separate util.c and url.c

src/include/taler_crypto_lib.h

@@ -739,7 +739,7 @@ TALER_refresh_get_commitment (struct TALER_RefreshCommitmentP *rc,
 
 /**
  * Compute the hash of the given wire details.   The resulting
- * hash is what is put into the contract.
+ * hash is what is signed by the master key.
  *
  * @param payto_uri bank account
  * @param[out] hc set to the hash
@@ -750,7 +750,7 @@ TALER_exchange_wire_signature_hash (const char *payto_uri,
 
 
 /**
- * Check the signature in @a wire_s.
+ * Check the signature in @a master_sig.
  *
  * @param payto_uri URL that is signed
  * @param master_pub master public key of the exchange
@@ -781,7 +781,8 @@ TALER_exchange_wire_signature_make (const char *payto_uri,
 
 /**
  * Compute the hash of the given wire details.   The resulting
- * hash is what is put into the contract.
+ * @a hc is what will be put into the contract between customer
+ * and merchant for signing by both parties.
  *
  * @param payto_uri bank account
  * @param salt salt used to eliminate brute-force inversion

src/util/Makefile.am

@@ -24,8 +24,12 @@ lib_LTLIBRARIES = \
 
 libtalerutil_la_SOURCES = \
   amount.c \
+  config.c \
   crypto.c \
   crypto_wire.c \
+  getopt.c \
+  payto.c \
+  url.c \
   util.c \
   os_installation.c
 

src/util/amount.c

@@ -22,12 +22,7 @@
  * @author Christian Grothoff
  */
 #include "platform.h"
-#if HAVE_GNUNET_GNUNET_UTIL_LIB_H
 #include "taler_util.h"
-#elif HAVE_GNUNET_GNUNET_UTIL_TALER_WALLET_LIB_H
-#include "taler_util_wallet.h"
-#endif
-#include <gcrypt.h>
 
 /**
  * Maximum legal 'value' for an amount, based on IEEE double (for JavaScript compatibility).

src/util/config.c

@@ -0,0 +1,57 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2020 Taler Systems SA
+
+  TALER 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.
+
+  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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file config.c
+ * @brief configuration parsing functions for Taler-specific data types
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ */
+#include "platform.h"
+#include "taler_util.h"
+
+
+/**
+ * Obtain denomination amount from configuration file.
+ *
+ * @param cfg configuration to use
+ * @param section section of the configuration to access
+ * @param option option of the configuration to access
+ * @param[out] denom set to the amount found in configuration
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
+ */
+int
+TALER_config_get_denom (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                        const char *section,
+                        const char *option,
+                        struct TALER_Amount *denom)
+{
+  char *str;
+
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_string (cfg,
+                                             section,
+                                             option,
+                                             &str))
+    return GNUNET_NO;
+  if (GNUNET_OK != TALER_string_to_amount (str,
+                                           denom))
+  {
+    GNUNET_free (str);
+    return GNUNET_SYSERR;
+  }
+  GNUNET_free (str);
+  return GNUNET_OK;
+}

src/util/crypto.c

@@ -22,13 +22,7 @@
  * @author Christian Grothoff
  */
 #include "platform.h"
-
-#if HAVE_GNUNET_GNUNET_UTIL_TALER_WALLET_LIB_H
-#include "taler_util_wallet.h"
-#endif
-#if HAVE_GNUNET_GNUNET_UTIL_LIB_H
 #include "taler_util.h"
-#endif
 #include <gcrypt.h>
 
 

src/util/crypto_wire.c

@@ -25,7 +25,7 @@
 
 /**
  * Compute the hash of the given wire details. The resulting
- * hash is what is put into the contract.
+ * hash is what is signed by the master key.
  *
  * @param payto_uri bank account
  * @param[out] hc set to the hash
@@ -46,7 +46,7 @@ TALER_exchange_wire_signature_hash (const char *payto_uri,
 
 
 /**
- * Check the signature in @a wire_s.
+ * Check the signature in @a master_sig.
  *
  * @param payto_uri URL that is signed
  * @param master_pub master public key of the exchange
@@ -101,7 +101,8 @@ TALER_exchange_wire_signature_make (const char *payto_uri,
 
 /**
  * Compute the hash of the given wire details.   The resulting
- * hash is what is put into the contract.
+ * @a hc is what will be put into the contract between customer
+ * and merchant for signing by both parties.
  *
  * @param payto_uri bank account
  * @param salt salt used to eliminate brute-force inversion
@@ -126,7 +127,15 @@ TALER_merchant_wire_signature_hash (const char *payto_uri,
 
