Xi, dix: Only one client at a time can change the pointer-keyboard pairing,

using xRegisterPairingClient request.

Xi/Makefile.am

@@ -62,6 +62,8 @@ libXi_la_SOURCES =	\
 	querydp.h \
 	queryst.c \
 	queryst.h \
+	regpair.c \
+	regpair.h \
 	selectev.c \
 	selectev.h \
 	sendexev.c \

Xi/chpkpair.c

@@ -73,10 +73,13 @@ int
 ProcXChangePointerKeyboardPairing(register ClientPtr client)
 {
     DeviceIntPtr pPointer, pKeyboard;
+    int ret;
 
     REQUEST(xChangePointerKeyboardPairingReq);
     REQUEST_SIZE_MATCH(xChangePointerKeyboardPairingReq);
 
+    /* check if client is registered */
+
     pPointer = LookupDeviceIntRec(stuff->pointer);
     if (pPointer == NULL)
     {
@@ -93,7 +96,14 @@ ProcXChangePointerKeyboardPairing(register ClientPtr client)
         return Success;
     }
 
-    pKeyboard->pSprite = pPointer->pSprite;
+    ret = PairDevices(client, pPointer, pKeyboard);
+    if (ret != Success)
+    {
+        SendErrorToClient(client, IReqCode, X_ChangePointerKeyboardPairing,
+                0, ret);
+        return Success;
+    }
+
 
     /* TODO: generate event here... */
     return Success;

Xi/extinit.c

@@ -102,6 +102,7 @@ SOFTWARE.
 #include "opendev.h"
 #include "querydp.h"
 #include "queryst.h"
+#include "regpair.h"
 #include "selectev.h"
 #include "sendexev.h"
 #include "chgkmap.h"
@@ -355,6 +356,8 @@ ProcIDispatch(register ClientPtr client)
         return (ProcXChangeDeviceCursor(client));
     else if (stuff->data == X_ChangePointerKeyboardPairing)
         return (ProcXChangePointerKeyboardPairing(client));
+    else if (stuff->data == X_RegisterPairingClient)
+        return (ProcXRegisterPairingClient(client));
     else {
 	SendErrorToClient(client, IReqCode, stuff->data, 0, BadRequest);
     }
@@ -452,6 +455,8 @@ SProcIDispatch(register ClientPtr client)
         return (SProcXChangeDeviceCursor(client));
     else if (stuff->data == X_ChangePointerKeyboardPairing)
         return (SProcXChangePointerKeyboardPairing(client));
+    else if (stuff->data == X_RegisterPairingClient)
+        return (SProcXRegisterPairingClient(client));
     else {
 	SendErrorToClient(client, IReqCode, stuff->data, 0, BadRequest);
     }
@@ -527,6 +532,9 @@ SReplyIDispatch(ClientPtr client, int len, xGrabDeviceReply * rep)
     else if (rep->RepType == X_QueryDevicePointer)
 	SRepXQueryDevicePointer(client, len,
 				 (xQueryDevicePointerReply *) rep);
+    else if (rep->RepType == X_RegisterPairingClient)
+	SRepXRegisterPairingClient(client, len,
+				 (xRegisterPairingClientReply *) rep);
     else {
 	FatalError("XINPUT confused sending swapped reply");
     }

