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 int relink_or_rename(char *old, char *new) {
 142         int ret;
 143
 144         ret = link(old, new);
 145         if (ret < 0) {
 146                 /* Same Coda hack as in write_sha1_file(sha1_file.c) */
 147                 ret = errno;
 148                 if (ret == EXDEV && !rename(old, new))
 149                         return 0;
 150         }
 151         unlink(old);
 152         if (ret) {
 153                 if (ret != EEXIST)
 154                         return ret;
 155         }
 156
 157         return 0;
 158 }
 159
 160 #ifdef USE_CURL_MULTI
 161 void process_curl_messages();
 162 void process_request_queue();
 163 #endif
 164
 165 struct active_request_slot *get_active_slot()
 166 {
 167         struct active_request_slot *slot = active_queue_head;
 168         struct active_request_slot *newslot;
 169
 170 #ifdef USE_CURL_MULTI
 171         int num_transfers;
 172
 173         /* Wait for a slot to open up if the queue is full */
 174         while (active_requests >= max_requests) {
 175                 curl_multi_perform(curlm, &num_transfers);
 176                 if (num_transfers < active_requests) {
 177                         process_curl_messages();
 178                 }
 179         }
 180 #endif
 181
 182         while (slot != NULL && slot->in_use) {
 183                 slot = slot->next;
 184         }
 185         if (slot == NULL) {
 186                 newslot = xmalloc(sizeof(*newslot));
 187                 newslot->curl = curl_easy_duphandle(curl_default);
 188                 newslot->in_use = 0;
 189                 newslot->next = NULL;
 190
 191                 slot = active_queue_head;
 192                 if (slot == NULL) {
 193                         active_queue_head = newslot;
 194                 } else {
 195                         while (slot->next != NULL) {
 196                                 slot = slot->next;
 197                         }
 198                         slot->next = newslot;
 199                 }
 200                 slot = newslot;
 201         }
 202
 203         active_requests++;
 204         slot->in_use = 1;
 205         slot->done = 0;
 206         slot->local = NULL;
 207         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 208         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 209         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 210
 211         return slot;
 212 }
 213
 214 int start_active_slot(struct active_request_slot *slot)
 215 {
 216 #ifdef USE_CURL_MULTI
 217         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 218
 219         if (curlm_result != CURLM_OK &&
 220             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 221                 active_requests--;
 222                 slot->in_use = 0;
 223                 return 0;
 224         }
 225 #endif
 226         return 1;
 227 }
 228
 229 void run_active_slot(struct active_request_slot *slot)
 230 {
 231 #ifdef USE_CURL_MULTI
 232         int num_transfers;
 233         long last_pos = 0;
 234         long current_pos;
 235         fd_set readfds;
 236         fd_set writefds;
 237         fd_set excfds;
 238         int max_fd;
 239         struct timeval select_timeout;
 240         CURLMcode curlm_result;
 241
 242         while (!slot->done) {
 243                 data_received = 0;
 244                 do {
 245                         curlm_result = curl_multi_perform(curlm,
 246                                                           &num_transfers);
 247                 } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 248                 if (num_transfers < active_requests) {
 249                         process_curl_messages();
 250                         process_request_queue();
 251                 }
 252
 253                 if (!data_received && slot->local != NULL) {
 254                         current_pos = ftell(slot->local);
 255                         if (current_pos > last_pos)
 256                                 data_received++;
 257                         last_pos = current_pos;
 258                 }
 259
 260                 if (!slot->done && !data_received) {
 261                         max_fd = 0;
 262                         FD_ZERO(&readfds);
 263                         FD_ZERO(&writefds);
 264                         FD_ZERO(&excfds);
 265                         select_timeout.tv_sec = 0;
 266                         select_timeout.tv_usec = 50000;
 267                         select(max_fd, &readfds, &writefds,
 268                                &excfds, &select_timeout);
 269                 }
 270         }
 271 #else
 272         slot->curl_result = curl_easy_perform(slot->curl);
 273         active_requests--;
 274 #endif
 275 }
 276
 277 void start_request(struct transfer_request *request)
 278 {
