gnunet/src/fs/fs_api.c

/*
     This file is part of GNUnet.
     Copyright (C) 2001--2012 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
 */

/**
 * @file fs/fs_api.c
 * @brief main FS functions (master initialization, serialization, deserialization, shared code)
 * @author Christian Grothoff
 */

#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_fs_service.h"
#include "fs_api.h"
#include "fs_tree.h"

/**
 * How many block requests can we have outstanding in parallel at a time by default?
 */
#define DEFAULT_MAX_PARALLEL_REQUESTS (1024 * 10)

/**
 * How many downloads can we have outstanding in parallel at a time by default?
 */
#define DEFAULT_MAX_PARALLEL_DOWNLOADS 16

/**
 * Start the given job (send signal, remove from pending queue, update
 * counters and state).
 *
 * @param qe job to start
 */
static void
start_job (struct GNUNET_FS_QueueEntry *qe)
{
  qe->active = GNUNET_YES;
  qe->start (qe->cls);
  qe->start_times++;
  qe->h->active_blocks += qe->blocks;
  qe->h->active_downloads++;
  qe->start_time = GNUNET_TIME_absolute_get ();
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Starting job %p (%u active)\n",
              qe,
              qe->h->active_downloads);
  GNUNET_CONTAINER_DLL_remove (qe->h->pending_head, qe->h->pending_tail, qe);
  GNUNET_CONTAINER_DLL_insert_after (qe->h->running_head,
                                     qe->h->running_tail,
                                     qe->h->running_tail,
                                     qe);
}


/**
 * Stop the given job (send signal, remove from active queue, update
 * counters and state).
 *
 * @param qe job to stop
 */
static void
stop_job (struct GNUNET_FS_QueueEntry *qe)
{
  qe->active = GNUNET_NO;
  qe->stop (qe->cls);
  GNUNET_assert (0 < qe->h->active_downloads);
  qe->h->active_downloads--;
  qe->h->active_blocks -= qe->blocks;
  qe->run_time = GNUNET_TIME_relative_add (qe->run_time,
                                           GNUNET_TIME_absolute_get_duration (
                                             qe->start_time));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Stopping job %p (%u active)\n",
              qe,
              qe->h->active_downloads);
  GNUNET_CONTAINER_DLL_remove (qe->h->running_head, qe->h->running_tail, qe);
  GNUNET_CONTAINER_DLL_insert_after (qe->h->pending_head,
                                     qe->h->pending_tail,
                                     qe->h->pending_tail,
                                     qe);
}


/**
 * Process the jobs in the job queue, possibly starting some
 * and stopping others.
 *
 * @param cls the `struct GNUNET_FS_Handle *`
 */
static void
process_job_queue (void *cls)
{
  struct GNUNET_FS_Handle *h = cls;
  struct GNUNET_FS_QueueEntry *qe;
  struct GNUNET_FS_QueueEntry *next;
  struct GNUNET_TIME_Relative run_time;
  struct GNUNET_TIME_Relative restart_at;
  struct GNUNET_TIME_Relative rst;
  struct GNUNET_TIME_Absolute end_time;
  unsigned int num_downloads_waiting;
  unsigned int num_downloads_active;
  unsigned int num_downloads_expired;
  unsigned int num_probes_active;
  unsigned int num_probes_waiting;
  unsigned int num_probes_expired;
  int num_probes_change;
  int num_downloads_change;
  int block_limit_hit;

  h->queue_job = NULL;
  /* restart_at will be set to the time when it makes sense to
     re-evaluate the job queue (unless, of course, jobs complete
     or are added, then we'll be triggered immediately */
  restart_at = GNUNET_TIME_UNIT_FOREVER_REL;
  /* first, calculate some basic statistics on pending jobs */
  num_probes_waiting = 0;
  num_downloads_waiting = 0;
  for (qe = h->pending_head; NULL != qe; qe = qe->next)
  {
    switch (qe->priority)
    {
    case GNUNET_FS_QUEUE_PRIORITY_PROBE:
      num_probes_waiting++;
      break;

    case GNUNET_FS_QUEUE_PRIORITY_NORMAL:
      num_downloads_waiting++;
      break;

    default:
      GNUNET_break (0);
      break;
    }
  }
  /* now, calculate some basic statistics on running jobs */
  num_probes_active = 0;
  num_probes_expired = 0;
  num_downloads_active = 0;
  num_downloads_expired = 0;
  next = h->running_head;
  while (NULL != (qe = next))
  {
    next = qe->next;
    switch (qe->priority)
    {
    case GNUNET_FS_QUEUE_PRIORITY_PROBE:
      run_time = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 2);
      end_time = GNUNET_TIME_absolute_add (qe->start_time, run_time);
      rst = GNUNET_TIME_absolute_get_remaining (end_time);
      if (0 == rst.rel_value_us)
      {
        num_probes_expired++;
        stop_job (qe);
      }
      else
      {
        num_probes_active++;
        restart_at = GNUNET_TIME_relative_min (rst, restart_at);
      }
      break;

    case GNUNET_FS_QUEUE_PRIORITY_NORMAL:
      run_time =
        GNUNET_TIME_relative_saturating_multiply (h->avg_block_latency,
                                                  qe->blocks * qe->start_times);
      end_time = GNUNET_TIME_absolute_add (qe->start_time, run_time);
      rst = GNUNET_TIME_absolute_get_remaining (end_time);
      if (0 == rst.rel_value_us)
      {
        num_downloads_expired++;
        stop_job (qe);
      }
      else
      {
        num_downloads_active++;
        restart_at = GNUNET_TIME_relative_min (rst, restart_at);
      }
      break;

    default:
      GNUNET_break (0);
      break;
    }
  }
  GNUNET_break (h->active_downloads ==
                num_downloads_active + num_probes_active);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "PA: %u, PE: %u, PW: %u; DA: %u, DE: %u, DW: %u\n",
              num_probes_active,
              num_probes_expired,
              num_probes_waiting,
              num_downloads_active,
              num_downloads_expired,
              num_downloads_waiting);
  GNUNET_break (h->active_downloads + num_probes_active <=
                h->max_parallel_downloads);
  /* calculate start/stop decisions */
  if (h->active_downloads + num_downloads_waiting > h->max_parallel_downloads)
  {
    /* stop as many probes as there are downloads and probes */
    num_probes_change = -GNUNET_MIN (num_probes_active, num_downloads_waiting);
    /* start as many downloads as there are free slots, including those
       we just opened up */
    num_downloads_change =
      h->max_parallel_downloads - h->active_downloads - num_probes_change;
  }
  else
  {
    /* start all downloads (we can) */
    num_downloads_change = num_downloads_waiting;
    /* also start probes if there is room, but use a lower cap of (mpd/4) + 1 */
    if (1 + h->max_parallel_downloads / 4 >=
        (h->active_downloads + num_downloads_change))
      num_probes_change =
        GNUNET_MIN (num_probes_waiting,
                    (1 + h->max_parallel_downloads / 4)
                    - (h->active_downloads + num_downloads_change));
    else
      num_probes_change = 0;
  }
  GNUNET_break (num_downloads_change <= num_downloads_waiting);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Changing %d probes and %d/%u/%u downloads\n",
              num_probes_change,
              num_downloads_change,
              (unsigned int) h->active_downloads,
              (unsigned int) h->max_parallel_downloads);
  /* actually stop probes */
  next = h->running_head;
  while (NULL != (qe = next))
  {
    next = qe->next;
    if (GNUNET_FS_QUEUE_PRIORITY_PROBE != qe->priority)
      continue;
    if (num_probes_change < 0)
    {
      stop_job (qe);
      num_probes_change++;
      if (0 == num_probes_change)
        break;
    }
  }
  GNUNET_break (0 <= num_probes_change);

  /* start some more tasks if we now have empty slots */
  block_limit_hit = GNUNET_NO;
  next = h->pending_head;
  while ((NULL != (qe = next)) &&
         ((num_probes_change > 0) || (num_downloads_change > 0)))
  {
    next = qe->next;
    switch (qe->priority)
    {
    case GNUNET_FS_QUEUE_PRIORITY_PROBE:
      if (num_probes_change > 0)
      {
        start_job (qe);
        num_probes_change--;
        run_time = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 2);
        restart_at = GNUNET_TIME_relative_min (run_time, restart_at);
      }
      break;

    case GNUNET_FS_QUEUE_PRIORITY_NORMAL:
      if ((num_downloads_change > 0) &&
          ((qe->blocks + h->active_blocks <= h->max_parallel_requests) ||
           ((qe->blocks > h->max_parallel_requests) &&
            (0 == h->active_downloads))))
      {
        start_job (qe);
        num_downloads_change--;
      }
      else if (num_downloads_change > 0)
        block_limit_hit = GNUNET_YES;
      break;

    default:
      GNUNET_break (0);
      break;
    }
  }
  GNUNET_break ((0 == num_downloads_change) || (GNUNET_YES == block_limit_hit));
  GNUNET_break (0 == num_probes_change);

  GNUNET_log (
    GNUNET_ERROR_TYPE_DEBUG,
    "AD: %u, MP: %u; %d probes and %d downloads to start, will run again in %s\n",
    h->active_downloads,
    h->max_parallel_requests,
    num_probes_change,
    num_downloads_change,
    GNUNET_STRINGS_relative_time_to_string (restart_at, GNUNET_YES));

  /* make sure we run again, callbacks might have
     already re-scheduled the job, so cancel such
     an operation (if it exists) */
  if (NULL != h->queue_job)
    GNUNET_SCHEDULER_cancel (h->queue_job);
  h->queue_job =
    GNUNET_SCHEDULER_add_delayed (restart_at, &process_job_queue, h);
}


/**
 * Add a job to the queue.
 *
 * @param h handle to the overall FS state
 * @param start function to call to begin the job
 * @param stop function to call to pause the job, or on dequeue (if the job was running)
 * @param cls closure for start and stop
 * @param blocks number of blocks this jobs uses
 * @param priority how important is this download
 * @return queue handle
 */
struct GNUNET_FS_QueueEntry *
GNUNET_FS_queue_ (struct GNUNET_FS_Handle *h,
                  GNUNET_SCHEDULER_TaskCallback start,
                  GNUNET_SCHEDULER_TaskCallback stop,
                  void *cls,
                  unsigned int blocks,
                  enum GNUNET_FS_QueuePriority priority)
{
  struct GNUNET_FS_QueueEntry *qe;

  qe = GNUNET_new (struct GNUNET_FS_QueueEntry);
  qe->h = h;
  qe->start = start;
  qe->stop = stop;
  qe->cls = cls;
  qe->queue_time = GNUNET_TIME_absolute_get ();
  qe->blocks = blocks;
  qe->priority = priority;
  GNUNET_CONTAINER_DLL_insert_after (h->pending_head,
                                     h->pending_tail,
                                     h->pending_tail,
                                     qe);
  if (NULL != h->queue_job)
    GNUNET_SCHEDULER_cancel (h->queue_job);
  h->queue_job = GNUNET_SCHEDULER_add_now (&process_job_queue, h);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Queueing job %p\n", qe);
  return qe;
}


/**
 * Dequeue a job from the queue.
 *
 * @param qe handle for the job
 */
void
GNUNET_FS_dequeue_ (struct GNUNET_FS_QueueEntry *qe)
{
  struct GNUNET_FS_Handle *h;

  h = qe->h;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Dequeueing job %p\n", qe);
  if (GNUNET_YES == qe->active)
    stop_job (qe);
  GNUNET_CONTAINER_DLL_remove (h->pending_head, h->pending_tail, qe);
  GNUNET_free (qe);
  if (NULL != h->queue_job)
    GNUNET_SCHEDULER_cancel (h->queue_job);
  h->queue_job = GNUNET_SCHEDULER_add_now (&process_job_queue, h);
}


/**
 * Create a top-level activity entry.
 *
 * @param h global fs handle
 * @param ssf suspend signal function to use
 * @param ssf_cls closure for @a ssf
 * @return fresh top-level activity handle
 */
struct TopLevelActivity *
GNUNET_FS_make_top (struct GNUNET_FS_Handle *h,
                    SuspendSignalFunction ssf,
                    void *ssf_cls)
{
  struct TopLevelActivity *ret;

  ret = GNUNET_new (struct TopLevelActivity);
  ret->ssf = ssf;
  ret->ssf_cls = ssf_cls;
  GNUNET_CONTAINER_DLL_insert (h->top_head, h->top_tail, ret);
  return ret;
}


/**
 * Destroy a top-level activity entry.
 *
 * @param h global fs handle
 * @param top top level activity entry
 */
void
GNUNET_FS_end_top (struct GNUNET_FS_Handle *h, struct TopLevelActivity *top)
{
  GNUNET_CONTAINER_DLL_remove (h->top_head, h->top_tail, top);
  GNUNET_free (top);
}


/**
 * Closure for #GNUNET_FS_data_reader_file_().
 */
struct FileInfo
{
  /**
   * Name of the file to read.
   */
  char *filename;

  /**
   * File descriptor, NULL if it has not yet been opened.
   */
  struct GNUNET_DISK_FileHandle *fd;
};


