fsck.c

   1 #include "cache.h"
   2 #include "object.h"
   3 #include "blob.h"
   4 #include "tree.h"
   5 #include "tree-walk.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "fsck.h"
   9 #include "refs.h"
  10 #include "utf8.h"
  11 #include "sha1-array.h"
  12
  13 #define FSCK_FATAL -1
  14 #define FSCK_INFO -2
  15
  16 #define FOREACH_MSG_ID(FUNC) \
  17         /* fatal errors */ \
  18         FUNC(NUL_IN_HEADER, FATAL) \
  19         FUNC(UNTERMINATED_HEADER, FATAL) \
  20         /* errors */ \
  21         FUNC(BAD_DATE, ERROR) \
  22         FUNC(BAD_DATE_OVERFLOW, ERROR) \
  23         FUNC(BAD_EMAIL, ERROR) \
  24         FUNC(BAD_NAME, ERROR) \
  25         FUNC(BAD_OBJECT_SHA1, ERROR) \
  26         FUNC(BAD_PARENT_SHA1, ERROR) \
  27         FUNC(BAD_TAG_OBJECT, ERROR) \
  28         FUNC(BAD_TIMEZONE, ERROR) \
  29         FUNC(BAD_TREE, ERROR) \
  30         FUNC(BAD_TREE_SHA1, ERROR) \
  31         FUNC(BAD_TYPE, ERROR) \
  32         FUNC(DUPLICATE_ENTRIES, ERROR) \
  33         FUNC(MISSING_AUTHOR, ERROR) \
  34         FUNC(MISSING_COMMITTER, ERROR) \
  35         FUNC(MISSING_EMAIL, ERROR) \
  36         FUNC(MISSING_GRAFT, ERROR) \
  37         FUNC(MISSING_NAME_BEFORE_EMAIL, ERROR) \
  38         FUNC(MISSING_OBJECT, ERROR) \
  39         FUNC(MISSING_PARENT, ERROR) \
  40         FUNC(MISSING_SPACE_BEFORE_DATE, ERROR) \
  41         FUNC(MISSING_SPACE_BEFORE_EMAIL, ERROR) \
  42         FUNC(MISSING_TAG, ERROR) \
  43         FUNC(MISSING_TAG_ENTRY, ERROR) \
  44         FUNC(MISSING_TAG_OBJECT, ERROR) \
  45         FUNC(MISSING_TREE, ERROR) \
  46         FUNC(MISSING_TYPE, ERROR) \
  47         FUNC(MISSING_TYPE_ENTRY, ERROR) \
  48         FUNC(MULTIPLE_AUTHORS, ERROR) \
  49         FUNC(TAG_OBJECT_NOT_TAG, ERROR) \
  50         FUNC(TREE_NOT_SORTED, ERROR) \
  51         FUNC(UNKNOWN_TYPE, ERROR) \
  52         FUNC(ZERO_PADDED_DATE, ERROR) \
  53         /* warnings */ \
  54         FUNC(BAD_FILEMODE, WARN) \
  55         FUNC(EMPTY_NAME, WARN) \
  56         FUNC(FULL_PATHNAME, WARN) \
  57         FUNC(HAS_DOT, WARN) \
  58         FUNC(HAS_DOTDOT, WARN) \
  59         FUNC(HAS_DOTGIT, WARN) \
  60         FUNC(NULL_SHA1, WARN) \
  61         FUNC(ZERO_PADDED_FILEMODE, WARN) \
  62         /* infos (reported as warnings, but ignored by default) */ \
  63         FUNC(BAD_TAG_NAME, INFO) \
  64         FUNC(MISSING_TAGGER_ENTRY, INFO)
  65
  66 #define MSG_ID(id, msg_type) FSCK_MSG_##id,
  67 enum fsck_msg_id {
  68         FOREACH_MSG_ID(MSG_ID)
  69         FSCK_MSG_MAX
  70 };
  71 #undef MSG_ID
  72
  73 #define STR(x) #x
  74 #define MSG_ID(id, msg_type) { STR(id), NULL, FSCK_##msg_type },
  75 static struct {
  76         const char *id_string;
  77         const char *downcased;
  78         int msg_type;
  79 } msg_id_info[FSCK_MSG_MAX + 1] = {
  80         FOREACH_MSG_ID(MSG_ID)
  81         { NULL, NULL, -1 }
  82 };
  83 #undef MSG_ID
  84
  85 static int parse_msg_id(const char *text)
  86 {
  87         int i;
  88
  89         if (!msg_id_info[0].downcased) {
  90                 /* convert id_string to lower case, without underscores. */
  91                 for (i = 0; i < FSCK_MSG_MAX; i++) {
  92                         const char *p = msg_id_info[i].id_string;
  93                         int len = strlen(p);
  94                         char *q = xmalloc(len);
  95
  96                         msg_id_info[i].downcased = q;
  97                         while (*p)
  98                                 if (*p == '_')
  99                                         p++;
 100                                 else
 101                                         *(q)++ = tolower(*(p)++);
 102                         *q = '\0';
 103                 }
 104         }
 105
 106         for (i = 0; i < FSCK_MSG_MAX; i++)
 107                 if (!strcmp(text, msg_id_info[i].downcased))
 108                         return i;
 109
 110         return -1;
 111 }
 112
 113 static int fsck_msg_type(enum fsck_msg_id msg_id,
 114         struct fsck_options *options)
 115 {
 116         int msg_type;
 117
 118         assert(msg_id >= 0 && msg_id < FSCK_MSG_MAX);
 119
