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 *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;
  89 static char *ssl_cert;
  90 static char *ssl_key;
  91 static char *ssl_capath;
  92 static char *ssl_cainfo;
  93
  94 struct buffer
  95 {
  96         size_t posn;
  97         size_t size;
  98         void *buffer;
  99 };
 100
 101 static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
 102                             struct buffer *buffer)
 103 {
 104         size_t size = eltsize * nmemb;
 105         if (size > buffer->size - buffer->posn)
 106                 size = buffer->size - buffer->posn;
 107         memcpy(buffer->buffer + buffer->posn, ptr, size);
 108         buffer->posn += size;
 109         data_received++;
 110         return size;
 111 }
 112
 113 static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 114                                void *data)
 115 {
 116         unsigned char expn[4096];
 117         size_t size = eltsize * nmemb;
 118         int posn = 0;
 119         struct transfer_request *request = (struct transfer_request *)data;
 120         do {
 121                 ssize_t retval = write(request->local,
 122                                        ptr + posn, size - posn);
 123                 if (retval < 0)
 124                         return posn;
 125                 posn += retval;
 126         } while (posn < size);
 127
 128         request->stream.avail_in = size;
 129         request->stream.next_in = ptr;
 130         do {
 131                 request->stream.next_out = expn;
 132                 request->stream.avail_out = sizeof(expn);
 133                 request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
 134                 SHA1_Update(&request->c, expn,
 135                             sizeof(expn) - request->stream.avail_out);
 136         } while (request->stream.avail_in && request->zret == Z_OK);
 137         data_received++;
 138         return size;
 139 }
 140
 141 #ifdef USE_CURL_MULTI
 142 void process_curl_messages();
 143 void process_request_queue();
 144 #endif
 145
 146 struct active_request_slot *get_active_slot()
 147 {
 148         struct active_request_slot *slot = active_queue_head;
 149         struct active_request_slot *newslot;
 150
 151 #ifdef USE_CURL_MULTI
 152         int num_transfers;
 153
 154         /* Wait for a slot to open up if the queue is full */
 155         while (active_requests >= max_requests) {
 156                 curl_multi_perform(curlm, &num_transfers);
 157                 if (num_transfers < active_requests) {
 158                         process_curl_messages();
 159                 }
 160         }
 161 #endif
 162
 163         while (slot != NULL && slot->in_use) {
 164                 slot = slot->next;
 165         }
 166         if (slot == NULL) {
 167                 newslot = xmalloc(sizeof(*newslot));
 168                 newslot->curl = curl_easy_duphandle(curl_default);
 169                 newslot->in_use = 0;
 170                 newslot->next = NULL;
 171
 172                 slot = active_queue_head;
 173                 if (slot == NULL) {
 174                         active_queue_head = newslot;
 175                 } else {
 176                         while (slot->next != NULL) {
 177                                 slot = slot->next;
 178                         }
 179                         slot->next = newslot;
 180                 }
 181                 slot = newslot;
 182         }
 183
 184         active_requests++;
 185         slot->in_use = 1;
 186         slot->done = 0;
 187         slot->local = NULL;
 188         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 189         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 190         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 191
 192         return slot;
 193 }
 194
 195 int start_active_slot(struct active_request_slot *slot)
 196 {
 197 #ifdef USE_CURL_MULTI
 198         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 199
 200         if (curlm_result != CURLM_OK &&
 201             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 202                 active_requests--;
 203                 slot->in_use = 0;
 204                 return 0;
 205         }
 206 #endif
 207         return 1;
 208 }
 209
 210 void run_active_slot(struct active_request_slot *slot)
 211 {
 212 #ifdef USE_CURL_MULTI
 213         int num_transfers;
 214         long last_pos = 0;
 215         long current_pos;
 216         fd_set readfds;
 217         fd_set writefds;
 218         fd_set excfds;
 219         int max_fd;
 220         struct timeval select_timeout;
 221         CURLMcode curlm_result;
 222
 223         while (!slot->done) {
 224                 data_received = 0;
 225                 do {
 226                         curlm_result = curl_multi_perform(curlm,
 227                                                           &num_transfers);
 228                 } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 229                 if (num_transfers < active_requests) {
 230                         process_curl_messages();
 231                         process_request_queue();
 232                 }
 233
 234                 if (!data_received && slot->local != NULL) {
 235                         current_pos = ftell(slot->local);
 236                         if (current_pos > last_pos)