/**
 * Function that provides data by reading from a file.
 *
 * @param cls closure with the `struct FileInfo *`
 * @param offset offset to read from; it is possible
 *            that the caller might need to go backwards
 *            a bit at times; set to `UINT64_MAX` to tell
 *            the reader that we won't be reading for a while
 *            (used to close the file descriptor but NOT fully
 *             clean up the reader's state); in this case,
 *            a value of '0' for @a max should be ignored
 * @param max maximum number of bytes that should be
 *            copied to @a buf; readers are not allowed
 *            to provide less data unless there is an error;
 *            a value of "0" will be used at the end to allow
 *            the reader to clean up its internal state
 * @param buf where the reader should write the data
 * @param emsg location for the reader to store an error message
 * @return number of bytes written, usually @a max, 0 on error
 */
size_t
GNUNET_FS_data_reader_file_ (void *cls,
                             uint64_t offset,
                             size_t max,
                             void *buf,
                             char **emsg)
{
  struct FileInfo *fi = cls;
  ssize_t ret;

  if (UINT64_MAX == offset)
  {
    if (NULL != fi->fd)
    {
      GNUNET_DISK_file_close (fi->fd);
      fi->fd = NULL;
    }
    return 0;
  }
  if (0 == max)
  {
    if (NULL != fi->fd)
      GNUNET_DISK_file_close (fi->fd);
    GNUNET_free (fi->filename);
    GNUNET_free (fi);
    return 0;
  }
  if (NULL == fi->fd)
  {
    fi->fd = GNUNET_DISK_file_open (fi->filename,
                                    GNUNET_DISK_OPEN_READ,
                                    GNUNET_DISK_PERM_NONE);
    if (NULL == fi->fd)
    {
      GNUNET_asprintf (emsg,
                       _ ("Could not open file `%s': %s"),
                       fi->filename,
                       strerror (errno));
      return 0;
    }
  }
  if ((GNUNET_SYSERR ==
       GNUNET_DISK_file_seek (fi->fd, offset, GNUNET_DISK_SEEK_SET)) ||
      (-1 == (ret = GNUNET_DISK_file_read (fi->fd, buf, max))))
  {
    GNUNET_asprintf (emsg,
                     _ ("Could not read file `%s': %s"),
                     fi->filename,
                     strerror (errno));
    return 0;
  }
  if (ret != max)
  {
    GNUNET_asprintf (emsg,
                     _ ("Short read reading from file `%s'!"),
                     fi->filename);
    return 0;
  }
  return max;
}


/**
 * Create the closure for the #GNUNET_FS_data_reader_file_() callback.
 *
 * @param filename file to read
 * @return closure to use, NULL on error
 */
void *
GNUNET_FS_make_file_reader_context_ (const char *filename)
{
  struct FileInfo *fi;

  fi = GNUNET_new (struct FileInfo);
  fi->filename = GNUNET_STRINGS_filename_expand (filename);
  if (NULL == fi->filename)
  {
    GNUNET_free (fi);
    return NULL;
  }
  return fi;
}


/**
 * Function that provides data by copying from a buffer.
 *
 * @param cls closure (points to the buffer)
 * @param offset offset to read from; it is possible
 *            that the caller might need to go backwards
 *            a bit at times; set to `UINT64_MAX` to tell
 *            the reader that we won't be reading for a while
 *            (used to close the file descriptor but NOT fully
 *             clean up the reader's state); in this case,
 *            a value of '0' for @a max should be ignored
 * @param max maximum number of bytes that should be
 *            copied to @a buf; readers are not allowed
 *            to provide less data unless there is an error;
 *            a value of "0" will be used at the end to allow
 *            the reader to clean up its internal state
 * @param buf where the reader should write the data
 * @param emsg location for the reader to store an error message
 * @return number of bytes written, usually @a max, 0 on error
 */
size_t
GNUNET_FS_data_reader_copy_ (void *cls,
                             uint64_t offset,
                             size_t max,
                             void *buf,
                             char **emsg)
{
  char *data = cls;

  if (UINT64_MAX == offset)
    return 0;
  if (0 == max)
  {
    GNUNET_free (data);
    return 0;
  }
  GNUNET_memcpy (buf, &data[offset], max);
  return max;
}


/**
 * Return the full filename where we would store state information
 * (for serialization/deserialization).
 *
 * @param h master context
 * @param ext component of the path
 * @param ent entity identifier (or emtpy string for the directory)
 * @return NULL on error
 */
static char *
get_serialization_file_name (struct GNUNET_FS_Handle *h,
                             const char *ext,
                             const char *ent)
{
  char *basename;
  char *ret;

  if (0 == (h->flags & GNUNET_FS_FLAGS_PERSISTENCE))
    return NULL; /* persistence not requested */
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename (h->cfg,
                                                            "fs",
                                                            "STATE_DIR",
                                                            &basename))
    return NULL;
  GNUNET_asprintf (&ret,
                   "%s%s%s%s%s%s%s",
                   basename,
                   DIR_SEPARATOR_STR,
                   h->client_name,
                   DIR_SEPARATOR_STR,
                   ext,
                   DIR_SEPARATOR_STR,
                   ent);
  GNUNET_free (basename);
  return ret;
}


/**
 * Return the full filename where we would store state information
 * (for serialization/deserialization) that is associated with a
 * parent operation.
 *
 * @param h master context
 * @param ext component of the path
 * @param uni name of the parent operation
 * @param ent entity identifier (or emtpy string for the directory)
 * @return NULL on error
 */
static char *
get_serialization_file_name_in_dir (struct GNUNET_FS_Handle *h,
                                    const char *ext,
                                    const char *uni,
                                    const char *ent)
{
  char *basename;
  char *ret;

  if (0 == (h->flags & GNUNET_FS_FLAGS_PERSISTENCE))
    return NULL; /* persistence not requested */
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename (h->cfg,
                                                            "fs",
                                                            "STATE_DIR",
                                                            &basename))
    return NULL;
  GNUNET_asprintf (&ret,
                   "%s%s%s%s%s%s%s.dir%s%s",
                   basename,
                   DIR_SEPARATOR_STR,
                   h->client_name,
                   DIR_SEPARATOR_STR,
                   ext,
                   DIR_SEPARATOR_STR,
                   uni,
                   DIR_SEPARATOR_STR,
                   ent);
  GNUNET_free (basename);
  return ret;
}


/**
 * Return a read handle for deserialization.
 *
 * @param h master context
 * @param ext component of the path
 * @param ent entity identifier (or emtpy string for the directory)
 * @return NULL on error
 */
static struct GNUNET_BIO_ReadHandle *
get_read_handle (struct GNUNET_FS_Handle *h, const char *ext, const char *ent)
{
  char *fn;
  struct GNUNET_BIO_ReadHandle *ret;

  fn = get_serialization_file_name (h, ext, ent);
  if (NULL == fn)
    return NULL;
  ret = GNUNET_BIO_read_open_file (fn);
  GNUNET_free (fn);
  return ret;
}


/**
 * Return a write handle for serialization.
 *
 * @param h master context
 * @param ext component of the path
 * @param ent entity identifier (or emtpy string for the directory)
 * @return NULL on error
 */
static struct GNUNET_BIO_WriteHandle *
get_write_handle (struct GNUNET_FS_Handle *h, const char *ext, const char *ent)
{
  char *fn;
  struct GNUNET_BIO_WriteHandle *ret;

  fn = get_serialization_file_name (h, ext, ent);
  if (NULL == fn)
    return NULL;
  ret = GNUNET_BIO_write_open_file (fn);
  GNUNET_break (NULL != ret);
  GNUNET_free (fn);
  return ret;
}


/**
 * Return a write handle for serialization.
 *
 * @param h master context
 * @param ext component of the path
 * @param uni name of parent
 * @param ent entity identifier (or emtpy string for the directory)
 * @return NULL on error
 */
static struct GNUNET_BIO_WriteHandle *
get_write_handle_in_dir (struct GNUNET_FS_Handle *h,
                         const char *ext,
                         const char *uni,
                         const char *ent)
{
  char *fn;
  struct GNUNET_BIO_WriteHandle *ret;

  fn = get_serialization_file_name_in_dir (h, ext, uni, ent);
  if (NULL == fn)
    return NULL;
  ret = GNUNET_BIO_write_open_file (fn);
  GNUNET_free (fn);
  return ret;
}


/**
 * Remove serialization/deserialization file from disk.
 *
 * @param h master context
 * @param ext component of the path
 * @param ent entity identifier
 */
void
GNUNET_FS_remove_sync_file_ (struct GNUNET_FS_Handle *h,
                             const char *ext,
                             const char *ent)
{
  char *filename;

  if ((NULL == ent) || (0 == strlen (ent)))
  {
    GNUNET_break (0);
    return;
  }
  filename = get_serialization_file_name (h, ext, ent);
  if (NULL != filename)
  {
    if ((0 != unlink (filename)) && (ENOENT != errno))
      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
    GNUNET_free (filename);
  }
}


/**
 * Remove serialization/deserialization file from disk.
 *
 * @param h master context
 * @param ext component of the path
 * @param uni parent name
 * @param ent entity identifier
 */
static void
remove_sync_file_in_dir (struct GNUNET_FS_Handle *h,
                         const char *ext,
                         const char *uni,
                         const char *ent)
{
  char *filename;

  if ((NULL == ent) || (0 == strlen (ent)))
  {
    GNUNET_break (0);
    return;
  }
  filename = get_serialization_file_name_in_dir (h, ext, uni, ent);
  if (NULL == filename)
    return;
  if (0 != unlink (filename))
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
  GNUNET_free (filename);
}


/**
 * Remove serialization/deserialization directory from disk.
 *
 * @param h master context
 * @param ext component of the path
 * @param uni unique name of parent
 */
void
GNUNET_FS_remove_sync_dir_ (struct GNUNET_FS_Handle *h,
                            const char *ext,
                            const char *uni)
{
  char *dn;

  if (NULL == uni)
    return;
  dn = get_serialization_file_name_in_dir (h, ext, uni, "");
  if (NULL == dn)
    return;
  if ((GNUNET_YES == GNUNET_DISK_directory_test (dn, GNUNET_YES)) &&
      (GNUNET_OK != GNUNET_DISK_directory_remove (dn)))
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "rmdir", dn);
  GNUNET_free (dn);
}


/**
 * Serialize a start-time.  Since we use start-times to
 * calculate the duration of some operation, we actually
 * do not serialize the absolute time but the (relative)
 * duration since the start time.  When we then
 * deserialize the start time, we take the current time and
 * subtract that duration so that we get again an absolute
 * time stamp that will result in correct performance
 * calculations.
 *
 * @param wh handle for writing
 * @param timestamp time to serialize
 * @return #GNUNET_OK on success
 */
static int
write_start_time (struct GNUNET_BIO_WriteHandle *wh,
                  struct GNUNET_TIME_Absolute timestamp)
{
  struct GNUNET_TIME_Relative dur;

  dur = GNUNET_TIME_absolute_get_duration (timestamp);
  return GNUNET_BIO_write_int64 (wh, "start time", dur.rel_value_us);
}


/**
 * Deserialize a start-time.  Since we use start-times to
 * calculate the duration of some operation, we actually
 * do not serialize the absolute time but the (relative)
 * duration since the start time.  Thus, when we then
 * deserialize the start time, we take the current time and
 * subtract that duration so that we get again an absolute
 * time stamp that will result in correct performance
 * calculations.
 *
 * @param rh handle for reading
 * @param timestamp where to write the deserialized timestamp
 * @return #GNUNET_OK on success
 */
static int
read_start_time (struct GNUNET_BIO_ReadHandle *rh,
                 struct GNUNET_TIME_Absolute *timestamp)
{
  struct GNUNET_TIME_Relative dur;

  if (GNUNET_OK != GNUNET_BIO_read_int64 (rh, "start time",
                                          (int64_t *) &dur.rel_value_us))
    return GNUNET_SYSERR;
  *timestamp = GNUNET_TIME_absolute_subtract (GNUNET_TIME_absolute_get (), dur);
  return GNUNET_OK;
}


/**
 * Using the given serialization filename, try to deserialize
 * the file-information tree associated with it.
 *
 * @param h master context
 * @param filename name of the file (without directory) with
 *        the infromation
 * @return NULL on error
 */
static struct GNUNET_FS_FileInformation *
deserialize_file_information (struct GNUNET_FS_Handle *h, const char *filename);


