src/fs/fs_download.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2001, 2002, 2003, 2004, 2005, 2006, 2008, 2009, 2010 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 2, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20 /**
  21  * @file fs/fs_download.c
  22  * @brief download methods
  23  * @author Christian Grothoff
  24  *
  25  * TODO:
  26  * - handle recursive downloads (need directory &
  27  *   fs-level download-parallelism management)
  28  * - handle recursive downloads where directory file is
  29  *   NOT saved on disk (need temporary file instead then!)
  30  * - location URI suppport (can wait, easy)
  31  * - check if blocks exist already (can wait, easy)
  32  * - check if iblocks can be computed from existing blocks (can wait, hard)
  33  * - persistence (can wait)
  34  */
  35 #include "platform.h"
  36 #include "gnunet_constants.h"
  37 #include "gnunet_fs_service.h"
  38 #include "fs.h"
  39 #include "fs_tree.h"
  40
  41 #define DEBUG_DOWNLOAD GNUNET_NO
  42
  43 /**
  44  * We're storing the IBLOCKS after the DBLOCKS on disk (so that we
  45  * only have to truncate the file once we're done).
  46  *
  47  * Given the offset of a block (with respect to the DBLOCKS) and its
  48  * depth, return the offset where we would store this block in the
  49  * file.
  50  *
  51  * @param fsize overall file size
  52  * @param off offset of the block in the file
  53  * @param depth depth of the block in the tree
  54  * @param treedepth maximum depth of the tree
  55  * @return off for DBLOCKS (depth == treedepth),
  56  *         otherwise an offset past the end
  57  *         of the file that does not overlap
  58  *         with the range for any other block
  59  */
  60 static uint64_t
  61 compute_disk_offset (uint64_t fsize,
  62                      uint64_t off,
  63                      unsigned int depth,
  64                      unsigned int treedepth)
  65 {
  66   unsigned int i;
  67   uint64_t lsize; /* what is the size of all IBlocks for depth "i"? */
  68   uint64_t loff; /* where do IBlocks for depth "i" start? */
  69   unsigned int ioff; /* which IBlock corresponds to "off" at depth "i"? */
  70
  71   if (depth == treedepth)
  72     return off;
  73   /* first IBlocks start at the end of file, rounded up
  74      to full DBLOCK_SIZE */
  75   loff = ((fsize + DBLOCK_SIZE - 1) / DBLOCK_SIZE) * DBLOCK_SIZE;
  76   lsize = ( (fsize + DBLOCK_SIZE-1) / DBLOCK_SIZE) * sizeof (struct ContentHashKey);
  77   GNUNET_assert (0 == (off % DBLOCK_SIZE));
  78   ioff = (off / DBLOCK_SIZE);
  79   for (i=treedepth-1;i>depth;i--)
  80     {
  81       loff += lsize;
  82       lsize = (lsize + CHK_PER_INODE - 1) / CHK_PER_INODE;
  83       GNUNET_assert (lsize > 0);
  84       GNUNET_assert (0 == (ioff % CHK_PER_INODE));
  85       ioff /= CHK_PER_INODE;
  86     }
  87   return loff + ioff * sizeof (struct ContentHashKey);
  88 }
  89
  90
  91 /**
  92  * Given a file of the specified treedepth and a block at the given
  93  * offset and depth, calculate the offset for the CHK at the given
  94  * index.
  95  *
  96  * @param offset the offset of the first
  97  *        DBLOCK in the subtree of the
  98  *        identified IBLOCK
  99  * @param depth the depth of the IBLOCK in the tree
 100  * @param treedepth overall depth of the tree
 101  * @param k which CHK in the IBLOCK are we
 102  *        talking about
 103  * @return offset if k=0, otherwise an appropriately
 104  *         larger value (i.e., if depth = treedepth-1,
 105  *         the returned value should be offset+DBLOCK_SIZE)
 106  */
 107 static uint64_t
 108 compute_dblock_offset (uint64_t offset,
 109                        unsigned int depth,
 110                        unsigned int treedepth,
 111                        unsigned int k)
 112 {
 113   unsigned int i;
 114   uint64_t lsize; /* what is the size of the sum of all DBlocks
 115                      that a CHK at depth i corresponds to? */
 116
 117   if (depth == treedepth)
 118     return offset;
 119   lsize = DBLOCK_SIZE;
 120   for (i=treedepth-1;i>depth;i--)
 121     lsize *= CHK_PER_INODE;
 122   return offset + k * lsize;
 123 }
 124
 125
 126 /**
 127  * Fill in all of the generic fields for
 128  * a download event.
 129  *
 130  * @param pi structure to fill in
 131  * @param dc overall download context
 132  */
 133 static void
 134 make_download_status (struct GNUNET_FS_ProgressInfo *pi,
 135                       struct GNUNET_FS_DownloadContext *dc)
 136 {
 137   pi->value.download.dc = dc;
 138   pi->value.download.cctx
 139     = dc->client_info;
 140   pi->value.download.pctx
 141     = (dc->parent == NULL) ? NULL : dc->parent->client_info;
 142   pi->value.download.uri
 143     = dc->uri;
 144   pi->value.download.filename
 145     = dc->filename;
 146   pi->value.download.size
 147     = dc->length;
 148   pi->value.download.duration
 149     = GNUNET_TIME_absolute_get_duration (dc->start_time);
 150   pi->value.download.completed
 151     = dc->completed;
 152   pi->value.download.anonymity
 153     = dc->anonymity;
 154   pi->value.download.eta
 155     = GNUNET_TIME_calculate_eta (dc->start_time,
 156                                  dc->completed,
 157                                  dc->length);
 158 }
 159
 160 /**
 161  * We're ready to transmit a search request to the
 162  * file-sharing service.  Do it.  If there is
 163  * more than one request pending, try to send
 164  * multiple or request another transmission.
 165  *
 166  * @param cls closure
 167  * @param size number of bytes available in buf
 168  * @param buf where the callee should write the message
 169  * @return number of bytes written to buf
 170  */
 171 static size_t
 172 transmit_download_request (void *cls,
 173                            size_t size,
 174                            void *buf);
 175
 176
 177 /**
 178  * Closure for iterator processing results.
 179  */
 180 struct ProcessResultClosure
 181 {
 182
 183   /**
 184    * Hash of data.
 185    */
 186   GNUNET_HashCode query;
 187
 188   /**
 189    * Data found in P2P network.
 190    */
 191   const void *data;
 192
 193   /**
 194    * Our download context.
 195    */
 196   struct GNUNET_FS_DownloadContext *dc;
 197
 198   /**
 199    * Number of bytes in data.
 200    */
 201   size_t size;
 202
 203   /**
 204    * Type of data.
 205    */
 206   uint32_t type;
 207
 208   /**
 209    * Flag to indicate if this block should be stored on disk.
 210    */
 211   int do_store;
 212
 213 };
 214
 215
 216 /**
 217  * Iterator over entries in the pending requests in the 'active' map for the
 218  * reply that we just got.
