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                 fetch_alternates(alt->base);
 272                 if (obj_req->repo->next != NULL) {
 273                         obj_req->repo =
 274                                 obj_req->repo->next;
 275                         close(obj_req->local);
 276                         obj_req->local = -1;
 277                         start_object_request(obj_req);
 278                         return;
 279                 }
 280         }
 281
 282         finish_object_request(obj_req);
 283 }
 284
 285 static void release_object_request(struct object_request *obj_req)
 286 {
 287         struct object_request *entry = object_queue_head;
 288
 289         if (obj_req->local != -1)
 290                 error("fd leakage in release: %d", obj_req->local);
 291         if (obj_req == object_queue_head) {
 292                 object_queue_head = obj_req->next;
 293         } else {
 294                 while (entry->next != NULL && entry->next != obj_req)
 295                         entry = entry->next;
 296                 if (entry->next == obj_req)
 297                         entry->next = entry->next->next;
 298         }
 299
 300         free(obj_req->url);
 301         free(obj_req);
 302 }
 303
 304 #ifdef USE_CURL_MULTI
 305 void fill_active_slots(void)
 306 {
 307         struct object_request *obj_req = object_queue_head;
 308         struct active_request_slot *slot = active_queue_head;
 309         int num_transfers;
 310
 311         while (active_requests < max_requests && obj_req != NULL) {
 312                 if (obj_req->state == WAITING) {
 313                         if (has_sha1_file(obj_req->sha1))
 314                                 release_object_request(obj_req);
 315                         else
 316                                 start_object_request(obj_req);
 317                         curl_multi_perform(curlm, &num_transfers);
 318                 }
 319                 obj_req = obj_req->next;
 320         }
 321
 322         while (slot != NULL) {
 323                 if (!slot->in_use && slot->curl != NULL) {
 324                         curl_easy_cleanup(slot->curl);
 325                         slot->curl = NULL;
 326                 }
 327                 slot = slot->next;
 328         }
 329 }
 330 #endif
 331
 332 void prefetch(unsigned char *sha1)
 333 {
 334         struct object_request *newreq;
 335         struct object_request *tail;
 336         char *filename = sha1_file_name(sha1);
 337
 338         newreq = xmalloc(sizeof(*newreq));
 339         memcpy(newreq->sha1, sha1, 20);
 340         newreq->repo = alt;
 341         newreq->url = NULL;
 342         newreq->local = -1;
 343         newreq->state = WAITING;
 344         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 345         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 346                  "%s.temp", filename);
 347         newreq->next = NULL;
 348
 349         if (object_queue_head == NULL) {
 350                 object_queue_head = newreq;
 351         } else {
 352                 tail = object_queue_head;
 353                 while (tail->next != NULL) {
 354                         tail = tail->next;
 355                 }
 356                 tail->next = newreq;
 357         }
 358
 359 #ifdef USE_CURL_MULTI
 360         fill_active_slots();
 361         step_active_slots();
 362 #endif
 363 }
 364
 365 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 366 {
 367         char *hex = sha1_to_hex(sha1);
 368         char *filename;
 369         char *url;
 370         char tmpfile[PATH_MAX];
 371         long prev_posn = 0;
 372         char range[RANGE_HEADER_SIZE];
 373         struct curl_slist *range_header = NULL;
 374
 375         FILE *indexfile;
 376         struct active_request_slot *slot;
 377
 378         if (has_pack_index(sha1))
 379                 return 0;
 380
 381         if (get_verbosely)
 382                 fprintf(stderr, "Getting index for pack %s\n", hex);
 383
 384         url = xmalloc(strlen(repo->base) + 64);
 385         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 386
 387         filename = sha1_pack_index_name(sha1);
 388         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 389         indexfile = fopen(tmpfile, "a");
 390         if (!indexfile)
 391                 return error("Unable to open local file %s for pack index",
 392                              filename);
 393
 394         slot = get_active_slot();
 395         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 396         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 397         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 398         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 399         slot->local = indexfile;
 400
 401         /* If there is data present from a previous transfer attempt,
