WiP: parsing and replay of auction transcripts

POST handler of auction_brandt extension now parses JSON transcript and
passes JSON via stdin to external program.  Reads result via stdout.

TODOs:
- check signatures in transcript
- parse JSON output of replay progam
- add configuration to to auction_brandt:
	- types of auctions
	- max. concurrent users
	- max. number of prices
	- maximum price
	- fees
- add timeout handler for replay program execution
- (maybe) sign output of exchange by master-key
- (maybe) add GET handler with information re: auction_brandt?

src/extensions/auction_brandt/extension_auction_brandt.c

@@ -27,6 +27,8 @@
 #include <microhttpd.h>
 
 #define AUCTION_BRANDT "auction_brandt"
+#define LOG_PREFIX "[auction_brandt] "
+#define MAX_RESULT_SIZE 10 * 1024
 
 /* Path to the replay program. */
 static char *replay_program;
@@ -77,7 +79,7 @@ json_error (json_t **output,
   GNUNET_assert (*output);
 
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "[auction_brandt] got error: %s\n",
+              LOG_PREFIX "got error: %s\n",
               error);
 
   return GNUNET_SYSERR;
@@ -86,6 +88,7 @@ json_error (json_t **output,
 /**
  * @brief returns an JSON with the result
  */
+#if 0
 static enum GNUNET_GenericReturnValue
 json_result (json_t **output,
              const struct transcript *tr)
@@ -119,6 +122,9 @@ json_result (json_t **output,
 }
 
 
+#endif
+
+
 /*
  * @brief Parses a given json as transcript.
  *
@@ -126,13 +132,16 @@ json_result (json_t **output,
  * @param[out] transcript Parsed transcript data
  * @param[out] jresult JSON output, both, for results or errors
  * @return GNUNET_OK on succes
+ *
+ * TODO:
+ *   - fix leakages
+ *   - parse and verify signatures
  */
 static enum GNUNET_GenericReturnValue
 parse_transcript (const json_t *jtr,
                   struct transcript *tr,
                   json_t **output)
 {
-  // TODO: json_error_t jerror;
   // TODO: struct GNUNET_CRYPTO_EddsaSignature sig;
 
   GNUNET_assert (jtr);
@@ -167,7 +176,7 @@ parse_transcript (const json_t *jtr,
 
 
       if (! json_is_array (prices))
-        // TODO: leak!?
+        // TODO: fix leak!?
         return json_error (output, "no prices found");
 
       tr->k = json_array_size (prices);
@@ -176,7 +185,7 @@ parse_transcript (const json_t *jtr,
       json_array_foreach (prices, idx, val)
       {
         if (! json_is_string (val))
-          // TODO: leak!_
+          // TODO: fix leak!_
           return json_error (output, "prices not strings");
 
         tr->prices[idx] = (char *) json_string_value (val);
@@ -192,7 +201,7 @@ parse_transcript (const json_t *jtr,
 
     bidders = json_object_get (jtr, "bidders");
     if (! bidders || ! json_is_array (bidders))
-      // TODO: leak!_
+      // TODO: fix leak!_
       return json_error (output, "bidders not found");
 
     // TODO: parse bidders as pub keys;
@@ -207,14 +216,14 @@ parse_transcript (const json_t *jtr,
 
     messages = json_object_get (jtr, "transcript");
     if (! json_is_array (messages))
-      // TODO: leak!
+      // TODO: fix leak!
       return json_error (output, "no messages found");
 
 
     nm = json_array_size (messages);
 
     if (nm != (4 * tr->n))
-      // TODO: leak!
+      // TODO: fix leak!
       return json_error (output, "not the right no. of messages found");
   }
 
@@ -229,7 +238,8 @@ parse_transcript (const json_t *jtr,
     if (! json_is_array (winners))
     {
       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                  "winners not provided, continuing without\n");
+                  LOG_PREFIX "winners not provided, continuing without\n");
+      // TODO: fix leakage
       goto CONT;
     }
 
@@ -255,13 +265,118 @@ parse_transcript (const json_t *jtr,
                              spec,
                              (const char**) &error,
                              NULL))
-        // TODO: leak!
+        // TODO: fix leak!
         return json_error (output, "couldn't parse winners");
     }
 