 
 /**
- * Check the signature in @a merch_sig. (Not yet used anywhere.)
+ * Check the signature in @a merch_sig.
+ * (Not yet used anywhere.)
+ *
+ * Expected to be used if/when we get @a merch_pub signed via
+ * X.509 *and* have a way for the WebEx wallet to check that the
+ * @a merch_pub provided matches that of the X.509 certificate
+ * from the Web site. Until then, @a merch_pub cannto be
+ * validated (no PKI), and hence there is no point in checking
+ * these signatures. (See #5129 and #3946).
  *
  * @param payto_uri URL that is signed
  * @param salt the salt used to salt the @a payto_uri when hashing

src/util/getopt.c

@@ -0,0 +1,87 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2020 Taler Systems SA
+
+  TALER 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.
+
+  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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file getopt.c
+ * @brief Helper functions for parsing Taler-specific command-line arguments
+ * @author Florian Dold
+ */
+#include "platform.h"
+#include "taler_util.h"
+
+
+/**
+ * Set an option with an amount from the command line.  A pointer to
+ * this function should be passed as part of the 'struct
+ * GNUNET_GETOPT_CommandLineOption' array to initialize options of
+ * this type.
+ *
+ * @param ctx command line processing context
+ * @param scls additional closure (will point to the `struct TALER_Amount`)
+ * @param option name of the option
+ * @param value actual value of the option as a string.
+ * @return #GNUNET_OK if parsing the value worked
+ */
+static int
+set_amount (struct GNUNET_GETOPT_CommandLineProcessorContext *ctx,
+            void *scls,
+            const char *option,
+            const char *value)
+{
+  struct TALER_Amount *amount = scls;
+
+  (void) ctx;
+  if (GNUNET_OK !=
+      TALER_string_to_amount (value,
+                              amount))
+  {
+    fprintf (stderr,
+             _ ("Failed to parse amount in option `%s'\n"),
+             option);
+    return GNUNET_SYSERR;
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * Allow user to specify an amount on the command line.
+ *
+ * @param shortName short name of the option
+ * @param name long name of the option
+ * @param argumentHelp help text for the option argument
+ * @param description long help text for the option
+ * @param[out] amount set to the amount specified at the command line
+ */
+struct GNUNET_GETOPT_CommandLineOption
+TALER_getopt_get_amount (char shortName,
+                         const char *name,
+                         const char *argumentHelp,
+                         const char *description,
+                         struct TALER_Amount *amount)
+{
+  struct GNUNET_GETOPT_CommandLineOption clo = {
+    .shortName =  shortName,
+    .name = name,
+    .argumentHelp = argumentHelp,
+    .description = description,
+    .require_argument = 1,
+    .processor = &set_amount,
+    .scls = (void *) amount
+  };
+
+  return clo;
+}

src/util/os_installation.c

@@ -1,6 +1,6 @@
 /*
      This file is part of GNU Taler.
-     Copyright (C) 2016 Inria
+     Copyright (C) 2016 Taler Systems SA
 
      Taler is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
@@ -17,7 +17,6 @@
      Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
      Boston, MA 02110-1301, USA.
 */
-
 /**
  * @file os_installation.c
  * @brief initialize libgnunet OS subsystem for Taler.

src/util/payto.c

@@ -0,0 +1,85 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2019-2020 Taler Systems SA
+
+  TALER 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.
+
+  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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file payto.c
+ * @brief Common utility functions for dealing with payto://-URIs
+ * @author Florian Dold
+ */
+#include "platform.h"
+#include "taler_util.h"
+
+
+/**
+ * Prefix of PAYTO URLs.
+ */
+#define PAYTO "payto://"
+
+
+/**
+ * Obtain the payment method from a @a payto_uri
+ *
+ * @param payto_uri the URL to parse
+ * @return NULL on error (malformed @a payto_uri)
+ */
+char *
+TALER_payto_get_method (const char *payto_uri)
+{
+  const char *start;
+  const char *end;
+
+  if (0 != strncmp (payto_uri,
+                    PAYTO,
+                    strlen (PAYTO)))
+    return NULL;
+  start = &payto_uri[strlen (PAYTO)];
+  end = strchr (start,
+                (unsigned char) '/');
+  if (NULL == end)
+    return NULL;
+  return GNUNET_strndup (start,
+                         end - start);
+}
+
+
+/**
+ * Obtain the account name from a payto URL.
+ *
+ * @param payto an x-taler-bank payto URL
+ * @return only the account name from the @a payto URL, NULL if not an x-taler-bank
+ *   payto URL
+ */
+char *
+TALER_xtalerbank_account_from_payto (const char *payto)
+{
+  const char *beg;
+  const char *end;
+
+  if (0 != strncasecmp (payto,
+                        "payto://x-taler-bank/",
+                        strlen ("payto://x-taler-bank/")))
+    return NULL;
+  beg = strchr (&payto[strlen ("payto://x-taler-bank/")],
+                '/');
+  if (NULL == beg)
+    return NULL;
+  beg++;
+  end = strchr (beg,
+                '?');
+  if (NULL == end)
+    return GNUNET_strdup (beg);
+  return GNUNET_strndup (beg,
+                         end - beg);
+}

