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
 379         if (has_pack_index(sha1))
 380                 return 0;
 381
 382         if (get_verbosely)
 383                 fprintf(stderr, "Getting index for pack %s\n", hex);
 384
 385         url = xmalloc(strlen(repo->base) + 64);
 386         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 387
 388         filename = sha1_pack_index_name(sha1);
 389         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 390         indexfile = fopen(tmpfile, "a");
 391         if (!indexfile)
 392                 return error("Unable to open local file %s for pack index",
 393                              filename);
 394
 395         slot = get_active_slot();
 396         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 397         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 398         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 399         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 400         slot->local = indexfile;
 401
 402         /* If there is data present from a previous transfer attempt,
 403            resume where it left off */
 404         prev_posn = ftell(indexfile);
 405         if (prev_posn>0) {
 406                 if (get_verbosely)
 407                         fprintf(stderr,
 408                                 "Resuming fetch of index for pack %s at byte %ld\n",
 409                                 hex, prev_posn);
 410                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 411                 range_header = curl_slist_append(range_header, range);
 412                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 413         }
 414
 415         if (start_active_slot(slot)) {
 416                 run_active_slot(slot);
 417                 if (slot->curl_result != CURLE_OK) {
 418                         fclose(indexfile);
 419                         return error("Unable to get pack index %s\n%s", url,
 420                                      curl_errorstr);
 421                 }
 422         } else {
 423                 fclose(indexfile);
 424                 return error("Unable to start request");
 425         }
 426
 427         fclose(indexfile);
 428
 429         return move_temp_to_file(tmpfile, filename);
 430 }
 431
 432 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 433 {
 434         struct packed_git *new_pack;
 435         if (has_pack_file(sha1))
 436                 return 0; // don't list this as something we can get
 437
 438         if (fetch_index(repo, sha1))
 439                 return -1;
 440
 441         new_pack = parse_pack_index(sha1);
 442         new_pack->next = repo->packs;
 443         repo->packs = new_pack;
 444         return 0;
 445 }
 446
 447 static void process_alternates_response(void *callback_data)
 448 {
 449         struct alternates_request *alt_req =
 450                 (struct alternates_request *)callback_data;
 451         struct active_request_slot *slot = alt_req->slot;
 452         struct alt_base *tail = alt;
 453         char *base = alt_req->base;
 454         static const char null_byte = '\0';
 455         char *data;
 456         int i = 0;
 457
 458         if (alt_req->http_specific) {
 459                 if (slot->curl_result != CURLE_OK ||
 460                     !alt_req->buffer->posn) {
 461
 462                         /* Try reusing the slot to get non-http alternates */
 463                         alt_req->http_specific = 0;
 464                         sprintf(alt_req->url, "%s/objects/info/alternates",
 465                                 base);
 466                         curl_easy_setopt(slot->curl, CURLOPT_URL,
 467                                          alt_req->url);
 468                         active_requests++;
 469                         slot->in_use = 1;
 470                         if (start_active_slot(slot)) {
 471                                 return;
 472                         } else {
 473                                 got_alternates = -1;
 474                                 slot->in_use = 0;
 475                                 return;
 476                         }
 477                 }
 478         } else if (slot->curl_result != CURLE_OK) {
 479                 if (slot->http_code != 404 &&
 480                     slot->curl_result != CURLE_FILE_COULDNT_READ_FILE) {
 481                         got_alternates = -1;
 482                         return;
 483                 }
 484         }
 485
 486         fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 487         alt_req->buffer->posn--;
 488         data = alt_req->buffer->buffer;
 489
 490         while (i < alt_req->buffer->posn) {
 491                 int posn = i;
 492                 while (posn < alt_req->buffer->posn && data[posn] != '\n')
 493                         posn++;
 494                 if (data[posn] == '\n') {
 495                         int okay = 0;
 496                         int serverlen = 0;
 497                         struct alt_base *newalt;
 498                         char *target = NULL;
 499                         if (data[i] == '/') {
 500                                 serverlen = strchr(base + 8, '/') - base;
 501                                 okay = 1;
 502                         } else if (!memcmp(data + i, "../", 3)) {
 503                                 i += 3;
 504                                 serverlen = strlen(base);
 505                                 while (i + 2 < posn &&
 506                                        !memcmp(data + i, "../", 3)) {
 507                                         do {
 508                                                 serverlen--;
 509                                         } while (serverlen &&
 510                                                  base[serverlen - 1] != '/');
 511                                         i += 3;
 512                                 }
 513                                 // If the server got removed, give up.
