builtin-fsck.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "commit.h"
   4 #include "tree.h"
   5 #include "blob.h"
   6 #include "tag.h"
   7 #include "refs.h"
   8 #include "pack.h"
   9 #include "cache-tree.h"
  10 #include "tree-walk.h"
  11
  12 #define REACHABLE 0x0001
  13 #define SEEN      0x0002
  14
  15 static int show_root;
  16 static int show_tags;
  17 static int show_unreachable;
  18 static int include_reflogs = 1;
  19 static int check_full;
  20 static int check_strict;
  21 static int keep_cache_objects;
  22 static unsigned char head_sha1[20];
  23 static int errors_found;
  24 static int write_lost_and_found;
  25 static int verbose;
  26 #define ERROR_OBJECT 01
  27 #define ERROR_REACHABLE 02
  28
  29 #ifdef NO_D_INO_IN_DIRENT
  30 #define SORT_DIRENT 0
  31 #define DIRENT_SORT_HINT(de) 0
  32 #else
  33 #define SORT_DIRENT 1
  34 #define DIRENT_SORT_HINT(de) ((de)->d_ino)
  35 #endif
  36
  37 static void objreport(struct object *obj, const char *severity,
  38                       const char *err, va_list params)
  39 {
  40         fprintf(stderr, "%s in %s %s: ",
  41                 severity, typename(obj->type), sha1_to_hex(obj->sha1));
  42         vfprintf(stderr, err, params);
  43         fputs("\n", stderr);
  44 }
  45
  46 static int objerror(struct object *obj, const char *err, ...)
  47 {
  48         va_list params;
  49         va_start(params, err);
  50         errors_found |= ERROR_OBJECT;
  51         objreport(obj, "error", err, params);
  52         va_end(params);
  53         return -1;
  54 }
  55
  56 static int objwarning(struct object *obj, const char *err, ...)
  57 {
  58         va_list params;
  59         va_start(params, err);
  60         objreport(obj, "warning", err, params);
  61         va_end(params);
  62         return -1;
  63 }
  64
  65 /*
  66  * Check a single reachable object
  67  */
  68 static void check_reachable_object(struct object *obj)
  69 {
  70         const struct object_refs *refs;
  71
  72         /*
  73          * We obviously want the object to be parsed,
  74          * except if it was in a pack-file and we didn't
  75          * do a full fsck
  76          */
  77         if (!obj->parsed) {
  78                 if (has_sha1_pack(obj->sha1, NULL))
  79                         return; /* it is in pack - forget about it */
  80                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
  81                 errors_found |= ERROR_REACHABLE;
  82                 return;
  83         }
  84
  85         /*
  86          * Check that everything that we try to reference is also good.
  87          */
  88         refs = lookup_object_refs(obj);
  89         if (refs) {
  90                 unsigned j;
  91                 for (j = 0; j < refs->count; j++) {
  92                         struct object *ref = refs->ref[j];
  93                         if (ref->parsed ||
  94                             (has_sha1_file(ref->sha1)))
  95                                 continue;
  96                         printf("broken link from %7s %s\n",
  97                                typename(obj->type), sha1_to_hex(obj->sha1));
  98                         printf("              to %7s %s\n",
  99                                typename(ref->type), sha1_to_hex(ref->sha1));
 100                         errors_found |= ERROR_REACHABLE;
 101                 }
 102         }
 103 }
 104
 105 /*
 106  * Check a single unreachable object
 107  */
 108 static void check_unreachable_object(struct object *obj)
 109 {
 110         /*
 111          * Missing unreachable object? Ignore it. It's not like
 112          * we miss it (since it can't be reached), nor do we want
 113          * to complain about it being unreachable (since it does
 114          * not exist).
 115          */
 116         if (!obj->parsed)
 117                 return;
 118
 119         /*
 120          * Unreachable object that exists? Show it if asked to,
 121          * since this is something that is prunable.
 122          */
 123         if (show_unreachable) {
 124                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 125                 return;
 126         }
 127
 128         /*
 129          * "!used" means that nothing at all points to it, including
 130          * other unreachable objects. In other words, it's the "tip"
 131          * of some set of unreachable objects, usually a commit that
 132          * got dropped.
 133          *
 134          * Such starting points are more interesting than some random
 135          * set of unreachable objects, so we show them even if the user
 136          * hasn't asked for _all_ unreachable objects. If you have
 137          * deleted a branch by mistake, this is a prime candidate to
 138          * start looking at, for example.
