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 #include "packfile.h"
   8
   9 struct alt_base {
  10         char *base;
  11         int got_indices;
  12         struct packed_git *packs;
  13         struct alt_base *next;
  14 };
  15
  16 enum object_request_state {
  17         WAITING,
  18         ABORTED,
  19         ACTIVE,
  20         COMPLETE
  21 };
  22
  23 struct object_request {
  24         struct walker *walker;
  25         unsigned char sha1[20];
  26         struct alt_base *repo;
  27         enum object_request_state state;
  28         struct http_object_request *req;
  29         struct list_head node;
  30 };
  31
  32 struct alternates_request {
  33         struct walker *walker;
  34         const char *base;
  35         struct strbuf *url;
  36         struct strbuf *buffer;
  37         struct active_request_slot *slot;
  38         int http_specific;
  39 };
  40
  41 struct walker_data {
  42         const char *url;
  43         int got_alternates;
  44         struct alt_base *alt;
  45 };
  46
  47 static LIST_HEAD(object_queue_head);
  48
  49 static void fetch_alternates(struct walker *walker, const char *base);
  50
  51 static void process_object_response(void *callback_data);
  52
  53 static void start_object_request(struct walker *walker,
  54                                  struct object_request *obj_req)
  55 {
  56         struct active_request_slot *slot;
  57         struct http_object_request *req;
  58
  59         req = new_http_object_request(obj_req->repo->base, obj_req->sha1);
  60         if (req == NULL) {
  61                 obj_req->state = ABORTED;
  62                 return;
  63         }
  64         obj_req->req = req;
  65
  66         slot = req->slot;
  67         slot->callback_func = process_object_response;
  68         slot->callback_data = obj_req;
  69
  70         /* Try to get the request started, abort the request on error */
  71         obj_req->state = ACTIVE;
  72         if (!start_active_slot(slot)) {
  73                 obj_req->state = ABORTED;
  74                 release_http_object_request(req);
  75                 return;
  76         }
  77 }
  78
  79 static void finish_object_request(struct object_request *obj_req)
  80 {
  81         if (finish_http_object_request(obj_req->req))
  82                 return;
  83
  84         if (obj_req->req->rename == 0)
  85                 walker_say(obj_req->walker, "got %s\n", sha1_to_hex(obj_req->sha1));
  86 }
  87
  88 static void process_object_response(void *callback_data)
  89 {
  90         struct object_request *obj_req =
  91                 (struct object_request *)callback_data;
  92         struct walker *walker = obj_req->walker;
  93         struct walker_data *data = walker->data;
  94         struct alt_base *alt = data->alt;
  95
  96         process_http_object_request(obj_req->req);
  97         obj_req->state = COMPLETE;
  98
  99         /* Use alternates if necessary */
 100         if (missing_target(obj_req->req)) {
 101                 fetch_alternates(walker, alt->base);
 102                 if (obj_req->repo->next != NULL) {
 103                         obj_req->repo =
 104                                 obj_req->repo->next;
 105                         release_http_object_request(obj_req->req);
 106                         start_object_request(walker, obj_req);
 107                         return;
 108                 }
 109         }
 110
 111         finish_object_request(obj_req);
 112 }
 113
 114 static void release_object_request(struct object_request *obj_req)
 115 {
 116         if (obj_req->req !=NULL && obj_req->req->localfile != -1)
 117                 error("fd leakage in release: %d", obj_req->req->localfile);
 118
 119         list_del(&obj_req->node);
 120         free(obj_req);
 121 }
 122
 123 #ifdef USE_CURL_MULTI
 124 static int fill_active_slot(struct walker *walker)
 125 {
 126         struct object_request *obj_req;
 127         struct list_head *pos, *tmp, *head = &object_queue_head;
 128
 129         list_for_each_safe(pos, tmp, head) {
 130                 obj_req = list_entry(pos, struct object_request, node);
 131                 if (obj_req->state == WAITING) {
 132                         if (has_sha1_file(obj_req->sha1))
 133                                 obj_req->state = COMPLETE;
 134                         else {
 135                                 start_object_request(walker, obj_req);
 136                                 return 1;
 137                         }
 138                 }
 139         }
 140         return 0;
 141 }
 142 #endif
 143
 144 static void prefetch(struct walker *walker, unsigned char *sha1)
