Merge branch 'cc/trailers-corner-case-fix'
[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 "string-list.h"
11 #include "lockfile.h"
12 #include "delta.h"
13 #include "pack.h"
14 #include "blob.h"
15 #include "commit.h"
16 #include "run-command.h"
17 #include "tag.h"
18 #include "tree.h"
19 #include "tree-walk.h"
20 #include "refs.h"
21 #include "pack-revindex.h"
22 #include "sha1-lookup.h"
23 #include "bulk-checkin.h"
24 #include "streaming.h"
25 #include "dir.h"
26
27 #ifndef O_NOATIME
28 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
29 #define O_NOATIME 01000000
30 #else
31 #define O_NOATIME 0
32 #endif
33 #endif
34
35 #define SZ_FMT PRIuMAX
36 static inline uintmax_t sz_fmt(size_t s) { return s; }
37
38 const unsigned char null_sha1[20];
39
40 /*
41  * This is meant to hold a *small* number of objects that you would
42  * want read_sha1_file() to be able to return, but yet you do not want
43  * to write them into the object store (e.g. a browse-only
44  * application).
45  */
46 static struct cached_object {
47         unsigned char sha1[20];
48         enum object_type type;
49         void *buf;
50         unsigned long size;
51 } *cached_objects;
52 static int cached_object_nr, cached_object_alloc;
53
54 static struct cached_object empty_tree = {
55         EMPTY_TREE_SHA1_BIN_LITERAL,
56         OBJ_TREE,
57         "",
58         0
59 };
60
61 /*
62  * A pointer to the last packed_git in which an object was found.
63  * When an object is sought, we look in this packfile first, because
64  * objects that are looked up at similar times are often in the same
65  * packfile as one another.
66  */
67 static struct packed_git *last_found_pack;
68
69 static struct cached_object *find_cached_object(const unsigned char *sha1)
70 {
71         int i;
72         struct cached_object *co = cached_objects;
73
74         for (i = 0; i < cached_object_nr; i++, co++) {
75                 if (!hashcmp(co->sha1, sha1))
76                         return co;
77         }
78         if (!hashcmp(sha1, empty_tree.sha1))
79                 return &empty_tree;
80         return NULL;
81 }
82
83 int mkdir_in_gitdir(const char *path)
84 {
85         if (mkdir(path, 0777)) {
86                 int saved_errno = errno;
87                 struct stat st;
88                 struct strbuf sb = STRBUF_INIT;
89
90                 if (errno != EEXIST)
91                         return -1;
92                 /*
93                  * Are we looking at a path in a symlinked worktree
94                  * whose original repository does not yet have it?
95                  * e.g. .git/rr-cache pointing at its original
96                  * repository in which the user hasn't performed any
97                  * conflict resolution yet?
98                  */
99                 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
100                     strbuf_readlink(&sb, path, st.st_size) ||
101                     !is_absolute_path(sb.buf) ||
102                     mkdir(sb.buf, 0777)) {
103                         strbuf_release(&sb);
104                         errno = saved_errno;
105                         return -1;
106                 }
107                 strbuf_release(&sb);
108         }
109         return adjust_shared_perm(path);
110 }
111
112 enum scld_error safe_create_leading_directories(char *path)
113 {
114         char *next_component = path + offset_1st_component(path);
115         enum scld_error ret = SCLD_OK;
116
117         while (ret == SCLD_OK && next_component) {
118                 struct stat st;
119                 char *slash = next_component, slash_character;
120
121                 while (*slash && !is_dir_sep(*slash))
122                         slash++;
123
124                 if (!*slash)
125                         break;
126
127                 next_component = slash + 1;
128                 while (is_dir_sep(*next_component))
129                         next_component++;
130                 if (!*next_component)
131                         break;
132
133                 slash_character = *slash;
134                 *slash = '\0';
135                 if (!stat(path, &st)) {
136                         /* path exists */
137                         if (!S_ISDIR(st.st_mode))
138                                 ret = SCLD_EXISTS;
139                 } else if (mkdir(path, 0777)) {
140                         if (errno == EEXIST &&
141                             !stat(path, &st) && S_ISDIR(st.st_mode))
142                                 ; /* somebody created it since we checked */
143                         else if (errno == ENOENT)
144                                 /*
145                                  * Either mkdir() failed because
146                                  * somebody just pruned the containing
147                                  * directory, or stat() failed because
148                                  * the file that was in our way was
149                                  * just removed.  Either way, inform
150                                  * the caller that it might be worth
151                                  * trying again:
152                                  */
153                                 ret = SCLD_VANISHED;
154                         else
155                                 ret = SCLD_FAILED;
156                 } else if (adjust_shared_perm(path)) {
157                         ret = SCLD_PERMS;
158                 }
159                 *slash = slash_character;
160         }
161         return ret;
162 }
163
164 enum scld_error safe_create_leading_directories_const(const char *path)
165 {
166         /* path points to cache entries, so xstrdup before messing with it */
167         char *buf = xstrdup(path);
168         enum scld_error result = safe_create_leading_directories(buf);
169         free(buf);
170         return result;
171 }
172
173 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
174 {
175         int i;
176         for (i = 0; i < 20; i++) {
177                 static char hex[] = "0123456789abcdef";
178                 unsigned int val = sha1[i];
179                 char *pos = pathbuf + i*2 + (i > 0);
180                 *pos++ = hex[val >> 4];
181                 *pos = hex[val & 0xf];
182         }
183 }
184
185 const char *sha1_file_name(const unsigned char *sha1)
186 {
187         static char buf[PATH_MAX];
188         const char *objdir;
189         int len;
190
191         objdir = get_object_directory();
192         len = strlen(objdir);
193
194         /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
195         if (len + 43 > PATH_MAX)
196                 die("insanely long object directory %s", objdir);
197         memcpy(buf, objdir, len);
198         buf[len] = '/';
199         buf[len+3] = '/';
200         buf[len+42] = '\0';
201         fill_sha1_path(buf + len + 1, sha1);
202         return buf;
203 }
204
205 /*
206  * Return the name of the pack or index file with the specified sha1
207  * in its filename.  *base and *name are scratch space that must be
208  * provided by the caller.  which should be "pack" or "idx".
209  */
210 static char *sha1_get_pack_name(const unsigned char *sha1,
211                                 char **name, char **base, const char *which)
212 {
213         static const char hex[] = "0123456789abcdef";
214         char *buf;
215         int i;
216
217         if (!*base) {
218                 const char *sha1_file_directory = get_object_directory();
219                 int len = strlen(sha1_file_directory);
220                 *base = xmalloc(len + 60);
221                 sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
222                         sha1_file_directory, which);
223                 *name = *base + len + 11;
224         }
225
226         buf = *name;
227
228         for (i = 0; i < 20; i++) {
229                 unsigned int val = *sha1++;
230                 *buf++ = hex[val >> 4];
231                 *buf++ = hex[val & 0xf];
232         }
233
234         return *base;
235 }
236
237 char *sha1_pack_name(const unsigned char *sha1)
238 {
239         static char *name, *base;
240
241         return sha1_get_pack_name(sha1, &name, &base, "pack");
242 }
243
244 char *sha1_pack_index_name(const unsigned char *sha1)
245 {
246         static char *name, *base;
247
248         return sha1_get_pack_name(sha1, &name, &base, "idx");
249 }
250
251 struct alternate_object_database *alt_odb_list;
252 static struct alternate_object_database **alt_odb_tail;
253
254 /*
255  * Prepare alternate object database registry.
256  *
257  * The variable alt_odb_list points at the list of struct
258  * alternate_object_database.  The elements on this list come from
259  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
260  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
261  * whose contents is similar to that environment variable but can be
262  * LF separated.  Its base points at a statically allocated buffer that
263  * contains "/the/directory/corresponding/to/.git/objects/...", while
264  * its name points just after the slash at the end of ".git/objects/"
265  * in the example above, and has enough space to hold 40-byte hex
266  * SHA1, an extra slash for the first level indirection, and the
267  * terminating NUL.
268  */
269 static int link_alt_odb_entry(const char *entry, const char *relative_base,
270         int depth, const char *normalized_objdir)
271 {
272         struct alternate_object_database *ent;
273         struct alternate_object_database *alt;
274         int pfxlen, entlen;
275         struct strbuf pathbuf = STRBUF_INIT;
276
277         if (!is_absolute_path(entry) && relative_base) {
278                 strbuf_addstr(&pathbuf, real_path(relative_base));
279                 strbuf_addch(&pathbuf, '/');
280         }
281         strbuf_addstr(&pathbuf, entry);
282
283         normalize_path_copy(pathbuf.buf, pathbuf.buf);
284
285         pfxlen = strlen(pathbuf.buf);
286
287         /*
288          * The trailing slash after the directory name is given by
289          * this function at the end. Remove duplicates.
290          */
291         while (pfxlen && pathbuf.buf[pfxlen-1] == '/')
292                 pfxlen -= 1;
293
294         entlen = pfxlen + 43; /* '/' + 2 hex + '/' + 38 hex + NUL */
295         ent = xmalloc(sizeof(*ent) + entlen);
296         memcpy(ent->base, pathbuf.buf, pfxlen);
297         strbuf_release(&pathbuf);
298
299         ent->name = ent->base + pfxlen + 1;
300         ent->base[pfxlen + 3] = '/';
301         ent->base[pfxlen] = ent->base[entlen-1] = 0;
302
303         /* Detect cases where alternate disappeared */
304         if (!is_directory(ent->base)) {
305                 error("object directory %s does not exist; "
306                       "check .git/objects/info/alternates.",
307                       ent->base);
308                 free(ent);
309                 return -1;
310         }
311
312         /* Prevent the common mistake of listing the same
313          * thing twice, or object directory itself.
314          */
315         for (alt = alt_odb_list; alt; alt = alt->next) {
316                 if (pfxlen == alt->name - alt->base - 1 &&
317                     !memcmp(ent->base, alt->base, pfxlen)) {
318                         free(ent);
319                         return -1;
320                 }
321         }
322         if (!strcmp_icase(ent->base, normalized_objdir)) {
323                 free(ent);
324                 return -1;
325         }
326
327         /* add the alternate entry */
328         *alt_odb_tail = ent;
329         alt_odb_tail = &(ent->next);
330         ent->next = NULL;
331
332         /* recursively add alternates */
333         read_info_alternates(ent->base, depth + 1);
334
335         ent->base[pfxlen] = '/';
336
337         return 0;
338 }
339
340 static void link_alt_odb_entries(const char *alt, int len, int sep,
341                                  const char *relative_base, int depth)
342 {
343         struct string_list entries = STRING_LIST_INIT_NODUP;
344         char *alt_copy;
345         int i;
346         struct strbuf objdirbuf = STRBUF_INIT;
347
348         if (depth > 5) {
349                 error("%s: ignoring alternate object stores, nesting too deep.",
350                                 relative_base);
351                 return;
352         }
353
354         strbuf_add_absolute_path(&objdirbuf, get_object_directory());
355         normalize_path_copy(objdirbuf.buf, objdirbuf.buf);
356
357         alt_copy = xmemdupz(alt, len);
358         string_list_split_in_place(&entries, alt_copy, sep, -1);
359         for (i = 0; i < entries.nr; i++) {
360                 const char *entry = entries.items[i].string;
361                 if (entry[0] == '\0' || entry[0] == '#')
362                         continue;
363                 if (!is_absolute_path(entry) && depth) {
364                         error("%s: ignoring relative alternate object store %s",
365                                         relative_base, entry);
366                 } else {
367                         link_alt_odb_entry(entry, relative_base, depth, objdirbuf.buf);
368                 }
369         }
370         string_list_clear(&entries, 0);
371         free(alt_copy);
372         strbuf_release(&objdirbuf);
373 }
374
375 void read_info_alternates(const char * relative_base, int depth)
376 {
377         char *map;
378         size_t mapsz;
379         struct stat st;
380         const char alt_file_name[] = "info/alternates";
381         /* Given that relative_base is no longer than PATH_MAX,
382            ensure that "path" has enough space to append "/", the
383            file name, "info/alternates", and a trailing NUL.  */
384         char path[PATH_MAX + 1 + sizeof alt_file_name];
385         int fd;
386
387         sprintf(path, "%s/%s", relative_base, alt_file_name);
388         fd = git_open_noatime(path);
389         if (fd < 0)
390                 return;
391         if (fstat(fd, &st) || (st.st_size == 0)) {
392                 close(fd);
393                 return;
394         }
395         mapsz = xsize_t(st.st_size);
396         map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
397         close(fd);
398
399         link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
400
401         munmap(map, mapsz);
402 }
403
404 void add_to_alternates_file(const char *reference)
405 {
406         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
407         char *alts = git_pathdup("objects/info/alternates");
408         FILE *in, *out;
409
410         hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
411         out = fdopen_lock_file(lock, "w");
412         if (!out)
413                 die_errno("unable to fdopen alternates lockfile");
414
415         in = fopen(alts, "r");
416         if (in) {
417                 struct strbuf line = STRBUF_INIT;
418                 int found = 0;
419
420                 while (strbuf_getline(&line, in, '\n') != EOF) {
421                         if (!strcmp(reference, line.buf)) {
422                                 found = 1;
423                                 break;
424                         }
425                         fprintf_or_die(out, "%s\n", line.buf);
426                 }
427
428                 strbuf_release(&line);
429                 fclose(in);
430
431                 if (found) {
432                         rollback_lock_file(lock);
433                         lock = NULL;
434                 }
435         }
436         else if (errno != ENOENT)
437                 die_errno("unable to read alternates file");
438
439         if (lock) {
440                 fprintf_or_die(out, "%s\n", reference);
441                 if (commit_lock_file(lock))
442                         die_errno("unable to move new alternates file into place");
443                 if (alt_odb_tail)
444                         link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
445         }
446         free(alts);
447 }
448
449 int foreach_alt_odb(alt_odb_fn fn, void *cb)
450 {
451         struct alternate_object_database *ent;
452         int r = 0;
453
454         prepare_alt_odb();
455         for (ent = alt_odb_list; ent; ent = ent->next) {
456                 r = fn(ent, cb);
457                 if (r)
458                         break;
459         }
460         return r;
461 }
462
463 void prepare_alt_odb(void)
464 {
465         const char *alt;
466
467         if (alt_odb_tail)
468                 return;
469
470         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
471         if (!alt) alt = "";
472
473         alt_odb_tail = &alt_odb_list;
474         link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
475
476         read_info_alternates(get_object_directory(), 0);
477 }
478
479 /* Returns 1 if we have successfully freshened the file, 0 otherwise. */
480 static int freshen_file(const char *fn)
481 {
482         struct utimbuf t;
483         t.actime = t.modtime = time(NULL);
484         return !utime(fn, &t);
485 }
486
487 /*
488  * All of the check_and_freshen functions return 1 if the file exists and was
489  * freshened (if freshening was requested), 0 otherwise. If they return
490  * 0, you should not assume that it is safe to skip a write of the object (it
491  * either does not exist on disk, or has a stale mtime and may be subject to
492  * pruning).