/**
 * Using the given serialization filename, try to deserialize
 * the file-information tree associated with it.
 *
 * @param h master context
 * @param fn name of the file (without directory) with
 *        the infromation
 * @param rh handle for reading
 * @return NULL on error
 */
static struct GNUNET_FS_FileInformation *
deserialize_fi_node (struct GNUNET_FS_Handle *h,
                     const char *fn,
                     struct GNUNET_BIO_ReadHandle *rh)
{
  struct GNUNET_FS_FileInformation *ret;
  struct GNUNET_FS_FileInformation *nxt;
  char b;
  char *ksks;
  char *chks;
  char *skss;
  char *filename;
  uint32_t dsize;

  if (GNUNET_OK != GNUNET_BIO_read (rh, "status flag", &b, sizeof(b)))
  {
    GNUNET_break (0);
    return NULL;
  }
  ret = GNUNET_new (struct GNUNET_FS_FileInformation);
  ret->h = h;
  ksks = NULL;
  chks = NULL;
  skss = NULL;
  filename = NULL;
  if ((GNUNET_OK != GNUNET_BIO_read_meta_data (rh, "metadata", &ret->meta)) ||
      (GNUNET_OK != GNUNET_BIO_read_string (rh, "ksk-uri", &ksks, 32 * 1024)) ||
      ((NULL != ksks) &&
       ((NULL == (ret->keywords = GNUNET_FS_uri_parse (ksks, NULL))) ||
        (GNUNET_YES != GNUNET_FS_uri_test_ksk (ret->keywords)))) ||
      (GNUNET_OK != GNUNET_BIO_read_string (rh, "chk-uri", &chks, 1024)) ||
      ((NULL != chks) &&
       ((NULL == (ret->chk_uri = GNUNET_FS_uri_parse (chks, NULL))) ||
        (GNUNET_YES != GNUNET_FS_uri_test_chk (ret->chk_uri)))) ||
      (GNUNET_OK != GNUNET_BIO_read_string (rh, "sks-uri", &skss, 1024)) ||
      ((NULL != skss) &&
       ((NULL == (ret->sks_uri = GNUNET_FS_uri_parse (skss, NULL))) ||
        (GNUNET_YES != GNUNET_FS_uri_test_sks (ret->sks_uri)))) ||
      (GNUNET_OK != read_start_time (rh, &ret->start_time)) ||
      (GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "emsg", &ret->emsg, 16 * 1024)) ||
      (GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "fn", &ret->filename, 16 * 1024)) ||
      (GNUNET_OK !=
       GNUNET_BIO_read_int64 (
         rh,
         "expiration time",
         (int64_t *) &ret->bo.expiration_time.abs_value_us)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (
         rh,
         "anonymity level",
         (int32_t *) &ret->bo.anonymity_level)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (
         rh,
         "content priority",
         (int32_t *) &ret->bo.content_priority)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (
         rh,
         "replication level",
         (int32_t *) &ret->bo.replication_level)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  switch (b)
  {
  case 0:   /* file-insert */
    if (GNUNET_OK != GNUNET_BIO_read_int64 (
          rh,
          "file size",
          (int64_t *) &ret->data.file.file_size))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    ret->is_directory = GNUNET_NO;
    ret->data.file.do_index = GNUNET_NO;
    ret->data.file.have_hash = GNUNET_NO;
    ret->data.file.index_start_confirmed = GNUNET_NO;
    if (GNUNET_NO == ret->is_published)
    {
      if (NULL == ret->filename)
      {
        ret->data.file.reader = &GNUNET_FS_data_reader_copy_;
        ret->data.file.reader_cls =
          GNUNET_malloc_large (ret->data.file.file_size);
        if (ret->data.file.reader_cls == NULL)
          goto cleanup;
        if (GNUNET_OK != GNUNET_BIO_read (rh,
                                          "file-data",
                                          ret->data.file.reader_cls,
                                          ret->data.file.file_size))
        {
          GNUNET_break (0);
          goto cleanup;
        }
      }
      else
      {
        ret->data.file.reader = &GNUNET_FS_data_reader_file_;
        ret->data.file.reader_cls =
          GNUNET_FS_make_file_reader_context_ (ret->filename);
      }
    }
    break;

  case 1:   /* file-index, no hash */
    if (NULL == ret->filename)
    {
      GNUNET_break (0);
      goto cleanup;
    }
    if (GNUNET_OK != GNUNET_BIO_read_int64 (
          rh,
          "file size",
          (int64_t *) &ret->data.file.file_size))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    ret->is_directory = GNUNET_NO;
    ret->data.file.do_index = GNUNET_YES;
    ret->data.file.have_hash = GNUNET_NO;
    ret->data.file.index_start_confirmed = GNUNET_NO;
    ret->data.file.reader = &GNUNET_FS_data_reader_file_;
    ret->data.file.reader_cls =
      GNUNET_FS_make_file_reader_context_ (ret->filename);
    break;

  case 2:   /* file-index-with-hash */
    if (NULL == ret->filename)
    {
      GNUNET_break (0);
      goto cleanup;
    }
    if ((GNUNET_OK != GNUNET_BIO_read_int64 (
           rh,
           "file size",
           (int64_t *) &ret->data.file.file_size)) ||
        (GNUNET_OK != GNUNET_BIO_read (rh,
                                       "fileid",
                                       &ret->data.file.file_id,
                                       sizeof(struct GNUNET_HashCode))))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    ret->is_directory = GNUNET_NO;
    ret->data.file.do_index = GNUNET_YES;
    ret->data.file.have_hash = GNUNET_YES;
    ret->data.file.index_start_confirmed = GNUNET_NO;
    ret->data.file.reader = &GNUNET_FS_data_reader_file_;
    ret->data.file.reader_cls =
      GNUNET_FS_make_file_reader_context_ (ret->filename);
    break;

  case 3:   /* file-index-with-hash-confirmed */
    if (NULL == ret->filename)
    {
      GNUNET_break (0);
      goto cleanup;
    }
    if ((GNUNET_OK != GNUNET_BIO_read_int64 (
           rh,
           "file size",
           (int64_t *) &ret->data.file.file_size)) ||
        (GNUNET_OK != GNUNET_BIO_read (rh,
                                       "fileid",
                                       &ret->data.file.file_id,
                                       sizeof(struct GNUNET_HashCode))))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    ret->is_directory = GNUNET_NO;
    ret->data.file.do_index = GNUNET_YES;
    ret->data.file.have_hash = GNUNET_YES;
    ret->data.file.index_start_confirmed = GNUNET_YES;
    ret->data.file.reader = &GNUNET_FS_data_reader_file_;
    ret->data.file.reader_cls =
      GNUNET_FS_make_file_reader_context_ (ret->filename);
    break;

  case 4:   /* directory */
    ret->is_directory = GNUNET_YES;
    if ((GNUNET_OK != GNUNET_BIO_read_int32 (rh, "dsize",
                                             (int32_t *) &dsize)) ||
        (GNUNET_OK !=
         GNUNET_BIO_read_int64 (
           rh,
           "contents completed",
           (int64_t *) &ret->data.dir.contents_completed)) ||
        (GNUNET_OK !=
         GNUNET_BIO_read_int64 (
           rh,
           "contents size",
           (int64_t *) &ret->data.dir.contents_size)) ||
        (NULL == (ret->data.dir.dir_data = GNUNET_malloc_large (dsize))) ||
        (GNUNET_OK !=
         GNUNET_BIO_read (rh, "dir-data", ret->data.dir.dir_data, dsize)) ||
        (GNUNET_OK !=
         GNUNET_BIO_read_string (rh, "ent-filename", &filename, 16 * 1024)))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    ret->data.dir.dir_size = (uint32_t) dsize;
    if (NULL != filename)
    {
      ret->data.dir.entries = deserialize_file_information (h, filename);
      GNUNET_free (filename);
      filename = NULL;
      nxt = ret->data.dir.entries;
      while (NULL != nxt)
      {
        nxt->dir = ret;
        nxt = nxt->next;
      }
    }
    break;

  default:
    GNUNET_break (0);
    goto cleanup;
  }
  ret->serialization = GNUNET_strdup (fn);
  if (GNUNET_OK !=
      GNUNET_BIO_read_string (rh, "nxt-filename", &filename, 16 * 1024))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (NULL != filename)
  {
    ret->next = deserialize_file_information (h, filename);
    GNUNET_free (filename);
    filename = NULL;
  }
  GNUNET_free (ksks);
  GNUNET_free (skss);
  GNUNET_free (chks);
  return ret;
cleanup:
  GNUNET_free (ksks);
  GNUNET_free (chks);
  GNUNET_free (skss);
  GNUNET_free (filename);
  GNUNET_FS_file_information_destroy (ret, NULL, NULL);
  return NULL;
}


/**
 * Using the given serialization filename, try to deserialize
 * the file-information tree associated with it.
 *
 * @param h master context
 * @param filename name of the file (without directory) with
 *        the infromation
 * @return NULL on error
 */
static struct GNUNET_FS_FileInformation *
deserialize_file_information (struct GNUNET_FS_Handle *h, const char *filename)
{
  struct GNUNET_FS_FileInformation *ret;
  struct GNUNET_BIO_ReadHandle *rh;
  char *emsg;
  char *fn;

  rh = get_read_handle (h, GNUNET_FS_SYNC_PATH_FILE_INFO, filename);
  if (NULL == rh)
    return NULL;
  ret = deserialize_fi_node (h, filename, rh);
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failed to resume publishing information `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  if (NULL == ret)
  {
    fn =
      get_serialization_file_name (h, GNUNET_FS_SYNC_PATH_FILE_INFO, filename);
    if (NULL != fn)
    {
      if (0 != unlink (fn))
        GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", fn);
      GNUNET_free (fn);
    }
  }
  return ret;
}


/**
 * Given a serialization name (full absolute path), return the
 * basename of the file (without the path), which must only
 * consist of the 6 random characters.
 *
 * @param fullname name to extract the basename from
 * @return copy of the basename, NULL on error
 */
static char *
get_serialization_short_name (const char *fullname)
{
  const char *end;
  const char *nxt;

  end = NULL;
  nxt = fullname;
  /* FIXME: we could do this faster since we know
   * the length of 'end'... */
  while ('\0' != *nxt)
  {
    if (DIR_SEPARATOR == *nxt)
      end = nxt + 1;
    nxt++;
  }
  if ((NULL == end) || (0 == strlen (end)))
  {
    GNUNET_break (0);
    return NULL;
  }
  GNUNET_break (6 == strlen (end));
  return GNUNET_strdup (end);
}


/**
 * Create a new random name for serialization.  Also checks if persistence
 * is enabled and returns NULL if not.
 *
 * @param h master context
 * @param ext component of the path
 * @return NULL on errror
 */
static char *
make_serialization_file_name (struct GNUNET_FS_Handle *h, const char *ext)
{
  char *fn;
  char *dn;
  char *ret;

  if (0 == (h->flags & GNUNET_FS_FLAGS_PERSISTENCE))
    return NULL; /* persistence not requested */
  dn = get_serialization_file_name (h, ext, "");
  if (NULL == dn)
    return NULL;
  if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (dn))
  {
    GNUNET_free (dn);
    return NULL;
  }
  fn = GNUNET_DISK_mktemp (dn);
  GNUNET_free (dn);
  if (NULL == fn)
    return NULL; /* epic fail */
  ret = get_serialization_short_name (fn);
  GNUNET_free (fn);
  return ret;
}


/**
 * Create a new random name for serialization.  Also checks if persistence
 * is enabled and returns NULL if not.
 *
 * @param h master context
 * @param ext component of the path
 * @param uni name of parent
 * @return NULL on errror
 */
static char *
make_serialization_file_name_in_dir (struct GNUNET_FS_Handle *h,
                                     const char *ext,
                                     const char *uni)
{
  char *fn;
  char *dn;
  char *ret;

  if (0 == (h->flags & GNUNET_FS_FLAGS_PERSISTENCE))
    return NULL; /* persistence not requested */
  dn = get_serialization_file_name_in_dir (h, ext, uni, "");
  if (NULL == dn)
    return NULL;
  if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (dn))
  {
    GNUNET_free (dn);
    return NULL;
  }
  fn = GNUNET_DISK_mktemp (dn);
  GNUNET_free (dn);
  if (NULL == fn)
    return NULL; /* epic fail */
  ret = get_serialization_short_name (fn);
  GNUNET_free (fn);
  return ret;
}


/**
 * Copy all of the data from the reader to the write handle.
 *
 * @param wh write handle
 * @param fi file with reader
 * @return #GNUNET_OK on success
 */
static int
copy_from_reader (struct GNUNET_BIO_WriteHandle *wh,
                  struct GNUNET_FS_FileInformation *fi)
{
  char buf[32 * 1024];
  uint64_t off;
  size_t ret;
  size_t left;
  char *emsg;

  emsg = NULL;
  off = 0;
  while (off < fi->data.file.file_size)
  {
    left = GNUNET_MIN (sizeof(buf), fi->data.file.file_size - off);
    ret =
      fi->data.file.reader (fi->data.file.reader_cls, off, left, buf, &emsg);
    if (0 == ret)
    {
      GNUNET_free (emsg);
      return GNUNET_SYSERR;
    }
    if (GNUNET_OK != GNUNET_BIO_write (wh, "copied from reader", buf, ret))
      return GNUNET_SYSERR;
    off += ret;
  }
  return GNUNET_OK;
}


