Andrew's git / gitweb.git / http-walker.c
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http-walker.con commit http*: copy string returned by sha1_to_hex (20cfb3a)
   1#include "cache.h"
   2#include "commit.h"
   3#include "pack.h"
   4#include "walker.h"
   5#include "http.h"
   6
   7#define PREV_BUF_SIZE 4096
   8#define RANGE_HEADER_SIZE 30
   9
  10struct alt_base
  11{
  12        char *base;
  13        int got_indices;
  14        struct packed_git *packs;
  15        struct alt_base *next;
  16};
  17
  18enum object_request_state {
  19        WAITING,
  20        ABORTED,
  21        ACTIVE,
  22        COMPLETE,
  23};
  24
  25struct object_request
  26{
  27        struct walker *walker;
  28        unsigned char sha1[20];
  29        struct alt_base *repo;
  30        char *url;
  31        char filename[PATH_MAX];
  32        char tmpfile[PATH_MAX];
  33        int local;
  34        enum object_request_state state;
  35        CURLcode curl_result;
  36        char errorstr[CURL_ERROR_SIZE];
  37        long http_code;
  38        unsigned char real_sha1[20];
  39        git_SHA_CTX c;
  40        z_stream stream;
  41        int zret;
  42        int rename;
  43        struct active_request_slot *slot;
  44        struct object_request *next;
  45};
  46
  47struct alternates_request {
  48        struct walker *walker;
  49        const char *base;
  50        char *url;
  51        struct strbuf *buffer;
  52        struct active_request_slot *slot;
  53        int http_specific;
  54};
  55
  56struct walker_data {
  57        const char *url;
  58        int got_alternates;
  59        struct alt_base *alt;
  60        struct curl_slist *no_pragma_header;
  61};
  62
  63static struct object_request *object_queue_head;
  64
  65static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
  66                               void *data)
  67{
  68        unsigned char expn[4096];
  69        size_t size = eltsize * nmemb;
  70        int posn = 0;
  71        struct object_request *obj_req = (struct object_request *)data;
  72        do {
  73                ssize_t retval = xwrite(obj_req->local,
  74                                        (char *) ptr + posn, size - posn);
  75                if (retval < 0)
  76                        return posn;
  77                posn += retval;
  78        } while (posn < size);
  79
  80        obj_req->stream.avail_in = size;
  81        obj_req->stream.next_in = ptr;
  82        do {
  83                obj_req->stream.next_out = expn;
  84                obj_req->stream.avail_out = sizeof(expn);
  85                obj_req->zret = git_inflate(&obj_req->stream, Z_SYNC_FLUSH);
  86                git_SHA1_Update(&obj_req->c, expn,
  87                                sizeof(expn) - obj_req->stream.avail_out);
  88        } while (obj_req->stream.avail_in && obj_req->zret == Z_OK);
  89        data_received++;
  90        return size;
  91}
  92
  93static void fetch_alternates(struct walker *walker, const char *base);
  94
  95static void process_object_response(void *callback_data);
  96
  97static void start_object_request(struct walker *walker,
  98                                 struct object_request *obj_req)
  99{
 100        char *hex = sha1_to_hex(obj_req->sha1);
 101        char prevfile[PATH_MAX];
 102        char *url;
 103        char *posn;
 104        int prevlocal;
 105        unsigned char prev_buf[PREV_BUF_SIZE];
 106        ssize_t prev_read = 0;
 107        long prev_posn = 0;
 108        char range[RANGE_HEADER_SIZE];
 109        struct curl_slist *range_header = NULL;
 110        struct active_request_slot *slot;
 111        struct walker_data *data = walker->data;
 112
 113        snprintf(prevfile, sizeof(prevfile), "%s.prev", obj_req->filename);
 114        unlink_or_warn(prevfile);
 115        rename(obj_req->tmpfile, prevfile);
 116        unlink_or_warn(obj_req->tmpfile);
 117
 118        if (obj_req->local != -1)
 119                error("fd leakage in start: %d", obj_req->local);
 120        obj_req->local = open(obj_req->tmpfile,
 121                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 122        /*
 123         * This could have failed due to the "lazy directory creation";
 124         * try to mkdir the last path component.
