c02e785e99cb58eea9e7378f342e3f85a17e042d
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#include "mru.h"
27#include "list.h"
28
29#ifndef O_NOATIME
30#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
31#define O_NOATIME 01000000
32#else
33#define O_NOATIME 0
34#endif
35#endif
36
37#define SZ_FMT PRIuMAX
38static inline uintmax_t sz_fmt(size_t s) { return s; }
39
40const unsigned char null_sha1[20];
41const struct object_id null_oid;
42
43/*
44 * This is meant to hold a *small* number of objects that you would
45 * want read_sha1_file() to be able to return, but yet you do not want
46 * to write them into the object store (e.g. a browse-only
47 * application).
48 */
49static struct cached_object {
50 unsigned char sha1[20];
51 enum object_type type;
52 void *buf;
53 unsigned long size;
54} *cached_objects;
55static int cached_object_nr, cached_object_alloc;
56
57static struct cached_object empty_tree = {
58 EMPTY_TREE_SHA1_BIN_LITERAL,
59 OBJ_TREE,
60 "",
61 0
62};
63
64static struct cached_object *find_cached_object(const unsigned char *sha1)
65{
66 int i;
67 struct cached_object *co = cached_objects;
68
69 for (i = 0; i < cached_object_nr; i++, co++) {
70 if (!hashcmp(co->sha1, sha1))
71 return co;
72 }
73 if (!hashcmp(sha1, empty_tree.sha1))
74 return &empty_tree;
75 return NULL;
76}
77
78int mkdir_in_gitdir(const char *path)
79{
80 if (mkdir(path, 0777)) {
81 int saved_errno = errno;
82 struct stat st;
83 struct strbuf sb = STRBUF_INIT;
84
85 if (errno != EEXIST)
86 return -1;
87 /*
88 * Are we looking at a path in a symlinked worktree
89 * whose original repository does not yet have it?
90 * e.g. .git/rr-cache pointing at its original
91 * repository in which the user hasn't performed any
92 * conflict resolution yet?
93 */
94 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
95 strbuf_readlink(&sb, path, st.st_size) ||
96 !is_absolute_path(sb.buf) ||
97 mkdir(sb.buf, 0777)) {
98 strbuf_release(&sb);
99 errno = saved_errno;
100 return -1;
101 }
102 strbuf_release(&sb);
103 }
104 return adjust_shared_perm(path);
105}
106
107enum scld_error safe_create_leading_directories(char *path)
108{
109 char *next_component = path + offset_1st_component(path);
110 enum scld_error ret = SCLD_OK;
111
112 while (ret == SCLD_OK && next_component) {
113 struct stat st;
114 char *slash = next_component, slash_character;
115
116 while (*slash && !is_dir_sep(*slash))
117 slash++;
118
119 if (!*slash)
120 break;
121
122 next_component = slash + 1;
123 while (is_dir_sep(*next_component))
124 next_component++;
125 if (!*next_component)
126 break;
127
128 slash_character = *slash;
129 *slash = '\0';
130 if (!stat(path, &st)) {
131 /* path exists */
132 if (!S_ISDIR(st.st_mode))
133 ret = SCLD_EXISTS;
134 } else if (mkdir(path, 0777)) {
135 if (errno == EEXIST &&
136 !stat(path, &st) && S_ISDIR(st.st_mode))
137 ; /* somebody created it since we checked */
138 else if (errno == ENOENT)
139 /*
140 * Either mkdir() failed because
141 * somebody just pruned the containing
142 * directory, or stat() failed because
143 * the file that was in our way was
144 * just removed. Either way, inform
145 * the caller that it might be worth
146 * trying again:
147 */
148 ret = SCLD_VANISHED;
149 else
150 ret = SCLD_FAILED;
151 } else if (adjust_shared_perm(path)) {
152 ret = SCLD_PERMS;
153 }
154 *slash = slash_character;
155 }
156 return ret;
157}
158
159enum scld_error safe_create_leading_directories_const(const char *path)
160{
161 /* path points to cache entries, so xstrdup before messing with it */
162 char *buf = xstrdup(path);
163 enum scld_error result = safe_create_leading_directories(buf);
164 free(buf);
165 return result;
166}
167
168static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
169{
170 int i;
171 for (i = 0; i < 20; i++) {
172 static char hex[] = "0123456789abcdef";
173 unsigned int val = sha1[i];
174 char *pos = pathbuf + i*2 + (i > 0);
175 *pos++ = hex[val >> 4];
176 *pos = hex[val & 0xf];
177 }
178}
179
180const char *sha1_file_name(const unsigned char *sha1)
181{
182 static char buf[PATH_MAX];
183 const char *objdir;
184 int len;
185
186 objdir = get_object_directory();
187 len = strlen(objdir);
188
189 /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
190 if (len + 43 > PATH_MAX)
191 die("insanely long object directory %s", objdir);
192 memcpy(buf, objdir, len);
193 buf[len] = '/';
194 buf[len+3] = '/';
195 buf[len+42] = '\0';
196 fill_sha1_path(buf + len + 1, sha1);
197 return buf;
198}
199
200/*
201 * Return the name of the pack or index file with the specified sha1
202 * in its filename. *base and *name are scratch space that must be
203 * provided by the caller. which should be "pack" or "idx".
204 */
205static char *sha1_get_pack_name(const unsigned char *sha1,
206 struct strbuf *buf,
207 const char *which)
208{
209 strbuf_reset(buf);
210 strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
211 sha1_to_hex(sha1), which);
212 return buf->buf;
213}
214
215char *sha1_pack_name(const unsigned char *sha1)
216{
217 static struct strbuf buf = STRBUF_INIT;
218 return sha1_get_pack_name(sha1, &buf, "pack");
219}
220
221char *sha1_pack_index_name(const unsigned char *sha1)
222{
223 static struct strbuf buf = STRBUF_INIT;
224 return sha1_get_pack_name(sha1, &buf, "idx");
225}
226
227struct alternate_object_database *alt_odb_list;
228static struct alternate_object_database **alt_odb_tail;
229
230/*
231 * Prepare alternate object database registry.
232 *
233 * The variable alt_odb_list points at the list of struct
234 * alternate_object_database. The elements on this list come from
235 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
236 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
237 * whose contents is similar to that environment variable but can be
238 * LF separated. Its base points at a statically allocated buffer that
239 * contains "/the/directory/corresponding/to/.git/objects/...", while
240 * its name points just after the slash at the end of ".git/objects/"
241 * in the example above, and has enough space to hold 40-byte hex
242 * SHA1, an extra slash for the first level indirection, and the
243 * terminating NUL.
244 */
245static int link_alt_odb_entry(const char *entry, const char *relative_base,
246 int depth, const char *normalized_objdir)
247{
248 struct alternate_object_database *ent;
249 struct alternate_object_database *alt;
250 size_t pfxlen, entlen;
251 struct strbuf pathbuf = STRBUF_INIT;
252
253 if (!is_absolute_path(entry) && relative_base) {
254 strbuf_addstr(&pathbuf, real_path(relative_base));
255 strbuf_addch(&pathbuf, '/');
256 }
257 strbuf_addstr(&pathbuf, entry);
258
259 normalize_path_copy(pathbuf.buf, pathbuf.buf);
260
261 pfxlen = strlen(pathbuf.buf);
262
263 /*
264 * The trailing slash after the directory name is given by
265 * this function at the end. Remove duplicates.
266 */
267 while (pfxlen && pathbuf.buf[pfxlen-1] == '/')
268 pfxlen -= 1;
269
270 entlen = st_add(pfxlen, 43); /* '/' + 2 hex + '/' + 38 hex + NUL */
271 ent = xmalloc(st_add(sizeof(*ent), entlen));
272 memcpy(ent->base, pathbuf.buf, pfxlen);
273 strbuf_release(&pathbuf);
274
275 ent->name = ent->base + pfxlen + 1;
276 ent->base[pfxlen + 3] = '/';
277 ent->base[pfxlen] = ent->base[entlen-1] = 0;
278
279 /* Detect cases where alternate disappeared */
280 if (!is_directory(ent->base)) {
281 error("object directory %s does not exist; "
282 "check .git/objects/info/alternates.",
283 ent->base);
284 free(ent);
285 return -1;
286 }
287
288 /* Prevent the common mistake of listing the same
289 * thing twice, or object directory itself.
290 */
291 for (alt = alt_odb_list; alt; alt = alt->next) {
292 if (pfxlen == alt->name - alt->base - 1 &&
293 !memcmp(ent->base, alt->base, pfxlen)) {
294 free(ent);
295 return -1;
296 }
297 }
298 if (!fspathcmp(ent->base, normalized_objdir)) {
299 free(ent);
300 return -1;
301 }
302
303 /* add the alternate entry */
304 *alt_odb_tail = ent;
305 alt_odb_tail = &(ent->next);
306 ent->next = NULL;
307
308 /* recursively add alternates */
309 read_info_alternates(ent->base, depth + 1);
310
311 ent->base[pfxlen] = '/';
312
313 return 0;
314}
315
316static void link_alt_odb_entries(const char *alt, int len, int sep,
317 const char *relative_base, int depth)
318{
319 struct string_list entries = STRING_LIST_INIT_NODUP;
320 char *alt_copy;
321 int i;
322 struct strbuf objdirbuf = STRBUF_INIT;
323
324 if (depth > 5) {
325 error("%s: ignoring alternate object stores, nesting too deep.",
326 relative_base);
327 return;
328 }
329
330 strbuf_add_absolute_path(&objdirbuf, get_object_directory());
331 normalize_path_copy(objdirbuf.buf, objdirbuf.buf);
332
333 alt_copy = xmemdupz(alt, len);
334 string_list_split_in_place(&entries, alt_copy, sep, -1);
335 for (i = 0; i < entries.nr; i++) {
336 const char *entry = entries.items[i].string;
337 if (entry[0] == '\0' || entry[0] == '#')
338 continue;
339 if (!is_absolute_path(entry) && depth) {
340 error("%s: ignoring relative alternate object store %s",
341 relative_base, entry);
342 } else {
343 link_alt_odb_entry(entry, relative_base, depth, objdirbuf.buf);
344 }
345 }
346 string_list_clear(&entries, 0);
347 free(alt_copy);
348 strbuf_release(&objdirbuf);
349}
350
351void read_info_alternates(const char * relative_base, int depth)
352{
353 char *map;
354 size_t mapsz;
355 struct stat st;
356 char *path;
357 int fd;
358
359 path = xstrfmt("%s/info/alternates", relative_base);
360 fd = git_open_noatime(path);
361 free(path);
362 if (fd < 0)
363 return;
364 if (fstat(fd, &st) || (st.st_size == 0)) {
365 close(fd);
366 return;
367 }
368 mapsz = xsize_t(st.st_size);
369 map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
370 close(fd);
371
372 link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
373
374 munmap(map, mapsz);
375}
376
377void add_to_alternates_file(const char *reference)
378{
379 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
380 char *alts = git_pathdup("objects/info/alternates");
381 FILE *in, *out;
382
383 hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
384 out = fdopen_lock_file(lock, "w");
385 if (!out)
386 die_errno("unable to fdopen alternates lockfile");
387
388 in = fopen(alts, "r");
389 if (in) {
390 struct strbuf line = STRBUF_INIT;
391 int found = 0;
392
393 while (strbuf_getline(&line, in) != EOF) {
394 if (!strcmp(reference, line.buf)) {
395 found = 1;
396 break;
397 }
398 fprintf_or_die(out, "%s\n", line.buf);
399 }
400
401 strbuf_release(&line);
402 fclose(in);
403
404 if (found) {
405 rollback_lock_file(lock);
406 lock = NULL;
407 }
408 }
409 else if (errno != ENOENT)
410 die_errno("unable to read alternates file");
411
412 if (lock) {
413 fprintf_or_die(out, "%s\n", reference);
414 if (commit_lock_file(lock))
415 die_errno("unable to move new alternates file into place");
416 if (alt_odb_tail)
417 link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
418 }
419 free(alts);
420}
421
422int foreach_alt_odb(alt_odb_fn fn, void *cb)
423{
424 struct alternate_object_database *ent;
425 int r = 0;
426
427 prepare_alt_odb();
428 for (ent = alt_odb_list; ent; ent = ent->next) {
429 r = fn(ent, cb);
430 if (r)
431 break;
432 }
433 return r;
434}
435
436void prepare_alt_odb(void)
437{
438 const char *alt;
439
440 if (alt_odb_tail)
441 return;
442
443 alt = getenv(ALTERNATE_DB_ENVIRONMENT);
444 if (!alt) alt = "";
445
446 alt_odb_tail = &alt_odb_list;
447 link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
448
449 read_info_alternates(get_object_directory(), 0);
450}
451
452/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
453static int freshen_file(const char *fn)
454{
455 struct utimbuf t;
456 t.actime = t.modtime = time(NULL);
457 return !utime(fn, &t);
458}
459
460/*
461 * All of the check_and_freshen functions return 1 if the file exists and was
462 * freshened (if freshening was requested), 0 otherwise. If they return
463 * 0, you should not assume that it is safe to skip a write of the object (it
464 * either does not exist on disk, or has a stale mtime and may be subject to
465 * pruning).
