Andrew's git - gitweb.git/blob

dd9ea4ca17d83f3267c4d9d7fe04b5e49a19cff2
   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
  24static int active_requests = 0;
  25static int data_received;
  26
  27#ifdef USE_CURL_MULTI
  28static int max_requests = DEFAULT_MAX_REQUESTS;
  29static CURLM *curlm;
  30#endif
  31static CURL *curl_default;
  32static struct curl_slist *no_pragma_header;
  33static struct curl_slist *no_range_header;
  34static char curl_errorstr[CURL_ERROR_SIZE];
  35
  36struct alt_base
  37{
  38        char *base;
  39        int got_indices;
  40        struct packed_git *packs;
  41        struct alt_base *next;
  42};
  43
  44static struct alt_base *alt = NULL;
  45
  46enum transfer_state {
  47        WAITING,
  48        ABORTED,
  49        ACTIVE,
  50        COMPLETE,
  51};
  52
  53struct transfer_request
  54{
  55        unsigned char sha1[20];
  56        struct alt_base *repo;
  57        char *url;
  58        char filename[PATH_MAX];
  59        char tmpfile[PATH_MAX];
  60        int local;
  61        enum transfer_state state;
  62        CURLcode curl_result;
  63        char errorstr[CURL_ERROR_SIZE];
  64        long http_code;
  65        unsigned char real_sha1[20];
  66        SHA_CTX c;
  67        z_stream stream;
  68        int zret;
  69        int rename;
  70        struct active_request_slot *slot;
  71        struct transfer_request *next;
  72};
  73
  74struct active_request_slot
  75{
  76        CURL *curl;
  77        FILE *local;
  78        int in_use;
  79        int done;
  80        CURLcode curl_result;
  81        struct active_request_slot *next;
  82};
  83
  84static struct transfer_request *request_queue_head = NULL;
  85static struct active_request_slot *active_queue_head = NULL;
  86
  87static int curl_ssl_verify;
  88static char *ssl_cert;
  89static char *ssl_key;
  90static char *ssl_capath;
  91static char *ssl_cainfo;
  92
  93struct buffer
  94{
  95        size_t posn;
  96        size_t size;
  97        void *buffer;
  98};
  99
 100static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
 101                            struct buffer *buffer)
 102{
 103        size_t size = eltsize * nmemb;
 104        if (size > buffer->size - buffer->posn)
 105                size = buffer->size - buffer->posn;
 106        memcpy(buffer->buffer + buffer->posn, ptr, size);
 107        buffer->posn += size;
 108        data_received++;
 109        return size;
 110}
 111
 112static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 113                               void *data)
 114{
 115        unsigned char expn[4096];
 116        size_t size = eltsize * nmemb;
 117        int posn = 0;
 118        struct transfer_request *request = (struct transfer_request *)data;
 119        do {
 120                ssize_t retval = write(request->local,
 121                                       ptr + posn, size - posn);
 122                if (retval < 0)
 123                        return posn;
 124                posn += retval;
 125        } while (posn < size);
 126
 127        request->stream.avail_in = size;
 128        request->stream.next_in = ptr;
 129        do {
 130                request->stream.next_out = expn;
 131                request->stream.avail_out = sizeof(expn);
 132                request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
 133                SHA1_Update(&request->c, expn,
 134                            sizeof(expn) - request->stream.avail_out);
 135        } while (request->stream.avail_in && request->zret == Z_OK);
 136        data_received++;
 137        return size;
 138}
 139
 140int relink_or_rename(char *old, char *new) {
 141        int ret;
 142
 143        ret = link(old, new);
 144        if (ret < 0) {
 145                /* Same Coda hack as in write_sha1_file(sha1_file.c) */
 146                ret = errno;
 147                if (ret == EXDEV && !rename(old, new))
 148                        return 0;
 149        }
 150        unlink(old);
 151        if (ret) {
 152                if (ret != EEXIST)
 153                        return ret;
 154        }
 155
 156        return 0;
 157}
 158
 159#ifdef USE_CURL_MULTI
 160void process_curl_messages();
 161void process_request_queue();
 162#endif
 163
 164struct active_request_slot *get_active_slot()
 165{
 166        struct active_request_slot *slot = active_queue_head;
 167        struct active_request_slot *newslot;
 168
 169#ifdef USE_CURL_MULTI
 170        int num_transfers;
 171
 172        /* Wait for a slot to open up if the queue is full */
 173        while (active_requests >= max_requests) {
 174                curl_multi_perform(curlm, &num_transfers);
 175                if (num_transfers < active_requests) {
 176                        process_curl_messages();
 177                }
 178        }
 179#endif
 180
 181        while (slot != NULL && slot->in_use) {
 182                slot = slot->next;
 183        }
 184        if (slot == NULL) {
 185                newslot = xmalloc(sizeof(*newslot));
 186                newslot->curl = curl_easy_duphandle(curl_default);
 187                newslot->in_use = 0;
 188                newslot->next = NULL;
 189
 190                slot = active_queue_head;
 191                if (slot == NULL) {
 192                        active_queue_head = newslot;
 193                } else {
 194                        while (slot->next != NULL) {
 195                                slot = slot->next;
 196                        }
 197                        slot->next = newslot;
 198                }
 199                slot = newslot;
 200        }
 201
 202        active_requests++;
 203        slot->in_use = 1;
 204        slot->done = 0;
 205        slot->local = NULL;