 219  *
 220  * @param cls closure (our 'struct ProcessResultClosure')
 221  * @param key query for the given value / request
 222  * @param value value in the hash map (a 'struct DownloadRequest')
 223  * @return GNUNET_YES (we should continue to iterate); unless serious error
 224  */
 225 static int
 226 process_result_with_request (void *cls,
 227                              const GNUNET_HashCode * key,
 228                              void *value);
 229
 230
 231
 232 /**
 233  * Schedule the download of the specified block in the tree.
 234  *
 235  * @param dc overall download this block belongs to
 236  * @param chk content-hash-key of the block
 237  * @param offset offset of the block in the file
 238  *         (for IBlocks, the offset is the lowest
 239  *          offset of any DBlock in the subtree under
 240  *          the IBlock)
 241  * @param depth depth of the block, 0 is the root of the tree
 242  */
 243 static void
 244 schedule_block_download (struct GNUNET_FS_DownloadContext *dc,
 245                          const struct ContentHashKey *chk,
 246                          uint64_t offset,
 247                          unsigned int depth)
 248 {
 249   struct DownloadRequest *sm;
 250   uint64_t total;
 251   uint64_t off;
 252   size_t len;
 253   char block[DBLOCK_SIZE];
 254   GNUNET_HashCode key;
 255   struct ProcessResultClosure prc;
 256
 257 #if DEBUG_DOWNLOAD
 258   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 259               "Scheduling download at offset %llu and depth %u for `%s'\n",
 260               (unsigned long long) offset,
 261               depth,
 262               GNUNET_h2s (&chk->query));
 263 #endif
 264   total = GNUNET_ntohll (dc->uri->data.chk.file_length);
 265   off = compute_disk_offset (total,
 266                              offset,
 267                              depth,
 268                              dc->treedepth);
 269   len = GNUNET_FS_tree_calculate_block_size (total,
 270                                              dc->treedepth,
 271                                              offset,
 272                                              depth);
 273   sm = GNUNET_malloc (sizeof (struct DownloadRequest));
 274   sm->chk = *chk;
 275   sm->offset = offset;
 276   sm->depth = depth;
 277   sm->is_pending = GNUNET_YES;
 278   sm->next = dc->pending;
 279   dc->pending = sm;
 280   GNUNET_CONTAINER_multihashmap_put (dc->active,
 281                                      &chk->query,
 282                                      sm,
 283                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
 284
 285   if ( (dc->old_file_size > off) &&
 286        (dc->handle != NULL) &&
 287        (off  ==
 288         GNUNET_DISK_file_seek (dc->handle,
 289                                off,
 290                                GNUNET_DISK_SEEK_SET) ) &&
 291        (len ==
 292         GNUNET_DISK_file_read (dc->handle,
 293                                block,
 294                                len)) )
 295     {
 296       /* FIXME: also check query matches!? */
 297       if (0 == memcmp (&key,
 298                        &chk->key,
 299                        sizeof (GNUNET_HashCode)))
 300         {
 301           char enc[len];
 302           struct GNUNET_CRYPTO_AesSessionKey sk;
 303           struct GNUNET_CRYPTO_AesInitializationVector iv;
 304           GNUNET_HashCode query;
 305
 306           GNUNET_CRYPTO_hash_to_aes_key (&key, &sk, &iv);
 307           GNUNET_CRYPTO_aes_encrypt (block, len,
 308                                      &sk,
 309                                      &iv,
 310                                      enc);
 311           GNUNET_CRYPTO_hash (enc, len, &query);
 312           if (0 == memcmp (&query,
 313                            &chk->query,
 314                            sizeof (GNUNET_HashCode)))
 315             {
 316               /* already got it! */
 317               prc.dc = dc;
 318               prc.data = enc;
 319               prc.size = len;
 320               prc.type = (dc->treedepth == depth)
 321                 ? GNUNET_DATASTORE_BLOCKTYPE_DBLOCK
 322                 : GNUNET_DATASTORE_BLOCKTYPE_IBLOCK;
 323               prc.query = chk->query;
 324               prc.do_store = GNUNET_NO; /* useless */
 325               process_result_with_request (&prc,
 326                                            &key,
 327                                            sm);
 328             }
 329           else
 330             {
 331               GNUNET_break_op (0);
 332             }
 333           return;
 334         }
 335     }
 336   if (depth < dc->treedepth)
 337     {
 338       // FIXME: try if we could
 339       // reconstitute this IBLOCK
 340       // from the existing blocks on disk (can wait)
 341       // (read block(s), encode, compare with
 342       // query; if matches, simply return)
 343     }
 344
 345   if ( (dc->th == NULL) &&
 346        (dc->client != NULL) )
 347     dc->th = GNUNET_CLIENT_notify_transmit_ready (dc->client,
 348                                                   sizeof (struct SearchMessage),
 349                                                   GNUNET_CONSTANTS_SERVICE_TIMEOUT,
 350                                                   GNUNET_NO,
 351                                                   &transmit_download_request,
 352                                                   dc);
 353 }
 354
 355
 356
 357 /**
 358  * Suggest a filename based on given metadata.
