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 #define ERROR_PACK 04
  33
  34 #ifdef NO_D_INO_IN_DIRENT
  35 #define SORT_DIRENT 0
  36 #define DIRENT_SORT_HINT(de) 0
  37 #else
  38 #define SORT_DIRENT 1
  39 #define DIRENT_SORT_HINT(de) ((de)->d_ino)
  40 #endif
  41
  42 static void objreport(struct object *obj, const char *severity,
  43                       const char *err, va_list params)
  44 {
  45         fprintf(stderr, "%s in %s %s: ",
  46                 severity, typename(obj->type), sha1_to_hex(obj->sha1));
  47         vfprintf(stderr, err, params);
  48         fputs("\n", stderr);
  49 }
  50
  51 __attribute__((format (printf, 2, 3)))
  52 static int objerror(struct object *obj, const char *err, ...)
  53 {
  54         va_list params;
  55         va_start(params, err);
  56         errors_found |= ERROR_OBJECT;
  57         objreport(obj, "error", err, params);
  58         va_end(params);
  59         return -1;
  60 }
  61
  62 __attribute__((format (printf, 3, 4)))
  63 static int fsck_error_func(struct object *obj, int type, const char *err, ...)
  64 {
  65         va_list params;
  66         va_start(params, err);
  67         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", err, params);
  68         va_end(params);
  69         return (type == FSCK_WARN) ? 0 : 1;
  70 }
  71
  72 static struct object_array pending;
  73
  74 static int mark_object(struct object *obj, int type, void *data)
  75 {
  76         struct object *parent = data;
  77
  78         /*
  79          * The only case data is NULL or type is OBJ_ANY is when
  80          * mark_object_reachable() calls us.  All the callers of
  81          * that function has non-NULL obj hence ...
  82          */
  83         if (!obj) {
  84                 /* ... these references to parent->fld are safe here */
  85                 printf("broken link from %7s %s\n",
  86                            typename(parent->type), sha1_to_hex(parent->sha1));
  87                 printf("broken link from %7s %s\n",
  88                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
  89                 errors_found |= ERROR_REACHABLE;
  90                 return 1;
  91         }
  92
  93         if (type != OBJ_ANY && obj->type != type)
  94                 /* ... and the reference to parent is safe here */
  95                 objerror(parent, "wrong object type in link");
  96
  97         if (obj->flags & REACHABLE)
  98                 return 0;
  99         obj->flags |= REACHABLE;
 100         if (!obj->parsed) {
 101                 if (parent && !has_sha1_file(obj->sha1)) {
 102                         printf("broken link from %7s %s\n",
 103                                  typename(parent->type), sha1_to_hex(parent->sha1));
 104                         printf("              to %7s %s\n",
 105                                  typename(obj->type), sha1_to_hex(obj->sha1));
 106                         errors_found |= ERROR_REACHABLE;
 107                 }
 108                 return 1;
 109         }
 110
 111         add_object_array(obj, (void *) parent, &pending);
 112         return 0;
 113 }
 114
 115 static void mark_object_reachable(struct object *obj)
 116 {
 117         mark_object(obj, OBJ_ANY, NULL);
 118 }
 119
 120 static int traverse_one_object(struct object *obj)
 121 {
 122         int result;
 123         struct tree *tree = NULL;
 124
 125         if (obj->type == OBJ_TREE) {
 126                 obj->parsed = 0;
 127                 tree = (struct tree *)obj;
 128                 if (parse_tree(tree) < 0)
 129                         return 1; /* error already displayed */
 130         }
 131         result = fsck_walk(obj, mark_object, obj);
 132         if (tree) {
 133                 free(tree->buffer);
 134                 tree->buffer = NULL;
 135         }
 136         return result;
 137 }
 138
 139 static int traverse_reachable(void)
 140 {
 141         int result = 0;
 142         while (pending.nr) {
 143                 struct object_array_entry *entry;
 144                 struct object *obj;
 145
 146                 entry = pending.objects + --pending.nr;
 147                 obj = entry->item;
 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 && fwrite(buf, 1, size, f) != size)
 236                                         die_errno("Could not write '%s'", filename);
 237                                 free(buf);
 238                         } else
 239                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 240                         if (fclose(f))
 241                                 die_errno("Could not finish '%s'",
 242                                           filename);
 243                 }
 244                 return;
 245         }
 246
 247         /*
 248          * Otherwise? It's there, it's unreachable, and some other unreachable
 249          * object points to it. Ignore it - it's not interesting, and we showed
 250          * all the interesting cases above.
