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 #include "parse-options.h"
  12
  13 #define REACHABLE 0x0001
  14 #define SEEN      0x0002
  15
  16 static int show_root;
  17 static int show_tags;
  18 static int show_unreachable;
  19 static int include_reflogs = 1;
  20 static int check_full;
  21 static int check_strict;
  22 static int keep_cache_objects;
  23 static unsigned char head_sha1[20];
  24 static int errors_found;
  25 static int write_lost_and_found;
  26 static int verbose;
  27 #define ERROR_OBJECT 01
  28 #define ERROR_REACHABLE 02
  29
  30 #ifdef NO_D_INO_IN_DIRENT
  31 #define SORT_DIRENT 0
  32 #define DIRENT_SORT_HINT(de) 0
  33 #else
  34 #define SORT_DIRENT 1
  35 #define DIRENT_SORT_HINT(de) ((de)->d_ino)
  36 #endif
  37
  38 static void objreport(struct object *obj, const char *severity,
  39                       const char *err, va_list params)
  40 {
  41         fprintf(stderr, "%s in %s %s: ",
  42                 severity, typename(obj->type), sha1_to_hex(obj->sha1));
  43         vfprintf(stderr, err, params);
  44         fputs("\n", stderr);
  45 }
  46
  47 static int objerror(struct object *obj, const char *err, ...)
  48 {
  49         va_list params;
  50         va_start(params, err);
  51         errors_found |= ERROR_OBJECT;
  52         objreport(obj, "error", err, params);
  53         va_end(params);
  54         return -1;
  55 }
  56
  57 static int objwarning(struct object *obj, const char *err, ...)
  58 {
  59         va_list params;
  60         va_start(params, err);
  61         objreport(obj, "warning", err, params);
  62         va_end(params);
  63         return -1;
  64 }
  65
  66 /*
  67  * Check a single reachable object
  68  */
  69 static void check_reachable_object(struct object *obj)
  70 {
  71         const struct object_refs *refs;
  72
  73         /*
  74          * We obviously want the object to be parsed,
  75          * except if it was in a pack-file and we didn't
  76          * do a full fsck
  77          */
  78         if (!obj->parsed) {
  79                 if (has_sha1_pack(obj->sha1, NULL))
  80                         return; /* it is in pack - forget about it */
  81                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
  82                 errors_found |= ERROR_REACHABLE;
  83                 return;
  84         }
  85
  86         /*
  87          * Check that everything that we try to reference is also good.
  88          */
  89         refs = lookup_object_refs(obj);
  90         if (refs) {
  91                 unsigned j;
  92                 for (j = 0; j < refs->count; j++) {
  93                         struct object *ref = refs->ref[j];
  94                         if (ref->parsed ||
  95                             (has_sha1_file(ref->sha1)))
  96                                 continue;
  97                         printf("broken link from %7s %s\n",
  98                                typename(obj->type), sha1_to_hex(obj->sha1));
  99                         printf("              to %7s %s\n",
 100                                typename(ref->type), sha1_to_hex(ref->sha1));
 101                         errors_found |= ERROR_REACHABLE;
 102                 }
 103         }
 104 }
 105
 106 /*
 107  * Check a single unreachable object
 108  */
 109 static void check_unreachable_object(struct object *obj)
 110 {
 111         /*
 112          * Missing unreachable object? Ignore it. It's not like
 113          * we miss it (since it can't be reached), nor do we want
 114          * to complain about it being unreachable (since it does
 115          * not exist).
 116          */
 117         if (!obj->parsed)
 118                 return;
 119
 120         /*
 121          * Unreachable object that exists? Show it if asked to,
 122          * since this is something that is prunable.
 123          */
 124         if (show_unreachable) {
 125                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 126                 return;
 127         }
 128
 129         /*
 130          * "!used" means that nothing at all points to it, including
 131          * other unreachable objects. In other words, it's the "tip"
 132          * of some set of unreachable objects, usually a commit that
 133          * got dropped.
 134          *
 135          * Such starting points are more interesting than some random
 136          * set of unreachable objects, so we show them even if the user
 137          * hasn't asked for _all_ unreachable objects. If you have
 138          * deleted a branch by mistake, this is a prime candidate to
 139          * start looking at, for example.
