fs_uri.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2003--2014 GNUnet e.V.

     GNUnet 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 of the License,
     or (at your option) any later version.

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

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

     SPDX-License-Identifier: AGPL3.0-or-later
 */

#include "platform.h"
#include "gnunet_fs_service.h"
#include "gnunet_signatures.h"
#include "fs_api.h"
#include <unitypes.h>
#include <unicase.h>
#include <uniconv.h>
#include <unistr.h>
#include <unistdio.h>


int
GNUNET_FS_uri_to_key(const struct GNUNET_FS_Uri *uri,
                     struct GNUNET_HashCode *key)
{
  switch (uri->type)
    {
    case GNUNET_FS_URI_CHK:
      *key = uri->data.chk.chk.query;
      return GNUNET_OK;

    case GNUNET_FS_URI_SKS:
      GNUNET_CRYPTO_hash(uri->data.sks.identifier,
                         strlen(uri->data.sks.identifier),
                         key);
      return GNUNET_OK;

    case GNUNET_FS_URI_KSK:
      if (uri->data.ksk.keywordCount > 0)
        {
          GNUNET_CRYPTO_hash(uri->data.ksk.keywords[0],
                             strlen(uri->data.ksk.keywords[0]),
                             key);
          return GNUNET_OK;
        }
      else
        {
          memset(key, 0, sizeof(struct GNUNET_HashCode));
          return GNUNET_SYSERR;
        }
      break;

    case GNUNET_FS_URI_LOC:
      GNUNET_CRYPTO_hash(&uri->data.loc.fi,
                         sizeof(struct FileIdentifier) +
                         sizeof(struct GNUNET_PeerIdentity),
                         key);
      return GNUNET_OK;

    default:
      memset(key, 0, sizeof(struct GNUNET_HashCode));
      return GNUNET_SYSERR;
    }
}


char *
GNUNET_FS_uri_ksk_to_string_fancy(const struct GNUNET_FS_Uri *uri)
{
  size_t n;
  char *ret;
  unsigned int i;
  const char *keyword;
  char **keywords;
  unsigned int keywordCount;

  if ((NULL == uri) || (GNUNET_FS_URI_KSK != uri->type))
    {
      GNUNET_break(0);
      return NULL;
    }
  keywords = uri->data.ksk.keywords;
  keywordCount = uri->data.ksk.keywordCount;
  n = keywordCount + 1;
  for (i = 0; i < keywordCount; i++)
    {
      keyword = keywords[i];
      n += strlen(keyword) - 1;
      if (NULL != strstr(&keyword[1], " "))
        n += 2;
      if (keyword[0] == '+')
        n++;
    }
  ret = GNUNET_malloc(n);
  strcpy(ret, "");
  for (i = 0; i < keywordCount; i++)
    {
      keyword = keywords[i];
      if (NULL != strstr(&keyword[1], " "))
        {
          strcat(ret, "\"");
          if (keyword[0] == '+')
            strcat(ret, keyword);
          else
            strcat(ret, &keyword[1]);
          strcat(ret, "\"");
        }
      else
        {
          if (keyword[0] == '+')
            strcat(ret, keyword);
          else
            strcat(ret, &keyword[1]);
        }
      strcat(ret, " ");
    }
  return ret;
}


static char *
percent_decode_keyword(const char *in, char **emsg)
{
  char *out;
  char *ret;
  unsigned int rpos;
  unsigned int wpos;
  unsigned int hx;

  out = GNUNET_strdup(in);
  rpos = 0;
  wpos = 0;
  while (out[rpos] != '\0')
    {
      if (out[rpos] == '%')
        {
          if (1 != sscanf(&out[rpos + 1], "%2X", &hx))
            {
              GNUNET_free(out);
              *emsg = GNUNET_strdup(
                _(/* xgettext:no-c-format */
                  "Malformed KSK URI (`%' must be followed by HEX number)"));
              return NULL;
            }
          rpos += 3;
          if (hx == '"')
            continue; /* skip double quote */
          out[wpos++] = (char)hx;
        }
      else
        {
          out[wpos++] = out[rpos++];
        }
    }
  out[wpos] = '\0';
  if (out[0] == '+')
    {
      ret = GNUNET_strdup(out);
    }
  else
    {
      /* need to prefix with space */
      ret = GNUNET_malloc(strlen(out) + 2);
      strcpy(ret, " ");
      strcat(ret, out);
    }
  GNUNET_free(out);
  return ret;
}

#define GNUNET_FS_URI_KSK_PREFIX GNUNET_FS_URI_PREFIX GNUNET_FS_URI_KSK_INFIX

static struct GNUNET_FS_Uri *
uri_ksk_parse(const char *s, char **emsg)
{
  struct GNUNET_FS_Uri *ret;
  char **keywords;
  unsigned int pos;
  int max;
  int iret;
  int i;
  size_t slen;
  char *dup;
  int saw_quote;

  slen = strlen(s);
  pos = strlen(GNUNET_FS_URI_KSK_PREFIX);
  if ((slen <= pos) || (0 != strncmp(s, GNUNET_FS_URI_KSK_PREFIX, pos)))
    return NULL; /* not KSK URI */
  if ((s[slen - 1] == '+') || (s[pos] == '+'))
    {
      *emsg =
        GNUNET_strdup(_("Malformed KSK URI (must not begin or end with `+')"));
      return NULL;
    }
  max = 1;
  saw_quote = 0;
  for (i = pos; i < slen; i++)
    {
      if ((s[i] == '%') && (&s[i] == strstr(&s[i], "%22")))
        {
          saw_quote = (saw_quote + 1) % 2;
          i += 3;
          continue;
        }
      if ((s[i] == '+') && (saw_quote == 0))
        {
          max++;
          if (s[i - 1] == '+')
            {
              *emsg = GNUNET_strdup(_("Malformed KSK URI (`++' not allowed)"));
              return NULL;
            }
        }
    }
  if (saw_quote == 1)
    {
      *emsg = GNUNET_strdup(_("Malformed KSK URI (quotes not balanced)"));
      return NULL;
    }
  iret = max;
  dup = GNUNET_strdup(s);
  keywords = GNUNET_new_array(max, char *);
  for (i = slen - 1; i >= (int)pos; i--)
    {
      if ((s[i] == '%') && (&s[i] == strstr(&s[i], "%22")))
        {
          saw_quote = (saw_quote + 1) % 2;
          continue;
        }
      if ((dup[i] == '+') && (saw_quote == 0))
        {
          keywords[--max] = percent_decode_keyword(&dup[i + 1], emsg);
          if (NULL == keywords[max])
            goto CLEANUP;
          dup[i] = '\0';
        }
    }
  keywords[--max] = percent_decode_keyword(&dup[pos], emsg);
  if (NULL == keywords[max])
    goto CLEANUP;
  GNUNET_assert(0 == max);
  GNUNET_free(dup);
  ret = GNUNET_new(struct GNUNET_FS_Uri);
  ret->type = GNUNET_FS_URI_KSK;
  ret->data.ksk.keywordCount = iret;
  ret->data.ksk.keywords = keywords;
  return ret;
CLEANUP:
  for (i = 0; i < max; i++)
    GNUNET_free_non_null(keywords[i]);
  GNUNET_free(keywords);
  GNUNET_free(dup);
  return NULL;
}


