Andrew's git / gitweb.git / http-fetch.c
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http-fetch.con commit cvs-migration documentation update (b8bc67c)
   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}
 225
 226static void finish_object_request(struct object_request *obj_req)
 227{
 228        struct stat st;
 229
 230        fchmod(obj_req->local, 0444);
 231        close(obj_req->local); obj_req->local = -1;
 232
 233        if (obj_req->http_code == 416) {
 234                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 235        } else if (obj_req->curl_result != CURLE_OK) {
 236                if (stat(obj_req->tmpfile, &st) == 0)
 237                        if (st.st_size == 0)
 238                                unlink(obj_req->tmpfile);
 239                return;
 240        }
 241
 242        inflateEnd(&obj_req->stream);
 243        SHA1_Final(obj_req->real_sha1, &obj_req->c);
 244        if (obj_req->zret != Z_STREAM_END) {
 245                unlink(obj_req->tmpfile);
 246                return;
 247        }
 248        if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 249                unlink(obj_req->tmpfile);
 250                return;
 251        }
 252        obj_req->rename =
 253                move_temp_to_file(obj_req->tmpfile, obj_req->filename);
 254
 255        if (obj_req->rename == 0)
 256                pull_say("got %s\n", sha1_to_hex(obj_req->sha1));
 257}
 258
 259static void process_object_response(void *callback_data)
 260{
 261        struct object_request *obj_req =
 262                (struct object_request *)callback_data;
 263
 264        obj_req->curl_result = obj_req->slot->curl_result;
 265        obj_req->http_code = obj_req->slot->http_code;
 266        obj_req->slot = NULL;
 267        obj_req->state = COMPLETE;
 268
 269        /* Use alternates if necessary */
 270        if (obj_req->http_code == 404 ||
 271            obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 272                fetch_alternates(alt->base);
 273                if (obj_req->repo->next != NULL) {
 274                        obj_req->repo =
 275                                obj_req->repo->next;
 276                        close(obj_req->local);
 277                        obj_req->local = -1;
 278                        start_object_request(obj_req);
 279                        return;
 280                }
 281        }
 282
 283        finish_object_request(obj_req);
 284}
 285
 286static void release_object_request(struct object_request *obj_req)
 287{
 288        struct object_request *entry = object_queue_head;
 289
 290        if (obj_req->local != -1)
 291                error("fd leakage in release: %d", obj_req->local);
 292        if (obj_req == object_queue_head) {
 293                object_queue_head = obj_req->next;
 294        } else {
 295                while (entry->next != NULL && entry->next != obj_req)
 296                        entry = entry->next;
 297                if (entry->next == obj_req)
 298                        entry->next = entry->next->next;
 299        }
 300
 301        free(obj_req->url);
 302        free(obj_req);
 303}
 304
 305#ifdef USE_CURL_MULTI
 306void fill_active_slots(void)
 307{
 308        struct object_request *obj_req = object_queue_head;
 309        struct active_request_slot *slot = active_queue_head;
 310        int num_transfers;
 311
 312        while (active_requests < max_requests && obj_req != NULL) {
 313                if (obj_req->state == WAITING) {
 314                        if (has_sha1_file(obj_req->sha1))
 315                                release_object_request(obj_req);
 316                        else
 317                                start_object_request(obj_req);
 318                        curl_multi_perform(curlm, &num_transfers);
 319                }
 320                obj_req = obj_req->next;
 321        }
 322
 323        while (slot != NULL) {
 324                if (!slot->in_use && slot->curl != NULL) {
 325                        curl_easy_cleanup(slot->curl);
 326                        slot->curl = NULL;
 327                }
 328                slot = slot->next;
 329        }                               
 330}
 331#endif
 332
 333void prefetch(unsigned char *sha1)
 334{
 335        struct object_request *newreq;
 336        struct object_request *tail;
 337        char *filename = sha1_file_name(sha1);
 338
 339        newreq = xmalloc(sizeof(*newreq));
 340        memcpy(newreq->sha1, sha1, 20);
 341        newreq->repo = alt;
 342        newreq->url = NULL;
 343        newreq->local = -1;
 344        newreq->state = WAITING;
 345        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 346        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 347                 "%s.temp", filename);
 348        newreq->next = NULL;
 349
 350        if (object_queue_head == NULL) {
 351                object_queue_head = newreq;
 352        } else {
 353                tail = object_queue_head;
 354                while (tail->next != NULL) {
 355                        tail = tail->next;
 356                }
 357                tail->next = newreq;
 358        }
 359
 360#ifdef USE_CURL_MULTI
 361        fill_active_slots();
 362        step_active_slots();
 363#endif
 364}
 365
 366static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 367{
 368        char *hex = sha1_to_hex(sha1);
 369        char *filename;
 370        char *url;
