Andrew's git / gitweb.git / http-walker.c
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http-walker.con commit Ensure builtin-fetch honors {fetch,transfer}.unpackLimit (50ab5fd)
   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        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 buffer *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 = inflate(&obj_req->stream, Z_SYNC_FLUSH);
  86                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 int missing__target(int code, int result)
  94{
  95        return  /* file:// URL -- do we ever use one??? */
  96                (result == CURLE_FILE_COULDNT_READ_FILE) ||
  97                /* http:// and https:// URL */
  98                (code == 404 && result == CURLE_HTTP_RETURNED_ERROR) ||
  99                /* ftp:// URL */
 100                (code == 550 && result == CURLE_FTP_COULDNT_RETR_FILE)
 101                ;
 102}
 103
 104#define missing_target(a) missing__target((a)->http_code, (a)->curl_result)
 105
 106static void fetch_alternates(struct walker *walker, const char *base);
 107
 108static void process_object_response(void *callback_data);
 109
 110static void start_object_request(struct walker *walker,
 111                                 struct object_request *obj_req)
 112{
 113        char *hex = sha1_to_hex(obj_req->sha1);
 114        char prevfile[PATH_MAX];
 115        char *url;
 116        char *posn;
 117        int prevlocal;
 118        unsigned char prev_buf[PREV_BUF_SIZE];
 119        ssize_t prev_read = 0;
 120        long prev_posn = 0;
 121        char range[RANGE_HEADER_SIZE];
 122        struct curl_slist *range_header = NULL;
 123        struct active_request_slot *slot;
 124        struct walker_data *data = walker->data;
 125
 126        snprintf(prevfile, sizeof(prevfile), "%s.prev", obj_req->filename);
 127        unlink(prevfile);
 128        rename(obj_req->tmpfile, prevfile);
 129        unlink(obj_req->tmpfile);
 130
 131        if (obj_req->local != -1)
 132                error("fd leakage in start: %d", obj_req->local);
 133        obj_req->local = open(obj_req->tmpfile,
 134                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 135        /* This could have failed due to the "lazy directory creation";
 136         * try to mkdir the last path component.
 137         */
 138        if (obj_req->local < 0 && errno == ENOENT) {
 139                char *dir = strrchr(obj_req->tmpfile, '/');
 140                if (dir) {
 141                        *dir = 0;
 142                        mkdir(obj_req->tmpfile, 0777);
 143                        *dir = '/';
 144                }
 145                obj_req->local = open(obj_req->tmpfile,
 146                                      O_WRONLY | O_CREAT | O_EXCL, 0666);
 147        }
 148
 149        if (obj_req->local < 0) {
 150                obj_req->state = ABORTED;
 151                error("Couldn't create temporary file %s for %s: %s",
 152                      obj_req->tmpfile, obj_req->filename, strerror(errno));
 153                return;
 154        }
 155
 156        memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 157
 158        inflateInit(&obj_req->stream);
 159
 160        SHA1_Init(&obj_req->c);
 161
 162        url = xmalloc(strlen(obj_req->repo->base) + 51);
 163        obj_req->url = xmalloc(strlen(obj_req->repo->base) + 51);
 164        strcpy(url, obj_req->repo->base);
 165        posn = url + strlen(obj_req->repo->base);
 166        strcpy(posn, "/objects/");
 167        posn += 9;
 168        memcpy(posn, hex, 2);
 169        posn += 2;
 170        *(posn++) = '/';
 171        strcpy(posn, hex + 2);
 172        strcpy(obj_req->url, url);
 173
 174        /* If a previous temp file is present, process what was already
 175           fetched. */
 176        prevlocal = open(prevfile, O_RDONLY);
 177        if (prevlocal != -1) {
 178                do {
 179                        prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
 180                        if (prev_read>0) {
 181                                if (fwrite_sha1_file(prev_buf,
 182                                                     1,
 183                                                     prev_read,
 184                                                     obj_req) == prev_read) {
 185                                        prev_posn += prev_read;
 186                                } else {
 187                                        prev_read = -1;
 188                                }
 189                        }
 190                } while (prev_read > 0);
 191                close(prevlocal);
 192        }
 193        unlink(prevfile);
 194
 195        /* Reset inflate/SHA1 if there was an error reading the previous temp
