aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/beam/erl_node_tables.c
blob: 6d827c6bda202361c6f95bdae203af0cbf9337b5 (plain) (blame)
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
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 2001-2013. All Rights Reserved.
 *
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * %CopyrightEnd%
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include "global.h"
#include "erl_node_tables.h"
#include "dist.h"
#include "big.h"
#include "error.h"
#include "erl_thr_progress.h"
#include "dtrace-wrapper.h"

Hash erts_dist_table;
Hash erts_node_table;
erts_smp_rwmtx_t erts_dist_table_rwmtx;
erts_smp_rwmtx_t erts_node_table_rwmtx;

DistEntry *erts_hidden_dist_entries;
DistEntry *erts_visible_dist_entries;
DistEntry *erts_not_connected_dist_entries;
Sint erts_no_of_hidden_dist_entries;
Sint erts_no_of_visible_dist_entries;
Sint erts_no_of_not_connected_dist_entries;

DistEntry *erts_this_dist_entry;
ErlNode *erts_this_node;
char erts_this_node_sysname_BUFFER[256],
    *erts_this_node_sysname = "uninitialized yet";

static Uint node_entries;
static Uint dist_entries;

static int references_atoms_need_init = 1;

/* -- The distribution table ---------------------------------------------- */

#ifdef DEBUG
static int
is_in_de_list(DistEntry *dep, DistEntry *dep_list)
{
    DistEntry *tdep;
    for(tdep = dep_list; tdep; tdep = tdep->next)
	if(tdep == dep)
	    return 1;
    return 0;
}
#endif

static HashValue
dist_table_hash(void *dep)
{
    return atom_tab(atom_val(((DistEntry *) dep)->sysname))->slot.bucket.hvalue;
}

static int
dist_table_cmp(void *dep1, void *dep2)
{
    return (((DistEntry *) dep1)->sysname == ((DistEntry *) dep2)->sysname
	    ? 0 : 1);
}

static void*
dist_table_alloc(void *dep_tmpl)
{
    Eterm chnl_nr;
    Eterm sysname;
    DistEntry *dep;
    erts_smp_rwmtx_opt_t rwmtx_opt = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER;
    rwmtx_opt.type = ERTS_SMP_RWMTX_TYPE_FREQUENT_READ;

    if(((DistEntry *) dep_tmpl) == erts_this_dist_entry)
	return dep_tmpl;

    sysname = ((DistEntry *) dep_tmpl)->sysname;
    chnl_nr = make_small((Uint) atom_val(sysname));
    dep = (DistEntry *) erts_alloc(ERTS_ALC_T_DIST_ENTRY, sizeof(DistEntry));

    dist_entries++;

    dep->prev				= NULL;
    erts_refc_init(&dep->refc, -1);
    erts_smp_rwmtx_init_opt_x(&dep->rwmtx, &rwmtx_opt, "dist_entry", chnl_nr);
    dep->sysname			= sysname;
    dep->cid				= NIL;
    dep->connection_id			= 0;
    dep->status				= 0;
    dep->flags				= 0;
    dep->version			= 0;

    erts_smp_mtx_init_x(&dep->lnk_mtx, "dist_entry_links", chnl_nr);
    dep->node_links			= NULL;
    dep->nlinks				= NULL;
    dep->monitors			= NULL;

    erts_smp_mtx_init_x(&dep->qlock, "dist_entry_out_queue", chnl_nr);
    dep->qflgs				= 0;
    dep->qsize				= 0;
    dep->out_queue.first		= NULL;
    dep->out_queue.last			= NULL;
    dep->suspended			= NULL;

    dep->finalized_out_queue.first	= NULL;
    dep->finalized_out_queue.last	= NULL;

    erts_smp_atomic_init_nob(&dep->dist_cmd_scheduled, 0);
    erts_port_task_handle_init(&dep->dist_cmd);
    dep->send				= NULL;
    dep->cache				= NULL;

    /* Link in */

    /* All new dist entries are "not connected" */
    dep->next = erts_not_connected_dist_entries;
    if(erts_not_connected_dist_entries) {
	ASSERT(erts_not_connected_dist_entries->prev == NULL);
	erts_not_connected_dist_entries->prev = dep;
    }
    erts_not_connected_dist_entries = dep;
    erts_no_of_not_connected_dist_entries++;

    return (void *) dep;
}

static void
dist_table_free(void *vdep)
{
    DistEntry *dep = (DistEntry *) vdep;

    if(dep == erts_this_dist_entry)
	return;

    ASSERT(is_nil(dep->cid));
    ASSERT(dep->nlinks == NULL);
    ASSERT(dep->node_links == NULL);
    ASSERT(dep->monitors == NULL);

    /* Link out */

    /* All dist entries about to be removed are "not connected" */

    if(dep->prev) {
	ASSERT(is_in_de_list(dep, erts_not_connected_dist_entries));
	dep->prev->next = dep->next;
    }
    else {
	ASSERT(erts_not_connected_dist_entries == dep);
	erts_not_connected_dist_entries = dep->next;
    }

    if(dep->next)
	dep->next->prev = dep->prev;

    ASSERT(erts_no_of_not_connected_dist_entries > 0);
    erts_no_of_not_connected_dist_entries--;

    ASSERT(!dep->cache);
    erts_smp_rwmtx_destroy(&dep->rwmtx);
    erts_smp_mtx_destroy(&dep->lnk_mtx);
    erts_smp_mtx_destroy(&dep->qlock);

#ifdef DEBUG
    sys_memset(vdep, 0x77, sizeof(DistEntry));
#endif
    erts_free(ERTS_ALC_T_DIST_ENTRY, (void *) dep);

    ASSERT(dist_entries > 1);
    dist_entries--;
}


void
erts_dist_table_info(int to, void *to_arg)
{
    int lock = !ERTS_IS_CRASH_DUMPING;
    if (lock)
	erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
    hash_info(to, to_arg, &erts_dist_table);
    if (lock)
	erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
}

DistEntry *
erts_channel_no_to_dist_entry(Uint cno)
{
/*
 * For this node (and previous incarnations of this node),
 * ERST_INTERNAL_CHANNEL_NO (will always be 0 I guess) is used as
 * channel no. For other nodes, the atom index of the atom corresponding
 * to the node name is used as channel no.
 */
    if(cno == ERST_INTERNAL_CHANNEL_NO) {
	erts_refc_inc(&erts_this_dist_entry->refc, 2);
	return erts_this_dist_entry;
    }

    if((cno > MAX_ATOM_INDEX)
       || (cno >= atom_table_size())
       ||  (atom_tab(cno) == NULL))
	return NULL;
        
    /* cno is a valid atom index; find corresponding dist entry (if there
       is one) */
    return erts_find_dist_entry(make_atom(cno));
}


DistEntry *
erts_sysname_to_connected_dist_entry(Eterm sysname)
{
    DistEntry de;
    DistEntry *res_dep;
    de.sysname = sysname;
  
    if(erts_this_dist_entry->sysname == sysname) {
	erts_refc_inc(&erts_this_dist_entry->refc, 2);
	return erts_this_dist_entry;
    }

    erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
    res_dep = (DistEntry *) hash_get(&erts_dist_table, (void *) &de);
    if (res_dep) {
	erts_aint_t refc = erts_refc_inctest(&res_dep->refc, 1);
	if (refc < 2) /* Pending delete */
	    erts_refc_inc(&res_dep->refc, 1);
    }
    erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
    if (res_dep) {
	int deref;
	erts_smp_rwmtx_rlock(&res_dep->rwmtx);
	deref = is_nil(res_dep->cid);
	erts_smp_rwmtx_runlock(&res_dep->rwmtx);
	if (deref) {
	    erts_deref_dist_entry(res_dep);
	    res_dep = NULL;
	}
    }
    return res_dep;
}