 371        char tmpfile[PATH_MAX];
 372        long prev_posn = 0;
 373        char range[RANGE_HEADER_SIZE];
 374        struct curl_slist *range_header = NULL;
 375
 376        FILE *indexfile;
 377        struct active_request_slot *slot;
 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        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 397        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 398        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 399        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 400        slot->local = indexfile;
 401
 402        /* If there is data present from a previous transfer attempt,
 403           resume where it left off */
 404        prev_posn = ftell(indexfile);
 405        if (prev_posn>0) {
 406                if (get_verbosely)
 407                        fprintf(stderr,
 408                                "Resuming fetch of index for pack %s at byte %ld\n",
 409                                hex, prev_posn);
 410                sprintf(range, "Range: bytes=%ld-", prev_posn);
 411                range_header = curl_slist_append(range_header, range);
 412                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 413        }
 414
 415        if (start_active_slot(slot)) {
 416                run_active_slot(slot);
 417                if (slot->curl_result != CURLE_OK) {
 418                        fclose(indexfile);
 419                        return error("Unable to get pack index %s\n%s", url,
 420                                     curl_errorstr);
 421                }
 422        } else {
 423                fclose(indexfile);
 424                return error("Unable to start request");
 425        }
 426
 427        fclose(indexfile);
 428
 429        return move_temp_to_file(tmpfile, filename);
 430}
 431
 432static int setup_index(struct alt_base *repo, unsigned char *sha1)
 433{
 434        struct packed_git *new_pack;
 435        if (has_pack_file(sha1))
 436                return 0; // don't list this as something we can get
 437
 438        if (fetch_index(repo, sha1))
 439                return -1;
 440
 441        new_pack = parse_pack_index(sha1);
 442        new_pack->next = repo->packs;
 443        repo->packs = new_pack;
 444        return 0;
 445}
 446
 447static void process_alternates_response(void *callback_data)
 448{
 449        struct alternates_request *alt_req =
 450                (struct alternates_request *)callback_data;
 451        struct active_request_slot *slot = alt_req->slot;
 452        struct alt_base *tail = alt;
 453        char *base = alt_req->base;
 454        static const char null_byte = '\0';
 455        char *data;
 456        int i = 0;
 457
 458        if (alt_req->http_specific) {
 459                if (slot->curl_result != CURLE_OK ||
 460                    !alt_req->buffer->posn) {
 461
 462                        /* Try reusing the slot to get non-http alternates */
 463                        alt_req->http_specific = 0;
 464                        sprintf(alt_req->url, "%s/objects/info/alternates",
 465                                base);
 466                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 467                                         alt_req->url);
 468                        active_requests++;
 469                        slot->in_use = 1;
 470                        if (start_active_slot(slot)) {
 471                                return;
 472                        } else {
 473                                got_alternates = -1;
 474                                slot->in_use = 0;
 475                                return;
 476                        }
 477                }
 478        } else if (slot->curl_result != CURLE_OK) {
 479                if (slot->http_code != 404 &&
 480                    slot->curl_result != CURLE_FILE_COULDNT_READ_FILE) {
 481                        got_alternates = -1;
 482                        return;
 483                }
 484        }
 485
 486        fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 487        alt_req->buffer->posn--;
 488        data = alt_req->buffer->buffer;
 489
 490        while (i < alt_req->buffer->posn) {
 491                int posn = i;
 492                while (posn < alt_req->buffer->posn && data[posn] != '\n')
 493                        posn++;
 494                if (data[posn] == '\n') {
 495                        int okay = 0;
 496                        int serverlen = 0;
 497                        struct alt_base *newalt;
 498                        char *target = NULL;
 499                        if (data[i] == '/') {
 500                                serverlen = strchr(base + 8, '/') - base;
 501                                okay = 1;
 502                        } else if (!memcmp(data + i, "../", 3)) {
 503                                i += 3;
 504                                serverlen = strlen(base);
 505                                while (i + 2 < posn && 
 506                                       !memcmp(data + i, "../", 3)) {
 507                                        do {
 508                                                serverlen--;
 509                                        } while (serverlen &&
 510                                                 base[serverlen - 1] != '/');
 511                                        i += 3;
 512                                }
 513                                // If the server got removed, give up.
