http-walker.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "walker.h"
   4 #include "http.h"
   5 #include "list.h"
   6
   7 struct alt_base {
   8         char *base;
   9         int got_indices;
  10         struct packed_git *packs;
  11         struct alt_base *next;
  12 };
  13
  14 enum object_request_state {
  15         WAITING,
  16         ABORTED,
  17         ACTIVE,
  18         COMPLETE
  19 };
  20
  21 struct object_request {
  22         struct walker *walker;
  23         unsigned char sha1[20];
  24         struct alt_base *repo;
  25         enum object_request_state state;
  26         struct http_object_request *req;
  27         struct list_head node;
  28 };
  29
  30 struct alternates_request {
  31         struct walker *walker;
  32         const char *base;
  33         struct strbuf *url;
  34         struct strbuf *buffer;
  35         struct active_request_slot *slot;
  36         int http_specific;
  37 };
  38
  39 struct walker_data {
  40         const char *url;
  41         int got_alternates;
  42         struct alt_base *alt;
  43 };
  44
  45 static LIST_HEAD(object_queue_head);
  46
  47 static void fetch_alternates(struct walker *walker, const char *base);
  48
  49 static void process_object_response(void *callback_data);
  50
  51 static void start_object_request(struct walker *walker,
  52                                  struct object_request *obj_req)
  53 {
  54         struct active_request_slot *slot;
  55         struct http_object_request *req;
  56
  57         req = new_http_object_request(obj_req->repo->base, obj_req->sha1);
  58         if (req == NULL) {
  59                 obj_req->state = ABORTED;
  60                 return;
  61         }
  62         obj_req->req = req;
  63
  64         slot = req->slot;
  65         slot->callback_func = process_object_response;
  66         slot->callback_data = obj_req;
  67
  68         /* Try to get the request started, abort the request on error */
  69         obj_req->state = ACTIVE;
  70         if (!start_active_slot(slot)) {
  71                 obj_req->state = ABORTED;
  72                 release_http_object_request(req);
  73                 return;
  74         }
  75 }
  76
  77 static void finish_object_request(struct object_request *obj_req)
  78 {
  79         if (finish_http_object_request(obj_req->req))
  80                 return;
  81
  82         if (obj_req->req->rename == 0)
  83                 walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
  84 }
  85
  86 static void process_object_response(void *callback_data)
  87 {
  88         struct object_request *obj_req =
  89                 (struct object_request *)callback_data;
  90         struct walker *walker = obj_req->walker;
  91         struct walker_data *data = walker->data;
  92         struct alt_base *alt = data->alt;
  93
  94         process_http_object_request(obj_req->req);
  95         obj_req->state = COMPLETE;
  96
  97         /* Use alternates if necessary */
  98         if (missing_target(obj_req->req)) {
  99                 fetch_alternates(walker, alt->base);
 100                 if (obj_req->repo->next != NULL) {
 101                         obj_req->repo =
 102                                 obj_req->repo->next;
 103                         release_http_object_request(obj_req->req);
 104                         start_object_request(walker, obj_req);
 105                         return;
 106                 }
 107         }
 108
 109         finish_object_request(obj_req);
 110 }
 111
 112 static void release_object_request(struct object_request *obj_req)
 113 {
 114         if (obj_req->req !=NULL && obj_req->req->localfile != -1)
 115                 error("fd leakage in release: %d", obj_req->req->localfile);
 116
 117         list_del(&obj_req->node);
 118         free(obj_req);
 119 }
 120
 121 #ifdef USE_CURL_MULTI
 122 static int fill_active_slot(struct walker *walker)
 123 {
 124         struct object_request *obj_req;
 125         struct list_head *pos, *tmp, *head = &object_queue_head;
 126
 127         list_for_each_safe(pos, tmp, head) {
 128                 obj_req = list_entry(pos, struct object_request, node);
 129                 if (obj_req->state == WAITING) {
 130                         if (has_sha1_file(obj_req->sha1))
 131                                 obj_req->state = COMPLETE;
 132                         else {
 133                                 start_object_request(walker, obj_req);
 134                                 return 1;