 514                                 okay = strchr(base, ':') - base + 3 <
 515                                         serverlen;
 516                         } else if (alt_req->http_specific) {
 517                                 char *colon = strchr(data + i, ':');
 518                                 char *slash = strchr(data + i, '/');
 519                                 if (colon && slash && colon < data + posn &&
 520                                     slash < data + posn && colon < slash) {
 521                                         okay = 1;
 522                                 }
 523                         }
 524                         // skip 'objects' at end
 525                         if (okay) {
 526                                 target = xmalloc(serverlen + posn - i - 6);
 527                                 strncpy(target, base, serverlen);
 528                                 strncpy(target + serverlen, data + i,
 529                                         posn - i - 7);
 530                                 target[serverlen + posn - i - 7] = '\0';
 531                                 if (get_verbosely)
 532                                         fprintf(stderr,
 533                                                 "Also look at %s\n", target);
 534                                 newalt = xmalloc(sizeof(*newalt));
 535                                 newalt->next = NULL;
 536                                 newalt->base = target;
 537                                 newalt->got_indices = 0;
 538                                 newalt->packs = NULL;
 539                                 while (tail->next != NULL)
 540                                         tail = tail->next;
 541                                 tail->next = newalt;
 542                         }
 543                 }
 544                 i = posn + 1;
 545         }
 546
 547         got_alternates = 1;
 548 }
 549
 550 static void fetch_alternates(char *base)
 551 {
 552         struct buffer buffer;
 553         char *url;
 554         char *data;
 555         struct active_request_slot *slot;
 556         static struct alternates_request alt_req;
 557
 558         /* If another request has already started fetching alternates,
 559            wait for them to arrive and return to processing this request's
 560            curl message */
 561 #ifdef USE_CURL_MULTI
 562         while (got_alternates == 0) {
 563                 step_active_slots();
 564         }
 565 #endif
 566
 567         /* Nothing to do if they've already been fetched */
 568         if (got_alternates == 1)
 569                 return;
 570
 571         /* Start the fetch */
 572         got_alternates = 0;
 573
 574         data = xmalloc(4096);
 575         buffer.size = 4096;
 576         buffer.posn = 0;
 577         buffer.buffer = data;
 578
 579         if (get_verbosely)
 580                 fprintf(stderr, "Getting alternates list for %s\n", base);
 581
 582         url = xmalloc(strlen(base) + 31);
 583         sprintf(url, "%s/objects/info/http-alternates", base);
 584
 585         /* Use a callback to process the result, since another request
 586            may fail and need to have alternates loaded before continuing */
 587         slot = get_active_slot();
 588         slot->callback_func = process_alternates_response;
 589         slot->callback_data = &alt_req;
 590
 591         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 592         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 593         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 594
 595         alt_req.base = base;
 596         alt_req.url = url;
 597         alt_req.buffer = &buffer;
 598         alt_req.http_specific = 1;
 599         alt_req.slot = slot;
 600
 601         if (start_active_slot(slot))
 602                 run_active_slot(slot);
 603         else
 604                 got_alternates = -1;
 605
 606         free(data);
 607         free(url);
 608 }
 609
 610 static int fetch_indices(struct alt_base *repo)
 611 {
 612         unsigned char sha1[20];
 613         char *url;
 614         struct buffer buffer;
 615         char *data;
 616         int i = 0;
 617
 618         struct active_request_slot *slot;
 619
 620         if (repo->got_indices)
 621                 return 0;
 622
 623         data = xmalloc(4096);
 624         buffer.size = 4096;
 625         buffer.posn = 0;
 626         buffer.buffer = data;
 627
 628         if (get_verbosely)
 629                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
 630
 631         url = xmalloc(strlen(repo->base) + 21);
 632         sprintf(url, "%s/objects/info/packs", repo->base);
 633
 634         slot = get_active_slot();
 635         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 636         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 637         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 638         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 639         if (start_active_slot(slot)) {
 640                 run_active_slot(slot);
 641                 if (slot->curl_result != CURLE_OK) {
 642                         if (slot->http_code == 404 ||
 643                             slot->curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 644                                 repo->got_indices = 1;
 645                                 free(buffer.buffer);
 646                                 return 0;
 647                         } else {
 648                                 repo->got_indices = 0;
 649                                 free(buffer.buffer);
 650                                 return error("%s", curl_errorstr);
 651                         }
 652                 }
 653         } else {
 654                 repo->got_indices = 0;
 655                 free(buffer.buffer);