466 */
467static int check_and_freshen_file(const char *fn, int freshen)
468{
469 if (access(fn, F_OK))
470 return 0;
471 if (freshen && !freshen_file(fn))
472 return 0;
473 return 1;
474}
475
476static int check_and_freshen_local(const unsigned char *sha1, int freshen)
477{
478 return check_and_freshen_file(sha1_file_name(sha1), freshen);
479}
480
481static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
482{
483 struct alternate_object_database *alt;
484 prepare_alt_odb();
485 for (alt = alt_odb_list; alt; alt = alt->next) {
486 fill_sha1_path(alt->name, sha1);
487 if (check_and_freshen_file(alt->base, freshen))
488 return 1;
489 }
490 return 0;
491}
492
493static int check_and_freshen(const unsigned char *sha1, int freshen)
494{
495 return check_and_freshen_local(sha1, freshen) ||
496 check_and_freshen_nonlocal(sha1, freshen);
497}
498
499int has_loose_object_nonlocal(const unsigned char *sha1)
500{
501 return check_and_freshen_nonlocal(sha1, 0);
502}
503
504static int has_loose_object(const unsigned char *sha1)
505{
506 return check_and_freshen(sha1, 0);
507}
508
509static unsigned int pack_used_ctr;
510static unsigned int pack_mmap_calls;
511static unsigned int peak_pack_open_windows;
512static unsigned int pack_open_windows;
513static unsigned int pack_open_fds;
514static unsigned int pack_max_fds;
515static size_t peak_pack_mapped;
516static size_t pack_mapped;
517struct packed_git *packed_git;
518
519static struct mru packed_git_mru_storage;
520struct mru *packed_git_mru = &packed_git_mru_storage;
521
522void pack_report(void)
523{
524 fprintf(stderr,
525 "pack_report: getpagesize() = %10" SZ_FMT "\n"
526 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
527 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
528 sz_fmt(getpagesize()),
529 sz_fmt(packed_git_window_size),
530 sz_fmt(packed_git_limit));
531 fprintf(stderr,
532 "pack_report: pack_used_ctr = %10u\n"
533 "pack_report: pack_mmap_calls = %10u\n"
534 "pack_report: pack_open_windows = %10u / %10u\n"
535 "pack_report: pack_mapped = "
536 "%10" SZ_FMT " / %10" SZ_FMT "\n",
537 pack_used_ctr,
538 pack_mmap_calls,
539 pack_open_windows, peak_pack_open_windows,
540 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
541}
542
543/*
544 * Open and mmap the index file at path, perform a couple of
545 * consistency checks, then record its information to p. Return 0 on
546 * success.
547 */
548static int check_packed_git_idx(const char *path, struct packed_git *p)
549{
550 void *idx_map;
551 struct pack_idx_header *hdr;
552 size_t idx_size;
553 uint32_t version, nr, i, *index;
554 int fd = git_open_noatime(path);
555 struct stat st;
556
557 if (fd < 0)
558 return -1;
559 if (fstat(fd, &st)) {
560 close(fd);
561 return -1;
562 }
563 idx_size = xsize_t(st.st_size);
564 if (idx_size < 4 * 256 + 20 + 20) {
565 close(fd);
566 return error("index file %s is too small", path);
567 }
568 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
569 close(fd);
570
571 hdr = idx_map;
572 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
573 version = ntohl(hdr->idx_version);
574 if (version < 2 || version > 2) {
575 munmap(idx_map, idx_size);
576 return error("index file %s is version %"PRIu32
577 " and is not supported by this binary"
578 " (try upgrading GIT to a newer version)",
579 path, version);
580 }
581 } else
582 version = 1;
583
584 nr = 0;
585 index = idx_map;
586 if (version > 1)
587 index += 2; /* skip index header */
588 for (i = 0; i < 256; i++) {
589 uint32_t n = ntohl(index[i]);
590 if (n < nr) {
591 munmap(idx_map, idx_size);
592 return error("non-monotonic index %s", path);
593 }
594 nr = n;
595 }
596
597 if (version == 1) {
598 /*
599 * Total size:
600 * - 256 index entries 4 bytes each
601 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
602 * - 20-byte SHA1 of the packfile
603 * - 20-byte SHA1 file checksum
604 */
605 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
606 munmap(idx_map, idx_size);
607 return error("wrong index v1 file size in %s", path);
608 }
609 } else if (version == 2) {
610 /*
611 * Minimum size:
612 * - 8 bytes of header
613 * - 256 index entries 4 bytes each
614 * - 20-byte sha1 entry * nr
615 * - 4-byte crc entry * nr
616 * - 4-byte offset entry * nr
617 * - 20-byte SHA1 of the packfile
618 * - 20-byte SHA1 file checksum
619 * And after the 4-byte offset table might be a
620 * variable sized table containing 8-byte entries
621 * for offsets larger than 2^31.
622 */
623 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
624 unsigned long max_size = min_size;
625 if (nr)
626 max_size += (nr - 1)*8;
627 if (idx_size < min_size || idx_size > max_size) {
628 munmap(idx_map, idx_size);
629 return error("wrong index v2 file size in %s", path);
630 }
631 if (idx_size != min_size &&
632 /*
633 * make sure we can deal with large pack offsets.
634 * 31-bit signed offset won't be enough, neither
635 * 32-bit unsigned one will be.
636 */
637 (sizeof(off_t) <= 4)) {
638 munmap(idx_map, idx_size);
639 return error("pack too large for current definition of off_t in %s", path);
640 }
641 }
642
643 p->index_version = version;
644 p->index_data = idx_map;
645 p->index_size = idx_size;
646 p->num_objects = nr;
647 return 0;
648}
649
650int open_pack_index(struct packed_git *p)
651{
652 char *idx_name;
653 size_t len;
654 int ret;
655
656 if (p->index_data)
657 return 0;
658
659 if (!strip_suffix(p->pack_name, ".pack", &len))
660 die("BUG: pack_name does not end in .pack");
661 idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
662 ret = check_packed_git_idx(idx_name, p);
663 free(idx_name);
664 return ret;
665}
666
667static void scan_windows(struct packed_git *p,
668 struct packed_git **lru_p,
669 struct pack_window **lru_w,
670 struct pack_window **lru_l)
671{
672 struct pack_window *w, *w_l;
673
674 for (w_l = NULL, w = p->windows; w; w = w->next) {
675 if (!w->inuse_cnt) {
676 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
677 *lru_p = p;
678 *lru_w = w;
679 *lru_l = w_l;
680 }
681 }
682 w_l = w;
683 }
684}
685
686static int unuse_one_window(struct packed_git *current)
687{
688 struct packed_git *p, *lru_p = NULL;
689 struct pack_window *lru_w = NULL, *lru_l = NULL;
690
691 if (current)
692 scan_windows(current, &lru_p, &lru_w, &lru_l);
693 for (p = packed_git; p; p = p->next)
694 scan_windows(p, &lru_p, &lru_w, &lru_l);
695 if (lru_p) {
696 munmap(lru_w->base, lru_w->len);
697 pack_mapped -= lru_w->len;
698 if (lru_l)
699 lru_l->next = lru_w->next;
700 else
701 lru_p->windows = lru_w->next;
702 free(lru_w);
703 pack_open_windows--;
704 return 1;
705 }
706 return 0;
707}
708
709void release_pack_memory(size_t need)
710{
711 size_t cur = pack_mapped;
712 while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
713 ; /* nothing */
714}
715
716static void mmap_limit_check(size_t length)
717{
718 static size_t limit = 0;
719 if (!limit) {
720 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
721 if (!limit)
722 limit = SIZE_MAX;
723 }
724 if (length > limit)
725 die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
726 (uintmax_t)length, (uintmax_t)limit);
727}
728
729void *xmmap_gently(void *start, size_t length,
730 int prot, int flags, int fd, off_t offset)
731{
732 void *ret;
733
734 mmap_limit_check(length);
735 ret = mmap(start, length, prot, flags, fd, offset);
736 if (ret == MAP_FAILED) {
737 if (!length)
738 return NULL;
739 release_pack_memory(length);
740 ret = mmap(start, length, prot, flags, fd, offset);
741 }
742 return ret;
743}
744
745void *xmmap(void *start, size_t length,
746 int prot, int flags, int fd, off_t offset)
747{
748 void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
749 if (ret == MAP_FAILED)
750 die_errno("mmap failed");
751 return ret;
752}
753
754void close_pack_windows(struct packed_git *p)
755{
756 while (p->windows) {
757 struct pack_window *w = p->windows;
758
759 if (w->inuse_cnt)
760 die("pack '%s' still has open windows to it",
761 p->pack_name);
762 munmap(w->base, w->len);
763 pack_mapped -= w->len;
764 pack_open_windows--;
765 p->windows = w->next;
766 free(w);
767 }
768}
769
770static int close_pack_fd(struct packed_git *p)
771{
772 if (p->pack_fd < 0)
773 return 0;
774
775 close(p->pack_fd);
776 pack_open_fds--;
777 p->pack_fd = -1;
778
779 return 1;
780}
781
782static void close_pack(struct packed_git *p)
783{
784 close_pack_windows(p);
785 close_pack_fd(p);
786 close_pack_index(p);
787}
788
789void close_all_packs(void)
790{
791 struct packed_git *p;
792
793 for (p = packed_git; p; p = p->next)
794 if (p->do_not_close)
795 die("BUG: want to close pack marked 'do-not-close'");
796 else
797 close_pack(p);
798}
799
800
801/*
802 * The LRU pack is the one with the oldest MRU window, preferring packs
803 * with no used windows, or the oldest mtime if it has no windows allocated.
804 */
805static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
806{
807 struct pack_window *w, *this_mru_w;
808 int has_windows_inuse = 0;
809
810 /*
811 * Reject this pack if it has windows and the previously selected
812 * one does not. If this pack does not have windows, reject
813 * it if the pack file is newer than the previously selected one.
814 */
815 if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
816 return;
817
818 for (w = this_mru_w = p->windows; w; w = w->next) {
819 /*
820 * Reject this pack if any of its windows are in use,
821 * but the previously selected pack did not have any
822 * inuse windows. Otherwise, record that this pack
823 * has windows in use.
824 */
825 if (w->inuse_cnt) {
826 if (*accept_windows_inuse)
827 has_windows_inuse = 1;
828 else
829 return;
830 }
831
832 if (w->last_used > this_mru_w->last_used)
833 this_mru_w = w;
834
835 /*
836 * Reject this pack if it has windows that have been
837 * used more recently than the previously selected pack.
838 * If the previously selected pack had windows inuse and
839 * we have not encountered a window in this pack that is
840 * inuse, skip this check since we prefer a pack with no
841 * inuse windows to one that has inuse windows.
842 */
843 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
844 this_mru_w->last_used > (*mru_w)->last_used)
845 return;
846 }
847
848 /*
849 * Select this pack.
850 */
851 *mru_w = this_mru_w;
852 *lru_p = p;
853 *accept_windows_inuse = has_windows_inuse;
854}
855
856static int close_one_pack(void)
857{
858 struct packed_git *p, *lru_p = NULL;
859 struct pack_window *mru_w = NULL;
860 int accept_windows_inuse = 1;
861
862 for (p = packed_git; p; p = p->next) {
863 if (p->pack_fd == -1)
864 continue;
865 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
866 }
867
868 if (lru_p)
869 return close_pack_fd(lru_p);
870
871 return 0;
872}
873
874void unuse_pack(struct pack_window **w_cursor)
875{
876 struct pack_window *w = *w_cursor;
877 if (w) {
878 w->inuse_cnt--;
879 *w_cursor = NULL;
880 }
881}
882
883void close_pack_index(struct packed_git *p)
884{
885 if (p->index_data) {
886 munmap((void *)p->index_data, p->index_size);
887 p->index_data = NULL;
888 }
889}
890
891static unsigned int get_max_fd_limit(void)
892{
893#ifdef RLIMIT_NOFILE
894 {
895 struct rlimit lim;
896
897 if (!getrlimit(RLIMIT_NOFILE, &lim))
898 return lim.rlim_cur;
899 }
900#endif
901
902#ifdef _SC_OPEN_MAX
903 {
904 long open_max = sysconf(_SC_OPEN_MAX);
905 if (0 < open_max)
906 return open_max;
907 /*
908 * Otherwise, we got -1 for one of the two
909 * reasons:
910 *
911 * (1) sysconf() did not understand _SC_OPEN_MAX
912 * and signaled an error with -1; or
913 * (2) sysconf() said there is no limit.
914 *
915 * We _could_ clear errno before calling sysconf() to
916 * tell these two cases apart and return a huge number
917 * in the latter case to let the caller cap it to a
918 * value that is not so selfish, but letting the
919 * fallback OPEN_MAX codepath take care of these cases
920 * is a lot simpler.
921 */
922 }
923#endif
924
925#ifdef OPEN_MAX
926 return OPEN_MAX;
927#else
928 return 1; /* see the caller ;-) */
929#endif
930}
931
932/*
933 * Do not call this directly as this leaks p->pack_fd on error return;
934 * call open_packed_git() instead.
935 */
936static int open_packed_git_1(struct packed_git *p)
937{
938 struct stat st;
939 struct pack_header hdr;
940 unsigned char sha1[20];
941 unsigned char *idx_sha1;
942 long fd_flag;
943
944 if (!p->index_data && open_pack_index(p))
945 return error("packfile %s index unavailable", p->pack_name);
946
947 if (!pack_max_fds) {
948 unsigned int max_fds = get_max_fd_limit();
949
950 /* Save 3 for stdin/stdout/stderr, 22 for work */
951 if (25 < max_fds)
952 pack_max_fds = max_fds - 25;
953 else
954 pack_max_fds = 1;
955 }
956
957 while (pack_max_fds <= pack_open_fds && close_one_pack())
958 ; /* nothing */
959
960 p->pack_fd = git_open_noatime(p->pack_name);
961 if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
962 return -1;
963 pack_open_fds++;
964
965 /* If we created the struct before we had the pack we lack size. */
966 if (!p->pack_size) {
967 if (!S_ISREG(st.st_mode))
968 return error("packfile %s not a regular file", p->pack_name);
969 p->pack_size = st.st_size;
970 } else if (p->pack_size != st.st_size)
971 return error("packfile %s size changed", p->pack_name);
972
973 /* We leave these file descriptors open with sliding mmap;
974 * there is no point keeping them open across exec(), though.
