Merge branch 'rs/use-copy-array-in-mingw-shell-command-preparation'
[git] / 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 "repository.h"
26 #include "replace-object.h"
27 #include "streaming.h"
28 #include "dir.h"
29 #include "list.h"
30 #include "mergesort.h"
31 #include "quote.h"
32 #include "packfile.h"
33 #include "object-store.h"
34 #include "promisor-remote.h"
35
36 /* The maximum size for an object header. */
37 #define MAX_HEADER_LEN 32
38
39
40 #define EMPTY_TREE_SHA1_BIN_LITERAL \
41          "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
42          "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
43 #define EMPTY_TREE_SHA256_BIN_LITERAL \
44         "\x6e\xf1\x9b\x41\x22\x5c\x53\x69\xf1\xc1" \
45         "\x04\xd4\x5d\x8d\x85\xef\xa9\xb0\x57\xb5" \
46         "\x3b\x14\xb4\xb9\xb9\x39\xdd\x74\xde\xcc" \
47         "\x53\x21"
48
49 #define EMPTY_BLOB_SHA1_BIN_LITERAL \
50         "\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
51         "\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
52 #define EMPTY_BLOB_SHA256_BIN_LITERAL \
53         "\x47\x3a\x0f\x4c\x3b\xe8\xa9\x36\x81\xa2" \
54         "\x67\xe3\xb1\xe9\xa7\xdc\xda\x11\x85\x43" \
55         "\x6f\xe1\x41\xf7\x74\x91\x20\xa3\x03\x72" \
56         "\x18\x13"
57
58 const struct object_id null_oid;
59 static const struct object_id empty_tree_oid = {
60         EMPTY_TREE_SHA1_BIN_LITERAL
61 };
62 static const struct object_id empty_blob_oid = {
63         EMPTY_BLOB_SHA1_BIN_LITERAL
64 };
65 static const struct object_id empty_tree_oid_sha256 = {
66         EMPTY_TREE_SHA256_BIN_LITERAL
67 };
68 static const struct object_id empty_blob_oid_sha256 = {
69         EMPTY_BLOB_SHA256_BIN_LITERAL
70 };
71
72 static void git_hash_sha1_init(git_hash_ctx *ctx)
73 {
74         git_SHA1_Init(&ctx->sha1);
75 }
76
77 static void git_hash_sha1_update(git_hash_ctx *ctx, const void *data, size_t len)
78 {
79         git_SHA1_Update(&ctx->sha1, data, len);
80 }
81
82 static void git_hash_sha1_final(unsigned char *hash, git_hash_ctx *ctx)
83 {
84         git_SHA1_Final(hash, &ctx->sha1);
85 }
86
87
88 static void git_hash_sha256_init(git_hash_ctx *ctx)
89 {
90         git_SHA256_Init(&ctx->sha256);
91 }
92
93 static void git_hash_sha256_update(git_hash_ctx *ctx, const void *data, size_t len)
94 {
95         git_SHA256_Update(&ctx->sha256, data, len);
96 }
97
98 static void git_hash_sha256_final(unsigned char *hash, git_hash_ctx *ctx)
99 {
100         git_SHA256_Final(hash, &ctx->sha256);
101 }
102
103 static void git_hash_unknown_init(git_hash_ctx *ctx)
104 {
105         BUG("trying to init unknown hash");
106 }
107
108 static void git_hash_unknown_update(git_hash_ctx *ctx, const void *data, size_t len)
109 {
110         BUG("trying to update unknown hash");
111 }
112
113 static void git_hash_unknown_final(unsigned char *hash, git_hash_ctx *ctx)
114 {
115         BUG("trying to finalize unknown hash");
116 }
117
118 const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
119         {
120                 NULL,
121                 0x00000000,
122                 0,
123                 0,
124                 0,
125                 git_hash_unknown_init,
126                 git_hash_unknown_update,
127                 git_hash_unknown_final,
128                 NULL,
129                 NULL,
130         },
131         {
132                 "sha1",
133                 /* "sha1", big-endian */
134                 0x73686131,
135                 GIT_SHA1_RAWSZ,
136                 GIT_SHA1_HEXSZ,
137                 GIT_SHA1_BLKSZ,
138                 git_hash_sha1_init,
139                 git_hash_sha1_update,
140                 git_hash_sha1_final,
141                 &empty_tree_oid,
142                 &empty_blob_oid,
143         },
144         {
145                 "sha256",
146                 /* "s256", big-endian */
147                 0x73323536,
148                 GIT_SHA256_RAWSZ,
149                 GIT_SHA256_HEXSZ,
150                 GIT_SHA256_BLKSZ,
151                 git_hash_sha256_init,
152                 git_hash_sha256_update,
153                 git_hash_sha256_final,
154                 &empty_tree_oid_sha256,
155                 &empty_blob_oid_sha256,
156         }
157 };
158
159 const char *empty_tree_oid_hex(void)
160 {
161         static char buf[GIT_MAX_HEXSZ + 1];
162         return oid_to_hex_r(buf, the_hash_algo->empty_tree);
163 }
164
165 const char *empty_blob_oid_hex(void)
166 {
167         static char buf[GIT_MAX_HEXSZ + 1];
168         return oid_to_hex_r(buf, the_hash_algo->empty_blob);
169 }
170
171 int hash_algo_by_name(const char *name)
172 {
173         int i;
174         if (!name)
175                 return GIT_HASH_UNKNOWN;
176         for (i = 1; i < GIT_HASH_NALGOS; i++)
177                 if (!strcmp(name, hash_algos[i].name))
178                         return i;
179         return GIT_HASH_UNKNOWN;
180 }
181
182 int hash_algo_by_id(uint32_t format_id)
183 {
184         int i;
185         for (i = 1; i < GIT_HASH_NALGOS; i++)
186                 if (format_id == hash_algos[i].format_id)
187                         return i;
188         return GIT_HASH_UNKNOWN;
189 }
190
191 int hash_algo_by_length(int len)
192 {
193         int i;
194         for (i = 1; i < GIT_HASH_NALGOS; i++)
195                 if (len == hash_algos[i].rawsz)
196                         return i;
197         return GIT_HASH_UNKNOWN;
198 }
199
200 /*
201  * This is meant to hold a *small* number of objects that you would
202  * want read_object_file() to be able to return, but yet you do not want
203  * to write them into the object store (e.g. a browse-only
204  * application).
205  */
206 static struct cached_object {
207         struct object_id oid;
208         enum object_type type;
209         void *buf;
210         unsigned long size;
211 } *cached_objects;
212 static int cached_object_nr, cached_object_alloc;
213
214 static struct cached_object empty_tree = {
215         { EMPTY_TREE_SHA1_BIN_LITERAL },
216         OBJ_TREE,
217         "",
218         0
219 };
220
221 static struct cached_object *find_cached_object(const struct object_id *oid)
222 {
223         int i;
224         struct cached_object *co = cached_objects;
225
226         for (i = 0; i < cached_object_nr; i++, co++) {
227                 if (oideq(&co->oid, oid))
228                         return co;
229         }
230         if (oideq(oid, the_hash_algo->empty_tree))
231                 return &empty_tree;
232         return NULL;
233 }
234
235
236 static int get_conv_flags(unsigned flags)
237 {
238         if (flags & HASH_RENORMALIZE)
239                 return CONV_EOL_RENORMALIZE;
240         else if (flags & HASH_WRITE_OBJECT)
241                 return global_conv_flags_eol | CONV_WRITE_OBJECT;
242         else
243                 return 0;
244 }
245
246
247 int mkdir_in_gitdir(const char *path)
248 {
249         if (mkdir(path, 0777)) {
250                 int saved_errno = errno;
251                 struct stat st;
252                 struct strbuf sb = STRBUF_INIT;
253
254                 if (errno != EEXIST)
255                         return -1;
256                 /*
257                  * Are we looking at a path in a symlinked worktree
258                  * whose original repository does not yet have it?
259                  * e.g. .git/rr-cache pointing at its original
260                  * repository in which the user hasn't performed any
261                  * conflict resolution yet?
262                  */
263                 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
264                     strbuf_readlink(&sb, path, st.st_size) ||
265                     !is_absolute_path(sb.buf) ||
266                     mkdir(sb.buf, 0777)) {
267                         strbuf_release(&sb);
268                         errno = saved_errno;
269                         return -1;
270                 }
271                 strbuf_release(&sb);
272         }
273         return adjust_shared_perm(path);
274 }
275
276 enum scld_error safe_create_leading_directories(char *path)
277 {
278         char *next_component = path + offset_1st_component(path);
279         enum scld_error ret = SCLD_OK;
280
281         while (ret == SCLD_OK && next_component) {
282                 struct stat st;
283                 char *slash = next_component, slash_character;
284
285                 while (*slash && !is_dir_sep(*slash))
286                         slash++;
287
288                 if (!*slash)
289                         break;
290
291                 next_component = slash + 1;
292                 while (is_dir_sep(*next_component))
293                         next_component++;
294                 if (!*next_component)
295                         break;
296
297                 slash_character = *slash;
298                 *slash = '\0';
299                 if (!stat(path, &st)) {
300                         /* path exists */
301                         if (!S_ISDIR(st.st_mode)) {
302                                 errno = ENOTDIR;
303                                 ret = SCLD_EXISTS;
304                         }
305                 } else if (mkdir(path, 0777)) {
306                         if (errno == EEXIST &&
307                             !stat(path, &st) && S_ISDIR(st.st_mode))
308                                 ; /* somebody created it since we checked */
309                         else if (errno == ENOENT)
310                                 /*
311                                  * Either mkdir() failed because
312                                  * somebody just pruned the containing
313                                  * directory, or stat() failed because
314                                  * the file that was in our way was
315                                  * just removed.  Either way, inform
316                                  * the caller that it might be worth
317                                  * trying again:
318                                  */
319                                 ret = SCLD_VANISHED;
320                         else
321                                 ret = SCLD_FAILED;
322                 } else if (adjust_shared_perm(path)) {
323                         ret = SCLD_PERMS;
324                 }
325                 *slash = slash_character;
326         }
327         return ret;
328 }
329
330 enum scld_error safe_create_leading_directories_const(const char *path)
331 {
332         int save_errno;
333         /* path points to cache entries, so xstrdup before messing with it */
334         char *buf = xstrdup(path);
335         enum scld_error result = safe_create_leading_directories(buf);
336
337         save_errno = errno;
338         free(buf);
339         errno = save_errno;
340         return result;
341 }
342
343 int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
344 {
345         /*
346          * The number of times we will try to remove empty directories
347          * in the way of path. This is only 1 because if another
348          * process is racily creating directories that conflict with
349          * us, we don't want to fight against them.
