Andrew's git / gitweb.git / http-walker.c
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http-walker.con commit object-store: close all packs upon clearing the object store (d0b5986)
   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#include "packfile.h"
   8#include "object-store.h"
   9
  10struct alt_base {
  11        char *base;
  12        int got_indices;
  13        struct packed_git *packs;
  14        struct alt_base *next;
  15};
  16
  17enum object_request_state {
  18        WAITING,
  19        ABORTED,
  20        ACTIVE,
  21        COMPLETE
  22};
  23
  24struct object_request {
  25        struct walker *walker;
  26        unsigned char sha1[20];
  27        struct alt_base *repo;
  28        enum object_request_state state;
  29        struct http_object_request *req;
  30        struct list_head node;
  31};
  32
  33struct alternates_request {
  34        struct walker *walker;
  35        const char *base;
  36        struct strbuf *url;
  37        struct strbuf *buffer;
  38        struct active_request_slot *slot;
  39        int http_specific;
  40};
  41
  42struct walker_data {
  43        const char *url;
  44        int got_alternates;
  45        struct alt_base *alt;
  46};
  47
  48static LIST_HEAD(object_queue_head);
  49
  50static void fetch_alternates(struct walker *walker, const char *base);
  51
  52static void process_object_response(void *callback_data);
  53
  54static void start_object_request(struct walker *walker,
  55                                 struct object_request *obj_req)
  56{
  57        struct active_request_slot *slot;
  58        struct http_object_request *req;
  59
  60        req = new_http_object_request(obj_req->repo->base, obj_req->sha1);
  61        if (req == NULL) {
  62                obj_req->state = ABORTED;
  63                return;
  64        }
  65        obj_req->req = req;
  66
  67        slot = req->slot;
  68        slot->callback_func = process_object_response;
  69        slot->callback_data = obj_req;
  70
  71        /* Try to get the request started, abort the request on error */
  72        obj_req->state = ACTIVE;
  73        if (!start_active_slot(slot)) {
  74                obj_req->state = ABORTED;
  75                release_http_object_request(req);
  76                return;
  77        }
  78}
  79
  80static void finish_object_request(struct object_request *obj_req)
  81{
  82        if (finish_http_object_request(obj_req->req))
  83                return;
  84
  85        if (obj_req->req->rename == 0)
  86                walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
  87}
  88
  89static void process_object_response(void *callback_data)
  90{
  91        struct object_request *obj_req =
  92                (struct object_request *)callback_data;
  93        struct walker *walker = obj_req->walker;
  94        struct walker_data *data = walker->data;
  95        struct alt_base *alt = data->alt;
  96
  97        process_http_object_request(obj_req->req);
  98        obj_req->state = COMPLETE;
  99
 100        /* Use alternates if necessary */
 101        if (missing_target(obj_req->req)) {
 102                fetch_alternates(walker, alt->base);
 103                if (obj_req->repo->next != NULL) {
 104                        obj_req->repo =
 105                                obj_req->repo->next;
 106                        release_http_object_request(obj_req->req);
 107                        start_object_request(walker, obj_req);
 108                        return;
 109                }
 110        }
 111
 112        finish_object_request(obj_req);
 113}
 114
 115static void release_object_request(struct object_request *obj_req)
 116{
 117        if (obj_req->req !=NULL && obj_req->req->localfile != -1)
 118                error("fd leakage in release: %d", obj_req->req->localfile);
 119
 120        list_del(&obj_req->node);
 121        free(obj_req);
 122}
 123
 124#ifdef USE_CURL_MULTI
 125static int fill_active_slot(struct walker *walker)
 126{
 127        struct object_request *obj_req;
 128        struct list_head *pos, *tmp, *head = &object_queue_head;
 129
 130        list_for_each_safe(pos, tmp, head) {
 131                obj_req = list_entry(pos, struct object_request, node);
 132                if (obj_req->state == WAITING) {
 133                        if (has_sha1_file(obj_req->sha1))
 134                                obj_req->state = COMPLETE;
 135                        else {
 136                                start_object_request(walker, obj_req);
 137                                return 1;
 138                        }
 139                }
