Andrew's git / gitweb.git / http-walker.c
?
http-walker.con commit t4030: abstract away SHA-1-specific constants (a6c5799)
   1#include "cache.h"
   2#include "repository.h"
   3#include "commit.h"
   4#include "walker.h"
   5#include "http.h"
   6#include "list.h"
   7#include "transport.h"
   8#include "packfile.h"
   9#include "object-store.h"
  10
  11struct alt_base {
  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        struct walker *walker;
  27        struct object_id oid;
  28        struct alt_base *repo;
  29        enum object_request_state state;
  30        struct http_object_request *req;
  31        struct list_head node;
  32};
  33
  34struct alternates_request {
  35        struct walker *walker;
  36        const char *base;
  37        struct strbuf *url;
  38        struct strbuf *buffer;
  39        struct active_request_slot *slot;
  40        int http_specific;
  41};
  42
  43struct walker_data {
  44        const char *url;
  45        int got_alternates;
  46        struct alt_base *alt;
  47};
  48
  49static LIST_HEAD(object_queue_head);
  50
  51static void fetch_alternates(struct walker *walker, const char *base);
  52
  53static void process_object_response(void *callback_data);
  54
  55static void start_object_request(struct walker *walker,
  56                                 struct object_request *obj_req)
  57{
  58        struct active_request_slot *slot;
  59        struct http_object_request *req;
  60
  61        req = new_http_object_request(obj_req->repo->base, obj_req->oid.hash);
  62        if (req == NULL) {
  63                obj_req->state = ABORTED;
  64                return;
  65        }
  66        obj_req->req = req;
  67
  68        slot = req->slot;
  69        slot->callback_func = process_object_response;
  70        slot->callback_data = obj_req;
  71
  72        /* Try to get the request started, abort the request on error */
  73        obj_req->state = ACTIVE;
  74        if (!start_active_slot(slot)) {
  75                obj_req->state = ABORTED;
  76                release_http_object_request(req);
  77                return;
  78        }
  79}
  80
  81static void finish_object_request(struct object_request *obj_req)
  82{
  83        if (finish_http_object_request(obj_req->req))
  84                return;
  85
  86        if (obj_req->req->rename == 0)
  87                walker_say(obj_req->walker, "got %s\n", oid_to_hex(&obj_req->oid));
  88}
  89
  90static void process_object_response(void *callback_data)
  91{
  92        struct object_request *obj_req =
  93                (struct object_request *)callback_data;
  94        struct walker *walker = obj_req->walker;
  95        struct walker_data *data = walker->data;
  96        struct alt_base *alt = data->alt;
  97
  98        process_http_object_request(obj_req->req);
  99        obj_req->state = COMPLETE;
 100
 101        /* Use alternates if necessary */
 102        if (missing_target(obj_req->req)) {
 103                fetch_alternates(walker, alt->base);
 104                if (obj_req->repo->next != NULL) {
 105                        obj_req->repo =
 106                                obj_req->repo->next;
 107                        release_http_object_request(obj_req->req);
 108                        start_object_request(walker, obj_req);
 109                        return;
 110                }
 111        }
 112
 113        finish_object_request(obj_req);
 114}
 115
 116static void release_object_request(struct object_request *obj_req)
 117{
 118        if (obj_req->req !=NULL && obj_req->req->localfile != -1)
 119                error("fd leakage in release: %d", obj_req->req->localfile);
 120
 121        list_del(&obj_req->node);
 122        free(obj_req);
 123}
 124
 125#ifdef USE_CURL_MULTI
 126static int fill_active_slot(struct walker *walker)
 127{
 128        struct object_request *obj_req;
 129        struct list_head *pos, *tmp, *head = &object_queue_head;
 130
 131        list_for_each_safe(pos, tmp, head) {
 132                obj_req = list_entry(pos, struct object_request, node);
 133                if (obj_req->state == WAITING) {
 134                        if (has_sha1_file(obj_req->oid.hash))
 135                                obj_req->state = COMPLETE;
 136                        else {
 137                                start_object_request(walker, obj_req);
 138                                return 1;
 139                        }
 140                }
 141        }
 142        return 0;
 143}
 144#endif
 145
