http-fetch.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "pack.h"
   4 #include "fetch.h"
   5 #include "http.h"
   6
   7 #define PREV_BUF_SIZE 4096
   8 #define RANGE_HEADER_SIZE 30
   9
  10 static int got_alternates = -1;
  11
  12 static struct curl_slist *no_pragma_header;
  13
  14 struct alt_base
  15 {
  16         char *base;
  17         int got_indices;
  18         struct packed_git *packs;
  19         struct alt_base *next;
  20 };
  21
  22 static struct alt_base *alt = NULL;
  23
  24 enum object_request_state {
  25         WAITING,
  26         ABORTED,
  27         ACTIVE,
  28         COMPLETE,
  29 };
  30
  31 struct object_request
  32 {
  33         unsigned char sha1[20];
  34         struct alt_base *repo;
  35         char *url;
  36         char filename[PATH_MAX];
  37         char tmpfile[PATH_MAX];
  38         int local;
  39         enum object_request_state state;
  40         CURLcode curl_result;
  41         char errorstr[CURL_ERROR_SIZE];
  42         long http_code;
  43         unsigned char real_sha1[20];
  44         SHA_CTX c;
  45         z_stream stream;
  46         int zret;
  47         int rename;
  48         struct active_request_slot *slot;
  49         struct object_request *next;
  50 };
  51
  52 struct alternates_request {
  53         char *base;
  54         char *url;
  55         struct buffer *buffer;
  56         struct active_request_slot *slot;
  57         int http_specific;
  58 };
  59
  60 static struct object_request *object_queue_head = NULL;
  61
  62 static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
  63                                void *data)
  64 {
  65         unsigned char expn[4096];
  66         size_t size = eltsize * nmemb;
  67         int posn = 0;
  68         struct object_request *obj_req = (struct object_request *)data;
  69         do {
  70                 ssize_t retval = write(obj_req->local,
  71                                        ptr + posn, size - posn);
  72                 if (retval < 0)
  73                         return posn;
  74                 posn += retval;
  75         } while (posn < size);
  76
  77         obj_req->stream.avail_in = size;
  78         obj_req->stream.next_in = ptr;
  79         do {
  80                 obj_req->stream.next_out = expn;
  81                 obj_req->stream.avail_out = sizeof(expn);
  82                 obj_req->zret = inflate(&obj_req->stream, Z_SYNC_FLUSH);
  83                 SHA1_Update(&obj_req->c, expn,
  84                             sizeof(expn) - obj_req->stream.avail_out);
  85         } while (obj_req->stream.avail_in && obj_req->zret == Z_OK);
  86         data_received++;
  87         return size;
  88 }
  89
  90 static void fetch_alternates(char *base);
  91
  92 static void process_object_response(void *callback_data);
  93
  94 static void start_object_request(struct object_request *obj_req)
  95 {
  96         char *hex = sha1_to_hex(obj_req->sha1);
  97         char prevfile[PATH_MAX];
  98         char *url;
  99         char *posn;
 100         int prevlocal;
 101         unsigned char prev_buf[PREV_BUF_SIZE];
 102         ssize_t prev_read = 0;
 103         long prev_posn = 0;
 104         char range[RANGE_HEADER_SIZE];
 105         struct curl_slist *range_header = NULL;
 106         struct active_request_slot *slot;
 107
 108         snprintf(prevfile, sizeof(prevfile), "%s.prev", obj_req->filename);
 109         unlink(prevfile);
 110         rename(obj_req->tmpfile, prevfile);
 111         unlink(obj_req->tmpfile);
 112
 113         if (obj_req->local != -1)
 114                 error("fd leakage in start: %d", obj_req->local);
 115         obj_req->local = open(obj_req->tmpfile,
 116                               O_WRONLY | O_CREAT | O_EXCL, 0666);
 117         /* This could have failed due to the "lazy directory creation";
 118          * try to mkdir the last path component.
