aboutsummaryrefslogtreecommitdiff
path: root/src/arm/arm_api.c
blob: 5fb2a811a9cefde27bbb4f361b7d2c4a0bd2e933 (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
/*
     This file is part of GNUnet.
     Copyright (C) 2009, 2010, 2012, 2013 GNUnet e.V.

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/

/**
 * @file arm/arm_api.c
 * @brief API for accessing the ARM service
 * @author Christian Grothoff
 * @author LRN
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_arm_service.h"
#include "gnunet_protocols.h"
#include "arm.h"

#define LOG(kind,...) GNUNET_log_from (kind, "arm-api",__VA_ARGS__)

/**
 * Handle for interacting with ARM.
 */
struct GNUNET_ARM_Handle
{
  /**
   * Our control connection to the ARM service.
   */
  struct GNUNET_CLIENT_Connection *client;

  /**
   * The configuration that we are using.
   */
  struct GNUNET_CONFIGURATION_Handle *cfg;

  /**
   * Handle for our current transmission request.
   */
  struct GNUNET_CLIENT_TransmitHandle *cth;

  /**
   * Head of doubly-linked list of pending requests.
   */
  struct ARMControlMessage *control_pending_head;

  /**
   * Tail of doubly-linked list of pending requests.
   */
  struct ARMControlMessage *control_pending_tail;

  /**
   * Head of doubly-linked list of sent requests.
   */
  struct ARMControlMessage *control_sent_head;

  /**
   * Tail of doubly-linked list of sent requests.
   */
  struct ARMControlMessage *control_sent_tail;

  /**
   * Callback to invoke on connection/disconnection.
   */
  GNUNET_ARM_ConnectionStatusCallback conn_status;

  /**
   * Closure for conn_status.
   */
  void *conn_status_cls;

  /**
   * ARM control message for the 'arm_termination_handler'
   * with the continuation to call once the ARM shutdown is done.
   */
  struct ARMControlMessage *thm;

  /**
   * ID of the reconnect task (if any).
   */
  struct GNUNET_SCHEDULER_Task *reconnect_task;

  /**
   * Current delay we use for re-trying to connect to core.
   */
  struct GNUNET_TIME_Relative retry_backoff;

  /**
   * Counter for request identifiers
   */
  uint64_t request_id_counter;

  /**
   * Are we currently disconnected and hence unable to send?
   */
  unsigned char currently_down;

  /**
   * #GNUNET_YES if we're running a service test.
   */
  unsigned char service_test_is_active;
};


/**
 * Entry in a doubly-linked list of control messages to be transmitted
 * to the arm service.
 *
 * The actual message is allocated at the end of this struct.
 */
struct ARMControlMessage
{
  /**
   * This is a doubly-linked list.
   */
  struct ARMControlMessage *next;

  /**
   * This is a doubly-linked list.
   */
  struct ARMControlMessage *prev;

  /**
   * ARM handle.
   */
  struct GNUNET_ARM_Handle *h;

  /**
   * Message to send.
   */
  struct GNUNET_ARM_Message *msg;

  /**
   * Callback for service state change requests.
   */
  GNUNET_ARM_ResultCallback result_cont;

  /**
   * Callback for service list requests.
   */
  GNUNET_ARM_ServiceListCallback list_cont;

  /**
   * Closure for @e result_cont' or @e list_cont'.
   */
  void *cont_cls;

  /**
   * Timeout for the operation.
   */
  struct GNUNET_TIME_Absolute timeout;

  /**
   * Task to run when request times out.
   */
  struct GNUNET_SCHEDULER_Task * timeout_task_id;

  /**
   * Flags for passing std descriptors to ARM (when starting ARM).
   */
  enum GNUNET_OS_InheritStdioFlags std_inheritance;

  /**
   * Type of the request expressed as a message type (start, stop or list).
   */
  uint16_t type;
};


/**
 * Connect to arm.
 *
 * @param h arm handle
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
 */
static int
reconnect_arm (struct GNUNET_ARM_Handle *h);


/**
 * Check the list of pending requests, send the next
 * one to the arm.
 *
 * @param h arm handle
 * @param ignore_currently_down transmit message even if not initialized?
 */
static void
trigger_next_request (struct GNUNET_ARM_Handle *h, int ignore_currently_down);


