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 = -1;
  29 static CURLM *curlm;
  30 #endif
  31 static CURL *curl_default;
  32 static struct curl_slist *pragma_header;
  33 static struct curl_slist *no_pragma_header;
  34 static struct curl_slist *no_range_header;
  35 static char curl_errorstr[CURL_ERROR_SIZE];
  36
  37 struct alt_base
  38 {
  39         char *base;
  40         int got_indices;
  41         struct packed_git *packs;
  42         struct alt_base *next;
  43 };
  44
  45 static struct alt_base *alt = NULL;
  46
  47 enum transfer_state {
  48         WAITING,
  49         ABORTED,
  50         ACTIVE,
  51         COMPLETE,
  52 };
  53
  54 struct transfer_request
  55 {
  56         unsigned char sha1[20];
  57         struct alt_base *repo;
  58         char *url;
  59         char filename[PATH_MAX];
  60         char tmpfile[PATH_MAX];
  61         int local;
  62         enum transfer_state state;
  63         CURLcode curl_result;
  64         char errorstr[CURL_ERROR_SIZE];
  65         long http_code;
  66         unsigned char real_sha1[20];
  67         SHA_CTX c;
  68         z_stream stream;
  69         int zret;
  70         int rename;
  71         struct active_request_slot *slot;
  72         struct transfer_request *next;
  73 };
  74
  75 struct active_request_slot
  76 {
  77         CURL *curl;
  78         FILE *local;
  79         int in_use;
  80         int done;
  81         CURLcode curl_result;
  82         struct active_request_slot *next;
  83 };
  84
  85 static struct transfer_request *request_queue_head = NULL;
  86 static struct active_request_slot *active_queue_head = NULL;
  87
  88 static int curl_ssl_verify = -1;
  89 static char *ssl_cert = NULL;
  90 static char *ssl_key = NULL;
  91 static char *ssl_capath = NULL;
  92 static char *ssl_cainfo = NULL;
  93
  94 struct buffer
  95 {
  96         size_t posn;
  97         size_t size;
  98         void *buffer;
  99 };
 100
 101 static int http_options(const char *var, const char *value)
 102 {
 103         if (!strcmp("http.sslverify", var)) {
 104                 if (curl_ssl_verify == -1) {
 105                         curl_ssl_verify = git_config_bool(var, value);
 106                 }
 107                 return 0;
 108         }
 109
 110         if (!strcmp("http.sslcert", var)) {
 111                 if (ssl_cert == NULL) {
 112                         ssl_cert = xmalloc(strlen(value)+1);
 113                         strcpy(ssl_cert, value);
 114                 }
 115                 return 0;
 116         }
 117 #if LIBCURL_VERSION_NUM >= 0x070902
 118         if (!strcmp("http.sslkey", var)) {
 119                 if (ssl_key == NULL) {
 120                         ssl_key = xmalloc(strlen(value)+1);
 121                         strcpy(ssl_key, value);
 122                 }
 123                 return 0;
 124         }
 125 #endif
 126 #if LIBCURL_VERSION_NUM >= 0x070908
 127         if (!strcmp("http.sslcapath", var)) {
 128                 if (ssl_capath == NULL) {
 129                         ssl_capath = xmalloc(strlen(value)+1);
 130                         strcpy(ssl_capath, value);
 131                 }
 132                 return 0;
 133         }
 134 #endif
 135         if (!strcmp("http.sslcainfo", var)) {
 136                 if (ssl_cainfo == NULL) {
 137                         ssl_cainfo = xmalloc(strlen(value)+1);
 138                         strcpy(ssl_cainfo, value);
 139                 }
 140                 return 0;
 141         }
 142
 143 #ifdef USE_CURL_MULTI
 144         if (!strcmp("http.maxrequests", var)) {
 145                 if (max_requests == -1)
 146                         max_requests = git_config_int(var, value);
 147                 return 0;
 148         }
 149 #endif
 150
 151         /* Fall back on the default ones */
 152         return git_default_config(var, value);
 153 }
 154
 155 static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
 156                             struct buffer *buffer)
 157 {
 158         size_t size = eltsize * nmemb;
 159         if (size > buffer->size - buffer->posn)
 160                 size = buffer->size - buffer->posn;
 161         memcpy(buffer->buffer + buffer->posn, ptr, size);
 162         buffer->posn += size;
 163         data_received++;
 164         return size;
 165 }
 166
 167 static size_t fwrite_buffer_dynamic(const void *ptr, size_t eltsize,
 168                                     size_t nmemb, struct buffer *buffer)
 169 {
 170         size_t size = eltsize * nmemb;
 171         if (size > buffer->size - buffer->posn) {
 172                 buffer->size = buffer->size * 3 / 2;
 173                 if (buffer->size < buffer->posn + size)
 174                         buffer->size = buffer->posn + size;
 175                 buffer->buffer = xrealloc(buffer->buffer, buffer->size);
 176         }
 177         memcpy(buffer->buffer + buffer->posn, ptr, size);
 178         buffer->posn += size;
 179         data_received++;
 180         return size;
 181 }
 182
 183 static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 184                                void *data)
 185 {
 186         unsigned char expn[4096];
 187         size_t size = eltsize * nmemb;
 188         int posn = 0;
 189         struct transfer_request *request = (struct transfer_request *)data;
 190         do {
 191                 ssize_t retval = write(request->local,
 192                                        ptr + posn, size - posn);
 193                 if (retval < 0)
 194                         return posn;
 195                 posn += retval;
 196         } while (posn < size);
 197
 198         request->stream.avail_in = size;
