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 "fsck.h"
  12 #include "parse-options.h"
  13 #include "dir.h"
  14
  15 #define REACHABLE 0x0001
  16 #define SEEN      0x0002
  17
  18 static int show_root;
  19 static int show_tags;
  20 static int show_unreachable;
  21 static int include_reflogs = 1;
  22 static int check_full = 1;
  23 static int check_strict;
  24 static int keep_cache_objects;
  25 static unsigned char head_sha1[20];
  26 static const char *head_points_at;
  27 static int errors_found;
  28 static int write_lost_and_found;
  29 static int verbose;
  30 #define ERROR_OBJECT 01
  31 #define ERROR_REACHABLE 02
  32
  33 #ifdef NO_D_INO_IN_DIRENT
  34 #define SORT_DIRENT 0
  35 #define DIRENT_SORT_HINT(de) 0
  36 #else
  37 #define SORT_DIRENT 1
  38 #define DIRENT_SORT_HINT(de) ((de)->d_ino)
  39 #endif
  40
  41 static void objreport(struct object *obj, const char *severity,
  42                       const char *err, va_list params)
  43 {
  44         fprintf(stderr, "%s in %s %s: ",
  45                 severity, typename(obj->type), sha1_to_hex(obj->sha1));
  46         vfprintf(stderr, err, params);
  47         fputs("\n", stderr);
  48 }
  49
  50 __attribute__((format (printf, 2, 3)))
  51 static int objerror(struct object *obj, const char *err, ...)
  52 {
  53         va_list params;
  54         va_start(params, err);
  55         errors_found |= ERROR_OBJECT;
  56         objreport(obj, "error", err, params);
  57         va_end(params);
  58         return -1;
  59 }
  60
  61 __attribute__((format (printf, 3, 4)))
  62 static int fsck_error_func(struct object *obj, int type, const char *err, ...)
  63 {
  64         va_list params;
  65         va_start(params, err);
  66         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", err, params);
  67         va_end(params);
  68         return (type == FSCK_WARN) ? 0 : 1;
  69 }
  70
  71 static struct object_array pending;
  72
  73 static int mark_object(struct object *obj, int type, void *data)
  74 {
  75         struct object *parent = data;
  76
  77         if (!obj) {
  78                 printf("broken link from %7s %s\n",
  79                            typename(parent->type), sha1_to_hex(parent->sha1));
  80                 printf("broken link from %7s %s\n",
  81                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
  82                 errors_found |= ERROR_REACHABLE;
  83                 return 1;
  84         }
  85
  86         if (type != OBJ_ANY && obj->type != type)
  87                 objerror(parent, "wrong object type in link");
  88
  89         if (obj->flags & REACHABLE)
  90                 return 0;
  91         obj->flags |= REACHABLE;
  92         if (!obj->parsed) {
  93                 if (parent && !has_sha1_file(obj->sha1)) {
  94                         printf("broken link from %7s %s\n",
  95                                  typename(parent->type), sha1_to_hex(parent->sha1));
  96                         printf("              to %7s %s\n",
  97                                  typename(obj->type), sha1_to_hex(obj->sha1));
  98                         errors_found |= ERROR_REACHABLE;
  99                 }
 100                 return 1;
 101         }
 102
 103         add_object_array(obj, (void *) parent, &pending);
 104         return 0;
 105 }
 106
 107 static void mark_object_reachable(struct object *obj)
 108 {
 109         mark_object(obj, OBJ_ANY, NULL);
 110 }
 111
 112 static int traverse_one_object(struct object *obj, struct object *parent)
 113 {
 114         int result;
 115         struct tree *tree = NULL;
 116
 117         if (obj->type == OBJ_TREE) {
 118                 obj->parsed = 0;
 119                 tree = (struct tree *)obj;
 120                 if (parse_tree(tree) < 0)
 121                         return 1; /* error already displayed */
 122         }
 123         result = fsck_walk(obj, mark_object, obj);
 124         if (tree) {
 125                 free(tree->buffer);
 126                 tree->buffer = NULL;
 127         }
 128         return result;
 129 }
 130
 131 static int traverse_reachable(void)
 132 {
 133         int result = 0;
 134         while (pending.nr) {
 135                 struct object_array_entry *entry;
 136                 struct object *obj, *parent;
 137
 138                 entry = pending.objects + --pending.nr;
 139                 obj = entry->item;
 140                 parent = (struct object *) entry->name;