 140          */
 141         if (!obj->used) {
 142                 printf("dangling %s %s\n", typename(obj->type),
 143                        sha1_to_hex(obj->sha1));
 144                 if (write_lost_and_found) {
 145                         char *filename = git_path("lost-found/%s/%s",
 146                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 147                                 sha1_to_hex(obj->sha1));
 148                         FILE *f;
 149
 150                         if (safe_create_leading_directories(filename)) {
 151                                 error("Could not create lost-found");
 152                                 return;
 153                         }
 154                         if (!(f = fopen(filename, "w")))
 155                                 die("Could not open %s", filename);
 156                         if (obj->type == OBJ_BLOB) {
 157                                 enum object_type type;
 158                                 unsigned long size;
 159                                 char *buf = read_sha1_file(obj->sha1,
 160                                                 &type, &size);
 161                                 if (buf) {
 162                                         fwrite(buf, size, 1, f);
 163                                         free(buf);
 164                                 }
 165                         } else
 166                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 167                         fclose(f);
 168                 }
 169                 return;
 170         }
 171
 172         /*
 173          * Otherwise? It's there, it's unreachable, and some other unreachable
 174          * object points to it. Ignore it - it's not interesting, and we showed
 175          * all the interesting cases above.
 176          */
 177 }
 178
 179 static void check_object(struct object *obj)
 180 {
 181         if (verbose)
 182                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 183
 184         if (obj->flags & REACHABLE)
 185                 check_reachable_object(obj);
 186         else
 187                 check_unreachable_object(obj);
 188 }
 189
 190 static void check_connectivity(void)
 191 {
 192         int i, max;
 193
 194         /* Look up all the requirements, warn about missing objects.. */
 195         max = get_max_object_index();
 196         if (verbose)
 197                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 198
 199         for (i = 0; i < max; i++) {
 200                 struct object *obj = get_indexed_object(i);
 201
 202                 if (obj)
 203                         check_object(obj);
 204         }
 205 }
 206
 207 /*
 208  * The entries in a tree are ordered in the _path_ order,
 209  * which means that a directory entry is ordered by adding
 210  * a slash to the end of it.
 211  *
 212  * So a directory called "a" is ordered _after_ a file
 213  * called "a.c", because "a/" sorts after "a.c".
 214  */
 215 #define TREE_UNORDERED (-1)
 216 #define TREE_HAS_DUPS  (-2)
 217
 218 static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 219 {
 220         int len1 = strlen(name1);
 221         int len2 = strlen(name2);
 222         int len = len1 < len2 ? len1 : len2;
 223         unsigned char c1, c2;
 224         int cmp;
 225
 226         cmp = memcmp(name1, name2, len);
 227         if (cmp < 0)
 228                 return 0;
 229         if (cmp > 0)
 230                 return TREE_UNORDERED;
 231
 232         /*
 233          * Ok, the first <len> characters are the same.
 234          * Now we need to order the next one, but turn
 235          * a '\0' into a '/' for a directory entry.
 236          */
 237         c1 = name1[len];
 238         c2 = name2[len];
 239         if (!c1 && !c2)
 240                 /*
 241                  * git-write-tree used to write out a nonsense tree that has
 242                  * entries with the same name, one blob and one tree.  Make
 243                  * sure we do not have duplicate entries.
 244                  */
 245                 return TREE_HAS_DUPS;
 246         if (!c1 && S_ISDIR(mode1))
 247                 c1 = '/';
 248         if (!c2 && S_ISDIR(mode2))
 249                 c2 = '/';
 250         return c1 < c2 ? 0 : TREE_UNORDERED;
 251 }
 252
 253 static int fsck_tree(struct tree *item)
 254 {
 255         int retval;
 256         int has_full_path = 0;
 257         int has_empty_name = 0;
 258         int has_zero_pad = 0;
 259         int has_bad_modes = 0;
 260         int has_dup_entries = 0;
 261         int not_properly_sorted = 0;
 262         struct tree_desc desc;
 263         unsigned o_mode;
 264         const char *o_name;
 265         const unsigned char *o_sha1;
 266
 267         if (verbose)
 268                 fprintf(stderr, "Checking tree %s\n",
 269                                 sha1_to_hex(item->object.sha1));
 270
 271         init_tree_desc(&desc, item->buffer, item->size);
 272
 273         o_mode = 0;
 274         o_name = NULL;
 275         o_sha1 = NULL;
 276         while (desc.size) {
 277                 unsigned mode;
 278                 const char *name;
 279                 const unsigned char *sha1;
 280
 281                 sha1 = tree_entry_extract(&desc, &name, &mode);
 282
 283                 if (strchr(name, '/'))
 284                         has_full_path = 1;
 285                 if (!*name)
 286                         has_empty_name = 1;
 287                 has_zero_pad |= *(char *)desc.buffer == '0';
 288                 update_tree_entry(&desc);
 289
 290                 switch (mode) {
 291                 /*
 292                  * Standard modes..
