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;
 144
 145                 entry = pending.objects + --pending.nr;
 146                 obj = entry->item;
 147                 result |= traverse_one_object(obj);
 148         }
 149         return !!result;
 150 }
 151
 152 static int mark_used(struct object *obj, int type, void *data)
 153 {
 154         if (!obj)
 155                 return 1;
 156         obj->used = 1;
 157         return 0;
 158 }
 159
 160 /*
 161  * Check a single reachable object
 162  */
 163 static void check_reachable_object(struct object *obj)
 164 {
 165         /*
 166          * We obviously want the object to be parsed,
 167          * except if it was in a pack-file and we didn't
 168          * do a full fsck
 169          */
 170         if (!obj->parsed) {
 171                 if (has_sha1_pack(obj->sha1))
 172                         return; /* it is in pack - forget about it */
 173                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 174                 errors_found |= ERROR_REACHABLE;
 175                 return;
 176         }
 177 }
 178
 179 /*
 180  * Check a single unreachable object
 181  */
 182 static void check_unreachable_object(struct object *obj)
 183 {
 184         /*
 185          * Missing unreachable object? Ignore it. It's not like
 186          * we miss it (since it can't be reached), nor do we want
 187          * to complain about it being unreachable (since it does
 188          * not exist).
 189          */
 190         if (!obj->parsed)
 191                 return;
 192
 193         /*
 194          * Unreachable object that exists? Show it if asked to,
 195          * since this is something that is prunable.
 196          */
 197         if (show_unreachable) {
 198                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 199                 return;
 200         }
 201
 202         /*
 203          * "!used" means that nothing at all points to it, including
 204          * other unreachable objects. In other words, it's the "tip"
 205          * of some set of unreachable objects, usually a commit that
 206          * got dropped.
 207          *
 208          * Such starting points are more interesting than some random
 209          * set of unreachable objects, so we show them even if the user
 210          * hasn't asked for _all_ unreachable objects. If you have
 211          * deleted a branch by mistake, this is a prime candidate to
 212          * start looking at, for example.
 213          */
 214         if (!obj->used) {
 215                 printf("dangling %s %s\n", typename(obj->type),
 216                        sha1_to_hex(obj->sha1));
 217                 if (write_lost_and_found) {
 218                         char *filename = git_path("lost-found/%s/%s",
 219                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 220                                 sha1_to_hex(obj->sha1));
 221                         FILE *f;
 222
 223                         if (safe_create_leading_directories(filename)) {
 224                                 error("Could not create lost-found");
 225                                 return;
 226                         }
 227                         if (!(f = fopen(filename, "w")))
 228                                 die_errno("Could not open '%s'", filename);
 229                         if (obj->type == OBJ_BLOB) {
 230                                 enum object_type type;
 231                                 unsigned long size;
 232                                 char *buf = read_sha1_file(obj->sha1,
 233                                                 &type, &size);
 234                                 if (buf) {
 235                                         if (fwrite(buf, size, 1, f) != 1)
 236                                                 die_errno("Could not write '%s'",
 237                                                           filename);
 238                                         free(buf);
 239                                 }
 240                         } else
 241                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 242                         if (fclose(f))
 243                                 die_errno("Could not finish '%s'",
 244                                           filename);
 245                 }
 246                 return;
 247         }
 248
 249         /*
 250          * Otherwise? It's there, it's unreachable, and some other unreachable
 251          * object points to it. Ignore it - it's not interesting, and we showed
 252          * all the interesting cases above.
