http-walker.c

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