aboutsummaryrefslogblamecommitdiffstats
path: root/lib/kernel/src/global_group.erl
blob: 025a9b8a5bc741fd2e688961d82e0adc3adc20d9 (plain) (tree)
1
2
3
4
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
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

                   
                                                        


























































                                                                                       


                                                            






























                                                                                       

                                                                 

                           
                                      





                                                
                                




                                                            

                                           

                                     

                                                             

                               


                                                                    

                                      
                                                    

                                  

                                                           




















                                                     






                                                                  















































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                              
                                           


















                                                                      
                                                       

                                                                  
                                                             




















































































































































































































































































































                                                                                                                                   
%%
%% %CopyrightBegin%
%% 
%% Copyright Ericsson AB 1998-2011. 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%
%%
-module(global_group).

%% Groups nodes into global groups with an own global name space.

-behaviour(gen_server).

%% External exports
-export([start/0, start_link/0, stop/0, init/1]).
-export([handle_call/3, handle_cast/2, handle_info/2, 
	 terminate/2, code_change/3]).

-export([global_groups/0]).
-export([monitor_nodes/1]).
-export([own_nodes/0]).
-export([registered_names/1]).
-export([send/2]).
-export([send/3]).
-export([whereis_name/1]).
-export([whereis_name/2]).
-export([global_groups_changed/1]).
-export([global_groups_added/1]).
-export([global_groups_removed/1]).
-export([sync/0]).
-export([ng_add_check/2, ng_add_check/3]).

-export([info/0]).
-export([registered_names_test/1]).
-export([send_test/2]).
-export([whereis_name_test/1]).
-export([get_own_nodes/0, get_own_nodes_with_errors/0]).
-export([publish_on_nodes/0]).

-export([config_scan/1, config_scan/2]).

%% Internal exports
-export([sync_init/4]).


-define(cc_vsn, 2).

%%%====================================================================================

-type publish_type() :: 'hidden' | 'normal'.
-type sync_state()   :: 'no_conf' | 'synced'.

-type group_name()  :: atom().
-type group_tuple() :: {GroupName :: group_name(), [node()]}
                     | {GroupName :: group_name(),
                        PublishType :: publish_type(),
                        [node()]}.

%%%====================================================================================
%%% The state of the global_group process
%%% 
%%% sync_state =  no_conf (global_groups not defined, inital state) |
%%%               synced 
%%% group_name =  Own global group name
%%% nodes =       Nodes in the own global group
%%% no_contact =  Nodes which we haven't had contact with yet
%%% sync_error =  Nodes which we haven't had contact with yet
%%% other_grps =  list of other global group names and nodes, [{otherName, [Node]}]
%%% node_name =   Own node 
%%% monitor =     List of Pids requesting nodeup/nodedown
%%%====================================================================================

-record(state, {sync_state = no_conf        :: sync_state(),
		connect_all                 :: boolean(),
		group_name = []             :: group_name() | [],
		nodes = []                  :: [node()],
		no_contact = []             :: [node()],
		sync_error = [],
		other_grps = [], 
		node_name = node()          :: node(),
		monitor = [],
		publish_type = normal       :: publish_type(),
		group_publish_type = normal :: publish_type()}).


%%%====================================================================================
%%% External exported
%%%====================================================================================

-spec global_groups() -> {GroupName, GroupNames} | undefined when
      GroupName :: group_name(),
      GroupNames :: [GroupName].
global_groups() ->
    request(global_groups).

-spec monitor_nodes(Flag) -> 'ok' when
      Flag :: boolean().
monitor_nodes(Flag) -> 
    case Flag of
	true -> request({monitor_nodes, Flag});
	false -> request({monitor_nodes, Flag});
	_ -> {error, not_boolean}
    end.

-spec own_nodes() -> Nodes when
      Nodes :: [Node :: node()].
own_nodes() ->
    request(own_nodes).

-type name()  :: atom().
-type where() :: {'node', node()} | {'group', group_name()}.

-spec registered_names(Where) -> Names when
      Where :: where(),
      Names :: [Name :: name()].
registered_names(Arg) ->
    request({registered_names, Arg}).

-spec send(Name, Msg) -> pid() | {'badarg', {Name, Msg}} when
      Name :: name(),
      Msg :: term().
send(Name, Msg) ->
    request({send, Name, Msg}).

-spec send(Where, Name, Msg) -> pid() | {'badarg', {Name, Msg}} when
      Where :: where(),
      Name :: name(),
      Msg :: term().
send(Group, Name, Msg) ->
    request({send, Group, Name, Msg}).

-spec whereis_name(Name) -> pid() | 'undefined' when
      Name :: name().
whereis_name(Name) ->
    request({whereis_name, Name}).

-spec whereis_name(Where, Name) -> pid() | 'undefined' when
      Where :: where(),
      Name :: name().
whereis_name(Group, Name) ->
    request({whereis_name, Group, Name}).

global_groups_changed(NewPara) ->
    request({global_groups_changed, NewPara}).

global_groups_added(NewPara) ->
    request({global_groups_added, NewPara}).

global_groups_removed(NewPara) ->
    request({global_groups_removed, NewPara}).

-spec sync() -> 'ok'.
sync() ->
    request(sync).

ng_add_check(Node, OthersNG) ->
    ng_add_check(Node, normal, OthersNG).

ng_add_check(Node, PubType, OthersNG) ->
    request({ng_add_check, Node, PubType, OthersNG}).

-type info_item() :: {'state', State :: sync_state()}
                   | {'own_group_name', GroupName :: group_name()}
                   | {'own_group_nodes', Nodes :: [node()]}
                   | {'synched_nodes', Nodes :: [node()]}
                   | {'sync_error', Nodes :: [node()]}
                   | {'no_contact', Nodes :: [node()]}
                   | {'other_groups', Groups :: [group_tuple()]}
                   | {'monitoring', Pids :: [pid()]}.

-spec info() -> [info_item()].
info() ->
    request(info, 3000).

%% ==== ONLY for test suites ====
registered_names_test(Arg) ->
    request({registered_names_test, Arg}).
send_test(Name, Msg) ->
    request({send_test, Name, Msg}).
whereis_name_test(Name) ->
    request({whereis_name_test, Name}).
%% ==== ONLY for test suites ====


request(Req) ->
    request(Req, infinity).

request(Req, Time) ->
    case whereis(global_group) of
	P when is_pid(P) ->
	    gen_server:call(global_group, Req, Time);
	_Other -> 
	    {error, global_group_not_runnig}
    end.

