http-fetch.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "pack.h"
   4 #include "fetch.h"
   5
   6 #include <curl/curl.h>
   7 #include <curl/easy.h>
   8
   9 #if LIBCURL_VERSION_NUM >= 0x070908
  10 #define USE_CURL_MULTI
  11 #define DEFAULT_MAX_REQUESTS 5
  12 #endif
  13
  14 #if LIBCURL_VERSION_NUM < 0x070704
  15 #define curl_global_cleanup() do { /* nothing */ } while(0)
  16 #endif
  17 #if LIBCURL_VERSION_NUM < 0x070800
  18 #define curl_global_init(a) do { /* nothing */ } while(0)
  19 #endif
  20
  21 #define PREV_BUF_SIZE 4096
  22 #define RANGE_HEADER_SIZE 30
  23
  24 static int active_requests = 0;
  25 static int data_received;
  26
  27 #ifdef USE_CURL_MULTI
  28 static int max_requests = DEFAULT_MAX_REQUESTS;
  29 static CURLM *curlm;
  30 #endif
  31 static CURL *curl_default;
  32 static struct curl_slist *no_pragma_header;
  33 static struct curl_slist *no_range_header;
  34 static char curl_errorstr[CURL_ERROR_SIZE];
  35
  36 struct alt_base
  37 {
  38         char *base;
  39         int got_indices;
  40         struct packed_git *packs;
  41         struct alt_base *next;
  42 };
  43
  44 static struct alt_base *alt = NULL;
  45
  46 enum transfer_state {
  47         WAITING,
  48         ABORTED,
  49         ACTIVE,
  50         COMPLETE,
  51 };
  52
  53 struct transfer_request
  54 {
  55         unsigned char sha1[20];
  56         struct alt_base *repo;
  57         char *url;
  58         char filename[PATH_MAX];
  59         char tmpfile[PATH_MAX];
  60         int local;
  61         enum transfer_state state;
  62         CURLcode curl_result;
  63         char errorstr[CURL_ERROR_SIZE];
  64         long http_code;
  65         unsigned char real_sha1[20];
  66         SHA_CTX c;
  67         z_stream stream;
  68         int zret;
  69         int rename;
  70         struct active_request_slot *slot;
  71         struct transfer_request *next;
  72 };
  73
  74 struct active_request_slot
  75 {
  76         CURL *curl;
  77         FILE *local;
  78         int in_use;
  79         int done;
  80         CURLcode curl_result;
  81         struct active_request_slot *next;
  82 };
  83
  84 static struct transfer_request *request_queue_head = NULL;
  85 static struct active_request_slot *active_queue_head = NULL;
  86
  87 static int curl_ssl_verify;
  88 static char *ssl_cert;
  89 static char *ssl_key;
  90 static char *ssl_capath;
  91 static char *ssl_cainfo;
  92
  93 struct buffer
  94 {
  95         size_t posn;
  96         size_t size;
  97         void *buffer;
  98 };
  99
 100 static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
 101                             struct buffer *buffer)
 102 {
 103         size_t size = eltsize * nmemb;
 104         if (size > buffer->size - buffer->posn)
 105                 size = buffer->size - buffer->posn;
 106         memcpy(buffer->buffer + buffer->posn, ptr, size);
 107         buffer->posn += size;
 108         data_received++;
 109         return size;
 110 }
 111
 112 static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 113                                void *data)
 114 {
 115         unsigned char expn[4096];
 116         size_t size = eltsize * nmemb;
 117         int posn = 0;
 118         struct transfer_request *request = (struct transfer_request *)data;
 119         do {
 120                 ssize_t retval = write(request->local,
 121                                        ptr + posn, size - posn);
 122                 if (retval < 0)
 123                         return posn;
 124                 posn += retval;
 125         } while (posn < size);
 126
 127         request->stream.avail_in = size;
 128         request->stream.next_in = ptr;
 129         do {
 130                 request->stream.next_out = expn;
 131                 request->stream.avail_out = sizeof(expn);
 132                 request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
 133                 SHA1_Update(&request->c, expn,
 134                             sizeof(expn) - request->stream.avail_out);
 135         } while (request->stream.avail_in && request->zret == Z_OK);
 136         data_received++;
 137         return size;
 138 }
 139
 140 int relink_or_rename(char *old, char *new) {
 141         int ret;
 142
 143         ret = link(old, new);
 144         if (ret < 0) {
 145                 /* Same Coda hack as in write_sha1_file(sha1_file.c) */
 146                 ret = errno;
 147                 if (ret == EXDEV && !rename(old, new))
 148                         return 0;
 149         }
 150         unlink(old);
 151         if (ret) {
 152                 if (ret != EEXIST)
 153                         return ret;
 154         }
 155
 156         return 0;
 157 }
 158
 159 #ifdef USE_CURL_MULTI
 160 void process_curl_messages();
 161 void process_request_queue();
 162 #endif
 163
 164 struct active_request_slot *get_active_slot()
 165 {
 166         struct active_request_slot *slot = active_queue_head;
 167         struct active_request_slot *newslot;
 168
 169 #ifdef USE_CURL_MULTI
 170         int num_transfers;
 171
 172         /* Wait for a slot to open up if the queue is full */
 173         while (active_requests >= max_requests) {
 174                 curl_multi_perform(curlm, &num_transfers);
