Andrew's git / gitweb.git / http-fetch.c
?
http-fetch.con commit Reference git-commit-tree for env vars. (5bfc4f2)
   1#include "cache.h"
   2#include "commit.h"
   3#include "pack.h"
   4#include "fetch.h"
   5#include "http.h"
   6
   7#define PREV_BUF_SIZE 4096
   8#define RANGE_HEADER_SIZE 30
   9
  10static int got_alternates = -1;
  11
  12static struct curl_slist *no_pragma_header;
  13
  14struct alt_base
  15{
  16        char *base;
  17        int got_indices;
  18        struct packed_git *packs;
  19        struct alt_base *next;
  20};
  21
  22static struct alt_base *alt = NULL;
  23
  24enum object_request_state {
  25        WAITING,
  26        ABORTED,
  27        ACTIVE,
  28        COMPLETE,
  29};
  30
  31struct object_request
  32{
  33        unsigned char sha1[20];
  34        struct alt_base *repo;
  35        char *url;
  36        char filename[PATH_MAX];
  37        char tmpfile[PATH_MAX];
  38        int local;
  39        enum object_request_state state;
  40        CURLcode curl_result;
  41        char errorstr[CURL_ERROR_SIZE];
  42        long http_code;
  43        unsigned char real_sha1[20];
  44        SHA_CTX c;
  45        z_stream stream;
  46        int zret;
  47        int rename;
  48        struct active_request_slot *slot;
  49        struct object_request *next;
  50};
  51
  52struct alternates_request {
  53        char *base;
  54        char *url;
  55        struct buffer *buffer;
  56        struct active_request_slot *slot;
  57        int http_specific;
  58};
  59
  60static struct object_request *object_queue_head = NULL;
  61
  62static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
  63                               void *data)
  64{
  65        unsigned char expn[4096];
  66        size_t size = eltsize * nmemb;
  67        int posn = 0;
  68        struct object_request *obj_req = (struct object_request *)data;
  69        do {
  70                ssize_t retval = write(obj_req->local,
  71                                       ptr + posn, size - posn);
  72                if (retval < 0)
  73                        return posn;
  74                posn += retval;
  75        } while (posn < size);
  76
  77        obj_req->stream.avail_in = size;
  78        obj_req->stream.next_in = ptr;
  79        do {
  80                obj_req->stream.next_out = expn;
  81                obj_req->stream.avail_out = sizeof(expn);
  82                obj_req->zret = inflate(&obj_req->stream, Z_SYNC_FLUSH);
  83                SHA1_Update(&obj_req->c, expn,
  84                            sizeof(expn) - obj_req->stream.avail_out);
  85        } while (obj_req->stream.avail_in && obj_req->zret == Z_OK);
  86        data_received++;
  87        return size;
  88}
  89
  90static void fetch_alternates(char *base);
  91
  92static void process_object_response(void *callback_data);
  93
  94static void start_object_request(struct object_request *obj_req)
  95{
  96        char *hex = sha1_to_hex(obj_req->sha1);
  97        char prevfile[PATH_MAX];
  98        char *url;
  99        char *posn;
 100        int prevlocal;
 101        unsigned char prev_buf[PREV_BUF_SIZE];
 102        ssize_t prev_read = 0;
 103        long prev_posn = 0;
 104        char range[RANGE_HEADER_SIZE];
 105        struct curl_slist *range_header = NULL;
 106        struct active_request_slot *slot;
 107
 108        snprintf(prevfile, sizeof(prevfile), "%s.prev", obj_req->filename);
 109        unlink(prevfile);
 110        rename(obj_req->tmpfile, prevfile);
 111        unlink(obj_req->tmpfile);
 112
 113        if (obj_req->local != -1)
 114                error("fd leakage in start: %d", obj_req->local);
 115        obj_req->local = open(obj_req->tmpfile,
 116                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 117        /* This could have failed due to the "lazy directory creation";
 118         * try to mkdir the last path component.