src/util/url.c

@@ -0,0 +1,409 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2020 Taler Systems SA
+
+  TALER 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.
+
+  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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file url.c
+ * @brief URL handling utility functions
+ * @author Florian Dold
+ */
+#include "platform.h"
+#include "taler_util.h"
+
+
+/**
+ * Check if a character is reserved and should
+ * be urlencoded.
+ *
+ * @param c character to look at
+ * @return #GNUNET_YES if @a c needs to be urlencoded,
+ *         #GNUNET_NO otherwise
+ */
+static bool
+is_reserved (char c)
+{
+  switch (c)
+  {
+  case '0': case '1': case '2': case '3': case '4':
+  case '5': case '6': case '7': case '8': case '9':
+  case 'a': case 'b': case 'c': case 'd': case 'e':
+  case 'f': case 'g': case 'h': case 'i': case 'j':
+  case 'k': case 'l': case 'm': case 'n': case 'o':
+  case 'p': case 'q': case 'r': case 's': case 't':
+  case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
+  case 'A': case 'B': case 'C': case 'D': case 'E':
+  case 'F': case 'G': case 'H': case 'I': case 'J':
+  case 'K': case 'L': case 'M': case 'N': case 'O':
+  case 'P': case 'Q': case 'R': case 'S': case 'T':
+  case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
+  case '-': case '.': case '_': case '~':
+    return GNUNET_NO;
+  default:
+    break;
+  }
+  return GNUNET_YES;
+}
+
+
+/**
+ * Get the length of a string after it has been
+ * urlencoded.
+ *
+ * @param s the string
+ * @returns the size of the urlencoded @a s
+ */
+static size_t
+urlencode_len (const char *s)
+{
+  size_t len = 0;
+  for (; *s != '\0'; len++, s++)
+    if (GNUNET_YES == is_reserved (*s))
+      len += 2;
+  return len;
+}
+
+
+/**
+ * URL-encode a string according to rfc3986.
+ *
+ * @param buf buffer to write the result to
+ * @param s string to encode
+ */
+static void
+buffer_write_urlencode (struct GNUNET_Buffer *buf,
+                        const char *s)
+{
+  GNUNET_buffer_ensure_remaining (buf, urlencode_len (s) + 1);
+
+  for (size_t i = 0; i < strlen (s); i++)
+  {
+    if (GNUNET_YES == is_reserved (s[i]))
+      GNUNET_buffer_write_fstr (buf, "%%%02X", s[i]);
+    else
+      buf->mem[buf->position++] = s[i];
+  }
+}
+
+
+/**
+ * URL-encode a string according to rfc3986.
+ *
+ * @param s string to encode
+ * @returns the urlencoded string, the caller must free it with #GNUNET_free()
+ */
+char *
+TALER_urlencode (const char *s)
+{
+  struct GNUNET_Buffer buf = { 0 };
+
+  buffer_write_urlencode (&buf, s);
+  return GNUNET_buffer_reap_str (&buf);
+}
+
+
+/**
+ * Make an absolute URL with query parameters.
+ *
+ * @param base_url absolute base URL to use
+ * @param path path of the url
+ * @param ... NULL-terminated key-value pairs (char *) for query parameters,
+ *        the value will be url-encoded
+ * @returns the URL (must be freed with #GNUNET_free) or
+ *          NULL if an error occured.
+ */
+char *
+TALER_url_join (const char *base_url,
+                const char *path,
+                ...)
+{
+  unsigned int iparam = 0;
+  va_list args;
+  struct GNUNET_Buffer buf = { 0 };
+  size_t len;
+
+  GNUNET_assert (NULL != base_url);
+  GNUNET_assert (NULL != path);
+  if (0 == strlen (base_url))
+  {
+    /* base URL can't be empty */
+    GNUNET_break (0);
+    return NULL;
+  }
+  if ('/' != base_url[strlen (base_url) - 1])
+  {
+    /* Must be an actual base URL! */
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Base URL `%s' does not end with '/'\n",
+                base_url);
+    return NULL;
+  }
+  if ('/' == path[0])
+  {
+    /* The path must be relative. */
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Path `%s' is not relative\n",
+                path);
+    return NULL;
+  }
+
+  /* 1st pass: compute length */
+  len = strlen (base_url) + strlen (path) + 1;
+
+  va_start (args, path);
+  while (1)
+  {
+    char *key;
+    char *value;
+    key = va_arg (args, char *);
+    if (NULL == key)
+      break;
+    value = va_arg (args, char *);
+    if (NULL == value)
+      continue;
+    len += urlencode_len (value) + strlen (key) + 2;
+  }
+  va_end (args);
+
+  GNUNET_buffer_prealloc (&buf, len);
+  GNUNET_buffer_write_str (&buf, base_url);
+  GNUNET_buffer_write_str (&buf, path);
+
+  va_start (args, path);
+  while (1)
+  {
+    char *key;
+    char *value;
+
+    key = va_arg (args, char *);
+    if (NULL == key)
+      break;
+    value = va_arg (args, char *);
+    if (NULL == value)
+      continue;
+    GNUNET_buffer_write_str (&buf, (0 == iparam) ? "?" : "&");
+    iparam++;
+    GNUNET_buffer_write_str (&buf, key);
+    GNUNET_buffer_write_str (&buf, "=");
+    buffer_write_urlencode (&buf, value);
+  }
+  va_end (args);
+
+  return GNUNET_buffer_reap_str (&buf);
+}
+
+
+/**
+ * Make an absolute URL for the given parameters.
+ *
+ * @param proto protocol for the URL (typically https)
+ * @param host hostname for the URL
+ * @param prefix prefix for the URL
+ * @param path path for the URL
+ * @param args NULL-terminated key-value pairs (char *) for query parameters,
+ *        the value will be url-encoded
+ * @returns the URL, must be freed with #GNUNET_free
+ */
+char *
+TALER_url_absolute_raw_va (const char *proto,
