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dix: add selection filtering hooks 

Add hooks for filtering and fully rewrite rewrite selection requests
and events (what existing XACE hooks cannot do), e.g. for supporting
separate selection name spaces.

The hook can change individual fields in the parameter struct, so
operation continues with these changed values (eg. replace the original
selection name atom by a different one). It's also possible to stop
operations completely (with given result code) - in that case the
hook needs to take care of the remaining work to do (eg. sending events)

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
This commit is contained in:
Enrico Weigelt, metux IT consult 2025-03-17 18:26:21 +01:00
parent 824a78e8fc
commit 8a3401c94c
3 changed files with 205 additions and 51 deletions
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176
dix/selection.c
View File

@ -47,11 +47,11 @@ SOFTWARE.
#include <dix-config.h>
#include "dix/dix_priv.h"
#include "dix/selection_priv.h"
#include "windowstr.h"
#include "dixstruct.h"
#include "dispatch.h"
#include "selection.h"
#include "xace.h"
/*****************************************************************
@ -66,6 +66,7 @@ SOFTWARE.
Selection *CurrentSelections;
CallbackListPtr SelectionCallback;
CallbackListPtr SelectionFilterCallback = NULL;
int
dixLookupSelection(Selection ** result, Atom selectionName,
@ -171,12 +172,27 @@ ProcSetSelectionOwner(ClientPtr client)
if (CompareTimeStamps(time, currentTime) == LATER)
return Success;
if (stuff->window != None) {
rc = dixLookupWindow(&pWin, stuff->window, client, DixSetAttrAccess);
/* allow extensions to intercept */
SelectionFilterParamRec param = {
.client = client,
.selection = stuff->selection,
.owner = stuff->window,
.op = SELECTION_FILTER_SETOWNER,
};
CallCallbacks(&SelectionFilterCallback, &param);
if (param.skip) {
if (param.status != Success)
client->errorValue = stuff->selection;
return param.status;
}
if (param.owner != None) {
rc = dixLookupWindow(&pWin, param.owner, client, DixSetAttrAccess);
if (rc != Success)
return rc;
}
if (!ValidAtom(stuff->selection)) {
if (!ValidAtom(param.selection)) {
client->errorValue = stuff->selection;
return BadAtom;
}
@ -184,10 +200,11 @@ ProcSetSelectionOwner(ClientPtr client)
/*
* First, see if the selection is already set...
*/
rc = dixLookupSelection(&pSel, stuff->selection, client, DixSetAttrAccess);
if (rc != Success)
rc = dixLookupSelection(&pSel, param.selection, client, DixSetAttrAccess);
if (rc != Success) {
client->errorValue = stuff->selection;
return rc;
}
/* If the timestamp in client's request is in the past relative
to the time stamp indicating the last time the owner of the
@ -196,17 +213,27 @@ ProcSetSelectionOwner(ClientPtr client)
if (CompareTimeStamps(time, pSel->lastTimeChanged) == EARLIER)
return Success;
if (pSel->client && (!pWin || (pSel->client != client))) {
xEvent event = {
.u.selectionClear.time = time.milliseconds,
.u.selectionClear.window = pSel->window,
.u.selectionClear.atom = pSel->selection
SelectionFilterParamRec eventParam = {
.client = client,
.recvClient = pSel->client,
.owner = pSel->window,
.selection = stuff->selection,
.op = SELECTION_FILTER_EV_CLEAR,
};
event.u.u.type = SelectionClear;
WriteEventsToClient(pSel->client, 1, &event);
CallCallbacks(&SelectionFilterCallback, &eventParam);
if (!param.skip) {
xEvent event = {
.u.selectionClear.time = time.milliseconds,
.u.selectionClear.window = eventParam.owner,
.u.selectionClear.atom = eventParam.selection,
};
event.u.u.type = SelectionClear;
WriteEventsToClient(eventParam.recvClient, 1, &event);
}
}
pSel->lastTimeChanged = time;
pSel->window = stuff->window;
pSel->window = param.owner;
pSel->pWin = pWin;
pSel->client = (pWin ? client : NullClient);
@ -217,16 +244,26 @@ ProcSetSelectionOwner(ClientPtr client)
int
ProcGetSelectionOwner(ClientPtr client)
{
int rc;
Selection *pSel;
xGetSelectionOwnerReply reply;
REQUEST(xResourceReq);
REQUEST_SIZE_MATCH(xResourceReq);
if (!ValidAtom(stuff->id)) {
client->errorValue = stuff->id;
return BadAtom;
/* allow extensions to intercept */
SelectionFilterParamRec param = {
.client = client,
.selection = stuff->id,
.op = SELECTION_FILTER_GETOWNER,
};
CallCallbacks(&SelectionFilterCallback, &param);
if (param.skip) {
goto out;
}
if (!ValidAtom(param.selection)) {
param.status = BadAtom;
goto out;
}
reply = (xGetSelectionOwnerReply) {
@ -235,16 +272,21 @@ ProcGetSelectionOwner(ClientPtr client)
