Andrew's git - gitweb.git/blob

bbc3023e40021877a9fd1bba9e36d97ca6e06a23
   1#include "cache.h"
   2#include "commit.h"
   3#include "pack.h"
   4#include "walker.h"
   5#include "http.h"
   6
   7#define PREV_BUF_SIZE 4096
   8#define RANGE_HEADER_SIZE 30
   9
  10struct alt_base
  11{
  12        char *base;
  13        int got_indices;
  14        struct packed_git *packs;
  15        struct alt_base *next;
  16};
  17
  18enum object_request_state {
  19        WAITING,
  20        ABORTED,
  21        ACTIVE,
  22        COMPLETE,
  23};
  24
  25struct object_request
  26{
  27        struct walker *walker;
  28        unsigned char sha1[20];
  29        struct alt_base *repo;
  30        char *url;
  31        char filename[PATH_MAX];
  32        char tmpfile[PATH_MAX];
  33        int local;
  34        enum object_request_state state;
  35        CURLcode curl_result;
  36        char errorstr[CURL_ERROR_SIZE];
  37        long http_code;
  38        unsigned char real_sha1[20];
  39        git_SHA_CTX c;
  40        z_stream stream;
  41        int zret;
  42        int rename;
  43        struct active_request_slot *slot;
  44        struct object_request *next;
  45};
  46
  47struct alternates_request {
  48        struct walker *walker;
  49        const char *base;
  50        char *url;
  51        struct strbuf *buffer;
  52        struct active_request_slot *slot;
  53        int http_specific;
  54};
  55
  56struct walker_data {
  57        const char *url;
  58        int got_alternates;
  59        struct alt_base *alt;
  60        struct curl_slist *no_pragma_header;
  61};
  62
  63static struct object_request *object_queue_head;
  64
  65static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
  66                               void *data)
  67{
  68        unsigned char expn[4096];
  69        size_t size = eltsize * nmemb;
  70        int posn = 0;
  71        struct object_request *obj_req = (struct object_request *)data;
  72        do {
  73                ssize_t retval = xwrite(obj_req->local,
  74                                        (char *) ptr + posn, size - posn);
  75                if (retval < 0)
  76                        return posn;
  77                posn += retval;
  78        } while (posn < size);
  79
  80        obj_req->stream.avail_in = size;
  81        obj_req->stream.next_in = ptr;
  82        do {
  83                obj_req->stream.next_out = expn;
  84                obj_req->stream.avail_out = sizeof(expn);
  85                obj_req->zret = git_inflate(&obj_req->stream, Z_SYNC_FLUSH);
  86                git_SHA1_Update(&obj_req->c, expn,
  87                                sizeof(expn) - obj_req->stream.avail_out);
  88        } while (obj_req->stream.avail_in && obj_req->zret == Z_OK);
  89        data_received++;
  90        return size;
  91}
  92
  93static void fetch_alternates(struct walker *walker, const char *base);
  94
  95static void process_object_response(void *callback_data);
  96
  97static void start_object_request(struct walker *walker,
  98                                 struct object_request *obj_req)
  99{
 100        char *hex = sha1_to_hex(obj_req->sha1);
 101        char prevfile[PATH_MAX];
 102        char *url;
 103        char *posn;
 104        int prevlocal;
 105        unsigned char prev_buf[PREV_BUF_SIZE];
 106        ssize_t prev_read = 0;
 107        long prev_posn = 0;
 108        char range[RANGE_HEADER_SIZE];
 109        struct curl_slist *range_header = NULL;
 110        struct active_request_slot *slot;
 111        struct walker_data *data = walker->data;
 112
 113        snprintf(prevfile, sizeof(prevfile), "%s.prev", obj_req->filename);
 114        unlink_or_warn(prevfile);
 115        rename(obj_req->tmpfile, prevfile);
 116        unlink_or_warn(obj_req->tmpfile);
 117
 118        if (obj_req->local != -1)
 119                error("fd leakage in start: %d", obj_req->local);
 120        obj_req->local = open(obj_req->tmpfile,
 121                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 122        /*
 123         * This could have failed due to the "lazy directory creation";
 124         * try to mkdir the last path component.