DistEntry *erts_find_or_insert_dist_entry(Eterm sysname)
{
    DistEntry *res;
    DistEntry de;
    erts_aint_t refc;
    res = erts_find_dist_entry(sysname);
    if (res)
	return res;
    de.sysname = sysname;
    erts_smp_rwmtx_rwlock(&erts_dist_table_rwmtx);
    res = hash_put(&erts_dist_table, (void *) &de);
    refc = erts_refc_inctest(&res->refc, 0);
    if (refc < 2) /* New or pending delete */
	erts_refc_inc(&res->refc, 1);
    erts_smp_rwmtx_rwunlock(&erts_dist_table_rwmtx);
    return res;
}

DistEntry *erts_find_dist_entry(Eterm sysname)
{
    DistEntry *res;
    DistEntry de;
    de.sysname = sysname;
    erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
    res = hash_get(&erts_dist_table, (void *) &de);
    if (res) {
	erts_aint_t refc = erts_refc_inctest(&res->refc, 1);
	if (refc < 2) /* Pending delete */
	    erts_refc_inc(&res->refc, 1);
    }
    erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
    return res;
}

void erts_delete_dist_entry(DistEntry *dep)
{
    ASSERT(dep != erts_this_dist_entry);
    if(dep != erts_this_dist_entry) {
	erts_smp_rwmtx_rwlock(&erts_dist_table_rwmtx);
	/*
	 * Another thread might have looked up this dist entry after
	 * we decided to delete it (refc became zero). If so, the other
	 * thread incremented refc twice. Once for the new reference
	 * and once for this thread. Therefore, delete dist entry if
	 * refc is 0 or -1 after a decrement.
	 */
	if (erts_refc_dectest(&dep->refc, -1) <= 0)
	    (void) hash_erase(&erts_dist_table, (void *) dep);
	erts_smp_rwmtx_rwunlock(&erts_dist_table_rwmtx);
    }
}

Uint
erts_dist_table_size(void)
{
    Uint res;
#ifdef DEBUG
    HashInfo hi;
    DistEntry *dep;
    int i;
#endif
    int lock = !ERTS_IS_CRASH_DUMPING;

    if (lock)
	erts_smp_rwmtx_rlock(&erts_dist_table_rwmtx);
#ifdef DEBUG
    hash_get_info(&hi, &erts_dist_table);
    ASSERT(dist_entries == hi.objs);

    i = 0;
    for(dep = erts_visible_dist_entries; dep; dep = dep->next)
	i++;
    ASSERT(i == erts_no_of_visible_dist_entries);
    i = 0;
    for(dep = erts_hidden_dist_entries; dep; dep = dep->next)
	i++;
    ASSERT(i == erts_no_of_hidden_dist_entries);
    i = 0;
    for(dep = erts_not_connected_dist_entries; dep; dep = dep->next)
	i++;
    ASSERT(i == erts_no_of_not_connected_dist_entries);

    ASSERT(dist_entries == (erts_no_of_visible_dist_entries
			    + erts_no_of_hidden_dist_entries
			    + erts_no_of_not_connected_dist_entries
			    + 1 /* erts_this_dist_entry */));
#endif

    res = (hash_table_sz(&erts_dist_table)
	   + dist_entries*sizeof(DistEntry)
	   + erts_dist_cache_size());
    if (lock)
	erts_smp_rwmtx_runlock(&erts_dist_table_rwmtx);
    return res;
}

void
erts_set_dist_entry_not_connected(DistEntry *dep)
{
    ERTS_SMP_LC_ASSERT(erts_lc_is_de_rwlocked(dep));
    erts_smp_rwmtx_rwlock(&erts_dist_table_rwmtx);

    ASSERT(dep != erts_this_dist_entry);
    ASSERT(is_internal_port(dep->cid));

    if(dep->flags & DFLAG_PUBLISHED) {
	if(dep->prev) {
	    ASSERT(is_in_de_list(dep, erts_visible_dist_entries));
	    dep->prev->next = dep->next;
	}
	else {
	    ASSERT(erts_visible_dist_entries == dep);
	    erts_visible_dist_entries = dep->next;
	}

	ASSERT(erts_no_of_visible_dist_entries > 0);
	erts_no_of_visible_dist_entries--;
    }
    else {
	if(dep->prev) {
	    ASSERT(is_in_de_list(dep, erts_hidden_dist_entries));
	    dep->prev->next = dep->next;
	}
	else {
	    ASSERT(erts_hidden_dist_entries == dep);
	    erts_hidden_dist_entries = dep->next;
	}

	ASSERT(erts_no_of_hidden_dist_entries > 0);
	erts_no_of_hidden_dist_entries--;
    }

    if(dep->next)
	dep->next->prev = dep->prev;

    dep->status &= ~ERTS_DE_SFLG_CONNECTED;
    dep->flags = 0;
    dep->prev = NULL;
    dep->cid = NIL;

    dep->next = erts_not_connected_dist_entries;
    if(erts_not_connected_dist_entries) {
	ASSERT(erts_not_connected_dist_entries->prev == NULL);
	erts_not_connected_dist_entries->prev = dep;
    }
    erts_not_connected_dist_entries = dep;
    erts_no_of_not_connected_dist_entries++;
    erts_smp_rwmtx_rwunlock(&erts_dist_table_rwmtx);
}

void
erts_set_dist_entry_connected(DistEntry *dep, Eterm cid, Uint flags)
{
    ERTS_SMP_LC_ASSERT(erts_lc_is_de_rwlocked(dep));
    erts_smp_rwmtx_rwlock(&erts_dist_table_rwmtx);

    ASSERT(dep != erts_this_dist_entry);
    ASSERT(is_nil(dep->cid));
    ASSERT(is_internal_port(cid));

    if(dep->prev) {
	ASSERT(is_in_de_list(dep, erts_not_connected_dist_entries));
	dep->prev->next = dep->next;
    }
    else {
	ASSERT(erts_not_connected_dist_entries == dep);
	erts_not_connected_dist_entries = dep->next;
    }

    if(dep->next)
	dep->next->prev = dep->prev;

    ASSERT(erts_no_of_not_connected_dist_entries > 0);
    erts_no_of_not_connected_dist_entries--;

    dep->status |= ERTS_DE_SFLG_CONNECTED;
    dep->flags = flags;
    dep->cid = cid;
    dep->connection_id++;
    dep->connection_id &= ERTS_DIST_EXT_CON_ID_MASK;
    dep->prev = NULL;

    if(flags & DFLAG_PUBLISHED) {
	dep->next = erts_visible_dist_entries;
	if(erts_visible_dist_entries) {
	    ASSERT(erts_visible_dist_entries->prev == NULL);
	    erts_visible_dist_entries->prev = dep;
	}
	erts_visible_dist_entries = dep;
	erts_no_of_visible_dist_entries++;
    }
    else {
	dep->next = erts_hidden_dist_entries;
	if(erts_hidden_dist_entries) {
	    ASSERT(erts_hidden_dist_entries->prev == NULL);
	    erts_hidden_dist_entries->prev = dep;
	}
	erts_hidden_dist_entries = dep;
	erts_no_of_hidden_dist_entries++;
    }
    erts_smp_rwmtx_rwunlock(&erts_dist_table_rwmtx);
}

