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
  14 #define REACHABLE 0x0001
  15 #define SEEN      0x0002
  16
  17 static int show_root;
  18 static int show_tags;
  19 static int show_unreachable;
  20 static int include_reflogs = 1;
  21 static int check_full;
  22 static int check_strict;
  23 static int keep_cache_objects;
  24 static unsigned char head_sha1[20];
  25 static int errors_found;
  26 static int write_lost_and_found;
  27 static int verbose;
  28 #define ERROR_OBJECT 01
  29 #define ERROR_REACHABLE 02
  30
  31 #ifdef NO_D_INO_IN_DIRENT
  32 #define SORT_DIRENT 0
  33 #define DIRENT_SORT_HINT(de) 0
  34 #else
  35 #define SORT_DIRENT 1
  36 #define DIRENT_SORT_HINT(de) ((de)->d_ino)
  37 #endif
  38
  39 static void objreport(struct object *obj, const char *severity,
  40                       const char *err, va_list params)
  41 {
  42         fprintf(stderr, "%s in %s %s: ",
  43                 severity, typename(obj->type), sha1_to_hex(obj->sha1));
  44         vfprintf(stderr, err, params);
  45         fputs("\n", stderr);
  46 }
  47
  48 static int objerror(struct object *obj, const char *err, ...)
  49 {
  50         va_list params;
  51         va_start(params, err);
  52         errors_found |= ERROR_OBJECT;
  53         objreport(obj, "error", err, params);
  54         va_end(params);
  55         return -1;
  56 }
  57
  58 static int fsck_error_func(struct object *obj, int type, const char *err, ...)
  59 {
  60         va_list params;
  61         va_start(params, err);
  62         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", err, params);
  63         va_end(params);
  64         return (type == FSCK_WARN) ? 0 : 1;
  65 }
  66
  67 static int mark_object(struct object *obj, int type, void *data)
  68 {
  69         struct tree *tree = NULL;
  70         struct object *parent = data;
  71         int result;
  72
  73         if (!obj) {
  74                 printf("broken link from %7s %s\n",
  75                            typename(parent->type), sha1_to_hex(parent->sha1));
  76                 printf("broken link from %7s %s\n",
  77                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
  78                 errors_found |= ERROR_REACHABLE;
  79                 return 1;
  80         }
  81
  82         if (type != OBJ_ANY && obj->type != type)
  83                 objerror(parent, "wrong object type in link");
  84
  85         if (obj->flags & REACHABLE)
  86                 return 0;
  87         obj->flags |= REACHABLE;
  88         if (!obj->parsed) {
  89                 if (parent && !has_sha1_file(obj->sha1)) {
  90                         printf("broken link from %7s %s\n",
  91                                  typename(parent->type), sha1_to_hex(parent->sha1));
  92                         printf("              to %7s %s\n",
  93                                  typename(obj->type), sha1_to_hex(obj->sha1));
  94                         errors_found |= ERROR_REACHABLE;
  95                 }
  96                 return 1;
  97         }
  98
  99         if (obj->type == OBJ_TREE) {
 100                 obj->parsed = 0;
 101                 tree = (struct tree *)obj;
 102                 if (parse_tree(tree) < 0)
 103                         return 1; /* error already displayed */
 104         }
 105         result = fsck_walk(obj, mark_object, obj);
 106         if (tree) {
 107                 free(tree->buffer);
 108                 tree->buffer = NULL;
 109         }
 110         if (result < 0)
 111                 result = 1;
 112
 113         return result;
 114 }
 115
 116 static void mark_object_reachable(struct object *obj)
 117 {
 118         mark_object(obj, OBJ_ANY, 0);
 119 }
 120
 121 static int mark_used(struct object *obj, int type, void *data)
 122 {
 123         if (!obj)
 124                 return 1;
 125         obj->used = 1;
 126         return 0;
 127 }
 128
 129 /*
 130  * Check a single reachable object
 131  */
 132 static void check_reachable_object(struct object *obj)
 133 {
 134         /*
 135          * We obviously want the object to be parsed,
 136          * except if it was in a pack-file and we didn't
 137          * do a full fsck
 138          */
 139         if (!obj->parsed) {
 140                 if (has_sha1_pack(obj->sha1, NULL))
 141                         return; /* it is in pack - forget about it */
 142                 printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 143                 errors_found |= ERROR_REACHABLE;
 144                 return;
 145         }
 146 }
 147
 148 /*
 149  * Check a single unreachable object
 150  */
 151 static void check_unreachable_object(struct object *obj)
 152 {
 153         /*
 154          * Missing unreachable object? Ignore it. It's not like
 155          * we miss it (since it can't be reached), nor do we want
 156          * to complain about it being unreachable (since it does
 157          * not exist).
