git.oblomov.eu Git - git/blob - sha1_file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This handles basic git sha1 object files - packing, unpacking,
   7  * creation etc.
   8  */
   9 #include "cache.h"
  10 #include "config.h"
  11 #include "string-list.h"
  12 #include "lockfile.h"
  13 #include "delta.h"
  14 #include "pack.h"
  15 #include "blob.h"
  16 #include "commit.h"
  17 #include "run-command.h"
  18 #include "tag.h"
  19 #include "tree.h"
  20 #include "tree-walk.h"
  21 #include "refs.h"
  22 #include "pack-revindex.h"
  23 #include "sha1-lookup.h"
  24 #include "bulk-checkin.h"
  25 #include "streaming.h"
  26 #include "dir.h"
  27 #include "list.h"
  28 #include "mergesort.h"
  29 #include "quote.h"
  30 #include "packfile.h"
  31 #include "fetch-object.h"
  32
  33 const unsigned char null_sha1[GIT_MAX_RAWSZ];
  34 const struct object_id null_oid;
  35 const struct object_id empty_tree_oid = {
  36         EMPTY_TREE_SHA1_BIN_LITERAL
  37 };
  38 const struct object_id empty_blob_oid = {
  39         EMPTY_BLOB_SHA1_BIN_LITERAL
  40 };
  41
  42 static void git_hash_sha1_init(void *ctx)
  43 {
  44         git_SHA1_Init((git_SHA_CTX *)ctx);
  45 }
  46
  47 static void git_hash_sha1_update(void *ctx, const void *data, size_t len)
  48 {
  49         git_SHA1_Update((git_SHA_CTX *)ctx, data, len);
  50 }
  51
  52 static void git_hash_sha1_final(unsigned char *hash, void *ctx)
  53 {
  54         git_SHA1_Final(hash, (git_SHA_CTX *)ctx);
  55 }
  56
  57 static void git_hash_unknown_init(void *ctx)
  58 {
  59         die("trying to init unknown hash");
  60 }
  61
  62 static void git_hash_unknown_update(void *ctx, const void *data, size_t len)
  63 {
  64         die("trying to update unknown hash");
  65 }
  66
  67 static void git_hash_unknown_final(unsigned char *hash, void *ctx)
  68 {
  69         die("trying to finalize unknown hash");
  70 }
  71
  72 const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
  73         {
  74                 NULL,
  75                 0x00000000,
  76                 0,
  77                 0,
  78                 0,
  79                 git_hash_unknown_init,
  80                 git_hash_unknown_update,
  81                 git_hash_unknown_final,
  82                 NULL,
  83                 NULL,
  84         },
  85         {
  86                 "sha-1",
  87                 /* "sha1", big-endian */
  88                 0x73686131,
  89                 sizeof(git_SHA_CTX),
  90                 GIT_SHA1_RAWSZ,
  91                 GIT_SHA1_HEXSZ,
  92                 git_hash_sha1_init,
  93                 git_hash_sha1_update,
  94                 git_hash_sha1_final,
  95                 &empty_tree_oid,
  96                 &empty_blob_oid,
  97         },
  98 };
  99
 100 /*
 101  * This is meant to hold a *small* number of objects that you would
 102  * want read_sha1_file() to be able to return, but yet you do not want
 103  * to write them into the object store (e.g. a browse-only
 104  * application).
 105  */
 106 static struct cached_object {
 107         unsigned char sha1[20];
 108         enum object_type type;
 109         void *buf;
 110         unsigned long size;
 111 } *cached_objects;
 112 static int cached_object_nr, cached_object_alloc;
 113
 114 static struct cached_object empty_tree = {
 115         EMPTY_TREE_SHA1_BIN_LITERAL,
 116         OBJ_TREE,
 117         "",
 118         0
 119 };
 120
 121 static struct cached_object *find_cached_object(const unsigned char *sha1)
 122 {
 123         int i;
 124         struct cached_object *co = cached_objects;
 125
 126         for (i = 0; i < cached_object_nr; i++, co++) {
 127                 if (!hashcmp(co->sha1, sha1))
 128                         return co;
 129         }
 130         if (!hashcmp(sha1, empty_tree.sha1))
 131                 return &empty_tree;
 132         return NULL;
 133 }
 134
 135
 136 static int get_conv_flags(unsigned flags)
 137 {
 138         if (flags & HASH_RENORMALIZE)
 139                 return CONV_EOL_RENORMALIZE;
 140         else if (flags & HASH_WRITE_OBJECT)
 141           return global_conv_flags_eol;
 142         else
 143                 return 0;
 144 }
 145
 146
 147 int mkdir_in_gitdir(const char *path)
 148 {
 149         if (mkdir(path, 0777)) {
 150                 int saved_errno = errno;
 151                 struct stat st;
 152                 struct strbuf sb = STRBUF_INIT;
 153
 154                 if (errno != EEXIST)
 155                         return -1;
 156                 /*
 157                  * Are we looking at a path in a symlinked worktree
 158                  * whose original repository does not yet have it?
 159                  * e.g. .git/rr-cache pointing at its original
 160                  * repository in which the user hasn't performed any
 161                  * conflict resolution yet?
 162                  */
 163                 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 164                     strbuf_readlink(&sb, path, st.st_size) ||
 165                     !is_absolute_path(sb.buf) ||
 166                     mkdir(sb.buf, 0777)) {
 167                         strbuf_release(&sb);
 168                         errno = saved_errno;
 169                         return -1;
 170                 }
 171                 strbuf_release(&sb);
 172         }
 173         return adjust_shared_perm(path);
 174 }
 175
 176 enum scld_error safe_create_leading_directories(char *path)
 177 {
 178         char *next_component = path + offset_1st_component(path);
 179         enum scld_error ret = SCLD_OK;
 180
 181         while (ret == SCLD_OK && next_component) {
 182                 struct stat st;
 183                 char *slash = next_component, slash_character;
 184
 185                 while (*slash && !is_dir_sep(*slash))
 186                         slash++;
 187
 188                 if (!*slash)
 189                         break;
 190
 191                 next_component = slash + 1;
 192                 while (is_dir_sep(*next_component))
 193                         next_component++;
 194                 if (!*next_component)
 195                         break;
 196
 197                 slash_character = *slash;
 198                 *slash = '\0';
 199                 if (!stat(path, &st)) {
 200                         /* path exists */
 201                         if (!S_ISDIR(st.st_mode)) {
 202                                 errno = ENOTDIR;
 203                                 ret = SCLD_EXISTS;
 204                         }
 205                 } else if (mkdir(path, 0777)) {
 206                         if (errno == EEXIST &&
 207                             !stat(path, &st) && S_ISDIR(st.st_mode))
 208                                 ; /* somebody created it since we checked */
 209                         else if (errno == ENOENT)
 210                                 /*
 211                                  * Either mkdir() failed because
 212                                  * somebody just pruned the containing
 213                                  * directory, or stat() failed because
 214                                  * the file that was in our way was
 215                                  * just removed.  Either way, inform
 216                                  * the caller that it might be worth
 217                                  * trying again:
 218                                  */
 219                                 ret = SCLD_VANISHED;
 220                         else
 221                                 ret = SCLD_FAILED;
 222                 } else if (adjust_shared_perm(path)) {
 223                         ret = SCLD_PERMS;
 224                 }
 225                 *slash = slash_character;
 226         }
 227         return ret;
 228 }
 229
 230 enum scld_error safe_create_leading_directories_const(const char *path)
 231 {
 232         int save_errno;
 233         /* path points to cache entries, so xstrdup before messing with it */
 234         char *buf = xstrdup(path);
 235         enum scld_error result = safe_create_leading_directories(buf);
 236
 237         save_errno = errno;
 238         free(buf);
 239         errno = save_errno;
 240         return result;
 241 }
 242
 243 int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 244 {
 245         /*
 246          * The number of times we will try to remove empty directories
 247          * in the way of path. This is only 1 because if another
 248          * process is racily creating directories that conflict with
 249          * us, we don't want to fight against them.
 250          */
 251         int remove_directories_remaining = 1;
 252
 253         /*
 254          * The number of times that we will try to create the
 255          * directories containing path. We are willing to attempt this
 256          * more than once, because another process could be trying to
 257          * clean up empty directories at the same time as we are
 258          * trying to create them.