 141                 result |= traverse_one_object(obj, parent);
 142         }
 143         return !!result;
 144 }
 145
 146 static int mark_used(struct object *obj, int type, void *data)
 147 {
 148         if (!obj)
 149                 return 1;
 150         obj->used = 1;
 151         return 0;
 152 }
 153
 154 /*
 155  * Check a single reachable object
 156  */
 157 static void check_reachable_object(struct object *obj)
 158 {
 159         /*
 160          * We obviously want the object to be parsed,
 161          * except if it was in a pack-file and we didn't
 162          * do a full fsck
 163          */
 164         if (!obj->parsed) {
 165                 if (has_sha1_pack(obj->sha1))
 166                         return; /* it is in pack - forget about it */
 167                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 168                 errors_found |= ERROR_REACHABLE;
 169                 return;
 170         }
 171 }
 172
 173 /*
 174  * Check a single unreachable object
 175  */
 176 static void check_unreachable_object(struct object *obj)
 177 {
 178         /*
 179          * Missing unreachable object? Ignore it. It's not like
 180          * we miss it (since it can't be reached), nor do we want
 181          * to complain about it being unreachable (since it does
 182          * not exist).
 183          */
 184         if (!obj->parsed)
 185                 return;
 186
 187         /*
 188          * Unreachable object that exists? Show it if asked to,
 189          * since this is something that is prunable.
 190          */
 191         if (show_unreachable) {
 192                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 193                 return;
 194         }
 195
 196         /*
 197          * "!used" means that nothing at all points to it, including
 198          * other unreachable objects. In other words, it's the "tip"
 199          * of some set of unreachable objects, usually a commit that
 200          * got dropped.
 201          *
 202          * Such starting points are more interesting than some random
 203          * set of unreachable objects, so we show them even if the user
 204          * hasn't asked for _all_ unreachable objects. If you have
 205          * deleted a branch by mistake, this is a prime candidate to
 206          * start looking at, for example.
 207          */
 208         if (!obj->used) {
 209                 printf("dangling %s %s\n", typename(obj->type),
 210                        sha1_to_hex(obj->sha1));
 211                 if (write_lost_and_found) {
 212                         char *filename = git_path("lost-found/%s/%s",
 213                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 214                                 sha1_to_hex(obj->sha1));
 215                         FILE *f;
 216
 217                         if (safe_create_leading_directories(filename)) {
 218                                 error("Could not create lost-found");
 219                                 return;
 220                         }
 221                         if (!(f = fopen(filename, "w")))
 222                                 die_errno("Could not open '%s'", filename);
 223                         if (obj->type == OBJ_BLOB) {
 224                                 enum object_type type;
 225                                 unsigned long size;
 226                                 char *buf = read_sha1_file(obj->sha1,
 227                                                 &type, &size);
 228                                 if (buf) {
 229                                         if (fwrite(buf, size, 1, f) != 1)
 230                                                 die_errno("Could not write '%s'",
 231                                                           filename);
 232                                         free(buf);
 233                                 }
 234                         } else
 235                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 236                         if (fclose(f))
 237                                 die_errno("Could not finish '%s'",
 238                                           filename);
 239                 }
 240                 return;
 241         }
 242
 243         /*
 244          * Otherwise? It's there, it's unreachable, and some other unreachable
 245          * object points to it. Ignore it - it's not interesting, and we showed
 246          * all the interesting cases above.