 120         if (options->msg_type)
 121                 msg_type = options->msg_type[msg_id];
 122         else {
 123                 msg_type = msg_id_info[msg_id].msg_type;
 124                 if (options->strict && msg_type == FSCK_WARN)
 125                         msg_type = FSCK_ERROR;
 126         }
 127
 128         return msg_type;
 129 }
 130
 131 static void init_skiplist(struct fsck_options *options, const char *path)
 132 {
 133         static struct sha1_array skiplist = SHA1_ARRAY_INIT;
 134         int sorted, fd;
 135         char buffer[41];
 136         unsigned char sha1[20];
 137
 138         if (options->skiplist)
 139                 sorted = options->skiplist->sorted;
 140         else {
 141                 sorted = 1;
 142                 options->skiplist = &skiplist;
 143         }
 144
 145         fd = open(path, O_RDONLY);
 146         if (fd < 0)
 147                 die("Could not open skip list: %s", path);
 148         for (;;) {
 149                 int result = read_in_full(fd, buffer, sizeof(buffer));
 150                 if (result < 0)
 151                         die_errno("Could not read '%s'", path);
 152                 if (!result)
 153                         break;
 154                 if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
 155                         die("Invalid SHA-1: %s", buffer);
 156                 sha1_array_append(&skiplist, sha1);
 157                 if (sorted && skiplist.nr > 1 &&
 158                                 hashcmp(skiplist.sha1[skiplist.nr - 2],
 159                                         sha1) > 0)
 160                         sorted = 0;
 161         }
 162         close(fd);
 163
 164         if (sorted)
 165                 skiplist.sorted = 1;
 166 }
 167
 168 static int parse_msg_type(const char *str)
 169 {
 170         if (!strcmp(str, "error"))
 171                 return FSCK_ERROR;
 172         else if (!strcmp(str, "warn"))
 173                 return FSCK_WARN;
 174         else if (!strcmp(str, "ignore"))
 175                 return FSCK_IGNORE;
 176         else
 177                 die("Unknown fsck message type: '%s'", str);
 178 }
 179
 180 int is_valid_msg_type(const char *msg_id, const char *msg_type)
 181 {
 182         if (parse_msg_id(msg_id) < 0)
 183                 return 0;
 184         parse_msg_type(msg_type);
 185         return 1;
 186 }
 187
 188 void fsck_set_msg_type(struct fsck_options *options,
 189                 const char *msg_id, const char *msg_type)
 190 {
 191         int id = parse_msg_id(msg_id), type;
 192
 193         if (id < 0)
 194                 die("Unhandled message id: %s", msg_id);
 195         type = parse_msg_type(msg_type);
 196
 197         if (type != FSCK_ERROR && msg_id_info[id].msg_type == FSCK_FATAL)
 198                 die("Cannot demote %s to %s", msg_id, msg_type);
 199
 200         if (!options->msg_type) {
 201                 int i;
 202                 int *msg_type = xmalloc(sizeof(int) * FSCK_MSG_MAX);
 203                 for (i = 0; i < FSCK_MSG_MAX; i++)
 204                         msg_type[i] = fsck_msg_type(i, options);
 205                 options->msg_type = msg_type;
 206         }
 207
 208         options->msg_type[id] = type;
 209 }
 210
 211 void fsck_set_msg_types(struct fsck_options *options, const char *values)
 212 {
 213         char *buf = xstrdup(values), *to_free = buf;
 214         int done = 0;
 215
 216         while (!done) {
 217                 int len = strcspn(buf, " ,|"), equal;
 218
 219                 done = !buf[len];
 220                 if (!len) {
 221                         buf++;
 222                         continue;
 223                 }
 224                 buf[len] = '\0';
 225
 226                 for (equal = 0;
 227                      equal < len && buf[equal] != '=' && buf[equal] != ':';
 228                      equal++)
 229                         buf[equal] = tolower(buf[equal]);
 230                 buf[equal] = '\0';
 231
 232                 if (!strcmp(buf, "skiplist")) {
 233                         if (equal == len)
 234                                 die("skiplist requires a path");