+                           const char *host,
+                           const char *prefix,
+                           const char *path,
+                           va_list args)
+{
+  struct GNUNET_Buffer buf = { 0 };
+  unsigned int iparam = 0;
+  size_t len = 0;
+  va_list args2;
+
+  len += strlen (proto) + strlen ("://") + strlen (host);
+  len += strlen (prefix) + strlen (path);
+
+  va_copy (args2, args);
+  while (1)
+  {
+    char *key;
+    char *value;
+    key = va_arg (args2, char *);
+    if (NULL == key)
+      break;
+    value = va_arg (args2, char *);
+    if (NULL == value)
+      continue;
+    len += urlencode_len (value) + strlen (key) + 2;
+  }
+  va_end (args2);
+
+  GNUNET_buffer_prealloc (&buf, len);
+
+  GNUNET_buffer_write_str (&buf, proto);
+  GNUNET_buffer_write_str (&buf, "://");
+  GNUNET_buffer_write_str (&buf, host);
+
+  GNUNET_buffer_write_path (&buf, prefix);
+  GNUNET_buffer_write_path (&buf, path);
+
+  va_copy (args2, args);
+  while (1)
+  {
+    char *key;
+    char *value;
+    key = va_arg (args, char *);
+    if (NULL == key)
+      break;
+    value = va_arg (args, char *);
+    if (NULL == value)
+      continue;
+    GNUNET_buffer_write_str (&buf, (0 == iparam) ? "?" : "&");
+    iparam++;
+    GNUNET_buffer_write_str (&buf, key);
+    GNUNET_buffer_write_str (&buf, "=");
+    buffer_write_urlencode (&buf, value);
+  }
+  va_end (args2);
+
+  return GNUNET_buffer_reap_str (&buf);
+}
+
+
+/**
+ * Make an absolute URL for the given parameters.
+ *
+ * @param proto protocol for the URL (typically https)
+ * @param host hostname for the URL
+ * @param prefix prefix for the URL
+ * @param path path for the URL
+ * @param ... NULL-terminated key-value pairs (char *) for query parameters,
+ *        the value will be url-encoded
+ * @returns the URL, must be freed with #GNUNET_free
+ */
+char *
+TALER_url_absolute_raw (const char *proto,
+                        const char *host,
+                        const char *prefix,
+                        const char *path,
+                        ...)
+{
+  char *result;
+  va_list args;
+
+  va_start (args, path);
+  result = TALER_url_absolute_raw_va (proto, host, prefix, path, args);
+  va_end (args);
+  return result;
+}
+
+
+/**
+ * Find out if an MHD connection is using HTTPS (either
+ * directly or via proxy).
+ *
+ * @param connection MHD connection
+ * @returns GNUNET_YES if the MHD connection is using https,
+ *          GNUNET_NO if the MHD connection is using http,
+ *          GNUNET_SYSERR if the connection type couldn't be determined
+ */
+int
+TALER_mhd_is_https (struct MHD_Connection *connection)
+{
+  const union MHD_ConnectionInfo *ci;
+  const union MHD_DaemonInfo *di;
+  const char *forwarded_proto = MHD_lookup_connection_value (connection,
+                                                             MHD_HEADER_KIND,
+                                                             "X-Forwarded-Proto");
+
+  if (NULL != forwarded_proto)
+  {
+    if (0 == strcmp (forwarded_proto, "https"))
+      return GNUNET_YES;
+    if (0 == strcmp (forwarded_proto, "http"))
+      return GNUNET_NO;
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  /* likely not reverse proxy, figure out if we are
+     http by asking MHD */
+  ci = MHD_get_connection_info (connection,
+                                MHD_CONNECTION_INFO_DAEMON);
+  if (NULL == ci)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  di = MHD_get_daemon_info (ci->daemon,
+                            MHD_DAEMON_INFO_FLAGS);
+  if (NULL == di)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  if (0 != (di->flags & MHD_USE_TLS))
+    return GNUNET_YES;
+  return GNUNET_NO;
+}
+
+
+/**
+ * Make an absolute URL for a given MHD connection.
+ *
+ * @param connection the connection to get the URL for
+ * @param path path of the url
+ * @param ... NULL-terminated key-value pairs (char *) for query parameters,
+ *        the value will be url-encoded
+ * @returns the URL, must be freed with #GNUNET_free
+ */
+char *
+TALER_url_absolute_mhd (struct MHD_Connection *connection,
+                        const char *path,
+                        ...)
+{
+  /* By default we assume we're running under HTTPS */
+  const char *proto;
+  const char *host;
+  const char *forwarded_host;
+  const char *prefix;
+  va_list args;
+  char *result;
+
+  if (GNUNET_YES == TALER_mhd_is_https (connection))
+    proto = "https";
+  else
+    proto = "http";
+
+  host = MHD_lookup_connection_value (connection, MHD_HEADER_KIND, "Host");
+  forwarded_host = MHD_lookup_connection_value (connection, MHD_HEADER_KIND,
+                                                "X-Forwarded-Host");
+
+  prefix = MHD_lookup_connection_value (connection, MHD_HEADER_KIND,
+                                        "X-Forwarded-Prefix");
+  if (NULL == prefix)
+    prefix = "";
+
+  if (NULL != forwarded_host)
+    host = forwarded_host;
+
+  if (NULL == host)
+  {
+    /* Should never happen, at last the host header should be defined */
+    GNUNET_break (0);
+    return NULL;
+  }
+
+  va_start (args, path);
+  result = TALER_url_absolute_raw_va (proto, host, prefix, path, args);
+  va_end (args);
+  return result;
+}
+
+
+/* end of url.c */