 196           file; also rewind to the beginning of the local file. */
 197        if (prev_read == -1) {
 198                memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 199                inflateInit(&obj_req->stream);
 200                SHA1_Init(&obj_req->c);
 201                if (prev_posn>0) {
 202                        prev_posn = 0;
 203                        lseek(obj_req->local, 0, SEEK_SET);
 204                        ftruncate(obj_req->local, 0);
 205                }
 206        }
 207
 208        slot = get_active_slot();
 209        slot->callback_func = process_object_response;
 210        slot->callback_data = obj_req;
 211        obj_req->slot = slot;
 212
 213        curl_easy_setopt(slot->curl, CURLOPT_FILE, obj_req);
 214        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 215        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, obj_req->errorstr);
 216        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 217        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 218
 219        /* If we have successfully processed data from a previous fetch
 220           attempt, only fetch the data we don't already have. */
 221        if (prev_posn>0) {
 222                if (walker->get_verbosely)
 223                        fprintf(stderr,
 224                                "Resuming fetch of object %s at byte %ld\n",
 225                                hex, prev_posn);
 226                sprintf(range, "Range: bytes=%ld-", prev_posn);
 227                range_header = curl_slist_append(range_header, range);
 228                curl_easy_setopt(slot->curl,
 229                                 CURLOPT_HTTPHEADER, range_header);
 230        }
 231
 232        /* Try to get the request started, abort the request on error */
 233        obj_req->state = ACTIVE;
 234        if (!start_active_slot(slot)) {
 235                obj_req->state = ABORTED;
 236                obj_req->slot = NULL;
 237                close(obj_req->local); obj_req->local = -1;
 238                free(obj_req->url);
 239                return;
 240        }
 241}
 242
 243static void finish_object_request(struct object_request *obj_req)
 244{
 245        struct stat st;
 246
 247        fchmod(obj_req->local, 0444);
 248        close(obj_req->local); obj_req->local = -1;
 249
 250        if (obj_req->http_code == 416) {
 251                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 252        } else if (obj_req->curl_result != CURLE_OK) {
 253                if (stat(obj_req->tmpfile, &st) == 0)
 254                        if (st.st_size == 0)
 255                                unlink(obj_req->tmpfile);
 256                return;
 257        }
 258
 259        inflateEnd(&obj_req->stream);
 260        SHA1_Final(obj_req->real_sha1, &obj_req->c);
 261        if (obj_req->zret != Z_STREAM_END) {
 262                unlink(obj_req->tmpfile);
 263                return;
 264        }
 265        if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
 266                unlink(obj_req->tmpfile);
 267                return;
 268        }
 269        obj_req->rename =
 270                move_temp_to_file(obj_req->tmpfile, obj_req->filename);
 271
 272        if (obj_req->rename == 0)
 273                walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
 274}
 275
 276static void process_object_response(void *callback_data)
 277{
 278        struct object_request *obj_req =
 279                (struct object_request *)callback_data;
 280        struct walker *walker = obj_req->walker;
 281        struct walker_data *data = walker->data;
 282        struct alt_base *alt = data->alt;
 283
 284        obj_req->curl_result = obj_req->slot->curl_result;
 285        obj_req->http_code = obj_req->slot->http_code;
 286        obj_req->slot = NULL;
 287        obj_req->state = COMPLETE;
 288
 289        /* Use alternates if necessary */
 290        if (missing_target(obj_req)) {
 291                fetch_alternates(walker, alt->base);
 292                if (obj_req->repo->next != NULL) {
 293                        obj_req->repo =
 294                                obj_req->repo->next;
 295                        close(obj_req->local);
 296                        obj_req->local = -1;
 297                        start_object_request(walker, obj_req);
 298                        return;
 299                }
 300        }
 301
 302        finish_object_request(obj_req);
 303}
 304
 305static void release_object_request(struct object_request *obj_req)
 306{
 307        struct object_request *entry = object_queue_head;
 308
 309        if (obj_req->local != -1)
 310                error("fd leakage in release: %d", obj_req->local);
