http-walker.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "walker.h"
   4 #include "http.h"
   5
   6 struct alt_base {
   7         char *base;
   8         int got_indices;
   9         struct packed_git *packs;
  10         struct alt_base *next;
  11 };
  12
  13 enum object_request_state {
  14         WAITING,
  15         ABORTED,
  16         ACTIVE,
  17         COMPLETE
  18 };
  19
  20 struct object_request {
  21         struct walker *walker;
  22         unsigned char sha1[20];
  23         struct alt_base *repo;
  24         enum object_request_state state;
  25         struct http_object_request *req;
  26         struct object_request *next;
  27 };
  28
  29 struct alternates_request {
  30         struct walker *walker;
  31         const char *base;
  32         char *url;
  33         struct strbuf *buffer;
  34         struct active_request_slot *slot;
  35         int http_specific;
  36 };
  37
  38 struct walker_data {
  39         const char *url;
  40         int got_alternates;
  41         struct alt_base *alt;
  42 };
  43
  44 static struct object_request *object_queue_head;
  45
  46 static void fetch_alternates(struct walker *walker, const char *base);
  47
  48 static void process_object_response(void *callback_data);
  49
  50 static void start_object_request(struct walker *walker,
  51                                  struct object_request *obj_req)
  52 {
  53         struct active_request_slot *slot;
  54         struct http_object_request *req;
  55
  56         req = new_http_object_request(obj_req->repo->base, obj_req->sha1);
  57         if (req == NULL) {
  58                 obj_req->state = ABORTED;
  59                 return;
  60         }
  61         obj_req->req = req;
  62
  63         slot = req->slot;
  64         slot->callback_func = process_object_response;
  65         slot->callback_data = obj_req;
  66
  67         /* Try to get the request started, abort the request on error */
  68         obj_req->state = ACTIVE;
  69         if (!start_active_slot(slot)) {
  70                 obj_req->state = ABORTED;
  71                 release_http_object_request(req);
  72                 return;
  73         }
  74 }
  75
  76 static void finish_object_request(struct object_request *obj_req)
  77 {
  78         if (finish_http_object_request(obj_req->req))
  79                 return;
  80
  81         if (obj_req->req->rename == 0)
  82                 walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
  83 }
  84
  85 static void process_object_response(void *callback_data)
  86 {
  87         struct object_request *obj_req =
  88                 (struct object_request *)callback_data;
  89         struct walker *walker = obj_req->walker;
  90         struct walker_data *data = walker->data;
  91         struct alt_base *alt = data->alt;
  92
  93         process_http_object_request(obj_req->req);
  94         obj_req->state = COMPLETE;
  95
  96         /* Use alternates if necessary */
  97         if (missing_target(obj_req->req)) {
  98                 fetch_alternates(walker, alt->base);
  99                 if (obj_req->repo->next != NULL) {
 100                         obj_req->repo =
 101                                 obj_req->repo->next;
 102                         release_http_object_request(obj_req->req);
 103                         start_object_request(walker, obj_req);
 104                         return;
 105                 }
 106         }
 107
 108         finish_object_request(obj_req);
 109 }
 110
 111 static void release_object_request(struct object_request *obj_req)
 112 {
 113         struct object_request *entry = object_queue_head;
 114
 115         if (obj_req->req !=NULL && obj_req->req->localfile != -1)
 116                 error("fd leakage in release: %d", obj_req->req->localfile);
 117         if (obj_req == object_queue_head) {
 118                 object_queue_head = obj_req->next;
 119         } else {
 120                 while (entry->next != NULL && entry->next != obj_req)
 121                         entry = entry->next;
 122                 if (entry->next == obj_req)
 123                         entry->next = entry->next->next;
 124         }
 125
 126         free(obj_req);
 127 }
 128
 129 #ifdef USE_CURL_MULTI
 130 static int fill_active_slot(struct walker *walker)
 131 {
 132         struct object_request *obj_req;
 133
 134         for (obj_req = object_queue_head; obj_req; obj_req = obj_req->next) {