/* -- Node table --------------------------------------------------------- */

/* Some large primes */
#define PRIME0 ((HashValue) 268438039)
#define PRIME1 ((HashValue) 268440479)
#define PRIME2 ((HashValue) 268439161)
#define PRIME3 ((HashValue) 268437017)

static HashValue
node_table_hash(void *venp)
{
    Uint32 cre = ((ErlNode *) venp)->creation;
    HashValue h = atom_tab(atom_val(((ErlNode *) venp)->sysname))->slot.bucket.hvalue;

    h *= PRIME0;
    h += cre & 0xff;

#if MAX_CREATION >= (1 << 8)
    h *= PRIME1;
    h += (cre >> 8) & 0xff;
#endif

#if MAX_CREATION >= (1 << 16)
    h *= PRIME2;
    h += (cre >> 16) & 0xff;
#endif

#if MAX_CREATION >= (1 << 24)
    h *= PRIME3;
    h += (cre >> 24) & 0xff;
#endif

#if 0
/* XXX Problems in older versions of GCC */
 #if MAX_CREATION >= (1UL << 32)
 #error "MAX_CREATION larger than size of expected creation storage (Uint32)"
 #endif
#endif
    return h;
}

static int
node_table_cmp(void *venp1, void *venp2)
{
    return ((((ErlNode *) venp1)->sysname == ((ErlNode *) venp2)->sysname
	     && ((ErlNode *) venp1)->creation == ((ErlNode *) venp2)->creation)
	    ? 0
	    : 1);
}

static void*
node_table_alloc(void *venp_tmpl)
{
    ErlNode *enp;

    if(((ErlNode *) venp_tmpl) == erts_this_node)
	return venp_tmpl;

    enp = (ErlNode *) erts_alloc(ERTS_ALC_T_NODE_ENTRY, sizeof(ErlNode));

    node_entries++;

    erts_refc_init(&enp->refc, -1);
    enp->creation = ((ErlNode *) venp_tmpl)->creation;
    enp->sysname = ((ErlNode *) venp_tmpl)->sysname;
    enp->dist_entry = erts_find_or_insert_dist_entry(((ErlNode *) venp_tmpl)->sysname);

    return (void *) enp;
}

static void
node_table_free(void *venp)
{
    ErlNode *enp = (ErlNode *) venp;

    if(enp == erts_this_node)
	return;

    erts_deref_dist_entry(enp->dist_entry);
#ifdef DEBUG
    sys_memset(venp, 0x55, sizeof(ErlNode));
#endif
    erts_free(ERTS_ALC_T_NODE_ENTRY, venp);

    ASSERT(node_entries > 1);
    node_entries--;
}

Uint
erts_node_table_size(void)
{
    Uint res;
#ifdef DEBUG
    HashInfo hi;
#endif
    int lock = !ERTS_IS_CRASH_DUMPING;
    if (lock)
	erts_smp_rwmtx_rwlock(&erts_node_table_rwmtx);
#ifdef DEBUG
    hash_get_info(&hi, &erts_node_table);
    ASSERT(node_entries == hi.objs);
#endif
    res = hash_table_sz(&erts_node_table) + node_entries*sizeof(ErlNode);
    if (lock)
	erts_smp_rwmtx_rwunlock(&erts_node_table_rwmtx);
    return res;
}

void
erts_node_table_info(int to, void *to_arg)
{
    int lock = !ERTS_IS_CRASH_DUMPING;
    if (lock)
	erts_smp_rwmtx_rwlock(&erts_node_table_rwmtx);
    hash_info(to, to_arg, &erts_node_table);
    if (lock)
	erts_smp_rwmtx_rwunlock(&erts_node_table_rwmtx);
}


ErlNode *erts_find_or_insert_node(Eterm sysname, Uint creation)
{
    ErlNode *res;
    ErlNode ne;
    ne.sysname = sysname;
    ne.creation = creation;

    erts_smp_rwmtx_rlock(&erts_node_table_rwmtx);
    res = hash_get(&erts_node_table, (void *) &ne);
    if (res && res != erts_this_node) {
	erts_aint_t refc = erts_refc_inctest(&res->refc, 0);
	if (refc < 2) /* New or pending delete */
	    erts_refc_inc(&res->refc, 1);
    }
    erts_smp_rwmtx_runlock(&erts_node_table_rwmtx);
    if (res)
	return res;

    erts_smp_rwmtx_rwlock(&erts_node_table_rwmtx);
    res = hash_put(&erts_node_table, (void *) &ne);
    ASSERT(res);
    if (res != erts_this_node) {
	erts_aint_t refc = erts_refc_inctest(&res->refc, 0);
	if (refc < 2) /* New or pending delete */
	    erts_refc_inc(&res->refc, 1);
    }
    erts_smp_rwmtx_rwunlock(&erts_node_table_rwmtx);
    return res;
}

void erts_delete_node(ErlNode *enp)
{
    ASSERT(enp != erts_this_node);
    if(enp != erts_this_node) {
	erts_smp_rwmtx_rwlock(&erts_node_table_rwmtx);
	/*
	 * Another thread might have looked up this node after we
	 * decided to delete it (refc became zero). If so, the other
	 * thread incremented refc twice. Once for the new reference
	 * and once for this thread. Therefore, delete node if refc
	 * is 0 or -1 after a decrement.
	 */
	if (erts_refc_dectest(&enp->refc, -1) <= 0)
	    (void) hash_erase(&erts_node_table, (void *) enp);
	erts_smp_rwmtx_rwunlock(&erts_node_table_rwmtx);
    }
}

struct pn_data {
    int to;
    void *to_arg;
    Eterm sysname;
    int no_sysname;
    int no_total;
};

static void print_node(void *venp, void *vpndp)
{
    struct pn_data *pndp = ((struct pn_data *) vpndp);
    ErlNode *enp = ((ErlNode *) venp);

    if(pndp->sysname == NIL
       || enp->sysname == pndp->sysname) {
	if (pndp->no_sysname == 0) {
	    erts_print(pndp->to, pndp->to_arg, "Creation:");
	}
	if(pndp->sysname == NIL) {
	    erts_print(pndp->to, pndp->to_arg, "Name: %T ", enp->sysname);
	}
	erts_print(pndp->to, pndp->to_arg, " %d", enp->creation);
#ifdef DEBUG
	erts_print(pndp->to, pndp->to_arg, " (refc=%ld)",
		   erts_refc_read(&enp->refc, 1));
#endif
	pndp->no_sysname++;
    }
    pndp->no_total++;
}

void erts_print_node_info(int to,
			  void *to_arg,
			  Eterm sysname,
			  int *no_sysname,
			  int *no_total)
{
    int lock = !ERTS_IS_CRASH_DUMPING;
    struct pn_data pnd;

    pnd.to = to;
    pnd.to_arg = to_arg;
    pnd.sysname = sysname;
    pnd.no_sysname = 0;
    pnd.no_total = 0;

    if (lock)
	erts_smp_rwmtx_rwlock(&erts_node_table_rwmtx);
    hash_foreach(&erts_node_table, print_node, (void *) &pnd);
    if (pnd.no_sysname != 0) {
	erts_print(to, to_arg, "\n");
    }
    if (lock)
	erts_smp_rwmtx_rwunlock(&erts_node_table_rwmtx);

    if(no_sysname)
	*no_sysname = pnd.no_sysname;
    if(no_total)
	*no_total = pnd.no_total;
}