%%%====================================================================================
%%% gen_server start
%%%
%%% The first thing to happen is to read if the global_groups key is defined in the
%%% .config file. If not defined, the whole system is started as one global_group, 
%%% and the services of global_group are superfluous.
%%% Otherwise a sync process is started to check that all nodes in the own global
%%% group have the same configuration. This is done by sending 'conf_check' to all
%%% other nodes and requiring 'conf_check_result' back.
%%% If the nodes are not in agreement of the configuration the global_group process 
%%% will remove these nodes from the #state.nodes list. This can be a normal case
%%% at release upgrade when all nodes are not yet upgraded.
%%%
%%% It is possible to manually force a sync of the global_group. This is done for 
%%% instance after a release upgrade, after all nodes in the group beeing upgraded.
%%% The nodes are not synced automatically because it would cause the node to be
%%% disconnected from those not yet beeing upgraded.
%%%
%%% The three process dictionary variables (registered_names, send, and whereis_name) 
%%% are used to store information needed if the search process crashes. 
%%% The search process is a help process to find registered names in the system.
%%%====================================================================================
start() -> gen_server:start({local, global_group}, global_group, [], []).
start_link() -> gen_server:start_link({local, global_group}, global_group,[],[]).
stop() -> gen_server:call(global_group, stop, infinity).

init([]) ->
    process_flag(priority, max),
    ok = net_kernel:monitor_nodes(true),
    put(registered_names, [undefined]),
    put(send, [undefined]),
    put(whereis_name, [undefined]),
    process_flag(trap_exit, true),
    Ca = case init:get_argument(connect_all) of
	     {ok, [["false"]]} ->
		 false;
	     _ ->
		 true
	 end,
    PT = publish_arg(),
    case application:get_env(kernel, global_groups) of
	undefined ->
	    update_publish_nodes(PT),
	    {ok, #state{publish_type = PT,
			connect_all = Ca}};
	{ok, []} ->
	    update_publish_nodes(PT),
	    {ok, #state{publish_type = PT,
			connect_all = Ca}};
	{ok, NodeGrps} ->
	    {DefGroupName, PubTpGrp, DefNodes, DefOther} = 
		case catch config_scan(NodeGrps, publish_type) of
		    {error, _Error2} ->
			update_publish_nodes(PT),
			exit({error, {'invalid global_groups definition', NodeGrps}});
		    {DefGroupNameT, PubType, DefNodesT, DefOtherT} ->
			update_publish_nodes(PT, {PubType, DefNodesT}),
			%% First disconnect any nodes not belonging to our own group
			disconnect_nodes(nodes(connected) -- DefNodesT),
			lists:foreach(fun(Node) ->
					      erlang:monitor_node(Node, true)
				      end,
				      DefNodesT),
			{DefGroupNameT, PubType, lists:delete(node(), DefNodesT), DefOtherT}
		end,
	    {ok, #state{publish_type = PT, group_publish_type = PubTpGrp,
			sync_state = synced, group_name = DefGroupName, 
			no_contact = lists:sort(DefNodes), 
			other_grps = DefOther}}
    end.


%%%====================================================================================
%%% sync() -> ok 
%%%
%%% An operator ordered sync of the own global group. This must be done after
%%% a release upgrade. It can also be ordered if somthing has made the nodes
%%% to disagree of the global_groups definition.
%%%====================================================================================
handle_call(sync, _From, S) ->
%    io:format("~p sync ~p~n",[node(), application:get_env(kernel, global_groups)]),
    case application:get_env(kernel, global_groups) of
	undefined ->
	    update_publish_nodes(S#state.publish_type),
	    {reply, ok, S};
	{ok, []} ->
	    update_publish_nodes(S#state.publish_type),
	    {reply, ok, S};
	{ok, NodeGrps} ->
	    {DefGroupName, PubTpGrp, DefNodes, DefOther} = 
		case catch config_scan(NodeGrps, publish_type) of
		    {error, _Error2} ->
			exit({error, {'invalid global_groups definition', NodeGrps}});
		    {DefGroupNameT, PubType, DefNodesT, DefOtherT} ->
			update_publish_nodes(S#state.publish_type, {PubType, DefNodesT}),
			%% First inform global on all nodes not belonging to our own group
			disconnect_nodes(nodes(connected) -- DefNodesT),
			%% Sync with the nodes in the own group
			kill_global_group_check(),
			Pid = spawn_link(?MODULE, sync_init, 
					 [sync, DefGroupNameT, PubType, DefNodesT]),
			register(global_group_check, Pid),
			{DefGroupNameT, PubType, lists:delete(node(), DefNodesT), DefOtherT}
		end,
	    {reply, ok, S#state{sync_state = synced, group_name = DefGroupName, 
				no_contact = lists:sort(DefNodes), 
				other_grps = DefOther, group_publish_type = PubTpGrp}}
    end;



%%%====================================================================================
%%% global_groups() -> {OwnGroupName, [OtherGroupName]} | undefined
%%%
%%% Get the names of the global groups
%%%====================================================================================
handle_call(global_groups, _From, S) ->
    Result = case S#state.sync_state of
		 no_conf ->
		     undefined;
		 synced ->
		     Other = lists:foldl(fun({N,_L}, Acc) -> Acc ++ [N]
					 end,
					 [], S#state.other_grps),
		     {S#state.group_name, Other}
	     end,
    {reply, Result, S};



%%%====================================================================================
%%% monitor_nodes(bool()) -> ok 
%%%
%%% Monitor nodes in the own global group. 
%%%   True => send nodeup/nodedown to the requesting Pid
%%%   False => stop sending nodeup/nodedown to the requesting Pid
%%%====================================================================================
handle_call({monitor_nodes, Flag}, {Pid, _}, StateIn) ->
%    io:format("***** handle_call ~p~n",[monitor_nodes]),
    {Res, State} = monitor_nodes(Flag, Pid, StateIn),
    {reply, Res, State};


%%%====================================================================================
%%% own_nodes() -> [Node] 
%%%
%%% Get a list of nodes in the own global group
%%%====================================================================================
handle_call(own_nodes, _From, S) ->
    Nodes = case S#state.sync_state of
		no_conf ->
		    [node() | nodes()];
		synced ->
		    get_own_nodes()
%		    S#state.nodes
	    end,
    {reply, Nodes, S};