#define GNUNET_FS_URI_SKS_PREFIX GNUNET_FS_URI_PREFIX GNUNET_FS_URI_SKS_INFIX

static struct GNUNET_FS_Uri *
uri_sks_parse(const char *s, char **emsg)
{
  struct GNUNET_FS_Uri *ret;
  struct GNUNET_CRYPTO_EcdsaPublicKey ns;
  size_t pos;
  char *end;

  pos = strlen(GNUNET_FS_URI_SKS_PREFIX);
  if ((strlen(s) <= pos) || (0 != strncmp(s, GNUNET_FS_URI_SKS_PREFIX, pos)))
    return NULL; /* not an SKS URI */
  end = strchr(&s[pos], '/');
  if ((NULL == end) ||
      (GNUNET_OK != GNUNET_STRINGS_string_to_data(&s[pos],
                                                  end - &s[pos],
                                                  &ns,
                                                  sizeof(ns))))
    {
      *emsg = GNUNET_strdup(_("Malformed SKS URI (wrong syntax)"));
      return NULL; /* malformed */
    }
  end++; /* skip over '/' */
  ret = GNUNET_new(struct GNUNET_FS_Uri);
  ret->type = GNUNET_FS_URI_SKS;
  ret->data.sks.ns = ns;
  ret->data.sks.identifier = GNUNET_strdup(end);
  return ret;
}

#define GNUNET_FS_URI_CHK_PREFIX GNUNET_FS_URI_PREFIX GNUNET_FS_URI_CHK_INFIX


static struct GNUNET_FS_Uri *
uri_chk_parse(const char *s, char **emsg)
{
  struct GNUNET_FS_Uri *ret;
  struct FileIdentifier fi;
  unsigned int pos;
  unsigned long long flen;
  size_t slen;
  char h1[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded)];
  char h2[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded)];

  slen = strlen(s);
  pos = strlen(GNUNET_FS_URI_CHK_PREFIX);
  if ((slen < pos + 2 * sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) + 1) ||
      (0 != strncmp(s, GNUNET_FS_URI_CHK_PREFIX, pos)))
    return NULL; /* not a CHK URI */
  if ((s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) - 1] != '.') ||
      (s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) * 2 - 1] != '.'))
    {
      *emsg = GNUNET_strdup(_("Malformed CHK URI (wrong syntax)"));
      return NULL;
    }
  GNUNET_memcpy(h1, &s[pos], sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded));
  h1[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) - 1] = '\0';
  GNUNET_memcpy(h2,
                &s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded)],
                sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded));
  h2[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) - 1] = '\0';

  if ((GNUNET_OK != GNUNET_CRYPTO_hash_from_string(h1, &fi.chk.key)) ||
      (GNUNET_OK != GNUNET_CRYPTO_hash_from_string(h2, &fi.chk.query)) ||
      (1 !=
       sscanf(&s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) * 2],
              "%llu",
              &flen)))
    {
      *emsg = GNUNET_strdup(_("Malformed CHK URI (failed to decode CHK)"));
      return NULL;
    }
  fi.file_length = GNUNET_htonll(flen);
  ret = GNUNET_new(struct GNUNET_FS_Uri);
  ret->type = GNUNET_FS_URI_CHK;
  ret->data.chk = fi;
  return ret;
}


GNUNET_NETWORK_STRUCT_BEGIN
struct LocUriAssembly {
  struct GNUNET_CRYPTO_EccSignaturePurpose purpose;

  struct GNUNET_TIME_AbsoluteNBO exptime;

  struct FileIdentifier fi;

  struct GNUNET_PeerIdentity peer;
};
GNUNET_NETWORK_STRUCT_END


#define GNUNET_FS_URI_LOC_PREFIX GNUNET_FS_URI_PREFIX GNUNET_FS_URI_LOC_INFIX

#define SIGNATURE_ASCII_LENGTH 103

static struct GNUNET_FS_Uri *
uri_loc_parse(const char *s, char **emsg)
{
  struct GNUNET_FS_Uri *uri;
  char h1[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded)];
  char h2[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded)];
  unsigned int pos;
  unsigned int npos;
  unsigned long long exptime;
  unsigned long long flen;
  struct GNUNET_TIME_Absolute et;
  struct GNUNET_CRYPTO_EddsaSignature sig;
  struct LocUriAssembly ass;
  size_t slen;

  slen = strlen(s);
  pos = strlen(GNUNET_FS_URI_LOC_PREFIX);
  if ((slen < pos + 2 * sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) + 1) ||
      (0 != strncmp(s, GNUNET_FS_URI_LOC_PREFIX, pos)))
    return NULL; /* not a LOC URI */
  if ((s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) - 1] != '.') ||
      (s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) * 2 - 1] != '.'))
    {
      *emsg = GNUNET_strdup(_("LOC URI malformed (wrong syntax)"));
      return NULL;
    }
  GNUNET_memcpy(h1, &s[pos], sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded));
  h1[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) - 1] = '\0';
  GNUNET_memcpy(h2,
                &s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded)],
                sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded));
  h2[sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) - 1] = '\0';

  if ((GNUNET_OK != GNUNET_CRYPTO_hash_from_string(h1, &ass.fi.chk.key)) ||
      (GNUNET_OK != GNUNET_CRYPTO_hash_from_string(h2, &ass.fi.chk.query)) ||
      (1 !=
       sscanf(&s[pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) * 2],
              "%llu",
              &flen)))
    {
      *emsg = GNUNET_strdup(_("LOC URI malformed (no CHK)"));
      return NULL;
    }
  ass.fi.file_length = GNUNET_htonll(flen);

