summaryrefslogtreecommitdiff
path: root/src/mint/taler-mint-httpd_parsing.c
blob: a1c189176049b7d632290c9d66d53faaec89a296 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
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
/*
  This file is part of TALER
  Copyright (C) 2014, 2015 GNUnet e.V.

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

  TALER 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License along with
  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
*/

/**
 * @file taler-mint-httpd_parsing.c
 * @brief functions to parse incoming requests (MHD arguments and JSON snippets)
 * @author Florian Dold
 * @author Benedikt Mueller
 * @author Christian Grothoff
 */

#include "platform.h"
#include <gnunet/gnunet_util_lib.h>
#include "taler-mint-httpd_parsing.h"
#include "taler-mint-httpd_responses.h"


/**
 * Initial size for POST
 * request buffer.
 */
#define REQUEST_BUFFER_INITIAL 1024

/**
 * Maximum POST request size
 */
#define REQUEST_BUFFER_MAX (1024*1024)


/**
 * Buffer for POST requests.
 */
struct Buffer
{
  /**
   * Allocated memory
   */
  char *data;

  /**
   * Number of valid bytes in buffer.
   */
  size_t fill;

  /**
   * Number of allocated bytes in buffer.
   */
  size_t alloc;
};


/**
 * Initialize a buffer.
 *
 * @param buf the buffer to initialize
 * @param data the initial data
 * @param data_size size of the initial data
 * @param alloc_size size of the buffer
 * @param max_size maximum size that the buffer can grow to
 * @return a GNUnet result code
 */
static int
buffer_init (struct Buffer *buf,
             const void *data,
             size_t data_size,
             size_t alloc_size,
             size_t max_size)
{
  if (data_size > max_size || alloc_size > max_size)
    return GNUNET_SYSERR;
  if (data_size > alloc_size)
    alloc_size = data_size;
  buf->data = GNUNET_malloc (alloc_size);
  memcpy (buf->data, data, data_size);
  return GNUNET_OK;
}


/**
 * Free the data in a buffer.  Does *not* free
 * the buffer object itself.
 *
 * @param buf buffer to de-initialize
 */
static void
buffer_deinit (struct Buffer *buf)
{
  GNUNET_free (buf->data);
  buf->data = NULL;
}


/**
 * Append data to a buffer, growing the buffer if necessary.
 *
 * @param buf the buffer to append to
 * @param data the data to append
 * @param data_size the size of @a data
 * @param max_size maximum size that the buffer can grow to
 * @return #GNUNET_OK on success,
 *         #GNUNET_NO if the buffer can't accomodate for the new data
 */
static int
buffer_append (struct Buffer *buf,
               const void *data,
               size_t data_size,
               size_t max_size)
{
  if (buf->fill + data_size > max_size)
    return GNUNET_NO;
  if (data_size + buf->fill > buf->alloc)
  {
    char *new_buf;
    size_t new_size = buf->alloc;
    while (new_size < buf->fill + data_size)
      new_size += 2;
    if (new_size > max_size)
      return GNUNET_NO;
    new_buf = GNUNET_malloc (new_size);
    memcpy (new_buf, buf->data, buf->fill);
    buf->data = new_buf;
    buf->alloc = new_size;
  }
  memcpy (buf->data + buf->fill, data, data_size);
  buf->fill += data_size;
  return GNUNET_OK;
}


/**
 * Process a POST request containing a JSON object.  This function
 * realizes an MHD POST processor that will (incrementally) process
 * JSON data uploaded to the HTTP server.  It will store the required
 * state in the @a con_cls, which must be cleaned up using
 * #TMH_PARSE_post_cleanup_callback().
 *
 * @param connection the MHD connection
 * @param con_cls the closure (points to a `struct Buffer *`)
 * @param upload_data the POST data
 * @param upload_data_size number of bytes in @a upload_data
 * @param json the JSON object for a completed request
 * @return
 *    #GNUNET_YES if json object was parsed or at least
 *               may be parsed in the future (call again);
 *               `*json` will be NULL if we need to be called again,
 *                and non-NULL if we are done.
 *    #GNUNET_NO is request incomplete or invalid
 *               (error message was generated)
 *    #GNUNET_SYSERR on internal error
 *               (we could not even queue an error message,
 *                close HTTP session with MHD_NO)
 */
int
TMH_PARSE_post_json (struct MHD_Connection *connection,
                     void **con_cls,
                     const char *upload_data,
                     size_t *upload_data_size,
                     json_t **json)
{
  struct Buffer *r = *con_cls;