 175                 if (num_transfers < active_requests) {
 176                         process_curl_messages();
 177                 }
 178         }
 179 #endif
 180
 181         while (slot != NULL && slot->in_use) {
 182                 slot = slot->next;
 183         }
 184         if (slot == NULL) {
 185                 newslot = xmalloc(sizeof(*newslot));
 186                 newslot->curl = curl_easy_duphandle(curl_default);
 187                 newslot->in_use = 0;
 188                 newslot->next = NULL;
 189
 190                 slot = active_queue_head;
 191                 if (slot == NULL) {
 192                         active_queue_head = newslot;
 193                 } else {
 194                         while (slot->next != NULL) {
 195                                 slot = slot->next;
 196                         }
 197                         slot->next = newslot;
 198                 }
 199                 slot = newslot;
 200         }
 201
 202         active_requests++;
 203         slot->in_use = 1;
 204         slot->done = 0;
 205         slot->local = NULL;
 206         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 207         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 208         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 209
 210         return slot;
 211 }
 212
 213 int start_active_slot(struct active_request_slot *slot)
 214 {
 215 #ifdef USE_CURL_MULTI
 216         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 217
 218         if (curlm_result != CURLM_OK &&
 219             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 220                 active_requests--;
 221                 slot->in_use = 0;
 222                 return 0;
 223         }
 224 #endif
 225         return 1;
 226 }
 227
 228 void run_active_slot(struct active_request_slot *slot)
 229 {
 230 #ifdef USE_CURL_MULTI
 231         int num_transfers;
 232         long last_pos = 0;
 233         long current_pos;
 234         fd_set readfds;
 235         fd_set writefds;
 236         fd_set excfds;
 237         int max_fd;
 238         struct timeval select_timeout;
 239         CURLMcode curlm_result;
 240
 241         while (!slot->done) {
 242                 data_received = 0;
 243                 do {
 244                         curlm_result = curl_multi_perform(curlm,
 245                                                           &num_transfers);
 246                 } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 247                 if (num_transfers < active_requests) {
 248                         process_curl_messages();
 249                         process_request_queue();
 250                 }
 251
 252                 if (!data_received && slot->local != NULL) {
 253                         current_pos = ftell(slot->local);
 254                         if (current_pos > last_pos)
 255                                 data_received++;
 256                         last_pos = current_pos;
 257                 }
 258
 259                 if (!slot->done && !data_received) {
 260                         max_fd = 0;
 261                         FD_ZERO(&readfds);
 262                         FD_ZERO(&writefds);
 263                         FD_ZERO(&excfds);
 264                         select_timeout.tv_sec = 0;
 265                         select_timeout.tv_usec = 50000;
 266                         select(max_fd, &readfds, &writefds,
 267                                &excfds, &select_timeout);
 268                 }
 269         }
 270 #else
 271         slot->curl_result = curl_easy_perform(slot->curl);
 272         active_requests--;
 273 #endif
 274 }
 275
 276 void start_request(struct transfer_request *request)
 277 {
 278         char *hex = sha1_to_hex(request->sha1);
 279         char prevfile[PATH_MAX];
 280         char *url;
 281         char *posn;
 282         int prevlocal;
 283         unsigned char prev_buf[PREV_BUF_SIZE];
 284         ssize_t prev_read = 0;
 285         long prev_posn = 0;
 286         char range[RANGE_HEADER_SIZE];
 287         struct curl_slist *range_header = NULL;
 288         struct active_request_slot *slot;
 289
 290         snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 291         unlink(prevfile);
 292         rename(request->tmpfile, prevfile);
 293         unlink(request->tmpfile);
 294
 295         request->local = open(request->tmpfile,
 296                               O_WRONLY | O_CREAT | O_EXCL, 0666);
 297         if (request->local < 0) {
 298                 request->state = ABORTED;
 299                 error("Couldn't create temporary file %s for %s: %s\n",
 300                       request->tmpfile, request->filename, strerror(errno));
 301                 return;
 302         }
 303
 304         memset(&request->stream, 0, sizeof(request->stream));
 305
 306         inflateInit(&request->stream);
 307
 308         SHA1_Init(&request->c);
 309
 310         url = xmalloc(strlen(request->repo->base) + 50);
 311         request->url = xmalloc(strlen(request->repo->base) + 50);
 312         strcpy(url, request->repo->base);
 313         posn = url + strlen(request->repo->base);
 314         strcpy(posn, "objects/");
 315         posn += 8;
 316         memcpy(posn, hex, 2);
