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         FUNC(NUL_IN_COMMIT, WARN) \
  63         /* infos (reported as warnings, but ignored by default) */ \
  64         FUNC(BAD_TAG_NAME, INFO) \
  65         FUNC(MISSING_TAGGER_ENTRY, INFO)
  66
  67 #define MSG_ID(id, msg_type) FSCK_MSG_##id,
  68 enum fsck_msg_id {
  69         FOREACH_MSG_ID(MSG_ID)
  70         FSCK_MSG_MAX
  71 };
  72 #undef MSG_ID
  73
  74 #define STR(x) #x
  75 #define MSG_ID(id, msg_type) { STR(id), NULL, FSCK_##msg_type },
  76 static struct {
  77         const char *id_string;
  78         const char *downcased;
  79         int msg_type;
  80 } msg_id_info[FSCK_MSG_MAX + 1] = {
  81         FOREACH_MSG_ID(MSG_ID)
  82         { NULL, NULL, -1 }
  83 };
  84 #undef MSG_ID
  85
  86 static int parse_msg_id(const char *text)
  87 {
  88         int i;
  89
  90         if (!msg_id_info[0].downcased) {
  91                 /* convert id_string to lower case, without underscores. */
  92                 for (i = 0; i < FSCK_MSG_MAX; i++) {
  93                         const char *p = msg_id_info[i].id_string;
  94                         int len = strlen(p);
  95                         char *q = xmalloc(len);
  96
  97                         msg_id_info[i].downcased = q;
  98                         while (*p)
  99                                 if (*p == '_')
 100                                         p++;
 101                                 else
 102                                         *(q)++ = tolower(*(p)++);
 103                         *q = '\0';
 104                 }
 105         }
 106
 107         for (i = 0; i < FSCK_MSG_MAX; i++)
 108                 if (!strcmp(text, msg_id_info[i].downcased))
 109                         return i;
 110
 111         return -1;
 112 }
 113
 114 static int fsck_msg_type(enum fsck_msg_id msg_id,
 115         struct fsck_options *options)
 116 {
 117         int msg_type;
 118
 119         assert(msg_id >= 0 && msg_id < FSCK_MSG_MAX);
 120
 121         if (options->msg_type)
 122                 msg_type = options->msg_type[msg_id];
 123         else {
 124                 msg_type = msg_id_info[msg_id].msg_type;
 125                 if (options->strict && msg_type == FSCK_WARN)
 126                         msg_type = FSCK_ERROR;
 127         }
 128
 129         return msg_type;
 130 }
 131
 132 static void init_skiplist(struct fsck_options *options, const char *path)
 133 {
 134         static struct sha1_array skiplist = SHA1_ARRAY_INIT;
 135         int sorted, fd;
 136         char buffer[41];
 137         unsigned char sha1[20];
 138
 139         if (options->skiplist)
 140                 sorted = options->skiplist->sorted;
 141         else {
 142                 sorted = 1;
 143                 options->skiplist = &skiplist;
 144         }
 145
 146         fd = open(path, O_RDONLY);
 147         if (fd < 0)
 148                 die("Could not open skip list: %s", path);
 149         for (;;) {
 150                 int result = read_in_full(fd, buffer, sizeof(buffer));
 151                 if (result < 0)
 152                         die_errno("Could not read '%s'", path);
 153                 if (!result)
 154                         break;
 155                 if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
 156                         die("Invalid SHA-1: %s", buffer);
 157                 sha1_array_append(&skiplist, sha1);
 158                 if (sorted && skiplist.nr > 1 &&
 159                                 hashcmp(skiplist.sha1[skiplist.nr - 2],
 160                                         sha1) > 0)
 161                         sorted = 0;
 162         }
 163         close(fd);
 164
 165         if (sorted)
 166                 skiplist.sorted = 1;
 167 }
 168
 169 static int parse_msg_type(const char *str)
 170 {
 171         if (!strcmp(str, "error"))
 172                 return FSCK_ERROR;
 173         else if (!strcmp(str, "warn"))
 174                 return FSCK_WARN;
 175         else if (!strcmp(str, "ignore"))
 176                 return FSCK_IGNORE;
 177         else
 178                 die("Unknown fsck message type: '%s'", str);
 179 }
 180
 181 int is_valid_msg_type(const char *msg_id, const char *msg_type)