 119          */
 120         if (obj_req->local < 0 && errno == ENOENT) {
 121                 char *dir = strrchr(obj_req->tmpfile, '/');
 122                 if (dir) {
 123                         *dir = 0;
 124                         mkdir(obj_req->tmpfile, 0777);
 125                         *dir = '/';
 126                 }
 127                 obj_req->local = open(obj_req->tmpfile,
 128                                       O_WRONLY | O_CREAT | O_EXCL, 0666);
 129         }
 130
 131         if (obj_req->local < 0) {
 132                 obj_req->state = ABORTED;
 133                 error("Couldn't create temporary file %s for %s: %s\n",
 134                       obj_req->tmpfile, obj_req->filename, strerror(errno));
 135                 return;
 136         }
 137
 138         memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 139
 140         inflateInit(&obj_req->stream);
 141
 142         SHA1_Init(&obj_req->c);
 143
 144         url = xmalloc(strlen(obj_req->repo->base) + 50);
 145         obj_req->url = xmalloc(strlen(obj_req->repo->base) + 50);
 146         strcpy(url, obj_req->repo->base);
 147         posn = url + strlen(obj_req->repo->base);
 148         strcpy(posn, "objects/");
 149         posn += 8;
 150         memcpy(posn, hex, 2);
 151         posn += 2;
 152         *(posn++) = '/';
 153         strcpy(posn, hex + 2);
 154         strcpy(obj_req->url, url);
 155
 156         /* If a previous temp file is present, process what was already
 157            fetched. */
 158         prevlocal = open(prevfile, O_RDONLY);
 159         if (prevlocal != -1) {
 160                 do {
 161                         prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 162                         if (prev_read>0) {
 163                                 if (fwrite_sha1_file(prev_buf,
 164                                                      1,
 165                                                      prev_read,
 166                                                      obj_req) == prev_read) {
 167                                         prev_posn += prev_read;
 168                                 } else {
 169                                         prev_read = -1;
 170                                 }
 171                         }
 172                 } while (prev_read > 0);
 173                 close(prevlocal);
 174         }
 175         unlink(prevfile);
 176
 177         /* Reset inflate/SHA1 if there was an error reading the previous temp
 178            file; also rewind to the beginning of the local file. */
 179         if (prev_read == -1) {
 180                 memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 181                 inflateInit(&obj_req->stream);
 182                 SHA1_Init(&obj_req->c);
 183                 if (prev_posn>0) {
 184                         prev_posn = 0;
 185                         lseek(obj_req->local, SEEK_SET, 0);
 186                         ftruncate(obj_req->local, 0);
 187                 }
 188         }
 189
 190         slot = get_active_slot();
 191         slot->callback_func = process_object_response;
 192         slot->callback_data = obj_req;
 193         obj_req->slot = slot;
 194
 195         curl_easy_setopt(slot->curl, CURLOPT_FILE, obj_req);
 196         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 197         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, obj_req->errorstr);
 198         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 199         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 200
 201         /* If we have successfully processed data from a previous fetch
 202            attempt, only fetch the data we don't already have. */
 203         if (prev_posn>0) {
 204                 if (get_verbosely)
 205                         fprintf(stderr,
 206                                 "Resuming fetch of object %s at byte %ld\n",
 207                                 hex, prev_posn);
 208                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 209                 range_header = curl_slist_append(range_header, range);
 210                 curl_easy_setopt(slot->curl,
 211                                  CURLOPT_HTTPHEADER, range_header);
 212         }
 213
 214         /* Try to get the request started, abort the request on error */
 215         obj_req->state = ACTIVE;
 216         if (!start_active_slot(slot)) {
 217                 obj_req->state = ABORTED;
 218                 obj_req->slot = NULL;
 219                 close(obj_req->local); obj_req->local = -1;
 220                 free(obj_req->url);
 221                 return;
 222         }
 223
 224 }
 225
 226 static void finish_object_request(struct object_request *obj_req)
 227 {
 228         struct stat st;
 229
 230         fchmod(obj_req->local, 0444);
 231         close(obj_req->local); obj_req->local = -1;