975 */
976 fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
977 if (fd_flag < 0)
978 return error("cannot determine file descriptor flags");
979 fd_flag |= FD_CLOEXEC;
980 if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
981 return error("cannot set FD_CLOEXEC");
982
983 /* Verify we recognize this pack file format. */
984 if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
985 return error("file %s is far too short to be a packfile", p->pack_name);
986 if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
987 return error("file %s is not a GIT packfile", p->pack_name);
988 if (!pack_version_ok(hdr.hdr_version))
989 return error("packfile %s is version %"PRIu32" and not"
990 " supported (try upgrading GIT to a newer version)",
991 p->pack_name, ntohl(hdr.hdr_version));
992
993 /* Verify the pack matches its index. */
994 if (p->num_objects != ntohl(hdr.hdr_entries))
995 return error("packfile %s claims to have %"PRIu32" objects"
996 " while index indicates %"PRIu32" objects",
997 p->pack_name, ntohl(hdr.hdr_entries),
998 p->num_objects);
999 if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
1000 return error("end of packfile %s is unavailable", p->pack_name);
1001 if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
1002 return error("packfile %s signature is unavailable", p->pack_name);
1003 idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
1004 if (hashcmp(sha1, idx_sha1))
1005 return error("packfile %s does not match index", p->pack_name);
1006 return 0;
1007}
1008
1009static int open_packed_git(struct packed_git *p)
1010{
1011 if (!open_packed_git_1(p))
1012 return 0;
1013 close_pack_fd(p);
1014 return -1;
1015}
1016
1017static int in_window(struct pack_window *win, off_t offset)
1018{
1019 /* We must promise at least 20 bytes (one hash) after the
1020 * offset is available from this window, otherwise the offset
1021 * is not actually in this window and a different window (which
1022 * has that one hash excess) must be used. This is to support
1023 * the object header and delta base parsing routines below.
1024 */
1025 off_t win_off = win->offset;
1026 return win_off <= offset
1027 && (offset + 20) <= (win_off + win->len);
1028}
1029
1030unsigned char *use_pack(struct packed_git *p,
1031 struct pack_window **w_cursor,
1032 off_t offset,
1033 unsigned long *left)
1034{
1035 struct pack_window *win = *w_cursor;
1036
1037 /* Since packfiles end in a hash of their content and it's
1038 * pointless to ask for an offset into the middle of that
1039 * hash, and the in_window function above wouldn't match
1040 * don't allow an offset too close to the end of the file.
1041 */
1042 if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
1043 die("packfile %s cannot be accessed", p->pack_name);
1044 if (offset > (p->pack_size - 20))
1045 die("offset beyond end of packfile (truncated pack?)");
1046 if (offset < 0)
1047 die(_("offset before end of packfile (broken .idx?)"));
1048
1049 if (!win || !in_window(win, offset)) {
1050 if (win)
1051 win->inuse_cnt--;
1052 for (win = p->windows; win; win = win->next) {
1053 if (in_window(win, offset))
1054 break;
1055 }
1056 if (!win) {
1057 size_t window_align = packed_git_window_size / 2;
1058 off_t len;
1059
1060 if (p->pack_fd == -1 && open_packed_git(p))
1061 die("packfile %s cannot be accessed", p->pack_name);
1062
1063 win = xcalloc(1, sizeof(*win));
1064 win->offset = (offset / window_align) * window_align;
1065 len = p->pack_size - win->offset;
1066 if (len > packed_git_window_size)
1067 len = packed_git_window_size;
1068 win->len = (size_t)len;
1069 pack_mapped += win->len;
1070 while (packed_git_limit < pack_mapped
1071 && unuse_one_window(p))
1072 ; /* nothing */
1073 win->base = xmmap(NULL, win->len,
1074 PROT_READ, MAP_PRIVATE,
1075 p->pack_fd, win->offset);
1076 if (win->base == MAP_FAILED)
1077 die_errno("packfile %s cannot be mapped",
1078 p->pack_name);
1079 if (!win->offset && win->len == p->pack_size
1080 && !p->do_not_close)
1081 close_pack_fd(p);
1082 pack_mmap_calls++;
1083 pack_open_windows++;
1084 if (pack_mapped > peak_pack_mapped)
1085 peak_pack_mapped = pack_mapped;
1086 if (pack_open_windows > peak_pack_open_windows)
1087 peak_pack_open_windows = pack_open_windows;
1088 win->next = p->windows;
1089 p->windows = win;
1090 }
1091 }
1092 if (win != *w_cursor) {
1093 win->last_used = pack_used_ctr++;
1094 win->inuse_cnt++;
1095 *w_cursor = win;
1096 }
1097 offset -= win->offset;
1098 if (left)
1099 *left = win->len - xsize_t(offset);
1100 return win->base + offset;
1101}
1102
1103static struct packed_git *alloc_packed_git(int extra)
1104{
1105 struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
1106 memset(p, 0, sizeof(*p));
1107 p->pack_fd = -1;
1108 return p;
1109}
1110
1111static void try_to_free_pack_memory(size_t size)
1112{
1113 release_pack_memory(size);
1114}
1115
1116struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
1117{
1118 static int have_set_try_to_free_routine;
1119 struct stat st;
1120 size_t alloc;
1121 struct packed_git *p;
1122
1123 if (!have_set_try_to_free_routine) {
1124 have_set_try_to_free_routine = 1;
1125 set_try_to_free_routine(try_to_free_pack_memory);
1126 }
1127
1128 /*
1129 * Make sure a corresponding .pack file exists and that
1130 * the index looks sane.
1131 */
1132 if (!strip_suffix_mem(path, &path_len, ".idx"))
1133 return NULL;
1134
1135 /*
1136 * ".pack" is long enough to hold any suffix we're adding (and
1137 * the use xsnprintf double-checks that)
1138 */
1139 alloc = st_add3(path_len, strlen(".pack"), 1);
1140 p = alloc_packed_git(alloc);
1141 memcpy(p->pack_name, path, path_len);
1142
1143 xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
1144 if (!access(p->pack_name, F_OK))
1145 p->pack_keep = 1;
1146
1147 xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
1148 if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
1149 free(p);
1150 return NULL;
1151 }
1152
1153 /* ok, it looks sane as far as we can check without
1154 * actually mapping the pack file.
1155 */
1156 p->pack_size = st.st_size;
1157 p->pack_local = local;
1158 p->mtime = st.st_mtime;
1159 if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
1160 hashclr(p->sha1);
1161 return p;
1162}
1163
1164struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
1165{
1166 const char *path = sha1_pack_name(sha1);
1167 size_t alloc = st_add(strlen(path), 1);
1168 struct packed_git *p = alloc_packed_git(alloc);
1169
1170 memcpy(p->pack_name, path, alloc); /* includes NUL */
1171 hashcpy(p->sha1, sha1);
1172 if (check_packed_git_idx(idx_path, p)) {
1173 free(p);
1174 return NULL;
1175 }
1176
1177 return p;
1178}
1179
1180void install_packed_git(struct packed_git *pack)
1181{
1182 if (pack->pack_fd != -1)
1183 pack_open_fds++;
1184
1185 pack->next = packed_git;
1186 packed_git = pack;
1187}
1188
1189void (*report_garbage)(unsigned seen_bits, const char *path);
1190
1191static void report_helper(const struct string_list *list,
1192 int seen_bits, int first, int last)
1193{
1194 if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
1195 return;
1196
1197 for (; first < last; first++)
1198 report_garbage(seen_bits, list->items[first].string);
1199}
1200
1201static void report_pack_garbage(struct string_list *list)
1202{
1203 int i, baselen = -1, first = 0, seen_bits = 0;
1204
1205 if (!report_garbage)
1206 return;
1207
1208 string_list_sort(list);
1209
1210 for (i = 0; i < list->nr; i++) {
1211 const char *path = list->items[i].string;
1212 if (baselen != -1 &&
1213 strncmp(path, list->items[first].string, baselen)) {
1214 report_helper(list, seen_bits, first, i);
1215 baselen = -1;
1216 seen_bits = 0;
1217 }
1218 if (baselen == -1) {
1219 const char *dot = strrchr(path, '.');
1220 if (!dot) {
1221 report_garbage(PACKDIR_FILE_GARBAGE, path);
1222 continue;
1223 }
1224 baselen = dot - path + 1;
1225 first = i;
1226 }
1227 if (!strcmp(path + baselen, "pack"))
1228 seen_bits |= 1;
1229 else if (!strcmp(path + baselen, "idx"))
1230 seen_bits |= 2;
1231 }
1232 report_helper(list, seen_bits, first, list->nr);
1233}
1234
1235static void prepare_packed_git_one(char *objdir, int local)
1236{
1237 struct strbuf path = STRBUF_INIT;
1238 size_t dirnamelen;
1239 DIR *dir;
1240 struct dirent *de;
1241 struct string_list garbage = STRING_LIST_INIT_DUP;
1242
1243 strbuf_addstr(&path, objdir);
1244 strbuf_addstr(&path, "/pack");
1245 dir = opendir(path.buf);
1246 if (!dir) {
1247 if (errno != ENOENT)
1248 error_errno("unable to open object pack directory: %s",
1249 path.buf);
1250 strbuf_release(&path);
1251 return;
1252 }
1253 strbuf_addch(&path, '/');
1254 dirnamelen = path.len;
1255 while ((de = readdir(dir)) != NULL) {
1256 struct packed_git *p;
1257 size_t base_len;
1258
1259 if (is_dot_or_dotdot(de->d_name))
1260 continue;
1261
1262 strbuf_setlen(&path, dirnamelen);
1263 strbuf_addstr(&path, de->d_name);
1264
1265 base_len = path.len;
1266 if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
1267 /* Don't reopen a pack we already have. */
1268 for (p = packed_git; p; p = p->next) {
1269 size_t len;
1270 if (strip_suffix(p->pack_name, ".pack", &len) &&
1271 len == base_len &&
1272 !memcmp(p->pack_name, path.buf, len))
1273 break;
1274 }
1275 if (p == NULL &&
1276 /*
1277 * See if it really is a valid .idx file with
1278 * corresponding .pack file that we can map.
1279 */
1280 (p = add_packed_git(path.buf, path.len, local)) != NULL)
1281 install_packed_git(p);
1282 }
1283
1284 if (!report_garbage)
1285 continue;
1286
1287 if (ends_with(de->d_name, ".idx") ||
1288 ends_with(de->d_name, ".pack") ||
1289 ends_with(de->d_name, ".bitmap") ||
1290 ends_with(de->d_name, ".keep"))
1291 string_list_append(&garbage, path.buf);
1292 else
1293 report_garbage(PACKDIR_FILE_GARBAGE, path.buf);
1294 }
1295 closedir(dir);
1296 report_pack_garbage(&garbage);
1297 string_list_clear(&garbage, 0);
1298 strbuf_release(&path);
1299}
1300
1301static int sort_pack(const void *a_, const void *b_)
1302{
1303 struct packed_git *a = *((struct packed_git **)a_);
1304 struct packed_git *b = *((struct packed_git **)b_);
1305 int st;
1306
1307 /*
1308 * Local packs tend to contain objects specific to our
1309 * variant of the project than remote ones. In addition,
1310 * remote ones could be on a network mounted filesystem.
1311 * Favor local ones for these reasons.
1312 */
1313 st = a->pack_local - b->pack_local;
1314 if (st)
1315 return -st;
1316
1317 /*
1318 * Younger packs tend to contain more recent objects,
1319 * and more recent objects tend to get accessed more
1320 * often.
1321 */
1322 if (a->mtime < b->mtime)
1323 return 1;
1324 else if (a->mtime == b->mtime)
1325 return 0;
1326 return -1;
1327}
1328
1329static void rearrange_packed_git(void)
1330{
1331 struct packed_git **ary, *p;
1332 int i, n;
1333
1334 for (n = 0, p = packed_git; p; p = p->next)
1335 n++;
1336 if (n < 2)
1337 return;
1338
1339 /* prepare an array of packed_git for easier sorting */
1340 ary = xcalloc(n, sizeof(struct packed_git *));
1341 for (n = 0, p = packed_git; p; p = p->next)
1342 ary[n++] = p;
1343
1344 qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1345
1346 /* link them back again */
1347 for (i = 0; i < n - 1; i++)
1348 ary[i]->next = ary[i + 1];
1349 ary[n - 1]->next = NULL;
1350 packed_git = ary[0];
1351
1352 free(ary);
1353}
1354
1355static void prepare_packed_git_mru(void)
1356{
1357 struct packed_git *p;
1358
1359 mru_clear(packed_git_mru);
1360 for (p = packed_git; p; p = p->next)
1361 mru_append(packed_git_mru, p);
1362}
1363
1364static int prepare_packed_git_run_once = 0;
1365void prepare_packed_git(void)
1366{
1367 struct alternate_object_database *alt;
1368
1369 if (prepare_packed_git_run_once)
1370 return;
1371 prepare_packed_git_one(get_object_directory(), 1);
1372 prepare_alt_odb();
1373 for (alt = alt_odb_list; alt; alt = alt->next) {
1374 alt->name[-1] = 0;
1375 prepare_packed_git_one(alt->base, 0);
1376 alt->name[-1] = '/';
1377 }
1378 rearrange_packed_git();
1379 prepare_packed_git_mru();
1380 prepare_packed_git_run_once = 1;
1381}
1382
1383void reprepare_packed_git(void)
1384{
1385 prepare_packed_git_run_once = 0;
1386 prepare_packed_git();
1387}
1388
1389static void mark_bad_packed_object(struct packed_git *p,
1390 const unsigned char *sha1)
1391{
1392 unsigned i;
1393 for (i = 0; i < p->num_bad_objects; i++)
1394 if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
1395 return;
1396 p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1397 st_mult(GIT_SHA1_RAWSZ,
1398 st_add(p->num_bad_objects, 1)));
1399 hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
1400 p->num_bad_objects++;
1401}
1402
1403static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1404{
1405 struct packed_git *p;
1406 unsigned i;
1407
1408 for (p = packed_git; p; p = p->next)
1409 for (i = 0; i < p->num_bad_objects; i++)
1410 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1411 return p;
1412 return NULL;
1413}
1414
1415/*
1416 * With an in-core object data in "map", rehash it to make sure the
1417 * object name actually matches "sha1" to detect object corruption.
