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 #include "progress.h"
  15 #include "streaming.h"
  16
  17 #define REACHABLE 0x0001
  18 #define SEEN      0x0002
  19 #define HAS_OBJ   0x0004
  20
  21 static int show_root;
  22 static int show_tags;
  23 static int show_unreachable;
  24 static int include_reflogs = 1;
  25 static int check_full = 1;
  26 static int connectivity_only;
  27 static int check_strict;
  28 static int keep_cache_objects;
  29 static struct fsck_options fsck_walk_options = FSCK_OPTIONS_DEFAULT;
  30 static struct fsck_options fsck_obj_options = FSCK_OPTIONS_DEFAULT;
  31 static struct object_id head_oid;
  32 static const char *head_points_at;
  33 static int errors_found;
  34 static int write_lost_and_found;
  35 static int verbose;
  36 static int show_progress = -1;
  37 static int show_dangling = 1;
  38 #define ERROR_OBJECT 01
  39 #define ERROR_REACHABLE 02
  40 #define ERROR_PACK 04
  41 #define ERROR_REFS 010
  42
  43 static int fsck_config(const char *var, const char *value, void *cb)
  44 {
  45         if (strcmp(var, "fsck.skiplist") == 0) {
  46                 const char *path;
  47                 struct strbuf sb = STRBUF_INIT;
  48
  49                 if (git_config_pathname(&path, var, value))
  50                         return 1;
  51                 strbuf_addf(&sb, "skiplist=%s", path);
  52                 free((char *)path);
  53                 fsck_set_msg_types(&fsck_obj_options, sb.buf);
  54                 strbuf_release(&sb);
  55                 return 0;
  56         }
  57
  58         if (skip_prefix(var, "fsck.", &var)) {
  59                 fsck_set_msg_type(&fsck_obj_options, var, value);
  60                 return 0;
  61         }
  62
  63         return git_default_config(var, value, cb);
  64 }
  65
  66 static void objreport(struct object *obj, const char *msg_type,
  67                         const char *err)
  68 {
  69         fprintf(stderr, "%s in %s %s: %s\n",
  70                 msg_type, typename(obj->type), oid_to_hex(&obj->oid), err);
  71 }
  72
  73 static int objerror(struct object *obj, const char *err)
  74 {
  75         errors_found |= ERROR_OBJECT;
  76         objreport(obj, "error", err);
  77         return -1;
  78 }
  79
  80 static int fsck_error_func(struct object *obj, int type, const char *message)
  81 {
  82         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", message);
  83         return (type == FSCK_WARN) ? 0 : 1;
  84 }
  85
  86 static struct object_array pending;
  87
  88 static int mark_object(struct object *obj, int type, void *data, struct fsck_options *options)
  89 {
  90         struct object *parent = data;
  91
  92         /*
  93          * The only case data is NULL or type is OBJ_ANY is when
  94          * mark_object_reachable() calls us.  All the callers of
  95          * that function has non-NULL obj hence ...
  96          */
  97         if (!obj) {
  98                 /* ... these references to parent->fld are safe here */
  99                 printf("broken link from %7s %s\n",
 100                            typename(parent->type), oid_to_hex(&parent->oid));
 101                 printf("broken link from %7s %s\n",
 102                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
 103                 errors_found |= ERROR_REACHABLE;
 104                 return 1;
 105         }
 106
 107         if (type != OBJ_ANY && obj->type != type)
 108                 /* ... and the reference to parent is safe here */
 109                 objerror(parent, "wrong object type in link");
 110
 111         if (obj->flags & REACHABLE)
 112                 return 0;
 113         obj->flags |= REACHABLE;
 114         if (!(obj->flags & HAS_OBJ)) {
 115                 if (parent && !has_object_file(&obj->oid)) {
 116                         printf("broken link from %7s %s\n",
 117                                  typename(parent->type), oid_to_hex(&parent->oid));
 118                         printf("              to %7s %s\n",
 119                                  typename(obj->type), oid_to_hex(&obj->oid));
 120                         errors_found |= ERROR_REACHABLE;
 121                 }
 122                 return 1;
 123         }
 124
 125         add_object_array(obj, NULL, &pending);
 126         return 0;
 127 }
 128
 129 static void mark_object_reachable(struct object *obj)
 130 {
 131         mark_object(obj, OBJ_ANY, NULL, NULL);
 132 }
 133
 134 static int traverse_one_object(struct object *obj)
 135 {
 136         int result;
 137         struct tree *tree = NULL;
 138
 139         if (obj->type == OBJ_TREE) {
 140                 tree = (struct tree *)obj;
 141                 if (parse_tree(tree) < 0)
 142                         return 1; /* error already displayed */
 143         }
 144         result = fsck_walk(obj, obj, &fsck_walk_options);
 145         if (tree)
 146                 free_tree_buffer(tree);
 147         return result;
