_UNDOCUMENTED CORNER_
edited by Andrew Schulman

"Spying on WinHelp"
by Ron Burk


[LISTING ONE]

/* helpspy.c - spy on WM_WINHELP messages, system-wide */

#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include "hookmsg.h"
#include "helpspy.h"

#define MAX_STRING      (256)


LRESULT CALLBACK _export HookProc(int, WPARAM, LPARAM);
BOOL CALLBACK _export DlgProc(HWND, UINT, WPARAM, LPARAM);

UINT        WM_WINHELP; /* a registered window message */
UINT        WM_WINDOC;  /* the one that Viewer uses    */
HWND        ListBox;    /* listbox to display messages */
HICON       MyIcon;

typedef struct  HelpParams {
    int     Size;
    int     Message;
    long    Context;
    long    Unknown;
    int     PathOffset;
    int     StringOffset;
    char    Path[1];
    }           HelpParams;
static  HHOOK   MsgHook;
#ifdef __BORLANDC__
    #pragma argsused
#endif
int PASCAL WinMain(HINSTANCE Me, HINSTANCE Previous,
             LPSTR lpszCmdLine, int nCmdShow)    {
    if(Previous) {
        MessageBox(NULL, "HelpSpy already running.", "HelpSpy", MB_OK);
        return 0;
        }
    MyIcon      = LoadIcon(Me, "HelpSpyIcon");
    WM_WINHELP  = RegisterWindowMessage("WM_WINHELP");
    WM_WINDOC   = RegisterWindowMessage("WM_WINDOC");
    MsgHook     = SetWindowsHookEx(WH_CALLWNDPROC, HookProc, Me, NULL);
    DialogBox(Me, "HelpSpyDialog", NULL, DlgProc);
    UnhookWindowsHookEx(MsgHook);
    return 0;
    }
/* HookProc - pass only WM_WINHELP messages to DumpWinHelp(). */
LRESULT CALLBACK _export HookProc(int Code, WPARAM Param1, LPARAM Param2) {
    void    DumpWinHelp(UINT Message, LPARAM Param2);
    typedef struct HMSG {
        LPARAM  lParam;
        WPARAM  wParam;
        UINT    message;
        HWND    hwnd;
        }   HMSG;
    HMSG *Message = (HMSG *)Param2;
    if(Message->message == WM_WINHELP || Message->message == WM_WINDOC)
        DumpWinHelp(Message->message, Message->lParam);
    if(Code < 0)

        CallNextHookEx(MsgHook, Code, Param1, Param2);
    return 0;
    }
/* DumpWinHelp() - dump a WM_WINHELP message. */
void    DumpWinHelp(UINT Message, LPARAM Param2) {
    char        String[MAX_STRING];
    char       *Command = "HELP_UNKNOWN";
    HGLOBAL     Handle  = (HGLOBAL)Param2;
    HelpParams  *Params = (HelpParams *)GlobalLock(Handle);
    switch(Params->Message) {
        case HELP_CONTEXT:      Command = "HELP_CONTEXT";       break;
        case HELP_CONTEXTPOPUP: Command = "HELP_CONTEXTPOPUP";  break;
        case HELP_CONTENTS:     Command = "HELP_CONTENTS";      break;
        case HELP_SETCONTENTS:  Command = "HELP_SETCONTENTS";   break;
        case HELP_KEY:          Command = "HELP_KEY";           break;
        case HELP_PARTIALKEY:   Command = "HELP_PARTIALKEY";    break;
        case HELP_MULTIKEY:     Command = "HELP_MULTIKEY";      break;
        case HELP_COMMAND:      Command = "HELP_COMMAND";       break;
        case HELP_SETWINPOS:    Command = "HELP_SETWINPOS";     break;
        case HELP_FORCEFILE:    Command = "HELP_FORCEFILE";     break;
        case HELP_HELPONHELP:   Command = "HELP_HELPONHELP";    break;
        case HELP_QUIT:         Command = "HELP_QUIT";          break;
        }
    sprintf(String, "%s(%s", (Message == WM_WINHELP)
        ? "WinHelp" : "MVAPI", Command);
    switch(Params->Message) {
        case    HELP_SETCONTENTS    :
        case    HELP_CONTEXT        :
        case    HELP_CONTEXTPOPUP   :
            sprintf(String+strlen(String), ",%ld)", Params->Context);
            break;
        case    HELP_KEY            :
        case    HELP_PARTIALKEY     :
        case    HELP_COMMAND        :
            sprintf(String+strlen(String), ",'%s')",
                    (char *)Params + Params->StringOffset);
            break;
        case    HELP_CONTENTS       :
        case    HELP_FORCEFILE      :
        case    HELP_HELPONHELP     :
        case    HELP_QUIT           :
            strcat(String, ")");
            break;
        case    HELP_SETWINPOS      :   {
            HELPWININFO *Info = (HELPWININFO *)
                    ((char *)Params + Params->StringOffset);
            sprintf(String+strlen(String),
                   ",x=%d,y=%d,dx=%d,dy=%d,wMax=%d,\"%s\")",
                       Info->x, Info->y, Info->dx, Info->dy,
                              Info->wMax, Info->rgchMember);
            break;
            }
        case    HELP_MULTIKEY       :   {