/**
 * Task scheduled to try to re-connect to arm.
 *
 * @param cls the 'struct GNUNET_ARM_Handle'
 */
static void
reconnect_arm_task (void *cls)
{
  struct GNUNET_ARM_Handle *h = cls;

  h->reconnect_task = NULL;
  LOG (GNUNET_ERROR_TYPE_DEBUG, "Connecting to ARM service after delay\n");
  reconnect_arm (h);
}


/**
 * Close down any existing connection to the ARM service and
 * try re-establishing it later.
 *
 * @param h our handle
 */
static void
reconnect_arm_later (struct GNUNET_ARM_Handle *h)
{
  if (GNUNET_NO != h->currently_down)
    return;
  if (NULL != h->cth)
  {
    GNUNET_CLIENT_notify_transmit_ready_cancel (h->cth);
    h->cth = NULL;
  }
  if (NULL != h->client)
  {
    GNUNET_CLIENT_disconnect (h->client);
    h->client = NULL;
  }
  h->currently_down = GNUNET_YES;
  GNUNET_assert (NULL == h->reconnect_task);
  h->reconnect_task =
      GNUNET_SCHEDULER_add_delayed (h->retry_backoff,
				    &reconnect_arm_task,
				    h);
  /* Don't clear pending messages on disconnection, deliver them later
  clear_pending_messages (h, GNUNET_ARM_REQUEST_DISCONNECTED);
  GNUNET_assert (NULL == h->control_pending_head);
  */
  h->retry_backoff = GNUNET_TIME_STD_BACKOFF (h->retry_backoff);
  if (NULL != h->conn_status)
    h->conn_status (h->conn_status_cls, GNUNET_NO);
}


/**
 * Find a control message by its unique ID.
 *
 * @param h ARM handle
 * @param id unique message ID to use for the lookup
 * @return NULL if not found
 */
static struct ARMControlMessage *
find_cm_by_id (struct GNUNET_ARM_Handle *h, uint64_t id)
{
  struct ARMControlMessage *result;
  for (result = h->control_sent_head; result; result = result->next)
    if (id == result->msg->request_id)
      return result;
  return NULL;
}


/**
 * Handler for ARM 'termination' reply (failure to receive).
 *
 * @param cls our "struct GNUNET_ARM_Handle"
 * @param msg expected to be NULL
 */
static void
arm_termination_handler (void *cls, const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_ARM_Handle *h = cls;
  struct ARMControlMessage *cm;

  if (NULL != msg)
  {
    GNUNET_break (0);
    GNUNET_CLIENT_receive (h->client, &arm_termination_handler, h,
			   GNUNET_TIME_UNIT_FOREVER_REL);
    return;
  }
  cm = h->thm;
  h->thm = NULL;
  h->currently_down = GNUNET_YES;
  GNUNET_CLIENT_disconnect (h->client);
  h->client = NULL;
  if (NULL != cm->result_cont)
    cm->result_cont (cm->cont_cls,
		     GNUNET_ARM_REQUEST_SENT_OK,
		     (const char *) &cm->msg[1],
		     GNUNET_ARM_RESULT_STOPPED);
  GNUNET_free (cm->msg);
  GNUNET_free (cm);
}


/**
 * Handler for ARM replies.
 *
 * @param cls our `struct GNUNET_ARM_Handle`
 * @param msg the message received from the arm service
 */
static void
client_notify_handler (void *cls,
                       const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_ARM_Handle *h = cls;
  const struct GNUNET_ARM_Message *arm_msg;
  const struct GNUNET_ARM_ResultMessage *res;
  const struct GNUNET_ARM_ListResultMessage *lres;
  struct ARMControlMessage *cm;
  const char **list;
  const char *pos;
  uint64_t id;
  enum GNUNET_ARM_Result result;
  uint16_t size_check;
  uint16_t rcount;
  uint16_t msize;
  unsigned char fail;

