5fa7d27d3b6659964a7c15e54a9a9e2047e909b3
[git/git.git] / packfile.c
1 #include "cache.h"
2 #include "list.h"
3 #include "pack.h"
4 #include "repository.h"
5 #include "dir.h"
6 #include "mergesort.h"
7 #include "packfile.h"
8 #include "delta.h"
9 #include "list.h"
10 #include "streaming.h"
11 #include "sha1-lookup.h"
12 #include "commit.h"
13 #include "object.h"
14 #include "tag.h"
15 #include "tree-walk.h"
16 #include "tree.h"
17 #include "object-store.h"
18
19 char *odb_pack_name(struct strbuf *buf,
20 const unsigned char *sha1,
21 const char *ext)
22 {
23 strbuf_reset(buf);
24 strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
25 sha1_to_hex(sha1), ext);
26 return buf->buf;
27 }
28
29 char *sha1_pack_name(const unsigned char *sha1)
30 {
31 static struct strbuf buf = STRBUF_INIT;
32 return odb_pack_name(&buf, sha1, "pack");
33 }
34
35 char *sha1_pack_index_name(const unsigned char *sha1)
36 {
37 static struct strbuf buf = STRBUF_INIT;
38 return odb_pack_name(&buf, sha1, "idx");
39 }
40
41 static unsigned int pack_used_ctr;
42 static unsigned int pack_mmap_calls;
43 static unsigned int peak_pack_open_windows;
44 static unsigned int pack_open_windows;
45 static unsigned int pack_open_fds;
46 static unsigned int pack_max_fds;
47 static size_t peak_pack_mapped;
48 static size_t pack_mapped;
49
50 #define SZ_FMT PRIuMAX
51 static inline uintmax_t sz_fmt(size_t s) { return s; }
52
53 void pack_report(void)
54 {
55 fprintf(stderr,
56 "pack_report: getpagesize() = %10" SZ_FMT "\n"
57 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
58 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
59 sz_fmt(getpagesize()),
60 sz_fmt(packed_git_window_size),
61 sz_fmt(packed_git_limit));
62 fprintf(stderr,
63 "pack_report: pack_used_ctr = %10u\n"
64 "pack_report: pack_mmap_calls = %10u\n"
65 "pack_report: pack_open_windows = %10u / %10u\n"
66 "pack_report: pack_mapped = "
67 "%10" SZ_FMT " / %10" SZ_FMT "\n",
68 pack_used_ctr,
69 pack_mmap_calls,
70 pack_open_windows, peak_pack_open_windows,
71 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
72 }
73
74 /*
75 * Open and mmap the index file at path, perform a couple of
76 * consistency checks, then record its information to p. Return 0 on
77 * success.
78 */
79 static int check_packed_git_idx(const char *path, struct packed_git *p)
80 {
81 void *idx_map;
82 struct pack_idx_header *hdr;
83 size_t idx_size;
84 uint32_t version, nr, i, *index;
85 int fd = git_open(path);
86 struct stat st;
87
88 if (fd < 0)
89 return -1;
90 if (fstat(fd, &st)) {
91 close(fd);
92 return -1;
93 }
94 idx_size = xsize_t(st.st_size);
95 if (idx_size < 4 * 256 + 20 + 20) {
96 close(fd);
97 return error("index file %s is too small", path);
98 }
99 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
100 close(fd);
101
102 hdr = idx_map;
103 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
104 version = ntohl(hdr->idx_version);
105 if (version < 2 || version > 2) {
106 munmap(idx_map, idx_size);
107 return error("index file %s is version %"PRIu32
108 " and is not supported by this binary"
109 " (try upgrading GIT to a newer version)",
110 path, version);
111 }
112 } else
113 version = 1;
114
115 nr = 0;
116 index = idx_map;
117 if (version > 1)
118 index += 2; /* skip index header */
119 for (i = 0; i < 256; i++) {
120 uint32_t n = ntohl(index[i]);
121 if (n < nr) {
122 munmap(idx_map, idx_size);
123 return error("non-monotonic index %s", path);
124 }
125 nr = n;
126 }
127
128 if (version == 1) {
129 /*
130 * Total size:
131 * - 256 index entries 4 bytes each
132 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
133 * - 20-byte SHA1 of the packfile
134 * - 20-byte SHA1 file checksum
135 */
136 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
137 munmap(idx_map, idx_size);
138 return error("wrong index v1 file size in %s", path);
139 }
140 } else if (version == 2) {
141 /*
142 * Minimum size:
143 * - 8 bytes of header
144 * - 256 index entries 4 bytes each
145 * - 20-byte sha1 entry * nr
146 * - 4-byte crc entry * nr
147 * - 4-byte offset entry * nr
148 * - 20-byte SHA1 of the packfile
149 * - 20-byte SHA1 file checksum
150 * And after the 4-byte offset table might be a
151 * variable sized table containing 8-byte entries
152 * for offsets larger than 2^31.