350          */
351         int remove_directories_remaining = 1;
352
353         /*
354          * The number of times that we will try to create the
355          * directories containing path. We are willing to attempt this
356          * more than once, because another process could be trying to
357          * clean up empty directories at the same time as we are
358          * trying to create them.
359          */
360         int create_directories_remaining = 3;
361
362         /* A scratch copy of path, filled lazily if we need it: */
363         struct strbuf path_copy = STRBUF_INIT;
364
365         int ret, save_errno;
366
367         /* Sanity check: */
368         assert(*path);
369
370 retry_fn:
371         ret = fn(path, cb);
372         save_errno = errno;
373         if (!ret)
374                 goto out;
375
376         if (errno == EISDIR && remove_directories_remaining-- > 0) {
377                 /*
378                  * A directory is in the way. Maybe it is empty; try
379                  * to remove it:
380                  */
381                 if (!path_copy.len)
382                         strbuf_addstr(&path_copy, path);
383
384                 if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
385                         goto retry_fn;
386         } else if (errno == ENOENT && create_directories_remaining-- > 0) {
387                 /*
388                  * Maybe the containing directory didn't exist, or
389                  * maybe it was just deleted by a process that is
390                  * racing with us to clean up empty directories. Try
391                  * to create it:
392                  */
393                 enum scld_error scld_result;
394
395                 if (!path_copy.len)
396                         strbuf_addstr(&path_copy, path);
397
398                 do {
399                         scld_result = safe_create_leading_directories(path_copy.buf);
400                         if (scld_result == SCLD_OK)
401                                 goto retry_fn;
402                 } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
403         }
404
405 out:
406         strbuf_release(&path_copy);
407         errno = save_errno;
408         return ret;
409 }
410
411 static void fill_loose_path(struct strbuf *buf, const struct object_id *oid)
412 {
413         int i;
414         for (i = 0; i < the_hash_algo->rawsz; i++) {
415                 static char hex[] = "0123456789abcdef";
416                 unsigned int val = oid->hash[i];
417                 strbuf_addch(buf, hex[val >> 4]);
418                 strbuf_addch(buf, hex[val & 0xf]);
419                 if (!i)
420                         strbuf_addch(buf, '/');
421         }
422 }
423
424 static const char *odb_loose_path(struct object_directory *odb,
425                                   struct strbuf *buf,
426                                   const struct object_id *oid)
427 {
428         strbuf_reset(buf);
429         strbuf_addstr(buf, odb->path);
430         strbuf_addch(buf, '/');
431         fill_loose_path(buf, oid);
432         return buf->buf;
433 }
434
435 const char *loose_object_path(struct repository *r, struct strbuf *buf,
436                               const struct object_id *oid)
437 {
438         return odb_loose_path(r->objects->odb, buf, oid);
439 }
440
441 /*
442  * Return non-zero iff the path is usable as an alternate object database.
443  */
444 static int alt_odb_usable(struct raw_object_store *o,
445                           struct strbuf *path,
446                           const char *normalized_objdir)
447 {
448         struct object_directory *odb;
449
450         /* Detect cases where alternate disappeared */
451         if (!is_directory(path->buf)) {
452                 error(_("object directory %s does not exist; "
453                         "check .git/objects/info/alternates"),
454                       path->buf);
455                 return 0;
456         }
457
458         /*
459          * Prevent the common mistake of listing the same
460          * thing twice, or object directory itself.
461          */
462         for (odb = o->odb; odb; odb = odb->next) {
463                 if (!fspathcmp(path->buf, odb->path))
464                         return 0;
465         }
466         if (!fspathcmp(path->buf, normalized_objdir))
467                 return 0;
468
469         return 1;
470 }
471
472 /*
473  * Prepare alternate object database registry.
474  *
475  * The variable alt_odb_list points at the list of struct
476  * object_directory.  The elements on this list come from
477  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
478  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
479  * whose contents is similar to that environment variable but can be
480  * LF separated.  Its base points at a statically allocated buffer that
481  * contains "/the/directory/corresponding/to/.git/objects/...", while
482  * its name points just after the slash at the end of ".git/objects/"
483  * in the example above, and has enough space to hold 40-byte hex
484  * SHA1, an extra slash for the first level indirection, and the
485  * terminating NUL.
486  */
487 static void read_info_alternates(struct repository *r,
488                                  const char *relative_base,
489                                  int depth);
490 static int link_alt_odb_entry(struct repository *r, const char *entry,
491         const char *relative_base, int depth, const char *normalized_objdir)
492 {
493         struct object_directory *ent;
494         struct strbuf pathbuf = STRBUF_INIT;
495
496         if (!is_absolute_path(entry) && relative_base) {
497                 strbuf_realpath(&pathbuf, relative_base, 1);
498                 strbuf_addch(&pathbuf, '/');
499         }
500         strbuf_addstr(&pathbuf, entry);
501
502         if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
503                 error(_("unable to normalize alternate object path: %s"),
504                       pathbuf.buf);
505                 strbuf_release(&pathbuf);
506                 return -1;
507         }
508
509         /*
510          * The trailing slash after the directory name is given by
511          * this function at the end. Remove duplicates.
512          */
513         while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
514                 strbuf_setlen(&pathbuf, pathbuf.len - 1);
515
516         if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir)) {
517                 strbuf_release(&pathbuf);
518                 return -1;
519         }
520
521         ent = xcalloc(1, sizeof(*ent));
522         ent->path = xstrdup(pathbuf.buf);
523
524         /* add the alternate entry */
525         *r->objects->odb_tail = ent;
526         r->objects->odb_tail = &(ent->next);
527         ent->next = NULL;
528
529         /* recursively add alternates */
530         read_info_alternates(r, pathbuf.buf, depth + 1);
531
532         strbuf_release(&pathbuf);
533         return 0;
534 }
535
536 static const char *parse_alt_odb_entry(const char *string,
537                                        int sep,
538                                        struct strbuf *out)
539 {
540         const char *end;
541
542         strbuf_reset(out);
543
544         if (*string == '#') {
545                 /* comment; consume up to next separator */
546                 end = strchrnul(string, sep);
547         } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
548                 /*
549                  * quoted path; unquote_c_style has copied the
550                  * data for us and set "end". Broken quoting (e.g.,
551                  * an entry that doesn't end with a quote) falls
552                  * back to the unquoted case below.
553                  */
554         } else {
555                 /* normal, unquoted path */
556                 end = strchrnul(string, sep);
557                 strbuf_add(out, string, end - string);
558         }
559
560         if (*end)
561                 end++;
562         return end;
563 }
564
565 static void link_alt_odb_entries(struct repository *r, const char *alt,
566                                  int sep, const char *relative_base, int depth)
567 {
568         struct strbuf objdirbuf = STRBUF_INIT;
569         struct strbuf entry = STRBUF_INIT;
570
571         if (!alt || !*alt)
572                 return;
573
574         if (depth > 5) {
575                 error(_("%s: ignoring alternate object stores, nesting too deep"),
576                                 relative_base);
577                 return;
578         }
579
580         strbuf_add_absolute_path(&objdirbuf, r->objects->odb->path);
581         if (strbuf_normalize_path(&objdirbuf) < 0)
582                 die(_("unable to normalize object directory: %s"),
583                     objdirbuf.buf);
584
585         while (*alt) {
586                 alt = parse_alt_odb_entry(alt, sep, &entry);
587                 if (!entry.len)
588                         continue;
589                 link_alt_odb_entry(r, entry.buf,
590                                    relative_base, depth, objdirbuf.buf);
591         }
592         strbuf_release(&entry);
593         strbuf_release(&objdirbuf);
594 }
595
596 static void read_info_alternates(struct repository *r,
597                                  const char *relative_base,
598                                  int depth)
599 {
600         char *path;
601         struct strbuf buf = STRBUF_INIT;
602
603         path = xstrfmt("%s/info/alternates", relative_base);
604         if (strbuf_read_file(&buf, path, 1024) < 0) {
605                 warn_on_fopen_errors(path);
606                 free(path);
607                 return;
608         }
609
610         link_alt_odb_entries(r, buf.buf, '\n', relative_base, depth);
611         strbuf_release(&buf);
612         free(path);
613 }
614
615 void add_to_alternates_file(const char *reference)
616 {
617         struct lock_file lock = LOCK_INIT;
618         char *alts = git_pathdup("objects/info/alternates");
619         FILE *in, *out;
620         int found = 0;
621
622         hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
623         out = fdopen_lock_file(&lock, "w");
624         if (!out)
625                 die_errno(_("unable to fdopen alternates lockfile"));
626
627         in = fopen(alts, "r");
628         if (in) {
629                 struct strbuf line = STRBUF_INIT;
630
631                 while (strbuf_getline(&line, in) != EOF) {
632                         if (!strcmp(reference, line.buf)) {
633                                 found = 1;
634                                 break;
635                         }
636                         fprintf_or_die(out, "%s\n", line.buf);
637                 }
638
639                 strbuf_release(&line);
640                 fclose(in);
641         }
642         else if (errno != ENOENT)
643                 die_errno(_("unable to read alternates file"));
644
645         if (found) {
646                 rollback_lock_file(&lock);
647         } else {
648                 fprintf_or_die(out, "%s\n", reference);
649                 if (commit_lock_file(&lock))
650                         die_errno(_("unable to move new alternates file into place"));
651                 if (the_repository->objects->loaded_alternates)
652                         link_alt_odb_entries(the_repository, reference,
653                                              '\n', NULL, 0);
654         }
655         free(alts);
656 }
657
658 void add_to_alternates_memory(const char *reference)
659 {
660         /*
661          * Make sure alternates are initialized, or else our entry may be
662          * overwritten when they are.