 146static void prefetch(struct walker *walker, unsigned char *sha1)
 147{
 148        struct object_request *newreq;
 149        struct walker_data *data = walker->data;
 150
 151        newreq = xmalloc(sizeof(*newreq));
 152        newreq->walker = walker;
 153        hashcpy(newreq->oid.hash, sha1);
 154        newreq->repo = data->alt;
 155        newreq->state = WAITING;
 156        newreq->req = NULL;
 157
 158        http_is_verbose = walker->get_verbosely;
 159        list_add_tail(&newreq->node, &object_queue_head);
 160
 161#ifdef USE_CURL_MULTI
 162        fill_active_slots();
 163        step_active_slots();
 164#endif
 165}
 166
 167static int is_alternate_allowed(const char *url)
 168{
 169        const char *protocols[] = {
 170                "http", "https", "ftp", "ftps"
 171        };
 172        int i;
 173
 174        if (http_follow_config != HTTP_FOLLOW_ALWAYS) {
 175                warning("alternate disabled by http.followRedirects: %s", url);
 176                return 0;
 177        }
 178
 179        for (i = 0; i < ARRAY_SIZE(protocols); i++) {
 180                const char *end;
 181                if (skip_prefix(url, protocols[i], &end) &&
 182                    starts_with(end, "://"))
 183                        break;
 184        }
 185
 186        if (i >= ARRAY_SIZE(protocols)) {
 187                warning("ignoring alternate with unknown protocol: %s", url);
 188                return 0;
 189        }
 190        if (!is_transport_allowed(protocols[i], 0)) {
 191                warning("ignoring alternate with restricted protocol: %s", url);
 192                return 0;
 193        }
 194
 195        return 1;
 196}
 197
 198static void process_alternates_response(void *callback_data)
 199{
 200        struct alternates_request *alt_req =
 201                (struct alternates_request *)callback_data;
 202        struct walker *walker = alt_req->walker;
 203        struct walker_data *cdata = walker->data;
 204        struct active_request_slot *slot = alt_req->slot;
 205        struct alt_base *tail = cdata->alt;
 206        const char *base = alt_req->base;
 207        const char null_byte = '\0';
 208        char *data;
 209        int i = 0;
 210
 211        if (alt_req->http_specific) {
 212                if (slot->curl_result != CURLE_OK ||
 213                    !alt_req->buffer->len) {
 214
 215                        /* Try reusing the slot to get non-http alternates */
 216                        alt_req->http_specific = 0;
 217                        strbuf_reset(alt_req->url);
 218                        strbuf_addf(alt_req->url, "%s/objects/info/alternates",
 219                                    base);
 220                        curl_easy_setopt(slot->curl, CURLOPT_URL,
 221                                         alt_req->url->buf);
 222                        active_requests++;
 223                        slot->in_use = 1;
 224                        if (slot->finished != NULL)
 225                                (*slot->finished) = 0;
 226                        if (!start_active_slot(slot)) {
 227                                cdata->got_alternates = -1;
 228                                slot->in_use = 0;
 229                                if (slot->finished != NULL)
 230                                        (*slot->finished) = 1;
 231                        }
 232                        return;
 233                }
 234        } else if (slot->curl_result != CURLE_OK) {
 235                if (!missing_target(slot)) {
 236                        cdata->got_alternates = -1;
 237                        return;
 238                }
 239        }
 240
 241        fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
 242        alt_req->buffer->len--;
 243        data = alt_req->buffer->buf;
 244
 245        while (i < alt_req->buffer->len) {
 246                int posn = i;
 247                while (posn < alt_req->buffer->len && data[posn] != '\n')
 248                        posn++;
 249                if (data[posn] == '\n') {
 250                        int okay = 0;
 251                        int serverlen = 0;
 252                        struct alt_base *newalt;
 253                        if (data[i] == '/') {
 254                                /*
 255                                 * This counts
 256                                 * http://git.host/pub/scm/linux.git/
 257                                 * -----------here^
 258                                 * so memcpy(dst, base, serverlen) will
 259                                 * copy up to "...git.host".