 135                 if (obj_req->state == WAITING) {
 136                         if (has_sha1_file(obj_req->sha1))
 137                                 obj_req->state = COMPLETE;
 138                         else {
 139                                 start_object_request(walker, obj_req);
 140                                 return 1;
 141                         }
 142                 }
 143         }
 144         return 0;
 145 }
 146 #endif
 147
 148 static void prefetch(struct walker *walker, unsigned char *sha1)
 149 {
 150         struct object_request *newreq;
 151         struct object_request *tail;
 152         struct walker_data *data = walker->data;
 153
 154         newreq = xmalloc(sizeof(*newreq));
 155         newreq->walker = walker;
 156         hashcpy(newreq->sha1, sha1);
 157         newreq->repo = data->alt;
 158         newreq->state = WAITING;
 159         newreq->req = NULL;
 160         newreq->next = NULL;
 161
 162         http_is_verbose = walker->get_verbosely;
 163
 164         if (object_queue_head == NULL) {
 165                 object_queue_head = newreq;
 166         } else {
 167                 tail = object_queue_head;
 168                 while (tail->next != NULL)
 169                         tail = tail->next;
 170                 tail->next = newreq;
 171         }
 172
 173 #ifdef USE_CURL_MULTI
 174         fill_active_slots();
 175         step_active_slots();
 176 #endif
 177 }
 178
 179 static void process_alternates_response(void *callback_data)
 180 {
 181         struct alternates_request *alt_req =
 182                 (struct alternates_request *)callback_data;
 183         struct walker *walker = alt_req->walker;
 184         struct walker_data *cdata = walker->data;
 185         struct active_request_slot *slot = alt_req->slot;
 186         struct alt_base *tail = cdata->alt;
 187         const char *base = alt_req->base;
 188         const char null_byte = '\0';
 189         char *data;
 190         int i = 0;
 191
 192         if (alt_req->http_specific) {
 193                 if (slot->curl_result != CURLE_OK ||
 194                     !alt_req->buffer->len) {
 195
 196                         /* Try reusing the slot to get non-http alternates */
 197                         alt_req->http_specific = 0;
 198                         sprintf(alt_req->url, "%s/objects/info/alternates",
 199                                 base);
 200                         curl_easy_setopt(slot->curl, CURLOPT_URL,
 201                                          alt_req->url);
 202                         active_requests++;
 203                         slot->in_use = 1;
 204                         if (slot->finished != NULL)
 205                                 (*slot->finished) = 0;
 206                         if (!start_active_slot(slot)) {
 207                                 cdata->got_alternates = -1;
 208                                 slot->in_use = 0;
 209                                 if (slot->finished != NULL)
 210                                         (*slot->finished) = 1;
 211                         }
 212                         return;
 213                 }
 214         } else if (slot->curl_result != CURLE_OK) {
 215                 if (!missing_target(slot)) {
 216                         cdata->got_alternates = -1;
 217                         return;
 218                 }
 219         }
 220
 221         fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
 222         alt_req->buffer->len--;
 223         data = alt_req->buffer->buf;
 224
 225         while (i < alt_req->buffer->len) {
 226                 int posn = i;
 227                 while (posn < alt_req->buffer->len && data[posn] != '\n')
 228                         posn++;
 229                 if (data[posn] == '\n') {
 230                         int okay = 0;
 231                         int serverlen = 0;
 232                         struct alt_base *newalt;
 233                         char *target = NULL;
 234                         if (data[i] == '/') {
 235                                 /*
 236                                  * This counts
 237                                  * http://git.host/pub/scm/linux.git/
 238                                  * -----------here^
 239                                  * so memcpy(dst, base, serverlen) will
 240                                  * copy up to "...git.host".