 145 {
 146         struct object_request *newreq;
 147         struct walker_data *data = walker->data;
 148
 149         newreq = xmalloc(sizeof(*newreq));
 150         newreq->walker = walker;
 151         hashcpy(newreq->sha1, sha1);
 152         newreq->repo = data->alt;
 153         newreq->state = WAITING;
 154         newreq->req = NULL;
 155
 156         http_is_verbose = walker->get_verbosely;
 157         list_add_tail(&newreq->node, &object_queue_head);
 158
 159 #ifdef USE_CURL_MULTI
 160         fill_active_slots();
 161         step_active_slots();
 162 #endif
 163 }
 164
 165 static int is_alternate_allowed(const char *url)
 166 {
 167         const char *protocols[] = {
 168                 "http", "https", "ftp", "ftps"
 169         };
 170         int i;
 171
 172         if (http_follow_config != HTTP_FOLLOW_ALWAYS) {
 173                 warning("alternate disabled by http.followRedirects: %s", url);
 174                 return 0;
 175         }
 176
 177         for (i = 0; i < ARRAY_SIZE(protocols); i++) {
 178                 const char *end;
 179                 if (skip_prefix(url, protocols[i], &end) &&
 180                     starts_with(end, "://"))
 181                         break;
 182         }
 183
 184         if (i >= ARRAY_SIZE(protocols)) {
 185                 warning("ignoring alternate with unknown protocol: %s", url);
 186                 return 0;
 187         }
 188         if (!is_transport_allowed(protocols[i], 0)) {
 189                 warning("ignoring alternate with restricted protocol: %s", url);
 190                 return 0;
 191         }
 192
 193         return 1;
 194 }
 195
 196 static void process_alternates_response(void *callback_data)
 197 {
 198         struct alternates_request *alt_req =
 199                 (struct alternates_request *)callback_data;
 200         struct walker *walker = alt_req->walker;
 201         struct walker_data *cdata = walker->data;
 202         struct active_request_slot *slot = alt_req->slot;
 203         struct alt_base *tail = cdata->alt;
 204         const char *base = alt_req->base;
 205         const char null_byte = '\0';
 206         char *data;
 207         int i = 0;
 208
 209         if (alt_req->http_specific) {
 210                 if (slot->curl_result != CURLE_OK ||
 211                     !alt_req->buffer->len) {
 212
 213                         /* Try reusing the slot to get non-http alternates */
 214                         alt_req->http_specific = 0;
 215                         strbuf_reset(alt_req->url);
 216                         strbuf_addf(alt_req->url, "%s/objects/info/alternates",
 217                                     base);
 218                         curl_easy_setopt(slot->curl, CURLOPT_URL,
 219                                          alt_req->url->buf);
 220                         active_requests++;
 221                         slot->in_use = 1;
 222                         if (slot->finished != NULL)
 223                                 (*slot->finished) = 0;
 224                         if (!start_active_slot(slot)) {
 225                                 cdata->got_alternates = -1;
 226                                 slot->in_use = 0;
 227                                 if (slot->finished != NULL)
 228                                         (*slot->finished) = 1;
 229                         }
 230                         return;
 231                 }
 232         } else if (slot->curl_result != CURLE_OK) {
 233                 if (!missing_target(slot)) {
 234                         cdata->got_alternates = -1;
 235                         return;
 236                 }
 237         }
 238
 239         fwrite_buffer((char *)&null_byte, 1, 1, alt_req->buffer);
 240         alt_req->buffer->len--;
 241         data = alt_req->buffer->buf;
 242
 243         while (i < alt_req->buffer->len) {
 244                 int posn = i;
 245                 while (posn < alt_req->buffer->len && data[posn] != '\n')
 246                         posn++;
 247                 if (data[posn] == '\n') {
 248                         int okay = 0;
 249                         int serverlen = 0;
 250                         struct alt_base *newalt;
 251                         if (data[i] == '/') {
 252                                 /*
 253                                  * This counts
 254                                  * http://git.host/pub/scm/linux.git/
 255                                  * -----------here^
 256                                  * so memcpy(dst, base, serverlen) will
 257                                  * copy up to "...git.host".