 293                  */
 294                 case S_IFREG | 0755:
 295                 case S_IFREG | 0644:
 296                 case S_IFLNK:
 297                 case S_IFDIR:
 298                 case S_IFGITLINK:
 299                         break;
 300                 /*
 301                  * This is nonstandard, but we had a few of these
 302                  * early on when we honored the full set of mode
 303                  * bits..
 304                  */
 305                 case S_IFREG | 0664:
 306                         if (!check_strict)
 307                                 break;
 308                 default:
 309                         has_bad_modes = 1;
 310                 }
 311
 312                 if (o_name) {
 313                         switch (verify_ordered(o_mode, o_name, mode, name)) {
 314                         case TREE_UNORDERED:
 315                                 not_properly_sorted = 1;
 316                                 break;
 317                         case TREE_HAS_DUPS:
 318                                 has_dup_entries = 1;
 319                                 break;
 320                         default:
 321                                 break;
 322                         }
 323                 }
 324
 325                 o_mode = mode;
 326                 o_name = name;
 327                 o_sha1 = sha1;
 328         }
 329         free(item->buffer);
 330         item->buffer = NULL;
 331
 332         retval = 0;
 333         if (has_full_path) {
 334                 objwarning(&item->object, "contains full pathnames");
 335         }
 336         if (has_empty_name) {
 337                 objwarning(&item->object, "contains empty pathname");
 338         }
 339         if (has_zero_pad) {
 340                 objwarning(&item->object, "contains zero-padded file modes");
 341         }
 342         if (has_bad_modes) {
 343                 objwarning(&item->object, "contains bad file modes");
 344         }
 345         if (has_dup_entries) {
 346                 retval = objerror(&item->object, "contains duplicate file entries");
 347         }
 348         if (not_properly_sorted) {
 349                 retval = objerror(&item->object, "not properly sorted");
 350         }
 351         return retval;
 352 }
 353
 354 static int fsck_commit(struct commit *commit)
 355 {
 356         char *buffer = commit->buffer;
 357         unsigned char tree_sha1[20], sha1[20];
 358
 359         if (verbose)
 360                 fprintf(stderr, "Checking commit %s\n",
 361                         sha1_to_hex(commit->object.sha1));
 362
 363         if (memcmp(buffer, "tree ", 5))
 364                 return objerror(&commit->object, "invalid format - expected 'tree' line");
 365         if (get_sha1_hex(buffer+5, tree_sha1) || buffer[45] != '\n')
 366                 return objerror(&commit->object, "invalid 'tree' line format - bad sha1");
 367         buffer += 46;
 368         while (!memcmp(buffer, "parent ", 7)) {
 369                 if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
 370                         return objerror(&commit->object, "invalid 'parent' line format - bad sha1");
 371                 buffer += 48;
 372         }
 373         if (memcmp(buffer, "author ", 7))
 374                 return objerror(&commit->object, "invalid format - expected 'author' line");
 375         free(commit->buffer);
 376         commit->buffer = NULL;
 377         if (!commit->tree)
 378                 return objerror(&commit->object, "could not load commit's tree %s", tree_sha1);
 379         if (!commit->parents && show_root)
 380                 printf("root %s\n", sha1_to_hex(commit->object.sha1));
 381         if (!commit->date)
 382                 printf("bad commit date in %s\n",
 383                        sha1_to_hex(commit->object.sha1));
 384         return 0;
 385 }
 386
 387 static int fsck_tag(struct tag *tag)
 388 {
 389         struct object *tagged = tag->tagged;
