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