 258                                  */
 259                                 const char *colon_ss = strstr(base,"://");
 260                                 if (colon_ss) {
 261                                         serverlen = (strchr(colon_ss + 3, '/')
 262                                                      - base);
 263                                         okay = 1;
 264                                 }
 265                         } else if (!memcmp(data + i, "../", 3)) {
 266                                 /*
 267                                  * Relative URL; chop the corresponding
 268                                  * number of subpath from base (and ../
 269                                  * from data), and concatenate the result.
 270                                  *
 271                                  * The code first drops ../ from data, and
 272                                  * then drops one ../ from data and one path
 273                                  * from base.  IOW, one extra ../ is dropped
 274                                  * from data than path is dropped from base.
 275                                  *
 276                                  * This is not wrong.  The alternate in
 277                                  *     http://git.host/pub/scm/linux.git/
 278                                  * to borrow from
 279                                  *     http://git.host/pub/scm/linus.git/
 280                                  * is ../../linus.git/objects/.  You need
 281                                  * two ../../ to borrow from your direct
 282                                  * neighbour.
 283                                  */
 284                                 i += 3;
 285                                 serverlen = strlen(base);
 286                                 while (i + 2 < posn &&
 287                                        !memcmp(data + i, "../", 3)) {
 288                                         do {
 289                                                 serverlen--;
 290                                         } while (serverlen &&
 291                                                  base[serverlen - 1] != '/');
 292                                         i += 3;
 293                                 }
 294                                 /* If the server got removed, give up. */
 295                                 okay = strchr(base, ':') - base + 3 <
 296                                        serverlen;
 297                         } else if (alt_req->http_specific) {
 298                                 char *colon = strchr(data + i, ':');
 299                                 char *slash = strchr(data + i, '/');
 300                                 if (colon && slash && colon < data + posn &&
 301                                     slash < data + posn && colon < slash) {
 302                                         okay = 1;
 303                                 }
 304                         }
 305                         if (okay) {
 306                                 struct strbuf target = STRBUF_INIT;
 307                                 strbuf_add(&target, base, serverlen);
 308                                 strbuf_add(&target, data + i, posn - i);
 309                                 if (!strbuf_strip_suffix(&target, "objects")) {
 310                                         warning("ignoring alternate that does"
 311                                                 " not end in 'objects': %s",
 312                                                 target.buf);
 313                                         strbuf_release(&target);
 314                                 } else if (is_alternate_allowed(target.buf)) {
 315                                         warning("adding alternate object store: %s",
 316                                                 target.buf);
 317                                         newalt = xmalloc(sizeof(*newalt));
 318                                         newalt->next = NULL;
 319                                         newalt->base = strbuf_detach(&target, NULL);
 320                                         newalt->got_indices = 0;
 321                                         newalt->packs = NULL;
 322
 323                                         while (tail->next != NULL)
 324                                                 tail = tail->next;
 325                                         tail->next = newalt;
 326                                 } else {
 327                                         strbuf_release(&target);
 328                                 }
 329                         }
 330                 }
 331                 i = posn + 1;
 332         }
 333
 334         cdata->got_alternates = 1;
 335 }
 336
 337 static void fetch_alternates(struct walker *walker, const char *base)
 338 {
 339         struct strbuf buffer = STRBUF_INIT;
 340         struct strbuf url = STRBUF_INIT;
 341         struct active_request_slot *slot;
 342         struct alternates_request alt_req;
 343         struct walker_data *cdata = walker->data;
 344
 345         /*
 346          * If another request has already started fetching alternates,
 347          * wait for them to arrive and return to processing this request's
 348          * curl message
 349          */
 350 #ifdef USE_CURL_MULTI
