summaryrefslogtreecommitdiff
path: root/xserver/dix/grabs.c
blob: 2a307a2b9037b3adf8286c2decfa26a4cbc3b372 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
/*

Copyright 1987, 1998  The Open Group

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 OPEN GROUP 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 Open Group 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 Open Group.

Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts,

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN action OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

*/

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <X11/X.h>
#include "misc.h"
#include <X11/Xproto.h>
#include <X11/extensions/XI2.h>
#include "windowstr.h"
#include "inputstr.h"
#include "cursorstr.h"
#include "dixgrabs.h"
#include "xace.h"
#include "exevents.h"
#include "exglobals.h"
#include "inpututils.h"
#include "client.h"

#define BITMASK(i) (((Mask)1) << ((i) & 31))
#define MASKIDX(i) ((i) >> 5)
#define MASKWORD(buf, i) buf[MASKIDX(i)]
#define BITSET(buf, i) MASKWORD(buf, i) |= BITMASK(i)
#define BITCLEAR(buf, i) MASKWORD(buf, i) &= ~BITMASK(i)
#define GETBIT(buf, i) (MASKWORD(buf, i) & BITMASK(i))

void
PrintDeviceGrabInfo(DeviceIntPtr dev)
{
    ClientPtr client;
    LocalClientCredRec *lcc;
    int i, j;
    GrabInfoPtr devGrab = &dev->deviceGrab;
    GrabPtr grab = devGrab->grab;
    Bool clientIdPrinted = FALSE;

    ErrorF("Active grab 0x%lx (%s) on device '%s' (%d):\n",
           (unsigned long) grab->resource,
           (grab->grabtype == XI2) ? "xi2" :
           ((grab->grabtype == CORE) ? "core" : "xi1"), dev->name, dev->id);

    client = clients[CLIENT_ID(grab->resource)];
    if (client) {
        pid_t clientpid = GetClientPid(client);
        const char *cmdname = GetClientCmdName(client);
        const char *cmdargs = GetClientCmdArgs(client);

        if ((clientpid > 0) && (cmdname != NULL)) {
            ErrorF("      client pid %ld %s %s\n",
                   (long) clientpid, cmdname, cmdargs ? cmdargs : "");
            clientIdPrinted = TRUE;
        }
        else if (GetLocalClientCreds(client, &lcc) != -1) {
            ErrorF("      client pid %ld uid %ld gid %ld\n",
                   (lcc->fieldsSet & LCC_PID_SET) ? (long) lcc->pid : 0,
                   (lcc->fieldsSet & LCC_UID_SET) ? (long) lcc->euid : 0,
                   (lcc->fieldsSet & LCC_GID_SET) ? (long) lcc->egid : 0);
            FreeLocalClientCreds(lcc);
            clientIdPrinted = TRUE;
        }
    }
    if (!clientIdPrinted) {
        ErrorF("      (no client information available for client %d)\n",
               CLIENT_ID(grab->resource));
    }

    /* XXX is this even correct? */
    if (devGrab->sync.other)
        ErrorF("      grab ID 0x%lx from paired device\n",
               (unsigned long) devGrab->sync.other->resource);

    ErrorF("      at %ld (from %s grab)%s (device %s, state %d)\n",
           (unsigned long) devGrab->grabTime.milliseconds,
           devGrab->fromPassiveGrab ? "passive" : "active",
           devGrab->implicitGrab ? " (implicit)" : "",
           devGrab->sync.frozen ? "frozen" : "thawed", devGrab->sync.state);

    if (grab->grabtype == CORE) {
        ErrorF("        core event mask 0x%lx\n",
               (unsigned long) grab->eventMask);
    }
    else if (grab->grabtype == XI) {
        ErrorF("      xi1 event mask 0x%lx\n",
               devGrab->implicitGrab ? (unsigned long) grab->deviceMask :
               (unsigned long) grab->eventMask);
    }
    else if (grab->grabtype == XI2) {
        for (i = 0; i < xi2mask_num_masks(grab->xi2mask); i++) {
            const unsigned char *mask;
            int print;