 158          */
 159         if (!obj->parsed)
 160                 return;
 161
 162         /*
 163          * Unreachable object that exists? Show it if asked to,
 164          * since this is something that is prunable.
 165          */
 166         if (show_unreachable) {
 167                 printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
 168                 return;
 169         }
 170
 171         /*
 172          * "!used" means that nothing at all points to it, including
 173          * other unreachable objects. In other words, it's the "tip"
 174          * of some set of unreachable objects, usually a commit that
 175          * got dropped.
 176          *
 177          * Such starting points are more interesting than some random
 178          * set of unreachable objects, so we show them even if the user
 179          * hasn't asked for _all_ unreachable objects. If you have
 180          * deleted a branch by mistake, this is a prime candidate to
 181          * start looking at, for example.
 182          */
 183         if (!obj->used) {
 184                 printf("dangling %s %s\n", typename(obj->type),
 185                        sha1_to_hex(obj->sha1));
 186                 if (write_lost_and_found) {
 187                         char *filename = git_path("lost-found/%s/%s",
 188                                 obj->type == OBJ_COMMIT ? "commit" : "other",
 189                                 sha1_to_hex(obj->sha1));
 190                         FILE *f;
 191
 192                         if (safe_create_leading_directories(filename)) {
 193                                 error("Could not create lost-found");
 194                                 return;
 195                         }
 196                         if (!(f = fopen(filename, "w")))
 197                                 die("Could not open %s", filename);
 198                         if (obj->type == OBJ_BLOB) {
 199                                 enum object_type type;
 200                                 unsigned long size;
 201                                 char *buf = read_sha1_file(obj->sha1,
 202                                                 &type, &size);
 203                                 if (buf) {
 204                                         fwrite(buf, size, 1, f);
 205                                         free(buf);
 206                                 }
 207                         } else
 208                                 fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 209                         fclose(f);
 210                 }
 211                 return;
 212         }
 213
 214         /*
 215          * Otherwise? It's there, it's unreachable, and some other unreachable
 216          * object points to it. Ignore it - it's not interesting, and we showed
 217          * all the interesting cases above.
 218          */
 219 }
 220
 221 static void check_object(struct object *obj)
 222 {
 223         if (verbose)
 224                 fprintf(stderr, "Checking %s\n", sha1_to_hex(obj->sha1));
 225
 226         if (obj->flags & REACHABLE)
 227                 check_reachable_object(obj);
 228         else
 229                 check_unreachable_object(obj);
 230 }
 231
 232 static void check_connectivity(void)
 233 {
 234         int i, max;
 235
 236         /* Look up all the requirements, warn about missing objects.. */
 237         max = get_max_object_index();
 238         if (verbose)
 239                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
 240
 241         for (i = 0; i < max; i++) {
 242                 struct object *obj = get_indexed_object(i);
 243
 244                 if (obj)
 245                         check_object(obj);
 246         }
 247 }
 248
 249 static int fsck_sha1(const unsigned char *sha1)
 250 {
 251         struct object *obj = parse_object(sha1);
 252         if (!obj) {
 253                 errors_found |= ERROR_OBJECT;
 254                 return error("%s: object corrupt or missing",
