Andrew's git / gitweb.git / http-walker.c
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http-walker.con commit Merge branch 'mh/packed-ref-store-prep' into maint (6b89503)
   1#include "cache.h"
   2#include "commit.h"
   3#include "walker.h"
   4#include "http.h"
   5#include "list.h"
   6#include "transport.h"
   7
   8struct alt_base {
   9        char *base;
  10        int got_indices;
  11        struct packed_git *packs;
  12        struct alt_base *next;
  13};
  14
  15enum object_request_state {
  16        WAITING,
  17        ABORTED,
  18        ACTIVE,
  19        COMPLETE
  20};
  21
  22struct object_request {
  23        struct walker *walker;
  24        unsigned char sha1[20];
  25        struct alt_base *repo;
  26        enum object_request_state state;
  27        struct http_object_request *req;
  28        struct list_head node;
  29};
  30
  31struct alternates_request {
  32        struct walker *walker;
  33        const char *base;
  34        struct strbuf *url;
  35        struct strbuf *buffer;
  36        struct active_request_slot *slot;
  37        int http_specific;
  38};
  39
  40struct walker_data {
  41        const char *url;
  42        int got_alternates;
  43        struct alt_base *alt;
  44};
  45
  46static LIST_HEAD(object_queue_head);
  47
  48static void fetch_alternates(struct walker *walker, const char *base);
  49
  50static void process_object_response(void *callback_data);
  51
  52static void start_object_request(struct walker *walker,
  53                                 struct object_request *obj_req)
  54{
  55        struct active_request_slot *slot;
  56        struct http_object_request *req;
  57
  58        req = new_http_object_request(obj_req->repo->base, obj_req->sha1);
  59        if (req == NULL) {
  60                obj_req->state = ABORTED;
  61                return;
  62        }
  63        obj_req->req = req;
  64
  65        slot = req->slot;
  66        slot->callback_func = process_object_response;
  67        slot->callback_data = obj_req;
  68
  69        /* Try to get the request started, abort the request on error */
  70        obj_req->state = ACTIVE;
  71        if (!start_active_slot(slot)) {
  72                obj_req->state = ABORTED;
  73                release_http_object_request(req);
  74                return;
  75        }
  76}
  77
  78static void finish_object_request(struct object_request *obj_req)
  79{
  80        if (finish_http_object_request(obj_req->req))
  81                return;
  82
  83        if (obj_req->req->rename == 0)
  84                walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
  85}
  86
  87static void process_object_response(void *callback_data)
  88{
  89        struct object_request *obj_req =
  90                (struct object_request *)callback_data;
  91        struct walker *walker = obj_req->walker;
  92        struct walker_data *data = walker->data;
  93        struct alt_base *alt = data->alt;
  94
  95        process_http_object_request(obj_req->req);
  96        obj_req->state = COMPLETE;
  97
  98        /* Use alternates if necessary */
  99        if (missing_target(obj_req->req)) {
 100                fetch_alternates(walker, alt->base);
 101                if (obj_req->repo->next != NULL) {
 102                        obj_req->repo =
 103                                obj_req->repo->next;
 104                        release_http_object_request(obj_req->req);
 105                        start_object_request(walker, obj_req);
 106                        return;
 107                }
 108        }
 109
 110        finish_object_request(obj_req);
 111}
 112
 113static void release_object_request(struct object_request *obj_req)
 114{
 115        if (obj_req->req !=NULL && obj_req->req->localfile != -1)
 116                error("fd leakage in release: %d", obj_req->req->localfile);
 117
 118        list_del(&obj_req->node);
 119        free(obj_req);
 120}
 121
 122#ifdef USE_CURL_MULTI
 123static int fill_active_slot(struct walker *walker)
 124{
 125        struct object_request *obj_req;
 126        struct list_head *pos, *tmp, *head = &object_queue_head;
 127
 128        list_for_each_safe(pos, tmp, head) {
 129                obj_req = list_entry(pos, struct object_request, node);
 130                if (obj_req->state == WAITING) {
 131                        if (has_sha1_file(obj_req->sha1))
 132                                obj_req->state = COMPLETE;
 133                        else {
 134                                start_object_request(walker, obj_req);
 135                                return 1;
 136                        }
 137                }