 259          */
 260         int create_directories_remaining = 3;
 261
 262         /* A scratch copy of path, filled lazily if we need it: */
 263         struct strbuf path_copy = STRBUF_INIT;
 264
 265         int ret, save_errno;
 266
 267         /* Sanity check: */
 268         assert(*path);
 269
 270 retry_fn:
 271         ret = fn(path, cb);
 272         save_errno = errno;
 273         if (!ret)
 274                 goto out;
 275
 276         if (errno == EISDIR && remove_directories_remaining-- > 0) {
 277                 /*
 278                  * A directory is in the way. Maybe it is empty; try
 279                  * to remove it:
 280                  */
 281                 if (!path_copy.len)
 282                         strbuf_addstr(&path_copy, path);
 283
 284                 if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 285                         goto retry_fn;
 286         } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 287                 /*
 288                  * Maybe the containing directory didn't exist, or
 289                  * maybe it was just deleted by a process that is
 290                  * racing with us to clean up empty directories. Try
 291                  * to create it:
 292                  */
 293                 enum scld_error scld_result;
 294
 295                 if (!path_copy.len)
 296                         strbuf_addstr(&path_copy, path);
 297
 298                 do {
 299                         scld_result = safe_create_leading_directories(path_copy.buf);
 300                         if (scld_result == SCLD_OK)
 301                                 goto retry_fn;
 302                 } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 303         }
 304
 305 out:
 306         strbuf_release(&path_copy);
 307         errno = save_errno;
 308         return ret;
 309 }
 310
 311 static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 312 {
 313         int i;
 314         for (i = 0; i < 20; i++) {
 315                 static char hex[] = "0123456789abcdef";
 316                 unsigned int val = sha1[i];
 317                 strbuf_addch(buf, hex[val >> 4]);
 318                 strbuf_addch(buf, hex[val & 0xf]);
 319                 if (!i)
 320                         strbuf_addch(buf, '/');
 321         }
 322 }
 323
 324 void sha1_file_name(struct strbuf *buf, const unsigned char *sha1)
 325 {
 326         strbuf_addstr(buf, get_object_directory());
 327         strbuf_addch(buf, '/');
 328         fill_sha1_path(buf, sha1);
 329 }
 330
 331 struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 332 {
 333         strbuf_setlen(&alt->scratch, alt->base_len);
 334         return &alt->scratch;
 335 }
 336
 337 static const char *alt_sha1_path(struct alternate_object_database *alt,
 338                                  const unsigned char *sha1)
 339 {
 340         struct strbuf *buf = alt_scratch_buf(alt);
 341         fill_sha1_path(buf, sha1);
 342         return buf->buf;
 343 }
 344
 345 struct alternate_object_database *alt_odb_list;
 346 static struct alternate_object_database **alt_odb_tail;
 347
 348 /*
 349  * Return non-zero iff the path is usable as an alternate object database.
 350  */
 351 static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 352 {
 353         struct alternate_object_database *alt;
 354
 355         /* Detect cases where alternate disappeared */
 356         if (!is_directory(path->buf)) {
 357                 error("object directory %s does not exist; "
 358                       "check .git/objects/info/alternates.",
 359                       path->buf);
 360                 return 0;
 361         }
 362
 363         /*
 364          * Prevent the common mistake of listing the same
 365          * thing twice, or object directory itself.
 366          */
 367         for (alt = alt_odb_list; alt; alt = alt->next) {
 368                 if (!fspathcmp(path->buf, alt->path))
 369                         return 0;
 370         }
 371         if (!fspathcmp(path->buf, normalized_objdir))
 372                 return 0;
 373
 374         return 1;
 375 }
 376
 377 /*
 378  * Prepare alternate object database registry.
 379  *
 380  * The variable alt_odb_list points at the list of struct
 381  * alternate_object_database.  The elements on this list come from
 382  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 383  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 384  * whose contents is similar to that environment variable but can be
 385  * LF separated.  Its base points at a statically allocated buffer that
 386  * contains "/the/directory/corresponding/to/.git/objects/...", while
 387  * its name points just after the slash at the end of ".git/objects/"
 388  * in the example above, and has enough space to hold 40-byte hex
 389  * SHA1, an extra slash for the first level indirection, and the
 390  * terminating NUL.
 391  */
 392 static void read_info_alternates(const char * relative_base, int depth);
 393 static int link_alt_odb_entry(const char *entry, const char *relative_base,
 394         int depth, const char *normalized_objdir)
 395 {
 396         struct alternate_object_database *ent;
 397         struct strbuf pathbuf = STRBUF_INIT;
 398
 399         if (!is_absolute_path(entry) && relative_base) {
 400                 strbuf_realpath(&pathbuf, relative_base, 1);
 401                 strbuf_addch(&pathbuf, '/');
 402         }
 403         strbuf_addstr(&pathbuf, entry);
 404
 405         if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 406                 error("unable to normalize alternate object path: %s",
 407                       pathbuf.buf);
 408                 strbuf_release(&pathbuf);
 409                 return -1;
 410         }
 411
 412         /*
 413          * The trailing slash after the directory name is given by
 414          * this function at the end. Remove duplicates.
 415          */
 416         while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 417                 strbuf_setlen(&pathbuf, pathbuf.len - 1);
 418
 419         if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 420                 strbuf_release(&pathbuf);
 421                 return -1;
 422         }
 423
 424         ent = alloc_alt_odb(pathbuf.buf);
 425
 426         /* add the alternate entry */
 427         *alt_odb_tail = ent;
 428         alt_odb_tail = &(ent->next);
 429         ent->next = NULL;
 430
 431         /* recursively add alternates */
 432         read_info_alternates(pathbuf.buf, depth + 1);
 433
 434         strbuf_release(&pathbuf);
 435         return 0;
 436 }
 437
 438 static const char *parse_alt_odb_entry(const char *string,
 439                                        int sep,
 440                                        struct strbuf *out)
 441 {
 442         const char *end;
 443
 444         strbuf_reset(out);
 445
 446         if (*string == '#') {
 447                 /* comment; consume up to next separator */
 448                 end = strchrnul(string, sep);
 449         } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 450                 /*
 451                  * quoted path; unquote_c_style has copied the
 452                  * data for us and set "end". Broken quoting (e.g.,
 453                  * an entry that doesn't end with a quote) falls
 454                  * back to the unquoted case below.
 455                  */
 456         } else {
 457                 /* normal, unquoted path */
 458                 end = strchrnul(string, sep);
 459                 strbuf_add(out, string, end - string);
 460         }
 461
 462         if (*end)
 463                 end++;
 464         return end;
 465 }
 466
 467 static void link_alt_odb_entries(const char *alt, int sep,
 468                                  const char *relative_base, int depth)
 469 {
 470         struct strbuf objdirbuf = STRBUF_INIT;
 471         struct strbuf entry = STRBUF_INIT;
 472
 473         if (!alt || !*alt)
 474                 return;
 475
 476         if (depth > 5) {
 477                 error("%s: ignoring alternate object stores, nesting too deep.",
 478                                 relative_base);
 479                 return;
 480         }
 481
 482         strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 483         if (strbuf_normalize_path(&objdirbuf) < 0)
 484                 die("unable to normalize object directory: %s",
 485                     objdirbuf.buf);
 486
 487         while (*alt) {
 488                 alt = parse_alt_odb_entry(alt, sep, &entry);
 489                 if (!entry.len)
 490                         continue;
 491                 link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 492         }
 493         strbuf_release(&entry);
 494         strbuf_release(&objdirbuf);
 495 }
 496
 497 static void read_info_alternates(const char * relative_base, int depth)
 498 {
 499         char *path;
 500         struct strbuf buf = STRBUF_INIT;
 501
 502         path = xstrfmt("%s/info/alternates", relative_base);
 503         if (strbuf_read_file(&buf, path, 1024) < 0) {
 504                 warn_on_fopen_errors(path);
 505                 free(path);
 506                 return;
 507         }
 508
 509         link_alt_odb_entries(buf.buf, '\n', relative_base, depth);
 510         strbuf_release(&buf);
 511         free(path);
 512 }
 513
 514 struct alternate_object_database *alloc_alt_odb(const char *dir)
 515 {
 516         struct alternate_object_database *ent;
 517
 518         FLEX_ALLOC_STR(ent, path, dir);
 519         strbuf_init(&ent->scratch, 0);
 520         strbuf_addf(&ent->scratch, "%s/", dir);
 521         ent->base_len = ent->scratch.len;
 522
 523         return ent;
 524 }
 525
 526 void add_to_alternates_file(const char *reference)
 527 {
 528         struct lock_file lock = LOCK_INIT;
 529         char *alts = git_pathdup("objects/info/alternates");
 530         FILE *in, *out;
 531         int found = 0;
 532
 533         hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
 534         out = fdopen_lock_file(&lock, "w");
 535         if (!out)
 536                 die_errno("unable to fdopen alternates lockfile");
 537
 538         in = fopen(alts, "r");
 539         if (in) {
 540                 struct strbuf line = STRBUF_INIT;
 541
 542                 while (strbuf_getline(&line, in) != EOF) {
 543                         if (!strcmp(reference, line.buf)) {
 544                                 found = 1;
 545                                 break;
 546                         }
 547                         fprintf_or_die(out, "%s\n", line.buf);
 548                 }
 549
 550                 strbuf_release(&line);
 551                 fclose(in);
 552         }
 553         else if (errno != ENOENT)
 554                 die_errno("unable to read alternates file");
 555
 556         if (found) {
 557                 rollback_lock_file(&lock);
 558         } else {
 559                 fprintf_or_die(out, "%s\n", reference);
 560                 if (commit_lock_file(&lock))
 561                         die_errno("unable to move new alternates file into place");
 562                 if (alt_odb_tail)
 563                         link_alt_odb_entries(reference, '\n', NULL, 0);
 564         }
 565         free(alts);
 566 }
 567
 568 void add_to_alternates_memory(const char *reference)
 569 {
 570         /*
 571          * Make sure alternates are initialized, or else our entry may be
 572          * overwritten when they are.