 135                         }
 136                 }
 137         }
 138         return 0;
 139 }
 140 #endif
 141
 142 static void prefetch(struct walker *walker, unsigned char *sha1)
 143 {
 144         struct object_request *newreq;
 145         struct walker_data *data = walker->data;
 146
 147         newreq = xmalloc(sizeof(*newreq));
 148         newreq->walker = walker;
 149         hashcpy(newreq->sha1, sha1);
 150         newreq->repo = data->alt;
 151         newreq->state = WAITING;
 152         newreq->req = NULL;
 153
 154         http_is_verbose = walker->get_verbosely;
 155         list_add_tail(&newreq->node, &object_queue_head);
 156
 157 #ifdef USE_CURL_MULTI
 158         fill_active_slots();
 159         step_active_slots();
 160 #endif
 161 }
 162
 163 static void process_alternates_response(void *callback_data)
 164 {
 165         struct alternates_request *alt_req =
 166                 (struct alternates_request *)callback_data;
 167         struct walker *walker = alt_req->walker;
 168         struct walker_data *cdata = walker->data;
 169         struct active_request_slot *slot = alt_req->slot;
 170         struct alt_base *tail = cdata->alt;
 171         const char *base = alt_req->base;
 172         const char null_byte = '\0';
 173         char *data;
 174         int i = 0;
 175
 176         if (alt_req->http_specific) {
 177                 if (slot->curl_result != CURLE_OK ||
 178                     !alt_req->buffer->len) {
 179
 180                         /* Try reusing the slot to get non-http alternates */
 181                         alt_req->http_specific = 0;
 182                         strbuf_reset(alt_req->url);
 183                         strbuf_addf(alt_req->url, "%s/objects/info/alternates",
 184                                     base);
 185                         curl_easy_setopt(slot->curl, CURLOPT_URL,
 186                                          alt_req->url->buf);
 187                         active_requests++;
 188                         slot->in_use = 1;
 189                         if (slot->finished != NULL)
 190                                 (*slot->finished) = 0;
 191                         if (!start_active_slot(slot)) {
 192                                 cdata->got_alternates = -1;
 193                                 slot->in_use = 0;
 194                                 if (slot->finished != NULL)
 195                                         (*slot->finished) = 1;
 196                         }
 197                         return;
 198                 }
 199         } else if (slot->curl_result != CURLE_OK) {
 200                 if (!missing_target(slot)) {
 201                         cdata->got_alternates = -1;
 202                         return;
 203                 }
 204         }
 205
 206         fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
 207         alt_req->buffer->len--;
 208         data = alt_req->buffer->buf;
 209
 210         while (i < alt_req->buffer->len) {
 211                 int posn = i;
 212                 while (posn < alt_req->buffer->len && data[posn] != '\n')
 213                         posn++;
 214                 if (data[posn] == '\n') {
 215                         int okay = 0;
 216                         int serverlen = 0;
 217                         struct alt_base *newalt;
 218                         if (data[i] == '/') {
 219                                 /*
 220                                  * This counts
 221                                  * http://git.host/pub/scm/linux.git/
 222                                  * -----------here^
 223                                  * so memcpy(dst, base, serverlen) will
 224                                  * copy up to "...git.host".
 225                                  */
 226                                 const char *colon_ss = strstr(base,"://");
 227                                 if (colon_ss) {
 228                                         serverlen = (strchr(colon_ss + 3, '/')
 229                                                      - base);
 230                                         okay = 1;
 231                                 }
 232                         } else if (!memcmp(data + i, "../", 3)) {
 233                                 /*
 234                                  * Relative URL; chop the corresponding
 235                                  * number of subpath from base (and ../
 236                                  * from data), and concatenate the result.