.length = 0,
};
rc = dixLookupSelection(&pSel, stuff->id, client, DixGetAttrAccess);
if (rc == Success)
param.status = dixLookupSelection(&pSel, param.selection, param.client, DixGetAttrAccess);
if (param.status == Success)
reply.owner = pSel->window;
else if (rc == BadMatch)
else if (param.status == BadMatch)
reply.owner = None;
else
return rc;
goto out;
WriteReplyToClient(client, sizeof(xGetSelectionOwnerReply), &reply);
return Success;
out:
if (param.status != Success)
client->errorValue = stuff->id;
return param.status;
}
int
@ -259,12 +301,29 @@ ProcConvertSelection(ClientPtr client)
REQUEST(xConvertSelectionReq);
REQUEST_SIZE_MATCH(xConvertSelectionReq);
rc = dixLookupWindow(&pWin, stuff->requestor, client, DixSetAttrAccess);
/* allow extensions to intercept */
SelectionFilterParamRec param = {
.client = client,
.selection = stuff->selection,
.op = SELECTION_FILTER_CONVERT,
.requestor = stuff->requestor,
.property = stuff->property,
.target = stuff->target,
.time = stuff->time,
};
CallCallbacks(&SelectionFilterCallback, &param);
if (param.skip) {
if (param.status != Success)
client->errorValue = stuff->selection;
return param.status;
}
rc = dixLookupWindow(&pWin, param.requestor, client, DixSetAttrAccess);
if (rc != Success)
return rc;
paramsOkay = ValidAtom(stuff->selection) && ValidAtom(stuff->target);
paramsOkay &= (stuff->property == None) || ValidAtom(stuff->property);
paramsOkay = ValidAtom(param.selection) && ValidAtom(param.target);
paramsOkay &= (param.property == None) || ValidAtom(param.property);
if (!paramsOkay) {
client->errorValue = stuff->property;
return BadAtom;
@ -273,32 +332,63 @@ ProcConvertSelection(ClientPtr client)
if (stuff->time == CurrentTime)
UpdateCurrentTime();
rc = dixLookupSelection(&pSel, stuff->selection, client, DixReadAccess);
rc = dixLookupSelection(&pSel, param.selection, client, DixReadAccess);
memset(&event, 0, sizeof(xEvent));
if (rc != Success && rc != BadMatch)
return rc;
else if (rc == Success && pSel->window != None) {
event.u.u.type = SelectionRequest;
event.u.selectionRequest.owner = pSel->window;
event.u.selectionRequest.time = stuff->time;
event.u.selectionRequest.requestor = stuff->requestor;
event.u.selectionRequest.selection = stuff->selection;
event.u.selectionRequest.target = stuff->target;
event.u.selectionRequest.property = stuff->property;
if (pSel->client && pSel->client != serverClient &&
!pSel->client->clientGone) {
WriteEventsToClient(pSel->client, 1, &event);
return Success;
/* If the specified selection has an owner, the X server sends
SelectionRequest event to that owner */
if (rc == Success && pSel->window != None && pSel->client &&
pSel->client != serverClient && !pSel->client->clientGone)
{
SelectionFilterParamRec evParam = {
.client = client,
.selection = stuff->selection,
.op = SELECTION_FILTER_EV_REQUEST,
.owner = pSel->window,
.requestor = stuff->requestor,
.property = stuff->property,
.target = stuff->target,
.time = stuff->time,
.recvClient = pSel->client,
};
CallCallbacks(&SelectionFilterCallback, &evParam);
if (evParam.skip) {
if (evParam.status != Success)
client->errorValue = stuff->selection;
return evParam.status;
}
event.u.u.type = SelectionRequest;
event.u.selectionRequest.owner = evParam.owner;
event.u.selectionRequest.time = evParam.time;
event.u.selectionRequest.requestor = evParam.requestor;
event.u.selectionRequest.selection = evParam.selection;
event.u.selectionRequest.target = evParam.target;
event.u.selectionRequest.property = evParam.property;
WriteEventsToClient(evParam.recvClient, 1, &event);
return Success;
}
/* If no owner for the specified selection exists, the X server generates
a SelectionNotify event to the requestor with property None. */
param.property = None;
CallCallbacks(&SelectionFilterCallback, &param);
if (param.skip) {
if (param.status != Success)
client->errorValue = stuff->selection;
return param.status;
}
event.u.u.type = SelectionNotify;
event.u.selectionNotify.time = stuff->time;
event.u.selectionNotify.requestor = stuff->requestor;
event.u.selectionNotify.selection = stuff->selection;
event.u.selectionNotify.target = stuff->target;
event.u.selectionNotify.property = None;
event.u.selectionNotify.time = param.time;
event.u.selectionNotify.requestor = param.requestor;
event.u.selectionNotify.selection = param.selection;
event.u.selectionNotify.target = param.target;
event.u.selectionNotify.property = param.property;
WriteEventsToClient(client, 1, &event);
return Success;
}