663          */
664         prepare_alt_odb(the_repository);
665
666         link_alt_odb_entries(the_repository, reference,
667                              '\n', NULL, 0);
668 }
669
670 /*
671  * Compute the exact path an alternate is at and returns it. In case of
672  * error NULL is returned and the human readable error is added to `err`
673  * `path` may be relative and should point to $GIT_DIR.
674  * `err` must not be null.
675  */
676 char *compute_alternate_path(const char *path, struct strbuf *err)
677 {
678         char *ref_git = NULL;
679         const char *repo, *ref_git_s;
680         int seen_error = 0;
681
682         ref_git_s = real_path_if_valid(path);
683         if (!ref_git_s) {
684                 seen_error = 1;
685                 strbuf_addf(err, _("path '%s' does not exist"), path);
686                 goto out;
687         } else
688                 /*
689                  * Beware: read_gitfile(), real_path() and mkpath()
690                  * return static buffer
691                  */
692                 ref_git = xstrdup(ref_git_s);
693
694         repo = read_gitfile(ref_git);
695         if (!repo)
696                 repo = read_gitfile(mkpath("%s/.git", ref_git));
697         if (repo) {
698                 free(ref_git);
699                 ref_git = xstrdup(repo);
700         }
701
702         if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
703                 char *ref_git_git = mkpathdup("%s/.git", ref_git);
704                 free(ref_git);
705                 ref_git = ref_git_git;
706         } else if (!is_directory(mkpath("%s/objects", ref_git))) {
707                 struct strbuf sb = STRBUF_INIT;
708                 seen_error = 1;
709                 if (get_common_dir(&sb, ref_git)) {
710                         strbuf_addf(err,
711                                     _("reference repository '%s' as a linked "
712                                       "checkout is not supported yet."),
713                                     path);
714                         goto out;
715                 }
716
717                 strbuf_addf(err, _("reference repository '%s' is not a "
718                                         "local repository."), path);
719                 goto out;
720         }
721
722         if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
723                 strbuf_addf(err, _("reference repository '%s' is shallow"),
724                             path);
725                 seen_error = 1;
726                 goto out;
727         }
728
729         if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
730                 strbuf_addf(err,
731                             _("reference repository '%s' is grafted"),
732                             path);
733                 seen_error = 1;
734                 goto out;
735         }
736
737 out:
738         if (seen_error) {
739                 FREE_AND_NULL(ref_git);
740         }
741
742         return ref_git;
743 }
744
745 static void fill_alternate_refs_command(struct child_process *cmd,
746                                         const char *repo_path)
747 {
748         const char *value;
749
750         if (!git_config_get_value("core.alternateRefsCommand", &value)) {
751                 cmd->use_shell = 1;
752
753                 argv_array_push(&cmd->args, value);
754                 argv_array_push(&cmd->args, repo_path);
755         } else {
756                 cmd->git_cmd = 1;
757
758                 argv_array_pushf(&cmd->args, "--git-dir=%s", repo_path);
759                 argv_array_push(&cmd->args, "for-each-ref");
760                 argv_array_push(&cmd->args, "--format=%(objectname)");
761
762                 if (!git_config_get_value("core.alternateRefsPrefixes", &value)) {
763                         argv_array_push(&cmd->args, "--");
764                         argv_array_split(&cmd->args, value);
765                 }
766         }
767
768         cmd->env = local_repo_env;
769         cmd->out = -1;
770 }
771
772 static void read_alternate_refs(const char *path,
773                                 alternate_ref_fn *cb,
774                                 void *data)
775 {
776         struct child_process cmd = CHILD_PROCESS_INIT;
777         struct strbuf line = STRBUF_INIT;
778         FILE *fh;
779
780         fill_alternate_refs_command(&cmd, path);
781
782         if (start_command(&cmd))
783                 return;
784
785         fh = xfdopen(cmd.out, "r");
786         while (strbuf_getline_lf(&line, fh) != EOF) {
787                 struct object_id oid;
788                 const char *p;
789
790                 if (parse_oid_hex(line.buf, &oid, &p) || *p) {
791                         warning(_("invalid line while parsing alternate refs: %s"),
792                                 line.buf);
793                         break;
794                 }
795
796                 cb(&oid, data);
797         }
798
799         fclose(fh);
800         finish_command(&cmd);
801         strbuf_release(&line);
802 }
803
804 struct alternate_refs_data {
805         alternate_ref_fn *fn;
806         void *data;
807 };
808
809 static int refs_from_alternate_cb(struct object_directory *e,
810                                   void *data)
811 {
812         struct strbuf path = STRBUF_INIT;
813         size_t base_len;
814         struct alternate_refs_data *cb = data;
815
816         if (!strbuf_realpath(&path, e->path, 0))
817                 goto out;
818         if (!strbuf_strip_suffix(&path, "/objects"))
819                 goto out;
820         base_len = path.len;
821
822         /* Is this a git repository with refs? */
823         strbuf_addstr(&path, "/refs");
824         if (!is_directory(path.buf))
825                 goto out;
826         strbuf_setlen(&path, base_len);
827
828         read_alternate_refs(path.buf, cb->fn, cb->data);
829
830 out:
831         strbuf_release(&path);
832         return 0;
833 }
834
835 void for_each_alternate_ref(alternate_ref_fn fn, void *data)
836 {
837         struct alternate_refs_data cb;
838         cb.fn = fn;
839         cb.data = data;
840         foreach_alt_odb(refs_from_alternate_cb, &cb);
841 }
842
843 int foreach_alt_odb(alt_odb_fn fn, void *cb)
844 {
845         struct object_directory *ent;
846         int r = 0;
847
848         prepare_alt_odb(the_repository);
849         for (ent = the_repository->objects->odb->next; ent; ent = ent->next) {
850                 r = fn(ent, cb);
851                 if (r)
852                         break;
853         }
854         return r;
855 }
856
857 void prepare_alt_odb(struct repository *r)
858 {
859         if (r->objects->loaded_alternates)
860                 return;
861
862         link_alt_odb_entries(r, r->objects->alternate_db, PATH_SEP, NULL, 0);
863
864         read_info_alternates(r, r->objects->odb->path, 0);
865         r->objects->loaded_alternates = 1;
866 }
867
868 /* Returns 1 if we have successfully freshened the file, 0 otherwise. */
869 static int freshen_file(const char *fn)
870 {
871         struct utimbuf t;
872         t.actime = t.modtime = time(NULL);
873         return !utime(fn, &t);
874 }
875
876 /*
877  * All of the check_and_freshen functions return 1 if the file exists and was
878  * freshened (if freshening was requested), 0 otherwise. If they return
879  * 0, you should not assume that it is safe to skip a write of the object (it
880  * either does not exist on disk, or has a stale mtime and may be subject to
881  * pruning).
882  */
883 int check_and_freshen_file(const char *fn, int freshen)
884 {
885         if (access(fn, F_OK))
886                 return 0;
887         if (freshen && !freshen_file(fn))
888                 return 0;
889         return 1;
890 }
891
892 static int check_and_freshen_odb(struct object_directory *odb,
893                                  const struct object_id *oid,
894                                  int freshen)
895 {
896         static struct strbuf path = STRBUF_INIT;
897         odb_loose_path(odb, &path, oid);
898         return check_and_freshen_file(path.buf, freshen);
899 }
900
901 static int check_and_freshen_local(const struct object_id *oid, int freshen)
902 {
903         return check_and_freshen_odb(the_repository->objects->odb, oid, freshen);
904 }
905
906 static int check_and_freshen_nonlocal(const struct object_id *oid, int freshen)
907 {
908         struct object_directory *odb;
909
910         prepare_alt_odb(the_repository);
911         for (odb = the_repository->objects->odb->next; odb; odb = odb->next) {
912                 if (check_and_freshen_odb(odb, oid, freshen))
913                         return 1;
914         }
915         return 0;
916 }
917
918 static int check_and_freshen(const struct object_id *oid, int freshen)
919 {
920         return check_and_freshen_local(oid, freshen) ||
921                check_and_freshen_nonlocal(oid, freshen);
922 }
923
924 int has_loose_object_nonlocal(const struct object_id *oid)
925 {
926         return check_and_freshen_nonlocal(oid, 0);
927 }
928
929 static int has_loose_object(const struct object_id *oid)
930 {
931         return check_and_freshen(oid, 0);
932 }
933
934 static void mmap_limit_check(size_t length)
935 {
936         static size_t limit = 0;
937         if (!limit) {
938                 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
939                 if (!limit)
940                         limit = SIZE_MAX;
941         }
942         if (length > limit)
943                 die(_("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX),
944                     (uintmax_t)length, (uintmax_t)limit);
945 }
946
947 void *xmmap_gently(void *start, size_t length,
948                   int prot, int flags, int fd, off_t offset)
949 {
950         void *ret;
951
952         mmap_limit_check(length);
953         ret = mmap(start, length, prot, flags, fd, offset);
954         if (ret == MAP_FAILED && !length)
955                 ret = NULL;
956         return ret;
957 }
958
959 void *xmmap(void *start, size_t length,
960         int prot, int flags, int fd, off_t offset)
961 {
962         void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
963         if (ret == MAP_FAILED)
964                 die_errno(_("mmap failed"));
965         return ret;
966 }
967
968 /*
969  * With an in-core object data in "map", rehash it to make sure the
970  * object name actually matches "oid" to detect object corruption.
971  * With "map" == NULL, try reading the object named with "oid" using
972  * the streaming interface and rehash it to do the same.