%%%====================================================================================
%%% registered_names({node, Node}) -> [Name] | {error, ErrorMessage}
%%% registered_names({group, GlobalGroupName}) -> [Name] | {error, ErrorMessage}
%%%
%%% Get the registered names from a specified Node, or GlobalGroupName.
%%%====================================================================================
handle_call({registered_names, {group, Group}}, _From, S) when Group =:= S#state.group_name ->
    Res = global:registered_names(),
    {reply, Res, S};
handle_call({registered_names, {group, Group}}, From, S) ->
    case lists:keysearch(Group, 1, S#state.other_grps) of
	false ->
	    {reply, [], S};
	{value, {Group, []}} ->
	    {reply, [], S};
	{value, {Group, Nodes}} ->
	    Pid = global_search:start(names, {group, Nodes, From}),
	    Wait = get(registered_names),
	    put(registered_names, [{Pid, From} | Wait]),
	    {noreply, S}
    end;
handle_call({registered_names, {node, Node}}, _From, S) when Node =:= node() ->
    Res = global:registered_names(),
    {reply, Res, S};
handle_call({registered_names, {node, Node}}, From, S) ->
    Pid = global_search:start(names, {node, Node, From}),
%    io:format(">>>>> registered_names Pid ~p~n",[Pid]),
    Wait = get(registered_names),
    put(registered_names, [{Pid, From} | Wait]),
    {noreply, S};



%%%====================================================================================
%%% send(Name, Msg) -> Pid | {badarg, {Name, Msg}}
%%% send({node, Node}, Name, Msg) -> Pid | {badarg, {Name, Msg}}
%%% send({group, GlobalGroupName}, Name, Msg) -> Pid | {badarg, {Name, Msg}}
%%%
%%% Send the Msg to the specified globally registered Name in own global group,
%%% in specified Node, or GlobalGroupName.
%%% But first the receiver is to be found, the thread is continued at
%%% handle_cast(send_res)
%%%====================================================================================
%% Search in the whole known world, but check own node first.
handle_call({send, Name, Msg}, From, S) ->
    case global:whereis_name(Name) of
	undefined ->
	    Pid = global_search:start(send, {any, S#state.other_grps, Name, Msg, From}),
	    Wait = get(send),
	    put(send, [{Pid, From, Name, Msg} | Wait]),
	    {noreply, S};
	Found ->
	    Found ! Msg,
	    {reply, Found, S}
    end;
%% Search in the specified global group, which happens to be the own group.
handle_call({send, {group, Grp}, Name, Msg}, _From, S) when Grp =:= S#state.group_name ->
    case global:whereis_name(Name) of
	undefined ->
	    {reply, {badarg, {Name, Msg}}, S};
	Pid ->
	    Pid ! Msg,
	    {reply, Pid, S}
    end;
%% Search in the specified global group.
handle_call({send, {group, Group}, Name, Msg}, From, S) ->
    case lists:keysearch(Group, 1, S#state.other_grps) of
	false ->
	    {reply, {badarg, {Name, Msg}}, S};
	{value, {Group, []}} ->
	    {reply, {badarg, {Name, Msg}}, S};
	{value, {Group, Nodes}} ->
	    Pid = global_search:start(send, {group, Nodes, Name, Msg, From}),
	    Wait = get(send),
	    put(send, [{Pid, From, Name, Msg} | Wait]),
	    {noreply, S}
    end;
%% Search on the specified node.
handle_call({send, {node, Node}, Name, Msg}, From, S) ->
    Pid = global_search:start(send, {node, Node, Name, Msg, From}),
    Wait = get(send),
    put(send, [{Pid, From, Name, Msg} | Wait]),
    {noreply, S};



%%%====================================================================================
%%% whereis_name(Name) -> Pid | undefined
%%% whereis_name({node, Node}, Name) -> Pid | undefined
%%% whereis_name({group, GlobalGroupName}, Name) -> Pid | undefined
%%%
%%% Get the Pid of a globally registered Name in own global group,
%%% in specified Node, or GlobalGroupName.
%%% But first the process is to be found, 
%%% the thread is continued at handle_cast(find_name_res)
%%%====================================================================================
%% Search in the whole known world, but check own node first.
handle_call({whereis_name, Name}, From, S) ->
    case global:whereis_name(Name) of
	undefined ->
	    Pid = global_search:start(whereis, {any, S#state.other_grps, Name, From}),
	    Wait = get(whereis_name),
	    put(whereis_name, [{Pid, From} | Wait]),
	    {noreply, S};
	Found ->
	    {reply, Found, S}
    end;
%% Search in the specified global group, which happens to be the own group.
handle_call({whereis_name, {group, Group}, Name}, _From, S) 
  when Group =:= S#state.group_name ->
    Res = global:whereis_name(Name),
    {reply, Res, S};
%% Search in the specified global group.
handle_call({whereis_name, {group, Group}, Name}, From, S) ->
    case lists:keysearch(Group, 1, S#state.other_grps) of
	false ->
	    {reply, undefined, S};
	{value, {Group, []}} ->
	    {reply, undefined, S};
	{value, {Group, Nodes}} ->
	    Pid = global_search:start(whereis, {group, Nodes, Name, From}),
	    Wait = get(whereis_name),
	    put(whereis_name, [{Pid, From} | Wait]),
	    {noreply, S}
    end;
%% Search on the specified node.
handle_call({whereis_name, {node, Node}, Name}, From, S) ->
    Pid = global_search:start(whereis, {node, Node, Name, From}),
    Wait = get(whereis_name),
    put(whereis_name, [{Pid, From} | Wait]),
    {noreply, S};


%%%====================================================================================
%%% global_groups parameter changed
%%% The node is not resynced automatically because it would cause this node to
%%% be disconnected from those nodes not yet been upgraded.
%%%====================================================================================
handle_call({global_groups_changed, NewPara}, _From, S) ->
    {NewGroupName, PubTpGrp, NewNodes, NewOther} = 
	case catch config_scan(NewPara, publish_type) of
	    {error, _Error2} ->
		exit({error, {'invalid global_groups definition', NewPara}});
	    {DefGroupName, PubType, DefNodes, DefOther} ->
		update_publish_nodes(S#state.publish_type, {PubType, DefNodes}),
		{DefGroupName, PubType, DefNodes, DefOther}
	end,