 232
 233         if (obj_req->http_code == 416) {
 234                 fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 235         } else if (obj_req->curl_result != CURLE_OK) {
 236                 if (stat(obj_req->tmpfile, &st) == 0)
 237                         if (st.st_size == 0)
 238                                 unlink(obj_req->tmpfile);
 239                 return;
 240         }
 241
 242         inflateEnd(&obj_req->stream);
 243         SHA1_Final(obj_req->real_sha1, &obj_req->c);
 244         if (obj_req->zret != Z_STREAM_END) {
 245                 unlink(obj_req->tmpfile);
 246                 return;
 247         }
 248         if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 249                 unlink(obj_req->tmpfile);
 250                 return;
 251         }
 252         obj_req->rename =
 253                 move_temp_to_file(obj_req->tmpfile, obj_req->filename);
 254
 255         if (obj_req->rename == 0)
 256                 pull_say("got %s\n", sha1_to_hex(obj_req->sha1));
 257 }
 258
 259 static void process_object_response(void *callback_data)
 260 {
 261         struct object_request *obj_req =
 262                 (struct object_request *)callback_data;
 263
 264         obj_req->curl_result = obj_req->slot->curl_result;
 265         obj_req->http_code = obj_req->slot->http_code;
 266         obj_req->slot = NULL;
 267         obj_req->state = COMPLETE;
 268
 269         /* Use alternates if necessary */
 270         if (obj_req->http_code == 404 ||
 271             obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 272                 fetch_alternates(alt->base);
 273                 if (obj_req->repo->next != NULL) {
 274                         obj_req->repo =
 275                                 obj_req->repo->next;
 276                         close(obj_req->local);
 277                         obj_req->local = -1;
 278                         start_object_request(obj_req);
 279                         return;
 280                 }
 281         }
 282
 283         finish_object_request(obj_req);
 284 }
 285
 286 static void release_object_request(struct object_request *obj_req)
 287 {
 288         struct object_request *entry = object_queue_head;
 289
 290         if (obj_req->local != -1)
 291                 error("fd leakage in release: %d", obj_req->local);
 292         if (obj_req == object_queue_head) {
 293                 object_queue_head = obj_req->next;
 294         } else {
 295                 while (entry->next != NULL && entry->next != obj_req)
 296                         entry = entry->next;
 297                 if (entry->next == obj_req)
 298                         entry->next = entry->next->next;
 299         }
 300
 301         free(obj_req->url);
 302         free(obj_req);
 303 }
 304
 305 #ifdef USE_CURL_MULTI
 306 void fill_active_slots(void)
 307 {
 308         struct object_request *obj_req = object_queue_head;
 309         struct active_request_slot *slot = active_queue_head;
 310         int num_transfers;
 311
 312         while (active_requests < max_requests && obj_req != NULL) {
 313                 if (obj_req->state == WAITING) {
 314                         if (has_sha1_file(obj_req->sha1))
 315                                 release_object_request(obj_req);
 316                         else
 317                                 start_object_request(obj_req);
 318                         curl_multi_perform(curlm, &num_transfers);
 319                 }
 320                 obj_req = obj_req->next;
 321         }
 322
 323         while (slot != NULL) {
 324                 if (!slot->in_use && slot->curl != NULL) {
 325                         curl_easy_cleanup(slot->curl);
 326                         slot->curl = NULL;
 327                 }
 328                 slot = slot->next;
 329         }
 330 }
 331 #endif
 332
 333 void prefetch(unsigned char *sha1)
 334 {
 335         struct object_request *newreq;
 336         struct object_request *tail;
 337         char *filename = sha1_file_name(sha1);
 338
 339         newreq = xmalloc(sizeof(*newreq));
 340         memcpy(newreq->sha1, sha1, 20);
 341         newreq->repo = alt;
 342         newreq->url = NULL;
 343         newreq->local = -1;
 344         newreq->state = WAITING;
 345         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 346         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 347                  "%s.temp", filename);
 348         newreq->next = NULL;
 349
 350         if (object_queue_head == NULL) {
 351                 object_queue_head = newreq;
 352         } else {
 353                 tail = object_queue_head;
 354                 while (tail->next != NULL) {
 355                         tail = tail->next;
 356                 }
 357                 tail->next = newreq;
 358         }
 359