 235                         init_skiplist(options, buf + equal + 1);
 236                         buf += len + 1;
 237                         continue;
 238                 }
 239
 240                 if (equal == len)
 241                         die("Missing '=': '%s'", buf);
 242
 243                 fsck_set_msg_type(options, buf, buf + equal + 1);
 244                 buf += len + 1;
 245         }
 246         free(to_free);
 247 }
 248
 249 static void append_msg_id(struct strbuf *sb, const char *msg_id)
 250 {
 251         for (;;) {
 252                 char c = *(msg_id)++;
 253
 254                 if (!c)
 255                         break;
 256                 if (c != '_')
 257                         strbuf_addch(sb, tolower(c));
 258                 else {
 259                         assert(*msg_id);
 260                         strbuf_addch(sb, *(msg_id)++);
 261                 }
 262         }
 263
 264         strbuf_addstr(sb, ": ");
 265 }
 266
 267 __attribute__((format (printf, 4, 5)))
 268 static int report(struct fsck_options *options, struct object *object,
 269         enum fsck_msg_id id, const char *fmt, ...)
 270 {
 271         va_list ap;
 272         struct strbuf sb = STRBUF_INIT;
 273         int msg_type = fsck_msg_type(id, options), result;
 274
 275         if (msg_type == FSCK_IGNORE)
 276                 return 0;
 277
 278         if (options->skiplist && object &&
 279                         sha1_array_lookup(options->skiplist, object->oid.hash) >= 0)
 280                 return 0;
 281
 282         if (msg_type == FSCK_FATAL)
 283                 msg_type = FSCK_ERROR;
 284         else if (msg_type == FSCK_INFO)
 285                 msg_type = FSCK_WARN;
 286
 287         append_msg_id(&sb, msg_id_info[id].id_string);
 288
 289         va_start(ap, fmt);
 290         strbuf_vaddf(&sb, fmt, ap);
 291         result = options->error_func(object, msg_type, sb.buf);
 292         strbuf_release(&sb);
 293         va_end(ap);
 294
 295         return result;
 296 }
 297
 298 static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *options)
 299 {
 300         struct tree_desc desc;
 301         struct name_entry entry;
 302         int res = 0;
 303
 304         if (parse_tree(tree))
 305                 return -1;
 306
 307         init_tree_desc(&desc, tree->buffer, tree->size);
 308         while (tree_entry(&desc, &entry)) {
 309                 int result;
 310
 311                 if (S_ISGITLINK(entry.mode))
 312                         continue;
 313                 if (S_ISDIR(entry.mode))
 314                         result = options->walk(&lookup_tree(entry.sha1)->object, OBJ_TREE, data, options);
 315                 else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
 316                         result = options->walk(&lookup_blob(entry.sha1)->object, OBJ_BLOB, data, options);
 317                 else {
 318                         result = error("in tree %s: entry %s has bad mode %.6o",
 319                                         oid_to_hex(&tree->object.oid), entry.path, entry.mode);
 320                 }
 321                 if (result < 0)
 322                         return result;
 323                 if (!res)
 324                         res = result;
 325         }
 326         return res;
 327 }
 328
 329 static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_options *options)
 330 {
 331         struct commit_list *parents;
 332         int res;
 333         int result;
 334
 335         if (parse_commit(commit))
 336                 return -1;
 337
 338         result = options->walk((struct object *)commit->tree, OBJ_TREE, data, options);
 339         if (result < 0)
 340                 return result;
 341         res = result;
 342
 343         parents = commit->parents;
 344         while (parents) {
 345                 result = options->walk((struct object *)parents->item, OBJ_COMMIT, data, options);
 346                 if (result < 0)
 347                         return result;
 348                 if (!res)
 349                         res = result;
 350                 parents = parents->next;
 351         }
 352         return res;
 353 }
 354