 260                                 */
 261                                const char *colon_ss = strstr(base,"://");
 262                                if (colon_ss) {
 263                                        serverlen = (strchr(colon_ss + 3, '/')
 264                                                     - base);
 265                                        okay = 1;
 266                                }
 267                        } else if (!memcmp(data + i, "../", 3)) {
 268                                /*
 269                                 * Relative URL; chop the corresponding
 270                                 * number of subpath from base (and ../
 271                                 * from data), and concatenate the result.
 272                                 *
 273                                 * The code first drops ../ from data, and
 274                                 * then drops one ../ from data and one path
 275                                 * from base.  IOW, one extra ../ is dropped
 276                                 * from data than path is dropped from base.
 277                                 *
 278                                 * This is not wrong.  The alternate in
 279                                 *     http://git.host/pub/scm/linux.git/
 280                                 * to borrow from
 281                                 *     http://git.host/pub/scm/linus.git/
 282                                 * is ../../linus.git/objects/.  You need
 283                                 * two ../../ to borrow from your direct
 284                                 * neighbour.
 285                                 */
 286                                i += 3;
 287                                serverlen = strlen(base);
 288                                while (i + 2 < posn &&
 289                                       !memcmp(data + i, "../", 3)) {
 290                                        do {
 291                                                serverlen--;
 292                                        } while (serverlen &&
 293                                                 base[serverlen - 1] != '/');
 294                                        i += 3;
 295                                }
 296                                /* If the server got removed, give up. */
 297                                okay = strchr(base, ':') - base + 3 <
 298                                       serverlen;
 299                        } else if (alt_req->http_specific) {
 300                                char *colon = strchr(data + i, ':');
 301                                char *slash = strchr(data + i, '/');
 302                                if (colon && slash && colon < data + posn &&
 303                                    slash < data + posn && colon < slash) {
 304                                        okay = 1;
 305                                }
 306                        }
 307                        if (okay) {
 308                                struct strbuf target = STRBUF_INIT;
 309                                strbuf_add(&target, base, serverlen);
 310                                strbuf_add(&target, data + i, posn - i);
 311                                if (!strbuf_strip_suffix(&target, "objects")) {
 312                                        warning("ignoring alternate that does"
 313                                                " not end in 'objects': %s",
 314                                                target.buf);
 315                                        strbuf_release(&target);
 316                                } else if (is_alternate_allowed(target.buf)) {
 317                                        warning("adding alternate object store: %s",
 318                                                target.buf);
 319                                        newalt = xmalloc(sizeof(*newalt));
 320                                        newalt->next = NULL;
 321                                        newalt->base = strbuf_detach(&target, NULL);
 322                                        newalt->got_indices = 0;
 323                                        newalt->packs = NULL;
 324
 325                                        while (tail->next != NULL)
 326                                                tail = tail->next;
 327                                        tail->next = newalt;
 328                                } else {
 329                                        strbuf_release(&target);
 330                                }
 331                        }
 332                }
 333                i = posn + 1;
 334        }
 335
 336        cdata->got_alternates = 1;
 337}
 338
 339static void fetch_alternates(struct walker *walker, const char *base)
 340{
 341        struct strbuf buffer = STRBUF_INIT;
 342        struct strbuf url = STRBUF_INIT;
 343        struct active_request_slot *slot;
 344        struct alternates_request alt_req;
 345        struct walker_data *cdata = walker->data;
 346
 347        /*
 348         * If another request has already started fetching alternates,
 349         * wait for them to arrive and return to processing this request's
 350         * curl message
 351         */
 352#ifdef USE_CURL_MULTI