  *json = NULL;
  if (NULL == *con_cls)
  {
    /* We are seeing a fresh POST request. */
    r = GNUNET_new (struct Buffer);
    if (GNUNET_OK !=
        buffer_init (r,
                     upload_data,
                     *upload_data_size,
                     REQUEST_BUFFER_INITIAL,
                     REQUEST_BUFFER_MAX))
    {
      *con_cls = NULL;
      buffer_deinit (r);
      GNUNET_free (r);
      return (MHD_NO ==
              TMH_RESPONSE_reply_internal_error (connection,
                                                 "out of memory"))
        ? GNUNET_SYSERR : GNUNET_NO;
    }
    /* everything OK, wait for more POST data */
    *upload_data_size = 0;
    *con_cls = r;
    return GNUNET_YES;
  }
  if (0 != *upload_data_size)
  {
    /* We are seeing an old request with more data available. */

    if (GNUNET_OK !=
        buffer_append (r,
                       upload_data,
                       *upload_data_size,
                       REQUEST_BUFFER_MAX))
    {
      /* Request too long */
      *con_cls = NULL;
      buffer_deinit (r);
      GNUNET_free (r);
      return (MHD_NO ==
              TMH_RESPONSE_reply_request_too_large (connection))
        ? GNUNET_SYSERR : GNUNET_NO;
    }
    /* everything OK, wait for more POST data */
    *upload_data_size = 0;
    return GNUNET_YES;
  }

  /* We have seen the whole request. */

  *json = json_loadb (r->data,
                      r->fill,
                      0,
                      NULL);
  buffer_deinit (r);
  GNUNET_free (r);
  if (NULL == *json)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Failed to parse JSON request body\n");
    return (MHD_YES ==
            TMH_RESPONSE_reply_invalid_json (connection))
      ? GNUNET_NO : GNUNET_SYSERR;
  }
  *con_cls = NULL;

  return GNUNET_YES;
}


/**
 * Function called whenever we are done with a request
 * to clean up our state.
 *
 * @param con_cls value as it was left by
 *        #TMH_PARSE_post_json(), to be cleaned up
 */
void
TMH_PARSE_post_cleanup_callback (void *con_cls)
{
  struct Buffer *r = con_cls;

  if (NULL != r)
    buffer_deinit (r);
}


/**
 * Extract base32crockford encoded data from request.
 *
 * Queues an error response to the connection if the parameter is missing or
 * invalid.
 *
 * @param connection the MHD connection
 * @param param_name the name of the parameter with the key
 * @param[out] out_data pointer to store the result
 * @param out_size expected size of data
 * @return
 *   #GNUNET_YES if the the argument is present
 *   #GNUNET_NO if the argument is absent or malformed
 *   #GNUNET_SYSERR on internal error (error response could not be sent)
 */
int
TMH_PARSE_mhd_request_arg_data (struct MHD_Connection *connection,
                                const char *param_name,
                                void *out_data,
                                size_t out_size)
{
  const char *str;

  str = MHD_lookup_connection_value (connection,
                                     MHD_GET_ARGUMENT_KIND,
                                     param_name);
  if (NULL == str)
  {
    return (MHD_NO ==
            TMH_RESPONSE_reply_arg_missing (connection, param_name))
      ? GNUNET_SYSERR : GNUNET_NO;
  }
  if (GNUNET_OK !=
      GNUNET_STRINGS_string_to_data (str,
                                     strlen (str),
                                     out_data,
                                     out_size))
    return (MHD_NO ==
            TMH_RESPONSE_reply_arg_invalid (connection, param_name))
      ? GNUNET_SYSERR : GNUNET_NO;
  return GNUNET_OK;
}