 355 static int fsck_walk_tag(struct tag *tag, void *data, struct fsck_options *options)
 356 {
 357         if (parse_tag(tag))
 358                 return -1;
 359         return options->walk(tag->tagged, OBJ_ANY, data, options);
 360 }
 361
 362 int fsck_walk(struct object *obj, void *data, struct fsck_options *options)
 363 {
 364         if (!obj)
 365                 return -1;
 366         switch (obj->type) {
 367         case OBJ_BLOB:
 368                 return 0;
 369         case OBJ_TREE:
 370                 return fsck_walk_tree((struct tree *)obj, data, options);
 371         case OBJ_COMMIT:
 372                 return fsck_walk_commit((struct commit *)obj, data, options);
 373         case OBJ_TAG:
 374                 return fsck_walk_tag((struct tag *)obj, data, options);
 375         default:
 376                 error("Unknown object type for %s", oid_to_hex(&obj->oid));
 377                 return -1;
 378         }
 379 }
 380
 381 /*
 382  * The entries in a tree are ordered in the _path_ order,
 383  * which means that a directory entry is ordered by adding
 384  * a slash to the end of it.
 385  *
 386  * So a directory called "a" is ordered _after_ a file
 387  * called "a.c", because "a/" sorts after "a.c".
 388  */
 389 #define TREE_UNORDERED (-1)
 390 #define TREE_HAS_DUPS  (-2)
 391
 392 static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 393 {
 394         int len1 = strlen(name1);
 395         int len2 = strlen(name2);
 396         int len = len1 < len2 ? len1 : len2;
 397         unsigned char c1, c2;
 398         int cmp;
 399
 400         cmp = memcmp(name1, name2, len);
 401         if (cmp < 0)
 402                 return 0;
 403         if (cmp > 0)
 404                 return TREE_UNORDERED;
 405
 406         /*
 407          * Ok, the first <len> characters are the same.
 408          * Now we need to order the next one, but turn
 409          * a '\0' into a '/' for a directory entry.
 410          */
 411         c1 = name1[len];
 412         c2 = name2[len];
 413         if (!c1 && !c2)
 414                 /*
 415                  * git-write-tree used to write out a nonsense tree that has
 416                  * entries with the same name, one blob and one tree.  Make
 417                  * sure we do not have duplicate entries.
 418                  */
 419                 return TREE_HAS_DUPS;
 420         if (!c1 && S_ISDIR(mode1))
 421                 c1 = '/';
 422         if (!c2 && S_ISDIR(mode2))
 423                 c2 = '/';
 424         return c1 < c2 ? 0 : TREE_UNORDERED;
 425 }
 426
 427 static int fsck_tree(struct tree *item, struct fsck_options *options)
 428 {
 429         int retval;
 430         int has_null_sha1 = 0;
 431         int has_full_path = 0;
 432         int has_empty_name = 0;
 433         int has_dot = 0;
 434         int has_dotdot = 0;
 435         int has_dotgit = 0;
 436         int has_zero_pad = 0;
 437         int has_bad_modes = 0;
 438         int has_dup_entries = 0;
 439         int not_properly_sorted = 0;
 440         struct tree_desc desc;
 441         unsigned o_mode;
 442         const char *o_name;
 443
 444         init_tree_desc(&desc, item->buffer, item->size);
 445
 446         o_mode = 0;
 447         o_name = NULL;
 448
 449         while (desc.size) {
 450                 unsigned mode;
 451                 const char *name;
 452                 const unsigned char *sha1;
 453
 454                 sha1 = tree_entry_extract(&desc, &name, &mode);
 455
 456                 has_null_sha1 |= is_null_sha1(sha1);
 457                 has_full_path |= !!strchr(name, '/');
 458                 has_empty_name |= !*name;
 459                 has_dot |= !strcmp(name, ".");
 460                 has_dotdot |= !strcmp(name, "..");
 461                 has_dotgit |= (!strcmp(name, ".git") ||
 462                                is_hfs_dotgit(name) ||
 463                                is_ntfs_dotgit(name));
 464                 has_zero_pad |= *(char *)desc.buffer == '0';
 465                 update_tree_entry(&desc);
 466
 467                 switch (mode) {
 468                 /*
 469                  * Standard modes..