 359  *
 360  * @param md given meta data
 361  * @return NULL if meta data is useless for suggesting a filename
 362  */
 363 char *
 364 GNUNET_FS_meta_data_suggest_filename (const struct GNUNET_CONTAINER_MetaData *md)
 365 {
 366   static const char *mimeMap[][2] = {
 367     {"application/bz2", ".bz2"},
 368     {"application/gnunet-directory", ".gnd"},
 369     {"application/java", ".class"},
 370     {"application/msword", ".doc"},
 371     {"application/ogg", ".ogg"},
 372     {"application/pdf", ".pdf"},
 373     {"application/pgp-keys", ".key"},
 374     {"application/pgp-signature", ".pgp"},
 375     {"application/postscript", ".ps"},
 376     {"application/rar", ".rar"},
 377     {"application/rtf", ".rtf"},
 378     {"application/xml", ".xml"},
 379     {"application/x-debian-package", ".deb"},
 380     {"application/x-dvi", ".dvi"},
 381     {"applixation/x-flac", ".flac"},
 382     {"applixation/x-gzip", ".gz"},
 383     {"application/x-java-archive", ".jar"},
 384     {"application/x-java-vm", ".class"},
 385     {"application/x-python-code", ".pyc"},
 386     {"application/x-redhat-package-manager", ".rpm"},
 387     {"application/x-rpm", ".rpm"},
 388     {"application/x-tar", ".tar"},
 389     {"application/x-tex-pk", ".pk"},
 390     {"application/x-texinfo", ".texinfo"},
 391     {"application/x-xcf", ".xcf"},
 392     {"application/x-xfig", ".xfig"},
 393     {"application/zip", ".zip"},
 394
 395     {"audio/midi", ".midi"},
 396     {"audio/mpeg", ".mp3"},
 397     {"audio/real", ".rm"},
 398     {"audio/x-wav", ".wav"},
 399
 400     {"image/gif", ".gif"},
 401     {"image/jpeg", ".jpg"},
 402     {"image/pcx", ".pcx"},
 403     {"image/png", ".png"},
 404     {"image/tiff", ".tiff"},
 405     {"image/x-ms-bmp", ".bmp"},
 406     {"image/x-xpixmap", ".xpm"},
 407
 408     {"text/css", ".css"},
 409     {"text/html", ".html"},
 410     {"text/plain", ".txt"},
 411     {"text/rtf", ".rtf"},
 412     {"text/x-c++hdr", ".h++"},
 413     {"text/x-c++src", ".c++"},
 414     {"text/x-chdr", ".h"},
 415     {"text/x-csrc", ".c"},
 416     {"text/x-java", ".java"},
 417     {"text/x-moc", ".moc"},
 418     {"text/x-pascal", ".pas"},
 419     {"text/x-perl", ".pl"},
 420     {"text/x-python", ".py"},
 421     {"text/x-tex", ".tex"},
 422
 423     {"video/avi", ".avi"},
 424     {"video/mpeg", ".mpeg"},
 425     {"video/quicktime", ".qt"},
 426     {"video/real", ".rm"},
 427     {"video/x-msvideo", ".avi"},
 428     {NULL, NULL},
 429   };
 430   char *ret;
 431   unsigned int i;
 432   char *mime;
 433   char *base;
 434   const char *ext;
 435
 436   ret = GNUNET_CONTAINER_meta_data_get_by_type (md,
 437                                                 EXTRACTOR_METATYPE_FILENAME);
 438   if (ret != NULL)
 439     return ret;
 440   ext = NULL;
 441   mime = GNUNET_CONTAINER_meta_data_get_by_type (md,
 442                                                  EXTRACTOR_METATYPE_MIMETYPE);
 443   if (mime != NULL)
 444     {
 445       i = 0;
 446       while ( (mimeMap[i][0] != NULL) &&
 447               (0 != strcmp (mime, mimeMap[i][0])))
 448         i++;
 449       if (mimeMap[i][1] == NULL)
 450         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG |
 451                     GNUNET_ERROR_TYPE_BULK,
 452                     _("Did not find mime type `%s' in extension list.\n"),
 453                     mime);
 454       else
 455         ext = mimeMap[i][1];
 456       GNUNET_free (mime);
 457     }
 458   base = GNUNET_CONTAINER_meta_data_get_first_by_types (md,
 459                                                         EXTRACTOR_METATYPE_TITLE,
 460                                                         EXTRACTOR_METATYPE_BOOK_TITLE,
 461                                                         EXTRACTOR_METATYPE_ORIGINAL_TITLE,
 462                                                         EXTRACTOR_METATYPE_PACKAGE_NAME,
 463                                                         EXTRACTOR_METATYPE_URL,
 464                                                         EXTRACTOR_METATYPE_URI,
 465                                                         EXTRACTOR_METATYPE_DESCRIPTION,
 466                                                         EXTRACTOR_METATYPE_ISRC,
 467                                                         EXTRACTOR_METATYPE_JOURNAL_NAME,
 468                                                         EXTRACTOR_METATYPE_AUTHOR_NAME,
 469                                                         EXTRACTOR_METATYPE_SUBJECT,
 470                                                         EXTRACTOR_METATYPE_ALBUM,
 471                                                         EXTRACTOR_METATYPE_ARTIST,
 472                                                         EXTRACTOR_METATYPE_KEYWORDS,
 473                                                         EXTRACTOR_METATYPE_COMMENT,
 474                                                         EXTRACTOR_METATYPE_UNKNOWN,
 475                                                         -1);
 476   if ( (base == NULL) &&
 477        (ext == NULL) )
 478     return NULL;
 479   if (base == NULL)
 480     return GNUNET_strdup (ext);
 481   if (ext == NULL)
 482     return base;
 483   GNUNET_asprintf (&ret,
 484                    "%s%s",
 485                    base,
 486                    ext);
 487   GNUNET_free (base);
 488   return ret;
 489 }
 490
 491
 492 /**
 493  * We've lost our connection with the FS service.
 494  * Re-establish it and re-transmit all of our
 495  * pending requests.
 496  *
 497  * @param dc download context that is having trouble
 498  */
 499 static void
 500 try_reconnect (struct GNUNET_FS_DownloadContext *dc);
 501
 502
 503 /**
 504  * We found an entry in a directory.  Check if the respective child
 505  * already exists and if not create the respective child download.
 506  *
 507  * @param cls the parent download
 508  * @param filename name of the file in the directory
 509  * @param uri URI of the file (CHK or LOC)
 510  * @param meta meta data of the file
 511  * @param length number of bytes in data
 512  * @param data contents of the file (or NULL if they were not inlined)
 513  */
 514 static void
 515 trigger_recursive_download (void *cls,
 516                             const char *filename,
 517                             const struct GNUNET_FS_Uri *uri,
 518                             const struct GNUNET_CONTAINER_MetaData *meta,
 519                             size_t length,
 520                             const void *data)
 521 {
 522   struct GNUNET_FS_DownloadContext *dc = cls;
 523   struct GNUNET_FS_DownloadContext *cpos;
 524   struct GNUNET_DISK_FileHandle *fh;
 525   char *fn;
 526   char *us;
 527   char *ext;
 528   char *dn;
 529   char *full_name;
 530
 531   if (NULL == uri)
 532     return; /* entry for the directory itself */
 533   cpos = dc->child_head;
 534   while (cpos != NULL)
 535     {
 536       if ( (GNUNET_FS_uri_test_equal (uri,
 537                                       cpos->uri)) ||
 538            ( (filename != NULL) &&
 539              (0 == strcmp (cpos->filename,
 540                            filename)) ) )
 541         break;
 542       cpos = cpos->next;
 543     }
 544   if (cpos != NULL)
 545     return; /* already exists */
 546   fn = NULL;
 547   if (NULL == filename)
 548     {
 549       fn = GNUNET_FS_meta_data_suggest_filename (meta);
 550       if (fn == NULL)
 551         {
 552           us = GNUNET_FS_uri_to_string (uri);
 553           fn = GNUNET_strdup (&us [strlen (GNUNET_FS_URI_PREFIX
 554                                            GNUNET_FS_URI_CHK_INFIX)]);
 555           GNUNET_free (us);
 556         }
 557       else if (fn[0] == '.')