973  */
974 int check_object_signature(const struct object_id *oid, void *map,
975                            unsigned long size, const char *type)
976 {
977         struct object_id real_oid;
978         enum object_type obj_type;
979         struct git_istream *st;
980         git_hash_ctx c;
981         char hdr[MAX_HEADER_LEN];
982         int hdrlen;
983
984         if (map) {
985                 hash_object_file(map, size, type, &real_oid);
986                 return !oideq(oid, &real_oid) ? -1 : 0;
987         }
988
989         st = open_istream(oid, &obj_type, &size, NULL);
990         if (!st)
991                 return -1;
992
993         /* Generate the header */
994         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(obj_type), (uintmax_t)size) + 1;
995
996         /* Sha1.. */
997         the_hash_algo->init_fn(&c);
998         the_hash_algo->update_fn(&c, hdr, hdrlen);
999         for (;;) {
1000                 char buf[1024 * 16];
1001                 ssize_t readlen = read_istream(st, buf, sizeof(buf));
1002
1003                 if (readlen < 0) {
1004                         close_istream(st);
1005                         return -1;
1006                 }
1007                 if (!readlen)
1008                         break;
1009                 the_hash_algo->update_fn(&c, buf, readlen);
1010         }
1011         the_hash_algo->final_fn(real_oid.hash, &c);
1012         close_istream(st);
1013         return !oideq(oid, &real_oid) ? -1 : 0;
1014 }
1015
1016 int git_open_cloexec(const char *name, int flags)
1017 {
1018         int fd;
1019         static int o_cloexec = O_CLOEXEC;
1020
1021         fd = open(name, flags | o_cloexec);
1022         if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
1023                 /* Try again w/o O_CLOEXEC: the kernel might not support it */
1024                 o_cloexec &= ~O_CLOEXEC;
1025                 fd = open(name, flags | o_cloexec);
1026         }
1027
1028 #if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
1029         {
1030                 static int fd_cloexec = FD_CLOEXEC;
1031
1032                 if (!o_cloexec && 0 <= fd && fd_cloexec) {
1033                         /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
1034                         int flags = fcntl(fd, F_GETFD);
1035                         if (fcntl(fd, F_SETFD, flags | fd_cloexec))
1036                                 fd_cloexec = 0;
1037                 }
1038         }
1039 #endif
1040         return fd;
1041 }
1042
1043 /*
1044  * Find "oid" as a loose object in the local repository or in an alternate.
1045  * Returns 0 on success, negative on failure.
1046  *
1047  * The "path" out-parameter will give the path of the object we found (if any).
1048  * Note that it may point to static storage and is only valid until another
1049  * call to stat_loose_object().
1050  */
1051 static int stat_loose_object(struct repository *r, const struct object_id *oid,
1052                              struct stat *st, const char **path)
1053 {
1054         struct object_directory *odb;
1055         static struct strbuf buf = STRBUF_INIT;
1056
1057         prepare_alt_odb(r);
1058         for (odb = r->objects->odb; odb; odb = odb->next) {
1059                 *path = odb_loose_path(odb, &buf, oid);
1060                 if (!lstat(*path, st))
1061                         return 0;
1062         }
1063
1064         return -1;
1065 }
1066
1067 /*
1068  * Like stat_loose_object(), but actually open the object and return the
1069  * descriptor. See the caveats on the "path" parameter above.
1070  */
1071 static int open_loose_object(struct repository *r,
1072                              const struct object_id *oid, const char **path)
1073 {
1074         int fd;
1075         struct object_directory *odb;
1076         int most_interesting_errno = ENOENT;
1077         static struct strbuf buf = STRBUF_INIT;
1078
1079         prepare_alt_odb(r);
1080         for (odb = r->objects->odb; odb; odb = odb->next) {
1081                 *path = odb_loose_path(odb, &buf, oid);
1082                 fd = git_open(*path);
1083                 if (fd >= 0)
1084                         return fd;
1085
1086                 if (most_interesting_errno == ENOENT)
1087                         most_interesting_errno = errno;
1088         }
1089         errno = most_interesting_errno;
1090         return -1;
1091 }
1092
1093 static int quick_has_loose(struct repository *r,
1094                            const struct object_id *oid)
1095 {
1096         struct object_directory *odb;
1097
1098         prepare_alt_odb(r);
1099         for (odb = r->objects->odb; odb; odb = odb->next) {
1100                 if (oid_array_lookup(odb_loose_cache(odb, oid), oid) >= 0)
1101                         return 1;
1102         }
1103         return 0;
1104 }
1105
1106 /*
1107  * Map the loose object at "path" if it is not NULL, or the path found by
1108  * searching for a loose object named "oid".
1109  */
1110 static void *map_loose_object_1(struct repository *r, const char *path,
1111                              const struct object_id *oid, unsigned long *size)
1112 {
1113         void *map;
1114         int fd;
1115
1116         if (path)
1117                 fd = git_open(path);
1118         else
1119                 fd = open_loose_object(r, oid, &path);
1120         map = NULL;
1121         if (fd >= 0) {
1122                 struct stat st;
1123
1124                 if (!fstat(fd, &st)) {
1125                         *size = xsize_t(st.st_size);
1126                         if (!*size) {
1127                                 /* mmap() is forbidden on empty files */
1128                                 error(_("object file %s is empty"), path);
1129                                 close(fd);
1130                                 return NULL;
1131                         }
1132                         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1133                 }
1134                 close(fd);
1135         }
1136         return map;
1137 }
1138
1139 void *map_loose_object(struct repository *r,
1140                        const struct object_id *oid,
1141                        unsigned long *size)
1142 {
1143         return map_loose_object_1(r, NULL, oid, size);
1144 }
1145
1146 static int unpack_loose_short_header(git_zstream *stream,
1147                                      unsigned char *map, unsigned long mapsize,
1148                                      void *buffer, unsigned long bufsiz)
1149 {
1150         /* Get the data stream */
1151         memset(stream, 0, sizeof(*stream));
1152         stream->next_in = map;
1153         stream->avail_in = mapsize;
1154         stream->next_out = buffer;
1155         stream->avail_out = bufsiz;
1156
1157         git_inflate_init(stream);
1158         return git_inflate(stream, 0);
1159 }
1160
1161 int unpack_loose_header(git_zstream *stream,
1162                         unsigned char *map, unsigned long mapsize,
1163                         void *buffer, unsigned long bufsiz)
1164 {
1165         int status = unpack_loose_short_header(stream, map, mapsize,
1166                                                buffer, bufsiz);
1167
1168         if (status < Z_OK)
1169                 return status;
1170
1171         /* Make sure we have the terminating NUL */
1172         if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1173                 return -1;
1174         return 0;
1175 }
1176
1177 static int unpack_loose_header_to_strbuf(git_zstream *stream, unsigned char *map,
1178                                          unsigned long mapsize, void *buffer,
1179                                          unsigned long bufsiz, struct strbuf *header)
1180 {
1181         int status;
1182
1183         status = unpack_loose_short_header(stream, map, mapsize, buffer, bufsiz);
1184         if (status < Z_OK)
1185                 return -1;
1186
1187         /*
1188          * Check if entire header is unpacked in the first iteration.
1189          */
1190         if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1191                 return 0;
1192
1193         /*
1194          * buffer[0..bufsiz] was not large enough.  Copy the partial
1195          * result out to header, and then append the result of further
1196          * reading the stream.
1197          */
1198         strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1199         stream->next_out = buffer;
1200         stream->avail_out = bufsiz;
1201
1202         do {
1203                 status = git_inflate(stream, 0);
1204                 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1205                 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1206                         return 0;
1207                 stream->next_out = buffer;
1208                 stream->avail_out = bufsiz;
1209         } while (status != Z_STREAM_END);
1210         return -1;
1211 }
1212
1213 static void *unpack_loose_rest(git_zstream *stream,
1214                                void *buffer, unsigned long size,
1215                                const struct object_id *oid)
1216 {
1217         int bytes = strlen(buffer) + 1;
1218         unsigned char *buf = xmallocz(size);
1219         unsigned long n;
1220         int status = Z_OK;
1221
1222         n = stream->total_out - bytes;
1223         if (n > size)
1224                 n = size;
1225         memcpy(buf, (char *) buffer + bytes, n);
1226         bytes = n;
1227         if (bytes <= size) {
1228                 /*
1229                  * The above condition must be (bytes <= size), not
1230                  * (bytes < size).  In other words, even though we
1231                  * expect no more output and set avail_out to zero,
1232                  * the input zlib stream may have bytes that express
1233                  * "this concludes the stream", and we *do* want to
1234                  * eat that input.
1235                  *
1236                  * Otherwise we would not be able to test that we
1237                  * consumed all the input to reach the expected size;
1238                  * we also want to check that zlib tells us that all
1239                  * went well with status == Z_STREAM_END at the end.
1240                  */
1241                 stream->next_out = buf + bytes;
1242                 stream->avail_out = size - bytes;
1243                 while (status == Z_OK)
1244                         status = git_inflate(stream, Z_FINISH);
1245         }
1246         if (status == Z_STREAM_END && !stream->avail_in) {
1247                 git_inflate_end(stream);
1248                 return buf;
1249         }
1250
1251         if (status < 0)
1252                 error(_("corrupt loose object '%s'"), oid_to_hex(oid));
1253         else if (stream->avail_in)
1254                 error(_("garbage at end of loose object '%s'"),
1255                       oid_to_hex(oid));
1256         free(buf);
1257         return NULL;
1258 }
1259
1260 /*
1261  * We used to just use "sscanf()", but that's actually way
1262  * too permissive for what we want to check. So do an anal
1263  * object header parse by hand.
1264  */
1265 static int parse_loose_header_extended(const char *hdr, struct object_info *oi,
1266                                        unsigned int flags)
1267 {
1268         const char *type_buf = hdr;
1269         unsigned long size;
1270         int type, type_len = 0;
1271
1272         /*
1273          * The type can be of any size but is followed by
1274          * a space.
1275          */
1276         for (;;) {
1277                 char c = *hdr++;
1278                 if (!c)
1279                         return -1;
1280                 if (c == ' ')
1281                         break;
1282                 type_len++;
1283         }
1284
1285         type = type_from_string_gently(type_buf, type_len, 1);
1286         if (oi->type_name)
1287                 strbuf_add(oi->type_name, type_buf, type_len);
1288         /*
1289          * Set type to 0 if its an unknown object and
1290          * we're obtaining the type using '--allow-unknown-type'
1291          * option.
1292          */
1293         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1294                 type = 0;
1295         else if (type < 0)
1296                 die(_("invalid object type"));
1297         if (oi->typep)
1298                 *oi->typep = type;
1299
1300         /*
1301          * The length must follow immediately, and be in canonical
1302          * decimal format (ie "010" is not valid).