/**
 * Extraxt variable-size base32crockford encoded data from request.
 *
 * Queues an error response to the connection if the parameter is missing
 * or the encoding is invalid.
 *
 * @param connection the MHD connection
 * @param param_name the name of the parameter with the key
 * @param[out] out_data pointer to allocate buffer and store the result
 * @param[out] out_size set to the size of the buffer allocated in @a out_data
 * @return
 *   #GNUNET_YES if the the argument is present
 *   #GNUNET_NO if the argument is absent or malformed
 *   #GNUNET_SYSERR on internal error (error response could not be sent)
 */
int
TMH_PARSE_mhd_request_var_arg_data (struct MHD_Connection *connection,
                                    const char *param_name,
                                    void **out_data,
                                    size_t *out_size)
{
  const char *str;
  size_t slen;
  size_t olen;
  void *out;

  str = MHD_lookup_connection_value (connection,
                                     MHD_GET_ARGUMENT_KIND,
                                     param_name);
  if (NULL == str)
  {
    return (MHD_NO ==
            TMH_RESPONSE_reply_arg_missing (connection, param_name))
      ? GNUNET_SYSERR : GNUNET_NO;
  }
  slen = strlen (str);
  olen = (slen * 5) / 8;
  out = GNUNET_malloc (olen);
  if (GNUNET_OK !=
      GNUNET_STRINGS_string_to_data (str,
                                     strlen (str),
                                     out,
                                     olen))
  {
    GNUNET_free (out);
    *out_size = 0;
    return (MHD_NO ==
            TMH_RESPONSE_reply_arg_invalid (connection, param_name))
      ? GNUNET_SYSERR : GNUNET_NO;
  }
  *out_data = out;
  *out_size = olen;
  return GNUNET_OK;
}


/**
 * Navigate through a JSON tree.
 *
 * Sends an error response if navigation is impossible (i.e.
 * the JSON object is invalid)
 *
 * @param connection the connection to send an error response to
 * @param root the JSON node to start the navigation at.
 * @param ... navigation specification (see `enum TMH_PARSE_JsonNavigationCommand`)
 * @return
 *    #GNUNET_YES if navigation was successful
 *    #GNUNET_NO if json is malformed, error response was generated
 *    #GNUNET_SYSERR on internal error (no response was generated,
 *                       connection must be closed)
 */
int
TMH_PARSE_navigate_json (struct MHD_Connection *connection,
                         const json_t *root,
                         ...)
{
  va_list argp;
  int ret;
  json_t *path; /* what's our current path from 'root'? */

  path = json_array ();
  va_start (argp, root);
  ret = 2; /* just not any of the valid return values */
  while (2 == ret)
  {
    enum TMH_PARSE_JsonNavigationCommand command
      = va_arg (argp,
                enum TMH_PARSE_JsonNavigationCommand);

    switch (command)
    {
    case TMH_PARSE_JNC_FIELD:
      {
        const char *fname = va_arg(argp, const char *);

        json_array_append_new (path,
                               json_string (fname));
        root = json_object_get (root,
                                fname);
        if (NULL == root)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:s, s:o}",
                                               "error", "missing field in JSON",
                                               "field", fname,
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
      }
      break;

    case TMH_PARSE_JNC_INDEX:
      {
        int fnum = va_arg(argp, int);

        json_array_append_new (path,
                               json_integer (fnum));
        root = json_array_get (root,
                               fnum);
        if (NULL == root)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "missing index in JSON",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
      }
      break;

    case TMH_PARSE_JNC_RET_DATA:
      {
        void *where = va_arg (argp, void *);
        size_t len = va_arg (argp, size_t);
        const char *str;
        int res;

        // FIXME: avoidable code duplication here...
        str = json_string_value (root);
        if (NULL == str)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                             MHD_HTTP_BAD_REQUEST,
                                             "{s:s, s:o}",
                                             "error", "string expected",
                                             "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        res = GNUNET_STRINGS_string_to_data (str, strlen (str),
                                             where, len);
        if (GNUNET_OK != res)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "malformed binary data in JSON",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        ret = GNUNET_OK;
      }
      break;

    case TMH_PARSE_JNC_RET_DATA_VAR:
      {
        void **where = va_arg (argp, void **);
        size_t *len = va_arg (argp, size_t *);
        const char *str;