/* ----------------------------------------------------------------------- */

void
erts_set_this_node(Eterm sysname, Uint creation)
{
    erts_smp_rwmtx_rwlock(&erts_node_table_rwmtx);
    erts_smp_rwmtx_rwlock(&erts_dist_table_rwmtx);

    (void) hash_erase(&erts_dist_table, (void *) erts_this_dist_entry);
    erts_this_dist_entry->sysname = sysname;
    erts_this_dist_entry->creation = creation;
    (void) hash_put(&erts_dist_table, (void *) erts_this_dist_entry);

    (void) hash_erase(&erts_node_table, (void *) erts_this_node);
    erts_this_node->sysname = sysname;
    erts_this_node->creation = creation;
    erts_this_node_sysname = erts_this_node_sysname_BUFFER;
    erts_snprintf(erts_this_node_sysname, sizeof(erts_this_node_sysname_BUFFER),
                  "%T", sysname);
    (void) hash_put(&erts_node_table, (void *) erts_this_node);

    erts_smp_rwmtx_rwunlock(&erts_dist_table_rwmtx);
    erts_smp_rwmtx_rwunlock(&erts_node_table_rwmtx);

}

void erts_init_node_tables(void)
{
    erts_smp_rwmtx_opt_t rwmtx_opt = ERTS_SMP_RWMTX_OPT_DEFAULT_INITER;
    HashFunctions f;

    rwmtx_opt.type = ERTS_SMP_RWMTX_TYPE_FREQUENT_READ;
    rwmtx_opt.lived = ERTS_SMP_RWMTX_LONG_LIVED;

    f.hash  = (H_FUN)			dist_table_hash;
    f.cmp   = (HCMP_FUN)		dist_table_cmp;
    f.alloc = (HALLOC_FUN)		dist_table_alloc;
    f.free  = (HFREE_FUN)		dist_table_free;

    erts_this_dist_entry = erts_alloc(ERTS_ALC_T_DIST_ENTRY, sizeof(DistEntry));
    dist_entries = 1;

    hash_init(ERTS_ALC_T_DIST_TABLE, &erts_dist_table, "dist_table", 11, f);

    erts_hidden_dist_entries				= NULL;
    erts_visible_dist_entries				= NULL;
    erts_not_connected_dist_entries			= NULL;
    erts_no_of_hidden_dist_entries			= 0;
    erts_no_of_visible_dist_entries			= 0;
    erts_no_of_not_connected_dist_entries		= 0;

    erts_this_dist_entry->next				= NULL;
    erts_this_dist_entry->prev				= NULL;
    erts_refc_init(&erts_this_dist_entry->refc, 1); /* erts_this_node */

    erts_smp_rwmtx_init_opt_x(&erts_this_dist_entry->rwmtx,
			      &rwmtx_opt,
			      "dist_entry",
			      make_small(ERST_INTERNAL_CHANNEL_NO));
    erts_this_dist_entry->sysname			= am_Noname;
    erts_this_dist_entry->cid				= NIL;
    erts_this_dist_entry->connection_id			= 0;
    erts_this_dist_entry->status			= 0;
    erts_this_dist_entry->flags				= 0;
    erts_this_dist_entry->version			= 0;

    erts_smp_mtx_init_x(&erts_this_dist_entry->lnk_mtx,
			"dist_entry_links",
			make_small(ERST_INTERNAL_CHANNEL_NO));
    erts_this_dist_entry->node_links			= NULL;
    erts_this_dist_entry->nlinks			= NULL;
    erts_this_dist_entry->monitors			= NULL;

    erts_smp_mtx_init_x(&erts_this_dist_entry->qlock,
			"dist_entry_out_queue",
			make_small(ERST_INTERNAL_CHANNEL_NO));
    erts_this_dist_entry->qflgs				= 0;
    erts_this_dist_entry->qsize				= 0;
    erts_this_dist_entry->out_queue.first		= NULL;
    erts_this_dist_entry->out_queue.last		= NULL;
    erts_this_dist_entry->suspended			= NULL;

    erts_this_dist_entry->finalized_out_queue.first	= NULL;
    erts_this_dist_entry->finalized_out_queue.last	= NULL;
    erts_smp_atomic_init_nob(&erts_this_dist_entry->dist_cmd_scheduled, 0);
    erts_port_task_handle_init(&erts_this_dist_entry->dist_cmd);
    erts_this_dist_entry->send				= NULL;
    erts_this_dist_entry->cache				= NULL;

    (void) hash_put(&erts_dist_table, (void *) erts_this_dist_entry);

    f.hash  = (H_FUN)      			node_table_hash;
    f.cmp   = (HCMP_FUN)   			node_table_cmp;
    f.alloc = (HALLOC_FUN) 			node_table_alloc;
    f.free  = (HFREE_FUN)  			node_table_free;

    hash_init(ERTS_ALC_T_NODE_TABLE, &erts_node_table, "node_table", 11, f);

    erts_this_node = erts_alloc(ERTS_ALC_T_NODE_ENTRY, sizeof(ErlNode));
    node_entries = 1;

    erts_refc_init(&erts_this_node->refc, 1); /* The system itself */
    erts_this_node->sysname			= am_Noname;
    erts_this_node->creation			= 0;
    erts_this_node->dist_entry			= erts_this_dist_entry;
    erts_this_node_sysname = erts_this_node_sysname_BUFFER;
    erts_snprintf(erts_this_node_sysname, sizeof(erts_this_node_sysname_BUFFER),
                  "%T", erts_this_node->sysname);

    (void) hash_put(&erts_node_table, (void *) erts_this_node);

    erts_smp_rwmtx_init_opt(&erts_node_table_rwmtx, &rwmtx_opt, "node_table");
    erts_smp_rwmtx_init_opt(&erts_dist_table_rwmtx, &rwmtx_opt, "dist_table");

    references_atoms_need_init = 1;
}

#ifdef ERTS_SMP
#ifdef ERTS_ENABLE_LOCK_CHECK
int erts_lc_is_de_rwlocked(DistEntry *dep)
{
    return erts_smp_lc_rwmtx_is_rwlocked(&dep->rwmtx);
}
int erts_lc_is_de_rlocked(DistEntry *dep)
{
    return erts_smp_lc_rwmtx_is_rlocked(&dep->rwmtx);
}
#endif
#endif

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
 * The following is only supposed to be used for testing, and debugging.     *
 *                                                                           *
 * erts_get_node_and_dist_references() returns a table of all references to  *
 * all entries in the node and dist tables. The hole system will be searched *
 * at once. This will give a consistent view over the references, but can    *
 * can damage the real-time properties of the system.                        *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include "erl_db.h"