 119         */
 120        if (obj_req->local < 0 && errno == ENOENT) {
 121                char *dir = strrchr(obj_req->tmpfile, '/');
 122                if (dir) {
 123                        *dir = 0;
 124                        mkdir(obj_req->tmpfile, 0777);
 125                        *dir = '/';
 126                }
 127                obj_req->local = open(obj_req->tmpfile,
 128                                      O_WRONLY | O_CREAT | O_EXCL, 0666);
 129        }
 130
 131        if (obj_req->local < 0) {
 132                obj_req->state = ABORTED;
 133                error("Couldn't create temporary file %s for %s: %s",
 134                      obj_req->tmpfile, obj_req->filename, strerror(errno));
 135                return;
 136        }
 137
 138        memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 139
 140        inflateInit(&obj_req->stream);
 141
 142        SHA1_Init(&obj_req->c);
 143
 144        url = xmalloc(strlen(obj_req->repo->base) + 50);
 145        obj_req->url = xmalloc(strlen(obj_req->repo->base) + 50);
 146        strcpy(url, obj_req->repo->base);
 147        posn = url + strlen(obj_req->repo->base);
 148        strcpy(posn, "objects/");
 149        posn += 8;
 150        memcpy(posn, hex, 2);
 151        posn += 2;
 152        *(posn++) = '/';
 153        strcpy(posn, hex + 2);
 154        strcpy(obj_req->url, url);
 155
 156        /* If a previous temp file is present, process what was already
 157           fetched. */
 158        prevlocal = open(prevfile, O_RDONLY);
 159        if (prevlocal != -1) {
 160                do {
 161                        prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 162                        if (prev_read>0) {
 163                                if (fwrite_sha1_file(prev_buf,
 164                                                     1,
 165                                                     prev_read,
 166                                                     obj_req) == prev_read) {
 167                                        prev_posn += prev_read;
 168                                } else {
 169                                        prev_read = -1;
 170                                }
 171                        }
 172                } while (prev_read > 0);
 173                close(prevlocal);
 174        }
 175        unlink(prevfile);
 176
 177        /* Reset inflate/SHA1 if there was an error reading the previous temp
 178           file; also rewind to the beginning of the local file. */
 179        if (prev_read == -1) {
 180                memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 181                inflateInit(&obj_req->stream);
 182                SHA1_Init(&obj_req->c);
 183                if (prev_posn>0) {
 184                        prev_posn = 0;
 185                        lseek(obj_req->local, SEEK_SET, 0);
 186                        ftruncate(obj_req->local, 0);
 187                }
 188        }
 189
 190        slot = get_active_slot();
 191        slot->callback_func = process_object_response;
 192        slot->callback_data = obj_req;
 193        obj_req->slot = slot;
 194
 195        curl_easy_setopt(slot->curl, CURLOPT_FILE, obj_req);
 196        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 197        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, obj_req->errorstr);
 198        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 199        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 200
 201        /* If we have successfully processed data from a previous fetch
 202           attempt, only fetch the data we don't already have. */
 203        if (prev_posn>0) {
 204                if (get_verbosely)
 205                        fprintf(stderr,
 206                                "Resuming fetch of object %s at byte %ld\n",
 207                                hex, prev_posn);
 208                sprintf(range, "Range: bytes=%ld-", prev_posn);
 209                range_header = curl_slist_append(range_header, range);
 210                curl_easy_setopt(slot->curl,
 211                                 CURLOPT_HTTPHEADER, range_header);
 212        }
 213
 214        /* Try to get the request started, abort the request on error */
 215        obj_req->state = ACTIVE;
 216        if (!start_active_slot(slot)) {
 217                obj_req->state = ABORTED;
 218                obj_req->slot = NULL;
 219                close(obj_req->local); obj_req->local = -1;
 220                free(obj_req->url);
 221                return;
 222        }
 223}
 224
 225static void finish_object_request(struct object_request *obj_req)
 226{
 227        struct stat st;
 228
 229        fchmod(obj_req->local, 0444);
 230        close(obj_req->local); obj_req->local = -1;
 231
 232        if (obj_req->http_code == 416) {