 125         */
 126        if (obj_req->local < 0 && errno == ENOENT) {
 127                char *dir = strrchr(obj_req->tmpfile, '/');
 128                if (dir) {
 129                        *dir = 0;
 130                        mkdir(obj_req->tmpfile, 0777);
 131                        *dir = '/';
 132                }
 133                obj_req->local = open(obj_req->tmpfile,
 134                                      O_WRONLY | O_CREAT | O_EXCL, 0666);
 135        }
 136
 137        if (obj_req->local < 0) {
 138                obj_req->state = ABORTED;
 139                error("Couldn't create temporary file %s for %s: %s",
 140                      obj_req->tmpfile, obj_req->filename, strerror(errno));
 141                return;
 142        }
 143
 144        memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 145
 146        git_inflate_init(&obj_req->stream);
 147
 148        git_SHA1_Init(&obj_req->c);
 149
 150        url = xmalloc(strlen(obj_req->repo->base) + 51);
 151        obj_req->url = xmalloc(strlen(obj_req->repo->base) + 51);
 152        strcpy(url, obj_req->repo->base);
 153        posn = url + strlen(obj_req->repo->base);
 154        strcpy(posn, "/objects/");
 155        posn += 9;
 156        memcpy(posn, hex, 2);
 157        posn += 2;
 158        *(posn++) = '/';
 159        strcpy(posn, hex + 2);
 160        strcpy(obj_req->url, url);
 161
 162        /*
 163         * If a previous temp file is present, process what was already
 164         * fetched.
 165         */
 166        prevlocal = open(prevfile, O_RDONLY);
 167        if (prevlocal != -1) {
 168                do {
 169                        prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
 170                        if (prev_read>0) {
 171                                if (fwrite_sha1_file(prev_buf,
 172                                                     1,
 173                                                     prev_read,
 174                                                     obj_req) == prev_read)
 175                                        prev_posn += prev_read;
 176                                else
 177                                        prev_read = -1;
 178                        }
 179                } while (prev_read > 0);
 180                close(prevlocal);
 181        }
 182        unlink_or_warn(prevfile);
 183
 184        /*
 185         * Reset inflate/SHA1 if there was an error reading the previous temp
 186         * file; also rewind to the beginning of the local file.
 187         */
 188        if (prev_read == -1) {
 189                memset(&obj_req->stream, 0, sizeof(obj_req->stream));
 190                git_inflate_init(&obj_req->stream);
 191                git_SHA1_Init(&obj_req->c);
 192                if (prev_posn>0) {
 193                        prev_posn = 0;
 194                        lseek(obj_req->local, 0, SEEK_SET);
 195                        ftruncate(obj_req->local, 0);
 196                }
 197        }
 198
 199        slot = get_active_slot();
 200        slot->callback_func = process_object_response;
 201        slot->callback_data = obj_req;
 202        obj_req->slot = slot;
 203
 204        curl_easy_setopt(slot->curl, CURLOPT_FILE, obj_req);
 205        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 206        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, obj_req->errorstr);
 207        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 208        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 209
 210        /*
 211         * If we have successfully processed data from a previous fetch
 212         * attempt, only fetch the data we don't already have.