 402            resume where it left off */
 403         prev_posn = ftell(indexfile);
 404         if (prev_posn>0) {
 405                 if (get_verbosely)
 406                         fprintf(stderr,
 407                                 "Resuming fetch of index for pack %s at byte %ld\n",
 408                                 hex, prev_posn);
 409                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 410                 range_header = curl_slist_append(range_header, range);
 411                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 412         }
 413
 414         if (start_active_slot(slot)) {
 415                 run_active_slot(slot);
 416                 if (slot->curl_result != CURLE_OK) {
 417                         fclose(indexfile);
 418                         return error("Unable to get pack index %s\n%s", url,
 419                                      curl_errorstr);
 420                 }
 421         } else {
 422                 fclose(indexfile);
 423                 return error("Unable to start request");
 424         }
 425
 426         fclose(indexfile);
 427
 428         return move_temp_to_file(tmpfile, filename);
 429 }
 430
 431 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 432 {
 433         struct packed_git *new_pack;
 434         if (has_pack_file(sha1))
 435                 return 0; // don't list this as something we can get
 436
 437         if (fetch_index(repo, sha1))
 438                 return -1;
 439
 440         new_pack = parse_pack_index(sha1);
 441         new_pack->next = repo->packs;
 442         repo->packs = new_pack;
 443         return 0;
 444 }
 445
 446 static void process_alternates_response(void *callback_data)
 447 {
 448         struct alternates_request *alt_req =
 449                 (struct alternates_request *)callback_data;
 450         struct active_request_slot *slot = alt_req->slot;
 451         struct alt_base *tail = alt;
 452         char *base = alt_req->base;
 453         static const char null_byte = '\0';
 454         char *data;
 455         int i = 0;
 456
 457         if (alt_req->http_specific) {
 458                 if (slot->curl_result != CURLE_OK ||
 459                     !alt_req->buffer->posn) {
 460
 461                         /* Try reusing the slot to get non-http alternates */
 462                         alt_req->http_specific = 0;
 463                         sprintf(alt_req->url, "%s/objects/info/alternates",
 464                                 base);
 465                         curl_easy_setopt(slot->curl, CURLOPT_URL,
 466                                          alt_req->url);
 467                         active_requests++;
 468                         slot->in_use = 1;
 469                         if (start_active_slot(slot)) {
 470                                 return;
 471                         } else {
 472                                 got_alternates = -1;
 473                                 slot->in_use = 0;
 474                                 return;
 475                         }
 476                 }
 477         } else if (slot->curl_result != CURLE_OK) {
 478                 if (slot->http_code != 404) {
 479                         got_alternates = -1;
 480                         return;
 481                 }
 482         }
 483
 484         fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 485         alt_req->buffer->posn--;
 486         data = alt_req->buffer->buffer;
 487
 488         while (i < alt_req->buffer->posn) {
 489                 int posn = i;
 490                 while (posn < alt_req->buffer->posn && data[posn] != '\n')
 491                         posn++;
 492                 if (data[posn] == '\n') {
 493                         int okay = 0;
 494                         int serverlen = 0;
 495                         struct alt_base *newalt;
 496                         char *target = NULL;
 497                         if (data[i] == '/') {
 498                                 serverlen = strchr(base + 8, '/') - base;
 499                                 okay = 1;
 500                         } else if (!memcmp(data + i, "../", 3)) {
 501                                 i += 3;
 502                                 serverlen = strlen(base);
 503                                 while (i + 2 < posn &&
 504                                        !memcmp(data + i, "../", 3)) {
 505                                         do {
 506                                                 serverlen--;
 507                                         } while (serverlen &&
 508                                                  base[serverlen - 1] != '/');
 509                                         i += 3;
 510                                 }
 511                                 // If the server got removed, give up.