 233                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 234        } else if (obj_req->curl_result != CURLE_OK) {
 235                if (stat(obj_req->tmpfile, &st) == 0)
 236                        if (st.st_size == 0)
 237                                unlink(obj_req->tmpfile);
 238                return;
 239        }
 240
 241        inflateEnd(&obj_req->stream);
 242        SHA1_Final(obj_req->real_sha1, &obj_req->c);
 243        if (obj_req->zret != Z_STREAM_END) {
 244                unlink(obj_req->tmpfile);
 245                return;
 246        }
 247        if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 248                unlink(obj_req->tmpfile);
 249                return;
 250        }
 251        obj_req->rename =
 252                move_temp_to_file(obj_req->tmpfile, obj_req->filename);
 253
 254        if (obj_req->rename == 0)
 255                pull_say("got %s\n", sha1_to_hex(obj_req->sha1));
 256}
 257
 258static void process_object_response(void *callback_data)
 259{
 260        struct object_request *obj_req =
 261                (struct object_request *)callback_data;
 262
 263        obj_req->curl_result = obj_req->slot->curl_result;
 264        obj_req->http_code = obj_req->slot->http_code;
 265        obj_req->slot = NULL;
 266        obj_req->state = COMPLETE;
 267
 268        /* Use alternates if necessary */
 269        if (obj_req->http_code == 404 ||
 270            obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 271                fetch_alternates(alt->base);
 272                if (obj_req->repo->next != NULL) {
 273                        obj_req->repo =
 274                                obj_req->repo->next;
 275                        close(obj_req->local);
 276                        obj_req->local = -1;
 277                        start_object_request(obj_req);
 278                        return;
 279                }
 280        }
 281
 282        finish_object_request(obj_req);
 283}
 284
 285static void release_object_request(struct object_request *obj_req)
 286{
 287        struct object_request *entry = object_queue_head;
 288
 289        if (obj_req->local != -1)
 290                error("fd leakage in release: %d", obj_req->local);
 291        if (obj_req == object_queue_head) {
 292                object_queue_head = obj_req->next;
 293        } else {
 294                while (entry->next != NULL && entry->next != obj_req)
 295                        entry = entry->next;
 296                if (entry->next == obj_req)
 297                        entry->next = entry->next->next;
 298        }
 299
 300        free(obj_req->url);
 301        free(obj_req);
 302}
 303
 304#ifdef USE_CURL_MULTI
 305void fill_active_slots(void)
 306{
 307        struct object_request *obj_req = object_queue_head;
 308        struct active_request_slot *slot = active_queue_head;
 309        int num_transfers;
 310
 311        while (active_requests < max_requests && obj_req != NULL) {
 312                if (obj_req->state == WAITING) {
 313                        if (has_sha1_file(obj_req->sha1))
 314                                obj_req->state = COMPLETE;
 315                        else
 316                                start_object_request(obj_req);
 317                        curl_multi_perform(curlm, &num_transfers);
 318                }
 319                obj_req = obj_req->next;
 320        }
 321
 322        while (slot != NULL) {
 323                if (!slot->in_use && slot->curl != NULL) {
 324                        curl_easy_cleanup(slot->curl);
 325                        slot->curl = NULL;
 326                }
 327                slot = slot->next;
 328        }
 329}
 330#endif
 331
 332void prefetch(unsigned char *sha1)
 333{
 334        struct object_request *newreq;
 335        struct object_request *tail;
 336        char *filename = sha1_file_name(sha1);
 337
 338        newreq = xmalloc(sizeof(*newreq));
 339        memcpy(newreq->sha1, sha1, 20);
 340        newreq->repo = alt;
 341        newreq->url = NULL;
 342        newreq->local = -1;
 343        newreq->state = WAITING;
 344        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 345        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 346                 "%s.temp", filename);
 347        newreq->next = NULL;
 348
 349        if (object_queue_head == NULL) {
 350                object_queue_head = newreq;
 351        } else {
 352                tail = object_queue_head;
 353                while (tail->next != NULL) {
 354                        tail = tail->next;
 355                }
 356                tail->next = newreq;
 357        }
 358
 359#ifdef USE_CURL_MULTI
 360        fill_active_slots();
 361        step_active_slots();
 362#endif
 363}
 364
 365static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 366{