 138        }
 139        return 0;
 140}
 141#endif
 142
 143static void prefetch(struct walker *walker, unsigned char *sha1)
 144{
 145        struct object_request *newreq;
 146        struct walker_data *data = walker->data;
 147
 148        newreq = xmalloc(sizeof(*newreq));
 149        newreq->walker = walker;
 150        hashcpy(newreq->sha1, sha1);
 151        newreq->repo = data->alt;
 152        newreq->state = WAITING;
 153        newreq->req = NULL;
 154
 155        http_is_verbose = walker->get_verbosely;
 156        list_add_tail(&newreq->node, &object_queue_head);
 157
 158#ifdef USE_CURL_MULTI
 159        fill_active_slots();
 160        step_active_slots();
 161#endif
 162}
 163
 164static int is_alternate_allowed(const char *url)
 165{
 166        const char *protocols[] = {
 167                "http", "https", "ftp", "ftps"
 168        };
 169        int i;
 170
 171        if (http_follow_config != HTTP_FOLLOW_ALWAYS) {
 172                warning("alternate disabled by http.followRedirects: %s", url);
 173                return 0;
 174        }
 175
 176        for (i = 0; i < ARRAY_SIZE(protocols); i++) {
 177                const char *end;
 178                if (skip_prefix(url, protocols[i], &end) &&
 179                    starts_with(end, "://"))
 180                        break;
 181        }
 182
 183        if (i >= ARRAY_SIZE(protocols)) {
 184                warning("ignoring alternate with unknown protocol: %s", url);
 185                return 0;
 186        }
 187        if (!is_transport_allowed(protocols[i], 0)) {
 188                warning("ignoring alternate with restricted protocol: %s", url);
 189                return 0;
 190        }
 191
 192        return 1;
 193}
 194
 195static void process_alternates_response(void *callback_data)
 196{
 197        struct alternates_request *alt_req =
 198                (struct alternates_request *)callback_data;
 199        struct walker *walker = alt_req->walker;
 200        struct walker_data *cdata = walker->data;
 201        struct active_request_slot *slot = alt_req->slot;
 202        struct alt_base *tail = cdata->alt;
 203        const char *base = alt_req->base;
 204        const char null_byte = '\0';
 205        char *data;
 206        int i = 0;
 207
 208        if (alt_req->http_specific) {
 209                if (slot->curl_result != CURLE_OK ||
 210                    !alt_req->buffer->len) {
 211
 212                        /* Try reusing the slot to get non-http alternates */
 213                        alt_req->http_specific = 0;
 214                        strbuf_reset(alt_req->url);
 215                        strbuf_addf(alt_req->url, "%s/objects/info/alternates",
 216                                    base);
 217                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 218                                         alt_req->url->buf);
 219                        active_requests++;
 220                        slot->in_use = 1;
 221                        if (slot->finished != NULL)
 222                                (*slot->finished) = 0;
 223                        if (!start_active_slot(slot)) {
 224                                cdata->got_alternates = -1;
 225                                slot->in_use = 0;
 226                                if (slot->finished != NULL)
 227                                        (*slot->finished) = 1;
 228                        }
 229                        return;
 230                }
 231        } else if (slot->curl_result != CURLE_OK) {
 232                if (!missing_target(slot)) {
 233                        cdata->got_alternates = -1;
 234                        return;
 235                }
 236        }
 237
 238        fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
 239        alt_req->buffer->len--;
 240        data = alt_req->buffer->buf;
 241
 242        while (i < alt_req->buffer->len) {
 243                int posn = i;
 244                while (posn < alt_req->buffer->len && data[posn] != '\n')
 245                        posn++;
 246                if (data[posn] == '\n') {
 247                        int okay = 0;
 248                        int serverlen = 0;
 249                        struct alt_base *newalt;
 250                        if (data[i] == '/') {
 251                                /*
 252                                 * This counts
 253                                 * http://git.host/pub/scm/linux.git/
 254                                 * -----------here^
 255                                 * so memcpy(dst, base, serverlen) will
 256                                 * copy up to "...git.host".