 213         */
 214        if (prev_posn>0) {
 215                if (walker->get_verbosely)
 216                        fprintf(stderr,
 217                                "Resuming fetch of object %s at byte %ld\n",
 218                                hex, prev_posn);
 219                sprintf(range, "Range: bytes=%ld-", prev_posn);
 220                range_header = curl_slist_append(range_header, range);
 221                curl_easy_setopt(slot->curl,
 222                                 CURLOPT_HTTPHEADER, range_header);
 223        }
 224
 225        /* Try to get the request started, abort the request on error */
 226        obj_req->state = ACTIVE;
 227        if (!start_active_slot(slot)) {
 228                obj_req->state = ABORTED;
 229                obj_req->slot = NULL;
 230                close(obj_req->local);
 231                obj_req->local = -1;
 232                free(obj_req->url);
 233                return;
 234        }
 235}
 236
 237static void finish_object_request(struct object_request *obj_req)
 238{
 239        struct stat st;
 240
 241        close(obj_req->local);
 242        obj_req->local = -1;
 243
 244        if (obj_req->http_code == 416) {
 245                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 246        } else if (obj_req->curl_result != CURLE_OK) {
 247                if (stat(obj_req->tmpfile, &st) == 0)
 248                        if (st.st_size == 0)
 249                                unlink_or_warn(obj_req->tmpfile);
 250                return;
 251        }
 252
 253        git_inflate_end(&obj_req->stream);
 254        git_SHA1_Final(obj_req->real_sha1, &obj_req->c);
 255        if (obj_req->zret != Z_STREAM_END) {
 256                unlink_or_warn(obj_req->tmpfile);
 257                return;
 258        }
 259        if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
 260                unlink_or_warn(obj_req->tmpfile);
 261                return;
 262        }
 263        obj_req->rename =
 264                move_temp_to_file(obj_req->tmpfile, obj_req->filename);
 265
 266        if (obj_req->rename == 0)
 267                walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
 268}
 269
 270static void process_object_response(void *callback_data)
 271{
 272        struct object_request *obj_req =
 273                (struct object_request *)callback_data;
 274        struct walker *walker = obj_req->walker;
 275        struct walker_data *data = walker->data;
 276        struct alt_base *alt = data->alt;
 277
 278        obj_req->curl_result = obj_req->slot->curl_result;
 279        obj_req->http_code = obj_req->slot->http_code;
 280        obj_req->slot = NULL;
 281        obj_req->state = COMPLETE;
 282
 283        /* Use alternates if necessary */
 284        if (missing_target(obj_req)) {
 285                fetch_alternates(walker, alt->base);
 286                if (obj_req->repo->next != NULL) {
 287                        obj_req->repo =
 288                                obj_req->repo->next;
 289                        close(obj_req->local);
 290                        obj_req->local = -1;
 291                        start_object_request(walker, obj_req);
 292                        return;
 293                }
 294        }
 295
 296        finish_object_request(obj_req);
 297}
 298
 299static void release_object_request(struct object_request *obj_req)
 300{
 301        struct object_request *entry = object_queue_head;
 302
 303        if (obj_req->local != -1)
 304                error("fd leakage in release: %d", obj_req->local);
 305        if (obj_req == object_queue_head) {
 306                object_queue_head = obj_req->next;
 307        } else {
 308                while (entry->next != NULL && entry->next != obj_req)
 309                        entry = entry->next;
 310                if (entry->next == obj_req)
 311                        entry->next = entry->next->next;
 312        }
 313
 314        free(obj_req->url);
 315        free(obj_req);
 316}
 317
 318#ifdef USE_CURL_MULTI
 319static int fill_active_slot(struct walker *walker)
 320{
 321        struct object_request *obj_req;
 322
 323        for (obj_req = object_queue_head; obj_req; obj_req = obj_req->next) {
 324                if (obj_req->state == WAITING) {
 325                        if (has_sha1_file(obj_req->sha1))
 326                                obj_req->state = COMPLETE;
 327                        else {
 328                                start_object_request(walker, obj_req);
 329                                return 1;
 330                        }
 331                }
 332        }
 333        return 0;
 334}
 335#endif
 336
 337static void prefetch(struct walker *walker, unsigned char *sha1)
 338{
 339        struct object_request *newreq;
 340        struct object_request *tail;
 341        struct walker_data *data = walker->data;
 342        char *filename = sha1_file_name(sha1);
 343
 344        newreq = xmalloc(sizeof(*newreq));
 345        newreq->walker = walker;
