Memory access error in XWin -multiwindow

[Harold L Hunt II]

Biju,

I can now reproduce your problem using both Test91 and Test91-DEBUG 
(with Ralf's patches applied).  I reproduce the problem using ssh to 
login to my home machine which is on an 256 Kbps uplink.  When I launch 
konqueror remotely, XWin.exe dies with the Windows error message.  I 
tried the same thing at home on the local network with no problems. 
Thus, we are most likely looking at a race condition.

I think that this problem probably doesn't have anything to do with 
malloc failing... rather, I think the problem is that we call 
XInitThreads (or whatever it is called) more than once in the same 
process.  I should add protection so that that function is only called 
once for the entire process.

I don't promise that this will fix the problem, but I at least have a 
test case now so I can start to do something about it.

Harold

Biju G C wrote:

> Harold,
> 
> I am facing an issue of Memory access error in XWin -multiwindow mode
> see http://www.cygwin.com/ml/cygwin-xfree/2003-06/msg00294.html
> 
> So Ralf pointed me to http://cygwin.com/ml/cygwin-xfree/2003-06/msg00162.html
> 
> After seeing that patch, I have just gone thru XWin Source and found,
> at lot of place we call memory alloc and not testing the return value.
> I am attaching the list & extracts from programs
> I dont know all of those will make any issue.
> 
> I did not checked whether it is properly "free()"-ed
> And also I did not checked the functions which receives 
> allocated memory another function as return value or thru 
> a passed argument to the called function.
> 
> 
> List of variables:-
> 
> in winmultiwindowwm.c
>        pXMsgArg        at function winInitWM 
> 
> 
> in winmultiwindowwindow.c
>        vlist           at function winMoveXWindow 
>        vlist           at function winResizeXWindow 
> 
> 
> in winmultiwindowicons.c
>        iconData        at function winScaleXBitmapToWindows 
>        image           at function winXIconToHICON 
>        imageMask       at function winXIconToHICON 
>        mask            at function winXIconToHICON 
> 
> 
> in winmultiwindowclass.c
>        *res_name       at function winMultiWindowGetClassHint 
>        *res_role       at function winMultiWindowGetWindowRole 
> 
> 
> in winconfig.c
>        ret             at function winNormalizeName 
> 
> 
> in winclipboardxevents.c
>        pszUTF8         at function winClipboardFlushXEvents 
>        pszReturnData   at function winClipboardFlushXEvents 
>        pwszUnicodeStr  at function winClipboardFlushXEvents 
>        hGlobal         at function winClipboardFlushXEvents 
> 
> 
> in winclipboardtextconv.c
>        pszDestBegin / pszDest at function winClipboardUNIXtoDOS 
> 
> 
> 
> 
> ####### EXTRACTS FROM PROGRAMS ##########
> 
> 
> 
> ####### NEXT FILE ##########
> 
> winmultiwindowwm.c
> 
> Bool
> winInitWM (void **ppWMInfo,
> 	   pthread_t *ptWMProc,
> 	   pthread_t *ptXMsgProc,
> 	   pthread_mutex_t *ppmServerStarted,
> 	   int dwScreen)
> {
>   WMProcArgPtr		pArg = (WMProcArgPtr) malloc (sizeof(WMProcArgRec));
>   WMInfoPtr		pWMInfo = (WMInfoPtr) malloc (sizeof(WMInfoRec));
>   XMsgProcArgPtr	pXMsgArg = (XMsgProcArgPtr) malloc (sizeof(XMsgProcArgRec));
> 
>   /* Bail if the input parameters are bad */
>   if (pArg == NULL || pWMInfo == NULL)
>     {
>       ErrorF ("winInitWM - malloc fail.\n");
>       return FALSE;
>     }
> 
> 
> 
> 
> ####### NEXT FILE ##########
> 
> winmultiwindowwindow.c
> 
> void