 317         posn += 2;
 318         *(posn++) = '/';
 319         strcpy(posn, hex + 2);
 320         strcpy(request->url, url);
 321
 322         /* If a previous temp file is present, process what was already
 323            fetched. */
 324         prevlocal = open(prevfile, O_RDONLY);
 325         if (prevlocal != -1) {
 326                 do {
 327                         prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 328                         if (prev_read>0) {
 329                                 if (fwrite_sha1_file(prev_buf,
 330                                                      1,
 331                                                      prev_read,
 332                                                      request) == prev_read) {
 333                                         prev_posn += prev_read;
 334                                 } else {
 335                                         prev_read = -1;
 336                                 }
 337                         }
 338                 } while (prev_read > 0);
 339                 close(prevlocal);
 340         }
 341         unlink(prevfile);
 342
 343         /* Reset inflate/SHA1 if there was an error reading the previous temp
 344            file; also rewind to the beginning of the local file. */
 345         if (prev_read == -1) {
 346                 memset(&request->stream, 0, sizeof(request->stream));
 347                 inflateInit(&request->stream);
 348                 SHA1_Init(&request->c);
 349                 if (prev_posn>0) {
 350                         prev_posn = 0;
 351                         lseek(request->local, SEEK_SET, 0);
 352                         ftruncate(request->local, 0);
 353                 }
 354         }
 355
 356         slot = get_active_slot();
 357         curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 358         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 359         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 360         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 361
 362         /* If we have successfully processed data from a previous fetch
 363            attempt, only fetch the data we don't already have. */
 364         if (prev_posn>0) {
 365                 if (get_verbosely)
 366                         fprintf(stderr,
 367                                 "Resuming fetch of object %s at byte %ld\n",
 368                                 hex, prev_posn);
 369                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 370                 range_header = curl_slist_append(range_header, range);
 371                 curl_easy_setopt(slot->curl,
 372                                  CURLOPT_HTTPHEADER, range_header);
 373         }
 374
 375         /* Try to get the request started, abort the request on error */
 376         if (!start_active_slot(slot)) {
 377                 request->state = ABORTED;
 378                 close(request->local);
 379                 free(request->url);
 380                 return;
 381         }
 382
 383         request->slot = slot;
 384         request->state = ACTIVE;
 385 }
 386
 387 void finish_request(struct transfer_request *request)
 388 {
 389         fchmod(request->local, 0444);
 390         close(request->local);
 391
 392         if (request->http_code == 416) {
 393                 fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 394         } else if (request->curl_result != CURLE_OK) {
 395                 return;
 396         }
 397
 398         inflateEnd(&request->stream);
 399         SHA1_Final(request->real_sha1, &request->c);
 400         if (request->zret != Z_STREAM_END) {
 401                 unlink(request->tmpfile);
 402                 return;
 403         }
 404         if (memcmp(request->sha1, request->real_sha1, 20)) {
 405                 unlink(request->tmpfile);
 406                 return;
 407         }
 408         request->rename =
 409                 relink_or_rename(request->tmpfile, request->filename);
 410
 411         if (request->rename == 0)
 412                 pull_say("got %s\n", sha1_to_hex(request->sha1));
 413 }
 414
 415 void release_request(struct transfer_request *request)
 416 {
 417         struct transfer_request *entry = request_queue_head;
 418
 419         if (request == request_queue_head) {
 420                 request_queue_head = request->next;
 421         } else {
 422                 while (entry->next != NULL && entry->next != request)
 423                         entry = entry->next;
 424                 if (entry->next == request)
 425                         entry->next = entry->next->next;
 426         }
 427
 428         free(request->url);
 429         free(request);
 430 }
 431
 432 #ifdef USE_CURL_MULTI
 433 void process_curl_messages()
 434 {
 435         int num_messages;
 436         struct active_request_slot *slot;
 437         struct transfer_request *request = NULL;
 438         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 439
 440         while (curl_message != NULL) {
 441                 if (curl_message->msg == CURLMSG_DONE) {
 442                         slot = active_queue_head;
 443                         while (slot != NULL &&
 444                                slot->curl != curl_message->easy_handle)