 558         {
 559           ext = fn;
 560           us = GNUNET_FS_uri_to_string (uri);
 561           GNUNET_asprintf (&fn,
 562                            "%s%s",
 563                            &us[strlen (GNUNET_FS_URI_PREFIX
 564                                        GNUNET_FS_URI_CHK_INFIX)], ext);
 565           GNUNET_free (ext);
 566           GNUNET_free (us);
 567         }
 568       filename = fn;
 569     }
 570   if (dc->filename == NULL)
 571     {
 572       full_name = NULL;
 573     }
 574   else
 575     {
 576       dn = GNUNET_strdup (dc->filename);
 577       GNUNET_break ( (strlen (dn) >= strlen (GNUNET_FS_DIRECTORY_EXT)) &&
 578                      (NULL !=
 579                       strstr (dn + strlen(dn) - strlen(GNUNET_FS_DIRECTORY_EXT),
 580                               GNUNET_FS_DIRECTORY_EXT)) );
 581       if ( (strlen (dn) >= strlen (GNUNET_FS_DIRECTORY_EXT)) &&
 582            (NULL !=
 583             strstr (dn + strlen(dn) - strlen(GNUNET_FS_DIRECTORY_EXT),
 584                     GNUNET_FS_DIRECTORY_EXT)) )
 585         dn[strlen(dn) - strlen (GNUNET_FS_DIRECTORY_EXT)] = '\0';
 586       if ( (GNUNET_YES == GNUNET_FS_meta_data_test_for_directory (meta)) &&
 587            ( (strlen (filename) < strlen (GNUNET_FS_DIRECTORY_EXT)) ||
 588              (NULL ==
 589               strstr (filename + strlen(filename) - strlen(GNUNET_FS_DIRECTORY_EXT),
 590                       GNUNET_FS_DIRECTORY_EXT)) ) )
 591         {
 592           GNUNET_asprintf (&full_name,
 593                            "%s%s%s%s",
 594                            dn,
 595                            DIR_SEPARATOR_STR,
 596                            filename,
 597                            GNUNET_FS_DIRECTORY_EXT);
 598         }
 599       else
 600         {
 601           GNUNET_asprintf (&full_name,
 602                            "%s%s%s",
 603                            dn,
 604                            DIR_SEPARATOR_STR,
 605                            filename);
 606         }
 607       GNUNET_free (dn);
 608     }
 609   if ( (full_name != NULL) &&
 610        (GNUNET_OK !=
 611         GNUNET_DISK_directory_create_for_file (full_name)) )
 612     {
 613       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 614                   _("Failed to create directory for recursive download of `%s'\n"),
 615                   full_name);
 616       GNUNET_free (full_name);
 617       GNUNET_free_non_null (fn);
 618       return;
 619     }
 620
 621   if (data != NULL)
 622     {
 623       if (full_name != NULL)
 624         {
 625           fh = GNUNET_DISK_file_open (full_name,
 626                                       GNUNET_DISK_OPEN_WRITE | GNUNET_DISK_OPEN_TRUNCATE | GNUNET_DISK_OPEN_CREATE,
 627                                       GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE);
 628           if (fh == NULL)
 629             {
 630               GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
 631                                         "open",
 632                                         full_name);
 633               GNUNET_free (full_name);
 634               GNUNET_free_non_null (fn);
 635               return;
 636             }
 637           if (length !=
 638               GNUNET_DISK_file_write (fh,
 639                                       data,
 640                                       length))
 641             {
 642               GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
 643                                         "write",
 644                                         full_name);
 645             }
 646           GNUNET_DISK_file_close (fh);
 647         }
 648       else
 649         {
 650           /* FIXME: generate 'progress' events and move to
 651              instant completion! */
 652           GNUNET_break (0); // FIXME: not implemented
 653         }
 654     }
 655   GNUNET_FS_download_start (dc->h,
 656                             uri,
 657                             meta,
 658                             full_name,
 659                             0,
 660                             GNUNET_FS_uri_chk_get_file_size (uri),
 661                             dc->anonymity,
 662                             dc->options,
 663                             NULL,
 664                             dc);
 665   GNUNET_free_non_null (full_name);
 666   GNUNET_free_non_null (fn);
 667 }
 668
 669
 670 /**
 671  * We're done downloading a directory.  Open the file and
 672  * trigger all of the (remaining) child downloads.
 673  *
 674  * @param dc context of download that just completed
 675  */
 676 static void
 677 full_recursive_download (struct GNUNET_FS_DownloadContext *dc)
 678 {
 679   size_t size;
 680   uint64_t size64;
 681   void *data;
 682   struct GNUNET_DISK_FileHandle *h;
 683   struct GNUNET_DISK_MapHandle *m;
 684
 685   size64 = GNUNET_FS_uri_chk_get_file_size (dc->uri);
 686   size = (size_t) size64;
 687   if (size64 != (uint64_t) size)
 688     {
 689       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 690                   _("Recursive downloads of directories larger than 4 GB are not supported on 32-bit systems\n"));
 691       return;
 692     }
 693   if (dc->filename != NULL)
 694     {
 695       h = GNUNET_DISK_file_open (dc->filename,
 696                                  GNUNET_DISK_OPEN_READ,
 697                                  GNUNET_DISK_PERM_NONE);
 698     }
 699   else
 700     {
 701       /* FIXME: need to initialize (and use) temp_filename
 702          in various places in order for this assertion to
 703          not fail; right now, it will always fail! */
 704       GNUNET_assert (dc->temp_filename != NULL);
 705       h = GNUNET_DISK_file_open (dc->temp_filename,
 706                                  GNUNET_DISK_OPEN_READ,
 707                                  GNUNET_DISK_PERM_NONE);
 708     }
 709   if (h == NULL)
 710     return; /* oops */
 711   data = GNUNET_DISK_file_map (h, &m, GNUNET_DISK_MAP_TYPE_READ, size);
 712   if (data == NULL)
 713     {
 714       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 715                   _("Directory too large for system address space\n"));
 716     }
 717   else
 718     {
 719       GNUNET_FS_directory_list_contents (size,
 720                                          data,
 721                                          0,
 722                                          &trigger_recursive_download,
 723                                          dc);
 724       GNUNET_DISK_file_unmap (m);
 725     }
 726   GNUNET_DISK_file_close (h);
 727   if (dc->filename == NULL)
 728     {
 729       if (0 != UNLINK (dc->temp_filename))
 730         GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
 731                                   "unlink",
 732                                   dc->temp_filename);
 733       GNUNET_free (dc->temp_filename);
 734       dc->temp_filename = NULL;
 735     }
 736 }
 737
 738
 739 /**
 740  * Check if all child-downloads have completed and
 741  * if so, signal completion (and possibly recurse to
 742  * parent).
 743  */
 744 static void
 745 check_completed (struct GNUNET_FS_DownloadContext *dc)
 746 {
 747   struct GNUNET_FS_ProgressInfo pi;
 748   struct GNUNET_FS_DownloadContext *pos;
 749
 750   pos = dc->child_head;
 751   while (pos != NULL)
 752     {
 753       if ( (pos->emsg == NULL) &&
 754            (pos->completed < pos->length) )
 755         return; /* not done yet */
 756       if ( (pos->child_head != NULL) &&
 757            (pos->has_finished != GNUNET_YES) )
 758         return; /* not transitively done yet */
 759       pos = pos->next;
 760     }
 761   dc->has_finished = GNUNET_YES;
 762   /* signal completion */
 763   pi.status = GNUNET_FS_STATUS_DOWNLOAD_COMPLETED;
 764   make_download_status (&pi, dc);
 765   dc->client_info = dc->h->upcb (dc->h->upcb_cls,
 766                                  &pi);
 767   if (dc->parent != NULL)
 768     check_completed (dc->parent);
 769 }
 770
 771
 772 /**
 773  * Iterator over entries in the pending requests in the 'active' map for the
 774  * reply that we just got.