/**
 * Create a temporary file on disk to store the current
 * state of @a fi in.
 *
 * @param fi file information to sync with disk
 */
void
GNUNET_FS_file_information_sync_ (struct GNUNET_FS_FileInformation *fi)
{
  char *fn;
  struct GNUNET_BIO_WriteHandle *wh;
  char b;
  char *ksks;
  char *chks;
  char *skss;

  if (NULL == fi->serialization)
    fi->serialization =
      make_serialization_file_name (fi->h, GNUNET_FS_SYNC_PATH_FILE_INFO);
  if (NULL == fi->serialization)
    return;
  wh =
    get_write_handle (fi->h, GNUNET_FS_SYNC_PATH_FILE_INFO, fi->serialization);
  if (NULL == wh)
  {
    GNUNET_free (fi->serialization);
    fi->serialization = NULL;
    return;
  }
  if (GNUNET_YES == fi->is_directory)
    b = 4;
  else if (GNUNET_YES == fi->data.file.index_start_confirmed)
    b = 3;
  else if (GNUNET_YES == fi->data.file.have_hash)
    b = 2;
  else if (GNUNET_YES == fi->data.file.do_index)
    b = 1;
  else
    b = 0;
  if (NULL != fi->keywords)
    ksks = GNUNET_FS_uri_to_string (fi->keywords);
  else
    ksks = NULL;
  if (NULL != fi->chk_uri)
    chks = GNUNET_FS_uri_to_string (fi->chk_uri);
  else
    chks = NULL;
  if (NULL != fi->sks_uri)
    skss = GNUNET_FS_uri_to_string (fi->sks_uri);
  else
    skss = NULL;
  struct GNUNET_BIO_WriteSpec ws1[] = {
    GNUNET_BIO_write_spec_object ("b", &b, sizeof (b)),
    GNUNET_BIO_write_spec_meta_data ("meta", fi->meta),
    GNUNET_BIO_write_spec_string ("ksks", ksks),
    GNUNET_BIO_write_spec_string ("chks", chks),
    GNUNET_BIO_write_spec_string ("skss", skss),
    GNUNET_BIO_write_spec_end (),
  };
  struct GNUNET_BIO_WriteSpec ws2[] = {
    GNUNET_BIO_write_spec_string ("emsg", fi->emsg),
    GNUNET_BIO_write_spec_string ("filename", fi->filename),
    GNUNET_BIO_write_spec_int64 (
      "expiration time",
      (int64_t *) &fi->bo.expiration_time.abs_value_us),
    GNUNET_BIO_write_spec_int32 (
      "anonymity level",
      (int32_t *) &fi->bo.anonymity_level),
    GNUNET_BIO_write_spec_int32 (
      "content priority",
      (int32_t *) &fi->bo.content_priority),
    GNUNET_BIO_write_spec_int32 (
      "replication level",
      (int32_t *) &fi->bo.replication_level),
    GNUNET_BIO_write_spec_end (),
  };
  if ((GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws1)) ||
      (GNUNET_OK != write_start_time (wh, fi->start_time)) ||
      (GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws2)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  GNUNET_free (chks);
  chks = NULL;
  GNUNET_free (ksks);
  ksks = NULL;
  GNUNET_free (skss);
  skss = NULL;

  switch (b)
  {
  case 0:   /* file-insert */
    if (GNUNET_OK != GNUNET_BIO_write_int64 (wh, "file size",
                                             fi->data.file.file_size))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    if ((GNUNET_NO == fi->is_published) && (NULL == fi->filename))
      if (GNUNET_OK != copy_from_reader (wh, fi))
      {
        GNUNET_break (0);
        goto cleanup;
      }
    break;

  case 1:   /* file-index, no hash */
    if (NULL == fi->filename)
    {
      GNUNET_break (0);
      goto cleanup;
    }
    if (GNUNET_OK != GNUNET_BIO_write_int64 (wh, "file size",
                                             fi->data.file.file_size))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    break;

  case 2:   /* file-index-with-hash */
  case 3:   /* file-index-with-hash-confirmed */
    if (NULL == fi->filename)
    {
      GNUNET_break (0);
      goto cleanup;
    }
    if ((GNUNET_OK != GNUNET_BIO_write_int64 (wh, "file size",
                                              fi->data.file.file_size)) ||
        (GNUNET_OK != GNUNET_BIO_write (wh,
                                        "file id",
                                        &fi->data.file.file_id,
                                        sizeof(struct GNUNET_HashCode))))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    break;

  case 4:   /* directory */
    if ((NULL != fi->data.dir.entries) &&
        (NULL == fi->data.dir.entries->serialization))
      GNUNET_FS_file_information_sync_ (fi->data.dir.entries);
    struct GNUNET_BIO_WriteSpec ws[] = {
      GNUNET_BIO_write_spec_int32 ("dir size",
                                   (int32_t *) &fi->data.dir.dir_size),
      GNUNET_BIO_write_spec_int64 (
        "contents completed",
        (int64_t *) &fi->data.dir.contents_completed),
      GNUNET_BIO_write_spec_int64 ("contents size",
                                   (int64_t *) &fi->data.dir.contents_size),
      GNUNET_BIO_write_spec_object ("dir data",
                                    fi->data.dir.dir_data,
                                    (uint32_t) fi->data.dir.dir_size),
      GNUNET_BIO_write_spec_string ("dir entries",
                                    (fi->data.dir.entries == NULL)
                                    ? NULL
                                    : fi->data.dir.entries->serialization),
      GNUNET_BIO_write_spec_end (),
    };
    if ((GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws)))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    break;

  default:
    GNUNET_assert (0);
    goto cleanup;
  }
  if ((NULL != fi->next) && (NULL == fi->next->serialization))
    GNUNET_FS_file_information_sync_ (fi->next);
  if (GNUNET_OK != GNUNET_BIO_write_string (wh,
                                            "serialization",
                                            (fi->next != NULL)
                                            ? fi->next->serialization
                                            : NULL))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (GNUNET_OK != GNUNET_BIO_write_close (wh, NULL))
  {
    wh = NULL;
    GNUNET_break (0);
    goto cleanup;
  }
  return; /* done! */
cleanup:
  if (NULL != wh)
    (void) GNUNET_BIO_write_close (wh, NULL);
  GNUNET_free (chks);
  GNUNET_free (ksks);
  GNUNET_free (skss);
  fn = get_serialization_file_name (fi->h,
                                    GNUNET_FS_SYNC_PATH_FILE_INFO,
                                    fi->serialization);
  if (NULL != fn)
  {
    if (0 != unlink (fn))
      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", fn);
    GNUNET_free (fn);
  }
  GNUNET_free (fi->serialization);
  fi->serialization = NULL;
}


/**
 * Find the entry in the file information struct where the
 * serialization filename matches the given name.
 *
 * @param pos file information to search
 * @param srch filename to search for
 * @return NULL if srch was not found in this subtree
 */
static struct GNUNET_FS_FileInformation *
find_file_position (struct GNUNET_FS_FileInformation *pos, const char *srch)
{
  struct GNUNET_FS_FileInformation *r;

  while (NULL != pos)
  {
    if (0 == strcmp (srch, pos->serialization))
      return pos;
    if ((GNUNET_YES == pos->is_directory) &&
        (NULL != (r = find_file_position (pos->data.dir.entries, srch))))
      return r;
    pos = pos->next;
  }
  return NULL;
}


/**
 * Signal the FS's progress function that we are resuming
 * an upload.
 *
 * @param cls closure (of type `struct GNUNET_FS_PublishContext *`, for the parent (!))
 * @param fi the entry in the publish-structure
 * @param length length of the file or directory
 * @param meta metadata for the file or directory (can be modified)
 * @param uri pointer to the keywords that will be used for this entry (can be modified)
 * @param bo block options (can be modified)
 * @param do_index should we index?
 * @param client_info pointer to client context set upon creation (can be modified)
 * @return #GNUNET_OK to continue (always)
 */
static int
fip_signal_resume (void *cls,
                   struct GNUNET_FS_FileInformation *fi,
                   uint64_t length,
                   struct GNUNET_CONTAINER_MetaData *meta,
                   struct GNUNET_FS_Uri **uri,
                   struct GNUNET_FS_BlockOptions *bo,
                   int *do_index,
                   void **client_info)
{
  struct GNUNET_FS_PublishContext *pc = cls;
  struct GNUNET_FS_ProgressInfo pi;

  if (GNUNET_YES == pc->skip_next_fi_callback)
  {
    pc->skip_next_fi_callback = GNUNET_NO;
    return GNUNET_OK;
  }
  pi.status = GNUNET_FS_STATUS_PUBLISH_RESUME;
  pi.value.publish.specifics.resume.message = fi->emsg;
  pi.value.publish.specifics.resume.chk_uri = fi->chk_uri;
  *client_info = GNUNET_FS_publish_make_status_ (&pi, pc, fi, 0);
  if (GNUNET_YES == GNUNET_FS_meta_data_test_for_directory (meta))
  {
    /* process entries in directory */
    pc->skip_next_fi_callback = GNUNET_YES;
    GNUNET_FS_file_information_inspect (fi, &fip_signal_resume, pc);
  }
  return GNUNET_OK;
}


/**
 * Function called with a filename of serialized publishing operation
 * to deserialize.
 *
 * @param cls the `struct GNUNET_FS_Handle *`
 * @param filename complete filename (absolute path)
 * @return #GNUNET_OK (continue to iterate)
 */
static int
deserialize_publish_file (void *cls, const char *filename)
{
  struct GNUNET_FS_Handle *h = cls;
  struct GNUNET_BIO_ReadHandle *rh;
  struct GNUNET_FS_PublishContext *pc;
  int32_t options;
  int32_t all_done;
  int32_t have_ns;
  char *fi_root;
  struct GNUNET_CRYPTO_EcdsaPrivateKey ns;
  char *fi_pos;
  char *emsg;

  pc = GNUNET_new (struct GNUNET_FS_PublishContext);
  pc->h = h;
  pc->serialization = get_serialization_short_name (filename);
  fi_root = NULL;
  fi_pos = NULL;
  rh = GNUNET_BIO_read_open_file (filename);
  if (NULL == rh)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  struct GNUNET_BIO_ReadSpec rs[] = {
    GNUNET_BIO_read_spec_string ("publish-nid", &pc->nid, 1024),
    GNUNET_BIO_read_spec_string ("publish-nuid", &pc->nuid, 1024),
    GNUNET_BIO_read_spec_int32 ("options", &options),
    GNUNET_BIO_read_spec_int32 ("all done", &all_done),
    GNUNET_BIO_read_spec_int32 ("have ns", &have_ns),
    GNUNET_BIO_read_spec_string ("publish-firoot", &fi_root, 128),
    GNUNET_BIO_read_spec_string ("publish-fipos", &fi_pos, 128),
    GNUNET_BIO_read_spec_end (),
  };
  if ((GNUNET_OK != GNUNET_BIO_read_spec_commit (rh, rs)) ||
      ((GNUNET_YES == have_ns) &&
       (GNUNET_OK != GNUNET_BIO_read (rh, "publish-ns", &ns, sizeof(ns)))))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  pc->options = options;
  pc->all_done = all_done;
  if (NULL == fi_root)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  pc->fi = deserialize_file_information (h, fi_root);
  if (NULL == pc->fi)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (GNUNET_YES == have_ns)
  {
    pc->ns = GNUNET_new (struct GNUNET_CRYPTO_EcdsaPrivateKey);
    *pc->ns = ns;
  }
  if ((0 == (pc->options & GNUNET_FS_PUBLISH_OPTION_SIMULATE_ONLY)) &&
      (GNUNET_YES != pc->all_done))
  {
    pc->dsh = GNUNET_DATASTORE_connect (h->cfg);
    if (NULL == pc->dsh)
      goto cleanup;
  }
  if (NULL != fi_pos)
  {
    pc->fi_pos = find_file_position (pc->fi, fi_pos);
    GNUNET_free (fi_pos);
    fi_pos = NULL;
    if (NULL == pc->fi_pos)
    {
      /* failed to find position for resuming, outch! Will start from root! */
      GNUNET_break (0);
      if (GNUNET_YES != pc->all_done)
        pc->fi_pos = pc->fi;
    }
  }
  GNUNET_free (fi_root);
  fi_root = NULL;
  /* generate RESUME event(s) */
  GNUNET_FS_file_information_inspect (pc->fi, &fip_signal_resume, pc);

  /* re-start publishing (if needed)... */
  if (GNUNET_YES != pc->all_done)
  {
    GNUNET_assert (NULL == pc->upload_task);
    pc->upload_task =
      GNUNET_SCHEDULER_add_with_priority (GNUNET_SCHEDULER_PRIORITY_BACKGROUND,
                                          &GNUNET_FS_publish_main_,
                                          pc);
  }
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failure while resuming publishing operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  pc->top = GNUNET_FS_make_top (h, &GNUNET_FS_publish_signal_suspend_, pc);
  return GNUNET_OK;
cleanup:
  GNUNET_free (pc->nid);
  GNUNET_free (pc->nuid);
  GNUNET_free (fi_root);
  GNUNET_free (fi_pos);
  if ((NULL != rh) && (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg)))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failed to resume publishing operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  if (NULL != pc->fi)
    GNUNET_FS_file_information_destroy (pc->fi, NULL, NULL);
  if (0 != unlink (filename))
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
  GNUNET_free (pc->serialization);
  GNUNET_free (pc);
  return GNUNET_OK;
}