 257                                 */
 258                                const char *colon_ss = strstr(base,"://");
 259                                if (colon_ss) {
 260                                        serverlen = (strchr(colon_ss + 3, '/')
 261                                                     - base);
 262                                        okay = 1;
 263                                }
 264                        } else if (!memcmp(data + i, "../", 3)) {
 265                                /*
 266                                 * Relative URL; chop the corresponding
 267                                 * number of subpath from base (and ../
 268                                 * from data), and concatenate the result.
 269                                 *
 270                                 * The code first drops ../ from data, and
 271                                 * then drops one ../ from data and one path
 272                                 * from base.  IOW, one extra ../ is dropped
 273                                 * from data than path is dropped from base.
 274                                 *
 275                                 * This is not wrong.  The alternate in
 276                                 *     http://git.host/pub/scm/linux.git/
 277                                 * to borrow from
 278                                 *     http://git.host/pub/scm/linus.git/
 279                                 * is ../../linus.git/objects/.  You need
 280                                 * two ../../ to borrow from your direct
 281                                 * neighbour.
 282                                 */
 283                                i += 3;
 284                                serverlen = strlen(base);
 285                                while (i + 2 < posn &&
 286                                       !memcmp(data + i, "../", 3)) {
 287                                        do {
 288                                                serverlen--;
 289                                        } while (serverlen &&
 290                                                 base[serverlen - 1] != '/');
 291                                        i += 3;
 292                                }
 293                                /* If the server got removed, give up. */
 294                                okay = strchr(base, ':') - base + 3 <
 295                                       serverlen;
 296                        } else if (alt_req->http_specific) {
 297                                char *colon = strchr(data + i, ':');
 298                                char *slash = strchr(data + i, '/');
 299                                if (colon && slash && colon < data + posn &&
 300                                    slash < data + posn && colon < slash) {
 301                                        okay = 1;
 302                                }
 303                        }
 304                        if (okay) {
 305                                struct strbuf target = STRBUF_INIT;
 306                                strbuf_add(&target, base, serverlen);
 307                                strbuf_add(&target, data + i, posn - i);
 308                                if (!strbuf_strip_suffix(&target, "objects")) {
 309                                        warning("ignoring alternate that does"
 310                                                " not end in 'objects': %s",
 311                                                target.buf);
 312                                        strbuf_release(&target);
 313                                } else if (is_alternate_allowed(target.buf)) {
 314                                        warning("adding alternate object store: %s",
 315                                                target.buf);
 316                                        newalt = xmalloc(sizeof(*newalt));
 317                                        newalt->next = NULL;
 318                                        newalt->base = strbuf_detach(&target, NULL);
 319                                        newalt->got_indices = 0;
 320                                        newalt->packs = NULL;
 321
 322                                        while (tail->next != NULL)
 323                                                tail = tail->next;
 324                                        tail->next = newalt;
 325                                } else {
 326                                        strbuf_release(&target);
 327                                }
 328                        }
 329                }
 330                i = posn + 1;
 331        }
 332
 333        cdata->got_alternates = 1;
 334}
 335
 336static void fetch_alternates(struct walker *walker, const char *base)
 337{
 338        struct strbuf buffer = STRBUF_INIT;
 339        struct strbuf url = STRBUF_INIT;
 340        struct active_request_slot *slot;
 341        struct alternates_request alt_req;
 342        struct walker_data *cdata = walker->data;
 343
 344        /*
 345         * If another request has already started fetching alternates,
 346         * wait for them to arrive and return to processing this request's
 347         * curl message
 348         */
