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         /*
  78          * The only case data is NULL or type is OBJ_ANY is when
  79          * mark_object_reachable() calls us.  All the callers of
  80          * that function has non-NULL obj hence ...
  81          */
  82         if (!obj) {
  83                 /* ... these references to parent->fld are safe here */
  84                 printf("broken link from %7s %s\n",
  85                            typename(parent->type), sha1_to_hex(parent->sha1));
  86                 printf("broken link from %7s %s\n",
  87                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
  88                 errors_found |= ERROR_REACHABLE;
  89                 return 1;
  90         }
  91
  92         if (type != OBJ_ANY && obj->type != type)
  93                 /* ... and the reference to parent is safe here */
  94                 objerror(parent, "wrong object type in link");
  95
  96         if (obj->flags & REACHABLE)
  97                 return 0;
  98         obj->flags |= REACHABLE;
  99         if (!obj->parsed) {
 100                 if (parent && !has_sha1_file(obj->sha1)) {
 101                         printf("broken link from %7s %s\n",
 102                                  typename(parent->type), sha1_to_hex(parent->sha1));
 103                         printf("              to %7s %s\n",
 104                                  typename(obj->type), sha1_to_hex(obj->sha1));
 105                         errors_found |= ERROR_REACHABLE;
 106                 }
 107                 return 1;
 108         }
 109
 110         add_object_array(obj, (void *) parent, &pending);
 111         return 0;
 112 }
 113
 114 static void mark_object_reachable(struct object *obj)
 115 {
 116         mark_object(obj, OBJ_ANY, NULL);
 117 }
 118
 119 static int traverse_one_object(struct object *obj)
 120 {
 121         int result;
 122         struct tree *tree = NULL;
 123
 124         if (obj->type == OBJ_TREE) {
 125                 obj->parsed = 0;
 126                 tree = (struct tree *)obj;
 127                 if (parse_tree(tree) < 0)
 128                         return 1; /* error already displayed */
 129         }
 130         result = fsck_walk(obj, mark_object, obj);
 131         if (tree) {
 132                 free(tree->buffer);
 133                 tree->buffer = NULL;
 134         }
 135         return result;
 136 }
 137
 138 static int traverse_reachable(void)
 139 {
 140         int result = 0;
 141         while (pending.nr) {
 142                 struct object_array_entry *entry;
 143                 struct object *obj, *parent;
 144
 145                 entry = pending.objects + --pending.nr;
 146                 obj = entry->item;
 147                 parent = (struct object *) entry->name;
 148                 result |= traverse_one_object(obj);
 149         }
 150         return !!result;
 151 }
 152
 153 static int mark_used(struct object *obj, int type, void *data)
 154 {
 155         if (!obj)
 156                 return 1;
 157         obj->used = 1;
 158         return 0;
 159 }
 160
 161 /*
 162  * Check a single reachable object
 163  */
 164 static void check_reachable_object(struct object *obj)
 165 {
 166         /*
 167          * We obviously want the object to be parsed,
 168          * except if it was in a pack-file and we didn't
 169          * do a full fsck
 170          */
 171         if (!obj->parsed) {
 172                 if (has_sha1_pack(obj->sha1))
 173                         return; /* it is in pack - forget about it */
 174                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 175                 errors_found |= ERROR_REACHABLE;
 176                 return;
 177         }
 178 }
 179
 180 /*
 181  * Check a single unreachable object
 182  */
 183 static void check_unreachable_object(struct object *obj)
 184 {
 185         /*
 186          * Missing unreachable object? Ignore it. It's not like
 187          * we miss it (since it can't be reached), nor do we want
 188          * to complain about it being unreachable (since it does
 189          * not exist).
 190          */
 191         if (!obj->parsed)
 192                 return;
 193
 194         /*
 195          * Unreachable object that exists? Show it if asked to,
 196          * since this is something that is prunable.