 346        hashcpy(newreq->sha1, sha1);
 347        newreq->repo = data->alt;
 348        newreq->url = NULL;
 349        newreq->local = -1;
 350        newreq->state = WAITING;
 351        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 352        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 353                 "%s.temp", filename);
 354        newreq->slot = NULL;
 355        newreq->next = NULL;
 356
 357        if (object_queue_head == NULL) {
 358                object_queue_head = newreq;
 359        } else {
 360                tail = object_queue_head;
 361                while (tail->next != NULL)
 362                        tail = tail->next;
 363                tail->next = newreq;
 364        }
 365
 366#ifdef USE_CURL_MULTI
 367        fill_active_slots();
 368        step_active_slots();
 369#endif
 370}
 371
 372static int fetch_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 373{
 374        int ret = 0;
 375        char *hex = xstrdup(sha1_to_hex(sha1));
 376        char *filename;
 377        char *url;
 378        char tmpfile[PATH_MAX];
 379        long prev_posn = 0;
 380        char range[RANGE_HEADER_SIZE];
 381        struct curl_slist *range_header = NULL;
 382        struct walker_data *data = walker->data;
 383
 384        FILE *indexfile;
 385        struct active_request_slot *slot;
 386        struct slot_results results;
 387
 388        /* Don't use the index if the pack isn't there */
 389        url = xmalloc(strlen(repo->base) + 64);
 390        sprintf(url, "%s/objects/pack/pack-%s.pack", repo->base, hex);
 391        slot = get_active_slot();
 392        slot->results = &results;
 393        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 394        curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
 395        if (start_active_slot(slot)) {
 396                run_active_slot(slot);
 397                if (results.curl_result != CURLE_OK) {
 398                        ret = error("Unable to verify pack %s is available",
 399                                     hex);
 400                        goto cleanup_pack;
 401                }
 402        } else {
 403                ret = error("Unable to start request");
 404                goto cleanup_pack;
 405        }
 406
 407        if (has_pack_index(sha1)) {
 408                ret = 0;
 409                goto cleanup_pack;
 410        }
 411
 412        if (walker->get_verbosely)
 413                fprintf(stderr, "Getting index for pack %s\n", hex);
 414
 415        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 416
 417        filename = sha1_pack_index_name(sha1);
 418        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 419        indexfile = fopen(tmpfile, "a");
 420        if (!indexfile) {
 421                ret = error("Unable to open local file %s for pack index",
 422                            tmpfile);
 423                goto cleanup_pack;
 424        }
 425
 426        slot = get_active_slot();
 427        slot->results = &results;
 428        curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
 429        curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 430        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 431        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 432        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 433        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 434        slot->local = indexfile;
 435
 436        /*
 437         * If there is data present from a previous transfer attempt,
 438         * resume where it left off
 439         */
 440        prev_posn = ftell(indexfile);
 441        if (prev_posn>0) {
 442                if (walker->get_verbosely)
 443                        fprintf(stderr,
 444                                "Resuming fetch of index for pack %s at byte %ld\n",
 445                                hex, prev_posn);
 446                sprintf(range, "Range: bytes=%ld-", prev_posn);
 447                range_header = curl_slist_append(range_header, range);
 448                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 449        }
 450
 451        if (start_active_slot(slot)) {
 452                run_active_slot(slot);
 453                if (results.curl_result != CURLE_OK) {
 454                        ret = error("Unable to get pack index %s\n%s", url,
 455                                    curl_errorstr);
 456                        goto cleanup_index;
 457                }
 458        } else {
 459                ret = error("Unable to start request");
 460                goto cleanup_index;
 461        }
 462
 463        ret = move_temp_to_file(tmpfile, filename);
 464
 465cleanup_index:
 466        fclose(indexfile);
 467        slot->local = NULL;
 468cleanup_pack:
 469        free(url);
 470        free(hex);
 471        return ret;
 472}
 473
 474static int setup_index(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 475{
 476        struct packed_git *new_pack;
