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