 182 {
 183         if (parse_msg_id(msg_id) < 0)
 184                 return 0;
 185         parse_msg_type(msg_type);
 186         return 1;
 187 }
 188
 189 void fsck_set_msg_type(struct fsck_options *options,
 190                 const char *msg_id, const char *msg_type)
 191 {
 192         int id = parse_msg_id(msg_id), type;
 193
 194         if (id < 0)
 195                 die("Unhandled message id: %s", msg_id);
 196         type = parse_msg_type(msg_type);
 197
 198         if (type != FSCK_ERROR && msg_id_info[id].msg_type == FSCK_FATAL)
 199                 die("Cannot demote %s to %s", msg_id, msg_type);
 200
 201         if (!options->msg_type) {
 202                 int i;
 203                 int *msg_type;
 204                 ALLOC_ARRAY(msg_type, FSCK_MSG_MAX);
 205                 for (i = 0; i < FSCK_MSG_MAX; i++)
 206                         msg_type[i] = fsck_msg_type(i, options);
 207                 options->msg_type = msg_type;
 208         }
 209
 210         options->msg_type[id] = type;
 211 }
 212
 213 void fsck_set_msg_types(struct fsck_options *options, const char *values)
 214 {
 215         char *buf = xstrdup(values), *to_free = buf;
 216         int done = 0;
 217
 218         while (!done) {
 219                 int len = strcspn(buf, " ,|"), equal;
 220
 221                 done = !buf[len];
 222                 if (!len) {
 223                         buf++;
 224                         continue;
 225                 }
 226                 buf[len] = '\0';
 227
 228                 for (equal = 0;
 229                      equal < len && buf[equal] != '=' && buf[equal] != ':';
 230                      equal++)
 231                         buf[equal] = tolower(buf[equal]);
 232                 buf[equal] = '\0';
 233
 234                 if (!strcmp(buf, "skiplist")) {
 235                         if (equal == len)
 236                                 die("skiplist requires a path");
 237                         init_skiplist(options, buf + equal + 1);
 238                         buf += len + 1;
 239                         continue;
 240                 }
 241
 242                 if (equal == len)
 243                         die("Missing '=': '%s'", buf);
 244
 245                 fsck_set_msg_type(options, buf, buf + equal + 1);
 246                 buf += len + 1;
 247         }
 248         free(to_free);
 249 }
 250
 251 static void append_msg_id(struct strbuf *sb, const char *msg_id)
 252 {
 253         for (;;) {
 254                 char c = *(msg_id)++;
 255
 256                 if (!c)
 257                         break;
 258                 if (c != '_')
 259                         strbuf_addch(sb, tolower(c));
 260                 else {
 261                         assert(*msg_id);
 262                         strbuf_addch(sb, *(msg_id)++);
 263                 }
 264         }
 265
 266         strbuf_addstr(sb, ": ");
 267 }
 268
 269 __attribute__((format (printf, 4, 5)))
 270 static int report(struct fsck_options *options, struct object *object,
 271         enum fsck_msg_id id, const char *fmt, ...)
 272 {
 273         va_list ap;
 274         struct strbuf sb = STRBUF_INIT;
 275         int msg_type = fsck_msg_type(id, options), result;
 276
 277         if (msg_type == FSCK_IGNORE)
 278                 return 0;
 279
 280         if (options->skiplist && object &&
 281                         sha1_array_lookup(options->skiplist, object->oid.hash) >= 0)
 282                 return 0;
 283
 284         if (msg_type == FSCK_FATAL)
 285                 msg_type = FSCK_ERROR;
 286         else if (msg_type == FSCK_INFO)
 287                 msg_type = FSCK_WARN;
 288
 289         append_msg_id(&sb, msg_id_info[id].id_string);
 290
 291         va_start(ap, fmt);
 292         strbuf_vaddf(&sb, fmt, ap);
 293         result = options->error_func(object, msg_type, sb.buf);
 294         strbuf_release(&sb);
 295         va_end(ap);
 296
 297         return result;
 298 }
 299
 300 static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *options)
 301 {
 302         struct tree_desc desc;
 303         struct name_entry entry;
 304         int res = 0;
 305
 306         if (parse_tree(tree))
 307                 return -1;