 140        }
 141        return 0;
 142}
 143#endif
 144
 145static void prefetch(struct walker *walker, unsigned char *sha1)
 146{
 147        struct object_request *newreq;
 148        struct walker_data *data = walker->data;
 149
 150        newreq = xmalloc(sizeof(*newreq));
 151        newreq->walker = walker;
 152        hashcpy(newreq->sha1, sha1);
 153        newreq->repo = data->alt;
 154        newreq->state = WAITING;
 155        newreq->req = NULL;
 156
 157        http_is_verbose = walker->get_verbosely;
 158        list_add_tail(&newreq->node, &object_queue_head);
 159
 160#ifdef USE_CURL_MULTI
 161        fill_active_slots();
 162        step_active_slots();
 163#endif
 164}
 165
 166static int is_alternate_allowed(const char *url)
 167{
 168        const char *protocols[] = {
 169                "http", "https", "ftp", "ftps"
 170        };
 171        int i;
 172
 173        if (http_follow_config != HTTP_FOLLOW_ALWAYS) {
 174                warning("alternate disabled by http.followRedirects: %s", url);
 175                return 0;
 176        }
 177
 178        for (i = 0; i < ARRAY_SIZE(protocols); i++) {
 179                const char *end;
 180                if (skip_prefix(url, protocols[i], &end) &&
 181                    starts_with(end, "://"))
 182                        break;
 183        }
 184
 185        if (i >= ARRAY_SIZE(protocols)) {
 186                warning("ignoring alternate with unknown protocol: %s", url);
 187                return 0;
 188        }
 189        if (!is_transport_allowed(protocols[i], 0)) {
 190                warning("ignoring alternate with restricted protocol: %s", url);
 191                return 0;
 192        }
 193
 194        return 1;
 195}
 196
 197static void process_alternates_response(void *callback_data)
 198{
 199        struct alternates_request *alt_req =
 200                (struct alternates_request *)callback_data;
 201        struct walker *walker = alt_req->walker;
 202        struct walker_data *cdata = walker->data;
 203        struct active_request_slot *slot = alt_req->slot;
 204        struct alt_base *tail = cdata->alt;
 205        const char *base = alt_req->base;
 206        const char null_byte = '\0';
 207        char *data;
 208        int i = 0;
 209
 210        if (alt_req->http_specific) {
 211                if (slot->curl_result != CURLE_OK ||
 212                    !alt_req->buffer->len) {
 213
 214                        /* Try reusing the slot to get non-http alternates */
 215                        alt_req->http_specific = 0;
 216                        strbuf_reset(alt_req->url);
 217                        strbuf_addf(alt_req->url, "%s/objects/info/alternates",
 218                                    base);
 219                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 220                                         alt_req->url->buf);
 221                        active_requests++;
 222                        slot->in_use = 1;
 223                        if (slot->finished != NULL)
 224                                (*slot->finished) = 0;
 225                        if (!start_active_slot(slot)) {
 226                                cdata->got_alternates = -1;
 227                                slot->in_use = 0;
 228                                if (slot->finished != NULL)
 229                                        (*slot->finished) = 1;
 230                        }
 231                        return;
 232                }
 233        } else if (slot->curl_result != CURLE_OK) {
 234                if (!missing_target(slot)) {
 235                        cdata->got_alternates = -1;
 236                        return;
 237                }
 238        }
 239
 240        fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
 241        alt_req->buffer->len--;
 242        data = alt_req->buffer->buf;
 243
 244        while (i < alt_req->buffer->len) {
 245                int posn = i;
 246                while (posn < alt_req->buffer->len && data[posn] != '\n')
 247                        posn++;
 248                if (data[posn] == '\n') {
 249                        int okay = 0;
 250                        int serverlen = 0;
 251                        struct alt_base *newalt;
 252                        if (data[i] == '/') {
 253                                /*
 254                                 * This counts
 255                                 * http://git.host/pub/scm/linux.git/
 256                                 * -----------here^
 257                                 * so memcpy(dst, base, serverlen) will
 258                                 * copy up to "...git.host".