 125         */
 126        if (obj_req->local < 0 && errno == ENOENT) {
 127                char *dir = strrchr(obj_req->tmpfile, '/');
 128                if (dir) {
 129                        *dir = 0;
 130                        mkdir(obj_req->tmpfile, 0777);
 131                        *dir = '/';
 132                }
 133                obj_req->local = open(obj_req->tmpfile,
 134                                      O_WRONLY | O_CREAT | O_EXCL, 0666);
 135        }
 136
 137        if (obj_req->local < 0) {
 138                obj_req->state = ABORTED;
 139                error("Couldn't create temporary file %s for %s: %s",
 140                      obj_req->tmpfile, obj_req->filename, strerror(errno));
 141                return;
 142        }
 143
 144        memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 145
 146        git_inflate_init(&obj_req->stream);
 147
 148        git_SHA1_Init(&obj_req->c);
 149
 150        url = xmalloc(strlen(obj_req->repo->base) + 51);
 151        obj_req->url = xmalloc(strlen(obj_req->repo->base) + 51);
 152        strcpy(url, obj_req->repo->base);
 153        posn = url + strlen(obj_req->repo->base);
 154        strcpy(posn, "/objects/");
 155        posn += 9;
 156        memcpy(posn, hex, 2);
 157        posn += 2;
 158        *(posn++) = '/';
 159        strcpy(posn, hex + 2);
 160        strcpy(obj_req->url, url);
 161
 162        /*
 163         * If a previous temp file is present, process what was already
 164         * fetched.
 165         */
 166        prevlocal = open(prevfile, O_RDONLY);
 167        if (prevlocal != -1) {
 168                do {
 169                        prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
 170                        if (prev_read>0) {
 171                                if (fwrite_sha1_file(prev_buf,
 172                                                     1,
 173                                                     prev_read,
 174                                                     obj_req) == prev_read)
 175                                        prev_posn += prev_read;
 176                                else
 177                                        prev_read = -1;
 178                        }
 179                } while (prev_read > 0);
 180                close(prevlocal);
 181        }
 182        unlink_or_warn(prevfile);
 183
 184        /*
 185         * Reset inflate/SHA1 if there was an error reading the previous temp
 186         * file; also rewind to the beginning of the local file.
 187         */
 188        if (prev_read == -1) {
 189                memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 190                git_inflate_init(&obj_req->stream);
 191                git_SHA1_Init(&obj_req->c);
 192                if (prev_posn>0) {
 193                        prev_posn = 0;
 194                        lseek(obj_req->local, 0, SEEK_SET);
 195                        ftruncate(obj_req->local, 0);
 196                }
 197        }
 198
 199        slot = get_active_slot();
 200        slot->callback_func = process_object_response;
 201        slot->callback_data = obj_req;
 202        obj_req->slot = slot;
 203
 204        curl_easy_setopt(slot->curl, CURLOPT_FILE, obj_req);
 205        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 206        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, obj_req->errorstr);
 207        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 208        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 209
 210        /*
 211         * If we have successfully processed data from a previous fetch
 212         * attempt, only fetch the data we don't already have.