 139          */
 140         if (!obj->used) {
 141                 printf("dangling %s %s\n", typename(obj->type),
 142                        sha1_to_hex(obj->sha1));
 143                 if (write_lost_and_found) {
 144                         char *filename = git_path("lost-found/%s/%s",
 145                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 146                                 sha1_to_hex(obj->sha1));
 147                         FILE *f;
 148
 149                         if (safe_create_leading_directories(filename)) {
 150                                 error("Could not create lost-found");
 151                                 return;
 152                         }
 153                         if (!(f = fopen(filename, "w")))
 154                                 die("Could not open %s", filename);
 155                         fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 156                         fclose(f);
 157                 }
 158                 return;
 159         }
 160
 161         /*
 162          * Otherwise? It's there, it's unreachable, and some other unreachable
 163          * object points to it. Ignore it - it's not interesting, and we showed
 164          * all the interesting cases above.
 165          */
 166 }
 167
 168 static void check_object(struct object *obj)
 169 {
 170         if (verbose)
 171                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 172
 173         if (obj->flags & REACHABLE)
 174                 check_reachable_object(obj);
 175         else
 176                 check_unreachable_object(obj);
 177 }
 178
 179 static void check_connectivity(void)
 180 {
 181         int i, max;
 182
 183         /* Look up all the requirements, warn about missing objects.. */
 184         max = get_max_object_index();
 185         if (verbose)
 186                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 187
 188         for (i = 0; i < max; i++) {
 189                 struct object *obj = get_indexed_object(i);
 190
 191                 if (obj)
 192                         check_object(obj);
 193         }
 194 }
 195
 196 /*
 197  * The entries in a tree are ordered in the _path_ order,
 198  * which means that a directory entry is ordered by adding
 199  * a slash to the end of it.
 200  *
 201  * So a directory called "a" is ordered _after_ a file
 202  * called "a.c", because "a/" sorts after "a.c".
 203  */
 204 #define TREE_UNORDERED (-1)
 205 #define TREE_HAS_DUPS  (-2)
 206
 207 static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 208 {
 209         int len1 = strlen(name1);
 210         int len2 = strlen(name2);
 211         int len = len1 < len2 ? len1 : len2;
 212         unsigned char c1, c2;
 213         int cmp;
 214
 215         cmp = memcmp(name1, name2, len);
 216         if (cmp < 0)
 217                 return 0;
 218         if (cmp > 0)
 219                 return TREE_UNORDERED;
 220
 221         /*
 222          * Ok, the first <len> characters are the same.
 223          * Now we need to order the next one, but turn
 224          * a '\0' into a '/' for a directory entry.
 225          */
 226         c1 = name1[len];
 227         c2 = name2[len];
 228         if (!c1 && !c2)
 229                 /*
 230                  * git-write-tree used to write out a nonsense tree that has
 231                  * entries with the same name, one blob and one tree.  Make
 232                  * sure we do not have duplicate entries.
 233                  */
 234                 return TREE_HAS_DUPS;
 235         if (!c1 && S_ISDIR(mode1))
 236                 c1 = '/';
 237         if (!c2 && S_ISDIR(mode2))
 238                 c2 = '/';
 239         return c1 < c2 ? 0 : TREE_UNORDERED;
 240 }
 241
 242 static int fsck_tree(struct tree *item)
 243 {
 244         int retval;
 245         int has_full_path = 0;
 246         int has_empty_name = 0;
 247         int has_zero_pad = 0;
 248         int has_bad_modes = 0;
 249         int has_dup_entries = 0;
 250         int not_properly_sorted = 0;
 251         struct tree_desc desc;
 252         unsigned o_mode;
 253         const char *o_name;
 254         const unsigned char *o_sha1;
 255
 256         if (verbose)
 257                 fprintf(stderr, "Checking tree %s\n",
 258                                 sha1_to_hex(item->object.sha1));
 259
 260         init_tree_desc(&desc, item->buffer, item->size);
 261
 262         o_mode = 0;
 263         o_name = NULL;
 264         o_sha1 = NULL;
 265         while (desc.size) {
 266                 unsigned mode;
 267                 const char *name;
 268                 const unsigned char *sha1;
 269
 270                 sha1 = tree_entry_extract(&desc, &name, &mode);
 271
 272                 if (strchr(name, '/'))
 273                         has_full_path = 1;
 274                 if (!*name)
 275                         has_empty_name = 1;
 276                 has_zero_pad |= *(char *)desc.buffer == '0';
 277                 update_tree_entry(&desc);
 278
 279                 switch (mode) {
 280                 /*
 281                  * Standard modes..