 308
 309         init_tree_desc(&desc, tree->buffer, tree->size);
 310         while (tree_entry(&desc, &entry)) {
 311                 int result;
 312
 313                 if (S_ISGITLINK(entry.mode))
 314                         continue;
 315                 if (S_ISDIR(entry.mode))
 316                         result = options->walk(&lookup_tree(entry.oid->hash)->object, OBJ_TREE, data, options);
 317                 else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
 318                         result = options->walk(&lookup_blob(entry.oid->hash)->object, OBJ_BLOB, data, options);
 319                 else {
 320                         result = error("in tree %s: entry %s has bad mode %.6o",
 321                                         oid_to_hex(&tree->object.oid), entry.path, entry.mode);
 322                 }
 323                 if (result < 0)
 324                         return result;
 325                 if (!res)
 326                         res = result;
 327         }
 328         return res;
 329 }
 330
 331 static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_options *options)
 332 {
 333         struct commit_list *parents;
 334         int res;
 335         int result;
 336
 337         if (parse_commit(commit))
 338                 return -1;
 339
 340         result = options->walk((struct object *)commit->tree, OBJ_TREE, data, options);
 341         if (result < 0)
 342                 return result;
 343         res = result;
 344
 345         parents = commit->parents;
 346         while (parents) {
 347                 result = options->walk((struct object *)parents->item, OBJ_COMMIT, data, options);
 348                 if (result < 0)
 349                         return result;
 350                 if (!res)
 351                         res = result;
 352                 parents = parents->next;
 353         }
 354         return res;
 355 }
 356
 357 static int fsck_walk_tag(struct tag *tag, void *data, struct fsck_options *options)
 358 {
 359         if (parse_tag(tag))
 360                 return -1;
 361         return options->walk(tag->tagged, OBJ_ANY, data, options);
 362 }
 363
 364 int fsck_walk(struct object *obj, void *data, struct fsck_options *options)
 365 {
 366         if (!obj)
 367                 return -1;
 368         switch (obj->type) {
 369         case OBJ_BLOB:
 370                 return 0;
 371         case OBJ_TREE:
 372                 return fsck_walk_tree((struct tree *)obj, data, options);
 373         case OBJ_COMMIT:
 374                 return fsck_walk_commit((struct commit *)obj, data, options);
 375         case OBJ_TAG:
 376                 return fsck_walk_tag((struct tag *)obj, data, options);
 377         default:
 378                 error("Unknown object type for %s", oid_to_hex(&obj->oid));
 379                 return -1;
 380         }
 381 }
 382
 383 /*
 384  * The entries in a tree are ordered in the _path_ order,
 385  * which means that a directory entry is ordered by adding
 386  * a slash to the end of it.
 387  *
 388  * So a directory called "a" is ordered _after_ a file
 389  * called "a.c", because "a/" sorts after "a.c".
 390  */
 391 #define TREE_UNORDERED (-1)
 392 #define TREE_HAS_DUPS  (-2)
 393
 394 static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 395 {
 396         int len1 = strlen(name1);
 397         int len2 = strlen(name2);
 398         int len = len1 < len2 ? len1 : len2;
 399         unsigned char c1, c2;
 400         int cmp;
 401
 402         cmp = memcmp(name1, name2, len);
 403         if (cmp < 0)
 404                 return 0;
 405         if (cmp > 0)
 406                 return TREE_UNORDERED;
 407
 408         /*
 409          * Ok, the first <len> characters are the same.
 410          * Now we need to order the next one, but turn
 411          * a '\0' into a '/' for a directory entry.
 412          */
 413         c1 = name1[len];
 414         c2 = name2[len];
 415         if (!c1 && !c2)
 416                 /*
 417                  * git-write-tree used to write out a nonsense tree that has
 418                  * entries with the same name, one blob and one tree.  Make
 419                  * sure we do not have duplicate entries.