 213         */
 214        if (prev_posn>0) {
 215                if (walker->get_verbosely)
 216                        fprintf(stderr,
 217                                "Resuming fetch of object %s at byte %ld\n",
 218                                hex, prev_posn);
 219                sprintf(range, "Range: bytes=%ld-", prev_posn);
 220                range_header = curl_slist_append(range_header, range);
 221                curl_easy_setopt(slot->curl,
 222                                 CURLOPT_HTTPHEADER, range_header);
 223        }
 224
 225        /* Try to get the request started, abort the request on error */
 226        obj_req->state = ACTIVE;
 227        if (!start_active_slot(slot)) {
 228                obj_req->state = ABORTED;
 229                obj_req->slot = NULL;
 230                close(obj_req->local);
 231                obj_req->local = -1;
 232                free(obj_req->url);
 233                return;
 234        }
 235}
 236
 237static void finish_object_request(struct object_request *obj_req)
 238{
 239        struct stat st;
 240
 241        close(obj_req->local);
 242        obj_req->local = -1;
 243
 244        if (obj_req->http_code == 416) {
 245                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 246        } else if (obj_req->curl_result != CURLE_OK) {
 247                if (stat(obj_req->tmpfile, &st) == 0)
 248                        if (st.st_size == 0)
 249                                unlink_or_warn(obj_req->tmpfile);
 250                return;
 251        }
 252
 253        git_inflate_end(&obj_req->stream);
 254        git_SHA1_Final(obj_req->real_sha1, &obj_req->c);
 255        if (obj_req->zret != Z_STREAM_END) {
 256                unlink_or_warn(obj_req->tmpfile);
 257                return;
 258        }
 259        if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
 260                unlink_or_warn(obj_req->tmpfile);
 261                return;
 262        }
 263        obj_req->rename =
 264                move_temp_to_file(obj_req->tmpfile, obj_req->filename);
 265
 266        if (obj_req->rename == 0)
 267                walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
 268}
 269
 270static void process_object_response(void *callback_data)
 271{
 272        struct object_request *obj_req =
 273                (struct object_request *)callback_data;
 274        struct walker *walker = obj_req->walker;
 275        struct walker_data *data = walker->data;
 276        struct alt_base *alt = data->alt;
 277
 278        obj_req->curl_result = obj_req->slot->curl_result;
 279        obj_req->http_code = obj_req->slot->http_code;
 280        obj_req->slot = NULL;
 281        obj_req->state = COMPLETE;
 282
 283        /* Use alternates if necessary */
 284        if (missing_target(obj_req)) {
 285                fetch_alternates(walker, alt->base);
 286                if (obj_req->repo->next != NULL) {
 287                        obj_req->repo =
 288                                obj_req->repo->next;
 289                        close(obj_req->local);
 290                        obj_req->local = -1;
 291                        start_object_request(walker, obj_req);
 292                        return;
 293                }
 294        }
 295
 296        finish_object_request(obj_req);
 297}
 298
 299static void release_object_request(struct object_request *obj_req)
 300{
 301        struct object_request *entry = object_queue_head;
 302
 303        if (obj_req->local != -1)
 304                error("fd leakage in release: %d", obj_req->local);
 305        if (obj_req == object_queue_head) {
 306                object_queue_head = obj_req->next;
 307        } else {
 308                while (entry->next != NULL && entry->next != obj_req)
 309                        entry = entry->next;
 310                if (entry->next == obj_req)
 311                        entry->next = entry->next->next;
 312        }
 313
 314        free(obj_req->url);
 315        free(obj_req);
 316}
 317
 318#ifdef USE_CURL_MULTI
 319static int fill_active_slot(struct walker *walker)
 320{
 321        struct object_request *obj_req;
 322
 323        for (obj_req = object_queue_head; obj_req; obj_req = obj_req->next) {
 324                if (obj_req->state == WAITING) {
 325                        if (has_sha1_file(obj_req->sha1))
 326                                obj_req->state = COMPLETE;
 327                        else {
 328                                start_object_request(walker, obj_req);
 329                                return 1;
 330                        }
 331                }
 332        }
 333        return 0;
 334}
 335#endif
 336
 337static void prefetch(struct walker *walker, unsigned char *sha1)
 338{
 339        struct object_request *newreq;
 340        struct object_request *tail;
 341        struct walker_data *data = walker->data;
 342        char *filename = sha1_file_name(sha1);
 343
 344        newreq = xmalloc(sizeof(*newreq));
 345        newreq->walker = walker;
