Andrew's git / gitweb.git / http-fetch.c
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http-fetch.con commit http-fetch: Abort requests for objects which arrived in packs (53f3138)
   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\n",
 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 (!start_active_slot(slot)) {
 472                                got_alternates = -1;
 473                                slot->in_use = 0;
 474                        }
 475                        return;
 476                }
 477        } else if (slot->curl_result != CURLE_OK) {
 478                if (slot->http_code != 404 &&
 479                    slot->curl_result != CURLE_FILE_COULDNT_READ_FILE) {
 480                        got_alternates = -1;
 481                        return;
 482                }
 483        }
 484
 485        fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 486        alt_req->buffer->posn--;
 487        data = alt_req->buffer->buffer;
 488
 489        while (i < alt_req->buffer->posn) {
 490                int posn = i;
 491                while (posn < alt_req->buffer->posn && data[posn] != '\n')
 492                        posn++;
 493                if (data[posn] == '\n') {
 494                        int okay = 0;
 495                        int serverlen = 0;
 496                        struct alt_base *newalt;
 497                        char *target = NULL;
 498                        if (data[i] == '/') {
 499                                serverlen = strchr(base + 8, '/') - base;
 500                                okay = 1;
 501                        } else if (!memcmp(data + i, "../", 3)) {
 502                                i += 3;
 503                                serverlen = strlen(base);
 504                                while (i + 2 < posn &&
 505                                       !memcmp(data + i, "../", 3)) {
 506                                        do {
 507                                                serverlen--;
 508                                        } while (serverlen &&
 509                                                 base[serverlen - 1] != '/');
 510                                        i += 3;
 511                                }
 512                                // If the server got removed, give up.
 513                                okay = strchr(base, ':') - base + 3 <
 514                                        serverlen;
 515                        } else if (alt_req->http_specific) {
 516                                char *colon = strchr(data + i, ':');
 517                                char *slash = strchr(data + i, '/');
 518                                if (colon && slash && colon < data + posn &&
 519                                    slash < data + posn && colon < slash) {
 520                                        okay = 1;
 521                                }
 522                        }
 523                        // skip 'objects' at end
 524                        if (okay) {
 525                                target = xmalloc(serverlen + posn - i - 6);
 526                                strncpy(target, base, serverlen);
 527                                strncpy(target + serverlen, data + i,
 528                                        posn - i - 7);
 529                                target[serverlen + posn - i - 7] = '\0';
 530                                if (get_verbosely)
 531                                        fprintf(stderr,
 532                                                "Also look at %s\n", target);
 533                                newalt = xmalloc(sizeof(*newalt));
 534                                newalt->next = NULL;
 535                                newalt->base = target;
 536                                newalt->got_indices = 0;
 537                                newalt->packs = NULL;
 538                                while (tail->next != NULL)
 539                                        tail = tail->next;
 540                                tail->next = newalt;
 541                        }
 542                }
 543                i = posn + 1;
 544        }
 545
 546        got_alternates = 1;
 547}
 548
 549static void fetch_alternates(char *base)
 550{
 551        struct buffer buffer;
 552        char *url;
 553        char *data;
 554        struct active_request_slot *slot;
 555        struct alternates_request alt_req;
 556
 557        /* If another request has already started fetching alternates,
 558           wait for them to arrive and return to processing this request's
 559           curl message */
 560#ifdef USE_CURL_MULTI
 561        while (got_alternates == 0) {
 562                step_active_slots();
 563        }
 564#endif
 565
 566        /* Nothing to do if they've already been fetched */
 567        if (got_alternates == 1)
 568                return;
 569
 570        /* Start the fetch */
 571        got_alternates = 0;
 572
 573        data = xmalloc(4096);