1418 * With "map" == NULL, try reading the object named with "sha1" using
1419 * the streaming interface and rehash it to do the same.
1420 */
1421int check_sha1_signature(const unsigned char *sha1, void *map,
1422 unsigned long size, const char *type)
1423{
1424 unsigned char real_sha1[20];
1425 enum object_type obj_type;
1426 struct git_istream *st;
1427 git_SHA_CTX c;
1428 char hdr[32];
1429 int hdrlen;
1430
1431 if (map) {
1432 hash_sha1_file(map, size, type, real_sha1);
1433 return hashcmp(sha1, real_sha1) ? -1 : 0;
1434 }
1435
1436 st = open_istream(sha1, &obj_type, &size, NULL);
1437 if (!st)
1438 return -1;
1439
1440 /* Generate the header */
1441 hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
1442
1443 /* Sha1.. */
1444 git_SHA1_Init(&c);
1445 git_SHA1_Update(&c, hdr, hdrlen);
1446 for (;;) {
1447 char buf[1024 * 16];
1448 ssize_t readlen = read_istream(st, buf, sizeof(buf));
1449
1450 if (readlen < 0) {
1451 close_istream(st);
1452 return -1;
1453 }
1454 if (!readlen)
1455 break;
1456 git_SHA1_Update(&c, buf, readlen);
1457 }
1458 git_SHA1_Final(real_sha1, &c);
1459 close_istream(st);
1460 return hashcmp(sha1, real_sha1) ? -1 : 0;
1461}
1462
1463int git_open_noatime(const char *name)
1464{
1465 static int sha1_file_open_flag = O_NOATIME;
1466
1467 for (;;) {
1468 int fd;
1469
1470 errno = 0;
1471 fd = open(name, O_RDONLY | sha1_file_open_flag);
1472 if (fd >= 0)
1473 return fd;
1474
1475 /* Might the failure be due to O_NOATIME? */
1476 if (errno != ENOENT && sha1_file_open_flag) {
1477 sha1_file_open_flag = 0;
1478 continue;
1479 }
1480
1481 return -1;
1482 }
1483}
1484
1485static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
1486{
1487 struct alternate_object_database *alt;
1488
1489 if (!lstat(sha1_file_name(sha1), st))
1490 return 0;
1491
1492 prepare_alt_odb();
1493 errno = ENOENT;
1494 for (alt = alt_odb_list; alt; alt = alt->next) {
1495 fill_sha1_path(alt->name, sha1);
1496 if (!lstat(alt->base, st))
1497 return 0;
1498 }
1499
1500 return -1;
1501}
1502
1503static int open_sha1_file(const unsigned char *sha1)
1504{
1505 int fd;
1506 struct alternate_object_database *alt;
1507 int most_interesting_errno;
1508
1509 fd = git_open_noatime(sha1_file_name(sha1));
1510 if (fd >= 0)
1511 return fd;
1512 most_interesting_errno = errno;
1513
1514 prepare_alt_odb();
1515 for (alt = alt_odb_list; alt; alt = alt->next) {
1516 fill_sha1_path(alt->name, sha1);
1517 fd = git_open_noatime(alt->base);
1518 if (fd >= 0)
1519 return fd;
1520 if (most_interesting_errno == ENOENT)
1521 most_interesting_errno = errno;
1522 }
1523 errno = most_interesting_errno;
1524 return -1;
1525}
1526
1527void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1528{
1529 void *map;
1530 int fd;
1531
1532 fd = open_sha1_file(sha1);
1533 map = NULL;
1534 if (fd >= 0) {
1535 struct stat st;
1536
1537 if (!fstat(fd, &st)) {
1538 *size = xsize_t(st.st_size);
1539 if (!*size) {
1540 /* mmap() is forbidden on empty files */
1541 error("object file %s is empty", sha1_file_name(sha1));
1542 return NULL;
1543 }
1544 map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1545 }
1546 close(fd);
1547 }
1548 return map;
1549}
1550
1551unsigned long unpack_object_header_buffer(const unsigned char *buf,
1552 unsigned long len, enum object_type *type, unsigned long *sizep)
1553{
1554 unsigned shift;
1555 unsigned long size, c;
1556 unsigned long used = 0;
1557
1558 c = buf[used++];
1559 *type = (c >> 4) & 7;
1560 size = c & 15;
1561 shift = 4;
1562 while (c & 0x80) {
1563 if (len <= used || bitsizeof(long) <= shift) {
1564 error("bad object header");
1565 size = used = 0;
1566 break;
1567 }
1568 c = buf[used++];
1569 size += (c & 0x7f) << shift;
1570 shift += 7;
1571 }
1572 *sizep = size;
1573 return used;
1574}
1575
1576int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1577{
1578 /* Get the data stream */
1579 memset(stream, 0, sizeof(*stream));
1580 stream->next_in = map;
1581 stream->avail_in = mapsize;
1582 stream->next_out = buffer;
1583 stream->avail_out = bufsiz;
1584
1585 git_inflate_init(stream);
1586 return git_inflate(stream, 0);
1587}
1588
1589static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
1590 unsigned long mapsize, void *buffer,
1591 unsigned long bufsiz, struct strbuf *header)
1592{
1593 int status;
1594
1595 status = unpack_sha1_header(stream, map, mapsize, buffer, bufsiz);
1596
1597 /*
1598 * Check if entire header is unpacked in the first iteration.
1599 */
1600 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1601 return 0;
1602
1603 /*
1604 * buffer[0..bufsiz] was not large enough. Copy the partial
1605 * result out to header, and then append the result of further
1606 * reading the stream.
1607 */
1608 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1609 stream->next_out = buffer;
1610 stream->avail_out = bufsiz;
1611
1612 do {
1613 status = git_inflate(stream, 0);
1614 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1615 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1616 return 0;
1617 stream->next_out = buffer;
1618 stream->avail_out = bufsiz;
1619 } while (status != Z_STREAM_END);
1620 return -1;
1621}
1622
1623static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1624{
1625 int bytes = strlen(buffer) + 1;
1626 unsigned char *buf = xmallocz(size);
1627 unsigned long n;
1628 int status = Z_OK;
1629
1630 n = stream->total_out - bytes;
1631 if (n > size)
1632 n = size;
1633 memcpy(buf, (char *) buffer + bytes, n);
1634 bytes = n;
1635 if (bytes <= size) {
1636 /*
1637 * The above condition must be (bytes <= size), not
1638 * (bytes < size). In other words, even though we
1639 * expect no more output and set avail_out to zero,
1640 * the input zlib stream may have bytes that express
1641 * "this concludes the stream", and we *do* want to
1642 * eat that input.
1643 *
1644 * Otherwise we would not be able to test that we
1645 * consumed all the input to reach the expected size;
1646 * we also want to check that zlib tells us that all
1647 * went well with status == Z_STREAM_END at the end.
1648 */
1649 stream->next_out = buf + bytes;
1650 stream->avail_out = size - bytes;
1651 while (status == Z_OK)
1652 status = git_inflate(stream, Z_FINISH);
1653 }
1654 if (status == Z_STREAM_END && !stream->avail_in) {
1655 git_inflate_end(stream);
1656 return buf;
1657 }
1658
1659 if (status < 0)
1660 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1661 else if (stream->avail_in)
1662 error("garbage at end of loose object '%s'",
1663 sha1_to_hex(sha1));
1664 free(buf);
1665 return NULL;
1666}
1667
1668/*
1669 * We used to just use "sscanf()", but that's actually way
1670 * too permissive for what we want to check. So do an anal
1671 * object header parse by hand.
1672 */
1673static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1674 unsigned int flags)
1675{
1676 const char *type_buf = hdr;
1677 unsigned long size;
1678 int type, type_len = 0;
1679
1680 /*
1681 * The type can be of any size but is followed by
1682 * a space.
1683 */
1684 for (;;) {
1685 char c = *hdr++;
1686 if (c == ' ')
1687 break;
1688 type_len++;
1689 }
1690
1691 type = type_from_string_gently(type_buf, type_len, 1);
1692 if (oi->typename)
1693 strbuf_add(oi->typename, type_buf, type_len);
1694 /*
1695 * Set type to 0 if its an unknown object and
1696 * we're obtaining the type using '--allow-unknown-type'
1697 * option.
1698 */
1699 if ((flags & LOOKUP_UNKNOWN_OBJECT) && (type < 0))
1700 type = 0;
1701 else if (type < 0)
1702 die("invalid object type");
1703 if (oi->typep)
1704 *oi->typep = type;
1705
1706 /*
1707 * The length must follow immediately, and be in canonical
1708 * decimal format (ie "010" is not valid).
1709 */
1710 size = *hdr++ - '0';
1711 if (size > 9)
1712 return -1;
1713 if (size) {
1714 for (;;) {
1715 unsigned long c = *hdr - '0';
1716 if (c > 9)
1717 break;
1718 hdr++;
1719 size = size * 10 + c;
1720 }
1721 }
1722
1723 if (oi->sizep)
1724 *oi->sizep = size;
1725
1726 /*
1727 * The length must be followed by a zero byte
1728 */
1729 return *hdr ? -1 : type;
1730}
1731
1732int parse_sha1_header(const char *hdr, unsigned long *sizep)
1733{
1734 struct object_info oi;
1735
1736 oi.sizep = sizep;
1737 oi.typename = NULL;
1738 oi.typep = NULL;
1739 return parse_sha1_header_extended(hdr, &oi, LOOKUP_REPLACE_OBJECT);
1740}
1741
1742static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1743{
1744 int ret;
1745 git_zstream stream;
1746 char hdr[8192];
1747
1748 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1749 if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1750 return NULL;
1751
1752 return unpack_sha1_rest(&stream, hdr, *size, sha1);
1753}
1754
1755unsigned long get_size_from_delta(struct packed_git *p,
1756 struct pack_window **w_curs,
1757 off_t curpos)
1758{
1759 const unsigned char *data;
1760 unsigned char delta_head[20], *in;
1761 git_zstream stream;
1762 int st;
1763
1764 memset(&stream, 0, sizeof(stream));
1765 stream.next_out = delta_head;
1766 stream.avail_out = sizeof(delta_head);
1767
1768 git_inflate_init(&stream);
1769 do {
1770 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1771 stream.next_in = in;
1772 st = git_inflate(&stream, Z_FINISH);
1773 curpos += stream.next_in - in;
1774 } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1775 stream.total_out < sizeof(delta_head));
1776 git_inflate_end(&stream);
1777 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1778 error("delta data unpack-initial failed");
1779 return 0;
1780 }
1781
1782 /* Examine the initial part of the delta to figure out
1783 * the result size.
1784 */
1785 data = delta_head;
1786
1787 /* ignore base size */
1788 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1789
1790 /* Read the result size */
1791 return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1792}
1793
1794static off_t get_delta_base(struct packed_git *p,
1795 struct pack_window **w_curs,
1796 off_t *curpos,
1797 enum object_type type,
1798 off_t delta_obj_offset)
1799{
1800 unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1801 off_t base_offset;
1802
1803 /* use_pack() assured us we have [base_info, base_info + 20)
1804 * as a range that we can look at without walking off the
1805 * end of the mapped window. Its actually the hash size
1806 * that is assured. An OFS_DELTA longer than the hash size
1807 * is stupid, as then a REF_DELTA would be smaller to store.
1808 */
1809 if (type == OBJ_OFS_DELTA) {
1810 unsigned used = 0;
1811 unsigned char c = base_info[used++];
1812 base_offset = c & 127;
1813 while (c & 128) {
1814 base_offset += 1;
1815 if (!base_offset || MSB(base_offset, 7))
1816 return 0; /* overflow */
1817 c = base_info[used++];
1818 base_offset = (base_offset << 7) + (c & 127);
1819 }
1820 base_offset = delta_obj_offset - base_offset;
1821 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1822 return 0; /* out of bound */
1823 *curpos += used;
1824 } else if (type == OBJ_REF_DELTA) {
1825 /* The base entry _must_ be in the same pack */
1826 base_offset = find_pack_entry_one(base_info, p);
1827 *curpos += 20;
1828 } else
1829 die("I am totally screwed");
1830 return base_offset;
1831}
1832
1833/*
1834 * Like get_delta_base above, but we return the sha1 instead of the pack
1835 * offset. This means it is cheaper for REF deltas (we do not have to do
1836 * the final object lookup), but more expensive for OFS deltas (we
1837 * have to load the revidx to convert the offset back into a sha1).