 477        if (has_pack_file(sha1))
 478                return 0; /* don't list this as something we can get */
 479
 480        if (fetch_index(walker, repo, sha1))
 481                return -1;
 482
 483        new_pack = parse_pack_index(sha1);
 484        if (!new_pack)
 485                return -1; /* parse_pack_index() already issued error message */
 486        new_pack->next = repo->packs;
 487        repo->packs = new_pack;
 488        return 0;
 489}
 490
 491static void process_alternates_response(void *callback_data)
 492{
 493        struct alternates_request *alt_req =
 494                (struct alternates_request *)callback_data;
 495        struct walker *walker = alt_req->walker;
 496        struct walker_data *cdata = walker->data;
 497        struct active_request_slot *slot = alt_req->slot;
 498        struct alt_base *tail = cdata->alt;
 499        const char *base = alt_req->base;
 500        static const char null_byte = '\0';
 501        char *data;
 502        int i = 0;
 503
 504        if (alt_req->http_specific) {
 505                if (slot->curl_result != CURLE_OK ||
 506                    !alt_req->buffer->len) {
 507
 508                        /* Try reusing the slot to get non-http alternates */
 509                        alt_req->http_specific = 0;
 510                        sprintf(alt_req->url, "%s/objects/info/alternates",
 511                                base);
 512                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 513                                         alt_req->url);
 514                        active_requests++;
 515                        slot->in_use = 1;
 516                        if (slot->finished != NULL)
 517                                (*slot->finished) = 0;
 518                        if (!start_active_slot(slot)) {
 519                                cdata->got_alternates = -1;
 520                                slot->in_use = 0;
 521                                if (slot->finished != NULL)
 522                                        (*slot->finished) = 1;
 523                        }
 524                        return;
 525                }
 526        } else if (slot->curl_result != CURLE_OK) {
 527                if (!missing_target(slot)) {
 528                        cdata->got_alternates = -1;
 529                        return;
 530                }
 531        }
 532
 533        fwrite_buffer(&null_byte, 1, 1, alt_req->buffer);
 534        alt_req->buffer->len--;
 535        data = alt_req->buffer->buf;
 536
 537        while (i < alt_req->buffer->len) {
 538                int posn = i;
 539                while (posn < alt_req->buffer->len && data[posn] != '\n')
 540                        posn++;
 541                if (data[posn] == '\n') {
 542                        int okay = 0;
 543                        int serverlen = 0;
 544                        struct alt_base *newalt;
 545                        char *target = NULL;
 546                        if (data[i] == '/') {
 547                                /*
 548                                 * This counts
 549                                 * http://git.host/pub/scm/linux.git/
 550                                 * -----------here^
 551                                 * so memcpy(dst, base, serverlen) will
 552                                 * copy up to "...git.host".
 553                                 */
 554                                const char *colon_ss = strstr(base,"://");
 555                                if (colon_ss) {
 556                                        serverlen = (strchr(colon_ss + 3, '/')
 557                                                     - base);
 558                                        okay = 1;
 559                                }
 560                        } else if (!memcmp(data + i, "../", 3)) {
 561                                /*
 562                                 * Relative URL; chop the corresponding
 563                                 * number of subpath from base (and ../
 564                                 * from data), and concatenate the result.
 565                                 *
 566                                 * The code first drops ../ from data, and
 567                                 * then drops one ../ from data and one path
 568                                 * from base.  IOW, one extra ../ is dropped
 569                                 * from data than path is dropped from base.
 570                                 *
 571                                 * This is not wrong.  The alternate in
 572                                 *     http://git.host/pub/scm/linux.git/
 573                                 * to borrow from
 574                                 *     http://git.host/pub/scm/linus.git/
 575                                 * is ../../linus.git/objects/.  You need
 576                                 * two ../../ to borrow from your direct
 577                                 * neighbour.
