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