 206        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 207        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 208        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 209
 210        return slot;
 211}
 212
 213int start_active_slot(struct active_request_slot *slot)
 214{
 215#ifdef USE_CURL_MULTI
 216        CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 217
 218        if (curlm_result != CURLM_OK &&
 219            curlm_result != CURLM_CALL_MULTI_PERFORM) {
 220                active_requests--;
 221                slot->in_use = 0;
 222                return 0;
 223        }
 224#endif
 225        return 1;
 226}
 227
 228void run_active_slot(struct active_request_slot *slot)
 229{
 230#ifdef USE_CURL_MULTI
 231        int num_transfers;
 232        long last_pos = 0;
 233        long current_pos;
 234        fd_set readfds;
 235        fd_set writefds;
 236        fd_set excfds;
 237        int max_fd;
 238        struct timeval select_timeout;
 239        CURLMcode curlm_result;
 240
 241        while (!slot->done) {
 242                data_received = 0;
 243                do {
 244                        curlm_result = curl_multi_perform(curlm,
 245                                                          &num_transfers);
 246                } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 247                if (num_transfers < active_requests) {
 248                        process_curl_messages();
 249                        process_request_queue();
 250                }
 251
 252                if (!data_received && slot->local != NULL) {
 253                        current_pos = ftell(slot->local);
 254                        if (current_pos > last_pos)
 255                                data_received++;
 256                        last_pos = current_pos;
 257                }
 258
 259                if (!slot->done && !data_received) {
 260                        max_fd = 0;
 261                        FD_ZERO(&readfds);
 262                        FD_ZERO(&writefds);
 263                        FD_ZERO(&excfds);
 264                        select_timeout.tv_sec = 0;
 265                        select_timeout.tv_usec = 50000;
 266                        select(max_fd, &readfds, &writefds,
 267                               &excfds, &select_timeout);
 268                }
 269        }
 270#else
 271        slot->curl_result = curl_easy_perform(slot->curl);
 272        active_requests--;
 273#endif
 274}
 275
 276void start_request(struct transfer_request *request)
 277{
 278        char *hex = sha1_to_hex(request->sha1);
 279        char prevfile[PATH_MAX];
 280        char *url;
 281        char *posn;
 282        int prevlocal;
 283        unsigned char prev_buf[PREV_BUF_SIZE];
 284        ssize_t prev_read = 0;
 285        long prev_posn = 0;
 286        char range[RANGE_HEADER_SIZE];
 287        struct curl_slist *range_header = NULL;
 288        struct active_request_slot *slot;
 289
 290        snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 291        unlink(prevfile);
 292        rename(request->tmpfile, prevfile);
 293        unlink(request->tmpfile);
 294
 295        request->local = open(request->tmpfile,
 296                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 297        if (request->local < 0) {
 298                request->state = ABORTED;
 299                error("Couldn't create temporary file %s for %s: %s\n",
 300                      request->tmpfile, request->filename, strerror(errno));
 301                return;
 302        }
 303
 304        memset(&request->stream, 0, sizeof(request->stream));
 305
 306        inflateInit(&request->stream);
 307
 308        SHA1_Init(&request->c);
 309
 310        url = xmalloc(strlen(request->repo->base) + 50);
 311        request->url = xmalloc(strlen(request->repo->base) + 50);
 312        strcpy(url, request->repo->base);
 313        posn = url + strlen(request->repo->base);
 314        strcpy(posn, "objects/");
 315        posn += 8;
 316        memcpy(posn, hex, 2);
 317        posn += 2;
 318        *(posn++) = '/';
 319        strcpy(posn, hex + 2);
 320        strcpy(request->url, url);
 321
 322        /* If a previous temp file is present, process what was already
 323           fetched. */
 324        prevlocal = open(prevfile, O_RDONLY);
 325        if (prevlocal != -1) {
 326                do {
 327                        prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 328                        if (prev_read>0) {
 329                                if (fwrite_sha1_file(prev_buf,
 330                                                     1,
 331                                                     prev_read,
 332                                                     request) == prev_read) {
 333                                        prev_posn += prev_read;
 334                                } else {
 335                                        prev_read = -1;
 336                                }
 337                        }
 338                } while (prev_read > 0);
 339                close(prevlocal);
 340        }
 341        unlink(prevfile);
 342
 343        /* Reset inflate/SHA1 if there was an error reading the previous temp
 344           file; also rewind to the beginning of the local file. */
 345        if (prev_read == -1) {
 346                memset(&request->stream, 0, sizeof(request->stream));
 347                inflateInit(&request->stream);
 348                SHA1_Init(&request->c);
 349                if (prev_posn>0) {
 350                        prev_posn = 0;
 351                        lseek(request->local, SEEK_SET, 0);
 352                        ftruncate(request->local, 0);
 353                }
 354        }
 355