 148 }
 149
 150 static int traverse_reachable(void)
 151 {
 152         struct progress *progress = NULL;
 153         unsigned int nr = 0;
 154         int result = 0;
 155         if (show_progress)
 156                 progress = start_progress_delay(_("Checking connectivity"), 0, 0, 2);
 157         while (pending.nr) {
 158                 struct object_array_entry *entry;
 159                 struct object *obj;
 160
 161                 entry = pending.objects + --pending.nr;
 162                 obj = entry->item;
 163                 result |= traverse_one_object(obj);
 164                 display_progress(progress, ++nr);
 165         }
 166         stop_progress(&progress);
 167         return !!result;
 168 }
 169
 170 static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
 171 {
 172         if (!obj)
 173                 return 1;
 174         obj->used = 1;
 175         return 0;
 176 }
 177
 178 /*
 179  * Check a single reachable object
 180  */
 181 static void check_reachable_object(struct object *obj)
 182 {
 183         /*
 184          * We obviously want the object to be parsed,
 185          * except if it was in a pack-file and we didn't
 186          * do a full fsck
 187          */
 188         if (!(obj->flags & HAS_OBJ)) {
 189                 if (has_sha1_pack(obj->oid.hash))
 190                         return; /* it is in pack - forget about it */
 191                 if (connectivity_only && has_object_file(&obj->oid))
 192                         return;
 193                 printf("missing %s %s\n", typename(obj->type), oid_to_hex(&obj->oid));
 194                 errors_found |= ERROR_REACHABLE;
 195                 return;
 196         }
 197 }
 198
 199 /*
 200  * Check a single unreachable object
 201  */
 202 static void check_unreachable_object(struct object *obj)
 203 {
 204         /*
 205          * Missing unreachable object? Ignore it. It's not like
 206          * we miss it (since it can't be reached), nor do we want
 207          * to complain about it being unreachable (since it does
 208          * not exist).
 209          */
 210         if (!obj->parsed)
 211                 return;
 212
 213         /*
 214          * Unreachable object that exists? Show it if asked to,
 215          * since this is something that is prunable.
 216          */
 217         if (show_unreachable) {
 218                 printf("unreachable %s %s\n", typename(obj->type), oid_to_hex(&obj->oid));
 219                 return;
 220         }
 221
 222         /*
 223          * "!used" means that nothing at all points to it, including
 224          * other unreachable objects. In other words, it's the "tip"
 225          * of some set of unreachable objects, usually a commit that
 226          * got dropped.
 227          *
 228          * Such starting points are more interesting than some random
 229          * set of unreachable objects, so we show them even if the user
 230          * hasn't asked for _all_ unreachable objects. If you have
 231          * deleted a branch by mistake, this is a prime candidate to
 232          * start looking at, for example.
 233          */
 234         if (!obj->used) {
 235                 if (show_dangling)
 236                         printf("dangling %s %s\n", typename(obj->type),
 237                                oid_to_hex(&obj->oid));
 238                 if (write_lost_and_found) {
 239                         char *filename = git_pathdup("lost-found/%s/%s",
 240                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 241                                 oid_to_hex(&obj->oid));
 242                         FILE *f;
 243
 244                         if (safe_create_leading_directories_const(filename)) {
 245                                 error("Could not create lost-found");
 246                                 free(filename);
 247                                 return;
 248                         }
 249                         if (!(f = fopen(filename, "w")))
 250                                 die_errno("Could not open '%s'", filename);
 251                         if (obj->type == OBJ_BLOB) {
 252                                 if (stream_blob_to_fd(fileno(f), obj->oid.hash, NULL, 1))
 253                                         die_errno("Could not write '%s'", filename);
 254                         } else
 255                                 fprintf(f, "%s\n", oid_to_hex(&obj->oid));
 256                         if (fclose(f))
 257                                 die_errno("Could not finish '%s'",
 258                                           filename);
 259                         free(filename);
 260                 }
 261                 return;
 262         }
 263
 264         /*
 265          * Otherwise? It's there, it's unreachable, and some other unreachable
 266          * object points to it. Ignore it - it's not interesting, and we showed
 267          * all the interesting cases above.