 255                              sha1_to_hex(sha1));
 256         }
 257         if (obj->flags & SEEN)
 258                 return 0;
 259         obj->flags |= SEEN;
 260
 261         if (verbose)
 262                 fprintf(stderr, "Checking %s %s\n",
 263                         typename(obj->type), sha1_to_hex(obj->sha1));
 264
 265         if (fsck_walk(obj, mark_used, 0))
 266                 objerror(obj, "broken links");
 267         if (fsck_object(obj, check_strict, fsck_error_func))
 268                 return -1;
 269
 270         if (obj->type == OBJ_TREE) {
 271                 struct tree *item = (struct tree *) obj;
 272
 273                 free(item->buffer);
 274                 item->buffer = NULL;
 275         }
 276
 277         if (obj->type == OBJ_COMMIT) {
 278                 struct commit *commit = (struct commit *) obj;
 279
 280                 free(commit->buffer);
 281                 commit->buffer = NULL;
 282
 283                 if (!commit->parents && show_root)
 284                         printf("root %s\n", sha1_to_hex(commit->object.sha1));
 285         }
 286
 287         if (obj->type == OBJ_TAG) {
 288                 struct tag *tag = (struct tag *) obj;
 289
 290                 if (show_tags && tag->tagged) {
 291                         printf("tagged %s %s", typename(tag->tagged->type), sha1_to_hex(tag->tagged->sha1));
 292                         printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
 293                 }
 294         }
 295
 296         return 0;
 297 }
 298
 299 /*
 300  * This is the sorting chunk size: make it reasonably
 301  * big so that we can sort well..
 302  */
 303 #define MAX_SHA1_ENTRIES (1024)
 304
 305 struct sha1_entry {
 306         unsigned long ino;
 307         unsigned char sha1[20];
 308 };
 309
 310 static struct {
 311         unsigned long nr;
 312         struct sha1_entry *entry[MAX_SHA1_ENTRIES];
 313 } sha1_list;
 314
 315 static int ino_compare(const void *_a, const void *_b)
 316 {
 317         const struct sha1_entry *a = _a, *b = _b;
 318         unsigned long ino1 = a->ino, ino2 = b->ino;
 319         return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
 320 }
 321
 322 static void fsck_sha1_list(void)
 323 {
 324         int i, nr = sha1_list.nr;
 325
 326         if (SORT_DIRENT)
 327                 qsort(sha1_list.entry, nr,
 328                       sizeof(struct sha1_entry *), ino_compare);
 329         for (i = 0; i < nr; i++) {
 330                 struct sha1_entry *entry = sha1_list.entry[i];
 331                 unsigned char *sha1 = entry->sha1;
 332
 333                 sha1_list.entry[i] = NULL;
 334                 fsck_sha1(sha1);
 335                 free(entry);
 336         }
 337         sha1_list.nr = 0;
 338 }
 339
 340 static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 341 {
 342         struct sha1_entry *entry = xmalloc(sizeof(*entry));
 343         int nr;
 344
 345         entry->ino = ino;
 346         hashcpy(entry->sha1, sha1);
 347         nr = sha1_list.nr;
 348         if (nr == MAX_SHA1_ENTRIES) {
 349                 fsck_sha1_list();
 350                 nr = 0;
 351         }
 352         sha1_list.entry[nr] = entry;
 353         sha1_list.nr = ++nr;
 354 }
 355
 356 static void fsck_dir(int i, char *path)
 357 {
 358         DIR *dir = opendir(path);
 359         struct dirent *de;
 360
 361         if (!dir)
 362                 return;
 363
 364         if (verbose)
 365                 fprintf(stderr, "Checking directory %s\n", path);
 366
 367         while ((de = readdir(dir)) != NULL) {
 368                 char name[100];
 369                 unsigned char sha1[20];
 370                 int len = strlen(de->d_name);
 371
 372                 switch (len) {
 373                 case 2:
 374                         if (de->d_name[1] != '.')
 375                                 break;
 376                 case 1:
 377                         if (de->d_name[0] != '.')