 346        hashcpy(newreq->sha1, sha1);
 347        newreq->repo = data->alt;
 348        newreq->url = NULL;
 349        newreq->local = -1;
 350        newreq->state = WAITING;
 351        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 352        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 353                 "%s.temp", filename);
 354        newreq->slot = NULL;
 355        newreq->next = NULL;
 356
 357        if (object_queue_head == NULL) {
 358                object_queue_head = newreq;
 359        } else {
 360                tail = object_queue_head;
 361                while (tail->next != NULL)
 362                        tail = tail->next;
 363                tail->next = newreq;
 364        }
 365
 366#ifdef USE_CURL_MULTI
 367        fill_active_slots();
 368        step_active_slots();
 369#endif
 370}
 371
 372static int fetch_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 373{
 374        char *hex = sha1_to_hex(sha1);
 375        char *filename;
 376        char *url;
 377        char tmpfile[PATH_MAX];
 378        long prev_posn = 0;
 379        char range[RANGE_HEADER_SIZE];
 380        struct curl_slist *range_header = NULL;
 381        struct walker_data *data = walker->data;
 382
 383        FILE *indexfile;
 384        struct active_request_slot *slot;
 385        struct slot_results results;
 386
 387        /* Don't use the index if the pack isn't there */
 388        url = xmalloc(strlen(repo->base) + 64);
 389        sprintf(url, "%s/objects/pack/pack-%s.pack", repo->base, hex);
 390        slot = get_active_slot();
 391        slot->results = &results;
 392        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 393        curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
 394        if (start_active_slot(slot)) {
 395                run_active_slot(slot);
 396                if (results.curl_result != CURLE_OK) {
 397                        free(url);
 398                        return error("Unable to verify pack %s is available",
 399                                     hex);
 400                }
 401        } else {
 402                free(url);
 403                return error("Unable to start request");
 404        }
 405
 406        if (has_pack_index(sha1)) {
 407                free(url);
 408                return 0;
 409        }
 410
 411        if (walker->get_verbosely)
 412                fprintf(stderr, "Getting index for pack %s\n", hex);
 413
 414        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 415
 416        filename = sha1_pack_index_name(sha1);
 417        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 418        indexfile = fopen(tmpfile, "a");
 419        if (!indexfile) {
 420                free(url);
 421                return error("Unable to open local file %s for pack index",
 422                             tmpfile);
 423        }
 424
 425        slot = get_active_slot();
 426        slot->results = &results;
 427        curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
 428        curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 429        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 430        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 431        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 432        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 433        slot->local = indexfile;
 434
 435        /*
 436         * If there is data present from a previous transfer attempt,
 437         * resume where it left off
 438         */
 439        prev_posn = ftell(indexfile);
 440        if (prev_posn>0) {
 441                if (walker->get_verbosely)
 442                        fprintf(stderr,
 443                                "Resuming fetch of index for pack %s at byte %ld\n",
 444                                hex, prev_posn);
 445                sprintf(range, "Range: bytes=%ld-", prev_posn);
 446                range_header = curl_slist_append(range_header, range);
 447                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 448        }
 449
 450        if (start_active_slot(slot)) {
 451                run_active_slot(slot);
 452                if (results.curl_result != CURLE_OK) {
 453                        free(url);
 454                        fclose(indexfile);
 455                        slot->local = NULL;
 456                        return error("Unable to get pack index %s\n%s", url,
 457                                     curl_errorstr);
 458                }
 459        } else {
 460                free(url);
 461                fclose(indexfile);
 462                slot->local = NULL;
 463                return error("Unable to start request");
 464        }
 465
 466        free(url);
 467        fclose(indexfile);
 468        slot->local = NULL;
 469
 470        return move_temp_to_file(tmpfile, filename);
 471}
 472
 473static int setup_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 474{
 475        struct packed_git *new_pack;