/**
 * Synchronize this publishing struct with its mirror
 * on disk.  Note that all internal FS-operations that change
 * publishing structs should already call "sync" internally,
 * so this function is likely not useful for clients.
 *
 * @param pc the struct to sync
 */
void
GNUNET_FS_publish_sync_ (struct GNUNET_FS_PublishContext *pc)
{
  struct GNUNET_BIO_WriteHandle *wh;
  int32_t have_ns;

  if (NULL == pc->serialization)
    pc->serialization =
      make_serialization_file_name (pc->h, GNUNET_FS_SYNC_PATH_MASTER_PUBLISH);
  if (NULL == pc->serialization)
    return;
  if (NULL == pc->fi)
    return;
  if (NULL == pc->fi->serialization)
  {
    GNUNET_break (0);
    return;
  }
  wh = get_write_handle (pc->h,
                         GNUNET_FS_SYNC_PATH_MASTER_PUBLISH,
                         pc->serialization);
  if (NULL == wh)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  have_ns = (NULL != pc->ns) ? GNUNET_YES : GNUNET_NO;
  struct GNUNET_BIO_WriteSpec ws[] = {
    GNUNET_BIO_write_spec_string ("nid", pc->nid),
    GNUNET_BIO_write_spec_string ("nuid", pc->nuid),
    GNUNET_BIO_write_spec_int32 ("options", (int32_t *) &pc->options),
    GNUNET_BIO_write_spec_int32 ("all done", &pc->all_done),
    GNUNET_BIO_write_spec_int32 ("have ns", &have_ns),
    GNUNET_BIO_write_spec_string ("serialization", pc->fi->serialization),
    GNUNET_BIO_write_spec_string ("pos serialization", (NULL == pc->fi_pos)
                                  ? NULL
                                  : pc->fi_pos->serialization),
    GNUNET_BIO_read_spec_end ()
  };
  if ((GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws)) ||
      ((NULL != pc->ns) &&
       (GNUNET_OK !=
        GNUNET_BIO_write (wh,
                          "ns",
                          pc->ns,
                          sizeof(struct GNUNET_CRYPTO_EcdsaPrivateKey)))))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (GNUNET_OK != GNUNET_BIO_write_close (wh, NULL))
  {
    wh = NULL;
    GNUNET_break (0);
    goto cleanup;
  }
  return;
cleanup:
  if (NULL != wh)
    (void) GNUNET_BIO_write_close (wh, NULL);
  GNUNET_FS_remove_sync_file_ (pc->h,
                               GNUNET_FS_SYNC_PATH_MASTER_PUBLISH,
                               pc->serialization);
  GNUNET_free (pc->serialization);
  pc->serialization = NULL;
}


/**
 * Synchronize this unindex struct with its mirror
 * on disk.  Note that all internal FS-operations that change
 * publishing structs should already call "sync" internally,
 * so this function is likely not useful for clients.
 *
 * @param uc the struct to sync
 */
void
GNUNET_FS_unindex_sync_ (struct GNUNET_FS_UnindexContext *uc)
{
  struct GNUNET_BIO_WriteHandle *wh;
  char *uris;

  if (NULL == uc->serialization)
    uc->serialization =
      make_serialization_file_name (uc->h, GNUNET_FS_SYNC_PATH_MASTER_UNINDEX);
  if (NULL == uc->serialization)
    return;
  wh = get_write_handle (uc->h,
                         GNUNET_FS_SYNC_PATH_MASTER_UNINDEX,
                         uc->serialization);
  if (NULL == wh)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (NULL != uc->ksk_uri)
    uris = GNUNET_FS_uri_to_string (uc->ksk_uri);
  else
    uris = NULL;
  struct GNUNET_BIO_WriteSpec ws1[] = {
    GNUNET_BIO_write_spec_string ("filename", uc->filename),
    GNUNET_BIO_write_spec_int64 ("file size", (int64_t *) &uc->file_size),
    GNUNET_BIO_write_spec_end (),
  };
  struct GNUNET_BIO_WriteSpec ws2[] = {
    GNUNET_BIO_write_spec_int32 ("state", (int32_t *) &uc->state),
    GNUNET_BIO_write_spec_object ("hashkey", &uc->chk,
                                  sizeof (struct ContentHashKey)),
    GNUNET_BIO_write_spec_string ("uris", uris),
    GNUNET_BIO_write_spec_int32 ("ksk offset", (int32_t *) &uc->ksk_offset),
    GNUNET_BIO_write_spec_end (),
  };
  if ((GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws1)) ||
      (GNUNET_OK != write_start_time (wh, uc->start_time)) ||
      (GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws2)) ||
      ((uc->state == UNINDEX_STATE_FS_NOTIFY) &&
       (GNUNET_OK != GNUNET_BIO_write (wh,
                                       "file id",
                                       &uc->file_id,
                                       sizeof(struct GNUNET_HashCode)))) ||
      ((uc->state == UNINDEX_STATE_ERROR) &&
       (GNUNET_OK != GNUNET_BIO_write_string (wh, "emsg", uc->emsg))))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (GNUNET_OK != GNUNET_BIO_write_close (wh, NULL))
  {
    wh = NULL;
    GNUNET_break (0);
    goto cleanup;
  }
  return;
cleanup:
  if (NULL != wh)
    (void) GNUNET_BIO_write_close (wh, NULL);
  GNUNET_FS_remove_sync_file_ (uc->h,
                               GNUNET_FS_SYNC_PATH_MASTER_UNINDEX,
                               uc->serialization);
  GNUNET_free (uc->serialization);
  uc->serialization = NULL;
}


/**
 * Serialize a download request.
 *
 * @param wh handle for writing the download request to disk
 * @param dr the the request to write to disk
 * @return #GNUNET_YES on success, #GNUNET_NO on error
 */
static int
write_download_request (struct GNUNET_BIO_WriteHandle *wh,
                        struct DownloadRequest *dr)
{
  unsigned int i;
  struct GNUNET_BIO_WriteSpec ws[] = {
    GNUNET_BIO_write_spec_int32 ("state", (int32_t *) &dr->state),
    GNUNET_BIO_write_spec_int64 ("offset", (int64_t *) &dr->offset),
    GNUNET_BIO_write_spec_int32 ("num children", (int32_t *) &dr->num_children),
    GNUNET_BIO_write_spec_int32 ("depth", (int32_t *) &dr->depth),
    GNUNET_BIO_write_spec_end (),
  };

  if ((GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws)))
    return GNUNET_NO;
  if ((BRS_CHK_SET == dr->state) &&
      (GNUNET_OK !=
       GNUNET_BIO_write (wh, "hashkey",
                         &dr->chk, sizeof(struct ContentHashKey))))
    return GNUNET_NO;
  for (i = 0; i < dr->num_children; i++)
    if (GNUNET_NO == write_download_request (wh, dr->children[i]))
      return GNUNET_NO;
  return GNUNET_YES;
}


/**
 * Read a download request tree.
 *
 * @param rh cadet to read from
 * @return value the download request read from disk, NULL on error
 */
static struct DownloadRequest *
read_download_request (struct GNUNET_BIO_ReadHandle *rh)
{
  struct DownloadRequest *dr;
  unsigned int i;

  dr = GNUNET_new (struct DownloadRequest);
  struct GNUNET_BIO_ReadSpec rs[] = {
    GNUNET_BIO_read_spec_int32 ("state", (int32_t *) &dr->state),
    GNUNET_BIO_read_spec_int64 ("offset", (int64_t *) &dr->offset),
    GNUNET_BIO_read_spec_int32 ("num children", (int32_t *) &dr->num_children),
    GNUNET_BIO_read_spec_end (),
  };
  if ((GNUNET_OK != GNUNET_BIO_read_spec_commit (rh, rs)) ||
      (dr->num_children > CHK_PER_INODE) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "depth",
                                           (int32_t *) &dr->depth)) ||
      ((0 == dr->depth) && (dr->num_children > 0)) ||
      ((dr->depth > 0) && (0 == dr->num_children)))
  {
    GNUNET_break (0);
    dr->num_children = 0;
    goto cleanup;
  }
  if (dr->num_children > 0)
    dr->children =
      GNUNET_malloc (dr->num_children * sizeof(struct DownloadRequest *));
  switch (dr->state)
  {
  case BRS_INIT:
  case BRS_RECONSTRUCT_DOWN:
  case BRS_RECONSTRUCT_META_UP:
  case BRS_RECONSTRUCT_UP:
    break;

  case BRS_CHK_SET:
    if (GNUNET_OK !=
        GNUNET_BIO_read (rh, "chk", &dr->chk, sizeof(struct ContentHashKey)))
      goto cleanup;
    break;

  case BRS_DOWNLOAD_DOWN:
  case BRS_DOWNLOAD_UP:
  case BRS_ERROR:
    break;

  default:
    GNUNET_break (0);
    goto cleanup;
  }
  for (i = 0; i < dr->num_children; i++)
  {
    if (NULL == (dr->children[i] = read_download_request (rh)))
      goto cleanup;
    dr->children[i]->parent = dr;
  }
  return dr;
cleanup:
  GNUNET_FS_free_download_request_ (dr);
  return NULL;
}


/**
 * Compute the name of the sync file (or directory) for the given download
 * context.
 *
 * @param dc download context to compute for
 * @param uni unique filename to use, use "" for the directory name
 * @param ext extension to use, use ".dir" for our own subdirectory
 * @return the expanded file name, NULL for none
 */
static char *
get_download_sync_filename (struct GNUNET_FS_DownloadContext *dc,
                            const char *uni,
                            const char *ext)
{
  char *par;
  char *epar;

  if (dc->parent == NULL)
    return get_serialization_file_name (dc->h,
                                        (dc->search != NULL)
                                        ? GNUNET_FS_SYNC_PATH_CHILD_DOWNLOAD
                                        : GNUNET_FS_SYNC_PATH_MASTER_DOWNLOAD,
                                        uni);
  if (NULL == dc->parent->serialization)
    return NULL;
  par = get_download_sync_filename (dc->parent, dc->parent->serialization, "");
  if (NULL == par)
    return NULL;
  GNUNET_asprintf (&epar, "%s.dir%s%s%s", par, DIR_SEPARATOR_STR, uni, ext);
  GNUNET_free (par);
  return epar;
}


/**
 * Synchronize this download struct with its mirror
 * on disk.  Note that all internal FS-operations that change
 * publishing structs should already call "sync" internally,
 * so this function is likely not useful for clients.
 *
 * @param dc the struct to sync
 */
void
GNUNET_FS_download_sync_ (struct GNUNET_FS_DownloadContext *dc)
{
  struct GNUNET_BIO_WriteHandle *wh;
  char *uris;
  char *fn;
  char *dir;

  if (0 != (dc->options & GNUNET_FS_DOWNLOAD_IS_PROBE))
    return; /* we don't sync probes */
  if (NULL == dc->serialization)
  {
    dir = get_download_sync_filename (dc, "", "");
    if (NULL == dir)
      return;
    if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (dir))
    {
      GNUNET_free (dir);
      return;
    }
    fn = GNUNET_DISK_mktemp (dir);
    GNUNET_free (dir);
    if (NULL == fn)
      return;
    dc->serialization = get_serialization_short_name (fn);
  }
  else
  {
    fn = get_download_sync_filename (dc, dc->serialization, "");
    if (NULL == fn)
    {
      GNUNET_free (dc->serialization);
      dc->serialization = NULL;
      GNUNET_free (fn);
      return;
    }
  }
  wh = GNUNET_BIO_write_open_file (fn);
  if (NULL == wh)
  {
    GNUNET_free (dc->serialization);
    dc->serialization = NULL;
    GNUNET_free (fn);
    return;
  }
  GNUNET_assert ((GNUNET_YES == GNUNET_FS_uri_test_chk (dc->uri)) ||
                 (GNUNET_YES == GNUNET_FS_uri_test_loc (dc->uri)));
  uris = GNUNET_FS_uri_to_string (dc->uri);
  struct GNUNET_BIO_WriteSpec ws1[] = {
    GNUNET_BIO_write_spec_string ("uris", uris),
    GNUNET_BIO_write_spec_meta_data ("metadata", dc->meta),
    GNUNET_BIO_write_spec_string ("emsg", dc->emsg),
    GNUNET_BIO_write_spec_string ("filename", dc->filename),
    GNUNET_BIO_write_spec_string ("temp filename", dc->temp_filename),
    GNUNET_BIO_write_spec_int64 ("old file size",
                                 (int64_t *) &dc->old_file_size),
    GNUNET_BIO_write_spec_int64 ("offset", (int64_t *) &dc->offset),
    GNUNET_BIO_write_spec_int64 ("length", (int64_t *) &dc->length),
    GNUNET_BIO_write_spec_int64 ("completed", (int64_t *) &dc->completed),
    GNUNET_BIO_write_spec_end (),
  };
  struct GNUNET_BIO_WriteSpec ws2[] = {
    GNUNET_BIO_write_spec_int32 ("anonymity", (int32_t *) &dc->anonymity),
    GNUNET_BIO_write_spec_int32 ("options", (int32_t *) &dc->options),
    GNUNET_BIO_write_spec_int32 ("has finished", (int32_t *) &dc->has_finished),
    GNUNET_BIO_write_spec_end (),
  };
  if ((GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws1)) ||
      (GNUNET_OK != write_start_time (wh, dc->start_time)) ||
      (GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws2)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (NULL == dc->emsg)
  {
    GNUNET_assert (dc->top_request != NULL);
    if (GNUNET_YES != write_download_request (wh, dc->top_request))
    {
      GNUNET_break (0);
      goto cleanup;
    }
  }
  GNUNET_free (uris);
  uris = NULL;
  if (GNUNET_OK != GNUNET_BIO_write_close (wh, NULL))
  {
    wh = NULL;
    GNUNET_break (0);
    goto cleanup;
  }
  GNUNET_free (fn);
  return;
cleanup:
  if (NULL != wh)
    (void) GNUNET_BIO_write_close (wh, NULL);
  GNUNET_free (uris);
  if (0 != unlink (fn))
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", fn);
  GNUNET_free (fn);
  GNUNET_free (dc->serialization);
  dc->serialization = NULL;
}


