builtin-fsck.c

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