 574        buffer.size = 4096;
 575        buffer.posn = 0;
 576        buffer.buffer = data;
 577
 578        if (get_verbosely)
 579                fprintf(stderr, "Getting alternates list for %s\n", base);
 580
 581        url = xmalloc(strlen(base) + 31);
 582        sprintf(url, "%s/objects/info/http-alternates", base);
 583
 584        /* Use a callback to process the result, since another request
 585           may fail and need to have alternates loaded before continuing */
 586        slot = get_active_slot();
 587        slot->callback_func = process_alternates_response;
 588        slot->callback_data = &alt_req;
 589
 590        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 591        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 592        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 593
 594        alt_req.base = base;
 595        alt_req.url = url;
 596        alt_req.buffer = &buffer;
 597        alt_req.http_specific = 1;
 598        alt_req.slot = slot;
 599
 600        if (start_active_slot(slot))
 601                run_active_slot(slot);
 602        else
 603                got_alternates = -1;
 604
 605        free(data);
 606        free(url);
 607}
 608
 609static int fetch_indices(struct alt_base *repo)
 610{
 611        unsigned char sha1[20];
 612        char *url;
 613        struct buffer buffer;
 614        char *data;
 615        int i = 0;
 616
 617        struct active_request_slot *slot;
 618        struct slot_results results;
 619
 620        if (repo->got_indices)
 621                return 0;
 622
 623        data = xmalloc(4096);
 624        buffer.size = 4096;
 625        buffer.posn = 0;
 626        buffer.buffer = data;
 627
 628        if (get_verbosely)
 629                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 630
 631        url = xmalloc(strlen(repo->base) + 21);
 632        sprintf(url, "%s/objects/info/packs", repo->base);
 633
 634        slot = get_active_slot();
 635        slot->results = &results;
 636        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 637        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 638        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 639        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 640        if (start_active_slot(slot)) {
 641                run_active_slot(slot);
 642                if (results.curl_result != CURLE_OK) {
 643                        if (results.http_code == 404 ||
 644                            results.curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 645                                repo->got_indices = 1;
 646                                free(buffer.buffer);
 647                                return 0;
 648                        } else {
 649                                repo->got_indices = 0;
 650                                free(buffer.buffer);
 651                                return error("%s", curl_errorstr);
 652                        }
 653                }
 654        } else {
 655                repo->got_indices = 0;
 656                free(buffer.buffer);
 657                return error("Unable to start request");
 658        }
 659
 660        data = buffer.buffer;
 661        while (i < buffer.posn) {
 662                switch (data[i]) {
 663                case 'P':
 664                        i++;
 665                        if (i + 52 <= buffer.posn &&
 666                            !strncmp(data + i, " pack-", 6) &&
 667                            !strncmp(data + i + 46, ".pack\n", 6)) {
 668                                get_sha1_hex(data + i + 6, sha1);
 669                                setup_index(repo, sha1);
 670                                i += 51;
 671                                break;
 672                        }
 673                default:
 674                        while (i < buffer.posn && data[i] != '\n')
 675                                i++;
 676                }
 677                i++;
 678        }
 679
 680        free(buffer.buffer);
 681        repo->got_indices = 1;
 682        return 0;
 683}
 684
 685static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 686{
 687        char *url;
 688        struct packed_git *target;
 689        struct packed_git **lst;
 690        FILE *packfile;
 691        char *filename;
 692        char tmpfile[PATH_MAX];
 693        int ret;
 694        long prev_posn = 0;
 695        char range[RANGE_HEADER_SIZE];
 696        struct curl_slist *range_header = NULL;
 697
 698        struct active_request_slot *slot;
 699        struct slot_results results;
 700
 701        if (fetch_indices(repo))
 702                return -1;
 703        target = find_sha1_pack(sha1, repo->packs);
 704        if (!target)
 705                return -1;
 706
 707        if (get_verbosely) {
 708                fprintf(stderr, "Getting pack %s\n",
 709                        sha1_to_hex(target->sha1));
 710                fprintf(stderr, " which contains %s\n",