 282                  */
 283                 case S_IFREG | 0755:
 284                 case S_IFREG | 0644:
 285                 case S_IFLNK:
 286                 case S_IFDIR:
 287                 case S_IFGITLINK:
 288                         break;
 289                 /*
 290                  * This is nonstandard, but we had a few of these
 291                  * early on when we honored the full set of mode
 292                  * bits..
 293                  */
 294                 case S_IFREG | 0664:
 295                         if (!check_strict)
 296                                 break;
 297                 default:
 298                         has_bad_modes = 1;
 299                 }
 300
 301                 if (o_name) {
 302                         switch (verify_ordered(o_mode, o_name, mode, name)) {
 303                         case TREE_UNORDERED:
 304                                 not_properly_sorted = 1;
 305                                 break;
 306                         case TREE_HAS_DUPS:
 307                                 has_dup_entries = 1;
 308                                 break;
 309                         default:
 310                                 break;
 311                         }
 312                 }
 313
 314                 o_mode = mode;
 315                 o_name = name;
 316                 o_sha1 = sha1;
 317         }
 318         free(item->buffer);
 319         item->buffer = NULL;
 320
 321         retval = 0;
 322         if (has_full_path) {
 323                 objwarning(&item->object, "contains full pathnames");
 324         }
 325         if (has_empty_name) {
 326                 objwarning(&item->object, "contains empty pathname");
 327         }
 328         if (has_zero_pad) {
 329                 objwarning(&item->object, "contains zero-padded file modes");
 330         }
 331         if (has_bad_modes) {
 332                 objwarning(&item->object, "contains bad file modes");
 333         }
 334         if (has_dup_entries) {
 335                 retval = objerror(&item->object, "contains duplicate file entries");
 336         }
 337         if (not_properly_sorted) {
 338                 retval = objerror(&item->object, "not properly sorted");
 339         }
 340         return retval;
 341 }
 342
 343 static int fsck_commit(struct commit *commit)
 344 {
 345         char *buffer = commit->buffer;
 346         unsigned char tree_sha1[20], sha1[20];
 347
 348         if (verbose)
 349                 fprintf(stderr, "Checking commit %s\n",
 350                         sha1_to_hex(commit->object.sha1));
 351
 352         if (memcmp(buffer, "tree ", 5))
 353                 return objerror(&commit->object, "invalid format - expected 'tree' line");
 354         if (get_sha1_hex(buffer+5, tree_sha1) || buffer[45] != '\n')
 355                 return objerror(&commit->object, "invalid 'tree' line format - bad sha1");
 356         buffer += 46;
 357         while (!memcmp(buffer, "parent ", 7)) {
 358                 if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
 359                         return objerror(&commit->object, "invalid 'parent' line format - bad sha1");
 360                 buffer += 48;
 361         }
 362         if (memcmp(buffer, "author ", 7))
 363                 return objerror(&commit->object, "invalid format - expected 'author' line");
 364         free(commit->buffer);
 365         commit->buffer = NULL;
 366         if (!commit->tree)
 367                 return objerror(&commit->object, "could not load commit's tree %s", tree_sha1);
 368         if (!commit->parents && show_root)
 369                 printf("root %s\n", sha1_to_hex(commit->object.sha1));
 370         if (!commit->date)
 371                 printf("bad commit date in %s\n",
 372                        sha1_to_hex(commit->object.sha1));
 373         return 0;
 374 }
 375
 376 static int fsck_tag(struct tag *tag)
 377 {
 378         struct object *tagged = tag->tagged;
 379
 380         if (verbose)
 381                 fprintf(stderr, "Checking tag %s\n",
 382                         sha1_to_hex(tag->object.sha1));
 383
 384         if (!tagged) {
 385                 return objerror(&tag->object, "could not load tagged object");
 386         }
 387         if (!show_tags)
 388                 return 0;
 389
 390         printf("tagged %s %s", typename(tagged->type), sha1_to_hex(tagged->sha1));
 391         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 392         return 0;
 393 }
 394
 395 static int fsck_sha1(const unsigned char *sha1)
 396 {
 397         struct object *obj = parse_object(sha1);
 398         if (!obj) {
 399                 errors_found |= ERROR_OBJECT;
 400                 return error("%s: object corrupt or missing",
 401                              sha1_to_hex(sha1));
 402         }
 403         if (obj->flags & SEEN)
 404                 return 0;
 405         obj->flags |= SEEN;
 406         if (obj->type == OBJ_BLOB)
 407                 return 0;
 408         if (obj->type == OBJ_TREE)
 409                 return fsck_tree((struct tree *) obj);
 410         if (obj->type == OBJ_COMMIT)
 411                 return fsck_commit((struct commit *) obj);
 412         if (obj->type == OBJ_TAG)
 413                 return fsck_tag((struct tag *) obj);
 414
 415         /* By now, parse_object() would've returned NULL instead. */
 416         return objerror(obj, "unknown type '%d' (internal fsck error)",
 417                         obj->type);
 418 }
 419
 420 /*
 421  * This is the sorting chunk size: make it reasonably
 422  * big so that we can sort well..