1303          */
1304         size = *hdr++ - '0';
1305         if (size > 9)
1306                 return -1;
1307         if (size) {
1308                 for (;;) {
1309                         unsigned long c = *hdr - '0';
1310                         if (c > 9)
1311                                 break;
1312                         hdr++;
1313                         size = size * 10 + c;
1314                 }
1315         }
1316
1317         if (oi->sizep)
1318                 *oi->sizep = size;
1319
1320         /*
1321          * The length must be followed by a zero byte
1322          */
1323         return *hdr ? -1 : type;
1324 }
1325
1326 int parse_loose_header(const char *hdr, unsigned long *sizep)
1327 {
1328         struct object_info oi = OBJECT_INFO_INIT;
1329
1330         oi.sizep = sizep;
1331         return parse_loose_header_extended(hdr, &oi, 0);
1332 }
1333
1334 static int loose_object_info(struct repository *r,
1335                              const struct object_id *oid,
1336                              struct object_info *oi, int flags)
1337 {
1338         int status = 0;
1339         unsigned long mapsize;
1340         void *map;
1341         git_zstream stream;
1342         char hdr[MAX_HEADER_LEN];
1343         struct strbuf hdrbuf = STRBUF_INIT;
1344         unsigned long size_scratch;
1345
1346         if (oi->delta_base_sha1)
1347                 hashclr(oi->delta_base_sha1);
1348
1349         /*
1350          * If we don't care about type or size, then we don't
1351          * need to look inside the object at all. Note that we
1352          * do not optimize out the stat call, even if the
1353          * caller doesn't care about the disk-size, since our
1354          * return value implicitly indicates whether the
1355          * object even exists.
1356          */
1357         if (!oi->typep && !oi->type_name && !oi->sizep && !oi->contentp) {
1358                 const char *path;
1359                 struct stat st;
1360                 if (!oi->disk_sizep && (flags & OBJECT_INFO_QUICK))
1361                         return quick_has_loose(r, oid) ? 0 : -1;
1362                 if (stat_loose_object(r, oid, &st, &path) < 0)
1363                         return -1;
1364                 if (oi->disk_sizep)
1365                         *oi->disk_sizep = st.st_size;
1366                 return 0;
1367         }
1368
1369         map = map_loose_object(r, oid, &mapsize);
1370         if (!map)
1371                 return -1;
1372
1373         if (!oi->sizep)
1374                 oi->sizep = &size_scratch;
1375
1376         if (oi->disk_sizep)
1377                 *oi->disk_sizep = mapsize;
1378         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1379                 if (unpack_loose_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1380                         status = error(_("unable to unpack %s header with --allow-unknown-type"),
1381                                        oid_to_hex(oid));
1382         } else if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1383                 status = error(_("unable to unpack %s header"),
1384                                oid_to_hex(oid));
1385         if (status < 0)
1386                 ; /* Do nothing */
1387         else if (hdrbuf.len) {
1388                 if ((status = parse_loose_header_extended(hdrbuf.buf, oi, flags)) < 0)
1389                         status = error(_("unable to parse %s header with --allow-unknown-type"),
1390                                        oid_to_hex(oid));
1391         } else if ((status = parse_loose_header_extended(hdr, oi, flags)) < 0)
1392                 status = error(_("unable to parse %s header"), oid_to_hex(oid));
1393
1394         if (status >= 0 && oi->contentp) {
1395                 *oi->contentp = unpack_loose_rest(&stream, hdr,
1396                                                   *oi->sizep, oid);
1397                 if (!*oi->contentp) {
1398                         git_inflate_end(&stream);
1399                         status = -1;
1400                 }
1401         } else
1402                 git_inflate_end(&stream);
1403
1404         munmap(map, mapsize);
1405         if (status && oi->typep)
1406                 *oi->typep = status;
1407         if (oi->sizep == &size_scratch)
1408                 oi->sizep = NULL;
1409         strbuf_release(&hdrbuf);
1410         oi->whence = OI_LOOSE;
1411         return (status < 0) ? status : 0;
1412 }
1413
1414 int fetch_if_missing = 1;
1415
1416 int oid_object_info_extended(struct repository *r, const struct object_id *oid,
1417                              struct object_info *oi, unsigned flags)
1418 {
1419         static struct object_info blank_oi = OBJECT_INFO_INIT;
1420         struct pack_entry e;
1421         int rtype;
1422         const struct object_id *real = oid;
1423         int already_retried = 0;
1424
1425         if (flags & OBJECT_INFO_LOOKUP_REPLACE)
1426                 real = lookup_replace_object(r, oid);
1427
1428         if (is_null_oid(real))
1429                 return -1;
1430
1431         if (!oi)
1432                 oi = &blank_oi;
1433
1434         if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1435                 struct cached_object *co = find_cached_object(real);
1436                 if (co) {
1437                         if (oi->typep)
1438                                 *(oi->typep) = co->type;
1439                         if (oi->sizep)
1440                                 *(oi->sizep) = co->size;
1441                         if (oi->disk_sizep)
1442                                 *(oi->disk_sizep) = 0;
1443                         if (oi->delta_base_sha1)
1444                                 hashclr(oi->delta_base_sha1);
1445                         if (oi->type_name)
1446                                 strbuf_addstr(oi->type_name, type_name(co->type));
1447                         if (oi->contentp)
1448                                 *oi->contentp = xmemdupz(co->buf, co->size);
1449                         oi->whence = OI_CACHED;
1450                         return 0;
1451                 }
1452         }
1453
1454         while (1) {
1455                 if (find_pack_entry(r, real, &e))
1456                         break;
1457
1458                 if (flags & OBJECT_INFO_IGNORE_LOOSE)
1459                         return -1;
1460
1461                 /* Most likely it's a loose object. */
1462                 if (!loose_object_info(r, real, oi, flags))
1463                         return 0;
1464
1465                 /* Not a loose object; someone else may have just packed it. */
1466                 if (!(flags & OBJECT_INFO_QUICK)) {
1467                         reprepare_packed_git(r);
1468                         if (find_pack_entry(r, real, &e))
1469                                 break;
1470                 }
1471
1472                 /* Check if it is a missing object */
1473                 if (fetch_if_missing && has_promisor_remote() &&
1474                     !already_retried && r == the_repository &&
1475                     !(flags & OBJECT_INFO_SKIP_FETCH_OBJECT)) {
1476                         /*
1477                          * TODO Investigate checking promisor_remote_get_direct()
1478                          * TODO return value and stopping on error here.
1479                          * TODO Pass a repository struct through
1480                          * promisor_remote_get_direct(), such that arbitrary
1481                          * repositories work.
1482                          */
1483                         promisor_remote_get_direct(r, real, 1);
1484                         already_retried = 1;
1485                         continue;
1486                 }
1487
1488                 return -1;
1489         }
1490
1491         if (oi == &blank_oi)
1492                 /*
1493                  * We know that the caller doesn't actually need the
1494                  * information below, so return early.
1495                  */
1496                 return 0;
1497         rtype = packed_object_info(r, e.p, e.offset, oi);
1498         if (rtype < 0) {
1499                 mark_bad_packed_object(e.p, real->hash);
1500                 return oid_object_info_extended(r, real, oi, 0);
1501         } else if (oi->whence == OI_PACKED) {
1502                 oi->u.packed.offset = e.offset;
1503                 oi->u.packed.pack = e.p;
1504                 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1505                                          rtype == OBJ_OFS_DELTA);
1506         }
1507
1508         return 0;
1509 }
1510
1511 /* returns enum object_type or negative */
1512 int oid_object_info(struct repository *r,
1513                     const struct object_id *oid,
1514                     unsigned long *sizep)
1515 {
1516         enum object_type type;
1517         struct object_info oi = OBJECT_INFO_INIT;
1518
1519         oi.typep = &type;
1520         oi.sizep = sizep;
1521         if (oid_object_info_extended(r, oid, &oi,
1522                                       OBJECT_INFO_LOOKUP_REPLACE) < 0)
1523                 return -1;
1524         return type;
1525 }
1526
1527 static void *read_object(struct repository *r,
1528                          const struct object_id *oid, enum object_type *type,
1529                          unsigned long *size)
1530 {
1531         struct object_info oi = OBJECT_INFO_INIT;
1532         void *content;
1533         oi.typep = type;
1534         oi.sizep = size;
1535         oi.contentp = &content;
1536
1537         if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1538                 return NULL;
1539         return content;
1540 }
1541
1542 int pretend_object_file(void *buf, unsigned long len, enum object_type type,
1543                         struct object_id *oid)
1544 {
1545         struct cached_object *co;
1546
1547         hash_object_file(buf, len, type_name(type), oid);
1548         if (has_object_file(oid) || find_cached_object(oid))
1549                 return 0;
1550         ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1551         co = &cached_objects[cached_object_nr++];
1552         co->size = len;
1553         co->type = type;
1554         co->buf = xmalloc(len);
1555         memcpy(co->buf, buf, len);
1556         oidcpy(&co->oid, oid);
1557         return 0;
1558 }
1559
1560 /*
1561  * This function dies on corrupt objects; the callers who want to
1562  * deal with them should arrange to call read_object() and give error
1563  * messages themselves.
1564  */
1565 void *read_object_file_extended(struct repository *r,
1566                                 const struct object_id *oid,
1567                                 enum object_type *type,
1568                                 unsigned long *size,
1569                                 int lookup_replace)
1570 {
1571         void *data;
1572         const struct packed_git *p;
1573         const char *path;
1574         struct stat st;
1575         const struct object_id *repl = lookup_replace ?