  list = NULL;
  rcount = 0;
  if (NULL == msg)
  {
    LOG (GNUNET_ERROR_TYPE_INFO,
         _("Client was disconnected from arm service, trying to reconnect.\n"));
    reconnect_arm_later (h);
    return;
  }
  msize = ntohs (msg->size);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Processing message of type %u and size %u from arm service\n",
       ntohs (msg->type), msize);
  if (msize < sizeof (struct GNUNET_ARM_Message))
  {
    GNUNET_break (0);
    reconnect_arm_later (h);
    return;
  }
  arm_msg = (const struct GNUNET_ARM_Message *) msg;
  GNUNET_break (0 == ntohl (arm_msg->reserved));
  id = GNUNET_ntohll (arm_msg->request_id);
  cm = find_cm_by_id (h, id);
  if (NULL == cm)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Message with unknown id %llu\n",
         id);
    return;
  }
  fail = GNUNET_NO;
  switch (ntohs (msg->type))
  {
  case GNUNET_MESSAGE_TYPE_ARM_RESULT:
    if (msize < sizeof (struct GNUNET_ARM_ResultMessage))
    {
      GNUNET_assert (0);
      fail = GNUNET_YES;
    }
    break;
  case GNUNET_MESSAGE_TYPE_ARM_LIST_RESULT:
    if (msize < sizeof (struct GNUNET_ARM_ListResultMessage))
    {
      GNUNET_break (0);
      fail = GNUNET_YES;
      break;
    }
    size_check = 0;
    lres = (const struct GNUNET_ARM_ListResultMessage *) msg;
    rcount = ntohs (lres->count);
    {
      unsigned int i;

      list = GNUNET_malloc (sizeof (const char *) * rcount);
      pos = (const char *)&lres[1];
      for (i = 0; i < rcount; i++)
      {
        const char *end = memchr (pos, 0, msize - size_check);
        if (NULL == end)
        {
          GNUNET_break (0);
          fail = GNUNET_YES;
          break;
        }
        list[i] = pos;
        size_check += (end - pos) + 1;
        pos = end + 1;
      }
      if (GNUNET_YES == fail)
      {
        GNUNET_free (list);
        list = NULL;
      }
    }
    break;
  default:
    fail = GNUNET_YES;
    break;
  }
  GNUNET_assert (NULL != cm->timeout_task_id);
  GNUNET_SCHEDULER_cancel (cm->timeout_task_id);
  GNUNET_CONTAINER_DLL_remove (h->control_sent_head,
                               h->control_sent_tail, cm);
  if (GNUNET_YES == fail)
  {
    reconnect_arm_later (h);
    GNUNET_free (cm->msg);
    GNUNET_free (cm);
    return;
  }
  if ( (GNUNET_MESSAGE_TYPE_ARM_RESULT == ntohs (msg->type)) &&
       (0 == strcasecmp ((const char *) &cm->msg[1],
			 "arm")) &&
       (NULL != (res = (const struct GNUNET_ARM_ResultMessage *) msg)) &&
       (GNUNET_ARM_RESULT_STOPPING == ntohl (res->result)) )
  {
    /* special case: if we are stopping 'gnunet-service-arm', we do not just
       wait for the result message, but also wait for the service to close
       the connection (and then we have to close our client handle as well);
       this is done by installing a different receive handler, waiting for
       the connection to go down */
    if (NULL != h->thm)
    {
      GNUNET_break (0);
      cm->result_cont (h->thm->cont_cls,
		       GNUNET_ARM_REQUEST_SENT_OK,
                       (const char *) &h->thm->msg[1],
		       GNUNET_ARM_RESULT_IS_NOT_KNOWN);
      GNUNET_free (h->thm->msg);
      GNUNET_free (h->thm);
    }
    h->thm = cm;
    GNUNET_CLIENT_receive (h->client, &arm_termination_handler, h,
			   GNUNET_TIME_UNIT_FOREVER_REL);
    return;
  }
  GNUNET_CLIENT_receive (h->client, &client_notify_handler, h,
                         GNUNET_TIME_UNIT_FOREVER_REL);
  switch (ntohs (msg->type))
  {
  case GNUNET_MESSAGE_TYPE_ARM_RESULT:
    res = (const struct GNUNET_ARM_ResultMessage *) msg;
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Received response from ARM for service `%s': %u\n",
         (const char *) &cm->msg[1], ntohs (msg->type));
    result = (enum GNUNET_ARM_Result) ntohl (res->result);
    if (NULL != cm->result_cont)
      cm->result_cont (cm->cont_cls, GNUNET_ARM_REQUEST_SENT_OK,
                       (const char *) &cm->msg[1], result);
    break;
  case GNUNET_MESSAGE_TYPE_ARM_LIST_RESULT:
    if (NULL != cm->list_cont)
        cm->list_cont (cm->cont_cls, GNUNET_ARM_REQUEST_SENT_OK, rcount,
                       list);
    GNUNET_free_non_null (list);
    break;
  }
  GNUNET_free (cm->msg);
  GNUNET_free (cm);
}