 349#ifdef USE_CURL_MULTI
 350        while (cdata->got_alternates == 0) {
 351                step_active_slots();
 352        }
 353#endif
 354
 355        /* Nothing to do if they've already been fetched */
 356        if (cdata->got_alternates == 1)
 357                return;
 358
 359        /* Start the fetch */
 360        cdata->got_alternates = 0;
 361
 362        if (walker->get_verbosely)
 363                fprintf(stderr, "Getting alternates list for %s\n", base);
 364
 365        strbuf_addf(&url, "%s/objects/info/http-alternates", base);
 366
 367        /*
 368         * Use a callback to process the result, since another request
 369         * may fail and need to have alternates loaded before continuing
 370         */
 371        slot = get_active_slot();
 372        slot->callback_func = process_alternates_response;
 373        alt_req.walker = walker;
 374        slot->callback_data = &alt_req;
 375
 376        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 377        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 378        curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
 379
 380        alt_req.base = base;
 381        alt_req.url = &url;
 382        alt_req.buffer = &buffer;
 383        alt_req.http_specific = 1;
 384        alt_req.slot = slot;
 385
 386        if (start_active_slot(slot))
 387                run_active_slot(slot);
 388        else
 389                cdata->got_alternates = -1;
 390
 391        strbuf_release(&buffer);
 392        strbuf_release(&url);
 393}
 394
 395static int fetch_indices(struct walker *walker, struct alt_base *repo)
 396{
 397        int ret;
 398
 399        if (repo->got_indices)
 400                return 0;
 401
 402        if (walker->get_verbosely)
 403                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 404
 405        switch (http_get_info_packs(repo->base, &repo->packs)) {
 406        case HTTP_OK:
 407        case HTTP_MISSING_TARGET:
 408                repo->got_indices = 1;
 409                ret = 0;
 410                break;
 411        default:
 412                repo->got_indices = 0;
 413                ret = -1;
 414        }
 415
 416        return ret;
 417}
 418
 419static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 420{
 421        struct packed_git *target;
 422        int ret;
 423        struct slot_results results;
 424        struct http_pack_request *preq;
 425
 426        if (fetch_indices(walker, repo))
 427                return -1;
 428        target = find_sha1_pack(sha1, repo->packs);
 429        if (!target)
 430                return -1;
 431
 432        if (walker->get_verbosely) {
 433                fprintf(stderr, "Getting pack %s\n",
 434                        sha1_to_hex(target->sha1));
 435                fprintf(stderr, " which contains %s\n",
 436                        sha1_to_hex(sha1));
 437        }
 438
 439        preq = new_http_pack_request(target, repo->base);
 440        if (preq == NULL)
 441                goto abort;
 442        preq->lst = &repo->packs;
 443        preq->slot->results = &results;
 444
 445        if (start_active_slot(preq->slot)) {
 446                run_active_slot(preq->slot);
 447                if (results.curl_result != CURLE_OK) {
 448                        error("Unable to get pack file %s\n%s", preq->url,
 449                              curl_errorstr);
 450                        goto abort;
 451                }
 452        } else {
 453                error("Unable to start request");
 454                goto abort;
 455        }
 456
 457        ret = finish_http_pack_request(preq);
 458        release_http_pack_request(preq);
 459        if (ret)
 460                return ret;
 461
 462        return 0;
 463
 464abort:
 465        return -1;
 466}
 467
 468static void abort_object_request(struct object_request *obj_req)
 469{
 470        release_object_request(obj_req);
 471}
 472
 473static int fetch_object(struct walker *walker, unsigned char *sha1)
 474{
 475        char *hex = sha1_to_hex(sha1);
 476        int ret = 0;
 477        struct object_request *obj_req = NULL;
 478        struct http_object_request *req;
 479        struct list_head *pos, *head = &object_queue_head;
 480
 481        list_for_each(pos, head) {
 482                obj_req = list_entry(pos, struct object_request, node);
 483                if (!hashcmp(obj_req->sha1, sha1))
 484                        break;
 485        }
 486        if (obj_req == NULL)
 487                return error("Couldn't find request for %s in the queue", hex);
 488
 489        if (has_sha1_file(obj_req->sha1)) {
 490                if (obj_req->req != NULL)
 491                        abort_http_object_request(obj_req->req);
 492                abort_object_request(obj_req);
 493                return 0;
 494        }
 495
 496#ifdef USE_CURL_MULTI
 497        while (obj_req->state == WAITING)
 498                step_active_slots();
 499#else
 500        start_object_request(walker, obj_req);
 501#endif
 502
 503        /*
 504         * obj_req->req might change when fetching alternates in the callback
 505         * process_object_response; therefore, the "shortcut" variable, req,
 506         * is used only after we're done with slots.