 237                                 data_received++;
 238                         last_pos = current_pos;
 239                 }
 240
 241                 if (!slot->done && !data_received) {
 242                         max_fd = 0;
 243                         FD_ZERO(&readfds);
 244                         FD_ZERO(&writefds);
 245                         FD_ZERO(&excfds);
 246                         select_timeout.tv_sec = 0;
 247                         select_timeout.tv_usec = 50000;
 248                         select(max_fd, &readfds, &writefds,
 249                                &excfds, &select_timeout);
 250                 }
 251         }
 252 #else
 253         slot->curl_result = curl_easy_perform(slot->curl);
 254         active_requests--;
 255 #endif
 256 }
 257
 258 void start_request(struct transfer_request *request)
 259 {
 260         char *hex = sha1_to_hex(request->sha1);
 261         char prevfile[PATH_MAX];
 262         char *url;
 263         char *posn;
 264         int prevlocal;
 265         unsigned char prev_buf[PREV_BUF_SIZE];
 266         ssize_t prev_read = 0;
 267         long prev_posn = 0;
 268         char range[RANGE_HEADER_SIZE];
 269         struct curl_slist *range_header = NULL;
 270         struct active_request_slot *slot;
 271
 272         snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 273         unlink(prevfile);
 274         rename(request->tmpfile, prevfile);
 275         unlink(request->tmpfile);
 276
 277         request->local = open(request->tmpfile,
 278                               O_WRONLY | O_CREAT | O_EXCL, 0666);
 279         /* This could have failed due to the "lazy directory creation";
 280          * try to mkdir the last path component.
 281          */
 282         if (request->local < 0 && errno == ENOENT) {
 283                 char *dir = strrchr(request->tmpfile, '/');
 284                 if (dir) {
 285                         *dir = 0;
 286                         mkdir(request->tmpfile, 0777);
 287                         *dir = '/';
 288                 }
 289                 request->local = open(request->tmpfile,
 290                                       O_WRONLY | O_CREAT | O_EXCL, 0666);
 291         }
 292
 293         if (request->local < 0) {
 294                 request->state = ABORTED;
 295                 error("Couldn't create temporary file %s for %s: %s\n",
 296                       request->tmpfile, request->filename, strerror(errno));
 297                 return;
 298         }
 299
 300         memset(&request->stream, 0, sizeof(request->stream));
 301
 302         inflateInit(&request->stream);
 303
 304         SHA1_Init(&request->c);
 305
 306         url = xmalloc(strlen(request->repo->base) + 50);
 307         request->url = xmalloc(strlen(request->repo->base) + 50);
 308         strcpy(url, request->repo->base);
 309         posn = url + strlen(request->repo->base);
 310         strcpy(posn, "objects/");
 311         posn += 8;
 312         memcpy(posn, hex, 2);
 313         posn += 2;
 314         *(posn++) = '/';
 315         strcpy(posn, hex + 2);
 316         strcpy(request->url, url);
 317
 318         /* If a previous temp file is present, process what was already
 319            fetched. */
 320         prevlocal = open(prevfile, O_RDONLY);
 321         if (prevlocal != -1) {
 322                 do {
 323                         prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 324                         if (prev_read>0) {
 325                                 if (fwrite_sha1_file(prev_buf,
 326                                                      1,
 327                                                      prev_read,
 328                                                      request) == prev_read) {
 329                                         prev_posn += prev_read;
 330                                 } else {
 331                                         prev_read = -1;
 332                                 }
 333                         }
 334                 } while (prev_read > 0);
 335                 close(prevlocal);
 336         }
 337         unlink(prevfile);
 338
 339         /* Reset inflate/SHA1 if there was an error reading the previous temp
 340            file; also rewind to the beginning of the local file. */
 341         if (prev_read == -1) {
 342                 memset(&request->stream, 0, sizeof(request->stream));
 343                 inflateInit(&request->stream);
 344                 SHA1_Init(&request->c);
 345                 if (prev_posn>0) {
 346                         prev_posn = 0;
 347                         lseek(request->local, SEEK_SET, 0);
 348                         ftruncate(request->local, 0);
 349                 }
 350         }
 351
 352         slot = get_active_slot();
 353         curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 354         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 355         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 356         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 357         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 358
 359         /* If we have successfully processed data from a previous fetch
 360            attempt, only fetch the data we don't already have. */
 361         if (prev_posn>0) {
 362                 if (get_verbosely)
 363                         fprintf(stderr,
