC: HDC; lpString: PWideChar; nCount: Integer; var lpRect: TRect; uFormat: UINT): Integer; stdcall;
begin
   OldDrawTextW(hDC, 'ABC', length('ABC'), lpRect, uFormat);
end;

function MyDrawText(hDC: HDC; lpString: PChar; nCount: Integer; var lpRect: TRect; uFormat: UINT): Integer; stdcall;
begin
   OldDrawText(hDC, 'ABC', length('ABC'), lpRect, uFormat);
end;

procedure API_Hookup; stdcall;
begin
   if @OldTextOutA = nil then
      @OldTextOutA := LocateFunctionAddress(@TextOutA);
   if @OldTextOutW = nil then
      @OldTextOutW := LocateFunctionAddress(@TextOutW);
   if @OldTextOut = nil then
      @OldTextOut := LocateFunctionAddress(@TextOut);
   if @OldDrawTextA = nil then
      @OldDrawTextA := LocateFunctionAddress(@DrawTextA);
   if @OldDrawTextW = nil then
      @OldDrawTextW := LocateFunctionAddress(@DrawTextW);
   if @OldDrawText = nil then
      @OldDrawText := LocateFunctionAddress(@DrawText);

   RepointFunction(@OldTextOutA, @MyTextOutA);
   RepointFunction(@OldTextOutW, @MyTextOutW);
   RepointFunction(@OldTextOut, @MyTextOut);
   RepointFunction(@OldDrawTextA, @MyDrawTextA);
   RepointFunction(@OldDrawTextW, @MyDrawTextW);
   RepointFunction(@OldDrawText, @MyDrawText);

end;

procedure API_HookDown; stdcall;
begin
   if @OldTextOutA <> nil then
   begin
      RepointFunction(@MyTextOutA, @OldTextOutA);
   end;
   if @OldTextOutW <> nil then
   begin
      RepointFunction(@MyTextOutW, @OldTextOutW);
   end;
   if @OldTextOut <> nil then
   begin
      RepointFunction(@MyTextOut, @OldTextOut);
   end;
   if @OldDrawTextA <> nil then
   begin
      RepointFunction(@MyDrawTextA, @OldDrawTextA);
   end;
   if @OldDrawTextW <> nil then
   begin
      RepointFunction(@MyDrawTextW, @OldDrawTextW);
   end;
   if @OldDrawText <> nil then
   begin
      RepointFunction(@MyDrawText, @OldDrawText);
   end;

end;

exports API_Hookup, API_HookDown;
begin
end.