 279         char *hex = sha1_to_hex(request->sha1);
 280         char prevfile[PATH_MAX];
 281         char *url;
 282         char *posn;
 283         int prevlocal;
 284         unsigned char prev_buf[PREV_BUF_SIZE];
 285         ssize_t prev_read = 0;
 286         long prev_posn = 0;
 287         char range[RANGE_HEADER_SIZE];
 288         struct curl_slist *range_header = NULL;
 289         struct active_request_slot *slot;
 290
 291         snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 292         unlink(prevfile);
 293         rename(request->tmpfile, prevfile);
 294         unlink(request->tmpfile);
 295
 296         request->local = open(request->tmpfile,
 297                               O_WRONLY | O_CREAT | O_EXCL, 0666);
 298         if (request->local < 0) {
 299                 request->state = ABORTED;
 300                 error("Couldn't create temporary file %s for %s: %s\n",
 301                       request->tmpfile, request->filename, strerror(errno));
 302                 return;
 303         }
 304
 305         memset(&request->stream, 0, sizeof(request->stream));
 306
 307         inflateInit(&request->stream);
 308
 309         SHA1_Init(&request->c);
 310
 311         url = xmalloc(strlen(request->repo->base) + 50);
 312         request->url = xmalloc(strlen(request->repo->base) + 50);
 313         strcpy(url, request->repo->base);
 314         posn = url + strlen(request->repo->base);
 315         strcpy(posn, "objects/");
 316         posn += 8;
 317         memcpy(posn, hex, 2);
 318         posn += 2;
 319         *(posn++) = '/';
 320         strcpy(posn, hex + 2);
 321         strcpy(request->url, url);
 322
 323         /* If a previous temp file is present, process what was already
 324            fetched. */
 325         prevlocal = open(prevfile, O_RDONLY);
 326         if (prevlocal != -1) {
 327                 do {
 328                         prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 329                         if (prev_read>0) {
 330                                 if (fwrite_sha1_file(prev_buf,
 331                                                      1,
 332                                                      prev_read,
 333                                                      request) == prev_read) {
 334                                         prev_posn += prev_read;
 335                                 } else {
 336                                         prev_read = -1;
 337                                 }
 338                         }
 339                 } while (prev_read > 0);
 340                 close(prevlocal);
 341         }
 342         unlink(prevfile);
 343
 344         /* Reset inflate/SHA1 if there was an error reading the previous temp
 345            file; also rewind to the beginning of the local file. */
 346         if (prev_read == -1) {
 347                 memset(&request->stream, 0, sizeof(request->stream));
 348                 inflateInit(&request->stream);
 349                 SHA1_Init(&request->c);
 350                 if (prev_posn>0) {
 351                         prev_posn = 0;
 352                         lseek(request->local, SEEK_SET, 0);
 353                         ftruncate(request->local, 0);
 354                 }
 355         }
 356
 357         slot = get_active_slot();
 358         curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 359         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 360         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 361         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 362         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 363
 364         /* If we have successfully processed data from a previous fetch
 365            attempt, only fetch the data we don't already have. */
 366         if (prev_posn>0) {
 367                 if (get_verbosely)
 368                         fprintf(stderr,
 369                                 "Resuming fetch of object %s at byte %ld\n",
 370                                 hex, prev_posn);
 371                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 372                 range_header = curl_slist_append(range_header, range);
 373                 curl_easy_setopt(slot->curl,
 374                                  CURLOPT_HTTPHEADER, range_header);
 375         }
 376
 377         /* Try to get the request started, abort the request on error */
 378         if (!start_active_slot(slot)) {
 379                 request->state = ABORTED;
 380                 close(request->local);
 381                 free(request->url);
 382                 return;
 383         }
 384
 385         request->slot = slot;
 386         request->state = ACTIVE;
 387 }
 388
 389 void finish_request(struct transfer_request *request)
 390 {
 391         fchmod(request->local, 0444);
 392         close(request->local);
 393