493  */
494 static int check_and_freshen_file(const char *fn, int freshen)
495 {
496         if (access(fn, F_OK))
497                 return 0;
498         if (freshen && !freshen_file(fn))
499                 return 0;
500         return 1;
501 }
502
503 static int check_and_freshen_local(const unsigned char *sha1, int freshen)
504 {
505         return check_and_freshen_file(sha1_file_name(sha1), freshen);
506 }
507
508 static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
509 {
510         struct alternate_object_database *alt;
511         prepare_alt_odb();
512         for (alt = alt_odb_list; alt; alt = alt->next) {
513                 fill_sha1_path(alt->name, sha1);
514                 if (check_and_freshen_file(alt->base, freshen))
515                         return 1;
516         }
517         return 0;
518 }
519
520 static int check_and_freshen(const unsigned char *sha1, int freshen)
521 {
522         return check_and_freshen_local(sha1, freshen) ||
523                check_and_freshen_nonlocal(sha1, freshen);
524 }
525
526 int has_loose_object_nonlocal(const unsigned char *sha1)
527 {
528         return check_and_freshen_nonlocal(sha1, 0);
529 }
530
531 static int has_loose_object(const unsigned char *sha1)
532 {
533         return check_and_freshen(sha1, 0);
534 }
535
536 static unsigned int pack_used_ctr;
537 static unsigned int pack_mmap_calls;
538 static unsigned int peak_pack_open_windows;
539 static unsigned int pack_open_windows;
540 static unsigned int pack_open_fds;
541 static unsigned int pack_max_fds;
542 static size_t peak_pack_mapped;
543 static size_t pack_mapped;
544 struct packed_git *packed_git;
545
546 void pack_report(void)
547 {
548         fprintf(stderr,
549                 "pack_report: getpagesize()            = %10" SZ_FMT "\n"
550                 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
551                 "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
552                 sz_fmt(getpagesize()),
553                 sz_fmt(packed_git_window_size),
554                 sz_fmt(packed_git_limit));
555         fprintf(stderr,
556                 "pack_report: pack_used_ctr            = %10u\n"
557                 "pack_report: pack_mmap_calls          = %10u\n"
558                 "pack_report: pack_open_windows        = %10u / %10u\n"
559                 "pack_report: pack_mapped              = "
560                         "%10" SZ_FMT " / %10" SZ_FMT "\n",
561                 pack_used_ctr,
562                 pack_mmap_calls,
563                 pack_open_windows, peak_pack_open_windows,
564                 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
565 }
566
567 /*
568  * Open and mmap the index file at path, perform a couple of
569  * consistency checks, then record its information to p.  Return 0 on
570  * success.
571  */
572 static int check_packed_git_idx(const char *path, struct packed_git *p)
573 {
574         void *idx_map;
575         struct pack_idx_header *hdr;
576         size_t idx_size;
577         uint32_t version, nr, i, *index;
578         int fd = git_open_noatime(path);
579         struct stat st;
580
581         if (fd < 0)
582                 return -1;
583         if (fstat(fd, &st)) {
584                 close(fd);
585                 return -1;
586         }
587         idx_size = xsize_t(st.st_size);
588         if (idx_size < 4 * 256 + 20 + 20) {
589                 close(fd);
590                 return error("index file %s is too small", path);
591         }
592         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
593         close(fd);
594
595         hdr = idx_map;
596         if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
597                 version = ntohl(hdr->idx_version);
598                 if (version < 2 || version > 2) {
599                         munmap(idx_map, idx_size);
600                         return error("index file %s is version %"PRIu32
601                                      " and is not supported by this binary"
602                                      " (try upgrading GIT to a newer version)",
603                                      path, version);
604                 }
605         } else
606                 version = 1;
607
608         nr = 0;
609         index = idx_map;
610         if (version > 1)
611                 index += 2;  /* skip index header */
612         for (i = 0; i < 256; i++) {
613                 uint32_t n = ntohl(index[i]);
614                 if (n < nr) {
615                         munmap(idx_map, idx_size);
616                         return error("non-monotonic index %s", path);
617                 }
618                 nr = n;
619         }
620
621         if (version == 1) {
622                 /*
623                  * Total size:
624                  *  - 256 index entries 4 bytes each
625                  *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
626                  *  - 20-byte SHA1 of the packfile
627                  *  - 20-byte SHA1 file checksum
628                  */
629                 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
630                         munmap(idx_map, idx_size);
631                         return error("wrong index v1 file size in %s", path);
632                 }
633         } else if (version == 2) {
634                 /*
635                  * Minimum size:
636                  *  - 8 bytes of header
637                  *  - 256 index entries 4 bytes each
638                  *  - 20-byte sha1 entry * nr
639                  *  - 4-byte crc entry * nr
640                  *  - 4-byte offset entry * nr
641                  *  - 20-byte SHA1 of the packfile
642                  *  - 20-byte SHA1 file checksum
643                  * And after the 4-byte offset table might be a
644                  * variable sized table containing 8-byte entries
645                  * for offsets larger than 2^31.
646                  */
647                 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
648                 unsigned long max_size = min_size;
649                 if (nr)
650                         max_size += (nr - 1)*8;
651                 if (idx_size < min_size || idx_size > max_size) {
652                         munmap(idx_map, idx_size);
653                         return error("wrong index v2 file size in %s", path);
654                 }
655                 if (idx_size != min_size &&
656                     /*
657                      * make sure we can deal with large pack offsets.
658                      * 31-bit signed offset won't be enough, neither
659                      * 32-bit unsigned one will be.
660                      */
661                     (sizeof(off_t) <= 4)) {
662                         munmap(idx_map, idx_size);
663                         return error("pack too large for current definition of off_t in %s", path);
664                 }
665         }
666
667         p->index_version = version;
668         p->index_data = idx_map;
669         p->index_size = idx_size;
670         p->num_objects = nr;
671         return 0;
672 }
673
674 int open_pack_index(struct packed_git *p)
675 {
676         char *idx_name;
677         int ret;
678
679         if (p->index_data)
680                 return 0;
681
682         idx_name = xstrdup(p->pack_name);
683         strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
684         ret = check_packed_git_idx(idx_name, p);
685         free(idx_name);
686         return ret;
687 }
688
689 static void scan_windows(struct packed_git *p,
690         struct packed_git **lru_p,
691         struct pack_window **lru_w,
692         struct pack_window **lru_l)
693 {
694         struct pack_window *w, *w_l;
695
696         for (w_l = NULL, w = p->windows; w; w = w->next) {
697                 if (!w->inuse_cnt) {
698                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
699                                 *lru_p = p;
700                                 *lru_w = w;
701                                 *lru_l = w_l;
702                         }
703                 }
704                 w_l = w;
705         }
706 }
707
708 static int unuse_one_window(struct packed_git *current)
709 {
710         struct packed_git *p, *lru_p = NULL;
711         struct pack_window *lru_w = NULL, *lru_l = NULL;
712
713         if (current)
714                 scan_windows(current, &lru_p, &lru_w, &lru_l);
715         for (p = packed_git; p; p = p->next)
716                 scan_windows(p, &lru_p, &lru_w, &lru_l);
717         if (lru_p) {
718                 munmap(lru_w->base, lru_w->len);
719                 pack_mapped -= lru_w->len;
720                 if (lru_l)
721                         lru_l->next = lru_w->next;
722                 else
723                         lru_p->windows = lru_w->next;
724                 free(lru_w);
725                 pack_open_windows--;
726                 return 1;
727         }
728         return 0;
729 }
730
731 void release_pack_memory(size_t need)
732 {
733         size_t cur = pack_mapped;
734         while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
735                 ; /* nothing */
736 }
737
738 static void mmap_limit_check(size_t length)
739 {
740         static size_t limit = 0;
741         if (!limit) {
742                 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
743                 if (!limit)
744                         limit = SIZE_MAX;
745         }
746         if (length > limit)
747                 die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
748                     (uintmax_t)length, (uintmax_t)limit);
749 }
750
751 void *xmmap_gently(void *start, size_t length,
752                   int prot, int flags, int fd, off_t offset)
753 {
754         void *ret;
755
756         mmap_limit_check(length);
757         ret = mmap(start, length, prot, flags, fd, offset);
758         if (ret == MAP_FAILED) {
759                 if (!length)
760                         return NULL;
761                 release_pack_memory(length);
762                 ret = mmap(start, length, prot, flags, fd, offset);
763         }
764         return ret;
765 }
766
767 void *xmmap(void *start, size_t length,
768         int prot, int flags, int fd, off_t offset)
769 {
770         void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
771         if (ret == MAP_FAILED)
772                 die_errno("mmap failed");
773         return ret;
774 }
775
776 void close_pack_windows(struct packed_git *p)
777 {
778         while (p->windows) {
779                 struct pack_window *w = p->windows;
780
781                 if (w->inuse_cnt)
782                         die("pack '%s' still has open windows to it",
783                             p->pack_name);
784                 munmap(w->base, w->len);
785                 pack_mapped -= w->len;
786                 pack_open_windows--;
787                 p->windows = w->next;
788                 free(w);
789         }
790 }
791
792 /*
793  * The LRU pack is the one with the oldest MRU window, preferring packs
794  * with no used windows, or the oldest mtime if it has no windows allocated.
795  */
796 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
797 {
798         struct pack_window *w, *this_mru_w;
799         int has_windows_inuse = 0;
800
801         /*
802          * Reject this pack if it has windows and the previously selected
803          * one does not.  If this pack does not have windows, reject
804          * it if the pack file is newer than the previously selected one.
805          */
806         if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
807                 return;
808
809         for (w = this_mru_w = p->windows; w; w = w->next) {
810                 /*
811                  * Reject this pack if any of its windows are in use,
812                  * but the previously selected pack did not have any
813                  * inuse windows.  Otherwise, record that this pack
814                  * has windows in use.
815                  */
816                 if (w->inuse_cnt) {
817                         if (*accept_windows_inuse)
818                                 has_windows_inuse = 1;
819                         else
820                                 return;
821                 }
822
823                 if (w->last_used > this_mru_w->last_used)
824                         this_mru_w = w;
825
826                 /*
827                  * Reject this pack if it has windows that have been
828                  * used more recently than the previously selected pack.
829                  * If the previously selected pack had windows inuse and
830                  * we have not encountered a window in this pack that is
831                  * inuse, skip this check since we prefer a pack with no
832                  * inuse windows to one that has inuse windows.
833                  */
834                 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
835                     this_mru_w->last_used > (*mru_w)->last_used)
836                         return;
837         }
838
839         /*
840          * Select this pack.
841          */
842         *mru_w = this_mru_w;
843         *lru_p = p;
844         *accept_windows_inuse = has_windows_inuse;
845 }
846
847 static int close_one_pack(void)
848 {
849         struct packed_git *p, *lru_p = NULL;
850         struct pack_window *mru_w = NULL;
851         int accept_windows_inuse = 1;
852
853         for (p = packed_git; p; p = p->next) {
854                 if (p->pack_fd == -1)
855                         continue;
856                 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
857         }
858
859         if (lru_p) {
860                 close(lru_p->pack_fd);
861                 pack_open_fds--;
862                 lru_p->pack_fd = -1;
863                 return 1;
864         }
865
866         return 0;
867 }
868
869 void unuse_pack(struct pack_window **w_cursor)
870 {
871         struct pack_window *w = *w_cursor;
872         if (w) {
873                 w->inuse_cnt--;
874                 *w_cursor = NULL;
875         }
876 }
877
878 void close_pack_index(struct packed_git *p)
879 {
880         if (p->index_data) {
881                 munmap((void *)p->index_data, p->index_size);
882                 p->index_data = NULL;
883         }
884 }
885
886 /*
887  * This is used by git-repack in case a newly created pack happens to
888  * contain the same set of objects as an existing one.  In that case
889  * the resulting file might be different even if its name would be the
890  * same.  It is best to close any reference to the old pack before it is
891  * replaced on disk.  Of course no index pointers or windows for given pack
892  * must subsist at this point.  If ever objects from this pack are requested
893  * again, the new version of the pack will be reinitialized through
894  * reprepare_packed_git().
895  */
896 void free_pack_by_name(const char *pack_name)
897 {
898         struct packed_git *p, **pp = &packed_git;
899
900         while (*pp) {
901                 p = *pp;
902                 if (strcmp(pack_name, p->pack_name) == 0) {
903                         clear_delta_base_cache();
904                         close_pack_windows(p);
905                         if (p->pack_fd != -1) {
906                                 close(p->pack_fd);
907                                 pack_open_fds--;
908                         }
909                         close_pack_index(p);
910                         free(p->bad_object_sha1);
911                         *pp = p->next;
912                         if (last_found_pack == p)
913                                 last_found_pack = NULL;
914                         free(p);
915                         return;
916                 }
917                 pp = &p->next;
918         }
919 }
920
921 static unsigned int get_max_fd_limit(void)
922 {
923 #ifdef RLIMIT_NOFILE
924         {
925                 struct rlimit lim;
926
927                 if (!getrlimit(RLIMIT_NOFILE, &lim))
928                         return lim.rlim_cur;
929         }
930 #endif
931
932 #ifdef _SC_OPEN_MAX
933         {
934                 long open_max = sysconf(_SC_OPEN_MAX);
935                 if (0 < open_max)
936                         return open_max;
937                 /*
938                  * Otherwise, we got -1 for one of the two
939                  * reasons:
940                  *
941                  * (1) sysconf() did not understand _SC_OPEN_MAX
942                  *     and signaled an error with -1; or
943                  * (2) sysconf() said there is no limit.
944                  *
945                  * We _could_ clear errno before calling sysconf() to
946                  * tell these two cases apart and return a huge number
947                  * in the latter case to let the caller cap it to a
948                  * value that is not so selfish, but letting the
949                  * fallback OPEN_MAX codepath take care of these cases
950                  * is a lot simpler.
