summaryrefslogtreecommitdiff
path: root/src/exchange/taler-exchange-httpd_wire.c
blob: 876cece1dffad861be830cea4ee171145926f654 (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
/*
  This file is part of TALER
  Copyright (C) 2015-2020 Taler Systems SA

  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, see <http://www.gnu.org/licenses/>
*/
/**
 * @file taler-exchange-httpd_wire.c
 * @brief Handle /wire requests
 * @author Christian Grothoff
 */
#include "platform.h"
#include <gnunet/gnunet_json_lib.h>
#include "taler-exchange-httpd_responses.h"
#include "taler-exchange-httpd_wire.h"
#include "taler_json_lib.h"
#include "taler_mhd_lib.h"
#include <jansson.h>


/**
 * Thread-local.  Contains a pointer to `struct WireStateHandle` or NULL.
 * Stores the per-thread latest generation of our wire response.
 */
static pthread_key_t wire_state;

/**
 * Counter incremented whenever we have a reason to re-build the #wire_state
 * because something external changed (in another thread).  The counter is
 * manipulated using an atomic update, and thus to ensure that threads notice
 * when it changes, the variable MUST be volatile.  See #get_wire_state()
 * and #TEH_wire_update_state() for uses of this variable.
 */
static volatile uint64_t wire_generation;


/**
 * State we keep per thread to cache the /wire response.
 */
struct WireStateHandle
{
  /**
   * Cached JSON for /wire response.
   */
  json_t *wire_reply;

  /**
   * For which (global) wire_generation was this data structure created?
   * Used to check when we are outdated and need to be re-generated.
   */
  uint64_t wire_generation;

};


/**
 * Free memory assciated with @a wsh
 *
 * @param[in] wsh wire state to destroy
 */
static void
destroy_wire_state (struct WireStateHandle *wsh)
{
  json_decref (wsh->wire_reply);
  GNUNET_free (wsh);
}


/**
 * Free memory assciated with wire state. Signature
 * suitable for pthread_key_create().
 *
 * @param[in] cls the `struct WireStateHandle` to destroy
 */static void
destroy_wire_state_cb (void *cls)
{
  struct WireStateHandle *wsh = cls;

  destroy_wire_state (wsh);
}


/**
 * Initialize WIRE submodule.
 *
 * @return #GNUNET_OK on success
 */
int
TEH_WIRE_init ()
{
  if (0 !=
      pthread_key_create (&wire_state,
                          &destroy_wire_state_cb))
    return GNUNET_SYSERR;
  return GNUNET_OK;
}


/**
 * Fully clean up our state.
 */
void
TEH_WIRE_done ()
{
  GNUNET_assert (0 ==
                 pthread_key_delete (wire_state));
}


/**
 * Add information about a wire account to @a cls.
 *
 * @param cls a `json_t *` object to expand with wire account details
 * @param payto_uri the exchange bank account URI to add
 * @param master_sig master key signature affirming that this is a bank
 *                   account of the exchange (of purpose #TALER_SIGNATURE_MASTER_WIRE_DETAILS)
 */
static void
add_wire_account (void *cls,
                  const char *payto_uri,
                  const struct TALER_MasterSignatureP *master_sig)
{
  json_t *a = cls;

  if (0 !=
      json_array_append_new (
        a,
        json_pack ("{s:s, s:o}",
                   "payto_uri",
                   payto_uri,
                   "master_sig",
                   GNUNET_JSON_from_data_auto (master_sig))))
  {
    GNUNET_break (0);   /* out of memory!? */
    return;
  }
}


/**
 * Add information about a wire account to @a cls.
 *
 * @param cls a `json_t *` array to expand with wire account details
 * @param wire_fee the wire fee we charge
 * @param closing_fee the closing fee we charge
 * @param start_date from when are these fees valid (start date)
 * @param end_date until when are these fees valid (end date, exclusive)
 * @param master_sig master key signature affirming that this is the corrrect
 *                   fee (of purpose #TALER_SIGNATURE_MASTER_WIRE_FEES)
 */
static void
add_wire_fee (void *cls,
              const struct TALER_Amount *wire_fee,
              const struct TALER_Amount *closing_fee,
              struct GNUNET_TIME_Absolute start_date,
              struct GNUNET_TIME_Absolute end_date,
              const struct TALER_MasterSignatureP *master_sig)
{
  json_t *a = cls;

  if (0 !=
      json_array_append_new (
        a,
        json_pack ("{s:o, s:o, s:o, s:o, s:o}",
                   "wire_fee",
                   TALER_JSON_from_amount (wire_fee),
                   "closing_fee",
                   TALER_JSON_from_amount (closing_fee),
                   "start_date",
                   GNUNET_JSON_from_time_abs (start_date),
                   "end_date",
                   GNUNET_JSON_from_time_abs (end_date),
                   "sig",
                   GNUNET_JSON_from_data_auto (master_sig))))
  {
    GNUNET_break (0);   /* out of memory!? */
    return;
  }
}