 445                                 slot = slot->next;
 446                         if (slot != NULL) {
 447                                 curl_multi_remove_handle(curlm, slot->curl);
 448                                 active_requests--;
 449                                 slot->done = 1;
 450                                 slot->in_use = 0;
 451                                 slot->curl_result = curl_message->data.result;
 452                                 request = request_queue_head;
 453                                 while (request != NULL &&
 454                                        request->slot != slot)
 455                                         request = request->next;
 456                         } else {
 457                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 458                         }
 459                         if (request != NULL) {
 460                                 request->curl_result =
 461                                         curl_message->data.result;
 462                                 curl_easy_getinfo(slot->curl,
 463                                                   CURLINFO_HTTP_CODE,
 464                                                   &request->http_code);
 465                                 request->slot = NULL;
 466
 467                                 /* Use alternates if necessary */
 468                                 if (request->http_code == 404 &&
 469                                     request->repo->next != NULL) {
 470                                         request->repo = request->repo->next;
 471                                         start_request(request);
 472                                 } else {
 473                                         finish_request(request);
 474                                         request->state = COMPLETE;
 475                                 }
 476                         }
 477                 } else {
 478                         fprintf(stderr, "Unknown CURL message received: %d\n",
 479                                 (int)curl_message->msg);
 480                 }
 481                 curl_message = curl_multi_info_read(curlm, &num_messages);
 482         }
 483 }
 484
 485 void process_request_queue()
 486 {
 487         struct transfer_request *request = request_queue_head;
 488         int num_transfers;
 489
 490         while (active_requests < max_requests && request != NULL) {
 491                 if (request->state == WAITING) {
 492                         start_request(request);
 493                         curl_multi_perform(curlm, &num_transfers);
 494                 }
 495                 request = request->next;
 496         }
 497 }
 498 #endif
 499
 500 void prefetch(unsigned char *sha1)
 501 {
 502         struct transfer_request *newreq;
 503         struct transfer_request *tail;
 504         char *filename = sha1_file_name(sha1);
 505
 506         newreq = xmalloc(sizeof(*newreq));
 507         memcpy(newreq->sha1, sha1, 20);
 508         newreq->repo = alt;
 509         newreq->url = NULL;
 510         newreq->local = -1;
 511         newreq->state = WAITING;
 512         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 513         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 514                  "%s.temp", filename);
 515         newreq->next = NULL;
 516
 517         if (request_queue_head == NULL) {
 518                 request_queue_head = newreq;
 519         } else {
 520                 tail = request_queue_head;
 521                 while (tail->next != NULL) {
 522                         tail = tail->next;
 523                 }
 524                 tail->next = newreq;
 525         }
 526 #ifdef USE_CURL_MULTI
 527         process_request_queue();
 528         process_curl_messages();
 529 #endif
 530 }
 531
 532 static int got_alternates = 0;
 533
 534 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 535 {
 536         char *hex = sha1_to_hex(sha1);
 537         char *filename;
 538         char *url;
 539         char tmpfile[PATH_MAX];
 540         int ret;
 541         long prev_posn = 0;
 542         char range[RANGE_HEADER_SIZE];
 543         struct curl_slist *range_header = NULL;
 544
 545         FILE *indexfile;
 546         struct active_request_slot *slot;
 547
 548         if (has_pack_index(sha1))
 549                 return 0;
 550
 551         if (get_verbosely)
 552                 fprintf(stderr, "Getting index for pack %s\n", hex);
 553
 554         url = xmalloc(strlen(repo->base) + 64);
 555         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 556
 557         filename = sha1_pack_index_name(sha1);
 558         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 559         indexfile = fopen(tmpfile, "a");
 560         if (!indexfile)
 561                 return error("Unable to open local file %s for pack index",
 562                              filename);
 563
 564         slot = get_active_slot();
 565         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 566         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 567         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 568         slot->local = indexfile;
 569