 476        if (has_pack_file(sha1))
 477                return 0; /* don't list this as something we can get */
 478
 479        if (fetch_index(walker, repo, sha1))
 480                return -1;
 481
 482        new_pack = parse_pack_index(sha1);
 483        if (!new_pack)
 484                return -1; /* parse_pack_index() already issued error message */
 485        new_pack->next = repo->packs;
 486        repo->packs = new_pack;
 487        return 0;
 488}
 489
 490static void process_alternates_response(void *callback_data)
 491{
 492        struct alternates_request *alt_req =
 493                (struct alternates_request *)callback_data;
 494        struct walker *walker = alt_req->walker;
 495        struct walker_data *cdata = walker->data;
 496        struct active_request_slot *slot = alt_req->slot;
 497        struct alt_base *tail = cdata->alt;
 498        const char *base = alt_req->base;
 499        static const char null_byte = '\0';
 500        char *data;
 501        int i = 0;
 502
 503        if (alt_req->http_specific) {
 504                if (slot->curl_result != CURLE_OK ||
 505                    !alt_req->buffer->len) {
 506
 507                        /* Try reusing the slot to get non-http alternates */
 508                        alt_req->http_specific = 0;
 509                        sprintf(alt_req->url, "%s/objects/info/alternates",
 510                                base);
 511                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 512                                         alt_req->url);
 513                        active_requests++;
 514                        slot->in_use = 1;
 515                        if (slot->finished != NULL)
 516                                (*slot->finished) = 0;
 517                        if (!start_active_slot(slot)) {
 518                                cdata->got_alternates = -1;
 519                                slot->in_use = 0;
 520                                if (slot->finished != NULL)
 521                                        (*slot->finished) = 1;
 522                        }
 523                        return;
 524                }
 525        } else if (slot->curl_result != CURLE_OK) {
 526                if (!missing_target(slot)) {
 527                        cdata->got_alternates = -1;
 528                        return;
 529                }
 530        }
 531
 532        fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 533        alt_req->buffer->len--;
 534        data = alt_req->buffer->buf;
 535
 536        while (i < alt_req->buffer->len) {
 537                int posn = i;
 538                while (posn < alt_req->buffer->len && data[posn] != '\n')
 539                        posn++;
 540                if (data[posn] == '\n') {
 541                        int okay = 0;
 542                        int serverlen = 0;
 543                        struct alt_base *newalt;
 544                        char *target = NULL;
 545                        if (data[i] == '/') {
 546                                /*
 547                                 * This counts
 548                                 * http://git.host/pub/scm/linux.git/
 549                                 * -----------here^
 550                                 * so memcpy(dst, base, serverlen) will
 551                                 * copy up to "...git.host".
 552                                 */
 553                                const char *colon_ss = strstr(base,"://");
 554                                if (colon_ss) {
 555                                        serverlen = (strchr(colon_ss + 3, '/')
 556                                                     - base);
 557                                        okay = 1;
 558                                }
 559                        } else if (!memcmp(data + i, "../", 3)) {
 560                                /*
 561                                 * Relative URL; chop the corresponding
 562                                 * number of subpath from base (and ../
 563                                 * from data), and concatenate the result.
 564                                 *
 565                                 * The code first drops ../ from data, and
 566                                 * then drops one ../ from data and one path
 567                                 * from base.  IOW, one extra ../ is dropped
 568                                 * from data than path is dropped from base.
 569                                 *
 570                                 * This is not wrong.  The alternate in
 571                                 *     http://git.host/pub/scm/linux.git/
 572                                 * to borrow from
 573                                 *     http://git.host/pub/scm/linus.git/
 574                                 * is ../../linus.git/objects/.  You need
 575                                 * two ../../ to borrow from your direct
 576                                 * neighbour.