 356        slot = get_active_slot();
 357        curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 358        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 359        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 360        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 361
 362        /* If we have successfully processed data from a previous fetch
 363           attempt, only fetch the data we don't already have. */
 364        if (prev_posn>0) {
 365                if (get_verbosely)
 366                        fprintf(stderr,
 367                                "Resuming fetch of object %s at byte %ld\n",
 368                                hex, prev_posn);
 369                sprintf(range, "Range: bytes=%ld-", prev_posn);
 370                range_header = curl_slist_append(range_header, range);
 371                curl_easy_setopt(slot->curl,
 372                                 CURLOPT_HTTPHEADER, range_header);
 373        }
 374
 375        /* Try to get the request started, abort the request on error */
 376        if (!start_active_slot(slot)) {
 377                request->state = ABORTED;
 378                close(request->local);
 379                free(request->url);
 380                return;
 381        }
 382        
 383        request->slot = slot;
 384        request->state = ACTIVE;
 385}
 386
 387void finish_request(struct transfer_request *request)
 388{
 389        fchmod(request->local, 0444);
 390        close(request->local);
 391
 392        if (request->http_code == 416) {
 393                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 394        } else if (request->curl_result != CURLE_OK) {
 395                return;
 396        }
 397
 398        inflateEnd(&request->stream);
 399        SHA1_Final(request->real_sha1, &request->c);
 400        if (request->zret != Z_STREAM_END) {
 401                unlink(request->tmpfile);
 402                return;
 403        }
 404        if (memcmp(request->sha1, request->real_sha1, 20)) {
 405                unlink(request->tmpfile);
 406                return;
 407        }
 408        request->rename =
 409                relink_or_rename(request->tmpfile, request->filename);
 410
 411        if (request->rename == 0)
 412                pull_say("got %s\n", sha1_to_hex(request->sha1));
 413}
 414
 415void release_request(struct transfer_request *request)
 416{
 417        struct transfer_request *entry = request_queue_head;
 418
 419        if (request == request_queue_head) {
 420                request_queue_head = request->next;
 421        } else {
 422                while (entry->next != NULL && entry->next != request)
 423                        entry = entry->next;
 424                if (entry->next == request)
 425                        entry->next = entry->next->next;
 426        }
 427
 428        free(request->url);
 429        free(request);
 430}
 431
 432#ifdef USE_CURL_MULTI
 433void process_curl_messages()
 434{
 435        int num_messages;
 436        struct active_request_slot *slot;
 437        struct transfer_request *request = NULL;
 438        CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 439
 440        while (curl_message != NULL) {
 441                if (curl_message->msg == CURLMSG_DONE) {
 442                        slot = active_queue_head;
 443                        while (slot != NULL &&
 444                               slot->curl != curl_message->easy_handle)
 445                                slot = slot->next;
 446                        if (slot != NULL) {
 447                                curl_multi_remove_handle(curlm, slot->curl);
 448                                active_requests--;
 449                                slot->done = 1;
 450                                slot->in_use = 0;
 451                                slot->curl_result = curl_message->data.result;
 452                                request = request_queue_head;
 453                                while (request != NULL &&
 454                                       request->slot != slot)
 455                                        request = request->next;
 456                        } else {
 457                                fprintf(stderr, "Received DONE message for unknown request!\n");
 458                        }
 459                        if (request != NULL) {
 460                                request->curl_result =
 461                                        curl_message->data.result;
 462                                curl_easy_getinfo(slot->curl,
 463                                                  CURLINFO_HTTP_CODE,
 464                                                  &request->http_code);
 465                                request->slot = NULL;
 466
 467                                /* Use alternates if necessary */
 468                                if (request->http_code == 404 &&
 469                                    request->repo->next != NULL) {
 470                                        request->repo = request->repo->next;
 471                                        start_request(request);
 472                                } else {
 473                                        finish_request(request);
 474                                        request->state = COMPLETE;
 475                                }
 476                        }
 477                } else {
 478                        fprintf(stderr, "Unknown CURL message received: %d\n",
 479                                (int)curl_message->msg);
 480                }
 481                curl_message = curl_multi_info_read(curlm, &num_messages);
 482        }
 483}
 484
 485void process_request_queue()
 486{
 487        struct transfer_request *request = request_queue_head;