 514                                okay = strchr(base, ':') - base + 3 < 
 515                                        serverlen;
 516                        } else if (alt_req->http_specific) {
 517                                char *colon = strchr(data + i, ':');
 518                                char *slash = strchr(data + i, '/');
 519                                if (colon && slash && colon < data + posn &&
 520                                    slash < data + posn && colon < slash) {
 521                                        okay = 1;
 522                                }
 523                        }
 524                        // skip 'objects' at end
 525                        if (okay) {
 526                                target = xmalloc(serverlen + posn - i - 6);
 527                                strncpy(target, base, serverlen);
 528                                strncpy(target + serverlen, data + i,
 529                                        posn - i - 7);
 530                                target[serverlen + posn - i - 7] = '\0';
 531                                if (get_verbosely)
 532                                        fprintf(stderr, 
 533                                                "Also look at %s\n", target);
 534                                newalt = xmalloc(sizeof(*newalt));
 535                                newalt->next = NULL;
 536                                newalt->base = target;
 537                                newalt->got_indices = 0;
 538                                newalt->packs = NULL;
 539                                while (tail->next != NULL)
 540                                        tail = tail->next;
 541                                tail->next = newalt;
 542                        }
 543                }
 544                i = posn + 1;
 545        }
 546
 547        got_alternates = 1;
 548}
 549
 550static void fetch_alternates(char *base)
 551{
 552        struct buffer buffer;
 553        char *url;
 554        char *data;
 555        struct active_request_slot *slot;
 556        static struct alternates_request alt_req;
 557
 558        /* If another request has already started fetching alternates,
 559           wait for them to arrive and return to processing this request's
 560           curl message */
 561#ifdef USE_CURL_MULTI
 562        while (got_alternates == 0) {
 563                step_active_slots();
 564        }
 565#endif
 566
 567        /* Nothing to do if they've already been fetched */
 568        if (got_alternates == 1)
 569                return;
 570
 571        /* Start the fetch */
 572        got_alternates = 0;
 573
 574        data = xmalloc(4096);
 575        buffer.size = 4096;
 576        buffer.posn = 0;
 577        buffer.buffer = data;
 578
 579        if (get_verbosely)
 580                fprintf(stderr, "Getting alternates list for %s\n", base);
 581        
 582        url = xmalloc(strlen(base) + 31);
 583        sprintf(url, "%s/objects/info/http-alternates", base);
 584
 585        /* Use a callback to process the result, since another request
 586           may fail and need to have alternates loaded before continuing */
 587        slot = get_active_slot();
 588        slot->callback_func = process_alternates_response;
 589        slot->callback_data = &alt_req;
 590
 591        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 592        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 593        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 594
 595        alt_req.base = base;
 596        alt_req.url = url;
 597        alt_req.buffer = &buffer;
 598        alt_req.http_specific = 1;
 599        alt_req.slot = slot;
 600
 601        if (start_active_slot(slot))
 602                run_active_slot(slot);
 603        else
 604                got_alternates = -1;
 605
 606        free(data);
 607        free(url);
 608}
 609
 610static int fetch_indices(struct alt_base *repo)
 611{
 612        unsigned char sha1[20];
 613        char *url;
 614        struct buffer buffer;
 615        char *data;
 616        int i = 0;
 617
 618        struct active_request_slot *slot;
 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        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 636        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 637        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 638        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 639        if (start_active_slot(slot)) {
 640                run_active_slot(slot);
 641                if (slot->curl_result != CURLE_OK) {
 642                        if (slot->http_code == 404 ||
 643                            slot->curl_result == CURLE_FILE_COULDNT_READ_FILE) {
 644                                repo->got_indices = 1;
 645                                free(buffer.buffer);
 646                                return 0;
 647                        } else {
 648                                repo->got_indices = 0;
 649                                free(buffer.buffer);
 650                                return error("%s", curl_errorstr);
 651                        }
 652                }
 653        } else {
 654                repo->got_indices = 0;
 655                free(buffer.buffer);
 656                return error("Unable to start request");
 657        }
 658
 659        data = buffer.buffer;
 660        while (i < buffer.posn) {
 661                switch (data[i]) {
 662                case 'P':
 663                        i++;
