http-walker.c

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