 470                  */
 471                 case S_IFREG | 0755:
 472                 case S_IFREG | 0644:
 473                 case S_IFLNK:
 474                 case S_IFDIR:
 475                 case S_IFGITLINK:
 476                         break;
 477                 /*
 478                  * This is nonstandard, but we had a few of these
 479                  * early on when we honored the full set of mode
 480                  * bits..
 481                  */
 482                 case S_IFREG | 0664:
 483                         if (!options->strict)
 484                                 break;
 485                 default:
 486                         has_bad_modes = 1;
 487                 }
 488
 489                 if (o_name) {
 490                         switch (verify_ordered(o_mode, o_name, mode, name)) {
 491                         case TREE_UNORDERED:
 492                                 not_properly_sorted = 1;
 493                                 break;
 494                         case TREE_HAS_DUPS:
 495                                 has_dup_entries = 1;
 496                                 break;
 497                         default:
 498                                 break;
 499                         }
 500                 }
 501
 502                 o_mode = mode;
 503                 o_name = name;
 504         }
 505
 506         retval = 0;
 507         if (has_null_sha1)
 508                 retval += report(options, &item->object, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
 509         if (has_full_path)
 510                 retval += report(options, &item->object, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
 511         if (has_empty_name)
 512                 retval += report(options, &item->object, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
 513         if (has_dot)
 514                 retval += report(options, &item->object, FSCK_MSG_HAS_DOT, "contains '.'");
 515         if (has_dotdot)
 516                 retval += report(options, &item->object, FSCK_MSG_HAS_DOTDOT, "contains '..'");
 517         if (has_dotgit)
 518                 retval += report(options, &item->object, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
 519         if (has_zero_pad)
 520                 retval += report(options, &item->object, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
 521         if (has_bad_modes)
 522                 retval += report(options, &item->object, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
 523         if (has_dup_entries)
 524                 retval += report(options, &item->object, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
 525         if (not_properly_sorted)
 526                 retval += report(options, &item->object, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
 527         return retval;
 528 }
 529
 530 static int verify_headers(const void *data, unsigned long size,
 531                           struct object *obj, struct fsck_options *options)
 532 {
 533         const char *buffer = (const char *)data;
 534         unsigned long i;
 535
 536         for (i = 0; i < size; i++) {
 537                 switch (buffer[i]) {
 538                 case '\0':
 539                         return report(options, obj,
 540                                 FSCK_MSG_NUL_IN_HEADER,
 541                                 "unterminated header: NUL at offset %ld", i);
 542                 case '\n':
 543                         if (i + 1 < size && buffer[i + 1] == '\n')
 544                                 return 0;
 545                 }
 546         }
 547
 548         /*
 549          * We did not find double-LF that separates the header
 550          * and the body.  Not having a body is not a crime but
 551          * we do want to see the terminating LF for the last header
 552          * line.