 394         if (request->http_code == 416) {
 395                 fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 396         } else if (request->curl_result != CURLE_OK) {
 397                 return;
 398         }
 399
 400         inflateEnd(&request->stream);
 401         SHA1_Final(request->real_sha1, &request->c);
 402         if (request->zret != Z_STREAM_END) {
 403                 unlink(request->tmpfile);
 404                 return;
 405         }
 406         if (memcmp(request->sha1, request->real_sha1, 20)) {
 407                 unlink(request->tmpfile);
 408                 return;
 409         }
 410         request->rename =
 411                 relink_or_rename(request->tmpfile, request->filename);
 412
 413         if (request->rename == 0)
 414                 pull_say("got %s\n", sha1_to_hex(request->sha1));
 415 }
 416
 417 void release_request(struct transfer_request *request)
 418 {
 419         struct transfer_request *entry = request_queue_head;
 420
 421         if (request == request_queue_head) {
 422                 request_queue_head = request->next;
 423         } else {
 424                 while (entry->next != NULL && entry->next != request)
 425                         entry = entry->next;
 426                 if (entry->next == request)
 427                         entry->next = entry->next->next;
 428         }
 429
 430         free(request->url);
 431         free(request);
 432 }
 433
 434 #ifdef USE_CURL_MULTI
 435 void process_curl_messages()
 436 {
 437         int num_messages;
 438         struct active_request_slot *slot;
 439         struct transfer_request *request = NULL;
 440         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 441
 442         while (curl_message != NULL) {
 443                 if (curl_message->msg == CURLMSG_DONE) {
 444                         slot = active_queue_head;
 445                         while (slot != NULL &&
 446                                slot->curl != curl_message->easy_handle)
 447                                 slot = slot->next;
 448                         if (slot != NULL) {
 449                                 curl_multi_remove_handle(curlm, slot->curl);
 450                                 active_requests--;
 451                                 slot->done = 1;
 452                                 slot->in_use = 0;
 453                                 slot->curl_result = curl_message->data.result;
 454                                 request = request_queue_head;
 455                                 while (request != NULL &&
 456                                        request->slot != slot)
 457                                         request = request->next;
 458                         } else {
 459                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 460                         }
 461                         if (request != NULL) {
 462                                 request->curl_result =
 463                                         curl_message->data.result;
 464                                 curl_easy_getinfo(slot->curl,
 465                                                   CURLINFO_HTTP_CODE,
 466                                                   &request->http_code);
 467                                 request->slot = NULL;
 468
 469                                 /* Use alternates if necessary */
 470                                 if (request->http_code == 404 &&
 471                                     request->repo->next != NULL) {
 472                                         request->repo = request->repo->next;
 473                                         start_request(request);
 474                                 } else {
 475                                         finish_request(request);
 476                                         request->state = COMPLETE;
 477                                 }
 478                         }
 479                 } else {
 480                         fprintf(stderr, "Unknown CURL message received: %d\n",
 481                                 (int)curl_message->msg);
 482                 }
 483                 curl_message = curl_multi_info_read(curlm, &num_messages);
 484         }
 485 }
 486
 487 void process_request_queue()
 488 {
 489         struct transfer_request *request = request_queue_head;
 490         int num_transfers;
 491
 492         while (active_requests < max_requests && request != NULL) {
 493                 if (request->state == WAITING) {
 494                         if (has_sha1_file(request->sha1))
 495                                 release_request(request);
 496                         else
 497                                 start_request(request);
 498                         curl_multi_perform(curlm, &num_transfers);
 499                 }
 500                 request = request->next;
 501         }