 512                                 okay = strchr(base, ':') - base + 3 <
 513                                         serverlen;
 514                         } else if (alt_req->http_specific) {
 515                                 char *colon = strchr(data + i, ':');
 516                                 char *slash = strchr(data + i, '/');
 517                                 if (colon && slash && colon < data + posn &&
 518                                     slash < data + posn && colon < slash) {
 519                                         okay = 1;
 520                                 }
 521                         }
 522                         // skip 'objects' at end
 523                         if (okay) {
 524                                 target = xmalloc(serverlen + posn - i - 6);
 525                                 strncpy(target, base, serverlen);
 526                                 strncpy(target + serverlen, data + i,
 527                                         posn - i - 7);
 528                                 target[serverlen + posn - i - 7] = '\0';
 529                                 if (get_verbosely)
 530                                         fprintf(stderr,
 531                                                 "Also look at %s\n", target);
 532                                 newalt = xmalloc(sizeof(*newalt));
 533                                 newalt->next = NULL;
 534                                 newalt->base = target;
 535                                 newalt->got_indices = 0;
 536                                 newalt->packs = NULL;
 537                                 while (tail->next != NULL)
 538                                         tail = tail->next;
 539                                 tail->next = newalt;
 540                         }
 541                 }
 542                 i = posn + 1;
 543         }
 544
 545         got_alternates = 1;
 546 }
 547
 548 static void fetch_alternates(char *base)
 549 {
 550         struct buffer buffer;
 551         char *url;
 552         char *data;
 553         struct active_request_slot *slot;
 554         static struct alternates_request alt_req;
 555
 556         /* If another request has already started fetching alternates,
 557            wait for them to arrive and return to processing this request's
 558            curl message */
 559 #ifdef USE_CURL_MULTI
 560         while (got_alternates == 0) {
 561                 step_active_slots();
 562         }
 563 #endif
 564
 565         /* Nothing to do if they've already been fetched */
 566         if (got_alternates == 1)
 567                 return;
 568
 569         /* Start the fetch */
 570         got_alternates = 0;
 571
 572         data = xmalloc(4096);
 573         buffer.size = 4096;
 574         buffer.posn = 0;
 575         buffer.buffer = data;
 576
 577         if (get_verbosely)
 578                 fprintf(stderr, "Getting alternates list for %s\n", base);
 579
 580         url = xmalloc(strlen(base) + 31);
 581         sprintf(url, "%s/objects/info/http-alternates", base);
 582
 583         /* Use a callback to process the result, since another request
 584            may fail and need to have alternates loaded before continuing */
 585         slot = get_active_slot();
 586         slot->callback_func = process_alternates_response;
 587         slot->callback_data = &alt_req;
 588
 589         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 590         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 591         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 592
 593         alt_req.base = base;
 594         alt_req.url = url;
 595         alt_req.buffer = &buffer;
 596         alt_req.http_specific = 1;
 597         alt_req.slot = slot;
 598
 599         if (start_active_slot(slot))
 600                 run_active_slot(slot);
 601         else
 602                 got_alternates = -1;
 603
 604         free(data);
 605         free(url);
 606 }
 607
 608 static int fetch_indices(struct alt_base *repo)
 609 {
 610         unsigned char sha1[20];
 611         char *url;
 612         struct buffer buffer;
 613         char *data;
 614         int i = 0;
 615
 616         struct active_request_slot *slot;
 617
 618         if (repo->got_indices)
 619                 return 0;
 620
 621         data = xmalloc(4096);
 622         buffer.size = 4096;
 623         buffer.posn = 0;
 624         buffer.buffer = data;
 625
 626         if (get_verbosely)
 627                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
 628
 629         url = xmalloc(strlen(repo->base) + 21);
 630         sprintf(url, "%s/objects/info/packs", repo->base);
 631
 632         slot = get_active_slot();
 633         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 634         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 635         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 636         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 637         if (start_active_slot(slot)) {
 638                 run_active_slot(slot);
 639                 if (slot->curl_result != CURLE_OK) {
 640                         if (slot->http_code == 404) {
 641                                 repo->got_indices = 1;
 642                                 free(buffer.buffer);
 643                                 return 0;
 644                         } else {
 645                                 repo->got_indices = 0;
 646                                 free(buffer.buffer);
 647                                 return error("%s", curl_errorstr);
 648                         }
 649                 }
 650         } else {
 651                 repo->got_indices = 0;
 652                 free(buffer.buffer);