 197          */
 198         if (show_unreachable) {
 199                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 200                 return;
 201         }
 202
 203         /*
 204          * "!used" means that nothing at all points to it, including
 205          * other unreachable objects. In other words, it's the "tip"
 206          * of some set of unreachable objects, usually a commit that
 207          * got dropped.
 208          *
 209          * Such starting points are more interesting than some random
 210          * set of unreachable objects, so we show them even if the user
 211          * hasn't asked for _all_ unreachable objects. If you have
 212          * deleted a branch by mistake, this is a prime candidate to
 213          * start looking at, for example.
 214          */
 215         if (!obj->used) {
 216                 printf("dangling %s %s\n", typename(obj->type),
 217                        sha1_to_hex(obj->sha1));
 218                 if (write_lost_and_found) {
 219                         char *filename = git_path("lost-found/%s/%s",
 220                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 221                                 sha1_to_hex(obj->sha1));
 222                         FILE *f;
 223
 224                         if (safe_create_leading_directories(filename)) {
 225                                 error("Could not create lost-found");
 226                                 return;
 227                         }
 228                         if (!(f = fopen(filename, "w")))
 229                                 die_errno("Could not open '%s'", filename);
 230                         if (obj->type == OBJ_BLOB) {
 231                                 enum object_type type;
 232                                 unsigned long size;
 233                                 char *buf = read_sha1_file(obj->sha1,
 234                                                 &type, &size);
 235                                 if (buf) {
 236                                         if (fwrite(buf, size, 1, f) != 1)
 237                                                 die_errno("Could not write '%s'",
 238                                                           filename);
 239                                         free(buf);
 240                                 }
 241                         } else
 242                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 243                         if (fclose(f))
 244                                 die_errno("Could not finish '%s'",
 245                                           filename);
 246                 }
 247                 return;
 248         }
 249
 250         /*
 251          * Otherwise? It's there, it's unreachable, and some other unreachable
 252          * object points to it. Ignore it - it's not interesting, and we showed
 253          * all the interesting cases above.
 254          */
 255 }
 256
 257 static void check_object(struct object *obj)
 258 {
 259         if (verbose)
 260                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 261
 262         if (obj->flags & REACHABLE)
 263                 check_reachable_object(obj);
 264         else
 265                 check_unreachable_object(obj);
 266 }
 267
 268 static void check_connectivity(void)
 269 {
 270         int i, max;
 271
 272         /* Traverse the pending reachable objects */
 273         traverse_reachable();
 274
 275         /* Look up all the requirements, warn about missing objects.. */
 276         max = get_max_object_index();
 277         if (verbose)
 278                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 279
 280         for (i = 0; i < max; i++) {
 281                 struct object *obj = get_indexed_object(i);
 282
 283                 if (obj)
 284                         check_object(obj);
 285         }
 286 }
 287
 288 static int fsck_sha1(const unsigned char *sha1)
 289 {
 290         struct object *obj = parse_object(sha1);
 291         if (!obj) {
 292                 errors_found |= ERROR_OBJECT;
 293                 return error("%s: object corrupt or missing",
 294                              sha1_to_hex(sha1));
 295         }
 296         if (obj->flags & SEEN)
 297                 return 0;
 298         obj->flags |= SEEN;
 299
 300         if (verbose)
 301                 fprintf(stderr, "Checking %s %s\n",
 302                         typename(obj->type), sha1_to_hex(obj->sha1));
 303
 304         if (fsck_walk(obj, mark_used, NULL))
 305                 objerror(obj, "broken links");
 306         if (fsck_object(obj, check_strict, fsck_error_func))
 307                 return -1;
 308
 309         if (obj->type == OBJ_TREE) {
 310                 struct tree *item = (struct tree *) obj;
 311
 312                 free(item->buffer);
 313                 item->buffer = NULL;
 314         }
 315
 316         if (obj->type == OBJ_COMMIT) {
 317                 struct commit *commit = (struct commit *) obj;
 318
 319                 free(commit->buffer);
 320                 commit->buffer = NULL;
 321
 322                 if (!commit->parents && show_root)
 323                         printf("root %s\n", sha1_to_hex(commit->object.sha1));
 324         }
 325
 326         if (obj->type == OBJ_TAG) {
 327                 struct tag *tag = (struct tag *) obj;
 328
 329                 if (show_tags && tag->tagged) {
 330                         printf("tagged %s %s", typename(tag->tagged->type), sha1_to_hex(tag->tagged->sha1));
 331                         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 332                 }
 333         }
 334
 335         return 0;
 336 }
 337
 338 /*
 339  * This is the sorting chunk size: make it reasonably
 340  * big so that we can sort well..