            print = 0;
            for (j = 0; j < XI2MASKSIZE; j++) {
                mask = xi2mask_get_one_mask(grab->xi2mask, i);
                if (mask[j]) {
                    print = 1;
                    break;
                }
            }
            if (!print)
                continue;
            ErrorF("      xi2 event mask for device %d: 0x", dev->id);
            for (j = 0; j < xi2mask_mask_size(grab->xi2mask); j++)
                ErrorF("%x", mask[j]);
            ErrorF("\n");
        }
    }

    if (devGrab->fromPassiveGrab) {
        ErrorF("      passive grab type %d, detail 0x%x, "
               "activating key %d\n", grab->type, grab->detail.exact,
               devGrab->activatingKey);
    }

    ErrorF("      owner-events %s, kb %d ptr %d, confine %lx, cursor 0x%lx\n",
           grab->ownerEvents ? "true" : "false",
           grab->keyboardMode, grab->pointerMode,
           grab->confineTo ? (unsigned long) grab->confineTo->drawable.id : 0,
           grab->cursor ? (unsigned long) grab->cursor->id : 0);
}

void
UngrabAllDevices(Bool kill_client)
{
    DeviceIntPtr dev;
    ClientPtr client;

    ErrorF("Ungrabbing all devices%s; grabs listed below:\n",
           kill_client ? " and killing their owners" : "");

    for (dev = inputInfo.devices; dev; dev = dev->next) {
        if (!dev->deviceGrab.grab)
            continue;
        PrintDeviceGrabInfo(dev);
        client = clients[CLIENT_ID(dev->deviceGrab.grab->resource)];
        if (!kill_client || !client || client->clientGone)
            dev->deviceGrab.DeactivateGrab(dev);
        if (kill_client)
            CloseDownClient(client);
    }

    ErrorF("End list of ungrabbed devices\n");
}

GrabPtr
AllocGrab(const GrabPtr src)
{
    GrabPtr grab = calloc(1, sizeof(GrabRec));

    if (grab) {
        grab->xi2mask = xi2mask_new();
        if (!grab->xi2mask) {
            free(grab);
            grab = NULL;
        }
        else if (src && !CopyGrab(grab, src)) {
            free(grab->xi2mask);
            free(grab);
            grab = NULL;
        }
    }

    return grab;
}

GrabPtr
CreateGrab(int client, DeviceIntPtr device, DeviceIntPtr modDevice,
           WindowPtr window, enum InputLevel grabtype, GrabMask *mask,
           GrabParameters *param, int type,
           KeyCode keybut,        /* key or button */
           WindowPtr confineTo, CursorPtr cursor)
{
    GrabPtr grab;

    grab = AllocGrab(NULL);
    if (!grab)
        return (GrabPtr) NULL;
    grab->resource = FakeClientID(client);
    grab->device = device;
    grab->window = window;
    if (grabtype == CORE || grabtype == XI)
        grab->eventMask = mask->core;       /* same for XI */
    else
        grab->eventMask = 0;
    grab->deviceMask = 0;
    grab->ownerEvents = param->ownerEvents;
    grab->keyboardMode = param->this_device_mode;
    grab->pointerMode = param->other_devices_mode;
    grab->modifiersDetail.exact = param->modifiers;
    grab->modifiersDetail.pMask = NULL;
    grab->modifierDevice = modDevice;
    grab->type = type;
    grab->grabtype = grabtype;
    grab->detail.exact = keybut;
    grab->detail.pMask = NULL;
    grab->confineTo = confineTo;
    grab->cursor = RefCursor(cursor);
    grab->next = NULL;

    if (grabtype == XI2)
        xi2mask_merge(grab->xi2mask, mask->xi2mask);
    return grab;