 378                                 break;
 379                         continue;
 380                 case 38:
 381                         sprintf(name, "%02x", i);
 382                         memcpy(name+2, de->d_name, len+1);
 383                         if (get_sha1_hex(name, sha1) < 0)
 384                                 break;
 385                         add_sha1_list(sha1, DIRENT_SORT_HINT(de));
 386                         continue;
 387                 }
 388                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 389         }
 390         closedir(dir);
 391 }
 392
 393 static int default_refs;
 394
 395 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 396                 const char *email, unsigned long timestamp, int tz,
 397                 const char *message, void *cb_data)
 398 {
 399         struct object *obj;
 400
 401         if (verbose)
 402                 fprintf(stderr, "Checking reflog %s->%s\n",
 403                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 404
 405         if (!is_null_sha1(osha1)) {
 406                 obj = lookup_object(osha1);
 407                 if (obj) {
 408                         obj->used = 1;
 409                         mark_object_reachable(obj);
 410                 }
 411         }
 412         obj = lookup_object(nsha1);
 413         if (obj) {
 414                 obj->used = 1;
 415                 mark_object_reachable(obj);
 416         }
 417         return 0;
 418 }
 419
 420 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 421 {
 422         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 423         return 0;
 424 }
 425
 426 static int is_branch(const char *refname)
 427 {
 428         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
 429 }
 430
 431 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 432 {
 433         struct object *obj;
 434
 435         obj = parse_object(sha1);
 436         if (!obj) {
 437                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 438                 /* We'll continue with the rest despite the error.. */
 439                 return 0;
 440         }
 441         if (obj->type != OBJ_COMMIT && is_branch(refname))
 442                 error("%s: not a commit", refname);
 443         default_refs++;
 444         obj->used = 1;
 445         mark_object_reachable(obj);
 446
 447         return 0;
 448 }
 449
 450 static void get_default_heads(void)
 451 {
 452         for_each_ref(fsck_handle_ref, NULL);
 453         if (include_reflogs)
 454                 for_each_reflog(fsck_handle_reflog, NULL);
 455
 456         /*
 457          * Not having any default heads isn't really fatal, but
 458          * it does mean that "--unreachable" no longer makes any
 459          * sense (since in this case everything will obviously
 460          * be unreachable by definition.
 461          *
 462          * Showing dangling objects is valid, though (as those
 463          * dangling objects are likely lost heads).
 464          *
 465          * So we just print a warning about it, and clear the
 466          * "show_unreachable" flag.
 467          */
 468         if (!default_refs) {
 469                 fprintf(stderr, "notice: No default references\n");
 470                 show_unreachable = 0;
 471         }
 472 }
 473
 474 static void fsck_object_dir(const char *path)
 475 {
 476         int i;
 477
 478         if (verbose)
 479                 fprintf(stderr, "Checking object directory\n");
 480
 481         for (i = 0; i < 256; i++) {
 482                 static char dir[4096];
 483                 sprintf(dir, "%s/%02x", path, i);
 484                 fsck_dir(i, dir);
 485         }
 486         fsck_sha1_list();
 487 }
 488
 489 static int fsck_head_link(void)
 490 {
 491         unsigned char sha1[20];
 492         int flag;
 493         int null_is_error = 0;
 494         const char *head_points_at = resolve_ref("HEAD", sha1, 0, &flag);
 495
 496         if (verbose)
 497                 fprintf(stderr, "Checking HEAD link\n");
 498
 499         if (!head_points_at)
 500                 return error("Invalid HEAD");
 501         if (!strcmp(head_points_at, "HEAD"))
 502                 /* detached HEAD */
 503                 null_is_error = 1;
 504         else if (prefixcmp(head_points_at, "refs/heads/"))
 505                 return error("HEAD points to something strange (%s)",
 506                              head_points_at);
 507         if (is_null_sha1(sha1)) {
 508                 if (null_is_error)
 509                         return error("HEAD: detached HEAD points at nothing");
 510                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 511                         head_points_at + 11);
 512         }
 513         return 0;
 514 }
 515
 516 static int fsck_cache_tree(struct cache_tree *it)
 517 {
 518         int i;
 519         int err = 0;
 520
 521         if (verbose)
 522                 fprintf(stderr, "Checking cache tree\n");
 523
 524         if (0 <= it->entry_count) {
 525                 struct object *obj = parse_object(it->sha1);
 526                 if (!obj) {