 251          */
 252 }
 253
 254 static void check_object(struct object *obj)
 255 {
 256         if (verbose)
 257                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 258
 259         if (obj->flags & REACHABLE)
 260                 check_reachable_object(obj);
 261         else
 262                 check_unreachable_object(obj);
 263 }
 264
 265 static void check_connectivity(void)
 266 {
 267         int i, max;
 268
 269         /* Traverse the pending reachable objects */
 270         traverse_reachable();
 271
 272         /* Look up all the requirements, warn about missing objects.. */
 273         max = get_max_object_index();
 274         if (verbose)
 275                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 276
 277         for (i = 0; i < max; i++) {
 278                 struct object *obj = get_indexed_object(i);
 279
 280                 if (obj)
 281                         check_object(obj);
 282         }
 283 }
 284
 285 static int fsck_obj(struct object *obj)
 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 static int fsck_sha1(const unsigned char *sha1)
 330 {
 331         struct object *obj = parse_object(sha1);
 332         if (!obj) {
 333                 errors_found |= ERROR_OBJECT;
 334                 return error("%s: object corrupt or missing",
 335                              sha1_to_hex(sha1));
 336         }
 337         return fsck_obj(obj);
 338 }
 339
 340 static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 341                            unsigned long size, void *buffer, int *eaten)
 342 {
 343         struct object *obj;
 344         obj = parse_object_buffer(sha1, type, size, buffer, eaten);
 345         if (!obj) {
 346                 errors_found |= ERROR_OBJECT;
 347                 return error("%s: object corrupt or missing", sha1_to_hex(sha1));
 348         }
 349         return fsck_obj(obj);
 350 }
 351
 352 /*
 353  * This is the sorting chunk size: make it reasonably
 354  * big so that we can sort well..
 355  */
 356 #define MAX_SHA1_ENTRIES (1024)
 357
 358 struct sha1_entry {
 359         unsigned long ino;
 360         unsigned char sha1[20];
 361 };
 362
 363 static struct {
 364         unsigned long nr;
 365         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 366 } sha1_list;
 367
 368 static int ino_compare(const void *_a, const void *_b)
 369 {
 370         const struct sha1_entry *a = _a, *b = _b;
 371         unsigned long ino1 = a->ino, ino2 = b->ino;
 372         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 373 }
 374
 375 static void fsck_sha1_list(void)
 376 {
 377         int i, nr = sha1_list.nr;
 378
 379         if (SORT_DIRENT)
 380                 qsort(sha1_list.entry, nr,
 381                       sizeof(struct sha1_entry *), ino_compare);
 382         for (i = 0; i < nr; i++) {
 383                 struct sha1_entry *entry = sha1_list.entry[i];
 384                 unsigned char *sha1 = entry->sha1;
 385
 386                 sha1_list.entry[i] = NULL;
 387                 fsck_sha1(sha1);
 388                 free(entry);
 389         }
 390         sha1_list.nr = 0;
 391 }
 392
 393 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 394 {
 395         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 396         int nr;
 397
 398         entry->ino = ino;
 399         hashcpy(entry->sha1, sha1);
 400         nr = sha1_list.nr;
 401         if (nr == MAX_SHA1_ENTRIES) {
 402                 fsck_sha1_list();
 403                 nr = 0;
 404         }
 405         sha1_list.entry[nr] = entry;
 406         sha1_list.nr = ++nr;
 407 }
 408
 409 static inline int is_loose_object_file(struct dirent *de,
 410                                        char *name, unsigned char *sha1)
 411 {
 412         if (strlen(de->d_name) != 38)
 413                 return 0;
 414         memcpy(name + 2, de->d_name, 39);
 415         return !get_sha1_hex(name, sha1);
 416 }
 417
 418 static void fsck_dir(int i, char *path)
 419 {
 420         DIR *dir = opendir(path);
 421         struct dirent *de;
 422         char name[100];
 423
 424         if (!dir)
 425                 return;
 426
 427         if (verbose)
 428                 fprintf(stderr, "Checking directory %s\n", path);
 429
 430         sprintf(name, "%02x", i);
 431         while ((de = readdir(dir)) != NULL) {
 432                 unsigned char sha1[20];
 433
 434                 if (is_dot_or_dotdot(de->d_name))
 435                         continue;
 436                 if (is_loose_object_file(de, name, sha1)) {
 437                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 438                         continue;
 439                 }
 440                 if (!prefixcmp(de->d_name, "tmp_obj_"))
 441                         continue;
