Andrew's git / gitweb.git / fsck.c
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fsck.con commit Merge branch 'po/everyday-doc' (1cb3324)
   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
  11static int fsck_walk_tree(struct tree *tree, fsck_walk_func walk, void *data)
  12{
  13        struct tree_desc desc;
  14        struct name_entry entry;
  15        int res = 0;
  16
  17        if (parse_tree(tree))
  18                return -1;
  19
  20        init_tree_desc(&desc, tree->buffer, tree->size);
  21        while (tree_entry(&desc, &entry)) {
  22                int result;
  23
  24                if (S_ISGITLINK(entry.mode))
  25                        continue;
  26                if (S_ISDIR(entry.mode))
  27                        result = walk(&lookup_tree(entry.sha1)->object, OBJ_TREE, data);
  28                else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
  29                        result = walk(&lookup_blob(entry.sha1)->object, OBJ_BLOB, data);
  30                else {
  31                        result = error("in tree %s: entry %s has bad mode %.6o",
  32                                        sha1_to_hex(tree->object.sha1), entry.path, entry.mode);
  33                }
  34                if (result < 0)
  35                        return result;
  36                if (!res)
  37                        res = result;
  38        }
  39        return res;
  40}
  41
  42static int fsck_walk_commit(struct commit *commit, fsck_walk_func walk, void *data)
  43{
  44        struct commit_list *parents;
  45        int res;
  46        int result;
  47
  48        if (parse_commit(commit))
  49                return -1;
  50
  51        result = walk((struct object *)commit->tree, OBJ_TREE, data);
  52        if (result < 0)
  53                return result;
  54        res = result;
  55
  56        parents = commit->parents;
  57        while (parents) {
  58                result = walk((struct object *)parents->item, OBJ_COMMIT, data);
  59                if (result < 0)
  60                        return result;
  61                if (!res)
  62                        res = result;
  63                parents = parents->next;
  64        }
  65        return res;
  66}
  67
  68static int fsck_walk_tag(struct tag *tag, fsck_walk_func walk, void *data)
  69{
  70        if (parse_tag(tag))
  71                return -1;
  72        return walk(tag->tagged, OBJ_ANY, data);
  73}
  74
  75int fsck_walk(struct object *obj, fsck_walk_func walk, void *data)
  76{
  77        if (!obj)
  78                return -1;
  79        switch (obj->type) {
  80        case OBJ_BLOB:
  81                return 0;
  82        case OBJ_TREE:
  83                return fsck_walk_tree((struct tree *)obj, walk, data);
  84        case OBJ_COMMIT:
  85                return fsck_walk_commit((struct commit *)obj, walk, data);
  86        case OBJ_TAG:
  87                return fsck_walk_tag((struct tag *)obj, walk, data);
  88        default:
  89                error("Unknown object type for %s", sha1_to_hex(obj->sha1));
  90                return -1;
  91        }
  92}
  93
  94/*
  95 * The entries in a tree are ordered in the _path_ order,
  96 * which means that a directory entry is ordered by adding
  97 * a slash to the end of it.
  98 *
  99 * So a directory called "a" is ordered _after_ a file
 100 * called "a.c", because "a/" sorts after "a.c".
 101 */
 102#define TREE_UNORDERED (-1)
 103#define TREE_HAS_DUPS  (-2)
 104
 105static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, const char *name2)
 106{
 107        int len1 = strlen(name1);
 108        int len2 = strlen(name2);
 109        int len = len1 < len2 ? len1 : len2;
 110        unsigned char c1, c2;
 111        int cmp;
 112
 113        cmp = memcmp(name1, name2, len);
 114        if (cmp < 0)
 115                return 0;
 116        if (cmp > 0)
 117                return TREE_UNORDERED;
 118
 119        /*
 120         * Ok, the first <len> characters are the same.
 121         * Now we need to order the next one, but turn
 122         * a '\0' into a '/' for a directory entry.
 123         */
 124        c1 = name1[len];
 125        c2 = name2[len];
 126        if (!c1 && !c2)
 127                /*
 128                 * git-write-tree used to write out a nonsense tree that has
 129                 * entries with the same name, one blob and one tree.  Make
 130                 * sure we do not have duplicate entries.