  npos = pos + sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) * 2;
  while ((s[npos] != '\0') && (s[npos] != '.'))
    npos++;
  if (s[npos] == '\0')
    {
      *emsg = GNUNET_strdup(_("LOC URI malformed (missing LOC)"));
      goto ERR;
    }
  npos++;
  if ((strlen(&s[npos]) <= GNUNET_CRYPTO_PKEY_ASCII_LENGTH + 1) ||
      ('.' != s[npos + GNUNET_CRYPTO_PKEY_ASCII_LENGTH]))
    {
      *emsg =
        GNUNET_strdup(_("LOC URI malformed (wrong syntax for public key)"));
    }
  if (
    GNUNET_OK !=
    GNUNET_CRYPTO_eddsa_public_key_from_string(&s[npos],
                                               GNUNET_CRYPTO_PKEY_ASCII_LENGTH,
                                               &ass.peer.public_key))
    {
      *emsg =
        GNUNET_strdup(_("LOC URI malformed (could not decode public key)"));
      goto ERR;
    }
  npos += GNUNET_CRYPTO_PKEY_ASCII_LENGTH;
  if (s[npos++] != '.')
    {
      *emsg = GNUNET_strdup(_("LOC URI malformed (could not find signature)"));
      goto ERR;
    }
  if ((strlen(&s[npos]) <= SIGNATURE_ASCII_LENGTH + 1) ||
      ('.' != s[npos + SIGNATURE_ASCII_LENGTH]))
    {
      *emsg =
        GNUNET_strdup(_("LOC URI malformed (wrong syntax for signature)"));
      goto ERR;
    }
  if (GNUNET_OK !=
      GNUNET_STRINGS_string_to_data(&s[npos],
                                    SIGNATURE_ASCII_LENGTH,
                                    &sig,
                                    sizeof(
                                      struct GNUNET_CRYPTO_EddsaSignature)))
    {
      *emsg =
        GNUNET_strdup(_("LOC URI malformed (could not decode signature)"));
      goto ERR;
    }
  npos += SIGNATURE_ASCII_LENGTH;
  if (s[npos++] != '.')
    {
      *emsg = GNUNET_strdup(
        _("LOC URI malformed (wrong syntax for expiration time)"));
      goto ERR;
    }
  if (1 != sscanf(&s[npos], "%llu", &exptime))
    {
      *emsg =
        GNUNET_strdup(_("LOC URI malformed (could not parse expiration time)"));
      goto ERR;
    }
  ass.purpose.size = htonl(sizeof(struct LocUriAssembly));
  ass.purpose.purpose = htonl(GNUNET_SIGNATURE_PURPOSE_PEER_PLACEMENT);
  et.abs_value_us = exptime * 1000LL * 1000LL;
  ass.exptime = GNUNET_TIME_absolute_hton(et);
  if (GNUNET_OK !=
      GNUNET_CRYPTO_eddsa_verify(GNUNET_SIGNATURE_PURPOSE_PEER_PLACEMENT,
                                 &ass.purpose,
                                 &sig,
                                 &ass.peer.public_key))
    {
      *emsg =
        GNUNET_strdup(_("LOC URI malformed (signature failed validation)"));
      goto ERR;
    }
  uri = GNUNET_new(struct GNUNET_FS_Uri);
  uri->type = GNUNET_FS_URI_LOC;
  uri->data.loc.fi = ass.fi;
  uri->data.loc.peer = ass.peer;
  uri->data.loc.expirationTime = et;
  uri->data.loc.contentSignature = sig;

  return uri;
ERR:
  return NULL;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_parse(const char *uri, char **emsg)
{
  struct GNUNET_FS_Uri *ret;
  char *msg;

  if (NULL == uri)
    {
      GNUNET_break(0);
      if (NULL != emsg)
        *emsg = GNUNET_strdup(_("invalid argument"));
      return NULL;
    }
  if (NULL == emsg)
    emsg = &msg;
  *emsg = NULL;
  if ((NULL != (ret = uri_chk_parse(uri, emsg))) ||
      (NULL != (ret = uri_ksk_parse(uri, emsg))) ||
      (NULL != (ret = uri_sks_parse(uri, emsg))) ||
      (NULL != (ret = uri_loc_parse(uri, emsg))))
    return ret;
  if (NULL == *emsg)
    *emsg = GNUNET_strdup(_("Unrecognized URI type"));
  if (emsg == &msg)
    GNUNET_free(msg);
  return NULL;
}


void
GNUNET_FS_uri_destroy(struct GNUNET_FS_Uri *uri)
{
  unsigned int i;

  switch (uri->type)
    {
    case GNUNET_FS_URI_KSK:
      for (i = 0; i < uri->data.ksk.keywordCount; i++)
        GNUNET_free(uri->data.ksk.keywords[i]);
      GNUNET_array_grow(uri->data.ksk.keywords, uri->data.ksk.keywordCount, 0);
      break;

    case GNUNET_FS_URI_SKS:
      GNUNET_free(uri->data.sks.identifier);
      break;

    case GNUNET_FS_URI_LOC:
      break;

    default:
      /* do nothing */
      break;
    }
  GNUNET_free(uri);
}


unsigned int
GNUNET_FS_uri_ksk_get_keyword_count(const struct GNUNET_FS_Uri *uri)
{
  if (uri->type != GNUNET_FS_URI_KSK)
    return 0;
  return uri->data.ksk.keywordCount;
}


int
GNUNET_FS_uri_ksk_get_keywords(const struct GNUNET_FS_Uri *uri,
                               GNUNET_FS_KeywordIterator iterator,
                               void *iterator_cls)
{
  unsigned int i;
  char *keyword;

  if (uri->type != GNUNET_FS_URI_KSK)
    return -1;
  if (NULL == iterator)
    return uri->data.ksk.keywordCount;
  for (i = 0; i < uri->data.ksk.keywordCount; i++)
    {
      keyword = uri->data.ksk.keywords[i];
      /* first character of keyword indicates
       * if it is mandatory or not */
      if (GNUNET_OK != iterator(iterator_cls, &keyword[1], keyword[0] == '+'))
        return i;
    }
  return i;
}


void
GNUNET_FS_uri_ksk_add_keyword(struct GNUNET_FS_Uri *uri,
                              const char *keyword,
                              int is_mandatory)
{
  unsigned int i;
  const char *old;
  char *n;