 390
 391         if (verbose)
 392                 fprintf(stderr, "Checking tag %s\n",
 393                         sha1_to_hex(tag->object.sha1));
 394
 395         if (!tagged) {
 396                 return objerror(&tag->object, "could not load tagged object");
 397         }
 398         if (!show_tags)
 399                 return 0;
 400
 401         printf("tagged %s %s", typename(tagged->type), sha1_to_hex(tagged->sha1));
 402         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 403         return 0;
 404 }
 405
 406 static int fsck_sha1(const unsigned char *sha1)
 407 {
 408         struct object *obj = parse_object(sha1);
 409         if (!obj) {
 410                 errors_found |= ERROR_OBJECT;
 411                 return error("%s: object corrupt or missing",
 412                              sha1_to_hex(sha1));
 413         }
 414         if (obj->flags & SEEN)
 415                 return 0;
 416         obj->flags |= SEEN;
 417         if (obj->type == OBJ_BLOB)
 418                 return 0;
 419         if (obj->type == OBJ_TREE)
 420                 return fsck_tree((struct tree *) obj);
 421         if (obj->type == OBJ_COMMIT)
 422                 return fsck_commit((struct commit *) obj);
 423         if (obj->type == OBJ_TAG)
 424                 return fsck_tag((struct tag *) obj);
 425
 426         /* By now, parse_object() would've returned NULL instead. */
 427         return objerror(obj, "unknown type '%d' (internal fsck error)",
 428                         obj->type);
 429 }
 430
 431 /*
 432  * This is the sorting chunk size: make it reasonably
 433  * big so that we can sort well..
 434  */
 435 #define MAX_SHA1_ENTRIES (1024)
 436
 437 struct sha1_entry {
 438         unsigned long ino;
 439         unsigned char sha1[20];
 440 };
 441
 442 static struct {
 443         unsigned long nr;
 444         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 445 } sha1_list;
 446
 447 static int ino_compare(const void *_a, const void *_b)
 448 {
 449         const struct sha1_entry *a = _a, *b = _b;
 450         unsigned long ino1 = a->ino, ino2 = b->ino;
 451         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 452 }
 453
 454 static void fsck_sha1_list(void)
 455 {
 456         int i, nr = sha1_list.nr;
 457
 458         if (SORT_DIRENT)
 459                 qsort(sha1_list.entry, nr,
 460                       sizeof(struct sha1_entry *), ino_compare);
 461         for (i = 0; i < nr; i++) {
 462                 struct sha1_entry *entry = sha1_list.entry[i];
 463                 unsigned char *sha1 = entry->sha1;
 464
 465                 sha1_list.entry[i] = NULL;
 466                 fsck_sha1(sha1);
 467                 free(entry);
 468         }
 469         sha1_list.nr = 0;
 470 }
 471
 472 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 473 {
 474         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 475         int nr;
 476
 477         entry->ino = ino;
 478         hashcpy(entry->sha1, sha1);
 479         nr = sha1_list.nr;
 480         if (nr == MAX_SHA1_ENTRIES) {
 481                 fsck_sha1_list();
 482                 nr = 0;
 483         }
 484         sha1_list.entry[nr] = entry;
 485         sha1_list.nr = ++nr;
 486 }
 487
 488 static void fsck_dir(int i, char *path)
 489 {
 490         DIR *dir = opendir(path);
 491         struct dirent *de;
 492
 493         if (!dir)
 494                 return;
 495
 496         if (verbose)
 497                 fprintf(stderr, "Checking directory %s\n", path);
 498
 499         while ((de = readdir(dir)) != NULL) {
 500                 char name[100];
 501                 unsigned char sha1[20];
 502                 int len = strlen(de->d_name);
 503
 504                 switch (len) {
 505                 case 2:
 506                         if (de->d_name[1] != '.')
 507                                 break;
 508                 case 1:
 509                         if (de->d_name[0] != '.')
