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