 360 #ifdef USE_CURL_MULTI
 361         fill_active_slots();
 362         step_active_slots();
 363 #endif
 364 }
 365
 366 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 367 {
 368         char *hex = sha1_to_hex(sha1);
 369         char *filename;
 370         char *url;
 371         char tmpfile[PATH_MAX];
 372         long prev_posn = 0;
 373         char range[RANGE_HEADER_SIZE];
 374         struct curl_slist *range_header = NULL;
 375
 376         FILE *indexfile;
 377         struct active_request_slot *slot;
 378         static struct slot_results results;
 379
 380         if (has_pack_index(sha1))
 381                 return 0;
 382
 383         if (get_verbosely)
 384                 fprintf(stderr, "Getting index for pack %s\n", hex);
 385
 386         url = xmalloc(strlen(repo->base) + 64);
 387         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 388
 389         filename = sha1_pack_index_name(sha1);
 390         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 391         indexfile = fopen(tmpfile, "a");
 392         if (!indexfile)
 393                 return error("Unable to open local file %s for pack index",
 394                              filename);
 395
 396         slot = get_active_slot();
 397         slot->results = &results;
 398         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 399         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 400         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 401         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 402         slot->local = indexfile;
 403
 404         /* If there is data present from a previous transfer attempt,
 405            resume where it left off */
 406         prev_posn = ftell(indexfile);
 407         if (prev_posn>0) {
 408                 if (get_verbosely)
 409                         fprintf(stderr,
 410                                 "Resuming fetch of index for pack %s at byte %ld\n",
 411                                 hex, prev_posn);
 412                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 413                 range_header = curl_slist_append(range_header, range);
 414                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 415         }
 416
 417         if (start_active_slot(slot)) {
 418                 run_active_slot(slot);
 419                 if (results.curl_result != CURLE_OK) {
 420                         fclose(indexfile);
 421                         return error("Unable to get pack index %s\n%s", url,
 422                                      curl_errorstr);
 423                 }
 424         } else {
 425                 fclose(indexfile);
 426                 return error("Unable to start request");
 427         }
 428
 429         fclose(indexfile);
 430
 431         return move_temp_to_file(tmpfile, filename);
 432 }
 433
 434 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 435 {
 436         struct packed_git *new_pack;
 437         if (has_pack_file(sha1))
 438                 return 0; // don't list this as something we can get
 439
 440         if (fetch_index(repo, sha1))
 441                 return -1;
 442
 443         new_pack = parse_pack_index(sha1);
 444         new_pack->next = repo->packs;
 445         repo->packs = new_pack;
 446         return 0;
 447 }
 448
 449 static void process_alternates_response(void *callback_data)
 450 {
 451         struct alternates_request *alt_req =
 452                 (struct alternates_request *)callback_data;
 453         struct active_request_slot *slot = alt_req->slot;
 454         struct alt_base *tail = alt;
 455         char *base = alt_req->base;
 456         static const char null_byte = '\0';
 457         char *data;
 458         int i = 0;
 459
 460         if (alt_req->http_specific) {
 461                 if (slot->curl_result != CURLE_OK ||
 462                     !alt_req->buffer->posn) {
 463
 464                         /* Try reusing the slot to get non-http alternates */
 465                         alt_req->http_specific = 0;
 466                         sprintf(alt_req->url, "%s/objects/info/alternates",
 467                                 base);
 468                         curl_easy_setopt(slot->curl, CURLOPT_URL,
 469                                          alt_req->url);
 470                         active_requests++;
 471                         slot->in_use = 1;
 472                         if (start_active_slot(slot)) {
 473                                 return;
 474                         } else {
 475                                 got_alternates = -1;
 476                                 slot->in_use = 0;
 477                                 return;
 478                         }
 479                 }
 480         } else if (slot->curl_result != CURLE_OK) {
 481                 if (slot->http_code != 404 &&