 573          */
 574         prepare_alt_odb();
 575
 576         link_alt_odb_entries(reference, '\n', NULL, 0);
 577 }
 578
 579 /*
 580  * Compute the exact path an alternate is at and returns it. In case of
 581  * error NULL is returned and the human readable error is added to `err`
 582  * `path` may be relative and should point to $GITDIR.
 583  * `err` must not be null.
 584  */
 585 char *compute_alternate_path(const char *path, struct strbuf *err)
 586 {
 587         char *ref_git = NULL;
 588         const char *repo, *ref_git_s;
 589         int seen_error = 0;
 590
 591         ref_git_s = real_path_if_valid(path);
 592         if (!ref_git_s) {
 593                 seen_error = 1;
 594                 strbuf_addf(err, _("path '%s' does not exist"), path);
 595                 goto out;
 596         } else
 597                 /*
 598                  * Beware: read_gitfile(), real_path() and mkpath()
 599                  * return static buffer
 600                  */
 601                 ref_git = xstrdup(ref_git_s);
 602
 603         repo = read_gitfile(ref_git);
 604         if (!repo)
 605                 repo = read_gitfile(mkpath("%s/.git", ref_git));
 606         if (repo) {
 607                 free(ref_git);
 608                 ref_git = xstrdup(repo);
 609         }
 610
 611         if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 612                 char *ref_git_git = mkpathdup("%s/.git", ref_git);
 613                 free(ref_git);
 614                 ref_git = ref_git_git;
 615         } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 616                 struct strbuf sb = STRBUF_INIT;
 617                 seen_error = 1;
 618                 if (get_common_dir(&sb, ref_git)) {
 619                         strbuf_addf(err,
 620                                     _("reference repository '%s' as a linked "
 621                                       "checkout is not supported yet."),
 622                                     path);
 623                         goto out;
 624                 }
 625
 626                 strbuf_addf(err, _("reference repository '%s' is not a "
 627                                         "local repository."), path);
 628                 goto out;
 629         }
 630
 631         if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 632                 strbuf_addf(err, _("reference repository '%s' is shallow"),
 633                             path);
 634                 seen_error = 1;
 635                 goto out;
 636         }
 637
 638         if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 639                 strbuf_addf(err,
 640                             _("reference repository '%s' is grafted"),
 641                             path);
 642                 seen_error = 1;
 643                 goto out;
 644         }
 645
 646 out:
 647         if (seen_error) {
 648                 FREE_AND_NULL(ref_git);
 649         }
 650
 651         return ref_git;
 652 }
 653
 654 int foreach_alt_odb(alt_odb_fn fn, void *cb)
 655 {
 656         struct alternate_object_database *ent;
 657         int r = 0;
 658
 659         prepare_alt_odb();
 660         for (ent = alt_odb_list; ent; ent = ent->next) {
 661                 r = fn(ent, cb);
 662                 if (r)
 663                         break;
 664         }
 665         return r;
 666 }
 667
 668 void prepare_alt_odb(void)
 669 {
 670         if (alt_odb_tail)
 671                 return;
 672
 673         alt_odb_tail = &alt_odb_list;
 674         link_alt_odb_entries(the_repository->alternate_db, PATH_SEP, NULL, 0);
 675
 676         read_info_alternates(get_object_directory(), 0);
 677 }
 678
 679 /* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 680 static int freshen_file(const char *fn)
 681 {
 682         struct utimbuf t;
 683         t.actime = t.modtime = time(NULL);
 684         return !utime(fn, &t);
 685 }
 686
 687 /*
 688  * All of the check_and_freshen functions return 1 if the file exists and was
 689  * freshened (if freshening was requested), 0 otherwise. If they return
 690  * 0, you should not assume that it is safe to skip a write of the object (it
 691  * either does not exist on disk, or has a stale mtime and may be subject to
 692  * pruning).
 693  */
 694 int check_and_freshen_file(const char *fn, int freshen)
 695 {
 696         if (access(fn, F_OK))
 697                 return 0;
 698         if (freshen && !freshen_file(fn))
 699                 return 0;
 700         return 1;
 701 }
 702
 703 static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 704 {
 705         static struct strbuf buf = STRBUF_INIT;
 706
 707         strbuf_reset(&buf);
 708         sha1_file_name(&buf, sha1);
 709
 710         return check_and_freshen_file(buf.buf, freshen);
 711 }
 712
 713 static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 714 {
 715         struct alternate_object_database *alt;
 716         prepare_alt_odb();
 717         for (alt = alt_odb_list; alt; alt = alt->next) {
 718                 const char *path = alt_sha1_path(alt, sha1);
 719                 if (check_and_freshen_file(path, freshen))
 720                         return 1;
 721         }
 722         return 0;
 723 }
 724
 725 static int check_and_freshen(const unsigned char *sha1, int freshen)
 726 {
 727         return check_and_freshen_local(sha1, freshen) ||
 728                check_and_freshen_nonlocal(sha1, freshen);
 729 }
 730
 731 int has_loose_object_nonlocal(const unsigned char *sha1)
 732 {
 733         return check_and_freshen_nonlocal(sha1, 0);
 734 }
 735
 736 static int has_loose_object(const unsigned char *sha1)
 737 {
 738         return check_and_freshen(sha1, 0);
 739 }
 740
 741 static void mmap_limit_check(size_t length)
 742 {
 743         static size_t limit = 0;
 744         if (!limit) {
 745                 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 746                 if (!limit)
 747                         limit = SIZE_MAX;
 748         }
 749         if (length > limit)
 750                 die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 751                     (uintmax_t)length, (uintmax_t)limit);
 752 }
 753
 754 void *xmmap_gently(void *start, size_t length,
 755                   int prot, int flags, int fd, off_t offset)
 756 {
 757         void *ret;
 758
 759         mmap_limit_check(length);
 760         ret = mmap(start, length, prot, flags, fd, offset);
 761         if (ret == MAP_FAILED) {
 762                 if (!length)
 763                         return NULL;
 764                 release_pack_memory(length);
 765                 ret = mmap(start, length, prot, flags, fd, offset);
 766         }
 767         return ret;
 768 }
 769
 770 void *xmmap(void *start, size_t length,
 771         int prot, int flags, int fd, off_t offset)
 772 {
 773         void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 774         if (ret == MAP_FAILED)
 775                 die_errno("mmap failed");
 776         return ret;
 777 }
 778
 779 /*
 780  * With an in-core object data in "map", rehash it to make sure the
 781  * object name actually matches "sha1" to detect object corruption.
 782  * With "map" == NULL, try reading the object named with "sha1" using
 783  * the streaming interface and rehash it to do the same.
 784  */
 785 int check_sha1_signature(const unsigned char *sha1, void *map,
 786                          unsigned long size, const char *type)
 787 {
 788         unsigned char real_sha1[20];
 789         enum object_type obj_type;
 790         struct git_istream *st;
 791         git_SHA_CTX c;
 792         char hdr[32];
 793         int hdrlen;
 794
 795         if (map) {
 796                 hash_sha1_file(map, size, type, real_sha1);
 797                 return hashcmp(sha1, real_sha1) ? -1 : 0;
 798         }
 799
 800         st = open_istream(sha1, &obj_type, &size, NULL);
 801         if (!st)
 802                 return -1;
 803
 804         /* Generate the header */
 805         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 806
 807         /* Sha1.. */
 808         git_SHA1_Init(&c);
 809         git_SHA1_Update(&c, hdr, hdrlen);
 810         for (;;) {
 811                 char buf[1024 * 16];
 812                 ssize_t readlen = read_istream(st, buf, sizeof(buf));
 813
 814                 if (readlen < 0) {
 815                         close_istream(st);
 816                         return -1;
 817                 }
 818                 if (!readlen)
 819                         break;
 820                 git_SHA1_Update(&c, buf, readlen);
 821         }
 822         git_SHA1_Final(real_sha1, &c);
 823         close_istream(st);
 824         return hashcmp(sha1, real_sha1) ? -1 : 0;
 825 }
 826
 827 int git_open_cloexec(const char *name, int flags)
 828 {
 829         int fd;
 830         static int o_cloexec = O_CLOEXEC;
 831
 832         fd = open(name, flags | o_cloexec);
 833         if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 834                 /* Try again w/o O_CLOEXEC: the kernel might not support it */
 835                 o_cloexec &= ~O_CLOEXEC;
 836                 fd = open(name, flags | o_cloexec);
 837         }
 838
 839 #if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 840         {
 841                 static int fd_cloexec = FD_CLOEXEC;
 842
 843                 if (!o_cloexec && 0 <= fd && fd_cloexec) {
 844                         /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 845                         int flags = fcntl(fd, F_GETFD);
 846                         if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 847                                 fd_cloexec = 0;
 848                 }
 849         }
 850 #endif
 851         return fd;
 852 }
 853
 854 /*
 855  * Find "sha1" as a loose object in the local repository or in an alternate.