 253          */
 254 }
 255
 256 static void check_object(struct object *obj)
 257 {
 258         if (verbose)
 259                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 260
 261         if (obj->flags & REACHABLE)
 262                 check_reachable_object(obj);
 263         else
 264                 check_unreachable_object(obj);
 265 }
 266
 267 static void check_connectivity(void)
 268 {
 269         int i, max;
 270
 271         /* Traverse the pending reachable objects */
 272         traverse_reachable();
 273
 274         /* Look up all the requirements, warn about missing objects.. */
 275         max = get_max_object_index();
 276         if (verbose)
 277                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 278
 279         for (i = 0; i < max; i++) {
 280                 struct object *obj = get_indexed_object(i);
 281
 282                 if (obj)
 283                         check_object(obj);
 284         }
 285 }
 286
 287 static int fsck_sha1(const unsigned char *sha1)
 288 {
 289         struct object *obj = parse_object(sha1);
 290         if (!obj) {
 291                 errors_found |= ERROR_OBJECT;
 292                 return error("%s: object corrupt or missing",
 293                              sha1_to_hex(sha1));
 294         }
 295         if (obj->flags & SEEN)
 296                 return 0;
 297         obj->flags |= SEEN;
 298
 299         if (verbose)
 300                 fprintf(stderr, "Checking %s %s\n",
 301                         typename(obj->type), sha1_to_hex(obj->sha1));
 302
 303         if (fsck_walk(obj, mark_used, NULL))
 304                 objerror(obj, "broken links");
 305         if (fsck_object(obj, check_strict, fsck_error_func))
 306                 return -1;
 307
 308         if (obj->type == OBJ_TREE) {
 309                 struct tree *item = (struct tree *) obj;
 310
 311                 free(item->buffer);
 312                 item->buffer = NULL;
 313         }
 314
 315         if (obj->type == OBJ_COMMIT) {
 316                 struct commit *commit = (struct commit *) obj;
 317
 318                 free(commit->buffer);
 319                 commit->buffer = NULL;
 320
 321                 if (!commit->parents && show_root)
 322                         printf("root %s\n", sha1_to_hex(commit->object.sha1));
 323         }
 324
 325         if (obj->type == OBJ_TAG) {
 326                 struct tag *tag = (struct tag *) obj;
 327
 328                 if (show_tags && tag->tagged) {
 329                         printf("tagged %s %s", typename(tag->tagged->type), sha1_to_hex(tag->tagged->sha1));
 330                         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 331                 }
 332         }
 333
 334         return 0;
 335 }
 336
 337 /*
 338  * This is the sorting chunk size: make it reasonably
 339  * big so that we can sort well..
 340  */
 341 #define MAX_SHA1_ENTRIES (1024)
 342
 343 struct sha1_entry {
 344         unsigned long ino;
 345         unsigned char sha1[20];
 346 };
 347
 348 static struct {
 349         unsigned long nr;
 350         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 351 } sha1_list;
 352
 353 static int ino_compare(const void *_a, const void *_b)
 354 {
 355         const struct sha1_entry *a = _a, *b = _b;
 356         unsigned long ino1 = a->ino, ino2 = b->ino;
 357         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 358 }
 359
 360 static void fsck_sha1_list(void)
 361 {
 362         int i, nr = sha1_list.nr;
 363
 364         if (SORT_DIRENT)
 365                 qsort(sha1_list.entry, nr,
 366                       sizeof(struct sha1_entry *), ino_compare);
 367         for (i = 0; i < nr; i++) {
 368                 struct sha1_entry *entry = sha1_list.entry[i];
 369                 unsigned char *sha1 = entry->sha1;
 370
 371                 sha1_list.entry[i] = NULL;
 372                 fsck_sha1(sha1);
 373                 free(entry);
 374         }
 375         sha1_list.nr = 0;
 376 }
 377
 378 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 379 {
 380         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 381         int nr;
 382
 383         entry->ino = ino;
 384         hashcpy(entry->sha1, sha1);
 385         nr = sha1_list.nr;
 386         if (nr == MAX_SHA1_ENTRIES) {
 387                 fsck_sha1_list();
 388                 nr = 0;
 389         }
 390         sha1_list.entry[nr] = entry;
 391         sha1_list.nr = ++nr;
 392 }
 393
 394 static inline int is_loose_object_file(struct dirent *de,
 395                                        char *name, unsigned char *sha1)
 396 {
 397         if (strlen(de->d_name) != 38)
 398                 return 0;
 399         memcpy(name + 2, de->d_name, 39);
 400         return !get_sha1_hex(name, sha1);
 401 }
 402
 403 static void fsck_dir(int i, char *path)
 404 {
 405         DIR *dir = opendir(path);
 406         struct dirent *de;
 407         char name[100];
 408
 409         if (!dir)
 410                 return;
 411
 412         if (verbose)
 413                 fprintf(stderr, "Checking directory %s\n", path);
 414
 415         sprintf(name, "%02x", i);
 416         while ((de = readdir(dir)) != NULL) {