 423  */
 424 #define MAX_SHA1_ENTRIES (1024)
 425
 426 struct sha1_entry {
 427         unsigned long ino;
 428         unsigned char sha1[20];
 429 };
 430
 431 static struct {
 432         unsigned long nr;
 433         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 434 } sha1_list;
 435
 436 static int ino_compare(const void *_a, const void *_b)
 437 {
 438         const struct sha1_entry *a = _a, *b = _b;
 439         unsigned long ino1 = a->ino, ino2 = b->ino;
 440         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 441 }
 442
 443 static void fsck_sha1_list(void)
 444 {
 445         int i, nr = sha1_list.nr;
 446
 447         if (SORT_DIRENT)
 448                 qsort(sha1_list.entry, nr,
 449                       sizeof(struct sha1_entry *), ino_compare);
 450         for (i = 0; i < nr; i++) {
 451                 struct sha1_entry *entry = sha1_list.entry[i];
 452                 unsigned char *sha1 = entry->sha1;
 453
 454                 sha1_list.entry[i] = NULL;
 455                 fsck_sha1(sha1);
 456                 free(entry);
 457         }
 458         sha1_list.nr = 0;
 459 }
 460
 461 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 462 {
 463         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 464         int nr;
 465
 466         entry->ino = ino;
 467         hashcpy(entry->sha1, sha1);
 468         nr = sha1_list.nr;
 469         if (nr == MAX_SHA1_ENTRIES) {
 470                 fsck_sha1_list();
 471                 nr = 0;
 472         }
 473         sha1_list.entry[nr] = entry;
 474         sha1_list.nr = ++nr;
 475 }
 476
 477 static void fsck_dir(int i, char *path)
 478 {
 479         DIR *dir = opendir(path);
 480         struct dirent *de;
 481
 482         if (!dir)
 483                 return;
 484
 485         if (verbose)
 486                 fprintf(stderr, "Checking directory %s\n", path);
 487
 488         while ((de = readdir(dir)) != NULL) {
 489                 char name[100];
 490                 unsigned char sha1[20];
 491                 int len = strlen(de->d_name);
 492
 493                 switch (len) {
 494                 case 2:
 495                         if (de->d_name[1] != '.')
 496                                 break;
 497                 case 1:
 498                         if (de->d_name[0] != '.')