 353        while (cdata->got_alternates == 0) {
 354                step_active_slots();
 355        }
 356#endif
 357
 358        /* Nothing to do if they've already been fetched */
 359        if (cdata->got_alternates == 1)
 360                return;
 361
 362        /* Start the fetch */
 363        cdata->got_alternates = 0;
 364
 365        if (walker->get_verbosely)
 366                fprintf(stderr, "Getting alternates list for %s\n", base);
 367
 368        strbuf_addf(&url, "%s/objects/info/http-alternates", base);
 369
 370        /*
 371         * Use a callback to process the result, since another request
 372         * may fail and need to have alternates loaded before continuing
 373         */
 374        slot = get_active_slot();
 375        slot->callback_func = process_alternates_response;
 376        alt_req.walker = walker;
 377        slot->callback_data = &alt_req;
 378
 379        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 380        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 381        curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
 382
 383        alt_req.base = base;
 384        alt_req.url = &url;
 385        alt_req.buffer = &buffer;
 386        alt_req.http_specific = 1;
 387        alt_req.slot = slot;
 388
 389        if (start_active_slot(slot))
 390                run_active_slot(slot);
 391        else
 392                cdata->got_alternates = -1;
 393
 394        strbuf_release(&buffer);
 395        strbuf_release(&url);
 396}
 397
 398static int fetch_indices(struct walker *walker, struct alt_base *repo)
 399{
 400        int ret;
 401
 402        if (repo->got_indices)
 403                return 0;
 404
 405        if (walker->get_verbosely)
 406                fprintf(stderr, "Getting pack list for %s\n", repo->base);
 407
 408        switch (http_get_info_packs(repo->base, &repo->packs)) {
 409        case HTTP_OK:
 410        case HTTP_MISSING_TARGET:
 411                repo->got_indices = 1;
 412                ret = 0;
 413                break;
 414        default:
 415                repo->got_indices = 0;
 416                ret = -1;
 417        }
 418
 419        return ret;
 420}
 421
 422static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 423{
 424        struct packed_git *target;
 425        int ret;
 426        struct slot_results results;
 427        struct http_pack_request *preq;
 428
 429        if (fetch_indices(walker, repo))
 430                return -1;
 431        target = find_sha1_pack(sha1, repo->packs);
 432        if (!target)
 433                return -1;
 434
 435        if (walker->get_verbosely) {
 436                fprintf(stderr, "Getting pack %s\n",
 437                        sha1_to_hex(target->sha1));
 438                fprintf(stderr, " which contains %s\n",
 439                        sha1_to_hex(sha1));
 440        }
 441
 442        preq = new_http_pack_request(target, repo->base);
 443        if (preq == NULL)
 444                goto abort;
 445        preq->lst = &repo->packs;
 446        preq->slot->results = &results;
 447
 448        if (start_active_slot(preq->slot)) {
 449                run_active_slot(preq->slot);
 450                if (results.curl_result != CURLE_OK) {
 451                        error("Unable to get pack file %s\n%s", preq->url,
 452                              curl_errorstr);
 453                        goto abort;
 454                }
 455        } else {
 456                error("Unable to start request");
 457                goto abort;
 458        }
 459
 460        ret = finish_http_pack_request(preq);
 461        release_http_pack_request(preq);
 462        if (ret)
 463                return ret;
 464
 465        return 0;
 466
 467abort:
 468        return -1;
 469}
 470
 471static void abort_object_request(struct object_request *obj_req)
 472{
 473        release_object_request(obj_req);
 474}
 475
 476static int fetch_object(struct walker *walker, unsigned char *sha1)
 477{
 478        char *hex = sha1_to_hex(sha1);
 479        int ret = 0;
 480        struct object_request *obj_req = NULL;
 481        struct http_object_request *req;
 482        struct list_head *pos, *head = &object_queue_head;
 483
 484        list_for_each(pos, head) {
 485                obj_req = list_entry(pos, struct object_request, node);
 486                if (!hashcmp(obj_req->oid.hash, sha1))
 487                        break;
 488        }
 489        if (obj_req == NULL)
 490                return error("Couldn't find request for %s in the queue", hex);
 491
 492        if (has_sha1_file(obj_req->oid.hash)) {
 493                if (obj_req->req != NULL)
 494                        abort_http_object_request(obj_req->req);
 495                abort_object_request(obj_req);
 496                return 0;
 497        }
 498
 499#ifdef USE_CURL_MULTI
 500        while (obj_req->state == WAITING)
 501                step_active_slots();
 502#else
 503        start_object_request(walker, obj_req);
 504#endif
 505
 506        /*
 507         * obj_req->req might change when fetching alternates in the callback
 508         * process_object_response; therefore, the "shortcut" variable, req,
 509         * is used only after we're done with slots.