 420                  */
 421                 return TREE_HAS_DUPS;
 422         if (!c1 && S_ISDIR(mode1))
 423                 c1 = '/';
 424         if (!c2 && S_ISDIR(mode2))
 425                 c2 = '/';
 426         return c1 < c2 ? 0 : TREE_UNORDERED;
 427 }
 428
 429 static int fsck_tree(struct tree *item, struct fsck_options *options)
 430 {
 431         int retval;
 432         int has_null_sha1 = 0;
 433         int has_full_path = 0;
 434         int has_empty_name = 0;
 435         int has_dot = 0;
 436         int has_dotdot = 0;
 437         int has_dotgit = 0;
 438         int has_zero_pad = 0;
 439         int has_bad_modes = 0;
 440         int has_dup_entries = 0;
 441         int not_properly_sorted = 0;
 442         struct tree_desc desc;
 443         unsigned o_mode;
 444         const char *o_name;
 445
 446         init_tree_desc(&desc, item->buffer, item->size);
 447
 448         o_mode = 0;
 449         o_name = NULL;
 450
 451         while (desc.size) {
 452                 unsigned mode;
 453                 const char *name;
 454                 const struct object_id *oid;
 455
 456                 oid = tree_entry_extract(&desc, &name, &mode);
 457
 458                 has_null_sha1 |= is_null_oid(oid);
 459                 has_full_path |= !!strchr(name, '/');
 460                 has_empty_name |= !*name;
 461                 has_dot |= !strcmp(name, ".");
 462                 has_dotdot |= !strcmp(name, "..");
 463                 has_dotgit |= (!strcmp(name, ".git") ||
 464                                is_hfs_dotgit(name) ||
 465                                is_ntfs_dotgit(name));
 466                 has_zero_pad |= *(char *)desc.buffer == '0';
 467                 update_tree_entry(&desc);
 468
 469                 switch (mode) {
 470                 /*
 471                  * Standard modes..
 472                  */
 473                 case S_IFREG | 0755:
 474                 case S_IFREG | 0644:
 475                 case S_IFLNK:
 476                 case S_IFDIR:
 477                 case S_IFGITLINK:
 478                         break;
 479                 /*
 480                  * This is nonstandard, but we had a few of these
 481                  * early on when we honored the full set of mode
 482                  * bits..
 483                  */
 484                 case S_IFREG | 0664:
 485                         if (!options->strict)
 486                                 break;
 487                 default:
 488                         has_bad_modes = 1;
 489                 }
 490
 491                 if (o_name) {
 492                         switch (verify_ordered(o_mode, o_name, mode, name)) {
 493                         case TREE_UNORDERED:
 494                                 not_properly_sorted = 1;
 495                                 break;
 496                         case TREE_HAS_DUPS:
 497                                 has_dup_entries = 1;
 498                                 break;
 499                         default:
 500                                 break;
 501                         }
 502                 }
 503
 504                 o_mode = mode;
 505                 o_name = name;
 506         }
 507
 508         retval = 0;
 509         if (has_null_sha1)
 510                 retval += report(options, &item->object, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
 511         if (has_full_path)
 512                 retval += report(options, &item->object, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
 513         if (has_empty_name)
 514                 retval += report(options, &item->object, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
 515         if (has_dot)
 516                 retval += report(options, &item->object, FSCK_MSG_HAS_DOT, "contains '.'");
 517         if (has_dotdot)
 518                 retval += report(options, &item->object, FSCK_MSG_HAS_DOTDOT, "contains '..'");
 519         if (has_dotgit)
 520                 retval += report(options, &item->object, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
 521         if (has_zero_pad)
 522                 retval += report(options, &item->object, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
 523         if (has_bad_modes)
 524                 retval += report(options, &item->object, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
 525         if (has_dup_entries)
 526                 retval += report(options, &item->object, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
 527         if (not_properly_sorted)
 528                 retval += report(options, &item->object, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
 529         return retval;
 530 }
 531
 532 static int verify_headers(const void *data, unsigned long size,
 533                           struct object *obj, struct fsck_options *options)
 534 {
 535         const char *buffer = (const char *)data;
 536         unsigned long i;
 537
 538         for (i = 0; i < size; i++) {
 539                 switch (buffer[i]) {
 540                 case '\0':
 541                         return report(options, obj,
 542                                 FSCK_MSG_NUL_IN_HEADER,
 543                                 "unterminated header: NUL at offset %ld", i);
 544                 case '\n':
 545                         if (i + 1 < size && buffer[i + 1] == '\n')
 546                                 return 0;
 547                 }
 548         }
 549
 550         /*
 551          * We did not find double-LF that separates the header
 552          * and the body.  Not having a body is not a crime but
 553          * we do want to see the terminating LF for the last header
 554          * line.