 311        if (obj_req == object_queue_head) {
 312                object_queue_head = obj_req->next;
 313        } else {
 314                while (entry->next != NULL && entry->next != obj_req)
 315                        entry = entry->next;
 316                if (entry->next == obj_req)
 317                        entry->next = entry->next->next;
 318        }
 319
 320        free(obj_req->url);
 321        free(obj_req);
 322}
 323
 324#ifdef USE_CURL_MULTI
 325static int fill_active_slot(struct walker *walker)
 326{
 327        struct object_request *obj_req;
 328
 329        for (obj_req = object_queue_head; obj_req; obj_req = obj_req->next) {
 330                if (obj_req->state == WAITING) {
 331                        if (has_sha1_file(obj_req->sha1))
 332                                obj_req->state = COMPLETE;
 333                        else {
 334                                start_object_request(walker, obj_req);
 335                                return 1;
 336                        }
 337                }
 338        }
 339        return 0;
 340}
 341#endif
 342
 343static void prefetch(struct walker *walker, unsigned char *sha1)
 344{
 345        struct object_request *newreq;
 346        struct object_request *tail;
 347        struct walker_data *data = walker->data;
 348        char *filename = sha1_file_name(sha1);
 349
 350        newreq = xmalloc(sizeof(*newreq));
 351        newreq->walker = walker;
 352        hashcpy(newreq->sha1, sha1);
 353        newreq->repo = data->alt;
 354        newreq->url = NULL;
 355        newreq->local = -1;
 356        newreq->state = WAITING;
 357        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 358        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 359                 "%s.temp", filename);
 360        newreq->slot = NULL;
 361        newreq->next = NULL;
 362
 363        if (object_queue_head == NULL) {
 364                object_queue_head = newreq;
 365        } else {
 366                tail = object_queue_head;
 367                while (tail->next != NULL) {
 368                        tail = tail->next;
 369                }
 370                tail->next = newreq;
 371        }
 372
 373#ifdef USE_CURL_MULTI
 374        fill_active_slots();
 375        step_active_slots();
 376#endif
 377}
 378
 379static int fetch_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 380{
 381        char *hex = sha1_to_hex(sha1);
 382        char *filename;
 383        char *url;
 384        char tmpfile[PATH_MAX];
 385        long prev_posn = 0;
 386        char range[RANGE_HEADER_SIZE];
 387        struct curl_slist *range_header = NULL;
 388        struct walker_data *data = walker->data;
 389
 390        FILE *indexfile;
 391        struct active_request_slot *slot;
 392        struct slot_results results;
 393
 394        if (has_pack_index(sha1))
 395                return 0;
 396
 397        if (walker->get_verbosely)
 398                fprintf(stderr, "Getting index for pack %s\n", hex);
 399
 400        url = xmalloc(strlen(repo->base) + 64);
 401        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 402
 403        filename = sha1_pack_index_name(sha1);
 404        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 405        indexfile = fopen(tmpfile, "a");
 406        if (!indexfile)
 407                return error("Unable to open local file %s for pack index",
 408                             filename);
 409
 410        slot = get_active_slot();
 411        slot->results = &results;
 412        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 413        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 414        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 415        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 416        slot->local = indexfile;
 417
 418        /* If there is data present from a previous transfer attempt,
 419           resume where it left off */
 420        prev_posn = ftell(indexfile);
 421        if (prev_posn>0) {
 422                if (walker->get_verbosely)
 423                        fprintf(stderr,
 424                                "Resuming fetch of index for pack %s at byte %ld\n",
 425                                hex, prev_posn);
 426                sprintf(range, "Range: bytes=%ld-", prev_posn);
 427                range_header = curl_slist_append(range_header, range);
 428                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 429        }
 430
 431        if (start_active_slot(slot)) {
 432                run_active_slot(slot);
 433                if (results.curl_result != CURLE_OK) {
 434                        fclose(indexfile);
 435                        return error("Unable to get pack index %s\n%s", url,
