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                         if (has_sha1_file(request->sha1))
 493                                 release_request(request);
 494                         else
 495                                 start_request(request);
 496                         curl_multi_perform(curlm, &num_transfers);
 497                 }
 498                 request = request->next;
 499         }
 500 }
 501 #endif
 502
 503 void prefetch(unsigned char *sha1)
 504 {
 505         struct transfer_request *newreq;
 506         struct transfer_request *tail;
 507         char *filename = sha1_file_name(sha1);
 508
 509         newreq = xmalloc(sizeof(*newreq));
 510         memcpy(newreq->sha1, sha1, 20);
 511         newreq->repo = alt;
 512         newreq->url = NULL;
 513         newreq->local = -1;
 514         newreq->state = WAITING;
 515         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 516         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 517                  "%s.temp", filename);
 518         newreq->next = NULL;
 519
 520         if (request_queue_head == NULL) {
 521                 request_queue_head = newreq;
 522         } else {
 523                 tail = request_queue_head;
 524                 while (tail->next != NULL) {
 525                         tail = tail->next;
 526                 }
 527                 tail->next = newreq;
 528         }
 529 #ifdef USE_CURL_MULTI
 530         process_request_queue();
 531         process_curl_messages();
 532 #endif
 533 }
 534
 535 static int got_alternates = 0;
 536
 537 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 538 {
 539         char *hex = sha1_to_hex(sha1);
 540         char *filename;
 541         char *url;
 542         char tmpfile[PATH_MAX];
 543         int ret;
 544         long prev_posn = 0;
 545         char range[RANGE_HEADER_SIZE];
 546         struct curl_slist *range_header = NULL;
 547
 548         FILE *indexfile;
 549         struct active_request_slot *slot;
 550
 551         if (has_pack_index(sha1))
 552                 return 0;
 553
 554         if (get_verbosely)
 555                 fprintf(stderr, "Getting index for pack %s\n", hex);
 556
 557         url = xmalloc(strlen(repo->base) + 64);
 558         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 559
 560         filename = sha1_pack_index_name(sha1);
 561         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 562         indexfile = fopen(tmpfile, "a");
 563         if (!indexfile)
 564                 return error("Unable to open local file %s for pack index",
 565                              filename);
 566
 567         slot = get_active_slot();
 568         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 569         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 570         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 571         slot->local = indexfile;
 572
 573         /* If there is data present from a previous transfer attempt,
 574            resume where it left off */
 575         prev_posn = ftell(indexfile);
 576         if (prev_posn>0) {
 577                 if (get_verbosely)
 578                         fprintf(stderr,
 579                                 "Resuming fetch of index for pack %s at byte %ld\n",
 580                                 hex, prev_posn);
 581                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 582                 range_header = curl_slist_append(range_header, range);
 583                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 584         }
 585
 586         if (start_active_slot(slot)) {
 587                 run_active_slot(slot);
 588                 if (slot->curl_result != CURLE_OK) {
 589                         fclose(indexfile);
 590                         return error("Unable to get pack index %s\n%s", url,
 591                                      curl_errorstr);
 592                 }
 593         } else {
 594                 return error("Unable to start request");
 595         }
 596
 597         fclose(indexfile);
 598
 599         ret = relink_or_rename(tmpfile, filename);
 600         if (ret)
 601                 return error("unable to write index filename %s: %s",
 602                              filename, strerror(ret));
 603
 604         return 0;
 605 }
 606
 607 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 608 {
 609         struct packed_git *new_pack;
 610         if (has_pack_file(sha1))
 611                 return 0; // don't list this as something we can get
 612
 613         if (fetch_index(repo, sha1))
 614                 return -1;
 615
 616         new_pack = parse_pack_index(sha1);
 617         new_pack->next = repo->packs;
 618         repo->packs = new_pack;
 619         return 0;
 620 }
 621
 622 static int fetch_alternates(char *base)
 623 {
 624         int ret = 0;
 625         struct buffer buffer;
