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                         if (obj->type == OBJ_BLOB) {
 156                                 enum object_type type;
 157                                 unsigned long size;
 158                                 char *buf = read_sha1_file(obj->sha1,
 159                                                 &type, &size);
 160                                 if (buf) {
 161                                         fwrite(buf, size, 1, f);
 162                                         free(buf);
 163                                 }
 164                         } else
 165                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 166                         fclose(f);
 167                 }
 168                 return;
 169         }
 170
 171         /*
 172          * Otherwise? It's there, it's unreachable, and some other unreachable
 173          * object points to it. Ignore it - it's not interesting, and we showed
 174          * all the interesting cases above.
 175          */
 176 }
 177
 178 static void check_object(struct object *obj)
 179 {
 180         if (verbose)
 181                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 182
 183         if (obj->flags & REACHABLE)
 184                 check_reachable_object(obj);
 185         else
 186                 check_unreachable_object(obj);
 187 }
 188
 189 static void check_connectivity(void)
 190 {
 191         int i, max;
 192
 193         /* Look up all the requirements, warn about missing objects.. */
 194         max = get_max_object_index();
 195         if (verbose)
 196                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 197
 198         for (i = 0; i < max; i++) {
 199                 struct object *obj = get_indexed_object(i);
 200
 201                 if (obj)
 202                         check_object(obj);
 203         }
 204 }
 205
 206 /*
 207  * The entries in a tree are ordered in the _path_ order,
 208  * which means that a directory entry is ordered by adding
 209  * a slash to the end of it.
 210  *
 211  * So a directory called "a" is ordered _after_ a file
 212  * called "a.c", because "a/" sorts after "a.c".
 213  */
 214 #define TREE_UNORDERED (-1)
 215 #define TREE_HAS_DUPS  (-2)
 216
 217 static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 218 {
 219         int len1 = strlen(name1);
 220         int len2 = strlen(name2);
 221         int len = len1 < len2 ? len1 : len2;
 222         unsigned char c1, c2;
 223         int cmp;
 224
 225         cmp = memcmp(name1, name2, len);
 226         if (cmp < 0)
 227                 return 0;
 228         if (cmp > 0)
 229                 return TREE_UNORDERED;
 230
 231         /*
 232          * Ok, the first <len> characters are the same.
 233          * Now we need to order the next one, but turn
 234          * a '\0' into a '/' for a directory entry.
 235          */
 236         c1 = name1[len];
 237         c2 = name2[len];
 238         if (!c1 && !c2)
 239                 /*
 240                  * git-write-tree used to write out a nonsense tree that has
 241                  * entries with the same name, one blob and one tree.  Make
 242                  * sure we do not have duplicate entries.
 243                  */
 244                 return TREE_HAS_DUPS;
 245         if (!c1 && S_ISDIR(mode1))
 246                 c1 = '/';
 247         if (!c2 && S_ISDIR(mode2))
 248                 c2 = '/';
 249         return c1 < c2 ? 0 : TREE_UNORDERED;
 250 }
 251
 252 static int fsck_tree(struct tree *item)
 253 {
 254         int retval;
 255         int has_full_path = 0;
 256         int has_empty_name = 0;
 257         int has_zero_pad = 0;
 258         int has_bad_modes = 0;
 259         int has_dup_entries = 0;
 260         int not_properly_sorted = 0;
 261         struct tree_desc desc;
 262         unsigned o_mode;
 263         const char *o_name;
 264         const unsigned char *o_sha1;
 265
 266         if (verbose)
 267                 fprintf(stderr, "Checking tree %s\n",
 268                                 sha1_to_hex(item->object.sha1));
 269
 270         init_tree_desc(&desc, item->buffer, item->size);
 271
 272         o_mode = 0;
 273         o_name = NULL;
 274         o_sha1 = NULL;
 275         while (desc.size) {
 276                 unsigned mode;
 277                 const char *name;
 278                 const unsigned char *sha1;
 279
 280                 sha1 = tree_entry_extract(&desc, &name, &mode);
 281
 282                 if (strchr(name, '/'))
 283                         has_full_path = 1;
 284                 if (!*name)
 285                         has_empty_name = 1;
 286                 has_zero_pad |= *(char *)desc.buffer == '0';
 287                 update_tree_entry(&desc);
 288
 289                 switch (mode) {
 290                 /*
 291                  * Standard modes..