 367        char *hex = sha1_to_hex(sha1);
 368        char *filename;
 369        char *url;
 370        char tmpfile[PATH_MAX];
 371        long prev_posn = 0;
 372        char range[RANGE_HEADER_SIZE];
 373        struct curl_slist *range_header = NULL;
 374
 375        FILE *indexfile;
 376        struct active_request_slot *slot;
 377        struct slot_results results;
 378
 379        if (has_pack_index(sha1))
 380                return 0;
 381
 382        if (get_verbosely)
 383                fprintf(stderr, "Getting index for pack %s\n", hex);
 384
 385        url = xmalloc(strlen(repo->base) + 64);
 386        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 387
 388        filename = sha1_pack_index_name(sha1);
 389        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 390        indexfile = fopen(tmpfile, "a");
 391        if (!indexfile)
 392                return error("Unable to open local file %s for pack index",
 393                             filename);
 394
 395        slot = get_active_slot();
 396        slot->results = &results;
 397        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 398        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 399        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 400        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 401        slot->local = indexfile;
 402
 403        /* If there is data present from a previous transfer attempt,
 404           resume where it left off */
 405        prev_posn = ftell(indexfile);
 406        if (prev_posn>0) {
 407                if (get_verbosely)
 408                        fprintf(stderr,
 409                                "Resuming fetch of index for pack %s at byte %ld\n",
 410                                hex, prev_posn);
 411                sprintf(range, "Range: bytes=%ld-", prev_posn);
 412                range_header = curl_slist_append(range_header, range);
 413                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 414        }
 415
 416        if (start_active_slot(slot)) {
 417                run_active_slot(slot);
 418                if (results.curl_result != CURLE_OK) {
 419                        fclose(indexfile);
 420                        return error("Unable to get pack index %s\n%s", url,
 421                                     curl_errorstr);
 422                }
 423        } else {
 424                fclose(indexfile);
 425                return error("Unable to start request");
 426        }
 427
 428        fclose(indexfile);
 429
 430        return move_temp_to_file(tmpfile, filename);
 431}
 432
 433static int setup_index(struct alt_base *repo, unsigned char *sha1)
 434{
 435        struct packed_git *new_pack;
 436        if (has_pack_file(sha1))
 437                return 0; // don't list this as something we can get
 438
 439        if (fetch_index(repo, sha1))
 440                return -1;
 441
 442        new_pack = parse_pack_index(sha1);
 443        new_pack->next = repo->packs;
 444        repo->packs = new_pack;
 445        return 0;
 446}
 447
 448static void process_alternates_response(void *callback_data)
 449{
 450        struct alternates_request *alt_req =
 451                (struct alternates_request *)callback_data;
 452        struct active_request_slot *slot = alt_req->slot;
 453        struct alt_base *tail = alt;
 454        char *base = alt_req->base;
 455        static const char null_byte = '\0';
 456        char *data;
 457        int i = 0;
 458
 459        if (alt_req->http_specific) {
 460                if (slot->curl_result != CURLE_OK ||
 461                    !alt_req->buffer->posn) {
 462
 463                        /* Try reusing the slot to get non-http alternates */
 464                        alt_req->http_specific = 0;
 465                        sprintf(alt_req->url, "%s/objects/info/alternates",
 466                                base);
 467                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 468                                         alt_req->url);
 469                        active_requests++;
 470                        slot->in_use = 1;
 471                        if (slot->finished != NULL)
 472                                (*slot->finished) = 0;
 473                        if (!start_active_slot(slot)) {
 474                                got_alternates = -1;
 475                                slot->in_use = 0;
 476                                if (slot->finished != NULL)
 477                                        (*slot->finished) = 1;
 478                        }
 479                        return;
 480                }
 481        } else if (slot->curl_result != CURLE_OK) {
 482                if (slot->http_code != 404 &&
 483                    slot->curl_result != CURLE_FILE_COULDNT_READ_FILE) {