 502 }
 503 #endif
 504
 505 void prefetch(unsigned char *sha1)
 506 {
 507         struct transfer_request *newreq;
 508         struct transfer_request *tail;
 509         char *filename = sha1_file_name(sha1);
 510
 511         newreq = xmalloc(sizeof(*newreq));
 512         memcpy(newreq->sha1, sha1, 20);
 513         newreq->repo = alt;
 514         newreq->url = NULL;
 515         newreq->local = -1;
 516         newreq->state = WAITING;
 517         snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 518         snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 519                  "%s.temp", filename);
 520         newreq->next = NULL;
 521
 522         if (request_queue_head == NULL) {
 523                 request_queue_head = newreq;
 524         } else {
 525                 tail = request_queue_head;
 526                 while (tail->next != NULL) {
 527                         tail = tail->next;
 528                 }
 529                 tail->next = newreq;
 530         }
 531 #ifdef USE_CURL_MULTI
 532         process_request_queue();
 533         process_curl_messages();
 534 #endif
 535 }
 536
 537 static int got_alternates = 0;
 538
 539 static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 540 {
 541         char *hex = sha1_to_hex(sha1);
 542         char *filename;
 543         char *url;
 544         char tmpfile[PATH_MAX];
 545         int ret;
 546         long prev_posn = 0;
 547         char range[RANGE_HEADER_SIZE];
 548         struct curl_slist *range_header = NULL;
 549
 550         FILE *indexfile;
 551         struct active_request_slot *slot;
 552
 553         if (has_pack_index(sha1))
 554                 return 0;
 555
 556         if (get_verbosely)
 557                 fprintf(stderr, "Getting index for pack %s\n", hex);
 558
 559         url = xmalloc(strlen(repo->base) + 64);
 560         sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 561
 562         filename = sha1_pack_index_name(sha1);
 563         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 564         indexfile = fopen(tmpfile, "a");
 565         if (!indexfile)
 566                 return error("Unable to open local file %s for pack index",
 567                              filename);
 568
 569         slot = get_active_slot();
 570         curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 571         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 572         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 573         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 574         slot->local = indexfile;
 575
 576         /* If there is data present from a previous transfer attempt,
 577            resume where it left off */
 578         prev_posn = ftell(indexfile);
 579         if (prev_posn>0) {
 580                 if (get_verbosely)
 581                         fprintf(stderr,
 582                                 "Resuming fetch of index for pack %s at byte %ld\n",
 583                                 hex, prev_posn);
 584                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 585                 range_header = curl_slist_append(range_header, range);
 586                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 587         }
 588
 589         if (start_active_slot(slot)) {
 590                 run_active_slot(slot);
 591                 if (slot->curl_result != CURLE_OK) {
 592                         fclose(indexfile);
 593                         return error("Unable to get pack index %s\n%s", url,
 594                                      curl_errorstr);
 595                 }
 596         } else {
 597                 return error("Unable to start request");
 598         }
 599
 600         fclose(indexfile);
 601
 602         ret = relink_or_rename(tmpfile, filename);
 603         if (ret)
 604                 return error("unable to write index filename %s: %s",
 605                              filename, strerror(ret));
 606
 607         return 0;
 608 }
 609
 610 static int setup_index(struct alt_base *repo, unsigned char *sha1)
 611 {
 612         struct packed_git *new_pack;
 613         if (has_pack_file(sha1))
 614                 return 0; // don't list this as something we can get
 615
 616         if (fetch_index(repo, sha1))
 617                 return -1;
 618
 619         new_pack = parse_pack_index(sha1);
 620         new_pack->next = repo->packs;
 621         repo->packs = new_pack;
 622         return 0;
 623 }
 624
 625 static int fetch_alternates(char *base)
 626 {
 627         int ret = 0;
 628         struct buffer buffer;
 629         char *url;
 630         char *data;
 631         int i = 0;
 632         int http_specific = 1;
 633         struct alt_base *tail = alt;
 634
 635         struct active_request_slot *slot;
 636         if (got_alternates)
 637                 return 0;
 638         data = xmalloc(4096);