 442                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 443         }
 444         closedir(dir);
 445 }
 446
 447 static int default_refs;
 448
 449 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 450                 const char *email, unsigned long timestamp, int tz,
 451                 const char *message, void *cb_data)
 452 {
 453         struct object *obj;
 454
 455         if (verbose)
 456                 fprintf(stderr, "Checking reflog %s->%s\n",
 457                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 458
 459         if (!is_null_sha1(osha1)) {
 460                 obj = lookup_object(osha1);
 461                 if (obj) {
 462                         obj->used = 1;
 463                         mark_object_reachable(obj);
 464                 }
 465         }
 466         obj = lookup_object(nsha1);
 467         if (obj) {
 468                 obj->used = 1;
 469                 mark_object_reachable(obj);
 470         }
 471         return 0;
 472 }
 473
 474 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 475 {
 476         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 477         return 0;
 478 }
 479
 480 static int is_branch(const char *refname)
 481 {
 482         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
 483 }
 484
 485 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 486 {
 487         struct object *obj;
 488
 489         obj = parse_object(sha1);
 490         if (!obj) {
 491                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 492                 /* We'll continue with the rest despite the error.. */
 493                 return 0;
 494         }
 495         if (obj->type != OBJ_COMMIT && is_branch(refname))
 496                 error("%s: not a commit", refname);
 497         default_refs++;
 498         obj->used = 1;
 499         mark_object_reachable(obj);
 500
 501         return 0;
 502 }
 503
 504 static void get_default_heads(void)
 505 {
 506         if (head_points_at && !is_null_sha1(head_sha1))
 507                 fsck_handle_ref("HEAD", head_sha1, 0, NULL);
 508         for_each_ref(fsck_handle_ref, NULL);
 509         if (include_reflogs)
 510                 for_each_reflog(fsck_handle_reflog, NULL);
 511
 512         /*
 513          * Not having any default heads isn't really fatal, but
 514          * it does mean that "--unreachable" no longer makes any
 515          * sense (since in this case everything will obviously
 516          * be unreachable by definition.
 517          *
 518          * Showing dangling objects is valid, though (as those
 519          * dangling objects are likely lost heads).
 520          *
 521          * So we just print a warning about it, and clear the
 522          * "show_unreachable" flag.
 523          */
 524         if (!default_refs) {
 525                 fprintf(stderr, "notice: No default references\n");
 526                 show_unreachable = 0;
 527         }
 528 }
 529
 530 static void fsck_object_dir(const char *path)
 531 {
 532         int i;
 533
 534         if (verbose)
 535                 fprintf(stderr, "Checking object directory\n");
 536
 537         for (i = 0; i < 256; i++) {
 538                 static char dir[4096];
 539                 sprintf(dir, "%s/%02x", path, i);
 540                 fsck_dir(i, dir);
 541         }
 542         fsck_sha1_list();
 543 }
 544
 545 static int fsck_head_link(void)
 546 {
 547         int flag;
 548         int null_is_error = 0;
 549
 550         if (verbose)
 551                 fprintf(stderr, "Checking HEAD link\n");
 552
 553         head_points_at = resolve_ref("HEAD", head_sha1, 0, &flag);
 554         if (!head_points_at)
 555                 return error("Invalid HEAD");
 556         if (!strcmp(head_points_at, "HEAD"))
 557                 /* detached HEAD */
 558                 null_is_error = 1;
 559         else if (prefixcmp(head_points_at, "refs/heads/"))
 560                 return error("HEAD points to something strange (%s)",
 561                              head_points_at);
 562         if (is_null_sha1(head_sha1)) {
 563                 if (null_is_error)
 564                         return error("HEAD: detached HEAD points at nothing");
 565                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 566                         head_points_at + 11);
 567         }
 568         return 0;
 569 }
 570
 571 static int fsck_cache_tree(struct cache_tree *it)
 572 {
 573         int i;
 574         int err = 0;
 575
 576         if (verbose)
 577                 fprintf(stderr, "Checking cache tree\n");
 578
 579         if (0 <= it->entry_count) {
 580                 struct object *obj = parse_object(it->sha1);
 581                 if (!obj) {
 582                         error("%s: invalid sha1 pointer in cache-tree",
