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                 if (prefixcmp(de->d_name, "tmp_obj_"))
 389                         continue;
 390                 fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
 391         }
 392         closedir(dir);
 393 }
 394
 395 static int default_refs;
 396
 397 static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 398                 const char *email, unsigned long timestamp, int tz,
 399                 const char *message, void *cb_data)
 400 {
 401         struct object *obj;
 402
 403         if (verbose)
 404                 fprintf(stderr, "Checking reflog %s->%s\n",
 405                         sha1_to_hex(osha1), sha1_to_hex(nsha1));
 406
 407         if (!is_null_sha1(osha1)) {
 408                 obj = lookup_object(osha1);
 409                 if (obj) {
 410                         obj->used = 1;
 411                         mark_object_reachable(obj);
 412                 }
 413         }
 414         obj = lookup_object(nsha1);
 415         if (obj) {
 416                 obj->used = 1;
 417                 mark_object_reachable(obj);
 418         }
 419         return 0;
 420 }
 421
 422 static int fsck_handle_reflog(const char *logname, const unsigned char *sha1, int flag, void *cb_data)
 423 {
 424         for_each_reflog_ent(logname, fsck_handle_reflog_ent, NULL);
 425         return 0;
 426 }
 427
 428 static int is_branch(const char *refname)
 429 {
 430         return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
 431 }
 432
 433 static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 434 {
 435         struct object *obj;
 436
 437         obj = parse_object(sha1);
 438         if (!obj) {
 439                 error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
 440                 /* We'll continue with the rest despite the error.. */
 441                 return 0;
 442         }
 443         if (obj->type != OBJ_COMMIT && is_branch(refname))
 444                 error("%s: not a commit", refname);
 445         default_refs++;
 446         obj->used = 1;
 447         mark_object_reachable(obj);
 448
 449         return 0;
 450 }
 451
 452 static void get_default_heads(void)
 453 {
 454         for_each_ref(fsck_handle_ref, NULL);
 455         if (include_reflogs)
 456                 for_each_reflog(fsck_handle_reflog, NULL);
 457
 458         /*
 459          * Not having any default heads isn't really fatal, but
 460          * it does mean that "--unreachable" no longer makes any
 461          * sense (since in this case everything will obviously
 462          * be unreachable by definition.
 463          *
 464          * Showing dangling objects is valid, though (as those
 465          * dangling objects are likely lost heads).
 466          *
 467          * So we just print a warning about it, and clear the
 468          * "show_unreachable" flag.
 469          */
 470         if (!default_refs) {
 471                 fprintf(stderr, "notice: No default references\n");
 472                 show_unreachable = 0;
 473         }
 474 }
 475
 476 static void fsck_object_dir(const char *path)
 477 {
 478         int i;
 479
 480         if (verbose)
 481                 fprintf(stderr, "Checking object directory\n");
 482
 483         for (i = 0; i < 256; i++) {
 484                 static char dir[4096];
 485                 sprintf(dir, "%s/%02x", path, i);
 486                 fsck_dir(i, dir);
 487         }
 488         fsck_sha1_list();
 489 }
 490
 491 static int fsck_head_link(void)
 492 {
 493         unsigned char sha1[20];
 494         int flag;
 495         int null_is_error = 0;
 496         const char *head_points_at = resolve_ref("HEAD", sha1, 0, &flag);
 497
 498         if (verbose)
 499                 fprintf(stderr, "Checking HEAD link\n");
 500
 501         if (!head_points_at)
 502                 return error("Invalid HEAD");
 503         if (!strcmp(head_points_at, "HEAD"))
 504                 /* detached HEAD */
 505                 null_is_error = 1;
 506         else if (prefixcmp(head_points_at, "refs/heads/"))
 507                 return error("HEAD points to something strange (%s)",
 508                              head_points_at);
 509         if (is_null_sha1(sha1)) {
 510                 if (null_is_error)
 511                         return error("HEAD: detached HEAD points at nothing");
 512                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
 513                         head_points_at + 11);
 514         }
 515         return 0;
 516 }
 517
 518 static int fsck_cache_tree(struct cache_tree *it)
 519 {
 520         int i;
 521         int err = 0;
 522
 523         if (verbose)
 524                 fprintf(stderr, "Checking cache tree\n");
 525
 526         if (0 <= it->entry_count) {
 527                 struct object *obj = parse_object(it->sha1);
 528                 if (!obj) {
 529                         error("%s: invalid sha1 pointer in cache-tree",
 530                               sha1_to_hex(it->sha1));