 664                        if (i + 52 <= buffer.posn &&
 665                            !strncmp(data + i, " pack-", 6) &&
 666                            !strncmp(data + i + 46, ".pack\n", 6)) {
 667                                get_sha1_hex(data + i + 6, sha1);
 668                                setup_index(repo, sha1);
 669                                i += 51;
 670                                break;
 671                        }
 672                default:
 673                        while (i < buffer.posn && data[i] != '\n')
 674                                i++;
 675                }
 676                i++;
 677        }
 678
 679        free(buffer.buffer);
 680        repo->got_indices = 1;
 681        return 0;
 682}
 683
 684static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 685{
 686        char *url;
 687        struct packed_git *target;
 688        struct packed_git **lst;
 689        FILE *packfile;
 690        char *filename;
 691        char tmpfile[PATH_MAX];
 692        int ret;
 693        long prev_posn = 0;
 694        char range[RANGE_HEADER_SIZE];
 695        struct curl_slist *range_header = NULL;
 696
 697        struct active_request_slot *slot;
 698
 699        if (fetch_indices(repo))
 700                return -1;
 701        target = find_sha1_pack(sha1, repo->packs);
 702        if (!target)
 703                return -1;
 704
 705        if (get_verbosely) {
 706                fprintf(stderr, "Getting pack %s\n",
 707                        sha1_to_hex(target->sha1));
 708                fprintf(stderr, " which contains %s\n",
 709                        sha1_to_hex(sha1));
 710        }
 711
 712        url = xmalloc(strlen(repo->base) + 65);
 713        sprintf(url, "%s/objects/pack/pack-%s.pack",
 714                repo->base, sha1_to_hex(target->sha1));
 715
 716        filename = sha1_pack_name(target->sha1);
 717        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 718        packfile = fopen(tmpfile, "a");
 719        if (!packfile)
 720                return error("Unable to open local file %s for pack",
 721                             filename);
 722
 723        slot = get_active_slot();
 724        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 725        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 726        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 727        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 728        slot->local = packfile;
 729
 730        /* If there is data present from a previous transfer attempt,
 731           resume where it left off */
 732        prev_posn = ftell(packfile);
 733        if (prev_posn>0) {
 734                if (get_verbosely)
 735                        fprintf(stderr,
 736                                "Resuming fetch of pack %s at byte %ld\n",
 737                                sha1_to_hex(target->sha1), prev_posn);
 738                sprintf(range, "Range: bytes=%ld-", prev_posn);
 739                range_header = curl_slist_append(range_header, range);
 740                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 741        }
 742
 743        if (start_active_slot(slot)) {
 744                run_active_slot(slot);
 745                if (slot->curl_result != CURLE_OK) {
 746                        fclose(packfile);
 747                        return error("Unable to get pack file %s\n%s", url,
 748                                     curl_errorstr);
 749                }
 750        } else {
 751                fclose(packfile);
 752                return error("Unable to start request");
 753        }
 754
 755        fclose(packfile);
 756
 757        ret = move_temp_to_file(tmpfile, filename);
 758        if (ret)
 759                return ret;
 760
 761        lst = &repo->packs;
 762        while (*lst != target)
 763                lst = &((*lst)->next);
 764        *lst = (*lst)->next;
 765
 766        if (verify_pack(target, 0))
 767                return -1;
 768        install_packed_git(target);
 769
 770        return 0;
 771}
 772
 773static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 774{
 775        char *hex = sha1_to_hex(sha1);
 776        int ret = 0;
 777        struct object_request *obj_req = object_queue_head;
 778
 779        while (obj_req != NULL && memcmp(obj_req->sha1, sha1, 20))
 780                obj_req = obj_req->next;
 781        if (obj_req == NULL)
 782                return error("Couldn't find request for %s in the queue", hex);
 783
 784        if (has_sha1_file(obj_req->sha1)) {
 785                release_object_request(obj_req);
 786                return 0;
 787        }
 788
 789#ifdef USE_CURL_MULTI
 790        while (obj_req->state == WAITING) {
 791                step_active_slots();
 792        }
 793#else
 794        start_object_request(obj_req);
 795#endif
 796
 797        while (obj_req->state == ACTIVE) {
 798                run_active_slot(obj_req->slot);
 799        }
 800        if (obj_req->local != -1) {
 801                close(obj_req->local); obj_req->local = -1;
 802        }
 803
 804        if (obj_req->state == ABORTED) {
 805                ret = error("Request for %s aborted", hex);
 806        } else if (obj_req->curl_result != CURLE_OK &&
 807                   obj_req->http_code != 416) {
 808                if (obj_req->http_code == 404 ||
 809                    obj_req->curl_result == CURLE_FILE_COULDNT_READ_FILE)
 810                        ret = -1; /* Be silent, it is probably in a pack. */
 811                else