 488        int num_transfers;
 489
 490        while (active_requests < max_requests && request != NULL) {
 491                if (request->state == WAITING) {
 492                        start_request(request);
 493                        curl_multi_perform(curlm, &num_transfers);
 494                }
 495                request = request->next;
 496        }
 497}
 498#endif
 499
 500void 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
 532static int got_alternates = 0;
 533
 534static 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        int ret;
 541        long prev_posn = 0;
 542        char range[RANGE_HEADER_SIZE];
 543        struct curl_slist *range_header = NULL;
 544
 545        FILE *indexfile;
 546        struct active_request_slot *slot;
 547
 548        if (has_pack_index(sha1))
 549                return 0;
 550
 551        if (get_verbosely)
 552                fprintf(stderr, "Getting index for pack %s\n", hex);
 553        
 554        url = xmalloc(strlen(repo->base) + 64);
 555        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 556        
 557        filename = sha1_pack_index_name(sha1);
 558        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 559        indexfile = fopen(tmpfile, "a");
 560        if (!indexfile)
 561                return error("Unable to open local file %s for pack index",
 562                             filename);
 563
 564        slot = get_active_slot();
 565        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 566        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 567        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 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        ret = relink_or_rename(tmpfile, filename);
 597        if (ret)
 598                return error("unable to write index filename %s: %s",
 599                             filename, strerror(ret));
 600
 601        return 0;
 602}
 603
 604static int setup_index(struct alt_base *repo, unsigned char *sha1)
 605{
 606        struct packed_git *new_pack;
 607        if (has_pack_file(sha1))
 608                return 0; // don't list this as something we can get
 609
 610        if (fetch_index(repo, sha1))
 611                return -1;
 612
 613        new_pack = parse_pack_index(sha1);
 614        new_pack->next = repo->packs;
 615        repo->packs = new_pack;
 616        return 0;
 617}
 618
 619static int fetch_alternates(char *base)
 620{
 621        int ret = 0;
 622        struct buffer buffer;
 623        char *url;
 624        char *data;
 625        int i = 0;
 626        int http_specific = 1;
 627        struct alt_base *tail = alt;
 628
 629        struct active_request_slot *slot;
 630        if (got_alternates)
 631                return 0;
 632        data = xmalloc(4096);
 633        buffer.size = 4095;
 634        buffer.posn = 0;
 635        buffer.buffer = data;
 636
 637        if (get_verbosely)
 638                fprintf(stderr, "Getting alternates list\n");
 639        
 640        url = xmalloc(strlen(base) + 31);
 641        sprintf(url, "%s/objects/info/http-alternates", base);
 642
 643        slot = get_active_slot();
 644        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 645        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 646        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 647        if (start_active_slot(slot)) {
 648                run_active_slot(slot);
 649                if (slot->curl_result != CURLE_OK || !buffer.posn) {
 650                        http_specific = 0;
 651
 652                        sprintf(url, "%s/objects/info/alternates", base);
 653
 654                        slot = get_active_slot();
 655                        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 656                        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 657                                         fwrite_buffer);
 658                        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 659                        if (start_active_slot(slot)) {
 660                                run_active_slot(slot);
 661                                if (slot->curl_result != CURLE_OK) {
 662                                        return 0;
 663                                }
 664                        }
 665                }
 666        } else {
 667                return 0;
 668        }
 669
 670        data[buffer.posn] = '\0';
 671
 672        while (i < buffer.posn) {
 673                int posn = i;
 674                while (posn < buffer.posn && data[posn] != '\n')
 675                        posn++;
 676                if (data[posn] == '\n') {
 677                        int okay = 0;
 678                        int serverlen = 0;
 679                        struct alt_base *newalt;
 680                        char *target = NULL;
 681                        if (data[i] == '/') {
 682                                serverlen = strchr(base + 8, '/') - base;
 683                                okay = 1;
 684                        } else if (!memcmp(data + i, "../", 3)) {
 685                                i += 3;
 686                                serverlen = strlen(base);
 687                                while (i + 2 < posn && 
 688                                       !memcmp(data + i, "../", 3)) {
 689                                        do {
 690                                                serverlen--;
 691                                        } while (serverlen &&
 692                                                 base[serverlen - 1] != '/');
 693                                        i += 3;
 694                                }
 695                                // If the server got removed, give up.