 626         char *url;
 627         char *data;
 628         int i = 0;
 629         int http_specific = 1;
 630         struct alt_base *tail = alt;
 631
 632         struct active_request_slot *slot;
 633         if (got_alternates)
 634                 return 0;
 635         data = xmalloc(4096);
 636         buffer.size = 4095;
 637         buffer.posn = 0;
 638         buffer.buffer = data;
 639
 640         if (get_verbosely)
 641                 fprintf(stderr, "Getting alternates list\n");
 642
 643         url = xmalloc(strlen(base) + 31);
 644         sprintf(url, "%s/objects/info/http-alternates", base);
 645
 646         slot = get_active_slot();
 647         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 648         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 649         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 650         if (start_active_slot(slot)) {
 651                 run_active_slot(slot);
 652                 if (slot->curl_result != CURLE_OK || !buffer.posn) {
 653                         http_specific = 0;
 654
 655                         sprintf(url, "%s/objects/info/alternates", base);
 656
 657                         slot = get_active_slot();
 658                         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 659                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 660                                          fwrite_buffer);
 661                         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 662                         if (start_active_slot(slot)) {
 663                                 run_active_slot(slot);
 664                                 if (slot->curl_result != CURLE_OK) {
 665                                         return 0;
 666                                 }
 667                         }
 668                 }
 669         } else {
 670                 return 0;
 671         }
 672
 673         data[buffer.posn] = '\0';
 674
 675         while (i < buffer.posn) {
 676                 int posn = i;
 677                 while (posn < buffer.posn && data[posn] != '\n')
 678                         posn++;
 679                 if (data[posn] == '\n') {
 680                         int okay = 0;
 681                         int serverlen = 0;
 682                         struct alt_base *newalt;
 683                         char *target = NULL;
 684                         if (data[i] == '/') {
 685                                 serverlen = strchr(base + 8, '/') - base;
 686                                 okay = 1;
 687                         } else if (!memcmp(data + i, "../", 3)) {
 688                                 i += 3;
 689                                 serverlen = strlen(base);
 690                                 while (i + 2 < posn &&
 691                                        !memcmp(data + i, "../", 3)) {
 692                                         do {
 693                                                 serverlen--;
 694                                         } while (serverlen &&
 695                                                  base[serverlen - 1] != '/');
 696                                         i += 3;
 697                                 }
 698                                 // If the server got removed, give up.
 699                                 okay = strchr(base, ':') - base + 3 <
 700                                         serverlen;
 701                         } else if (http_specific) {
 702                                 char *colon = strchr(data + i, ':');
 703                                 char *slash = strchr(data + i, '/');
 704                                 if (colon && slash && colon < data + posn &&
 705                                     slash < data + posn && colon < slash) {
 706                                         okay = 1;
 707                                 }
 708                         }
 709                         // skip 'objects' at end
 710                         if (okay) {
 711                                 target = xmalloc(serverlen + posn - i - 6);
 712                                 strncpy(target, base, serverlen);
 713                                 strncpy(target + serverlen, data + i,
 714                                         posn - i - 7);
 715                                 target[serverlen + posn - i - 7] = '\0';
 716                                 if (get_verbosely)
 717                                         fprintf(stderr,
 718                                                 "Also look at %s\n", target);
 719                                 newalt = xmalloc(sizeof(*newalt));
 720                                 newalt->next = NULL;
 721                                 newalt->base = target;
 722                                 newalt->got_indices = 0;
 723                                 newalt->packs = NULL;
 724                                 while (tail->next != NULL)