951                  */
952         }
953 #endif
954
955 #ifdef OPEN_MAX
956         return OPEN_MAX;
957 #else
958         return 1; /* see the caller ;-) */
959 #endif
960 }
961
962 /*
963  * Do not call this directly as this leaks p->pack_fd on error return;
964  * call open_packed_git() instead.
965  */
966 static int open_packed_git_1(struct packed_git *p)
967 {
968         struct stat st;
969         struct pack_header hdr;
970         unsigned char sha1[20];
971         unsigned char *idx_sha1;
972         long fd_flag;
973
974         if (!p->index_data && open_pack_index(p))
975                 return error("packfile %s index unavailable", p->pack_name);
976
977         if (!pack_max_fds) {
978                 unsigned int max_fds = get_max_fd_limit();
979
980                 /* Save 3 for stdin/stdout/stderr, 22 for work */
981                 if (25 < max_fds)
982                         pack_max_fds = max_fds - 25;
983                 else
984                         pack_max_fds = 1;
985         }
986
987         while (pack_max_fds <= pack_open_fds && close_one_pack())
988                 ; /* nothing */
989
990         p->pack_fd = git_open_noatime(p->pack_name);
991         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
992                 return -1;
993         pack_open_fds++;
994
995         /* If we created the struct before we had the pack we lack size. */
996         if (!p->pack_size) {
997                 if (!S_ISREG(st.st_mode))
998                         return error("packfile %s not a regular file", p->pack_name);
999                 p->pack_size = st.st_size;
1000         } else if (p->pack_size != st.st_size)
1001                 return error("packfile %s size changed", p->pack_name);
1002
1003         /* We leave these file descriptors open with sliding mmap;
1004          * there is no point keeping them open across exec(), though.
1005          */
1006         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
1007         if (fd_flag < 0)
1008                 return error("cannot determine file descriptor flags");
1009         fd_flag |= FD_CLOEXEC;
1010         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
1011                 return error("cannot set FD_CLOEXEC");
1012
1013         /* Verify we recognize this pack file format. */
1014         if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
1015                 return error("file %s is far too short to be a packfile", p->pack_name);
1016         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
1017                 return error("file %s is not a GIT packfile", p->pack_name);
1018         if (!pack_version_ok(hdr.hdr_version))
1019                 return error("packfile %s is version %"PRIu32" and not"
1020                         " supported (try upgrading GIT to a newer version)",
1021                         p->pack_name, ntohl(hdr.hdr_version));
1022
1023         /* Verify the pack matches its index. */
1024         if (p->num_objects != ntohl(hdr.hdr_entries))
1025                 return error("packfile %s claims to have %"PRIu32" objects"
1026                              " while index indicates %"PRIu32" objects",
1027                              p->pack_name, ntohl(hdr.hdr_entries),
1028                              p->num_objects);
1029         if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
1030                 return error("end of packfile %s is unavailable", p->pack_name);
1031         if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
1032                 return error("packfile %s signature is unavailable", p->pack_name);
1033         idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
1034         if (hashcmp(sha1, idx_sha1))
1035                 return error("packfile %s does not match index", p->pack_name);
1036         return 0;
1037 }
1038
1039 static int open_packed_git(struct packed_git *p)
1040 {
1041         if (!open_packed_git_1(p))
1042                 return 0;
1043         if (p->pack_fd != -1) {
1044                 close(p->pack_fd);
1045                 pack_open_fds--;
1046                 p->pack_fd = -1;
1047         }
1048         return -1;
1049 }
1050
1051 static int in_window(struct pack_window *win, off_t offset)
1052 {
1053         /* We must promise at least 20 bytes (one hash) after the
1054          * offset is available from this window, otherwise the offset
1055          * is not actually in this window and a different window (which
1056          * has that one hash excess) must be used.  This is to support
1057          * the object header and delta base parsing routines below.
1058          */
1059         off_t win_off = win->offset;
1060         return win_off <= offset
1061                 && (offset + 20) <= (win_off + win->len);
1062 }
1063
1064 unsigned char *use_pack(struct packed_git *p,
1065                 struct pack_window **w_cursor,
1066                 off_t offset,
1067                 unsigned long *left)
1068 {
1069         struct pack_window *win = *w_cursor;
1070
1071         /* Since packfiles end in a hash of their content and it's
1072          * pointless to ask for an offset into the middle of that
1073          * hash, and the in_window function above wouldn't match
1074          * don't allow an offset too close to the end of the file.
1075          */
1076         if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
1077                 die("packfile %s cannot be accessed", p->pack_name);
1078         if (offset > (p->pack_size - 20))
1079                 die("offset beyond end of packfile (truncated pack?)");
1080
1081         if (!win || !in_window(win, offset)) {
1082                 if (win)
1083                         win->inuse_cnt--;
1084                 for (win = p->windows; win; win = win->next) {
1085                         if (in_window(win, offset))
1086                                 break;
1087                 }
1088                 if (!win) {
1089                         size_t window_align = packed_git_window_size / 2;
1090                         off_t len;
1091
1092                         if (p->pack_fd == -1 && open_packed_git(p))
1093                                 die("packfile %s cannot be accessed", p->pack_name);
1094
1095                         win = xcalloc(1, sizeof(*win));
1096                         win->offset = (offset / window_align) * window_align;
1097                         len = p->pack_size - win->offset;
1098                         if (len > packed_git_window_size)
1099                                 len = packed_git_window_size;
1100                         win->len = (size_t)len;
1101                         pack_mapped += win->len;
1102                         while (packed_git_limit < pack_mapped
1103                                 && unuse_one_window(p))
1104                                 ; /* nothing */
1105                         win->base = xmmap(NULL, win->len,
1106                                 PROT_READ, MAP_PRIVATE,
1107                                 p->pack_fd, win->offset);
1108                         if (win->base == MAP_FAILED)
1109                                 die("packfile %s cannot be mapped: %s",
1110                                         p->pack_name,
1111                                         strerror(errno));
1112                         if (!win->offset && win->len == p->pack_size
1113                                 && !p->do_not_close) {
1114                                 close(p->pack_fd);
1115                                 pack_open_fds--;
1116                                 p->pack_fd = -1;
1117                         }
1118                         pack_mmap_calls++;
1119                         pack_open_windows++;
1120                         if (pack_mapped > peak_pack_mapped)
1121                                 peak_pack_mapped = pack_mapped;
1122                         if (pack_open_windows > peak_pack_open_windows)
1123                                 peak_pack_open_windows = pack_open_windows;
1124                         win->next = p->windows;
1125                         p->windows = win;
1126                 }
1127         }
1128         if (win != *w_cursor) {
1129                 win->last_used = pack_used_ctr++;
1130                 win->inuse_cnt++;
1131                 *w_cursor = win;
1132         }
1133         offset -= win->offset;
1134         if (left)
1135                 *left = win->len - xsize_t(offset);
1136         return win->base + offset;
1137 }
1138
1139 static struct packed_git *alloc_packed_git(int extra)
1140 {
1141         struct packed_git *p = xmalloc(sizeof(*p) + extra);
1142         memset(p, 0, sizeof(*p));
1143         p->pack_fd = -1;
1144         return p;
1145 }
1146
1147 static void try_to_free_pack_memory(size_t size)
1148 {
1149         release_pack_memory(size);
1150 }
1151
1152 struct packed_git *add_packed_git(const char *path, int path_len, int local)
1153 {
1154         static int have_set_try_to_free_routine;
1155         struct stat st;
1156         struct packed_git *p = alloc_packed_git(path_len + 2);
1157
1158         if (!have_set_try_to_free_routine) {
1159                 have_set_try_to_free_routine = 1;
1160                 set_try_to_free_routine(try_to_free_pack_memory);
1161         }
1162
1163         /*
1164          * Make sure a corresponding .pack file exists and that
1165          * the index looks sane.
1166          */
1167         path_len -= strlen(".idx");
1168         if (path_len < 1) {
1169                 free(p);
1170                 return NULL;
1171         }
1172         memcpy(p->pack_name, path, path_len);
1173
1174         strcpy(p->pack_name + path_len, ".keep");
1175         if (!access(p->pack_name, F_OK))
1176                 p->pack_keep = 1;
1177
1178         strcpy(p->pack_name + path_len, ".pack");
1179         if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
1180                 free(p);
1181                 return NULL;
1182         }
1183
1184         /* ok, it looks sane as far as we can check without
1185          * actually mapping the pack file.
1186          */
1187         p->pack_size = st.st_size;
1188         p->pack_local = local;
1189         p->mtime = st.st_mtime;
1190         if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
1191                 hashclr(p->sha1);
1192         return p;
1193 }
1194
1195 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
1196 {
1197         const char *path = sha1_pack_name(sha1);
1198         struct packed_git *p = alloc_packed_git(strlen(path) + 1);
1199
1200         strcpy(p->pack_name, path);
1201         hashcpy(p->sha1, sha1);
1202         if (check_packed_git_idx(idx_path, p)) {
1203                 free(p);
1204                 return NULL;
1205         }
1206
1207         return p;
1208 }
1209
1210 void install_packed_git(struct packed_git *pack)
1211 {
1212         if (pack->pack_fd != -1)
1213                 pack_open_fds++;
1214
1215         pack->next = packed_git;
1216         packed_git = pack;
1217 }
1218
1219 void (*report_garbage)(const char *desc, const char *path);
1220
1221 static void report_helper(const struct string_list *list,
1222                           int seen_bits, int first, int last)
1223 {
1224         const char *msg;
1225         switch (seen_bits) {
1226         case 0:
1227                 msg = "no corresponding .idx or .pack";
1228                 break;
1229         case 1:
1230                 msg = "no corresponding .idx";
1231                 break;
1232         case 2:
1233                 msg = "no corresponding .pack";
1234                 break;
1235         default:
1236                 return;
1237         }
1238         for (; first < last; first++)
1239                 report_garbage(msg, list->items[first].string);
1240 }
1241
1242 static void report_pack_garbage(struct string_list *list)
1243 {
1244         int i, baselen = -1, first = 0, seen_bits = 0;
1245
1246         if (!report_garbage)
1247                 return;
1248
1249         string_list_sort(list);
1250
1251         for (i = 0; i < list->nr; i++) {
1252                 const char *path = list->items[i].string;
1253                 if (baselen != -1 &&
1254                     strncmp(path, list->items[first].string, baselen)) {
1255                         report_helper(list, seen_bits, first, i);
1256                         baselen = -1;
1257                         seen_bits = 0;
1258                 }
1259                 if (baselen == -1) {
1260                         const char *dot = strrchr(path, '.');
1261                         if (!dot) {
1262                                 report_garbage("garbage found", path);
1263                                 continue;
1264                         }
1265                         baselen = dot - path + 1;
1266                         first = i;
1267                 }
1268                 if (!strcmp(path + baselen, "pack"))
1269                         seen_bits |= 1;
1270                 else if (!strcmp(path + baselen, "idx"))
1271                         seen_bits |= 2;
1272         }
1273         report_helper(list, seen_bits, first, list->nr);
1274 }
1275
1276 static void prepare_packed_git_one(char *objdir, int local)
1277 {
1278         struct strbuf path = STRBUF_INIT;
1279         size_t dirnamelen;
1280         DIR *dir;
1281         struct dirent *de;
1282         struct string_list garbage = STRING_LIST_INIT_DUP;
1283
1284         strbuf_addstr(&path, objdir);
1285         strbuf_addstr(&path, "/pack");
1286         dir = opendir(path.buf);
1287         if (!dir) {
1288                 if (errno != ENOENT)
1289                         error("unable to open object pack directory: %s: %s",
1290                               path.buf, strerror(errno));
1291                 strbuf_release(&path);
1292                 return;
1293         }
1294         strbuf_addch(&path, '/');
1295         dirnamelen = path.len;
1296         while ((de = readdir(dir)) != NULL) {
1297                 struct packed_git *p;
1298                 size_t base_len;
1299
1300                 if (is_dot_or_dotdot(de->d_name))
1301                         continue;
1302
1303                 strbuf_setlen(&path, dirnamelen);
1304                 strbuf_addstr(&path, de->d_name);
1305
1306                 base_len = path.len;
1307                 if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
1308                         /* Don't reopen a pack we already have. */
1309                         for (p = packed_git; p; p = p->next) {
1310                                 size_t len;
1311                                 if (strip_suffix(p->pack_name, ".pack", &len) &&
1312                                     len == base_len &&
1313                                     !memcmp(p->pack_name, path.buf, len))
1314                                         break;
1315                         }
1316                         if (p == NULL &&
1317                             /*
1318                              * See if it really is a valid .idx file with
1319                              * corresponding .pack file that we can map.
1320                              */
1321                             (p = add_packed_git(path.buf, path.len, local)) != NULL)
1322                                 install_packed_git(p);
1323                 }
1324
1325                 if (!report_garbage)
1326                         continue;
1327
1328                 if (ends_with(de->d_name, ".idx") ||
1329                     ends_with(de->d_name, ".pack") ||
1330                     ends_with(de->d_name, ".bitmap") ||
1331                     ends_with(de->d_name, ".keep"))
1332                         string_list_append(&garbage, path.buf);
1333                 else
1334                         report_garbage("garbage found", path.buf);
1335         }
1336         closedir(dir);
1337         report_pack_garbage(&garbage);
1338         string_list_clear(&garbage, 0);
1339         strbuf_release(&path);
1340 }
1341
1342 static int sort_pack(const void *a_, const void *b_)
1343 {
1344         struct packed_git *a = *((struct packed_git **)a_);
1345         struct packed_git *b = *((struct packed_git **)b_);
1346         int st;
1347
1348         /*
1349          * Local packs tend to contain objects specific to our
1350          * variant of the project than remote ones.  In addition,
1351          * remote ones could be on a network mounted filesystem.
1352          * Favor local ones for these reasons.
1353          */
1354         st = a->pack_local - b->pack_local;
1355         if (st)
1356                 return -st;
1357
1358         /*
1359          * Younger packs tend to contain more recent objects,
1360          * and more recent objects tend to get accessed more
1361          * often.