 484                        got_alternates = -1;
 485                        return;
 486                }
 487        }
 488
 489        fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 490        alt_req->buffer->posn--;
 491        data = alt_req->buffer->buffer;
 492
 493        while (i < alt_req->buffer->posn) {
 494                int posn = i;
 495                while (posn < alt_req->buffer->posn && data[posn] != '\n')
 496                        posn++;
 497                if (data[posn] == '\n') {
 498                        int okay = 0;
 499                        int serverlen = 0;
 500                        struct alt_base *newalt;
 501                        char *target = NULL;
 502                        if (data[i] == '/') {
 503                                serverlen = strchr(base + 8, '/') - base;
 504                                okay = 1;
 505                        } else if (!memcmp(data + i, "../", 3)) {
 506                                i += 3;
 507                                serverlen = strlen(base);
 508                                while (i + 2 < posn &&
 509                                       !memcmp(data + i, "../", 3)) {
 510                                        do {
 511                                                serverlen--;
 512                                        } while (serverlen &&
 513                                                 base[serverlen - 1] != '/');
 514                                        i += 3;
 515                                }
 516                                // If the server got removed, give up.
 517                                okay = strchr(base, ':') - base + 3 <
 518                                        serverlen;
 519                        } else if (alt_req->http_specific) {
 520                                char *colon = strchr(data + i, ':');
 521                                char *slash = strchr(data + i, '/');
 522                                if (colon && slash && colon < data + posn &&
 523                                    slash < data + posn && colon < slash) {
 524                                        okay = 1;
 525                                }
 526                        }
 527                        // skip 'objects' at end
 528                        if (okay) {
 529                                target = xmalloc(serverlen + posn - i - 6);
 530                                strncpy(target, base, serverlen);
 531                                strncpy(target + serverlen, data + i,
 532                                        posn - i - 7);
 533                                target[serverlen + posn - i - 7] = '\0';
 534                                if (get_verbosely)
 535                                        fprintf(stderr,
 536                                                "Also look at %s\n", target);
 537                                newalt = xmalloc(sizeof(*newalt));
 538                                newalt->next = NULL;
 539                                newalt->base = target;
 540                                newalt->got_indices = 0;
 541                                newalt->packs = NULL;
 542                                while (tail->next != NULL)
 543                                        tail = tail->next;
 544                                tail->next = newalt;
 545                        }
 546                }
 547                i = posn + 1;
 548        }
 549
 550        got_alternates = 1;
 551}
 552
 553static void fetch_alternates(char *base)
 554{
 555        struct buffer buffer;
 556        char *url;
 557        char *data;
 558        struct active_request_slot *slot;
 559        struct alternates_request alt_req;
 560
 561        /* If another request has already started fetching alternates,
 562           wait for them to arrive and return to processing this request's
 563           curl message */
 564#ifdef USE_CURL_MULTI
 565        while (got_alternates == 0) {
 566                step_active_slots();
 567        }
 568#endif
 569
 570        /* Nothing to do if they've already been fetched */
 571        if (got_alternates == 1)
 572                return;
 573
 574        /* Start the fetch */
 575        got_alternates = 0;
 576
 577        data = xmalloc(4096);
 578        buffer.size = 4096;
 579        buffer.posn = 0;
 580        buffer.buffer = data;
 581
 582        if (get_verbosely)
 583                fprintf(stderr, "Getting alternates list for %s\n", base);
 584
 585        url = xmalloc(strlen(base) + 31);
 586        sprintf(url, "%s/objects/info/http-alternates", base);
 587
 588        /* Use a callback to process the result, since another request
 589           may fail and need to have alternates loaded before continuing */
 590        slot = get_active_slot();