 696                                okay = strchr(base, ':') - base + 3 < 
 697                                        serverlen;
 698                        } else if (http_specific) {
 699                                char *colon = strchr(data + i, ':');
 700                                char *slash = strchr(data + i, '/');
 701                                if (colon && slash && colon < data + posn &&
 702                                    slash < data + posn && colon < slash) {
 703                                        okay = 1;
 704                                }
 705                        }
 706                        // skip 'objects' at end
 707                        if (okay) {
 708                                target = xmalloc(serverlen + posn - i - 6);
 709                                strncpy(target, base, serverlen);
 710                                strncpy(target + serverlen, data + i,
 711                                        posn - i - 7);
 712                                target[serverlen + posn - i - 7] = '\0';
 713                                if (get_verbosely)
 714                                        fprintf(stderr, 
 715                                                "Also look at %s\n", target);
 716                                newalt = xmalloc(sizeof(*newalt));
 717                                newalt->next = NULL;
 718                                newalt->base = target;
 719                                newalt->got_indices = 0;
 720                                newalt->packs = NULL;
 721                                while (tail->next != NULL)
 722                                        tail = tail->next;
 723                                tail->next = newalt;
 724                                ret++;
 725                        }
 726                }
 727                i = posn + 1;
 728        }
 729        got_alternates = 1;
 730        
 731        return ret;
 732}
 733
 734static int fetch_indices(struct alt_base *repo)
 735{
 736        unsigned char sha1[20];
 737        char *url;
 738        struct buffer buffer;
 739        char *data;
 740        int i = 0;
 741
 742        struct active_request_slot *slot;
 743
 744        if (repo->got_indices)
 745                return 0;
 746
 747        data = xmalloc(4096);
 748        buffer.size = 4096;
 749        buffer.posn = 0;
 750        buffer.buffer = data;
 751
 752        if (get_verbosely)
 753                fprintf(stderr, "Getting pack list\n");
 754        
 755        url = xmalloc(strlen(repo->base) + 21);
 756        sprintf(url, "%s/objects/info/packs", repo->base);
 757
 758        slot = get_active_slot();
 759        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 760        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 761        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 762        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 763        if (start_active_slot(slot)) {
 764                run_active_slot(slot);
 765                if (slot->curl_result != CURLE_OK)
 766                        return error("%s", curl_errorstr);
 767        } else {
 768                return error("Unable to start request");
 769        }
 770
 771        while (i < buffer.posn) {
 772                switch (data[i]) {
 773                case 'P':
 774                        i++;
 775                        if (i + 52 < buffer.posn &&
 776                            !strncmp(data + i, " pack-", 6) &&
 777                            !strncmp(data + i + 46, ".pack\n", 6)) {
 778                                get_sha1_hex(data + i + 6, sha1);
 779                                setup_index(repo, sha1);
 780                                i += 51;
 781                                break;
 782                        }
 783                default:
 784                        while (data[i] != '\n')
 785                                i++;
 786                }
 787                i++;
 788        }
 789
 790        repo->got_indices = 1;
 791        return 0;
 792}
 793
 794static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 795{
 796        char *url;
 797        struct packed_git *target;
 798        struct packed_git **lst;
 799        FILE *packfile;
 800        char *filename;
 801        char tmpfile[PATH_MAX];
 802        int ret;
 803        long prev_posn = 0;
 804        char range[RANGE_HEADER_SIZE];
 805        struct curl_slist *range_header = NULL;
 806
 807        struct active_request_slot *slot;
 808
 809        if (fetch_indices(repo))
 810                return -1;
 811        target = find_sha1_pack(sha1, repo->packs);
 812        if (!target)
 813                return -1;
 814
 815        if (get_verbosely) {
 816                fprintf(stderr, "Getting pack %s\n",
 817                        sha1_to_hex(target->sha1));
 818                fprintf(stderr, " which contains %s\n",
 819                        sha1_to_hex(sha1));
 820        }
 821
 822        url = xmalloc(strlen(repo->base) + 65);