 CONT:
+    // TODO: fix leakages
   }
-  return json_result (output, tr);
+  *output = NULL;
+  return GNUNET_OK;
+}
+
+
+/**
+ * @brief replay an auction using the external program
+ *
+ * @param[in] root The original JSON transcript
+ * @param[in] transcript The transcript object parsed so far
+ * @param[out] result The JSON result from the program
+ * @return GNUNET_OK on success
+ *
+ * TODO: Make this asynchronous (giving out a replay-ID to poll from)?
+ */
+static enum GNUNET_GenericReturnValue
+replay_transcript (const json_t*root,
+                   struct transcript *tr,
+                   json_t **result)
+{
+  struct GNUNET_DISK_PipeHandle *pi;
+  struct GNUNET_DISK_PipeHandle *po;
+  const struct GNUNET_DISK_FileHandle *fd;
+  struct GNUNET_OS_Process *proc;
+
+  pi = GNUNET_DISK_pipe (GNUNET_DISK_PF_BLOCKING_WRITE);
+  po = GNUNET_DISK_pipe (GNUNET_DISK_PF_BLOCKING_READ);
+  proc = GNUNET_OS_start_process (GNUNET_OS_INHERIT_STD_ERR,
+                                  pi, po, NULL,
+                                  replay_program,
+                                  replay_program,
+                                  NULL);
+  if (NULL == proc)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                LOG_PREFIX "couldn't create auction replay program '%s'\n",
+                replay_program);
+
+    return json_error (result, "internal error");
+  }
+
+  // Write original transcript JSON to stdin
+  {
+    ssize_t sz;
+    char *str;
+    size_t str_len;
+
+
+    fd = GNUNET_DISK_pipe_handle (pi, GNUNET_DISK_PIPE_END_WRITE);
+    str = json_dumps (root, JSON_COMPACT);
+    str_len = strlen (str);
+    sz = GNUNET_DISK_file_write (fd,
+                                 str,
+                                 str_len);
+    free (str);
+    if (sz != str_len)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                  LOG_PREFIX "couldn't write all data to replay_program\n");
+    }
+  }
+
+  // Read output from stdout
+  {
+    ssize_t sz;
+    char buf[MAX_RESULT_SIZE];
+    fd = GNUNET_DISK_pipe_handle (po, GNUNET_DISK_PIPE_END_READ);
+
+    sz = GNUNET_DISK_file_read (fd,
+                                buf,
+                                sizeof(buf));
+    if (GNUNET_SYSERR == sz)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                  LOG_PREFIX "couldn't read data from replay_program\n");
+    }
+    else
+    {
+      json_error_t error;
+      json_t *res;
+      res = json_loads (buf,
+                        JSON_DECODE_ANY,
+                        &error);
+
+      if (! res)
+        return json_error (result, error.text);
+
+      *result = json_copy (res);
+      json_decref (res);
+    }
+  }
+
+  if (GNUNET_OK != GNUNET_OS_process_wait (proc))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                LOG_PREFIX "error while launching auction replay program '%s'\n",
+                replay_program);
+
+    json_object_clear (*result);
+    return json_error (result, "internal error");
+  }
+
+
+  // TODO: parse result
+  return GNUNET_OK;
 }
 
 
@@ -338,7 +453,7 @@ auction_http_get_handler (
   /* TODO: return some meta-data about supported version, limits, etc.*/
 
   GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-              "auction_http_get_handler not implemented yet\n");
+              LOG_PREFIX "auction_http_get_handler not implemented yet\n");
 
   return TALER_MHD_reply_with_error (connection,
                                      MHD_HTTP_NOT_IMPLEMENTED,
@@ -359,17 +474,26 @@ auction_http_post_handler (
 {
   struct transcript tr = {};
   enum GNUNET_GenericReturnValue ret;
-  json_t *result;
+  json_t *result1;
+  json_t *result2;
 
-  ret = parse_transcript (root, &tr, &result);
+  ret = parse_transcript (root,
+                          &tr,
+                          &result1);
+  if (GNUNET_OK != ret)
+    return TALER_MHD_reply_json_steal (connection,
+                                       result1,
+                                       MHD_HTTP_BAD_REQUEST);
+  GNUNET_assert (NULL == result1);
 
-  /* TODO */
+  ret = replay_transcript (root,
-  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                           &tr,
-              "auction_http_post_handler not implemented yet\n");
+                           &result2);
 
   return TALER_MHD_reply_json_steal (connection,
-                                     result,
+                                     result2,
-                                     GNUNET_OK == ret? MHD_HTTP_OK :
+                                     GNUNET_OK == ret?
+                                     MHD_HTTP_OK :
                                      MHD_HTTP_BAD_REQUEST);
 }
 
@@ -427,7 +551,7 @@ libtaler_extension_auction_brandt_init (void *arg)
   }
   /* TODO: check if replay_program is actually executable */
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "[auction_brandt] loading... using replay_program '%s'\n",
+              LOG_PREFIX "loading... using replay_program '%s'\n",
               replay_program);
 
   return &TE_auction_brandt;