/**
 * Transmit the next message to the arm service.
 *
 * @param cls closure with the `struct GNUNET_ARM_Handle`
 * @param size number of bytes available in @a buf
 * @param buf where the callee should write the message
 * @return number of bytes written to @a buf
 */
static size_t
transmit_arm_message (void *cls, size_t size, void *buf)
{
  struct GNUNET_ARM_Handle *h = cls;
  struct ARMControlMessage *cm;
  struct GNUNET_ARM_Message *arm_msg;
  uint64_t request_id;
  int notify_connection;
  uint16_t msize;

  notify_connection = GNUNET_NO;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "transmit_arm_message is running with %p buffer of size %lu. ARM is known to be %s\n",
       buf, size, h->currently_down ? "unconnected" : "connected");
  GNUNET_assert (NULL == h->reconnect_task);
  h->cth = NULL;
  if ((GNUNET_YES == h->currently_down) && (NULL != buf))
  {
    h->currently_down = GNUNET_NO;
    notify_connection = GNUNET_YES;
    h->retry_backoff = GNUNET_TIME_UNIT_MILLISECONDS;
    GNUNET_CLIENT_receive (h->client, &client_notify_handler, h,
                           GNUNET_TIME_UNIT_FOREVER_REL);
  }
  if (NULL == buf)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Transmission failed, initiating reconnect\n");
    reconnect_arm_later (h);
    return 0;
  }
  if (NULL == (cm = h->control_pending_head))
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Queue is empty, not sending anything\n");
    msize = 0;
    goto end;
  }
  GNUNET_assert (NULL != cm->msg);
  msize = ntohs (cm->msg->header.size);
  if (size < msize)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Request is too big (%u < %u), not sending it\n", size, msize);
    trigger_next_request (h, GNUNET_NO);
    msize = 0;
    goto end;
  }
  arm_msg = cm->msg;
  if (0 == h->request_id_counter)
    h->request_id_counter++;
  request_id = h->request_id_counter++;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Transmitting control message with %u bytes of type %u to arm with id %llu\n",
       (unsigned int) msize, (unsigned int) ntohs (cm->msg->header.type), request_id);
  arm_msg->reserved = htonl (0);
  arm_msg->request_id = GNUNET_htonll (request_id);
  memcpy (buf, cm->msg, msize);
  /* Otherwise we won't be able to find it later! */
  arm_msg->request_id = request_id;
  GNUNET_CONTAINER_DLL_remove (h->control_pending_head,
                               h->control_pending_tail, cm);
  GNUNET_CONTAINER_DLL_insert_tail (h->control_sent_head,
                                    h->control_sent_tail, cm);
  /* Don't free msg, keep it around (kind of wasteful, but then we don't
   * really have many messages to handle, and it'll be freed when it times
   * out anyway.
   */
  trigger_next_request (h, GNUNET_NO);

 end:
  if ((GNUNET_YES == notify_connection) && (NULL != h->conn_status))
    h->conn_status (h->conn_status_cls, GNUNET_YES);
  return msize;
}


/**
 * Check the list of pending requests, send the next
 * one to the arm.
 *
 * @param h arm handle
 * @param ignore_currently_down transmit message even if not initialized?
 */
static void
trigger_next_request (struct GNUNET_ARM_Handle *h, int ignore_currently_down)
{
  uint16_t msize;

  msize = sizeof (struct GNUNET_MessageHeader);
  if ((GNUNET_YES == h->currently_down) && (ignore_currently_down == GNUNET_NO))
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "ARM connection down, not processing queue\n");
    return;
  }
  if (NULL != h->cth)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG, "Request pending, not processing queue\n");
    return;
  }
  if (NULL != h->control_pending_head)
    msize =
        ntohs (h->control_pending_head->msg->header.size);
  else if (GNUNET_NO == ignore_currently_down)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Request queue empty, not processing queue\n");
    return;                     /* no pending message */
  }
  h->cth =
      GNUNET_CLIENT_notify_transmit_ready (h->client, msize,
                                           GNUNET_TIME_UNIT_FOREVER_REL,
                                           GNUNET_NO, &transmit_arm_message, h);
}