 436                                     curl_errorstr);
 437                }
 438        } else {
 439                fclose(indexfile);
 440                return error("Unable to start request");
 441        }
 442
 443        fclose(indexfile);
 444
 445        return move_temp_to_file(tmpfile, filename);
 446}
 447
 448static int setup_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 449{
 450        struct packed_git *new_pack;
 451        if (has_pack_file(sha1))
 452                return 0; /* don't list this as something we can get */
 453
 454        if (fetch_index(walker, repo, sha1))
 455                return -1;
 456
 457        new_pack = parse_pack_index(sha1);
 458        new_pack->next = repo->packs;
 459        repo->packs = new_pack;
 460        return 0;
 461}
 462
 463static void process_alternates_response(void *callback_data)
 464{
 465        struct alternates_request *alt_req =
 466                (struct alternates_request *)callback_data;
 467        struct walker *walker = alt_req->walker;
 468        struct walker_data *cdata = walker->data;
 469        struct active_request_slot *slot = alt_req->slot;
 470        struct alt_base *tail = cdata->alt;
 471        const char *base = alt_req->base;
 472        static const char null_byte = '\0';
 473        char *data;
 474        int i = 0;
 475
 476        if (alt_req->http_specific) {
 477                if (slot->curl_result != CURLE_OK ||
 478                    !alt_req->buffer->posn) {
 479
 480                        /* Try reusing the slot to get non-http alternates */
 481                        alt_req->http_specific = 0;
 482                        sprintf(alt_req->url, "%s/objects/info/alternates",
 483                                base);
 484                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 485                                         alt_req->url);
 486                        active_requests++;
 487                        slot->in_use = 1;
 488                        if (slot->finished != NULL)
 489                                (*slot->finished) = 0;
 490                        if (!start_active_slot(slot)) {
 491                                cdata->got_alternates = -1;
 492                                slot->in_use = 0;
 493                                if (slot->finished != NULL)
 494                                        (*slot->finished) = 1;
 495                        }
 496                        return;
 497                }
 498        } else if (slot->curl_result != CURLE_OK) {
 499                if (!missing_target(slot)) {
 500                        cdata->got_alternates = -1;
 501                        return;
 502                }
 503        }
 504
 505        fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 506        alt_req->buffer->posn--;
 507        data = alt_req->buffer->buffer;
 508
 509        while (i < alt_req->buffer->posn) {
 510                int posn = i;
 511                while (posn < alt_req->buffer->posn && data[posn] != '\n')
 512                        posn++;
 513                if (data[posn] == '\n') {
 514                        int okay = 0;
 515                        int serverlen = 0;
 516                        struct alt_base *newalt;
 517                        char *target = NULL;
 518                        if (data[i] == '/') {
 519                                /* This counts
 520                                 * http://git.host/pub/scm/linux.git/
 521                                 * -----------here^
 522                                 * so memcpy(dst, base, serverlen) will
 523                                 * copy up to "...git.host".
 524                                 */
 525                                const char *colon_ss = strstr(base,"://");
 526                                if (colon_ss) {
 527                                        serverlen = (strchr(colon_ss + 3, '/')
 528                                                     - base);
 529                                        okay = 1;
 530                                }
 531                        } else if (!memcmp(data + i, "../", 3)) {
 532                                /* Relative URL; chop the corresponding
 533                                 * number of subpath from base (and ../
 534                                 * from data), and concatenate the result.
 535                                 *
 536                                 * The code first drops ../ from data, and
 537                                 * then drops one ../ from data and one path
 538                                 * from base.  IOW, one extra ../ is dropped
 539                                 * from data than path is dropped from base.