  GNUNET_assert(uri->type == GNUNET_FS_URI_KSK);
  for (i = 0; i < uri->data.ksk.keywordCount; i++)
    {
      old = uri->data.ksk.keywords[i];
      if (0 == strcmp(&old[1], keyword))
        return;
    }
  GNUNET_asprintf(&n, is_mandatory ? "+%s" : " %s", keyword);
  GNUNET_array_append(uri->data.ksk.keywords, uri->data.ksk.keywordCount, n);
}


void
GNUNET_FS_uri_ksk_remove_keyword(struct GNUNET_FS_Uri *uri,
                                 const char *keyword)
{
  unsigned int i;
  char *old;

  GNUNET_assert(uri->type == GNUNET_FS_URI_KSK);
  for (i = 0; i < uri->data.ksk.keywordCount; i++)
    {
      old = uri->data.ksk.keywords[i];
      if (0 == strcmp(&old[1], keyword))
        {
          uri->data.ksk.keywords[i] =
            uri->data.ksk.keywords[uri->data.ksk.keywordCount - 1];
          GNUNET_array_grow(uri->data.ksk.keywords,
                            uri->data.ksk.keywordCount,
                            uri->data.ksk.keywordCount - 1);
          GNUNET_free(old);
          return;
        }
    }
}


int
GNUNET_FS_uri_loc_get_peer_identity(const struct GNUNET_FS_Uri *uri,
                                    struct GNUNET_PeerIdentity *peer)
{
  if (uri->type != GNUNET_FS_URI_LOC)
    return GNUNET_SYSERR;
  *peer = uri->data.loc.peer;
  return GNUNET_OK;
}


struct GNUNET_TIME_Absolute
GNUNET_FS_uri_loc_get_expiration(const struct GNUNET_FS_Uri *uri)
{
  GNUNET_assert(uri->type == GNUNET_FS_URI_LOC);
  return uri->data.loc.expirationTime;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_loc_get_uri(const struct GNUNET_FS_Uri *uri)
{
  struct GNUNET_FS_Uri *ret;

  if (uri->type != GNUNET_FS_URI_LOC)
    return NULL;
  ret = GNUNET_new(struct GNUNET_FS_Uri);
  ret->type = GNUNET_FS_URI_CHK;
  ret->data.chk = uri->data.loc.fi;
  return ret;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_loc_create(const struct GNUNET_FS_Uri *base_uri,
                         const struct GNUNET_CRYPTO_EddsaPrivateKey *sign_key,
                         struct GNUNET_TIME_Absolute expiration_time)
{
  struct GNUNET_FS_Uri *uri;
  struct GNUNET_CRYPTO_EddsaPublicKey my_public_key;
  struct LocUriAssembly ass;
  struct GNUNET_TIME_Absolute et;

  if (GNUNET_FS_URI_CHK != base_uri->type)
    return NULL;
  /* we round expiration time to full seconds for SKS URIs */
  et.abs_value_us = (expiration_time.abs_value_us / 1000000LL) * 1000000LL;
  GNUNET_CRYPTO_eddsa_key_get_public(sign_key, &my_public_key);
  ass.purpose.size = htonl(sizeof(struct LocUriAssembly));
  ass.purpose.purpose = htonl(GNUNET_SIGNATURE_PURPOSE_PEER_PLACEMENT);
  ass.exptime = GNUNET_TIME_absolute_hton(et);
  ass.fi = base_uri->data.chk;
  ass.peer.public_key = my_public_key;
  uri = GNUNET_new(struct GNUNET_FS_Uri);
  uri->type = GNUNET_FS_URI_LOC;
  uri->data.loc.fi = base_uri->data.chk;
  uri->data.loc.expirationTime = et;
  uri->data.loc.peer.public_key = my_public_key;
  GNUNET_assert(GNUNET_OK ==
                GNUNET_CRYPTO_eddsa_sign(sign_key,
                                         &ass.purpose,
                                         &uri->data.loc.contentSignature));
  return uri;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_sks_create(const struct GNUNET_CRYPTO_EcdsaPublicKey *ns,
                         const char *id)
{
  struct GNUNET_FS_Uri *ns_uri;

  ns_uri = GNUNET_new(struct GNUNET_FS_Uri);
  ns_uri->type = GNUNET_FS_URI_SKS;
  ns_uri->data.sks.ns = *ns;
  ns_uri->data.sks.identifier = GNUNET_strdup(id);
  return ns_uri;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_ksk_merge(const struct GNUNET_FS_Uri *u1,
                        const struct GNUNET_FS_Uri *u2)
{
  struct GNUNET_FS_Uri *ret;
  unsigned int kc;
  unsigned int i;
  unsigned int j;
  int found;
  const char *kp;
  char **kl;

  if ((u1 == NULL) && (u2 == NULL))
    return NULL;
  if (u1 == NULL)
    return GNUNET_FS_uri_dup(u2);
  if (u2 == NULL)
    return GNUNET_FS_uri_dup(u1);
  if ((u1->type != GNUNET_FS_URI_KSK) || (u2->type != GNUNET_FS_URI_KSK))
    {
      GNUNET_break(0);
      return NULL;
    }
  kc = u1->data.ksk.keywordCount;
  kl = GNUNET_new_array(kc + u2->data.ksk.keywordCount, char *);
  for (i = 0; i < u1->data.ksk.keywordCount; i++)
    kl[i] = GNUNET_strdup(u1->data.ksk.keywords[i]);
  for (i = 0; i < u2->data.ksk.keywordCount; i++)
    {
      kp = u2->data.ksk.keywords[i];
      found = 0;
      for (j = 0; j < u1->data.ksk.keywordCount; j++)
        if (0 == strcmp(kp + 1, kl[j] + 1))
          {
            found = 1;
            if (kp[0] == '+')
              kl[j][0] = '+';
            break;
          }
      if (0 == found)
        kl[kc++] = GNUNET_strdup(kp);
    }
  ret = GNUNET_new(struct GNUNET_FS_Uri);
  ret->type = GNUNET_FS_URI_KSK;
  ret->data.ksk.keywordCount = kc;
  ret->data.ksk.keywords = kl;
  return ret;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_dup(const struct GNUNET_FS_Uri *uri)
{
  struct GNUNET_FS_Uri *ret;
  unsigned int i;

