Fixed some lockups in XIM code when the application is running with multi thread support. These lockups occur deep down in XFilterEvents() which itself locks when another Xlib function gets called that also locks. This fixes two instances by separating those Xlib functions into an internal (non-locking) call and a locking wrapper that is used as an external function. There may be several other such instances therefore another more general patch is eventually required (Bugzilla #1182).

include/X11/Xlibint.h

@@ -1298,6 +1298,15 @@ extern void _XSetClipRectangles (
     int n,
     int ordering);
 
+Status _XGetWindowAttributes(
+    register Display *dpy,
+    Window w,
+    XWindowAttributes *attr);
+
+int _XPutBackEvent (
+    register Display *dpy, 
+    register XEvent *event);
+
 _XFUNCPROTOEND
 
 #endif /* _XLIBINT_H_ */

modules/im/ximcp/imDefLkup.c

@@ -463,7 +463,7 @@ _XimGetWindowEventmask(
     Xim			im = (Xim )ic->core.im;
     XWindowAttributes	atr;
 
-    if (!XGetWindowAttributes(im->core.display, ic->core.focus_window, &atr))
+    if (!_XGetWindowAttributes(im->core.display, ic->core.focus_window, &atr))
 	return 0;
     return (EVENTMASK)atr.your_event_mask;
 }

modules/im/ximcp/imLcFlt.c

@@ -73,7 +73,7 @@ _XimLocalFilter(d, w, ev, client_data)
 	    ic->private.local.composed = p;
 	    /* return back to client KeyPressEvent keycode == 0 */
 	    ev->xkey.keycode = 0;
-	    XPutBackEvent(d, ev);
+	    _XPutBackEvent(d, ev);
 	    /* initialize internal state for next key sequence */
 	    ic->private.local.context = ((Xim)ic->core.im)->private.local.top;
 	    return(True);

src/GetWAttrs.c

@@ -24,7 +24,6 @@ used in advertising or otherwise to promote the sale, use or other dealings
 in this Software without prior written authorization from The Open Group.
 
 */
-/* $XFree86$ */
 
 #define NEED_REPLIES
 #include "Xlibint.h"
@@ -84,10 +83,11 @@ _XWAttrsHandler(
     return True;
 }
 
-Status XGetWindowAttributes(dpy, w, attr)
-     register Display *dpy;
-     Window w;
-     XWindowAttributes *attr;
+Status
+_XGetWindowAttributes(
+    register Display *dpy,
+    Window w,
+    XWindowAttributes *attr)
 {       
     xGetGeometryReply rep;
     register xResourceReq *req;
@@ -96,7 +96,6 @@ Status XGetWindowAttributes(dpy, w, attr)
     _XAsyncHandler async;
     _XWAttrsState async_state;
  
-    LockDisplay(dpy);
     GetResReq(GetWindowAttributes, w, req);
 
     async_state.attr_seq = dpy->request;
@@ -113,14 +112,10 @@ Status XGetWindowAttributes(dpy, w, attr)
 
     if (!_XReply (dpy, (xReply *)&rep, 0, xTrue)) {
 	DeqAsyncHandler(dpy, &async);
-	UnlockDisplay(dpy);
-	SyncHandle();
 	return (0);
 	}
     DeqAsyncHandler(dpy, &async);
     if (!async_state.attr) {
-	UnlockDisplay(dpy);
-	SyncHandle();
 	return (0);
     }
     attr->x = cvtINT16toInt (rep.x);
@@ -138,8 +133,22 @@ Status XGetWindowAttributes(dpy, w, attr)
 	    break;
 	}
     }
-    UnlockDisplay(dpy);
-    SyncHandle();
     return(1);
 }
 
+Status
+XGetWindowAttributes(
+    Display *dpy,
+    Window w,
+    XWindowAttributes *attr)
+{
+    Status ret;
+
+    LockDisplay(dpy);
+    ret = _XGetWindowAttributes(dpy, w, attr);
+    UnlockDisplay(dpy);
+    SyncHandle();
+
+    return ret;
+}
+

src/PutBEvent.c

@@ -33,16 +33,14 @@ from The Open Group.
 #include "Xlibint.h"
 
 int
-XPutBackEvent (dpy, event)
-	register Display *dpy;
-	register XEvent *event;
+_XPutBackEvent (
+    register Display *dpy, 
+    register XEvent *event)
 	{
 	register _XQEvent *qelt;
 
-	LockDisplay(dpy);
 	if (!dpy->qfree) {
     	    if ((dpy->qfree = (_XQEvent *) Xmalloc (sizeof (_XQEvent))) == NULL) {
-		UnlockDisplay(dpy);
 		return 0;
 	    }
 	    dpy->qfree->next = NULL;
@@ -56,6 +54,18 @@ XPutBackEvent (dpy, event)
 	if (dpy->tail == NULL)
 	    dpy->tail = qelt;
 	dpy->qlen++;
-	UnlockDisplay(dpy);
 	return 0;
 	}
+
+int
+XPutBackEvent (
+    register Display * dpy, 
+    register XEvent *event)
+	{
+	int ret;
+
+	LockDisplay(dpy);
+	ret = _XPutBackEvent(dpy, event);
+	UnlockDisplay(dpy);
+	return ret;
+	}