 856  * Returns 0 on success, negative on failure.
 857  *
 858  * The "path" out-parameter will give the path of the object we found (if any).
 859  * Note that it may point to static storage and is only valid until another
 860  * call to sha1_file_name(), etc.
 861  */
 862 static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 863                           const char **path)
 864 {
 865         struct alternate_object_database *alt;
 866         static struct strbuf buf = STRBUF_INIT;
 867
 868         strbuf_reset(&buf);
 869         sha1_file_name(&buf, sha1);
 870         *path = buf.buf;
 871
 872         if (!lstat(*path, st))
 873                 return 0;
 874
 875         prepare_alt_odb();
 876         errno = ENOENT;
 877         for (alt = alt_odb_list; alt; alt = alt->next) {
 878                 *path = alt_sha1_path(alt, sha1);
 879                 if (!lstat(*path, st))
 880                         return 0;
 881         }
 882
 883         return -1;
 884 }
 885
 886 /*
 887  * Like stat_sha1_file(), but actually open the object and return the
 888  * descriptor. See the caveats on the "path" parameter above.
 889  */
 890 static int open_sha1_file(const unsigned char *sha1, const char **path)
 891 {
 892         int fd;
 893         struct alternate_object_database *alt;
 894         int most_interesting_errno;
 895         static struct strbuf buf = STRBUF_INIT;
 896
 897         strbuf_reset(&buf);
 898         sha1_file_name(&buf, sha1);
 899         *path = buf.buf;
 900
 901         fd = git_open(*path);
 902         if (fd >= 0)
 903                 return fd;
 904         most_interesting_errno = errno;
 905
 906         prepare_alt_odb();
 907         for (alt = alt_odb_list; alt; alt = alt->next) {
 908                 *path = alt_sha1_path(alt, sha1);
 909                 fd = git_open(*path);
 910                 if (fd >= 0)
 911                         return fd;
 912                 if (most_interesting_errno == ENOENT)
 913                         most_interesting_errno = errno;
 914         }
 915         errno = most_interesting_errno;
 916         return -1;
 917 }
 918
 919 /*
 920  * Map the loose object at "path" if it is not NULL, or the path found by
 921  * searching for a loose object named "sha1".
 922  */
 923 static void *map_sha1_file_1(const char *path,
 924                              const unsigned char *sha1,
 925                              unsigned long *size)
 926 {
 927         void *map;
 928         int fd;
 929
 930         if (path)
 931                 fd = git_open(path);
 932         else
 933                 fd = open_sha1_file(sha1, &path);
 934         map = NULL;
 935         if (fd >= 0) {
 936                 struct stat st;
 937
 938                 if (!fstat(fd, &st)) {
 939                         *size = xsize_t(st.st_size);
 940                         if (!*size) {
 941                                 /* mmap() is forbidden on empty files */
 942                                 error("object file %s is empty", path);
 943                                 return NULL;
 944                         }
 945                         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 946                 }
 947                 close(fd);
 948         }
 949         return map;
 950 }
 951
 952 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 953 {
 954         return map_sha1_file_1(NULL, sha1, size);
 955 }
 956
 957 static int unpack_sha1_short_header(git_zstream *stream,
 958                                     unsigned char *map, unsigned long mapsize,
 959                                     void *buffer, unsigned long bufsiz)
 960 {
 961         /* Get the data stream */
 962         memset(stream, 0, sizeof(*stream));
 963         stream->next_in = map;
 964         stream->avail_in = mapsize;
 965         stream->next_out = buffer;
 966         stream->avail_out = bufsiz;
 967
 968         git_inflate_init(stream);
 969         return git_inflate(stream, 0);
 970 }
 971
 972 int unpack_sha1_header(git_zstream *stream,
 973                        unsigned char *map, unsigned long mapsize,
 974                        void *buffer, unsigned long bufsiz)
 975 {
 976         int status = unpack_sha1_short_header(stream, map, mapsize,
 977                                               buffer, bufsiz);
 978
 979         if (status < Z_OK)
 980                 return status;
 981
 982         /* Make sure we have the terminating NUL */
 983         if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 984                 return -1;
 985         return 0;
 986 }
 987
 988 static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 989                                         unsigned long mapsize, void *buffer,
 990                                         unsigned long bufsiz, struct strbuf *header)
 991 {
 992         int status;
 993
 994         status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 995         if (status < Z_OK)
 996                 return -1;
 997
 998         /*
 999          * Check if entire header is unpacked in the first iteration.
1000          */
1001         if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1002                 return 0;
1003
1004         /*
1005          * buffer[0..bufsiz] was not large enough.  Copy the partial
1006          * result out to header, and then append the result of further
1007          * reading the stream.
1008          */
1009         strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1010         stream->next_out = buffer;
1011         stream->avail_out = bufsiz;
1012
1013         do {
1014                 status = git_inflate(stream, 0);
1015                 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1016                 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1017                         return 0;
1018                 stream->next_out = buffer;
1019                 stream->avail_out = bufsiz;
1020         } while (status != Z_STREAM_END);
1021         return -1;
1022 }
1023
1024 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1025 {
1026         int bytes = strlen(buffer) + 1;
1027         unsigned char *buf = xmallocz(size);
1028         unsigned long n;
1029         int status = Z_OK;
1030
1031         n = stream->total_out - bytes;
1032         if (n > size)
1033                 n = size;
1034         memcpy(buf, (char *) buffer + bytes, n);
1035         bytes = n;
1036         if (bytes <= size) {
1037                 /*
1038                  * The above condition must be (bytes <= size), not
1039                  * (bytes < size).  In other words, even though we
1040                  * expect no more output and set avail_out to zero,
1041                  * the input zlib stream may have bytes that express
1042                  * "this concludes the stream", and we *do* want to
1043                  * eat that input.
1044                  *
1045                  * Otherwise we would not be able to test that we
1046                  * consumed all the input to reach the expected size;
1047                  * we also want to check that zlib tells us that all
1048                  * went well with status == Z_STREAM_END at the end.
1049                  */
1050                 stream->next_out = buf + bytes;
1051                 stream->avail_out = size - bytes;
1052                 while (status == Z_OK)
1053                         status = git_inflate(stream, Z_FINISH);
1054         }
1055         if (status == Z_STREAM_END && !stream->avail_in) {
1056                 git_inflate_end(stream);
1057                 return buf;
1058         }
1059
1060         if (status < 0)
1061                 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1062         else if (stream->avail_in)
1063                 error("garbage at end of loose object '%s'",
1064                       sha1_to_hex(sha1));
1065         free(buf);
1066         return NULL;
1067 }
1068
1069 /*
1070  * We used to just use "sscanf()", but that's actually way
1071  * too permissive for what we want to check. So do an anal
1072  * object header parse by hand.
1073  */
1074 static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1075                                unsigned int flags)
1076 {
1077         const char *type_buf = hdr;
1078         unsigned long size;
1079         int type, type_len = 0;
1080
1081         /*
1082          * The type can be of any size but is followed by
1083          * a space.
1084          */
1085         for (;;) {
1086                 char c = *hdr++;
1087                 if (!c)
1088                         return -1;
1089                 if (c == ' ')
1090                         break;
1091                 type_len++;
1092         }
1093
1094         type = type_from_string_gently(type_buf, type_len, 1);
1095         if (oi->typename)
1096                 strbuf_add(oi->typename, type_buf, type_len);
1097         /*
1098          * Set type to 0 if its an unknown object and
1099          * we're obtaining the type using '--allow-unknown-type'
1100          * option.
1101          */
1102         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1103                 type = 0;
1104         else if (type < 0)
1105                 die("invalid object type");
1106         if (oi->typep)
1107                 *oi->typep = type;
1108
1109         /*
1110          * The length must follow immediately, and be in canonical
1111          * decimal format (ie "010" is not valid).