 711                        sha1_to_hex(sha1));
 712        }
 713
 714        url = xmalloc(strlen(repo->base) + 65);
 715        sprintf(url, "%s/objects/pack/pack-%s.pack",
 716                repo->base, sha1_to_hex(target->sha1));
 717
 718        filename = sha1_pack_name(target->sha1);
 719        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 720        packfile = fopen(tmpfile, "a");
 721        if (!packfile)
 722                return error("Unable to open local file %s for pack",
 723                             filename);
 724
 725        slot = get_active_slot();
 726        slot->results = &results;
 727        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 728        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 729        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 730        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 731        slot->local = packfile;
 732
 733        /* If there is data present from a previous transfer attempt,
 734           resume where it left off */
 735        prev_posn = ftell(packfile);
 736        if (prev_posn>0) {
 737                if (get_verbosely)
 738                        fprintf(stderr,
 739                                "Resuming fetch of pack %s at byte %ld\n",
 740                                sha1_to_hex(target->sha1), prev_posn);
 741                sprintf(range, "Range: bytes=%ld-", prev_posn);
 742                range_header = curl_slist_append(range_header, range);
 743                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 744        }
 745
 746        if (start_active_slot(slot)) {
 747                run_active_slot(slot);
 748                if (results.curl_result != CURLE_OK) {
 749                        fclose(packfile);
 750                        return error("Unable to get pack file %s\n%s", url,
 751                                     curl_errorstr);
 752                }
 753        } else {
 754                fclose(packfile);
 755                return error("Unable to start request");
 756        }
 757
 758        fclose(packfile);
 759
 760        ret = move_temp_to_file(tmpfile, filename);
 761        if (ret)
 762                return ret;
 763
 764        lst = &repo->packs;
 765        while (*lst != target)
 766                lst = &((*lst)->next);
 767        *lst = (*lst)->next;
 768
 769        if (verify_pack(target, 0))
 770                return -1;
 771        install_packed_git(target);
 772
 773        return 0;
 774}
 775
 776static void abort_object_request(struct object_request *obj_req)
 777{
 778        if (obj_req->local >= 0) {
 779                close(obj_req->local);
 780                obj_req->local = -1;
 781        }
 782        unlink(obj_req->tmpfile);
 783        if (obj_req->slot) {
 784                release_active_slot(obj_req->slot);
 785                obj_req->slot = NULL;
 786        }
 787        release_object_request(obj_req);
 788}
 789
 790static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 791{
 792        char *hex = sha1_to_hex(sha1);
 793        int ret = 0;
 794        struct object_request *obj_req = object_queue_head;
 795
 796        while (obj_req != NULL && memcmp(obj_req->sha1, sha1, 20))
 797                obj_req = obj_req->next;
 798        if (obj_req == NULL)
 799                return error("Couldn't find request for %s in the queue", hex);
 800
 801        if (has_sha1_file(obj_req->sha1)) {
 802                abort_object_request(obj_req);
 803                return 0;
 804        }
 805
 806#ifdef USE_CURL_MULTI
 807        while (obj_req->state == WAITING) {
 808                step_active_slots();
 809        }
 810#else
 811        start_object_request(obj_req);
 812#endif
 813
 814        while (obj_req->state == ACTIVE) {
 815                run_active_slot(obj_req->slot);
 816        }
 817        if (obj_req->local != -1) {
 818                close(obj_req->local); obj_req->local = -1;
 819        }
 820
 821        if (obj_req->state == ABORTED) {
 822                ret = error("Request for %s aborted", hex);
 823        } else if (obj_req->curl_result != CURLE_OK &&
 824                   obj_req->http_code != 416) {
 825                if (obj_req->http_code == 404 ||
 826                    obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE)
 827                        ret = -1; /* Be silent, it is probably in a pack. */
 828                else
 829                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 830                                    obj_req->errorstr, obj_req->curl_result,
 831                                    obj_req->http_code, hex);
 832        } else if (obj_req->zret != Z_STREAM_END) {
 833                ret = error("File %s (%s) corrupt\n", hex, obj_req->url);
 834        } else if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 835                ret = error("File %s has bad hash\n", hex);
 836        } else if (obj_req->rename < 0) {
 837                ret = error("unable to write sha1 filename %s",