 259                                 */
 260                                const char *colon_ss = strstr(base,"://");
 261                                if (colon_ss) {
 262                                        serverlen = (strchr(colon_ss + 3, '/')
 263                                                     - base);
 264                                        okay = 1;
 265                                }
 266                        } else if (!memcmp(data + i, "../", 3)) {
 267                                /*
 268                                 * Relative URL; chop the corresponding
 269                                 * number of subpath from base (and ../
 270                                 * from data), and concatenate the result.
 271                                 *
 272                                 * The code first drops ../ from data, and
 273                                 * then drops one ../ from data and one path
 274                                 * from base.  IOW, one extra ../ is dropped
 275                                 * from data than path is dropped from base.
 276                                 *
 277                                 * This is not wrong.  The alternate in
 278                                 *     http://git.host/pub/scm/linux.git/
 279                                 * to borrow from
 280                                 *     http://git.host/pub/scm/linus.git/
 281                                 * is ../../linus.git/objects/.  You need
 282                                 * two ../../ to borrow from your direct
 283                                 * neighbour.
 284                                 */
 285                                i += 3;
 286                                serverlen = strlen(base);
 287                                while (i + 2 < posn &&
 288                                       !memcmp(data + i, "../", 3)) {
 289                                        do {
 290                                                serverlen--;
 291                                        } while (serverlen &&
 292                                                 base[serverlen - 1] != '/');
 293                                        i += 3;
 294                                }
 295                                /* If the server got removed, give up. */
 296                                okay = strchr(base, ':') - base + 3 <
 297                                       serverlen;
 298                        } else if (alt_req->http_specific) {
 299                                char *colon = strchr(data + i, ':');
 300                                char *slash = strchr(data + i, '/');
 301                                if (colon && slash && colon < data + posn &&
 302                                    slash < data + posn && colon < slash) {
 303                                        okay = 1;
 304                                }
 305                        }
 306                        if (okay) {
 307                                struct strbuf target = STRBUF_INIT;
 308                                strbuf_add(&target, base, serverlen);
 309                                strbuf_add(&target, data + i, posn - i);
 310                                if (!strbuf_strip_suffix(&target, "objects")) {
 311                                        warning("ignoring alternate that does"
 312                                                " not end in 'objects': %s",
 313                                                target.buf);
 314                                        strbuf_release(&target);
 315                                } else if (is_alternate_allowed(target.buf)) {
 316                                        warning("adding alternate object store: %s",
 317                                                target.buf);
 318                                        newalt = xmalloc(sizeof(*newalt));
 319                                        newalt->next = NULL;
 320                                        newalt->base = strbuf_detach(&target, NULL);
 321                                        newalt->got_indices = 0;
 322                                        newalt->packs = NULL;
 323
 324                                        while (tail->next != NULL)
 325                                                tail = tail->next;
 326                                        tail->next = newalt;
 327                                } else {
 328                                        strbuf_release(&target);
 329                                }
 330                        }
 331                }
 332                i = posn + 1;
 333        }
 334
 335        cdata->got_alternates = 1;
 336}
 337
 338static void fetch_alternates(struct walker *walker, const char *base)
 339{
 340        struct strbuf buffer = STRBUF_INIT;
 341        struct strbuf url = STRBUF_INIT;
 342        struct active_request_slot *slot;
 343        struct alternates_request alt_req;
 344        struct walker_data *cdata = walker->data;
 345
 346        /*
 347         * If another request has already started fetching alternates,
 348         * wait for them to arrive and return to processing this request's
 349         * curl message
 350         */