 341  */
 342 #define MAX_SHA1_ENTRIES (1024)
 343
 344 struct sha1_entry {
 345         unsigned long ino;
 346         unsigned char sha1[20];
 347 };
 348
 349 static struct {
 350         unsigned long nr;
 351         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 352 } sha1_list;
 353
 354 static int ino_compare(const void *_a, const void *_b)
 355 {
 356         const struct sha1_entry *a = _a, *b = _b;
 357         unsigned long ino1 = a->ino, ino2 = b->ino;
 358         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 359 }
 360
 361 static void fsck_sha1_list(void)
 362 {
 363         int i, nr = sha1_list.nr;
 364
 365         if (SORT_DIRENT)
 366                 qsort(sha1_list.entry, nr,
 367                       sizeof(struct sha1_entry *), ino_compare);
 368         for (i = 0; i < nr; i++) {
 369                 struct sha1_entry *entry = sha1_list.entry[i];
 370                 unsigned char *sha1 = entry->sha1;
 371
 372                 sha1_list.entry[i] = NULL;
 373                 fsck_sha1(sha1);
 374                 free(entry);
 375         }
 376         sha1_list.nr = 0;
 377 }
 378
 379 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 380 {
 381         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 382         int nr;
 383
 384         entry->ino = ino;
 385         hashcpy(entry->sha1, sha1);
 386         nr = sha1_list.nr;
 387         if (nr == MAX_SHA1_ENTRIES) {
 388                 fsck_sha1_list();
 389                 nr = 0;
 390         }
 391         sha1_list.entry[nr] = entry;
 392         sha1_list.nr = ++nr;
 393 }
 394
 395 static void fsck_dir(int i, char *path)
 396 {
 397         DIR *dir = opendir(path);
 398         struct dirent *de;
 399
 400         if (!dir)
 401                 return;
 402
 403         if (verbose)
 404                 fprintf(stderr, "Checking directory %s\n", path);
 405
 406         while ((de = readdir(dir)) != NULL) {
 407                 char name[100];
 408                 unsigned char sha1[20];
 409
 410                 if (is_dot_or_dotdot(de->d_name))
 411                         continue;
 412                 if (strlen(de->d_name) == 38) {
 413                         sprintf(name, "%02x", i);
 414                         memcpy(name+2, de->d_name, 39);
 415                         if (get_sha1_hex(name, sha1) < 0)
 416                                 break;
 417                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 418                         continue;
 419                 }
 420                 if (!prefixcmp(de->d_name, "tmp_obj_"))
 421                         continue;
 422                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 423         }
 424         closedir(dir);
 425 }
 426
 427 static int default_refs;
 428
 429 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 430                 const char *email, unsigned long timestamp, int tz,
 431                 const char *message, void *cb_data)
 432 {
 433         struct object *obj;
 434
 435         if (verbose)
 436                 fprintf(stderr, "Checking reflog %s->%s\n",
 437                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 438
 439         if (!is_null_sha1(osha1)) {
 440                 obj = lookup_object(osha1);
 441                 if (obj) {
 442                         obj->used = 1;
 443                         mark_object_reachable(obj);
 444                 }
 445         }
 446         obj = lookup_object(nsha1);
 447         if (obj) {
 448                 obj->used = 1;
 449                 mark_object_reachable(obj);
 450         }
 451         return 0;
 452 }
 453
 454 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 455 {
 456         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 457         return 0;
 458 }
 459
 460 static int is_branch(const char *refname)
 461 {
 462         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
 463 }
 464
 465 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 466 {
 467         struct object *obj;
 468
 469         obj = parse_object(sha1);
 470         if (!obj) {
 471                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 472                 /* We'll continue with the rest despite the error.. */