 656                 return error("Unable to start request");
 657         }
 658
 659         data = buffer.buffer;
 660         while (i < buffer.posn) {
 661                 switch (data[i]) {
 662                 case 'P':
 663                         i++;
 664                         if (i + 52 <= buffer.posn &&
 665                             !strncmp(data + i, " pack-", 6) &&
 666                             !strncmp(data + i + 46, ".pack\n", 6)) {
 667                                 get_sha1_hex(data + i + 6, sha1);
 668                                 setup_index(repo, sha1);
 669                                 i += 51;
 670                                 break;
 671                         }
 672                 default:
 673                         while (i < buffer.posn && data[i] != '\n')
 674                                 i++;
 675                 }
 676                 i++;
 677         }
 678
 679         free(buffer.buffer);
 680         repo->got_indices = 1;
 681         return 0;
 682 }
 683
 684 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 685 {
 686         char *url;
 687         struct packed_git *target;
 688         struct packed_git **lst;
 689         FILE *packfile;
 690         char *filename;
 691         char tmpfile[PATH_MAX];
 692         int ret;
 693         long prev_posn = 0;
 694         char range[RANGE_HEADER_SIZE];
 695         struct curl_slist *range_header = NULL;
 696
 697         struct active_request_slot *slot;
 698
 699         if (fetch_indices(repo))
 700                 return -1;
 701         target = find_sha1_pack(sha1, repo->packs);
 702         if (!target)
 703                 return -1;
 704
 705         if (get_verbosely) {
 706                 fprintf(stderr, "Getting pack %s\n",
 707                         sha1_to_hex(target->sha1));
 708                 fprintf(stderr, " which contains %s\n",
 709                         sha1_to_hex(sha1));
 710         }
 711
 712         url = xmalloc(strlen(repo->base) + 65);
 713         sprintf(url, "%s/objects/pack/pack-%s.pack",
 714                 repo->base, sha1_to_hex(target->sha1));
 715
 716         filename = sha1_pack_name(target->sha1);
 717         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 718         packfile = fopen(tmpfile, "a");
 719         if (!packfile)
 720                 return error("Unable to open local file %s for pack",
 721                              filename);
 722
 723         slot = get_active_slot();
 724         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 725         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 726         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 727         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 728         slot->local = packfile;
 729
 730         /* If there is data present from a previous transfer attempt,
 731            resume where it left off */
 732         prev_posn = ftell(packfile);
 733         if (prev_posn>0) {
 734                 if (get_verbosely)
 735                         fprintf(stderr,
 736                                 "Resuming fetch of pack %s at byte %ld\n",
 737                                 sha1_to_hex(target->sha1), prev_posn);
 738                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 739                 range_header = curl_slist_append(range_header, range);
 740                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 741         }
 742
 743         if (start_active_slot(slot)) {
 744                 run_active_slot(slot);
 745                 if (slot->curl_result != CURLE_OK) {
 746                         fclose(packfile);
 747                         return error("Unable to get pack file %s\n%s", url,
 748                                      curl_errorstr);
 749                 }
 750         } else {
 751                 fclose(packfile);
 752                 return error("Unable to start request");
 753         }
 754
 755         fclose(packfile);
 756
 757         ret = move_temp_to_file(tmpfile, filename);
 758         if (ret)
 759                 return ret;
 760
 761         lst = &repo->packs;
 762         while (*lst != target)
 763                 lst = &((*lst)->next);
 764         *lst = (*lst)->next;
 765
 766         if (verify_pack(target, 0))
 767                 return -1;
 768         install_packed_git(target);
 769
 770         return 0;
 771 }
 772
 773 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 774 {
 775         char *hex = sha1_to_hex(sha1);
 776         int ret = 0;
 777         struct object_request *obj_req = object_queue_head;
 778
 779         while (obj_req != NULL && memcmp(obj_req->sha1, sha1, 20))
 780                 obj_req = obj_req->next;
 781         if (obj_req == NULL)
 782                 return error("Couldn't find request for %s in the queue", hex);
 783
 784         if (has_sha1_file(obj_req->sha1)) {
 785                 release_object_request(obj_req);
 786                 return 0;
 787         }
 788
 789 #ifdef USE_CURL_MULTI
 790         while (obj_req->state == WAITING) {
 791                 step_active_slots();
 792         }
 793 #else
 794         start_object_request(obj_req);
 795 #endif
 796
 797         while (obj_req->state == ACTIVE) {
 798                 run_active_slot(obj_req->slot);
 799         }
 800         if (obj_req->local != -1) {
 801                 close(obj_req->local); obj_req->local = -1;
 802         }
 803
 804         if (obj_req->state == ABORTED) {
 805                 ret = error("Request for %s aborted", hex);
 806         } else if (obj_req->curl_result != CURLE_OK &&
 807                    obj_req->http_code != 416) {
 808                 if (obj_req->http_code == 404 ||
 809                     obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE)