 131                 */
 132                return TREE_HAS_DUPS;
 133        if (!c1 && S_ISDIR(mode1))
 134                c1 = '/';
 135        if (!c2 && S_ISDIR(mode2))
 136                c2 = '/';
 137        return c1 < c2 ? 0 : TREE_UNORDERED;
 138}
 139
 140static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
 141{
 142        int retval;
 143        int has_null_sha1 = 0;
 144        int has_full_path = 0;
 145        int has_empty_name = 0;
 146        int has_dot = 0;
 147        int has_dotdot = 0;
 148        int has_dotgit = 0;
 149        int has_zero_pad = 0;
 150        int has_bad_modes = 0;
 151        int has_dup_entries = 0;
 152        int not_properly_sorted = 0;
 153        struct tree_desc desc;
 154        unsigned o_mode;
 155        const char *o_name;
 156
 157        init_tree_desc(&desc, item->buffer, item->size);
 158
 159        o_mode = 0;
 160        o_name = NULL;
 161
 162        while (desc.size) {
 163                unsigned mode;
 164                const char *name;
 165                const unsigned char *sha1;
 166
 167                sha1 = tree_entry_extract(&desc, &name, &mode);
 168
 169                has_null_sha1 |= is_null_sha1(sha1);
 170                has_full_path |= !!strchr(name, '/');
 171                has_empty_name |= !*name;
 172                has_dot |= !strcmp(name, ".");
 173                has_dotdot |= !strcmp(name, "..");
 174                has_dotgit |= !strcmp(name, ".git");
 175                has_zero_pad |= *(char *)desc.buffer == '0';
 176                update_tree_entry(&desc);
 177
 178                switch (mode) {
 179                /*
 180                 * Standard modes..
 181                 */
 182                case S_IFREG | 0755:
 183                case S_IFREG | 0644:
 184                case S_IFLNK:
 185                case S_IFDIR:
 186                case S_IFGITLINK:
 187                        break;
 188                /*
 189                 * This is nonstandard, but we had a few of these
 190                 * early on when we honored the full set of mode
 191                 * bits..
 192                 */
 193                case S_IFREG | 0664:
 194                        if (!strict)
 195                                break;
 196                default:
 197                        has_bad_modes = 1;
 198                }
 199
 200                if (o_name) {
 201                        switch (verify_ordered(o_mode, o_name, mode, name)) {
 202                        case TREE_UNORDERED:
 203                                not_properly_sorted = 1;
 204                                break;
 205                        case TREE_HAS_DUPS:
 206                                has_dup_entries = 1;
 207                                break;
 208                        default:
 209                                break;
 210                        }
 211                }
 212
 213                o_mode = mode;
 214                o_name = name;
 215        }
 216
 217        retval = 0;
 218        if (has_null_sha1)
 219                retval += error_func(&item->object, FSCK_WARN, "contains entries pointing to null sha1");
 220        if (has_full_path)
 221                retval += error_func(&item->object, FSCK_WARN, "contains full pathnames");
 222        if (has_empty_name)
 223                retval += error_func(&item->object, FSCK_WARN, "contains empty pathname");
 224        if (has_dot)
 225                retval += error_func(&item->object, FSCK_WARN, "contains '.'");
 226        if (has_dotdot)
 227                retval += error_func(&item->object, FSCK_WARN, "contains '..'");
 228        if (has_dotgit)
 229                retval += error_func(&item->object, FSCK_WARN, "contains '.git'");
 230        if (has_zero_pad)
 231                retval += error_func(&item->object, FSCK_WARN, "contains zero-padded file modes");
 232        if (has_bad_modes)
 233                retval += error_func(&item->object, FSCK_WARN, "contains bad file modes");
 234        if (has_dup_entries)
 235                retval += error_func(&item->object, FSCK_ERROR, "contains duplicate file entries");
 236        if (not_properly_sorted)
 237                retval += error_func(&item->object, FSCK_ERROR, "not properly sorted");
 238        return retval;
 239}
 240
 241static int require_end_of_header(const void *data, unsigned long size,
 242        struct object *obj, fsck_error error_func)
 243{
 244        const char *buffer = (const char *)data;
 245        unsigned long i;
 246
 247        for (i = 0; i < size; i++) {
 248                switch (buffer[i]) {
 249                case '\0':
 250                        return error_func(obj, FSCK_ERROR,
 251                                "unterminated header: NUL at offset %d", i);
 252                case '\n':
 253                        if (i + 1 < size && buffer[i + 1] == '\n')
 254                                return 0;
 255                }
 256        }
 257