 247          */
 248 }
 249
 250 static void check_object(struct object *obj)
 251 {
 252         if (verbose)
 253                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 254
 255         if (obj->flags & REACHABLE)
 256                 check_reachable_object(obj);
 257         else
 258                 check_unreachable_object(obj);
 259 }
 260
 261 static void check_connectivity(void)
 262 {
 263         int i, max;
 264
 265         /* Traverse the pending reachable objects */
 266         traverse_reachable();
 267
 268         /* Look up all the requirements, warn about missing objects.. */
 269         max = get_max_object_index();
 270         if (verbose)
 271                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 272
 273         for (i = 0; i < max; i++) {
 274                 struct object *obj = get_indexed_object(i);
 275
 276                 if (obj)
 277                         check_object(obj);
 278         }
 279 }
 280
 281 static int fsck_sha1(const unsigned char *sha1)
 282 {
 283         struct object *obj = parse_object(sha1);
 284         if (!obj) {
 285                 errors_found |= ERROR_OBJECT;
 286                 return error("%s: object corrupt or missing",
 287                              sha1_to_hex(sha1));
 288         }
 289         if (obj->flags & SEEN)
 290                 return 0;
 291         obj->flags |= SEEN;
 292
 293         if (verbose)
 294                 fprintf(stderr, "Checking %s %s\n",
 295                         typename(obj->type), sha1_to_hex(obj->sha1));
 296
 297         if (fsck_walk(obj, mark_used, NULL))
 298                 objerror(obj, "broken links");
 299         if (fsck_object(obj, check_strict, fsck_error_func))
 300                 return -1;
 301
 302         if (obj->type == OBJ_TREE) {
 303                 struct tree *item = (struct tree *) obj;
 304
 305                 free(item->buffer);
 306                 item->buffer = NULL;
 307         }
 308
 309         if (obj->type == OBJ_COMMIT) {
 310                 struct commit *commit = (struct commit *) obj;
 311
 312                 free(commit->buffer);
 313                 commit->buffer = NULL;
 314
 315                 if (!commit->parents && show_root)
 316                         printf("root %s\n", sha1_to_hex(commit->object.sha1));
 317         }
 318
 319         if (obj->type == OBJ_TAG) {
 320                 struct tag *tag = (struct tag *) obj;
 321
 322                 if (show_tags && tag->tagged) {
 323                         printf("tagged %s %s", typename(tag->tagged->type), sha1_to_hex(tag->tagged->sha1));
 324                         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 325                 }
 326         }
 327
 328         return 0;
 329 }
 330
 331 /*
 332  * This is the sorting chunk size: make it reasonably
 333  * big so that we can sort well..
 334  */
 335 #define MAX_SHA1_ENTRIES (1024)
 336
 337 struct sha1_entry {
 338         unsigned long ino;
 339         unsigned char sha1[20];
 340 };
 341
 342 static struct {
 343         unsigned long nr;
 344         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 345 } sha1_list;
 346
 347 static int ino_compare(const void *_a, const void *_b)
 348 {
 349         const struct sha1_entry *a = _a, *b = _b;
 350         unsigned long ino1 = a->ino, ino2 = b->ino;
 351         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 352 }
 353
 354 static void fsck_sha1_list(void)
 355 {
 356         int i, nr = sha1_list.nr;
 357
 358         if (SORT_DIRENT)
 359                 qsort(sha1_list.entry, nr,
 360                       sizeof(struct sha1_entry *), ino_compare);
 361         for (i = 0; i < nr; i++) {
 362                 struct sha1_entry *entry = sha1_list.entry[i];
 363                 unsigned char *sha1 = entry->sha1;
 364
 365                 sha1_list.entry[i] = NULL;
 366                 fsck_sha1(sha1);
 367                 free(entry);
 368         }
 369         sha1_list.nr = 0;
 370 }
 371
 372 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 373 {
 374         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 375         int nr;
 376
 377         entry->ino = ino;
 378         hashcpy(entry->sha1, sha1);
 379         nr = sha1_list.nr;
 380         if (nr == MAX_SHA1_ENTRIES) {
 381                 fsck_sha1_list();
 382                 nr = 0;
 383         }
 384         sha1_list.entry[nr] = entry;
 385         sha1_list.nr = ++nr;
 386 }
 387
 388 static void fsck_dir(int i, char *path)
 389 {
 390         DIR *dir = opendir(path);
 391         struct dirent *de;
 392
 393         if (!dir)
 394                 return;
 395
 396         if (verbose)
 397                 fprintf(stderr, "Checking directory %s\n", path);
 398
 399         while ((de = readdir(dir)) != NULL) {
 400                 char name[100];
 401                 unsigned char sha1[20];
 402
 403                 if (is_dot_or_dotdot(de->d_name))
 404                         continue;
 405                 if (strlen(de->d_name) == 38) {
 406                         sprintf(name, "%02x", i);
 407                         memcpy(name+2, de->d_name, 39);