 417                 unsigned char sha1[20];
 418
 419                 if (is_dot_or_dotdot(de->d_name))
 420                         continue;
 421                 if (is_loose_object_file(de, name, sha1)) {
 422                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 423                         continue;
 424                 }
 425                 if (!prefixcmp(de->d_name, "tmp_obj_"))
 426                         continue;
 427                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 428         }
 429         closedir(dir);
 430 }
 431
 432 static int default_refs;
 433
 434 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 435                 const char *email, unsigned long timestamp, int tz,
 436                 const char *message, void *cb_data)
 437 {
 438         struct object *obj;
 439
 440         if (verbose)
 441                 fprintf(stderr, "Checking reflog %s->%s\n",
 442                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 443
 444         if (!is_null_sha1(osha1)) {
 445                 obj = lookup_object(osha1);
 446                 if (obj) {
 447                         obj->used = 1;
 448                         mark_object_reachable(obj);
 449                 }
 450         }
 451         obj = lookup_object(nsha1);
 452         if (obj) {
 453                 obj->used = 1;
 454                 mark_object_reachable(obj);
 455         }
 456         return 0;
 457 }
 458
 459 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 460 {
 461         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 462         return 0;
 463 }
 464
 465 static int is_branch(const char *refname)
 466 {
 467         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
 468 }
 469
 470 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 471 {
 472         struct object *obj;
 473
 474         obj = parse_object(sha1);
 475         if (!obj) {
 476                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 477                 /* We'll continue with the rest despite the error.. */
 478                 return 0;
 479         }
 480         if (obj->type != OBJ_COMMIT && is_branch(refname))
 481                 error("%s: not a commit", refname);
 482         default_refs++;
 483         obj->used = 1;
 484         mark_object_reachable(obj);
 485
 486         return 0;
 487 }
 488
 489 static void get_default_heads(void)
 490 {
 491         if (head_points_at && !is_null_sha1(head_sha1))
 492                 fsck_handle_ref("HEAD", head_sha1, 0, NULL);
 493         for_each_ref(fsck_handle_ref, NULL);
 494         if (include_reflogs)
 495                 for_each_reflog(fsck_handle_reflog, NULL);
 496
 497         /*
 498          * Not having any default heads isn't really fatal, but
 499          * it does mean that "--unreachable" no longer makes any
 500          * sense (since in this case everything will obviously
 501          * be unreachable by definition.
 502          *
 503          * Showing dangling objects is valid, though (as those
 504          * dangling objects are likely lost heads).
 505          *
 506          * So we just print a warning about it, and clear the
 507          * "show_unreachable" flag.
 508          */
 509         if (!default_refs) {
 510                 fprintf(stderr, "notice: No default references\n");
 511                 show_unreachable = 0;
 512         }
 513 }
 514
 515 static void fsck_object_dir(const char *path)
 516 {
 517         int i;
 518
 519         if (verbose)
 520                 fprintf(stderr, "Checking object directory\n");
 521
 522         for (i = 0; i < 256; i++) {
 523                 static char dir[4096];
 524                 sprintf(dir, "%s/%02x", path, i);
 525                 fsck_dir(i, dir);
 526         }
 527         fsck_sha1_list();
 528 }
 529
 530 static int fsck_head_link(void)
 531 {
 532         int flag;
 533         int null_is_error = 0;
 534
 535         if (verbose)
 536                 fprintf(stderr, "Checking HEAD link\n");
 537
 538         head_points_at = resolve_ref("HEAD", head_sha1, 0, &flag);
 539         if (!head_points_at)
 540                 return error("Invalid HEAD");
 541         if (!strcmp(head_points_at, "HEAD"))
 542                 /* detached HEAD */
 543                 null_is_error = 1;
 544         else if (prefixcmp(head_points_at, "refs/heads/"))
 545                 return error("HEAD points to something strange (%s)",
 546                              head_points_at);
 547         if (is_null_sha1(head_sha1)) {
 548                 if (null_is_error)
 549                         return error("HEAD: detached HEAD points at nothing");
 550                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 551                         head_points_at + 11);
 552         }
 553         return 0;
 554 }
 555
 556 static int fsck_cache_tree(struct cache_tree *it)
 557 {
 558         int i;
 559         int err = 0;
 560
 561         if (verbose)
 562                 fprintf(stderr, "Checking cache tree\n");
 563
 564         if (0 <= it->entry_count) {
 565                 struct object *obj = parse_object(it->sha1);