 482                     slot->curl_result != CURLE_FILE_COULDNT_READ_FILE) {
 483                         got_alternates = -1;
 484                         return;
 485                 }
 486         }
 487
 488         fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 489         alt_req->buffer->posn--;
 490         data = alt_req->buffer->buffer;
 491
 492         while (i < alt_req->buffer->posn) {
 493                 int posn = i;
 494                 while (posn < alt_req->buffer->posn && data[posn] != '\n')
 495                         posn++;
 496                 if (data[posn] == '\n') {
 497                         int okay = 0;
 498                         int serverlen = 0;
 499                         struct alt_base *newalt;
 500                         char *target = NULL;
 501                         if (data[i] == '/') {
 502                                 serverlen = strchr(base + 8, '/') - base;
 503                                 okay = 1;
 504                         } else if (!memcmp(data + i, "../", 3)) {
 505                                 i += 3;
 506                                 serverlen = strlen(base);
 507                                 while (i + 2 < posn &&
 508                                        !memcmp(data + i, "../", 3)) {
 509                                         do {
 510                                                 serverlen--;
 511                                         } while (serverlen &&
 512                                                  base[serverlen - 1] != '/');
 513                                         i += 3;
 514                                 }
 515                                 // If the server got removed, give up.
 516                                 okay = strchr(base, ':') - base + 3 <
 517                                         serverlen;
 518                         } else if (alt_req->http_specific) {
 519                                 char *colon = strchr(data + i, ':');
 520                                 char *slash = strchr(data + i, '/');
 521                                 if (colon && slash && colon < data + posn &&
 522                                     slash < data + posn && colon < slash) {
 523                                         okay = 1;
 524                                 }
 525                         }
 526                         // skip 'objects' at end
 527                         if (okay) {
 528                                 target = xmalloc(serverlen + posn - i - 6);
 529                                 strncpy(target, base, serverlen);
 530                                 strncpy(target + serverlen, data + i,
 531                                         posn - i - 7);
 532                                 target[serverlen + posn - i - 7] = '\0';
 533                                 if (get_verbosely)
 534                                         fprintf(stderr,
 535                                                 "Also look at %s\n", target);
 536                                 newalt = xmalloc(sizeof(*newalt));
 537                                 newalt->next = NULL;
 538                                 newalt->base = target;
 539                                 newalt->got_indices = 0;
 540                                 newalt->packs = NULL;
 541                                 while (tail->next != NULL)
 542                                         tail = tail->next;
 543                                 tail->next = newalt;
 544                         }
 545                 }
 546                 i = posn + 1;
 547         }
 548
 549         got_alternates = 1;
 550 }
 551
 552 static void fetch_alternates(char *base)
 553 {
 554         struct buffer buffer;
 555         char *url;
 556         char *data;
 557         struct active_request_slot *slot;
 558         static struct alternates_request alt_req;
 559
 560         /* If another request has already started fetching alternates,
 561            wait for them to arrive and return to processing this request's
 562            curl message */
 563 #ifdef USE_CURL_MULTI
 564         while (got_alternates == 0) {
 565                 step_active_slots();
 566         }
 567 #endif
 568
 569         /* Nothing to do if they've already been fetched */
 570         if (got_alternates == 1)
 571                 return;
 572
 573         /* Start the fetch */
 574         got_alternates = 0;
 575
 576         data = xmalloc(4096);
 577         buffer.size = 4096;
 578         buffer.posn = 0;
 579         buffer.buffer = data;
 580
 581         if (get_verbosely)
 582                 fprintf(stderr, "Getting alternates list for %s\n", base);
 583
 584         url = xmalloc(strlen(base) + 31);
 585         sprintf(url, "%s/objects/info/http-alternates", base);
 586
 587         /* Use a callback to process the result, since another request