  if (uri == NULL)
    return NULL;
  ret = GNUNET_new(struct GNUNET_FS_Uri);
  GNUNET_memcpy(ret, uri, sizeof(struct GNUNET_FS_Uri));
  switch (ret->type)
    {
    case GNUNET_FS_URI_KSK:
      if (ret->data.ksk.keywordCount >=
          GNUNET_MAX_MALLOC_CHECKED / sizeof(char *))
        {
          GNUNET_break(0);
          GNUNET_free(ret);
          return NULL;
        }
      if (ret->data.ksk.keywordCount > 0)
        {
          ret->data.ksk.keywords =
            GNUNET_new_array(ret->data.ksk.keywordCount, char *);
          for (i = 0; i < ret->data.ksk.keywordCount; i++)
            ret->data.ksk.keywords[i] = GNUNET_strdup(uri->data.ksk.keywords[i]);
        }
      else
        ret->data.ksk.keywords = NULL; /* just to be sure */
      break;

    case GNUNET_FS_URI_SKS:
      ret->data.sks.identifier = GNUNET_strdup(uri->data.sks.identifier);
      break;

    case GNUNET_FS_URI_LOC:
      break;

    default:
      break;
    }
  return ret;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_ksk_create(const char *keywords, char **emsg)
{
  char **keywordarr;
  unsigned int num_Words;
  int inWord;
  char *pos;
  struct GNUNET_FS_Uri *uri;
  char *searchString;
  int saw_quote;

  if (keywords == NULL)
    {
      *emsg = GNUNET_strdup(_("No keywords specified!\n"));
      GNUNET_break(0);
      return NULL;
    }
  searchString = GNUNET_strdup(keywords);
  num_Words = 0;
  inWord = 0;
  saw_quote = 0;
  pos = searchString;
  while ('\0' != *pos)
    {
      if ((saw_quote == 0) && (isspace((unsigned char)*pos)))
        {
          inWord = 0;
        }
      else if (0 == inWord)
        {
          inWord = 1;
          ++num_Words;
        }
      if ('"' == *pos)
        saw_quote = (saw_quote + 1) % 2;
      pos++;
    }
  if (num_Words == 0)
    {
      GNUNET_free(searchString);
      *emsg = GNUNET_strdup(_("No keywords specified!\n"));
      return NULL;
    }
  if (saw_quote != 0)
    {
      GNUNET_free(searchString);
      *emsg = GNUNET_strdup(_("Number of double-quotes not balanced!\n"));
      return NULL;
    }
  keywordarr = GNUNET_new_array(num_Words, char *);
  num_Words = 0;
  inWord = 0;
  pos = searchString;
  while ('\0' != *pos)
    {
      if ((saw_quote == 0) && (isspace((unsigned char)*pos)))
        {
          inWord = 0;
          *pos = '\0';
        }
      else if (0 == inWord)
        {
          keywordarr[num_Words] = pos;
          inWord = 1;
          ++num_Words;
        }
      if ('"' == *pos)
        saw_quote = (saw_quote + 1) % 2;
      pos++;
    }
  uri =
    GNUNET_FS_uri_ksk_create_from_args(num_Words, (const char **)keywordarr);
  GNUNET_free(keywordarr);
  GNUNET_free(searchString);
  return uri;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_ksk_create_from_args(unsigned int argc, const char **argv)
{
  unsigned int i;
  struct GNUNET_FS_Uri *uri;
  const char *keyword;
  char *val;
  const char *r;
  char *w;
  char *emsg;

  if (argc == 0)
    return NULL;
  /* allow URI to be given as one and only keyword and
   * handle accordingly */
  emsg = NULL;
  if ((argc == 1) && (strlen(argv[0]) > strlen(GNUNET_FS_URI_PREFIX)) &&
      (0 == strncmp(argv[0],
                    GNUNET_FS_URI_PREFIX,
                    strlen(GNUNET_FS_URI_PREFIX))) &&
      (NULL != (uri = GNUNET_FS_uri_parse(argv[0], &emsg))))
    return uri;
  GNUNET_free_non_null(emsg);
  uri = GNUNET_new(struct GNUNET_FS_Uri);
  uri->type = GNUNET_FS_URI_KSK;
  uri->data.ksk.keywordCount = argc;
  uri->data.ksk.keywords = GNUNET_new_array(argc, char *);
  for (i = 0; i < argc; i++)
    {
      keyword = argv[i];
      if (keyword[0] == '+')
        val = GNUNET_strdup(keyword);
      else
        GNUNET_asprintf(&val, " %s", keyword);
      r = val;
      w = val;
      while ('\0' != *r)
        {
          if ('"' == *r)
            r++;
          else
            *(w++) = *(r++);
        }
      *w = '\0';
      uri->data.ksk.keywords[i] = val;
    }
  return uri;
}


int
GNUNET_FS_uri_test_equal(const struct GNUNET_FS_Uri *u1,
                         const struct GNUNET_FS_Uri *u2)
{
  int ret;
  unsigned int i;
  unsigned int j;

  GNUNET_assert(u1 != NULL);
  GNUNET_assert(u2 != NULL);
  if (u1->type != u2->type)
    return GNUNET_NO;
  switch (u1->type)
    {
    case GNUNET_FS_URI_CHK:
      if (0 ==
          memcmp(&u1->data.chk, &u2->data.chk, sizeof(struct FileIdentifier)))
        return GNUNET_YES;
      return GNUNET_NO;

    case GNUNET_FS_URI_SKS:
      if ((0 == memcmp(&u1->data.sks.ns,
                       &u2->data.sks.ns,
                       sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey))) &&
          (0 == strcmp(u1->data.sks.identifier, u2->data.sks.identifier)))

        return GNUNET_YES;
      return GNUNET_NO;

    case GNUNET_FS_URI_KSK:
      if (u1->data.ksk.keywordCount != u2->data.ksk.keywordCount)
        return GNUNET_NO;
      for (i = 0; i < u1->data.ksk.keywordCount; i++)
        {
          ret = GNUNET_NO;
          for (j = 0; j < u2->data.ksk.keywordCount; j++)
            {
              if (0 == strcmp(u1->data.ksk.keywords[i], u2->data.ksk.keywords[j]))
                {
                  ret = GNUNET_YES;
                  break;
                }
            }
          if (ret == GNUNET_NO)
            return GNUNET_NO;
        }
      return GNUNET_YES;