#undef  INIT_AM
#define INIT_AM(S) AM_ ## S = am_atom_put(#S, sizeof(#S) - 1)

static Eterm AM_heap;
static Eterm AM_link;
static Eterm AM_monitor;
static Eterm AM_process;
static Eterm AM_port;
static Eterm AM_ets;
static Eterm AM_binary;
static Eterm AM_match_spec;
static Eterm AM_control;
static Eterm AM_dist;
static Eterm AM_node;
static Eterm AM_dist_references;
static Eterm AM_node_references;
static Eterm AM_system;
static Eterm AM_timer;

static void setup_reference_table(void);
static Eterm reference_table_term(Uint **hpp, Uint *szp);
static void delete_reference_table(void);

#if BIG_UINT_HEAP_SIZE > 3 /* 2-tuple */
#define ID_HEAP_SIZE BIG_UINT_HEAP_SIZE
#else
#define ID_HEAP_SIZE 3 /* 2-tuple */
#endif

typedef struct node_referrer_ {
    struct node_referrer_ *next;
    int heap_ref;
    int link_ref;
    int monitor_ref;
    int ets_ref;
    int bin_ref;
    int timer_ref;
    int system_ref;
    Eterm id;
    Uint id_heap[ID_HEAP_SIZE];
} NodeReferrer;

typedef struct {
    ErlNode *node;
    NodeReferrer *referrers;
} ReferredNode;

typedef struct dist_referrer_ {
    struct dist_referrer_ *next;
    int heap_ref;
    int node_ref;
    int ctrl_ref;
    Eterm id;
    Uint creation;
} DistReferrer;

typedef struct {
    DistEntry *dist;
    DistReferrer *referrers;
} ReferredDist;

typedef struct inserted_bin_ {
    struct inserted_bin_ *next;
    Binary *bin_val;
} InsertedBin;

static ReferredNode *referred_nodes;
static int no_referred_nodes;
static ReferredDist *referred_dists;
static int no_referred_dists;
static InsertedBin *inserted_bins;

Eterm
erts_get_node_and_dist_references(struct process *proc)
{
    Uint *hp;
    Uint size;
    Eterm res;
#ifdef DEBUG
    Uint *endp;
#endif

    erts_smp_proc_unlock(proc, ERTS_PROC_LOCK_MAIN);
    erts_smp_thr_progress_block();
    /* No need to lock any thing since we are alone... */

    if (references_atoms_need_init) {
	INIT_AM(heap);
	INIT_AM(link);
	INIT_AM(monitor);
	INIT_AM(process);
	INIT_AM(port);
	INIT_AM(ets);
	INIT_AM(binary);
	INIT_AM(match_spec);
	INIT_AM(control);
	INIT_AM(dist);
	INIT_AM(node);
	INIT_AM(dist_references);
	INIT_AM(node_references);
	INIT_AM(timer);
	INIT_AM(system);
	references_atoms_need_init = 0;
    }

    setup_reference_table();

    /* Get term size */
    size = 0;
    (void) reference_table_term(NULL, &size);

    hp = HAlloc(proc, size);
#ifdef DEBUG
    ASSERT(size > 0);
    endp = hp + size;
#endif

    /* Write term */
    res = reference_table_term(&hp, NULL);

    ASSERT(endp == hp);

    delete_reference_table();

    erts_smp_thr_progress_unblock();
    erts_smp_proc_lock(proc, ERTS_PROC_LOCK_MAIN);
    return res;
}

#define HEAP_REF 1
#define LINK_REF 2
#define ETS_REF  3 
#define BIN_REF  4
#define NODE_REF 5
#define CTRL_REF 6
#define MONITOR_REF 7
#define TIMER_REF 8
#define SYSTEM_REF 9

#define INC_TAB_SZ 10

static void
insert_dist_referrer(ReferredDist *referred_dist,
		    int type,
		    Eterm id,
		    Uint creation)
{
    DistReferrer *drp;

    for(drp = referred_dist->referrers; drp; drp = drp->next)
	if(id == drp->id && (type == CTRL_REF
			     || creation == drp->creation))
	    break;

    if(!drp) {
	drp = (DistReferrer *) erts_alloc(ERTS_ALC_T_NC_TMP,
					  sizeof(DistReferrer));
	drp->next = referred_dist->referrers;
	referred_dist->referrers = drp;
	drp->id = id;
	drp->creation = creation;
	drp->heap_ref = 0;
	drp->node_ref = 0;
	drp->ctrl_ref = 0;
    }

    switch (type) {
    case NODE_REF:	drp->node_ref++;	break;
    case CTRL_REF:	drp->ctrl_ref++;	break;
    case HEAP_REF:	drp->heap_ref++;	break;
    default:		ASSERT(0);
    }
}

static void
insert_dist_entry(DistEntry *dist, int type, Eterm id, Uint creation)
{
    ReferredDist *rdp = NULL;
    int i;

    for(i = 0; i < no_referred_dists; i++) {
	if(dist == referred_dists[i].dist) {
	    rdp = &referred_dists[i];
	    break;
	}
    }

    if(!rdp)
	erl_exit(1,
		 "Reference to non-existing distribution table entry found!\n");

    insert_dist_referrer(rdp, type, id, creation);
}

static void
insert_node_referrer(ReferredNode *referred_node, int type, Eterm id)
{
    NodeReferrer *nrp;

    for(nrp = referred_node->referrers; nrp; nrp = nrp->next)
	if(EQ(id, nrp->id))
	    break;

    if(!nrp) {
	nrp = (NodeReferrer *) erts_alloc(ERTS_ALC_T_NC_TMP,
					  sizeof(NodeReferrer));
	nrp->next = referred_node->referrers;
	referred_node->referrers = nrp;
	if(IS_CONST(id))
	    nrp->id = id;
	else {
	    Uint *hp = &nrp->id_heap[0];
	    ASSERT(is_big(id) || is_tuple(id));
	    nrp->id = copy_struct(id, size_object(id), &hp, NULL);
	}
	nrp->heap_ref = 0;
	nrp->link_ref = 0;
	nrp->monitor_ref = 0;
	nrp->ets_ref = 0;
	nrp->bin_ref = 0;
	nrp->timer_ref = 0;
	nrp->system_ref = 0;
    }

    switch (type) {
    case HEAP_REF:	nrp->heap_ref++;	break;
    case LINK_REF:	nrp->link_ref++;	break;
    case ETS_REF:	nrp->ets_ref++;		break;
    case BIN_REF:	nrp->bin_ref++;		break;
    case MONITOR_REF:   nrp->monitor_ref++;     break;
    case TIMER_REF:	nrp->timer_ref++;	break;
    case SYSTEM_REF:	nrp->system_ref++;	break;
    default:		ASSERT(0);
    }
}

static void
insert_node(ErlNode *node, int type, Eterm id)
{
    int i;
    ReferredNode *rnp = NULL;
    for(i = 0; i < no_referred_nodes; i++) {
	if(node == referred_nodes[i].node) {
	    rnp = &referred_nodes[i];
	    break;
	}
    }

    if (!rnp)
	erl_exit(1, "Reference to non-existing node table entry found!\n");

    insert_node_referrer(rnp, type, id);
}

static void
insert_erl_node(void *venp, void *unused)
{
    ErlNode *enp = (ErlNode *) venp;

    insert_dist_entry(enp->dist_entry, NODE_REF, enp->sysname, enp->creation);
}

struct insert_offheap2_arg {
    int type;
    Eterm id;
};

static void insert_offheap(ErlOffHeap *, int, Eterm);

static void
insert_offheap2(ErlOffHeap *oh, void *arg) 
{
    struct insert_offheap2_arg *a = (struct insert_offheap2_arg *) arg;
    insert_offheap(oh, a->type, a->id);
}