 364                                 "Resuming fetch of object %s at byte %ld\n",
 365                                 hex, prev_posn);
 366                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 367                 range_header = curl_slist_append(range_header, range);
 368                 curl_easy_setopt(slot->curl,
 369                                  CURLOPT_HTTPHEADER, range_header);
 370         }
 371
 372         /* Try to get the request started, abort the request on error */
 373         if (!start_active_slot(slot)) {
 374                 request->state = ABORTED;
 375                 close(request->local);
 376                 free(request->url);
 377                 return;
 378         }
 379
 380         request->slot = slot;
 381         request->state = ACTIVE;
 382 }
 383
 384 void finish_request(struct transfer_request *request)
 385 {
 386         fchmod(request->local, 0444);
 387         close(request->local);
 388
 389         if (request->http_code == 416) {
 390                 fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 391         } else if (request->curl_result != CURLE_OK) {
 392                 return;
 393         }
 394
 395         inflateEnd(&request->stream);
 396         SHA1_Final(request->real_sha1, &request->c);
 397         if (request->zret != Z_STREAM_END) {
 398                 unlink(request->tmpfile);
 399                 return;
 400         }
 401         if (memcmp(request->sha1, request->real_sha1, 20)) {
 402                 unlink(request->tmpfile);
 403                 return;
 404         }
 405         request->rename =
 406                 move_temp_to_file(request->tmpfile, request->filename);
 407
 408         if (request->rename == 0)
 409                 pull_say("got %s\n", sha1_to_hex(request->sha1));
 410 }
 411
 412 void release_request(struct transfer_request *request)
 413 {
 414         struct transfer_request *entry = request_queue_head;
 415
 416         if (request == request_queue_head) {
 417                 request_queue_head = request->next;
 418         } else {
 419                 while (entry->next != NULL && entry->next != request)
 420                         entry = entry->next;
 421                 if (entry->next == request)
 422                         entry->next = entry->next->next;
 423         }
 424
 425         free(request->url);
 426         free(request);
 427 }
 428
 429 #ifdef USE_CURL_MULTI
 430 void process_curl_messages()
 431 {
 432         int num_messages;
 433         struct active_request_slot *slot;
 434         struct transfer_request *request = NULL;
 435         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 436
 437         while (curl_message != NULL) {
 438                 if (curl_message->msg == CURLMSG_DONE) {
 439                         slot = active_queue_head;
 440                         while (slot != NULL &&
 441                                slot->curl != curl_message->easy_handle)
 442                                 slot = slot->next;
 443                         if (slot != NULL) {
 444                                 curl_multi_remove_handle(curlm, slot->curl);
 445                                 active_requests--;
 446                                 slot->done = 1;
 447                                 slot->in_use = 0;
 448                                 slot->curl_result = curl_message->data.result;
 449                                 request = request_queue_head;
 450                                 while (request != NULL &&
 451                                        request->slot != slot)
 452                                         request = request->next;
 453                         } else {
 454                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 455                         }
 456                         if (request != NULL) {
 457                                 request->curl_result =
 458                                         curl_message->data.result;
 459                                 curl_easy_getinfo(slot->curl,
 460                                                   CURLINFO_HTTP_CODE,
 461                                                   &request->http_code);
 462                                 request->slot = NULL;
 463
 464                                 /* Use alternates if necessary */
 465                                 if (request->http_code == 404 &&
 466                                     request->repo->next != NULL) {
 467                                         request->repo = request->repo->next;
 468                                         start_request(request);
 469                                 } else {
 470                                         finish_request(request);
 471                                         request->state = COMPLETE;
 472                                 }
 473                         }
 474                 } else {
 475                         fprintf(stderr, "Unknown CURL message received: %d\n",
 476                                 (int)curl_message->msg);
 477                 }
 478                 curl_message = curl_multi_info_read(curlm, &num_messages);
 479         }
 480 }
 481
 482 void process_request_queue()
 483 {
 484         struct transfer_request *request = request_queue_head;
 485         int num_transfers;
 486
 487         while (active_requests < max_requests && request != NULL) {