    case GNUNET_FS_URI_LOC:
      if (memcmp(&u1->data.loc,
                 &u2->data.loc,
                 sizeof(struct FileIdentifier) +
                 sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey) +
                 sizeof(struct GNUNET_TIME_Absolute) +
                 sizeof(unsigned short) + sizeof(unsigned short)) != 0)
        return GNUNET_NO;
      return GNUNET_YES;

    default:
      return GNUNET_NO;
    }
}


int
GNUNET_FS_uri_test_sks(const struct GNUNET_FS_Uri *uri)
{
  return uri->type == GNUNET_FS_URI_SKS;
}


int
GNUNET_FS_uri_sks_get_namespace(const struct GNUNET_FS_Uri *uri,
                                struct GNUNET_CRYPTO_EcdsaPublicKey *pseudonym)
{
  if (!GNUNET_FS_uri_test_sks(uri))
    {
      GNUNET_break(0);
      return GNUNET_SYSERR;
    }
  *pseudonym = uri->data.sks.ns;
  return GNUNET_OK;
}


char *
GNUNET_FS_uri_sks_get_content_id(const struct GNUNET_FS_Uri *uri)
{
  if (!GNUNET_FS_uri_test_sks(uri))
    {
      GNUNET_break(0);
      return NULL;
    }
  return GNUNET_strdup(uri->data.sks.identifier);
}


int
GNUNET_FS_uri_test_ksk(const struct GNUNET_FS_Uri *uri)
{
#if EXTRA_CHECKS
  unsigned int i;

  if (uri->type == GNUNET_FS_URI_KSK)
    {
      for (i = 0; i < uri->data.ksk.keywordCount; i++)
        GNUNET_assert(uri->data.ksk.keywords[i] != NULL);
    }
#endif
  return uri->type == GNUNET_FS_URI_KSK;
}


int
GNUNET_FS_uri_test_chk(const struct GNUNET_FS_Uri *uri)
{
  return uri->type == GNUNET_FS_URI_CHK;
}


uint64_t
GNUNET_FS_uri_chk_get_file_size(const struct GNUNET_FS_Uri *uri)
{
  switch (uri->type)
    {
    case GNUNET_FS_URI_CHK:
      return GNUNET_ntohll(uri->data.chk.file_length);

    case GNUNET_FS_URI_LOC:
      return GNUNET_ntohll(uri->data.loc.fi.file_length);

    default:
      GNUNET_assert(0);
    }
  return 0; /* unreachable */
}


int
GNUNET_FS_uri_test_loc(const struct GNUNET_FS_Uri *uri)
{
  return uri->type == GNUNET_FS_URI_LOC;
}


static void
insert_non_mandatory_keyword(const char *s, char **array, int index)
{
  char *nkword;

  GNUNET_asprintf(&nkword,
                  " %s",  /* space to mark as 'non mandatory' */
                  s);
  array[index] = nkword;
}


static int
find_duplicate(const char *s, const char **array, int array_length)
{
  int j;

  for (j = array_length - 1; j >= 0; j--)
    if (0 == strcmp(&array[j][1], s))
      return GNUNET_YES;
  return GNUNET_NO;
}


static char *
normalize_metadata(enum EXTRACTOR_MetaFormat format,
                   const char *data,
                   size_t data_len)
{
  uint8_t *free_str = NULL;
  uint8_t *str_to_normalize = (uint8_t *)data;
  uint8_t *normalized;
  size_t r_len;

  if (str_to_normalize == NULL)
    return NULL;
  /* Don't trust libextractor */
  if (format == EXTRACTOR_METAFORMAT_UTF8)
    {
      free_str = (uint8_t *)u8_check((const uint8_t *)data, data_len);
      if (free_str == NULL)
        free_str = NULL;
      else
        format = EXTRACTOR_METAFORMAT_C_STRING;
    }
  if (format == EXTRACTOR_METAFORMAT_C_STRING)
    {
      free_str = u8_strconv_from_encoding(data,
                                          locale_charset(),
                                          iconveh_escape_sequence);
      if (free_str == NULL)
        return NULL;
    }

  normalized = u8_tolower(str_to_normalize,
                          strlen((char *)str_to_normalize),
                          NULL,
                          UNINORM_NFD,
                          NULL,
                          &r_len);
  /* free_str is allocated by libunistring internally, use free() */
  if (free_str != NULL)
    free(free_str);
  if (normalized != NULL)
    {
      /* u8_tolower allocates a non-NULL-terminated string! */
      free_str = GNUNET_malloc(r_len + 1);
      GNUNET_memcpy(free_str, normalized, r_len);
      free_str[r_len] = '\0';
      free(normalized);
      normalized = free_str;
    }
  return (char *)normalized;
}


static size_t
u8_strcount(const uint8_t *s)
{
  size_t count;
  ucs4_t c;

  GNUNET_assert(s != NULL);
  if (s[0] == 0)
    return 0;
  for (count = 0; s != NULL; count++)
    s = u8_next(&c, s);
  return count - 1;
}


static int
get_keywords_from_parens(const char *s, char **array, int index)
{
  int count = 0;
  char *open_paren;
  char *close_paren;
  char *ss;
  char tmp;

  if (NULL == s)
    return 0;
  ss = GNUNET_strdup(s);
  open_paren = ss - 1;
  while (NULL != (open_paren = strpbrk(open_paren + 1, "[{(")))
    {
      int match = 0;

      close_paren = strpbrk(open_paren + 1, "]})");
      if (NULL == close_paren)
        continue;
      switch (open_paren[0])
        {
        case '[':
          if (']' == close_paren[0])
            match = 1;
          break;

        case '{':
          if ('}' == close_paren[0])
            match = 1;
          break;

        case '(':
          if (')' == close_paren[0])
            match = 1;
          break;