1838 */
1839static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1840 struct pack_window **w_curs,
1841 off_t curpos,
1842 enum object_type type,
1843 off_t delta_obj_offset)
1844{
1845 if (type == OBJ_REF_DELTA) {
1846 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1847 return base;
1848 } else if (type == OBJ_OFS_DELTA) {
1849 struct revindex_entry *revidx;
1850 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1851 type, delta_obj_offset);
1852
1853 if (!base_offset)
1854 return NULL;
1855
1856 revidx = find_pack_revindex(p, base_offset);
1857 if (!revidx)
1858 return NULL;
1859
1860 return nth_packed_object_sha1(p, revidx->nr);
1861 } else
1862 return NULL;
1863}
1864
1865int unpack_object_header(struct packed_git *p,
1866 struct pack_window **w_curs,
1867 off_t *curpos,
1868 unsigned long *sizep)
1869{
1870 unsigned char *base;
1871 unsigned long left;
1872 unsigned long used;
1873 enum object_type type;
1874
1875 /* use_pack() assures us we have [base, base + 20) available
1876 * as a range that we can look at. (Its actually the hash
1877 * size that is assured.) With our object header encoding
1878 * the maximum deflated object size is 2^137, which is just
1879 * insane, so we know won't exceed what we have been given.
1880 */
1881 base = use_pack(p, w_curs, *curpos, &left);
1882 used = unpack_object_header_buffer(base, left, &type, sizep);
1883 if (!used) {
1884 type = OBJ_BAD;
1885 } else
1886 *curpos += used;
1887
1888 return type;
1889}
1890
1891static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
1892{
1893 int type;
1894 struct revindex_entry *revidx;
1895 const unsigned char *sha1;
1896 revidx = find_pack_revindex(p, obj_offset);
1897 if (!revidx)
1898 return OBJ_BAD;
1899 sha1 = nth_packed_object_sha1(p, revidx->nr);
1900 mark_bad_packed_object(p, sha1);
1901 type = sha1_object_info(sha1, NULL);
1902 if (type <= OBJ_NONE)
1903 return OBJ_BAD;
1904 return type;
1905}
1906
1907#define POI_STACK_PREALLOC 64
1908
1909static enum object_type packed_to_object_type(struct packed_git *p,
1910 off_t obj_offset,
1911 enum object_type type,
1912 struct pack_window **w_curs,
1913 off_t curpos)
1914{
1915 off_t small_poi_stack[POI_STACK_PREALLOC];
1916 off_t *poi_stack = small_poi_stack;
1917 int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1918
1919 while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1920 off_t base_offset;
1921 unsigned long size;
1922 /* Push the object we're going to leave behind */
1923 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1924 poi_stack_alloc = alloc_nr(poi_stack_nr);
1925 ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1926 memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1927 } else {
1928 ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1929 }
1930 poi_stack[poi_stack_nr++] = obj_offset;
1931 /* If parsing the base offset fails, just unwind */
1932 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1933 if (!base_offset)
1934 goto unwind;
1935 curpos = obj_offset = base_offset;
1936 type = unpack_object_header(p, w_curs, &curpos, &size);
1937 if (type <= OBJ_NONE) {
1938 /* If getting the base itself fails, we first
1939 * retry the base, otherwise unwind */
1940 type = retry_bad_packed_offset(p, base_offset);
1941 if (type > OBJ_NONE)
1942 goto out;
1943 goto unwind;
1944 }
1945 }
1946
1947 switch (type) {
1948 case OBJ_BAD:
1949 case OBJ_COMMIT:
1950 case OBJ_TREE:
1951 case OBJ_BLOB:
1952 case OBJ_TAG:
1953 break;
1954 default:
1955 error("unknown object type %i at offset %"PRIuMAX" in %s",
1956 type, (uintmax_t)obj_offset, p->pack_name);
1957 type = OBJ_BAD;
1958 }
1959
1960out:
1961 if (poi_stack != small_poi_stack)
1962 free(poi_stack);
1963 return type;
1964
1965unwind:
1966 while (poi_stack_nr) {
1967 obj_offset = poi_stack[--poi_stack_nr];
1968 type = retry_bad_packed_offset(p, obj_offset);
1969 if (type > OBJ_NONE)
1970 goto out;
1971 }
1972 type = OBJ_BAD;
1973 goto out;
1974}
1975
1976static int packed_object_info(struct packed_git *p, off_t obj_offset,
1977 struct object_info *oi)
1978{
1979 struct pack_window *w_curs = NULL;
1980 unsigned long size;
1981 off_t curpos = obj_offset;
1982 enum object_type type;
1983
1984 /*
1985 * We always get the representation type, but only convert it to
1986 * a "real" type later if the caller is interested.
1987 */
1988 type = unpack_object_header(p, &w_curs, &curpos, &size);
1989
1990 if (oi->sizep) {
1991 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1992 off_t tmp_pos = curpos;
1993 off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1994 type, obj_offset);
1995 if (!base_offset) {
1996 type = OBJ_BAD;
1997 goto out;
1998 }
1999 *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
2000 if (*oi->sizep == 0) {
2001 type = OBJ_BAD;
2002 goto out;
2003 }
2004 } else {
2005 *oi->sizep = size;
2006 }
2007 }
2008
2009 if (oi->disk_sizep) {
2010 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2011 *oi->disk_sizep = revidx[1].offset - obj_offset;
2012 }
2013
2014 if (oi->typep) {
2015 *oi->typep = packed_to_object_type(p, obj_offset, type, &w_curs, curpos);
2016 if (*oi->typep < 0) {
2017 type = OBJ_BAD;
2018 goto out;
2019 }
2020 }
2021
2022 if (oi->delta_base_sha1) {
2023 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
2024 const unsigned char *base;
2025
2026 base = get_delta_base_sha1(p, &w_curs, curpos,
2027 type, obj_offset);
2028 if (!base) {
2029 type = OBJ_BAD;
2030 goto out;
2031 }
2032
2033 hashcpy(oi->delta_base_sha1, base);
2034 } else
2035 hashclr(oi->delta_base_sha1);
2036 }
2037
2038out:
2039 unuse_pack(&w_curs);
2040 return type;
2041}
2042
2043static void *unpack_compressed_entry(struct packed_git *p,
2044 struct pack_window **w_curs,
2045 off_t curpos,
2046 unsigned long size)
2047{
2048 int st;
2049 git_zstream stream;
2050 unsigned char *buffer, *in;
2051
2052 buffer = xmallocz_gently(size);
2053 if (!buffer)
2054 return NULL;
2055 memset(&stream, 0, sizeof(stream));
2056 stream.next_out = buffer;
2057 stream.avail_out = size + 1;
2058
2059 git_inflate_init(&stream);
2060 do {
2061 in = use_pack(p, w_curs, curpos, &stream.avail_in);
2062 stream.next_in = in;
2063 st = git_inflate(&stream, Z_FINISH);
2064 if (!stream.avail_out)
2065 break; /* the payload is larger than it should be */
2066 curpos += stream.next_in - in;
2067 } while (st == Z_OK || st == Z_BUF_ERROR);
2068 git_inflate_end(&stream);
2069 if ((st != Z_STREAM_END) || stream.total_out != size) {
2070 free(buffer);
2071 return NULL;
2072 }
2073
2074 return buffer;
2075}
2076
2077#define MAX_DELTA_CACHE (256)
2078
2079static size_t delta_base_cached;
2080
2081static LIST_HEAD(delta_base_cache_lru);
2082
2083static struct delta_base_cache_entry {
2084 struct list_head lru;
2085 void *data;
2086 struct packed_git *p;
2087 off_t base_offset;
2088 unsigned long size;
2089 enum object_type type;
2090} delta_base_cache[MAX_DELTA_CACHE];
2091
2092static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
2093{
2094 unsigned long hash;
2095
2096 hash = (unsigned long)(intptr_t)p + (unsigned long)base_offset;
2097 hash += (hash >> 8) + (hash >> 16);
2098 return hash % MAX_DELTA_CACHE;
2099}
2100
2101static struct delta_base_cache_entry *
2102get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
2103{
2104 unsigned long hash = pack_entry_hash(p, base_offset);
2105 return delta_base_cache + hash;
2106}
2107
2108static int eq_delta_base_cache_entry(struct delta_base_cache_entry *ent,
2109 struct packed_git *p, off_t base_offset)
2110{
2111 return (ent->data && ent->p == p && ent->base_offset == base_offset);
2112}
2113
2114static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
2115{
2116 struct delta_base_cache_entry *ent;
2117 ent = get_delta_base_cache_entry(p, base_offset);
2118 return eq_delta_base_cache_entry(ent, p, base_offset);
2119}
2120
2121/*
2122 * Remove the entry from the cache, but do _not_ free the associated
2123 * entry data. The caller takes ownership of the "data" buffer, and
2124 * should copy out any fields it wants before detaching.
2125 */
2126static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
2127{
2128 ent->data = NULL;
2129 list_del(&ent->lru);
2130 delta_base_cached -= ent->size;
2131}
2132
2133static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
2134 unsigned long *base_size, enum object_type *type)
2135{
2136 struct delta_base_cache_entry *ent;
2137
2138 ent = get_delta_base_cache_entry(p, base_offset);
2139
2140 if (!eq_delta_base_cache_entry(ent, p, base_offset))
2141 return unpack_entry(p, base_offset, type, base_size);
2142
2143 *type = ent->type;
2144 *base_size = ent->size;
2145 return xmemdupz(ent->data, ent->size);
2146}
2147
2148static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
2149{
2150 if (ent->data) {
2151 free(ent->data);
2152 detach_delta_base_cache_entry(ent);
2153 }
2154}
2155
2156void clear_delta_base_cache(void)
2157{
2158 unsigned long p;
2159 for (p = 0; p < MAX_DELTA_CACHE; p++)
2160 release_delta_base_cache(&delta_base_cache[p]);
2161}
2162
2163static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
2164 void *base, unsigned long base_size, enum object_type type)
2165{
2166 unsigned long hash = pack_entry_hash(p, base_offset);
2167 struct delta_base_cache_entry *ent = delta_base_cache + hash;
2168 struct list_head *lru;
2169
2170 release_delta_base_cache(ent);
2171 delta_base_cached += base_size;
2172
2173 list_for_each(lru, &delta_base_cache_lru) {
2174 struct delta_base_cache_entry *f =
2175 list_entry(lru, struct delta_base_cache_entry, lru);
2176 if (delta_base_cached <= delta_base_cache_limit)
2177 break;
2178 if (f->type == OBJ_BLOB)
2179 release_delta_base_cache(f);
2180 }
2181 list_for_each(lru, &delta_base_cache_lru) {
2182 struct delta_base_cache_entry *f =
2183 list_entry(lru, struct delta_base_cache_entry, lru);
2184 if (delta_base_cached <= delta_base_cache_limit)
2185 break;
2186 release_delta_base_cache(f);
2187 }
2188
2189 ent->p = p;
2190 ent->base_offset = base_offset;
2191 ent->type = type;
2192 ent->data = base;
2193 ent->size = base_size;
2194 list_add_tail(&ent->lru, &delta_base_cache_lru);
2195}
2196
2197static void *read_object(const unsigned char *sha1, enum object_type *type,
2198 unsigned long *size);
2199
2200static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
2201{
2202 static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
2203 trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
2204 p->pack_name, (uintmax_t)obj_offset);
2205}
2206
2207int do_check_packed_object_crc;
2208
2209#define UNPACK_ENTRY_STACK_PREALLOC 64
2210struct unpack_entry_stack_ent {
2211 off_t obj_offset;
2212 off_t curpos;
2213 unsigned long size;
2214};
2215
2216void *unpack_entry(struct packed_git *p, off_t obj_offset,
2217 enum object_type *final_type, unsigned long *final_size)
2218{
2219 struct pack_window *w_curs = NULL;
2220 off_t curpos = obj_offset;
2221 void *data = NULL;
2222 unsigned long size;
2223 enum object_type type;
2224 struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
2225 struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
2226 int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
2227 int base_from_cache = 0;
2228
2229 write_pack_access_log(p, obj_offset);
2230
2231 /* PHASE 1: drill down to the innermost base object */
2232 for (;;) {
2233 off_t base_offset;
2234 int i;
2235 struct delta_base_cache_entry *ent;
2236
2237 ent = get_delta_base_cache_entry(p, curpos);
2238 if (eq_delta_base_cache_entry(ent, p, curpos)) {
2239 type = ent->type;
2240 data = ent->data;
2241 size = ent->size;
2242 detach_delta_base_cache_entry(ent);
2243 base_from_cache = 1;
2244 break;
2245 }
2246
2247 if (do_check_packed_object_crc && p->index_version > 1) {
2248 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2249 off_t len = revidx[1].offset - obj_offset;
2250 if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
2251 const unsigned char *sha1 =
2252 nth_packed_object_sha1(p, revidx->nr);
2253 error("bad packed object CRC for %s",
2254 sha1_to_hex(sha1));
2255 mark_bad_packed_object(p, sha1);
2256 unuse_pack(&w_curs);
2257 return NULL;
2258 }
2259 }
2260
2261 type = unpack_object_header(p, &w_curs, &curpos, &size);
2262 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
2263 break;
2264
2265 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
2266 if (!base_offset) {
2267 error("failed to validate delta base reference "
2268 "at offset %"PRIuMAX" from %s",
2269 (uintmax_t)curpos, p->pack_name);
2270 /* bail to phase 2, in hopes of recovery */
2271 data = NULL;
2272 break;
2273 }
2274
2275 /* push object, proceed to base */
2276 if (delta_stack_nr >= delta_stack_alloc
2277 && delta_stack == small_delta_stack) {
2278 delta_stack_alloc = alloc_nr(delta_stack_nr);
2279 ALLOC_ARRAY(delta_stack, delta_stack_alloc);
2280 memcpy(delta_stack, small_delta_stack,
2281 sizeof(*delta_stack)*delta_stack_nr);
2282 } else {
2283 ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
2284 }
2285 i = delta_stack_nr++;
2286 delta_stack[i].obj_offset = obj_offset;
2287 delta_stack[i].curpos = curpos;
2288 delta_stack[i].size = size;
2289
2290 curpos = obj_offset = base_offset;
2291 }
2292
2293 /* PHASE 2: handle the base */
2294 switch (type) {
2295 case OBJ_OFS_DELTA:
2296 case OBJ_REF_DELTA:
2297 if (data)
2298 die("BUG: unpack_entry: left loop at a valid delta");
2299 break;
2300 case OBJ_COMMIT:
2301 case OBJ_TREE:
2302 case OBJ_BLOB:
2303 case OBJ_TAG:
2304 if (!base_from_cache)
2305 data = unpack_compressed_entry(p, &w_curs, curpos, size);
2306 break;
2307 default:
2308 data = NULL;
2309 error("unknown object type %i at offset %"PRIuMAX" in %s",
2310 type, (uintmax_t)obj_offset, p->pack_name);
2311 }
2312
2313 /* PHASE 3: apply deltas in order */
2314
2315 /* invariants:
2316 * 'data' holds the base data, or NULL if there was corruption
2317 */
2318 while (delta_stack_nr) {
2319 void *delta_data;
2320 void *base = data;
2321 unsigned long delta_size, base_size = size;
2322 int i;
2323
2324 data = NULL;
2325
2326 if (base)
2327 add_delta_base_cache(p, obj_offset, base, base_size, type);
2328
2329 if (!base) {
2330 /*
2331 * We're probably in deep shit, but let's try to fetch
2332 * the required base anyway from another pack or loose.