/**
 * Synchronize this search result with its mirror
 * on disk.  Note that all internal FS-operations that change
 * publishing structs should already call "sync" internally,
 * so this function is likely not useful for clients.
 *
 * @param sr the struct to sync
 */
void
GNUNET_FS_search_result_sync_ (struct GNUNET_FS_SearchResult *sr)
{
  struct GNUNET_BIO_WriteHandle *wh;
  char *uris;

  if (NULL == sr->sc)
    return;
  uris = NULL;
  if (NULL == sr->serialization)
    sr->serialization =
      make_serialization_file_name_in_dir (sr->h,
                                           (sr->sc->psearch_result == NULL)
                                           ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
                                           : GNUNET_FS_SYNC_PATH_CHILD_SEARCH,
                                           sr->sc->serialization);
  if (NULL == sr->serialization)
    return;
  wh = get_write_handle_in_dir (sr->h,
                                (sr->sc->psearch_result == NULL)
                                ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
                                : GNUNET_FS_SYNC_PATH_CHILD_SEARCH,
                                sr->sc->serialization,
                                sr->serialization);
  if (NULL == wh)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  uris = GNUNET_FS_uri_to_string (sr->uri);
  struct GNUNET_BIO_WriteSpec ws[] = {
    GNUNET_BIO_write_spec_string ("uris", uris),
    GNUNET_BIO_write_spec_string ("download serialization",
                                  (sr->download != NULL)
                                  ? sr->download->serialization
                                  : NULL),
    GNUNET_BIO_write_spec_string ("update search serialization",
                                  (sr->update_search != NULL)
                                  ? sr->update_search->serialization
                                  : NULL),
    GNUNET_BIO_write_spec_meta_data ("metadata", sr->meta),
    GNUNET_BIO_write_spec_object ("key", &sr->key,
                                  sizeof(struct GNUNET_HashCode)),
    GNUNET_BIO_write_spec_int32 ("mandatory missing",
                                 (int32_t *) &sr->mandatory_missing),
    GNUNET_BIO_write_spec_int32 ("optional support",
                                 (int32_t *) &sr->optional_support),
    GNUNET_BIO_write_spec_int32 ("availability success",
                                 (int32_t *) &sr->availability_success),
    GNUNET_BIO_write_spec_int32 ("availability trials",
                                 (int32_t *) &sr->availability_trials),
    GNUNET_BIO_write_spec_end (),
  };
  if ((GNUNET_OK != GNUNET_BIO_write_spec_commit (wh, ws)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if ((NULL != sr->uri) && (GNUNET_FS_URI_KSK == sr->sc->uri->type) &&
      (GNUNET_OK !=
       GNUNET_BIO_write (wh,
                         "keyword bitmap",
                         sr->keyword_bitmap,
                         (sr->sc->uri->data.ksk.keywordCount + 7) / 8)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (GNUNET_OK != GNUNET_BIO_write_close (wh, NULL))
  {
    wh = NULL;
    GNUNET_break (0);
    goto cleanup;
  }
  GNUNET_free (uris);
  return;
cleanup:
  GNUNET_free (uris);
  if (NULL != wh)
    (void) GNUNET_BIO_write_close (wh, NULL);
  remove_sync_file_in_dir (sr->h,
                           (NULL == sr->sc->psearch_result)
                           ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
                           : GNUNET_FS_SYNC_PATH_CHILD_SEARCH,
                           sr->sc->serialization,
                           sr->serialization);
  GNUNET_free (sr->serialization);
  sr->serialization = NULL;
}


/**
 * Synchronize this search struct with its mirror
 * on disk.  Note that all internal FS-operations that change
 * publishing structs should already call "sync" internally,
 * so this function is likely not useful for clients.
 *
 * @param sc the struct to sync
 */
void
GNUNET_FS_search_sync_ (struct GNUNET_FS_SearchContext *sc)
{
  struct GNUNET_BIO_WriteHandle *wh;
  char *uris;
  char in_pause;
  const char *category;

  category = (NULL == sc->psearch_result) ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
             : GNUNET_FS_SYNC_PATH_CHILD_SEARCH;
  if (NULL == sc->serialization)
    sc->serialization = make_serialization_file_name (sc->h, category);
  if (NULL == sc->serialization)
    return;
  uris = NULL;
  wh = get_write_handle (sc->h, category, sc->serialization);
  if (NULL == wh)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  GNUNET_assert ((GNUNET_YES == GNUNET_FS_uri_test_ksk (sc->uri)) ||
                 (GNUNET_YES == GNUNET_FS_uri_test_sks (sc->uri)));
  uris = GNUNET_FS_uri_to_string (sc->uri);
  in_pause = (sc->task != NULL) ? 'r' : '\0';
  if ((GNUNET_OK != GNUNET_BIO_write_string (wh, "uris", uris)) ||
      (GNUNET_OK != write_start_time (wh, sc->start_time)) ||
      (GNUNET_OK != GNUNET_BIO_write_string (wh, "emsg", sc->emsg)) ||
      (GNUNET_OK != GNUNET_BIO_write_int32 (wh, "options",
                                            (uint32_t) sc->options)) ||
      (GNUNET_OK != GNUNET_BIO_write (wh, "in pause",
                                      &in_pause, sizeof(in_pause))) ||
      (GNUNET_OK != GNUNET_BIO_write_int32 (wh, "anonymity", sc->anonymity)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  GNUNET_free (uris);
  uris = NULL;
  if (GNUNET_OK != GNUNET_BIO_write_close (wh, NULL))
  {
    wh = NULL;
    GNUNET_break (0);
    goto cleanup;
  }
  return;
cleanup:
  if (NULL != wh)
    (void) GNUNET_BIO_write_close (wh, NULL);
  GNUNET_free (uris);
  GNUNET_FS_remove_sync_file_ (sc->h, category, sc->serialization);
  GNUNET_free (sc->serialization);
  sc->serialization = NULL;
}


/**
 * Function called with a filename of serialized unindexing operation
 * to deserialize.
 *
 * @param cls the `struct GNUNET_FS_Handle *`
 * @param filename complete filename (absolute path)
 * @return #GNUNET_OK (continue to iterate)
 */
static int
deserialize_unindex_file (void *cls, const char *filename)
{
  struct GNUNET_FS_Handle *h = cls;
  struct GNUNET_BIO_ReadHandle *rh;
  struct GNUNET_FS_UnindexContext *uc;
  struct GNUNET_FS_ProgressInfo pi;
  char *emsg;
  char *uris;
  uint32_t state;

  uc = GNUNET_new (struct GNUNET_FS_UnindexContext);
  uc->h = h;
  uc->serialization = get_serialization_short_name (filename);
  rh = GNUNET_BIO_read_open_file (filename);
  if (NULL == rh)
  {
    GNUNET_break (0);
    goto cleanup;
  }
  uris = NULL;
  if ((GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "unindex-fn", &uc->filename, 10 * 1024)) ||
      (GNUNET_OK != GNUNET_BIO_read_int64 (rh, "file size",
                                           (int64_t *) &uc->file_size)) ||
      (GNUNET_OK != read_start_time (rh, &uc->start_time)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "state",
                                           (int32_t *) &state)) ||
      (GNUNET_OK !=
       GNUNET_BIO_read (rh, "uri", &uc->chk, sizeof(struct ContentHashKey))) ||
      (GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "unindex-kskuri", &uris, 10 * 1024)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "ksk offset",
                                           (int32_t *) &uc->ksk_offset)))
  {
    GNUNET_free (uris);
    GNUNET_break (0);
    goto cleanup;
  }
  if (NULL != uris)
  {
    uc->ksk_uri = GNUNET_FS_uri_parse (uris, &emsg);
    GNUNET_free (uris);
    if (NULL == uc->ksk_uri)
    {
      GNUNET_break (0);
      GNUNET_free (emsg);
      goto cleanup;
    }
  }
  if ((uc->ksk_offset > 0) &&
      ((NULL == uc->ksk_uri) ||
       (uc->ksk_offset > uc->ksk_uri->data.ksk.keywordCount)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  uc->state = (enum UnindexState) state;
  switch (state)
  {
  case UNINDEX_STATE_HASHING:
    break;

  case UNINDEX_STATE_FS_NOTIFY:
    if (GNUNET_OK != GNUNET_BIO_read (rh,
                                      "unindex-hash",
                                      &uc->file_id,
                                      sizeof(struct GNUNET_HashCode)))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    break;

  case UNINDEX_STATE_DS_REMOVE:
  case UNINDEX_STATE_EXTRACT_KEYWORDS:
  case UNINDEX_STATE_DS_REMOVE_KBLOCKS:
    break;

  case UNINDEX_STATE_COMPLETE:
    break;

  case UNINDEX_STATE_ERROR:
    if (GNUNET_OK !=
        GNUNET_BIO_read_string (rh, "unindex-emsg", &uc->emsg, 10 * 1024))
    {
      GNUNET_break (0);
      goto cleanup;
    }
    break;

  default:
    GNUNET_break (0);
    goto cleanup;
  }
  uc->top = GNUNET_FS_make_top (h, &GNUNET_FS_unindex_signal_suspend_, uc);
  pi.status = GNUNET_FS_STATUS_UNINDEX_RESUME;
  pi.value.unindex.specifics.resume.message = uc->emsg;
  GNUNET_FS_unindex_make_status_ (&pi,
                                  uc,
                                  (uc->state == UNINDEX_STATE_COMPLETE)
                                  ? uc->file_size
                                  : 0);
  switch (uc->state)
  {
  case UNINDEX_STATE_HASHING:
    uc->fhc = GNUNET_CRYPTO_hash_file (GNUNET_SCHEDULER_PRIORITY_IDLE,
                                       uc->filename,
                                       HASHING_BLOCKSIZE,
                                       &GNUNET_FS_unindex_process_hash_,
                                       uc);
    break;

  case UNINDEX_STATE_FS_NOTIFY:
    uc->state = UNINDEX_STATE_HASHING;
    GNUNET_FS_unindex_process_hash_ (uc, &uc->file_id);
    break;

  case UNINDEX_STATE_DS_REMOVE:
    GNUNET_FS_unindex_do_remove_ (uc);
    break;

  case UNINDEX_STATE_EXTRACT_KEYWORDS:
    GNUNET_FS_unindex_do_extract_keywords_ (uc);
    break;

  case UNINDEX_STATE_DS_REMOVE_KBLOCKS:
    GNUNET_FS_unindex_do_remove_kblocks_ (uc);
    break;

  case UNINDEX_STATE_COMPLETE:
  case UNINDEX_STATE_ERROR:
    /* no need to resume any operation, we were done */
    break;

  default:
    break;
  }
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failure while resuming unindexing operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  return GNUNET_OK;
cleanup:
  GNUNET_free (uc->filename);
  if ((NULL != rh) && (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg)))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failed to resume unindexing operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  if (NULL != uc->serialization)
    GNUNET_FS_remove_sync_file_ (h,
                                 GNUNET_FS_SYNC_PATH_MASTER_UNINDEX,
                                 uc->serialization);
  GNUNET_free (uc->serialization);
  GNUNET_free (uc);
  return GNUNET_OK;
}


/**
 * Deserialize a download.
 *
 * @param h overall context
 * @param rh file to deserialize from
 * @param parent parent download
 * @param search associated search
 * @param serialization name under which the search was serialized
 */
static void
deserialize_download (struct GNUNET_FS_Handle *h,
                      struct GNUNET_BIO_ReadHandle *rh,
                      struct GNUNET_FS_DownloadContext *parent,
                      struct GNUNET_FS_SearchResult *search,
                      const char *serialization);


/**
 * Deserialize a search.
 *
 * @param h overall context
 * @param rh file to deserialize from
 * @param psearch_result parent search result
 * @param serialization name under which the search was serialized
 */
static struct GNUNET_FS_SearchContext *
deserialize_search (struct GNUNET_FS_Handle *h,
                    struct GNUNET_BIO_ReadHandle *rh,
                    struct GNUNET_FS_SearchResult *psearch_result,
                    const char *serialization);