 639         buffer.size = 4095;
 640         buffer.posn = 0;
 641         buffer.buffer = data;
 642
 643         if (get_verbosely)
 644                 fprintf(stderr, "Getting alternates list\n");
 645
 646         url = xmalloc(strlen(base) + 31);
 647         sprintf(url, "%s/objects/info/http-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, fwrite_buffer);
 652         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 653         if (start_active_slot(slot)) {
 654                 run_active_slot(slot);
 655                 if (slot->curl_result != CURLE_OK || !buffer.posn) {
 656                         http_specific = 0;
 657
 658                         sprintf(url, "%s/objects/info/alternates", base);
 659
 660                         slot = get_active_slot();
 661                         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 662                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 663                                          fwrite_buffer);
 664                         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 665                         if (start_active_slot(slot)) {
 666                                 run_active_slot(slot);
 667                                 if (slot->curl_result != CURLE_OK) {
 668                                         return 0;
 669                                 }
 670                         }
 671                 }
 672         } else {
 673                 return 0;
 674         }
 675
 676         data[buffer.posn] = '\0';
 677
 678         while (i < buffer.posn) {
 679                 int posn = i;
 680                 while (posn < buffer.posn && data[posn] != '\n')
 681                         posn++;
 682                 if (data[posn] == '\n') {
 683                         int okay = 0;
 684                         int serverlen = 0;
 685                         struct alt_base *newalt;
 686                         char *target = NULL;
 687                         if (data[i] == '/') {
 688                                 serverlen = strchr(base + 8, '/') - base;
 689                                 okay = 1;
 690                         } else if (!memcmp(data + i, "../", 3)) {
 691                                 i += 3;
 692                                 serverlen = strlen(base);
 693                                 while (i + 2 < posn &&
 694                                        !memcmp(data + i, "../", 3)) {
 695                                         do {
 696                                                 serverlen--;
 697                                         } while (serverlen &&
 698                                                  base[serverlen - 1] != '/');
 699                                         i += 3;
 700                                 }
 701                                 // If the server got removed, give up.
 702                                 okay = strchr(base, ':') - base + 3 <
 703                                         serverlen;
 704                         } else if (http_specific) {
 705                                 char *colon = strchr(data + i, ':');
 706                                 char *slash = strchr(data + i, '/');
 707                                 if (colon && slash && colon < data + posn &&
 708                                     slash < data + posn && colon < slash) {
 709                                         okay = 1;
 710                                 }
 711                         }
 712                         // skip 'objects' at end
 713                         if (okay) {
 714                                 target = xmalloc(serverlen + posn - i - 6);
 715                                 strncpy(target, base, serverlen);
 716                                 strncpy(target + serverlen, data + i,
 717                                         posn - i - 7);
 718                                 target[serverlen + posn - i - 7] = '\0';
 719                                 if (get_verbosely)
 720                                         fprintf(stderr,
 721                                                 "Also look at %s\n", target);
 722                                 newalt = xmalloc(sizeof(*newalt));
 723                                 newalt->next = NULL;
 724                                 newalt->base = target;
 725                                 newalt->got_indices = 0;
 726                                 newalt->packs = NULL;
 727                                 while (tail->next != NULL)
 728                                         tail = tail->next;
 729                                 tail->next = newalt;
 730                                 ret++;
 731                         }
 732                 }
 733                 i = posn + 1;
 734         }
 735         got_alternates = 1;
 736
 737         return ret;