src/util/util.c

@@ -15,16 +15,13 @@
 */
 /**
  * @file util.c
- * @brief Common utility functions; we might choose to move those to GNUnet at some point
+ * @brief Common utility functions
  * @author Sree Harsha Totakura <sreeharsha@totakura.in>
  * @author Florian Dold
  * @author Benedikt Mueller
  */
-
 #include "platform.h"
-#include "gnunet/gnunet_buffer_lib.h"
 #include "taler_util.h"
-#include <gcrypt.h>
 
 
 /**
@@ -59,547 +56,4 @@ TALER_b2s (const void *buf,
 }
 
 
-/**
- * Obtain denomination amount from configuration file.
- *
- * @param cfg configuration to use
- * @param section section of the configuration to access
- * @param option option of the configuration to access
- * @param[out] denom set to the amount found in configuration
- * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
- */
-int
-TALER_config_get_denom (const struct GNUNET_CONFIGURATION_Handle *cfg,
-                        const char *section,
-                        const char *option,
-                        struct TALER_Amount *denom)
-{
-  char *str;
-
-  if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_string (cfg,
-                                             section,
-                                             option,
-                                             &str))
-    return GNUNET_NO;
-  if (GNUNET_OK != TALER_string_to_amount (str,
-                                           denom))
-  {
-    GNUNET_free (str);
-    return GNUNET_SYSERR;
-  }
-  GNUNET_free (str);
-  return GNUNET_OK;
-}
-
-
-/**
- * Set an option with an amount from the command line.  A pointer to
- * this function should be passed as part of the 'struct
- * GNUNET_GETOPT_CommandLineOption' array to initialize options of
- * this type.
- *
- * @param ctx command line processing context
- * @param scls additional closure (will point to the `struct TALER_Amount`)
- * @param option name of the option
- * @param value actual value of the option as a string.
- * @return #GNUNET_OK if parsing the value worked
- */
-static int
-set_amount (struct GNUNET_GETOPT_CommandLineProcessorContext *ctx,
-            void *scls,
-            const char *option,
-            const char *value)
-{
-  struct TALER_Amount *amount = scls;
-
-  (void) ctx;
-  if (GNUNET_OK !=
-      TALER_string_to_amount (value,
-                              amount))
-  {
-    fprintf (stderr,
-             _ ("Failed to parse amount in option `%s'\n"),
-             option);
-    return GNUNET_SYSERR;
-  }
-
-  return GNUNET_OK;
-}
-
-
-/**
- * Allow user to specify an amount on the command line.
- *
- * @param shortName short name of the option
- * @param name long name of the option
- * @param argumentHelp help text for the option argument
- * @param description long help text for the option
- * @param[out] amount set to the amount specified at the command line
- */
-struct GNUNET_GETOPT_CommandLineOption
-TALER_getopt_get_amount (char shortName,
-                         const char *name,
-                         const char *argumentHelp,
-                         const char *description,
-                         struct TALER_Amount *amount)
-{
-  struct GNUNET_GETOPT_CommandLineOption clo = {
-    .shortName =  shortName,
-    .name = name,
-    .argumentHelp = argumentHelp,
-    .description = description,
-    .require_argument = 1,
-    .processor = &set_amount,
-    .scls = (void *) amount
-  };
-
-  return clo;
-}
-
-
-/**
- * Check if a character is reserved and should
- * be urlencoded.
- *
- * @param c character to look at
- * @return #GNUNET_YES if @a c needs to be urlencoded,
- *         #GNUNET_NO otherwise
- */
-static bool
-is_reserved (char c)
-{
-  switch (c)
-  {
-  case '0': case '1': case '2': case '3': case '4':