1576                 lookup_replace_object(r, oid) : oid;
1577
1578         errno = 0;
1579         data = read_object(r, repl, type, size);
1580         if (data)
1581                 return data;
1582
1583         if (errno && errno != ENOENT)
1584                 die_errno(_("failed to read object %s"), oid_to_hex(oid));
1585
1586         /* die if we replaced an object with one that does not exist */
1587         if (repl != oid)
1588                 die(_("replacement %s not found for %s"),
1589                     oid_to_hex(repl), oid_to_hex(oid));
1590
1591         if (!stat_loose_object(r, repl, &st, &path))
1592                 die(_("loose object %s (stored in %s) is corrupt"),
1593                     oid_to_hex(repl), path);
1594
1595         if ((p = has_packed_and_bad(r, repl->hash)) != NULL)
1596                 die(_("packed object %s (stored in %s) is corrupt"),
1597                     oid_to_hex(repl), p->pack_name);
1598
1599         return NULL;
1600 }
1601
1602 void *read_object_with_reference(struct repository *r,
1603                                  const struct object_id *oid,
1604                                  const char *required_type_name,
1605                                  unsigned long *size,
1606                                  struct object_id *actual_oid_return)
1607 {
1608         enum object_type type, required_type;
1609         void *buffer;
1610         unsigned long isize;
1611         struct object_id actual_oid;
1612
1613         required_type = type_from_string(required_type_name);
1614         oidcpy(&actual_oid, oid);
1615         while (1) {
1616                 int ref_length = -1;
1617                 const char *ref_type = NULL;
1618
1619                 buffer = repo_read_object_file(r, &actual_oid, &type, &isize);
1620                 if (!buffer)
1621                         return NULL;
1622                 if (type == required_type) {
1623                         *size = isize;
1624                         if (actual_oid_return)
1625                                 oidcpy(actual_oid_return, &actual_oid);
1626                         return buffer;
1627                 }
1628                 /* Handle references */
1629                 else if (type == OBJ_COMMIT)
1630                         ref_type = "tree ";
1631                 else if (type == OBJ_TAG)
1632                         ref_type = "object ";
1633                 else {
1634                         free(buffer);
1635                         return NULL;
1636                 }
1637                 ref_length = strlen(ref_type);
1638
1639                 if (ref_length + the_hash_algo->hexsz > isize ||
1640                     memcmp(buffer, ref_type, ref_length) ||
1641                     get_oid_hex((char *) buffer + ref_length, &actual_oid)) {
1642                         free(buffer);
1643                         return NULL;
1644                 }
1645                 free(buffer);
1646                 /* Now we have the ID of the referred-to object in
1647                  * actual_oid.  Check again. */
1648         }
1649 }
1650
1651 static void write_object_file_prepare(const void *buf, unsigned long len,
1652                                       const char *type, struct object_id *oid,
1653                                       char *hdr, int *hdrlen)
1654 {
1655         git_hash_ctx c;
1656
1657         /* Generate the header */
1658         *hdrlen = xsnprintf(hdr, *hdrlen, "%s %"PRIuMAX , type, (uintmax_t)len)+1;
1659
1660         /* Sha1.. */
1661         the_hash_algo->init_fn(&c);
1662         the_hash_algo->update_fn(&c, hdr, *hdrlen);
1663         the_hash_algo->update_fn(&c, buf, len);
1664         the_hash_algo->final_fn(oid->hash, &c);
1665 }
1666
1667 /*
1668  * Move the just written object into its final resting place.
1669  */
1670 int finalize_object_file(const char *tmpfile, const char *filename)
1671 {
1672         int ret = 0;
1673
1674         if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1675                 goto try_rename;
1676         else if (link(tmpfile, filename))
1677                 ret = errno;
1678
1679         /*
1680          * Coda hack - coda doesn't like cross-directory links,
1681          * so we fall back to a rename, which will mean that it
1682          * won't be able to check collisions, but that's not a
1683          * big deal.
1684          *
1685          * The same holds for FAT formatted media.
1686          *
1687          * When this succeeds, we just return.  We have nothing
1688          * left to unlink.
1689          */
1690         if (ret && ret != EEXIST) {
1691         try_rename:
1692                 if (!rename(tmpfile, filename))
1693                         goto out;
1694                 ret = errno;
1695         }
1696         unlink_or_warn(tmpfile);
1697         if (ret) {
1698                 if (ret != EEXIST) {
1699                         return error_errno(_("unable to write file %s"), filename);
1700                 }
1701                 /* FIXME!!! Collision check here ? */
1702         }
1703
1704 out:
1705         if (adjust_shared_perm(filename))
1706                 return error(_("unable to set permission to '%s'"), filename);
1707         return 0;
1708 }
1709
1710 static int write_buffer(int fd, const void *buf, size_t len)
1711 {
1712         if (write_in_full(fd, buf, len) < 0)
1713                 return error_errno(_("file write error"));
1714         return 0;
1715 }
1716
1717 int hash_object_file(const void *buf, unsigned long len, const char *type,
1718                      struct object_id *oid)
1719 {
1720         char hdr[MAX_HEADER_LEN];
1721         int hdrlen = sizeof(hdr);
1722         write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
1723         return 0;
1724 }
1725
1726 /* Finalize a file on disk, and close it. */
1727 static void close_loose_object(int fd)
1728 {
1729         if (fsync_object_files)
1730                 fsync_or_die(fd, "loose object file");
1731         if (close(fd) != 0)
1732                 die_errno(_("error when closing loose object file"));
1733 }
1734
1735 /* Size of directory component, including the ending '/' */
1736 static inline int directory_size(const char *filename)
1737 {
1738         const char *s = strrchr(filename, '/');
1739         if (!s)
1740                 return 0;
1741         return s - filename + 1;
1742 }
1743
1744 /*
1745  * This creates a temporary file in the same directory as the final
1746  * 'filename'
1747  *
1748  * We want to avoid cross-directory filename renames, because those
1749  * can have problems on various filesystems (FAT, NFS, Coda).
1750  */
1751 static int create_tmpfile(struct strbuf *tmp, const char *filename)
1752 {
1753         int fd, dirlen = directory_size(filename);
1754
1755         strbuf_reset(tmp);
1756         strbuf_add(tmp, filename, dirlen);
1757         strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1758         fd = git_mkstemp_mode(tmp->buf, 0444);
1759         if (fd < 0 && dirlen && errno == ENOENT) {
1760                 /*
1761                  * Make sure the directory exists; note that the contents
1762                  * of the buffer are undefined after mkstemp returns an
1763                  * error, so we have to rewrite the whole buffer from
1764                  * scratch.
1765                  */
1766                 strbuf_reset(tmp);
1767                 strbuf_add(tmp, filename, dirlen - 1);
1768                 if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1769                         return -1;
1770                 if (adjust_shared_perm(tmp->buf))
1771                         return -1;
1772
1773                 /* Try again */
1774                 strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1775                 fd = git_mkstemp_mode(tmp->buf, 0444);
1776         }
1777         return fd;
1778 }
1779
1780 static int write_loose_object(const struct object_id *oid, char *hdr,
1781                               int hdrlen, const void *buf, unsigned long len,
1782                               time_t mtime)
1783 {
1784         int fd, ret;
1785         unsigned char compressed[4096];
1786         git_zstream stream;
1787         git_hash_ctx c;
1788         struct object_id parano_oid;
1789         static struct strbuf tmp_file = STRBUF_INIT;
1790         static struct strbuf filename = STRBUF_INIT;
1791
1792         loose_object_path(the_repository, &filename, oid);
1793
1794         fd = create_tmpfile(&tmp_file, filename.buf);
1795         if (fd < 0) {
1796                 if (errno == EACCES)
1797                         return error(_("insufficient permission for adding an object to repository database %s"), get_object_directory());
1798                 else
1799                         return error_errno(_("unable to create temporary file"));
1800         }
1801
1802         /* Set it up */
1803         git_deflate_init(&stream, zlib_compression_level);
1804         stream.next_out = compressed;
1805         stream.avail_out = sizeof(compressed);
1806         the_hash_algo->init_fn(&c);
1807
1808         /* First header.. */
1809         stream.next_in = (unsigned char *)hdr;
1810         stream.avail_in = hdrlen;
1811         while (git_deflate(&stream, 0) == Z_OK)
1812                 ; /* nothing */
1813         the_hash_algo->update_fn(&c, hdr, hdrlen);
1814
1815         /* Then the data itself.. */
1816         stream.next_in = (void *)buf;
1817         stream.avail_in = len;
1818         do {
1819                 unsigned char *in0 = stream.next_in;
1820                 ret = git_deflate(&stream, Z_FINISH);
1821                 the_hash_algo->update_fn(&c, in0, stream.next_in - in0);
1822                 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1823                         die(_("unable to write loose object file"));
1824                 stream.next_out = compressed;
1825                 stream.avail_out = sizeof(compressed);
1826         } while (ret == Z_OK);
1827
1828         if (ret != Z_STREAM_END)
1829                 die(_("unable to deflate new object %s (%d)"), oid_to_hex(oid),
1830                     ret);
1831         ret = git_deflate_end_gently(&stream);
1832         if (ret != Z_OK)
1833                 die(_("deflateEnd on object %s failed (%d)"), oid_to_hex(oid),
1834                     ret);
1835         the_hash_algo->final_fn(parano_oid.hash, &c);
1836         if (!oideq(oid, &parano_oid))
1837                 die(_("confused by unstable object source data for %s"),
1838                     oid_to_hex(oid));
1839
1840         close_loose_object(fd);
1841
1842         if (mtime) {
1843                 struct utimbuf utb;
1844                 utb.actime = mtime;
1845                 utb.modtime = mtime;
1846                 if (utime(tmp_file.buf, &utb) < 0)
1847                         warning_errno(_("failed utime() on %s"), tmp_file.buf);
1848         }
1849
1850         return finalize_object_file(tmp_file.buf, filename.buf);
1851 }
1852
1853 static int freshen_loose_object(const struct object_id *oid)
1854 {
1855         return check_and_freshen(oid, 1);
1856 }
1857
1858 static int freshen_packed_object(const struct object_id *oid)
1859 {
1860         struct pack_entry e;
1861         if (!find_pack_entry(the_repository, oid, &e))
1862                 return 0;
1863         if (e.p->freshened)
1864                 return 1;
1865         if (!freshen_file(e.p->pack_name))
1866                 return 0;
1867         e.p->freshened = 1;
1868         return 1;
1869 }
1870
1871 int write_object_file(const void *buf, unsigned long len, const char *type,
1872                       struct object_id *oid)
1873 {
1874         char hdr[MAX_HEADER_LEN];
1875         int hdrlen = sizeof(hdr);
1876
1877         /* Normally if we have it in the pack then we do not bother writing
1878          * it out into .git/objects/??/?{38} file.
