http-walker.c

   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
  11 struct alt_base {
  12         char *base;
  13         int got_indices;
  14         struct packed_git *packs;
  15         struct alt_base *next;
  16 };
  17
  18 enum object_request_state {
  19         WAITING,
  20         ABORTED,
  21         ACTIVE,
  22         COMPLETE
  23 };
  24
  25 struct 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
  34 struct 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
  43 struct walker_data {
  44         const char *url;
  45         int got_alternates;
  46         struct alt_base *alt;
  47 };
  48
  49 static LIST_HEAD(object_queue_head);
  50
  51 static void fetch_alternates(struct walker *walker, const char *base);
  52
  53 static void process_object_response(void *callback_data);
  54
  55 static 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
  81 static 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
  90 static 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
 116 static 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
 126 static 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
 146 static 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
 167 static 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
 198 static 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
 339 static 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
 398 static 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
 422 static 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
 467 abort:
 468         return -1;
 469 }
 470
 471 static void abort_object_request(struct object_request *obj_req)
 472 {
 473         release_object_request(obj_req);
 474 }
 475
 476 static 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 (hasheq(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 (!hasheq(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
 560 static 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
 577 static 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
 583 static 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
 603 struct 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 }