 237                                  *
 238                                  * The code first drops ../ from data, and
 239                                  * then drops one ../ from data and one path
 240                                  * from base.  IOW, one extra ../ is dropped
 241                                  * from data than path is dropped from base.
 242                                  *
 243                                  * This is not wrong.  The alternate in
 244                                  *     http://git.host/pub/scm/linux.git/
 245                                  * to borrow from
 246                                  *     http://git.host/pub/scm/linus.git/
 247                                  * is ../../linus.git/objects/.  You need
 248                                  * two ../../ to borrow from your direct
 249                                  * neighbour.
 250                                  */
 251                                 i += 3;
 252                                 serverlen = strlen(base);
 253                                 while (i + 2 < posn &&
 254                                        !memcmp(data + i, "../", 3)) {
 255                                         do {
 256                                                 serverlen--;
 257                                         } while (serverlen &&
 258                                                  base[serverlen - 1] != '/');
 259                                         i += 3;
 260                                 }
 261                                 /* If the server got removed, give up. */
 262                                 okay = strchr(base, ':') - base + 3 <
 263                                        serverlen;
 264                         } else if (alt_req->http_specific) {
 265                                 char *colon = strchr(data + i, ':');
 266                                 char *slash = strchr(data + i, '/');
 267                                 if (colon && slash && colon < data + posn &&
 268                                     slash < data + posn && colon < slash) {
 269                                         okay = 1;
 270                                 }
 271                         }
 272                         /* skip "objects\n" at end */
 273                         if (okay) {
 274                                 struct strbuf target = STRBUF_INIT;
 275                                 strbuf_add(&target, base, serverlen);
 276                                 strbuf_add(&target, data + i, posn - i - 7);
 277                                 if (walker->get_verbosely)
 278                                         fprintf(stderr, "Also look at %s\n",
 279                                                 target.buf);
 280                                 newalt = xmalloc(sizeof(*newalt));
 281                                 newalt->next = NULL;
 282                                 newalt->base = strbuf_detach(&target, NULL);
 283                                 newalt->got_indices = 0;
 284                                 newalt->packs = NULL;
 285
 286                                 while (tail->next != NULL)
 287                                         tail = tail->next;
 288                                 tail->next = newalt;
 289                         }
 290                 }
 291                 i = posn + 1;
 292         }
 293
 294         cdata->got_alternates = 1;
 295 }
 296
 297 static void fetch_alternates(struct walker *walker, const char *base)
 298 {
 299         struct strbuf buffer = STRBUF_INIT;
 300         struct strbuf url = STRBUF_INIT;
 301         struct active_request_slot *slot;
 302         struct alternates_request alt_req;
 303         struct walker_data *cdata = walker->data;
 304
 305         /*
 306          * If another request has already started fetching alternates,
 307          * wait for them to arrive and return to processing this request's
 308          * curl message
 309          */
 310 #ifdef USE_CURL_MULTI
 311         while (cdata->got_alternates == 0) {
 312                 step_active_slots();
 313         }
 314 #endif
 315
 316         /* Nothing to do if they've already been fetched */
 317         if (cdata->got_alternates == 1)
 318                 return;
 319
 320         /* Start the fetch */
 321         cdata->got_alternates = 0;
 322
 323         if (walker->get_verbosely)
 324                 fprintf(stderr, "Getting alternates list for %s\n", base);
 325
 326         strbuf_addf(&url, "%s/objects/info/http-alternates", base);
 327
 328         /*
 329          * Use a callback to process the result, since another request