 810                         ret = -1; /* Be silent, it is probably in a pack. */
 811                 else
 812                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 813                                     obj_req->errorstr, obj_req->curl_result,
 814                                     obj_req->http_code, hex);
 815         } else if (obj_req->zret != Z_STREAM_END) {
 816                 ret = error("File %s (%s) corrupt\n", hex, obj_req->url);
 817         } else if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 818                 ret = error("File %s has bad hash\n", hex);
 819         } else if (obj_req->rename < 0) {
 820                 ret = error("unable to write sha1 filename %s: %s",
 821                             obj_req->filename,
 822                             strerror(obj_req->rename));
 823         }
 824
 825         release_object_request(obj_req);
 826         return ret;
 827 }
 828
 829 int fetch(unsigned char *sha1)
 830 {
 831         struct alt_base *altbase = alt;
 832
 833         if (!fetch_object(altbase, sha1))
 834                 return 0;
 835         while (altbase) {
 836                 if (!fetch_pack(altbase, sha1))
 837                         return 0;
 838                 fetch_alternates(alt->base);
 839                 altbase = altbase->next;
 840         }
 841         return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
 842                      alt->base);
 843 }
 844
 845 static inline int needs_quote(int ch)
 846 {
 847         switch (ch) {
 848         case '/': case '-': case '.':
 849         case 'A'...'Z': case 'a'...'z': case '0'...'9':
 850                 return 0;
 851         default:
 852                 return 1;
 853         }
 854 }
 855
 856 static inline int hex(int v)
 857 {
 858         if (v < 10) return '0' + v;
 859         else return 'A' + v - 10;
 860 }
 861
 862 static char *quote_ref_url(const char *base, const char *ref)
 863 {
 864         const char *cp;
 865         char *dp, *qref;
 866         int len, baselen, ch;
 867
 868         baselen = strlen(base);
 869         len = baselen + 6; /* "refs/" + NUL */
 870         for (cp = ref; (ch = *cp) != 0; cp++, len++)
 871                 if (needs_quote(ch))
 872                         len += 2; /* extra two hex plus replacement % */
 873         qref = xmalloc(len);
 874         memcpy(qref, base, baselen);
 875         memcpy(qref + baselen, "refs/", 5);
 876         for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
 877                 if (needs_quote(ch)) {
 878                         *dp++ = '%';
 879                         *dp++ = hex((ch >> 4) & 0xF);
 880                         *dp++ = hex(ch & 0xF);
 881                 }
 882                 else
 883                         *dp++ = ch;
 884         }
 885         *dp = 0;
 886
 887         return qref;
 888 }
 889
 890 int fetch_ref(char *ref, unsigned char *sha1)
 891 {
 892         char *url;
 893         char hex[42];
 894         struct buffer buffer;
 895         char *base = alt->base;
 896         struct active_request_slot *slot;
 897         buffer.size = 41;
 898         buffer.posn = 0;
 899         buffer.buffer = hex;
 900         hex[41] = '\0';
 901
 902         url = quote_ref_url(base, ref);
 903         slot = get_active_slot();
 904         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 905         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 906         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 907         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 908         if (start_active_slot(slot)) {
 909                 run_active_slot(slot);
 910                 if (slot->curl_result != CURLE_OK)
 911                         return error("Couldn't get %s for %s\n%s",
 912                                      url, ref, curl_errorstr);
 913         } else {
 914                 return error("Unable to start request");
 915         }
 916
 917         hex[40] = '\0';
 918         get_sha1_hex(hex, sha1);
 919         return 0;
 920 }
 921
 922 int main(int argc, char **argv)
 923 {
 924         char *commit_id;
 925         char *url;
 926         int arg = 1;
 927         int rc = 0;
 928
 929         setup_git_directory();
 930
 931         while (arg < argc && argv[arg][0] == '-') {
 932                 if (argv[arg][1] == 't') {
 933                         get_tree = 1;
 934                 } else if (argv[arg][1] == 'c') {
 935                         get_history = 1;
 936                 } else if (argv[arg][1] == 'a') {
 937                         get_all = 1;
 938                         get_tree = 1;
 939                         get_history = 1;
 940                 } else if (argv[arg][1] == 'v') {
 941                         get_verbosely = 1;
 942                 } else if (argv[arg][1] == 'w') {
 943                         write_ref = argv[arg + 1];
 944                         arg++;
 945                 } else if (!strcmp(argv[arg], "--recover")) {
 946                         get_recover = 1;
 947                 }
 948                 arg++;
 949         }
 950         if (argc < arg + 2) {
 951                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
 952                 return 1;
 953         }
 954         commit_id = argv[arg];
 955         url = argv[arg + 1];
 956
 957         http_init();
 958
 959         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 960
 961         alt = xmalloc(sizeof(*alt));
 962         alt->base = url;
 963         alt->got_indices = 0;
 964         alt->packs = NULL;
 965         alt->next = NULL;
 966
 967         if (pull(commit_id))
 968                 rc = 1;
 969
 970         curl_slist_free_all(no_pragma_header);
 971
 972         http_cleanup();
 973
 974         return rc;
 975 }