 725                                         tail = tail->next;
 726                                 tail->next = newalt;
 727                                 ret++;
 728                         }
 729                 }
 730                 i = posn + 1;
 731         }
 732         got_alternates = 1;
 733
 734         return ret;
 735 }
 736
 737 static int fetch_indices(struct alt_base *repo)
 738 {
 739         unsigned char sha1[20];
 740         char *url;
 741         struct buffer buffer;
 742         char *data;
 743         int i = 0;
 744
 745         struct active_request_slot *slot;
 746
 747         if (repo->got_indices)
 748                 return 0;
 749
 750         data = xmalloc(4096);
 751         buffer.size = 4096;
 752         buffer.posn = 0;
 753         buffer.buffer = data;
 754
 755         if (get_verbosely)
 756                 fprintf(stderr, "Getting pack list\n");
 757
 758         url = xmalloc(strlen(repo->base) + 21);
 759         sprintf(url, "%s/objects/info/packs", repo->base);
 760
 761         slot = get_active_slot();
 762         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 763         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 764         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 765         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 766         if (start_active_slot(slot)) {
 767                 run_active_slot(slot);
 768                 if (slot->curl_result != CURLE_OK)
 769                         return error("%s", curl_errorstr);
 770         } else {
 771                 return error("Unable to start request");
 772         }
 773
 774         while (i < buffer.posn) {
 775                 switch (data[i]) {
 776                 case 'P':
 777                         i++;
 778                         if (i + 52 < buffer.posn &&
 779                             !strncmp(data + i, " pack-", 6) &&
 780                             !strncmp(data + i + 46, ".pack\n", 6)) {
 781                                 get_sha1_hex(data + i + 6, sha1);
 782                                 setup_index(repo, sha1);
 783                                 i += 51;
 784                                 break;
 785                         }
 786                 default:
 787                         while (data[i] != '\n')
 788                                 i++;
 789                 }
 790                 i++;
 791         }
 792
 793         repo->got_indices = 1;
 794         return 0;
 795 }
 796
 797 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 798 {
 799         char *url;
 800         struct packed_git *target;
 801         struct packed_git **lst;
 802         FILE *packfile;
 803         char *filename;
 804         char tmpfile[PATH_MAX];
 805         int ret;
 806         long prev_posn = 0;
 807         char range[RANGE_HEADER_SIZE];
 808         struct curl_slist *range_header = NULL;
 809
 810         struct active_request_slot *slot;
 811
 812         if (fetch_indices(repo))
 813                 return -1;
 814         target = find_sha1_pack(sha1, repo->packs);
 815         if (!target)
 816                 return -1;
 817
 818         if (get_verbosely) {
 819                 fprintf(stderr, "Getting pack %s\n",
 820                         sha1_to_hex(target->sha1));
 821                 fprintf(stderr, " which contains %s\n",
 822                         sha1_to_hex(sha1));
 823         }
 824
 825         url = xmalloc(strlen(repo->base) + 65);
 826         sprintf(url, "%s/objects/pack/pack-%s.pack",
 827                 repo->base, sha1_to_hex(target->sha1));
 828
 829         filename = sha1_pack_name(target->sha1);
 830         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 831         packfile = fopen(tmpfile, "a");
 832         if (!packfile)
 833                 return error("Unable to open local file %s for pack",
 834                              filename);
 835
 836         slot = get_active_slot();
 837         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 838         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 839         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 840         slot->local = packfile;
 841
 842         /* If there is data present from a previous transfer attempt,
 843            resume where it left off */
 844         prev_posn = ftell(packfile);
 845         if (prev_posn>0) {
 846                 if (get_verbosely)
 847                         fprintf(stderr,
 848                                 "Resuming fetch of pack %s at byte %ld\n",
 849                                 sha1_to_hex(target->sha1), prev_posn);
 850                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 851                 range_header = curl_slist_append(range_header, range);
 852                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 853         }
 854
 855         if (start_active_slot(slot)) {