 527                         error("%s: invalid sha1 pointer in cache-tree",
 528                               sha1_to_hex(it->sha1));
 529                         return 1;
 530                 }
 531                 mark_object_reachable(obj);
 532                 obj->used = 1;
 533                 if (obj->type != OBJ_TREE)
 534                         err |= objerror(obj, "non-tree in cache-tree");
 535         }
 536         for (i = 0; i < it->subtree_nr; i++)
 537                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 538         return err;
 539 }
 540
 541 static char const * const fsck_usage[] = {
 542         "git-fsck [options] [<object>...]",
 543         NULL
 544 };
 545
 546 static struct option fsck_opts[] = {
 547         OPT__VERBOSE(&verbose),
 548         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 549         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 550         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 551         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 552         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 553         OPT_BOOLEAN(0, "full", &check_full, "also consider alternate objects"),
 554         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 555         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 556                                 "write dangling objects in .git/lost-found"),
 557         OPT_END(),
 558 };
 559
 560 int cmd_fsck(int argc, const char **argv, const char *prefix)
 561 {
 562         int i, heads;
 563
 564         errors_found = 0;
 565
 566         argc = parse_options(argc, argv, fsck_opts, fsck_usage, 0);
 567         if (write_lost_and_found) {
 568                 check_full = 1;
 569                 include_reflogs = 0;
 570         }
 571
 572         fsck_head_link();
 573         fsck_object_dir(get_object_directory());
 574         if (check_full) {
 575                 struct alternate_object_database *alt;
 576                 struct packed_git *p;
 577                 prepare_alt_odb();
 578                 for (alt = alt_odb_list; alt; alt = alt->next) {
 579                         char namebuf[PATH_MAX];
 580                         int namelen = alt->name - alt->base;
 581                         memcpy(namebuf, alt->base, namelen);
 582                         namebuf[namelen - 1] = 0;
 583                         fsck_object_dir(namebuf);
 584                 }
 585                 prepare_packed_git();
 586                 for (p = packed_git; p; p = p->next)
 587                         /* verify gives error messages itself */
 588                         verify_pack(p, 0);
 589
 590                 for (p = packed_git; p; p = p->next) {
 591                         uint32_t j, num;
 592                         if (open_pack_index(p))
 593                                 continue;
 594                         num = p->num_objects;
 595                         for (j = 0; j < num; j++)
 596                                 fsck_sha1(nth_packed_object_sha1(p, j));
 597                 }
 598         }
 599
 600         heads = 0;
 601         for (i = 1; i < argc; i++) {
 602                 const char *arg = argv[i];
 603                 if (!get_sha1(arg, head_sha1)) {
 604                         struct object *obj = lookup_object(head_sha1);
 605
 606                         /* Error is printed by lookup_object(). */
 607                         if (!obj)
 608                                 continue;
 609
 610                         obj->used = 1;
 611                         mark_object_reachable(obj);
 612                         heads++;
 613                         continue;
 614                 }
 615                 error("invalid parameter: expected sha1, got '%s'", arg);
 616         }
 617
 618         /*
 619          * If we've not been given any explicit head information, do the
 620          * default ones from .git/refs. We also consider the index file
 621          * in this case (ie this implies --cache).
 622          */
 623         if (!heads) {
 624                 get_default_heads();
 625                 keep_cache_objects = 1;
 626         }
 627
 628         if (keep_cache_objects) {
 629                 read_cache();
 630                 for (i = 0; i < active_nr; i++) {
 631                         unsigned int mode;
 632                         struct blob *blob;
 633                         struct object *obj;
 634
 635                         mode = active_cache[i]->ce_mode;
 636                         if (S_ISGITLINK(mode))
 637                                 continue;
 638                         blob = lookup_blob(active_cache[i]->sha1);
 639                         if (!blob)
 640                                 continue;
 641                         obj = &blob->object;
 642                         obj->used = 1;
 643                         mark_object_reachable(obj);
 644                 }
 645                 if (active_cache_tree)
 646                         fsck_cache_tree(active_cache_tree);
 647         }
 648
 649         check_connectivity();
 650         return errors_found;
 651 }