 499                                 break;
 500                         continue;
 501                 case 38:
 502                         sprintf(name, "%02x", i);
 503                         memcpy(name+2, de->d_name, len+1);
 504                         if (get_sha1_hex(name, sha1) < 0)
 505                                 break;
 506                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 507                         continue;
 508                 }
 509                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 510         }
 511         closedir(dir);
 512 }
 513
 514 static int default_refs;
 515
 516 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 517                 const char *email, unsigned long timestamp, int tz,
 518                 const char *message, void *cb_data)
 519 {
 520         struct object *obj;
 521
 522         if (verbose)
 523                 fprintf(stderr, "Checking reflog %s->%s\n",
 524                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 525
 526         if (!is_null_sha1(osha1)) {
 527                 obj = lookup_object(osha1);
 528                 if (obj) {
 529                         obj->used = 1;
 530                         mark_reachable(obj, REACHABLE);
 531                 }
 532         }
 533         obj = lookup_object(nsha1);
 534         if (obj) {
 535                 obj->used = 1;
 536                 mark_reachable(obj, REACHABLE);
 537         }
 538         return 0;
 539 }
 540
 541 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 542 {
 543         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 544         return 0;
 545 }
 546
 547 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 548 {
 549         struct object *obj;
 550
 551         obj = lookup_object(sha1);
 552         if (!obj) {
 553                 if (has_sha1_file(sha1)) {
 554                         default_refs++;
 555                         return 0; /* it is in a pack */
 556                 }
 557                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 558                 /* We'll continue with the rest despite the error.. */
 559                 return 0;
 560         }
 561         default_refs++;
 562         obj->used = 1;
 563         mark_reachable(obj, REACHABLE);
 564
 565         return 0;
 566 }
 567
 568 static void get_default_heads(void)
 569 {
 570         for_each_ref(fsck_handle_ref, NULL);
 571         if (include_reflogs)
 572                 for_each_reflog(fsck_handle_reflog, NULL);
 573
 574         /*
 575          * Not having any default heads isn't really fatal, but
 576          * it does mean that "--unreachable" no longer makes any
 577          * sense (since in this case everything will obviously
 578          * be unreachable by definition.
 579          *
 580          * Showing dangling objects is valid, though (as those
 581          * dangling objects are likely lost heads).
 582          *
 583          * So we just print a warning about it, and clear the
 584          * "show_unreachable" flag.
 585          */
 586         if (!default_refs) {
 587                 fprintf(stderr, "notice: No default references\n");
 588                 show_unreachable = 0;
 589         }
 590 }
 591
 592 static void fsck_object_dir(const char *path)
 593 {
 594         int i;
 595
 596         if (verbose)
 597                 fprintf(stderr, "Checking object directory\n");
 598
 599         for (i = 0; i < 256; i++) {
 600                 static char dir[4096];
 601                 sprintf(dir, "%s/%02x", path, i);
 602                 fsck_dir(i, dir);
 603         }
 604         fsck_sha1_list();
 605 }
 606
 607 static int fsck_head_link(void)
 608 {
 609         unsigned char sha1[20];
 610         int flag;
 611         int null_is_error = 0;
 612         const char *head_points_at = resolve_ref("HEAD", sha1, 0, &flag);
 613
 614         if (verbose)
 615                 fprintf(stderr, "Checking HEAD link\n");
 616
 617         if (!head_points_at)
 618                 return error("Invalid HEAD");
 619         if (!strcmp(head_points_at, "HEAD"))
 620                 /* detached HEAD */
 621                 null_is_error = 1;
 622         else if (prefixcmp(head_points_at, "refs/heads/"))
 623                 return error("HEAD points to something strange (%s)",
 624                              head_points_at);
 625         if (is_null_sha1(sha1)) {
 626                 if (null_is_error)
 627                         return error("HEAD: detached HEAD points at nothing");
 628                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 629                         head_points_at + 11);
 630         }
 631         return 0;
 632 }
 633
 634 static int fsck_cache_tree(struct cache_tree *it)
 635 {
 636         int i;
 637         int err = 0;
 638
 639         if (verbose)
 640                 fprintf(stderr, "Checking cache tree\n");
 641
 642         if (0 <= it->entry_count) {
 643                 struct object *obj = parse_object(it->sha1);
 644                 if (!obj) {
 645                         error("%s: invalid sha1 pointer in cache-tree",
 646                               sha1_to_hex(it->sha1));
 647                         return 1;
 648                 }
 649                 mark_reachable(obj, REACHABLE);
 650                 obj->used = 1;
 651                 if (obj->type != OBJ_TREE)
 652                         err |= objerror(obj, "non-tree in cache-tree");
 653         }
 654         for (i = 0; i < it->subtree_nr; i++)
 655                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 656         return err;