 856                 run_active_slot(slot);
 857                 if (slot->curl_result != CURLE_OK) {
 858                         fclose(packfile);
 859                         return error("Unable to get pack file %s\n%s", url,
 860                                      curl_errorstr);
 861                 }
 862         } else {
 863                 return error("Unable to start request");
 864         }
 865
 866         fclose(packfile);
 867
 868         ret = relink_or_rename(tmpfile, filename);
 869         if (ret)
 870                 return error("unable to write pack filename %s: %s",
 871                              filename, strerror(ret));
 872
 873         lst = &repo->packs;
 874         while (*lst != target)
 875                 lst = &((*lst)->next);
 876         *lst = (*lst)->next;
 877
 878         if (verify_pack(target, 0))
 879                 return -1;
 880         install_packed_git(target);
 881
 882         return 0;
 883 }
 884
 885 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 886 {
 887         char *hex = sha1_to_hex(sha1);
 888         int ret;
 889         struct transfer_request *request = request_queue_head;
 890
 891         while (request != NULL && memcmp(request->sha1, sha1, 20))
 892                 request = request->next;
 893         if (request == NULL)
 894                 return error("Couldn't find request for %s in the queue", hex);
 895
 896         if (has_sha1_file(request->sha1)) {
 897                 release_request(request);
 898                 return 0;
 899         }
 900
 901 #ifdef USE_CURL_MULTI
 902         int num_transfers;
 903         while (request->state == WAITING) {
 904                 curl_multi_perform(curlm, &num_transfers);
 905                 if (num_transfers < active_requests) {
 906                         process_curl_messages();
 907                         process_request_queue();
 908                 }
 909         }
 910 #else
 911         start_request(request);
 912 #endif
 913
 914         while (request->state == ACTIVE) {
 915                 run_active_slot(request->slot);
 916 #ifndef USE_CURL_MULTI
 917                 request->curl_result = request->slot->curl_result;
 918                 curl_easy_getinfo(request->slot->curl,
 919                                   CURLINFO_HTTP_CODE,
 920                                   &request->http_code);
 921                 request->slot = NULL;
 922
 923                 /* Use alternates if necessary */
 924                 if (request->http_code == 404 &&
 925                     request->repo->next != NULL) {
 926                         request->repo = request->repo->next;
 927                         start_request(request);
 928                 } else {
 929                         finish_request(request);
 930                         request->state = COMPLETE;
 931                 }
 932 #endif
 933         }
 934
 935         if (request->state == ABORTED) {
 936                 release_request(request);
 937                 return error("Request for %s aborted", hex);
 938         }
 939
 940         if (request->curl_result != CURLE_OK && request->http_code != 416) {
 941                 ret = error("%s", request->errorstr);
 942                 release_request(request);
 943                 return ret;
 944         }
 945
 946         if (request->zret != Z_STREAM_END) {
 947                 ret = error("File %s (%s) corrupt\n", hex, request->url);
 948                 release_request(request);
 949                 return ret;
 950         }
 951
 952         if (memcmp(request->sha1, request->real_sha1, 20)) {
 953                 release_request(request);
 954                 return error("File %s has bad hash\n", hex);
 955         }
 956
 957         if (request->rename < 0) {
 958                 ret = error("unable to write sha1 filename %s: %s",
 959                             request->filename,
 960                             strerror(request->rename));
 961                 release_request(request);
 962                 return ret;
 963         }
 964
 965         release_request(request);
 966         return 0;
 967 }
 968
 969 int fetch(unsigned char *sha1)
 970 {
 971         struct alt_base *altbase = alt;
 972
 973         if (!fetch_object(altbase, sha1))
 974                 return 0;
 975         while (altbase) {
 976                 if (!fetch_pack(altbase, sha1))
 977                         return 0;
 978                 altbase = altbase->next;
 979         }
 980         return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
 981                      alt->base);
 982 }
 983
 984 int fetch_ref(char *ref, unsigned char *sha1)
 985 {
 986         char *url, *posn;
 987         char hex[42];
 988         struct buffer buffer;
 989         char *base = alt->base;
 990         struct active_request_slot *slot;
 991         buffer.size = 41;
 992         buffer.posn = 0;