2333 * This is costly but should happen only in the presence
2334 * of a corrupted pack, and is better than failing outright.
2335 */
2336 struct revindex_entry *revidx;
2337 const unsigned char *base_sha1;
2338 revidx = find_pack_revindex(p, obj_offset);
2339 if (revidx) {
2340 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
2341 error("failed to read delta base object %s"
2342 " at offset %"PRIuMAX" from %s",
2343 sha1_to_hex(base_sha1), (uintmax_t)obj_offset,
2344 p->pack_name);
2345 mark_bad_packed_object(p, base_sha1);
2346 base = read_object(base_sha1, &type, &base_size);
2347 }
2348 }
2349
2350 i = --delta_stack_nr;
2351 obj_offset = delta_stack[i].obj_offset;
2352 curpos = delta_stack[i].curpos;
2353 delta_size = delta_stack[i].size;
2354
2355 if (!base)
2356 continue;
2357
2358 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
2359
2360 if (!delta_data) {
2361 error("failed to unpack compressed delta "
2362 "at offset %"PRIuMAX" from %s",
2363 (uintmax_t)curpos, p->pack_name);
2364 data = NULL;
2365 continue;
2366 }
2367
2368 data = patch_delta(base, base_size,
2369 delta_data, delta_size,
2370 &size);
2371
2372 /*
2373 * We could not apply the delta; warn the user, but keep going.
2374 * Our failure will be noticed either in the next iteration of
2375 * the loop, or if this is the final delta, in the caller when
2376 * we return NULL. Those code paths will take care of making
2377 * a more explicit warning and retrying with another copy of
2378 * the object.
2379 */
2380 if (!data)
2381 error("failed to apply delta");
2382
2383 free(delta_data);
2384 }
2385
2386 *final_type = type;
2387 *final_size = size;
2388
2389 unuse_pack(&w_curs);
2390
2391 if (delta_stack != small_delta_stack)
2392 free(delta_stack);
2393
2394 return data;
2395}
2396
2397const unsigned char *nth_packed_object_sha1(struct packed_git *p,
2398 uint32_t n)
2399{
2400 const unsigned char *index = p->index_data;
2401 if (!index) {
2402 if (open_pack_index(p))
2403 return NULL;
2404 index = p->index_data;
2405 }
2406 if (n >= p->num_objects)
2407 return NULL;
2408 index += 4 * 256;
2409 if (p->index_version == 1) {
2410 return index + 24 * n + 4;
2411 } else {
2412 index += 8;
2413 return index + 20 * n;
2414 }
2415}
2416
2417void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
2418{
2419 const unsigned char *ptr = vptr;
2420 const unsigned char *start = p->index_data;
2421 const unsigned char *end = start + p->index_size;
2422 if (ptr < start)
2423 die(_("offset before start of pack index for %s (corrupt index?)"),
2424 p->pack_name);
2425 /* No need to check for underflow; .idx files must be at least 8 bytes */
2426 if (ptr >= end - 8)
2427 die(_("offset beyond end of pack index for %s (truncated index?)"),
2428 p->pack_name);
2429}
2430
2431off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
2432{
2433 const unsigned char *index = p->index_data;
2434 index += 4 * 256;
2435 if (p->index_version == 1) {
2436 return ntohl(*((uint32_t *)(index + 24 * n)));
2437 } else {
2438 uint32_t off;
2439 index += 8 + p->num_objects * (20 + 4);
2440 off = ntohl(*((uint32_t *)(index + 4 * n)));
2441 if (!(off & 0x80000000))
2442 return off;
2443 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
2444 check_pack_index_ptr(p, index);
2445 return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
2446 ntohl(*((uint32_t *)(index + 4)));
2447 }
2448}
2449
2450off_t find_pack_entry_one(const unsigned char *sha1,
2451 struct packed_git *p)
2452{
2453 const uint32_t *level1_ofs = p->index_data;
2454 const unsigned char *index = p->index_data;
2455 unsigned hi, lo, stride;
2456 static int use_lookup = -1;
2457 static int debug_lookup = -1;
2458
2459 if (debug_lookup < 0)
2460 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
2461
2462 if (!index) {
2463 if (open_pack_index(p))
2464 return 0;
2465 level1_ofs = p->index_data;
2466 index = p->index_data;
2467 }
2468 if (p->index_version > 1) {
2469 level1_ofs += 2;
2470 index += 8;
2471 }
2472 index += 4 * 256;
2473 hi = ntohl(level1_ofs[*sha1]);
2474 lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
2475 if (p->index_version > 1) {
2476 stride = 20;
2477 } else {
2478 stride = 24;
2479 index += 4;
2480 }
2481
2482 if (debug_lookup)
2483 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
2484 sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
2485
2486 if (use_lookup < 0)
2487 use_lookup = !!getenv("GIT_USE_LOOKUP");
2488 if (use_lookup) {
2489 int pos = sha1_entry_pos(index, stride, 0,
2490 lo, hi, p->num_objects, sha1);
2491 if (pos < 0)
2492 return 0;
2493 return nth_packed_object_offset(p, pos);
2494 }
2495
2496 do {
2497 unsigned mi = (lo + hi) / 2;
2498 int cmp = hashcmp(index + mi * stride, sha1);
2499
2500 if (debug_lookup)
2501 printf("lo %u hi %u rg %u mi %u\n",
2502 lo, hi, hi - lo, mi);
2503 if (!cmp)
2504 return nth_packed_object_offset(p, mi);
2505 if (cmp > 0)
2506 hi = mi;
2507 else
2508 lo = mi+1;
2509 } while (lo < hi);
2510 return 0;
2511}
2512
2513int is_pack_valid(struct packed_git *p)
2514{
2515 /* An already open pack is known to be valid. */
2516 if (p->pack_fd != -1)
2517 return 1;
2518
2519 /* If the pack has one window completely covering the
2520 * file size, the pack is known to be valid even if
2521 * the descriptor is not currently open.
2522 */
2523 if (p->windows) {
2524 struct pack_window *w = p->windows;
2525
2526 if (!w->offset && w->len == p->pack_size)
2527 return 1;
2528 }
2529
2530 /* Force the pack to open to prove its valid. */
2531 return !open_packed_git(p);
2532}
2533
2534static int fill_pack_entry(const unsigned char *sha1,
2535 struct pack_entry *e,
2536 struct packed_git *p)
2537{
2538 off_t offset;
2539
2540 if (p->num_bad_objects) {
2541 unsigned i;
2542 for (i = 0; i < p->num_bad_objects; i++)
2543 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
2544 return 0;
2545 }
2546
2547 offset = find_pack_entry_one(sha1, p);
2548 if (!offset)
2549 return 0;
2550
2551 /*
2552 * We are about to tell the caller where they can locate the
2553 * requested object. We better make sure the packfile is
2554 * still here and can be accessed before supplying that
2555 * answer, as it may have been deleted since the index was
2556 * loaded!
2557 */
2558 if (!is_pack_valid(p))
2559 return 0;
2560 e->offset = offset;
2561 e->p = p;
2562 hashcpy(e->sha1, sha1);
2563 return 1;
2564}
2565
2566/*
2567 * Iff a pack file contains the object named by sha1, return true and
2568 * store its location to e.
2569 */
2570static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
2571{
2572 struct mru_entry *p;
2573
2574 prepare_packed_git();
2575 if (!packed_git)
2576 return 0;
2577
2578 for (p = packed_git_mru->head; p; p = p->next) {
2579 if (fill_pack_entry(sha1, e, p->item)) {
2580 mru_mark(packed_git_mru, p);
2581 return 1;
2582 }
2583 }
2584 return 0;
2585}
2586
2587struct packed_git *find_sha1_pack(const unsigned char *sha1,
2588 struct packed_git *packs)
2589{
2590 struct packed_git *p;
2591
2592 for (p = packs; p; p = p->next) {
2593 if (find_pack_entry_one(sha1, p))
2594 return p;
2595 }
2596 return NULL;
2597
2598}
2599
2600static int sha1_loose_object_info(const unsigned char *sha1,
2601 struct object_info *oi,
2602 int flags)
2603{
2604 int status = 0;
2605 unsigned long mapsize;
2606 void *map;
2607 git_zstream stream;
2608 char hdr[32];
2609 struct strbuf hdrbuf = STRBUF_INIT;
2610
2611 if (oi->delta_base_sha1)
2612 hashclr(oi->delta_base_sha1);
2613
2614 /*
2615 * If we don't care about type or size, then we don't
2616 * need to look inside the object at all. Note that we
2617 * do not optimize out the stat call, even if the
2618 * caller doesn't care about the disk-size, since our
2619 * return value implicitly indicates whether the
2620 * object even exists.
2621 */
2622 if (!oi->typep && !oi->typename && !oi->sizep) {
2623 struct stat st;
2624 if (stat_sha1_file(sha1, &st) < 0)
2625 return -1;
2626 if (oi->disk_sizep)
2627 *oi->disk_sizep = st.st_size;
2628 return 0;
2629 }
2630
2631 map = map_sha1_file(sha1, &mapsize);
2632 if (!map)
2633 return -1;
2634 if (oi->disk_sizep)
2635 *oi->disk_sizep = mapsize;
2636 if ((flags & LOOKUP_UNKNOWN_OBJECT)) {
2637 if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
2638 status = error("unable to unpack %s header with --allow-unknown-type",
2639 sha1_to_hex(sha1));
2640 } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2641 status = error("unable to unpack %s header",
2642 sha1_to_hex(sha1));
2643 if (status < 0)
2644 ; /* Do nothing */
2645 else if (hdrbuf.len) {
2646 if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
2647 status = error("unable to parse %s header with --allow-unknown-type",
2648 sha1_to_hex(sha1));
2649 } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
2650 status = error("unable to parse %s header", sha1_to_hex(sha1));
2651 git_inflate_end(&stream);
2652 munmap(map, mapsize);
2653 if (status && oi->typep)
2654 *oi->typep = status;
2655 strbuf_release(&hdrbuf);
2656 return 0;
2657}
2658
2659int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
2660{
2661 struct cached_object *co;
2662 struct pack_entry e;
2663 int rtype;
2664 enum object_type real_type;
2665 const unsigned char *real = lookup_replace_object_extended(sha1, flags);
2666
2667 co = find_cached_object(real);
2668 if (co) {
2669 if (oi->typep)
2670 *(oi->typep) = co->type;
2671 if (oi->sizep)
2672 *(oi->sizep) = co->size;
2673 if (oi->disk_sizep)
2674 *(oi->disk_sizep) = 0;
2675 if (oi->delta_base_sha1)
2676 hashclr(oi->delta_base_sha1);
2677 if (oi->typename)
2678 strbuf_addstr(oi->typename, typename(co->type));
2679 oi->whence = OI_CACHED;
2680 return 0;
2681 }
2682
2683 if (!find_pack_entry(real, &e)) {
2684 /* Most likely it's a loose object. */
2685 if (!sha1_loose_object_info(real, oi, flags)) {
2686 oi->whence = OI_LOOSE;
2687 return 0;
2688 }
2689
2690 /* Not a loose object; someone else may have just packed it. */
2691 reprepare_packed_git();
2692 if (!find_pack_entry(real, &e))
2693 return -1;
2694 }
2695
2696 /*
2697 * packed_object_info() does not follow the delta chain to
2698 * find out the real type, unless it is given oi->typep.