37
dix/selection_priv.h Normal file
View File

@ -0,0 +1,37 @@
/* SPDX-License-Identifier: MIT OR X11
*
* Copyright © 2024 Enrico Weigelt, metux IT consult <info@metux.net>
*/
#ifndef _XSERVER_DIX_SELECTION_PRIV_H
#define _XSERVER_DIX_SELECTION_PRIV_H
#include <X11/Xdefs.h>
#include <X11/Xproto.h>
#include "include/selection.h"
#define SELECTION_FILTER_GETOWNER 1
#define SELECTION_FILTER_SETOWNER 2
#define SELECTION_FILTER_CONVERT 3
#define SELECTION_FILTER_LISTEN 4
#define SELECTION_FILTER_EV_REQUEST 5
#define SELECTION_FILTER_EV_CLEAR 6
#define SELECTION_FILTER_NOTIFY 7
typedef struct {
int op;
Bool skip;
int status;
Atom selection;
ClientPtr client; // initiating client
ClientPtr recvClient; // client receiving event
Time time; // request time stamp
Window requestor;
Window owner;
Atom property;
Atom target;
} SelectionFilterParamRec, *SelectionFilterParamPtr;
extern CallbackListPtr SelectionFilterCallback;
#endif /* _XSERVER_DIX_SELECTION_PRIV_H */

43
xfixes/select.c
View File

@ -23,6 +23,7 @@
#include <dix-config.h>
#include "dix/dix_priv.h"
#include "dix/selection_priv.h"
#include "xfixesint.h"
#include "xace.h"
@ -78,13 +79,25 @@ XFixesSelectionCallback(CallbackListPtr *callbacks, void *data, void *args)
UpdateCurrentTimeIf();
for (e = selectionEvents; e; e = e->next) {
if (e->selection == selection && (e->eventMask & eventMask)) {
/* allow extensions to intercept */
SelectionFilterParamRec param = {
.client = e->pClient,
.selection = selection->selection,
.owner = (subtype == XFixesSetSelectionOwnerNotify) ?
selection->window : 0,
.op = SELECTION_FILTER_NOTIFY,
};
CallCallbacks(&SelectionFilterCallback, &param);
if (param.skip)
continue;
xXFixesSelectionNotifyEvent ev = {
.type = XFixesEventBase + XFixesSelectionNotify,
.subtype = subtype,
.window = e->pWindow->drawable.id,
.owner = (subtype == XFixesSetSelectionOwnerNotify) ?
selection->window : 0,
.selection = e->selection->selection,
.owner = param.owner,
.selection = param.selection,
.timestamp = currentTime.milliseconds,
.selectionTimestamp = selection->lastTimeChanged.milliseconds
};
@ -122,8 +135,22 @@ ProcXFixesSelectSelectionInput(ClientPtr client)
REQUEST(xXFixesSelectSelectionInputReq);
REQUEST_SIZE_MATCH(xXFixesSelectSelectionInputReq);
/* allow extensions to intercept */
SelectionFilterParamRec param = {
.client = client,
.selection = stuff->selection,
.owner = stuff->window,
.op = SELECTION_FILTER_LISTEN,
};
CallCallbacks(&SelectionFilterCallback, &param);
if (param.skip) {
if (param.status != Success)
client->errorValue = param.selection;
return param.status;
}
WindowPtr pWindow;
int rc = dixLookupWindow(&pWindow, stuff->window, client, DixGetAttrAccess);
int rc = dixLookupWindow(&pWindow, param.owner, param.client, DixGetAttrAccess);
if (rc != Success)
return rc;
if (stuff->eventMask & ~SelectionAllEvents) {
@ -135,13 +162,13 @@ ProcXFixesSelectSelectionInput(ClientPtr client)
SelectionEventPtr *prev, e;
Selection *selection;
rc = dixLookupSelection(&selection, stuff->selection, client, DixGetAttrAccess);
rc = dixLookupSelection(&selection, param.selection, param.client, DixGetAttrAccess);
if (rc != Success)
return rc;
for (prev = &selectionEvents; (e = *prev); prev = &e->next) {
if (e->selection == selection &&
e->pClient == client && e->pWindow == pWindow) {
e->pClient == param.client && e->pWindow == pWindow) {
break;
}
}
@ -158,9 +185,9 @@ ProcXFixesSelectSelectionInput(ClientPtr client)
e->next = 0;
e->selection = selection;
e->pClient = client;
e->pClient = param.client;
e->pWindow = pWindow;
e->clientResource = FakeClientID(client->index);
e->clientResource = FakeClientID(param.client->index);
/*
* Add a resource hanging from the window to