 838                            obj_req->filename);
 839        }
 840
 841        release_object_request(obj_req);
 842        return ret;
 843}
 844
 845int fetch(unsigned char *sha1)
 846{
 847        struct alt_base *altbase = alt;
 848
 849        if (!fetch_object(altbase, sha1))
 850                return 0;
 851        while (altbase) {
 852                if (!fetch_pack(altbase, sha1))
 853                        return 0;
 854                fetch_alternates(alt->base);
 855                altbase = altbase->next;
 856        }
 857        return error("Unable to find %s under %s\n", sha1_to_hex(sha1),
 858                     alt->base);
 859}
 860
 861static inline int needs_quote(int ch)
 862{
 863        switch (ch) {
 864        case '/': case '-': case '.':
 865        case 'A'...'Z': case 'a'...'z': case '0'...'9':
 866                return 0;
 867        default:
 868                return 1;
 869        }
 870}
 871
 872static inline int hex(int v)
 873{
 874        if (v < 10) return '0' + v;
 875        else return 'A' + v - 10;
 876}
 877
 878static char *quote_ref_url(const char *base, const char *ref)
 879{
 880        const char *cp;
 881        char *dp, *qref;
 882        int len, baselen, ch;
 883
 884        baselen = strlen(base);
 885        len = baselen + 6; /* "refs/" + NUL */
 886        for (cp = ref; (ch = *cp) != 0; cp++, len++)
 887                if (needs_quote(ch))
 888                        len += 2; /* extra two hex plus replacement % */
 889        qref = xmalloc(len);
 890        memcpy(qref, base, baselen);
 891        memcpy(qref + baselen, "refs/", 5);
 892        for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
 893                if (needs_quote(ch)) {
 894                        *dp++ = '%';
 895                        *dp++ = hex((ch >> 4) & 0xF);
 896                        *dp++ = hex(ch & 0xF);
 897                }
 898                else
 899                        *dp++ = ch;
 900        }
 901        *dp = 0;
 902
 903        return qref;
 904}
 905
 906int fetch_ref(char *ref, unsigned char *sha1)
 907{
 908        char *url;
 909        char hex[42];
 910        struct buffer buffer;
 911        char *base = alt->base;
 912        struct active_request_slot *slot;
 913        struct slot_results results;
 914        buffer.size = 41;
 915        buffer.posn = 0;
 916        buffer.buffer = hex;
 917        hex[41] = '\0';
 918
 919        url = quote_ref_url(base, ref);
 920        slot = get_active_slot();
 921        slot->results = &results;
 922        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 923        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 924        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 925        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 926        if (start_active_slot(slot)) {
 927                run_active_slot(slot);
 928                if (results.curl_result != CURLE_OK)
 929                        return error("Couldn't get %s for %s\n%s",
 930                                     url, ref, curl_errorstr);
 931        } else {
 932                return error("Unable to start request");
 933        }
 934
 935        hex[40] = '\0';
 936        get_sha1_hex(hex, sha1);
 937        return 0;
 938}
 939
 940int main(int argc, char **argv)
 941{
 942        char *commit_id;
 943        char *url;
 944        int arg = 1;
 945        int rc = 0;
 946
 947        setup_git_directory();
 948
 949        while (arg < argc && argv[arg][0] == '-') {
 950                if (argv[arg][1] == 't') {
 951                        get_tree = 1;
 952                } else if (argv[arg][1] == 'c') {
 953                        get_history = 1;
 954                } else if (argv[arg][1] == 'a') {
 955                        get_all = 1;
 956                        get_tree = 1;
 957                        get_history = 1;
 958                } else if (argv[arg][1] == 'v') {
 959                        get_verbosely = 1;
 960                } else if (argv[arg][1] == 'w') {
 961                        write_ref = argv[arg + 1];
 962                        arg++;
 963                } else if (!strcmp(argv[arg], "--recover")) {
 964                        get_recover = 1;
 965                }
 966                arg++;
 967        }
 968        if (argc < arg + 2) {
 969                usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
 970                return 1;
 971        }
 972        commit_id = argv[arg];
 973        url = argv[arg + 1];
 974
 975        http_init();
 976
 977        no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 978
 979        alt = xmalloc(sizeof(*alt));
 980        alt->base = url;
 981        alt->got_indices = 0;
 982        alt->packs = NULL;
 983        alt->next = NULL;
 984
 985        if (pull(commit_id))
 986                rc = 1;
 987
 988        curl_slist_free_all(no_pragma_header);
 989
 990        http_cleanup();
 991
 992        return rc;
 993}