 578                                 */
 579                                i += 3;
 580                                serverlen = strlen(base);
 581                                while (i + 2 < posn &&
 582                                       !memcmp(data + i, "../", 3)) {
 583                                        do {
 584                                                serverlen--;
 585                                        } while (serverlen &&
 586                                                 base[serverlen - 1] != '/');
 587                                        i += 3;
 588                                }
 589                                /* If the server got removed, give up. */
 590                                okay = strchr(base, ':') - base + 3 <
 591                                       serverlen;
 592                        } else if (alt_req->http_specific) {
 593                                char *colon = strchr(data + i, ':');
 594                                char *slash = strchr(data + i, '/');
 595                                if (colon && slash && colon < data + posn &&
 596                                    slash < data + posn && colon < slash) {
 597                                        okay = 1;
 598                                }
 599                        }
 600                        /* skip "objects\n" at end */
 601                        if (okay) {
 602                                target = xmalloc(serverlen + posn - i - 6);
 603                                memcpy(target, base, serverlen);
 604                                memcpy(target + serverlen, data + i,
 605                                       posn - i - 7);
 606                                target[serverlen + posn - i - 7] = 0;
 607                                if (walker->get_verbosely)
 608                                        fprintf(stderr,
 609                                                "Also look at %s\n", target);
 610                                newalt = xmalloc(sizeof(*newalt));
 611                                newalt->next = NULL;
 612                                newalt->base = target;
 613                                newalt->got_indices = 0;
 614                                newalt->packs = NULL;
 615
 616                                while (tail->next != NULL)
 617                                        tail = tail->next;
 618                                tail->next = newalt;
 619                        }
 620                }
 621                i = posn + 1;
 622        }
 623
 624        cdata->got_alternates = 1;
 625}
 626
 627static void fetch_alternates(struct walker *walker, const char *base)
 628{
 629        struct strbuf buffer = STRBUF_INIT;
 630        char *url;
 631        struct active_request_slot *slot;
 632        struct alternates_request alt_req;
 633        struct walker_data *cdata = walker->data;
 634
 635        /*
 636         * If another request has already started fetching alternates,
 637         * wait for them to arrive and return to processing this request's
 638         * curl message
 639         */
 640#ifdef USE_CURL_MULTI
 641        while (cdata->got_alternates == 0) {
 642                step_active_slots();
 643        }
 644#endif
 645
 646        /* Nothing to do if they've already been fetched */
 647        if (cdata->got_alternates == 1)
 648                return;
 649
 650        /* Start the fetch */
 651        cdata->got_alternates = 0;
 652
 653        if (walker->get_verbosely)
 654                fprintf(stderr, "Getting alternates list for %s\n", base);
 655
 656        url = xmalloc(strlen(base) + 31);
 657        sprintf(url, "%s/objects/info/http-alternates", base);
 658
 659        /*
 660         * Use a callback to process the result, since another request
 661         * may fail and need to have alternates loaded before continuing
 662         */
 663        slot = get_active_slot();
 664        slot->callback_func = process_alternates_response;
 665        alt_req.walker = walker;
 666        slot->callback_data = &alt_req;
 667
 668        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 669        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 670        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 671
 672        alt_req.base = base;
 673        alt_req.url = url;
 674        alt_req.buffer = &buffer;
 675        alt_req.http_specific = 1;
 676        alt_req.slot = slot;
 677
 678        if (start_active_slot(slot))
 679                run_active_slot(slot);
 680        else
 681                cdata->got_alternates = -1;
 682
 683        strbuf_release(&buffer);
 684        free(url);
 685}
 686
 687static int fetch_indices(struct walker *walker, struct alt_base *repo)
 688{
 689        unsigned char sha1[20];
 690        char *url;
 691        struct strbuf buffer = STRBUF_INIT;
 692        char *data;
 693        int i = 0;
 694        int ret = 0;
 695
 696        struct active_request_slot *slot;
 697        struct slot_results results;
 698
 699        if (repo->got_indices)
 700                return 0;
 701
 702        if (walker->get_verbosely)
 703                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 704
 705        url = xmalloc(strlen(repo->base) + 21);