 258        return error_func(obj, FSCK_ERROR, "unterminated header");
 259}
 260
 261static int fsck_ident(const char **ident, struct object *obj, fsck_error error_func)
 262{
 263        char *end;
 264
 265        if (**ident == '<')
 266                return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before email");
 267        *ident += strcspn(*ident, "<>\n");
 268        if (**ident == '>')
 269                return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad name");
 270        if (**ident != '<')
 271                return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing email");
 272        if ((*ident)[-1] != ' ')
 273                return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before email");
 274        (*ident)++;
 275        *ident += strcspn(*ident, "<>\n");
 276        if (**ident != '>')
 277                return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad email");
 278        (*ident)++;
 279        if (**ident != ' ')
 280                return error_func(obj, FSCK_ERROR, "invalid author/committer line - missing space before date");
 281        (*ident)++;
 282        if (**ident == '0' && (*ident)[1] != ' ')
 283                return error_func(obj, FSCK_ERROR, "invalid author/committer line - zero-padded date");
 284        if (date_overflows(strtoul(*ident, &end, 10)))
 285                return error_func(obj, FSCK_ERROR, "invalid author/committer line - date causes integer overflow");
 286        if (end == *ident || *end != ' ')
 287                return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad date");
 288        *ident = end + 1;
 289        if ((**ident != '+' && **ident != '-') ||
 290            !isdigit((*ident)[1]) ||
 291            !isdigit((*ident)[2]) ||
 292            !isdigit((*ident)[3]) ||
 293            !isdigit((*ident)[4]) ||
 294            ((*ident)[5] != '\n'))
 295                return error_func(obj, FSCK_ERROR, "invalid author/committer line - bad time zone");
 296        (*ident) += 6;
 297        return 0;
 298}
 299
 300static int fsck_commit_buffer(struct commit *commit, const char *buffer,
 301        unsigned long size, fsck_error error_func)
 302{
 303        unsigned char tree_sha1[20], sha1[20];
 304        struct commit_graft *graft;
 305        unsigned parent_count, parent_line_count = 0;
 306        int err;
 307
 308        if (require_end_of_header(buffer, size, &commit->object, error_func))
 309                return -1;
 310
 311        if (!skip_prefix(buffer, "tree ", &buffer))
 312                return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'tree' line");
 313        if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n')
 314                return error_func(&commit->object, FSCK_ERROR, "invalid 'tree' line format - bad sha1");
 315        buffer += 41;
 316        while (skip_prefix(buffer, "parent ", &buffer)) {
 317                if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
 318                        return error_func(&commit->object, FSCK_ERROR, "invalid 'parent' line format - bad sha1");
 319                buffer += 41;
 320                parent_line_count++;
 321        }
 322        graft = lookup_commit_graft(commit->object.sha1);
 323        parent_count = commit_list_count(commit->parents);
 324        if (graft) {
 325                if (graft->nr_parent == -1 && !parent_count)
 326                        ; /* shallow commit */
 327                else if (graft->nr_parent != parent_count)
 328                        return error_func(&commit->object, FSCK_ERROR, "graft objects missing");
 329        } else {
 330                if (parent_count != parent_line_count)
 331                        return error_func(&commit->object, FSCK_ERROR, "parent objects missing");
 332        }
 333        if (!skip_prefix(buffer, "author ", &buffer))
 334                return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'author' line");
 335        err = fsck_ident(&buffer, &commit->object, error_func);
 336        if (err)
 337                return err;
 338        if (!skip_prefix(buffer, "committer ", &buffer))
 339                return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'committer' line");
 340        err = fsck_ident(&buffer, &commit->object, error_func);
 341        if (err)
 342                return err;
 343        if (!commit->tree)
 344                return error_func(&commit->object, FSCK_ERROR, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
 345
 346        return 0;
 347}
 348
 349static int fsck_commit(struct commit *commit, const char *data,
 350        unsigned long size, fsck_error error_func)
 351{
 352        const char *buffer = data ?  data : get_commit_buffer(commit, &size);
 353        int ret = fsck_commit_buffer(commit, buffer, size, error_func);
 354        if (!data)
 355                unuse_commit_buffer(commit, buffer);
 356        return ret;
 357}
 358
 359static int fsck_tag_buffer(struct tag *tag, const char *data,