 408                         if (get_sha1_hex(name, sha1) < 0)
 409                                 break;
 410                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 411                         continue;
 412                 }
 413                 if (!prefixcmp(de->d_name, "tmp_obj_"))
 414                         continue;
 415                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 416         }
 417         closedir(dir);
 418 }
 419
 420 static int default_refs;
 421
 422 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 423                 const char *email, unsigned long timestamp, int tz,
 424                 const char *message, void *cb_data)
 425 {
 426         struct object *obj;
 427
 428         if (verbose)
 429                 fprintf(stderr, "Checking reflog %s->%s\n",
 430                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 431
 432         if (!is_null_sha1(osha1)) {
 433                 obj = lookup_object(osha1);
 434                 if (obj) {
 435                         obj->used = 1;
 436                         mark_object_reachable(obj);
 437                 }
 438         }
 439         obj = lookup_object(nsha1);
 440         if (obj) {
 441                 obj->used = 1;
 442                 mark_object_reachable(obj);
 443         }
 444         return 0;
 445 }
 446
 447 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 448 {
 449         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 450         return 0;
 451 }
 452
 453 static int is_branch(const char *refname)
 454 {
 455         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
 456 }
 457
 458 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 459 {
 460         struct object *obj;
 461
 462         obj = parse_object(sha1);
 463         if (!obj) {
 464                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 465                 /* We'll continue with the rest despite the error.. */
 466                 return 0;
 467         }
 468         if (obj->type != OBJ_COMMIT && is_branch(refname))
 469                 error("%s: not a commit", refname);
 470         default_refs++;
 471         obj->used = 1;
 472         mark_object_reachable(obj);
 473
 474         return 0;
 475 }
 476
 477 static void get_default_heads(void)
 478 {
 479         if (head_points_at && !is_null_sha1(head_sha1))
 480                 fsck_handle_ref("HEAD", head_sha1, 0, NULL);
 481         for_each_ref(fsck_handle_ref, NULL);
 482         if (include_reflogs)
 483                 for_each_reflog(fsck_handle_reflog, NULL);
 484
 485         /*
 486          * Not having any default heads isn't really fatal, but
 487          * it does mean that "--unreachable" no longer makes any
 488          * sense (since in this case everything will obviously
 489          * be unreachable by definition.
 490          *
 491          * Showing dangling objects is valid, though (as those
 492          * dangling objects are likely lost heads).
 493          *
 494          * So we just print a warning about it, and clear the
 495          * "show_unreachable" flag.
 496          */
 497         if (!default_refs) {
 498                 fprintf(stderr, "notice: No default references\n");
 499                 show_unreachable = 0;
 500         }
 501 }
 502
 503 static void fsck_object_dir(const char *path)
 504 {
 505         int i;
 506
 507         if (verbose)
 508                 fprintf(stderr, "Checking object directory\n");
 509
 510         for (i = 0; i < 256; i++) {
 511                 static char dir[4096];
 512                 sprintf(dir, "%s/%02x", path, i);
 513                 fsck_dir(i, dir);
 514         }
 515         fsck_sha1_list();
 516 }
 517
 518 static int fsck_head_link(void)
 519 {
 520         int flag;
 521         int null_is_error = 0;
 522
 523         if (verbose)
 524                 fprintf(stderr, "Checking HEAD link\n");
 525
 526         head_points_at = resolve_ref("HEAD", head_sha1, 0, &flag);
 527         if (!head_points_at)
 528                 return error("Invalid HEAD");
 529         if (!strcmp(head_points_at, "HEAD"))
 530                 /* detached HEAD */
 531                 null_is_error = 1;
 532         else if (prefixcmp(head_points_at, "refs/heads/"))
 533                 return error("HEAD points to something strange (%s)",
 534                              head_points_at);
 535         if (is_null_sha1(head_sha1)) {
 536                 if (null_is_error)
 537                         return error("HEAD: detached HEAD points at nothing");
 538                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 539                         head_points_at + 11);
 540         }
 541         return 0;
 542 }
 543
 544 static int fsck_cache_tree(struct cache_tree *it)
 545 {
 546         int i;
 547         int err = 0;
 548
 549         if (verbose)
 550                 fprintf(stderr, "Checking cache tree\n");
 551
 552         if (0 <= it->entry_count) {
 553                 struct object *obj = parse_object(it->sha1);
 554                 if (!obj) {