 241                                  */
 242                                 const char *colon_ss = strstr(base,"://");
 243                                 if (colon_ss) {
 244                                         serverlen = (strchr(colon_ss + 3, '/')
 245                                                      - base);
 246                                         okay = 1;
 247                                 }
 248                         } else if (!memcmp(data + i, "../", 3)) {
 249                                 /*
 250                                  * Relative URL; chop the corresponding
 251                                  * number of subpath from base (and ../
 252                                  * from data), and concatenate the result.
 253                                  *
 254                                  * The code first drops ../ from data, and
 255                                  * then drops one ../ from data and one path
 256                                  * from base.  IOW, one extra ../ is dropped
 257                                  * from data than path is dropped from base.
 258                                  *
 259                                  * This is not wrong.  The alternate in
 260                                  *     http://git.host/pub/scm/linux.git/
 261                                  * to borrow from
 262                                  *     http://git.host/pub/scm/linus.git/
 263                                  * is ../../linus.git/objects/.  You need
 264                                  * two ../../ to borrow from your direct
 265                                  * neighbour.
 266                                  */
 267                                 i += 3;
 268                                 serverlen = strlen(base);
 269                                 while (i + 2 < posn &&
 270                                        !memcmp(data + i, "../", 3)) {
 271                                         do {
 272                                                 serverlen--;
 273                                         } while (serverlen &&
 274                                                  base[serverlen - 1] != '/');
 275                                         i += 3;
 276                                 }
 277                                 /* If the server got removed, give up. */
 278                                 okay = strchr(base, ':') - base + 3 <
 279                                        serverlen;
 280                         } else if (alt_req->http_specific) {
 281                                 char *colon = strchr(data + i, ':');
 282                                 char *slash = strchr(data + i, '/');
 283                                 if (colon && slash && colon < data + posn &&
 284                                     slash < data + posn && colon < slash) {
 285                                         okay = 1;
 286                                 }
 287                         }
 288                         /* skip "objects\n" at end */
 289                         if (okay) {
 290                                 target = xmalloc(serverlen + posn - i - 6);
 291                                 memcpy(target, base, serverlen);
 292                                 memcpy(target + serverlen, data + i,
 293                                        posn - i - 7);
 294                                 target[serverlen + posn - i - 7] = 0;
 295                                 if (walker->get_verbosely)
 296                                         fprintf(stderr,
 297                                                 "Also look at %s\n", target);
 298                                 newalt = xmalloc(sizeof(*newalt));
 299                                 newalt->next = NULL;
 300                                 newalt->base = target;
 301                                 newalt->got_indices = 0;
 302                                 newalt->packs = NULL;
 303
 304                                 while (tail->next != NULL)
 305                                         tail = tail->next;
 306                                 tail->next = newalt;
 307                         }
 308                 }
 309                 i = posn + 1;
 310         }
 311
 312         cdata->got_alternates = 1;
 313 }
 314
 315 static void fetch_alternates(struct walker *walker, const char *base)
 316 {
 317         struct strbuf buffer = STRBUF_INIT;
 318         char *url;
 319         struct active_request_slot *slot;
 320         struct alternates_request alt_req;
 321         struct walker_data *cdata = walker->data;
 322
 323         /*
 324          * If another request has already started fetching alternates,
 325          * wait for them to arrive and return to processing this request's
 326          * curl message
 327          */
 328 #ifdef USE_CURL_MULTI
 329         while (cdata->got_alternates == 0) {
 330                 step_active_slots();
 331         }
 332 #endif
 333
 334         /* Nothing to do if they've already been fetched */