 360        unsigned long size, fsck_error error_func)
 361{
 362        unsigned char sha1[20];
 363        int ret = 0;
 364        const char *buffer;
 365        char *to_free = NULL, *eol;
 366        struct strbuf sb = STRBUF_INIT;
 367
 368        if (data)
 369                buffer = data;
 370        else {
 371                enum object_type type;
 372
 373                buffer = to_free =
 374                        read_sha1_file(tag->object.sha1, &type, &size);
 375                if (!buffer)
 376                        return error_func(&tag->object, FSCK_ERROR,
 377                                "cannot read tag object");
 378
 379                if (type != OBJ_TAG) {
 380                        ret = error_func(&tag->object, FSCK_ERROR,
 381                                "expected tag got %s",
 382                            typename(type));
 383                        goto done;
 384                }
 385        }
 386
 387        if (require_end_of_header(buffer, size, &tag->object, error_func))
 388                goto done;
 389
 390        if (!skip_prefix(buffer, "object ", &buffer)) {
 391                ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'object' line");
 392                goto done;
 393        }
 394        if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
 395                ret = error_func(&tag->object, FSCK_ERROR, "invalid 'object' line format - bad sha1");
 396                goto done;
 397        }
 398        buffer += 41;
 399
 400        if (!skip_prefix(buffer, "type ", &buffer)) {
 401                ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'type' line");
 402                goto done;
 403        }
 404        eol = strchr(buffer, '\n');
 405        if (!eol) {
 406                ret = error_func(&tag->object, FSCK_ERROR, "invalid format - unexpected end after 'type' line");
 407                goto done;
 408        }
 409        if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
 410                ret = error_func(&tag->object, FSCK_ERROR, "invalid 'type' value");
 411        if (ret)
 412                goto done;
 413        buffer = eol + 1;
 414
 415        if (!skip_prefix(buffer, "tag ", &buffer)) {
 416                ret = error_func(&tag->object, FSCK_ERROR, "invalid format - expected 'tag' line");
 417                goto done;
 418        }
 419        eol = strchr(buffer, '\n');
 420        if (!eol) {
 421                ret = error_func(&tag->object, FSCK_ERROR, "invalid format - unexpected end after 'type' line");
 422                goto done;
 423        }
 424        strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
 425        if (check_refname_format(sb.buf, 0))
 426                error_func(&tag->object, FSCK_WARN, "invalid 'tag' name: %s", buffer);
 427        buffer = eol + 1;
 428
 429        if (!skip_prefix(buffer, "tagger ", &buffer))
 430                /* early tags do not contain 'tagger' lines; warn only */
 431                error_func(&tag->object, FSCK_WARN, "invalid format - expected 'tagger' line");
 432        else
 433                ret = fsck_ident(&buffer, &tag->object, error_func);
 434
 435done:
 436        strbuf_release(&sb);
 437        free(to_free);
 438        return ret;
 439}
 440
 441static int fsck_tag(struct tag *tag, const char *data,
 442        unsigned long size, fsck_error error_func)
 443{
 444        struct object *tagged = tag->tagged;
 445
 446        if (!tagged)
 447                return error_func(&tag->object, FSCK_ERROR, "could not load tagged object");
 448
 449        return fsck_tag_buffer(tag, data, size, error_func);
 450}
 451
 452int fsck_object(struct object *obj, void *data, unsigned long size,
 453        int strict, fsck_error error_func)
 454{
 455        if (!obj)
 456                return error_func(obj, FSCK_ERROR, "no valid object to fsck");
 457
 458        if (obj->type == OBJ_BLOB)
 459                return 0;
 460        if (obj->type == OBJ_TREE)
 461                return fsck_tree((struct tree *) obj, strict, error_func);
 462        if (obj->type == OBJ_COMMIT)
 463                return fsck_commit((struct commit *) obj, (const char *) data,
 464                        size, error_func);
 465        if (obj->type == OBJ_TAG)
 466                return fsck_tag((struct tag *) obj, (const char *) data,
 467                        size, error_func);
 468
 469        return error_func(obj, FSCK_ERROR, "unknown type '%d' (internal fsck error)",
 470                          obj->type);
 471}
 472
 473int fsck_error_function(struct object *obj, int type, const char *fmt, ...)
 474{
 475        va_list ap;
 476        struct strbuf sb = STRBUF_INIT;
 477
 478        strbuf_addf(&sb, "object %s:", sha1_to_hex(obj->sha1));
 479
 480        va_start(ap, fmt);
 481        strbuf_vaddf(&sb, fmt, ap);
 482        va_end(ap);
 483
 484        error("%s", sb.buf);
 485        strbuf_release(&sb);
 486        return 1;
 487}