    %% #state.nodes is the common denominator of previous and new definition
    NN = NewNodes -- (NewNodes -- S#state.nodes),
    %% rest of the nodes in the new definition are marked as not yet contacted
    NNC = (NewNodes -- S#state.nodes) --  S#state.sync_error,
    %% remove sync_error nodes not belonging to the new group
    NSE = NewNodes -- (NewNodes -- S#state.sync_error),

    %% Disconnect the connection to nodes which are not in our old global group.
    %% This is done because if we already are aware of new nodes (to our global
    %% group) global is not going to be synced to these nodes. We disconnect instead
    %% of connect because upgrades can be done node by node and we cannot really
    %% know what nodes these new nodes are synced to. The operator can always 
    %% manually force a sync of the nodes after all nodes beeing uppgraded.
    %% We must disconnect also if some nodes to which we have a connection
    %% will not be in any global group at all.
    force_nodedown(nodes(connected) -- NewNodes),

    NewS = S#state{group_name = NewGroupName, 
		   nodes = lists:sort(NN), 
		   no_contact = lists:sort(lists:delete(node(), NNC)), 
		   sync_error = lists:sort(NSE), 
		   other_grps = NewOther,
		   group_publish_type = PubTpGrp},
    {reply, ok, NewS};


%%%====================================================================================
%%% global_groups parameter added
%%% The node is not resynced automatically because it would cause this node to
%%% be disconnected from those nodes not yet been upgraded.
%%%====================================================================================
handle_call({global_groups_added, NewPara}, _From, S) ->
%    io:format("### global_groups_changed, NewPara ~p ~n",[NewPara]),
    {NewGroupName, PubTpGrp, NewNodes, NewOther} = 
	case catch config_scan(NewPara, publish_type) of
	    {error, _Error2} ->
		exit({error, {'invalid global_groups definition', NewPara}});
	    {DefGroupName, PubType, DefNodes, DefOther} ->
		update_publish_nodes(S#state.publish_type, {PubType, DefNodes}),
		{DefGroupName, PubType, DefNodes, DefOther}
	end,

    %% disconnect from those nodes which are not going to be in our global group
    force_nodedown(nodes(connected) -- NewNodes),

    %% Check which nodes are already updated
    OwnNG = get_own_nodes(),
    NGACArgs = case S#state.group_publish_type of
		   normal ->
		       [node(), OwnNG];
		   _ ->
		       [node(), S#state.group_publish_type, OwnNG]
	       end,
    {NN, NNC, NSE} = 
	lists:foldl(fun(Node, {NN_acc, NNC_acc, NSE_acc}) -> 
			    case rpc:call(Node, global_group, ng_add_check, NGACArgs) of
				{badrpc, _} ->
				    {NN_acc, [Node | NNC_acc], NSE_acc};
				agreed ->
				    {[Node | NN_acc], NNC_acc, NSE_acc};
				not_agreed ->
				    {NN_acc, NNC_acc, [Node | NSE_acc]}
			    end
		    end,
		    {[], [], []}, lists:delete(node(), NewNodes)),
    NewS = S#state{sync_state = synced, group_name = NewGroupName, nodes = lists:sort(NN), 
		   sync_error = lists:sort(NSE), no_contact = lists:sort(NNC), 
		   other_grps = NewOther, group_publish_type = PubTpGrp},
    {reply, ok, NewS};


%%%====================================================================================
%%% global_groups parameter removed
%%%====================================================================================
handle_call({global_groups_removed, _NewPara}, _From, S) ->
%    io:format("### global_groups_removed, NewPara ~p ~n",[_NewPara]),
    update_publish_nodes(S#state.publish_type),
    NewS = S#state{sync_state = no_conf, group_name = [], nodes = [], 
		   sync_error = [], no_contact = [], 
		   other_grps = []},
    {reply, ok, NewS};


%%%====================================================================================
%%% global_groups parameter added to some other node which thinks that we
%%% belong to the same global group.
%%% It could happen that our node is not yet updated with the new node_group parameter
%%%====================================================================================
handle_call({ng_add_check, Node, PubType, OthersNG}, _From, S) ->
    %% Check which nodes are already updated
    OwnNG = get_own_nodes(),
    case S#state.group_publish_type =:= PubType of
	true ->
	    case OwnNG of
		OthersNG ->
		    NN = [Node | S#state.nodes],
		    NSE = lists:delete(Node, S#state.sync_error),
		    NNC = lists:delete(Node, S#state.no_contact),
		    NewS = S#state{nodes = lists:sort(NN), 
				   sync_error = NSE, 
				   no_contact = NNC},
		    {reply, agreed, NewS};
		_ ->
		    {reply, not_agreed, S}
	    end;
	_ ->
	    {reply, not_agreed, S}
    end;



%%%====================================================================================
%%% Misceleaneous help function to read some variables
%%%====================================================================================
handle_call(info, _From, S) ->    
    Reply = [{state,          S#state.sync_state},
	     {own_group_name, S#state.group_name},
	     {own_group_nodes, get_own_nodes()},
%	     {"nodes()",      lists:sort(nodes())},
	     {synced_nodes,   S#state.nodes},
	     {sync_error,     S#state.sync_error},
	     {no_contact,     S#state.no_contact},
	     {other_groups,   S#state.other_grps},
	     {monitoring,     S#state.monitor}],

    {reply, Reply, S};

handle_call(get, _From, S) ->
    {reply, get(), S};


%%%====================================================================================
%%% Only for test suites. These tests when the search process exits.
%%%====================================================================================
handle_call({registered_names_test, {node, 'test3844zty'}}, From, S) ->
    Pid = global_search:start(names_test, {node, 'test3844zty'}),
    Wait = get(registered_names),
    put(registered_names, [{Pid, From} | Wait]),
    {noreply, S};
handle_call({registered_names_test, {node, _Node}}, _From, S) ->
    {reply, {error, illegal_function_call}, S};
handle_call({send_test, Name, 'test3844zty'}, From, S) ->
    Pid = global_search:start(send_test, 'test3844zty'),
    Wait = get(send),
    put(send, [{Pid, From, Name, 'test3844zty'} | Wait]),
    {noreply, S};
handle_call({send_test, _Name, _Msg }, _From, S) ->
    {reply, {error, illegal_function_call}, S};
handle_call({whereis_name_test, 'test3844zty'}, From, S) ->
    Pid = global_search:start(whereis_test, 'test3844zty'),
    Wait = get(whereis_name),
    put(whereis_name, [{Pid, From} | Wait]),
    {noreply, S};
handle_call({whereis_name_test, _Name}, _From, S) ->
    {reply, {error, illegal_function_call}, S};

handle_call(Call, _From, S) ->
%    io:format("***** handle_call ~p~n",[Call]),
    {reply, {illegal_message, Call}, S}.
    