        default:
          break;
        }
      if (match && (close_paren - open_paren > 1))
        {
          tmp = close_paren[0];
          close_paren[0] = '\0';
          /* Keywords must be at least 3 characters long */
          if (u8_strcount((const uint8_t *)&open_paren[1]) <= 2)
            {
              close_paren[0] = tmp;
              continue;
            }
          if (NULL != array)
            {
              char *normalized;
              if (GNUNET_NO == find_duplicate((const char *)&open_paren[1],
                                              (const char **)array,
                                              index + count))
                {
                  insert_non_mandatory_keyword((const char *)&open_paren[1],
                                               array,
                                               index + count);
                  count++;
                }
              normalized = normalize_metadata(EXTRACTOR_METAFORMAT_UTF8,
                                              &open_paren[1],
                                              close_paren - &open_paren[1]);
              if (normalized != NULL)
                {
                  if (GNUNET_NO == find_duplicate((const char *)normalized,
                                                  (const char **)array,
                                                  index + count))
                    {
                      insert_non_mandatory_keyword((const char *)normalized,
                                                   array,
                                                   index + count);
                      count++;
                    }
                  GNUNET_free(normalized);
                }
            }
          else
            count++;
          close_paren[0] = tmp;
        }
    }
  GNUNET_free(ss);
  return count;
}


#define TOKENS "_. /-!?#&+@\"\'\\;:,()[]{}$<>|"

static int
get_keywords_from_tokens(const char *s, char **array, int index)
{
  char *p;
  char *ss;
  int seps = 0;

  ss = GNUNET_strdup(s);
  for (p = strtok(ss, TOKENS); p != NULL; p = strtok(NULL, TOKENS))
    {
      /* Keywords must be at least 3 characters long */
      if (u8_strcount((const uint8_t *)p) <= 2)
        continue;
      if (NULL != array)
        {
          char *normalized;
          if (GNUNET_NO == find_duplicate(p, (const char **)array, index + seps))
            {
              insert_non_mandatory_keyword(p, array, index + seps);
              seps++;
            }
          normalized =
            normalize_metadata(EXTRACTOR_METAFORMAT_UTF8, p, strlen(p));
          if (normalized != NULL)
            {
              if (GNUNET_NO == find_duplicate((const char *)normalized,
                                              (const char **)array,
                                              index + seps))
                {
                  insert_non_mandatory_keyword((const char *)normalized,
                                               array,
                                               index + seps);
                  seps++;
                }
              GNUNET_free(normalized);
            }
        }
      else
        seps++;
    }
  GNUNET_free(ss);
  return seps;
}
#undef TOKENS


static int
gather_uri_data(void *cls,
                const char *plugin_name,
                enum EXTRACTOR_MetaType type,
                enum EXTRACTOR_MetaFormat format,
                const char *data_mime_type,
                const char *data,
                size_t data_len)
{
  struct GNUNET_FS_Uri *uri = cls;
  char *normalized_data;
  const char *sep;

  if ((format != EXTRACTOR_METAFORMAT_UTF8) &&
      (format != EXTRACTOR_METAFORMAT_C_STRING))
    return 0;
  /* Keywords must be at least 3 characters long
   * If given non-utf8 string it will, most likely, find it to be invalid,
   * and will return the length of its valid part, skipping the keyword.
   * If it does - fix the extractor, not this check!
   */
  if (u8_strcount((const uint8_t *)data) <= 2)
    return 0;
  if ((EXTRACTOR_METATYPE_MIMETYPE == type) &&
      (NULL != (sep = memchr(data, '/', data_len))) && (sep != data))
    {
      char *xtra;

      GNUNET_asprintf(&xtra, "mimetype:%.*s", (int)(sep - data), data);
      if (!find_duplicate(xtra,
                          (const char **)uri->data.ksk.keywords,
                          uri->data.ksk.keywordCount))
        {
          insert_non_mandatory_keyword(xtra,
                                       uri->data.ksk.keywords,
                                       uri->data.ksk.keywordCount);
          uri->data.ksk.keywordCount++;
        }
      GNUNET_free(xtra);
    }

  normalized_data = normalize_metadata(format, data, data_len);
  if (!find_duplicate(data,
                      (const char **)uri->data.ksk.keywords,
                      uri->data.ksk.keywordCount))
    {
      insert_non_mandatory_keyword(data,
                                   uri->data.ksk.keywords,
                                   uri->data.ksk.keywordCount);
      uri->data.ksk.keywordCount++;
    }
  if (NULL != normalized_data)
    {
      if (!find_duplicate(normalized_data,
                          (const char **)uri->data.ksk.keywords,
                          uri->data.ksk.keywordCount))
        {
          insert_non_mandatory_keyword(normalized_data,
                                       uri->data.ksk.keywords,
                                       uri->data.ksk.keywordCount);
          uri->data.ksk.keywordCount++;
        }
      GNUNET_free(normalized_data);
    }
  return 0;
}


struct GNUNET_FS_Uri *
GNUNET_FS_uri_ksk_create_from_meta_data(
  const struct GNUNET_CONTAINER_MetaData *md)
{
  struct GNUNET_FS_Uri *ret;
  char *filename;
  char *full_name = NULL;
  char *ss;
  int ent;
  int tok_keywords = 0;
  int paren_keywords = 0;

  if (NULL == md)
    return NULL;
  ret = GNUNET_new(struct GNUNET_FS_Uri);
  ret->type = GNUNET_FS_URI_KSK;
  ent = GNUNET_CONTAINER_meta_data_iterate(md, NULL, NULL);
  if (ent > 0)
    {
      full_name = GNUNET_CONTAINER_meta_data_get_first_by_types(
        md,
        EXTRACTOR_METATYPE_GNUNET_ORIGINAL_FILENAME,
        -1);
      if (NULL != full_name)
        {
          filename = full_name;
          while (NULL != (ss = strstr(filename, DIR_SEPARATOR_STR)))
            filename = ss + 1;
          tok_keywords = get_keywords_from_tokens(filename, NULL, 0);
          paren_keywords = get_keywords_from_parens(filename, NULL, 0);
        }
      /* x3 because there might be a normalized variant of every keyword,
         plus theoretically one more for mime... */
      ret->data.ksk.keywords =
        GNUNET_new_array((ent + tok_keywords + paren_keywords) * 3, char *);
      GNUNET_CONTAINER_meta_data_iterate(md, &gather_uri_data, ret);
    }
  if (tok_keywords > 0)
    ret->data.ksk.keywordCount +=
      get_keywords_from_tokens(filename,
                               ret->data.ksk.keywords,
                               ret->data.ksk.keywordCount);
  if (paren_keywords > 0)
    ret->data.ksk.keywordCount +=
      get_keywords_from_parens(filename,
                               ret->data.ksk.keywords,
                               ret->data.ksk.keywordCount);
  if (ent > 0)
    GNUNET_free_non_null(full_name);
  return ret;
}