 199         request->stream.next_in = ptr;
 200         do {
 201                 request->stream.next_out = expn;
 202                 request->stream.avail_out = sizeof(expn);
 203                 request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
 204                 SHA1_Update(&request->c, expn,
 205                             sizeof(expn) - request->stream.avail_out);
 206         } while (request->stream.avail_in && request->zret == Z_OK);
 207         data_received++;
 208         return size;
 209 }
 210
 211 #ifdef USE_CURL_MULTI
 212 void process_curl_messages();
 213 void process_request_queue();
 214 #endif
 215
 216 struct active_request_slot *get_active_slot()
 217 {
 218         struct active_request_slot *slot = active_queue_head;
 219         struct active_request_slot *newslot;
 220
 221 #ifdef USE_CURL_MULTI
 222         int num_transfers;
 223
 224         /* Wait for a slot to open up if the queue is full */
 225         while (active_requests >= max_requests) {
 226                 curl_multi_perform(curlm, &num_transfers);
 227                 if (num_transfers < active_requests) {
 228                         process_curl_messages();
 229                 }
 230         }
 231 #endif
 232
 233         while (slot != NULL && slot->in_use) {
 234                 slot = slot->next;
 235         }
 236         if (slot == NULL) {
 237                 newslot = xmalloc(sizeof(*newslot));
 238                 newslot->curl = curl_easy_duphandle(curl_default);
 239                 newslot->in_use = 0;
 240                 newslot->next = NULL;
 241
 242                 slot = active_queue_head;
 243                 if (slot == NULL) {
 244                         active_queue_head = newslot;
 245                 } else {
 246                         while (slot->next != NULL) {
 247                                 slot = slot->next;
 248                         }
 249                         slot->next = newslot;
 250                 }
 251                 slot = newslot;
 252         }
 253
 254         active_requests++;
 255         slot->in_use = 1;
 256         slot->done = 0;
 257         slot->local = NULL;
 258         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 259         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 260         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 261
 262         return slot;
 263 }
 264
 265 int start_active_slot(struct active_request_slot *slot)
 266 {
 267 #ifdef USE_CURL_MULTI
 268         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 269
 270         if (curlm_result != CURLM_OK &&
 271             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 272                 active_requests--;
 273                 slot->in_use = 0;
 274                 return 0;
 275         }
 276 #endif
 277         return 1;
 278 }
 279
 280 void run_active_slot(struct active_request_slot *slot)
 281 {
 282 #ifdef USE_CURL_MULTI
 283         int num_transfers;
 284         long last_pos = 0;
 285         long current_pos;
 286         fd_set readfds;
 287         fd_set writefds;
 288         fd_set excfds;
 289         int max_fd;
 290         struct timeval select_timeout;
 291         CURLMcode curlm_result;
 292
 293         while (!slot->done) {
 294                 data_received = 0;
 295                 do {
 296                         curlm_result = curl_multi_perform(curlm,
 297                                                           &num_transfers);
 298                 } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 299                 if (num_transfers < active_requests) {
 300                         process_curl_messages();
 301                         process_request_queue();
 302                 }
 303
 304                 if (!data_received && slot->local != NULL) {
 305                         current_pos = ftell(slot->local);
 306                         if (current_pos > last_pos)
 307                                 data_received++;
 308                         last_pos = current_pos;
 309                 }
 310
 311                 if (!slot->done && !data_received) {
 312                         max_fd = 0;
 313                         FD_ZERO(&readfds);
 314                         FD_ZERO(&writefds);
 315                         FD_ZERO(&excfds);
 316                         select_timeout.tv_sec = 0;
 317                         select_timeout.tv_usec = 50000;
 318                         select(max_fd, &readfds, &writefds,
 319                                &excfds, &select_timeout);
 320                 }
 321         }
 322 #else
 323         slot->curl_result = curl_easy_perform(slot->curl);
 324         active_requests--;
 325 #endif
 326 }
 327
 328 void start_request(struct transfer_request *request)
 329 {
 330         char *hex = sha1_to_hex(request->sha1);
 331         char prevfile[PATH_MAX];
 332         char *url;
 333         char *posn;
 334         int prevlocal;
 335         unsigned char prev_buf[PREV_BUF_SIZE];
 336         ssize_t prev_read = 0;
 337         long prev_posn = 0;
 338         char range[RANGE_HEADER_SIZE];
 339         struct curl_slist *range_header = NULL;
 340         struct active_request_slot *slot;
 341
 342         snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 343         unlink(prevfile);
 344         rename(request->tmpfile, prevfile);
 345         unlink(request->tmpfile);
 346
 347         request->local = open(request->tmpfile,
 348                               O_WRONLY | O_CREAT | O_EXCL, 0666);
 349         /* This could have failed due to the "lazy directory creation";
 350          * try to mkdir the last path component.