 488                 if (request->state == WAITING) {
 489                         if (has_sha1_file(request->sha1))
 490                                 release_request(request);
 491                         else
 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         long prev_posn = 0;
 541         char range[RANGE_HEADER_SIZE];
 542         struct curl_slist *range_header = NULL;
 543
 544         FILE *indexfile;
 545         struct active_request_slot *slot;
 546
 547         if (has_pack_index(sha1))
 548                 return 0;
 549
 550         if (get_verbosely)
 551                 fprintf(stderr, "Getting index for pack %s\n", hex);
 552
 553         url = xmalloc(strlen(repo->base) + 64);
 554         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 555
 556         filename = sha1_pack_index_name(sha1);
 557         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 558         indexfile = fopen(tmpfile, "a");
 559         if (!indexfile)
 560                 return error("Unable to open local file %s for pack index",
 561                              filename);
 562
 563         slot = get_active_slot();
 564         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 565         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 566         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 567         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 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         return move_temp_to_file(tmpfile, filename);
 597 }
 598
 599 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 600 {
 601         struct packed_git *new_pack;
 602         if (has_pack_file(sha1))
 603                 return 0; // don't list this as something we can get
 604
 605         if (fetch_index(repo, sha1))
 606                 return -1;
 607
 608         new_pack = parse_pack_index(sha1);
 609         new_pack->next = repo->packs;
 610         repo->packs = new_pack;
 611         return 0;
 612 }
 613
 614 static int fetch_alternates(char *base)
 615 {
 616         int ret = 0;
 617         struct buffer buffer;
 618         char *url;
 619         char *data;
 620         int i = 0;
 621         int http_specific = 1;
 622         struct alt_base *tail = alt;
 623
 624         struct active_request_slot *slot;
 625         if (got_alternates)
 626                 return 0;
 627         data = xmalloc(4096);
 628         buffer.size = 4095;
 629         buffer.posn = 0;
 630         buffer.buffer = data;
 631
 632         if (get_verbosely)
 633                 fprintf(stderr, "Getting alternates list\n");
 634
 635         url = xmalloc(strlen(base) + 31);
 636         sprintf(url, "%s/objects/info/http-alternates", base);
 637
 638         slot = get_active_slot();
 639         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 640         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 641         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 642         if (start_active_slot(slot)) {
 643                 run_active_slot(slot);
 644                 if (slot->curl_result != CURLE_OK || !buffer.posn) {
 645                         http_specific = 0;
 646
 647                         sprintf(url, "%s/objects/info/alternates", base);
 648
 649                         slot = get_active_slot();
 650                         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 651                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 652                                          fwrite_buffer);
 653                         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 654                         if (start_active_slot(slot)) {
 655                                 run_active_slot(slot);
 656                                 if (slot->curl_result != CURLE_OK) {
 657                                         return 0;
 658                                 }
 659                         }
 660                 }
 661         } else {
 662                 return 0;
 663         }
 664
 665         data[buffer.posn] = '\0';
 666
 667         while (i < buffer.posn) {
 668                 int posn = i;
 669                 while (posn < buffer.posn && data[posn] != '\n')
 670                         posn++;
 671                 if (data[posn] == '\n') {
 672                         int okay = 0;
 673                         int serverlen = 0;
 674                         struct alt_base *newalt;
 675                         char *target = NULL;
 676                         if (data[i] == '/') {
 677                                 serverlen = strchr(base + 8, '/') - base;
 678                                 okay = 1;
 679                         } else if (!memcmp(data + i, "../", 3)) {
 680                                 i += 3;
 681                                 serverlen = strlen(base);
 682                                 while (i + 2 < posn &&
 683                                        !memcmp(data + i, "../", 3)) {
 684                                         do {
 685                                                 serverlen--;
 686                                         } while (serverlen &&
 687                                                  base[serverlen - 1] != '/');
 688                                         i += 3;
 689                                 }
 690                                 // If the server got removed, give up.