 507         */
 508        while (obj_req->state == ACTIVE)
 509                run_active_slot(obj_req->req->slot);
 510
 511        req = obj_req->req;
 512
 513        if (req->localfile != -1) {
 514                close(req->localfile);
 515                req->localfile = -1;
 516        }
 517
 518        /*
 519         * we turned off CURLOPT_FAILONERROR to avoid losing a
 520         * persistent connection and got CURLE_OK.
 521         */
 522        if (req->http_code >= 300 && req->curl_result == CURLE_OK &&
 523                        (starts_with(req->url, "http://") ||
 524                         starts_with(req->url, "https://"))) {
 525                req->curl_result = CURLE_HTTP_RETURNED_ERROR;
 526                xsnprintf(req->errorstr, sizeof(req->errorstr),
 527                          "HTTP request failed");
 528        }
 529
 530        if (obj_req->state == ABORTED) {
 531                ret = error("Request for %s aborted", hex);
 532        } else if (req->curl_result != CURLE_OK &&
 533                   req->http_code != 416) {
 534                if (missing_target(req))
 535                        ret = -1; /* Be silent, it is probably in a pack. */
 536                else
 537                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 538                                    req->errorstr, req->curl_result,
 539                                    req->http_code, hex);
 540        } else if (req->zret != Z_STREAM_END) {
 541                walker->corrupt_object_found++;
 542                ret = error("File %s (%s) corrupt", hex, req->url);
 543        } else if (hashcmp(obj_req->sha1, req->real_sha1)) {
 544                ret = error("File %s has bad hash", hex);
 545        } else if (req->rename < 0) {
 546                ret = error("unable to write sha1 filename %s",
 547                            sha1_file_name(req->sha1));
 548        }
 549
 550        release_http_object_request(req);
 551        release_object_request(obj_req);
 552        return ret;
 553}
 554
 555static int fetch(struct walker *walker, unsigned char *sha1)
 556{
 557        struct walker_data *data = walker->data;
 558        struct alt_base *altbase = data->alt;
 559
 560        if (!fetch_object(walker, sha1))
 561                return 0;
 562        while (altbase) {
 563                if (!http_fetch_pack(walker, altbase, sha1))
 564                        return 0;
 565                fetch_alternates(walker, data->alt->base);
 566                altbase = altbase->next;
 567        }
 568        return error("Unable to find %s under %s", sha1_to_hex(sha1),
 569                     data->alt->base);
 570}
 571
 572static int fetch_ref(struct walker *walker, struct ref *ref)
 573{
 574        struct walker_data *data = walker->data;
 575        return http_fetch_ref(data->alt->base, ref);
 576}
 577
 578static void cleanup(struct walker *walker)
 579{
 580        struct walker_data *data = walker->data;
 581        struct alt_base *alt, *alt_next;
 582
 583        if (data) {
 584                alt = data->alt;
 585                while (alt) {
 586                        alt_next = alt->next;
 587
 588                        free(alt->base);
 589                        free(alt);
 590
 591                        alt = alt_next;
 592                }
 593                free(data);
 594                walker->data = NULL;
 595        }
 596}
 597
 598struct walker *get_http_walker(const char *url)
 599{
 600        char *s;
 601        struct walker_data *data = xmalloc(sizeof(struct walker_data));
 602        struct walker *walker = xmalloc(sizeof(struct walker));
 603
 604        data->alt = xmalloc(sizeof(*data->alt));
 605        data->alt->base = xstrdup(url);
 606        for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 607                *s = 0;
 608
 609        data->alt->got_indices = 0;
 610        data->alt->packs = NULL;
 611        data->alt->next = NULL;
 612        data->got_alternates = -1;
 613
 614        walker->corrupt_object_found = 0;
 615        walker->fetch = fetch;
 616        walker->fetch_ref = fetch_ref;
 617        walker->prefetch = prefetch;
 618        walker->cleanup = cleanup;
 619        walker->data = data;
 620
 621#ifdef USE_CURL_MULTI
 622        add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 623#endif
 624
 625        return walker;
 626}