 823        sprintf(url, "%s/objects/pack/pack-%s.pack",
 824                repo->base, sha1_to_hex(target->sha1));
 825
 826        filename = sha1_pack_name(target->sha1);
 827        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 828        packfile = fopen(tmpfile, "a");
 829        if (!packfile)
 830                return error("Unable to open local file %s for pack",
 831                             filename);
 832
 833        slot = get_active_slot();
 834        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 835        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 836        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 837        slot->local = packfile;
 838
 839        /* If there is data present from a previous transfer attempt,
 840           resume where it left off */
 841        prev_posn = ftell(packfile);
 842        if (prev_posn>0) {
 843                if (get_verbosely)
 844                        fprintf(stderr,
 845                                "Resuming fetch of pack %s at byte %ld\n",
 846                                sha1_to_hex(target->sha1), prev_posn);
 847                sprintf(range, "Range: bytes=%ld-", prev_posn);
 848                range_header = curl_slist_append(range_header, range);
 849                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 850        }
 851
 852        if (start_active_slot(slot)) {
 853                run_active_slot(slot);
 854                if (slot->curl_result != CURLE_OK) {
 855                        fclose(packfile);
 856                        return error("Unable to get pack file %s\n%s", url,
 857                                     curl_errorstr);
 858                }
 859        } else {
 860                return error("Unable to start request");
 861        }
 862
 863        fclose(packfile);
 864
 865        ret = relink_or_rename(tmpfile, filename);
 866        if (ret)
 867                return error("unable to write pack filename %s: %s",
 868                             filename, strerror(ret));
 869
 870        lst = &repo->packs;
 871        while (*lst != target)
 872                lst = &((*lst)->next);
 873        *lst = (*lst)->next;
 874
 875        if (verify_pack(target, 0))
 876                return -1;
 877        install_packed_git(target);
 878
 879        return 0;
 880}
 881
 882static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 883{
 884        char *hex = sha1_to_hex(sha1);
 885        int ret;
 886        struct transfer_request *request = request_queue_head;
 887
 888        while (request != NULL && memcmp(request->sha1, sha1, 20))
 889                request = request->next;
 890        if (request == NULL)
 891                return error("Couldn't find request for %s in the queue", hex);
 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
 961int 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
 976int 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
1014int 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        no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1063        no_range_header = curl_slist_append(no_range_header, "Range:");
1064
1065        curl_default = curl_easy_init();
1066
1067        curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
1068        curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1069#if LIBCURL_VERSION_NUM >= 0x070907
1070        curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1071#endif
1072
1073        if ((ssl_cert = getenv("GIT_SSL_CERT")) != NULL) {
1074                curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1075        }
1076#if LIBCURL_VERSION_NUM >= 0x070902
1077        if ((ssl_key = getenv("GIT_SSL_KEY")) != NULL) {
1078                curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1079        }
1080#endif
1081#if LIBCURL_VERSION_NUM >= 0x070908
1082        if ((ssl_capath = getenv("GIT_SSL_CAPATH")) != NULL) {
1083                curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1084        }
1085#endif
1086        if ((ssl_cainfo = getenv("GIT_SSL_CAINFO")) != NULL) {
1087                curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1088        }
1089        curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1090
1091        alt = xmalloc(sizeof(*alt));
1092        alt->base = url;
1093        alt->got_indices = 0;
1094        alt->packs = NULL;
1095        alt->next = NULL;
1096        fetch_alternates(alt->base);
1097
1098        if (pull(commit_id))
1099                return 1;
1100
1101        curl_slist_free_all(no_pragma_header);
1102        curl_slist_free_all(no_range_header);
1103        curl_easy_cleanup(curl_default);
1104        slot = active_queue_head;
1105        while (slot != NULL) {
1106                curl_easy_cleanup(slot->curl);
1107                slot = slot->next;
1108        }
1109#ifdef USE_CURL_MULTI
1110        curl_multi_cleanup(curlm);
1111#endif
1112        curl_global_cleanup();
1113        return 0;
1114}