/**
 * Create the /wire response from our database state.
 *
 * @return NULL on error
 */
static struct WireStateHandle *
build_wire_state (void)
{
  json_t *wire_accounts_array;
  json_t *wire_fee_object;
  json_t *wire_reply;
  uint64_t wg = wire_generation; /* must be obtained FIRST */
  enum GNUNET_DB_QueryStatus qs;

  wire_accounts_array = json_array ();
  GNUNET_assert (NULL != wire_accounts_array);
  qs = TEH_plugin->get_wire_accounts (TEH_plugin->cls,
                                      &add_wire_account,
                                      wire_accounts_array);
  if (0 > qs)
  {
    GNUNET_break (0);
    json_decref (wire_accounts_array);
    return NULL;
  }
  if (0 == json_array_size (wire_accounts_array))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "No bank accounts for the exchange configured. Administrator must `enable-account` with taler-exchange-offline!\n");
    json_decref (wire_accounts_array);
    return NULL;
  }
  wire_fee_object = json_object ();
  GNUNET_assert (NULL != wire_fee_object);
  {
    json_t *account;
    size_t index;

    json_array_foreach (wire_accounts_array, index, account) {
      char *wire_method;
      const char *payto_uri = json_string_value (json_object_get (account,
                                                                  "payto_uri"));
      GNUNET_assert (NULL != payto_uri);
      wire_method = TALER_payto_get_method (payto_uri);
      if (NULL == json_object_get (wire_fee_object,
                                   wire_method))
      {
        json_t *a = json_array ();

        GNUNET_assert (NULL != a);
        qs = TEH_plugin->get_wire_fees (TEH_plugin->cls,
                                        wire_method,
                                        &add_wire_fee,
                                        a);
        if (0 > qs)
        {
          GNUNET_break (0);
          json_decref (a);
          json_decref (wire_fee_object);
          json_decref (wire_accounts_array);
          return NULL;
        }
        if (0 == json_array_size (a))
        {
          GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                      "No wire fees for `%s' configured. Administrator must set `wire-fee` with taler-exchange-offline!\n",
                      wire_method);
          json_decref (wire_accounts_array);
          json_decref (wire_fee_object);
          return NULL;
        }
        GNUNET_assert (0 ==
                       json_object_set_new (wire_fee_object,
                                            wire_method,
                                            a));
      }
      GNUNET_free (wire_method);

    }
  }
  wire_reply = json_pack (
    "{s:O, s:O, s:o}",
    "accounts", wire_accounts_array,
    "fees", wire_fee_object,
    "master_public_key",
    GNUNET_JSON_from_data_auto (&TEH_master_public_key));
  GNUNET_assert (NULL != wire_reply);
  {
    struct WireStateHandle *wsh;

    wsh = GNUNET_new (struct WireStateHandle);
    wsh->wire_reply = wire_reply;
    wsh->wire_generation = wg;
    return wsh;
  }
}


void
TEH_wire_update_state (void)
{
  __sync_fetch_and_add (&wire_generation,
                        1);
}


/**
 * Return the current key state for this thread.  Possibly
 * re-builds the key state if we have reason to believe
 * that something changed.
 *
 * @return NULL on error
 */
struct WireStateHandle *
get_wire_state (void)
{
  struct WireStateHandle *old_wsh;
  struct WireStateHandle *wsh;

  old_wsh = pthread_getspecific (wire_state);
  if ( (NULL == old_wsh) ||
       (old_wsh->wire_generation < wire_generation) )
  {
    wsh = build_wire_state ();
    if (NULL == wsh)
      return NULL;
    if (0 != pthread_setspecific (wire_state,
                                  wsh))
    {
      GNUNET_break (0);
      destroy_wire_state (wsh);
      return NULL;
    }
    if (NULL != old_wsh)
      destroy_wire_state (old_wsh);
    return wsh;
  }
  return old_wsh;
}


/**
 * Handle a "/wire" request.
 *
 * @param rh context of the handler
 * @param connection the MHD connection to handle
 * @param args array of additional options (must be empty for this function)
 * @return MHD result code
  */
MHD_RESULT
TEH_handler_wire (const struct TEH_RequestHandler *rh,
                  struct MHD_Connection *connection,
                  const char *const args[])
{
  struct WireStateHandle *wsh;

  (void) rh;
  (void) args;
  wsh = get_wire_state ();
  if (NULL == wsh)
    TALER_MHD_reply_with_error (connection,
                                MHD_HTTP_INTERNAL_SERVER_ERROR,
                                TALER_EC_EXCHANGE_GENERIC_BAD_CONFIGURATION,
                                NULL);
  return TALER_MHD_reply_json (connection,
                               json_incref (wsh->wire_reply),
                               MHD_HTTP_OK);
}


/* end of taler-exchange-httpd_wire.c */