 351          */
 352         if (request->local < 0 && errno == ENOENT) {
 353                 char *dir = strrchr(request->tmpfile, '/');
 354                 if (dir) {
 355                         *dir = 0;
 356                         mkdir(request->tmpfile, 0777);
 357                         *dir = '/';
 358                 }
 359                 request->local = open(request->tmpfile,
 360                                       O_WRONLY | O_CREAT | O_EXCL, 0666);
 361         }
 362
 363         if (request->local < 0) {
 364                 request->state = ABORTED;
 365                 error("Couldn't create temporary file %s for %s: %s\n",
 366                       request->tmpfile, request->filename, strerror(errno));
 367                 return;
 368         }
 369
 370         memset(&request->stream, 0, sizeof(request->stream));
 371
 372         inflateInit(&request->stream);
 373
 374         SHA1_Init(&request->c);
 375
 376         url = xmalloc(strlen(request->repo->base) + 50);
 377         request->url = xmalloc(strlen(request->repo->base) + 50);
 378         strcpy(url, request->repo->base);
 379         posn = url + strlen(request->repo->base);
 380         strcpy(posn, "objects/");
 381         posn += 8;
 382         memcpy(posn, hex, 2);
 383         posn += 2;
 384         *(posn++) = '/';
 385         strcpy(posn, hex + 2);
 386         strcpy(request->url, url);
 387
 388         /* If a previous temp file is present, process what was already
 389            fetched. */
 390         prevlocal = open(prevfile, O_RDONLY);
 391         if (prevlocal != -1) {
 392                 do {
 393                         prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 394                         if (prev_read>0) {
 395                                 if (fwrite_sha1_file(prev_buf,
 396                                                      1,
 397                                                      prev_read,
 398                                                      request) == prev_read) {
 399                                         prev_posn += prev_read;
 400                                 } else {
 401                                         prev_read = -1;
 402                                 }
 403                         }
 404                 } while (prev_read > 0);
 405                 close(prevlocal);
 406         }
 407         unlink(prevfile);
 408
 409         /* Reset inflate/SHA1 if there was an error reading the previous temp
 410            file; also rewind to the beginning of the local file. */
 411         if (prev_read == -1) {
 412                 memset(&request->stream, 0, sizeof(request->stream));
 413                 inflateInit(&request->stream);
 414                 SHA1_Init(&request->c);
 415                 if (prev_posn>0) {
 416                         prev_posn = 0;
 417                         lseek(request->local, SEEK_SET, 0);
 418                         ftruncate(request->local, 0);
 419                 }
 420         }
 421
 422         slot = get_active_slot();
 423         curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 424         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 425         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 426         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 427         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 428
 429         /* If we have successfully processed data from a previous fetch
 430            attempt, only fetch the data we don't already have. */
 431         if (prev_posn>0) {
 432                 if (get_verbosely)
 433                         fprintf(stderr,
 434                                 "Resuming fetch of object %s at byte %ld\n",
 435                                 hex, prev_posn);
 436                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 437                 range_header = curl_slist_append(range_header, range);
 438                 curl_easy_setopt(slot->curl,
 439                                  CURLOPT_HTTPHEADER, range_header);
 440         }
 441
 442         /* Try to get the request started, abort the request on error */
 443         if (!start_active_slot(slot)) {
 444                 request->state = ABORTED;
 445                 close(request->local);
 446                 free(request->url);
 447                 return;
 448         }
 449
 450         request->slot = slot;
 451         request->state = ACTIVE;
 452 }
 453
 454 void finish_request(struct transfer_request *request)
 455 {
 456         fchmod(request->local, 0444);
 457         close(request->local);
 458
 459         if (request->http_code == 416) {
 460                 fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 461         } else if (request->curl_result != CURLE_OK) {
 462                 return;
 463         }
 464
 465         inflateEnd(&request->stream);
 466         SHA1_Final(request->real_sha1, &request->c);
 467         if (request->zret != Z_STREAM_END) {
 468                 unlink(request->tmpfile);
 469                 return;
 470         }
 471         if (memcmp(request->sha1, request->real_sha1, 20)) {
 472                 unlink(request->tmpfile);
 473                 return;
 474         }
 475         request->rename =
 476                 move_temp_to_file(request->tmpfile, request->filename);
 477
 478         if (request->rename == 0)
 479                 pull_say("got %s\n", sha1_to_hex(request->sha1));
 480 }
 481
 482 void release_request(struct transfer_request *request)
 483 {
 484         struct transfer_request *entry = request_queue_head;
 485
 486         if (request == request_queue_head) {
 487                 request_queue_head = request->next;
 488         } else {
 489                 while (entry->next != NULL && entry->next != request)