/**
 * Function called with a filename of serialized search result
 * to deserialize.
 *
 * @param cls the `struct GNUNET_FS_SearchContext *`
 * @param filename complete filename (absolute path)
 * @return #GNUNET_OK (continue to iterate)
 */
static int
deserialize_search_result (void *cls, const char *filename)
{
  struct GNUNET_FS_SearchContext *sc = cls;
  char *ser;
  char *uris;
  char *emsg;
  char *download;
  char *update_srch;
  struct GNUNET_BIO_ReadHandle *rh;
  struct GNUNET_BIO_ReadHandle *drh;
  struct GNUNET_FS_SearchResult *sr;

  ser = get_serialization_short_name (filename);
  rh = GNUNET_BIO_read_open_file (filename);
  if (NULL == rh)
  {
    if (NULL != ser)
    {
      remove_sync_file_in_dir (sc->h,
                               (NULL == sc->psearch_result)
                               ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
                               : GNUNET_FS_SYNC_PATH_CHILD_SEARCH,
                               sc->serialization,
                               ser);
      GNUNET_free (ser);
    }
    return GNUNET_OK;
  }
  emsg = NULL;
  uris = NULL;
  download = NULL;
  update_srch = NULL;
  sr = GNUNET_new (struct GNUNET_FS_SearchResult);
  sr->h = sc->h;
  sr->sc = sc;
  sr->serialization = ser;
  if ((GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "result-uri", &uris, 10 * 1024)) ||
      (NULL == (sr->uri = GNUNET_FS_uri_parse (uris, &emsg))) ||
      (GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "download-lnk", &download, 16)) ||
      (GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "search-lnk", &update_srch, 16)) ||
      (GNUNET_OK != GNUNET_BIO_read_meta_data (rh, "result-meta", &sr->meta)) ||
      (GNUNET_OK != GNUNET_BIO_read (rh,
                                     "result-key",
                                     &sr->key,
                                     sizeof(struct GNUNET_HashCode))) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (
         rh,
         "mandatory missing",
         (int32_t *) &sr->mandatory_missing)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (
         rh,
         "optional support",
         (int32_t *) &sr->optional_support)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (
         rh,
         "availability success",
         (int32_t *) &sr->availability_success)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (
         rh,
         "availability trials",
         (int32_t *) &sr->availability_trials)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  if (GNUNET_FS_URI_KSK == sr->sc->uri->type)
  {
    sr->keyword_bitmap = GNUNET_malloc (
      (sr->sc->uri->data.ksk.keywordCount + 7) / 8);   /* round up, count bits */
    if (GNUNET_OK !=
        GNUNET_BIO_read (rh,
                         "keyword-bitmap",
                         sr->keyword_bitmap,
                         (sr->sc->uri->data.ksk.keywordCount + 7) / 8))
    {
      GNUNET_break (0);
      goto cleanup;
    }
  }
  GNUNET_free (uris);
  if (NULL != download)
  {
    drh = get_read_handle (sc->h, GNUNET_FS_SYNC_PATH_CHILD_DOWNLOAD, download);
    if (NULL != drh)
    {
      deserialize_download (sc->h, drh, NULL, sr, download);
      if (GNUNET_OK != GNUNET_BIO_read_close (drh, &emsg))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    _ ("Failed to resume sub-download `%s': %s\n"),
                    download,
                    emsg);
        GNUNET_free (emsg);
      }
    }
    GNUNET_free (download);
  }
  if (NULL != update_srch)
  {
    drh =
      get_read_handle (sc->h, GNUNET_FS_SYNC_PATH_CHILD_SEARCH, update_srch);
    if (NULL != drh)
    {
      deserialize_search (sc->h, drh, sr, update_srch);
      if (GNUNET_OK != GNUNET_BIO_read_close (drh, &emsg))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    _ ("Failed to resume sub-search `%s': %s\n"),
                    update_srch,
                    emsg);
        GNUNET_free (emsg);
      }
    }
    GNUNET_free (update_srch);
  }
  GNUNET_break (GNUNET_YES == GNUNET_CONTAINER_multihashmap_put (
                  sc->master_result_map,
                  &sr->key,
                  sr,
                  GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE));
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failure while resuming search operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  return GNUNET_OK;
cleanup:
  GNUNET_free (download);
  GNUNET_free (emsg);
  GNUNET_free (uris);
  GNUNET_free (update_srch);
  if (NULL != sr->uri)
    GNUNET_FS_uri_destroy (sr->uri);
  if (NULL != sr->meta)
    GNUNET_CONTAINER_meta_data_destroy (sr->meta);
  GNUNET_free (sr->serialization);
  GNUNET_free (sr);
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failure while resuming search operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  return GNUNET_OK;
}


/**
 * Send the 'resume' signal to the callback; also actually
 * resume the download (put it in the queue).  Does this
 * recursively for the top-level download and all child
 * downloads.
 *
 * @param dc download to resume
 */
static void
signal_download_resume (struct GNUNET_FS_DownloadContext *dc)
{
  struct GNUNET_FS_DownloadContext *dcc;
  struct GNUNET_FS_ProgressInfo pi;

  pi.status = GNUNET_FS_STATUS_DOWNLOAD_RESUME;
  pi.value.download.specifics.resume.meta = dc->meta;
  pi.value.download.specifics.resume.message = dc->emsg;
  GNUNET_FS_download_make_status_ (&pi, dc);
  dcc = dc->child_head;
  while (NULL != dcc)
  {
    signal_download_resume (dcc);
    dcc = dcc->next;
  }
}


/**
 * Signal resuming of a search to our clients (for the
 * top level search and all sub-searches).
 *
 * @param sc search being resumed
 */
static void
signal_search_resume (struct GNUNET_FS_SearchContext *sc);


/**
 * Iterator over search results signaling resume to the client for
 * each result.
 *
 * @param cls closure, the `struct GNUNET_FS_SearchContext *`
 * @param key current key code
 * @param value value in the hash map, the `struct GNUNET_FS_SearchResult *`
 * @return #GNUNET_YES (we should continue to iterate)
 */
static int
signal_result_resume (void *cls, const struct GNUNET_HashCode *key, void *value)
{
  struct GNUNET_FS_SearchContext *sc = cls;
  struct GNUNET_FS_ProgressInfo pi;
  struct GNUNET_FS_SearchResult *sr = value;

  if (0 == sr->mandatory_missing)
  {
    pi.status = GNUNET_FS_STATUS_SEARCH_RESUME_RESULT;
    pi.value.search.specifics.resume_result.meta = sr->meta;
    pi.value.search.specifics.resume_result.uri = sr->uri;
    pi.value.search.specifics.resume_result.result = sr;
    pi.value.search.specifics.resume_result.availability_rank =
      2 * sr->availability_success - sr->availability_trials;
    pi.value.search.specifics.resume_result.availability_certainty =
      sr->availability_trials;
    pi.value.search.specifics.resume_result.applicability_rank =
      sr->optional_support;
    sr->client_info = GNUNET_FS_search_make_status_ (&pi, sc->h, sc);
  }
  if (NULL != sr->download)
  {
    signal_download_resume (sr->download);
  }
  else
  {
    GNUNET_FS_search_start_probe_ (sr);
  }
  if (NULL != sr->update_search)
    signal_search_resume (sr->update_search);
  return GNUNET_YES;
}


/**
 * Free memory allocated by the search context and its children
 *
 * @param sc search context to free
 */
static void
free_search_context (struct GNUNET_FS_SearchContext *sc);


/**
 * Iterator over search results freeing each.
 *
 * @param cls closure, the `struct GNUNET_FS_SearchContext *`
 * @param key current key code
 * @param value value in the hash map, the `struct GNUNET_FS_SearchResult *`
 * @return #GNUNET_YES (we should continue to iterate)
 */
static int
free_result (void *cls, const struct GNUNET_HashCode *key, void *value)
{
  struct GNUNET_FS_SearchResult *sr = value;

  if (NULL != sr->update_search)
  {
    free_search_context (sr->update_search);
    GNUNET_assert (NULL == sr->update_search);
  }
  GNUNET_CONTAINER_meta_data_destroy (sr->meta);
  GNUNET_FS_uri_destroy (sr->uri);
  GNUNET_free (sr);
  return GNUNET_YES;
}


/**
 * Free memory allocated by the search context and its children
 *
 * @param sc search context to free
 */
static void
free_search_context (struct GNUNET_FS_SearchContext *sc)
{
  if (NULL != sc->serialization)
  {
    GNUNET_FS_remove_sync_file_ (sc->h,
                                 (sc->psearch_result == NULL)
                                 ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
                                 : GNUNET_FS_SYNC_PATH_CHILD_SEARCH,
                                 sc->serialization);
    GNUNET_FS_remove_sync_dir_ (sc->h,
                                (sc->psearch_result == NULL)
                                ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
                                : GNUNET_FS_SYNC_PATH_CHILD_SEARCH,
                                sc->serialization);
  }
  GNUNET_free (sc->serialization);
  GNUNET_free (sc->emsg);
  if (NULL != sc->uri)
    GNUNET_FS_uri_destroy (sc->uri);
  if (NULL != sc->master_result_map)
  {
    GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
                                           &free_result,
                                           sc);
    GNUNET_CONTAINER_multihashmap_destroy (sc->master_result_map);
  }
  GNUNET_free (sc);
}


/**
 * Function called with a filename of serialized sub-download
 * to deserialize.
 *
 * @param cls the `struct GNUNET_FS_DownloadContext *` (parent)
 * @param filename complete filename (absolute path)
 * @return #GNUNET_OK (continue to iterate)
 */
static int
deserialize_subdownload (void *cls, const char *filename)
{
  struct GNUNET_FS_DownloadContext *parent = cls;
  char *ser;
  char *emsg;
  struct GNUNET_BIO_ReadHandle *rh;

  ser = get_serialization_short_name (filename);
  rh = GNUNET_BIO_read_open_file (filename);
  if (NULL == rh)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ (
                  "Failed to resume sub-download `%s': could not open file `%s'\n"),
                ser,
                filename);
    GNUNET_free (ser);
    return GNUNET_OK;
  }
  deserialize_download (parent->h, rh, parent, NULL, ser);
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failed to resume sub-download `%s': %s\n"),
                ser,
                emsg);
    GNUNET_free (emsg);
  }
  GNUNET_free (ser);
  return GNUNET_OK;
}


/**
 * Free this download context and all of its descendants.
 * (only works during deserialization since not all possible
 * state it taken care of).
 *
 * @param dc context to free
 */
static void
free_download_context (struct GNUNET_FS_DownloadContext *dc)
{
  struct GNUNET_FS_DownloadContext *dcc;

  if (NULL != dc->meta)
    GNUNET_CONTAINER_meta_data_destroy (dc->meta);
  if (NULL != dc->uri)
    GNUNET_FS_uri_destroy (dc->uri);
  GNUNET_free (dc->temp_filename);
  GNUNET_free (dc->emsg);
  GNUNET_free (dc->filename);
  GNUNET_free (dc->serialization);
  while (NULL != (dcc = dc->child_head))
  {
    GNUNET_CONTAINER_DLL_remove (dc->child_head, dc->child_tail, dcc);
    free_download_context (dcc);
  }
  GNUNET_FS_free_download_request_ (dc->top_request);
  if (NULL != dc->active)
    GNUNET_CONTAINER_multihashmap_destroy (dc->active);
  GNUNET_free (dc);
}