 775  *
 776  * @param cls closure (our 'struct ProcessResultClosure')
 777  * @param key query for the given value / request
 778  * @param value value in the hash map (a 'struct DownloadRequest')
 779  * @return GNUNET_YES (we should continue to iterate); unless serious error
 780  */
 781 static int
 782 process_result_with_request (void *cls,
 783                              const GNUNET_HashCode * key,
 784                              void *value)
 785 {
 786   struct ProcessResultClosure *prc = cls;
 787   struct DownloadRequest *sm = value;
 788   struct GNUNET_FS_DownloadContext *dc = prc->dc;
 789   struct GNUNET_CRYPTO_AesSessionKey skey;
 790   struct GNUNET_CRYPTO_AesInitializationVector iv;
 791   char pt[prc->size];
 792   struct GNUNET_FS_ProgressInfo pi;
 793   uint64_t off;
 794   size_t bs;
 795   size_t app;
 796   int i;
 797   struct ContentHashKey *chk;
 798   char *emsg;
 799
 800   bs = GNUNET_FS_tree_calculate_block_size (GNUNET_ntohll (dc->uri->data.chk.file_length),
 801                                             dc->treedepth,
 802                                             sm->offset,
 803                                             sm->depth);
 804     if (prc->size != bs)
 805     {
 806 #if DEBUG_DOWNLOAD
 807       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 808                   "Internal error or bogus download URI (expected %u bytes, got %u)\n",
 809                   bs,
 810                   prc->size);
 811 #endif
 812       dc->emsg = GNUNET_strdup ("Internal error or bogus download URI");
 813       /* signal error */
 814       pi.status = GNUNET_FS_STATUS_DOWNLOAD_ERROR;
 815       make_download_status (&pi, dc);
 816       pi.value.download.specifics.error.message = dc->emsg;
 817       dc->client_info = dc->h->upcb (dc->h->upcb_cls,
 818                                      &pi);
 819       /* abort all pending requests */
 820       if (NULL != dc->th)
 821         {
 822           GNUNET_CLIENT_notify_transmit_ready_cancel (dc->th);
 823           dc->th = NULL;
 824         }
 825       GNUNET_CLIENT_disconnect (dc->client, GNUNET_NO);
 826       dc->client = NULL;
 827       return GNUNET_NO;
 828     }
 829   GNUNET_assert (GNUNET_YES ==
 830                  GNUNET_CONTAINER_multihashmap_remove (dc->active,
 831                                                        &prc->query,
 832                                                        sm));
 833   GNUNET_CRYPTO_hash_to_aes_key (&sm->chk.key, &skey, &iv);
 834   GNUNET_CRYPTO_aes_decrypt (prc->data,
 835                              prc->size,
 836                              &skey,
 837                              &iv,
 838                              pt);
 839   off = compute_disk_offset (GNUNET_ntohll (dc->uri->data.chk.file_length),
 840                              sm->offset,
 841                              sm->depth,
 842                              dc->treedepth);
 843   /* save to disk */
 844   if ( ( GNUNET_YES == prc->do_store) &&
 845        (NULL != dc->handle) &&
 846        ( (sm->depth == dc->treedepth) ||
 847          (0 == (dc->options & GNUNET_FS_DOWNLOAD_NO_TEMPORARIES)) ) )
 848     {
 849       emsg = NULL;
 850 #if DEBUG_DOWNLOAD
 851       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 852                   "Saving decrypted block to disk at offset %llu\n",
 853                   (unsigned long long) off);
 854 #endif
 855       if ( (off  !=
 856             GNUNET_DISK_file_seek (dc->handle,
 857                                    off,
 858                                    GNUNET_DISK_SEEK_SET) ) )
 859         GNUNET_asprintf (&emsg,
 860                          _("Failed to seek to offset %llu in file `%s': %s\n"),
 861                          (unsigned long long) off,
 862                          dc->filename,
 863                          STRERROR (errno));
 864       else if (prc->size !=
 865                GNUNET_DISK_file_write (dc->handle,
 866                                        pt,
 867                                        prc->size))
 868         GNUNET_asprintf (&emsg,
 869                          _("Failed to write block of %u bytes at offset %llu in file `%s': %s\n"),
 870                          (unsigned int) prc->size,
 871                          (unsigned long long) off,
 872                          dc->filename,
 873                          STRERROR (errno));
 874       if (NULL != emsg)
 875         {
 876           dc->emsg = emsg;
 877           // FIXME: make persistent
 878
 879           /* signal error */
 880           pi.status = GNUNET_FS_STATUS_DOWNLOAD_ERROR;
 881           make_download_status (&pi, dc);
 882           pi.value.download.specifics.error.message = emsg;
 883           dc->client_info = dc->h->upcb (dc->h->upcb_cls,
 884                                          &pi);
 885
 886           /* abort all pending requests */
 887           if (NULL != dc->th)
 888             {
 889               GNUNET_CLIENT_notify_transmit_ready_cancel (dc->th);
 890               dc->th = NULL;
 891             }
 892           GNUNET_CLIENT_disconnect (dc->client, GNUNET_NO);
 893           dc->client = NULL;
 894           GNUNET_free (sm);
 895           return GNUNET_NO;
 896         }
 897     }
 898   if (sm->depth == dc->treedepth)
 899     {
 900       app = prc->size;
 901       if (sm->offset < dc->offset)
 902         {
 903           /* starting offset begins in the middle of pt,
 904              do not count first bytes as progress */
 905           GNUNET_assert (app > (dc->offset - sm->offset));
 906           app -= (dc->offset - sm->offset);
 907         }
 908       if (sm->offset + prc->size > dc->offset + dc->length)
 909         {
 910           /* end of block is after relevant range,
 911              do not count last bytes as progress */
 912           GNUNET_assert (app > (sm->offset + prc->size) - (dc->offset + dc->length));
 913           app -= (sm->offset + prc->size) - (dc->offset + dc->length);
 914         }
 915       dc->completed += app;
 916
 917       /* do recursive download if option is set and either meta data
 918          says it is a directory or if no meta data is given AND filename
 919          ends in '.gnd' (top-level case) */
 920       if ( (0 != (dc->options & GNUNET_FS_DOWNLOAD_OPTION_RECURSIVE)) &&
 921            ( (GNUNET_YES == GNUNET_FS_meta_data_test_for_directory (dc->meta)) ||
 922              ( (dc->meta == NULL) &&
 923                ( (NULL == dc->filename) ||
 924                  ( (strlen (dc->filename) >= strlen (GNUNET_FS_DIRECTORY_EXT)) &&
 925                    (NULL !=