 555          */
 556         if (size && buffer[size - 1] == '\n')
 557                 return 0;
 558
 559         return report(options, obj,
 560                 FSCK_MSG_UNTERMINATED_HEADER, "unterminated header");
 561 }
 562
 563 static int fsck_ident(const char **ident, struct object *obj, struct fsck_options *options)
 564 {
 565         const char *p = *ident;
 566         char *end;
 567
 568         *ident = strchrnul(*ident, '\n');
 569         if (**ident == '\n')
 570                 (*ident)++;
 571
 572         if (*p == '<')
 573                 return report(options, obj, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 574         p += strcspn(p, "<>\n");
 575         if (*p == '>')
 576                 return report(options, obj, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
 577         if (*p != '<')
 578                 return report(options, obj, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
 579         if (p[-1] != ' ')
 580                 return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 581         p++;
 582         p += strcspn(p, "<>\n");
 583         if (*p != '>')
 584                 return report(options, obj, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
 585         p++;
 586         if (*p != ' ')
 587                 return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
 588         p++;
 589         if (*p == '0' && p[1] != ' ')
 590                 return report(options, obj, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
 591         if (date_overflows(strtoul(p, &end, 10)))
 592                 return report(options, obj, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
 593         if ((end == p || *end != ' '))
 594                 return report(options, obj, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
 595         p = end + 1;
 596         if ((*p != '+' && *p != '-') ||
 597             !isdigit(p[1]) ||
 598             !isdigit(p[2]) ||
 599             !isdigit(p[3]) ||
 600             !isdigit(p[4]) ||
 601             (p[5] != '\n'))
 602                 return report(options, obj, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
 603         p += 6;
 604         return 0;
 605 }
 606
 607 static int fsck_commit_buffer(struct commit *commit, const char *buffer,
 608         unsigned long size, struct fsck_options *options)
 609 {
 610         unsigned char tree_sha1[20], sha1[20];
 611         struct commit_graft *graft;
 612         unsigned parent_count, parent_line_count = 0, author_count;
 613         int err;
 614         const char *buffer_begin = buffer;
 615
 616         if (verify_headers(buffer, size, &commit->object, options))
 617                 return -1;
 618
 619         if (!skip_prefix(buffer, "tree ", &buffer))
 620                 return report(options, &commit->object, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
 621         if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n') {
 622                 err = report(options, &commit->object, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
 623                 if (err)
 624                         return err;
 625         }
 626         buffer += 41;
 627         while (skip_prefix(buffer, "parent ", &buffer)) {
 628                 if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
 629                         err = report(options, &commit->object, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
 630                         if (err)
 631                                 return err;
 632                 }
 633                 buffer += 41;
 634                 parent_line_count++;
 635         }
 636         graft = lookup_commit_graft(commit->object.oid.hash);
 637         parent_count = commit_list_count(commit->parents);
 638         if (graft) {
 639                 if (graft->nr_parent == -1 && !parent_count)
 640                         ; /* shallow commit */
 641                 else if (graft->nr_parent != parent_count) {
 642                         err = report(options, &commit->object, FSCK_MSG_MISSING_GRAFT, "graft objects missing");
 643                         if (err)
 644                                 return err;
 645                 }
 646         } else {
 647                 if (parent_count != parent_line_count) {
 648                         err = report(options, &commit->object, FSCK_MSG_MISSING_PARENT, "parent objects missing");
 649                         if (err)
 650                                 return err;
 651                 }
 652         }
 653         author_count = 0;
 654         while (skip_prefix(buffer, "author ", &buffer)) {
 655                 author_count++;
 656                 err = fsck_ident(&buffer, &commit->object, options);
 657                 if (err)
 658                         return err;
 659         }
 660         if (author_count < 1)
 661                 err = report(options, &commit->object, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
 662         else if (author_count > 1)
 663                 err = report(options, &commit->object, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
 664         if (err)
 665                 return err;
 666         if (!skip_prefix(buffer, "committer ", &buffer))
 667                 return report(options, &commit->object, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
 668         err = fsck_ident(&buffer, &commit->object, options);
 669         if (err)
 670                 return err;
 671         if (!commit->tree) {
 672                 err = report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
 673                 if (err)
 674                         return err;
 675         }
 676         if (memchr(buffer_begin, '\0', size)) {
 677                 err = report(options, &commit->object, FSCK_MSG_NUL_IN_COMMIT,
 678                              "NUL byte in the commit object body");
 679                 if (err)