/**
 * Deserialize a download.
 *
 * @param h overall context
 * @param rh file to deserialize from
 * @param parent parent download
 * @param search associated search
 * @param serialization name under which the search was serialized
 */
static void
deserialize_download (struct GNUNET_FS_Handle *h,
                      struct GNUNET_BIO_ReadHandle *rh,
                      struct GNUNET_FS_DownloadContext *parent,
                      struct GNUNET_FS_SearchResult *search,
                      const char *serialization)
{
  struct GNUNET_FS_DownloadContext *dc;
  char *emsg;
  char *uris;
  char *dn;
  uint32_t options;
  uint32_t status;

  uris = NULL;
  emsg = NULL;
  dc = GNUNET_new (struct GNUNET_FS_DownloadContext);
  dc->parent = parent;
  dc->h = h;
  dc->serialization = GNUNET_strdup (serialization);
  struct GNUNET_BIO_ReadSpec rs[] = {
    GNUNET_BIO_read_spec_meta_data ("download-meta", &dc->meta),
    GNUNET_BIO_read_spec_string ("download-emsg", &dc->emsg, 10 * 1024),
    GNUNET_BIO_read_spec_string ("download-fn", &dc->filename, 10 * 1024),
    GNUNET_BIO_read_spec_string ("download-tfn",
                                 &dc->temp_filename, 10 * 1024),
    GNUNET_BIO_read_spec_int64 ("old file size",
                                (int64_t *) &dc->old_file_size),
    GNUNET_BIO_read_spec_int64 ("offset",
                                (int64_t *) &dc->offset),
    GNUNET_BIO_read_spec_int64 ("length",
                                (int64_t *) &dc->length),
    GNUNET_BIO_read_spec_int64 ("completed",
                                (int64_t *) &dc->completed),
    GNUNET_BIO_read_spec_end (),
  };
  if ((GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "download-uri", &uris, 10 * 1024)) ||
      (NULL == (dc->uri = GNUNET_FS_uri_parse (uris, &emsg))) ||
      ((GNUNET_YES != GNUNET_FS_uri_test_chk (dc->uri)) &&
       (GNUNET_YES != GNUNET_FS_uri_test_loc (dc->uri))) ||
      (GNUNET_OK != GNUNET_BIO_read_spec_commit (rh, rs)) ||
      (GNUNET_OK != read_start_time (rh, &dc->start_time)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "anonymity",
                                           (int32_t *) &dc->anonymity)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "options",
                                           (int32_t *) &options)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "status",
                                           (int32_t *) &status)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  dc->options = (enum GNUNET_FS_DownloadOptions) options;
  dc->active =
    GNUNET_CONTAINER_multihashmap_create (1 + 2 * (dc->length / DBLOCK_SIZE),
                                          GNUNET_NO);
  dc->has_finished = (int) status;
  dc->treedepth =
    GNUNET_FS_compute_depth (GNUNET_FS_uri_chk_get_file_size (dc->uri));
  if (GNUNET_FS_uri_test_loc (dc->uri))
    GNUNET_assert (GNUNET_OK ==
                   GNUNET_FS_uri_loc_get_peer_identity (dc->uri, &dc->target));
  if (NULL == dc->emsg)
  {
    dc->top_request = read_download_request (rh);
    if (NULL == dc->top_request)
    {
      GNUNET_break (0);
      goto cleanup;
    }
  }
  dn = get_download_sync_filename (dc, dc->serialization, ".dir");
  if (NULL != dn)
  {
    if (GNUNET_YES == GNUNET_DISK_directory_test (dn, GNUNET_YES))
      GNUNET_DISK_directory_scan (dn, &deserialize_subdownload, dc);
    GNUNET_free (dn);
  }
  if (NULL != parent)
  {
    GNUNET_CONTAINER_DLL_insert (parent->child_head, parent->child_tail, dc);
  }
  if (NULL != search)
  {
    dc->search = search;
    search->download = dc;
  }
  if ((NULL == parent) && (NULL == search))
  {
    dc->top =
      GNUNET_FS_make_top (dc->h, &GNUNET_FS_download_signal_suspend_, dc);
    signal_download_resume (dc);
  }
  GNUNET_free (uris);
  GNUNET_assert (NULL == dc->job_queue);
  dc->task = GNUNET_SCHEDULER_add_now (&GNUNET_FS_download_start_task_, dc);
  return;
cleanup:
  GNUNET_free (uris);
  GNUNET_free (emsg);
  free_download_context (dc);
}


/**
 * Signal resuming of a search to our clients (for the
 * top level search and all sub-searches).
 *
 * @param sc search being resumed
 */
static void
signal_search_resume (struct GNUNET_FS_SearchContext *sc)
{
  struct GNUNET_FS_ProgressInfo pi;

  pi.status = GNUNET_FS_STATUS_SEARCH_RESUME;
  pi.value.search.specifics.resume.message = sc->emsg;
  pi.value.search.specifics.resume.is_paused =
    (NULL == sc->mq) ? GNUNET_YES : GNUNET_NO;
  sc->client_info = GNUNET_FS_search_make_status_ (&pi, sc->h, sc);
  GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
                                         &signal_result_resume,
                                         sc);
}


/**
 * Deserialize a search.
 *
 * @param h overall context
 * @param rh file to deserialize from
 * @param psearch_result parent search result
 * @param serialization name under which the search was serialized
 */
static struct GNUNET_FS_SearchContext *
deserialize_search (struct GNUNET_FS_Handle *h,
                    struct GNUNET_BIO_ReadHandle *rh,
                    struct GNUNET_FS_SearchResult *psearch_result,
                    const char *serialization)
{
  struct GNUNET_FS_SearchContext *sc;
  char *emsg;
  char *uris;
  char *dn;
  uint32_t options;
  char in_pause;

  if ((NULL != psearch_result) && (NULL != psearch_result->update_search))
  {
    GNUNET_break (0);
    return NULL;
  }
  uris = NULL;
  emsg = NULL;
  sc = GNUNET_new (struct GNUNET_FS_SearchContext);
  if (NULL != psearch_result)
  {
    sc->psearch_result = psearch_result;
    psearch_result->update_search = sc;
  }
  sc->h = h;
  sc->serialization = GNUNET_strdup (serialization);
  if ((GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "search-uri", &uris, 10 * 1024)) ||
      (NULL == (sc->uri = GNUNET_FS_uri_parse (uris, &emsg))) ||
      ((GNUNET_YES != GNUNET_FS_uri_test_ksk (sc->uri)) &&
       (GNUNET_YES != GNUNET_FS_uri_test_sks (sc->uri))) ||
      (GNUNET_OK != read_start_time (rh, &sc->start_time)) ||
      (GNUNET_OK !=
       GNUNET_BIO_read_string (rh, "search-emsg", &sc->emsg, 10 * 1024)) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "options",
                                           (int32_t *) &options)) ||
      (GNUNET_OK !=
       GNUNET_BIO_read (rh, "search-pause", &in_pause, sizeof(in_pause))) ||
      (GNUNET_OK != GNUNET_BIO_read_int32 (rh, "anonymity",
                                           (int32_t *) &sc->anonymity)))
  {
    GNUNET_break (0);
    goto cleanup;
  }
  sc->options = (enum GNUNET_FS_SearchOptions) options;
  sc->master_result_map = GNUNET_CONTAINER_multihashmap_create (16, GNUNET_NO);
  dn = get_serialization_file_name_in_dir (h,
                                           (NULL == sc->psearch_result)
                                           ? GNUNET_FS_SYNC_PATH_MASTER_SEARCH
                                           : GNUNET_FS_SYNC_PATH_CHILD_SEARCH,
                                           sc->serialization,
                                           "");
  if (NULL != dn)
  {
    if (GNUNET_YES == GNUNET_DISK_directory_test (dn, GNUNET_YES))
      GNUNET_DISK_directory_scan (dn, &deserialize_search_result, sc);
    GNUNET_free (dn);
  }
  if (('\0' == in_pause) &&
      (GNUNET_OK != GNUNET_FS_search_start_searching_ (sc)))
  {
    GNUNET_log (
      GNUNET_ERROR_TYPE_WARNING,
      _ ("Could not resume running search, will resume as paused search\n"));
  }
  signal_search_resume (sc);
  GNUNET_free (uris);
  return sc;
cleanup:
  GNUNET_free (emsg);
  free_search_context (sc);
  GNUNET_free (uris);
  return NULL;
}


/**
 * Function called with a filename of serialized search operation
 * to deserialize.
 *
 * @param cls the `struct GNUNET_FS_Handle *`
 * @param filename complete filename (absolute path)
 * @return #GNUNET_OK (continue to iterate)
 */
static int
deserialize_search_file (void *cls, const char *filename)
{
  struct GNUNET_FS_Handle *h = cls;
  char *ser;
  char *emsg;
  struct GNUNET_BIO_ReadHandle *rh;
  struct GNUNET_FS_SearchContext *sc;
  struct stat buf;

  if (0 != stat (filename, &buf))
  {
    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "stat", filename);
    return GNUNET_OK;
  }
  if (S_ISDIR (buf.st_mode))
    return GNUNET_OK; /* skip directories */
  ser = get_serialization_short_name (filename);
  rh = GNUNET_BIO_read_open_file (filename);
  if (NULL == rh)
  {
    if (NULL != ser)
    {
      GNUNET_FS_remove_sync_file_ (h, GNUNET_FS_SYNC_PATH_MASTER_SEARCH, ser);
      GNUNET_free (ser);
    }
    return GNUNET_OK;
  }
  sc = deserialize_search (h, rh, NULL, ser);
  if (NULL != sc)
    sc->top = GNUNET_FS_make_top (h, &GNUNET_FS_search_signal_suspend_, sc);
  GNUNET_free (ser);
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failure while resuming search operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  return GNUNET_OK;
}


/**
 * Function called with a filename of serialized download operation
 * to deserialize.
 *
 * @param cls the `struct GNUNET_FS_Handle *`
 * @param filename complete filename (absolute path)
 * @return #GNUNET_OK (continue to iterate)
 */
static int
deserialize_download_file (void *cls, const char *filename)
{
  struct GNUNET_FS_Handle *h = cls;
  char *ser;
  char *emsg;
  struct GNUNET_BIO_ReadHandle *rh;

  ser = get_serialization_short_name (filename);
  rh = GNUNET_BIO_read_open_file (filename);
  if (NULL == rh)
  {
    if (0 != unlink (filename))
      GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING, "unlink", filename);
    GNUNET_free (ser);
    return GNUNET_OK;
  }
  deserialize_download (h, rh, NULL, NULL, ser);
  GNUNET_free (ser);
  if (GNUNET_OK != GNUNET_BIO_read_close (rh, &emsg))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failure while resuming download operation `%s': %s\n"),
                filename,
                emsg);
    GNUNET_free (emsg);
  }
  return GNUNET_OK;
}


/**
 * Deserialize informatin about pending operations.
 *
 * @param master_path which master directory should be scanned
 * @param proc function to call for each entry (will get @a h for 'cls')
 * @param h the `struct GNUNET_FS_Handle *`
 */
static void
deserialization_master (const char *master_path,
                        GNUNET_FileNameCallback proc,
                        struct GNUNET_FS_Handle *h)
{
  char *dn;

  dn = get_serialization_file_name (h, master_path, "");
  if (NULL == dn)
    return;
  if (GNUNET_YES == GNUNET_DISK_directory_test (dn, GNUNET_YES))
    GNUNET_DISK_directory_scan (dn, proc, h);
  GNUNET_free (dn);
}


/**
 * Setup a connection to the file-sharing service.
 *
 * @param cfg configuration to use
 * @param client_name unique identifier for this client
 * @param upcb function to call to notify about FS actions
 * @param upcb_cls closure for @a upcb
 * @param flags specific attributes for fs-operations
 * @param ... list of optional options, terminated with #GNUNET_FS_OPTIONS_END
 * @return NULL on error
 */
struct GNUNET_FS_Handle *
GNUNET_FS_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
                 const char *client_name,
                 GNUNET_FS_ProgressCallback upcb,
                 void *upcb_cls,
                 enum GNUNET_FS_Flags flags,
                 ...)
{
  struct GNUNET_FS_Handle *ret;
  enum GNUNET_FS_OPTIONS opt;
  va_list ap;

  ret = GNUNET_new (struct GNUNET_FS_Handle);
  ret->cfg = cfg;
  ret->client_name = GNUNET_strdup (client_name);
  ret->upcb = upcb;
  ret->upcb_cls = upcb_cls;
  ret->flags = flags;
  ret->max_parallel_downloads = DEFAULT_MAX_PARALLEL_DOWNLOADS;
  ret->max_parallel_requests = DEFAULT_MAX_PARALLEL_REQUESTS;
  ret->avg_block_latency =
    GNUNET_TIME_UNIT_MINUTES; /* conservative starting point */
  va_start (ap, flags);
  while (GNUNET_FS_OPTIONS_END !=
         (opt = GNUNET_VA_ARG_ENUM (ap, GNUNET_FS_OPTIONS)))
  {
    switch (opt)
    {
    case GNUNET_FS_OPTIONS_DOWNLOAD_PARALLELISM:
      ret->max_parallel_downloads = va_arg (ap, unsigned int);

      break;

    case GNUNET_FS_OPTIONS_REQUEST_PARALLELISM:
      ret->max_parallel_requests = va_arg (ap, unsigned int);

      break;

    default:
      GNUNET_break (0);
      GNUNET_free (ret->client_name);
      GNUNET_free (ret);
      va_end (ap);
      return NULL;
    }
  }
  va_end (ap);
  if (0 != (GNUNET_FS_FLAGS_PERSISTENCE & flags))
  {
    deserialization_master (GNUNET_FS_SYNC_PATH_MASTER_PUBLISH,
                            &deserialize_publish_file,
                            ret);
    deserialization_master (GNUNET_FS_SYNC_PATH_MASTER_SEARCH,
                            &deserialize_search_file,
                            ret);
    deserialization_master (GNUNET_FS_SYNC_PATH_MASTER_DOWNLOAD,
                            &deserialize_download_file,
                            ret);
    deserialization_master (GNUNET_FS_SYNC_PATH_MASTER_UNINDEX,
                            &deserialize_unindex_file,
                            ret);
  }
  return ret;
}


/**
 * Close our connection with the file-sharing service.
 * The callback given to #GNUNET_FS_start() will no longer be
 * called after this function returns.
 * This function MUST NOT be called from within the
 * callback itself.
 *
 * @param h handle that was returned from #GNUNET_FS_start()
 */
void
GNUNET_FS_stop (struct GNUNET_FS_Handle *h)
{
  while (NULL != h->top_head)
    h->top_head->ssf (h->top_head->ssf_cls);
  if (NULL != h->queue_job)
    GNUNET_SCHEDULER_cancel (h->queue_job);
  GNUNET_free (h->client_name);
  GNUNET_free (h);
}


/* end of fs_api.c */