Xi/regpair.c

@@ -0,0 +1,108 @@
+/*
+
+Copyright 2007 Peter Hutterer <peter@cs.unisa.edu.au>
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of the author shall
+not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization
+from the author.
+
+*/
+
+/***********************************************************************
+ *
+ * Request to authenticate as pairing client
+ *
+ */
+
+#define	 NEED_EVENTS
+#define	 NEED_REPLIES
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include <X11/X.h>	/* for inputstr.h    */
+#include <X11/Xproto.h>	/* Request macro     */
+#include "inputstr.h"	/* DeviceIntPtr      */
+#include "windowstr.h"	/* window structure  */
+#include <X11/extensions/XI.h>
+#include <X11/extensions/XIproto.h>
+#include "extnsionst.h"
+#include "exevents.h"
+#include "exglobals.h"
+
+#include "regpair.h"
+
+/***********************************************************************
+ *
+ * This procedure allows a client to register the pairing of a pointer 
+ * with a keyboard.
+ *
+ */
+
+int 
+SProcXRegisterPairingClient(ClientPtr client)
+{
+    char n;
+    REQUEST(xRegisterPairingClientReq);
+    swaps(&stuff->length, n);
+    return ProcXRegisterPairingClient(client);
+}
+
+int 
+ProcXRegisterPairingClient(ClientPtr client)
+{
+    xRegisterPairingClientReply rep;
+
+    REQUEST(xRegisterPairingClientReq);
+    REQUEST_SIZE_MATCH(xRegisterPairingClientReq);
+
+    if (stuff->disable)
+        UnregisterPairingClient(client);
+
+    rep.repType = X_Reply;
+    rep.RepType = X_RegisterPairingClient;
+    rep.length = 0;
+    rep.sequenceNumber = client->sequence;
+    rep.success = stuff->disable || RegisterPairingClient(client);
+
+    WriteReplyToClient(client, sizeof(xRegisterPairingClientReply), &rep);
+    return Success;
+}
+
+/***********************************************************************
+ *
+ * This procedure writes the reply for the XRegisterPairingClient function,
+ * if the client and server have a different byte ordering.
+ *
+ */
+
+void
+SRepXRegisterPairingClient(ClientPtr client, int size, 
+        xRegisterPairingClientReply* rep)
+{
+    register char n;
+
+    swaps(&rep->sequenceNumber, n);
+    swapl(&rep->length, n);
+    WriteToClient(client, size, (char *)rep);
+}
+

Xi/regpair.h

@@ -0,0 +1,43 @@
+/*
+
+Copyright 2007 Peter Hutterer <peter@cs.unisa.edu.au>
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of the author shall
+not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization
+from the author.
+
+*/
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#ifndef REGPAIR_H
+#define REGPAIR_H 1
+
+int SProcXRegisterPairingClient(ClientPtr /* client */);
+int ProcXRegisterPairingClient(ClientPtr /* client */);
+
+void SRepXRegisterPairingClient(ClientPtr /* client */, 
+                                int /* size */,
+                                xRegisterPairingClientReply* /* rep */);
+
+#endif /* REGPAIR_H */

dix/devices.c

@@ -81,6 +81,9 @@ SOFTWARE.
 
 int CoreDevicePrivatesIndex = 0, CoreDevicePrivatesGeneration = -1;
 
+/* The client that is allowed to change pointer-keyboard pairings. */
+static ClientPtr pairingClient = NULL;
+
 DeviceIntPtr
 AddInputDevice(DeviceProc deviceProc, Bool autoStart)
 {
@@ -1926,5 +1929,54 @@ ProcQueryKeymap(ClientPtr client)
 	bzero((char *)&rep.map[0], 32);
 
     WriteReplyToClient(client, sizeof(xQueryKeymapReply), &rep);
+ 
+   return Success;
+}
+
+/* Pair the keyboard to the pointer device. Keyboard events will follow the
+ * pointer sprite. 
+ */
+int 
+PairDevices(ClientPtr client, DeviceIntPtr pointer, DeviceIntPtr keyboard)
+{
+    if (!pairingClient)
+        RegisterPairingClient(client);
+    else if (pairingClient != client)
+        return BadAccess;
+
+    keyboard->pSprite = pointer->pSprite;
     return Success;
 }
+
+/*
+ * Register a client to be able to pair devices. 
+ */
+Bool
+RegisterPairingClient(ClientPtr client)
+{
+    if (!pairingClient)
+    {
+        pairingClient = client;
+    } else if (pairingClient != client)
+    {
+        return False;
+    }
+    return True;
+}
+
+/*
+ * Unregister pairing client;
+ */
+Bool 
+UnregisterPairingClient(ClientPtr client)
+{
+    if (pairingClient) 
+    {
+        if ( pairingClient == client)
+        {
+            pairingClient = NULL;
+        } else 
+            return False;
+    }
+    return True;
+}

dix/dispatch.c

@@ -3568,6 +3568,7 @@ CloseDownClient(register ClientPtr client)
 	DeleteClientFromAnySelections(client);
 	ReleaseActiveGrabs(client);
 	DeleteClientFontStuff(client);
+        UnregisterPairingClient(client); /* other clients can pair devices */
 	if (!really_close_down)
 	{
 	    /*  This frees resources that should never be retained

include/input.h

@@ -454,4 +454,11 @@ extern void DDXRingBell(
     int pitch,
     int duration);
 
+extern int PairDevices(ClientPtr client, 
+                       DeviceIntPtr pointer, 
+                       DeviceIntPtr keyboard);
+
+extern Bool RegisterPairingClient(ClientPtr client);
+extern Bool UnregisterPairingClient(ClientPtr client);
+
 #endif /* INPUT_H */