1112          */
1113         size = *hdr++ - '0';
1114         if (size > 9)
1115                 return -1;
1116         if (size) {
1117                 for (;;) {
1118                         unsigned long c = *hdr - '0';
1119                         if (c > 9)
1120                                 break;
1121                         hdr++;
1122                         size = size * 10 + c;
1123                 }
1124         }
1125
1126         if (oi->sizep)
1127                 *oi->sizep = size;
1128
1129         /*
1130          * The length must be followed by a zero byte
1131          */
1132         return *hdr ? -1 : type;
1133 }
1134
1135 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1136 {
1137         struct object_info oi = OBJECT_INFO_INIT;
1138
1139         oi.sizep = sizep;
1140         return parse_sha1_header_extended(hdr, &oi, 0);
1141 }
1142
1143 static int sha1_loose_object_info(const unsigned char *sha1,
1144                                   struct object_info *oi,
1145                                   int flags)
1146 {
1147         int status = 0;
1148         unsigned long mapsize;
1149         void *map;
1150         git_zstream stream;
1151         char hdr[32];
1152         struct strbuf hdrbuf = STRBUF_INIT;
1153         unsigned long size_scratch;
1154
1155         if (oi->delta_base_sha1)
1156                 hashclr(oi->delta_base_sha1);
1157
1158         /*
1159          * If we don't care about type or size, then we don't
1160          * need to look inside the object at all. Note that we
1161          * do not optimize out the stat call, even if the
1162          * caller doesn't care about the disk-size, since our
1163          * return value implicitly indicates whether the
1164          * object even exists.
1165          */
1166         if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1167                 const char *path;
1168                 struct stat st;
1169                 if (stat_sha1_file(sha1, &st, &path) < 0)
1170                         return -1;
1171                 if (oi->disk_sizep)
1172                         *oi->disk_sizep = st.st_size;
1173                 return 0;
1174         }
1175
1176         map = map_sha1_file(sha1, &mapsize);
1177         if (!map)
1178                 return -1;
1179
1180         if (!oi->sizep)
1181                 oi->sizep = &size_scratch;
1182
1183         if (oi->disk_sizep)
1184                 *oi->disk_sizep = mapsize;
1185         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1186                 if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1187                         status = error("unable to unpack %s header with --allow-unknown-type",
1188                                        sha1_to_hex(sha1));
1189         } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1190                 status = error("unable to unpack %s header",
1191                                sha1_to_hex(sha1));
1192         if (status < 0)
1193                 ; /* Do nothing */
1194         else if (hdrbuf.len) {
1195                 if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1196                         status = error("unable to parse %s header with --allow-unknown-type",
1197                                        sha1_to_hex(sha1));
1198         } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1199                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1200
1201         if (status >= 0 && oi->contentp) {
1202                 *oi->contentp = unpack_sha1_rest(&stream, hdr,
1203                                                  *oi->sizep, sha1);
1204                 if (!*oi->contentp) {
1205                         git_inflate_end(&stream);
1206                         status = -1;
1207                 }
1208         } else
1209                 git_inflate_end(&stream);
1210
1211         munmap(map, mapsize);
1212         if (status && oi->typep)
1213                 *oi->typep = status;
1214         if (oi->sizep == &size_scratch)
1215                 oi->sizep = NULL;
1216         strbuf_release(&hdrbuf);
1217         oi->whence = OI_LOOSE;
1218         return (status < 0) ? status : 0;
1219 }
1220
1221 int fetch_if_missing = 1;
1222
1223 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1224 {
1225         static struct object_info blank_oi = OBJECT_INFO_INIT;
1226         struct pack_entry e;
1227         int rtype;
1228         const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1229                                     lookup_replace_object(sha1) :
1230                                     sha1;
1231         int already_retried = 0;
1232
1233         if (is_null_sha1(real))
1234                 return -1;
1235
1236         if (!oi)
1237                 oi = &blank_oi;
1238
1239         if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1240                 struct cached_object *co = find_cached_object(real);
1241                 if (co) {
1242                         if (oi->typep)
1243                                 *(oi->typep) = co->type;
1244                         if (oi->sizep)
1245                                 *(oi->sizep) = co->size;
1246                         if (oi->disk_sizep)
1247                                 *(oi->disk_sizep) = 0;
1248                         if (oi->delta_base_sha1)
1249                                 hashclr(oi->delta_base_sha1);
1250                         if (oi->typename)
1251                                 strbuf_addstr(oi->typename, typename(co->type));
1252                         if (oi->contentp)
1253                                 *oi->contentp = xmemdupz(co->buf, co->size);
1254                         oi->whence = OI_CACHED;
1255                         return 0;
1256                 }
1257         }
1258
1259         while (1) {
1260                 if (find_pack_entry(real, &e))
1261                         break;
1262
1263                 /* Most likely it's a loose object. */
1264                 if (!sha1_loose_object_info(real, oi, flags))
1265                         return 0;
1266
1267                 /* Not a loose object; someone else may have just packed it. */
1268                 reprepare_packed_git();
1269                 if (find_pack_entry(real, &e))
1270                         break;
1271
1272                 /* Check if it is a missing object */
1273                 if (fetch_if_missing && repository_format_partial_clone &&
1274                     !already_retried) {
1275                         /*
1276                          * TODO Investigate haveing fetch_object() return
1277                          * TODO error/success and stopping the music here.
1278                          */
1279                         fetch_object(repository_format_partial_clone, real);
1280                         already_retried = 1;
1281                         continue;
1282                 }
1283
1284                 return -1;
1285         }
1286
1287         if (oi == &blank_oi)
1288                 /*
1289                  * We know that the caller doesn't actually need the
1290                  * information below, so return early.
1291                  */
1292                 return 0;
1293         rtype = packed_object_info(e.p, e.offset, oi);
1294         if (rtype < 0) {
1295                 mark_bad_packed_object(e.p, real);
1296                 return sha1_object_info_extended(real, oi, 0);
1297         } else if (oi->whence == OI_PACKED) {
1298                 oi->u.packed.offset = e.offset;
1299                 oi->u.packed.pack = e.p;
1300                 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1301                                          rtype == OBJ_OFS_DELTA);
1302         }
1303
1304         return 0;
1305 }
1306
1307 /* returns enum object_type or negative */
1308 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1309 {
1310         enum object_type type;
1311         struct object_info oi = OBJECT_INFO_INIT;
1312
1313         oi.typep = &type;
1314         oi.sizep = sizep;
1315         if (sha1_object_info_extended(sha1, &oi,
1316                                       OBJECT_INFO_LOOKUP_REPLACE) < 0)
1317                 return -1;
1318         return type;
1319 }
1320
1321 static void *read_object(const unsigned char *sha1, enum object_type *type,
1322                          unsigned long *size)
1323 {
1324         struct object_info oi = OBJECT_INFO_INIT;
1325         void *content;
1326         oi.typep = type;
1327         oi.sizep = size;
1328         oi.contentp = &content;
1329
1330         if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1331                 return NULL;
1332         return content;
1333 }
1334
1335 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1336                       unsigned char *sha1)
1337 {
1338         struct cached_object *co;
1339
1340         hash_sha1_file(buf, len, typename(type), sha1);
1341         if (has_sha1_file(sha1) || find_cached_object(sha1))
1342                 return 0;
1343         ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1344         co = &cached_objects[cached_object_nr++];
1345         co->size = len;
1346         co->type = type;
1347         co->buf = xmalloc(len);
1348         memcpy(co->buf, buf, len);
1349         hashcpy(co->sha1, sha1);
1350         return 0;
1351 }
1352
1353 /*
1354  * This function dies on corrupt objects; the callers who want to
1355  * deal with them should arrange to call read_object() and give error
1356  * messages themselves.