 691                                 okay = strchr(base, ':') - base + 3 <
 692                                         serverlen;
 693                         } else if (http_specific) {
 694                                 char *colon = strchr(data + i, ':');
 695                                 char *slash = strchr(data + i, '/');
 696                                 if (colon && slash && colon < data + posn &&
 697                                     slash < data + posn && colon < slash) {
 698                                         okay = 1;
 699                                 }
 700                         }
 701                         // skip 'objects' at end
 702                         if (okay) {
 703                                 target = xmalloc(serverlen + posn - i - 6);
 704                                 strncpy(target, base, serverlen);
 705                                 strncpy(target + serverlen, data + i,
 706                                         posn - i - 7);
 707                                 target[serverlen + posn - i - 7] = '\0';
 708                                 if (get_verbosely)
 709                                         fprintf(stderr,
 710                                                 "Also look at %s\n", target);
 711                                 newalt = xmalloc(sizeof(*newalt));
 712                                 newalt->next = NULL;
 713                                 newalt->base = target;
 714                                 newalt->got_indices = 0;
 715                                 newalt->packs = NULL;
 716                                 while (tail->next != NULL)
 717                                         tail = tail->next;
 718                                 tail->next = newalt;
 719                                 ret++;
 720                         }
 721                 }
 722                 i = posn + 1;
 723         }
 724         got_alternates = 1;
 725
 726         return ret;
 727 }
 728
 729 static int fetch_indices(struct alt_base *repo)
 730 {
 731         unsigned char sha1[20];
 732         char *url;
 733         struct buffer buffer;
 734         char *data;
 735         int i = 0;
 736
 737         struct active_request_slot *slot;
 738
 739         if (repo->got_indices)
 740                 return 0;
 741
 742         data = xmalloc(4096);
 743         buffer.size = 4096;
 744         buffer.posn = 0;
 745         buffer.buffer = data;
 746
 747         if (get_verbosely)
 748                 fprintf(stderr, "Getting pack list\n");
 749
 750         url = xmalloc(strlen(repo->base) + 21);
 751         sprintf(url, "%s/objects/info/packs", repo->base);
 752
 753         slot = get_active_slot();
 754         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 755         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 756         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 757         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 758         if (start_active_slot(slot)) {
 759                 run_active_slot(slot);
 760                 if (slot->curl_result != CURLE_OK)
 761                         return error("%s", curl_errorstr);
 762         } else {
 763                 return error("Unable to start request");
 764         }
 765
 766         while (i < buffer.posn) {
 767                 switch (data[i]) {
 768                 case 'P':
 769                         i++;
 770                         if (i + 52 < buffer.posn &&
 771                             !strncmp(data + i, " pack-", 6) &&
 772                             !strncmp(data + i + 46, ".pack\n", 6)) {
 773                                 get_sha1_hex(data + i + 6, sha1);
 774                                 setup_index(repo, sha1);
 775                                 i += 51;
 776                                 break;
 777                         }
 778                 default:
 779                         while (data[i] != '\n')
 780                                 i++;
 781                 }
 782                 i++;
 783         }
 784
 785         repo->got_indices = 1;
 786         return 0;
 787 }
 788
 789 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 790 {
 791         char *url;
 792         struct packed_git *target;
 793         struct packed_git **lst;
 794         FILE *packfile;
 795         char *filename;
 796         char tmpfile[PATH_MAX];
 797         int ret;
 798         long prev_posn = 0;
 799         char range[RANGE_HEADER_SIZE];
 800         struct curl_slist *range_header = NULL;
 801
 802         struct active_request_slot *slot;
 803
 804         if (fetch_indices(repo))
 805                 return -1;
 806         target = find_sha1_pack(sha1, repo->packs);
 807         if (!target)
 808                 return -1;
 809
 810         if (get_verbosely) {
 811                 fprintf(stderr, "Getting pack %s\n",
 812                         sha1_to_hex(target->sha1));
 813                 fprintf(stderr, " which contains %s\n",
 814                         sha1_to_hex(sha1));
 815         }
 816
 817         url = xmalloc(strlen(repo->base) + 65);