 351#ifdef USE_CURL_MULTI
 352        while (cdata->got_alternates == 0) {
 353                step_active_slots();
 354        }
 355#endif
 356
 357        /* Nothing to do if they've already been fetched */
 358        if (cdata->got_alternates == 1)
 359                return;
 360
 361        /* Start the fetch */
 362        cdata->got_alternates = 0;
 363
 364        if (walker->get_verbosely)
 365                fprintf(stderr, "Getting alternates list for %s\n", base);
 366
 367        strbuf_addf(&url, "%s/objects/info/http-alternates", base);
 368
 369        /*
 370         * Use a callback to process the result, since another request
 371         * may fail and need to have alternates loaded before continuing
 372         */
 373        slot = get_active_slot();
 374        slot->callback_func = process_alternates_response;
 375        alt_req.walker = walker;
 376        slot->callback_data = &alt_req;
 377
 378        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 379        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 380        curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
 381
 382        alt_req.base = base;
 383        alt_req.url = &url;
 384        alt_req.buffer = &buffer;
 385        alt_req.http_specific = 1;
 386        alt_req.slot = slot;
 387
 388        if (start_active_slot(slot))
 389                run_active_slot(slot);
 390        else
 391                cdata->got_alternates = -1;
 392
 393        strbuf_release(&buffer);
 394        strbuf_release(&url);
 395}
 396
 397static int fetch_indices(struct walker *walker, struct alt_base *repo)
 398{
 399        int ret;
 400
 401        if (repo->got_indices)
 402                return 0;
 403
 404        if (walker->get_verbosely)
 405                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 406
 407        switch (http_get_info_packs(repo->base, &repo->packs)) {
 408        case HTTP_OK:
 409        case HTTP_MISSING_TARGET:
 410                repo->got_indices = 1;
 411                ret = 0;
 412                break;
 413        default:
 414                repo->got_indices = 0;
 415                ret = -1;
 416        }
 417
 418        return ret;
 419}
 420
 421static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 422{
 423        struct packed_git *target;
 424        int ret;
 425        struct slot_results results;
 426        struct http_pack_request *preq;
 427
 428        if (fetch_indices(walker, repo))
 429                return -1;
 430        target = find_sha1_pack(sha1, repo->packs);
 431        if (!target)
 432                return -1;
 433
 434        if (walker->get_verbosely) {
 435                fprintf(stderr, "Getting pack %s\n",
 436                        sha1_to_hex(target->sha1));
 437                fprintf(stderr, " which contains %s\n",
 438                        sha1_to_hex(sha1));
 439        }
 440
 441        preq = new_http_pack_request(target, repo->base);
 442        if (preq == NULL)
 443                goto abort;
 444        preq->lst = &repo->packs;
 445        preq->slot->results = &results;
 446
 447        if (start_active_slot(preq->slot)) {
 448                run_active_slot(preq->slot);
 449                if (results.curl_result != CURLE_OK) {
 450                        error("Unable to get pack file %s\n%s", preq->url,
 451                              curl_errorstr);
 452                        goto abort;
 453                }
 454        } else {
 455                error("Unable to start request");
 456                goto abort;
 457        }
 458
 459        ret = finish_http_pack_request(preq);
 460        release_http_pack_request(preq);
 461        if (ret)
 462                return ret;
 463
 464        return 0;
 465
 466abort:
 467        return -1;
 468}
 469
 470static void abort_object_request(struct object_request *obj_req)
 471{
 472        release_object_request(obj_req);
 473}
 474
 475static int fetch_object(struct walker *walker, unsigned char *sha1)
 476{
 477        char *hex = sha1_to_hex(sha1);
 478        int ret = 0;
 479        struct object_request *obj_req = NULL;
 480        struct http_object_request *req;
 481        struct list_head *pos, *head = &object_queue_head;
 482
 483        list_for_each(pos, head) {
 484                obj_req = list_entry(pos, struct object_request, node);
 485                if (!hashcmp(obj_req->sha1, sha1))
 486                        break;
 487        }
 488        if (obj_req == NULL)
 489                return error("Couldn't find request for %s in the queue", hex);
 490
 491        if (has_sha1_file(obj_req->sha1)) {
 492                if (obj_req->req != NULL)
 493                        abort_http_object_request(obj_req->req);
 494                abort_object_request(obj_req);
 495                return 0;
 496        }
 497
 498#ifdef USE_CURL_MULTI
 499        while (obj_req->state == WAITING)
 500                step_active_slots();
 501#else
 502        start_object_request(walker, obj_req);
 503#endif
 504
 505        /*
 506         * obj_req->req might change when fetching alternates in the callback
 507         * process_object_response; therefore, the "shortcut" variable, req,
 508         * is used only after we're done with slots.