          MULTIKEYHELP *MultiKey    = (MULTIKEYHELP *)
                    ((char *)Params + Params->StringOffset);
          sprintf(String+strlen(String), ",'%c', '%.*s')", MultiKey->mkKeylist,
            MultiKey->mkSize-sizeof(UINT)-sizeof(BYTE), MultiKey->szKeyphrase);
            break;
            }
        default :
            strcat(String, ")");
        }
    GlobalUnlock(Handle);
    SendMessage(ListBox, LB_INSERTSTRING, 0, (LPARAM)(LPCSTR)String);
    }
/* DlgProc() - Store listbox handle in global variable. */
#ifdef __BORLANDC__
    #pragma argsused
#endif
BOOL CALLBACK _export DlgProc(HWND Dialog, UINT Message,
                             WPARAM Param1, LPARAM Param2) {
    if(Message == WM_INITDIALOG) {
        ListBox     = GetDlgItem(Dialog, ID_LISTBOX);
        return TRUE;
        }
    else if(Message == WM_PAINT && IsIconic(Dialog))
        {
        PAINTSTRUCT PaintInfo;
        BeginPaint(Dialog, &PaintInfo);
        DrawIcon(PaintInfo.hdc, 0, 0, MyIcon);
        EndPaint(Dialog, &PaintInfo);
        }
    else if(Message == WM_COMMAND)
        if(Param1 == IDOK || Param1 == IDCANCEL) {
            EndDialog(Dialog, 0);
            return TRUE;
            }
    return FALSE;
    }




[LISTING TWO]

APP     =helpspy
OBJ     =$(APP).obj
MODEL   =-ml! 
#DEBUG   =-d
CCFLAGS =$(DEBUG) $(MODEL) -DSTRICT -wed

.rc.res :
    rc -r $*.rc

.c.obj :
    cc -c $(CCFLAGS) $*.c
$(APP).exe : $(OBJ) $(APP).res makefile
    cc $(DEBUG) $(MODEL) $(OBJ) $(APP).res
$(APP).res  $(APP).obj : $(APP).h



[LISTING THREE]

#include <windows.h>

#define ID_LISTBOX  101
#define MENU_HELP   201


[LISTING FOUR]

#include "helpspy.h"

HelpSpyDialog DIALOG 15, 131, 306, 41
STYLE WS_POPUP | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX
CAPTION "HelpSpy"
BEGIN
    CONTROL "", ID_LISTBOX, "LISTBOX", LBS_NOTIFY | LBS_DISABLENOSCROLL | 
        WS_CHILD | WS_VISIBLE | WS_VSCROLL, 2, 0, 304, 42

END
HelpSpyIcon ICON "helpspy.ico"