 292                  */
 293                 case S_IFREG | 0755:
 294                 case S_IFREG | 0644:
 295                 case S_IFLNK:
 296                 case S_IFDIR:
 297                 case S_IFGITLINK:
 298                         break;
 299                 /*
 300                  * This is nonstandard, but we had a few of these
 301                  * early on when we honored the full set of mode
 302                  * bits..
 303                  */
 304                 case S_IFREG | 0664:
 305                         if (!check_strict)
 306                                 break;
 307                 default:
 308                         has_bad_modes = 1;
 309                 }
 310
 311                 if (o_name) {
 312                         switch (verify_ordered(o_mode, o_name, mode, name)) {
 313                         case TREE_UNORDERED:
 314                                 not_properly_sorted = 1;
 315                                 break;
 316                         case TREE_HAS_DUPS:
 317                                 has_dup_entries = 1;
 318                                 break;
 319                         default:
 320                                 break;
 321                         }
 322                 }
 323
 324                 o_mode = mode;
 325                 o_name = name;
 326                 o_sha1 = sha1;
 327         }
 328         free(item->buffer);
 329         item->buffer = NULL;
 330
 331         retval = 0;
 332         if (has_full_path) {
 333                 objwarning(&item->object, "contains full pathnames");
 334         }
 335         if (has_empty_name) {
 336                 objwarning(&item->object, "contains empty pathname");
 337         }
 338         if (has_zero_pad) {
 339                 objwarning(&item->object, "contains zero-padded file modes");
 340         }
 341         if (has_bad_modes) {
 342                 objwarning(&item->object, "contains bad file modes");
 343         }
 344         if (has_dup_entries) {
 345                 retval = objerror(&item->object, "contains duplicate file entries");
 346         }
 347         if (not_properly_sorted) {
 348                 retval = objerror(&item->object, "not properly sorted");
 349         }
 350         return retval;
 351 }
 352
 353 static int fsck_commit(struct commit *commit)
 354 {
 355         char *buffer = commit->buffer;
 356         unsigned char tree_sha1[20], sha1[20];
 357
 358         if (verbose)
 359                 fprintf(stderr, "Checking commit %s\n",
 360                         sha1_to_hex(commit->object.sha1));
 361
 362         if (memcmp(buffer, "tree ", 5))
 363                 return objerror(&commit->object, "invalid format - expected 'tree' line");
 364         if (get_sha1_hex(buffer+5, tree_sha1) || buffer[45] != '\n')
 365                 return objerror(&commit->object, "invalid 'tree' line format - bad sha1");
 366         buffer += 46;
 367         while (!memcmp(buffer, "parent ", 7)) {
 368                 if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
 369                         return objerror(&commit->object, "invalid 'parent' line format - bad sha1");
 370                 buffer += 48;
 371         }
 372         if (memcmp(buffer, "author ", 7))
 373                 return objerror(&commit->object, "invalid format - expected 'author' line");
 374         free(commit->buffer);
 375         commit->buffer = NULL;
 376         if (!commit->tree)
 377                 return objerror(&commit->object, "could not load commit's tree %s", tree_sha1);
 378         if (!commit->parents && show_root)
 379                 printf("root %s\n", sha1_to_hex(commit->object.sha1));
 380         if (!commit->date)
 381                 printf("bad commit date in %s\n",
 382                        sha1_to_hex(commit->object.sha1));
 383         return 0;
 384 }
 385
 386 static int fsck_tag(struct tag *tag)
 387 {
 388         struct object *tagged = tag->tagged;
 389
 390         if (verbose)
 391                 fprintf(stderr, "Checking tag %s\n",
 392                         sha1_to_hex(tag->object.sha1));
 393
 394         if (!tagged) {
 395                 return objerror(&tag->object, "could not load tagged object");
 396         }
 397         if (!show_tags)
 398                 return 0;
 399
 400         printf("tagged %s %s", typename(tagged->type), sha1_to_hex(tagged->sha1));
 401         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 402         return 0;
 403 }
 404
 405 static int fsck_sha1(const unsigned char *sha1)
 406 {
 407         struct object *obj = parse_object(sha1);
 408         if (!obj) {
 409                 errors_found |= ERROR_OBJECT;
 410                 return error("%s: object corrupt or missing",
 411                              sha1_to_hex(sha1));
 412         }
 413         if (obj->flags & SEEN)
 414                 return 0;
 415         obj->flags |= SEEN;
 416         if (obj->type == OBJ_BLOB)
 417                 return 0;
 418         if (obj->type == OBJ_TREE)
 419                 return fsck_tree((struct tree *) obj);
 420         if (obj->type == OBJ_COMMIT)
 421                 return fsck_commit((struct commit *) obj);
 422         if (obj->type == OBJ_TAG)
 423                 return fsck_tag((struct tag *) obj);
 424
 425         /* By now, parse_object() would've returned NULL instead. */
 426         return objerror(obj, "unknown type '%d' (internal fsck error)",
 427                         obj->type);
 428 }
 429
 430 /*
 431  * This is the sorting chunk size: make it reasonably
 432  * big so that we can sort well..