        // FIXME: avoidable code duplication here...
        str = json_string_value (root);
        if (NULL == str)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_internal_error (connection,
                                                  "json_string_value() failed"))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        *len = (strlen (str) * 5) / 8;
        if (NULL != where)
        {
          int res;

          *where = GNUNET_malloc (*len);
          res = GNUNET_STRINGS_string_to_data (str,
                                               strlen (str),
                                               *where,
                                               *len);
          if (GNUNET_OK != res)
          {
            GNUNET_free (*where);
            *where = NULL;
            *len = 0;
            ret = (MHD_YES ==
                   TMH_RESPONSE_reply_json_pack (connection,
                                                 MHD_HTTP_BAD_REQUEST,
                                                 "{s:s, s:o}",
                                                 "error", "malformed binary data in JSON",
                                                 "path", path))
              ? GNUNET_NO : GNUNET_SYSERR;
            break;
          }
        }
        ret = GNUNET_OK;
      }
      break;

    case TMH_PARSE_JNC_RET_TYPED_JSON:
      {
        int typ = va_arg (argp, int);
        const json_t **r_json = va_arg (argp, const json_t **);

        if ( (-1 != typ) && (json_typeof (root) != typ))
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:i, s:i, s:o}",
                                               "error", "wrong JSON field type",
                                               "type_expected", typ,
                                               "type_actual", json_typeof (root),
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        *r_json = root;
        ret = GNUNET_OK;
      }
      break;

    case TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY:
      {
        struct TALER_DenominationPublicKey *where;
        size_t len;
        const char *str;
        int res;
        void *buf;

        where = va_arg (argp,
                        struct TALER_DenominationPublicKey *);
        str = json_string_value (root);
        if (NULL == str)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "string expected",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        len = (strlen (str) * 5) / 8;
        buf = GNUNET_malloc (len);
        res = GNUNET_STRINGS_string_to_data (str,
                                             strlen (str),
                                             buf,
                                             len);
        if (GNUNET_OK != res)
        {
          GNUNET_free (buf);
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "malformed binary data in JSON",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        where->rsa_public_key = GNUNET_CRYPTO_rsa_public_key_decode (buf,
                                                                     len);
        GNUNET_free (buf);
        if (NULL == where->rsa_public_key)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "malformed RSA public key in JSON",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        ret = GNUNET_OK;
        break;
      }

    case TMH_PARSE_JNC_RET_RSA_SIGNATURE:
      {
        struct TALER_DenominationSignature *where;
        size_t len;
        const char *str;
        int res;
        void *buf;

        where = va_arg (argp,
                        struct TALER_DenominationSignature *);
        str = json_string_value (root);
        if (NULL == str)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "string expected",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        len = (strlen (str) * 5) / 8;
        buf = GNUNET_malloc (len);
        res = GNUNET_STRINGS_string_to_data (str,
                                             strlen (str),
                                             buf,
                                             len);
        if (GNUNET_OK != res)
        {
          GNUNET_free (buf);
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "malformed binary data in JSON",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        where->rsa_signature = GNUNET_CRYPTO_rsa_signature_decode (buf,
                                                                   len);
        GNUNET_free (buf);
        if (NULL == where->rsa_signature)
        {
          ret = (MHD_YES ==
                 TMH_RESPONSE_reply_json_pack (connection,
                                               MHD_HTTP_BAD_REQUEST,
                                               "{s:s, s:o}",
                                               "error", "malformed RSA signature in JSON",
                                               "path", path))
            ? GNUNET_NO : GNUNET_SYSERR;
          break;
        }
        ret = GNUNET_OK;
        break;
      }

    case TMH_PARSE_JNC_RET_AMOUNT:
      {
        struct TALER_Amount *where = va_arg (argp, void *);

        ret = TMH_PARSE_amount_json (connection,
                                     (json_t *) root,
                                     where);
        break;
      }

    case TMH_PARSE_JNC_RET_TIME_ABSOLUTE:
      {
        struct GNUNET_TIME_Absolute *where = va_arg (argp, void *);

        ret = TMH_PARSE_time_abs_json (connection,
                                       (json_t *) root,
                                       where);
        break;
      }

    default:
      GNUNET_break (0);
      ret = (MHD_YES ==
             TMH_RESPONSE_reply_internal_error (connection,
                                                "unhandled value in switch"))
        ? GNUNET_NO : GNUNET_SYSERR;
      break;
    }
  }
  va_end (argp);
  json_decref (path);
  return ret;
}