src/testing/test_exchange_auction.conf

@@ -0,0 +1,159 @@
+# This file is in the public domain.
+#
+
+[PATHS]
+# Persistent data storage for the testcase
+TALER_TEST_HOME = test_exchange_api_home/
+TALER_RUNTIME_DIR = ${TMPDIR:-${TMP:-/tmp}}/${USER:-}/taler-system-runtime/
+
+[taler-exchange-secmod-rsa]
+# Reduce from 1 year to speed up test
+LOOKAHEAD_SIGN = 24 days
+
+[taler-exchange-secmod-eddsa]
+# Reduce from 1 year to speed up test
+LOOKAHEAD_SIGN = 24 days
+# Reduce from 12 weeks to ensure we have multiple
+DURATION = 14 days
+
+[taler]
+# Currency supported by the exchange (can only be one)
+CURRENCY = EUR
+CURRENCY_ROUND_UNIT = EUR:0.01
+
+[auditor]
+BASE_URL = "http://localhost:8083/"
+
+# HTTP port the auditor listens to
+PORT = 8083
+
+[exchange]
+
+TERMS_ETAG = 0
+PRIVACY_ETAG = 0
+
+# HTTP port the exchange listens to
+PORT = 8081
+
+# Master public key used to sign the exchange's various keys
+MASTER_PUBLIC_KEY = 98NJW3CQHZQGQXTY3K85K531XKPAPAVV4Q5V8PYYRR00NJGZWNVG
+
+# How to access our database
+DB = postgres
+
+# Base URL of the exchange. Must be set to a URL where the
+# exchange (or the twister) is actually listening.
+BASE_URL = "http://localhost:8081/"
+
+# How big is an individual shard to be processed
+# by taler-exchange-expire (in time).  It may take
+# this much time for an expired purse to be really
+# cleaned up and the coins refunded.
+EXPIRE_SHARD_SIZE = 300 ms
+
+EXPIRE_IDLE_SLEEP_INTERVAL = 1 s
+
+
+[exchangedb-postgres]
+CONFIG = "postgres:///talercheck"
+
+[auditordb-postgres]
+CONFIG = "postgres:///talercheck"
+
+# Sections starting with "exchange-account-" configure the bank accounts
+# of the exchange.  The "URL" specifies the account in
+# payto://-format.
+[exchange-account-1]
+# What is the URL of our account?
+PAYTO_URI = "payto://x-taler-bank/localhost/42?receiver-name=42"
+# ENABLE_CREDIT = YES
+
+[exchange-accountcredentials-1]
+WIRE_GATEWAY_URL = "http://localhost:9081/42/"
+
+[exchange-account-2]
+# What is the bank account (with the "Taler Bank" demo system)?
+PAYTO_URI = "payto://x-taler-bank/localhost/2?receiver-name=2"
+ENABLE_DEBIT = YES
+ENABLE_CREDIT = YES
+
+[exchange-accountcredentials-2]
+WIRE_GATEWAY_AUTH_METHOD = basic
+USERNAME = Exchange
+PASSWORD = x
+WIRE_GATEWAY_URL = "http://localhost:9081/2/"
+
+[bank]
+HTTP_PORT = 9081
+
+# Enabled extensions
+#[exchange-extension-age_restriction]
+#ENABLED = YES
+# default age groups:
+#AGE_GROUPS = "8:10:12:14:16:18:21"
+
+[exchange-extension-auction_brandt]
+ENABLED = YES
+REPLAY_PROGRAM = "/usr/local/bin/taler-exchange-auction_brandt-replay"
+
+# Sections starting with "coin_" specify which denominations
+# the exchange should support (and their respective fee structure)
+[coin_eur_ct_1]
+value = EUR:0.01
+duration_withdraw = 7 days
+duration_spend = 2 years
+duration_legal = 3 years
+fee_withdraw = EUR:0.00
+fee_deposit = EUR:0.00
+fee_refresh = EUR:0.01
+fee_refund = EUR:0.01
+CIPHER = RSA
+rsa_keysize = 1024
+
+[coin_eur_ct_10]
+value = EUR:0.10
+duration_withdraw = 7 days
+duration_spend = 2 years
+duration_legal = 3 years
+fee_withdraw = EUR:0.01
+fee_deposit = EUR:0.01
+fee_refresh = EUR:0.03
+fee_refund = EUR:0.01
+CIPHER = RSA
+rsa_keysize = 1024
+
+[coin_eur_1]
+value = EUR:1
+duration_withdraw = 7 days
+duration_spend = 2 years
+duration_legal = 3 years
+fee_withdraw = EUR:0.01
+fee_deposit = EUR:0.01
+fee_refresh = EUR:0.03
+fee_refund = EUR:0.01
+CIPHER = RSA
+rsa_keysize = 1024
+
+[coin_eur_5]
+value = EUR:5
+duration_withdraw = 7 days
+duration_spend = 2 years
+duration_legal = 3 years
+fee_withdraw = EUR:0.01
+fee_deposit = EUR:0.01
+fee_refresh = EUR:0.03
+fee_refund = EUR:0.01
+CIPHER = RSA
+rsa_keysize = 1024
+
+[coin_eur_10]
+value = EUR:10
+duration_withdraw = 7 days
+duration_spend = 2 years
+duration_legal = 3 years
+fee_withdraw = EUR:0.01
+fee_deposit = EUR:0.01
+fee_refresh = EUR:0.03
+fee_refund = EUR:0.01
+CIPHER = RSA
+rsa_keysize = 1024