}

void
FreeGrab(GrabPtr pGrab)
{
    BUG_RETURN(!pGrab);

    free(pGrab->modifiersDetail.pMask);
    free(pGrab->detail.pMask);

    if (pGrab->cursor)
        FreeCursor(pGrab->cursor, (Cursor) 0);

    xi2mask_free(&pGrab->xi2mask);
    free(pGrab);
}

Bool
CopyGrab(GrabPtr dst, const GrabPtr src)
{
    Mask *mdetails_mask = NULL;
    Mask *details_mask = NULL;
    XI2Mask *xi2mask;

    if (src->modifiersDetail.pMask) {
        int len = MasksPerDetailMask * sizeof(Mask);

        mdetails_mask = malloc(len);
        if (!mdetails_mask)
            return FALSE;
        memcpy(mdetails_mask, src->modifiersDetail.pMask, len);
    }

    if (src->detail.pMask) {
        int len = MasksPerDetailMask * sizeof(Mask);

        details_mask = malloc(len);
        if (!details_mask) {
            free(mdetails_mask);
            return FALSE;
        }
        memcpy(details_mask, src->detail.pMask, len);
    }

    if (!dst->xi2mask) {
        xi2mask = xi2mask_new();
        if (!xi2mask) {
            free(mdetails_mask);
            free(details_mask);
            return FALSE;
        }
    }
    else {
        xi2mask = dst->xi2mask;
        xi2mask_zero(xi2mask, -1);
    }

    *dst = *src;
    dst->modifiersDetail.pMask = mdetails_mask;
    dst->detail.pMask = details_mask;
    dst->xi2mask = xi2mask;
    dst->cursor = RefCursor(src->cursor);

    xi2mask_merge(dst->xi2mask, src->xi2mask);

    return TRUE;
}

int
DeletePassiveGrab(void *value, XID id)
{
    GrabPtr g, prev;
    GrabPtr pGrab = (GrabPtr) value;

    /* it is OK if the grab isn't found */
    prev = 0;
    for (g = (wPassiveGrabs(pGrab->window)); g; g = g->next) {
        if (pGrab == g) {
            if (prev)
                prev->next = g->next;
            else if (!(pGrab->window->optional->passiveGrabs = g->next))
                CheckWindowOptionalNeed(pGrab->window);
            break;
        }
        prev = g;
    }
    FreeGrab(pGrab);
    return Success;
}

static Mask *
DeleteDetailFromMask(Mask *pDetailMask, unsigned int detail)
{
    Mask *mask;
    int i;

    mask = malloc(sizeof(Mask) * MasksPerDetailMask);
    if (mask) {
        if (pDetailMask)
            for (i = 0; i < MasksPerDetailMask; i++)
                mask[i] = pDetailMask[i];
        else
            for (i = 0; i < MasksPerDetailMask; i++)
                mask[i] = ~0L;
        BITCLEAR(mask, detail);
    }
    return mask;
}

static Bool
IsInGrabMask(DetailRec firstDetail,
             DetailRec secondDetail, unsigned int exception)
{
    if (firstDetail.exact == exception) {
        if (firstDetail.pMask == NULL)
            return TRUE;

        /* (at present) never called with two non-null pMasks */
        if (secondDetail.exact == exception)
            return FALSE;

        if (GETBIT(firstDetail.pMask, secondDetail.exact))
            return TRUE;
    }

    return FALSE;
}

static Bool
IdenticalExactDetails(unsigned int firstExact,
                      unsigned int secondExact, unsigned int exception)
{
    if ((firstExact == exception) || (secondExact == exception))
        return FALSE;

    if (firstExact == secondExact)
        return TRUE;

    return FALSE;
}

static Bool
DetailSupersedesSecond(DetailRec firstDetail,
                       DetailRec secondDetail, unsigned int exception)
{
    if (IsInGrabMask(firstDetail, secondDetail, exception))
        return TRUE;

    if (IdenticalExactDetails(firstDetail.exact, secondDetail.exact, exception))
        return TRUE;