/**
 * Parse JSON object into components based on the given field
 * specification.
 *
 * @param connection the connection to send an error response to
 * @param root the JSON node to start the navigation at.
 * @param spec field specification for the parser
 * @return
 *    #GNUNET_YES if navigation was successful (caller is responsible
 *                for freeing allocated variable-size data using
 *                #TMH_PARSE_release_data() when done)
 *    #GNUNET_NO if json is malformed, error response was generated
 *    #GNUNET_SYSERR on internal error
 */
int
TMH_PARSE_json_data (struct MHD_Connection *connection,
                            const json_t *root,
                            struct TMH_PARSE_FieldSpecification *spec)
{
  unsigned int i;
  int ret;
  void *ptr;

  ret = GNUNET_YES;
  for (i=0; NULL != spec[i].field_name; i++)
  {
    if (GNUNET_YES != ret)
      break;
    switch (spec[i].command)
    {
    case TMH_PARSE_JNC_FIELD:
      GNUNET_break (0);
      return GNUNET_SYSERR;
    case TMH_PARSE_JNC_INDEX:
      GNUNET_break (0);
      return GNUNET_SYSERR;
    case TMH_PARSE_JNC_RET_DATA:
      ret = TMH_PARSE_navigate_json (connection,
                                     root,
                                     TMH_PARSE_JNC_FIELD,
                                     spec[i].field_name,
                                     TMH_PARSE_JNC_RET_DATA,
                                     spec[i].destination,
                                     spec[i].destination_size_in);
      break;
    case TMH_PARSE_JNC_RET_DATA_VAR:
      ptr = NULL;
      ret = TMH_PARSE_navigate_json (connection,
                                     root,
                                     TMH_PARSE_JNC_FIELD,
                                     spec[i].field_name,
                                     TMH_PARSE_JNC_RET_DATA_VAR,
                                     &ptr,
                                     &spec[i].destination_size_out);
      spec[i].destination = ptr;
      break;
    case TMH_PARSE_JNC_RET_TYPED_JSON:
      ptr = NULL;
      ret = TMH_PARSE_navigate_json (connection,
                                     root,
                                     TMH_PARSE_JNC_FIELD,
                                     spec[i].field_name,
                                     TMH_PARSE_JNC_RET_TYPED_JSON,
                                     spec[i].type,
                                     &ptr);
      *((void**)spec[i].destination) = ptr;
      break;
    case TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY:
      ptr = NULL;
      ret = TMH_PARSE_navigate_json (connection,
                                     root,
                                     TMH_PARSE_JNC_FIELD,
                                     spec[i].field_name,
                                     TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY,
                                     &ptr);
      spec[i].destination = ptr;
      break;
    case TMH_PARSE_JNC_RET_RSA_SIGNATURE:
      ptr = NULL;
      ret = TMH_PARSE_navigate_json (connection,
                                     root,
                                     TMH_PARSE_JNC_FIELD,
                                     spec[i].field_name,
                                     TMH_PARSE_JNC_RET_RSA_SIGNATURE,
                                     &ptr);
      spec[i].destination = ptr;
      break;
    case TMH_PARSE_JNC_RET_AMOUNT:
      GNUNET_assert (sizeof (struct TALER_Amount) ==
                     spec[i].destination_size_in);
      ret = TMH_PARSE_navigate_json (connection,
                                     root,
                                     TMH_PARSE_JNC_FIELD,
                                     spec[i].field_name,
                                     TMH_PARSE_JNC_RET_AMOUNT,
                                     &spec[i].destination);
      break;
    case TMH_PARSE_JNC_RET_TIME_ABSOLUTE:
      GNUNET_assert (sizeof (struct GNUNET_TIME_Absolute) ==
                     spec[i].destination_size_in);
      ret = TMH_PARSE_navigate_json (connection,
                                     root,
                                     TMH_PARSE_JNC_FIELD,
                                     spec[i].field_name,
                                     TMH_PARSE_JNC_RET_TIME_ABSOLUTE,
                                     &spec[i].destination);
      break;
    }
  }
  if (GNUNET_YES != ret)
    TMH_PARSE_release_data (spec);
  return ret;
}