1362          */
1363         if (a->mtime < b->mtime)
1364                 return 1;
1365         else if (a->mtime == b->mtime)
1366                 return 0;
1367         return -1;
1368 }
1369
1370 static void rearrange_packed_git(void)
1371 {
1372         struct packed_git **ary, *p;
1373         int i, n;
1374
1375         for (n = 0, p = packed_git; p; p = p->next)
1376                 n++;
1377         if (n < 2)
1378                 return;
1379
1380         /* prepare an array of packed_git for easier sorting */
1381         ary = xcalloc(n, sizeof(struct packed_git *));
1382         for (n = 0, p = packed_git; p; p = p->next)
1383                 ary[n++] = p;
1384
1385         qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1386
1387         /* link them back again */
1388         for (i = 0; i < n - 1; i++)
1389                 ary[i]->next = ary[i + 1];
1390         ary[n - 1]->next = NULL;
1391         packed_git = ary[0];
1392
1393         free(ary);
1394 }
1395
1396 static int prepare_packed_git_run_once = 0;
1397 void prepare_packed_git(void)
1398 {
1399         struct alternate_object_database *alt;
1400
1401         if (prepare_packed_git_run_once)
1402                 return;
1403         prepare_packed_git_one(get_object_directory(), 1);
1404         prepare_alt_odb();
1405         for (alt = alt_odb_list; alt; alt = alt->next) {
1406                 alt->name[-1] = 0;
1407                 prepare_packed_git_one(alt->base, 0);
1408                 alt->name[-1] = '/';
1409         }
1410         rearrange_packed_git();
1411         prepare_packed_git_run_once = 1;
1412 }
1413
1414 void reprepare_packed_git(void)
1415 {
1416         prepare_packed_git_run_once = 0;
1417         prepare_packed_git();
1418 }
1419
1420 static void mark_bad_packed_object(struct packed_git *p,
1421                                    const unsigned char *sha1)
1422 {
1423         unsigned i;
1424         for (i = 0; i < p->num_bad_objects; i++)
1425                 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1426                         return;
1427         p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1));
1428         hashcpy(p->bad_object_sha1 + 20 * p->num_bad_objects, sha1);
1429         p->num_bad_objects++;
1430 }
1431
1432 static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1433 {
1434         struct packed_git *p;
1435         unsigned i;
1436
1437         for (p = packed_git; p; p = p->next)
1438                 for (i = 0; i < p->num_bad_objects; i++)
1439                         if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1440                                 return p;
1441         return NULL;
1442 }
1443
1444 /*
1445  * With an in-core object data in "map", rehash it to make sure the
1446  * object name actually matches "sha1" to detect object corruption.
1447  * With "map" == NULL, try reading the object named with "sha1" using
1448  * the streaming interface and rehash it to do the same.
1449  */
1450 int check_sha1_signature(const unsigned char *sha1, void *map,
1451                          unsigned long size, const char *type)
1452 {
1453         unsigned char real_sha1[20];
1454         enum object_type obj_type;
1455         struct git_istream *st;
1456         git_SHA_CTX c;
1457         char hdr[32];
1458         int hdrlen;
1459
1460         if (map) {
1461                 hash_sha1_file(map, size, type, real_sha1);
1462                 return hashcmp(sha1, real_sha1) ? -1 : 0;
1463         }
1464
1465         st = open_istream(sha1, &obj_type, &size, NULL);
1466         if (!st)
1467                 return -1;
1468
1469         /* Generate the header */
1470         hdrlen = sprintf(hdr, "%s %lu", typename(obj_type), size) + 1;
1471
1472         /* Sha1.. */
1473         git_SHA1_Init(&c);
1474         git_SHA1_Update(&c, hdr, hdrlen);
1475         for (;;) {
1476                 char buf[1024 * 16];
1477                 ssize_t readlen = read_istream(st, buf, sizeof(buf));
1478
1479                 if (readlen < 0) {
1480                         close_istream(st);
1481                         return -1;
1482                 }
1483                 if (!readlen)
1484                         break;
1485                 git_SHA1_Update(&c, buf, readlen);
1486         }
1487         git_SHA1_Final(real_sha1, &c);
1488         close_istream(st);
1489         return hashcmp(sha1, real_sha1) ? -1 : 0;
1490 }
1491
1492 int git_open_noatime(const char *name)
1493 {
1494         static int sha1_file_open_flag = O_NOATIME;
1495
1496         for (;;) {
1497                 int fd;
1498
1499                 errno = 0;
1500                 fd = open(name, O_RDONLY | sha1_file_open_flag);
1501                 if (fd >= 0)
1502                         return fd;
1503
1504                 /* Might the failure be due to O_NOATIME? */
1505                 if (errno != ENOENT && sha1_file_open_flag) {
1506                         sha1_file_open_flag = 0;
1507                         continue;
1508                 }
1509
1510                 return -1;
1511         }
1512 }
1513
1514 static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
1515 {
1516         struct alternate_object_database *alt;
1517
1518         if (!lstat(sha1_file_name(sha1), st))
1519                 return 0;
1520
1521         prepare_alt_odb();
1522         errno = ENOENT;
1523         for (alt = alt_odb_list; alt; alt = alt->next) {
1524                 fill_sha1_path(alt->name, sha1);
1525                 if (!lstat(alt->base, st))
1526                         return 0;
1527         }
1528
1529         return -1;
1530 }
1531
1532 static int open_sha1_file(const unsigned char *sha1)
1533 {
1534         int fd;
1535         struct alternate_object_database *alt;
1536         int most_interesting_errno;
1537
1538         fd = git_open_noatime(sha1_file_name(sha1));
1539         if (fd >= 0)
1540                 return fd;
1541         most_interesting_errno = errno;
1542
1543         prepare_alt_odb();
1544         for (alt = alt_odb_list; alt; alt = alt->next) {
1545                 fill_sha1_path(alt->name, sha1);
1546                 fd = git_open_noatime(alt->base);
1547                 if (fd >= 0)
1548                         return fd;
1549                 if (most_interesting_errno == ENOENT)
1550                         most_interesting_errno = errno;
1551         }
1552         errno = most_interesting_errno;
1553         return -1;
1554 }
1555
1556 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1557 {
1558         void *map;
1559         int fd;
1560
1561         fd = open_sha1_file(sha1);
1562         map = NULL;
1563         if (fd >= 0) {
1564                 struct stat st;
1565
1566                 if (!fstat(fd, &st)) {
1567                         *size = xsize_t(st.st_size);
1568                         if (!*size) {
1569                                 /* mmap() is forbidden on empty files */
1570                                 error("object file %s is empty", sha1_file_name(sha1));
1571                                 return NULL;
1572                         }
1573                         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1574                 }
1575                 close(fd);
1576         }
1577         return map;
1578 }
1579
1580 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1581                 unsigned long len, enum object_type *type, unsigned long *sizep)
1582 {
1583         unsigned shift;
1584         unsigned long size, c;
1585         unsigned long used = 0;
1586
1587         c = buf[used++];
1588         *type = (c >> 4) & 7;
1589         size = c & 15;
1590         shift = 4;
1591         while (c & 0x80) {
1592                 if (len <= used || bitsizeof(long) <= shift) {
1593                         error("bad object header");
1594                         size = used = 0;
1595                         break;
1596                 }
1597                 c = buf[used++];
1598                 size += (c & 0x7f) << shift;
1599                 shift += 7;
1600         }
1601         *sizep = size;
1602         return used;
1603 }
1604
1605 int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1606 {
1607         /* Get the data stream */
1608         memset(stream, 0, sizeof(*stream));
1609         stream->next_in = map;
1610         stream->avail_in = mapsize;
1611         stream->next_out = buffer;
1612         stream->avail_out = bufsiz;
1613
1614         git_inflate_init(stream);
1615         return git_inflate(stream, 0);
1616 }
1617
1618 static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
1619                                         unsigned long mapsize, void *buffer,
1620                                         unsigned long bufsiz, struct strbuf *header)
1621 {
1622         int status;
1623
1624         status = unpack_sha1_header(stream, map, mapsize, buffer, bufsiz);
1625
1626         /*
1627          * Check if entire header is unpacked in the first iteration.
1628          */
1629         if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1630                 return 0;
1631
1632         /*
1633          * buffer[0..bufsiz] was not large enough.  Copy the partial
1634          * result out to header, and then append the result of further
1635          * reading the stream.
1636          */
1637         strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1638         stream->next_out = buffer;
1639         stream->avail_out = bufsiz;
1640
1641         do {
1642                 status = git_inflate(stream, 0);
1643                 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1644                 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1645                         return 0;
1646                 stream->next_out = buffer;
1647                 stream->avail_out = bufsiz;
1648         } while (status != Z_STREAM_END);
1649         return -1;
1650 }
1651
1652 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1653 {
1654         int bytes = strlen(buffer) + 1;
1655         unsigned char *buf = xmallocz(size);
1656         unsigned long n;
1657         int status = Z_OK;
1658
1659         n = stream->total_out - bytes;
1660         if (n > size)
1661                 n = size;
1662         memcpy(buf, (char *) buffer + bytes, n);
1663         bytes = n;
1664         if (bytes <= size) {
1665                 /*
1666                  * The above condition must be (bytes <= size), not
1667                  * (bytes < size).  In other words, even though we
1668                  * expect no more output and set avail_out to zero,
1669                  * the input zlib stream may have bytes that express
1670                  * "this concludes the stream", and we *do* want to
1671                  * eat that input.
1672                  *
1673                  * Otherwise we would not be able to test that we
1674                  * consumed all the input to reach the expected size;
1675                  * we also want to check that zlib tells us that all
1676                  * went well with status == Z_STREAM_END at the end.
1677                  */
1678                 stream->next_out = buf + bytes;
1679                 stream->avail_out = size - bytes;
1680                 while (status == Z_OK)
1681                         status = git_inflate(stream, Z_FINISH);
1682         }
1683         if (status == Z_STREAM_END && !stream->avail_in) {
1684                 git_inflate_end(stream);
1685                 return buf;
1686         }
1687
1688         if (status < 0)
1689                 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1690         else if (stream->avail_in)
1691                 error("garbage at end of loose object '%s'",
1692                       sha1_to_hex(sha1));
1693         free(buf);
1694         return NULL;
1695 }
1696
1697 /*
1698  * We used to just use "sscanf()", but that's actually way
1699  * too permissive for what we want to check. So do an anal
1700  * object header parse by hand.
1701  */
1702 static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1703                                unsigned int flags)
1704 {
1705         const char *type_buf = hdr;
1706         unsigned long size;
1707         int type, type_len = 0;
1708
1709         /*
1710          * The type can be of any size but is followed by
1711          * a space.
1712          */
1713         for (;;) {
1714                 char c = *hdr++;
1715                 if (c == ' ')
1716                         break;
1717                 type_len++;
1718         }
1719
1720         type = type_from_string_gently(type_buf, type_len, 1);
1721         if (oi->typename)
1722                 strbuf_add(oi->typename, type_buf, type_len);
1723         /*
1724          * Set type to 0 if its an unknown object and
1725          * we're obtaining the type using '--allow-unkown-type'
1726          * option.
1727          */
1728         if ((flags & LOOKUP_UNKNOWN_OBJECT) && (type < 0))
1729                 type = 0;
1730         else if (type < 0)
1731                 die("invalid object type");
1732         if (oi->typep)
1733                 *oi->typep = type;
1734
1735         /*
1736          * The length must follow immediately, and be in canonical
1737          * decimal format (ie "010" is not valid).
1738          */
1739         size = *hdr++ - '0';
1740         if (size > 9)
1741                 return -1;
1742         if (size) {
1743                 for (;;) {
1744                         unsigned long c = *hdr - '0';
1745                         if (c > 9)
1746                                 break;
1747                         hdr++;
1748                         size = size * 10 + c;
1749                 }
1750         }
1751
1752         if (oi->sizep)
1753                 *oi->sizep = size;
1754
1755         /*
1756          * The length must be followed by a zero byte
1757          */
1758         return *hdr ? -1 : type;
1759 }
1760
1761 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1762 {
1763         struct object_info oi;
1764
1765         oi.sizep = sizep;
1766         oi.typename = NULL;
1767         oi.typep = NULL;
1768         return parse_sha1_header_extended(hdr, &oi, LOOKUP_REPLACE_OBJECT);
1769 }
1770
1771 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1772 {
1773         int ret;
1774         git_zstream stream;
1775         char hdr[8192];
1776
1777         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1778         if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1779                 return NULL;
1780
1781         return unpack_sha1_rest(&stream, hdr, *size, sha1);
1782 }
1783
1784 unsigned long get_size_from_delta(struct packed_git *p,
1785                                   struct pack_window **w_curs,
1786                                   off_t curpos)
1787 {
1788         const unsigned char *data;
1789         unsigned char delta_head[20], *in;
1790         git_zstream stream;
1791         int st;
1792
1793         memset(&stream, 0, sizeof(stream));
1794         stream.next_out = delta_head;
1795         stream.avail_out = sizeof(delta_head);
1796
1797         git_inflate_init(&stream);
1798         do {
1799                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1800                 stream.next_in = in;
1801                 st = git_inflate(&stream, Z_FINISH);
1802                 curpos += stream.next_in - in;
1803         } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1804                  stream.total_out < sizeof(delta_head));
1805         git_inflate_end(&stream);
1806         if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1807                 error("delta data unpack-initial failed");
1808                 return 0;
1809         }
1810
1811         /* Examine the initial part of the delta to figure out
1812          * the result size.
1813          */
1814         data = delta_head;
1815
1816         /* ignore base size */
1817         get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1818
1819         /* Read the result size */
1820         return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1821 }
1822
1823 static off_t get_delta_base(struct packed_git *p,
1824                                     struct pack_window **w_curs,
1825                                     off_t *curpos,
1826                                     enum object_type type,
1827                                     off_t delta_obj_offset)
1828 {
1829         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1830         off_t base_offset;
1831
1832         /* use_pack() assured us we have [base_info, base_info + 20)
1833          * as a range that we can look at without walking off the
1834          * end of the mapped window.  Its actually the hash size
1835          * that is assured.  An OFS_DELTA longer than the hash size
1836          * is stupid, as then a REF_DELTA would be smaller to store.