 335         if (cdata->got_alternates == 1)
 336                 return;
 337
 338         /* Start the fetch */
 339         cdata->got_alternates = 0;
 340
 341         if (walker->get_verbosely)
 342                 fprintf(stderr, "Getting alternates list for %s\n", base);
 343
 344         url = xmalloc(strlen(base) + 31);
 345         sprintf(url, "%s/objects/info/http-alternates", base);
 346
 347         /*
 348          * Use a callback to process the result, since another request
 349          * may fail and need to have alternates loaded before continuing
 350          */
 351         slot = get_active_slot();
 352         slot->callback_func = process_alternates_response;
 353         alt_req.walker = walker;
 354         slot->callback_data = &alt_req;
 355
 356         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 357         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 358         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 359
 360         alt_req.base = base;
 361         alt_req.url = url;
 362         alt_req.buffer = &buffer;
 363         alt_req.http_specific = 1;
 364         alt_req.slot = slot;
 365
 366         if (start_active_slot(slot))
 367                 run_active_slot(slot);
 368         else
 369                 cdata->got_alternates = -1;
 370
 371         strbuf_release(&buffer);
 372         free(url);
 373 }
 374
 375 static int fetch_indices(struct walker *walker, struct alt_base *repo)
 376 {
 377         int ret;
 378
 379         if (repo->got_indices)
 380                 return 0;
 381
 382         if (walker->get_verbosely)
 383                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
 384
 385         switch (http_get_info_packs(repo->base, &repo->packs)) {
 386         case HTTP_OK:
 387         case HTTP_MISSING_TARGET:
 388                 repo->got_indices = 1;
 389                 ret = 0;
 390                 break;
 391         default:
 392                 repo->got_indices = 0;
 393                 ret = -1;
 394         }
 395
 396         return ret;
 397 }
 398
 399 static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 400 {
 401         struct packed_git *target;
 402         int ret;
 403         struct slot_results results;
 404         struct http_pack_request *preq;
 405
 406         if (fetch_indices(walker, repo))
 407                 return -1;
 408         target = find_sha1_pack(sha1, repo->packs);
 409         if (!target)
 410                 return -1;
 411
 412         if (walker->get_verbosely) {
 413                 fprintf(stderr, "Getting pack %s\n",
 414                         sha1_to_hex(target->sha1));
 415                 fprintf(stderr, " which contains %s\n",
 416                         sha1_to_hex(sha1));
 417         }
 418
 419         preq = new_http_pack_request(target, repo->base);
 420         if (preq == NULL)
 421                 goto abort;
 422         preq->lst = &repo->packs;
 423         preq->slot->results = &results;
 424
 425         if (start_active_slot(preq->slot)) {
 426                 run_active_slot(preq->slot);
 427                 if (results.curl_result != CURLE_OK) {
 428                         error("Unable to get pack file %s\n%s", preq->url,
 429                               curl_errorstr);
 430                         goto abort;
 431                 }
 432         } else {
 433                 error("Unable to start request");
 434                 goto abort;
 435         }
 436
 437         ret = finish_http_pack_request(preq);
 438         release_http_pack_request(preq);
 439         if (ret)
 440                 return ret;
 441
 442         return 0;
 443
 444 abort:
 445         return -1;
 446 }
 447
 448 static void abort_object_request(struct object_request *obj_req)
 449 {
 450         release_object_request(obj_req);
 451 }
 452
 453 static int fetch_object(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 454 {
 455         char *hex = sha1_to_hex(sha1);
 456         int ret = 0;
 457         struct object_request *obj_req = object_queue_head;
 458         struct http_object_request *req;
 459
 460         while (obj_req != NULL && hashcmp(obj_req->sha1, sha1))
 461                 obj_req = obj_req->next;
 462         if (obj_req == NULL)
 463                 return error("Couldn't find request for %s in the queue", hex);
 464
 465         if (has_sha1_file(obj_req->sha1)) {
 466                 if (obj_req->req != NULL)
 467                         abort_http_object_request(obj_req->req);
 468                 abort_object_request(obj_req);
 469                 return 0;
 470         }
 471
 472 #ifdef USE_CURL_MULTI
 473         while (obj_req->state == WAITING)
 474                 step_active_slots();
 475 #else
 476         start_object_request(walker, obj_req);
 477 #endif
 478
 479         /*
 480          * obj_req->req might change when fetching alternates in the callback
 481          * process_object_response; therefore, the "shortcut" variable, req,
 482          * is used only after we're done with slots.