1357  */
1358 void *read_sha1_file_extended(const unsigned char *sha1,
1359                               enum object_type *type,
1360                               unsigned long *size,
1361                               int lookup_replace)
1362 {
1363         void *data;
1364         const struct packed_git *p;
1365         const char *path;
1366         struct stat st;
1367         const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1368                                                    : sha1;
1369
1370         errno = 0;
1371         data = read_object(repl, type, size);
1372         if (data)
1373                 return data;
1374
1375         if (errno && errno != ENOENT)
1376                 die_errno("failed to read object %s", sha1_to_hex(sha1));
1377
1378         /* die if we replaced an object with one that does not exist */
1379         if (repl != sha1)
1380                 die("replacement %s not found for %s",
1381                     sha1_to_hex(repl), sha1_to_hex(sha1));
1382
1383         if (!stat_sha1_file(repl, &st, &path))
1384                 die("loose object %s (stored in %s) is corrupt",
1385                     sha1_to_hex(repl), path);
1386
1387         if ((p = has_packed_and_bad(repl)) != NULL)
1388                 die("packed object %s (stored in %s) is corrupt",
1389                     sha1_to_hex(repl), p->pack_name);
1390
1391         return NULL;
1392 }
1393
1394 void *read_object_with_reference(const unsigned char *sha1,
1395                                  const char *required_type_name,
1396                                  unsigned long *size,
1397                                  unsigned char *actual_sha1_return)
1398 {
1399         enum object_type type, required_type;
1400         void *buffer;
1401         unsigned long isize;
1402         unsigned char actual_sha1[20];
1403
1404         required_type = type_from_string(required_type_name);
1405         hashcpy(actual_sha1, sha1);
1406         while (1) {
1407                 int ref_length = -1;
1408                 const char *ref_type = NULL;
1409
1410                 buffer = read_sha1_file(actual_sha1, &type, &isize);
1411                 if (!buffer)
1412                         return NULL;
1413                 if (type == required_type) {
1414                         *size = isize;
1415                         if (actual_sha1_return)
1416                                 hashcpy(actual_sha1_return, actual_sha1);
1417                         return buffer;
1418                 }
1419                 /* Handle references */
1420                 else if (type == OBJ_COMMIT)
1421                         ref_type = "tree ";
1422                 else if (type == OBJ_TAG)
1423                         ref_type = "object ";
1424                 else {
1425                         free(buffer);
1426                         return NULL;
1427                 }
1428                 ref_length = strlen(ref_type);
1429
1430                 if (ref_length + 40 > isize ||
1431                     memcmp(buffer, ref_type, ref_length) ||
1432                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1433                         free(buffer);
1434                         return NULL;
1435                 }
1436                 free(buffer);
1437                 /* Now we have the ID of the referred-to object in
1438                  * actual_sha1.  Check again. */
1439         }
1440 }
1441
1442 static void write_sha1_file_prepare(const void *buf, unsigned long len,
1443                                     const char *type, unsigned char *sha1,
1444                                     char *hdr, int *hdrlen)
1445 {
1446         git_SHA_CTX c;
1447
1448         /* Generate the header */
1449         *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1450
1451         /* Sha1.. */
1452         git_SHA1_Init(&c);
1453         git_SHA1_Update(&c, hdr, *hdrlen);
1454         git_SHA1_Update(&c, buf, len);
1455         git_SHA1_Final(sha1, &c);
1456 }
1457
1458 /*
1459  * Move the just written object into its final resting place.
1460  */
1461 int finalize_object_file(const char *tmpfile, const char *filename)
1462 {
1463         int ret = 0;
1464
1465         if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1466                 goto try_rename;
1467         else if (link(tmpfile, filename))
1468                 ret = errno;
1469
1470         /*
1471          * Coda hack - coda doesn't like cross-directory links,
1472          * so we fall back to a rename, which will mean that it
1473          * won't be able to check collisions, but that's not a
1474          * big deal.
1475          *
1476          * The same holds for FAT formatted media.
1477          *
1478          * When this succeeds, we just return.  We have nothing
1479          * left to unlink.
1480          */
1481         if (ret && ret != EEXIST) {
1482         try_rename:
1483                 if (!rename(tmpfile, filename))
1484                         goto out;
1485                 ret = errno;
1486         }
1487         unlink_or_warn(tmpfile);
1488         if (ret) {
1489                 if (ret != EEXIST) {
1490                         return error_errno("unable to write sha1 filename %s", filename);
1491                 }
1492                 /* FIXME!!! Collision check here ? */
1493         }
1494
1495 out:
1496         if (adjust_shared_perm(filename))
1497                 return error("unable to set permission to '%s'", filename);
1498         return 0;
1499 }
1500
1501 static int write_buffer(int fd, const void *buf, size_t len)
1502 {
1503         if (write_in_full(fd, buf, len) < 0)
1504                 return error_errno("file write error");
1505         return 0;
1506 }
1507
1508 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1509                    unsigned char *sha1)
1510 {
1511         char hdr[32];
1512         int hdrlen = sizeof(hdr);
1513         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1514         return 0;
1515 }
1516
1517 /* Finalize a file on disk, and close it. */
1518 static void close_sha1_file(int fd)
1519 {
1520         if (fsync_object_files)
1521                 fsync_or_die(fd, "sha1 file");
1522         if (close(fd) != 0)
1523                 die_errno("error when closing sha1 file");
1524 }
1525
1526 /* Size of directory component, including the ending '/' */
1527 static inline int directory_size(const char *filename)
1528 {
1529         const char *s = strrchr(filename, '/');
1530         if (!s)
1531                 return 0;
1532         return s - filename + 1;
1533 }
1534
1535 /*
1536  * This creates a temporary file in the same directory as the final
1537  * 'filename'
1538  *
1539  * We want to avoid cross-directory filename renames, because those
1540  * can have problems on various filesystems (FAT, NFS, Coda).
1541  */
1542 static int create_tmpfile(struct strbuf *tmp, const char *filename)
1543 {
1544         int fd, dirlen = directory_size(filename);
1545
1546         strbuf_reset(tmp);
1547         strbuf_add(tmp, filename, dirlen);
1548         strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1549         fd = git_mkstemp_mode(tmp->buf, 0444);
1550         if (fd < 0 && dirlen && errno == ENOENT) {
1551                 /*
1552                  * Make sure the directory exists; note that the contents
1553                  * of the buffer are undefined after mkstemp returns an
1554                  * error, so we have to rewrite the whole buffer from
1555                  * scratch.
1556                  */
1557                 strbuf_reset(tmp);
1558                 strbuf_add(tmp, filename, dirlen - 1);
1559                 if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1560                         return -1;
1561                 if (adjust_shared_perm(tmp->buf))
1562                         return -1;
1563
1564                 /* Try again */
1565                 strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1566                 fd = git_mkstemp_mode(tmp->buf, 0444);
1567         }
1568         return fd;
1569 }
1570
1571 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1572                               const void *buf, unsigned long len, time_t mtime)
1573 {
1574         int fd, ret;
1575         unsigned char compressed[4096];
1576         git_zstream stream;
1577         git_SHA_CTX c;
1578         unsigned char parano_sha1[20];
1579         static struct strbuf tmp_file = STRBUF_INIT;
1580         static struct strbuf filename = STRBUF_INIT;
1581
1582         strbuf_reset(&filename);
1583         sha1_file_name(&filename, sha1);
1584
1585         fd = create_tmpfile(&tmp_file, filename.buf);
1586         if (fd < 0) {
1587                 if (errno == EACCES)
1588                         return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1589                 else
1590                         return error_errno("unable to create temporary file");
1591         }
1592
1593         /* Set it up */
1594         git_deflate_init(&stream, zlib_compression_level);
1595         stream.next_out = compressed;
1596         stream.avail_out = sizeof(compressed);
1597         git_SHA1_Init(&c);
1598
1599         /* First header.. */
1600         stream.next_in = (unsigned char *)hdr;
1601         stream.avail_in = hdrlen;
1602         while (git_deflate(&stream, 0) == Z_OK)
1603                 ; /* nothing */
1604         git_SHA1_Update(&c, hdr, hdrlen);
1605
1606         /* Then the data itself.. */
1607         stream.next_in = (void *)buf;
1608         stream.avail_in = len;
1609         do {
1610                 unsigned char *in0 = stream.next_in;
1611                 ret = git_deflate(&stream, Z_FINISH);
1612                 git_SHA1_Update(&c, in0, stream.next_in - in0);
1613                 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1614                         die("unable to write sha1 file");
1615                 stream.next_out = compressed;
1616                 stream.avail_out = sizeof(compressed);
1617         } while (ret == Z_OK);
1618
1619         if (ret != Z_STREAM_END)
1620                 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1621         ret = git_deflate_end_gently(&stream);
1622         if (ret != Z_OK)
1623                 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1624         git_SHA1_Final(parano_sha1, &c);
1625         if (hashcmp(sha1, parano_sha1) != 0)
1626                 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1627
1628         close_sha1_file(fd);
1629
1630         if (mtime) {
1631                 struct utimbuf utb;
1632                 utb.actime = mtime;
1633                 utb.modtime = mtime;
1634                 if (utime(tmp_file.buf, &utb) < 0)
1635                         warning_errno("failed utime() on %s", tmp_file.buf);
1636         }
1637
1638         return finalize_object_file(tmp_file.buf, filename.buf);
1639 }
1640
1641 static int freshen_loose_object(const unsigned char *sha1)
1642 {
1643         return check_and_freshen(sha1, 1);
1644 }
1645
1646 static int freshen_packed_object(const unsigned char *sha1)
1647 {
1648         struct pack_entry e;
1649         if (!find_pack_entry(sha1, &e))
1650                 return 0;
1651         if (e.p->freshened)
1652                 return 1;
1653         if (!freshen_file(e.p->pack_name))
1654                 return 0;
1655         e.p->freshened = 1;
1656         return 1;
1657 }
1658
1659 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1660 {
1661         char hdr[32];
1662         int hdrlen = sizeof(hdr);
1663
1664         /* Normally if we have it in the pack then we do not bother writing
1665          * it out into .git/objects/??/?{38} file.