2699 */
2700 if (oi->typename && !oi->typep)
2701 oi->typep = &real_type;
2702
2703 rtype = packed_object_info(e.p, e.offset, oi);
2704 if (rtype < 0) {
2705 mark_bad_packed_object(e.p, real);
2706 if (oi->typep == &real_type)
2707 oi->typep = NULL;
2708 return sha1_object_info_extended(real, oi, 0);
2709 } else if (in_delta_base_cache(e.p, e.offset)) {
2710 oi->whence = OI_DBCACHED;
2711 } else {
2712 oi->whence = OI_PACKED;
2713 oi->u.packed.offset = e.offset;
2714 oi->u.packed.pack = e.p;
2715 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
2716 rtype == OBJ_OFS_DELTA);
2717 }
2718 if (oi->typename)
2719 strbuf_addstr(oi->typename, typename(*oi->typep));
2720 if (oi->typep == &real_type)
2721 oi->typep = NULL;
2722
2723 return 0;
2724}
2725
2726/* returns enum object_type or negative */
2727int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2728{
2729 enum object_type type;
2730 struct object_info oi = {NULL};
2731
2732 oi.typep = &type;
2733 oi.sizep = sizep;
2734 if (sha1_object_info_extended(sha1, &oi, LOOKUP_REPLACE_OBJECT) < 0)
2735 return -1;
2736 return type;
2737}
2738
2739static void *read_packed_sha1(const unsigned char *sha1,
2740 enum object_type *type, unsigned long *size)
2741{
2742 struct pack_entry e;
2743 void *data;
2744
2745 if (!find_pack_entry(sha1, &e))
2746 return NULL;
2747 data = cache_or_unpack_entry(e.p, e.offset, size, type);
2748 if (!data) {
2749 /*
2750 * We're probably in deep shit, but let's try to fetch
2751 * the required object anyway from another pack or loose.
2752 * This should happen only in the presence of a corrupted
2753 * pack, and is better than failing outright.
2754 */
2755 error("failed to read object %s at offset %"PRIuMAX" from %s",
2756 sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2757 mark_bad_packed_object(e.p, sha1);
2758 data = read_object(sha1, type, size);
2759 }
2760 return data;
2761}
2762
2763int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2764 unsigned char *sha1)
2765{
2766 struct cached_object *co;
2767
2768 hash_sha1_file(buf, len, typename(type), sha1);
2769 if (has_sha1_file(sha1) || find_cached_object(sha1))
2770 return 0;
2771 ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
2772 co = &cached_objects[cached_object_nr++];
2773 co->size = len;
2774 co->type = type;
2775 co->buf = xmalloc(len);
2776 memcpy(co->buf, buf, len);
2777 hashcpy(co->sha1, sha1);
2778 return 0;
2779}
2780
2781static void *read_object(const unsigned char *sha1, enum object_type *type,
2782 unsigned long *size)
2783{
2784 unsigned long mapsize;
2785 void *map, *buf;
2786 struct cached_object *co;
2787
2788 co = find_cached_object(sha1);
2789 if (co) {
2790 *type = co->type;
2791 *size = co->size;
2792 return xmemdupz(co->buf, co->size);
2793 }
2794
2795 buf = read_packed_sha1(sha1, type, size);
2796 if (buf)
2797 return buf;
2798 map = map_sha1_file(sha1, &mapsize);
2799 if (map) {
2800 buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2801 munmap(map, mapsize);
2802 return buf;
2803 }
2804 reprepare_packed_git();
2805 return read_packed_sha1(sha1, type, size);
2806}
2807
2808/*
2809 * This function dies on corrupt objects; the callers who want to
2810 * deal with them should arrange to call read_object() and give error
2811 * messages themselves.
2812 */
2813void *read_sha1_file_extended(const unsigned char *sha1,
2814 enum object_type *type,
2815 unsigned long *size,
2816 unsigned flag)
2817{
2818 void *data;
2819 const struct packed_git *p;
2820 const unsigned char *repl = lookup_replace_object_extended(sha1, flag);
2821
2822 errno = 0;
2823 data = read_object(repl, type, size);
2824 if (data)
2825 return data;
2826
2827 if (errno && errno != ENOENT)
2828 die_errno("failed to read object %s", sha1_to_hex(sha1));
2829
2830 /* die if we replaced an object with one that does not exist */
2831 if (repl != sha1)
2832 die("replacement %s not found for %s",
2833 sha1_to_hex(repl), sha1_to_hex(sha1));
2834
2835 if (has_loose_object(repl)) {
2836 const char *path = sha1_file_name(sha1);
2837
2838 die("loose object %s (stored in %s) is corrupt",
2839 sha1_to_hex(repl), path);
2840 }
2841
2842 if ((p = has_packed_and_bad(repl)) != NULL)
2843 die("packed object %s (stored in %s) is corrupt",
2844 sha1_to_hex(repl), p->pack_name);
2845
2846 return NULL;
2847}
2848
2849void *read_object_with_reference(const unsigned char *sha1,
2850 const char *required_type_name,
2851 unsigned long *size,
2852 unsigned char *actual_sha1_return)
2853{
2854 enum object_type type, required_type;
2855 void *buffer;
2856 unsigned long isize;
2857 unsigned char actual_sha1[20];
2858
2859 required_type = type_from_string(required_type_name);
2860 hashcpy(actual_sha1, sha1);
2861 while (1) {
2862 int ref_length = -1;
2863 const char *ref_type = NULL;
2864
2865 buffer = read_sha1_file(actual_sha1, &type, &isize);
2866 if (!buffer)
2867 return NULL;
2868 if (type == required_type) {
2869 *size = isize;
2870 if (actual_sha1_return)
2871 hashcpy(actual_sha1_return, actual_sha1);
2872 return buffer;
2873 }
2874 /* Handle references */
2875 else if (type == OBJ_COMMIT)
2876 ref_type = "tree ";
2877 else if (type == OBJ_TAG)
2878 ref_type = "object ";
2879 else {
2880 free(buffer);
2881 return NULL;
2882 }
2883 ref_length = strlen(ref_type);
2884
2885 if (ref_length + 40 > isize ||
2886 memcmp(buffer, ref_type, ref_length) ||
2887 get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2888 free(buffer);
2889 return NULL;
2890 }
2891 free(buffer);
2892 /* Now we have the ID of the referred-to object in
2893 * actual_sha1. Check again. */
2894 }
2895}
2896
2897static void write_sha1_file_prepare(const void *buf, unsigned long len,
2898 const char *type, unsigned char *sha1,
2899 char *hdr, int *hdrlen)
2900{
2901 git_SHA_CTX c;
2902
2903 /* Generate the header */
2904 *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
2905
2906 /* Sha1.. */
2907 git_SHA1_Init(&c);
2908 git_SHA1_Update(&c, hdr, *hdrlen);
2909 git_SHA1_Update(&c, buf, len);
2910 git_SHA1_Final(sha1, &c);
2911}
2912
2913/*
2914 * Move the just written object into its final resting place.
2915 */
2916int finalize_object_file(const char *tmpfile, const char *filename)
2917{
2918 int ret = 0;
2919
2920 if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2921 goto try_rename;
2922 else if (link(tmpfile, filename))
2923 ret = errno;
2924
2925 /*
2926 * Coda hack - coda doesn't like cross-directory links,
2927 * so we fall back to a rename, which will mean that it
2928 * won't be able to check collisions, but that's not a
2929 * big deal.
2930 *
2931 * The same holds for FAT formatted media.
2932 *
2933 * When this succeeds, we just return. We have nothing
2934 * left to unlink.
2935 */
2936 if (ret && ret != EEXIST) {
2937 try_rename:
2938 if (!rename(tmpfile, filename))
2939 goto out;
2940 ret = errno;
2941 }
2942 unlink_or_warn(tmpfile);
2943 if (ret) {
2944 if (ret != EEXIST) {
2945 return error_errno("unable to write sha1 filename %s", filename);
2946 }
2947 /* FIXME!!! Collision check here ? */
2948 }
2949
2950out:
2951 if (adjust_shared_perm(filename))
2952 return error("unable to set permission to '%s'", filename);
2953 return 0;
2954}
2955
2956static int write_buffer(int fd, const void *buf, size_t len)
2957{
2958 if (write_in_full(fd, buf, len) < 0)
2959 return error_errno("file write error");
2960 return 0;
2961}
2962
2963int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2964 unsigned char *sha1)
2965{
2966 char hdr[32];
2967 int hdrlen = sizeof(hdr);
2968 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2969 return 0;
2970}
2971
2972/* Finalize a file on disk, and close it. */
2973static void close_sha1_file(int fd)
2974{
2975 if (fsync_object_files)
2976 fsync_or_die(fd, "sha1 file");
2977 if (close(fd) != 0)
2978 die_errno("error when closing sha1 file");
2979}
2980
2981/* Size of directory component, including the ending '/' */
2982static inline int directory_size(const char *filename)
2983{
2984 const char *s = strrchr(filename, '/');
2985 if (!s)
2986 return 0;
2987 return s - filename + 1;
2988}
2989
2990/*
2991 * This creates a temporary file in the same directory as the final
2992 * 'filename'
2993 *
2994 * We want to avoid cross-directory filename renames, because those
2995 * can have problems on various filesystems (FAT, NFS, Coda).
2996 */
2997static int create_tmpfile(struct strbuf *tmp, const char *filename)
2998{
2999 int fd, dirlen = directory_size(filename);
3000
3001 strbuf_reset(tmp);
3002 strbuf_add(tmp, filename, dirlen);
3003 strbuf_addstr(tmp, "tmp_obj_XXXXXX");
3004 fd = git_mkstemp_mode(tmp->buf, 0444);
3005 if (fd < 0 && dirlen && errno == ENOENT) {
3006 /*
3007 * Make sure the directory exists; note that the contents
3008 * of the buffer are undefined after mkstemp returns an
3009 * error, so we have to rewrite the whole buffer from
3010 * scratch.
3011 */
3012 strbuf_reset(tmp);
3013 strbuf_add(tmp, filename, dirlen - 1);
3014 if (mkdir(tmp->buf, 0777) && errno != EEXIST)
3015 return -1;
3016 if (adjust_shared_perm(tmp->buf))
3017 return -1;
3018
3019 /* Try again */
3020 strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
3021 fd = git_mkstemp_mode(tmp->buf, 0444);
3022 }
3023 return fd;
3024}
3025
3026static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
3027 const void *buf, unsigned long len, time_t mtime)
3028{
3029 int fd, ret;
3030 unsigned char compressed[4096];
3031 git_zstream stream;
3032 git_SHA_CTX c;
3033 unsigned char parano_sha1[20];
3034 static struct strbuf tmp_file = STRBUF_INIT;
3035 const char *filename = sha1_file_name(sha1);
3036
3037 fd = create_tmpfile(&tmp_file, filename);
3038 if (fd < 0) {
3039 if (errno == EACCES)
3040 return error("insufficient permission for adding an object to repository database %s", get_object_directory());
3041 else
3042 return error_errno("unable to create temporary file");
3043 }
3044
3045 /* Set it up */
3046 git_deflate_init(&stream, zlib_compression_level);
3047 stream.next_out = compressed;
3048 stream.avail_out = sizeof(compressed);
3049 git_SHA1_Init(&c);
3050
3051 /* First header.. */
3052 stream.next_in = (unsigned char *)hdr;
3053 stream.avail_in = hdrlen;
3054 while (git_deflate(&stream, 0) == Z_OK)
3055 ; /* nothing */
3056 git_SHA1_Update(&c, hdr, hdrlen);
3057
3058 /* Then the data itself.. */
3059 stream.next_in = (void *)buf;
3060 stream.avail_in = len;
3061 do {
3062 unsigned char *in0 = stream.next_in;
3063 ret = git_deflate(&stream, Z_FINISH);
3064 git_SHA1_Update(&c, in0, stream.next_in - in0);
3065 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
3066 die("unable to write sha1 file");
3067 stream.next_out = compressed;
3068 stream.avail_out = sizeof(compressed);
3069 } while (ret == Z_OK);
3070
3071 if (ret != Z_STREAM_END)
3072 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
3073 ret = git_deflate_end_gently(&stream);
3074 if (ret != Z_OK)
3075 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
3076 git_SHA1_Final(parano_sha1, &c);
3077 if (hashcmp(sha1, parano_sha1) != 0)
3078 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
3079
3080 close_sha1_file(fd);
3081
3082 if (mtime) {
3083 struct utimbuf utb;
3084 utb.actime = mtime;
3085 utb.modtime = mtime;
3086 if (utime(tmp_file.buf, &utb) < 0)
3087 warning_errno("failed utime() on %s", tmp_file.buf);
3088 }
3089
3090 return finalize_object_file(tmp_file.buf, filename);
3091}
3092
3093static int freshen_loose_object(const unsigned char *sha1)
3094{
3095 return check_and_freshen(sha1, 1);
3096}
3097
3098static int freshen_packed_object(const unsigned char *sha1)
3099{
3100 struct pack_entry e;
3101 if (!find_pack_entry(sha1, &e))
3102 return 0;
3103 if (e.p->freshened)
3104 return 1;
3105 if (!freshen_file(e.p->pack_name))
3106 return 0;
3107 e.p->freshened = 1;
3108 return 1;
3109}
3110
3111int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
3112{
3113 char hdr[32];
3114 int hdrlen = sizeof(hdr);
3115
3116 /* Normally if we have it in the pack then we do not bother writing
3117 * it out into .git/objects/??/?{38} file.