 268          */
 269 }
 270
 271 static void check_object(struct object *obj)
 272 {
 273         if (verbose)
 274                 fprintf(stderr, "Checking %s\n", oid_to_hex(&obj->oid));
 275
 276         if (obj->flags & REACHABLE)
 277                 check_reachable_object(obj);
 278         else
 279                 check_unreachable_object(obj);
 280 }
 281
 282 static void check_connectivity(void)
 283 {
 284         int i, max;
 285
 286         /* Traverse the pending reachable objects */
 287         traverse_reachable();
 288
 289         /* Look up all the requirements, warn about missing objects.. */
 290         max = get_max_object_index();
 291         if (verbose)
 292                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 293
 294         for (i = 0; i < max; i++) {
 295                 struct object *obj = get_indexed_object(i);
 296
 297                 if (obj)
 298                         check_object(obj);
 299         }
 300 }
 301
 302 static int fsck_obj(struct object *obj)
 303 {
 304         if (obj->flags & SEEN)
 305                 return 0;
 306         obj->flags |= SEEN;
 307
 308         if (verbose)
 309                 fprintf(stderr, "Checking %s %s\n",
 310                         typename(obj->type), oid_to_hex(&obj->oid));
 311
 312         if (fsck_walk(obj, NULL, &fsck_obj_options))
 313                 objerror(obj, "broken links");
 314         if (fsck_object(obj, NULL, 0, &fsck_obj_options))
 315                 return -1;
 316
 317         if (obj->type == OBJ_TREE) {
 318                 struct tree *item = (struct tree *) obj;
 319
 320                 free_tree_buffer(item);
 321         }
 322
 323         if (obj->type == OBJ_COMMIT) {
 324                 struct commit *commit = (struct commit *) obj;
 325
 326                 free_commit_buffer(commit);
 327
 328                 if (!commit->parents && show_root)
 329                         printf("root %s\n", oid_to_hex(&commit->object.oid));
 330         }
 331
 332         if (obj->type == OBJ_TAG) {
 333                 struct tag *tag = (struct tag *) obj;
 334
 335                 if (show_tags && tag->tagged) {
 336                         printf("tagged %s %s", typename(tag->tagged->type), oid_to_hex(&tag->tagged->oid));
 337                         printf(" (%s) in %s\n", tag->tag, oid_to_hex(&tag->object.oid));
 338                 }
 339         }
 340
 341         return 0;
 342 }
 343
 344 static int fsck_sha1(const unsigned char *sha1)
 345 {
 346         struct object *obj = parse_object(sha1);
 347         if (!obj) {
 348                 errors_found |= ERROR_OBJECT;
 349                 return error("%s: object corrupt or missing",
 350                              sha1_to_hex(sha1));
 351         }
 352         obj->flags |= HAS_OBJ;
 353         return fsck_obj(obj);
 354 }
 355
 356 static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
 357                            unsigned long size, void *buffer, int *eaten)
 358 {
 359         /*
 360          * Note, buffer may be NULL if type is OBJ_BLOB. See
 361          * verify_packfile(), data_valid variable for details.
 362          */
 363         struct object *obj;
 364         obj = parse_object_buffer(sha1, type, size, buffer, eaten);
 365         if (!obj) {
 366                 errors_found |= ERROR_OBJECT;
 367                 return error("%s: object corrupt or missing", sha1_to_hex(sha1));
 368         }
 369         obj->flags = HAS_OBJ;
 370         return fsck_obj(obj);
 371 }
 372
 373 static int default_refs;
 374
 375 static void fsck_handle_reflog_sha1(const char *refname, unsigned char *sha1)
 376 {
 377         struct object *obj;
 378
 379         if (!is_null_sha1(sha1)) {
 380                 obj = lookup_object(sha1);
 381                 if (obj) {
 382                         obj->used = 1;
 383                         mark_object_reachable(obj);
 384                 } else {
 385                         error("%s: invalid reflog entry %s", refname, sha1_to_hex(sha1));
 386                         errors_found |= ERROR_REACHABLE;
 387                 }
 388         }
 389 }
 390
 391 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 392                 const char *email, unsigned long timestamp, int tz,
 393                 const char *message, void *cb_data)
 394 {
 395         const char *refname = cb_data;
 396
 397         if (verbose)
 398                 fprintf(stderr, "Checking reflog %s->%s\n",
 399                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 400
 401         fsck_handle_reflog_sha1(refname, osha1);
 402         fsck_handle_reflog_sha1(refname, nsha1);
 403         return 0;
 404 }
 405
 406 static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
 407                               int flag, void *cb_data)
 408 {
 409         for_each_reflog_ent(logname, fsck_handle_reflog_ent, (void *)logname);
 410         return 0;
 411 }
 412
 413 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
 414                            int flag, void *cb_data)
 415 {
 416         struct object *obj;
 417
 418         obj = parse_object(oid->hash);
 419         if (!obj) {
 420                 error("%s: invalid sha1 pointer %s", refname, oid_to_hex(oid));
 421                 errors_found |= ERROR_REACHABLE;
 422                 /* We'll continue with the rest despite the error.. */
 423                 return 0;
 424         }
 425         if (obj->type != OBJ_COMMIT && is_branch(refname)) {
 426                 error("%s: not a commit", refname);
 427                 errors_found |= ERROR_REFS;
 428         }
 429         default_refs++;
 430         obj->used = 1;
 431         mark_object_reachable(obj);
 432
 433         return 0;
 434 }
 435
 436 static void get_default_heads(void)
 437 {
 438         if (head_points_at && !is_null_oid(&head_oid))
 439                 fsck_handle_ref("HEAD", &head_oid, 0, NULL);
 440         for_each_rawref(fsck_handle_ref, NULL);
 441         if (include_reflogs)
 442                 for_each_reflog(fsck_handle_reflog, NULL);
 443
 444         /*
 445          * Not having any default heads isn't really fatal, but
 446          * it does mean that "--unreachable" no longer makes any
 447          * sense (since in this case everything will obviously
 448          * be unreachable by definition.