1837          */
1838         if (type == OBJ_OFS_DELTA) {
1839                 unsigned used = 0;
1840                 unsigned char c = base_info[used++];
1841                 base_offset = c & 127;
1842                 while (c & 128) {
1843                         base_offset += 1;
1844                         if (!base_offset || MSB(base_offset, 7))
1845                                 return 0;  /* overflow */
1846                         c = base_info[used++];
1847                         base_offset = (base_offset << 7) + (c & 127);
1848                 }
1849                 base_offset = delta_obj_offset - base_offset;
1850                 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1851                         return 0;  /* out of bound */
1852                 *curpos += used;
1853         } else if (type == OBJ_REF_DELTA) {
1854                 /* The base entry _must_ be in the same pack */
1855                 base_offset = find_pack_entry_one(base_info, p);
1856                 *curpos += 20;
1857         } else
1858                 die("I am totally screwed");
1859         return base_offset;
1860 }
1861
1862 /*
1863  * Like get_delta_base above, but we return the sha1 instead of the pack
1864  * offset. This means it is cheaper for REF deltas (we do not have to do
1865  * the final object lookup), but more expensive for OFS deltas (we
1866  * have to load the revidx to convert the offset back into a sha1).
1867  */
1868 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1869                                                 struct pack_window **w_curs,
1870                                                 off_t curpos,
1871                                                 enum object_type type,
1872                                                 off_t delta_obj_offset)
1873 {
1874         if (type == OBJ_REF_DELTA) {
1875                 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1876                 return base;
1877         } else if (type == OBJ_OFS_DELTA) {
1878                 struct revindex_entry *revidx;
1879                 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1880                                                    type, delta_obj_offset);
1881
1882                 if (!base_offset)
1883                         return NULL;
1884
1885                 revidx = find_pack_revindex(p, base_offset);
1886                 if (!revidx)
1887                         return NULL;
1888
1889                 return nth_packed_object_sha1(p, revidx->nr);
1890         } else
1891                 return NULL;
1892 }
1893
1894 int unpack_object_header(struct packed_git *p,
1895                          struct pack_window **w_curs,
1896                          off_t *curpos,
1897                          unsigned long *sizep)
1898 {
1899         unsigned char *base;
1900         unsigned long left;
1901         unsigned long used;
1902         enum object_type type;
1903
1904         /* use_pack() assures us we have [base, base + 20) available
1905          * as a range that we can look at.  (Its actually the hash
1906          * size that is assured.)  With our object header encoding
1907          * the maximum deflated object size is 2^137, which is just
1908          * insane, so we know won't exceed what we have been given.
1909          */
1910         base = use_pack(p, w_curs, *curpos, &left);
1911         used = unpack_object_header_buffer(base, left, &type, sizep);
1912         if (!used) {
1913                 type = OBJ_BAD;
1914         } else
1915                 *curpos += used;
1916
1917         return type;
1918 }
1919
1920 static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
1921 {
1922         int type;
1923         struct revindex_entry *revidx;
1924         const unsigned char *sha1;
1925         revidx = find_pack_revindex(p, obj_offset);
1926         if (!revidx)
1927                 return OBJ_BAD;
1928         sha1 = nth_packed_object_sha1(p, revidx->nr);
1929         mark_bad_packed_object(p, sha1);
1930         type = sha1_object_info(sha1, NULL);
1931         if (type <= OBJ_NONE)
1932                 return OBJ_BAD;
1933         return type;
1934 }
1935
1936 #define POI_STACK_PREALLOC 64
1937
1938 static enum object_type packed_to_object_type(struct packed_git *p,
1939                                               off_t obj_offset,
1940                                               enum object_type type,
1941                                               struct pack_window **w_curs,
1942                                               off_t curpos)
1943 {
1944         off_t small_poi_stack[POI_STACK_PREALLOC];
1945         off_t *poi_stack = small_poi_stack;
1946         int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1947
1948         while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1949                 off_t base_offset;
1950                 unsigned long size;
1951                 /* Push the object we're going to leave behind */
1952                 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1953                         poi_stack_alloc = alloc_nr(poi_stack_nr);
1954                         poi_stack = xmalloc(sizeof(off_t)*poi_stack_alloc);
1955                         memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1956                 } else {
1957                         ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1958                 }
1959                 poi_stack[poi_stack_nr++] = obj_offset;
1960                 /* If parsing the base offset fails, just unwind */
1961                 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1962                 if (!base_offset)
1963                         goto unwind;
1964                 curpos = obj_offset = base_offset;
1965                 type = unpack_object_header(p, w_curs, &curpos, &size);
1966                 if (type <= OBJ_NONE) {
1967                         /* If getting the base itself fails, we first
1968                          * retry the base, otherwise unwind */
1969                         type = retry_bad_packed_offset(p, base_offset);
1970                         if (type > OBJ_NONE)
1971                                 goto out;
1972                         goto unwind;
1973                 }
1974         }
1975
1976         switch (type) {
1977         case OBJ_BAD:
1978         case OBJ_COMMIT:
1979         case OBJ_TREE:
1980         case OBJ_BLOB:
1981         case OBJ_TAG:
1982                 break;
1983         default:
1984                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1985                       type, (uintmax_t)obj_offset, p->pack_name);
1986                 type = OBJ_BAD;
1987         }
1988
1989 out:
1990         if (poi_stack != small_poi_stack)
1991                 free(poi_stack);
1992         return type;
1993
1994 unwind:
1995         while (poi_stack_nr) {
1996                 obj_offset = poi_stack[--poi_stack_nr];
1997                 type = retry_bad_packed_offset(p, obj_offset);
1998                 if (type > OBJ_NONE)
1999                         goto out;
2000         }
2001         type = OBJ_BAD;
2002         goto out;
2003 }
2004
2005 static int packed_object_info(struct packed_git *p, off_t obj_offset,
2006                               struct object_info *oi)
2007 {
2008         struct pack_window *w_curs = NULL;
2009         unsigned long size;
2010         off_t curpos = obj_offset;
2011         enum object_type type;
2012
2013         /*
2014          * We always get the representation type, but only convert it to
2015          * a "real" type later if the caller is interested.
2016          */
2017         type = unpack_object_header(p, &w_curs, &curpos, &size);
2018
2019         if (oi->sizep) {
2020                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
2021                         off_t tmp_pos = curpos;
2022                         off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
2023                                                            type, obj_offset);
2024                         if (!base_offset) {
2025                                 type = OBJ_BAD;
2026                                 goto out;
2027                         }
2028                         *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
2029                         if (*oi->sizep == 0) {
2030                                 type = OBJ_BAD;
2031                                 goto out;
2032                         }
2033                 } else {
2034                         *oi->sizep = size;
2035                 }
2036         }
2037
2038         if (oi->disk_sizep) {
2039                 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2040                 *oi->disk_sizep = revidx[1].offset - obj_offset;
2041         }
2042
2043         if (oi->typep) {
2044                 *oi->typep = packed_to_object_type(p, obj_offset, type, &w_curs, curpos);
2045                 if (*oi->typep < 0) {
2046                         type = OBJ_BAD;
2047                         goto out;
2048                 }
2049         }
2050
2051         if (oi->delta_base_sha1) {
2052                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
2053                         const unsigned char *base;
2054
2055                         base = get_delta_base_sha1(p, &w_curs, curpos,
2056                                                    type, obj_offset);
2057                         if (!base) {
2058                                 type = OBJ_BAD;
2059                                 goto out;
2060                         }
2061
2062                         hashcpy(oi->delta_base_sha1, base);
2063                 } else
2064                         hashclr(oi->delta_base_sha1);
2065         }
2066
2067 out:
2068         unuse_pack(&w_curs);
2069         return type;
2070 }
2071
2072 static void *unpack_compressed_entry(struct packed_git *p,
2073                                     struct pack_window **w_curs,
2074                                     off_t curpos,
2075                                     unsigned long size)
2076 {
2077         int st;
2078         git_zstream stream;
2079         unsigned char *buffer, *in;
2080
2081         buffer = xmallocz_gently(size);
2082         if (!buffer)
2083                 return NULL;
2084         memset(&stream, 0, sizeof(stream));
2085         stream.next_out = buffer;
2086         stream.avail_out = size + 1;
2087
2088         git_inflate_init(&stream);
2089         do {
2090                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
2091                 stream.next_in = in;
2092                 st = git_inflate(&stream, Z_FINISH);
2093                 if (!stream.avail_out)
2094                         break; /* the payload is larger than it should be */
2095                 curpos += stream.next_in - in;
2096         } while (st == Z_OK || st == Z_BUF_ERROR);
2097         git_inflate_end(&stream);
2098         if ((st != Z_STREAM_END) || stream.total_out != size) {
2099                 free(buffer);
2100                 return NULL;
2101         }
2102
2103         return buffer;
2104 }
2105
2106 #define MAX_DELTA_CACHE (256)
2107
2108 static size_t delta_base_cached;
2109
2110 static struct delta_base_cache_lru_list {
2111         struct delta_base_cache_lru_list *prev;
2112         struct delta_base_cache_lru_list *next;
2113 } delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
2114
2115 static struct delta_base_cache_entry {
2116         struct delta_base_cache_lru_list lru;
2117         void *data;
2118         struct packed_git *p;
2119         off_t base_offset;
2120         unsigned long size;
2121         enum object_type type;
2122 } delta_base_cache[MAX_DELTA_CACHE];
2123
2124 static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
2125 {
2126         unsigned long hash;
2127
2128         hash = (unsigned long)p + (unsigned long)base_offset;
2129         hash += (hash >> 8) + (hash >> 16);
2130         return hash % MAX_DELTA_CACHE;
2131 }
2132
2133 static struct delta_base_cache_entry *
2134 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
2135 {
2136         unsigned long hash = pack_entry_hash(p, base_offset);
2137         return delta_base_cache + hash;
2138 }
2139
2140 static int eq_delta_base_cache_entry(struct delta_base_cache_entry *ent,
2141                                      struct packed_git *p, off_t base_offset)
2142 {
2143         return (ent->data && ent->p == p && ent->base_offset == base_offset);
2144 }
2145
2146 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
2147 {
2148         struct delta_base_cache_entry *ent;
2149         ent = get_delta_base_cache_entry(p, base_offset);
2150         return eq_delta_base_cache_entry(ent, p, base_offset);
2151 }
2152
2153 static void clear_delta_base_cache_entry(struct delta_base_cache_entry *ent)
2154 {
2155         ent->data = NULL;
2156         ent->lru.next->prev = ent->lru.prev;
2157         ent->lru.prev->next = ent->lru.next;
2158         delta_base_cached -= ent->size;
2159 }
2160
2161 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
2162         unsigned long *base_size, enum object_type *type, int keep_cache)
2163 {
2164         struct delta_base_cache_entry *ent;
2165         void *ret;
2166
2167         ent = get_delta_base_cache_entry(p, base_offset);
2168
2169         if (!eq_delta_base_cache_entry(ent, p, base_offset))
2170                 return unpack_entry(p, base_offset, type, base_size);
2171
2172         ret = ent->data;
2173
2174         if (!keep_cache)
2175                 clear_delta_base_cache_entry(ent);
2176         else
2177                 ret = xmemdupz(ent->data, ent->size);
2178         *type = ent->type;
2179         *base_size = ent->size;
2180         return ret;
2181 }
2182
2183 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
2184 {
2185         if (ent->data) {
2186                 free(ent->data);
2187                 ent->data = NULL;
2188                 ent->lru.next->prev = ent->lru.prev;
2189                 ent->lru.prev->next = ent->lru.next;
2190                 delta_base_cached -= ent->size;
2191         }
2192 }
2193
2194 void clear_delta_base_cache(void)
2195 {
2196         unsigned long p;
2197         for (p = 0; p < MAX_DELTA_CACHE; p++)
2198                 release_delta_base_cache(&delta_base_cache[p]);
2199 }
2200
2201 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
2202         void *base, unsigned long base_size, enum object_type type)
2203 {
2204         unsigned long hash = pack_entry_hash(p, base_offset);
2205         struct delta_base_cache_entry *ent = delta_base_cache + hash;
2206         struct delta_base_cache_lru_list *lru;
2207
2208         release_delta_base_cache(ent);
2209         delta_base_cached += base_size;
2210
2211         for (lru = delta_base_cache_lru.next;
2212              delta_base_cached > delta_base_cache_limit
2213              && lru != &delta_base_cache_lru;
2214              lru = lru->next) {
2215                 struct delta_base_cache_entry *f = (void *)lru;
2216                 if (f->type == OBJ_BLOB)
2217                         release_delta_base_cache(f);
2218         }
2219         for (lru = delta_base_cache_lru.next;
2220              delta_base_cached > delta_base_cache_limit
2221              && lru != &delta_base_cache_lru;
2222              lru = lru->next) {
2223                 struct delta_base_cache_entry *f = (void *)lru;
2224                 release_delta_base_cache(f);
2225         }
2226
2227         ent->p = p;
2228         ent->base_offset = base_offset;
2229         ent->type = type;
2230         ent->data = base;
2231         ent->size = base_size;
2232         ent->lru.next = &delta_base_cache_lru;
2233         ent->lru.prev = delta_base_cache_lru.prev;
2234         delta_base_cache_lru.prev->next = &ent->lru;
2235         delta_base_cache_lru.prev = &ent->lru;
2236 }
2237
2238 static void *read_object(const unsigned char *sha1, enum object_type *type,
2239                          unsigned long *size);
2240
2241 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
2242 {
2243         static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
2244         trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
2245                          p->pack_name, (uintmax_t)obj_offset);
2246 }
2247
2248 int do_check_packed_object_crc;
2249
2250 #define UNPACK_ENTRY_STACK_PREALLOC 64
2251 struct unpack_entry_stack_ent {
2252         off_t obj_offset;
2253         off_t curpos;
2254         unsigned long size;
2255 };
2256
2257 void *unpack_entry(struct packed_git *p, off_t obj_offset,
2258                    enum object_type *final_type, unsigned long *final_size)
2259 {
2260         struct pack_window *w_curs = NULL;
2261         off_t curpos = obj_offset;
2262         void *data = NULL;
2263         unsigned long size;
2264         enum object_type type;
2265         struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
2266         struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
2267         int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
2268         int base_from_cache = 0;
2269
2270         write_pack_access_log(p, obj_offset);
2271
2272         /* PHASE 1: drill down to the innermost base object */
2273         for (;;) {
2274                 off_t base_offset;
2275                 int i;
2276                 struct delta_base_cache_entry *ent;
2277
2278                 ent = get_delta_base_cache_entry(p, curpos);
2279                 if (eq_delta_base_cache_entry(ent, p, curpos)) {
2280                         type = ent->type;
2281                         data = ent->data;
2282                         size = ent->size;
2283                         clear_delta_base_cache_entry(ent);
2284                         base_from_cache = 1;
2285                         break;
2286                 }
2287
2288                 if (do_check_packed_object_crc && p->index_version > 1) {
2289                         struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2290                         unsigned long len = revidx[1].offset - obj_offset;
2291                         if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
2292                                 const unsigned char *sha1 =
2293                                         nth_packed_object_sha1(p, revidx->nr);
2294                                 error("bad packed object CRC for %s",
2295                                       sha1_to_hex(sha1));
2296                                 mark_bad_packed_object(p, sha1);
2297                                 unuse_pack(&w_curs);
2298                                 return NULL;
2299                         }
2300                 }
2301
2302                 type = unpack_object_header(p, &w_curs, &curpos, &size);
2303                 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
2304                         break;
2305
2306                 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
2307                 if (!base_offset) {
2308                         error("failed to validate delta base reference "
2309                               "at offset %"PRIuMAX" from %s",
2310                               (uintmax_t)curpos, p->pack_name);
2311                         /* bail to phase 2, in hopes of recovery */
2312                         data = NULL;
2313                         break;
2314                 }
2315
2316                 /* push object, proceed to base */
2317                 if (delta_stack_nr >= delta_stack_alloc
2318                     && delta_stack == small_delta_stack) {
2319                         delta_stack_alloc = alloc_nr(delta_stack_nr);
2320                         delta_stack = xmalloc(sizeof(*delta_stack)*delta_stack_alloc);
2321                         memcpy(delta_stack, small_delta_stack,
2322                                sizeof(*delta_stack)*delta_stack_nr);
2323                 } else {
2324                         ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
2325                 }
2326                 i = delta_stack_nr++;
2327                 delta_stack[i].obj_offset = obj_offset;
2328                 delta_stack[i].curpos = curpos;
2329                 delta_stack[i].size = size;
2330
2331                 curpos = obj_offset = base_offset;
2332         }
2333
2334         /* PHASE 2: handle the base */
2335         switch (type) {
2336         case OBJ_OFS_DELTA:
2337         case OBJ_REF_DELTA:
2338                 if (data)
2339                         die("BUG in unpack_entry: left loop at a valid delta");
2340                 break;
2341         case OBJ_COMMIT:
2342         case OBJ_TREE:
2343         case OBJ_BLOB:
2344         case OBJ_TAG:
2345                 if (!base_from_cache)
2346                         data = unpack_compressed_entry(p, &w_curs, curpos, size);
2347                 break;
2348         default:
2349                 data = NULL;
2350                 error("unknown object type %i at offset %"PRIuMAX" in %s",
2351                       type, (uintmax_t)obj_offset, p->pack_name);
2352         }
2353
2354         /* PHASE 3: apply deltas in order */
2355
2356         /* invariants:
2357          *   'data' holds the base data, or NULL if there was corruption
2358          */
2359         while (delta_stack_nr) {
2360                 void *delta_data;
2361                 void *base = data;
2362                 unsigned long delta_size, base_size = size;
2363                 int i;
2364
2365                 data = NULL;
2366
2367                 if (base)
2368                         add_delta_base_cache(p, obj_offset, base, base_size, type);
2369
2370                 if (!base) {
2371                         /*
2372                          * We're probably in deep shit, but let's try to fetch
2373                          * the required base anyway from another pack or loose.