%%%====================================================================================
%%% registered_names({node, Node}) -> [Name] | {error, ErrorMessage}
%%% registered_names({group, GlobalGroupName}) -> [Name] | {error, ErrorMessage}
%%%
%%% Get a list of nodes in the own global group
%%%====================================================================================
handle_cast({registered_names, User}, S) ->
%    io:format(">>>>> registered_names User ~p~n",[User]),
    Res = global:registered_names(),
    User ! {registered_names_res, Res},
    {noreply, S};

handle_cast({registered_names_res, Result, Pid, From}, S) ->
%    io:format(">>>>> registered_names_res Result ~p~n",[Result]),
    unlink(Pid),
    exit(Pid, normal),
    Wait = get(registered_names),
    NewWait = lists:delete({Pid, From},Wait),
    put(registered_names, NewWait),
    gen_server:reply(From, Result),
    {noreply, S};



%%%====================================================================================
%%% send(Name, Msg) -> Pid | {error, ErrorMessage}
%%% send({node, Node}, Name, Msg) -> Pid | {error, ErrorMessage}
%%% send({group, GlobalGroupName}, Name, Msg) -> Pid | {error, ErrorMessage}
%%%
%%% The registered Name is found; send the message to it, kill the search process,
%%% and return to the requesting process.
%%%====================================================================================
handle_cast({send_res, Result, Name, Msg, Pid, From}, S) ->
%    io:format("~p>>>>> send_res Result ~p~n",[node(), Result]),
    case Result of
	{badarg,{Name, Msg}} ->
	    continue;
	ToPid ->
	    ToPid ! Msg
    end,
    unlink(Pid),
    exit(Pid, normal),
    Wait = get(send),
    NewWait = lists:delete({Pid, From, Name, Msg},Wait),
    put(send, NewWait),
    gen_server:reply(From, Result),
    {noreply, S};



%%%====================================================================================
%%% A request from a search process to check if this Name is registered at this node.
%%%====================================================================================
handle_cast({find_name, User, Name}, S) ->
    Res = global:whereis_name(Name),
%    io:format(">>>>> find_name Name ~p   Res ~p~n",[Name, Res]),
    User ! {find_name_res, Res},
    {noreply, S};

%%%====================================================================================
%%% whereis_name(Name) -> Pid | undefined
%%% whereis_name({node, Node}, Name) -> Pid | undefined
%%% whereis_name({group, GlobalGroupName}, Name) -> Pid | undefined
%%%
%%% The registered Name is found; kill the search process
%%% and return to the requesting process.
%%%====================================================================================
handle_cast({find_name_res, Result, Pid, From}, S) ->
%    io:format(">>>>> find_name_res Result ~p~n",[Result]),
%    io:format(">>>>> find_name_res get() ~p~n",[get()]),
    unlink(Pid),
    exit(Pid, normal),
    Wait = get(whereis_name),
    NewWait = lists:delete({Pid, From},Wait),
    put(whereis_name, NewWait),
    gen_server:reply(From, Result),
    {noreply, S};


%%%====================================================================================
%%% The node is synced successfully
%%%====================================================================================
handle_cast({synced, NoContact}, S) ->
%    io:format("~p>>>>> synced ~p  ~n",[node(), NoContact]),
    kill_global_group_check(),
    Nodes = get_own_nodes() -- [node() | NoContact],
    {noreply, S#state{nodes = lists:sort(Nodes),
		      sync_error = [],
		      no_contact = NoContact}};    


%%%====================================================================================
%%% The node could not sync with some other nodes.
%%%====================================================================================
handle_cast({sync_error, NoContact, ErrorNodes}, S) ->
%    io:format("~p>>>>> sync_error ~p ~p ~n",[node(), NoContact, ErrorNodes]),
    Txt = io_lib:format("Global group: Could not synchronize with these nodes ~p~n"
			"because global_groups were not in agreement. ~n", [ErrorNodes]),
    error_logger:error_report(Txt),
    kill_global_group_check(),
    Nodes = (get_own_nodes() -- [node() | NoContact]) -- ErrorNodes,
    {noreply, S#state{nodes = lists:sort(Nodes), 
		      sync_error = ErrorNodes,
		      no_contact = NoContact}};


%%%====================================================================================
%%% Another node is checking this node's group configuration
%%%====================================================================================
handle_cast({conf_check, Vsn, Node, From, sync, CCName, CCNodes}, S) ->
    handle_cast({conf_check, Vsn, Node, From, sync, CCName, normal, CCNodes}, S);
    
handle_cast({conf_check, Vsn, Node, From, sync, CCName, PubType, CCNodes}, S) ->
    CurNodes = S#state.nodes,
%    io:format(">>>>> conf_check,sync  Node ~p~n",[Node]),
    %% Another node is syncing, 
    %% done for instance after upgrade of global_groups parameter
    NS = 
	case application:get_env(kernel, global_groups) of
	    undefined ->
		%% We didn't have any node_group definition
		update_publish_nodes(S#state.publish_type),
		disconnect_nodes([Node]),
		{global_group_check, Node} ! {config_error, Vsn, From, node()},
		S;
	    {ok, []} ->
		%% Our node_group definition was empty
		update_publish_nodes(S#state.publish_type),
		disconnect_nodes([Node]),
		{global_group_check, Node} ! {config_error, Vsn, From, node()},
		S;
	    %%---------------------------------
	    %% global_groups defined
	    %%---------------------------------
	    {ok, NodeGrps} ->
		case catch config_scan(NodeGrps, publish_type) of
		    {error, _Error2} ->
			%% Our node_group definition was erroneous
			disconnect_nodes([Node]),
			{global_group_check, Node} ! {config_error, Vsn, From, node()},
			S#state{nodes = lists:delete(Node, CurNodes)};