    return FALSE;
}

static Bool
GrabSupersedesSecond(GrabPtr pFirstGrab, GrabPtr pSecondGrab)
{
    unsigned int any_modifier = (pFirstGrab->grabtype == XI2) ?
        (unsigned int) XIAnyModifier : (unsigned int) AnyModifier;
    if (!DetailSupersedesSecond(pFirstGrab->modifiersDetail,
                                pSecondGrab->modifiersDetail, any_modifier))
        return FALSE;

    if (DetailSupersedesSecond(pFirstGrab->detail,
                               pSecondGrab->detail, (unsigned int) AnyKey))
        return TRUE;

    return FALSE;
}

/**
 * Compares two grabs and returns TRUE if the first grab matches the second
 * grab.
 *
 * A match is when
 *  - the devices set for the grab are equal (this is optional).
 *  - the event types for both grabs are equal.
 *  - XXX
 *
 * @param ignoreDevice TRUE if the device settings on the grabs are to be
 * ignored.
 * @return TRUE if the grabs match or FALSE otherwise.
 */
Bool
GrabMatchesSecond(GrabPtr pFirstGrab, GrabPtr pSecondGrab, Bool ignoreDevice)
{
    unsigned int any_modifier = (pFirstGrab->grabtype == XI2) ?
        (unsigned int) XIAnyModifier : (unsigned int) AnyModifier;

    if (pFirstGrab->grabtype != pSecondGrab->grabtype)
        return FALSE;

    if (pFirstGrab->grabtype == XI2) {
        if (pFirstGrab->device == inputInfo.all_devices ||
            pSecondGrab->device == inputInfo.all_devices) {
            /* do nothing */
        }
        else if (pFirstGrab->device == inputInfo.all_master_devices) {
            if (pSecondGrab->device != inputInfo.all_master_devices &&
                !IsMaster(pSecondGrab->device))
                return FALSE;
        }
        else if (pSecondGrab->device == inputInfo.all_master_devices) {
            if (pFirstGrab->device != inputInfo.all_master_devices &&
                !IsMaster(pFirstGrab->device))
                return FALSE;
        }
        else if (pSecondGrab->device != pFirstGrab->device)
            return FALSE;
    }
    else if (!ignoreDevice &&
             ((pFirstGrab->device != pSecondGrab->device) ||
              (pFirstGrab->modifierDevice != pSecondGrab->modifierDevice)))
        return FALSE;

    if (pFirstGrab->type != pSecondGrab->type)
        return FALSE;

    if (GrabSupersedesSecond(pFirstGrab, pSecondGrab) ||
        GrabSupersedesSecond(pSecondGrab, pFirstGrab))
        return TRUE;

    if (DetailSupersedesSecond(pSecondGrab->detail, pFirstGrab->detail,
                               (unsigned int) AnyKey)
        &&
        DetailSupersedesSecond(pFirstGrab->modifiersDetail,
                               pSecondGrab->modifiersDetail, any_modifier))
        return TRUE;

    if (DetailSupersedesSecond(pFirstGrab->detail, pSecondGrab->detail,
                               (unsigned int) AnyKey)
        &&
        DetailSupersedesSecond(pSecondGrab->modifiersDetail,
                               pFirstGrab->modifiersDetail, any_modifier))
        return TRUE;

    return FALSE;
}

static Bool
GrabsAreIdentical(GrabPtr pFirstGrab, GrabPtr pSecondGrab)
{
    unsigned int any_modifier = (pFirstGrab->grabtype == XI2) ?
        (unsigned int) XIAnyModifier : (unsigned int) AnyModifier;

    if (pFirstGrab->grabtype != pSecondGrab->grabtype)
        return FALSE;

    if (pFirstGrab->device != pSecondGrab->device ||
        (pFirstGrab->modifierDevice != pSecondGrab->modifierDevice) ||
        (pFirstGrab->type != pSecondGrab->type))
        return FALSE;