1666          */
1667         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1668         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1669                 return 0;
1670         return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1671 }
1672
1673 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1674                              struct object_id *oid, unsigned flags)
1675 {
1676         char *header;
1677         int hdrlen, status = 0;
1678
1679         /* type string, SP, %lu of the length plus NUL must fit this */
1680         hdrlen = strlen(type) + 32;
1681         header = xmalloc(hdrlen);
1682         write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
1683
1684         if (!(flags & HASH_WRITE_OBJECT))
1685                 goto cleanup;
1686         if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1687                 goto cleanup;
1688         status = write_loose_object(oid->hash, header, hdrlen, buf, len, 0);
1689
1690 cleanup:
1691         free(header);
1692         return status;
1693 }
1694
1695 int force_object_loose(const unsigned char *sha1, time_t mtime)
1696 {
1697         void *buf;
1698         unsigned long len;
1699         enum object_type type;
1700         char hdr[32];
1701         int hdrlen;
1702         int ret;
1703
1704         if (has_loose_object(sha1))
1705                 return 0;
1706         buf = read_object(sha1, &type, &len);
1707         if (!buf)
1708                 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1709         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1710         ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1711         free(buf);
1712
1713         return ret;
1714 }
1715
1716 int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1717 {
1718         if (!startup_info->have_repository)
1719                 return 0;
1720         return sha1_object_info_extended(sha1, NULL,
1721                                          flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1722 }
1723
1724 int has_object_file(const struct object_id *oid)
1725 {
1726         return has_sha1_file(oid->hash);
1727 }
1728
1729 int has_object_file_with_flags(const struct object_id *oid, int flags)
1730 {
1731         return has_sha1_file_with_flags(oid->hash, flags);
1732 }
1733
1734 static void check_tree(const void *buf, size_t size)
1735 {
1736         struct tree_desc desc;
1737         struct name_entry entry;
1738
1739         init_tree_desc(&desc, buf, size);
1740         while (tree_entry(&desc, &entry))
1741                 /* do nothing
1742                  * tree_entry() will die() on malformed entries */
1743                 ;
1744 }
1745
1746 static void check_commit(const void *buf, size_t size)
1747 {
1748         struct commit c;
1749         memset(&c, 0, sizeof(c));
1750         if (parse_commit_buffer(&c, buf, size))
1751                 die("corrupt commit");
1752 }
1753
1754 static void check_tag(const void *buf, size_t size)
1755 {
1756         struct tag t;
1757         memset(&t, 0, sizeof(t));
1758         if (parse_tag_buffer(&t, buf, size))
1759                 die("corrupt tag");
1760 }
1761
1762 static int index_mem(struct object_id *oid, void *buf, size_t size,
1763                      enum object_type type,
1764                      const char *path, unsigned flags)
1765 {
1766         int ret, re_allocated = 0;
1767         int write_object = flags & HASH_WRITE_OBJECT;
1768
1769         if (!type)
1770                 type = OBJ_BLOB;
1771
1772         /*
1773          * Convert blobs to git internal format
1774          */
1775         if ((type == OBJ_BLOB) && path) {
1776                 struct strbuf nbuf = STRBUF_INIT;
1777                 if (convert_to_git(&the_index, path, buf, size, &nbuf,
1778                                    get_conv_flags(flags))) {
1779                         buf = strbuf_detach(&nbuf, &size);
1780                         re_allocated = 1;
1781                 }
1782         }
1783         if (flags & HASH_FORMAT_CHECK) {
1784                 if (type == OBJ_TREE)
1785                         check_tree(buf, size);
1786                 if (type == OBJ_COMMIT)
1787                         check_commit(buf, size);
1788                 if (type == OBJ_TAG)
1789                         check_tag(buf, size);
1790         }
1791
1792         if (write_object)
1793                 ret = write_sha1_file(buf, size, typename(type), oid->hash);
1794         else
1795                 ret = hash_sha1_file(buf, size, typename(type), oid->hash);
1796         if (re_allocated)
1797                 free(buf);
1798         return ret;
1799 }
1800
1801 static int index_stream_convert_blob(struct object_id *oid, int fd,
1802                                      const char *path, unsigned flags)
1803 {
1804         int ret;
1805         const int write_object = flags & HASH_WRITE_OBJECT;
1806         struct strbuf sbuf = STRBUF_INIT;
1807
1808         assert(path);
1809         assert(would_convert_to_git_filter_fd(path));
1810
1811         convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1812                                  get_conv_flags(flags));
1813
1814         if (write_object)
1815                 ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1816                                       oid->hash);
1817         else
1818                 ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1819                                      oid->hash);
1820         strbuf_release(&sbuf);
1821         return ret;
1822 }
1823
1824 static int index_pipe(struct object_id *oid, int fd, enum object_type type,
1825                       const char *path, unsigned flags)
1826 {
1827         struct strbuf sbuf = STRBUF_INIT;
1828         int ret;
1829
1830         if (strbuf_read(&sbuf, fd, 4096) >= 0)
1831                 ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
1832         else
1833                 ret = -1;
1834         strbuf_release(&sbuf);
1835         return ret;
1836 }
1837
1838 #define SMALL_FILE_SIZE (32*1024)
1839
1840 static int index_core(struct object_id *oid, int fd, size_t size,
1841                       enum object_type type, const char *path,
1842                       unsigned flags)
1843 {
1844         int ret;
1845
1846         if (!size) {
1847                 ret = index_mem(oid, "", size, type, path, flags);
1848         } else if (size <= SMALL_FILE_SIZE) {
1849                 char *buf = xmalloc(size);
1850                 ssize_t read_result = read_in_full(fd, buf, size);
1851                 if (read_result < 0)
1852                         ret = error_errno("read error while indexing %s",
1853                                           path ? path : "<unknown>");
1854                 else if (read_result != size)
1855                         ret = error("short read while indexing %s",
1856                                     path ? path : "<unknown>");
1857                 else
1858                         ret = index_mem(oid, buf, size, type, path, flags);
1859                 free(buf);
1860         } else {
1861                 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1862                 ret = index_mem(oid, buf, size, type, path, flags);
1863                 munmap(buf, size);
1864         }
1865         return ret;
1866 }
1867
1868 /*
1869  * This creates one packfile per large blob unless bulk-checkin
1870  * machinery is "plugged".
1871  *
1872  * This also bypasses the usual "convert-to-git" dance, and that is on
1873  * purpose. We could write a streaming version of the converting
1874  * functions and insert that before feeding the data to fast-import
1875  * (or equivalent in-core API described above). However, that is
1876  * somewhat complicated, as we do not know the size of the filter
1877  * result, which we need to know beforehand when writing a git object.
1878  * Since the primary motivation for trying to stream from the working
1879  * tree file and to avoid mmaping it in core is to deal with large
1880  * binary blobs, they generally do not want to get any conversion, and
1881  * callers should avoid this code path when filters are requested.
1882  */
1883 static int index_stream(struct object_id *oid, int fd, size_t size,
1884                         enum object_type type, const char *path,
1885                         unsigned flags)
1886 {
1887         return index_bulk_checkin(oid->hash, fd, size, type, path, flags);
1888 }
1889
1890 int index_fd(struct object_id *oid, int fd, struct stat *st,
1891              enum object_type type, const char *path, unsigned flags)
1892 {
1893         int ret;
1894
1895         /*
1896          * Call xsize_t() only when needed to avoid potentially unnecessary
1897          * die() for large files.