/**
 * Connect to arm.
 *
 * @param h arm handle
 * @return GNUNET_OK on success, GNUNET_SYSERR on failure
 */
static int
reconnect_arm (struct GNUNET_ARM_Handle *h)
{
  GNUNET_assert (NULL == h->client);
  GNUNET_assert (GNUNET_YES == h->currently_down);
  h->client = GNUNET_CLIENT_connect ("arm", h->cfg);
  if (NULL == h->client)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
	   "arm_api, GNUNET_CLIENT_connect returned NULL\n");
    if (NULL != h->conn_status)
      h->conn_status (h->conn_status_cls, GNUNET_SYSERR);
    return GNUNET_SYSERR;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
	 "arm_api, GNUNET_CLIENT_connect returned non-NULL\n");
  trigger_next_request (h, GNUNET_YES);
  return GNUNET_OK;
}


/**
 * Set up a context for communicating with ARM, then
 * start connecting to the ARM service using that context.
 *
 * @param cfg configuration to use (needed to contact ARM;
 *        the ARM service may internally use a different
 *        configuration to determine how to start the service).
 * @param conn_status will be called when connecting/disconnecting
 * @param cls closure for conn_status
 * @return context to use for further ARM operations, NULL on error.
 */
struct GNUNET_ARM_Handle *
GNUNET_ARM_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
                    GNUNET_ARM_ConnectionStatusCallback conn_status,
		    void *cls)
{
  struct GNUNET_ARM_Handle *h;

  h = GNUNET_new (struct GNUNET_ARM_Handle);
  h->cfg = GNUNET_CONFIGURATION_dup (cfg);
  h->currently_down = GNUNET_YES;
  h->reconnect_task = NULL;
  h->conn_status = conn_status;
  h->conn_status_cls = cls;
  if (GNUNET_OK != reconnect_arm (h))
  {
    GNUNET_free (h);
    return NULL;
  }
  return h;
}


/**
 * Disconnect from the ARM service (if connected) and destroy the context.
 *
 * @param h the handle that was being used
 */
void
GNUNET_ARM_disconnect_and_free (struct GNUNET_ARM_Handle *h)
{
  struct ARMControlMessage *cm;

  LOG (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting from ARM service\n");
  if (NULL != h->cth)
  {
    GNUNET_CLIENT_notify_transmit_ready_cancel (h->cth);
    h->cth = NULL;
  }
  while ((NULL != (cm = h->control_pending_head))
         || (NULL != (cm = h->control_sent_head)) )
  {
    if (NULL != h->control_pending_head)
      GNUNET_CONTAINER_DLL_remove (h->control_pending_head,
                                   h->control_pending_tail, cm);
    else
      GNUNET_CONTAINER_DLL_remove (h->control_sent_head,
                                   h->control_sent_tail, cm);
    GNUNET_assert (NULL != cm->timeout_task_id);
    GNUNET_SCHEDULER_cancel (cm->timeout_task_id);
    if (NULL != cm->result_cont)
      cm->result_cont (cm->cont_cls, GNUNET_ARM_REQUEST_DISCONNECTED,
                       NULL, 0);
    /* FIXME: What about list callback? */
    GNUNET_free_non_null (cm->msg);
    GNUNET_free (cm);
  }
  if (NULL != h->client)
  {
    GNUNET_CLIENT_disconnect (h->client);
    h->client = NULL;
  }
  if (NULL != h->reconnect_task)
  {
    GNUNET_SCHEDULER_cancel (h->reconnect_task);
    h->reconnect_task = NULL;
  }
  if (GNUNET_NO == h->service_test_is_active)
  {
    GNUNET_CONFIGURATION_destroy (h->cfg);
    GNUNET_free (h);
  }
}


/**
 * Message timed out. Remove it from the queue.
 *
 * @param cls the message (struct ARMControlMessage *)
 */
static void
control_message_timeout (void *cls)
{
  struct ARMControlMessage *cm = cls;
  struct GNUNET_ARM_Message *arm_msg;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Control message timed out\n");
  arm_msg = cm->msg;
  if ((NULL == arm_msg) || (0 == arm_msg->request_id))
  {
    GNUNET_CONTAINER_DLL_remove (cm->h->control_pending_head,
                                 cm->h->control_pending_tail, cm);
  }
  else
  {
    GNUNET_CONTAINER_DLL_remove (cm->h->control_sent_head,
                                 cm->h->control_sent_tail, cm);
  }
  if (NULL != cm->result_cont)
    cm->result_cont (cm->cont_cls, GNUNET_ARM_REQUEST_TIMEOUT, NULL, 0);
  else if (NULL != cm->list_cont)
    cm->list_cont (cm->cont_cls, GNUNET_ARM_REQUEST_TIMEOUT, 0, NULL);
  GNUNET_free_non_null (cm->msg);
  GNUNET_free (cm);
}