 490                         entry = entry->next;
 491                 if (entry->next == request)
 492                         entry->next = entry->next->next;
 493         }
 494
 495         free(request->url);
 496         free(request);
 497 }
 498
 499 #ifdef USE_CURL_MULTI
 500 void process_curl_messages()
 501 {
 502         int num_messages;
 503         struct active_request_slot *slot;
 504         struct transfer_request *request = NULL;
 505         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 506
 507         while (curl_message != NULL) {
 508                 if (curl_message->msg == CURLMSG_DONE) {
 509                         slot = active_queue_head;
 510                         while (slot != NULL &&
 511                                slot->curl != curl_message->easy_handle)
 512                                 slot = slot->next;
 513                         if (slot != NULL) {
 514                                 curl_multi_remove_handle(curlm, slot->curl);
 515                                 active_requests--;
 516                                 slot->done = 1;
 517                                 slot->in_use = 0;
 518                                 slot->curl_result = curl_message->data.result;
 519                                 request = request_queue_head;
 520                                 while (request != NULL &&
 521                                        request->slot != slot)
 522                                         request = request->next;
 523                         } else {
 524                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 525                         }
 526                         if (request != NULL) {
 527                                 request->curl_result =
 528                                         curl_message->data.result;
 529                                 curl_easy_getinfo(slot->curl,
 530                                                   CURLINFO_HTTP_CODE,
 531                                                   &request->http_code);
 532                                 request->slot = NULL;
 533
 534                                 /* Use alternates if necessary */
 535                                 if (request->http_code == 404 &&
 536                                     request->repo->next != NULL) {
 537                                         request->repo = request->repo->next;
 538                                         start_request(request);
 539                                 } else {
 540                                         finish_request(request);
 541                                         request->state = COMPLETE;
 542                                 }
 543                         }
 544                 } else {
 545                         fprintf(stderr, "Unknown CURL message received: %d\n",
 546                                 (int)curl_message->msg);
 547                 }
 548                 curl_message = curl_multi_info_read(curlm, &num_messages);
 549         }
 550 }
 551
 552 void process_request_queue()
 553 {
 554         struct transfer_request *request = request_queue_head;
 555         int num_transfers;
 556
 557         while (active_requests < max_requests && request != NULL) {
 558                 if (request->state == WAITING) {
 559                         if (has_sha1_file(request->sha1))
 560                                 release_request(request);
 561                         else
 562                                 start_request(request);
 563                         curl_multi_perform(curlm, &num_transfers);
 564                 }
 565                 request = request->next;
 566         }
 567 }
 568 #endif
 569
 570 void prefetch(unsigned char *sha1)
 571 {
 572         struct transfer_request *newreq;
 573         struct transfer_request *tail;
 574         char *filename = sha1_file_name(sha1);
 575
 576         newreq = xmalloc(sizeof(*newreq));
 577         memcpy(newreq->sha1, sha1, 20);
 578         newreq->repo = alt;
 579         newreq->url = NULL;
 580         newreq->local = -1;
 581         newreq->state = WAITING;
 582         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 583         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 584                  "%s.temp", filename);
 585         newreq->next = NULL;
 586
 587         if (request_queue_head == NULL) {
 588                 request_queue_head = newreq;
 589         } else {
 590                 tail = request_queue_head;
 591                 while (tail->next != NULL) {
 592                         tail = tail->next;
 593                 }
 594                 tail->next = newreq;
 595         }
 596 #ifdef USE_CURL_MULTI
 597         process_request_queue();
 598         process_curl_messages();
 599 #endif
 600 }
 601
 602 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 603 {
 604         char *hex = sha1_to_hex(sha1);
 605         char *filename;
 606         char *url;
 607         char tmpfile[PATH_MAX];
 608         long prev_posn = 0;
 609         char range[RANGE_HEADER_SIZE];
 610         struct curl_slist *range_header = NULL;
 611
 612         FILE *indexfile;
 613         struct active_request_slot *slot;
 614
 615         if (has_pack_index(sha1))
 616                 return 0;
 617
 618         if (get_verbosely)
 619                 fprintf(stderr, "Getting index for pack %s\n", hex);
 620
 621         url = xmalloc(strlen(repo->base) + 64);
 622         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 623
 624         filename = sha1_pack_index_name(sha1);
 625         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 626         indexfile = fopen(tmpfile, "a");
 627         if (!indexfile)