 433  */
 434 #define MAX_SHA1_ENTRIES (1024)
 435
 436 struct sha1_entry {
 437         unsigned long ino;
 438         unsigned char sha1[20];
 439 };
 440
 441 static struct {
 442         unsigned long nr;
 443         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 444 } sha1_list;
 445
 446 static int ino_compare(const void *_a, const void *_b)
 447 {
 448         const struct sha1_entry *a = _a, *b = _b;
 449         unsigned long ino1 = a->ino, ino2 = b->ino;
 450         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 451 }
 452
 453 static void fsck_sha1_list(void)
 454 {
 455         int i, nr = sha1_list.nr;
 456
 457         if (SORT_DIRENT)
 458                 qsort(sha1_list.entry, nr,
 459                       sizeof(struct sha1_entry *), ino_compare);
 460         for (i = 0; i < nr; i++) {
 461                 struct sha1_entry *entry = sha1_list.entry[i];
 462                 unsigned char *sha1 = entry->sha1;
 463
 464                 sha1_list.entry[i] = NULL;
 465                 fsck_sha1(sha1);
 466                 free(entry);
 467         }
 468         sha1_list.nr = 0;
 469 }
 470
 471 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 472 {
 473         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 474         int nr;
 475
 476         entry->ino = ino;
 477         hashcpy(entry->sha1, sha1);
 478         nr = sha1_list.nr;
 479         if (nr == MAX_SHA1_ENTRIES) {
 480                 fsck_sha1_list();
 481                 nr = 0;
 482         }
 483         sha1_list.entry[nr] = entry;
 484         sha1_list.nr = ++nr;
 485 }
 486
 487 static void fsck_dir(int i, char *path)
 488 {
 489         DIR *dir = opendir(path);
 490         struct dirent *de;
 491
 492         if (!dir)
 493                 return;
 494
 495         if (verbose)
 496                 fprintf(stderr, "Checking directory %s\n", path);
 497
 498         while ((de = readdir(dir)) != NULL) {
 499                 char name[100];
 500                 unsigned char sha1[20];
 501                 int len = strlen(de->d_name);
 502
 503                 switch (len) {
 504                 case 2:
 505                         if (de->d_name[1] != '.')
 506                                 break;
 507                 case 1:
 508                         if (de->d_name[0] != '.')