 657 }
 658
 659 static const char fsck_usage[] =
 660 "git-fsck [--tags] [--root] [[--unreachable] [--cache] [--full] "
 661 "[--strict] [--verbose] <head-sha1>*]";
 662
 663 int cmd_fsck(int argc, const char **argv, const char *prefix)
 664 {
 665         int i, heads;
 666
 667         track_object_refs = 1;
 668         errors_found = 0;
 669
 670         for (i = 1; i < argc; i++) {
 671                 const char *arg = argv[i];
 672
 673                 if (!strcmp(arg, "--unreachable")) {
 674                         show_unreachable = 1;
 675                         continue;
 676                 }
 677                 if (!strcmp(arg, "--tags")) {
 678                         show_tags = 1;
 679                         continue;
 680                 }
 681                 if (!strcmp(arg, "--root")) {
 682                         show_root = 1;
 683                         continue;
 684                 }
 685                 if (!strcmp(arg, "--cache")) {
 686                         keep_cache_objects = 1;
 687                         continue;
 688                 }
 689                 if (!strcmp(arg, "--no-reflogs")) {
 690                         include_reflogs = 0;
 691                         continue;
 692                 }
 693                 if (!strcmp(arg, "--full")) {
 694                         check_full = 1;
 695                         continue;
 696                 }
 697                 if (!strcmp(arg, "--strict")) {
 698                         check_strict = 1;
 699                         continue;
 700                 }
 701                 if (!strcmp(arg, "--verbose")) {
 702                         verbose = 1;
 703                         continue;
 704                 }
 705                 if (!strcmp(arg, "--lost-found")) {
 706                         check_full = 1;
 707                         include_reflogs = 0;
 708                         write_lost_and_found = 1;
 709                         continue;
 710                 }
 711                 if (*arg == '-')
 712                         usage(fsck_usage);
 713         }
 714
 715         fsck_head_link();
 716         fsck_object_dir(get_object_directory());
 717         if (check_full) {
 718                 struct alternate_object_database *alt;
 719                 struct packed_git *p;
 720                 prepare_alt_odb();
 721                 for (alt = alt_odb_list; alt; alt = alt->next) {
 722                         char namebuf[PATH_MAX];
 723                         int namelen = alt->name - alt->base;
 724                         memcpy(namebuf, alt->base, namelen);
 725                         namebuf[namelen - 1] = 0;
 726                         fsck_object_dir(namebuf);
 727                 }
 728                 prepare_packed_git();
 729                 for (p = packed_git; p; p = p->next)
 730                         /* verify gives error messages itself */
 731                         verify_pack(p, 0);
 732
 733                 for (p = packed_git; p; p = p->next) {
 734                         uint32_t i, num;
 735                         if (open_pack_index(p))
 736                                 continue;
 737                         num = p->num_objects;
 738                         for (i = 0; i < num; i++)
 739                                 fsck_sha1(nth_packed_object_sha1(p, i));
 740                 }
 741         }
 742
 743         heads = 0;
 744         for (i = 1; i < argc; i++) {
 745                 const char *arg = argv[i];
 746
 747                 if (*arg == '-')
 748                         continue;
 749
 750                 if (!get_sha1(arg, head_sha1)) {
 751                         struct object *obj = lookup_object(head_sha1);
 752
 753                         /* Error is printed by lookup_object(). */
 754                         if (!obj)
 755                                 continue;
 756
 757                         obj->used = 1;
 758                         mark_reachable(obj, REACHABLE);
 759                         heads++;
 760                         continue;
 761                 }
 762                 error("invalid parameter: expected sha1, got '%s'", arg);
 763         }
 764
 765         /*
 766          * If we've not been given any explicit head information, do the
 767          * default ones from .git/refs. We also consider the index file
 768          * in this case (ie this implies --cache).
 769          */
 770         if (!heads) {
 771                 get_default_heads();
 772                 keep_cache_objects = 1;
 773         }
 774
 775         if (keep_cache_objects) {
 776                 int i;
 777                 read_cache();
 778                 for (i = 0; i < active_nr; i++) {
 779                         unsigned int mode;
 780                         struct blob *blob;
 781                         struct object *obj;
 782
 783                         mode = ntohl(active_cache[i]->ce_mode);
 784                         if (S_ISGITLINK(mode))
 785                                 continue;
 786                         blob = lookup_blob(active_cache[i]->sha1);
 787                         if (!blob)
 788                                 continue;
 789                         obj = &blob->object;
 790                         obj->used = 1;
 791                         mark_reachable(obj, REACHABLE);
 792                 }
 793                 if (active_cache_tree)
 794                         fsck_cache_tree(active_cache_tree);
 795         }
 796
 797         check_connectivity();
 798         return errors_found;
 799 }