 449          *
 450          * Showing dangling objects is valid, though (as those
 451          * dangling objects are likely lost heads).
 452          *
 453          * So we just print a warning about it, and clear the
 454          * "show_unreachable" flag.
 455          */
 456         if (!default_refs) {
 457                 fprintf(stderr, "notice: No default references\n");
 458                 show_unreachable = 0;
 459         }
 460 }
 461
 462 static int fsck_loose(const unsigned char *sha1, const char *path, void *data)
 463 {
 464         if (fsck_sha1(sha1))
 465                 errors_found |= ERROR_OBJECT;
 466         return 0;
 467 }
 468
 469 static int fsck_cruft(const char *basename, const char *path, void *data)
 470 {
 471         if (!starts_with(basename, "tmp_obj_"))
 472                 fprintf(stderr, "bad sha1 file: %s\n", path);
 473         return 0;
 474 }
 475
 476 static int fsck_subdir(int nr, const char *path, void *progress)
 477 {
 478         display_progress(progress, nr + 1);
 479         return 0;
 480 }
 481
 482 static void fsck_object_dir(const char *path)
 483 {
 484         struct progress *progress = NULL;
 485
 486         if (verbose)
 487                 fprintf(stderr, "Checking object directory\n");
 488
 489         if (show_progress)
 490                 progress = start_progress(_("Checking object directories"), 256);
 491
 492         for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
 493                                       progress);
 494         display_progress(progress, 256);
 495         stop_progress(&progress);
 496 }
 497
 498 static int fsck_head_link(void)
 499 {
 500         int null_is_error = 0;
 501
 502         if (verbose)
 503                 fprintf(stderr, "Checking HEAD link\n");
 504
 505         head_points_at = resolve_ref_unsafe("HEAD", 0, head_oid.hash, NULL);
 506         if (!head_points_at) {
 507                 errors_found |= ERROR_REFS;
 508                 return error("Invalid HEAD");
 509         }
 510         if (!strcmp(head_points_at, "HEAD"))
 511                 /* detached HEAD */
 512                 null_is_error = 1;
 513         else if (!starts_with(head_points_at, "refs/heads/")) {
 514                 errors_found |= ERROR_REFS;
 515                 return error("HEAD points to something strange (%s)",
 516                              head_points_at);
 517         }
 518         if (is_null_oid(&head_oid)) {
 519                 if (null_is_error) {
 520                         errors_found |= ERROR_REFS;
 521                         return error("HEAD: detached HEAD points at nothing");
 522                 }
 523                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 524                         head_points_at + 11);
 525         }
 526         return 0;
 527 }
 528
 529 static int fsck_cache_tree(struct cache_tree *it)
 530 {
 531         int i;
 532         int err = 0;
 533
 534         if (verbose)
 535                 fprintf(stderr, "Checking cache tree\n");
 536
 537         if (0 <= it->entry_count) {
 538                 struct object *obj = parse_object(it->sha1);
 539                 if (!obj) {
 540                         error("%s: invalid sha1 pointer in cache-tree",
 541                               sha1_to_hex(it->sha1));
 542                         errors_found |= ERROR_REFS;
 543                         return 1;
 544                 }
 545                 obj->used = 1;
 546                 mark_object_reachable(obj);
 547                 if (obj->type != OBJ_TREE)
 548                         err |= objerror(obj, "non-tree in cache-tree");
 549         }
 550         for (i = 0; i < it->subtree_nr; i++)
 551                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 552         return err;
 553 }
 554
 555 static char const * const fsck_usage[] = {
 556         N_("git fsck [<options>] [<object>...]"),
 557         NULL
 558 };
 559
 560 static struct option fsck_opts[] = {
 561         OPT__VERBOSE(&verbose, N_("be verbose")),
 562         OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
 563         OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
 564         OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
 565         OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
 566         OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
 567         OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
 568         OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
 569         OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
 570         OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
 571         OPT_BOOL(0, "lost-found", &write_lost_and_found,
 572                                 N_("write dangling objects in .git/lost-found")),
 573         OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
