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