1879          */
1880         write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
1881         if (freshen_packed_object(oid) || freshen_loose_object(oid))
1882                 return 0;
1883         return write_loose_object(oid, hdr, hdrlen, buf, len, 0);
1884 }
1885
1886 int hash_object_file_literally(const void *buf, unsigned long len,
1887                                const char *type, struct object_id *oid,
1888                                unsigned flags)
1889 {
1890         char *header;
1891         int hdrlen, status = 0;
1892
1893         /* type string, SP, %lu of the length plus NUL must fit this */
1894         hdrlen = strlen(type) + MAX_HEADER_LEN;
1895         header = xmalloc(hdrlen);
1896         write_object_file_prepare(buf, len, type, oid, header, &hdrlen);
1897
1898         if (!(flags & HASH_WRITE_OBJECT))
1899                 goto cleanup;
1900         if (freshen_packed_object(oid) || freshen_loose_object(oid))
1901                 goto cleanup;
1902         status = write_loose_object(oid, header, hdrlen, buf, len, 0);
1903
1904 cleanup:
1905         free(header);
1906         return status;
1907 }
1908
1909 int force_object_loose(const struct object_id *oid, time_t mtime)
1910 {
1911         void *buf;
1912         unsigned long len;
1913         enum object_type type;
1914         char hdr[MAX_HEADER_LEN];
1915         int hdrlen;
1916         int ret;
1917
1918         if (has_loose_object(oid))
1919                 return 0;
1920         buf = read_object(the_repository, oid, &type, &len);
1921         if (!buf)
1922                 return error(_("cannot read object for %s"), oid_to_hex(oid));
1923         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(type), (uintmax_t)len) + 1;
1924         ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime);
1925         free(buf);
1926
1927         return ret;
1928 }
1929
1930 int repo_has_object_file_with_flags(struct repository *r,
1931                                     const struct object_id *oid, int flags)
1932 {
1933         if (!startup_info->have_repository)
1934                 return 0;
1935         return oid_object_info_extended(r, oid, NULL,
1936                                         flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1937 }
1938
1939 int repo_has_object_file(struct repository *r,
1940                          const struct object_id *oid)
1941 {
1942         return repo_has_object_file_with_flags(r, oid, 0);
1943 }
1944
1945 static void check_tree(const void *buf, size_t size)
1946 {
1947         struct tree_desc desc;
1948         struct name_entry entry;
1949
1950         init_tree_desc(&desc, buf, size);
1951         while (tree_entry(&desc, &entry))
1952                 /* do nothing
1953                  * tree_entry() will die() on malformed entries */
1954                 ;
1955 }
1956
1957 static void check_commit(const void *buf, size_t size)
1958 {
1959         struct commit c;
1960         memset(&c, 0, sizeof(c));
1961         if (parse_commit_buffer(the_repository, &c, buf, size, 0))
1962                 die(_("corrupt commit"));
1963 }
1964
1965 static void check_tag(const void *buf, size_t size)
1966 {
1967         struct tag t;
1968         memset(&t, 0, sizeof(t));
1969         if (parse_tag_buffer(the_repository, &t, buf, size))
1970                 die(_("corrupt tag"));
1971 }
1972
1973 static int index_mem(struct index_state *istate,
1974                      struct object_id *oid, void *buf, size_t size,
1975                      enum object_type type,
1976                      const char *path, unsigned flags)
1977 {
1978         int ret, re_allocated = 0;
1979         int write_object = flags & HASH_WRITE_OBJECT;
1980
1981         if (!type)
1982                 type = OBJ_BLOB;
1983
1984         /*
1985          * Convert blobs to git internal format
1986          */
1987         if ((type == OBJ_BLOB) && path) {
1988                 struct strbuf nbuf = STRBUF_INIT;
1989                 if (convert_to_git(istate, path, buf, size, &nbuf,
1990                                    get_conv_flags(flags))) {
1991                         buf = strbuf_detach(&nbuf, &size);
1992                         re_allocated = 1;
1993                 }
1994         }
1995         if (flags & HASH_FORMAT_CHECK) {
1996                 if (type == OBJ_TREE)
1997                         check_tree(buf, size);
1998                 if (type == OBJ_COMMIT)
1999                         check_commit(buf, size);
2000                 if (type == OBJ_TAG)
2001                         check_tag(buf, size);
2002         }
2003
2004         if (write_object)
2005                 ret = write_object_file(buf, size, type_name(type), oid);
2006         else
2007                 ret = hash_object_file(buf, size, type_name(type), oid);
2008         if (re_allocated)
2009                 free(buf);
2010         return ret;
2011 }
2012
2013 static int index_stream_convert_blob(struct index_state *istate,
2014                                      struct object_id *oid,
2015                                      int fd,
2016                                      const char *path,
2017                                      unsigned flags)
2018 {
2019         int ret;
2020         const int write_object = flags & HASH_WRITE_OBJECT;
2021         struct strbuf sbuf = STRBUF_INIT;
2022
2023         assert(path);
2024         assert(would_convert_to_git_filter_fd(istate, path));
2025
2026         convert_to_git_filter_fd(istate, path, fd, &sbuf,
2027                                  get_conv_flags(flags));
2028
2029         if (write_object)
2030                 ret = write_object_file(sbuf.buf, sbuf.len, type_name(OBJ_BLOB),
2031                                         oid);
2032         else
2033                 ret = hash_object_file(sbuf.buf, sbuf.len, type_name(OBJ_BLOB),
2034                                        oid);
2035         strbuf_release(&sbuf);
2036         return ret;
2037 }
2038
2039 static int index_pipe(struct index_state *istate, struct object_id *oid,
2040                       int fd, enum object_type type,
2041                       const char *path, unsigned flags)
2042 {
2043         struct strbuf sbuf = STRBUF_INIT;
2044         int ret;
2045
2046         if (strbuf_read(&sbuf, fd, 4096) >= 0)
2047                 ret = index_mem(istate, oid, sbuf.buf, sbuf.len, type, path, flags);
2048         else
2049                 ret = -1;
2050         strbuf_release(&sbuf);
2051         return ret;
2052 }
2053
2054 #define SMALL_FILE_SIZE (32*1024)
2055
2056 static int index_core(struct index_state *istate,
2057                       struct object_id *oid, int fd, size_t size,
2058                       enum object_type type, const char *path,
2059                       unsigned flags)
2060 {
2061         int ret;
2062
2063         if (!size) {
2064                 ret = index_mem(istate, oid, "", size, type, path, flags);
2065         } else if (size <= SMALL_FILE_SIZE) {
2066                 char *buf = xmalloc(size);
2067                 ssize_t read_result = read_in_full(fd, buf, size);
2068                 if (read_result < 0)
2069                         ret = error_errno(_("read error while indexing %s"),
2070                                           path ? path : "<unknown>");
2071                 else if (read_result != size)
2072                         ret = error(_("short read while indexing %s"),
2073                                     path ? path : "<unknown>");
2074                 else
2075                         ret = index_mem(istate, oid, buf, size, type, path, flags);
2076                 free(buf);
2077         } else {
2078                 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2079                 ret = index_mem(istate, oid, buf, size, type, path, flags);
2080                 munmap(buf, size);
2081         }
2082         return ret;
2083 }
2084
2085 /*
2086  * This creates one packfile per large blob unless bulk-checkin
2087  * machinery is "plugged".
2088  *
2089  * This also bypasses the usual "convert-to-git" dance, and that is on
2090  * purpose. We could write a streaming version of the converting
2091  * functions and insert that before feeding the data to fast-import
2092  * (or equivalent in-core API described above). However, that is
2093  * somewhat complicated, as we do not know the size of the filter
2094  * result, which we need to know beforehand when writing a git object.
2095  * Since the primary motivation for trying to stream from the working
2096  * tree file and to avoid mmaping it in core is to deal with large
2097  * binary blobs, they generally do not want to get any conversion, and
2098  * callers should avoid this code path when filters are requested.
2099  */
2100 static int index_stream(struct object_id *oid, int fd, size_t size,
2101                         enum object_type type, const char *path,
2102                         unsigned flags)
2103 {
2104         return index_bulk_checkin(oid, fd, size, type, path, flags);
2105 }
2106
2107 int index_fd(struct index_state *istate, struct object_id *oid,
2108              int fd, struct stat *st,
2109              enum object_type type, const char *path, unsigned flags)
2110 {
2111         int ret;
2112
2113         /*
2114          * Call xsize_t() only when needed to avoid potentially unnecessary
2115          * die() for large files.