 926                     strstr (dc->filename + strlen(dc->filename) - strlen(GNUNET_FS_DIRECTORY_EXT),
 927                             GNUNET_FS_DIRECTORY_EXT)) ) ) ) ) )
 928         GNUNET_FS_directory_list_contents (prc->size,
 929                                            pt,
 930                                            off,
 931                                            &trigger_recursive_download,
 932                                            dc);
 933
 934     }
 935   pi.status = GNUNET_FS_STATUS_DOWNLOAD_PROGRESS;
 936   make_download_status (&pi, dc);
 937   pi.value.download.specifics.progress.data = pt;
 938   pi.value.download.specifics.progress.offset = sm->offset;
 939   pi.value.download.specifics.progress.data_len = prc->size;
 940   pi.value.download.specifics.progress.depth = sm->depth;
 941   dc->client_info = dc->h->upcb (dc->h->upcb_cls,
 942                                  &pi);
 943   GNUNET_assert (dc->completed <= dc->length);
 944   if (dc->completed == dc->length)
 945     {
 946 #if DEBUG_DOWNLOAD
 947       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 948                   "Download completed, truncating file to desired length %llu\n",
 949                   (unsigned long long) GNUNET_ntohll (dc->uri->data.chk.file_length));
 950 #endif
 951       /* truncate file to size (since we store IBlocks at the end) */
 952       if (dc->handle != NULL)
 953         {
 954           GNUNET_DISK_file_close (dc->handle);
 955           dc->handle = NULL;
 956           if (0 != truncate (dc->filename,
 957                              GNUNET_ntohll (dc->uri->data.chk.file_length)))
 958             GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
 959                                       "truncate",
 960                                       dc->filename);
 961         }
 962
 963       if ( (0 != (dc->options & GNUNET_FS_DOWNLOAD_OPTION_RECURSIVE)) &&
 964            ( (GNUNET_YES == GNUNET_FS_meta_data_test_for_directory (dc->meta)) ||
 965              ( (dc->meta == NULL) &&
 966                ( (NULL == dc->filename) ||
 967                  ( (strlen (dc->filename) >= strlen (GNUNET_FS_DIRECTORY_EXT)) &&
 968                    (NULL !=
 969                     strstr (dc->filename + strlen(dc->filename) - strlen(GNUNET_FS_DIRECTORY_EXT),
 970                             GNUNET_FS_DIRECTORY_EXT)) ) ) ) ) )
 971         full_recursive_download (dc);
 972       if (dc->child_head == NULL)
 973         {
 974           /* signal completion */
 975           pi.status = GNUNET_FS_STATUS_DOWNLOAD_COMPLETED;
 976           make_download_status (&pi, dc);
 977           dc->client_info = dc->h->upcb (dc->h->upcb_cls,
 978                                          &pi);
 979           if (dc->parent != NULL)
 980             check_completed (dc->parent);
 981         }
 982       GNUNET_assert (sm->depth == dc->treedepth);
 983     }
 984   // FIXME: make persistent
 985   if (sm->depth == dc->treedepth)
 986     {
 987       GNUNET_free (sm);
 988       return GNUNET_YES;
 989     }
 990 #if DEBUG_DOWNLOAD
 991   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 992               "Triggering downloads of children (this block was at depth %u and offset %llu)\n",
 993               sm->depth,
 994               (unsigned long long) sm->offset);
 995 #endif
 996   GNUNET_assert (0 == (prc->size % sizeof(struct ContentHashKey)));
 997   chk = (struct ContentHashKey*) pt;
 998   for (i=(prc->size / sizeof(struct ContentHashKey))-1;i>=0;i--)
 999     {
1000       off = compute_dblock_offset (sm->offset,
1001                                    sm->depth,
1002                                    dc->treedepth,
1003                                    i);
1004       if ( (off + DBLOCK_SIZE >= dc->offset) &&
1005            (off < dc->offset + dc->length) )
1006         schedule_block_download (dc,
1007                                  &chk[i],
1008                                  off,
1009                                  sm->depth + 1);
1010     }
1011   GNUNET_free (sm);
1012   return GNUNET_YES;
1013 }
1014
1015
1016 /**
1017  * Process a download result.
1018  *
1019  * @param dc our download context
1020  * @param type type of the result
1021  * @param data the (encrypted) response
1022  * @param size size of data
1023  */
1024 static void
1025 process_result (struct GNUNET_FS_DownloadContext *dc,
1026                 uint32_t type,
1027                 const void *data,
1028                 size_t size)
1029 {
1030   struct ProcessResultClosure prc;
1031
1032   prc.dc = dc;
1033   prc.data = data;
1034   prc.size = size;
1035   prc.type = type;
1036   prc.do_store = GNUNET_YES;
1037   GNUNET_CRYPTO_hash (data, size, &prc.query);
1038 #if DEBUG_DOWNLOAD
1039   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1040               "Received result for query `%s' from `%s'-service\n",
1041               GNUNET_h2s (&prc.query),
1042               "FS");
1043 #endif
1044   GNUNET_CONTAINER_multihashmap_get_multiple (dc->active,
1045                                               &prc.query,
1046                                               &process_result_with_request,
1047                                               &prc);
1048 }
1049
1050
1051 /**
1052  * Type of a function to call when we receive a message
1053  * from the service.
1054  *
1055  * @param cls closure
1056  * @param msg message received, NULL on timeout or fatal error
1057  */
1058 static void
1059 receive_results (void *cls,
1060                  const struct GNUNET_MessageHeader * msg)
1061 {
1062   struct GNUNET_FS_DownloadContext *dc = cls;
1063   const struct PutMessage *cm;
1064   uint16_t msize;
1065
1066   if ( (NULL == msg) ||
1067        (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_FS_PUT) ||
1068        (sizeof (struct PutMessage) > ntohs(msg->size)) )
1069     {
1070       GNUNET_break (msg == NULL);
1071       try_reconnect (dc);
1072       return;
1073     }
1074   msize = ntohs(msg->size);
1075   cm = (const struct PutMessage*) msg;
1076   process_result (dc,
1077                   ntohl (cm->type),
1078                   &cm[1],
1079                   msize - sizeof (struct PutMessage));
1080   if (dc->client == NULL)
1081     return; /* fatal error */
1082   /* continue receiving */
1083   GNUNET_CLIENT_receive (dc->client,
1084                          &receive_results,
1085                          dc,
1086                          GNUNET_TIME_UNIT_FOREVER_REL);
1087 }
1088
1089
1090
1091 /**
1092  * We're ready to transmit a search request to the
1093  * file-sharing service.  Do it.  If there is
1094  * more than one request pending, try to send
1095  * multiple or request another transmission.