 540                                 *
 541                                 * This is not wrong.  The alternate in
 542                                 *     http://git.host/pub/scm/linux.git/
 543                                 * to borrow from
 544                                 *     http://git.host/pub/scm/linus.git/
 545                                 * is ../../linus.git/objects/.  You need
 546                                 * two ../../ to borrow from your direct
 547                                 * neighbour.
 548                                 */
 549                                i += 3;
 550                                serverlen = strlen(base);
 551                                while (i + 2 < posn &&
 552                                       !memcmp(data + i, "../", 3)) {
 553                                        do {
 554                                                serverlen--;
 555                                        } while (serverlen &&
 556                                                 base[serverlen - 1] != '/');
 557                                        i += 3;
 558                                }
 559                                /* If the server got removed, give up. */
 560                                okay = strchr(base, ':') - base + 3 <
 561                                        serverlen;
 562                        } else if (alt_req->http_specific) {
 563                                char *colon = strchr(data + i, ':');
 564                                char *slash = strchr(data + i, '/');
 565                                if (colon && slash && colon < data + posn &&
 566                                    slash < data + posn && colon < slash) {
 567                                        okay = 1;
 568                                }
 569                        }
 570                        /* skip "objects\n" at end */
 571                        if (okay) {
 572                                target = xmalloc(serverlen + posn - i - 6);
 573                                memcpy(target, base, serverlen);
 574                                memcpy(target + serverlen, data + i,
 575                                       posn - i - 7);
 576                                target[serverlen + posn - i - 7] = 0;
 577                                if (walker->get_verbosely)
 578                                        fprintf(stderr,
 579                                                "Also look at %s\n", target);
 580                                newalt = xmalloc(sizeof(*newalt));
 581                                newalt->next = NULL;
 582                                newalt->base = target;
 583                                newalt->got_indices = 0;
 584                                newalt->packs = NULL;
 585
 586                                while (tail->next != NULL)
 587                                        tail = tail->next;
 588                                tail->next = newalt;
 589                        }
 590                }
 591                i = posn + 1;
 592        }
 593
 594        cdata->got_alternates = 1;
 595}
 596
 597static void fetch_alternates(struct walker *walker, const char *base)
 598{
 599        struct buffer buffer;
 600        char *url;
 601        char *data;
 602        struct active_request_slot *slot;
 603        struct alternates_request alt_req;
 604        struct walker_data *cdata = walker->data;
 605
 606        /* If another request has already started fetching alternates,
 607           wait for them to arrive and return to processing this request's
 608           curl message */
 609#ifdef USE_CURL_MULTI
 610        while (cdata->got_alternates == 0) {
 611                step_active_slots();
 612        }
 613#endif
 614
 615        /* Nothing to do if they've already been fetched */
 616        if (cdata->got_alternates == 1)
 617                return;
 618
 619        /* Start the fetch */
 620        cdata->got_alternates = 0;
 621
 622        data = xmalloc(4096);
 623        buffer.size = 4096;
 624        buffer.posn = 0;
 625        buffer.buffer = data;
 626
 627        if (walker->get_verbosely)
 628                fprintf(stderr, "Getting alternates list for %s\n", base);
 629
 630        url = xmalloc(strlen(base) + 31);
 631        sprintf(url, "%s/objects/info/http-alternates", base);
 632
 633        /* Use a callback to process the result, since another request
 634           may fail and need to have alternates loaded before continuing */
 635        slot = get_active_slot();
 636        slot->callback_func = process_alternates_response;
 637        alt_req.walker = walker;
 638        slot->callback_data = &alt_req;
 639
 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
 644        alt_req.base = base;
 645        alt_req.url = url;
 646        alt_req.buffer = &buffer;
 647        alt_req.http_specific = 1;
 648        alt_req.slot = slot;
 649
 650        if (start_active_slot(slot))
 651                run_active_slot(slot);
 652        else
