Andrew's git / gitweb.git / fsck.c
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fsck.con commit clone: better error when --reference is a linked checkout (d78db84)
   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,
  67enum 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 },
  75static 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
  85static 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
 113static 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
 131static 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
 168static 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
 180int 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
 188void 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
 211void 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
 249static 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)))
 268static 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->sha1) >= 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
 298static 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                                        sha1_to_hex(tree->object.sha1), entry.path, entry.mode);
 320                }
 321                if (result < 0)
 322                        return result;
 323                if (!res)
 324                        res = result;
 325        }
 326        return res;
 327}
 328
 329static 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
 355static 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
 362int 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", sha1_to_hex(obj->sha1));
 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
 392static 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
 427static 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
 530static 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
 561static 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
 605static 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.sha1);
 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
 674static 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
 684static 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.sha1, &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        if (verify_headers(buffer, size, &tag->object, options))
 715                goto done;
 716
 717        if (!skip_prefix(buffer, "object ", &buffer)) {
 718                ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 719                goto done;
 720        }
 721        if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
 722                ret = report(options, &tag->object, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
 723                if (ret)
 724                        goto done;
 725        }
 726        buffer += 41;
 727
 728        if (!skip_prefix(buffer, "type ", &buffer)) {
 729                ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
 730                goto done;
 731        }
 732        eol = strchr(buffer, '\n');
 733        if (!eol) {
 734                ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
 735                goto done;
 736        }
 737        if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
 738                ret = report(options, &tag->object, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
 739        if (ret)
 740                goto done;
 741        buffer = eol + 1;
 742
 743        if (!skip_prefix(buffer, "tag ", &buffer)) {
 744                ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
 745                goto done;
 746        }
 747        eol = strchr(buffer, '\n');
 748        if (!eol) {
 749                ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
 750                goto done;
 751        }
 752        strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
 753        if (check_refname_format(sb.buf, 0)) {
 754                ret = report(options, &tag->object, FSCK_MSG_BAD_TAG_NAME,
 755                           "invalid 'tag' name: %.*s",
 756                           (int)(eol - buffer), buffer);
 757                if (ret)
 758                        goto done;
 759        }
 760        buffer = eol + 1;
 761
 762        if (!skip_prefix(buffer, "tagger ", &buffer)) {
 763                /* early tags do not contain 'tagger' lines; warn only */
 764                ret = report(options, &tag->object, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
 765                if (ret)
 766                        goto done;
 767        }
 768        else
 769                ret = fsck_ident(&buffer, &tag->object, options);
 770
 771done:
 772        strbuf_release(&sb);
 773        free(to_free);
 774        return ret;
 775}
 776
 777static int fsck_tag(struct tag *tag, const char *data,
 778        unsigned long size, struct fsck_options *options)
 779{
 780        struct object *tagged = tag->tagged;
 781
 782        if (!tagged)
 783                return report(options, &tag->object, FSCK_MSG_BAD_TAG_OBJECT, "could not load tagged object");
 784
 785        return fsck_tag_buffer(tag, data, size, options);
 786}
 787
 788int fsck_object(struct object *obj, void *data, unsigned long size,
 789        struct fsck_options *options)
 790{
 791        if (!obj)
 792                return report(options, obj, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
 793
 794        if (obj->type == OBJ_BLOB)
 795                return 0;
 796        if (obj->type == OBJ_TREE)
 797                return fsck_tree((struct tree *) obj, options);
 798        if (obj->type == OBJ_COMMIT)
 799                return fsck_commit((struct commit *) obj, (const char *) data,
 800                        size, options);
 801        if (obj->type == OBJ_TAG)
 802                return fsck_tag((struct tag *) obj, (const char *) data,
 803                        size, options);
 804
 805        return report(options, obj, FSCK_MSG_UNKNOWN_TYPE, "unknown type '%d' (internal fsck error)",
 806                          obj->type);
 807}
 808
 809int fsck_error_function(struct object *obj, int msg_type, const char *message)
 810{
 811        if (msg_type == FSCK_WARN) {
 812                warning("object %s: %s", sha1_to_hex(obj->sha1), message);
 813                return 0;
 814        }
 815        error("object %s: %s", sha1_to_hex(obj->sha1), message);
 816        return 1;
 817}