 330          * may fail and need to have alternates loaded before continuing
 331          */
 332         slot = get_active_slot();
 333         slot->callback_func = process_alternates_response;
 334         alt_req.walker = walker;
 335         slot->callback_data = &alt_req;
 336
 337         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 338         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 339         curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
 340
 341         alt_req.base = base;
 342         alt_req.url = &url;
 343         alt_req.buffer = &buffer;
 344         alt_req.http_specific = 1;
 345         alt_req.slot = slot;
 346
 347         if (start_active_slot(slot))
 348                 run_active_slot(slot);
 349         else
 350                 cdata->got_alternates = -1;
 351
 352         strbuf_release(&buffer);
 353         strbuf_release(&url);
 354 }
 355
 356 static int fetch_indices(struct walker *walker, struct alt_base *repo)
 357 {
 358         int ret;
 359
 360         if (repo->got_indices)
 361                 return 0;
 362
 363         if (walker->get_verbosely)
 364                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
 365
 366         switch (http_get_info_packs(repo->base, &repo->packs)) {
 367         case HTTP_OK:
 368         case HTTP_MISSING_TARGET:
 369                 repo->got_indices = 1;
 370                 ret = 0;
 371                 break;
 372         default:
 373                 repo->got_indices = 0;
 374                 ret = -1;
 375         }
 376
 377         return ret;
 378 }
 379
 380 static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 381 {
 382         struct packed_git *target;
 383         int ret;
 384         struct slot_results results;
 385         struct http_pack_request *preq;
 386
 387         if (fetch_indices(walker, repo))
 388                 return -1;
 389         target = find_sha1_pack(sha1, repo->packs);
 390         if (!target)
 391                 return -1;
 392
 393         if (walker->get_verbosely) {
 394                 fprintf(stderr, "Getting pack %s\n",
 395                         sha1_to_hex(target->sha1));
 396                 fprintf(stderr, " which contains %s\n",
 397                         sha1_to_hex(sha1));
 398         }
 399
 400         preq = new_http_pack_request(target, repo->base);
 401         if (preq == NULL)
 402                 goto abort;
 403         preq->lst = &repo->packs;
 404         preq->slot->results = &results;
 405
 406         if (start_active_slot(preq->slot)) {
 407                 run_active_slot(preq->slot);
 408                 if (results.curl_result != CURLE_OK) {
 409                         error("Unable to get pack file %s\n%s", preq->url,
 410                               curl_errorstr);
 411                         goto abort;
 412                 }
 413         } else {
 414                 error("Unable to start request");
 415                 goto abort;
 416         }
 417
 418         ret = finish_http_pack_request(preq);
 419         release_http_pack_request(preq);
 420         if (ret)
 421                 return ret;
 422
 423         return 0;
 424
 425 abort:
 426         return -1;
 427 }
 428
 429 static void abort_object_request(struct object_request *obj_req)
 430 {
 431         release_object_request(obj_req);
 432 }
 433
 434 static int fetch_object(struct walker *walker, unsigned char *sha1)
 435 {
 436         char *hex = sha1_to_hex(sha1);
 437         int ret = 0;
 438         struct object_request *obj_req = NULL;
 439         struct http_object_request *req;
 440         struct list_head *pos, *head = &object_queue_head;
 441
 442         list_for_each(pos, head) {
 443                 obj_req = list_entry(pos, struct object_request, node);
 444                 if (!hashcmp(obj_req->sha1, sha1))
 445                         break;
 446         }
 447         if (obj_req == NULL)
 448                 return error("Couldn't find request for %s in the queue", hex);
 449
 450         if (has_sha1_file(obj_req->sha1)) {
 451                 if (obj_req->req != NULL)
 452                         abort_http_object_request(obj_req->req);
 453                 abort_object_request(obj_req);
 454                 return 0;
 455         }
 456
 457 #ifdef USE_CURL_MULTI
 458         while (obj_req->state == WAITING)
 459                 step_active_slots();
 460 #else
 461         start_object_request(walker, obj_req);
 462 #endif
 463
 464         /*
 465          * obj_req->req might change when fetching alternates in the callback
 466          * process_object_response; therefore, the "shortcut" variable, req,
 467          * is used only after we're done with slots.