 653                cdata->got_alternates = -1;
 654
 655        free(data);
 656        free(url);
 657}
 658
 659static int fetch_indices(struct walker *walker, struct alt_base *repo)
 660{
 661        unsigned char sha1[20];
 662        char *url;
 663        struct buffer buffer;
 664        char *data;
 665        int i = 0;
 666
 667        struct active_request_slot *slot;
 668        struct slot_results results;
 669
 670        if (repo->got_indices)
 671                return 0;
 672
 673        data = xmalloc(4096);
 674        buffer.size = 4096;
 675        buffer.posn = 0;
 676        buffer.buffer = data;
 677
 678        if (walker->get_verbosely)
 679                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 680
 681        url = xmalloc(strlen(repo->base) + 21);
 682        sprintf(url, "%s/objects/info/packs", repo->base);
 683
 684        slot = get_active_slot();
 685        slot->results = &results;
 686        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 687        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 688        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 689        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 690        if (start_active_slot(slot)) {
 691                run_active_slot(slot);
 692                if (results.curl_result != CURLE_OK) {
 693                        if (missing_target(&results)) {
 694                                repo->got_indices = 1;
 695                                free(buffer.buffer);
 696                                return 0;
 697                        } else {
 698                                repo->got_indices = 0;
 699                                free(buffer.buffer);
 700                                return error("%s", curl_errorstr);
 701                        }
 702                }
 703        } else {
 704                repo->got_indices = 0;
 705                free(buffer.buffer);
 706                return error("Unable to start request");
 707        }
 708
 709        data = buffer.buffer;
 710        while (i < buffer.posn) {
 711                switch (data[i]) {
 712                case 'P':
 713                        i++;
 714                        if (i + 52 <= buffer.posn &&
 715                            !prefixcmp(data + i, " pack-") &&
 716                            !prefixcmp(data + i + 46, ".pack\n")) {
 717                                get_sha1_hex(data + i + 6, sha1);
 718                                setup_index(walker, repo, sha1);
 719                                i += 51;
 720                                break;
 721                        }
 722                default:
 723                        while (i < buffer.posn && data[i] != '\n')
 724                                i++;
 725                }
 726                i++;
 727        }
 728
 729        free(buffer.buffer);
 730        repo->got_indices = 1;
 731        return 0;
 732}
 733
 734static int fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 735{
 736        char *url;
 737        struct packed_git *target;
 738        struct packed_git **lst;
 739        FILE *packfile;
 740        char *filename;
 741        char tmpfile[PATH_MAX];
 742        int ret;
 743        long prev_posn = 0;
 744        char range[RANGE_HEADER_SIZE];
 745        struct curl_slist *range_header = NULL;
 746        struct walker_data *data = walker->data;
 747
 748        struct active_request_slot *slot;
 749        struct slot_results results;
 750
 751        if (fetch_indices(walker, repo))
 752                return -1;
 753        target = find_sha1_pack(sha1, repo->packs);
 754        if (!target)
 755                return -1;
 756
 757        if (walker->get_verbosely) {
 758                fprintf(stderr, "Getting pack %s\n",
 759                        sha1_to_hex(target->sha1));
 760                fprintf(stderr, " which contains %s\n",
 761                        sha1_to_hex(sha1));
 762        }
 763
 764        url = xmalloc(strlen(repo->base) + 65);
 765        sprintf(url, "%s/objects/pack/pack-%s.pack",
 766                repo->base, sha1_to_hex(target->sha1));
 767
 768        filename = sha1_pack_name(target->sha1);
 769        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 770        packfile = fopen(tmpfile, "a");
 771        if (!packfile)
 772                return error("Unable to open local file %s for pack",
 773                             filename);
 774
 775        slot = get_active_slot();
 776        slot->results = &results;
 777        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 778        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 779        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 780        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 781        slot->local = packfile;
 782
 783        /* If there is data present from a previous transfer attempt,
 784           resume where it left off */
 785        prev_posn = ftell(packfile);
 786        if (prev_posn>0) {
 787                if (walker->get_verbosely)