 509         */
 510        while (obj_req->state == ACTIVE)
 511                run_active_slot(obj_req->req->slot);
 512
 513        req = obj_req->req;
 514
 515        if (req->localfile != -1) {
 516                close(req->localfile);
 517                req->localfile = -1;
 518        }
 519
 520        /*
 521         * we turned off CURLOPT_FAILONERROR to avoid losing a
 522         * persistent connection and got CURLE_OK.
 523         */
 524        if (req->http_code >= 300 && req->curl_result == CURLE_OK &&
 525                        (starts_with(req->url, "http://") ||
 526                         starts_with(req->url, "https://"))) {
 527                req->curl_result = CURLE_HTTP_RETURNED_ERROR;
 528                xsnprintf(req->errorstr, sizeof(req->errorstr),
 529                          "HTTP request failed");
 530        }
 531
 532        if (obj_req->state == ABORTED) {
 533                ret = error("Request for %s aborted", hex);
 534        } else if (req->curl_result != CURLE_OK &&
 535                   req->http_code != 416) {
 536                if (missing_target(req))
 537                        ret = -1; /* Be silent, it is probably in a pack. */
 538                else
 539                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 540                                    req->errorstr, req->curl_result,
 541                                    req->http_code, hex);
 542        } else if (req->zret != Z_STREAM_END) {
 543                walker->corrupt_object_found++;
 544                ret = error("File %s (%s) corrupt", hex, req->url);
 545        } else if (hashcmp(obj_req->sha1, req->real_sha1)) {
 546                ret = error("File %s has bad hash", hex);
 547        } else if (req->rename < 0) {
 548                struct strbuf buf = STRBUF_INIT;
 549                sha1_file_name(&buf, req->sha1);
 550                ret = error("unable to write sha1 filename %s", buf.buf);
 551                strbuf_release(&buf);
 552        }
 553
 554        release_http_object_request(req);
 555        release_object_request(obj_req);
 556        return ret;
 557}
 558
 559static int fetch(struct walker *walker, unsigned char *sha1)
 560{
 561        struct walker_data *data = walker->data;
 562        struct alt_base *altbase = data->alt;
 563
 564        if (!fetch_object(walker, sha1))
 565                return 0;
 566        while (altbase) {
 567                if (!http_fetch_pack(walker, altbase, sha1))
 568                        return 0;
 569                fetch_alternates(walker, data->alt->base);
 570                altbase = altbase->next;
 571        }
 572        return error("Unable to find %s under %s", sha1_to_hex(sha1),
 573                     data->alt->base);
 574}
 575
 576static int fetch_ref(struct walker *walker, struct ref *ref)
 577{
 578        struct walker_data *data = walker->data;
 579        return http_fetch_ref(data->alt->base, ref);
 580}
 581
 582static void cleanup(struct walker *walker)
 583{
 584        struct walker_data *data = walker->data;
 585        struct alt_base *alt, *alt_next;
 586
 587        if (data) {
 588                alt = data->alt;
 589                while (alt) {
 590                        alt_next = alt->next;
 591
 592                        free(alt->base);
 593                        free(alt);
 594
 595                        alt = alt_next;
 596                }
 597                free(data);
 598                walker->data = NULL;
 599        }
 600}
 601
 602struct walker *get_http_walker(const char *url)
 603{
 604        char *s;
 605        struct walker_data *data = xmalloc(sizeof(struct walker_data));
 606        struct walker *walker = xmalloc(sizeof(struct walker));
 607
 608        data->alt = xmalloc(sizeof(*data->alt));
 609        data->alt->base = xstrdup(url);
 610        for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 611                *s = 0;
 612
 613        data->alt->got_indices = 0;
 614        data->alt->packs = NULL;
 615        data->alt->next = NULL;
 616        data->got_alternates = -1;
 617
 618        walker->corrupt_object_found = 0;
 619        walker->fetch = fetch;
 620        walker->fetch_ref = fetch_ref;
 621        walker->prefetch = prefetch;
 622        walker->cleanup = cleanup;
 623        walker->data = data;
 624
 625#ifdef USE_CURL_MULTI
 626        add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 627#endif
 628
 629        return walker;
 630}