 483          */
 484         while (obj_req->state == ACTIVE)
 485                 run_active_slot(obj_req->req->slot);
 486
 487         req = obj_req->req;
 488
 489         if (req->localfile != -1) {
 490                 close(req->localfile);
 491                 req->localfile = -1;
 492         }
 493
 494         if (obj_req->state == ABORTED) {
 495                 ret = error("Request for %s aborted", hex);
 496         } else if (req->curl_result != CURLE_OK &&
 497                    req->http_code != 416) {
 498                 if (missing_target(req))
 499                         ret = -1; /* Be silent, it is probably in a pack. */
 500                 else
 501                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 502                                     req->errorstr, req->curl_result,
 503                                     req->http_code, hex);
 504         } else if (req->zret != Z_STREAM_END) {
 505                 walker->corrupt_object_found++;
 506                 ret = error("File %s (%s) corrupt", hex, req->url);
 507         } else if (hashcmp(obj_req->sha1, req->real_sha1)) {
 508                 ret = error("File %s has bad hash", hex);
 509         } else if (req->rename < 0) {
 510                 ret = error("unable to write sha1 filename %s",
 511                             sha1_file_name(req->sha1));
 512         }
 513
 514         release_http_object_request(req);
 515         release_object_request(obj_req);
 516         return ret;
 517 }
 518
 519 static int fetch(struct walker *walker, unsigned char *sha1)
 520 {
 521         struct walker_data *data = walker->data;
 522         struct alt_base *altbase = data->alt;
 523
 524         if (!fetch_object(walker, altbase, sha1))
 525                 return 0;
 526         while (altbase) {
 527                 if (!http_fetch_pack(walker, altbase, sha1))
 528                         return 0;
 529                 fetch_alternates(walker, data->alt->base);
 530                 altbase = altbase->next;
 531         }
 532         return error("Unable to find %s under %s", sha1_to_hex(sha1),
 533                      data->alt->base);
 534 }
 535
 536 static int fetch_ref(struct walker *walker, struct ref *ref)
 537 {
 538         struct walker_data *data = walker->data;
 539         return http_fetch_ref(data->alt->base, ref);
 540 }
 541
 542 static void cleanup(struct walker *walker)
 543 {
 544         struct walker_data *data = walker->data;
 545         struct alt_base *alt, *alt_next;
 546
 547         if (data) {
 548                 alt = data->alt;
 549                 while (alt) {
 550                         alt_next = alt->next;
 551
 552                         free(alt->base);
 553                         free(alt);
 554
 555                         alt = alt_next;
 556                 }
 557                 free(data);
 558                 walker->data = NULL;
 559         }
 560 }
 561
 562 struct walker *get_http_walker(const char *url)
 563 {
 564         char *s;
 565         struct walker_data *data = xmalloc(sizeof(struct walker_data));
 566         struct walker *walker = xmalloc(sizeof(struct walker));
 567
 568         data->alt = xmalloc(sizeof(*data->alt));
 569         data->alt->base = xmalloc(strlen(url) + 1);
 570         strcpy(data->alt->base, url);
 571         for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 572                 *s = 0;
 573
 574         data->alt->got_indices = 0;
 575         data->alt->packs = NULL;
 576         data->alt->next = NULL;
 577         data->got_alternates = -1;
 578
 579         walker->corrupt_object_found = 0;
 580         walker->fetch = fetch;
 581         walker->fetch_ref = fetch_ref;
 582         walker->prefetch = prefetch;
 583         walker->cleanup = cleanup;
 584         walker->data = data;
 585
 586 #ifdef USE_CURL_MULTI
 587         add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 588 #endif
 589
 590         return walker;
 591 }