 588            may fail and need to have alternates loaded before continuing */
 589         slot = get_active_slot();
 590         slot->callback_func = process_alternates_response;
 591         slot->callback_data = &alt_req;
 592
 593         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 594         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 595         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 596
 597         alt_req.base = base;
 598         alt_req.url = url;
 599         alt_req.buffer = &buffer;
 600         alt_req.http_specific = 1;
 601         alt_req.slot = slot;
 602
 603         if (start_active_slot(slot))
 604                 run_active_slot(slot);
 605         else
 606                 got_alternates = -1;
 607
 608         free(data);
 609         free(url);
 610 }
 611
 612 static int fetch_indices(struct alt_base *repo)
 613 {
 614         unsigned char sha1[20];
 615         char *url;
 616         struct buffer buffer;
 617         char *data;
 618         int i = 0;
 619
 620         struct active_request_slot *slot;
 621         static struct slot_results results;
 622
 623         if (repo->got_indices)
 624                 return 0;
 625
 626         data = xmalloc(4096);
 627         buffer.size = 4096;
 628         buffer.posn = 0;
 629         buffer.buffer = data;
 630
 631         if (get_verbosely)
 632                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
 633
 634         url = xmalloc(strlen(repo->base) + 21);
 635         sprintf(url, "%s/objects/info/packs", repo->base);
 636
 637         slot = get_active_slot();
 638         slot->results = &results;
 639         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 640         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 641         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 642         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 643         if (start_active_slot(slot)) {
 644                 run_active_slot(slot);
 645                 if (results.curl_result != CURLE_OK) {
 646                         if (results.http_code == 404 ||
 647                             results.curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 648                                 repo->got_indices = 1;
 649                                 free(buffer.buffer);
 650                                 return 0;
 651                         } else {
 652                                 repo->got_indices = 0;
 653                                 free(buffer.buffer);
 654                                 return error("%s", curl_errorstr);
 655                         }
 656                 }
 657         } else {
 658                 repo->got_indices = 0;
 659                 free(buffer.buffer);
 660                 return error("Unable to start request");
 661         }
 662
 663         data = buffer.buffer;
 664         while (i < buffer.posn) {
 665                 switch (data[i]) {
 666                 case 'P':
 667                         i++;
 668                         if (i + 52 <= buffer.posn &&
 669                             !strncmp(data + i, " pack-", 6) &&
 670                             !strncmp(data + i + 46, ".pack\n", 6)) {
 671                                 get_sha1_hex(data + i + 6, sha1);
 672                                 setup_index(repo, sha1);
 673                                 i += 51;
 674                                 break;
 675                         }
 676                 default:
 677                         while (i < buffer.posn && data[i] != '\n')
 678                                 i++;
 679                 }
 680                 i++;
 681         }
 682
 683         free(buffer.buffer);
 684         repo->got_indices = 1;
 685         return 0;
 686 }
 687
 688 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 689 {
 690         char *url;
 691         struct packed_git *target;
 692         struct packed_git **lst;
 693         FILE *packfile;
 694         char *filename;
 695         char tmpfile[PATH_MAX];
 696         int ret;
 697         long prev_posn = 0;
 698         char range[RANGE_HEADER_SIZE];
 699         struct curl_slist *range_header = NULL;
 700
 701         struct active_request_slot *slot;
 702         static struct slot_results results;
 703
 704         if (fetch_indices(repo))
 705                 return -1;
 706         target = find_sha1_pack(sha1, repo->packs);
 707         if (!target)
 708                 return -1;
 709
 710         if (get_verbosely) {
 711                 fprintf(stderr, "Getting pack %s\n",
 712                         sha1_to_hex(target->sha1));
 713                 fprintf(stderr, " which contains %s\n",
 714                         sha1_to_hex(sha1));
 715         }
 716
 717         url = xmalloc(strlen(repo->base) + 65);