 570         /* If there is data present from a previous transfer attempt,
 571            resume where it left off */
 572         prev_posn = ftell(indexfile);
 573         if (prev_posn>0) {
 574                 if (get_verbosely)
 575                         fprintf(stderr,
 576                                 "Resuming fetch of index for pack %s at byte %ld\n",
 577                                 hex, prev_posn);
 578                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 579                 range_header = curl_slist_append(range_header, range);
 580                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 581         }
 582
 583         if (start_active_slot(slot)) {
 584                 run_active_slot(slot);
 585                 if (slot->curl_result != CURLE_OK) {
 586                         fclose(indexfile);
 587                         return error("Unable to get pack index %s\n%s", url,
 588                                      curl_errorstr);
 589                 }
 590         } else {
 591                 return error("Unable to start request");
 592         }
 593
 594         fclose(indexfile);
 595
 596         ret = relink_or_rename(tmpfile, filename);
 597         if (ret)
 598                 return error("unable to write index filename %s: %s",
 599                              filename, strerror(ret));
 600
 601         return 0;
 602 }
 603
 604 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 605 {
 606         struct packed_git *new_pack;
 607         if (has_pack_file(sha1))
 608                 return 0; // don't list this as something we can get
 609
 610         if (fetch_index(repo, sha1))
 611                 return -1;
 612
 613         new_pack = parse_pack_index(sha1);
 614         new_pack->next = repo->packs;
 615         repo->packs = new_pack;
 616         return 0;
 617 }
 618
 619 static int fetch_alternates(char *base)
 620 {
 621         int ret = 0;
 622         struct buffer buffer;
 623         char *url;
 624         char *data;
 625         int i = 0;
 626         int http_specific = 1;
 627         struct alt_base *tail = alt;
 628
 629         struct active_request_slot *slot;
 630         if (got_alternates)
 631                 return 0;
 632         data = xmalloc(4096);
 633         buffer.size = 4095;
 634         buffer.posn = 0;
 635         buffer.buffer = data;
 636
 637         if (get_verbosely)
 638                 fprintf(stderr, "Getting alternates list\n");
 639
 640         url = xmalloc(strlen(base) + 31);
 641         sprintf(url, "%s/objects/info/http-alternates", base);
 642
 643         slot = get_active_slot();
 644         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 645         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 646         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 647         if (start_active_slot(slot)) {
 648                 run_active_slot(slot);
 649                 if (slot->curl_result != CURLE_OK || !buffer.posn) {
 650                         http_specific = 0;
 651
 652                         sprintf(url, "%s/objects/info/alternates", base);
 653
 654                         slot = get_active_slot();
 655                         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 656                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 657                                          fwrite_buffer);
 658                         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 659                         if (start_active_slot(slot)) {
 660                                 run_active_slot(slot);
 661                                 if (slot->curl_result != CURLE_OK) {
 662                                         return 0;
 663                                 }
 664                         }
 665                 }
 666         } else {
 667                 return 0;
 668         }
 669
 670         data[buffer.posn] = '\0';
 671
 672         while (i < buffer.posn) {
 673                 int posn = i;
 674                 while (posn < buffer.posn && data[posn] != '\n')
 675                         posn++;
 676                 if (data[posn] == '\n') {
 677                         int okay = 0;
 678                         int serverlen = 0;
 679                         struct alt_base *newalt;
 680                         char *target = NULL;
 681                         if (data[i] == '/') {
 682                                 serverlen = strchr(base + 8, '/') - base;
 683                                 okay = 1;
 684                         } else if (!memcmp(data + i, "../", 3)) {
 685                                 i += 3;
 686                                 serverlen = strlen(base);
 687                                 while (i + 2 < posn &&
 688                                        !memcmp(data + i, "../", 3)) {
 689                                         do {
 690                                                 serverlen--;
 691                                         } while (serverlen &&
 692                                                  base[serverlen - 1] != '/');
 693                                         i += 3;
 694                                 }
 695                                 // If the server got removed, give up.