static void
insert_offheap(ErlOffHeap *oh, int type, Eterm id)
{
    union erl_off_heap_ptr u;
    struct insert_offheap2_arg a;
    a.type = BIN_REF;

    for (u.hdr = oh->first; u.hdr; u.hdr = u.hdr->next) {
	switch (thing_subtag(u.hdr->thing_word)) {
	case REFC_BINARY_SUBTAG:
	    if(IsMatchProgBinary(u.pb->val)) {
		InsertedBin *ib;
		int insert_bin = 1;
		for (ib = inserted_bins; ib; ib = ib->next)
		    if(ib->bin_val == u.pb->val) {
			insert_bin = 0;
			break;
		    }
		if (insert_bin) {
#if HALFWORD_HEAP
		    UWord val = (UWord) u.pb->val;
		    DeclareTmpHeapNoproc(id_heap,BIG_UINT_HEAP_SIZE*2); /* extra place allocated */
#else
		    DeclareTmpHeapNoproc(id_heap,BIG_UINT_HEAP_SIZE);
#endif
		    Uint *hp = &id_heap[0];
		    InsertedBin *nib;
#if HALFWORD_HEAP
		    int actual_need = BIG_UWORD_HEAP_SIZE(val);
		    ASSERT(actual_need <= (BIG_UINT_HEAP_SIZE*2));
		    UseTmpHeapNoproc(actual_need);
		    a.id = erts_bld_uword(&hp, NULL, (UWord) val);
#else
		    UseTmpHeapNoproc(BIG_UINT_HEAP_SIZE);
		    a.id = erts_bld_uint(&hp, NULL, (Uint) u.pb->val);
#endif
		    erts_match_prog_foreach_offheap(u.pb->val,
						    insert_offheap2,
						    (void *) &a);
		    nib = erts_alloc(ERTS_ALC_T_NC_TMP, sizeof(InsertedBin));
		    nib->bin_val = u.pb->val;
		    nib->next = inserted_bins;
		    inserted_bins = nib;
#if HALFWORD_HEAP
		    UnUseTmpHeapNoproc(actual_need);
#else
		    UnUseTmpHeapNoproc(BIG_UINT_HEAP_SIZE);
#endif
		}
	    }		
	    break;
	case FUN_SUBTAG:
	    break; /* No need to */
	default:
	    ASSERT(is_external_header(u.hdr->thing_word));
	    insert_node(u.ext->node, type, id);
	    break;
	}
    }
}

static void doit_insert_monitor(ErtsMonitor *monitor, void *p)
{
    Eterm *idp = p;
    if(is_external(monitor->pid))
	insert_node(external_thing_ptr(monitor->pid)->node, MONITOR_REF, *idp);
    if(is_external(monitor->ref))
	insert_node(external_thing_ptr(monitor->ref)->node, MONITOR_REF, *idp);
}

static void doit_insert_link(ErtsLink *lnk, void *p)
{
    Eterm *idp = p;
    if(is_external(lnk->pid))
	insert_node(external_thing_ptr(lnk->pid)->node, LINK_REF, 
		    *idp);
}


static void
insert_monitors(ErtsMonitor *monitors, Eterm id)
{
    erts_doforall_monitors(monitors,&doit_insert_monitor,&id);
}

static void
insert_links(ErtsLink *lnk, Eterm id)
{
    erts_doforall_links(lnk,&doit_insert_link,&id);
}

static void doit_insert_link2(ErtsLink *lnk, void *p)
{
    Eterm *idp = p;
    if(is_external(lnk->pid))
	insert_node(external_thing_ptr(lnk->pid)->node, LINK_REF, 
		    *idp);
    insert_links(ERTS_LINK_ROOT(lnk), *idp);
}

static void
insert_links2(ErtsLink *lnk, Eterm id)
{
    erts_doforall_links(lnk,&doit_insert_link2,&id);
}

static void
insert_ets_table(DbTable *tab, void *unused)
{
    struct insert_offheap2_arg a;
    a.type = ETS_REF;
    a.id = tab->common.id;
    erts_db_foreach_offheap(tab, insert_offheap2, (void *) &a);
}

static void
insert_bif_timer(Eterm receiver, Eterm msg, ErlHeapFragment *bp, void *arg)
{
    if (bp) {
	DeclareTmpHeapNoproc(heap,3);

	UseTmpHeapNoproc(3);
	insert_offheap(&bp->off_heap,
		       TIMER_REF,
		       (is_internal_pid(receiver)
			? receiver
			: TUPLE2(&heap[0], AM_process, receiver)));
	UnUseTmpHeapNoproc(3);
    }
}

static void
init_referred_node(void *node, void *unused)
{
    referred_nodes[no_referred_nodes].node = (ErlNode *) node;
    referred_nodes[no_referred_nodes].referrers = NULL;
    no_referred_nodes++;
}

static void
init_referred_dist(void *dist, void *unused)
{
    referred_dists[no_referred_dists].dist = (DistEntry *) dist;
    referred_dists[no_referred_dists].referrers = NULL;
    no_referred_dists++;
}

#ifdef ERTS_SMP
static void
insert_sys_msg(Eterm from, Eterm to, Eterm msg, ErlHeapFragment *bp)
{
    insert_offheap(&bp->off_heap, HEAP_REF, to);
}
#endif

static void
setup_reference_table(void)
{
    ErlHeapFragment *hfp;
    DistEntry *dep;
    HashInfo hi;
    int i, max;
    DeclareTmpHeapNoproc(heap,3);

    inserted_bins = NULL;

    hash_get_info(&hi, &erts_node_table);
    referred_nodes = erts_alloc(ERTS_ALC_T_NC_TMP,
				hi.objs*sizeof(ReferredNode));
    no_referred_nodes = 0;
    hash_foreach(&erts_node_table, init_referred_node, NULL);
    ASSERT(no_referred_nodes == hi.objs);

    hash_get_info(&hi, &erts_dist_table);
    referred_dists = erts_alloc(ERTS_ALC_T_NC_TMP,
				hi.objs*sizeof(ReferredDist));
    no_referred_dists = 0;
    hash_foreach(&erts_dist_table, init_referred_dist, NULL);
    ASSERT(no_referred_dists == hi.objs);

    /* Go through the hole system, and build a table of all references
       to ErlNode and DistEntry structures */

    UseTmpHeapNoproc(3);
    insert_node(erts_this_node,
		SYSTEM_REF,
		TUPLE2(&heap[0], AM_system, am_undefined));

    UnUseTmpHeapNoproc(3);

    max = erts_ptab_max(&erts_proc);
    /* Insert all processes */
    for (i = 0; i < max; i++) {
	Process *proc = erts_pix2proc(i);
	if (proc) {
	    ErlMessage *msg;