 553          */
 554         if (size && buffer[size - 1] == '\n')
 555                 return 0;
 556
 557         return report(options, obj,
 558                 FSCK_MSG_UNTERMINATED_HEADER, "unterminated header");
 559 }
 560
 561 static int fsck_ident(const char **ident, struct object *obj, struct fsck_options *options)
 562 {
 563         const char *p = *ident;
 564         char *end;
 565
 566         *ident = strchrnul(*ident, '\n');
 567         if (**ident == '\n')
 568                 (*ident)++;
 569
 570         if (*p == '<')
 571                 return report(options, obj, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 572         p += strcspn(p, "<>\n");
 573         if (*p == '>')
 574                 return report(options, obj, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
 575         if (*p != '<')
 576                 return report(options, obj, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
 577         if (p[-1] != ' ')
 578                 return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 579         p++;
 580         p += strcspn(p, "<>\n");
 581         if (*p != '>')
 582                 return report(options, obj, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
 583         p++;
 584         if (*p != ' ')
 585                 return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
 586         p++;
 587         if (*p == '0' && p[1] != ' ')
 588                 return report(options, obj, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
 589         if (date_overflows(strtoul(p, &end, 10)))
 590                 return report(options, obj, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
 591         if ((end == p || *end != ' '))
 592                 return report(options, obj, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
 593         p = end + 1;
 594         if ((*p != '+' && *p != '-') ||
 595             !isdigit(p[1]) ||
 596             !isdigit(p[2]) ||
 597             !isdigit(p[3]) ||
 598             !isdigit(p[4]) ||
 599             (p[5] != '\n'))
 600                 return report(options, obj, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
 601         p += 6;
 602         return 0;
 603 }
 604
 605 static int fsck_commit_buffer(struct commit *commit, const char *buffer,
 606         unsigned long size, struct fsck_options *options)
 607 {
 608         unsigned char tree_sha1[20], sha1[20];
 609         struct commit_graft *graft;
 610         unsigned parent_count, parent_line_count = 0, author_count;
 611         int err;
 612
 613         if (verify_headers(buffer, size, &commit->object, options))
 614                 return -1;
 615
 616         if (!skip_prefix(buffer, "tree ", &buffer))
 617                 return report(options, &commit->object, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
 618         if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n') {
 619                 err = report(options, &commit->object, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
 620                 if (err)
 621                         return err;
 622         }
 623         buffer += 41;
 624         while (skip_prefix(buffer, "parent ", &buffer)) {
 625                 if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
 626                         err = report(options, &commit->object, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
 627                         if (err)
 628                                 return err;
 629                 }
 630                 buffer += 41;
 631                 parent_line_count++;
 632         }
 633         graft = lookup_commit_graft(commit->object.oid.hash);
 634         parent_count = commit_list_count(commit->parents);
 635         if (graft) {
 636                 if (graft->nr_parent == -1 && !parent_count)
 637                         ; /* shallow commit */
 638                 else if (graft->nr_parent != parent_count) {
 639                         err = report(options, &commit->object, FSCK_MSG_MISSING_GRAFT, "graft objects missing");
 640                         if (err)
 641                                 return err;
 642                 }
 643         } else {
 644                 if (parent_count != parent_line_count) {
 645                         err = report(options, &commit->object, FSCK_MSG_MISSING_PARENT, "parent objects missing");
 646                         if (err)
 647                                 return err;
 648                 }
 649         }
 650         author_count = 0;
 651         while (skip_prefix(buffer, "author ", &buffer)) {
 652                 author_count++;
 653                 err = fsck_ident(&buffer, &commit->object, options);
 654                 if (err)
 655                         return err;
 656         }
 657         if (author_count < 1)
 658                 err = report(options, &commit->object, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
 659         else if (author_count > 1)
 660                 err = report(options, &commit->object, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
 661         if (err)
 662                 return err;
 663         if (!skip_prefix(buffer, "committer ", &buffer))
 664                 return report(options, &commit->object, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
 665         err = fsck_ident(&buffer, &commit->object, options);
 666         if (err)
 667                 return err;
 668         if (!commit->tree)
 669                 return report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
 670
 671         return 0;
 672 }
 673
 674 static int fsck_commit(struct commit *commit, const char *data,
 675         unsigned long size, struct fsck_options *options)