 738 }
 739
 740 static int fetch_indices(struct alt_base *repo)
 741 {
 742         unsigned char sha1[20];
 743         char *url;
 744         struct buffer buffer;
 745         char *data;
 746         int i = 0;
 747
 748         struct active_request_slot *slot;
 749
 750         if (repo->got_indices)
 751                 return 0;
 752
 753         data = xmalloc(4096);
 754         buffer.size = 4096;
 755         buffer.posn = 0;
 756         buffer.buffer = data;
 757
 758         if (get_verbosely)
 759                 fprintf(stderr, "Getting pack list\n");
 760
 761         url = xmalloc(strlen(repo->base) + 21);
 762         sprintf(url, "%s/objects/info/packs", repo->base);
 763
 764         slot = get_active_slot();
 765         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 766         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 767         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 768         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 769         if (start_active_slot(slot)) {
 770                 run_active_slot(slot);
 771                 if (slot->curl_result != CURLE_OK)
 772                         return error("%s", curl_errorstr);
 773         } else {
 774                 return error("Unable to start request");
 775         }
 776
 777         while (i < buffer.posn) {
 778                 switch (data[i]) {
 779                 case 'P':
 780                         i++;
 781                         if (i + 52 < buffer.posn &&
 782                             !strncmp(data + i, " pack-", 6) &&
 783                             !strncmp(data + i + 46, ".pack\n", 6)) {
 784                                 get_sha1_hex(data + i + 6, sha1);
 785                                 setup_index(repo, sha1);
 786                                 i += 51;
 787                                 break;
 788                         }
 789                 default:
 790                         while (data[i] != '\n')
 791                                 i++;
 792                 }
 793                 i++;
 794         }
 795
 796         repo->got_indices = 1;
 797         return 0;
 798 }
 799
 800 static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 801 {
 802         char *url;
 803         struct packed_git *target;
 804         struct packed_git **lst;
 805         FILE *packfile;
 806         char *filename;
 807         char tmpfile[PATH_MAX];
 808         int ret;
 809         long prev_posn = 0;
 810         char range[RANGE_HEADER_SIZE];
 811         struct curl_slist *range_header = NULL;
 812
 813         struct active_request_slot *slot;
 814
 815         if (fetch_indices(repo))
 816                 return -1;
 817         target = find_sha1_pack(sha1, repo->packs);
 818         if (!target)
 819                 return -1;
 820
 821         if (get_verbosely) {
 822                 fprintf(stderr, "Getting pack %s\n",
 823                         sha1_to_hex(target->sha1));
 824                 fprintf(stderr, " which contains %s\n",
 825                         sha1_to_hex(sha1));
 826         }
 827
 828         url = xmalloc(strlen(repo->base) + 65);
 829         sprintf(url, "%s/objects/pack/pack-%s.pack",
 830                 repo->base, sha1_to_hex(target->sha1));
 831
 832         filename = sha1_pack_name(target->sha1);
 833         snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 834         packfile = fopen(tmpfile, "a");
 835         if (!packfile)
 836                 return error("Unable to open local file %s for pack",
 837                              filename);
 838
 839         slot = get_active_slot();
 840         curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 841         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 842         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 843         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 844         slot->local = packfile;
 845
 846         /* If there is data present from a previous transfer attempt,
 847            resume where it left off */
 848         prev_posn = ftell(packfile);
 849         if (prev_posn>0) {
 850                 if (get_verbosely)
 851                         fprintf(stderr,
 852                                 "Resuming fetch of pack %s at byte %ld\n",
 853                                 sha1_to_hex(target->sha1), prev_posn);
 854                 sprintf(range, "Range: bytes=%ld-", prev_posn);
 855                 range_header = curl_slist_append(range_header, range);
 856                 curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 857         }
 858
 859         if (start_active_slot(slot)) {
 860                 run_active_slot(slot);
 861                 if (slot->curl_result != CURLE_OK) {
 862                         fclose(packfile);
 863                         return error("Unable to get pack file %s\n%s", url,