 706        sprintf(url, "%s/objects/info/packs", repo->base);
 707
 708        slot = get_active_slot();
 709        slot->results = &results;
 710        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 711        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 712        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 713        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 714        if (start_active_slot(slot)) {
 715                run_active_slot(slot);
 716                if (results.curl_result != CURLE_OK) {
 717                        if (missing_target(&results)) {
 718                                repo->got_indices = 1;
 719                                goto cleanup;
 720                        } else {
 721                                repo->got_indices = 0;
 722                                ret = error("%s", curl_errorstr);
 723                                goto cleanup;
 724                        }
 725                }
 726        } else {
 727                repo->got_indices = 0;
 728                ret = error("Unable to start request");
 729                goto cleanup;
 730        }
 731
 732        data = buffer.buf;
 733        while (i < buffer.len) {
 734                switch (data[i]) {
 735                case 'P':
 736                        i++;
 737                        if (i + 52 <= buffer.len &&
 738                            !prefixcmp(data + i, " pack-") &&
 739                            !prefixcmp(data + i + 46, ".pack\n")) {
 740                                get_sha1_hex(data + i + 6, sha1);
 741                                setup_index(walker, repo, sha1);
 742                                i += 51;
 743                                break;
 744                        }
 745                default:
 746                        while (i < buffer.len && data[i] != '\n')
 747                                i++;
 748                }
 749                i++;
 750        }
 751
 752        repo->got_indices = 1;
 753cleanup:
 754        strbuf_release(&buffer);
 755        free(url);
 756        return ret;
 757}
 758
 759static int fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 760{
 761        char *url;
 762        struct packed_git *target;
 763        struct packed_git **lst;
 764        FILE *packfile;
 765        char *filename;
 766        char tmpfile[PATH_MAX];
 767        int ret;
 768        long prev_posn = 0;
 769        char range[RANGE_HEADER_SIZE];
 770        struct curl_slist *range_header = NULL;
 771        struct walker_data *data = walker->data;
 772
 773        struct active_request_slot *slot;
 774        struct slot_results results;
 775
 776        if (fetch_indices(walker, repo))
 777                return -1;
 778        target = find_sha1_pack(sha1, repo->packs);
 779        if (!target)
 780                return -1;
 781
 782        if (walker->get_verbosely) {
 783                fprintf(stderr, "Getting pack %s\n",
 784                        sha1_to_hex(target->sha1));
 785                fprintf(stderr, " which contains %s\n",
 786                        sha1_to_hex(sha1));
 787        }
 788
 789        url = xmalloc(strlen(repo->base) + 65);
 790        sprintf(url, "%s/objects/pack/pack-%s.pack",
 791                repo->base, sha1_to_hex(target->sha1));
 792
 793        filename = sha1_pack_name(target->sha1);
 794        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 795        packfile = fopen(tmpfile, "a");
 796        if (!packfile)
 797                return error("Unable to open local file %s for pack",
 798                             tmpfile);
 799
 800        slot = get_active_slot();
 801        slot->results = &results;
 802        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 803        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 804        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 805        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, data->no_pragma_header);
 806        slot->local = packfile;
 807
 808        /*
 809         * If there is data present from a previous transfer attempt,
 810         * resume where it left off
 811         */
 812        prev_posn = ftell(packfile);
 813        if (prev_posn>0) {
 814                if (walker->get_verbosely)
 815                        fprintf(stderr,
 816                                "Resuming fetch of pack %s at byte %ld\n",
 817                                sha1_to_hex(target->sha1), prev_posn);
 818                sprintf(range, "Range: bytes=%ld-", prev_posn);
 819                range_header = curl_slist_append(range_header, range);
 820                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 821        }
 822
 823        if (start_active_slot(slot)) {
 824                run_active_slot(slot);
 825                if (results.curl_result != CURLE_OK) {
 826                        fclose(packfile);
 827                        slot->local = NULL;
 828                        return error("Unable to get pack file %s\n%s", url,
 829                                     curl_errorstr);
 830                }
 831        } else {
 832                fclose(packfile);
 833                slot->local = NULL;
 834                return error("Unable to start request");
 835        }
 836
 837        target->pack_size = ftell(packfile);