 566                 if (!obj) {
 567                         error("%s: invalid sha1 pointer in cache-tree",
 568                               sha1_to_hex(it->sha1));
 569                         return 1;
 570                 }
 571                 obj->used = 1;
 572                 mark_object_reachable(obj);
 573                 if (obj->type != OBJ_TREE)
 574                         err |= objerror(obj, "non-tree in cache-tree");
 575         }
 576         for (i = 0; i < it->subtree_nr; i++)
 577                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 578         return err;
 579 }
 580
 581 static char const * const fsck_usage[] = {
 582         "git fsck [options] [<object>...]",
 583         NULL
 584 };
 585
 586 static struct option fsck_opts[] = {
 587         OPT__VERBOSE(&verbose, "be verbose"),
 588         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 589         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 590         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 591         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 592         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 593         OPT_BOOLEAN(0, "full", &check_full, "also consider packs and alternate objects"),
 594         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 595         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 596                                 "write dangling objects in .git/lost-found"),
 597         OPT_END(),
 598 };
 599
 600 int cmd_fsck(int argc, const char **argv, const char *prefix)
 601 {
 602         int i, heads;
 603         struct alternate_object_database *alt;
 604
 605         errors_found = 0;
 606         read_replace_refs = 0;
 607
 608         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
 609         if (write_lost_and_found) {
 610                 check_full = 1;
 611                 include_reflogs = 0;
 612         }
 613
 614         fsck_head_link();
 615         fsck_object_dir(get_object_directory());
 616
 617         prepare_alt_odb();
 618         for (alt = alt_odb_list; alt; alt = alt->next) {
 619                 char namebuf[PATH_MAX];
 620                 int namelen = alt->name - alt->base;
 621                 memcpy(namebuf, alt->base, namelen);
 622                 namebuf[namelen - 1] = 0;
 623                 fsck_object_dir(namebuf);
 624         }
 625
 626         if (check_full) {
 627                 struct packed_git *p;
 628
 629                 prepare_packed_git();
 630                 for (p = packed_git; p; p = p->next)
 631                         /* verify gives error messages itself */
 632                         verify_pack(p);
 633
 634                 for (p = packed_git; p; p = p->next) {
 635                         uint32_t j, num;
 636                         if (open_pack_index(p))
 637                                 continue;
 638                         num = p->num_objects;
 639                         for (j = 0; j < num; j++)
 640                                 fsck_sha1(nth_packed_object_sha1(p, j));
 641                 }
 642         }
 643
 644         heads = 0;
 645         for (i = 0; i < argc; i++) {
 646                 const char *arg = argv[i];
 647                 unsigned char sha1[20];
 648                 if (!get_sha1(arg, sha1)) {
 649                         struct object *obj = lookup_object(sha1);
 650
 651                         /* Error is printed by lookup_object(). */
 652                         if (!obj)
 653                                 continue;
 654
 655                         obj->used = 1;
 656                         mark_object_reachable(obj);
 657                         heads++;
 658                         continue;
 659                 }
 660                 error("invalid parameter: expected sha1, got '%s'", arg);
 661         }
 662
 663         /*
 664          * If we've not been given any explicit head information, do the
 665          * default ones from .git/refs. We also consider the index file
 666          * in this case (ie this implies --cache).
 667          */
 668         if (!heads) {
 669                 get_default_heads();
 670                 keep_cache_objects = 1;
 671         }
 672
 673         if (keep_cache_objects) {
 674                 read_cache();
 675                 for (i = 0; i < active_nr; i++) {
 676                         unsigned int mode;
 677                         struct blob *blob;
 678                         struct object *obj;
 679
 680                         mode = active_cache[i]->ce_mode;
 681                         if (S_ISGITLINK(mode))
 682                                 continue;
 683                         blob = lookup_blob(active_cache[i]->sha1);
 684                         if (!blob)
 685                                 continue;
 686                         obj = &blob->object;
 687                         obj->used = 1;
 688                         mark_object_reachable(obj);
 689                 }
 690                 if (active_cache_tree)
 691                         fsck_cache_tree(active_cache_tree);
 692         }
 693
 694         check_connectivity();
 695         return errors_found;
 696 }