 577                                 */
 578                                i += 3;
 579                                serverlen = strlen(base);
 580                                while (i + 2 < posn &&
 581                                       !memcmp(data + i, "../", 3)) {
 582                                        do {
 583                                                serverlen--;
 584                                        } while (serverlen &&
 585                                                 base[serverlen - 1] != '/');
 586                                        i += 3;
 587                                }
 588                                /* If the server got removed, give up. */
 589                                okay = strchr(base, ':') - base + 3 <
 590                                       serverlen;
 591                        } else if (alt_req->http_specific) {
 592                                char *colon = strchr(data + i, ':');
 593                                char *slash = strchr(data + i, '/');
 594                                if (colon && slash && colon < data + posn &&
 595                                    slash < data + posn && colon < slash) {
 596                                        okay = 1;
 597                                }
 598                        }
 599                        /* skip "objects\n" at end */
 600                        if (okay) {
 601                                target = xmalloc(serverlen + posn - i - 6);
 602                                memcpy(target, base, serverlen);
 603                                memcpy(target + serverlen, data + i,
 604                                       posn - i - 7);
 605                                target[serverlen + posn - i - 7] = 0;
 606                                if (walker->get_verbosely)
 607                                        fprintf(stderr,
 608                                                "Also look at %s\n", target);
 609                                newalt = xmalloc(sizeof(*newalt));
 610                                newalt->next = NULL;
 611                                newalt->base = target;
 612                                newalt->got_indices = 0;
 613                                newalt->packs = NULL;
 614
 615                                while (tail->next != NULL)
 616                                        tail = tail->next;
 617                                tail->next = newalt;
 618                        }
 619                }
 620                i = posn + 1;
 621        }
 622
 623        cdata->got_alternates = 1;
 624}
 625
 626static void fetch_alternates(struct walker *walker, const char *base)
 627{
 628        struct strbuf buffer = STRBUF_INIT;
 629        char *url;
 630        struct active_request_slot *slot;
 631        struct alternates_request alt_req;
 632        struct walker_data *cdata = walker->data;
 633
 634        /*
 635         * If another request has already started fetching alternates,
 636         * wait for them to arrive and return to processing this request's
 637         * curl message
 638         */
 639#ifdef USE_CURL_MULTI
 640        while (cdata->got_alternates == 0) {
 641                step_active_slots();
 642        }
 643#endif
 644
 645        /* Nothing to do if they've already been fetched */
 646        if (cdata->got_alternates == 1)
 647                return;
 648
 649        /* Start the fetch */
 650        cdata->got_alternates = 0;
 651
 652        if (walker->get_verbosely)
 653                fprintf(stderr, "Getting alternates list for %s\n", base);
 654
 655        url = xmalloc(strlen(base) + 31);
 656        sprintf(url, "%s/objects/info/http-alternates", base);
 657
 658        /*
 659         * Use a callback to process the result, since another request
 660         * may fail and need to have alternates loaded before continuing
 661         */
 662        slot = get_active_slot();
 663        slot->callback_func = process_alternates_response;
 664        alt_req.walker = walker;
 665        slot->callback_data = &alt_req;
 666
 667        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 668        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 669        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 670
 671        alt_req.base = base;
 672        alt_req.url = url;
 673        alt_req.buffer = &buffer;
 674        alt_req.http_specific = 1;
 675        alt_req.slot = slot;
 676
 677        if (start_active_slot(slot))
 678                run_active_slot(slot);
 679        else
 680                cdata->got_alternates = -1;
 681
 682        strbuf_release(&buffer);
 683        free(url);
 684}
 685
 686static int fetch_indices(struct walker *walker, struct alt_base *repo)
 687{
 688        unsigned char sha1[20];
 689        char *url;
 690        struct strbuf buffer = STRBUF_INIT;
 691        char *data;
 692        int i = 0;
 693        int ret = 0;
 694
 695        struct active_request_slot *slot;
 696        struct slot_results results;
 697
 698        if (repo->got_indices)
 699                return 0;
 700
 701        if (walker->get_verbosely)
 702                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 703
 704        url = xmalloc(strlen(repo->base) + 21);