1096  *
1097  * @param cls closure
1098  * @param size number of bytes available in buf
1099  * @param buf where the callee should write the message
1100  * @return number of bytes written to buf
1101  */
1102 static size_t
1103 transmit_download_request (void *cls,
1104                            size_t size,
1105                            void *buf)
1106 {
1107   struct GNUNET_FS_DownloadContext *dc = cls;
1108   size_t msize;
1109   struct SearchMessage *sm;
1110
1111   dc->th = NULL;
1112   if (NULL == buf)
1113     {
1114       try_reconnect (dc);
1115       return 0;
1116     }
1117   GNUNET_assert (size >= sizeof (struct SearchMessage));
1118   msize = 0;
1119   sm = buf;
1120   while ( (dc->pending != NULL) &&
1121           (size > msize + sizeof (struct SearchMessage)) )
1122     {
1123 #if DEBUG_DOWNLOAD
1124       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1125                   "Transmitting download request for `%s' to `%s'-service\n",
1126                   GNUNET_h2s (&dc->pending->chk.query),
1127                   "FS");
1128 #endif
1129       memset (sm, 0, sizeof (struct SearchMessage));
1130       sm->header.size = htons (sizeof (struct SearchMessage));
1131       sm->header.type = htons (GNUNET_MESSAGE_TYPE_FS_START_SEARCH);
1132       if (dc->pending->depth == dc->treedepth)
1133         sm->type = htonl (GNUNET_DATASTORE_BLOCKTYPE_DBLOCK);
1134       else
1135         sm->type = htonl (GNUNET_DATASTORE_BLOCKTYPE_IBLOCK);
1136       sm->anonymity_level = htonl (dc->anonymity);
1137       sm->target = dc->target.hashPubKey;
1138       sm->query = dc->pending->chk.query;
1139       dc->pending->is_pending = GNUNET_NO;
1140       dc->pending = dc->pending->next;
1141       msize += sizeof (struct SearchMessage);
1142       sm++;
1143     }
1144   if (dc->pending != NULL)
1145     dc->th = GNUNET_CLIENT_notify_transmit_ready (dc->client,
1146                                                   sizeof (struct SearchMessage),
1147                                                   GNUNET_CONSTANTS_SERVICE_TIMEOUT,
1148                                                   GNUNET_NO,
1149                                                   &transmit_download_request,
1150                                                   dc);
1151   return msize;
1152 }
1153
1154
1155 /**
1156  * Reconnect to the FS service and transmit our queries NOW.
1157  *
1158  * @param cls our download context
1159  * @param tc unused
1160  */
1161 static void
1162 do_reconnect (void *cls,
1163               const struct GNUNET_SCHEDULER_TaskContext *tc)
1164 {
1165   struct GNUNET_FS_DownloadContext *dc = cls;
1166   struct GNUNET_CLIENT_Connection *client;
1167
1168   dc->task = GNUNET_SCHEDULER_NO_TASK;
1169   client = GNUNET_CLIENT_connect (dc->h->sched,
1170                                   "fs",
1171                                   dc->h->cfg);
1172   if (NULL == client)
1173     {
1174       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
1175                   "Connecting to `%s'-service failed, will try again.\n",
1176                   "FS");
1177       try_reconnect (dc);
1178       return;
1179     }
1180   dc->client = client;
1181   dc->th = GNUNET_CLIENT_notify_transmit_ready (client,
1182                                                 sizeof (struct SearchMessage),
1183                                                 GNUNET_CONSTANTS_SERVICE_TIMEOUT,
1184                                                 GNUNET_NO,
1185                                                 &transmit_download_request,
1186                                                 dc);
1187   GNUNET_CLIENT_receive (client,
1188                          &receive_results,
1189                          dc,
1190                          GNUNET_TIME_UNIT_FOREVER_REL);
1191 }
1192
1193
1194 /**
1195  * Add entries that are not yet pending back to the pending list.
1196  *
1197  * @param cls our download context
1198  * @param key unused
1199  * @param entry entry of type "struct DownloadRequest"
1200  * @return GNUNET_OK
1201  */
1202 static int
1203 retry_entry (void *cls,
1204              const GNUNET_HashCode *key,
1205              void *entry)
1206 {
1207   struct GNUNET_FS_DownloadContext *dc = cls;
1208   struct DownloadRequest *dr = entry;
1209
1210   if (! dr->is_pending)
1211     {
1212       dr->next = dc->pending;
1213       dr->is_pending = GNUNET_YES;
1214       dc->pending = entry;
1215     }
1216   return GNUNET_OK;
1217 }
1218
1219
1220 /**
1221  * We've lost our connection with the FS service.
1222  * Re-establish it and re-transmit all of our
1223  * pending requests.
1224  *
1225  * @param dc download context that is having trouble
1226  */
1227 static void
1228 try_reconnect (struct GNUNET_FS_DownloadContext *dc)
1229 {
1230
1231   if (NULL != dc->client)
1232     {
1233       if (NULL != dc->th)
1234         {
1235           GNUNET_CLIENT_notify_transmit_ready_cancel (dc->th);
1236           dc->th = NULL;
1237         }
1238       GNUNET_CONTAINER_multihashmap_iterate (dc->active,
1239                                              &retry_entry,
1240                                              dc);
1241       GNUNET_CLIENT_disconnect (dc->client, GNUNET_NO);
1242       dc->client = NULL;
1243     }
1244   dc->task
1245     = GNUNET_SCHEDULER_add_delayed (dc->h->sched,
1246                                     GNUNET_TIME_UNIT_SECONDS,
1247                                     &do_reconnect,
1248                                     dc);
1249 }
1250
1251
1252 /**
1253  * Download parts of a file.  Note that this will store
1254  * the blocks at the respective offset in the given file.  Also, the
1255  * download is still using the blocking of the underlying FS
1256  * encoding.  As a result, the download may *write* outside of the
1257  * given boundaries (if offset and length do not match the 32k FS
1258  * block boundaries). <p>
1259  *
1260  * This function should be used to focus a download towards a
1261  * particular portion of the file (optimization), not to strictly
1262  * limit the download to exactly those bytes.
1263  *
1264  * @param h handle to the file sharing subsystem
1265  * @param uri the URI of the file (determines what to download); CHK or LOC URI
1266  * @param meta known metadata for the file (can be NULL)
1267  * @param filename where to store the file, maybe NULL (then no file is
1268  *        created on disk and data must be grabbed from the callbacks)
1269  * @param offset at what offset should we start the download (typically 0)
1270  * @param length how many bytes should be downloaded starting at offset
1271  * @param anonymity anonymity level to use for the download
1272  * @param options various options
1273  * @param cctx initial value for the client context for this download
1274  * @param parent parent download to associate this download with (use NULL
1275  *        for top-level downloads; useful for manually-triggered recursive downloads)
1276  * @return context that can be used to control this download
1277  */
1278 struct GNUNET_FS_DownloadContext *
1279 GNUNET_FS_download_start (struct GNUNET_FS_Handle *h,
1280                           const struct GNUNET_FS_Uri *uri,
1281                           const struct GNUNET_CONTAINER_MetaData *meta,
1282                           const char *filename,
1283                           uint64_t offset,
1284                           uint64_t length,
1285                           uint32_t anonymity,
1286                           enum GNUNET_FS_DownloadOptions options,
1287                           void *cctx,
1288                           struct GNUNET_FS_DownloadContext *parent)
1289 {
1290   struct GNUNET_FS_ProgressInfo pi;
1291   struct GNUNET_FS_DownloadContext *dc;
1292   struct GNUNET_CLIENT_Connection *client;
1293
1294   GNUNET_assert (GNUNET_FS_uri_test_chk (uri));
1295   if ( (offset + length < offset) ||
1296        (offset + length > uri->data.chk.file_length) )
1297     {
1298       GNUNET_break (0);
1299       return NULL;
1300     }
1301   // FIXME: add support for "loc" URIs!