 509                                 break;
 510                         continue;
 511                 case 38:
 512                         sprintf(name, "%02x", i);
 513                         memcpy(name+2, de->d_name, len+1);
 514                         if (get_sha1_hex(name, sha1) < 0)
 515                                 break;
 516                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 517                         continue;
 518                 }
 519                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 520         }
 521         closedir(dir);
 522 }
 523
 524 static int default_refs;
 525
 526 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 527                 const char *email, unsigned long timestamp, int tz,
 528                 const char *message, void *cb_data)
 529 {
 530         struct object *obj;
 531
 532         if (verbose)
 533                 fprintf(stderr, "Checking reflog %s->%s\n",
 534                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 535
 536         if (!is_null_sha1(osha1)) {
 537                 obj = lookup_object(osha1);
 538                 if (obj) {
 539                         obj->used = 1;
 540                         mark_reachable(obj, REACHABLE);
 541                 }
 542         }
 543         obj = lookup_object(nsha1);
 544         if (obj) {
 545                 obj->used = 1;
 546                 mark_reachable(obj, REACHABLE);
 547         }
 548         return 0;
 549 }
 550
 551 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 552 {
 553         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 554         return 0;
 555 }
 556
 557 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 558 {
 559         struct object *obj;
 560
 561         obj = lookup_object(sha1);
 562         if (!obj) {
 563                 if (has_sha1_file(sha1)) {
 564                         default_refs++;
 565                         return 0; /* it is in a pack */
 566                 }
 567                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 568                 /* We'll continue with the rest despite the error.. */
 569                 return 0;
 570         }
 571         default_refs++;
 572         obj->used = 1;
 573         mark_reachable(obj, REACHABLE);
 574
 575         return 0;
 576 }
 577
 578 static void get_default_heads(void)
 579 {
 580         for_each_ref(fsck_handle_ref, NULL);
 581         if (include_reflogs)
 582                 for_each_reflog(fsck_handle_reflog, NULL);
 583
 584         /*
 585          * Not having any default heads isn't really fatal, but
 586          * it does mean that "--unreachable" no longer makes any
 587          * sense (since in this case everything will obviously
 588          * be unreachable by definition.
 589          *
 590          * Showing dangling objects is valid, though (as those
 591          * dangling objects are likely lost heads).
 592          *
 593          * So we just print a warning about it, and clear the
 594          * "show_unreachable" flag.
 595          */
 596         if (!default_refs) {
 597                 fprintf(stderr, "notice: No default references\n");
 598                 show_unreachable = 0;
 599         }
 600 }
 601
 602 static void fsck_object_dir(const char *path)
 603 {
 604         int i;
 605
 606         if (verbose)
 607                 fprintf(stderr, "Checking object directory\n");
 608
 609         for (i = 0; i < 256; i++) {
 610                 static char dir[4096];
 611                 sprintf(dir, "%s/%02x", path, i);
 612                 fsck_dir(i, dir);
 613         }
 614         fsck_sha1_list();
 615 }
 616
 617 static int fsck_head_link(void)
 618 {
 619         unsigned char sha1[20];
 620         int flag;
 621         int null_is_error = 0;
 622         const char *head_points_at = resolve_ref("HEAD", sha1, 0, &flag);
 623
 624         if (verbose)
 625                 fprintf(stderr, "Checking HEAD link\n");
 626
 627         if (!head_points_at)
 628                 return error("Invalid HEAD");
 629         if (!strcmp(head_points_at, "HEAD"))
 630                 /* detached HEAD */
 631                 null_is_error = 1;
 632         else if (prefixcmp(head_points_at, "refs/heads/"))
 633                 return error("HEAD points to something strange (%s)",
 634                              head_points_at);
 635         if (is_null_sha1(sha1)) {
 636                 if (null_is_error)
 637                         return error("HEAD: detached HEAD points at nothing");
 638                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 639                         head_points_at + 11);
 640         }
 641         return 0;
 642 }
 643
 644 static int fsck_cache_tree(struct cache_tree *it)
 645 {
 646         int i;
 647         int err = 0;
 648
 649         if (verbose)
 650                 fprintf(stderr, "Checking cache tree\n");
 651
 652         if (0 <= it->entry_count) {
 653                 struct object *obj = parse_object(it->sha1);
 654                 if (!obj) {
 655                         error("%s: invalid sha1 pointer in cache-tree",
 656                               sha1_to_hex(it->sha1));
 657                         return 1;
 658                 }
 659                 mark_reachable(obj, REACHABLE);
 660                 obj->used = 1;
 661                 if (obj->type != OBJ_TREE)
 662                         err |= objerror(obj, "non-tree in cache-tree");
 663         }
 664         for (i = 0; i < it->subtree_nr; i++)
 665                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 666         return err;