 993         buffer.buffer = hex;
 994         hex[41] = '\0';
 995
 996         url = xmalloc(strlen(base) + 6 + strlen(ref));
 997         strcpy(url, base);
 998         posn = url + strlen(base);
 999         strcpy(posn, "refs/");
1000         posn += 5;
1001         strcpy(posn, ref);
1002
1003         slot = get_active_slot();
1004         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
1005         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
1006         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
1007         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1008         if (start_active_slot(slot)) {
1009                 run_active_slot(slot);
1010                 if (slot->curl_result != CURLE_OK)
1011                         return error("Couldn't get %s for %s\n%s",
1012                                      url, ref, curl_errorstr);
1013         } else {
1014                 return error("Unable to start request");
1015         }
1016
1017         hex[40] = '\0';
1018         get_sha1_hex(hex, sha1);
1019         return 0;
1020 }
1021
1022 int main(int argc, char **argv)
1023 {
1024         char *commit_id;
1025         char *url;
1026         int arg = 1;
1027         struct active_request_slot *slot;
1028
1029         while (arg < argc && argv[arg][0] == '-') {
1030                 if (argv[arg][1] == 't') {
1031                         get_tree = 1;
1032                 } else if (argv[arg][1] == 'c') {
1033                         get_history = 1;
1034                 } else if (argv[arg][1] == 'a') {
1035                         get_all = 1;
1036                         get_tree = 1;
1037                         get_history = 1;
1038                 } else if (argv[arg][1] == 'v') {
1039                         get_verbosely = 1;
1040                 } else if (argv[arg][1] == 'w') {
1041                         write_ref = argv[arg + 1];
1042                         arg++;
1043                 } else if (!strcmp(argv[arg], "--recover")) {
1044                         get_recover = 1;
1045                 }
1046                 arg++;
1047         }
1048         if (argc < arg + 2) {
1049                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1050                 return 1;
1051         }
1052         commit_id = argv[arg];
1053         url = argv[arg + 1];
1054
1055         curl_global_init(CURL_GLOBAL_ALL);
1056
1057 #ifdef USE_CURL_MULTI
1058         char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1059         if (http_max_requests != NULL)
1060                 max_requests = atoi(http_max_requests);
1061         if (max_requests < 1)
1062                 max_requests = DEFAULT_MAX_REQUESTS;
1063
1064         curlm = curl_multi_init();
1065         if (curlm == NULL) {
1066                 fprintf(stderr, "Error creating curl multi handle.\n");
1067                 return 1;
1068         }
1069 #endif
1070         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1071         no_range_header = curl_slist_append(no_range_header, "Range:");
1072
1073         curl_default = curl_easy_init();
1074
1075         curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
1076         curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1077 #if LIBCURL_VERSION_NUM >= 0x070907
1078         curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1079 #endif
1080
1081         if ((ssl_cert = getenv("GIT_SSL_CERT")) != NULL) {
1082                 curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1083         }
1084 #if LIBCURL_VERSION_NUM >= 0x070902
1085         if ((ssl_key = getenv("GIT_SSL_KEY")) != NULL) {
1086                 curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1087         }
1088 #endif
1089 #if LIBCURL_VERSION_NUM >= 0x070908
1090         if ((ssl_capath = getenv("GIT_SSL_CAPATH")) != NULL) {
1091                 curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1092         }
1093 #endif
1094         if ((ssl_cainfo = getenv("GIT_SSL_CAINFO")) != NULL) {
1095                 curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1096         }
1097         curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1098
1099         alt = xmalloc(sizeof(*alt));
1100         alt->base = url;
1101         alt->got_indices = 0;
1102         alt->packs = NULL;
1103         alt->next = NULL;
1104         fetch_alternates(alt->base);
1105
1106         if (pull(commit_id))
1107                 return 1;
1108
1109         curl_slist_free_all(no_pragma_header);
1110         curl_slist_free_all(no_range_header);
1111         curl_easy_cleanup(curl_default);
1112         slot = active_queue_head;
1113         while (slot != NULL) {
1114                 curl_easy_cleanup(slot->curl);
1115                 slot = slot->next;
1116         }
1117 #ifdef USE_CURL_MULTI
1118         curl_multi_cleanup(curlm);
1119 #endif
1120         curl_global_cleanup();
1121         return 0;
1122 }