    if (!(DetailSupersedesSecond(pFirstGrab->detail,
                                 pSecondGrab->detail,
                                 (unsigned int) AnyKey) &&
          DetailSupersedesSecond(pSecondGrab->detail,
                                 pFirstGrab->detail, (unsigned int) AnyKey)))
        return FALSE;

    if (!(DetailSupersedesSecond(pFirstGrab->modifiersDetail,
                                 pSecondGrab->modifiersDetail,
                                 any_modifier) &&
          DetailSupersedesSecond(pSecondGrab->modifiersDetail,
                                 pFirstGrab->modifiersDetail, any_modifier)))
        return FALSE;

    return TRUE;
}

/**
 * Prepend the new grab to the list of passive grabs on the window.
 * Any previously existing grab that matches the new grab will be removed.
 * Adding a new grab that would override another client's grab will result in
 * a BadAccess.
 *
 * @return Success or X error code on failure.
 */
int
AddPassiveGrabToList(ClientPtr client, GrabPtr pGrab)
{
    GrabPtr grab;
    Mask access_mode = DixGrabAccess;
    int rc;

    for (grab = wPassiveGrabs(pGrab->window); grab; grab = grab->next) {
        if (GrabMatchesSecond(pGrab, grab, (pGrab->grabtype == CORE))) {
            if (CLIENT_BITS(pGrab->resource) != CLIENT_BITS(grab->resource)) {
                FreeGrab(pGrab);
                return BadAccess;
            }
        }
    }

    if (pGrab->keyboardMode == GrabModeSync ||
        pGrab->pointerMode == GrabModeSync)
        access_mode |= DixFreezeAccess;
    rc = XaceHook(XACE_DEVICE_ACCESS, client, pGrab->device, access_mode);
    if (rc != Success)
        return rc;

    /* Remove all grabs that match the new one exactly */
    for (grab = wPassiveGrabs(pGrab->window); grab; grab = grab->next) {
        if (GrabsAreIdentical(pGrab, grab)) {
            DeletePassiveGrabFromList(grab);
            break;
        }
    }

    if (!pGrab->window->optional && !MakeWindowOptional(pGrab->window)) {
        FreeGrab(pGrab);
        return BadAlloc;
    }

    pGrab->next = pGrab->window->optional->passiveGrabs;
    pGrab->window->optional->passiveGrabs = pGrab;
    if (AddResource(pGrab->resource, RT_PASSIVEGRAB, (void *) pGrab))
        return Success;
    return BadAlloc;
}

/* the following is kinda complicated, because we need to be able to back out
 * if any allocation fails
 */

Bool
DeletePassiveGrabFromList(GrabPtr pMinuendGrab)
{
    GrabPtr grab;
    GrabPtr *deletes, *adds;
    Mask ***updates, **details;
    int i, ndels, nadds, nups;
    Bool ok;
    unsigned int any_modifier;
    unsigned int any_key;

#define UPDATE(mask,exact) \
	if (!(details[nups] = DeleteDetailFromMask(mask, exact))) \
	  ok = FALSE; \
	else \
	  updates[nups++] = &(mask)

    i = 0;
    for (grab = wPassiveGrabs(pMinuendGrab->window); grab; grab = grab->next)
        i++;
    if (!i)
        return TRUE;
    deletes = xallocarray(i, sizeof(GrabPtr));
    adds = xallocarray(i, sizeof(GrabPtr));
    updates = xallocarray(i, sizeof(Mask **));
    details = xallocarray(i, sizeof(Mask *));
    if (!deletes || !adds || !updates || !details) {
        free(details);
        free(updates);
        free(adds);
        free(deletes);
        return FALSE;
    }