 473                 return 0;
 474         }
 475         if (obj->type != OBJ_COMMIT && is_branch(refname))
 476                 error("%s: not a commit", refname);
 477         default_refs++;
 478         obj->used = 1;
 479         mark_object_reachable(obj);
 480
 481         return 0;
 482 }
 483
 484 static void get_default_heads(void)
 485 {
 486         if (head_points_at && !is_null_sha1(head_sha1))
 487                 fsck_handle_ref("HEAD", head_sha1, 0, NULL);
 488         for_each_ref(fsck_handle_ref, NULL);
 489         if (include_reflogs)
 490                 for_each_reflog(fsck_handle_reflog, NULL);
 491
 492         /*
 493          * Not having any default heads isn't really fatal, but
 494          * it does mean that "--unreachable" no longer makes any
 495          * sense (since in this case everything will obviously
 496          * be unreachable by definition.
 497          *
 498          * Showing dangling objects is valid, though (as those
 499          * dangling objects are likely lost heads).
 500          *
 501          * So we just print a warning about it, and clear the
 502          * "show_unreachable" flag.
 503          */
 504         if (!default_refs) {
 505                 fprintf(stderr, "notice: No default references\n");
 506                 show_unreachable = 0;
 507         }
 508 }
 509
 510 static void fsck_object_dir(const char *path)
 511 {
 512         int i;
 513
 514         if (verbose)
 515                 fprintf(stderr, "Checking object directory\n");
 516
 517         for (i = 0; i < 256; i++) {
 518                 static char dir[4096];
 519                 sprintf(dir, "%s/%02x", path, i);
 520                 fsck_dir(i, dir);
 521         }
 522         fsck_sha1_list();
 523 }
 524
 525 static int fsck_head_link(void)
 526 {
 527         int flag;
 528         int null_is_error = 0;
 529
 530         if (verbose)
 531                 fprintf(stderr, "Checking HEAD link\n");
 532
 533         head_points_at = resolve_ref("HEAD", head_sha1, 0, &flag);
 534         if (!head_points_at)
 535                 return error("Invalid HEAD");
 536         if (!strcmp(head_points_at, "HEAD"))
 537                 /* detached HEAD */
 538                 null_is_error = 1;
 539         else if (prefixcmp(head_points_at, "refs/heads/"))
 540                 return error("HEAD points to something strange (%s)",
 541                              head_points_at);
 542         if (is_null_sha1(head_sha1)) {
 543                 if (null_is_error)
 544                         return error("HEAD: detached HEAD points at nothing");
 545                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 546                         head_points_at + 11);
 547         }
 548         return 0;
 549 }
 550
 551 static int fsck_cache_tree(struct cache_tree *it)
 552 {
 553         int i;
 554         int err = 0;
 555
 556         if (verbose)
 557                 fprintf(stderr, "Checking cache tree\n");
 558
 559         if (0 <= it->entry_count) {
 560                 struct object *obj = parse_object(it->sha1);
 561                 if (!obj) {
 562                         error("%s: invalid sha1 pointer in cache-tree",
 563                               sha1_to_hex(it->sha1));
 564                         return 1;
 565                 }
 566                 obj->used = 1;
 567                 mark_object_reachable(obj);
 568                 if (obj->type != OBJ_TREE)
 569                         err |= objerror(obj, "non-tree in cache-tree");
 570         }
 571         for (i = 0; i < it->subtree_nr; i++)
 572                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 573         return err;
 574 }
 575
 576 static char const * const fsck_usage[] = {
 577         "git fsck [options] [<object>...]",
 578         NULL
 579 };
 580
 581 static struct option fsck_opts[] = {
 582         OPT__VERBOSE(&verbose, "be verbose"),