/**
 * A client specifically requested starting of ARM itself.
 * This function is called with information about whether
 * or not ARM is running; if it is, report success.  If
 * it is not, start the ARM process.
 *
 * @param cls the context for the request that we will report on (struct ARMControlMessage *)
 * @param result #GNUNET_YES if ARM is running
 */
static void
arm_service_report (void *cls,
		    int result)
{
  struct ARMControlMessage *cm = cls;
  struct GNUNET_ARM_Handle *h;
  struct GNUNET_OS_Process *proc;
  unsigned char test_is_active;
  char *cbinary;
  char *binary;
  char *quotedbinary;
  char *config;
  char *loprefix;
  char *lopostfix;

  test_is_active = cm->h->service_test_is_active;
  if ((GNUNET_YES == test_is_active) &&
      (GNUNET_YES == result))
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
	 "Looks like `%s' is already running.\n",
	 "gnunet-service-arm");
    /* arm is running! */
    if (cm->result_cont)
      cm->result_cont (cm->cont_cls,
		       GNUNET_ARM_REQUEST_SENT_OK, "arm",
		       GNUNET_ARM_RESULT_IS_STARTED_ALREADY);
  }
  if (GNUNET_NO == test_is_active)
  {
    /* User disconnected & destroyed ARM handle in the middle of
     * the service test, so we kept the handle around until now.
     */
    GNUNET_CONFIGURATION_destroy (cm->h->cfg);
    GNUNET_free (cm->h);
  }
  if ((GNUNET_YES == result) ||
      (GNUNET_NO == test_is_active))
  {
    GNUNET_free (cm);
    return;
  }
  cm->h->service_test_is_active = GNUNET_NO;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Looks like `%s' is not running, will start it.\n",
       "gnunet-service-arm");
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (
      cm->h->cfg, "arm", "PREFIX", &loprefix))
    loprefix = GNUNET_strdup ("");
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (
      cm->h->cfg, "arm", "OPTIONS", &lopostfix))
    lopostfix = GNUNET_strdup ("");
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (cm->h->cfg,
                                             "arm",
                                             "BINARY",
                                             &cbinary))
  {
    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_WARNING,
                               "arm",
                               "BINARY");
    if (cm->result_cont)
      cm->result_cont (cm->cont_cls,
		       GNUNET_ARM_REQUEST_SENT_OK, "arm",
		       GNUNET_ARM_RESULT_IS_NOT_KNOWN);
    GNUNET_free (cm);
    GNUNET_free (loprefix);
    GNUNET_free (lopostfix);
    return;
  }
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (cm->h->cfg,
                                               "arm", "CONFIG",
                                               &config))
    config = NULL;
  binary = GNUNET_OS_get_libexec_binary_path (cbinary);
  GNUNET_asprintf (&quotedbinary,
		   "\"%s\"",
		   binary);
  GNUNET_free (cbinary);
  if ( (GNUNET_YES ==
        GNUNET_CONFIGURATION_have_value (cm->h->cfg,
                                         "TESTING",
                                         "WEAKRANDOM")) &&
       (GNUNET_YES ==
        GNUNET_CONFIGURATION_get_value_yesno (cm->h->cfg,
                                              "TESTING",
                                              "WEAKRANDOM")) &&
       (GNUNET_NO ==
        GNUNET_CONFIGURATION_have_value (cm->h->cfg,
                                         "TESTING",
                                         "HOSTFILE")))
  {
    /* Means we are ONLY running locally */
    /* we're clearly running a test, don't daemonize */
    if (NULL == config)
      proc = GNUNET_OS_start_process_s (GNUNET_NO, cm->std_inheritance,
                                        NULL, loprefix, quotedbinary,
                                        /* no daemonization! */
                                        lopostfix, NULL);
    else
      proc = GNUNET_OS_start_process_s (GNUNET_NO, cm->std_inheritance,
                                        NULL, loprefix, quotedbinary, "-c", config,
                                        /* no daemonization! */
                                        lopostfix, NULL);
  }
  else
  {
    if (NULL == config)
      proc = GNUNET_OS_start_process_s (GNUNET_NO, cm->std_inheritance,
                                        NULL, loprefix, quotedbinary,
                                        "-d", lopostfix, NULL);
    else
      proc = GNUNET_OS_start_process_s (GNUNET_NO, cm->std_inheritance,
                                        NULL, loprefix, quotedbinary, "-c",
                                        config,
                                        "-d", lopostfix, NULL);
  }
  GNUNET_free (binary);
  GNUNET_free (quotedbinary);
  GNUNET_free_non_null (config);
  GNUNET_free (loprefix);
  GNUNET_free (lopostfix);
  if (NULL == proc)
  {
    if (cm->result_cont)
      cm->result_cont (cm->cont_cls,
                       GNUNET_ARM_REQUEST_SENT_OK, "arm",
                       GNUNET_ARM_RESULT_START_FAILED);
    GNUNET_free (cm);
    return;
  }
  if (cm->result_cont)
    cm->result_cont (cm->cont_cls,
                     GNUNET_ARM_REQUEST_SENT_OK, "arm",
                     GNUNET_ARM_RESULT_STARTING);
  GNUNET_OS_process_destroy (proc);
  h = cm->h;
  GNUNET_free (cm);
  reconnect_arm (h);
}