 653                 return error("Unable to start request");
 654         }
 655
 656         data = buffer.buffer;
 657         while (i < buffer.posn) {
 658                 switch (data[i]) {
 659                 case 'P':
 660                         i++;
 661                         if (i + 52 < buffer.posn &&
 662                             !strncmp(data + i, " pack-", 6) &&
 663                             !strncmp(data + i + 46, ".pack\n", 6)) {
 664                                 get_sha1_hex(data + i + 6, sha1);
 665                                 setup_index(repo, sha1);
 666                                 i += 51;
 667                                 break;
 668                         }
 669                 default:
 670                         while (data[i] != '\n')
 671                                 i++;
 672                 }
 673                 i++;
 674         }
 675
 676         free(buffer.buffer);
 677         repo->got_indices = 1;
 678         return 0;
 679 }
 680
 681 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 682 {
 683         char *url;
 684         struct packed_git *target;
 685         struct packed_git **lst;
 686         FILE *packfile;
 687         char *filename;
 688         char tmpfile[PATH_MAX];
 689         int ret;
 690         long prev_posn = 0;
 691         char range[RANGE_HEADER_SIZE];
 692         struct curl_slist *range_header = NULL;
 693
 694         struct active_request_slot *slot;
 695
 696         if (fetch_indices(repo))
 697                 return -1;
 698         target = find_sha1_pack(sha1, repo->packs);
 699         if (!target)
 700                 return -1;
 701
 702         if (get_verbosely) {
 703                 fprintf(stderr, "Getting pack %s\n",
 704                         sha1_to_hex(target->sha1));
 705                 fprintf(stderr, " which contains %s\n",
 706                         sha1_to_hex(sha1));
 707         }
 708
 709         url = xmalloc(strlen(repo->base) + 65);
 710         sprintf(url, "%s/objects/pack/pack-%s.pack",
 711                 repo->base, sha1_to_hex(target->sha1));
 712
 713         filename = sha1_pack_name(target->sha1);
 714         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 715         packfile = fopen(tmpfile, "a");
 716         if (!packfile)
 717                 return error("Unable to open local file %s for pack",
 718                              filename);
 719
 720         slot = get_active_slot();
 721         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 722         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 723         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 724         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 725         slot->local = packfile;
 726
 727         /* If there is data present from a previous transfer attempt,
 728            resume where it left off */
 729         prev_posn = ftell(packfile);
 730         if (prev_posn>0) {
 731                 if (get_verbosely)
 732                         fprintf(stderr,
 733                                 "Resuming fetch of pack %s at byte %ld\n",
 734                                 sha1_to_hex(target->sha1), prev_posn);
 735                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 736                 range_header = curl_slist_append(range_header, range);
 737                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 738         }
 739
 740         if (start_active_slot(slot)) {
 741                 run_active_slot(slot);
 742                 if (slot->curl_result != CURLE_OK) {
 743                         fclose(packfile);
 744                         return error("Unable to get pack file %s\n%s", url,
 745                                      curl_errorstr);
 746                 }
 747         } else {
 748                 fclose(packfile);
 749                 return error("Unable to start request");
 750         }
 751
 752         fclose(packfile);
 753
 754         ret = move_temp_to_file(tmpfile, filename);
 755         if (ret)
 756                 return ret;
 757
 758         lst = &repo->packs;
 759         while (*lst != target)
 760                 lst = &((*lst)->next);
 761         *lst = (*lst)->next;
 762
 763         if (verify_pack(target, 0))
 764                 return -1;
 765         install_packed_git(target);
 766
 767         return 0;
 768 }
 769
 770 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 771 {
 772         char *hex = sha1_to_hex(sha1);
 773         int ret = 0;
 774         struct object_request *obj_req = object_queue_head;
 775
 776         while (obj_req != NULL && memcmp(obj_req->sha1, sha1, 20))
 777                 obj_req = obj_req->next;
 778         if (obj_req == NULL)
 779                 return error("Couldn't find request for %s in the queue", hex);
 780
 781         if (has_sha1_file(obj_req->sha1)) {
 782                 release_object_request(obj_req);
 783                 return 0;
 784         }
 785
 786 #ifdef USE_CURL_MULTI
 787         while (obj_req->state == WAITING) {
 788                 step_active_slots();
 789         }
 790 #else
 791         start_object_request(obj_req);
 792 #endif
 793
 794         while (obj_req->state == ACTIVE) {
 795                 run_active_slot(obj_req->slot);
 796         }
 797         if (obj_req->local != -1) {
 798                 close(obj_req->local); obj_req->local = -1;
 799         }
 800
 801         if (obj_req->state == ABORTED) {
 802                 ret = error("Request for %s aborted", hex);
 803         } else if (obj_req->curl_result != CURLE_OK &&
 804                    obj_req->http_code != 416) {
 805                 if (obj_req->http_code == 404)
 806                         ret = -1; /* Be silent, it is probably in a pack. */