 628                 return error("Unable to open local file %s for pack index",
 629                              filename);
 630
 631         slot = get_active_slot();
 632         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 633         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 634         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 635         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 636         slot->local = indexfile;
 637
 638         /* If there is data present from a previous transfer attempt,
 639            resume where it left off */
 640         prev_posn = ftell(indexfile);
 641         if (prev_posn>0) {
 642                 if (get_verbosely)
 643                         fprintf(stderr,
 644                                 "Resuming fetch of index for pack %s at byte %ld\n",
 645                                 hex, prev_posn);
 646                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 647                 range_header = curl_slist_append(range_header, range);
 648                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 649         }
 650
 651         if (start_active_slot(slot)) {
 652                 run_active_slot(slot);
 653                 if (slot->curl_result != CURLE_OK) {
 654                         fclose(indexfile);
 655                         return error("Unable to get pack index %s\n%s", url,
 656                                      curl_errorstr);
 657                 }
 658         } else {
 659                 return error("Unable to start request");
 660         }
 661
 662         fclose(indexfile);
 663
 664         return move_temp_to_file(tmpfile, filename);
 665 }
 666
 667 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 668 {
 669         struct packed_git *new_pack;
 670         if (has_pack_file(sha1))
 671                 return 0; // don't list this as something we can get
 672
 673         if (fetch_index(repo, sha1))
 674                 return -1;
 675
 676         new_pack = parse_pack_index(sha1);
 677         new_pack->next = repo->packs;
 678         repo->packs = new_pack;
 679         return 0;
 680 }
 681
 682 static int fetch_alternates(char *base)
 683 {
 684         int ret = 0;
 685         struct buffer buffer;
 686         char *url;
 687         char *data;
 688         int i = 0;
 689         int http_specific = 1;
 690         struct alt_base *tail = alt;
 691         static const char null_byte = '\0';
 692
 693         struct active_request_slot *slot;
 694
 695         data = xmalloc(4096);
 696         buffer.size = 4096;
 697         buffer.posn = 0;
 698         buffer.buffer = data;
 699
 700         if (get_verbosely)
 701                 fprintf(stderr, "Getting alternates list\n");
 702
 703         url = xmalloc(strlen(base) + 31);
 704         sprintf(url, "%s/objects/info/http-alternates", base);
 705
 706         slot = get_active_slot();
 707         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 708         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 709                          fwrite_buffer_dynamic);
 710         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 711         if (start_active_slot(slot)) {
 712                 run_active_slot(slot);
 713                 if (slot->curl_result != CURLE_OK || !buffer.posn) {
 714                         http_specific = 0;
 715
 716                         sprintf(url, "%s/objects/info/alternates", base);
 717
 718                         slot = get_active_slot();
 719                         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 720                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 721                                          fwrite_buffer_dynamic);
 722                         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 723                         if (start_active_slot(slot)) {
 724                                 run_active_slot(slot);
 725                                 if (slot->curl_result != CURLE_OK) {
 726                                         free(buffer.buffer);
 727                                         return 0;
 728                                 }
 729                         }
 730                 }
 731         } else {
 732                 free(buffer.buffer);
 733                 return 0;
 734         }
 735
 736         fwrite_buffer_dynamic(&null_byte, 1, 1, &buffer);
 737         buffer.posn--;
 738         data = buffer.buffer;
 739
 740         while (i < buffer.posn) {
 741                 int posn = i;
 742                 while (posn < buffer.posn && data[posn] != '\n')
 743                         posn++;
 744                 if (data[posn] == '\n') {
 745                         int okay = 0;
 746                         int serverlen = 0;
 747                         struct alt_base *newalt;
 748                         char *target = NULL;
 749                         if (data[i] == '/') {
 750                                 serverlen = strchr(base + 8, '/') - base;
 751                                 okay = 1;
 752                         } else if (!memcmp(data + i, "../", 3)) {
 753                                 i += 3;
 754                                 serverlen = strlen(base);
 755                                 while (i + 2 < posn &&
 756                                        !memcmp(data + i, "../", 3)) {
 757                                         do {
 758                                                 serverlen--;
 759                                         } while (serverlen &&
 760                                                  base[serverlen - 1] != '/');
 761                                         i += 3;
 762                                 }
 763                                 // If the server got removed, give up.