 864                                      curl_errorstr);
 865                 }
 866         } else {
 867                 return error("Unable to start request");
 868         }
 869
 870         fclose(packfile);
 871
 872         ret = relink_or_rename(tmpfile, filename);
 873         if (ret)
 874                 return error("unable to write pack filename %s: %s",
 875                              filename, strerror(ret));
 876
 877         lst = &repo->packs;
 878         while (*lst != target)
 879                 lst = &((*lst)->next);
 880         *lst = (*lst)->next;
 881
 882         if (verify_pack(target, 0))
 883                 return -1;
 884         install_packed_git(target);
 885
 886         return 0;
 887 }
 888
 889 static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 890 {
 891         char *hex = sha1_to_hex(sha1);
 892         int ret;
 893         struct transfer_request *request = request_queue_head;
 894
 895         while (request != NULL && memcmp(request->sha1, sha1, 20))
 896                 request = request->next;
 897         if (request == NULL)
 898                 return error("Couldn't find request for %s in the queue", hex);
 899
 900         if (has_sha1_file(request->sha1)) {
 901                 release_request(request);
 902                 return 0;
 903         }
 904
 905 #ifdef USE_CURL_MULTI
 906         int num_transfers;
 907         while (request->state == WAITING) {
 908                 curl_multi_perform(curlm, &num_transfers);
 909                 if (num_transfers < active_requests) {
 910                         process_curl_messages();
 911                         process_request_queue();
 912                 }
 913         }
 914 #else
 915         start_request(request);
 916 #endif
 917
 918         while (request->state == ACTIVE) {
 919                 run_active_slot(request->slot);
 920 #ifndef USE_CURL_MULTI
 921                 request->curl_result = request->slot->curl_result;
 922                 curl_easy_getinfo(request->slot->curl,
 923                                   CURLINFO_HTTP_CODE,
 924                                   &request->http_code);
 925                 request->slot = NULL;
 926
 927                 /* Use alternates if necessary */
 928                 if (request->http_code == 404 &&
 929                     request->repo->next != NULL) {
 930                         request->repo = request->repo->next;
 931                         start_request(request);
 932                 } else {
 933                         finish_request(request);
 934                         request->state = COMPLETE;
 935                 }
 936 #endif
 937         }
 938
 939         if (request->state == ABORTED) {
 940                 release_request(request);
 941                 return error("Request for %s aborted", hex);
 942         }
 943
 944         if (request->curl_result != CURLE_OK && request->http_code != 416) {
 945                 ret = error("%s", request->errorstr);
 946                 release_request(request);
 947                 return ret;
 948         }
 949
 950         if (request->zret != Z_STREAM_END) {
 951                 ret = error("File %s (%s) corrupt\n", hex, request->url);
 952                 release_request(request);
 953                 return ret;
 954         }
 955
 956         if (memcmp(request->sha1, request->real_sha1, 20)) {
 957                 release_request(request);
 958                 return error("File %s has bad hash\n", hex);
 959         }
 960
 961         if (request->rename < 0) {
 962                 ret = error("unable to write sha1 filename %s: %s",
 963                             request->filename,
 964                             strerror(request->rename));
 965                 release_request(request);
 966                 return ret;
 967         }
 968
 969         release_request(request);
 970         return 0;
 971 }
 972
 973 int fetch(unsigned char *sha1)
 974 {
 975         struct alt_base *altbase = alt;
 976
 977         if (!fetch_object(altbase, sha1))
 978                 return 0;
 979         while (altbase) {
 980                 if (!fetch_pack(altbase, sha1))
 981                         return 0;
 982                 altbase = altbase->next;
 983         }
 984         return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
 985                      alt->base);
 986 }
 987
 988 int fetch_ref(char *ref, unsigned char *sha1)
 989 {
 990         char *url, *posn;
 991         char hex[42];
 992         struct buffer buffer;
 993         char *base = alt->base;
 994         struct active_request_slot *slot;
 995         buffer.size = 41;
 996         buffer.posn = 0;
 997         buffer.buffer = hex;
 998         hex[41] = '\0';
 999
1000         url = xmalloc(strlen(base) + 6 + strlen(ref));
1001         strcpy(url, base);