	    /* Insert Heap */
	    insert_offheap(&(proc->off_heap),
			   HEAP_REF,
			   proc->common.id);
	    /* Insert message buffers */
	    for(hfp = proc->mbuf; hfp; hfp = hfp->next)
		insert_offheap(&(hfp->off_heap),
			       HEAP_REF,
			       proc->common.id);
	    /* Insert msg msg buffers */
	    for (msg = proc->msg.first; msg; msg = msg->next) {
		ErlHeapFragment *heap_frag = NULL;
		if (msg->data.attached) {
		    if (is_value(ERL_MESSAGE_TERM(msg)))
			heap_frag = msg->data.heap_frag;
		    else {
			if (msg->data.dist_ext->dep)
			    insert_dist_entry(msg->data.dist_ext->dep,
					      HEAP_REF, proc->common.id, 0);
			if (is_not_nil(ERL_MESSAGE_TOKEN(msg)))
			    heap_frag = erts_dist_ext_trailer(msg->data.dist_ext);
		    }
		}
		if (heap_frag)
		    insert_offheap(&(heap_frag->off_heap),
				   HEAP_REF,
				   proc->common.id);
	    }
#ifdef ERTS_SMP
	    for (msg = proc->msg_inq.first; msg; msg = msg->next) {
		ErlHeapFragment *heap_frag = NULL;
		if (msg->data.attached) {
		    if (is_value(ERL_MESSAGE_TERM(msg)))
			heap_frag = msg->data.heap_frag;
		    else {
			if (msg->data.dist_ext->dep)
			    insert_dist_entry(msg->data.dist_ext->dep,
					      HEAP_REF, proc->common.id, 0);
			if (is_not_nil(ERL_MESSAGE_TOKEN(msg)))
			    heap_frag = erts_dist_ext_trailer(msg->data.dist_ext);
		    }
		}
		if (heap_frag)
		    insert_offheap(&(heap_frag->off_heap),
				   HEAP_REF,
				   proc->common.id);
	    }
#endif
	    /* Insert links */
	    if (ERTS_P_LINKS(proc))
		insert_links(ERTS_P_LINKS(proc), proc->common.id);
	    if (ERTS_P_MONITORS(proc))
		insert_monitors(ERTS_P_MONITORS(proc), proc->common.id);
	    /* Insert controller */
	    {
		DistEntry *dep = ERTS_PROC_GET_DIST_ENTRY(proc);
		if (dep)
		    insert_dist_entry(dep, CTRL_REF, proc->common.id, 0);
	    }
	}
    }
    
#ifdef ERTS_SMP
    erts_foreach_sys_msg_in_q(insert_sys_msg);
#endif

    /* Insert all ports */
    max = erts_ptab_max(&erts_port);
    for (i = 0; i < max; i++) {
	ErlOffHeap *ohp;
	erts_aint32_t state;
	Port *prt;

	prt = erts_pix2port(i);
	if (!prt)
	    continue;

	state = erts_atomic32_read_nob(&prt->state);
	if (state & ERTS_PORT_SFLGS_DEAD)
	    continue;

	/* Insert links */
	if (ERTS_P_LINKS(prt))
	    insert_links(ERTS_P_LINKS(prt), prt->common.id);
	/* Insert monitors */
	if (ERTS_P_MONITORS(prt))
	    insert_monitors(ERTS_P_MONITORS(prt), prt->common.id);
	/* Insert port data */
	ohp = erts_port_data_offheap(prt);
	if (ohp)
	    insert_offheap(ohp, HEAP_REF, prt->common.id);
	/* Insert controller */
	if (prt->dist_entry)
	    insert_dist_entry(prt->dist_entry,
			      CTRL_REF,
			      prt->common.id,
			      0);
    }

    { /* Add binaries stored elsewhere ... */
	ErlOffHeap oh;
	ProcBin pb[2];
	int i = 0;
	Binary *default_match_spec;
	Binary *default_meta_match_spec;

	oh.first = NULL;
	/* Only the ProcBin members thing_word, val and next will be inspected
	   (by insert_offheap()) */
#undef  ADD_BINARY
#define ADD_BINARY(Bin)				 	     \
	if ((Bin)) {					     \
	    pb[i].thing_word = REFC_BINARY_SUBTAG;           \
	    pb[i].val = (Bin);				     \
	    pb[i].next = oh.first;		             \
	    oh.first = (struct erl_off_heap_header*) &pb[i]; \
	    i++;				             \
	}

	erts_get_default_trace_pattern(NULL,
				       &default_match_spec,
				       &default_meta_match_spec,
				       NULL,
				       NULL);

	ADD_BINARY(default_match_spec);
	ADD_BINARY(default_meta_match_spec);

	insert_offheap(&oh, BIN_REF, AM_match_spec);
#undef  ADD_BINARY
    }

    /* Insert all dist links */

    for(dep = erts_visible_dist_entries; dep; dep = dep->next) {
	if(dep->nlinks)
	    insert_links2(dep->nlinks, dep->sysname);
	if(dep->node_links)
	    insert_links(dep->node_links, dep->sysname);
	if(dep->monitors)
	    insert_monitors(dep->monitors, dep->sysname);
    }

    for(dep = erts_hidden_dist_entries; dep; dep = dep->next) {
	if(dep->nlinks)
	    insert_links2(dep->nlinks, dep->sysname);
	if(dep->node_links)
	    insert_links(dep->node_links, dep->sysname);
	if(dep->monitors)
	    insert_monitors(dep->monitors, dep->sysname);
    }

    /* Not connected dist entries should not have any links,
       but inspect them anyway */
    for(dep = erts_not_connected_dist_entries; dep; dep = dep->next) {
	if(dep->nlinks)
	    insert_links2(dep->nlinks, dep->sysname);
	if(dep->node_links)
	    insert_links(dep->node_links, dep->sysname);
	if(dep->monitors)
	    insert_monitors(dep->monitors, dep->sysname);
    }

    /* Insert all ets tables */
    erts_db_foreach_table(insert_ets_table, NULL);

    /* Insert all bif timers */
    erts_debug_bif_timer_foreach(insert_bif_timer, NULL);

    /* Insert node table (references to dist) */
    hash_foreach(&erts_node_table, insert_erl_node, NULL);
}

/*
  Returns an erlang term on this format:

 	 {{node_references,
 	   [{{Node, Creation}, Refc,
	     [{{ReferrerType, ID},
	       [{ReferenceType,References},
		'...']},
	      '...']},
	     '...']},
 	  {dist_references,
 	   [{Node, Refc,
	     [{{ReferrerType, ID},
	       [{ReferenceType,References},
		'...']},
	      '...']},
 	    '...']}}
 */

static Eterm
reference_table_term(Uint **hpp, Uint *szp)
{
#undef  MK_2TUP
#undef  MK_3TUP
#undef  MK_CONS
#undef  MK_UINT
#define MK_2TUP(E1, E2)		erts_bld_tuple(hpp, szp, 2, (E1), (E2))
#define MK_3TUP(E1, E2, E3)	erts_bld_tuple(hpp, szp, 3, (E1), (E2), (E3))
#define MK_CONS(CAR, CDR)	erts_bld_cons(hpp, szp, (CAR), (CDR))
#define MK_UINT(UI)		erts_bld_uint(hpp, szp, (UI))
    int i;
    Eterm tup;
    Eterm tup2;
    Eterm nl = NIL;
    Eterm dl = NIL;
    Eterm nrid;

    for(i = 0; i < no_referred_nodes; i++) {
	NodeReferrer *nrp;
	Eterm nril = NIL;