 812                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 813                                    obj_req->errorstr, obj_req->curl_result,
 814                                    obj_req->http_code, hex);
 815        } else if (obj_req->zret != Z_STREAM_END) {
 816                ret = error("File %s (%s) corrupt\n", hex, obj_req->url);
 817        } else if (memcmp(obj_req->sha1, obj_req->real_sha1, 20)) {
 818                ret = error("File %s has bad hash\n", hex);
 819        } else if (obj_req->rename < 0) {
 820                ret = error("unable to write sha1 filename %s: %s",
 821                            obj_req->filename,
 822                            strerror(obj_req->rename));
 823        }
 824
 825        release_object_request(obj_req);
 826        return ret;
 827}
 828
 829int fetch(unsigned char *sha1)
 830{
 831        struct alt_base *altbase = alt;
 832
 833        if (!fetch_object(altbase, sha1))
 834                return 0;
 835        while (altbase) {
 836                if (!fetch_pack(altbase, sha1))
 837                        return 0;
 838                fetch_alternates(alt->base);
 839                altbase = altbase->next;
 840        }
 841        return error("Unable to find %s under %s\n", sha1_to_hex(sha1), 
 842                     alt->base);
 843}
 844
 845static inline int needs_quote(int ch)
 846{
 847        switch (ch) {
 848        case '/': case '-': case '.':
 849        case 'A'...'Z': case 'a'...'z': case '0'...'9':
 850                return 0;
 851        default:
 852                return 1;
 853        }
 854}
 855
 856static inline int hex(int v)
 857{
 858        if (v < 10) return '0' + v;
 859        else return 'A' + v - 10;
 860}
 861
 862static char *quote_ref_url(const char *base, const char *ref)
 863{
 864        const char *cp;
 865        char *dp, *qref;
 866        int len, baselen, ch;
 867
 868        baselen = strlen(base);
 869        len = baselen + 6; /* "refs/" + NUL */
 870        for (cp = ref; (ch = *cp) != 0; cp++, len++)
 871                if (needs_quote(ch))
 872                        len += 2; /* extra two hex plus replacement % */
 873        qref = xmalloc(len);
 874        memcpy(qref, base, baselen);
 875        memcpy(qref + baselen, "refs/", 5);
 876        for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
 877                if (needs_quote(ch)) {
 878                        *dp++ = '%';
 879                        *dp++ = hex((ch >> 4) & 0xF);
 880                        *dp++ = hex(ch & 0xF);
 881                }
 882                else
 883                        *dp++ = ch;
 884        }
 885        *dp = 0;
 886
 887        return qref;
 888}
 889
 890int fetch_ref(char *ref, unsigned char *sha1)
 891{
 892        char *url;
 893        char hex[42];
 894        struct buffer buffer;
 895        char *base = alt->base;
 896        struct active_request_slot *slot;
 897        buffer.size = 41;
 898        buffer.posn = 0;
 899        buffer.buffer = hex;
 900        hex[41] = '\0';
 901        
 902        url = quote_ref_url(base, ref);
 903        slot = get_active_slot();
 904        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 905        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 906        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 907        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 908        if (start_active_slot(slot)) {
 909                run_active_slot(slot);
 910                if (slot->curl_result != CURLE_OK)
 911                        return error("Couldn't get %s for %s\n%s",
 912                                     url, ref, curl_errorstr);
 913        } else {
 914                return error("Unable to start request");
 915        }
 916
 917        hex[40] = '\0';
 918        get_sha1_hex(hex, sha1);
 919        return 0;
 920}
 921
 922int main(int argc, char **argv)
 923{
 924        char *commit_id;
 925        char *url;
 926        int arg = 1;
 927        int rc = 0;
 928
 929        setup_git_directory();
 930
 931        while (arg < argc && argv[arg][0] == '-') {
 932                if (argv[arg][1] == 't') {
 933                        get_tree = 1;
 934                } else if (argv[arg][1] == 'c') {
 935                        get_history = 1;
 936                } else if (argv[arg][1] == 'a') {
 937                        get_all = 1;
 938                        get_tree = 1;
 939                        get_history = 1;
 940                } else if (argv[arg][1] == 'v') {
 941                        get_verbosely = 1;
 942                } else if (argv[arg][1] == 'w') {
 943                        write_ref = argv[arg + 1];
 944                        arg++;
 945                } else if (!strcmp(argv[arg], "--recover")) {
 946                        get_recover = 1;
 947                }
 948                arg++;
 949        }
 950        if (argc < arg + 2) {
 951                usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
 952                return 1;
 953        }
 954        commit_id = argv[arg];
 955        url = argv[arg + 1];
 956
 957        http_init();
 958
 959        no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 960
 961        alt = xmalloc(sizeof(*alt));
 962        alt->base = url;
 963        alt->got_indices = 0;
 964        alt->packs = NULL;
 965        alt->next = NULL;
 966
 967        if (pull(commit_id))
 968                rc = 1;
 969
 970        curl_slist_free_all(no_pragma_header);
 971
 972        http_cleanup();
 973
 974        return rc;
 975}