 667 }
 668
 669 static const char fsck_usage[] =
 670 "git-fsck [--tags] [--root] [[--unreachable] [--cache] [--full] "
 671 "[--strict] [--verbose] <head-sha1>*]";
 672
 673 int cmd_fsck(int argc, const char **argv, const char *prefix)
 674 {
 675         int i, heads;
 676
 677         track_object_refs = 1;
 678         errors_found = 0;
 679
 680         for (i = 1; i < argc; i++) {
 681                 const char *arg = argv[i];
 682
 683                 if (!strcmp(arg, "--unreachable")) {
 684                         show_unreachable = 1;
 685                         continue;
 686                 }
 687                 if (!strcmp(arg, "--tags")) {
 688                         show_tags = 1;
 689                         continue;
 690                 }
 691                 if (!strcmp(arg, "--root")) {
 692                         show_root = 1;
 693                         continue;
 694                 }
 695                 if (!strcmp(arg, "--cache")) {
 696                         keep_cache_objects = 1;
 697                         continue;
 698                 }
 699                 if (!strcmp(arg, "--no-reflogs")) {
 700                         include_reflogs = 0;
 701                         continue;
 702                 }
 703                 if (!strcmp(arg, "--full")) {
 704                         check_full = 1;
 705                         continue;
 706                 }
 707                 if (!strcmp(arg, "--strict")) {
 708                         check_strict = 1;
 709                         continue;
 710                 }
 711                 if (!strcmp(arg, "--verbose")) {
 712                         verbose = 1;
 713                         continue;
 714                 }
 715                 if (!strcmp(arg, "--lost-found")) {
 716                         check_full = 1;
 717                         include_reflogs = 0;
 718                         write_lost_and_found = 1;
 719                         continue;
 720                 }
 721                 if (*arg == '-')
 722                         usage(fsck_usage);
 723         }
 724
 725         fsck_head_link();
 726         fsck_object_dir(get_object_directory());
 727         if (check_full) {
 728                 struct alternate_object_database *alt;
 729                 struct packed_git *p;
 730                 prepare_alt_odb();
 731                 for (alt = alt_odb_list; alt; alt = alt->next) {
 732                         char namebuf[PATH_MAX];
 733                         int namelen = alt->name - alt->base;
 734                         memcpy(namebuf, alt->base, namelen);
 735                         namebuf[namelen - 1] = 0;
 736                         fsck_object_dir(namebuf);
 737                 }
 738                 prepare_packed_git();
 739                 for (p = packed_git; p; p = p->next)
 740                         /* verify gives error messages itself */
 741                         verify_pack(p, 0);
 742
 743                 for (p = packed_git; p; p = p->next) {
 744                         uint32_t i, num;
 745                         if (open_pack_index(p))
 746                                 continue;
 747                         num = p->num_objects;
 748                         for (i = 0; i < num; i++)
 749                                 fsck_sha1(nth_packed_object_sha1(p, i));
 750                 }
 751         }
 752
 753         heads = 0;
 754         for (i = 1; i < argc; i++) {
 755                 const char *arg = argv[i];
 756
 757                 if (*arg == '-')
 758                         continue;
 759
 760                 if (!get_sha1(arg, head_sha1)) {
 761                         struct object *obj = lookup_object(head_sha1);
 762
 763                         /* Error is printed by lookup_object(). */
 764                         if (!obj)
 765                                 continue;
 766
 767                         obj->used = 1;
 768                         mark_reachable(obj, REACHABLE);
 769                         heads++;
 770                         continue;
 771                 }
 772                 error("invalid parameter: expected sha1, got '%s'", arg);
 773         }
 774
 775         /*
 776          * If we've not been given any explicit head information, do the
 777          * default ones from .git/refs. We also consider the index file
 778          * in this case (ie this implies --cache).
 779          */
 780         if (!heads) {
 781                 get_default_heads();
 782                 keep_cache_objects = 1;
 783         }
 784
 785         if (keep_cache_objects) {
 786                 int i;
 787                 read_cache();
 788                 for (i = 0; i < active_nr; i++) {
 789                         unsigned int mode;
 790                         struct blob *blob;
 791                         struct object *obj;
 792
 793                         mode = ntohl(active_cache[i]->ce_mode);
 794                         if (S_ISGITLINK(mode))
 795                                 continue;
 796                         blob = lookup_blob(active_cache[i]->sha1);
 797                         if (!blob)
 798                                 continue;
 799                         obj = &blob->object;
 800                         obj->used = 1;
 801                         mark_reachable(obj, REACHABLE);
 802                 }
 803                 if (active_cache_tree)
 804                         fsck_cache_tree(active_cache_tree);
 805         }
 806
 807         check_connectivity();
 808         return errors_found;
 809 }