 788                        fprintf(stderr,
 789                                "Resuming fetch of pack %s at byte %ld\n",
 790                                sha1_to_hex(target->sha1), prev_posn);
 791                sprintf(range, "Range: bytes=%ld-", prev_posn);
 792                range_header = curl_slist_append(range_header, range);
 793                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 794        }
 795
 796        if (start_active_slot(slot)) {
 797                run_active_slot(slot);
 798                if (results.curl_result != CURLE_OK) {
 799                        fclose(packfile);
 800                        return error("Unable to get pack file %s\n%s", url,
 801                                     curl_errorstr);
 802                }
 803        } else {
 804                fclose(packfile);
 805                return error("Unable to start request");
 806        }
 807
 808        target->pack_size = ftell(packfile);
 809        fclose(packfile);
 810
 811        ret = move_temp_to_file(tmpfile, filename);
 812        if (ret)
 813                return ret;
 814
 815        lst = &repo->packs;
 816        while (*lst != target)
 817                lst = &((*lst)->next);
 818        *lst = (*lst)->next;
 819
 820        if (verify_pack(target, 0))
 821                return -1;
 822        install_packed_git(target);
 823
 824        return 0;
 825}
 826
 827static void abort_object_request(struct object_request *obj_req)
 828{
 829        if (obj_req->local >= 0) {
 830                close(obj_req->local);
 831                obj_req->local = -1;
 832        }
 833        unlink(obj_req->tmpfile);
 834        if (obj_req->slot) {
 835                release_active_slot(obj_req->slot);
 836                obj_req->slot = NULL;
 837        }
 838        release_object_request(obj_req);
 839}
 840
 841static int fetch_object(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 842{
 843        char *hex = sha1_to_hex(sha1);
 844        int ret = 0;
 845        struct object_request *obj_req = object_queue_head;
 846
 847        while (obj_req != NULL && hashcmp(obj_req->sha1, sha1))
 848                obj_req = obj_req->next;
 849        if (obj_req == NULL)
 850                return error("Couldn't find request for %s in the queue", hex);
 851
 852        if (has_sha1_file(obj_req->sha1)) {
 853                abort_object_request(obj_req);
 854                return 0;
 855        }
 856
 857#ifdef USE_CURL_MULTI
 858        while (obj_req->state == WAITING) {
 859                step_active_slots();
 860        }
 861#else
 862        start_object_request(walker, obj_req);
 863#endif
 864
 865        while (obj_req->state == ACTIVE) {
 866                run_active_slot(obj_req->slot);
 867        }
 868        if (obj_req->local != -1) {
 869                close(obj_req->local); obj_req->local = -1;
 870        }
 871
 872        if (obj_req->state == ABORTED) {
 873                ret = error("Request for %s aborted", hex);
 874        } else if (obj_req->curl_result != CURLE_OK &&
 875                   obj_req->http_code != 416) {
 876                if (missing_target(obj_req))
 877                        ret = -1; /* Be silent, it is probably in a pack. */
 878                else
 879                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 880                                    obj_req->errorstr, obj_req->curl_result,
 881                                    obj_req->http_code, hex);
 882        } else if (obj_req->zret != Z_STREAM_END) {
 883                walker->corrupt_object_found++;
 884                ret = error("File %s (%s) corrupt", hex, obj_req->url);
 885        } else if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
 886                ret = error("File %s has bad hash", hex);
 887        } else if (obj_req->rename < 0) {
 888                ret = error("unable to write sha1 filename %s",
 889                            obj_req->filename);
 890        }
 891
 892        release_object_request(obj_req);
 893        return ret;
 894}
 895
 896static int fetch(struct walker *walker, unsigned char *sha1)
 897{
 898        struct walker_data *data = walker->data;
 899        struct alt_base *altbase = data->alt;
 900
 901        if (!fetch_object(walker, altbase, sha1))
 902                return 0;
 903        while (altbase) {
 904                if (!fetch_pack(walker, altbase, sha1))
 905                        return 0;
 906                fetch_alternates(walker, data->alt->base);
 907                altbase = altbase->next;
 908        }
 909        return error("Unable to find %s under %s", sha1_to_hex(sha1),
 910                     data->alt->base);
 911}
 912
 913static inline int needs_quote(int ch)
 914{
 915        if (((ch >= 'A') && (ch <= 'Z'))
 916                        || ((ch >= 'a') && (ch <= 'z'))
 917                        || ((ch >= '0') && (ch <= '9'))
 918                        || (ch == '/')
 919                        || (ch == '-')
 920                        || (ch == '.'))