 510                                 break;
 511                         continue;
 512                 case 38:
 513                         sprintf(name, "%02x", i);
 514                         memcpy(name+2, de->d_name, len+1);
 515                         if (get_sha1_hex(name, sha1) < 0)
 516                                 break;
 517                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 518                         continue;
 519                 }
 520                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 521         }
 522         closedir(dir);
 523 }
 524
 525 static int default_refs;
 526
 527 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 528                 const char *email, unsigned long timestamp, int tz,
 529                 const char *message, void *cb_data)
 530 {
 531         struct object *obj;
 532
 533         if (verbose)
 534                 fprintf(stderr, "Checking reflog %s->%s\n",
 535                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 536
 537         if (!is_null_sha1(osha1)) {
 538                 obj = lookup_object(osha1);
 539                 if (obj) {
 540                         obj->used = 1;
 541                         mark_reachable(obj, REACHABLE);
 542                 }
 543         }
 544         obj = lookup_object(nsha1);
 545         if (obj) {
 546                 obj->used = 1;
 547                 mark_reachable(obj, REACHABLE);
 548         }
 549         return 0;
 550 }
 551
 552 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 553 {
 554         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 555         return 0;
 556 }
 557
 558 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 559 {
 560         struct object *obj;
 561
 562         obj = lookup_object(sha1);
 563         if (!obj) {
 564                 if (has_sha1_file(sha1)) {
 565                         default_refs++;
 566                         return 0; /* it is in a pack */
 567                 }
 568                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 569                 /* We'll continue with the rest despite the error.. */
 570                 return 0;
 571         }
 572         default_refs++;
 573         obj->used = 1;
 574         mark_reachable(obj, REACHABLE);
 575
 576         return 0;
 577 }
 578
 579 static void get_default_heads(void)
 580 {
 581         for_each_ref(fsck_handle_ref, NULL);
 582         if (include_reflogs)
 583                 for_each_reflog(fsck_handle_reflog, NULL);
 584
 585         /*
 586          * Not having any default heads isn't really fatal, but
 587          * it does mean that "--unreachable" no longer makes any
 588          * sense (since in this case everything will obviously
 589          * be unreachable by definition.
 590          *
 591          * Showing dangling objects is valid, though (as those
 592          * dangling objects are likely lost heads).
 593          *
 594          * So we just print a warning about it, and clear the
 595          * "show_unreachable" flag.
 596          */
 597         if (!default_refs) {
 598                 fprintf(stderr, "notice: No default references\n");
 599                 show_unreachable = 0;
 600         }
 601 }
 602
 603 static void fsck_object_dir(const char *path)
 604 {
 605         int i;
 606
 607         if (verbose)
 608                 fprintf(stderr, "Checking object directory\n");
 609
 610         for (i = 0; i < 256; i++) {
 611                 static char dir[4096];
 612                 sprintf(dir, "%s/%02x", path, i);
 613                 fsck_dir(i, dir);
 614         }
 615         fsck_sha1_list();
 616 }
 617
 618 static int fsck_head_link(void)
 619 {
 620         unsigned char sha1[20];
 621         int flag;
 622         int null_is_error = 0;
 623         const char *head_points_at = resolve_ref("HEAD", sha1, 0, &flag);
 624
 625         if (verbose)
 626                 fprintf(stderr, "Checking HEAD link\n");
 627
 628         if (!head_points_at)
 629                 return error("Invalid HEAD");
 630         if (!strcmp(head_points_at, "HEAD"))
 631                 /* detached HEAD */
 632                 null_is_error = 1;
 633         else if (prefixcmp(head_points_at, "refs/heads/"))
 634                 return error("HEAD points to something strange (%s)",
 635                              head_points_at);
 636         if (is_null_sha1(sha1)) {
 637                 if (null_is_error)
 638                         return error("HEAD: detached HEAD points at nothing");
 639                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 640                         head_points_at + 11);
 641         }
 642         return 0;
 643 }
 644
 645 static int fsck_cache_tree(struct cache_tree *it)
 646 {
 647         int i;
 648         int err = 0;
 649
 650         if (verbose)
 651                 fprintf(stderr, "Checking cache tree\n");
 652
 653         if (0 <= it->entry_count) {
 654                 struct object *obj = parse_object(it->sha1);
 655                 if (!obj) {
 656                         error("%s: invalid sha1 pointer in cache-tree",