2374                          * This is costly but should happen only in the presence
2375                          * of a corrupted pack, and is better than failing outright.
2376                          */
2377                         struct revindex_entry *revidx;
2378                         const unsigned char *base_sha1;
2379                         revidx = find_pack_revindex(p, obj_offset);
2380                         if (revidx) {
2381                                 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
2382                                 error("failed to read delta base object %s"
2383                                       " at offset %"PRIuMAX" from %s",
2384                                       sha1_to_hex(base_sha1), (uintmax_t)obj_offset,
2385                                       p->pack_name);
2386                                 mark_bad_packed_object(p, base_sha1);
2387                                 base = read_object(base_sha1, &type, &base_size);
2388                         }
2389                 }
2390
2391                 i = --delta_stack_nr;
2392                 obj_offset = delta_stack[i].obj_offset;
2393                 curpos = delta_stack[i].curpos;
2394                 delta_size = delta_stack[i].size;
2395
2396                 if (!base)
2397                         continue;
2398
2399                 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
2400
2401                 if (!delta_data) {
2402                         error("failed to unpack compressed delta "
2403                               "at offset %"PRIuMAX" from %s",
2404                               (uintmax_t)curpos, p->pack_name);
2405                         data = NULL;
2406                         continue;
2407                 }
2408
2409                 data = patch_delta(base, base_size,
2410                                    delta_data, delta_size,
2411                                    &size);
2412
2413                 /*
2414                  * We could not apply the delta; warn the user, but keep going.
2415                  * Our failure will be noticed either in the next iteration of
2416                  * the loop, or if this is the final delta, in the caller when
2417                  * we return NULL. Those code paths will take care of making
2418                  * a more explicit warning and retrying with another copy of
2419                  * the object.
2420                  */
2421                 if (!data)
2422                         error("failed to apply delta");
2423
2424                 free(delta_data);
2425         }
2426
2427         *final_type = type;
2428         *final_size = size;
2429
2430         unuse_pack(&w_curs);
2431
2432         if (delta_stack != small_delta_stack)
2433                 free(delta_stack);
2434
2435         return data;
2436 }
2437
2438 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
2439                                             uint32_t n)
2440 {
2441         const unsigned char *index = p->index_data;
2442         if (!index) {
2443                 if (open_pack_index(p))
2444                         return NULL;
2445                 index = p->index_data;
2446         }
2447         if (n >= p->num_objects)
2448                 return NULL;
2449         index += 4 * 256;
2450         if (p->index_version == 1) {
2451                 return index + 24 * n + 4;
2452         } else {
2453                 index += 8;
2454                 return index + 20 * n;
2455         }
2456 }
2457
2458 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
2459 {
2460         const unsigned char *index = p->index_data;
2461         index += 4 * 256;
2462         if (p->index_version == 1) {
2463                 return ntohl(*((uint32_t *)(index + 24 * n)));
2464         } else {
2465                 uint32_t off;
2466                 index += 8 + p->num_objects * (20 + 4);
2467                 off = ntohl(*((uint32_t *)(index + 4 * n)));
2468                 if (!(off & 0x80000000))
2469                         return off;
2470                 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
2471                 return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
2472                                    ntohl(*((uint32_t *)(index + 4)));
2473         }
2474 }
2475
2476 off_t find_pack_entry_one(const unsigned char *sha1,
2477                                   struct packed_git *p)
2478 {
2479         const uint32_t *level1_ofs = p->index_data;
2480         const unsigned char *index = p->index_data;
2481         unsigned hi, lo, stride;
2482         static int use_lookup = -1;
2483         static int debug_lookup = -1;
2484
2485         if (debug_lookup < 0)
2486                 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
2487
2488         if (!index) {
2489                 if (open_pack_index(p))
2490                         return 0;
2491                 level1_ofs = p->index_data;
2492                 index = p->index_data;
2493         }
2494         if (p->index_version > 1) {
2495                 level1_ofs += 2;
2496                 index += 8;
2497         }
2498         index += 4 * 256;
2499         hi = ntohl(level1_ofs[*sha1]);
2500         lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
2501         if (p->index_version > 1) {
2502                 stride = 20;
2503         } else {
2504                 stride = 24;
2505                 index += 4;
2506         }
2507
2508         if (debug_lookup)
2509                 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
2510                        sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
2511
2512         if (use_lookup < 0)
2513                 use_lookup = !!getenv("GIT_USE_LOOKUP");
2514         if (use_lookup) {
2515                 int pos = sha1_entry_pos(index, stride, 0,
2516                                          lo, hi, p->num_objects, sha1);
2517                 if (pos < 0)
2518                         return 0;
2519                 return nth_packed_object_offset(p, pos);
2520         }
2521
2522         do {
2523                 unsigned mi = (lo + hi) / 2;
2524                 int cmp = hashcmp(index + mi * stride, sha1);
2525
2526                 if (debug_lookup)
2527                         printf("lo %u hi %u rg %u mi %u\n",
2528                                lo, hi, hi - lo, mi);
2529                 if (!cmp)
2530                         return nth_packed_object_offset(p, mi);
2531                 if (cmp > 0)
2532                         hi = mi;
2533                 else
2534                         lo = mi+1;
2535         } while (lo < hi);
2536         return 0;
2537 }
2538
2539 int is_pack_valid(struct packed_git *p)
2540 {
2541         /* An already open pack is known to be valid. */
2542         if (p->pack_fd != -1)
2543                 return 1;
2544
2545         /* If the pack has one window completely covering the
2546          * file size, the pack is known to be valid even if
2547          * the descriptor is not currently open.
2548          */
2549         if (p->windows) {
2550                 struct pack_window *w = p->windows;
2551
2552                 if (!w->offset && w->len == p->pack_size)
2553                         return 1;
2554         }
2555
2556         /* Force the pack to open to prove its valid. */
2557         return !open_packed_git(p);
2558 }
2559
2560 static int fill_pack_entry(const unsigned char *sha1,
2561                            struct pack_entry *e,
2562                            struct packed_git *p)
2563 {
2564         off_t offset;
2565
2566         if (p->num_bad_objects) {
2567                 unsigned i;
2568                 for (i = 0; i < p->num_bad_objects; i++)
2569                         if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
2570                                 return 0;
2571         }
2572
2573         offset = find_pack_entry_one(sha1, p);
2574         if (!offset)
2575                 return 0;
2576
2577         /*
2578          * We are about to tell the caller where they can locate the
2579          * requested object.  We better make sure the packfile is
2580          * still here and can be accessed before supplying that
2581          * answer, as it may have been deleted since the index was
2582          * loaded!
2583          */
2584         if (!is_pack_valid(p))
2585                 return 0;
2586         e->offset = offset;
2587         e->p = p;
2588         hashcpy(e->sha1, sha1);
2589         return 1;
2590 }
2591
2592 /*
2593  * Iff a pack file contains the object named by sha1, return true and
2594  * store its location to e.
2595  */
2596 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
2597 {
2598         struct packed_git *p;
2599
2600         prepare_packed_git();
2601         if (!packed_git)
2602                 return 0;
2603
2604         if (last_found_pack && fill_pack_entry(sha1, e, last_found_pack))
2605                 return 1;
2606
2607         for (p = packed_git; p; p = p->next) {
2608                 if (p == last_found_pack)
2609                         continue; /* we already checked this one */
2610
2611                 if (fill_pack_entry(sha1, e, p)) {
2612                         last_found_pack = p;
2613                         return 1;
2614                 }
2615         }
2616         return 0;
2617 }
2618
2619 struct packed_git *find_sha1_pack(const unsigned char *sha1,
2620                                   struct packed_git *packs)
2621 {
2622         struct packed_git *p;
2623
2624         for (p = packs; p; p = p->next) {
2625                 if (find_pack_entry_one(sha1, p))
2626                         return p;
2627         }
2628         return NULL;
2629
2630 }
2631
2632 static int sha1_loose_object_info(const unsigned char *sha1,
2633                                   struct object_info *oi,
2634                                   int flags)
2635 {
2636         int status = 0;
2637         unsigned long mapsize;
2638         void *map;
2639         git_zstream stream;
2640         char hdr[32];
2641         struct strbuf hdrbuf = STRBUF_INIT;
2642
2643         if (oi->delta_base_sha1)
2644                 hashclr(oi->delta_base_sha1);
2645
2646         /*
2647          * If we don't care about type or size, then we don't
2648          * need to look inside the object at all. Note that we
2649          * do not optimize out the stat call, even if the
2650          * caller doesn't care about the disk-size, since our
2651          * return value implicitly indicates whether the
2652          * object even exists.
2653          */
2654         if (!oi->typep && !oi->typename && !oi->sizep) {
2655                 struct stat st;
2656                 if (stat_sha1_file(sha1, &st) < 0)
2657                         return -1;
2658                 if (oi->disk_sizep)
2659                         *oi->disk_sizep = st.st_size;
2660                 return 0;
2661         }
2662
2663         map = map_sha1_file(sha1, &mapsize);
2664         if (!map)
2665                 return -1;
2666         if (oi->disk_sizep)
2667                 *oi->disk_sizep = mapsize;
2668         if ((flags & LOOKUP_UNKNOWN_OBJECT)) {
2669                 if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
2670                         status = error("unable to unpack %s header with --allow-unknown-type",
2671                                        sha1_to_hex(sha1));
2672         } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2673                 status = error("unable to unpack %s header",
2674                                sha1_to_hex(sha1));
2675         if (status < 0)
2676                 ; /* Do nothing */
2677         else if (hdrbuf.len) {
2678                 if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
2679                         status = error("unable to parse %s header with --allow-unknown-type",
2680                                        sha1_to_hex(sha1));
2681         } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
2682                 status = error("unable to parse %s header", sha1_to_hex(sha1));
2683         git_inflate_end(&stream);
2684         munmap(map, mapsize);
2685         if (status && oi->typep)
2686                 *oi->typep = status;
2687         strbuf_release(&hdrbuf);
2688         return 0;
2689 }
2690
2691 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
2692 {
2693         struct cached_object *co;
2694         struct pack_entry e;
2695         int rtype;
2696         enum object_type real_type;
2697         const unsigned char *real = lookup_replace_object_extended(sha1, flags);
2698
2699         co = find_cached_object(real);
2700         if (co) {
2701                 if (oi->typep)
2702                         *(oi->typep) = co->type;
2703                 if (oi->sizep)
2704                         *(oi->sizep) = co->size;
2705                 if (oi->disk_sizep)
2706                         *(oi->disk_sizep) = 0;
2707                 if (oi->delta_base_sha1)
2708                         hashclr(oi->delta_base_sha1);
2709                 if (oi->typename)
2710                         strbuf_addstr(oi->typename, typename(co->type));
2711                 oi->whence = OI_CACHED;
2712                 return 0;
2713         }
2714
2715         if (!find_pack_entry(real, &e)) {
2716                 /* Most likely it's a loose object. */
2717                 if (!sha1_loose_object_info(real, oi, flags)) {
2718                         oi->whence = OI_LOOSE;
2719                         return 0;
2720                 }
2721
2722                 /* Not a loose object; someone else may have just packed it. */
2723                 reprepare_packed_git();
2724                 if (!find_pack_entry(real, &e))
2725                         return -1;
2726         }
2727
2728         /*
2729          * packed_object_info() does not follow the delta chain to
2730          * find out the real type, unless it is given oi->typep.