 818         sprintf(url, "%s/objects/pack/pack-%s.pack",
 819                 repo->base, sha1_to_hex(target->sha1));
 820
 821         filename = sha1_pack_name(target->sha1);
 822         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 823         packfile = fopen(tmpfile, "a");
 824         if (!packfile)
 825                 return error("Unable to open local file %s for pack",
 826                              filename);
 827
 828         slot = get_active_slot();
 829         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 830         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 831         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 832         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 833         slot->local = packfile;
 834
 835         /* If there is data present from a previous transfer attempt,
 836            resume where it left off */
 837         prev_posn = ftell(packfile);
 838         if (prev_posn>0) {
 839                 if (get_verbosely)
 840                         fprintf(stderr,
 841                                 "Resuming fetch of pack %s at byte %ld\n",
 842                                 sha1_to_hex(target->sha1), prev_posn);
 843                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 844                 range_header = curl_slist_append(range_header, range);
 845                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 846         }
 847
 848         if (start_active_slot(slot)) {
 849                 run_active_slot(slot);
 850                 if (slot->curl_result != CURLE_OK) {
 851                         fclose(packfile);
 852                         return error("Unable to get pack file %s\n%s", url,
 853                                      curl_errorstr);
 854                 }
 855         } else {
 856                 return error("Unable to start request");
 857         }
 858
 859         fclose(packfile);
 860
 861         ret = move_temp_to_file(tmpfile, filename);
 862         if (ret)
 863                 return ret;
 864
 865         lst = &repo->packs;
 866         while (*lst != target)
 867                 lst = &((*lst)->next);
 868         *lst = (*lst)->next;
 869
 870         if (verify_pack(target, 0))
 871                 return -1;
 872         install_packed_git(target);
 873
 874         return 0;
 875 }
 876
 877 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 878 {
 879         char *hex = sha1_to_hex(sha1);
 880         int ret;
 881         struct transfer_request *request = request_queue_head;
 882
 883         while (request != NULL && memcmp(request->sha1, sha1, 20))
 884                 request = request->next;
 885         if (request == NULL)
 886                 return error("Couldn't find request for %s in the queue", hex);
 887
 888         if (has_sha1_file(request->sha1)) {
 889                 release_request(request);
 890                 return 0;
 891         }
 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         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
1063         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1064         no_range_header = curl_slist_append(no_range_header, "Range:");
1065
1066         curl_default = curl_easy_init();
1067
1068         curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
1069         curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1070 #if LIBCURL_VERSION_NUM >= 0x070907
1071         curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1072 #endif
1073
1074         if ((ssl_cert = getenv("GIT_SSL_CERT")) != NULL) {
1075                 curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1076         }
1077 #if LIBCURL_VERSION_NUM >= 0x070902
1078         if ((ssl_key = getenv("GIT_SSL_KEY")) != NULL) {
1079                 curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1080         }
1081 #endif
1082 #if LIBCURL_VERSION_NUM >= 0x070908
1083         if ((ssl_capath = getenv("GIT_SSL_CAPATH")) != NULL) {
1084                 curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1085         }
1086 #endif
1087         if ((ssl_cainfo = getenv("GIT_SSL_CAINFO")) != NULL) {
1088                 curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1089         }
1090         curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1091
1092         alt = xmalloc(sizeof(*alt));
1093         alt->base = url;
1094         alt->got_indices = 0;
1095         alt->packs = NULL;
1096         alt->next = NULL;
1097         fetch_alternates(alt->base);
1098
1099         if (pull(commit_id))
1100                 return 1;
1101
1102         curl_slist_free_all(pragma_header);
1103         curl_slist_free_all(no_pragma_header);
1104         curl_slist_free_all(no_range_header);
1105         curl_easy_cleanup(curl_default);
1106         slot = active_queue_head;
1107         while (slot != NULL) {
1108                 curl_easy_cleanup(slot->curl);
1109                 slot = slot->next;
1110         }
1111 #ifdef USE_CURL_MULTI
1112         curl_multi_cleanup(curlm);
1113 #endif
1114         curl_global_cleanup();
1115         return 0;
1116 }