1898          */
1899         if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1900                 ret = index_stream_convert_blob(oid, fd, path, flags);
1901         else if (!S_ISREG(st->st_mode))
1902                 ret = index_pipe(oid, fd, type, path, flags);
1903         else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1904                  (path && would_convert_to_git(&the_index, path)))
1905                 ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
1906                                  flags);
1907         else
1908                 ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
1909                                    flags);
1910         close(fd);
1911         return ret;
1912 }
1913
1914 int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
1915 {
1916         int fd;
1917         struct strbuf sb = STRBUF_INIT;
1918         int rc = 0;
1919
1920         switch (st->st_mode & S_IFMT) {
1921         case S_IFREG:
1922                 fd = open(path, O_RDONLY);
1923                 if (fd < 0)
1924                         return error_errno("open(\"%s\")", path);
1925                 if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
1926                         return error("%s: failed to insert into database",
1927                                      path);
1928                 break;
1929         case S_IFLNK:
1930                 if (strbuf_readlink(&sb, path, st->st_size))
1931                         return error_errno("readlink(\"%s\")", path);
1932                 if (!(flags & HASH_WRITE_OBJECT))
1933                         hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
1934                 else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
1935                         rc = error("%s: failed to insert into database", path);
1936                 strbuf_release(&sb);
1937                 break;
1938         case S_IFDIR:
1939                 return resolve_gitlink_ref(path, "HEAD", oid);
1940         default:
1941                 return error("%s: unsupported file type", path);
1942         }
1943         return rc;
1944 }
1945
1946 int read_pack_header(int fd, struct pack_header *header)
1947 {
1948         if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
1949                 /* "eof before pack header was fully read" */
1950                 return PH_ERROR_EOF;
1951
1952         if (header->hdr_signature != htonl(PACK_SIGNATURE))
1953                 /* "protocol error (pack signature mismatch detected)" */
1954                 return PH_ERROR_PACK_SIGNATURE;
1955         if (!pack_version_ok(header->hdr_version))
1956                 /* "protocol error (pack version unsupported)" */
1957                 return PH_ERROR_PROTOCOL;
1958         return 0;
1959 }
1960
1961 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1962 {
1963         enum object_type type = sha1_object_info(sha1, NULL);
1964         if (type < 0)
1965                 die("%s is not a valid object", sha1_to_hex(sha1));
1966         if (type != expect)
1967                 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1968                     typename(expect));
1969 }
1970
1971 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1972                                 struct strbuf *path,
1973                                 each_loose_object_fn obj_cb,
1974                                 each_loose_cruft_fn cruft_cb,
1975                                 each_loose_subdir_fn subdir_cb,
1976                                 void *data)
1977 {
1978         size_t origlen, baselen;
1979         DIR *dir;
1980         struct dirent *de;
1981         int r = 0;
1982         struct object_id oid;
1983
1984         if (subdir_nr > 0xff)
1985                 BUG("invalid loose object subdirectory: %x", subdir_nr);
1986
1987         origlen = path->len;
1988         strbuf_complete(path, '/');
1989         strbuf_addf(path, "%02x", subdir_nr);
1990
1991         dir = opendir(path->buf);
1992         if (!dir) {
1993                 if (errno != ENOENT)
1994                         r = error_errno("unable to open %s", path->buf);
1995                 strbuf_setlen(path, origlen);
1996                 return r;
1997         }
1998
1999         oid.hash[0] = subdir_nr;
2000         strbuf_addch(path, '/');
2001         baselen = path->len;
2002
2003         while ((de = readdir(dir))) {
2004                 size_t namelen;
2005                 if (is_dot_or_dotdot(de->d_name))
2006                         continue;
2007
2008                 namelen = strlen(de->d_name);
2009                 strbuf_setlen(path, baselen);
2010                 strbuf_add(path, de->d_name, namelen);
2011                 if (namelen == GIT_SHA1_HEXSZ - 2 &&
2012                     !hex_to_bytes(oid.hash + 1, de->d_name,
2013                                   GIT_SHA1_RAWSZ - 1)) {
2014                         if (obj_cb) {
2015                                 r = obj_cb(&oid, path->buf, data);
2016                                 if (r)
2017                                         break;
2018                         }
2019                         continue;
2020                 }
2021
2022                 if (cruft_cb) {
2023                         r = cruft_cb(de->d_name, path->buf, data);
2024                         if (r)
2025                                 break;
2026                 }
2027         }
2028         closedir(dir);
2029
2030         strbuf_setlen(path, baselen - 1);
2031         if (!r && subdir_cb)
2032                 r = subdir_cb(subdir_nr, path->buf, data);
2033
2034         strbuf_setlen(path, origlen);
2035
2036         return r;
2037 }
2038
2039 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2040                             each_loose_object_fn obj_cb,
2041                             each_loose_cruft_fn cruft_cb,
2042                             each_loose_subdir_fn subdir_cb,
2043                             void *data)
2044 {
2045         int r = 0;
2046         int i;
2047
2048         for (i = 0; i < 256; i++) {
2049                 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2050                                                 subdir_cb, data);
2051                 if (r)
2052                         break;
2053         }
2054
2055         return r;
2056 }
2057
2058 int for_each_loose_file_in_objdir(const char *path,
2059                                   each_loose_object_fn obj_cb,
2060                                   each_loose_cruft_fn cruft_cb,
2061                                   each_loose_subdir_fn subdir_cb,
2062                                   void *data)
2063 {
2064         struct strbuf buf = STRBUF_INIT;
2065         int r;
2066
2067         strbuf_addstr(&buf, path);
2068         r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2069                                               subdir_cb, data);
2070         strbuf_release(&buf);
2071
2072         return r;
2073 }
2074
2075 struct loose_alt_odb_data {
2076         each_loose_object_fn *cb;
2077         void *data;
2078 };
2079
2080 static int loose_from_alt_odb(struct alternate_object_database *alt,
2081                               void *vdata)
2082 {
2083         struct loose_alt_odb_data *data = vdata;
2084         struct strbuf buf = STRBUF_INIT;
2085         int r;
2086
2087         strbuf_addstr(&buf, alt->path);
2088         r = for_each_loose_file_in_objdir_buf(&buf,
2089                                               data->cb, NULL, NULL,
2090                                               data->data);
2091         strbuf_release(&buf);
2092         return r;
2093 }
2094
2095 int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2096 {
2097         struct loose_alt_odb_data alt;
2098         int r;
2099
2100         r = for_each_loose_file_in_objdir(get_object_directory(),
2101                                           cb, NULL, NULL, data);
2102         if (r)
2103                 return r;
2104
2105         if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2106                 return 0;
2107
2108         alt.cb = cb;
2109         alt.data = data;
2110         return foreach_alt_odb(loose_from_alt_odb, &alt);
2111 }
2112
2113 static int check_stream_sha1(git_zstream *stream,
2114                              const char *hdr,
2115                              unsigned long size,
2116                              const char *path,
2117                              const unsigned char *expected_sha1)
2118 {
2119         git_SHA_CTX c;
2120         unsigned char real_sha1[GIT_MAX_RAWSZ];
2121         unsigned char buf[4096];
2122         unsigned long total_read;
2123         int status = Z_OK;
2124
2125         git_SHA1_Init(&c);
2126         git_SHA1_Update(&c, hdr, stream->total_out);
2127
2128         /*
2129          * We already read some bytes into hdr, but the ones up to the NUL
2130          * do not count against the object's content size.
2131          */
2132         total_read = stream->total_out - strlen(hdr) - 1;
2133
2134         /*
2135          * This size comparison must be "<=" to read the final zlib packets;
2136          * see the comment in unpack_sha1_rest for details.
2137          */
2138         while (total_read <= size &&
2139                (status == Z_OK || status == Z_BUF_ERROR)) {
2140                 stream->next_out = buf;
2141                 stream->avail_out = sizeof(buf);
2142                 if (size - total_read < stream->avail_out)
2143                         stream->avail_out = size - total_read;
2144                 status = git_inflate(stream, Z_FINISH);
2145                 git_SHA1_Update(&c, buf, stream->next_out - buf);
2146                 total_read += stream->next_out - buf;
2147         }
2148         git_inflate_end(stream);
2149
2150         if (status != Z_STREAM_END) {
2151                 error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2152                 return -1;
2153         }
2154         if (stream->avail_in) {
2155                 error("garbage at end of loose object '%s'",
2156                       sha1_to_hex(expected_sha1));
2157                 return -1;
2158         }
2159
2160         git_SHA1_Final(real_sha1, &c);
2161         if (hashcmp(expected_sha1, real_sha1)) {
2162                 error("sha1 mismatch for %s (expected %s)", path,
2163                       sha1_to_hex(expected_sha1));
2164                 return -1;
2165         }
2166
2167         return 0;
2168 }
2169
2170 int read_loose_object(const char *path,
2171                       const unsigned char *expected_sha1,
2172                       enum object_type *type,
2173                       unsigned long *size,
2174                       void **contents)
2175 {
2176         int ret = -1;
2177         void *map = NULL;
2178         unsigned long mapsize;
2179         git_zstream stream;
2180         char hdr[32];
2181
2182         *contents = NULL;
2183
2184         map = map_sha1_file_1(path, NULL, &mapsize);
2185         if (!map) {
2186                 error_errno("unable to mmap %s", path);
2187                 goto out;
2188         }
2189
2190         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2191                 error("unable to unpack header of %s", path);
2192                 goto out;
2193         }
2194
2195         *type = parse_sha1_header(hdr, size);
2196         if (*type < 0) {
2197                 error("unable to parse header of %s", path);
2198                 git_inflate_end(&stream);
2199                 goto out;
2200         }
2201
2202         if (*type == OBJ_BLOB) {
2203                 if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2204                         goto out;
2205         } else {
2206                 *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2207                 if (!*contents) {
2208                         error("unable to unpack contents of %s", path);
2209                         git_inflate_end(&stream);
2210                         goto out;
2211                 }
2212                 if (check_sha1_signature(expected_sha1, *contents,
2213                                          *size, typename(*type))) {
2214                         error("sha1 mismatch for %s (expected %s)", path,
2215                               sha1_to_hex(expected_sha1));
2216                         free(*contents);
2217                         goto out;
2218                 }
2219         }
2220
2221         ret = 0; /* everything checks out */
2222
2223 out:
2224         if (map)
2225                 munmap(map, mapsize);
2226         return ret;
2227 }