-  case '5': case '6': case '7': case '8': case '9':
-  case 'a': case 'b': case 'c': case 'd': case 'e':
-  case 'f': case 'g': case 'h': case 'i': case 'j':
-  case 'k': case 'l': case 'm': case 'n': case 'o':
-  case 'p': case 'q': case 'r': case 's': case 't':
-  case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
-  case 'A': case 'B': case 'C': case 'D': case 'E':
-  case 'F': case 'G': case 'H': case 'I': case 'J':
-  case 'K': case 'L': case 'M': case 'N': case 'O':
-  case 'P': case 'Q': case 'R': case 'S': case 'T':
-  case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
-  case '-': case '.': case '_': case '~':
-    return GNUNET_NO;
-  default:
-    break;
-  }
-  return GNUNET_YES;
-}
-
-
-/**
- * Get the length of a string after it has been
- * urlencoded.
- *
- * @param s the string
- * @returns the size of the urlencoded @a s
- */
-static size_t
-urlencode_len (const char *s)
-{
-  size_t len = 0;
-  for (; *s != '\0'; len++, s++)
-    if (GNUNET_YES == is_reserved (*s))
-      len += 2;
-  return len;
-}
-
-
-/**
- * URL-encode a string according to rfc3986.
- *
- * @param buf buffer to write the result to
- * @param s string to encode
- */
-static void
-buffer_write_urlencode (struct GNUNET_Buffer *buf, const char *s)
-{
-  GNUNET_buffer_ensure_remaining (buf, urlencode_len (s) + 1);
-
-  for (size_t i = 0; i < strlen (s); i++)
-  {
-    if (GNUNET_YES == is_reserved (s[i]))
-      GNUNET_buffer_write_fstr (buf, "%%%02X", s[i]);
-    else
-      buf->mem[buf->position++] = s[i];
-  }
-}
-
-
-/**
- * URL-encode a string according to rfc3986.
- *
- * @param s string to encode
- * @returns the urlencoded string, the caller must free it with GNUNET_free
- */
-char *
-TALER_urlencode (const char *s)
-{
-  struct GNUNET_Buffer buf = { 0 };
-
-  buffer_write_urlencode (&buf, s);
-  return GNUNET_buffer_reap_str (&buf);
-}
-
-
-/**
- * Make an absolute URL with query parameters.
- *
- * @param base_url absolute base URL to use
- * @param path path of the url
- * @param ... NULL-terminated key-value pairs (char *) for query parameters,
- *        the value will be url-encoded
- * @returns the URL (must be freed with #GNUNET_free) or
- *          NULL if an error occured.
- */
-char *
-TALER_url_join (const char *base_url,
-                const char *path,
-                ...)
-{
-  unsigned int iparam = 0;
-  va_list args;
-  struct GNUNET_Buffer buf = { 0 };
-  size_t len;
-
-  GNUNET_assert (NULL != base_url);
-  GNUNET_assert (NULL != path);
-  if (0 == strlen (base_url))
-  {
-    /* base URL can't be empty */
-    GNUNET_break (0);
-    return NULL;
-  }
-  if ('/' != base_url[strlen (base_url) - 1])
-  {
-    /* Must be an actual base URL! */
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Base URL `%s' does not end with '/'\n",
-                base_url);
-    return NULL;
-  }
-  if ('/' == path[0])
-  {
-    /* The path must be relative. */
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Path `%s' is not relative\n",
-                path);
-    return NULL;
-  }
-
-  /* 1st pass: compute length */
-  len = strlen (base_url) + strlen (path) + 1;
-
-  va_start (args, path);
-  while (1)
-  {
-    char *key;
-    char *value;
-    key = va_arg (args, char *);
-    if (NULL == key)
-      break;
-    value = va_arg (args, char *);
-    if (NULL == value)
-      continue;
-    len += urlencode_len (value) + strlen (key) + 2;
-  }
-  va_end (args);
-
-  GNUNET_buffer_prealloc (&buf, len);
-  GNUNET_buffer_write_str (&buf, base_url);
-  GNUNET_buffer_write_str (&buf, path);
-
-  va_start (args, path);
-  while (1)
-  {
-    char *key;
-    char *value;
-
-    key = va_arg (args, char *);
-    if (NULL == key)
-      break;