    any_modifier = (pMinuendGrab->grabtype == XI2) ?
        (unsigned int) XIAnyModifier : (unsigned int) AnyModifier;
    any_key = (pMinuendGrab->grabtype == XI2) ?
        (unsigned int) XIAnyKeycode : (unsigned int) AnyKey;
    ndels = nadds = nups = 0;
    ok = TRUE;
    for (grab = wPassiveGrabs(pMinuendGrab->window);
         grab && ok; grab = grab->next) {
        if ((CLIENT_BITS(grab->resource) != CLIENT_BITS(pMinuendGrab->resource))
            || !GrabMatchesSecond(grab, pMinuendGrab, (grab->grabtype == CORE)))
            continue;
        if (GrabSupersedesSecond(pMinuendGrab, grab)) {
            deletes[ndels++] = grab;
        }
        else if ((grab->detail.exact == any_key)
                 && (grab->modifiersDetail.exact != any_modifier)) {
            UPDATE(grab->detail.pMask, pMinuendGrab->detail.exact);
        }
        else if ((grab->modifiersDetail.exact == any_modifier)
                 && (grab->detail.exact != any_key)) {
            UPDATE(grab->modifiersDetail.pMask,
                   pMinuendGrab->modifiersDetail.exact);
        }
        else if ((pMinuendGrab->detail.exact != any_key)
                 && (pMinuendGrab->modifiersDetail.exact != any_modifier)) {
            GrabPtr pNewGrab;
            GrabParameters param;

            UPDATE(grab->detail.pMask, pMinuendGrab->detail.exact);

            memset(&param, 0, sizeof(param));
            param.ownerEvents = grab->ownerEvents;
            param.this_device_mode = grab->keyboardMode;
            param.other_devices_mode = grab->pointerMode;
            param.modifiers = any_modifier;

            pNewGrab = CreateGrab(CLIENT_ID(grab->resource), grab->device,
                                  grab->modifierDevice, grab->window,
                                  grab->grabtype,
                                  (GrabMask *) &grab->eventMask,
                                  &param, (int) grab->type,
                                  pMinuendGrab->detail.exact,
                                  grab->confineTo, grab->cursor);
            if (!pNewGrab)
                ok = FALSE;
            else if (!(pNewGrab->modifiersDetail.pMask =
                       DeleteDetailFromMask(grab->modifiersDetail.pMask,
                                            pMinuendGrab->modifiersDetail.
                                            exact))
                     || (!pNewGrab->window->optional &&
                         !MakeWindowOptional(pNewGrab->window))) {
                FreeGrab(pNewGrab);
                ok = FALSE;
            }
            else if (!AddResource(pNewGrab->resource, RT_PASSIVEGRAB,
                                  (void *) pNewGrab))
                ok = FALSE;
            else
                adds[nadds++] = pNewGrab;
        }
        else if (pMinuendGrab->detail.exact == any_key) {
            UPDATE(grab->modifiersDetail.pMask,
                   pMinuendGrab->modifiersDetail.exact);
        }
        else {
            UPDATE(grab->detail.pMask, pMinuendGrab->detail.exact);
        }
    }

    if (!ok) {
        for (i = 0; i < nadds; i++)
            FreeResource(adds[i]->resource, RT_NONE);
        for (i = 0; i < nups; i++)
            free(details[i]);
    }
    else {
        for (i = 0; i < ndels; i++)
            FreeResource(deletes[i]->resource, RT_NONE);
        for (i = 0; i < nadds; i++) {
            grab = adds[i];
            grab->next = grab->window->optional->passiveGrabs;
            grab->window->optional->passiveGrabs = grab;
        }
        for (i = 0; i < nups; i++) {
            free(*updates[i]);
            *updates[i] = details[i];
        }
    }
    free(details);
    free(updates);
    free(adds);
    free(deletes);
    return ok;

#undef UPDATE
}

Bool
GrabIsPointerGrab(GrabPtr grab)
{
    return (grab->type == ButtonPress ||
            grab->type == DeviceButtonPress || grab->type == XI_ButtonPress);
}

Bool
GrabIsKeyboardGrab(GrabPtr grab)
{
    return (grab->type == KeyPress ||
            grab->type == DeviceKeyPress || grab->type == XI_KeyPress);
}