2116          */
2117         if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(istate, path))
2118                 ret = index_stream_convert_blob(istate, oid, fd, path, flags);
2119         else if (!S_ISREG(st->st_mode))
2120                 ret = index_pipe(istate, oid, fd, type, path, flags);
2121         else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
2122                  (path && would_convert_to_git(istate, path)))
2123                 ret = index_core(istate, oid, fd, xsize_t(st->st_size),
2124                                  type, path, flags);
2125         else
2126                 ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
2127                                    flags);
2128         close(fd);
2129         return ret;
2130 }
2131
2132 int index_path(struct index_state *istate, struct object_id *oid,
2133                const char *path, struct stat *st, unsigned flags)
2134 {
2135         int fd;
2136         struct strbuf sb = STRBUF_INIT;
2137         int rc = 0;
2138
2139         switch (st->st_mode & S_IFMT) {
2140         case S_IFREG:
2141                 fd = open(path, O_RDONLY);
2142                 if (fd < 0)
2143                         return error_errno("open(\"%s\")", path);
2144                 if (index_fd(istate, oid, fd, st, OBJ_BLOB, path, flags) < 0)
2145                         return error(_("%s: failed to insert into database"),
2146                                      path);
2147                 break;
2148         case S_IFLNK:
2149                 if (strbuf_readlink(&sb, path, st->st_size))
2150                         return error_errno("readlink(\"%s\")", path);
2151                 if (!(flags & HASH_WRITE_OBJECT))
2152                         hash_object_file(sb.buf, sb.len, blob_type, oid);
2153                 else if (write_object_file(sb.buf, sb.len, blob_type, oid))
2154                         rc = error(_("%s: failed to insert into database"), path);
2155                 strbuf_release(&sb);
2156                 break;
2157         case S_IFDIR:
2158                 return resolve_gitlink_ref(path, "HEAD", oid);
2159         default:
2160                 return error(_("%s: unsupported file type"), path);
2161         }
2162         return rc;
2163 }
2164
2165 int read_pack_header(int fd, struct pack_header *header)
2166 {
2167         if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
2168                 /* "eof before pack header was fully read" */
2169                 return PH_ERROR_EOF;
2170
2171         if (header->hdr_signature != htonl(PACK_SIGNATURE))
2172                 /* "protocol error (pack signature mismatch detected)" */
2173                 return PH_ERROR_PACK_SIGNATURE;
2174         if (!pack_version_ok(header->hdr_version))
2175                 /* "protocol error (pack version unsupported)" */
2176                 return PH_ERROR_PROTOCOL;
2177         return 0;
2178 }
2179
2180 void assert_oid_type(const struct object_id *oid, enum object_type expect)
2181 {
2182         enum object_type type = oid_object_info(the_repository, oid, NULL);
2183         if (type < 0)
2184                 die(_("%s is not a valid object"), oid_to_hex(oid));
2185         if (type != expect)
2186                 die(_("%s is not a valid '%s' object"), oid_to_hex(oid),
2187                     type_name(expect));
2188 }
2189
2190 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
2191                                 struct strbuf *path,
2192                                 each_loose_object_fn obj_cb,
2193                                 each_loose_cruft_fn cruft_cb,
2194                                 each_loose_subdir_fn subdir_cb,
2195                                 void *data)
2196 {
2197         size_t origlen, baselen;
2198         DIR *dir;
2199         struct dirent *de;
2200         int r = 0;
2201         struct object_id oid;
2202
2203         if (subdir_nr > 0xff)
2204                 BUG("invalid loose object subdirectory: %x", subdir_nr);
2205
2206         origlen = path->len;
2207         strbuf_complete(path, '/');
2208         strbuf_addf(path, "%02x", subdir_nr);
2209
2210         dir = opendir(path->buf);
2211         if (!dir) {
2212                 if (errno != ENOENT)
2213                         r = error_errno(_("unable to open %s"), path->buf);
2214                 strbuf_setlen(path, origlen);
2215                 return r;
2216         }
2217
2218         oid.hash[0] = subdir_nr;
2219         strbuf_addch(path, '/');
2220         baselen = path->len;
2221
2222         while ((de = readdir(dir))) {
2223                 size_t namelen;
2224                 if (is_dot_or_dotdot(de->d_name))
2225                         continue;
2226
2227                 namelen = strlen(de->d_name);
2228                 strbuf_setlen(path, baselen);
2229                 strbuf_add(path, de->d_name, namelen);
2230                 if (namelen == the_hash_algo->hexsz - 2 &&
2231                     !hex_to_bytes(oid.hash + 1, de->d_name,
2232                                   the_hash_algo->rawsz - 1)) {
2233                         if (obj_cb) {
2234                                 r = obj_cb(&oid, path->buf, data);
2235                                 if (r)
2236                                         break;
2237                         }
2238                         continue;
2239                 }
2240
2241                 if (cruft_cb) {
2242                         r = cruft_cb(de->d_name, path->buf, data);
2243                         if (r)
2244                                 break;
2245                 }
2246         }
2247         closedir(dir);
2248
2249         strbuf_setlen(path, baselen - 1);
2250         if (!r && subdir_cb)
2251                 r = subdir_cb(subdir_nr, path->buf, data);
2252
2253         strbuf_setlen(path, origlen);
2254
2255         return r;
2256 }
2257
2258 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2259                             each_loose_object_fn obj_cb,
2260                             each_loose_cruft_fn cruft_cb,
2261                             each_loose_subdir_fn subdir_cb,
2262                             void *data)
2263 {
2264         int r = 0;
2265         int i;
2266
2267         for (i = 0; i < 256; i++) {
2268                 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2269                                                 subdir_cb, data);
2270                 if (r)
2271                         break;
2272         }
2273
2274         return r;
2275 }
2276
2277 int for_each_loose_file_in_objdir(const char *path,
2278                                   each_loose_object_fn obj_cb,
2279                                   each_loose_cruft_fn cruft_cb,
2280                                   each_loose_subdir_fn subdir_cb,
2281                                   void *data)
2282 {
2283         struct strbuf buf = STRBUF_INIT;
2284         int r;
2285
2286         strbuf_addstr(&buf, path);
2287         r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2288                                               subdir_cb, data);
2289         strbuf_release(&buf);
2290
2291         return r;
2292 }
2293
2294 int for_each_loose_object(each_loose_object_fn cb, void *data,
2295                           enum for_each_object_flags flags)
2296 {
2297         struct object_directory *odb;
2298
2299         prepare_alt_odb(the_repository);
2300         for (odb = the_repository->objects->odb; odb; odb = odb->next) {
2301                 int r = for_each_loose_file_in_objdir(odb->path, cb, NULL,
2302                                                       NULL, data);
2303                 if (r)
2304                         return r;
2305
2306                 if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2307                         break;
2308         }
2309
2310         return 0;
2311 }
2312
2313 static int append_loose_object(const struct object_id *oid, const char *path,
2314                                void *data)
2315 {
2316         oid_array_append(data, oid);
2317         return 0;
2318 }
2319
2320 struct oid_array *odb_loose_cache(struct object_directory *odb,
2321                                   const struct object_id *oid)
2322 {
2323         int subdir_nr = oid->hash[0];
2324         struct strbuf buf = STRBUF_INIT;
2325
2326         if (subdir_nr < 0 ||
2327             subdir_nr >= ARRAY_SIZE(odb->loose_objects_subdir_seen))
2328                 BUG("subdir_nr out of range");
2329
2330         if (odb->loose_objects_subdir_seen[subdir_nr])
2331                 return &odb->loose_objects_cache[subdir_nr];
2332
2333         strbuf_addstr(&buf, odb->path);
2334         for_each_file_in_obj_subdir(subdir_nr, &buf,
2335                                     append_loose_object,
2336                                     NULL, NULL,
2337                                     &odb->loose_objects_cache[subdir_nr]);
2338         odb->loose_objects_subdir_seen[subdir_nr] = 1;
2339         strbuf_release(&buf);
2340         return &odb->loose_objects_cache[subdir_nr];
2341 }
2342
2343 void odb_clear_loose_cache(struct object_directory *odb)
2344 {
2345         int i;
2346
2347         for (i = 0; i < ARRAY_SIZE(odb->loose_objects_cache); i++)
2348                 oid_array_clear(&odb->loose_objects_cache[i]);
2349         memset(&odb->loose_objects_subdir_seen, 0,
2350                sizeof(odb->loose_objects_subdir_seen));
2351 }
2352
2353 static int check_stream_oid(git_zstream *stream,
2354                             const char *hdr,
2355                             unsigned long size,
2356                             const char *path,
2357                             const struct object_id *expected_oid)
2358 {
2359         git_hash_ctx c;
2360         struct object_id real_oid;
2361         unsigned char buf[4096];
2362         unsigned long total_read;
2363         int status = Z_OK;
2364
2365         the_hash_algo->init_fn(&c);
2366         the_hash_algo->update_fn(&c, hdr, stream->total_out);
2367
2368         /*
2369          * We already read some bytes into hdr, but the ones up to the NUL
2370          * do not count against the object's content size.
2371          */
2372         total_read = stream->total_out - strlen(hdr) - 1;
2373
2374         /*
2375          * This size comparison must be "<=" to read the final zlib packets;
2376          * see the comment in unpack_loose_rest for details.
2377          */
2378         while (total_read <= size &&
2379                (status == Z_OK ||
2380                 (status == Z_BUF_ERROR && !stream->avail_out))) {
2381                 stream->next_out = buf;
2382                 stream->avail_out = sizeof(buf);
2383                 if (size - total_read < stream->avail_out)
2384                         stream->avail_out = size - total_read;
2385                 status = git_inflate(stream, Z_FINISH);
2386                 the_hash_algo->update_fn(&c, buf, stream->next_out - buf);
2387                 total_read += stream->next_out - buf;
2388         }
2389         git_inflate_end(stream);
2390
2391         if (status != Z_STREAM_END) {
2392                 error(_("corrupt loose object '%s'"), oid_to_hex(expected_oid));
2393                 return -1;
2394         }
2395         if (stream->avail_in) {
2396                 error(_("garbage at end of loose object '%s'"),
2397                       oid_to_hex(expected_oid));
2398                 return -1;
2399         }
2400
2401         the_hash_algo->final_fn(real_oid.hash, &c);
2402         if (!oideq(expected_oid, &real_oid)) {
2403                 error(_("hash mismatch for %s (expected %s)"), path,
2404                       oid_to_hex(expected_oid));
2405                 return -1;
2406         }
2407
2408         return 0;
2409 }
2410
2411 int read_loose_object(const char *path,
2412                       const struct object_id *expected_oid,
2413                       enum object_type *type,
2414                       unsigned long *size,
2415                       void **contents)
2416 {
2417         int ret = -1;
2418         void *map = NULL;
2419         unsigned long mapsize;
2420         git_zstream stream;
2421         char hdr[MAX_HEADER_LEN];
2422
2423         *contents = NULL;
2424
2425         map = map_loose_object_1(the_repository, path, NULL, &mapsize);
2426         if (!map) {
2427                 error_errno(_("unable to mmap %s"), path);
2428                 goto out;
2429         }
2430
2431         if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2432                 error(_("unable to unpack header of %s"), path);
2433                 goto out;
2434         }
2435
2436         *type = parse_loose_header(hdr, size);
2437         if (*type < 0) {
2438                 error(_("unable to parse header of %s"), path);
2439                 git_inflate_end(&stream);
2440                 goto out;
2441         }
2442
2443         if (*type == OBJ_BLOB && *size > big_file_threshold) {
2444                 if (check_stream_oid(&stream, hdr, *size, path, expected_oid) < 0)
2445                         goto out;
2446         } else {
2447                 *contents = unpack_loose_rest(&stream, hdr, *size, expected_oid);
2448                 if (!*contents) {
2449                         error(_("unable to unpack contents of %s"), path);
2450                         git_inflate_end(&stream);
2451                         goto out;
2452                 }
2453                 if (check_object_signature(expected_oid, *contents,
2454                                          *size, type_name(*type))) {
2455                         error(_("hash mismatch for %s (expected %s)"), path,
2456                               oid_to_hex(expected_oid));
2457                         free(*contents);
2458                         goto out;
2459                 }
2460         }
2461
2462         ret = 0; /* everything checks out */
2463
2464 out:
2465         if (map)
2466                 munmap(map, mapsize);
2467         return ret;
2468 }