 696                                 okay = strchr(base, ':') - base + 3 <
 697                                         serverlen;
 698                         } else if (http_specific) {
 699                                 char *colon = strchr(data + i, ':');
 700                                 char *slash = strchr(data + i, '/');
 701                                 if (colon && slash && colon < data + posn &&
 702                                     slash < data + posn && colon < slash) {
 703                                         okay = 1;
 704                                 }
 705                         }
 706                         // skip 'objects' at end
 707                         if (okay) {
 708                                 target = xmalloc(serverlen + posn - i - 6);
 709                                 strncpy(target, base, serverlen);
 710                                 strncpy(target + serverlen, data + i,
 711                                         posn - i - 7);
 712                                 target[serverlen + posn - i - 7] = '\0';
 713                                 if (get_verbosely)
 714                                         fprintf(stderr,
 715                                                 "Also look at %s\n", target);
 716                                 newalt = xmalloc(sizeof(*newalt));
 717                                 newalt->next = NULL;
 718                                 newalt->base = target;
 719                                 newalt->got_indices = 0;
 720                                 newalt->packs = NULL;
 721                                 while (tail->next != NULL)
 722                                         tail = tail->next;
 723                                 tail->next = newalt;
 724                                 ret++;
 725                         }
 726                 }
 727                 i = posn + 1;
 728         }
 729         got_alternates = 1;
 730
 731         return ret;
 732 }
 733
 734 static int fetch_indices(struct alt_base *repo)
 735 {
 736         unsigned char sha1[20];
 737         char *url;
 738         struct buffer buffer;
 739         char *data;
 740         int i = 0;
 741
 742         struct active_request_slot *slot;
 743
 744         if (repo->got_indices)
 745                 return 0;
 746
 747         data = xmalloc(4096);
 748         buffer.size = 4096;
 749         buffer.posn = 0;
 750         buffer.buffer = data;
 751
 752         if (get_verbosely)
 753                 fprintf(stderr, "Getting pack list\n");
 754
 755         url = xmalloc(strlen(repo->base) + 21);
 756         sprintf(url, "%s/objects/info/packs", repo->base);
 757
 758         slot = get_active_slot();
 759         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 760         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 761         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 762         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 763         if (start_active_slot(slot)) {
 764                 run_active_slot(slot);
 765                 if (slot->curl_result != CURLE_OK)
 766                         return error("%s", curl_errorstr);
 767         } else {
 768                 return error("Unable to start request");
 769         }
 770
 771         while (i < buffer.posn) {
 772                 switch (data[i]) {
 773                 case 'P':
 774                         i++;
 775                         if (i + 52 < buffer.posn &&
 776                             !strncmp(data + i, " pack-", 6) &&
 777                             !strncmp(data + i + 46, ".pack\n", 6)) {
 778                                 get_sha1_hex(data + i + 6, sha1);
 779                                 setup_index(repo, sha1);
 780                                 i += 51;
 781                                 break;
 782                         }
 783                 default:
 784                         while (data[i] != '\n')
 785                                 i++;
 786                 }
 787                 i++;
 788         }
 789
 790         repo->got_indices = 1;
 791         return 0;
 792 }
 793
 794 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 795 {
 796         char *url;
 797         struct packed_git *target;
 798         struct packed_git **lst;
 799         FILE *packfile;
 800         char *filename;
 801         char tmpfile[PATH_MAX];
 802         int ret;
 803         long prev_posn = 0;
 804         char range[RANGE_HEADER_SIZE];
 805         struct curl_slist *range_header = NULL;
 806
 807         struct active_request_slot *slot;
 808
 809         if (fetch_indices(repo))
 810                 return -1;
 811         target = find_sha1_pack(sha1, repo->packs);
 812         if (!target)
 813                 return -1;
 814
 815         if (get_verbosely) {
 816                 fprintf(stderr, "Getting pack %s\n",
 817                         sha1_to_hex(target->sha1));
 818                 fprintf(stderr, " which contains %s\n",
 819                         sha1_to_hex(sha1));
 820         }
 821
 822         url = xmalloc(strlen(repo->base) + 65);
 823         sprintf(url, "%s/objects/pack/pack-%s.pack",
 824                 repo->base, sha1_to_hex(target->sha1));
 825
 826         filename = sha1_pack_name(target->sha1);
 827         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 828         packfile = fopen(tmpfile, "a");