 764                                 okay = strchr(base, ':') - base + 3 <
 765                                         serverlen;
 766                         } else if (http_specific) {
 767                                 char *colon = strchr(data + i, ':');
 768                                 char *slash = strchr(data + i, '/');
 769                                 if (colon && slash && colon < data + posn &&
 770                                     slash < data + posn && colon < slash) {
 771                                         okay = 1;
 772                                 }
 773                         }
 774                         // skip 'objects' at end
 775                         if (okay) {
 776                                 target = xmalloc(serverlen + posn - i - 6);
 777                                 strncpy(target, base, serverlen);
 778                                 strncpy(target + serverlen, data + i,
 779                                         posn - i - 7);
 780                                 target[serverlen + posn - i - 7] = '\0';
 781                                 if (get_verbosely)
 782                                         fprintf(stderr,
 783                                                 "Also look at %s\n", target);
 784                                 newalt = xmalloc(sizeof(*newalt));
 785                                 newalt->next = NULL;
 786                                 newalt->base = target;
 787                                 newalt->got_indices = 0;
 788                                 newalt->packs = NULL;
 789                                 while (tail->next != NULL)
 790                                         tail = tail->next;
 791                                 tail->next = newalt;
 792                                 ret++;
 793                         }
 794                 }
 795                 i = posn + 1;
 796         }
 797
 798         free(buffer.buffer);
 799         return ret;
 800 }
 801
 802 static int fetch_indices(struct alt_base *repo)
 803 {
 804         unsigned char sha1[20];
 805         char *url;
 806         struct buffer buffer;
 807         char *data;
 808         int i = 0;
 809
 810         struct active_request_slot *slot;
 811
 812         if (repo->got_indices)
 813                 return 0;
 814
 815         data = xmalloc(4096);
 816         buffer.size = 4096;
 817         buffer.posn = 0;
 818         buffer.buffer = data;
 819
 820         if (get_verbosely)
 821                 fprintf(stderr, "Getting pack list\n");
 822
 823         url = xmalloc(strlen(repo->base) + 21);
 824         sprintf(url, "%s/objects/info/packs", repo->base);
 825
 826         slot = get_active_slot();
 827         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 828         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 829                          fwrite_buffer_dynamic);
 830         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 831         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 832         if (start_active_slot(slot)) {
 833                 run_active_slot(slot);
 834                 if (slot->curl_result != CURLE_OK) {
 835                         free(buffer.buffer);
 836                         return error("%s", curl_errorstr);
 837                 }
 838         } else {
 839                 free(buffer.buffer);
 840                 return error("Unable to start request");
 841         }
 842
 843         data = buffer.buffer;
 844         while (i < buffer.posn) {
 845                 switch (data[i]) {
 846                 case 'P':
 847                         i++;
 848                         if (i + 52 < buffer.posn &&
 849                             !strncmp(data + i, " pack-", 6) &&
 850                             !strncmp(data + i + 46, ".pack\n", 6)) {
 851                                 get_sha1_hex(data + i + 6, sha1);
 852                                 setup_index(repo, sha1);
 853                                 i += 51;
 854                                 break;
 855                         }
 856                 default:
 857                         while (data[i] != '\n')
 858                                 i++;
 859                 }
 860                 i++;
 861         }
 862
 863         free(buffer.buffer);
 864         repo->got_indices = 1;
 865         return 0;
 866 }
 867
 868 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 869 {
 870         char *url;
 871         struct packed_git *target;
 872         struct packed_git **lst;
 873         FILE *packfile;
 874         char *filename;
 875         char tmpfile[PATH_MAX];
 876         int ret;
 877         long prev_posn = 0;
 878         char range[RANGE_HEADER_SIZE];
 879         struct curl_slist *range_header = NULL;
 880
 881         struct active_request_slot *slot;
 882
 883         if (fetch_indices(repo))
 884                 return -1;
 885         target = find_sha1_pack(sha1, repo->packs);
 886         if (!target)
 887                 return -1;
 888
 889         if (get_verbosely) {
 890                 fprintf(stderr, "Getting pack %s\n",
 891                         sha1_to_hex(target->sha1));
 892                 fprintf(stderr, " which contains %s\n",
 893                         sha1_to_hex(sha1));
 894         }
 895
 896         url = xmalloc(strlen(repo->base) + 65);
 897         sprintf(url, "%s/objects/pack/pack-%s.pack",
 898                 repo->base, sha1_to_hex(target->sha1));
 899
 900         filename = sha1_pack_name(target->sha1);
 901         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 902         packfile = fopen(tmpfile, "a");
 903         if (!packfile)
 904                 return error("Unable to open local file %s for pack",
 905                              filename);
 906
 907         slot = get_active_slot();
 908         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 909         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 910         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 911         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 912         slot->local = packfile;