 807                 else
 808                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 809                                     obj_req->errorstr, obj_req->curl_result,
 810                                     obj_req->http_code, hex);
 811         } else if (obj_req->zret != Z_STREAM_END) {
 812                 ret = error("File %s (%s) corrupt\n", hex, obj_req->url);
 813         } else if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 814                 ret = error("File %s has bad hash\n", hex);
 815         } else if (obj_req->rename < 0) {
 816                 ret = error("unable to write sha1 filename %s: %s",
 817                             obj_req->filename,
 818                             strerror(obj_req->rename));
 819         }
 820
 821         release_object_request(obj_req);
 822         return ret;
 823 }
 824
 825 int fetch(unsigned char *sha1)
 826 {
 827         struct alt_base *altbase = alt;
 828
 829         if (!fetch_object(altbase, sha1))
 830                 return 0;
 831         while (altbase) {
 832                 if (!fetch_pack(altbase, sha1))
 833                         return 0;
 834                 fetch_alternates(alt->base);
 835                 altbase = altbase->next;
 836         }
 837         return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
 838                      alt->base);
 839 }
 840
 841 static inline int needs_quote(int ch)
 842 {
 843         switch (ch) {
 844         case '/': case '-': case '.':
 845         case 'A'...'Z': case 'a'...'z': case '0'...'9':
 846                 return 0;
 847         default:
 848                 return 1;
 849         }
 850 }
 851
 852 static inline int hex(int v)
 853 {
 854         if (v < 10) return '0' + v;
 855         else return 'A' + v - 10;
 856 }
 857
 858 static char *quote_ref_url(const char *base, const char *ref)
 859 {
 860         const char *cp;
 861         char *dp, *qref;
 862         int len, baselen, ch;
 863
 864         baselen = strlen(base);
 865         len = baselen + 6; /* "refs/" + NUL */
 866         for (cp = ref; (ch = *cp) != 0; cp++, len++)
 867                 if (needs_quote(ch))
 868                         len += 2; /* extra two hex plus replacement % */
 869         qref = xmalloc(len);
 870         memcpy(qref, base, baselen);
 871         memcpy(qref + baselen, "refs/", 5);
 872         for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
 873                 if (needs_quote(ch)) {
 874                         *dp++ = '%';
 875                         *dp++ = hex((ch >> 4) & 0xF);
 876                         *dp++ = hex(ch & 0xF);
 877                 }
 878                 else
 879                         *dp++ = ch;
 880         }
 881         *dp = 0;
 882
 883         return qref;
 884 }
 885
 886 int fetch_ref(char *ref, unsigned char *sha1)
 887 {
 888         char *url;
 889         char hex[42];
 890         struct buffer buffer;
 891         char *base = alt->base;
 892         struct active_request_slot *slot;
 893         buffer.size = 41;
 894         buffer.posn = 0;
 895         buffer.buffer = hex;
 896         hex[41] = '\0';
 897
 898         url = quote_ref_url(base, ref);
 899         slot = get_active_slot();
 900         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 901         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 902         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 903         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 904         if (start_active_slot(slot)) {
 905                 run_active_slot(slot);
 906                 if (slot->curl_result != CURLE_OK)
 907                         return error("Couldn't get %s for %s\n%s",
 908                                      url, ref, curl_errorstr);
 909         } else {
 910                 return error("Unable to start request");
 911         }
 912
 913         hex[40] = '\0';
 914         get_sha1_hex(hex, sha1);
 915         return 0;
 916 }
 917
 918 int main(int argc, char **argv)
 919 {
 920         char *commit_id;
 921         char *url;
 922         int arg = 1;
 923         int rc = 0;
 924
 925         setup_git_directory();
 926
 927         while (arg < argc && argv[arg][0] == '-') {
 928                 if (argv[arg][1] == 't') {
 929                         get_tree = 1;
 930                 } else if (argv[arg][1] == 'c') {
 931                         get_history = 1;
 932                 } else if (argv[arg][1] == 'a') {
 933                         get_all = 1;
 934                         get_tree = 1;
 935                         get_history = 1;
 936                 } else if (argv[arg][1] == 'v') {
 937                         get_verbosely = 1;
 938                 } else if (argv[arg][1] == 'w') {
 939                         write_ref = argv[arg + 1];
 940                         arg++;
 941                 } else if (!strcmp(argv[arg], "--recover")) {
 942                         get_recover = 1;
 943                 }
 944                 arg++;
 945         }
 946         if (argc < arg + 2) {
 947                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
 948                 return 1;
 949         }
 950         commit_id = argv[arg];
 951         url = argv[arg + 1];
 952
 953         http_init();
 954
 955         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 956
 957         alt = xmalloc(sizeof(*alt));
 958         alt->base = url;
 959         alt->got_indices = 0;
 960         alt->packs = NULL;
 961         alt->next = NULL;
 962
 963         if (pull(commit_id))
 964                 rc = 1;
 965
 966         curl_slist_free_all(no_pragma_header);
 967
 968         http_cleanup();
 969
 970         return rc;
 971 }