 705        sprintf(url, "%s/objects/info/packs", repo->base);
 706
 707        slot = get_active_slot();
 708        slot->results = &results;
 709        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 710        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 711        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 712        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 713        if (start_active_slot(slot)) {
 714                run_active_slot(slot);
 715                if (results.curl_result != CURLE_OK) {
 716                        if (missing_target(&results)) {
 717                                repo->got_indices = 1;
 718                                goto cleanup;
 719                        } else {
 720                                repo->got_indices = 0;
 721                                ret = error("%s", curl_errorstr);
 722                                goto cleanup;
 723                        }
 724                }
 725        } else {
 726                repo->got_indices = 0;
 727                ret = error("Unable to start request");
 728                goto cleanup;
 729        }
 730
 731        data = buffer.buf;
 732        while (i < buffer.len) {
 733                switch (data[i]) {
 734                case 'P':
 735                        i++;
 736                        if (i + 52 <= buffer.len &&
 737                            !prefixcmp(data + i, " pack-") &&
 738                            !prefixcmp(data + i + 46, ".pack\n")) {
 739                                get_sha1_hex(data + i + 6, sha1);
 740                                setup_index(walker, repo, sha1);
 741                                i += 51;
 742                                break;
 743                        }
 744                default:
 745                        while (i < buffer.len && data[i] != '\n')
 746                                i++;
 747                }
 748                i++;
 749        }
 750
 751        repo->got_indices = 1;
 752cleanup:
 753        strbuf_release(&buffer);
 754        free(url);
 755        return ret;
 756}
 757
 758static int fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 759{
 760        char *url;
 761        struct packed_git *target;
 762        struct packed_git **lst;
 763        FILE *packfile;
 764        char *filename;
 765        char tmpfile[PATH_MAX];
 766        int ret;
 767        long prev_posn = 0;
 768        char range[RANGE_HEADER_SIZE];
 769        struct curl_slist *range_header = NULL;
 770        struct walker_data *data = walker->data;
 771
 772        struct active_request_slot *slot;
 773        struct slot_results results;
 774
 775        if (fetch_indices(walker, repo))
 776                return -1;
 777        target = find_sha1_pack(sha1, repo->packs);
 778        if (!target)
 779                return -1;
 780
 781        if (walker->get_verbosely) {
 782                fprintf(stderr, "Getting pack %s\n",
 783                        sha1_to_hex(target->sha1));
 784                fprintf(stderr, " which contains %s\n",
 785                        sha1_to_hex(sha1));
 786        }
 787
 788        url = xmalloc(strlen(repo->base) + 65);
 789        sprintf(url, "%s/objects/pack/pack-%s.pack",
 790                repo->base, sha1_to_hex(target->sha1));
 791
 792        filename = sha1_pack_name(target->sha1);
 793        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 794        packfile = fopen(tmpfile, "a");
 795        if (!packfile)
 796                return error("Unable to open local file %s for pack",
 797                             tmpfile);
 798
 799        slot = get_active_slot();
 800        slot->results = &results;
 801        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 802        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 803        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 804        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 805        slot->local = packfile;
 806
 807        /*
 808         * If there is data present from a previous transfer attempt,
 809         * resume where it left off
 810         */
 811        prev_posn = ftell(packfile);
 812        if (prev_posn>0) {
 813                if (walker->get_verbosely)
 814                        fprintf(stderr,
 815                                "Resuming fetch of pack %s at byte %ld\n",
 816                                sha1_to_hex(target->sha1), prev_posn);
 817                sprintf(range, "Range: bytes=%ld-", prev_posn);
 818                range_header = curl_slist_append(range_header, range);
 819                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 820        }
 821
 822        if (start_active_slot(slot)) {
 823                run_active_slot(slot);
 824                if (results.curl_result != CURLE_OK) {
 825                        fclose(packfile);
 826                        slot->local = NULL;
 827                        return error("Unable to get pack file %s\n%s", url,
 828                                     curl_errorstr);
 829                }
 830        } else {
 831                fclose(packfile);
 832                slot->local = NULL;
 833                return error("Unable to start request");
 834        }
 835
 836        target->pack_size = ftell(packfile);