static int
needs_percent(char c)
{
  return(!((isalnum((unsigned char)c)) || (c == '-') || (c == '_') ||
           (c == '.') || (c == '~')));
}


static char *
uri_ksk_to_string(const struct GNUNET_FS_Uri *uri)
{
  char **keywords;
  unsigned int keywordCount;
  size_t n;
  char *ret;
  unsigned int i;
  unsigned int j;
  unsigned int wpos;
  size_t slen;
  const char *keyword;

  if (uri->type != GNUNET_FS_URI_KSK)
    return NULL;
  keywords = uri->data.ksk.keywords;
  keywordCount = uri->data.ksk.keywordCount;
  n = keywordCount + strlen(GNUNET_FS_URI_PREFIX) +
      strlen(GNUNET_FS_URI_KSK_INFIX) + 1;
  for (i = 0; i < keywordCount; i++)
    {
      keyword = keywords[i];
      slen = strlen(keyword);
      n += slen;
      for (j = 0; j < slen; j++)
        {
          if ((j == 0) && (keyword[j] == ' '))
            {
              n--;
              continue; /* skip leading space */
            }
          if (needs_percent(keyword[j]))
            n += 2; /* will use %-encoding */
        }
    }
  ret = GNUNET_malloc(n);
  strcpy(ret, GNUNET_FS_URI_PREFIX);
  strcat(ret, GNUNET_FS_URI_KSK_INFIX);
  wpos = strlen(ret);
  for (i = 0; i < keywordCount; i++)
    {
      keyword = keywords[i];
      slen = strlen(keyword);
      for (j = 0; j < slen; j++)
        {
          if ((j == 0) && (keyword[j] == ' '))
            continue; /* skip leading space */
          if (needs_percent(keyword[j]))
            {
              sprintf(&ret[wpos], "%%%02X", (unsigned char)keyword[j]);
              wpos += 3;
            }
          else
            {
              ret[wpos++] = keyword[j];
            }
        }
      if (i != keywordCount - 1)
        ret[wpos++] = '+';
    }
  return ret;
}


static char *
uri_sks_to_string(const struct GNUNET_FS_Uri *uri)
{
  char *ret;
  char buf[1024];

  if (GNUNET_FS_URI_SKS != uri->type)
    return NULL;
  ret =
    GNUNET_STRINGS_data_to_string(&uri->data.sks.ns,
                                  sizeof(struct GNUNET_CRYPTO_EcdsaPublicKey),
                                  buf,
                                  sizeof(buf));
  GNUNET_assert(NULL != ret);
  ret[0] = '\0';
  GNUNET_asprintf(&ret,
                  "%s%s%s/%s",
                  GNUNET_FS_URI_PREFIX,
                  GNUNET_FS_URI_SKS_INFIX,
                  buf,
                  uri->data.sks.identifier);
  return ret;
}


static char *
uri_chk_to_string(const struct GNUNET_FS_Uri *uri)
{
  const struct FileIdentifier *fi;
  char *ret;
  struct GNUNET_CRYPTO_HashAsciiEncoded keyhash;
  struct GNUNET_CRYPTO_HashAsciiEncoded queryhash;

  if (uri->type != GNUNET_FS_URI_CHK)
    return NULL;
  fi = &uri->data.chk;
  GNUNET_CRYPTO_hash_to_enc(&fi->chk.key, &keyhash);
  GNUNET_CRYPTO_hash_to_enc(&fi->chk.query, &queryhash);

  GNUNET_asprintf(&ret,
                  "%s%s%s.%s.%llu",
                  GNUNET_FS_URI_PREFIX,
                  GNUNET_FS_URI_CHK_INFIX,
                  (const char *)&keyhash,
                  (const char *)&queryhash,
                  GNUNET_ntohll(fi->file_length));
  return ret;
}


static char *
uri_loc_to_string(const struct GNUNET_FS_Uri *uri)
{
  char *ret;
  struct GNUNET_CRYPTO_HashAsciiEncoded keyhash;
  struct GNUNET_CRYPTO_HashAsciiEncoded queryhash;
  char *peer_id;
  char peer_sig[SIGNATURE_ASCII_LENGTH + 1];

  GNUNET_CRYPTO_hash_to_enc(&uri->data.loc.fi.chk.key, &keyhash);
  GNUNET_CRYPTO_hash_to_enc(&uri->data.loc.fi.chk.query, &queryhash);
  peer_id =
    GNUNET_CRYPTO_eddsa_public_key_to_string(&uri->data.loc.peer.public_key);
  GNUNET_assert(
    NULL !=
    GNUNET_STRINGS_data_to_string(&uri->data.loc.contentSignature,
                                  sizeof(struct GNUNET_CRYPTO_EddsaSignature),
                                  peer_sig,
                                  sizeof(peer_sig)));
  GNUNET_asprintf(&ret,
                  "%s%s%s.%s.%llu.%s.%s.%llu",
                  GNUNET_FS_URI_PREFIX,
                  GNUNET_FS_URI_LOC_INFIX,
                  (const char *)&keyhash,
                  (const char *)&queryhash,
                  (unsigned long long)GNUNET_ntohll(
                    uri->data.loc.fi.file_length),
                  peer_id,
                  peer_sig,
                  (unsigned long long)
                  uri->data.loc.expirationTime.abs_value_us /
                  1000000LL);
  GNUNET_free(peer_id);
  return ret;
}


char *
GNUNET_FS_uri_to_string(const struct GNUNET_FS_Uri *uri)
{
  if (uri == NULL)
    {
      GNUNET_break(0);
      return NULL;
    }
  switch (uri->type)
    {
    case GNUNET_FS_URI_KSK:
      return uri_ksk_to_string(uri);

    case GNUNET_FS_URI_SKS:
      return uri_sks_to_string(uri);

    case GNUNET_FS_URI_CHK:
      return uri_chk_to_string(uri);

    case GNUNET_FS_URI_LOC:
      return uri_loc_to_string(uri);

    default:
      GNUNET_break(0);
      return NULL;
    }
}

/* end of fs_uri.c */