 718         sprintf(url, "%s/objects/pack/pack-%s.pack",
 719                 repo->base, sha1_to_hex(target->sha1));
 720
 721         filename = sha1_pack_name(target->sha1);
 722         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 723         packfile = fopen(tmpfile, "a");
 724         if (!packfile)
 725                 return error("Unable to open local file %s for pack",
 726                              filename);
 727
 728         slot = get_active_slot();
 729         slot->results = &results;
 730         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 731         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 732         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 733         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 734         slot->local = packfile;
 735
 736         /* If there is data present from a previous transfer attempt,
 737            resume where it left off */
 738         prev_posn = ftell(packfile);
 739         if (prev_posn>0) {
 740                 if (get_verbosely)
 741                         fprintf(stderr,
 742                                 "Resuming fetch of pack %s at byte %ld\n",
 743                                 sha1_to_hex(target->sha1), prev_posn);
 744                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 745                 range_header = curl_slist_append(range_header, range);
 746                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 747         }
 748
 749         if (start_active_slot(slot)) {
 750                 run_active_slot(slot);
 751                 if (results.curl_result != CURLE_OK) {
 752                         fclose(packfile);
 753                         return error("Unable to get pack file %s\n%s", url,
 754                                      curl_errorstr);
 755                 }
 756         } else {
 757                 fclose(packfile);
 758                 return error("Unable to start request");
 759         }
 760
 761         fclose(packfile);
 762
 763         ret = move_temp_to_file(tmpfile, filename);
 764         if (ret)
 765                 return ret;
 766
 767         lst = &repo->packs;
 768         while (*lst != target)
 769                 lst = &((*lst)->next);
 770         *lst = (*lst)->next;
 771
 772         if (verify_pack(target, 0))
 773                 return -1;
 774         install_packed_git(target);
 775
 776         return 0;
 777 }
 778
 779 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 780 {
 781         char *hex = sha1_to_hex(sha1);
 782         int ret = 0;
 783         struct object_request *obj_req = object_queue_head;
 784
 785         while (obj_req != NULL && memcmp(obj_req->sha1, sha1, 20))
 786                 obj_req = obj_req->next;
 787         if (obj_req == NULL)
 788                 return error("Couldn't find request for %s in the queue", hex);
 789
 790         if (has_sha1_file(obj_req->sha1)) {
 791                 release_object_request(obj_req);
 792                 return 0;
 793         }
 794
 795 #ifdef USE_CURL_MULTI
 796         while (obj_req->state == WAITING) {
 797                 step_active_slots();
 798         }
 799 #else
 800         start_object_request(obj_req);
 801 #endif
 802
 803         while (obj_req->state == ACTIVE) {
 804                 run_active_slot(obj_req->slot);
 805         }
 806         if (obj_req->local != -1) {
 807                 close(obj_req->local); obj_req->local = -1;
 808         }
 809
 810         if (obj_req->state == ABORTED) {
 811                 ret = error("Request for %s aborted", hex);
 812         } else if (obj_req->curl_result != CURLE_OK &&
 813                    obj_req->http_code != 416) {
 814                 if (obj_req->http_code == 404 ||
 815                     obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE)
 816                         ret = -1; /* Be silent, it is probably in a pack. */
 817                 else
 818                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 819                                     obj_req->errorstr, obj_req->curl_result,
 820                                     obj_req->http_code, hex);
 821         } else if (obj_req->zret != Z_STREAM_END) {
 822                 ret = error("File %s (%s) corrupt\n", hex, obj_req->url);
 823         } else if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 824                 ret = error("File %s has bad hash\n", hex);
 825         } else if (obj_req->rename < 0) {
 826                 ret = error("unable to write sha1 filename %s: %s",
 827                             obj_req->filename,
 828                             strerror(obj_req->rename));
 829         }
 830
 831         release_object_request(obj_req);
 832         return ret;
 833 }
 834
 835 int fetch(unsigned char *sha1)
 836 {
 837         struct alt_base *altbase = alt;
 838