/**
 * Start or stop a service.
 *
 * @param h handle to ARM
 * @param service_name name of the service
 * @param timeout how long to wait before failing for good
 * @param cb callback to invoke when service is ready
 * @param cb_cls closure for callback
 * @param type type of the request
 */
static void
change_service (struct GNUNET_ARM_Handle *h, const char *service_name,
		struct GNUNET_TIME_Relative timeout, GNUNET_ARM_ResultCallback cb,
		void *cb_cls, uint16_t type)
{
  struct ARMControlMessage *cm;
  size_t slen;
  struct GNUNET_ARM_Message *msg;

  slen = strlen (service_name) + 1;
  if (slen + sizeof (struct GNUNET_ARM_Message) >=
      GNUNET_SERVER_MAX_MESSAGE_SIZE)
  {
    GNUNET_break (0);
    if (cb != NULL)
      cb (cb_cls, GNUNET_ARM_REQUEST_TOO_LONG, NULL, 0);
    return;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG, "Requesting %s of service `%s'.\n",
       (GNUNET_MESSAGE_TYPE_ARM_START == type) ? "start" : "termination",
       service_name);
  cm = GNUNET_malloc (sizeof (struct ARMControlMessage) + slen);
  cm->h = h;
  cm->result_cont = cb;
  cm->cont_cls = cb_cls;
  cm->timeout = GNUNET_TIME_relative_to_absolute (timeout);
  memcpy (&cm[1], service_name, slen);
  msg = GNUNET_malloc (sizeof (struct GNUNET_ARM_Message) + slen);
  msg->header.size = htons (sizeof (struct GNUNET_ARM_Message) + slen);
  msg->header.type = htons (type);
  msg->reserved = htonl (0);
  memcpy (&msg[1], service_name, slen);
  cm->msg = msg;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
      "Inserting a control message into the queue. Timeout is %s\n",
       GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_remaining (cm->timeout),
					       GNUNET_NO));
  GNUNET_CONTAINER_DLL_insert_tail (h->control_pending_head,
                                    h->control_pending_tail, cm);
  cm->timeout_task_id =
      GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
                                    (cm->timeout),
				    &control_message_timeout, cm);
  trigger_next_request (h, GNUNET_NO);
}


/**
 * Request for a service to be started.
 *
 * @param h handle to ARM
 * @param service_name name of the service
 * @param std_inheritance inheritance of std streams
 * @param timeout how long to wait before failing for good
 * @param cont callback to invoke after request is sent or not sent
 * @param cont_cls closure for callback
 */
void
GNUNET_ARM_request_service_start (struct GNUNET_ARM_Handle *h,
				  const char *service_name,
				  enum GNUNET_OS_InheritStdioFlags std_inheritance,
				  struct GNUNET_TIME_Relative timeout,
				  GNUNET_ARM_ResultCallback cont,
				  void *cont_cls)
{
  struct ARMControlMessage *cm;
  size_t slen;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Asked to start service `%s' within %s\n", service_name,
       GNUNET_STRINGS_relative_time_to_string (timeout, GNUNET_NO));
  if (0 == strcasecmp ("arm", service_name))
  {
    /* Possible cases:
     * 1) We're connected to ARM already. Invoke the callback immediately.
     * 2) We're not connected to ARM.
     *    Cancel any reconnection attempts temporarily, then perform
     *    a service test.
     */
    if (GNUNET_NO == h->currently_down)
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "ARM is already running\n");
      if (NULL != cont)
        cont (cont_cls,
              GNUNET_ARM_REQUEST_SENT_OK,
              "arm",
              GNUNET_ARM_RESULT_IS_STARTED_ALREADY);
    }
    else if (GNUNET_NO == h->service_test_is_active)
    {
      if (NULL != h->cth)
      {
        GNUNET_CLIENT_notify_transmit_ready_cancel (h->cth);
        h->cth = NULL;
      }
      if (NULL != h->client)
      {
        GNUNET_CLIENT_disconnect (h->client);
        h->client = NULL;
      }
      if (NULL != h->reconnect_task)
      {
        GNUNET_SCHEDULER_cancel (h->reconnect_task);
        h->reconnect_task = NULL;
      }