 351         while (cdata->got_alternates == 0) {
 352                 step_active_slots();
 353         }
 354 #endif
 355
 356         /* Nothing to do if they've already been fetched */
 357         if (cdata->got_alternates == 1)
 358                 return;
 359
 360         /* Start the fetch */
 361         cdata->got_alternates = 0;
 362
 363         if (walker->get_verbosely)
 364                 fprintf(stderr, "Getting alternates list for %s\n", base);
 365
 366         strbuf_addf(&url, "%s/objects/info/http-alternates", base);
 367
 368         /*
 369          * Use a callback to process the result, since another request
 370          * may fail and need to have alternates loaded before continuing
 371          */
 372         slot = get_active_slot();
 373         slot->callback_func = process_alternates_response;
 374         alt_req.walker = walker;
 375         slot->callback_data = &alt_req;
 376
 377         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 378         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 379         curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
 380
 381         alt_req.base = base;
 382         alt_req.url = &url;
 383         alt_req.buffer = &buffer;
 384         alt_req.http_specific = 1;
 385         alt_req.slot = slot;
 386
 387         if (start_active_slot(slot))
 388                 run_active_slot(slot);
 389         else
 390                 cdata->got_alternates = -1;
 391
 392         strbuf_release(&buffer);
 393         strbuf_release(&url);
 394 }
 395
 396 static int fetch_indices(struct walker *walker, struct alt_base *repo)
 397 {
 398         int ret;
 399
 400         if (repo->got_indices)
 401                 return 0;
 402
 403         if (walker->get_verbosely)
 404                 fprintf(stderr, "Getting pack list for %s\n", repo->base);
 405
 406         switch (http_get_info_packs(repo->base, &repo->packs)) {
 407         case HTTP_OK:
 408         case HTTP_MISSING_TARGET:
 409                 repo->got_indices = 1;
 410                 ret = 0;
 411                 break;
 412         default:
 413                 repo->got_indices = 0;
 414                 ret = -1;
 415         }
 416
 417         return ret;
 418 }
 419
 420 static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigned char *sha1)
 421 {
 422         struct packed_git *target;
 423         int ret;
 424         struct slot_results results;
 425         struct http_pack_request *preq;
 426
 427         if (fetch_indices(walker, repo))
 428                 return -1;
 429         target = find_sha1_pack(sha1, repo->packs);
 430         if (!target)
 431                 return -1;
 432
 433         if (walker->get_verbosely) {
 434                 fprintf(stderr, "Getting pack %s\n",
 435                         sha1_to_hex(target->sha1));
 436                 fprintf(stderr, " which contains %s\n",
 437                         sha1_to_hex(sha1));
 438         }
 439
 440         preq = new_http_pack_request(target, repo->base);
 441         if (preq == NULL)
 442                 goto abort;
 443         preq->lst = &repo->packs;
 444         preq->slot->results = &results;
 445
 446         if (start_active_slot(preq->slot)) {
 447                 run_active_slot(preq->slot);
 448                 if (results.curl_result != CURLE_OK) {
 449                         error("Unable to get pack file %s\n%s", preq->url,
 450                               curl_errorstr);
 451                         goto abort;
 452                 }
 453         } else {
 454                 error("Unable to start request");
 455                 goto abort;
 456         }
 457
 458         ret = finish_http_pack_request(preq);
 459         release_http_pack_request(preq);
 460         if (ret)
 461                 return ret;
 462
 463         return 0;
 464
 465 abort:
 466         return -1;
 467 }
 468
 469 static void abort_object_request(struct object_request *obj_req)
 470 {
 471         release_object_request(obj_req);
 472 }
 473
 474 static int fetch_object(struct walker *walker, unsigned char *sha1)
 475 {
 476         char *hex = sha1_to_hex(sha1);
 477         int ret = 0;
 478         struct object_request *obj_req = NULL;
 479         struct http_object_request *req;
 480         struct list_head *pos, *head = &object_queue_head;
 481
 482         list_for_each(pos, head) {
 483                 obj_req = list_entry(pos, struct object_request, node);
 484                 if (!hashcmp(obj_req->sha1, sha1))
 485                         break;
 486         }
 487         if (obj_req == NULL)
 488                 return error("Couldn't find request for %s in the queue", hex);
 489
 490         if (has_sha1_file(obj_req->sha1)) {
 491                 if (obj_req->req != NULL)
 492                         abort_http_object_request(obj_req->req);
 493                 abort_object_request(obj_req);
 494                 return 0;
 495         }
 496
 497 #ifdef USE_CURL_MULTI
 498         while (obj_req->state == WAITING)
 499                 step_active_slots();
 500 #else
 501         start_object_request(walker, obj_req);
 502 #endif
 503
 504         /*
 505          * obj_req->req might change when fetching alternates in the callback
 506          * process_object_response; therefore, the "shortcut" variable, req,
 507          * is used only after we're done with slots.