 510         */
 511        while (obj_req->state == ACTIVE)
 512                run_active_slot(obj_req->req->slot);
 513
 514        req = obj_req->req;
 515
 516        if (req->localfile != -1) {
 517                close(req->localfile);
 518                req->localfile = -1;
 519        }
 520
 521        /*
 522         * we turned off CURLOPT_FAILONERROR to avoid losing a
 523         * persistent connection and got CURLE_OK.
 524         */
 525        if (req->http_code >= 300 && req->curl_result == CURLE_OK &&
 526                        (starts_with(req->url, "http://") ||
 527                         starts_with(req->url, "https://"))) {
 528                req->curl_result = CURLE_HTTP_RETURNED_ERROR;
 529                xsnprintf(req->errorstr, sizeof(req->errorstr),
 530                          "HTTP request failed");
 531        }
 532
 533        if (obj_req->state == ABORTED) {
 534                ret = error("Request for %s aborted", hex);
 535        } else if (req->curl_result != CURLE_OK &&
 536                   req->http_code != 416) {
 537                if (missing_target(req))
 538                        ret = -1; /* Be silent, it is probably in a pack. */
 539                else
 540                        ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 541                                    req->errorstr, req->curl_result,
 542                                    req->http_code, hex);
 543        } else if (req->zret != Z_STREAM_END) {
 544                walker->corrupt_object_found++;
 545                ret = error("File %s (%s) corrupt", hex, req->url);
 546        } else if (hashcmp(obj_req->oid.hash, req->real_sha1)) {
 547                ret = error("File %s has bad hash", hex);
 548        } else if (req->rename < 0) {
 549                struct strbuf buf = STRBUF_INIT;
 550                sha1_file_name(the_repository, &buf, req->sha1);
 551                ret = error("unable to write sha1 filename %s", buf.buf);
 552                strbuf_release(&buf);
 553        }
 554
 555        release_http_object_request(req);
 556        release_object_request(obj_req);
 557        return ret;
 558}
 559
 560static int fetch(struct walker *walker, unsigned char *sha1)
 561{
 562        struct walker_data *data = walker->data;
 563        struct alt_base *altbase = data->alt;
 564
 565        if (!fetch_object(walker, sha1))
 566                return 0;
 567        while (altbase) {
 568                if (!http_fetch_pack(walker, altbase, sha1))
 569                        return 0;
 570                fetch_alternates(walker, data->alt->base);
 571                altbase = altbase->next;
 572        }
 573        return error("Unable to find %s under %s", sha1_to_hex(sha1),
 574                     data->alt->base);
 575}
 576
 577static int fetch_ref(struct walker *walker, struct ref *ref)
 578{
 579        struct walker_data *data = walker->data;
 580        return http_fetch_ref(data->alt->base, ref);
 581}
 582
 583static void cleanup(struct walker *walker)
 584{
 585        struct walker_data *data = walker->data;
 586        struct alt_base *alt, *alt_next;
 587
 588        if (data) {
 589                alt = data->alt;
 590                while (alt) {
 591                        alt_next = alt->next;
 592
 593                        free(alt->base);
 594                        free(alt);
 595
 596                        alt = alt_next;
 597                }
 598                free(data);
 599                walker->data = NULL;
 600        }
 601}
 602
 603struct walker *get_http_walker(const char *url)
 604{
 605        char *s;
 606        struct walker_data *data = xmalloc(sizeof(struct walker_data));
 607        struct walker *walker = xmalloc(sizeof(struct walker));
 608
 609        data->alt = xmalloc(sizeof(*data->alt));
 610        data->alt->base = xstrdup(url);
 611        for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 612                *s = 0;
 613
 614        data->alt->got_indices = 0;
 615        data->alt->packs = NULL;
 616        data->alt->next = NULL;
 617        data->got_alternates = -1;
 618
 619        walker->corrupt_object_found = 0;
 620        walker->fetch = fetch;
 621        walker->fetch_ref = fetch_ref;
 622        walker->prefetch = prefetch;
 623        walker->cleanup = cleanup;
 624        walker->data = data;
 625
 626#ifdef USE_CURL_MULTI
 627        add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 628#endif
 629
 630        return walker;
 631}