 913
 914         /* If there is data present from a previous transfer attempt,
 915            resume where it left off */
 916         prev_posn = ftell(packfile);
 917         if (prev_posn>0) {
 918                 if (get_verbosely)
 919                         fprintf(stderr,
 920                                 "Resuming fetch of pack %s at byte %ld\n",
 921                                 sha1_to_hex(target->sha1), prev_posn);
 922                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 923                 range_header = curl_slist_append(range_header, range);
 924                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 925         }
 926
 927         if (start_active_slot(slot)) {
 928                 run_active_slot(slot);
 929                 if (slot->curl_result != CURLE_OK) {
 930                         fclose(packfile);
 931                         return error("Unable to get pack file %s\n%s", url,
 932                                      curl_errorstr);
 933                 }
 934         } else {
 935                 return error("Unable to start request");
 936         }
 937
 938         fclose(packfile);
 939
 940         ret = move_temp_to_file(tmpfile, filename);
 941         if (ret)
 942                 return ret;
 943
 944         lst = &repo->packs;
 945         while (*lst != target)
 946                 lst = &((*lst)->next);
 947         *lst = (*lst)->next;
 948
 949         if (verify_pack(target, 0))
 950                 return -1;
 951         install_packed_git(target);
 952
 953         return 0;
 954 }
 955
 956 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 957 {
 958         char *hex = sha1_to_hex(sha1);
 959         int ret;
 960         struct transfer_request *request = request_queue_head;
 961
 962         while (request != NULL && memcmp(request->sha1, sha1, 20))
 963                 request = request->next;
 964         if (request == NULL)
 965                 return error("Couldn't find request for %s in the queue", hex);
 966
 967         if (has_sha1_file(request->sha1)) {
 968                 release_request(request);
 969                 return 0;
 970         }
 971
 972 #ifdef USE_CURL_MULTI
 973         int num_transfers;
 974         while (request->state == WAITING) {
 975                 curl_multi_perform(curlm, &num_transfers);
 976                 if (num_transfers < active_requests) {
 977                         process_curl_messages();
 978                         process_request_queue();
 979                 }
 980         }
 981 #else
 982         start_request(request);
 983 #endif
 984
 985         while (request->state == ACTIVE) {
 986                 run_active_slot(request->slot);
 987 #ifndef USE_CURL_MULTI
 988                 request->curl_result = request->slot->curl_result;
 989                 curl_easy_getinfo(request->slot->curl,
 990                                   CURLINFO_HTTP_CODE,
 991                                   &request->http_code);
 992                 request->slot = NULL;
 993
 994                 /* Use alternates if necessary */
 995                 if (request->http_code == 404 &&
 996                     request->repo->next != NULL) {
 997                         request->repo = request->repo->next;
 998                         start_request(request);
 999                 } else {
1000                         finish_request(request);
1001                         request->state = COMPLETE;
1002                 }
1003 #endif
1004         }
1005
1006         if (request->state == ABORTED) {
1007                 release_request(request);
1008                 return error("Request for %s aborted", hex);
1009         }
1010
1011         if (request->curl_result != CURLE_OK && request->http_code != 416) {
1012                 ret = error("%s", request->errorstr);
1013                 release_request(request);
1014                 return ret;
1015         }
1016
1017         if (request->zret != Z_STREAM_END) {
1018                 ret = error("File %s (%s) corrupt\n", hex, request->url);
1019                 release_request(request);
1020                 return ret;
1021         }
1022
1023         if (memcmp(request->sha1, request->real_sha1, 20)) {
1024                 release_request(request);
1025                 return error("File %s has bad hash\n", hex);
1026         }
1027
1028         if (request->rename < 0) {
1029                 ret = error("unable to write sha1 filename %s: %s",
1030                             request->filename,
1031                             strerror(request->rename));
1032                 release_request(request);
1033                 return ret;
1034         }
1035
1036         release_request(request);
1037         return 0;
1038 }
1039
1040 int fetch(unsigned char *sha1)
1041 {
1042         struct alt_base *altbase = alt;
1043
1044         if (!fetch_object(altbase, sha1))
1045                 return 0;
1046         while (altbase) {
1047                 if (!fetch_pack(altbase, sha1))
1048                         return 0;
1049                 altbase = altbase->next;
1050         }
1051         return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
1052                      alt->base);
1053 }
1054
1055 static inline int needs_quote(int ch)
1056 {
1057         switch (ch) {
1058         case '/': case '-': case '.':
1059         case 'A'...'Z': case 'a'...'z': case '0'...'9':
1060                 return 0;
1061         default:
1062                 return 1;
1063         }
1064 }
1065
1066 static inline int hex(int v)
1067 {
1068         if (v < 10) return '0' + v;
1069         else return 'A' + v - 10;
1070 }
1071
1072 static char *quote_ref_url(const char *base, const char *ref)
1073 {
1074         const char *cp;
1075         char *dp, *qref;
1076         int len, baselen, ch;
1077
1078         baselen = strlen(base);
1079         len = baselen + 6; /* "refs/" + NUL */
1080         for (cp = ref; (ch = *cp) != 0; cp++, len++)