 839         if (!fetch_object(altbase, sha1))
 840                 return 0;
 841         while (altbase) {
 842                 if (!fetch_pack(altbase, sha1))
 843                         return 0;
 844                 fetch_alternates(alt->base);
 845                 altbase = altbase->next;
 846         }
 847         return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
 848                      alt->base);
 849 }
 850
 851 static inline int needs_quote(int ch)
 852 {
 853         switch (ch) {
 854         case '/': case '-': case '.':
 855         case 'A'...'Z': case 'a'...'z': case '0'...'9':
 856                 return 0;
 857         default:
 858                 return 1;
 859         }
 860 }
 861
 862 static inline int hex(int v)
 863 {
 864         if (v < 10) return '0' + v;
 865         else return 'A' + v - 10;
 866 }
 867
 868 static char *quote_ref_url(const char *base, const char *ref)
 869 {
 870         const char *cp;
 871         char *dp, *qref;
 872         int len, baselen, ch;
 873
 874         baselen = strlen(base);
 875         len = baselen + 6; /* "refs/" + NUL */
 876         for (cp = ref; (ch = *cp) != 0; cp++, len++)
 877                 if (needs_quote(ch))
 878                         len += 2; /* extra two hex plus replacement % */
 879         qref = xmalloc(len);
 880         memcpy(qref, base, baselen);
 881         memcpy(qref + baselen, "refs/", 5);
 882         for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
 883                 if (needs_quote(ch)) {
 884                         *dp++ = '%';
 885                         *dp++ = hex((ch >> 4) & 0xF);
 886                         *dp++ = hex(ch & 0xF);
 887                 }
 888                 else
 889                         *dp++ = ch;
 890         }
 891         *dp = 0;
 892
 893         return qref;
 894 }
 895
 896 int fetch_ref(char *ref, unsigned char *sha1)
 897 {
 898         char *url;
 899         char hex[42];
 900         struct buffer buffer;
 901         char *base = alt->base;
 902         struct active_request_slot *slot;
 903         static struct slot_results results;
 904         buffer.size = 41;
 905         buffer.posn = 0;
 906         buffer.buffer = hex;
 907         hex[41] = '\0';
 908
 909         url = quote_ref_url(base, ref);
 910         slot = get_active_slot();
 911         slot->results = &results;
 912         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 913         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 914         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 915         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 916         if (start_active_slot(slot)) {
 917                 run_active_slot(slot);
 918                 if (results.curl_result != CURLE_OK)
 919                         return error("Couldn't get %s for %s\n%s",
 920                                      url, ref, curl_errorstr);
 921         } else {
 922                 return error("Unable to start request");
 923         }
 924
 925         hex[40] = '\0';
 926         get_sha1_hex(hex, sha1);
 927         return 0;
 928 }
 929
 930 int main(int argc, char **argv)
 931 {
 932         char *commit_id;
 933         char *url;
 934         int arg = 1;
 935         int rc = 0;
 936
 937         setup_git_directory();
 938
 939         while (arg < argc && argv[arg][0] == '-') {
 940                 if (argv[arg][1] == 't') {
 941                         get_tree = 1;
 942                 } else if (argv[arg][1] == 'c') {
 943                         get_history = 1;
 944                 } else if (argv[arg][1] == 'a') {
 945                         get_all = 1;
 946                         get_tree = 1;
 947                         get_history = 1;
 948                 } else if (argv[arg][1] == 'v') {
 949                         get_verbosely = 1;
 950                 } else if (argv[arg][1] == 'w') {
 951                         write_ref = argv[arg + 1];
 952                         arg++;
 953                 } else if (!strcmp(argv[arg], "--recover")) {
 954                         get_recover = 1;
 955                 }
 956                 arg++;
 957         }
 958         if (argc < arg + 2) {
 959                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
 960                 return 1;
 961         }
 962         commit_id = argv[arg];
 963         url = argv[arg + 1];
 964
 965         http_init();
 966
 967         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 968
 969         alt = xmalloc(sizeof(*alt));
 970         alt->base = url;
 971         alt->got_indices = 0;
 972         alt->packs = NULL;
 973         alt->next = NULL;
 974
 975         if (pull(commit_id))
 976                 rc = 1;
 977
 978         curl_slist_free_all(no_pragma_header);
 979
 980         http_cleanup();
 981
 982         return rc;
 983 }