-    value = va_arg (args, char *);
-    if (NULL == value)
-      continue;
-    GNUNET_buffer_write_str (&buf, (0 == iparam) ? "?" : "&");
-    iparam++;
-    GNUNET_buffer_write_str (&buf, key);
-    GNUNET_buffer_write_str (&buf, "=");
-    buffer_write_urlencode (&buf, value);
-  }
-  va_end (args);
-
-  return GNUNET_buffer_reap_str (&buf);
-}
-
-
-/**
- * Make an absolute URL for the given parameters.
- *
- * @param proto protocol for the URL (typically https)
- * @param host hostname for the URL
- * @param prefix prefix for the URL
- * @param path path for the URL
- * @param args NULL-terminated key-value pairs (char *) for query parameters,
- *        the value will be url-encoded
- * @returns the URL, must be freed with #GNUNET_free
- */
-char *
-TALER_url_absolute_raw_va (const char *proto,
-                           const char *host,
-                           const char *prefix,
-                           const char *path,
-                           va_list args)
-{
-  struct GNUNET_Buffer buf = { 0 };
-  unsigned int iparam = 0;
-  size_t len = 0;
-  va_list args2;
-
-  len += strlen (proto) + strlen ("://") + strlen (host);
-  len += strlen (prefix) + strlen (path);
-
-  va_copy (args2, args);
-  while (1)
-  {
-    char *key;
-    char *value;
-    key = va_arg (args2, char *);
-    if (NULL == key)
-      break;
-    value = va_arg (args2, char *);
-    if (NULL == value)
-      continue;
-    len += urlencode_len (value) + strlen (key) + 2;
-  }
-  va_end (args2);
-
-  GNUNET_buffer_prealloc (&buf, len);
-
-  GNUNET_buffer_write_str (&buf, proto);
-  GNUNET_buffer_write_str (&buf, "://");
-  GNUNET_buffer_write_str (&buf, host);
-
-  GNUNET_buffer_write_path (&buf, prefix);
-  GNUNET_buffer_write_path (&buf, path);
-
-  va_copy (args2, args);
-  while (1)
-  {
-    char *key;
-    char *value;
-    key = va_arg (args, char *);
-    if (NULL == key)
-      break;
-    value = va_arg (args, char *);
-    if (NULL == value)
-      continue;
-    GNUNET_buffer_write_str (&buf, (0 == iparam) ? "?" : "&");
-    iparam++;
-    GNUNET_buffer_write_str (&buf, key);
-    GNUNET_buffer_write_str (&buf, "=");
-    buffer_write_urlencode (&buf, value);
-  }
-  va_end (args2);
-
-  return GNUNET_buffer_reap_str (&buf);
-}
-
-
-/**
- * Make an absolute URL for the given parameters.
- *
- * @param proto protocol for the URL (typically https)
- * @param host hostname for the URL
- * @param prefix prefix for the URL
- * @param path path for the URL
- * @param ... NULL-terminated key-value pairs (char *) for query parameters,
- *        the value will be url-encoded
- * @returns the URL, must be freed with #GNUNET_free
- */
-char *
-TALER_url_absolute_raw (const char *proto,
-                        const char *host,
-                        const char *prefix,
-                        const char *path,
-                        ...)
-{
-  char *result;
-  va_list args;
-
-  va_start (args, path);
-  result = TALER_url_absolute_raw_va (proto, host, prefix, path, args);
-  va_end (args);
-  return result;
-}
-
-
-/**
- * Find out if an MHD connection is using HTTPS (either
- * directly or via proxy).
- *
- * @param connection MHD connection
- * @returns GNUNET_YES if the MHD connection is using https,
- *          GNUNET_NO if the MHD connection is using http,
- *          GNUNET_SYSERR if the connection type couldn't be determined
- */
-int
-TALER_mhd_is_https (struct MHD_Connection *connection)
-{
-  const union MHD_ConnectionInfo *ci;
-  const union MHD_DaemonInfo *di;
-  const char *forwarded_proto = MHD_lookup_connection_value (connection,
-                                                             MHD_HEADER_KIND,