2731          */
2732         if (oi->typename && !oi->typep)
2733                 oi->typep = &real_type;
2734
2735         rtype = packed_object_info(e.p, e.offset, oi);
2736         if (rtype < 0) {
2737                 mark_bad_packed_object(e.p, real);
2738                 if (oi->typep == &real_type)
2739                         oi->typep = NULL;
2740                 return sha1_object_info_extended(real, oi, 0);
2741         } else if (in_delta_base_cache(e.p, e.offset)) {
2742                 oi->whence = OI_DBCACHED;
2743         } else {
2744                 oi->whence = OI_PACKED;
2745                 oi->u.packed.offset = e.offset;
2746                 oi->u.packed.pack = e.p;
2747                 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
2748                                          rtype == OBJ_OFS_DELTA);
2749         }
2750         if (oi->typename)
2751                 strbuf_addstr(oi->typename, typename(*oi->typep));
2752         if (oi->typep == &real_type)
2753                 oi->typep = NULL;
2754
2755         return 0;
2756 }
2757
2758 /* returns enum object_type or negative */
2759 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2760 {
2761         enum object_type type;
2762         struct object_info oi = {NULL};
2763
2764         oi.typep = &type;
2765         oi.sizep = sizep;
2766         if (sha1_object_info_extended(sha1, &oi, LOOKUP_REPLACE_OBJECT) < 0)
2767                 return -1;
2768         return type;
2769 }
2770
2771 static void *read_packed_sha1(const unsigned char *sha1,
2772                               enum object_type *type, unsigned long *size)
2773 {
2774         struct pack_entry e;
2775         void *data;
2776
2777         if (!find_pack_entry(sha1, &e))
2778                 return NULL;
2779         data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
2780         if (!data) {
2781                 /*
2782                  * We're probably in deep shit, but let's try to fetch
2783                  * the required object anyway from another pack or loose.
2784                  * This should happen only in the presence of a corrupted
2785                  * pack, and is better than failing outright.
2786                  */
2787                 error("failed to read object %s at offset %"PRIuMAX" from %s",
2788                       sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2789                 mark_bad_packed_object(e.p, sha1);
2790                 data = read_object(sha1, type, size);
2791         }
2792         return data;
2793 }
2794
2795 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2796                       unsigned char *sha1)
2797 {
2798         struct cached_object *co;
2799
2800         hash_sha1_file(buf, len, typename(type), sha1);
2801         if (has_sha1_file(sha1) || find_cached_object(sha1))
2802                 return 0;
2803         ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
2804         co = &cached_objects[cached_object_nr++];
2805         co->size = len;
2806         co->type = type;
2807         co->buf = xmalloc(len);
2808         memcpy(co->buf, buf, len);
2809         hashcpy(co->sha1, sha1);
2810         return 0;
2811 }
2812
2813 static void *read_object(const unsigned char *sha1, enum object_type *type,
2814                          unsigned long *size)
2815 {
2816         unsigned long mapsize;
2817         void *map, *buf;
2818         struct cached_object *co;
2819
2820         co = find_cached_object(sha1);
2821         if (co) {
2822                 *type = co->type;
2823                 *size = co->size;
2824                 return xmemdupz(co->buf, co->size);
2825         }
2826
2827         buf = read_packed_sha1(sha1, type, size);
2828         if (buf)
2829                 return buf;
2830         map = map_sha1_file(sha1, &mapsize);
2831         if (map) {
2832                 buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2833                 munmap(map, mapsize);
2834                 return buf;
2835         }
2836         reprepare_packed_git();
2837         return read_packed_sha1(sha1, type, size);
2838 }
2839
2840 /*
2841  * This function dies on corrupt objects; the callers who want to
2842  * deal with them should arrange to call read_object() and give error
2843  * messages themselves.
2844  */
2845 void *read_sha1_file_extended(const unsigned char *sha1,
2846                               enum object_type *type,
2847                               unsigned long *size,
2848                               unsigned flag)
2849 {
2850         void *data;
2851         const struct packed_git *p;
2852         const unsigned char *repl = lookup_replace_object_extended(sha1, flag);
2853
2854         errno = 0;
2855         data = read_object(repl, type, size);
2856         if (data)
2857                 return data;
2858
2859         if (errno && errno != ENOENT)
2860                 die_errno("failed to read object %s", sha1_to_hex(sha1));
2861
2862         /* die if we replaced an object with one that does not exist */
2863         if (repl != sha1)
2864                 die("replacement %s not found for %s",
2865                     sha1_to_hex(repl), sha1_to_hex(sha1));
2866
2867         if (has_loose_object(repl)) {
2868                 const char *path = sha1_file_name(sha1);
2869
2870                 die("loose object %s (stored in %s) is corrupt",
2871                     sha1_to_hex(repl), path);
2872         }
2873
2874         if ((p = has_packed_and_bad(repl)) != NULL)
2875                 die("packed object %s (stored in %s) is corrupt",
2876                     sha1_to_hex(repl), p->pack_name);
2877
2878         return NULL;
2879 }
2880
2881 void *read_object_with_reference(const unsigned char *sha1,
2882                                  const char *required_type_name,
2883                                  unsigned long *size,
2884                                  unsigned char *actual_sha1_return)
2885 {
2886         enum object_type type, required_type;
2887         void *buffer;
2888         unsigned long isize;
2889         unsigned char actual_sha1[20];
2890
2891         required_type = type_from_string(required_type_name);
2892         hashcpy(actual_sha1, sha1);
2893         while (1) {
2894                 int ref_length = -1;
2895                 const char *ref_type = NULL;
2896
2897                 buffer = read_sha1_file(actual_sha1, &type, &isize);
2898                 if (!buffer)
2899                         return NULL;
2900                 if (type == required_type) {
2901                         *size = isize;
2902                         if (actual_sha1_return)
2903                                 hashcpy(actual_sha1_return, actual_sha1);
2904                         return buffer;
2905                 }
2906                 /* Handle references */
2907                 else if (type == OBJ_COMMIT)
2908                         ref_type = "tree ";
2909                 else if (type == OBJ_TAG)
2910                         ref_type = "object ";
2911                 else {
2912                         free(buffer);
2913                         return NULL;
2914                 }
2915                 ref_length = strlen(ref_type);
2916
2917                 if (ref_length + 40 > isize ||
2918                     memcmp(buffer, ref_type, ref_length) ||
2919                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2920                         free(buffer);
2921                         return NULL;
2922                 }
2923                 free(buffer);
2924                 /* Now we have the ID of the referred-to object in
2925                  * actual_sha1.  Check again. */
2926         }
2927 }
2928
2929 static void write_sha1_file_prepare(const void *buf, unsigned long len,
2930                                     const char *type, unsigned char *sha1,
2931                                     char *hdr, int *hdrlen)
2932 {
2933         git_SHA_CTX c;
2934
2935         /* Generate the header */
2936         *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
2937
2938         /* Sha1.. */
2939         git_SHA1_Init(&c);
2940         git_SHA1_Update(&c, hdr, *hdrlen);
2941         git_SHA1_Update(&c, buf, len);
2942         git_SHA1_Final(sha1, &c);
2943 }
2944
2945 /*
2946  * Move the just written object into its final resting place.
2947  */
2948 int finalize_object_file(const char *tmpfile, const char *filename)
2949 {
2950         int ret = 0;
2951
2952         if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2953                 goto try_rename;
2954         else if (link(tmpfile, filename))
2955                 ret = errno;
2956
2957         /*
2958          * Coda hack - coda doesn't like cross-directory links,
2959          * so we fall back to a rename, which will mean that it
2960          * won't be able to check collisions, but that's not a
2961          * big deal.
2962          *
2963          * The same holds for FAT formatted media.
2964          *
2965          * When this succeeds, we just return.  We have nothing
2966          * left to unlink.
2967          */
2968         if (ret && ret != EEXIST) {
2969         try_rename:
2970                 if (!rename(tmpfile, filename))
2971                         goto out;
2972                 ret = errno;
2973         }
2974         unlink_or_warn(tmpfile);
2975         if (ret) {
2976                 if (ret != EEXIST) {
2977                         return error("unable to write sha1 filename %s: %s", filename, strerror(ret));
2978                 }
2979                 /* FIXME!!! Collision check here ? */
2980         }
2981
2982 out:
2983         if (adjust_shared_perm(filename))
2984                 return error("unable to set permission to '%s'", filename);
2985         return 0;
2986 }
2987
2988 static int write_buffer(int fd, const void *buf, size_t len)
2989 {
2990         if (write_in_full(fd, buf, len) < 0)
2991                 return error("file write error (%s)", strerror(errno));
2992         return 0;
2993 }
2994
2995 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2996                    unsigned char *sha1)
2997 {
2998         char hdr[32];
2999         int hdrlen;
3000         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
3001         return 0;
3002 }
3003
3004 /* Finalize a file on disk, and close it. */
3005 static void close_sha1_file(int fd)
3006 {
3007         if (fsync_object_files)
3008                 fsync_or_die(fd, "sha1 file");
3009         if (close(fd) != 0)
3010                 die_errno("error when closing sha1 file");
3011 }
3012
3013 /* Size of directory component, including the ending '/' */
3014 static inline int directory_size(const char *filename)
3015 {
3016         const char *s = strrchr(filename, '/');
3017         if (!s)
3018                 return 0;
3019         return s - filename + 1;
3020 }
3021
3022 /*
3023  * This creates a temporary file in the same directory as the final
3024  * 'filename'
3025  *
3026  * We want to avoid cross-directory filename renames, because those
3027  * can have problems on various filesystems (FAT, NFS, Coda).
3028  */
3029 static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
3030 {
3031         int fd, dirlen = directory_size(filename);
3032
3033         if (dirlen + 20 > bufsiz) {
3034                 errno = ENAMETOOLONG;
3035                 return -1;
3036         }
3037         memcpy(buffer, filename, dirlen);
3038         strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
3039         fd = git_mkstemp_mode(buffer, 0444);
3040         if (fd < 0 && dirlen && errno == ENOENT) {
3041                 /* Make sure the directory exists */
3042                 memcpy(buffer, filename, dirlen);
3043                 buffer[dirlen-1] = 0;
3044                 if (mkdir(buffer, 0777) && errno != EEXIST)
3045                         return -1;
3046                 if (adjust_shared_perm(buffer))
3047                         return -1;
3048
3049                 /* Try again */
3050                 strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
3051                 fd = git_mkstemp_mode(buffer, 0444);
3052         }
3053         return fd;
3054 }
3055
3056 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
3057                               const void *buf, unsigned long len, time_t mtime)
3058 {
3059         int fd, ret;
3060         unsigned char compressed[4096];
3061         git_zstream stream;
3062         git_SHA_CTX c;
3063         unsigned char parano_sha1[20];
3064         static char tmp_file[PATH_MAX];
3065         const char *filename = sha1_file_name(sha1);
3066
3067         fd = create_tmpfile(tmp_file, sizeof(tmp_file), filename);
3068         if (fd < 0) {
3069                 if (errno == EACCES)
3070                         return error("insufficient permission for adding an object to repository database %s", get_object_directory());
3071                 else
3072                         return error("unable to create temporary file: %s", strerror(errno));
3073         }
3074
3075         /* Set it up */
3076         git_deflate_init(&stream, zlib_compression_level);
3077         stream.next_out = compressed;
3078         stream.avail_out = sizeof(compressed);
3079         git_SHA1_Init(&c);
3080
3081         /* First header.. */
3082         stream.next_in = (unsigned char *)hdr;
3083         stream.avail_in = hdrlen;
3084         while (git_deflate(&stream, 0) == Z_OK)
3085                 ; /* nothing */
3086         git_SHA1_Update(&c, hdr, hdrlen);
3087
3088         /* Then the data itself.. */
3089         stream.next_in = (void *)buf;
3090         stream.avail_in = len;
3091         do {
3092                 unsigned char *in0 = stream.next_in;
3093                 ret = git_deflate(&stream, Z_FINISH);
3094                 git_SHA1_Update(&c, in0, stream.next_in - in0);
3095                 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
3096                         die("unable to write sha1 file");
3097                 stream.next_out = compressed;
3098                 stream.avail_out = sizeof(compressed);
3099         } while (ret == Z_OK);
3100
3101         if (ret != Z_STREAM_END)
3102                 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
3103         ret = git_deflate_end_gently(&stream);
3104         if (ret != Z_OK)
3105                 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
3106         git_SHA1_Final(parano_sha1, &c);
3107         if (hashcmp(sha1, parano_sha1) != 0)
3108                 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
3109
3110         close_sha1_file(fd);
3111
3112         if (mtime) {
3113                 struct utimbuf utb;
3114                 utb.actime = mtime;
3115                 utb.modtime = mtime;
3116                 if (utime(tmp_file, &utb) < 0)
3117                         warning("failed utime() on %s: %s",
3118                                 tmp_file, strerror(errno));
3119         }
3120
3121         return finalize_object_file(tmp_file, filename);
3122 }
3123
3124 static int freshen_loose_object(const unsigned char *sha1)
3125 {
3126         return check_and_freshen(sha1, 1);
3127 }
3128
3129 static int freshen_packed_object(const unsigned char *sha1)
3130 {
3131         struct pack_entry e;
3132         if (!find_pack_entry(sha1, &e))
3133                 return 0;
3134         if (e.p->freshened)
3135                 return 1;
3136         if (!freshen_file(e.p->pack_name))
3137                 return 0;
3138         e.p->freshened = 1;
3139         return 1;
3140 }
3141
3142 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
3143 {
3144         char hdr[32];
3145         int hdrlen;
3146
3147         /* Normally if we have it in the pack then we do not bother writing
3148          * it out into .git/objects/??/?{38} file.