3118 */
3119 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
3120 if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3121 return 0;
3122 return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
3123}
3124
3125int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
3126 unsigned char *sha1, unsigned flags)
3127{
3128 char *header;
3129 int hdrlen, status = 0;
3130
3131 /* type string, SP, %lu of the length plus NUL must fit this */
3132 hdrlen = strlen(type) + 32;
3133 header = xmalloc(hdrlen);
3134 write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
3135
3136 if (!(flags & HASH_WRITE_OBJECT))
3137 goto cleanup;
3138 if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3139 goto cleanup;
3140 status = write_loose_object(sha1, header, hdrlen, buf, len, 0);
3141
3142cleanup:
3143 free(header);
3144 return status;
3145}
3146
3147int force_object_loose(const unsigned char *sha1, time_t mtime)
3148{
3149 void *buf;
3150 unsigned long len;
3151 enum object_type type;
3152 char hdr[32];
3153 int hdrlen;
3154 int ret;
3155
3156 if (has_loose_object(sha1))
3157 return 0;
3158 buf = read_packed_sha1(sha1, &type, &len);
3159 if (!buf)
3160 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
3161 hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
3162 ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
3163 free(buf);
3164
3165 return ret;
3166}
3167
3168int has_pack_index(const unsigned char *sha1)
3169{
3170 struct stat st;
3171 if (stat(sha1_pack_index_name(sha1), &st))
3172 return 0;
3173 return 1;
3174}
3175
3176int has_sha1_pack(const unsigned char *sha1)
3177{
3178 struct pack_entry e;
3179 return find_pack_entry(sha1, &e);
3180}
3181
3182int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
3183{
3184 struct pack_entry e;
3185
3186 if (find_pack_entry(sha1, &e))
3187 return 1;
3188 if (has_loose_object(sha1))
3189 return 1;
3190 if (flags & HAS_SHA1_QUICK)
3191 return 0;
3192 reprepare_packed_git();
3193 return find_pack_entry(sha1, &e);
3194}
3195
3196int has_object_file(const struct object_id *oid)
3197{
3198 return has_sha1_file(oid->hash);
3199}
3200
3201static void check_tree(const void *buf, size_t size)
3202{
3203 struct tree_desc desc;
3204 struct name_entry entry;
3205
3206 init_tree_desc(&desc, buf, size);
3207 while (tree_entry(&desc, &entry))
3208 /* do nothing
3209 * tree_entry() will die() on malformed entries */
3210 ;
3211}
3212
3213static void check_commit(const void *buf, size_t size)
3214{
3215 struct commit c;
3216 memset(&c, 0, sizeof(c));
3217 if (parse_commit_buffer(&c, buf, size))
3218 die("corrupt commit");
3219}
3220
3221static void check_tag(const void *buf, size_t size)
3222{
3223 struct tag t;
3224 memset(&t, 0, sizeof(t));
3225 if (parse_tag_buffer(&t, buf, size))
3226 die("corrupt tag");
3227}
3228
3229static int index_mem(unsigned char *sha1, void *buf, size_t size,
3230 enum object_type type,
3231 const char *path, unsigned flags)
3232{
3233 int ret, re_allocated = 0;
3234 int write_object = flags & HASH_WRITE_OBJECT;
3235
3236 if (!type)
3237 type = OBJ_BLOB;
3238
3239 /*
3240 * Convert blobs to git internal format
3241 */
3242 if ((type == OBJ_BLOB) && path) {
3243 struct strbuf nbuf = STRBUF_INIT;
3244 if (convert_to_git(path, buf, size, &nbuf,
3245 write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
3246 buf = strbuf_detach(&nbuf, &size);
3247 re_allocated = 1;
3248 }
3249 }
3250 if (flags & HASH_FORMAT_CHECK) {
3251 if (type == OBJ_TREE)
3252 check_tree(buf, size);
3253 if (type == OBJ_COMMIT)
3254 check_commit(buf, size);
3255 if (type == OBJ_TAG)
3256 check_tag(buf, size);
3257 }
3258
3259 if (write_object)
3260 ret = write_sha1_file(buf, size, typename(type), sha1);
3261 else
3262 ret = hash_sha1_file(buf, size, typename(type), sha1);
3263 if (re_allocated)
3264 free(buf);
3265 return ret;
3266}
3267
3268static int index_stream_convert_blob(unsigned char *sha1, int fd,
3269 const char *path, unsigned flags)
3270{
3271 int ret;
3272 const int write_object = flags & HASH_WRITE_OBJECT;
3273 struct strbuf sbuf = STRBUF_INIT;
3274
3275 assert(path);
3276 assert(would_convert_to_git_filter_fd(path));
3277
3278 convert_to_git_filter_fd(path, fd, &sbuf,
3279 write_object ? safe_crlf : SAFE_CRLF_FALSE);
3280
3281 if (write_object)
3282 ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3283 sha1);
3284 else
3285 ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3286 sha1);
3287 strbuf_release(&sbuf);
3288 return ret;
3289}
3290
3291static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
3292 const char *path, unsigned flags)
3293{
3294 struct strbuf sbuf = STRBUF_INIT;
3295 int ret;
3296
3297 if (strbuf_read(&sbuf, fd, 4096) >= 0)
3298 ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
3299 else
3300 ret = -1;
3301 strbuf_release(&sbuf);
3302 return ret;
3303}
3304
3305#define SMALL_FILE_SIZE (32*1024)
3306
3307static int index_core(unsigned char *sha1, int fd, size_t size,
3308 enum object_type type, const char *path,
3309 unsigned flags)
3310{
3311 int ret;
3312
3313 if (!size) {
3314 ret = index_mem(sha1, "", size, type, path, flags);
3315 } else if (size <= SMALL_FILE_SIZE) {
3316 char *buf = xmalloc(size);
3317 if (size == read_in_full(fd, buf, size))
3318 ret = index_mem(sha1, buf, size, type, path, flags);
3319 else
3320 ret = error_errno("short read");
3321 free(buf);
3322 } else {
3323 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
3324 ret = index_mem(sha1, buf, size, type, path, flags);
3325 munmap(buf, size);
3326 }
3327 return ret;
3328}
3329
3330/*
3331 * This creates one packfile per large blob unless bulk-checkin
3332 * machinery is "plugged".
3333 *
3334 * This also bypasses the usual "convert-to-git" dance, and that is on
3335 * purpose. We could write a streaming version of the converting
3336 * functions and insert that before feeding the data to fast-import
3337 * (or equivalent in-core API described above). However, that is
3338 * somewhat complicated, as we do not know the size of the filter
3339 * result, which we need to know beforehand when writing a git object.
3340 * Since the primary motivation for trying to stream from the working
3341 * tree file and to avoid mmaping it in core is to deal with large
3342 * binary blobs, they generally do not want to get any conversion, and
3343 * callers should avoid this code path when filters are requested.
3344 */
3345static int index_stream(unsigned char *sha1, int fd, size_t size,
3346 enum object_type type, const char *path,
3347 unsigned flags)
3348{
3349 return index_bulk_checkin(sha1, fd, size, type, path, flags);
3350}
3351
3352int index_fd(unsigned char *sha1, int fd, struct stat *st,
3353 enum object_type type, const char *path, unsigned flags)
3354{
3355 int ret;
3356
3357 /*
3358 * Call xsize_t() only when needed to avoid potentially unnecessary
3359 * die() for large files.
3360 */
3361 if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
3362 ret = index_stream_convert_blob(sha1, fd, path, flags);
3363 else if (!S_ISREG(st->st_mode))
3364 ret = index_pipe(sha1, fd, type, path, flags);
3365 else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
3366 (path && would_convert_to_git(path)))
3367 ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
3368 flags);
3369 else
3370 ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
3371 flags);
3372 close(fd);
3373 return ret;
3374}
3375
3376int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
3377{
3378 int fd;
3379 struct strbuf sb = STRBUF_INIT;
3380
3381 switch (st->st_mode & S_IFMT) {
3382 case S_IFREG:
3383 fd = open(path, O_RDONLY);
3384 if (fd < 0)
3385 return error_errno("open(\"%s\")", path);
3386 if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
3387 return error("%s: failed to insert into database",
3388 path);
3389 break;
3390 case S_IFLNK:
3391 if (strbuf_readlink(&sb, path, st->st_size))
3392 return error_errno("readlink(\"%s\")", path);
3393 if (!(flags & HASH_WRITE_OBJECT))
3394 hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
3395 else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
3396 return error("%s: failed to insert into database",
3397 path);
3398 strbuf_release(&sb);
3399 break;
3400 case S_IFDIR:
3401 return resolve_gitlink_ref(path, "HEAD", sha1);
3402 default:
3403 return error("%s: unsupported file type", path);
3404 }
3405 return 0;
3406}
3407
3408int read_pack_header(int fd, struct pack_header *header)
3409{
3410 if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
3411 /* "eof before pack header was fully read" */
3412 return PH_ERROR_EOF;
3413
3414 if (header->hdr_signature != htonl(PACK_SIGNATURE))
3415 /* "protocol error (pack signature mismatch detected)" */
3416 return PH_ERROR_PACK_SIGNATURE;
3417 if (!pack_version_ok(header->hdr_version))
3418 /* "protocol error (pack version unsupported)" */
3419 return PH_ERROR_PROTOCOL;
3420 return 0;
3421}
3422
3423void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
3424{
3425 enum object_type type = sha1_object_info(sha1, NULL);
3426 if (type < 0)
3427 die("%s is not a valid object", sha1_to_hex(sha1));
3428 if (type != expect)
3429 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
3430 typename(expect));
3431}
3432
3433static int for_each_file_in_obj_subdir(int subdir_nr,
3434 struct strbuf *path,
3435 each_loose_object_fn obj_cb,
3436 each_loose_cruft_fn cruft_cb,
3437 each_loose_subdir_fn subdir_cb,
3438 void *data)
3439{
3440 size_t baselen = path->len;
3441 DIR *dir = opendir(path->buf);
3442 struct dirent *de;
3443 int r = 0;
3444
3445 if (!dir) {
3446 if (errno == ENOENT)
3447 return 0;
3448 return error_errno("unable to open %s", path->buf);
3449 }
3450
3451 while ((de = readdir(dir))) {
3452 if (is_dot_or_dotdot(de->d_name))
3453 continue;
3454
3455 strbuf_setlen(path, baselen);
3456 strbuf_addf(path, "/%s", de->d_name);
3457
3458 if (strlen(de->d_name) == 38) {
3459 char hex[41];
3460 unsigned char sha1[20];
3461
3462 snprintf(hex, sizeof(hex), "%02x%s",
3463 subdir_nr, de->d_name);
3464 if (!get_sha1_hex(hex, sha1)) {
3465 if (obj_cb) {
3466 r = obj_cb(sha1, path->buf, data);
3467 if (r)
3468 break;
3469 }
3470 continue;
3471 }
3472 }
3473
3474 if (cruft_cb) {
3475 r = cruft_cb(de->d_name, path->buf, data);
3476 if (r)
3477 break;
3478 }
3479 }
3480 closedir(dir);
3481
3482 strbuf_setlen(path, baselen);
3483 if (!r && subdir_cb)
3484 r = subdir_cb(subdir_nr, path->buf, data);
3485
3486 return r;
3487}
3488
3489int for_each_loose_file_in_objdir_buf(struct strbuf *path,
3490 each_loose_object_fn obj_cb,
3491 each_loose_cruft_fn cruft_cb,
3492 each_loose_subdir_fn subdir_cb,
3493 void *data)
3494{
3495 size_t baselen = path->len;
3496 int r = 0;
3497 int i;
3498
3499 for (i = 0; i < 256; i++) {
3500 strbuf_addf(path, "/%02x", i);
3501 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
3502 subdir_cb, data);
3503 strbuf_setlen(path, baselen);
3504 if (r)
3505 break;
3506 }
3507
3508 return r;
3509}
3510
3511int for_each_loose_file_in_objdir(const char *path,
3512 each_loose_object_fn obj_cb,
3513 each_loose_cruft_fn cruft_cb,
3514 each_loose_subdir_fn subdir_cb,
3515 void *data)
3516{
3517 struct strbuf buf = STRBUF_INIT;
3518 int r;
3519
3520 strbuf_addstr(&buf, path);
3521 r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
3522 subdir_cb, data);
3523 strbuf_release(&buf);
3524
3525 return r;
3526}
3527
3528struct loose_alt_odb_data {
3529 each_loose_object_fn *cb;
3530 void *data;
3531};
3532
3533static int loose_from_alt_odb(struct alternate_object_database *alt,
3534 void *vdata)
3535{
3536 struct loose_alt_odb_data *data = vdata;
3537 struct strbuf buf = STRBUF_INIT;
3538 int r;
3539
3540 /* copy base not including trailing '/' */
3541 strbuf_add(&buf, alt->base, alt->name - alt->base - 1);
3542 r = for_each_loose_file_in_objdir_buf(&buf,
3543 data->cb, NULL, NULL,
3544 data->data);
3545 strbuf_release(&buf);
3546 return r;
3547}
3548
3549int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
3550{
3551 struct loose_alt_odb_data alt;
3552 int r;
3553
3554 r = for_each_loose_file_in_objdir(get_object_directory(),
3555 cb, NULL, NULL, data);
3556 if (r)
3557 return r;
3558
3559 if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
3560 return 0;
3561
3562 alt.cb = cb;
3563 alt.data = data;
3564 return foreach_alt_odb(loose_from_alt_odb, &alt);
3565}
3566
3567static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
3568{
3569 uint32_t i;
3570 int r = 0;
3571
3572 for (i = 0; i < p->num_objects; i++) {
3573 const unsigned char *sha1 = nth_packed_object_sha1(p, i);
3574
3575 if (!sha1)
3576 return error("unable to get sha1 of object %u in %s",
3577 i, p->pack_name);
3578
3579 r = cb(sha1, p, i, data);
3580 if (r)
3581 break;
3582 }
3583 return r;
3584}
3585
3586int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
3587{
3588 struct packed_git *p;
3589 int r = 0;
3590 int pack_errors = 0;
3591
3592 prepare_packed_git();
3593 for (p = packed_git; p; p = p->next) {
3594 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
3595 continue;
3596 if (open_pack_index(p)) {
3597 pack_errors = 1;
3598 continue;
3599 }
3600 r = for_each_object_in_pack(p, cb, data);
3601 if (r)
3602 break;
3603 }
3604 return r ? r : pack_errors;
3605}