      LOG (GNUNET_ERROR_TYPE_DEBUG,
          "Not connected to ARM, will do a service test\n");

      slen = strlen ("arm") + 1;
      cm = GNUNET_malloc (sizeof (struct ARMControlMessage) + slen);
      cm->h = h;
      cm->result_cont = cont;
      cm->cont_cls = cont_cls;
      cm->timeout = GNUNET_TIME_relative_to_absolute (timeout);
      cm->std_inheritance = std_inheritance;
      memcpy (&cm[1], service_name, slen);
      h->service_test_is_active = GNUNET_YES;
      GNUNET_CLIENT_service_test ("arm",
                                  h->cfg,
                                  timeout,
                                  &arm_service_report,
				  cm);
    }
    else
    {
      /* Service test is already running - tell user to chill out and try
       * again later.
       */
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "Service test is already in progress, we're busy\n");
      if (NULL != cont)
        cont (cont_cls, GNUNET_ARM_REQUEST_BUSY, NULL, 0);
    }
    return;
  }
  change_service (h, service_name, timeout, cont, cont_cls,
		  GNUNET_MESSAGE_TYPE_ARM_START);
}


/**
 * Request a service to be stopped.
 * Stopping arm itself will not invalidate its handle, and
 * ARM API will try to restore connection to the ARM service,
 * even if ARM connection was lost because you asked for ARM to be stopped.
 * Call #GNUNET_ARM_disconnect_and_free() to free the handle and prevent
 * further connection attempts.
 *
 * @param h handle to ARM
 * @param service_name name of the service
 * @param timeout how long to wait before failing for good
 * @param cont callback to invoke after request is sent or is not sent
 * @param cont_cls closure for callback
 */
void
GNUNET_ARM_request_service_stop (struct GNUNET_ARM_Handle *h,
				 const char *service_name,
				 struct GNUNET_TIME_Relative timeout,
				 GNUNET_ARM_ResultCallback cont,
				 void *cont_cls)
{
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Stopping service `%s' within %s\n",
       service_name,
       GNUNET_STRINGS_relative_time_to_string (timeout, GNUNET_NO));
  change_service (h, service_name, timeout, cont, cont_cls,
		  GNUNET_MESSAGE_TYPE_ARM_STOP);
}


/**
 * Request a list of running services.
 *
 * @param h handle to ARM
 * @param timeout how long to wait before failing for good
 * @param cont callback to invoke after request is sent or is not sent
 * @param cont_cls closure for callback
 */
void
GNUNET_ARM_request_service_list (struct GNUNET_ARM_Handle *h,
                                 struct GNUNET_TIME_Relative timeout,
                                 GNUNET_ARM_ServiceListCallback cont,
                                 void *cont_cls)
{
  struct ARMControlMessage *cm;
  struct GNUNET_ARM_Message *msg;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Requesting LIST from ARM service with timeout: %s\n",
       GNUNET_STRINGS_relative_time_to_string (timeout, GNUNET_YES));
  cm = GNUNET_new (struct ARMControlMessage);
  cm->h = h;
  cm->list_cont = cont;
  cm->cont_cls = cont_cls;
  cm->timeout = GNUNET_TIME_relative_to_absolute (timeout);
  msg = GNUNET_malloc (sizeof (struct GNUNET_ARM_Message));
  msg->header.size = htons (sizeof (struct GNUNET_ARM_Message));
  msg->header.type = htons (GNUNET_MESSAGE_TYPE_ARM_LIST);
  msg->reserved = htonl (0);
  cm->msg = msg;
  GNUNET_CONTAINER_DLL_insert_tail (h->control_pending_head,
                                    h->control_pending_tail, cm);
  cm->timeout_task_id =
      GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
                                    (cm->timeout),
				    &control_message_timeout, cm);
  trigger_next_request (h, GNUNET_NO);
}


/* end of arm_api.c */