 531                         return 1;
 532                 }
 533                 mark_object_reachable(obj);
 534                 obj->used = 1;
 535                 if (obj->type != OBJ_TREE)
 536                         err |= objerror(obj, "non-tree in cache-tree");
 537         }
 538         for (i = 0; i < it->subtree_nr; i++)
 539                 err |= fsck_cache_tree(it->down[i]->cache_tree);
 540         return err;
 541 }
 542
 543 static char const * const fsck_usage[] = {
 544         "git fsck [options] [<object>...]",
 545         NULL
 546 };
 547
 548 static struct option fsck_opts[] = {
 549         OPT__VERBOSE(&verbose),
 550         OPT_BOOLEAN(0, "unreachable", &show_unreachable, "show unreachable objects"),
 551         OPT_BOOLEAN(0, "tags", &show_tags, "report tags"),
 552         OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 553         OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 554         OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
 555         OPT_BOOLEAN(0, "full", &check_full, "also consider alternate objects"),
 556         OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 557         OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 558                                 "write dangling objects in .git/lost-found"),
 559         OPT_END(),
 560 };
 561
 562 int cmd_fsck(int argc, const char **argv, const char *prefix)
 563 {
 564         int i, heads;
 565
 566         errors_found = 0;
 567
 568         argc = parse_options(argc, argv, fsck_opts, fsck_usage, 0);
 569         if (write_lost_and_found) {
 570                 check_full = 1;
 571                 include_reflogs = 0;
 572         }
 573
 574         fsck_head_link();
 575         fsck_object_dir(get_object_directory());
 576         if (check_full) {
 577                 struct alternate_object_database *alt;
 578                 struct packed_git *p;
 579                 prepare_alt_odb();
 580                 for (alt = alt_odb_list; alt; alt = alt->next) {
 581                         char namebuf[PATH_MAX];
 582                         int namelen = alt->name - alt->base;
 583                         memcpy(namebuf, alt->base, namelen);
 584                         namebuf[namelen - 1] = 0;
 585                         fsck_object_dir(namebuf);
 586                 }
 587                 prepare_packed_git();
 588                 for (p = packed_git; p; p = p->next)
 589                         /* verify gives error messages itself */
 590                         verify_pack(p);
 591
 592                 for (p = packed_git; p; p = p->next) {
 593                         uint32_t j, num;
 594                         if (open_pack_index(p))
 595                                 continue;
 596                         num = p->num_objects;
 597                         for (j = 0; j < num; j++)
 598                                 fsck_sha1(nth_packed_object_sha1(p, j));
 599                 }
 600         }
 601
 602         heads = 0;
 603         for (i = 1; i < argc; i++) {
 604                 const char *arg = argv[i];
 605                 if (!get_sha1(arg, head_sha1)) {
 606                         struct object *obj = lookup_object(head_sha1);
 607
 608                         /* Error is printed by lookup_object(). */
 609                         if (!obj)
 610                                 continue;
 611
 612                         obj->used = 1;
 613                         mark_object_reachable(obj);
 614                         heads++;
 615                         continue;
 616                 }
 617                 error("invalid parameter: expected sha1, got '%s'", arg);
 618         }
 619
 620         /*
 621          * If we've not been given any explicit head information, do the
 622          * default ones from .git/refs. We also consider the index file
 623          * in this case (ie this implies --cache).
 624          */
 625         if (!heads) {
 626                 get_default_heads();
 627                 keep_cache_objects = 1;
 628         }
 629
 630         if (keep_cache_objects) {
 631                 read_cache();
 632                 for (i = 0; i < active_nr; i++) {
 633                         unsigned int mode;
 634                         struct blob *blob;
 635                         struct object *obj;
 636
 637                         mode = active_cache[i]->ce_mode;
 638                         if (S_ISGITLINK(mode))
 639                                 continue;
 640                         blob = lookup_blob(active_cache[i]->sha1);
 641                         if (!blob)
 642                                 continue;
 643                         obj = &blob->object;
 644                         obj->used = 1;
 645                         mark_object_reachable(obj);
 646                 }
 647                 if (active_cache_tree)
 648                         fsck_cache_tree(active_cache_tree);
 649         }
 650
 651         check_connectivity();
 652         return errors_found;
 653 }