1081                 if (needs_quote(ch))
1082                         len += 2; /* extra two hex plus replacement % */
1083         qref = xmalloc(len);
1084         memcpy(qref, base, baselen);
1085         memcpy(qref + baselen, "refs/", 5);
1086         for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
1087                 if (needs_quote(ch)) {
1088                         *dp++ = '%';
1089                         *dp++ = hex((ch >> 4) & 0xF);
1090                         *dp++ = hex(ch & 0xF);
1091                 }
1092                 else
1093                         *dp++ = ch;
1094         }
1095         *dp = 0;
1096
1097         return qref;
1098 }
1099
1100 int fetch_ref(char *ref, unsigned char *sha1)
1101 {
1102         char *url;
1103         char hex[42];
1104         struct buffer buffer;
1105         char *base = alt->base;
1106         struct active_request_slot *slot;
1107         buffer.size = 41;
1108         buffer.posn = 0;
1109         buffer.buffer = hex;
1110         hex[41] = '\0';
1111
1112         url = quote_ref_url(base, ref);
1113         slot = get_active_slot();
1114         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
1115         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
1116         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
1117         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1118         if (start_active_slot(slot)) {
1119                 run_active_slot(slot);
1120                 if (slot->curl_result != CURLE_OK)
1121                         return error("Couldn't get %s for %s\n%s",
1122                                      url, ref, curl_errorstr);
1123         } else {
1124                 return error("Unable to start request");
1125         }
1126
1127         hex[40] = '\0';
1128         get_sha1_hex(hex, sha1);
1129         return 0;
1130 }
1131
1132 int main(int argc, char **argv)
1133 {
1134         char *commit_id;
1135         char *url;
1136         int arg = 1;
1137         struct active_request_slot *slot;
1138
1139         while (arg < argc && argv[arg][0] == '-') {
1140                 if (argv[arg][1] == 't') {
1141                         get_tree = 1;
1142                 } else if (argv[arg][1] == 'c') {
1143                         get_history = 1;
1144                 } else if (argv[arg][1] == 'a') {
1145                         get_all = 1;
1146                         get_tree = 1;
1147                         get_history = 1;
1148                 } else if (argv[arg][1] == 'v') {
1149                         get_verbosely = 1;
1150                 } else if (argv[arg][1] == 'w') {
1151                         write_ref = argv[arg + 1];
1152                         arg++;
1153                 } else if (!strcmp(argv[arg], "--recover")) {
1154                         get_recover = 1;
1155                 }
1156                 arg++;
1157         }
1158         if (argc < arg + 2) {
1159                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1160                 return 1;
1161         }
1162         commit_id = argv[arg];
1163         url = argv[arg + 1];
1164
1165         curl_global_init(CURL_GLOBAL_ALL);
1166
1167 #ifdef USE_CURL_MULTI
1168         char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1169         if (http_max_requests != NULL)
1170                 max_requests = atoi(http_max_requests);
1171
1172         curlm = curl_multi_init();
1173         if (curlm == NULL) {
1174                 fprintf(stderr, "Error creating curl multi handle.\n");
1175                 return 1;
1176         }
1177 #endif
1178
1179         if (getenv("GIT_SSL_NO_VERIFY"))
1180                 curl_ssl_verify = 0;
1181
1182         ssl_cert = getenv("GIT_SSL_CERT");
1183 #if LIBCURL_VERSION_NUM >= 0x070902
1184         ssl_key = getenv("GIT_SSL_KEY");
1185 #endif
1186 #if LIBCURL_VERSION_NUM >= 0x070908
1187         ssl_capath = getenv("GIT_SSL_CAPATH");
1188 #endif
1189         ssl_cainfo = getenv("GIT_SSL_CAINFO");
1190
1191         git_config(http_options);
1192
1193         if (curl_ssl_verify == -1)
1194                 curl_ssl_verify = 1;
1195
1196 #ifdef USE_CURL_MULTI
1197         if (max_requests < 1)
1198                 max_requests = DEFAULT_MAX_REQUESTS;
1199 #endif
1200
1201         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
1202         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1203         no_range_header = curl_slist_append(no_range_header, "Range:");
1204
1205         curl_default = curl_easy_init();
1206
1207         curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1208 #if LIBCURL_VERSION_NUM >= 0x070907
1209         curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1210 #endif
1211
1212         if (ssl_cert != NULL)
1213                 curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1214         if (ssl_key != NULL)
1215                 curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1216         if (ssl_capath != NULL)
1217                 curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1218         if (ssl_cainfo != NULL)
1219                 curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1220
1221         curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1222
1223         alt = xmalloc(sizeof(*alt));
1224         alt->base = url;
1225         alt->got_indices = 0;
1226         alt->packs = NULL;
1227         alt->next = NULL;
1228         fetch_alternates(alt->base);
1229
1230         if (pull(commit_id))
1231                 return 1;
1232
1233         curl_slist_free_all(pragma_header);
1234         curl_slist_free_all(no_pragma_header);
1235         curl_slist_free_all(no_range_header);
1236         curl_easy_cleanup(curl_default);
1237         slot = active_queue_head;
1238         while (slot != NULL) {
1239                 curl_easy_cleanup(slot->curl);
1240                 slot = slot->next;
1241         }
1242 #ifdef USE_CURL_MULTI
1243         curl_multi_cleanup(curlm);
1244 #endif
1245         curl_global_cleanup();
1246         return 0;
1247 }