 583         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 584         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 585         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 586         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 587         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 588         OPT_BOOLEAN(0, "full", &check_full, "also consider packs and alternate objects"),
 589         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 590         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 591                                 "write dangling objects in .git/lost-found"),
 592         OPT_END(),
 593 };
 594
 595 int cmd_fsck(int argc, const char **argv, const char *prefix)
 596 {
 597         int i, heads;
 598         struct alternate_object_database *alt;
 599
 600         errors_found = 0;
 601         read_replace_refs = 0;
 602
 603         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
 604         if (write_lost_and_found) {
 605                 check_full = 1;
 606                 include_reflogs = 0;
 607         }
 608
 609         fsck_head_link();
 610         fsck_object_dir(get_object_directory());
 611
 612         prepare_alt_odb();
 613         for (alt = alt_odb_list; alt; alt = alt->next) {
 614                 char namebuf[PATH_MAX];
 615                 int namelen = alt->name - alt->base;
 616                 memcpy(namebuf, alt->base, namelen);
 617                 namebuf[namelen - 1] = 0;
 618                 fsck_object_dir(namebuf);
 619         }
 620
 621         if (check_full) {
 622                 struct packed_git *p;
 623
 624                 prepare_packed_git();
 625                 for (p = packed_git; p; p = p->next)
 626                         /* verify gives error messages itself */
 627                         verify_pack(p);
 628
 629                 for (p = packed_git; p; p = p->next) {
 630                         uint32_t j, num;
 631                         if (open_pack_index(p))
 632                                 continue;
 633                         num = p->num_objects;
 634                         for (j = 0; j < num; j++)
 635                                 fsck_sha1(nth_packed_object_sha1(p, j));
 636                 }
 637         }
 638
 639         heads = 0;
 640         for (i = 0; i < argc; i++) {
 641                 const char *arg = argv[i];
 642                 unsigned char sha1[20];
 643                 if (!get_sha1(arg, sha1)) {
 644                         struct object *obj = lookup_object(sha1);
 645
 646                         /* Error is printed by lookup_object(). */
 647                         if (!obj)
 648                                 continue;
 649
 650                         obj->used = 1;
 651                         mark_object_reachable(obj);
 652                         heads++;
 653                         continue;
 654                 }
 655                 error("invalid parameter: expected sha1, got '%s'", arg);
 656         }
 657
 658         /*
 659          * If we've not been given any explicit head information, do the
 660          * default ones from .git/refs. We also consider the index file
 661          * in this case (ie this implies --cache).
 662          */
 663         if (!heads) {
 664                 get_default_heads();
 665                 keep_cache_objects = 1;
 666         }
 667
 668         if (keep_cache_objects) {
 669                 read_cache();
 670                 for (i = 0; i < active_nr; i++) {
 671                         unsigned int mode;
 672                         struct blob *blob;
 673                         struct object *obj;
 674
 675                         mode = active_cache[i]->ce_mode;
 676                         if (S_ISGITLINK(mode))
 677                                 continue;
 678                         blob = lookup_blob(active_cache[i]->sha1);
 679                         if (!blob)
 680                                 continue;
 681                         obj = &blob->object;
 682                         obj->used = 1;
 683                         mark_object_reachable(obj);
 684                 }
 685                 if (active_cache_tree)
 686                         fsck_cache_tree(active_cache_tree);
 687         }
 688
 689         check_connectivity();
 690         return errors_found;
 691 }