 574         OPT_END(),
 575 };
 576
 577 int cmd_fsck(int argc, const char **argv, const char *prefix)
 578 {
 579         int i, heads;
 580         struct alternate_object_database *alt;
 581
 582         errors_found = 0;
 583         check_replace_refs = 0;
 584
 585         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
 586
 587         fsck_walk_options.walk = mark_object;
 588         fsck_obj_options.walk = mark_used;
 589         fsck_obj_options.error_func = fsck_error_func;
 590         if (check_strict)
 591                 fsck_obj_options.strict = 1;
 592
 593         if (show_progress == -1)
 594                 show_progress = isatty(2);
 595         if (verbose)
 596                 show_progress = 0;
 597
 598         if (write_lost_and_found) {
 599                 check_full = 1;
 600                 include_reflogs = 0;
 601         }
 602
 603         git_config(fsck_config, NULL);
 604
 605         fsck_head_link();
 606         if (!connectivity_only) {
 607                 fsck_object_dir(get_object_directory());
 608
 609                 prepare_alt_odb();
 610                 for (alt = alt_odb_list; alt; alt = alt->next) {
 611                         /* directory name, minus trailing slash */
 612                         size_t namelen = alt->name - alt->base - 1;
 613                         struct strbuf name = STRBUF_INIT;
 614                         strbuf_add(&name, alt->base, namelen);
 615                         fsck_object_dir(name.buf);
 616                         strbuf_release(&name);
 617                 }
 618         }
 619
 620         if (check_full) {
 621                 struct packed_git *p;
 622                 uint32_t total = 0, count = 0;
 623                 struct progress *progress = NULL;
 624
 625                 prepare_packed_git();
 626
 627                 if (show_progress) {
 628                         for (p = packed_git; p; p = p->next) {
 629                                 if (open_pack_index(p))
 630                                         continue;
 631                                 total += p->num_objects;
 632                         }
 633
 634                         progress = start_progress(_("Checking objects"), total);
 635                 }
 636                 for (p = packed_git; p; p = p->next) {
 637                         /* verify gives error messages itself */
 638                         if (verify_pack(p, fsck_obj_buffer,
 639                                         progress, count))
 640                                 errors_found |= ERROR_PACK;
 641                         count += p->num_objects;
 642                 }
 643                 stop_progress(&progress);
 644         }
 645
 646         heads = 0;
 647         for (i = 0; i < argc; i++) {
 648                 const char *arg = argv[i];
 649                 unsigned char sha1[20];
 650                 if (!get_sha1(arg, sha1)) {
 651                         struct object *obj = lookup_object(sha1);
 652
 653                         /* Error is printed by lookup_object(). */
 654                         if (!obj)
 655                                 continue;
 656
 657                         obj->used = 1;
 658                         mark_object_reachable(obj);
 659                         heads++;
 660                         continue;
 661                 }
 662                 error("invalid parameter: expected sha1, got '%s'", arg);
 663         }
 664
 665         /*
 666          * If we've not been given any explicit head information, do the
 667          * default ones from .git/refs. We also consider the index file
 668          * in this case (ie this implies --cache).
 669          */
 670         if (!heads) {
 671                 get_default_heads();
 672                 keep_cache_objects = 1;
 673         }
 674
 675         if (keep_cache_objects) {
 676                 read_cache();
 677                 for (i = 0; i < active_nr; i++) {
 678                         unsigned int mode;
 679                         struct blob *blob;
 680                         struct object *obj;
 681
 682                         mode = active_cache[i]->ce_mode;
 683                         if (S_ISGITLINK(mode))
 684                                 continue;
 685                         blob = lookup_blob(active_cache[i]->sha1);
 686                         if (!blob)
 687                                 continue;
 688                         obj = &blob->object;
 689                         obj->used = 1;
 690                         mark_object_reachable(obj);
 691                 }
 692                 if (active_cache_tree)
 693                         fsck_cache_tree(active_cache_tree);
 694         }
 695
 696         check_connectivity();
 697         return errors_found;
 698 }