1302 #if DEBUG_DOWNLOAD
1303   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1304               "Starting download `%s' of %llu bytes\n",
1305               filename,
1306               (unsigned long long) length);
1307 #endif
1308   dc = GNUNET_malloc (sizeof(struct GNUNET_FS_DownloadContext));
1309   dc->h = h;
1310   dc->parent = parent;
1311   if (parent != NULL)
1312     {
1313       GNUNET_CONTAINER_DLL_insert (parent->child_head,
1314                                    parent->child_tail,
1315                                    dc);
1316     }
1317   dc->uri = GNUNET_FS_uri_dup (uri);
1318   dc->meta = GNUNET_CONTAINER_meta_data_duplicate (meta);
1319   dc->client_info = cctx;
1320   dc->start_time = GNUNET_TIME_absolute_get ();
1321   if (NULL != filename)
1322     {
1323       dc->filename = GNUNET_strdup (filename);
1324       if (GNUNET_YES == GNUNET_DISK_file_test (filename))
1325         GNUNET_DISK_file_size (filename,
1326                                &dc->old_file_size,
1327                                GNUNET_YES);
1328       dc->handle = GNUNET_DISK_file_open (filename,
1329                                           GNUNET_DISK_OPEN_READWRITE |
1330                                           GNUNET_DISK_OPEN_CREATE,
1331                                           GNUNET_DISK_PERM_USER_READ |
1332                                           GNUNET_DISK_PERM_USER_WRITE |
1333                                           GNUNET_DISK_PERM_GROUP_READ |
1334                                           GNUNET_DISK_PERM_OTHER_READ);
1335       if (dc->handle == NULL)
1336         {
1337           GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
1338                       _("Download failed: could not open file `%s': %s\n"),
1339                       dc->filename,
1340                       STRERROR (errno));
1341           GNUNET_CONTAINER_meta_data_destroy (dc->meta);
1342           GNUNET_FS_uri_destroy (dc->uri);
1343           GNUNET_free (dc->filename);
1344           GNUNET_free (dc);
1345           return NULL;
1346         }
1347     }
1348   // FIXME: set "dc->target" for LOC uris!
1349   dc->offset = offset;
1350   dc->length = length;
1351   dc->anonymity = anonymity;
1352   dc->options = options;
1353   dc->active = GNUNET_CONTAINER_multihashmap_create (1 + 2 * (length / DBLOCK_SIZE));
1354   dc->treedepth = GNUNET_FS_compute_depth (GNUNET_ntohll(dc->uri->data.chk.file_length));
1355 #if DEBUG_DOWNLOAD
1356   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1357               "Download tree has depth %u\n",
1358               dc->treedepth);
1359 #endif
1360   // FIXME: make persistent
1361
1362   // FIXME: bound parallelism here!
1363   client = GNUNET_CLIENT_connect (h->sched,
1364                                   "fs",
1365                                   h->cfg);
1366   dc->client = client;
1367   schedule_block_download (dc,
1368                            &dc->uri->data.chk.chk,
1369                            0,
1370                            1 /* 0 == CHK, 1 == top */);
1371   GNUNET_CLIENT_receive (client,
1372                          &receive_results,
1373                          dc,
1374                          GNUNET_TIME_UNIT_FOREVER_REL);
1375   pi.status = GNUNET_FS_STATUS_DOWNLOAD_START;
1376   make_download_status (&pi, dc);
1377   pi.value.download.specifics.start.meta = meta;
1378   dc->client_info = dc->h->upcb (dc->h->upcb_cls,
1379                                  &pi);
1380
1381   return dc;
1382 }
1383
1384
1385 /**
1386  * Free entries in the map.
1387  *
1388  * @param cls unused (NULL)
1389  * @param key unused
1390  * @param entry entry of type "struct DownloadRequest" which is freed
1391  * @return GNUNET_OK
1392  */
1393 static int
1394 free_entry (void *cls,
1395             const GNUNET_HashCode *key,
1396             void *entry)
1397 {
1398   GNUNET_free (entry);
1399   return GNUNET_OK;
1400 }
1401
1402
1403 /**
1404  * Stop a download (aborts if download is incomplete).
1405  *
1406  * @param dc handle for the download
1407  * @param do_delete delete files of incomplete downloads
1408  */
1409 void
1410 GNUNET_FS_download_stop (struct GNUNET_FS_DownloadContext *dc,
1411                          int do_delete)
1412 {
1413   struct GNUNET_FS_ProgressInfo pi;
1414
1415   while (NULL != dc->child_head)
1416     GNUNET_FS_download_stop (dc->child_head,
1417                              do_delete);
1418   // FIXME: make unpersistent
1419   if (dc->parent != NULL)
1420     GNUNET_CONTAINER_DLL_remove (dc->parent->child_head,
1421                                  dc->parent->child_tail,
1422                                  dc);
1423
1424   pi.status = GNUNET_FS_STATUS_DOWNLOAD_STOPPED;
1425   make_download_status (&pi, dc);
1426   dc->client_info = dc->h->upcb (dc->h->upcb_cls,
1427                                  &pi);
1428
1429   if (GNUNET_SCHEDULER_NO_TASK != dc->task)
1430     GNUNET_SCHEDULER_cancel (dc->h->sched,
1431                              dc->task);
1432   if (NULL != dc->th)
1433     {
1434       GNUNET_CLIENT_notify_transmit_ready_cancel (dc->th);
1435       dc->th = NULL;
1436     }
1437   if (NULL != dc->client)
1438     GNUNET_CLIENT_disconnect (dc->client, GNUNET_NO);
1439   GNUNET_CONTAINER_multihashmap_iterate (dc->active,
1440                                          &free_entry,
1441                                          NULL);
1442   GNUNET_CONTAINER_multihashmap_destroy (dc->active);
1443   if (dc->filename != NULL)
1444     {
1445       if (NULL != dc->handle)
1446         GNUNET_DISK_file_close (dc->handle);
1447       if ( (dc->completed != dc->length) &&
1448            (GNUNET_YES == do_delete) )
1449         {
1450           if (0 != UNLINK (dc->filename))
1451             GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
1452                                       "unlink",
1453                                       dc->filename);
1454         }
1455       GNUNET_free (dc->filename);
1456     }
1457   GNUNET_CONTAINER_meta_data_destroy (dc->meta);
1458   GNUNET_FS_uri_destroy (dc->uri);
1459   GNUNET_free (dc);
1460 }
1461
1462 /* end of fs_download.c */