 657                               sha1_to_hex(it->sha1));
 658                         return 1;
 659                 }
 660                 mark_reachable(obj, REACHABLE);
 661                 obj->used = 1;
 662                 if (obj->type != OBJ_TREE)
 663                         err |= objerror(obj, "non-tree in cache-tree");
 664         }
 665         for (i = 0; i < it->subtree_nr; i++)
 666                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 667         return err;
 668 }
 669
 670 static char const * const fsck_usage[] = {
 671         "git-fsck [options] [<object>...]",
 672         NULL
 673 };
 674
 675 static struct option fsck_opts[] = {
 676         OPT__VERBOSE(&verbose),
 677         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 678         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 679         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 680         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 681         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 682         OPT_BOOLEAN(0, "full", &check_full, "also consider alternate objects"),
 683         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 684         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 685                                 "write dangling objects in .git/lost-found"),
 686         OPT_END(),
 687 };
 688
 689 int cmd_fsck(int argc, const char **argv, const char *prefix)
 690 {
 691         int i, heads;
 692
 693         track_object_refs = 1;
 694         errors_found = 0;
 695
 696         argc = parse_options(argc, argv, fsck_opts, fsck_usage, 0);
 697         if (write_lost_and_found) {
 698                 check_full = 1;
 699                 include_reflogs = 0;
 700         }
 701
 702         fsck_head_link();
 703         fsck_object_dir(get_object_directory());
 704         if (check_full) {
 705                 struct alternate_object_database *alt;
 706                 struct packed_git *p;
 707                 prepare_alt_odb();
 708                 for (alt = alt_odb_list; alt; alt = alt->next) {
 709                         char namebuf[PATH_MAX];
 710                         int namelen = alt->name - alt->base;
 711                         memcpy(namebuf, alt->base, namelen);
 712                         namebuf[namelen - 1] = 0;
 713                         fsck_object_dir(namebuf);
 714                 }
 715                 prepare_packed_git();
 716                 for (p = packed_git; p; p = p->next)
 717                         /* verify gives error messages itself */
 718                         verify_pack(p, 0);
 719
 720                 for (p = packed_git; p; p = p->next) {
 721                         uint32_t j, num;
 722                         if (open_pack_index(p))
 723                                 continue;
 724                         num = p->num_objects;
 725                         for (j = 0; j < num; j++)
 726                                 fsck_sha1(nth_packed_object_sha1(p, j));
 727                 }
 728         }
 729
 730         heads = 0;
 731         for (i = 1; i < argc; i++) {
 732                 const char *arg = argv[i];
 733                 if (!get_sha1(arg, head_sha1)) {
 734                         struct object *obj = lookup_object(head_sha1);
 735
 736                         /* Error is printed by lookup_object(). */
 737                         if (!obj)
 738                                 continue;
 739
 740                         obj->used = 1;
 741                         mark_reachable(obj, REACHABLE);
 742                         heads++;
 743                         continue;
 744                 }
 745                 error("invalid parameter: expected sha1, got '%s'", arg);
 746         }
 747
 748         /*
 749          * If we've not been given any explicit head information, do the
 750          * default ones from .git/refs. We also consider the index file
 751          * in this case (ie this implies --cache).
 752          */
 753         if (!heads) {
 754                 get_default_heads();
 755                 keep_cache_objects = 1;
 756         }
 757
 758         if (keep_cache_objects) {
 759                 read_cache();
 760                 for (i = 0; i < active_nr; i++) {
 761                         unsigned int mode;
 762                         struct blob *blob;
 763                         struct object *obj;
 764
 765                         mode = ntohl(active_cache[i]->ce_mode);
 766                         if (S_ISGITLINK(mode))
 767                                 continue;
 768                         blob = lookup_blob(active_cache[i]->sha1);
 769                         if (!blob)
 770                                 continue;
 771                         obj = &blob->object;
 772                         obj->used = 1;
 773                         mark_reachable(obj, REACHABLE);
 774                 }
 775                 if (active_cache_tree)
 776                         fsck_cache_tree(active_cache_tree);
 777         }
 778
 779         check_connectivity();
 780         return errors_found;
 781 }