 508          */
 509         while (obj_req->state == ACTIVE)
 510                 run_active_slot(obj_req->req->slot);
 511
 512         req = obj_req->req;
 513
 514         if (req->localfile != -1) {
 515                 close(req->localfile);
 516                 req->localfile = -1;
 517         }
 518
 519         /*
 520          * we turned off CURLOPT_FAILONERROR to avoid losing a
 521          * persistent connection and got CURLE_OK.
 522          */
 523         if (req->http_code >= 300 && req->curl_result == CURLE_OK &&
 524                         (starts_with(req->url, "http://") ||
 525                          starts_with(req->url, "https://"))) {
 526                 req->curl_result = CURLE_HTTP_RETURNED_ERROR;
 527                 xsnprintf(req->errorstr, sizeof(req->errorstr),
 528                           "HTTP request failed");
 529         }
 530
 531         if (obj_req->state == ABORTED) {
 532                 ret = error("Request for %s aborted", hex);
 533         } else if (req->curl_result != CURLE_OK &&
 534                    req->http_code != 416) {
 535                 if (missing_target(req))
 536                         ret = -1; /* Be silent, it is probably in a pack. */
 537                 else
 538                         ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
 539                                     req->errorstr, req->curl_result,
 540                                     req->http_code, hex);
 541         } else if (req->zret != Z_STREAM_END) {
 542                 walker->corrupt_object_found++;
 543                 ret = error("File %s (%s) corrupt", hex, req->url);
 544         } else if (hashcmp(obj_req->sha1, req->real_sha1)) {
 545                 ret = error("File %s has bad hash", hex);
 546         } else if (req->rename < 0) {
 547                 struct strbuf buf = STRBUF_INIT;
 548                 sha1_file_name(&buf, req->sha1);
 549                 ret = error("unable to write sha1 filename %s", buf.buf);
 550                 strbuf_release(&buf);
 551         }
 552
 553         release_http_object_request(req);
 554         release_object_request(obj_req);
 555         return ret;
 556 }
 557
 558 static int fetch(struct walker *walker, unsigned char *sha1)
 559 {
 560         struct walker_data *data = walker->data;
 561         struct alt_base *altbase = data->alt;
 562
 563         if (!fetch_object(walker, sha1))
 564                 return 0;
 565         while (altbase) {
 566                 if (!http_fetch_pack(walker, altbase, sha1))
 567                         return 0;
 568                 fetch_alternates(walker, data->alt->base);
 569                 altbase = altbase->next;
 570         }
 571         return error("Unable to find %s under %s", sha1_to_hex(sha1),
 572                      data->alt->base);
 573 }
 574
 575 static int fetch_ref(struct walker *walker, struct ref *ref)
 576 {
 577         struct walker_data *data = walker->data;
 578         return http_fetch_ref(data->alt->base, ref);
 579 }
 580
 581 static void cleanup(struct walker *walker)
 582 {
 583         struct walker_data *data = walker->data;
 584         struct alt_base *alt, *alt_next;
 585
 586         if (data) {
 587                 alt = data->alt;
 588                 while (alt) {
 589                         alt_next = alt->next;
 590
 591                         free(alt->base);
 592                         free(alt);
 593
 594                         alt = alt_next;
 595                 }
 596                 free(data);
 597                 walker->data = NULL;
 598         }
 599 }
 600
 601 struct walker *get_http_walker(const char *url)
 602 {
 603         char *s;
 604         struct walker_data *data = xmalloc(sizeof(struct walker_data));
 605         struct walker *walker = xmalloc(sizeof(struct walker));
 606
 607         data->alt = xmalloc(sizeof(*data->alt));
 608         data->alt->base = xstrdup(url);
 609         for (s = data->alt->base + strlen(data->alt->base) - 1; *s == '/'; --s)
 610                 *s = 0;
 611
 612         data->alt->got_indices = 0;
 613         data->alt->packs = NULL;
 614         data->alt->next = NULL;
 615         data->got_alternates = -1;
 616
 617         walker->corrupt_object_found = 0;
 618         walker->fetch = fetch;
 619         walker->fetch_ref = fetch_ref;
 620         walker->prefetch = prefetch;
 621         walker->cleanup = cleanup;
 622         walker->data = data;
 623
 624 #ifdef USE_CURL_MULTI
 625         add_fill_function(walker, (int (*)(void *)) fill_active_slot);
 626 #endif
 627
 628         return walker;
 629 }