		    {CCName, PubType, CCNodes, _OtherDef} ->
			%% OK, add the node to the #state.nodes if it isn't there
			update_publish_nodes(S#state.publish_type, {PubType, CCNodes}),
			global_name_server ! {nodeup, Node},
			{global_group_check, Node} ! {config_ok, Vsn, From, node()},
			case lists:member(Node, CurNodes) of
			    false ->
				NewNodes = lists:sort([Node | CurNodes]),
				NSE = lists:delete(Node, S#state.sync_error),
				NNC = lists:delete(Node, S#state.no_contact),
				S#state{nodes = NewNodes, 
				        sync_error = NSE,
				        no_contact = NNC};
			    true ->
				S
			end;
		    _ ->
			%% node_group definitions were not in agreement
			disconnect_nodes([Node]),
			{global_group_check, Node} ! {config_error, Vsn, From, node()},
			NN = lists:delete(Node, S#state.nodes),
			NSE = lists:delete(Node, S#state.sync_error),
			NNC = lists:delete(Node, S#state.no_contact),
			S#state{nodes = NN,
				sync_error = NSE,
				no_contact = NNC}
		end
	end,
    {noreply, NS};


handle_cast(_Cast, S) ->
%    io:format("***** handle_cast ~p~n",[_Cast]),
    {noreply, S}.
    


%%%====================================================================================
%%% A node went down. If no global group configuration inform global;
%%% if global group configuration inform global only if the node is one in
%%% the own global group.
%%%====================================================================================
handle_info({nodeup, Node}, S) when S#state.sync_state =:= no_conf ->
%    io:format("~p>>>>> nodeup, Node ~p ~n",[node(), Node]),
    send_monitor(S#state.monitor, {nodeup, Node}, S#state.sync_state),
    global_name_server ! {nodeup, Node},
    {noreply, S};
handle_info({nodeup, Node}, S) ->
%    io:format("~p>>>>> nodeup, Node ~p ~n",[node(), Node]),
    OthersNG = case S#state.sync_state of
		   synced ->
		       X = (catch rpc:call(Node, global_group, get_own_nodes, [])),
		       case X of
			   X when is_list(X) ->
			       lists:sort(X);
			   _ ->
			       []
		       end;
		   no_conf ->
		       []
	       end,

    NNC = lists:delete(Node, S#state.no_contact),
    NSE = lists:delete(Node, S#state.sync_error),
    OwnNG = get_own_nodes(),
    case OwnNG of
	OthersNG ->
	    send_monitor(S#state.monitor, {nodeup, Node}, S#state.sync_state),
	    global_name_server ! {nodeup, Node},
	    case lists:member(Node, S#state.nodes) of
		false ->
		    NN = lists:sort([Node | S#state.nodes]),
		    {noreply, S#state{nodes = NN, 
				      no_contact = NNC,
				      sync_error = NSE}};
		true ->
		    {noreply, S#state{no_contact = NNC,
				      sync_error = NSE}}
	    end;
	_ ->
	    case {lists:member(Node, get_own_nodes()), 
		  lists:member(Node, S#state.sync_error)} of
		{true, false} ->
		    NSE2 = lists:sort([Node | S#state.sync_error]),
		    {noreply, S#state{no_contact = NNC,
				      sync_error = NSE2}};
		_ ->
		    {noreply, S}
	    end
    end;

%%%====================================================================================
%%% A node has crashed. 
%%% nodedown must always be sent to global; this is a security measurement
%%% because during release upgrade the global_groups parameter is upgraded
%%% before the node is synced. This means that nodedown may arrive from a
%%% node which we are not aware of.
%%%====================================================================================
handle_info({nodedown, Node}, S) when S#state.sync_state =:= no_conf ->
%    io:format("~p>>>>> nodedown, no_conf Node ~p~n",[node(), Node]),
    send_monitor(S#state.monitor, {nodedown, Node}, S#state.sync_state),
    global_name_server ! {nodedown, Node},
    {noreply, S};
handle_info({nodedown, Node}, S) ->
%    io:format("~p>>>>> nodedown, Node ~p  ~n",[node(), Node]),
    send_monitor(S#state.monitor, {nodedown, Node}, S#state.sync_state),
    global_name_server ! {nodedown, Node},
    NN = lists:delete(Node, S#state.nodes),
    NSE = lists:delete(Node, S#state.sync_error),
    NNC = case {lists:member(Node, get_own_nodes()), 
		lists:member(Node, S#state.no_contact)} of
	      {true, false} ->
		  [Node | S#state.no_contact];
	      _ ->
		  S#state.no_contact
	  end,
    {noreply, S#state{nodes = NN, no_contact = NNC, sync_error = NSE}};


%%%====================================================================================
%%% A node has changed its global_groups definition, and is telling us that we are not
%%% included in his group any more. This could happen at release upgrade.
%%%====================================================================================
handle_info({disconnect_node, Node}, S) ->
%    io:format("~p>>>>> disconnect_node Node ~p CN ~p~n",[node(), Node, S#state.nodes]),
    case {S#state.sync_state, lists:member(Node, S#state.nodes)} of
	{synced, true} ->
	    send_monitor(S#state.monitor, {nodedown, Node}, S#state.sync_state);
	_ ->
	    cont
    end,
    global_name_server ! {nodedown, Node}, %% nodedown is used to inform global of the
                                           %% disconnected node
    NN = lists:delete(Node, S#state.nodes),
    NNC = lists:delete(Node, S#state.no_contact),
    NSE = lists:delete(Node, S#state.sync_error),
    {noreply, S#state{nodes = NN, no_contact = NNC, sync_error = NSE}};




handle_info({'EXIT', ExitPid, Reason}, S) ->
    check_exit(ExitPid, Reason),
    {noreply, S};


handle_info(_Info, S) ->
%    io:format("***** handle_info = ~p~n",[_Info]),
    {noreply, S}.



terminate(_Reason, _S) ->
    ok.
    

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.