3149          */
3150         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
3151         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3152                 return 0;
3153         return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
3154 }
3155
3156 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
3157                              unsigned char *sha1, unsigned flags)
3158 {
3159         char *header;
3160         int hdrlen, status = 0;
3161
3162         /* type string, SP, %lu of the length plus NUL must fit this */
3163         header = xmalloc(strlen(type) + 32);
3164         write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
3165
3166         if (!(flags & HASH_WRITE_OBJECT))
3167                 goto cleanup;
3168         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3169                 goto cleanup;
3170         status = write_loose_object(sha1, header, hdrlen, buf, len, 0);
3171
3172 cleanup:
3173         free(header);
3174         return status;
3175 }
3176
3177 int force_object_loose(const unsigned char *sha1, time_t mtime)
3178 {
3179         void *buf;
3180         unsigned long len;
3181         enum object_type type;
3182         char hdr[32];
3183         int hdrlen;
3184         int ret;
3185
3186         if (has_loose_object(sha1))
3187                 return 0;
3188         buf = read_packed_sha1(sha1, &type, &len);
3189         if (!buf)
3190                 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
3191         hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
3192         ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
3193         free(buf);
3194
3195         return ret;
3196 }
3197
3198 int has_pack_index(const unsigned char *sha1)
3199 {
3200         struct stat st;
3201         if (stat(sha1_pack_index_name(sha1), &st))
3202                 return 0;
3203         return 1;
3204 }
3205
3206 int has_sha1_pack(const unsigned char *sha1)
3207 {
3208         struct pack_entry e;
3209         return find_pack_entry(sha1, &e);
3210 }
3211
3212 int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
3213 {
3214         struct pack_entry e;
3215
3216         if (find_pack_entry(sha1, &e))
3217                 return 1;
3218         if (has_loose_object(sha1))
3219                 return 1;
3220         if (flags & HAS_SHA1_QUICK)
3221                 return 0;
3222         reprepare_packed_git();
3223         return find_pack_entry(sha1, &e);
3224 }
3225
3226 static void check_tree(const void *buf, size_t size)
3227 {
3228         struct tree_desc desc;
3229         struct name_entry entry;
3230
3231         init_tree_desc(&desc, buf, size);
3232         while (tree_entry(&desc, &entry))
3233                 /* do nothing
3234                  * tree_entry() will die() on malformed entries */
3235                 ;
3236 }
3237
3238 static void check_commit(const void *buf, size_t size)
3239 {
3240         struct commit c;
3241         memset(&c, 0, sizeof(c));
3242         if (parse_commit_buffer(&c, buf, size))
3243                 die("corrupt commit");
3244 }
3245
3246 static void check_tag(const void *buf, size_t size)
3247 {
3248         struct tag t;
3249         memset(&t, 0, sizeof(t));
3250         if (parse_tag_buffer(&t, buf, size))
3251                 die("corrupt tag");
3252 }
3253
3254 static int index_mem(unsigned char *sha1, void *buf, size_t size,
3255                      enum object_type type,
3256                      const char *path, unsigned flags)
3257 {
3258         int ret, re_allocated = 0;
3259         int write_object = flags & HASH_WRITE_OBJECT;
3260
3261         if (!type)
3262                 type = OBJ_BLOB;
3263
3264         /*
3265          * Convert blobs to git internal format
3266          */
3267         if ((type == OBJ_BLOB) && path) {
3268                 struct strbuf nbuf = STRBUF_INIT;
3269                 if (convert_to_git(path, buf, size, &nbuf,
3270                                    write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
3271                         buf = strbuf_detach(&nbuf, &size);
3272                         re_allocated = 1;
3273                 }
3274         }
3275         if (flags & HASH_FORMAT_CHECK) {
3276                 if (type == OBJ_TREE)
3277                         check_tree(buf, size);
3278                 if (type == OBJ_COMMIT)
3279                         check_commit(buf, size);
3280                 if (type == OBJ_TAG)
3281                         check_tag(buf, size);
3282         }
3283
3284         if (write_object)
3285                 ret = write_sha1_file(buf, size, typename(type), sha1);
3286         else
3287                 ret = hash_sha1_file(buf, size, typename(type), sha1);
3288         if (re_allocated)
3289                 free(buf);
3290         return ret;
3291 }
3292
3293 static int index_stream_convert_blob(unsigned char *sha1, int fd,
3294                                      const char *path, unsigned flags)
3295 {
3296         int ret;
3297         const int write_object = flags & HASH_WRITE_OBJECT;
3298         struct strbuf sbuf = STRBUF_INIT;
3299
3300         assert(path);
3301         assert(would_convert_to_git_filter_fd(path));
3302
3303         convert_to_git_filter_fd(path, fd, &sbuf,
3304                                  write_object ? safe_crlf : SAFE_CRLF_FALSE);
3305
3306         if (write_object)
3307                 ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3308                                       sha1);
3309         else
3310                 ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3311                                      sha1);
3312         strbuf_release(&sbuf);
3313         return ret;
3314 }
3315
3316 static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
3317                       const char *path, unsigned flags)
3318 {
3319         struct strbuf sbuf = STRBUF_INIT;
3320         int ret;
3321
3322         if (strbuf_read(&sbuf, fd, 4096) >= 0)
3323                 ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
3324         else
3325                 ret = -1;
3326         strbuf_release(&sbuf);
3327         return ret;
3328 }
3329
3330 #define SMALL_FILE_SIZE (32*1024)
3331
3332 static int index_core(unsigned char *sha1, int fd, size_t size,
3333                       enum object_type type, const char *path,
3334                       unsigned flags)
3335 {
3336         int ret;
3337
3338         if (!size) {
3339                 ret = index_mem(sha1, "", size, type, path, flags);
3340         } else if (size <= SMALL_FILE_SIZE) {
3341                 char *buf = xmalloc(size);
3342                 if (size == read_in_full(fd, buf, size))
3343                         ret = index_mem(sha1, buf, size, type, path, flags);
3344                 else
3345                         ret = error("short read %s", strerror(errno));
3346                 free(buf);
3347         } else {
3348                 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
3349                 ret = index_mem(sha1, buf, size, type, path, flags);
3350                 munmap(buf, size);
3351         }
3352         return ret;
3353 }
3354
3355 /*
3356  * This creates one packfile per large blob unless bulk-checkin
3357  * machinery is "plugged".
3358  *
3359  * This also bypasses the usual "convert-to-git" dance, and that is on
3360  * purpose. We could write a streaming version of the converting
3361  * functions and insert that before feeding the data to fast-import
3362  * (or equivalent in-core API described above). However, that is
3363  * somewhat complicated, as we do not know the size of the filter
3364  * result, which we need to know beforehand when writing a git object.
3365  * Since the primary motivation for trying to stream from the working
3366  * tree file and to avoid mmaping it in core is to deal with large
3367  * binary blobs, they generally do not want to get any conversion, and
3368  * callers should avoid this code path when filters are requested.
3369  */
3370 static int index_stream(unsigned char *sha1, int fd, size_t size,
3371                         enum object_type type, const char *path,
3372                         unsigned flags)
3373 {
3374         return index_bulk_checkin(sha1, fd, size, type, path, flags);
3375 }
3376
3377 int index_fd(unsigned char *sha1, int fd, struct stat *st,
3378              enum object_type type, const char *path, unsigned flags)
3379 {
3380         int ret;
3381
3382         /*
3383          * Call xsize_t() only when needed to avoid potentially unnecessary
3384          * die() for large files.
3385          */
3386         if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
3387                 ret = index_stream_convert_blob(sha1, fd, path, flags);
3388         else if (!S_ISREG(st->st_mode))
3389                 ret = index_pipe(sha1, fd, type, path, flags);
3390         else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
3391                  (path && would_convert_to_git(path)))
3392                 ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
3393                                  flags);
3394         else
3395                 ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
3396                                    flags);
3397         close(fd);
3398         return ret;
3399 }
3400
3401 int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
3402 {
3403         int fd;
3404         struct strbuf sb = STRBUF_INIT;
3405
3406         switch (st->st_mode & S_IFMT) {
3407         case S_IFREG:
3408                 fd = open(path, O_RDONLY);
3409                 if (fd < 0)
3410                         return error("open(\"%s\"): %s", path,
3411                                      strerror(errno));
3412                 if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
3413                         return error("%s: failed to insert into database",
3414                                      path);
3415                 break;
3416         case S_IFLNK:
3417                 if (strbuf_readlink(&sb, path, st->st_size)) {
3418                         char *errstr = strerror(errno);
3419                         return error("readlink(\"%s\"): %s", path,
3420                                      errstr);
3421                 }
3422                 if (!(flags & HASH_WRITE_OBJECT))
3423                         hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
3424                 else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
3425                         return error("%s: failed to insert into database",
3426                                      path);
3427                 strbuf_release(&sb);
3428                 break;
3429         case S_IFDIR:
3430                 return resolve_gitlink_ref(path, "HEAD", sha1);
3431         default:
3432                 return error("%s: unsupported file type", path);
3433         }
3434         return 0;
3435 }
3436
3437 int read_pack_header(int fd, struct pack_header *header)
3438 {
3439         if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
3440                 /* "eof before pack header was fully read" */
3441                 return PH_ERROR_EOF;
3442
3443         if (header->hdr_signature != htonl(PACK_SIGNATURE))
3444                 /* "protocol error (pack signature mismatch detected)" */
3445                 return PH_ERROR_PACK_SIGNATURE;
3446         if (!pack_version_ok(header->hdr_version))
3447                 /* "protocol error (pack version unsupported)" */
3448                 return PH_ERROR_PROTOCOL;
3449         return 0;
3450 }
3451
3452 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
3453 {
3454         enum object_type type = sha1_object_info(sha1, NULL);
3455         if (type < 0)
3456                 die("%s is not a valid object", sha1_to_hex(sha1));
3457         if (type != expect)
3458                 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
3459                     typename(expect));
3460 }
3461
3462 static int for_each_file_in_obj_subdir(int subdir_nr,
3463                                        struct strbuf *path,
3464                                        each_loose_object_fn obj_cb,
3465                                        each_loose_cruft_fn cruft_cb,
3466                                        each_loose_subdir_fn subdir_cb,
3467                                        void *data)
3468 {
3469         size_t baselen = path->len;
3470         DIR *dir = opendir(path->buf);
3471         struct dirent *de;
3472         int r = 0;
3473
3474         if (!dir) {
3475                 if (errno == ENOENT)
3476                         return 0;
3477                 return error("unable to open %s: %s", path->buf, strerror(errno));
3478         }
3479
3480         while ((de = readdir(dir))) {
3481                 if (is_dot_or_dotdot(de->d_name))
3482                         continue;
3483
3484                 strbuf_setlen(path, baselen);
3485                 strbuf_addf(path, "/%s", de->d_name);
3486
3487                 if (strlen(de->d_name) == 38)  {
3488                         char hex[41];
3489                         unsigned char sha1[20];
3490
3491                         snprintf(hex, sizeof(hex), "%02x%s",
3492                                  subdir_nr, de->d_name);
3493                         if (!get_sha1_hex(hex, sha1)) {
3494                                 if (obj_cb) {
3495                                         r = obj_cb(sha1, path->buf, data);
3496                                         if (r)
3497                                                 break;
3498                                 }
3499                                 continue;
3500                         }
3501                 }
3502
3503                 if (cruft_cb) {
3504                         r = cruft_cb(de->d_name, path->buf, data);
3505                         if (r)
3506                                 break;
3507                 }
3508         }
3509         strbuf_setlen(path, baselen);
3510
3511         if (!r && subdir_cb)
3512                 r = subdir_cb(subdir_nr, path->buf, data);
3513
3514         closedir(dir);
3515         return r;
3516 }
3517
3518 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
3519                             each_loose_object_fn obj_cb,
3520                             each_loose_cruft_fn cruft_cb,
3521                             each_loose_subdir_fn subdir_cb,
3522                             void *data)
3523 {
3524         size_t baselen = path->len;
3525         int r = 0;
3526         int i;
3527
3528         for (i = 0; i < 256; i++) {
3529                 strbuf_addf(path, "/%02x", i);
3530                 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
3531                                                 subdir_cb, data);
3532                 strbuf_setlen(path, baselen);
3533                 if (r)
3534                         break;
3535         }
3536
3537         return r;
3538 }
3539
3540 int for_each_loose_file_in_objdir(const char *path,
3541                                   each_loose_object_fn obj_cb,
3542                                   each_loose_cruft_fn cruft_cb,
3543                                   each_loose_subdir_fn subdir_cb,
3544                                   void *data)
3545 {
3546         struct strbuf buf = STRBUF_INIT;
3547         int r;
3548
3549         strbuf_addstr(&buf, path);
3550         r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
3551                                               subdir_cb, data);
3552         strbuf_release(&buf);
3553
3554         return r;
3555 }
3556
3557 struct loose_alt_odb_data {
3558         each_loose_object_fn *cb;
3559         void *data;
3560 };
3561
3562 static int loose_from_alt_odb(struct alternate_object_database *alt,
3563                               void *vdata)
3564 {
3565         struct loose_alt_odb_data *data = vdata;
3566         struct strbuf buf = STRBUF_INIT;
3567         int r;
3568
3569         /* copy base not including trailing '/' */
3570         strbuf_add(&buf, alt->base, alt->name - alt->base - 1);
3571         r = for_each_loose_file_in_objdir_buf(&buf,
3572                                               data->cb, NULL, NULL,
3573                                               data->data);
3574         strbuf_release(&buf);
3575         return r;
3576 }
3577
3578 int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
3579 {
3580         struct loose_alt_odb_data alt;
3581         int r;
3582
3583         r = for_each_loose_file_in_objdir(get_object_directory(),
3584                                           cb, NULL, NULL, data);
3585         if (r)
3586                 return r;
3587
3588         if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
3589                 return 0;
3590
3591         alt.cb = cb;
3592         alt.data = data;
3593         return foreach_alt_odb(loose_from_alt_odb, &alt);
3594 }
3595
3596 static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
3597 {
3598         uint32_t i;
3599         int r = 0;
3600
3601         for (i = 0; i < p->num_objects; i++) {
3602                 const unsigned char *sha1 = nth_packed_object_sha1(p, i);
3603
3604                 if (!sha1)
3605                         return error("unable to get sha1 of object %u in %s",
3606                                      i, p->pack_name);
3607
3608                 r = cb(sha1, p, i, data);
3609                 if (r)
3610                         break;
3611         }
3612         return r;
3613 }
3614
3615 int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
3616 {
3617         struct packed_git *p;
3618         int r = 0;
3619         int pack_errors = 0;
3620
3621         prepare_packed_git();
3622         for (p = packed_git; p; p = p->next) {
3623                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
3624                         continue;
3625                 if (open_pack_index(p)) {
3626                         pack_errors = 1;
3627                         continue;
3628                 }
3629                 r = for_each_object_in_pack(p, cb, data);
3630                 if (r)
3631                         break;
3632         }
3633         return r ? r : pack_errors;
3634 }