-                                                             "X-Forwarded-Proto");
-
-  if (NULL != forwarded_proto)
-  {
-    if (0 == strcmp (forwarded_proto, "https"))
-      return GNUNET_YES;
-    if (0 == strcmp (forwarded_proto, "http"))
-      return GNUNET_NO;
-    GNUNET_break (0);
-    return GNUNET_SYSERR;
-  }
-  /* likely not reverse proxy, figure out if we are
-     http by asking MHD */
-  ci = MHD_get_connection_info (connection, MHD_CONNECTION_INFO_DAEMON);
-  if (NULL == ci)
-  {
-    GNUNET_break (0);
-    return GNUNET_SYSERR;
-  }
-  di = MHD_get_daemon_info (ci->daemon, MHD_DAEMON_INFO_FLAGS);
-  if (NULL == di)
-  {
-    GNUNET_break (0);
-    return GNUNET_SYSERR;
-  }
-  if (0 != (di->flags & MHD_USE_TLS))
-    return GNUNET_YES;
-  return GNUNET_NO;
-}
-
-
-/**
- * Make an absolute URL for a given MHD connection.
- *
- * @param connection the connection to get the URL for
- * @param path path of the url
- * @param ... NULL-terminated key-value pairs (char *) for query parameters,
- *        the value will be url-encoded
- * @returns the URL, must be freed with #GNUNET_free
- */
-char *
-TALER_url_absolute_mhd (struct MHD_Connection *connection,
-                        const char *path,
-                        ...)
-{
-  /* By default we assume we're running under HTTPS */
-  const char *proto;
-  const char *host;
-  const char *forwarded_host;
-  const char *prefix;
-  va_list args;
-  char *result;
-
-  if (GNUNET_YES == TALER_mhd_is_https (connection))
-    proto = "https";
-  else
-    proto = "http";
-
-  host = MHD_lookup_connection_value (connection, MHD_HEADER_KIND, "Host");
-  forwarded_host = MHD_lookup_connection_value (connection, MHD_HEADER_KIND,
-                                                "X-Forwarded-Host");
-
-  prefix = MHD_lookup_connection_value (connection, MHD_HEADER_KIND,
-                                        "X-Forwarded-Prefix");
-  if (NULL == prefix)
-    prefix = "";
-
-  if (NULL != forwarded_host)
-    host = forwarded_host;
-
-  if (NULL == host)
-  {
-    /* Should never happen, at last the host header should be defined */
-    GNUNET_break (0);
-    return NULL;
-  }
-
-  va_start (args, path);
-  result = TALER_url_absolute_raw_va (proto, host, prefix, path, args);
-  va_end (args);
-  return result;
-}
-
-
-/**
- * Prefix of PAYTO URLs.
- */
-#define PAYTO "payto://"
-
-
-/**
- * Obtain the payment method from a @a payto_uri
- *
- * @param payto_uri the URL to parse
- * @return NULL on error (malformed @a payto_uri)
- */
-char *
-TALER_payto_get_method (const char *payto_uri)
-{
-  const char *start;
-  const char *end;
-
-  if (0 != strncmp (payto_uri,
-                    PAYTO,
-                    strlen (PAYTO)))
-    return NULL;
-  start = &payto_uri[strlen (PAYTO)];
-  end = strchr (start,
-                (unsigned char) '/');
-  if (NULL == end)
-    return NULL;
-  return GNUNET_strndup (start,
-                         end - start);
-}
-
-
-/**
- * Obtain the account name from a payto URL.
- *
- * @param payto an x-taler-bank payto URL
- * @return only the account name from the @a payto URL, NULL if not an x-taler-bank
- *   payto URL
- */
-char *
-TALER_xtalerbank_account_from_payto (const char *payto)
-{
-  const char *beg;
-  const char *end;
-
-  if (0 != strncasecmp (payto,
-                        "payto://x-taler-bank/",
-                        strlen ("payto://x-taler-bank/")))
-    return NULL;
-  beg = strchr (&payto[strlen ("payto://x-taler-bank/")],
-                '/');
-  if (NULL == beg)
-    return NULL;
-  beg++;
-  end = strchr (beg,
-                '?');
-  if (NULL == end)
-    return GNUNET_strdup (beg);
-  return GNUNET_strndup (beg,
-                         end - beg);
-}
-
-
 /* end of util.c */