 591        slot->callback_func = process_alternates_response;
 592        slot->callback_data = &alt_req;
 593
 594        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 595        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 596        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 597
 598        alt_req.base = base;
 599        alt_req.url = url;
 600        alt_req.buffer = &buffer;
 601        alt_req.http_specific = 1;
 602        alt_req.slot = slot;
 603
 604        if (start_active_slot(slot))
 605                run_active_slot(slot);
 606        else
 607                got_alternates = -1;
 608
 609        free(data);
 610        free(url);
 611}
 612
 613static int fetch_indices(struct alt_base *repo)
 614{
 615        unsigned char sha1[20];
 616        char *url;
 617        struct buffer buffer;
 618        char *data;
 619        int i = 0;
 620
 621        struct active_request_slot *slot;
 622        struct slot_results results;
 623
 624        if (repo->got_indices)
 625                return 0;
 626
 627        data = xmalloc(4096);
 628        buffer.size = 4096;
 629        buffer.posn = 0;
 630        buffer.buffer = data;
 631
 632        if (get_verbosely)
 633                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 634
 635        url = xmalloc(strlen(repo->base) + 21);
 636        sprintf(url, "%s/objects/info/packs", repo->base);
 637
 638        slot = get_active_slot();
 639        slot->results = &results;
 640        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 641        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 642        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 643        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 644        if (start_active_slot(slot)) {
 645                run_active_slot(slot);
 646                if (results.curl_result != CURLE_OK) {
 647                        if (results.http_code == 404 ||
 648                            results.curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 649                                repo->got_indices = 1;
 650                                free(buffer.buffer);
 651                                return 0;
 652                        } else {
 653                                repo->got_indices = 0;
 654                                free(buffer.buffer);
 655                                return error("%s", curl_errorstr);
 656                        }
 657                }
 658        } else {
 659                repo->got_indices = 0;
 660                free(buffer.buffer);
 661                return error("Unable to start request");
 662        }
 663
 664        data = buffer.buffer;
 665        while (i < buffer.posn) {
 666                switch (data[i]) {
 667                case 'P':
 668                        i++;
 669                        if (i + 52 <= buffer.posn &&
 670                            !strncmp(data + i, " pack-", 6) &&
 671                            !strncmp(data + i + 46, ".pack\n", 6)) {
 672                                get_sha1_hex(data + i + 6, sha1);
 673                                setup_index(repo, sha1);
 674                                i += 51;
 675                                break;
 676                        }
 677                default:
 678                        while (i < buffer.posn && data[i] != '\n')
 679                                i++;
 680                }
 681                i++;
 682        }
 683
 684        free(buffer.buffer);
 685        repo->got_indices = 1;
 686        return 0;
 687}
 688
 689static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 690{
 691        char *url;
 692        struct packed_git *target;
 693        struct packed_git **lst;
 694        FILE *packfile;
 695        char *filename;
 696        char tmpfile[PATH_MAX];
 697        int ret;
 698        long prev_posn = 0;
 699        char range[RANGE_HEADER_SIZE];
 700        struct curl_slist *range_header = NULL;
 701
 702        struct active_request_slot *slot;
 703        struct slot_results results;
 704
 705        if (fetch_indices(repo))
 706                return -1;
 707        target = find_sha1_pack(sha1, repo->packs);
 708        if (!target)
 709                return -1;
 710
 711        if (get_verbosely) {
 712                fprintf(stderr, "Getting pack %s\n",
 713                        sha1_to_hex(target->sha1));
 714                fprintf(stderr, " which contains %s\n",
 715                        sha1_to_hex(sha1));
 716        }
 717
 718        url = xmalloc(strlen(repo->base) + 65);
 719        sprintf(url, "%s/objects/pack/pack-%s.pack",
 720                repo->base, sha1_to_hex(target->sha1));
 721
 722        filename = sha1_pack_name(target->sha1);
 723        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 724        packfile = fopen(tmpfile, "a");