%%%====================================================================================
%%% Check the global group configuration.
%%%====================================================================================

config_scan(NodeGrps) ->
    config_scan(NodeGrps, original).

config_scan(NodeGrps, original) ->
    case config_scan(NodeGrps, publish_type) of
	{DefGroupName, _, DefNodes, DefOther} ->
	    {DefGroupName, DefNodes, DefOther};
	Error ->
	    Error
    end;
config_scan(NodeGrps, publish_type) ->
    config_scan(node(), normal, NodeGrps, no_name, [], []).

config_scan(_MyNode, PubType, [], Own_name, OwnNodes, OtherNodeGrps) ->
    {Own_name, PubType, lists:sort(OwnNodes), lists:reverse(OtherNodeGrps)};
config_scan(MyNode, PubType, [GrpTuple|NodeGrps], Own_name, OwnNodes, OtherNodeGrps) ->
    {Name, PubTypeGroup, Nodes} = grp_tuple(GrpTuple),
    case lists:member(MyNode, Nodes) of
	true ->
	    case Own_name of
		no_name ->
		    config_scan(MyNode, PubTypeGroup, NodeGrps, Name, Nodes, OtherNodeGrps);
		_ ->
		    {error, {'node defined twice', {Own_name, Name}}}
	    end;
	false ->
	    config_scan(MyNode,PubType,NodeGrps,Own_name,OwnNodes,
			[{Name, Nodes}|OtherNodeGrps])
    end.

grp_tuple({Name, Nodes}) ->
    {Name, normal, Nodes};
grp_tuple({Name, hidden, Nodes}) ->
    {Name, hidden, Nodes};
grp_tuple({Name, normal, Nodes}) ->
    {Name, normal, Nodes}.

    
%%%====================================================================================
%%% The special process which checks that all nodes in the own global group
%%% agrees on the configuration.
%%%====================================================================================
-spec sync_init(_, _, _, _) -> no_return().
sync_init(Type, Cname, PubType, Nodes) ->
    {Up, Down} = sync_check_node(lists:delete(node(), Nodes), [], []),
    sync_check_init(Type, Up, Cname, Nodes, Down, PubType).

sync_check_node([], Up, Down) ->
    {Up, Down};
sync_check_node([Node|Nodes], Up, Down) ->
    case net_adm:ping(Node) of
	pang ->
	    sync_check_node(Nodes, Up, [Node|Down]);
	pong ->
	    sync_check_node(Nodes, [Node|Up], Down)
    end.



%%%-------------------------------------------------------------
%%% Check that all nodes are in agreement of the global
%%% group configuration.
%%%-------------------------------------------------------------
-spec sync_check_init(_, _, _, _, _, _) -> no_return().
sync_check_init(Type, Up, Cname, Nodes, Down, PubType) ->
    sync_check_init(Type, Up, Cname, Nodes, 3, [], Down, PubType).

-spec sync_check_init(_, _, _, _, _, _, _, _) -> no_return().
sync_check_init(_Type, NoContact, _Cname, _Nodes, 0, ErrorNodes, Down, _PubType) ->
    case ErrorNodes of
	[] -> 
	    gen_server:cast(global_group, {synced, lists:sort(NoContact ++ Down)});
	_ ->
	    gen_server:cast(global_group, {sync_error, lists:sort(NoContact ++ Down),
					   ErrorNodes})
    end,
    receive
	kill ->
	    exit(normal)
    after 5000 ->
	    exit(normal)
    end;

sync_check_init(Type, Up, Cname, Nodes, N, ErrorNodes, Down, PubType) ->
    ConfCheckMsg = case PubType of
		       normal ->
			   {conf_check, ?cc_vsn, node(), self(), Type, Cname, Nodes};
		       _ ->
			   {conf_check, ?cc_vsn, node(), self(), Type, Cname, PubType, Nodes}
		   end,
    lists:foreach(fun(Node) -> 
			  gen_server:cast({global_group, Node}, ConfCheckMsg)
		  end, Up),
    case sync_check(Up) of
	{ok, synced} ->
	    sync_check_init(Type, [], Cname, Nodes, 0, ErrorNodes, Down, PubType);
	{error, NewErrorNodes} ->
	    sync_check_init(Type, [], Cname, Nodes, 0, ErrorNodes ++ NewErrorNodes, Down, PubType);
	{more, Rem, NewErrorNodes} ->
	    %% Try again to reach the global_group, 
	    %% obviously the node is up but not the global_group process.
	    sync_check_init(Type, Rem, Cname, Nodes, N-1, ErrorNodes ++ NewErrorNodes, Down, PubType)
    end.

sync_check(Up) ->
    sync_check(Up, Up, []).

sync_check([], _Up, []) ->
    {ok, synced};
sync_check([], _Up, ErrorNodes) ->
    {error, ErrorNodes};
sync_check(Rem, Up, ErrorNodes) ->
    receive
	{config_ok, ?cc_vsn, Pid, Node} when Pid =:= self() ->
	    global_name_server ! {nodeup, Node},
	    sync_check(Rem -- [Node], Up, ErrorNodes);
	{config_error, ?cc_vsn, Pid, Node} when Pid =:= self() ->
	    sync_check(Rem -- [Node], Up, [Node | ErrorNodes]);
	{no_global_group_configuration, ?cc_vsn, Pid, Node} when Pid =:= self() ->
	    sync_check(Rem -- [Node], Up, [Node | ErrorNodes]);
	%% Ignore, illegal vsn or illegal Pid
	_ ->
	    sync_check(Rem, Up, ErrorNodes)
    after 2000 ->
	    %% Try again, the previous conf_check message  
	    %% apparently disapared in the magic black hole.
	    {more, Rem, ErrorNodes}
    end.


%%%====================================================================================
%%% A process wants to toggle monitoring nodeup/nodedown from nodes.
%%%====================================================================================
monitor_nodes(true, Pid, State) ->
    link(Pid),
    Monitor = State#state.monitor,
    {ok, State#state{monitor = [Pid|Monitor]}};
monitor_nodes(false, Pid, State) ->
    Monitor = State#state.monitor,
    State1 = State#state{monitor = delete_all(Pid,Monitor)},
    do_unlink(Pid, State1),
    {ok, State1};
monitor_nodes(_, _, State) ->
    {error, State}.

delete_all(From, [From |Tail]) -> delete_all(From, Tail);
delete_all(From, [H|Tail]) ->  [H|delete_all(From, Tail)];
delete_all(_, []) -> [].

%% do unlink if we have no more references to Pid.
do_unlink(Pid, State) ->
    case lists:member(Pid, State#state.monitor) of
	true ->
	    false;
	_ ->
%	    io:format("unlink(Pid) ~p~n",[Pid]),
	    unlink(Pid)
    end.