 555                         error("%s: invalid sha1 pointer in cache-tree",
 556                               sha1_to_hex(it->sha1));
 557                         return 1;
 558                 }
 559                 mark_object_reachable(obj);
 560                 obj->used = 1;
 561                 if (obj->type != OBJ_TREE)
 562                         err |= objerror(obj, "non-tree in cache-tree");
 563         }
 564         for (i = 0; i < it->subtree_nr; i++)
 565                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 566         return err;
 567 }
 568
 569 static char const * const fsck_usage[] = {
 570         "git fsck [options] [<object>...]",
 571         NULL
 572 };
 573
 574 static struct option fsck_opts[] = {
 575         OPT__VERBOSE(&verbose),
 576         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 577         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 578         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 579         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 580         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 581         OPT_BOOLEAN(0, "full", &check_full, "also consider packs and alternate objects"),
 582         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 583         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 584                                 "write dangling objects in .git/lost-found"),
 585         OPT_END(),
 586 };
 587
 588 int cmd_fsck(int argc, const char **argv, const char *prefix)
 589 {
 590         int i, heads;
 591         struct alternate_object_database *alt;
 592
 593         errors_found = 0;
 594         read_replace_refs = 0;
 595
 596         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
 597         if (write_lost_and_found) {
 598                 check_full = 1;
 599                 include_reflogs = 0;
 600         }
 601
 602         fsck_head_link();
 603         fsck_object_dir(get_object_directory());
 604
 605         prepare_alt_odb();
 606         for (alt = alt_odb_list; alt; alt = alt->next) {
 607                 char namebuf[PATH_MAX];
 608                 int namelen = alt->name - alt->base;
 609                 memcpy(namebuf, alt->base, namelen);
 610                 namebuf[namelen - 1] = 0;
 611                 fsck_object_dir(namebuf);
 612         }
 613
 614         if (check_full) {
 615                 struct packed_git *p;
 616
 617                 prepare_packed_git();
 618                 for (p = packed_git; p; p = p->next)
 619                         /* verify gives error messages itself */
 620                         verify_pack(p);
 621
 622                 for (p = packed_git; p; p = p->next) {
 623                         uint32_t j, num;
 624                         if (open_pack_index(p))
 625                                 continue;
 626                         num = p->num_objects;
 627                         for (j = 0; j < num; j++)
 628                                 fsck_sha1(nth_packed_object_sha1(p, j));
 629                 }
 630         }
 631
 632         heads = 0;
 633         for (i = 0; i < argc; i++) {
 634                 const char *arg = argv[i];
 635                 unsigned char sha1[20];
 636                 if (!get_sha1(arg, sha1)) {
 637                         struct object *obj = lookup_object(sha1);
 638
 639                         /* Error is printed by lookup_object(). */
 640                         if (!obj)
 641                                 continue;
 642
 643                         obj->used = 1;
 644                         mark_object_reachable(obj);
 645                         heads++;
 646                         continue;
 647                 }
 648                 error("invalid parameter: expected sha1, got '%s'", arg);
 649         }
 650
 651         /*
 652          * If we've not been given any explicit head information, do the
 653          * default ones from .git/refs. We also consider the index file
 654          * in this case (ie this implies --cache).
 655          */
 656         if (!heads) {
 657                 get_default_heads();
 658                 keep_cache_objects = 1;
 659         }
 660
 661         if (keep_cache_objects) {
 662                 read_cache();
 663                 for (i = 0; i < active_nr; i++) {
 664                         unsigned int mode;
 665                         struct blob *blob;
 666                         struct object *obj;
 667
 668                         mode = active_cache[i]->ce_mode;
 669                         if (S_ISGITLINK(mode))
 670                                 continue;
 671                         blob = lookup_blob(active_cache[i]->sha1);
 672                         if (!blob)
 673                                 continue;
 674                         obj = &blob->object;
 675                         obj->used = 1;
 676                         mark_object_reachable(obj);
 677                 }
 678                 if (active_cache_tree)
 679                         fsck_cache_tree(active_cache_tree);
 680         }
 681
 682         check_connectivity();
 683         return errors_found;
 684 }