 838        fclose(packfile);
 839        slot->local = NULL;
 840
 841        ret = move_temp_to_file(tmpfile, filename);
 842        if (ret)
 843                return ret;
 844
 845        lst = &repo->packs;
 846        while (*lst != target)
 847                lst = &((*lst)->next);
 848        *lst = (*lst)->next;
 849
 850        if (verify_pack(target))
 851                return -1;
 852        install_packed_git(target);
 853
 854        return 0;
 855}
 856
 857static void abort_object_request(struct object_request *obj_req)
 858{
 859        if (obj_req->local >= 0) {
 860                close(obj_req->local);
 861                obj_req->local = -1;
 862        }
 863        unlink_or_warn(obj_req->tmpfile);
 864        if (obj_req->slot) {
 865                release_active_slot(obj_req->slot);
 866                obj_req->slot = NULL;
 867        }
 868        release_object_request(obj_req);
 869}
 870
 871static int fetch_object(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 872{
 873        char *hex = sha1_to_hex(sha1);
 874        int ret = 0;
 875        struct object_request *obj_req = object_queue_head;
 876
 877        while (obj_req != NULL && hashcmp(obj_req->sha1, sha1))
 878                obj_req = obj_req->next;
 879        if (obj_req == NULL)
 880                return error("Couldn't find request for %s in the queue", hex);
 881
 882        if (has_sha1_file(obj_req->sha1)) {
 883                abort_object_request(obj_req);
 884                return 0;
 885        }
 886
 887#ifdef USE_CURL_MULTI
 888        while (obj_req->state == WAITING)
 889                step_active_slots();
 890#else
 891        start_object_request(walker, obj_req);
 892#endif
 893
 894        while (obj_req->state == ACTIVE)
 895                run_active_slot(obj_req->slot);
 896
 897        if (obj_req->local != -1) {
 898                close(obj_req->local);
 899                obj_req->local = -1;
 900        }
 901
 902        if (obj_req->state == ABORTED) {
 903                ret = error("Request for %s aborted", hex);
 904        } else if (obj_req->curl_result != CURLE_OK &&
 905                   obj_req->http_code != 416) {
 906                if (missing_target(obj_req))
 907                        ret = -1; /* Be silent, it is probably in a pack. */
 908                else
 909                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 910                                    obj_req->errorstr, obj_req->curl_result,
 911                                    obj_req->http_code, hex);
 912        } else if (obj_req->zret != Z_STREAM_END) {
 913                walker->corrupt_object_found++;
 914                ret = error("File %s (%s) corrupt", hex, obj_req->url);
 915        } else if (hashcmp(obj_req->sha1, obj_req->real_sha1)) {
 916                ret = error("File %s has bad hash", hex);
 917        } else if (obj_req->rename < 0) {
 918                ret = error("unable to write sha1 filename %s",
 919                            obj_req->filename);
 920        }
 921
 922        release_object_request(obj_req);
 923        return ret;
 924}
 925
 926static int fetch(struct walker *walker, unsigned char *sha1)
 927{
 928        struct walker_data *data = walker->data;
 929        struct alt_base *altbase = data->alt;
 930
 931        if (!fetch_object(walker, altbase, sha1))
 932                return 0;
 933        while (altbase) {
 934                if (!fetch_pack(walker, altbase, sha1))
 935                        return 0;
 936                fetch_alternates(walker, data->alt->base);
 937                altbase = altbase->next;
 938        }
 939        return error("Unable to find %s under %s", sha1_to_hex(sha1),
 940                     data->alt->base);
 941}
 942
 943static int fetch_ref(struct walker *walker, struct ref *ref)
 944{
 945        struct walker_data *data = walker->data;
 946        return http_fetch_ref(data->alt->base, ref);
 947}
 948
 949static void cleanup(struct walker *walker)
 950{
 951        struct walker_data *data = walker->data;
 952        http_cleanup();
 953
 954        curl_slist_free_all(data->no_pragma_header);
 955}
 956
 957struct walker *get_http_walker(const char *url, struct remote *remote)
 958{
 959        char *s;
 960        struct walker_data *data = xmalloc(sizeof(struct walker_data));
 961        struct walker *walker = xmalloc(sizeof(struct walker));
 962
 963        http_init(remote);
 964
 965        data->no_pragma_header = curl_slist_append(NULL, "Pragma:");
 966
 967        data->alt = xmalloc(sizeof(*data->alt));
 968        data->alt->base = xmalloc(strlen(url) + 1);
 969        strcpy(data->alt->base, url);
 970        for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 971                *s = 0;
 972
 973        data->alt->got_indices = 0;
 974        data->alt->packs = NULL;
 975        data->alt->next = NULL;
 976        data->got_alternates = -1;
 977
 978        walker->corrupt_object_found = 0;
 979        walker->fetch = fetch;
 980        walker->fetch_ref = fetch_ref;
 981        walker->prefetch = prefetch;
 982        walker->cleanup = cleanup;
 983        walker->data = data;
 984
 985#ifdef USE_CURL_MULTI
 986        add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 987#endif
 988
 989        return walker;
 990}