 921                return 0;
 922        return 1;
 923}
 924
 925static inline int hex(int v)
 926{
 927        if (v < 10) return '0' + v;
 928        else return 'A' + v - 10;
 929}
 930
 931static char *quote_ref_url(const char *base, const char *ref)
 932{
 933        const char *cp;
 934        char *dp, *qref;
 935        int len, baselen, ch;
 936
 937        baselen = strlen(base);
 938        len = baselen + 7; /* "/refs/" + NUL */
 939        for (cp = ref; (ch = *cp) != 0; cp++, len++)
 940                if (needs_quote(ch))
 941                        len += 2; /* extra two hex plus replacement % */
 942        qref = xmalloc(len);
 943        memcpy(qref, base, baselen);
 944        memcpy(qref + baselen, "/refs/", 6);
 945        for (cp = ref, dp = qref + baselen + 6; (ch = *cp) != 0; cp++) {
 946                if (needs_quote(ch)) {
 947                        *dp++ = '%';
 948                        *dp++ = hex((ch >> 4) & 0xF);
 949                        *dp++ = hex(ch & 0xF);
 950                }
 951                else
 952                        *dp++ = ch;
 953        }
 954        *dp = 0;
 955
 956        return qref;
 957}
 958
 959static int fetch_ref(struct walker *walker, char *ref, unsigned char *sha1)
 960{
 961        char *url;
 962        char hex[42];
 963        struct buffer buffer;
 964        struct walker_data *data = walker->data;
 965        const char *base = data->alt->base;
 966        struct active_request_slot *slot;
 967        struct slot_results results;
 968        buffer.size = 41;
 969        buffer.posn = 0;
 970        buffer.buffer = hex;
 971        hex[41] = '\0';
 972
 973        url = quote_ref_url(base, ref);
 974        slot = get_active_slot();
 975        slot->results = &results;
 976        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 977        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 978        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 979        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 980        if (start_active_slot(slot)) {
 981                run_active_slot(slot);
 982                if (results.curl_result != CURLE_OK)
 983                        return error("Couldn't get %s for %s\n%s",
 984                                     url, ref, curl_errorstr);
 985        } else {
 986                return error("Unable to start request");
 987        }
 988
 989        hex[40] = '\0';
 990        get_sha1_hex(hex, sha1);
 991        return 0;
 992}
 993
 994static void cleanup(struct walker *walker)
 995{
 996        struct walker_data *data = walker->data;
 997        http_cleanup();
 998
 999        curl_slist_free_all(data->no_pragma_header);
1000}
1001
1002struct walker *get_http_walker(const char *url)
1003{
1004        char *s;
1005        struct walker_data *data = xmalloc(sizeof(struct walker_data));
1006        struct walker *walker = xmalloc(sizeof(struct walker));
1007
1008        http_init();
1009
1010        data->no_pragma_header = curl_slist_append(NULL, "Pragma:");
1011
1012        data->alt = xmalloc(sizeof(*data->alt));
1013        data->alt->base = xmalloc(strlen(url) + 1);
1014        strcpy(data->alt->base, url);
1015        for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
1016                *s = 0;
1017
1018        data->alt->got_indices = 0;
1019        data->alt->packs = NULL;
1020        data->alt->next = NULL;
1021        data->got_alternates = -1;
1022
1023        walker->corrupt_object_found = 0;
1024        walker->fetch = fetch;
1025        walker->fetch_ref = fetch_ref;
1026        walker->prefetch = prefetch;
1027        walker->cleanup = cleanup;
1028        walker->data = data;
1029
1030#ifdef USE_CURL_MULTI
1031        add_fill_function(walker, (int (*)(void *)) fill_active_slot);
1032#endif
1033
1034        return walker;
1035}