 829         if (!packfile)
 830                 return error("Unable to open local file %s for pack",
 831                              filename);
 832
 833         slot = get_active_slot();
 834         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 835         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 836         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 837         slot->local = packfile;
 838
 839         /* If there is data present from a previous transfer attempt,
 840            resume where it left off */
 841         prev_posn = ftell(packfile);
 842         if (prev_posn>0) {
 843                 if (get_verbosely)
 844                         fprintf(stderr,
 845                                 "Resuming fetch of pack %s at byte %ld\n",
 846                                 sha1_to_hex(target->sha1), prev_posn);
 847                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 848                 range_header = curl_slist_append(range_header, range);
 849                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 850         }
 851
 852         if (start_active_slot(slot)) {
 853                 run_active_slot(slot);
 854                 if (slot->curl_result != CURLE_OK) {
 855                         fclose(packfile);
 856                         return error("Unable to get pack file %s\n%s", url,
 857                                      curl_errorstr);
 858                 }
 859         } else {
 860                 return error("Unable to start request");
 861         }
 862
 863         fclose(packfile);
 864
 865         ret = relink_or_rename(tmpfile, filename);
 866         if (ret)
 867                 return error("unable to write pack filename %s: %s",
 868                              filename, strerror(ret));
 869
 870         lst = &repo->packs;
 871         while (*lst != target)
 872                 lst = &((*lst)->next);
 873         *lst = (*lst)->next;
 874
 875         if (verify_pack(target, 0))
 876                 return -1;
 877         install_packed_git(target);
 878
 879         return 0;
 880 }
 881
 882 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 883 {
 884         char *hex = sha1_to_hex(sha1);
 885         int ret;
 886         struct transfer_request *request = request_queue_head;
 887
 888         while (request != NULL && memcmp(request->sha1, sha1, 20))
 889                 request = request->next;
 890         if (request == NULL)
 891                 return error("Couldn't find request for %s in the queue", hex);
 892
 893 #ifdef USE_CURL_MULTI
 894         int num_transfers;
 895         while (request->state == WAITING) {
 896                 curl_multi_perform(curlm, &num_transfers);
 897                 if (num_transfers < active_requests) {
 898                         process_curl_messages();
 899                         process_request_queue();
 900                 }
 901         }
 902 #else
 903         start_request(request);
 904 #endif
 905
 906         while (request->state == ACTIVE) {
 907                 run_active_slot(request->slot);
 908 #ifndef USE_CURL_MULTI
 909                 request->curl_result = request->slot->curl_result;
 910                 curl_easy_getinfo(request->slot->curl,
 911                                   CURLINFO_HTTP_CODE,
 912                                   &request->http_code);
 913                 request->slot = NULL;
 914
 915                 /* Use alternates if necessary */
 916                 if (request->http_code == 404 &&
 917                     request->repo->next != NULL) {
 918                         request->repo = request->repo->next;
 919                         start_request(request);
 920                 } else {
 921                         finish_request(request);
 922                         request->state = COMPLETE;
 923                 }
 924 #endif
 925         }
 926
 927         if (request->state == ABORTED) {
 928                 release_request(request);
 929                 return error("Request for %s aborted", hex);
 930         }
 931
 932         if (request->curl_result != CURLE_OK && request->http_code != 416) {
 933                 ret = error("%s", request->errorstr);
 934                 release_request(request);
 935                 return ret;
 936         }
 937
 938         if (request->zret != Z_STREAM_END) {
 939                 ret = error("File %s (%s) corrupt\n", hex, request->url);
 940                 release_request(request);
 941                 return ret;
 942         }
 943
 944         if (memcmp(request->sha1, request->real_sha1, 20)) {
 945                 release_request(request);
 946                 return error("File %s has bad hash\n", hex);
 947         }
 948
 949         if (request->rename < 0) {
 950                 ret = error("unable to write sha1 filename %s: %s",
 951                             request->filename,
 952                             strerror(request->rename));
 953                 release_request(request);
 954                 return ret;
 955         }
 956
 957         release_request(request);
 958         return 0;
 959 }
 960
 961 int fetch(unsigned char *sha1)
 962 {
 963         struct alt_base *altbase = alt;
 964
 965         if (!fetch_object(altbase, sha1))
 966                 return 0;
 967         while (altbase) {
 968                 if (!fetch_pack(altbase, sha1))
 969                         return 0;