 680                         return err;
 681         }
 682         return 0;
 683 }
 684
 685 static int fsck_commit(struct commit *commit, const char *data,
 686         unsigned long size, struct fsck_options *options)
 687 {
 688         const char *buffer = data ?  data : get_commit_buffer(commit, &size);
 689         int ret = fsck_commit_buffer(commit, buffer, size, options);
 690         if (!data)
 691                 unuse_commit_buffer(commit, buffer);
 692         return ret;
 693 }
 694
 695 static int fsck_tag_buffer(struct tag *tag, const char *data,
 696         unsigned long size, struct fsck_options *options)
 697 {
 698         unsigned char sha1[20];
 699         int ret = 0;
 700         const char *buffer;
 701         char *to_free = NULL, *eol;
 702         struct strbuf sb = STRBUF_INIT;
 703
 704         if (data)
 705                 buffer = data;
 706         else {
 707                 enum object_type type;
 708
 709                 buffer = to_free =
 710                         read_sha1_file(tag->object.oid.hash, &type, &size);
 711                 if (!buffer)
 712                         return report(options, &tag->object,
 713                                 FSCK_MSG_MISSING_TAG_OBJECT,
 714                                 "cannot read tag object");
 715
 716                 if (type != OBJ_TAG) {
 717                         ret = report(options, &tag->object,
 718                                 FSCK_MSG_TAG_OBJECT_NOT_TAG,
 719                                 "expected tag got %s",
 720                             typename(type));
 721                         goto done;
 722                 }
 723         }
 724
 725         ret = verify_headers(buffer, size, &tag->object, options);
 726         if (ret)
 727                 goto done;
 728
 729         if (!skip_prefix(buffer, "object ", &buffer)) {
 730                 ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 731                 goto done;
 732         }
 733         if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
 734                 ret = report(options, &tag->object, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
 735                 if (ret)
 736                         goto done;
 737         }
 738         buffer += 41;
 739
 740         if (!skip_prefix(buffer, "type ", &buffer)) {
 741                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
 742                 goto done;
 743         }
 744         eol = strchr(buffer, '\n');
 745         if (!eol) {
 746                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
 747                 goto done;
 748         }
 749         if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
 750                 ret = report(options, &tag->object, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
 751         if (ret)
 752                 goto done;
 753         buffer = eol + 1;
 754
 755         if (!skip_prefix(buffer, "tag ", &buffer)) {
 756                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
 757                 goto done;
 758         }
 759         eol = strchr(buffer, '\n');
 760         if (!eol) {
 761                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
 762                 goto done;
 763         }
 764         strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
 765         if (check_refname_format(sb.buf, 0)) {
 766                 ret = report(options, &tag->object, FSCK_MSG_BAD_TAG_NAME,
 767                            "invalid 'tag' name: %.*s",
 768                            (int)(eol - buffer), buffer);
 769                 if (ret)
 770                         goto done;
 771         }
 772         buffer = eol + 1;
 773
 774         if (!skip_prefix(buffer, "tagger ", &buffer)) {
 775                 /* early tags do not contain 'tagger' lines; warn only */
 776                 ret = report(options, &tag->object, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
 777                 if (ret)
 778                         goto done;
 779         }
 780         else
 781                 ret = fsck_ident(&buffer, &tag->object, options);
 782
 783 done:
 784         strbuf_release(&sb);
 785         free(to_free);
 786         return ret;
 787 }
 788
 789 static int fsck_tag(struct tag *tag, const char *data,
 790         unsigned long size, struct fsck_options *options)
 791 {
 792         struct object *tagged = tag->tagged;
 793
 794         if (!tagged)
 795                 return report(options, &tag->object, FSCK_MSG_BAD_TAG_OBJECT, "could not load tagged object");
 796
 797         return fsck_tag_buffer(tag, data, size, options);
 798 }
 799
 800 int fsck_object(struct object *obj, void *data, unsigned long size,
 801         struct fsck_options *options)
 802 {
 803         if (!obj)
 804                 return report(options, obj, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
 805
 806         if (obj->type == OBJ_BLOB)
 807                 return 0;
 808         if (obj->type == OBJ_TREE)
 809                 return fsck_tree((struct tree *) obj, options);
 810         if (obj->type == OBJ_COMMIT)
 811                 return fsck_commit((struct commit *) obj, (const char *) data,
 812                         size, options);
 813         if (obj->type == OBJ_TAG)
 814                 return fsck_tag((struct tag *) obj, (const char *) data,
 815                         size, options);
 816
 817         return report(options, obj, FSCK_MSG_UNKNOWN_TYPE, "unknown type '%d' (internal fsck error)",
 818                           obj->type);
 819 }
 820
 821 int fsck_error_function(struct object *obj, int msg_type, const char *message)
 822 {
 823         if (msg_type == FSCK_WARN) {
 824                 warning("object %s: %s", oid_to_hex(&obj->oid), message);
 825                 return 0;
 826         }
 827         error("object %s: %s", oid_to_hex(&obj->oid), message);
 828         return 1;
 829 }