 676 {
 677         const char *buffer = data ?  data : get_commit_buffer(commit, &size);
 678         int ret = fsck_commit_buffer(commit, buffer, size, options);
 679         if (!data)
 680                 unuse_commit_buffer(commit, buffer);
 681         return ret;
 682 }
 683
 684 static int fsck_tag_buffer(struct tag *tag, const char *data,
 685         unsigned long size, struct fsck_options *options)
 686 {
 687         unsigned char sha1[20];
 688         int ret = 0;
 689         const char *buffer;
 690         char *to_free = NULL, *eol;
 691         struct strbuf sb = STRBUF_INIT;
 692
 693         if (data)
 694                 buffer = data;
 695         else {
 696                 enum object_type type;
 697
 698                 buffer = to_free =
 699                         read_sha1_file(tag->object.oid.hash, &type, &size);
 700                 if (!buffer)
 701                         return report(options, &tag->object,
 702                                 FSCK_MSG_MISSING_TAG_OBJECT,
 703                                 "cannot read tag object");
 704
 705                 if (type != OBJ_TAG) {
 706                         ret = report(options, &tag->object,
 707                                 FSCK_MSG_TAG_OBJECT_NOT_TAG,
 708                                 "expected tag got %s",
 709                             typename(type));
 710                         goto done;
 711                 }
 712         }
 713
 714         ret = verify_headers(buffer, size, &tag->object, options);
 715         if (ret)
 716                 goto done;
 717
 718         if (!skip_prefix(buffer, "object ", &buffer)) {
 719                 ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 720                 goto done;
 721         }
 722         if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
 723                 ret = report(options, &tag->object, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
 724                 if (ret)
 725                         goto done;
 726         }
 727         buffer += 41;
 728
 729         if (!skip_prefix(buffer, "type ", &buffer)) {
 730                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
 731                 goto done;
 732         }
 733         eol = strchr(buffer, '\n');
 734         if (!eol) {
 735                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
 736                 goto done;
 737         }
 738         if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
 739                 ret = report(options, &tag->object, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
 740         if (ret)
 741                 goto done;
 742         buffer = eol + 1;
 743
 744         if (!skip_prefix(buffer, "tag ", &buffer)) {
 745                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
 746                 goto done;
 747         }
 748         eol = strchr(buffer, '\n');
 749         if (!eol) {
 750                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
 751                 goto done;
 752         }
 753         strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
 754         if (check_refname_format(sb.buf, 0)) {
 755                 ret = report(options, &tag->object, FSCK_MSG_BAD_TAG_NAME,
 756                            "invalid 'tag' name: %.*s",
 757                            (int)(eol - buffer), buffer);
 758                 if (ret)
 759                         goto done;
 760         }
 761         buffer = eol + 1;
 762
 763         if (!skip_prefix(buffer, "tagger ", &buffer)) {
 764                 /* early tags do not contain 'tagger' lines; warn only */
 765                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
 766                 if (ret)
 767                         goto done;
 768         }
 769         else
 770                 ret = fsck_ident(&buffer, &tag->object, options);
 771
 772 done:
 773         strbuf_release(&sb);
 774         free(to_free);
 775         return ret;
 776 }
 777
 778 static int fsck_tag(struct tag *tag, const char *data,
 779         unsigned long size, struct fsck_options *options)
 780 {
 781         struct object *tagged = tag->tagged;
 782
 783         if (!tagged)
 784                 return report(options, &tag->object, FSCK_MSG_BAD_TAG_OBJECT, "could not load tagged object");
 785
 786         return fsck_tag_buffer(tag, data, size, options);
 787 }
 788
 789 int fsck_object(struct object *obj, void *data, unsigned long size,
 790         struct fsck_options *options)
 791 {
 792         if (!obj)
 793                 return report(options, obj, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
 794
 795         if (obj->type == OBJ_BLOB)
 796                 return 0;
 797         if (obj->type == OBJ_TREE)
 798                 return fsck_tree((struct tree *) obj, options);
 799         if (obj->type == OBJ_COMMIT)
 800                 return fsck_commit((struct commit *) obj, (const char *) data,
 801                         size, options);
 802         if (obj->type == OBJ_TAG)
 803                 return fsck_tag((struct tag *) obj, (const char *) data,
 804                         size, options);
 805
 806         return report(options, obj, FSCK_MSG_UNKNOWN_TYPE, "unknown type '%d' (internal fsck error)",
 807                           obj->type);
 808 }
 809
 810 int fsck_error_function(struct object *obj, int msg_type, const char *message)
 811 {
 812         if (msg_type == FSCK_WARN) {
 813                 warning("object %s: %s", oid_to_hex(&obj->oid), message);
 814                 return 0;
 815         }
 816         error("object %s: %s", oid_to_hex(&obj->oid), message);
 817         return 1;
 818 }