 970                 altbase = altbase->next;
 971         }
 972         return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
 973                      alt->base);
 974 }
 975
 976 int fetch_ref(char *ref, unsigned char *sha1)
 977 {
 978         char *url, *posn;
 979         char hex[42];
 980         struct buffer buffer;
 981         char *base = alt->base;
 982         struct active_request_slot *slot;
 983         buffer.size = 41;
 984         buffer.posn = 0;
 985         buffer.buffer = hex;
 986         hex[41] = '\0';
 987
 988         url = xmalloc(strlen(base) + 6 + strlen(ref));
 989         strcpy(url, base);
 990         posn = url + strlen(base);
 991         strcpy(posn, "refs/");
 992         posn += 5;
 993         strcpy(posn, ref);
 994
 995         slot = get_active_slot();
 996         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 997         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 998         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 999         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1000         if (start_active_slot(slot)) {
1001                 run_active_slot(slot);
1002                 if (slot->curl_result != CURLE_OK)
1003                         return error("Couldn't get %s for %s\n%s",
1004                                      url, ref, curl_errorstr);
1005         } else {
1006                 return error("Unable to start request");
1007         }
1008
1009         hex[40] = '\0';
1010         get_sha1_hex(hex, sha1);
1011         return 0;
1012 }
1013
1014 int main(int argc, char **argv)
1015 {
1016         char *commit_id;
1017         char *url;
1018         int arg = 1;
1019         struct active_request_slot *slot;
1020
1021         while (arg < argc && argv[arg][0] == '-') {
1022                 if (argv[arg][1] == 't') {
1023                         get_tree = 1;
1024                 } else if (argv[arg][1] == 'c') {
1025                         get_history = 1;
1026                 } else if (argv[arg][1] == 'a') {
1027                         get_all = 1;
1028                         get_tree = 1;
1029                         get_history = 1;
1030                 } else if (argv[arg][1] == 'v') {
1031                         get_verbosely = 1;
1032                 } else if (argv[arg][1] == 'w') {
1033                         write_ref = argv[arg + 1];
1034                         arg++;
1035                 } else if (!strcmp(argv[arg], "--recover")) {
1036                         get_recover = 1;
1037                 }
1038                 arg++;
1039         }
1040         if (argc < arg + 2) {
1041                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1042                 return 1;
1043         }
1044         commit_id = argv[arg];
1045         url = argv[arg + 1];
1046
1047         curl_global_init(CURL_GLOBAL_ALL);
1048
1049 #ifdef USE_CURL_MULTI
1050         char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1051         if (http_max_requests != NULL)
1052                 max_requests = atoi(http_max_requests);
1053         if (max_requests < 1)
1054                 max_requests = DEFAULT_MAX_REQUESTS;
1055
1056         curlm = curl_multi_init();
1057         if (curlm == NULL) {
1058                 fprintf(stderr, "Error creating curl multi handle.\n");
1059                 return 1;
1060         }
1061 #endif
1062         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1063         no_range_header = curl_slist_append(no_range_header, "Range:");
1064
1065         curl_default = curl_easy_init();
1066
1067         curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
1068         curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1069 #if LIBCURL_VERSION_NUM >= 0x070907
1070         curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1071 #endif
1072
1073         if ((ssl_cert = getenv("GIT_SSL_CERT")) != NULL) {
1074                 curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1075         }
1076 #if LIBCURL_VERSION_NUM >= 0x070902
1077         if ((ssl_key = getenv("GIT_SSL_KEY")) != NULL) {
1078                 curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1079         }
1080 #endif
1081 #if LIBCURL_VERSION_NUM >= 0x070908
1082         if ((ssl_capath = getenv("GIT_SSL_CAPATH")) != NULL) {
1083                 curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1084         }
1085 #endif
1086         if ((ssl_cainfo = getenv("GIT_SSL_CAINFO")) != NULL) {
1087                 curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1088         }
1089         curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1090
1091         alt = xmalloc(sizeof(*alt));
1092         alt->base = url;
1093         alt->got_indices = 0;
1094         alt->packs = NULL;
1095         alt->next = NULL;
1096         fetch_alternates(alt->base);
1097
1098         if (pull(commit_id))
1099                 return 1;
1100
1101         curl_slist_free_all(no_pragma_header);
1102         curl_slist_free_all(no_range_header);
1103         curl_easy_cleanup(curl_default);
1104         slot = active_queue_head;
1105         while (slot != NULL) {
1106                 curl_easy_cleanup(slot->curl);
1107                 slot = slot->next;
1108         }
1109 #ifdef USE_CURL_MULTI
1110         curl_multi_cleanup(curlm);
1111 #endif
1112         curl_global_cleanup();
1113         return 0;
1114 }