/**
 * Release all memory allocated for the variable-size fields in
 * the parser specification.
 *
 * @param spec specification to free
 */
void
TMH_PARSE_release_data (struct TMH_PARSE_FieldSpecification *spec)
{
  unsigned int i;
  void *ptr;

  for (i=0; NULL != spec[i].field_name; i++)
  {
    switch (spec[i].command)
    {
    case TMH_PARSE_JNC_FIELD:
      GNUNET_break (0);
      return;
    case TMH_PARSE_JNC_INDEX:
      GNUNET_break (0);
      return;
    case TMH_PARSE_JNC_RET_DATA:
      break;
    case TMH_PARSE_JNC_RET_DATA_VAR:
      if (0 != spec[i].destination_size_out)
      {
        GNUNET_free (spec[i].destination);
        spec[i].destination = NULL;
        spec[i].destination_size_out = 0;
      }
      break;
    case TMH_PARSE_JNC_RET_TYPED_JSON:
      ptr = *(void **) spec[i].destination;
      if (NULL != ptr)
      {
        json_decref (ptr);
        *(void**) spec[i].destination = NULL;
      }
      break;
    case TMH_PARSE_JNC_RET_RSA_PUBLIC_KEY:
      {
        struct TALER_DenominationPublicKey pk;

        pk = *(struct TALER_DenominationPublicKey *) spec[i].destination;
        if (NULL != pk.rsa_public_key)
        {
          GNUNET_CRYPTO_rsa_public_key_free (pk.rsa_public_key);
          pk.rsa_public_key = NULL;
        }
      }
      break;
    case TMH_PARSE_JNC_RET_RSA_SIGNATURE:
      {
        struct TALER_DenominationSignature sig;

        sig = *(struct TALER_DenominationSignature *) spec[i].destination;
        if (NULL != sig.rsa_signature)
        {
          GNUNET_CRYPTO_rsa_signature_free (sig.rsa_signature);
          sig.rsa_signature = NULL;
        }
      }
      break;
    case TMH_PARSE_JNC_RET_AMOUNT:
      memset (spec[i].destination,
              0,
              sizeof (struct TALER_Amount));
      break;
    case TMH_PARSE_JNC_RET_TIME_ABSOLUTE:
      break;
    }
  }
}


/**
 * Parse absolute time specified in JSON format.  The JSON format is
 * "/TIMEVAL/" where TIMEVAL is in milliseconds.  Additionally, we
 * support "/forever/" to represent the end of time.
 *
 * @param connection the MHD connection (to report errors)
 * @param f json specification of the amount
 * @param[out] time set to the time specified in @a f
 * @return
 *    #GNUNET_YES if parsing was successful
 *    #GNUNET_NO if json is malformed, error response was generated
 *    #GNUNET_SYSERR on internal error, error response was not generated
 */
int
TMH_PARSE_time_abs_json (struct MHD_Connection *connection,
                         json_t *f,
                         struct GNUNET_TIME_Absolute *time)
{
  const char *val;
  size_t slen;
  unsigned long long int tval;
  char *endp;