1002         posn = url + strlen(base);
1003         strcpy(posn, "refs/");
1004         posn += 5;
1005         strcpy(posn, ref);
1006
1007         slot = get_active_slot();
1008         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
1009         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
1010         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
1011         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1012         if (start_active_slot(slot)) {
1013                 run_active_slot(slot);
1014                 if (slot->curl_result != CURLE_OK)
1015                         return error("Couldn't get %s for %s\n%s",
1016                                      url, ref, curl_errorstr);
1017         } else {
1018                 return error("Unable to start request");
1019         }
1020
1021         hex[40] = '\0';
1022         get_sha1_hex(hex, sha1);
1023         return 0;
1024 }
1025
1026 int main(int argc, char **argv)
1027 {
1028         char *commit_id;
1029         char *url;
1030         int arg = 1;
1031         struct active_request_slot *slot;
1032
1033         while (arg < argc && argv[arg][0] == '-') {
1034                 if (argv[arg][1] == 't') {
1035                         get_tree = 1;
1036                 } else if (argv[arg][1] == 'c') {
1037                         get_history = 1;
1038                 } else if (argv[arg][1] == 'a') {
1039                         get_all = 1;
1040                         get_tree = 1;
1041                         get_history = 1;
1042                 } else if (argv[arg][1] == 'v') {
1043                         get_verbosely = 1;
1044                 } else if (argv[arg][1] == 'w') {
1045                         write_ref = argv[arg + 1];
1046                         arg++;
1047                 } else if (!strcmp(argv[arg], "--recover")) {
1048                         get_recover = 1;
1049                 }
1050                 arg++;
1051         }
1052         if (argc < arg + 2) {
1053                 usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1054                 return 1;
1055         }
1056         commit_id = argv[arg];
1057         url = argv[arg + 1];
1058
1059         curl_global_init(CURL_GLOBAL_ALL);
1060
1061 #ifdef USE_CURL_MULTI
1062         char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1063         if (http_max_requests != NULL)
1064                 max_requests = atoi(http_max_requests);
1065         if (max_requests < 1)
1066                 max_requests = DEFAULT_MAX_REQUESTS;
1067
1068         curlm = curl_multi_init();
1069         if (curlm == NULL) {
1070                 fprintf(stderr, "Error creating curl multi handle.\n");
1071                 return 1;
1072         }
1073 #endif
1074         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
1075         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1076         no_range_header = curl_slist_append(no_range_header, "Range:");
1077
1078         curl_default = curl_easy_init();
1079
1080         curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
1081         curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1082 #if LIBCURL_VERSION_NUM >= 0x070907
1083         curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1084 #endif
1085
1086         if ((ssl_cert = getenv("GIT_SSL_CERT")) != NULL) {
1087                 curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1088         }
1089 #if LIBCURL_VERSION_NUM >= 0x070902
1090         if ((ssl_key = getenv("GIT_SSL_KEY")) != NULL) {
1091                 curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1092         }
1093 #endif
1094 #if LIBCURL_VERSION_NUM >= 0x070908
1095         if ((ssl_capath = getenv("GIT_SSL_CAPATH")) != NULL) {
1096                 curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1097         }
1098 #endif
1099         if ((ssl_cainfo = getenv("GIT_SSL_CAINFO")) != NULL) {
1100                 curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1101         }
1102         curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1103
1104         alt = xmalloc(sizeof(*alt));
1105         alt->base = url;
1106         alt->got_indices = 0;
1107         alt->packs = NULL;
1108         alt->next = NULL;
1109         fetch_alternates(alt->base);
1110
1111         if (pull(commit_id))
1112                 return 1;
1113
1114         curl_slist_free_all(pragma_header);
1115         curl_slist_free_all(no_pragma_header);
1116         curl_slist_free_all(no_range_header);
1117         curl_easy_cleanup(curl_default);
1118         slot = active_queue_head;
1119         while (slot != NULL) {
1120                 curl_easy_cleanup(slot->curl);
1121                 slot = slot->next;
1122         }
1123 #ifdef USE_CURL_MULTI
1124         curl_multi_cleanup(curlm);
1125 #endif
1126         curl_global_cleanup();
1127         return 0;
1128 }