 725        if (!packfile)
 726                return error("Unable to open local file %s for pack",
 727                             filename);
 728
 729        slot = get_active_slot();
 730        slot->results = &results;
 731        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 732        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 733        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 734        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 735        slot->local = packfile;
 736
 737        /* If there is data present from a previous transfer attempt,
 738           resume where it left off */
 739        prev_posn = ftell(packfile);
 740        if (prev_posn>0) {
 741                if (get_verbosely)
 742                        fprintf(stderr,
 743                                "Resuming fetch of pack %s at byte %ld\n",
 744                                sha1_to_hex(target->sha1), prev_posn);
 745                sprintf(range, "Range: bytes=%ld-", prev_posn);
 746                range_header = curl_slist_append(range_header, range);
 747                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 748        }
 749
 750        if (start_active_slot(slot)) {
 751                run_active_slot(slot);
 752                if (results.curl_result != CURLE_OK) {
 753                        fclose(packfile);
 754                        return error("Unable to get pack file %s\n%s", url,
 755                                     curl_errorstr);
 756                }
 757        } else {
 758                fclose(packfile);
 759                return error("Unable to start request");
 760        }
 761
 762        fclose(packfile);
 763
 764        ret = move_temp_to_file(tmpfile, filename);
 765        if (ret)
 766                return ret;
 767
 768        lst = &repo->packs;
 769        while (*lst != target)
 770                lst = &((*lst)->next);
 771        *lst = (*lst)->next;
 772
 773        if (verify_pack(target, 0))
 774                return -1;
 775        install_packed_git(target);
 776
 777        return 0;
 778}
 779
 780static void abort_object_request(struct object_request *obj_req)
 781{
 782        if (obj_req->local >= 0) {
 783                close(obj_req->local);
 784                obj_req->local = -1;
 785        }
 786        unlink(obj_req->tmpfile);
 787        if (obj_req->slot) {
 788                release_active_slot(obj_req->slot);
 789                obj_req->slot = NULL;
 790        }
 791        release_object_request(obj_req);
 792}
 793
 794static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 795{
 796        char *hex = sha1_to_hex(sha1);
 797        int ret = 0;
 798        struct object_request *obj_req = object_queue_head;
 799
 800        while (obj_req != NULL && memcmp(obj_req->sha1, sha1, 20))
 801                obj_req = obj_req->next;
 802        if (obj_req == NULL)
 803                return error("Couldn't find request for %s in the queue", hex);
 804
 805        if (has_sha1_file(obj_req->sha1)) {
 806                abort_object_request(obj_req);
 807                return 0;
 808        }
 809
 810#ifdef USE_CURL_MULTI
 811        while (obj_req->state == WAITING) {
 812                step_active_slots();
 813        }
 814#else
 815        start_object_request(obj_req);
 816#endif
 817
 818        while (obj_req->state == ACTIVE) {
 819                run_active_slot(obj_req->slot);
 820        }
 821        if (obj_req->local != -1) {
 822                close(obj_req->local); obj_req->local = -1;
 823        }
 824
 825        if (obj_req->state == ABORTED) {
 826                ret = error("Request for %s aborted", hex);
 827        } else if (obj_req->curl_result != CURLE_OK &&
 828                   obj_req->http_code != 416) {
 829                if (obj_req->http_code == 404 ||
 830                    obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE)
 831                        ret = -1; /* Be silent, it is probably in a pack. */
 832                else
 833                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 834                                    obj_req->errorstr, obj_req->curl_result,
 835                                    obj_req->http_code, hex);
 836        } else if (obj_req->zret != Z_STREAM_END) {
 837                ret = error("File %s (%s) corrupt", hex, obj_req->url);
 838        } else if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 839                ret = error("File %s has bad hash", hex);
 840        } else if (obj_req->rename < 0) {
 841                ret = error("unable to write sha1 filename %s",
 842                            obj_req->filename);
 843        }
 844
 845        release_object_request(obj_req);
 846        return ret;
 847}
 848