%%%====================================================================================
%%% Send a nodeup/down messages to monitoring Pids in the own global group.
%%%====================================================================================
send_monitor([P|T], M, no_conf) -> safesend_nc(P, M), send_monitor(T, M, no_conf);
send_monitor([P|T], M, SyncState) -> safesend(P, M), send_monitor(T, M, SyncState);
send_monitor([], _, _) -> ok.

safesend(Name, {Msg, Node}) when is_atom(Name) ->
    case lists:member(Node, get_own_nodes()) of
	true ->
	    case whereis(Name) of 
		undefined ->
		    {Msg, Node};
		P when is_pid(P) ->
		    P ! {Msg, Node}
	    end;
	false ->
	    not_own_group
    end;
safesend(Pid, {Msg, Node}) -> 
    case lists:member(Node, get_own_nodes()) of
	true ->
	    Pid ! {Msg, Node};
	false ->
	    not_own_group
    end.

safesend_nc(Name, {Msg, Node}) when is_atom(Name) ->
    case whereis(Name) of 
	undefined ->
	    {Msg, Node};
	P when is_pid(P) ->
	    P ! {Msg, Node}
    end;
safesend_nc(Pid, {Msg, Node}) -> 
    Pid ! {Msg, Node}.






%%%====================================================================================
%%% Check which user is associated to the crashed process.
%%%====================================================================================
check_exit(ExitPid, Reason) ->
%    io:format("===EXIT===  ~p ~p ~n~p   ~n~p   ~n~p ~n~n",[ExitPid, Reason, get(registered_names), get(send), get(whereis_name)]),
    check_exit_reg(get(registered_names), ExitPid, Reason),
    check_exit_send(get(send), ExitPid, Reason),
    check_exit_where(get(whereis_name), ExitPid, Reason).


check_exit_reg(undefined, _ExitPid, _Reason) ->
    ok;
check_exit_reg(Reg, ExitPid, Reason) ->
    case lists:keysearch(ExitPid, 1, lists:delete(undefined, Reg)) of
	{value, {ExitPid, From}} ->
	    NewReg = lists:delete({ExitPid, From}, Reg),
	    put(registered_names, NewReg),
	    gen_server:reply(From, {error, Reason});
	false ->
	    not_found_ignored
    end.


check_exit_send(undefined, _ExitPid, _Reason) ->
    ok;
check_exit_send(Send, ExitPid, _Reason) ->
    case lists:keysearch(ExitPid, 1, lists:delete(undefined, Send)) of
	{value, {ExitPid, From, Name, Msg}} ->
	    NewSend = lists:delete({ExitPid, From, Name, Msg}, Send),
	    put(send, NewSend),
	    gen_server:reply(From, {badarg, {Name, Msg}});
	false ->
	    not_found_ignored
    end.


check_exit_where(undefined, _ExitPid, _Reason) ->
    ok;
check_exit_where(Where, ExitPid, Reason) ->
    case lists:keysearch(ExitPid, 1, lists:delete(undefined, Where)) of
	{value, {ExitPid, From}} ->
	    NewWhere = lists:delete({ExitPid, From}, Where),
	    put(whereis_name, NewWhere),
	    gen_server:reply(From, {error, Reason});
	false ->
	    not_found_ignored
    end.



%%%====================================================================================
%%% Kill any possible global_group_check processes
%%%====================================================================================
kill_global_group_check() ->
    case whereis(global_group_check) of
	undefined ->
	    ok;
	Pid ->
	    unlink(Pid),
	    global_group_check ! kill,
	    unregister(global_group_check)
    end.


%%%====================================================================================
%%% Disconnect nodes not belonging to own global_groups
%%%====================================================================================
disconnect_nodes(DisconnectNodes) ->
    lists:foreach(fun(Node) ->
			  {global_group, Node} ! {disconnect_node, node()},
			  global:node_disconnected(Node)
		  end,
		  DisconnectNodes).


%%%====================================================================================
%%% Disconnect nodes not belonging to own global_groups
%%%====================================================================================
force_nodedown(DisconnectNodes) ->
    lists:foreach(fun(Node) ->
			  erlang:disconnect_node(Node),
			  global:node_disconnected(Node)
		  end,
		  DisconnectNodes).


%%%====================================================================================
%%% Get the current global_groups definition
%%%====================================================================================
get_own_nodes_with_errors() ->
    case application:get_env(kernel, global_groups) of
	undefined ->
	    {ok, all};
	{ok, []} ->
	    {ok, all};
	{ok, NodeGrps} ->
	    case catch config_scan(NodeGrps, publish_type) of
		{error, Error} ->
		    {error, Error};
		{_, _, NodesDef, _} ->
		    {ok, lists:sort(NodesDef)}
	    end
    end.

get_own_nodes() ->
    case get_own_nodes_with_errors() of
	{ok, all} ->
	    [];
	{error, _} ->
	    [];
	{ok, Nodes} ->
	    Nodes
    end.

%%%====================================================================================
%%% -hidden command line argument
%%%====================================================================================
publish_arg() ->
    case init:get_argument(hidden) of
	{ok,[[]]} ->
	    hidden;
	{ok,[["true"]]} ->
	    hidden;
	_ ->
	    normal
    end.


%%%====================================================================================
%%% Own group publication type and nodes
%%%====================================================================================
own_group() ->
    case application:get_env(kernel, global_groups) of
	undefined ->
	    no_group;
	{ok, []} ->
	    no_group;
	{ok, NodeGrps} ->
	    case catch config_scan(NodeGrps, publish_type) of
		{error, _} ->
		    no_group;
		{_, PubTpGrp, NodesDef, _} ->
		    {PubTpGrp, NodesDef}
	    end
    end.


%%%====================================================================================
%%% Help function which computes publication list
%%%====================================================================================
publish_on_nodes(normal, no_group) ->
    all;
publish_on_nodes(hidden, no_group) ->
    [];
publish_on_nodes(normal, {normal, _}) ->
    all;
publish_on_nodes(hidden, {_, Nodes}) ->
    Nodes;
publish_on_nodes(_, {hidden, Nodes}) ->
    Nodes.

%%%====================================================================================
%%% Update net_kernels publication list
%%%====================================================================================
update_publish_nodes(PubArg) ->
    update_publish_nodes(PubArg, no_group).
update_publish_nodes(PubArg, MyGroup) ->
    net_kernel:update_publish_nodes(publish_on_nodes(PubArg, MyGroup)).


%%%====================================================================================
%%% Fetch publication list
%%%====================================================================================
publish_on_nodes() ->
    publish_on_nodes(publish_arg(), own_group()).