 837        fclose(packfile);
 838        slot->local = NULL;
 839
 840        ret = move_temp_to_file(tmpfile, filename);
 841        if (ret)
 842                return ret;
 843
 844        lst = &repo->packs;
 845        while (*lst != target)
 846                lst = &((*lst)->next);
 847        *lst = (*lst)->next;
 848
 849        if (verify_pack(target))
 850                return -1;
 851        install_packed_git(target);
 852
 853        return 0;
 854}
 855
 856static void abort_object_request(struct object_request *obj_req)
 857{
 858        if (obj_req->local >= 0) {
 859                close(obj_req->local);
 860                obj_req->local = -1;
 861        }
 862        unlink_or_warn(obj_req->tmpfile);
 863        if (obj_req->slot) {
 864                release_active_slot(obj_req->slot);
 865                obj_req->slot = NULL;
 866        }
 867        release_object_request(obj_req);
 868}
 869
 870static int fetch_object(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 871{
 872        char *hex = sha1_to_hex(sha1);
 873        int ret = 0;
 874        struct object_request *obj_req = object_queue_head;
 875
 876        while (obj_req != NULL && hashcmp(obj_req->sha1, sha1))
 877                obj_req = obj_req->next;
 878        if (obj_req == NULL)
 879                return error("Couldn't find request for %s in the queue", hex);
 880
 881        if (has_sha1_file(obj_req->sha1)) {
 882                abort_object_request(obj_req);
 883                return 0;
 884        }
 885
 886#ifdef USE_CURL_MULTI
 887        while (obj_req->state == WAITING)
 888                step_active_slots();
 889#else
 890        start_object_request(walker, obj_req);
 891#endif
 892
 893        while (obj_req->state == ACTIVE)
 894                run_active_slot(obj_req->slot);
 895
 896        if (obj_req->local != -1) {
 897                close(obj_req->local);
 898                obj_req->local = -1;
 899        }
 900
 901        if (obj_req->state == ABORTED) {
 902                ret = error("Request for %s aborted", hex);
 903        } else if (obj_req->curl_result != CURLE_OK &&
 904                   obj_req->http_code != 416) {
 905                if (missing_target(obj_req))
 906                        ret = -1; /* Be silent, it is probably in a pack. */
 907                else
 908                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 909                                    obj_req->errorstr, obj_req->curl_result,
 910                                    obj_req->http_code, hex);
 911        } else if (obj_req->zret != Z_STREAM_END) {
 912                walker->corrupt_object_found++;
 913                ret = error("File %s (%s) corrupt", hex, obj_req->url);
 914        } else if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
 915                ret = error("File %s has bad hash", hex);
 916        } else if (obj_req->rename < 0) {
 917                ret = error("unable to write sha1 filename %s",
 918                            obj_req->filename);
 919        }
 920
 921        release_object_request(obj_req);
 922        return ret;
 923}
 924
 925static int fetch(struct walker *walker, unsigned char *sha1)
 926{
 927        struct walker_data *data = walker->data;
 928        struct alt_base *altbase = data->alt;
 929
 930        if (!fetch_object(walker, altbase, sha1))
 931                return 0;
 932        while (altbase) {
 933                if (!fetch_pack(walker, altbase, sha1))
 934                        return 0;
 935                fetch_alternates(walker, data->alt->base);
 936                altbase = altbase->next;
 937        }
 938        return error("Unable to find %s under %s", sha1_to_hex(sha1),
 939                     data->alt->base);
 940}
 941
 942static int fetch_ref(struct walker *walker, struct ref *ref)
 943{
 944        struct walker_data *data = walker->data;
 945        return http_fetch_ref(data->alt->base, ref);
 946}
 947
 948static void cleanup(struct walker *walker)
 949{
 950        struct walker_data *data = walker->data;
 951        http_cleanup();
 952
 953        curl_slist_free_all(data->no_pragma_header);
 954}
 955
 956struct walker *get_http_walker(const char *url, struct remote *remote)
 957{
 958        char *s;
 959        struct walker_data *data = xmalloc(sizeof(struct walker_data));
 960        struct walker *walker = xmalloc(sizeof(struct walker));
 961
 962        http_init(remote);
 963
 964        data->no_pragma_header = curl_slist_append(NULL, "Pragma:");
 965
 966        data->alt = xmalloc(sizeof(*data->alt));
 967        data->alt->base = xmalloc(strlen(url) + 1);
 968        strcpy(data->alt->base, url);
 969        for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 970                *s = 0;
 971
 972        data->alt->got_indices = 0;
 973        data->alt->packs = NULL;
 974        data->alt->next = NULL;
 975        data->got_alternates = -1;
 976
 977        walker->corrupt_object_found = 0;
 978        walker->fetch = fetch;
 979        walker->fetch_ref = fetch_ref;
 980        walker->prefetch = prefetch;
 981        walker->cleanup = cleanup;
 982        walker->data = data;
 983
 984#ifdef USE_CURL_MULTI
 985        add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 986#endif
 987
 988        return walker;
 989}