 849int fetch(unsigned char *sha1)
 850{
 851        struct alt_base *altbase = alt;
 852
 853        if (!fetch_object(altbase, sha1))
 854                return 0;
 855        while (altbase) {
 856                if (!fetch_pack(altbase, sha1))
 857                        return 0;
 858                fetch_alternates(alt->base);
 859                altbase = altbase->next;
 860        }
 861        return error("Unable to find %s under %s", sha1_to_hex(sha1),
 862                     alt->base);
 863}
 864
 865static inline int needs_quote(int ch)
 866{
 867        switch (ch) {
 868        case '/': case '-': case '.':
 869        case 'A'...'Z': case 'a'...'z': case '0'...'9':
 870                return 0;
 871        default:
 872                return 1;
 873        }
 874}
 875
 876static inline int hex(int v)
 877{
 878        if (v < 10) return '0' + v;
 879        else return 'A' + v - 10;
 880}
 881
 882static char *quote_ref_url(const char *base, const char *ref)
 883{
 884        const char *cp;
 885        char *dp, *qref;
 886        int len, baselen, ch;
 887
 888        baselen = strlen(base);
 889        len = baselen + 6; /* "refs/" + NUL */
 890        for (cp = ref; (ch = *cp) != 0; cp++, len++)
 891                if (needs_quote(ch))
 892                        len += 2; /* extra two hex plus replacement % */
 893        qref = xmalloc(len);
 894        memcpy(qref, base, baselen);
 895        memcpy(qref + baselen, "refs/", 5);
 896        for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
 897                if (needs_quote(ch)) {
 898                        *dp++ = '%';
 899                        *dp++ = hex((ch >> 4) & 0xF);
 900                        *dp++ = hex(ch & 0xF);
 901                }
 902                else
 903                        *dp++ = ch;
 904        }
 905        *dp = 0;
 906
 907        return qref;
 908}
 909
 910int fetch_ref(char *ref, unsigned char *sha1)
 911{
 912        char *url;
 913        char hex[42];
 914        struct buffer buffer;
 915        char *base = alt->base;
 916        struct active_request_slot *slot;
 917        struct slot_results results;
 918        buffer.size = 41;
 919        buffer.posn = 0;
 920        buffer.buffer = hex;
 921        hex[41] = '\0';
 922
 923        url = quote_ref_url(base, ref);
 924        slot = get_active_slot();
 925        slot->results = &results;
 926        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 927        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 928        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 929        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 930        if (start_active_slot(slot)) {
 931                run_active_slot(slot);
 932                if (results.curl_result != CURLE_OK)
 933                        return error("Couldn't get %s for %s\n%s",
 934                                     url, ref, curl_errorstr);
 935        } else {
 936                return error("Unable to start request");
 937        }
 938
 939        hex[40] = '\0';
 940        get_sha1_hex(hex, sha1);
 941        return 0;
 942}
 943
 944int main(int argc, char **argv)
 945{
 946        char *commit_id;
 947        char *url;
 948        int arg = 1;
 949        int rc = 0;
 950
 951        setup_git_directory();
 952
 953        while (arg < argc && argv[arg][0] == '-') {
 954                if (argv[arg][1] == 't') {
 955                        get_tree = 1;
 956                } else if (argv[arg][1] == 'c') {
 957                        get_history = 1;
 958                } else if (argv[arg][1] == 'a') {
 959                        get_all = 1;
 960                        get_tree = 1;
 961                        get_history = 1;
 962                } else if (argv[arg][1] == 'v') {
 963                        get_verbosely = 1;
 964                } else if (argv[arg][1] == 'w') {
 965                        write_ref = argv[arg + 1];
 966                        arg++;
 967                } else if (!strcmp(argv[arg], "--recover")) {
 968                        get_recover = 1;
 969                }
 970                arg++;
 971        }
 972        if (argc < arg + 2) {
 973                usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
 974                return 1;
 975        }
 976        commit_id = argv[arg];
 977        url = argv[arg + 1];
 978
 979        http_init();
 980
 981        no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 982
 983        alt = xmalloc(sizeof(*alt));
 984        alt->base = url;
 985        alt->got_indices = 0;
 986        alt->packs = NULL;
 987        alt->next = NULL;
 988
 989        if (pull(commit_id))
 990                rc = 1;
 991
 992        curl_slist_free_all(no_pragma_header);
 993
 994        http_cleanup();
 995
 996        return rc;
 997}