> winMoveXWindow (WindowPtr pWin, int x, int y)
> {
>   XID *vlist = malloc(sizeof(long)*2);
> 
>   (CARD32*)vlist[0] = x;
>   (CARD32*)vlist[1] = y;
>   ConfigureWindow (pWin, CWX | CWY, vlist, wClient(pWin));
>   free(vlist);
> }
> 
> 
> /*
>  * winResizeXWindow - 
>  */
> 
> void
> winResizeXWindow (WindowPtr pWin, int w, int h)
> {
>   XID *vlist = malloc(sizeof(long)*2);
> 
>   (CARD32*)vlist[0] = w;
>   (CARD32*)vlist[1] = h;
>   ConfigureWindow (pWin, CWWidth | CWHeight, vlist, wClient(pWin));
>   free(vlist);
> }
> 
> 
> 
> ####### NEXT FILE ##########
> 
> winmultiwindowicons.c
> 
> 
> static void
> winScaleXBitmapToWindows (int iconSize,
> 			  int effBPP,
> 			  PixmapPtr pixmap,
> 			  unsigned char *image)
> {
> 
> ........
> 
>   iconData = malloc (xStride * pixmap->drawable.height);
>   miGetImage ((DrawablePtr) &(pixmap->drawable), 0, 0,
> 	      pixmap->drawable.width, pixmap->drawable.height,
> 	      ZPixmap, 0xffffffff, iconData);
> 
> 
> 
> 
> 
> 
> HICON
> winXIconToHICON (WindowPtr pWin)
> {
> 
> .........
>   image = (unsigned char * ) malloc (stride * iconSize);
>   imageMask = (unsigned char *) malloc (stride * iconSize);
>   mask = (unsigned char *) malloc (maskStride * iconSize);
> 
> 
> 
> 
> 
> ####### NEXT FILE ##########
> 
> winmultiwindowclass.c
> 
> int
> winMultiWindowGetClassHint (WindowPtr pWin, char **res_name, char **res_class)
> {
> 
> ....
> 
> (*res_name) = malloc (len_name + 1);
> 
> 
> int
> winMultiWindowGetWindowRole (WindowPtr pWin, char **res_role)
> {
> 
> ....
> (*res_role) = malloc (len_role + 1);
> 
> 
> 
> 
> ####### NEXT FILE ##########
> 
> winconfig.c
> 
> char *
> winNormalizeName (const char *s)
> {
> 
> ......
> 
>   ret = malloc (strlen (s) + 1);
> 
> 
> 
> 
> ####### NEXT FILE ##########
> 
> winclipboardxevents.c
> Bool
> winClipboardFlushXEvents (HWND hwnd,
> 			  Atom atomClipboard,
> 			  Atom atomLocalProperty,
> 			  Atom atomUTF8String,
> 			  Atom atomCompoundText,
> 			  Atom atomTargets,
> 			  Atom atomDeleteWindow,
> 			  int iWindow,
> 			  Display *pDisplay,
> 			  Bool fUnicodeSupport)
> {
> 
> ........
> 	      pszUTF8 = (char *) malloc (iUTF8); /* Don't need +1 */
> 	      WideCharToMultiByte (CP_UTF8,
> 
> 
> 
> ...........
> 
> 
> 	      if (iCount > 0)
> 		{
> 		  pszReturnData = malloc (strlen (ppszTextList[0]) + 1);
> 		  strcpy (pszReturnData, ppszTextList[0]);
> 		}
> 	      else
> 		{
> 		  pszReturnData = malloc (1);
> 		  pszReturnData[0] = 0;
> 		}
> 
> 
> ...........
> 	      pwszUnicodeStr
> 		= (wchar_t*) malloc (sizeof (wchar_t) * (iUnicodeLen + 1));
> 	      
> 	      /* Do the actual conversion */
> 	      MultiByteToWideChar (CP_UTF8,
> 				   0,
> 				   pszReturnData,
> 				   -1,
> 				   pwszUnicodeStr,
> 				   iUnicodeLen);
> 
> ........
> 
> 	  /* Allocate global memory for the X clipboard data */
> 	  if (fUnicodeSupport)
> 	    hGlobal = GlobalAlloc (GMEM_MOVEABLE,
> 				   sizeof (wchar_t) * (iUnicodeLen + 1));
> 	  else
> 	    hGlobal = GlobalAlloc (GMEM_MOVEABLE, strlen (pszReturnData) + 1);
> 
> 	  /* Obtain a pointer to the global memory */
> 	  pszGlobalData = GlobalLock (hGlobal);
> 	  if (pszGlobalData == NULL)
> 	    {
> ........
> 
> 
> 
> 
> ####### NEXT FILE ##########
> 
> winclipboardtextconv.c
> 
> void
> winClipboardUNIXtoDOS (unsigned char **ppszData, int iLength)
> {
> 
> .......
>   /* Allocate a new string */
>   pszDestBegin = pszDest = malloc (iLength + iNewlineCount + 1);
> 
> 
> 
> 
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