  val = json_string_value (f);
  if (NULL == val)
  {
    if (MHD_YES !=
        TMH_RESPONSE_reply_json_pack (connection,
                                      MHD_HTTP_BAD_REQUEST,
                                      "{s:s}",
                                      "error", "string expected"))
      return GNUNET_SYSERR;
    return GNUNET_NO;
  }
  slen = strlen (val);
  if ( (slen <= 2) ||
       ('/' != val[0]) ||
       ('/' != val[slen - 1]) )
  {
    if (MHD_YES !=
        TMH_RESPONSE_reply_json_pack (connection,
                                      MHD_HTTP_BAD_REQUEST,
                                      "{s:s, s:s}",
                                      "error", "timestamp expected",
                                      "value", val))
      return GNUNET_SYSERR;
    return GNUNET_NO;
  }
  if (0 == strcasecmp (val,
                       "/forever/"))
  {
    *time = GNUNET_TIME_UNIT_FOREVER_ABS;
    return GNUNET_OK;
  }
  tval = strtoull (&val[1],
                   &endp,
                   10);
  if (&val[slen - 1] != endp)
  {
    if (MHD_YES !=
        TMH_RESPONSE_reply_json_pack (connection,
                                      MHD_HTTP_BAD_REQUEST,
                                      "{s:s, s:s}",
                                      "error", "timestamp expected",
                                      "value", val))
      return GNUNET_SYSERR;
    return GNUNET_NO;
  }
  /* Time is in 'ms' in JSON, but in microseconds in GNUNET_TIME_Absolute */
  time->abs_value_us = tval * 1000LL;
  if ( (time->abs_value_us) / 1000LL != tval)
  {
    /* Integer overflow */
    if (MHD_YES !=
        TMH_RESPONSE_reply_json_pack (connection,
                                      MHD_HTTP_BAD_REQUEST,
                                      "{s:s, s:s}",
                                      "error", "timestamp outside of legal range",
                                      "value", val))
      return GNUNET_SYSERR;
    return GNUNET_NO;
  }
  return GNUNET_OK;
}


/**
 * Parse amount specified in JSON format.
 *
 * @param connection the MHD connection (to report errors)
 * @param f json specification of the amount
 * @param[out] amount set to the amount specified in @a f
 * @return
 *    #GNUNET_YES if parsing was successful
 *    #GNUNET_NO if json is malformed, error response was generated
 *    #GNUNET_SYSERR on internal error, error response was not generated
 */
int
TMH_PARSE_amount_json (struct MHD_Connection *connection,
                       json_t *f,
                       struct TALER_Amount *amount)
{
  json_int_t value;
  json_int_t fraction;
  const char *currency;

  memset (amount,
          0,
          sizeof (struct TALER_Amount));
  if (-1 == json_unpack (f,
                         "{s:I, s:I, s:s}",
                         "value", &value,
                         "fraction", &fraction,
                         "currency", &currency))
  {
    TALER_LOG_WARNING ("Failed to parse JSON amount specification\n");
    if (MHD_YES !=
        TMH_RESPONSE_reply_json_pack (connection,
                                      MHD_HTTP_BAD_REQUEST,
                                      "{s:s}",
                                      "error", "Bad format"))
      return GNUNET_SYSERR;
    return GNUNET_NO;
  }
  if ( (value < 0) ||
       (fraction < 0) ||
       (value > UINT64_MAX) ||
       (fraction > UINT32_MAX) )
  {
    TALER_LOG_WARNING ("Amount specified not in allowed range\n");
    if (MHD_YES !=
        TMH_RESPONSE_reply_json_pack (connection,
                                      MHD_HTTP_BAD_REQUEST,
                                      "{s:s}",
                                      "error", "Amount outside of allowed range"))
      return GNUNET_SYSERR;
    return GNUNET_NO;
  }
  if (0 != strcmp (currency,
                   TMH_mint_currency_string))
  {
    TALER_LOG_WARNING ("Currency specified not supported by this mint\n");
    if (MHD_YES !=
        TMH_RESPONSE_reply_json_pack (connection,
                                      MHD_HTTP_BAD_REQUEST,
                                      "{s:s, s:s}",
                                      "error", "Currency not supported",
                                      "currency", currency))
      return GNUNET_SYSERR;
    return GNUNET_NO;
  }
  amount->value = (uint64_t) value;
  amount->fraction = (uint32_t) fraction;
  GNUNET_assert (strlen (TMH_mint_currency_string) < TALER_CURRENCY_LEN);
  strcpy (amount->currency, TMH_mint_currency_string);
  (void) TALER_amount_normalize (amount);
  return GNUNET_OK;
}



/* end of taler-mint-httpd_parsing.c */