 583                               sha1_to_hex(it->sha1));
 584                         return 1;
 585                 }
 586                 obj->used = 1;
 587                 mark_object_reachable(obj);
 588                 if (obj->type != OBJ_TREE)
 589                         err |= objerror(obj, "non-tree in cache-tree");
 590         }
 591         for (i = 0; i < it->subtree_nr; i++)
 592                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 593         return err;
 594 }
 595
 596 static char const * const fsck_usage[] = {
 597         "git fsck [options] [<object>...]",
 598         NULL
 599 };
 600
 601 static struct option fsck_opts[] = {
 602         OPT__VERBOSE(&verbose, "be verbose"),
 603         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 604         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 605         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 606         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 607         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 608         OPT_BOOLEAN(0, "full", &check_full, "also consider packs and alternate objects"),
 609         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 610         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 611                                 "write dangling objects in .git/lost-found"),
 612         OPT_END(),
 613 };
 614
 615 int cmd_fsck(int argc, const char **argv, const char *prefix)
 616 {
 617         int i, heads;
 618         struct alternate_object_database *alt;
 619
 620         errors_found = 0;
 621         read_replace_refs = 0;
 622
 623         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
 624         if (write_lost_and_found) {
 625                 check_full = 1;
 626                 include_reflogs = 0;
 627         }
 628
 629         fsck_head_link();
 630         fsck_object_dir(get_object_directory());
 631
 632         prepare_alt_odb();
 633         for (alt = alt_odb_list; alt; alt = alt->next) {
 634                 char namebuf[PATH_MAX];
 635                 int namelen = alt->name - alt->base;
 636                 memcpy(namebuf, alt->base, namelen);
 637                 namebuf[namelen - 1] = 0;
 638                 fsck_object_dir(namebuf);
 639         }
 640
 641         if (check_full) {
 642                 struct packed_git *p;
 643
 644                 prepare_packed_git();
 645                 for (p = packed_git; p; p = p->next)
 646                         /* verify gives error messages itself */
 647                         if (verify_pack(p, fsck_obj_buffer))
 648                                 errors_found |= ERROR_PACK;
 649         }
 650
 651         heads = 0;
 652         for (i = 0; i < argc; i++) {
 653                 const char *arg = argv[i];
 654                 unsigned char sha1[20];
 655                 if (!get_sha1(arg, sha1)) {
 656                         struct object *obj = lookup_object(sha1);
 657
 658                         /* Error is printed by lookup_object(). */
 659                         if (!obj)
 660                                 continue;
 661
 662                         obj->used = 1;
 663                         mark_object_reachable(obj);
 664                         heads++;
 665                         continue;
 666                 }
 667                 error("invalid parameter: expected sha1, got '%s'", arg);
 668         }
 669
 670         /*
 671          * If we've not been given any explicit head information, do the
 672          * default ones from .git/refs. We also consider the index file
 673          * in this case (ie this implies --cache).
 674          */
 675         if (!heads) {
 676                 get_default_heads();
 677                 keep_cache_objects = 1;
 678         }
 679
 680         if (keep_cache_objects) {
 681                 read_cache();
 682                 for (i = 0; i < active_nr; i++) {
 683                         unsigned int mode;
 684                         struct blob *blob;
 685                         struct object *obj;
 686
 687                         mode = active_cache[i]->ce_mode;
 688                         if (S_ISGITLINK(mode))
 689                                 continue;
 690                         blob = lookup_blob(active_cache[i]->sha1);
 691                         if (!blob)
 692                                 continue;
 693                         obj = &blob->object;
 694                         obj->used = 1;
 695                         mark_object_reachable(obj);
 696                 }
 697                 if (active_cache_tree)
 698                         fsck_cache_tree(active_cache_tree);
 699         }
 700
 701         check_connectivity();
 702         return errors_found;
 703 }