	for(nrp = referred_nodes[i].referrers; nrp; nrp = nrp->next) {
	    Eterm nrl = NIL;
	    /* NodeReferenceList = [{ReferenceType,References}] */
	    if(nrp->heap_ref) {
		tup = MK_2TUP(AM_heap, MK_UINT(nrp->heap_ref));
		nrl = MK_CONS(tup, nrl);
	    }
	    if(nrp->link_ref) {
		tup = MK_2TUP(AM_link, MK_UINT(nrp->link_ref));
		nrl = MK_CONS(tup, nrl);
	    }
	    if(nrp->monitor_ref) {
		tup = MK_2TUP(AM_monitor, MK_UINT(nrp->monitor_ref));
		nrl = MK_CONS(tup, nrl);
	    }
	    if(nrp->ets_ref) {
		tup = MK_2TUP(AM_ets, MK_UINT(nrp->ets_ref));
		nrl = MK_CONS(tup, nrl);
	    }
	    if(nrp->bin_ref) {
		tup = MK_2TUP(AM_binary, MK_UINT(nrp->bin_ref));
		nrl = MK_CONS(tup, nrl);
	    }
	    if(nrp->timer_ref) {
		tup = MK_2TUP(AM_timer, MK_UINT(nrp->timer_ref));
		nrl = MK_CONS(tup, nrl);
	    }
	    if(nrp->system_ref) {
		tup = MK_2TUP(AM_system, MK_UINT(nrp->system_ref));
		nrl = MK_CONS(tup, nrl);
	    }

	    nrid = nrp->id;
	    if (!IS_CONST(nrp->id)) {

		Uint nrid_sz = size_object(nrp->id);
		if (szp)
		    *szp += nrid_sz;
		if (hpp)
		    nrid = copy_struct(nrp->id, nrid_sz, hpp, NULL);
	    }

	    if (is_internal_pid(nrid) || nrid == am_error_logger) {
		ASSERT(!nrp->ets_ref && !nrp->bin_ref && !nrp->system_ref);
		tup = MK_2TUP(AM_process, nrid);
	    }
	    else if (is_tuple(nrid)) {
		Eterm *t;
		ASSERT(!nrp->ets_ref && !nrp->bin_ref);
		t = tuple_val(nrid);
		ASSERT(2 == arityval(t[0]));
		tup = MK_2TUP(t[1], t[2]);
	    }
	    else if(is_internal_port(nrid)) {
		ASSERT(!nrp->heap_ref && !nrp->ets_ref && !nrp->bin_ref
		       && !nrp->timer_ref && !nrp->system_ref);
		tup = MK_2TUP(AM_port, nrid);
	    }
	    else if(nrp->ets_ref) {
		ASSERT(!nrp->heap_ref && !nrp->link_ref && 
		       !nrp->monitor_ref && !nrp->bin_ref
		       && !nrp->timer_ref && !nrp->system_ref);
		tup = MK_2TUP(AM_ets, nrid);
	    }
	    else if(nrp->bin_ref) {
		ASSERT(is_small(nrid) || is_big(nrid));
		ASSERT(!nrp->heap_ref && !nrp->ets_ref && !nrp->link_ref && 
		       !nrp->monitor_ref && !nrp->timer_ref
		       && !nrp->system_ref);
		tup = MK_2TUP(AM_match_spec, nrid);
	    }
	    else  {
		ASSERT(!nrp->heap_ref && !nrp->ets_ref && !nrp->bin_ref);
		ASSERT(is_atom(nrid));
		tup = MK_2TUP(AM_dist, nrid);
	    }
	    tup = MK_2TUP(tup, nrl);
	    /* NodeReferenceIdList = [{{ReferrerType, ID}, NodeReferenceList}] */
	    nril = MK_CONS(tup, nril);
	}

	/* NodeList = [{{Node, Creation}, Refc, NodeReferenceIdList}] */

	tup = MK_2TUP(referred_nodes[i].node->sysname,
		      MK_UINT(referred_nodes[i].node->creation));
	tup = MK_3TUP(tup, MK_UINT(erts_refc_read(&referred_nodes[i].node->refc, 1)), nril);
	nl = MK_CONS(tup, nl);
    }

    for(i = 0; i < no_referred_dists; i++) {
	DistReferrer *drp;
	Eterm dril = NIL;
	for(drp = referred_dists[i].referrers; drp; drp = drp->next) {
	    Eterm drl = NIL;

	    /* DistReferenceList = [{ReferenceType,References}] */
	    if(drp->node_ref) {
		tup = MK_2TUP(AM_node, MK_UINT(drp->node_ref));
		drl = MK_CONS(tup, drl);
	    }
	    if(drp->ctrl_ref) {
		tup = MK_2TUP(AM_control, MK_UINT(drp->ctrl_ref));
		drl = MK_CONS(tup, drl);
	    }
	    if(drp->heap_ref) {
		tup = MK_2TUP(AM_heap, MK_UINT(drp->heap_ref));
		drl = MK_CONS(tup, drl);
	    }

	    if (is_internal_pid(drp->id)) {
		ASSERT(!drp->node_ref);
		tup = MK_2TUP(AM_process, drp->id);
	    }
	    else if(is_internal_port(drp->id)) {
		ASSERT(drp->ctrl_ref && !drp->node_ref);
		tup = MK_2TUP(AM_port, drp->id);
	    }
	    else {
		ASSERT(!drp->ctrl_ref && drp->node_ref);
		ASSERT(is_atom(drp->id));
		tup = MK_2TUP(drp->id, MK_UINT(drp->creation));
		tup = MK_2TUP(AM_node, tup);
	    }

	    tup = MK_2TUP(tup, drl);

	    /* DistReferenceIdList =
	       [{{ReferrerType, ID}, DistReferenceList}] */
	    dril = MK_CONS(tup, dril);

	}

	/* DistList = [{Dist, Refc, ReferenceIdList}] */
	tup = MK_3TUP(referred_dists[i].dist->sysname,
		      MK_UINT(erts_refc_read(&referred_dists[i].dist->refc, 1)),
		      dril);
	dl = MK_CONS(tup, dl);
    }

    /* {{node_references, NodeList}, {dist_references, DistList}} */

    tup = MK_2TUP(AM_node_references, nl);
    tup2 = MK_2TUP(AM_dist_references, dl);
    tup = MK_2TUP(tup, tup2);

    return tup;
#undef  MK_2TUP
#undef  MK_3TUP
#undef  MK_CONS
#undef  MK_UINT

}

static void
delete_reference_table(void)
{
    Uint i;
    for(i = 0; i < no_referred_nodes; i++) {
	NodeReferrer *nrp;
	NodeReferrer *tnrp;
	nrp = referred_nodes[i].referrers;
	while(nrp) {
	    tnrp = nrp;
	    nrp = nrp->next;
	    erts_free(ERTS_ALC_T_NC_TMP, (void *) tnrp);
	}
    }
    if (referred_nodes)
	erts_free(ERTS_ALC_T_NC_TMP, (void *) referred_nodes);

    for(i = 0; i < no_referred_dists; i++) {
	DistReferrer *drp;
	DistReferrer *tdrp;
	drp = referred_dists[i].referrers;
	while(drp) {
	    tdrp = drp;
	    drp = drp->next;
	    erts_free(ERTS_ALC_T_NC_TMP, (void *) tdrp);
	}
    }
    if (referred_dists)
	erts_free(ERTS_ALC_T_NC_TMP, (void *) referred_dists);
    while(inserted_bins) {
	InsertedBin *ib = inserted_bins;
	inserted_bins = inserted_bins->next;
	erts_free(ERTS_ALC_T_NC_TMP, (void *)ib);
    }
}