 468          */
 469         while (obj_req->state == ACTIVE)
 470                 run_active_slot(obj_req->req->slot);
 471
 472         req = obj_req->req;
 473
 474         if (req->localfile != -1) {
 475                 close(req->localfile);
 476                 req->localfile = -1;
 477         }
 478
 479         /*
 480          * we turned off CURLOPT_FAILONERROR to avoid losing a
 481          * persistent connection and got CURLE_OK.
 482          */
 483         if (req->http_code == 404 && req->curl_result == CURLE_OK &&
 484                         (starts_with(req->url, "http://") ||
 485                          starts_with(req->url, "https://")))
 486                 req->curl_result = CURLE_HTTP_RETURNED_ERROR;
 487
 488         if (obj_req->state == ABORTED) {
 489                 ret = error("Request for %s aborted", hex);
 490         } else if (req->curl_result != CURLE_OK &&
 491                    req->http_code != 416) {
 492                 if (missing_target(req))
 493                         ret = -1; /* Be silent, it is probably in a pack. */
 494                 else
 495                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 496                                     req->errorstr, req->curl_result,
 497                                     req->http_code, hex);
 498         } else if (req->zret != Z_STREAM_END) {
 499                 walker->corrupt_object_found++;
 500                 ret = error("File %s (%s) corrupt", hex, req->url);
 501         } else if (hashcmp(obj_req->sha1, req->real_sha1)) {
 502                 ret = error("File %s has bad hash", hex);
 503         } else if (req->rename < 0) {
 504                 ret = error("unable to write sha1 filename %s",
 505                             sha1_file_name(req->sha1));
 506         }
 507
 508         release_http_object_request(req);
 509         release_object_request(obj_req);
 510         return ret;
 511 }
 512
 513 static int fetch(struct walker *walker, unsigned char *sha1)
 514 {
 515         struct walker_data *data = walker->data;
 516         struct alt_base *altbase = data->alt;
 517
 518         if (!fetch_object(walker, sha1))
 519                 return 0;
 520         while (altbase) {
 521                 if (!http_fetch_pack(walker, altbase, sha1))
 522                         return 0;
 523                 fetch_alternates(walker, data->alt->base);
 524                 altbase = altbase->next;
 525         }
 526         return error("Unable to find %s under %s", sha1_to_hex(sha1),
 527                      data->alt->base);
 528 }
 529
 530 static int fetch_ref(struct walker *walker, struct ref *ref)
 531 {
 532         struct walker_data *data = walker->data;
 533         return http_fetch_ref(data->alt->base, ref);
 534 }
 535
 536 static void cleanup(struct walker *walker)
 537 {
 538         struct walker_data *data = walker->data;
 539         struct alt_base *alt, *alt_next;
 540
 541         if (data) {
 542                 alt = data->alt;
 543                 while (alt) {
 544                         alt_next = alt->next;
 545
 546                         free(alt->base);
 547                         free(alt);
 548
 549                         alt = alt_next;
 550                 }
 551                 free(data);
 552                 walker->data = NULL;
 553         }
 554 }
 555
 556 struct walker *get_http_walker(const char *url)
 557 {
 558         char *s;
 559         struct walker_data *data = xmalloc(sizeof(struct walker_data));
 560         struct walker *walker = xmalloc(sizeof(struct walker));
 561
 562         data->alt = xmalloc(sizeof(*data->alt));
 563         data->alt->base = xstrdup(url);
 564         for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 565                 *s = 0;
 566
 567         data->alt->got_indices = 0;
 568         data->alt->packs = NULL;
 569         data->alt->next = NULL;
 570         data->got_alternates = -1;
 571
 572         walker->corrupt_object_found = 0;
 573         walker->fetch = fetch;
 574         walker->fetch_ref = fetch_ref;
 575         walker->prefetch = prefetch;
 576         walker->cleanup = cleanup;
 577         walker->data = data;
 578
 579 #ifdef USE_CURL_MULTI
 580         add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 581 #endif
 582
 583         return walker;
 584 }