153 */
154 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
155 unsigned long max_size = min_size;
156 if (nr)
157 max_size += (nr - 1)*8;
158 if (idx_size < min_size || idx_size > max_size) {
159 munmap(idx_map, idx_size);
160 return error("wrong index v2 file size in %s", path);
161 }
162 if (idx_size != min_size &&
163 /*
164 * make sure we can deal with large pack offsets.
165 * 31-bit signed offset won't be enough, neither
166 * 32-bit unsigned one will be.
167 */
168 (sizeof(off_t) <= 4)) {
169 munmap(idx_map, idx_size);
170 return error("pack too large for current definition of off_t in %s", path);
171 }
172 }
173
174 p->index_version = version;
175 p->index_data = idx_map;
176 p->index_size = idx_size;
177 p->num_objects = nr;
178 return 0;
179 }
180
181 int open_pack_index(struct packed_git *p)
182 {
183 char *idx_name;
184 size_t len;
185 int ret;
186
187 if (p->index_data)
188 return 0;
189
190 if (!strip_suffix(p->pack_name, ".pack", &len))
191 die("BUG: pack_name does not end in .pack");
192 idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
193 ret = check_packed_git_idx(idx_name, p);
194 free(idx_name);
195 return ret;
196 }
197
198 static struct packed_git *alloc_packed_git(int extra)
199 {
200 struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
201 memset(p, 0, sizeof(*p));
202 p->pack_fd = -1;
203 return p;
204 }
205
206 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
207 {
208 const char *path = sha1_pack_name(sha1);
209 size_t alloc = st_add(strlen(path), 1);
210 struct packed_git *p = alloc_packed_git(alloc);
211
212 memcpy(p->pack_name, path, alloc); /* includes NUL */
213 hashcpy(p->sha1, sha1);
214 if (check_packed_git_idx(idx_path, p)) {
215 free(p);
216 return NULL;
217 }
218
219 return p;
220 }
221
222 static void scan_windows(struct packed_git *p,
223 struct packed_git **lru_p,
224 struct pack_window **lru_w,
225 struct pack_window **lru_l)
226 {
227 struct pack_window *w, *w_l;
228
229 for (w_l = NULL, w = p->windows; w; w = w->next) {
230 if (!w->inuse_cnt) {
231 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
232 *lru_p = p;
233 *lru_w = w;
234 *lru_l = w_l;
235 }
236 }
237 w_l = w;
238 }
239 }
240
241 static int unuse_one_window(struct packed_git *current)
242 {
243 struct packed_git *p, *lru_p = NULL;
244 struct pack_window *lru_w = NULL, *lru_l = NULL;
245
246 if (current)
247 scan_windows(current, &lru_p, &lru_w, &lru_l);
248 for (p = the_repository->objects->packed_git; p; p = p->next)
249 scan_windows(p, &lru_p, &lru_w, &lru_l);
250 if (lru_p) {
251 munmap(lru_w->base, lru_w->len);
252 pack_mapped -= lru_w->len;
253 if (lru_l)
254 lru_l->next = lru_w->next;
255 else
256 lru_p->windows = lru_w->next;
257 free(lru_w);
258 pack_open_windows--;
259 return 1;
260 }
261 return 0;
262 }
263
264 void release_pack_memory(size_t need)
265 {
266 size_t cur = pack_mapped;
267 while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
268 ; /* nothing */
269 }
270
271 void close_pack_windows(struct packed_git *p)
272 {
273 while (p->windows) {
274 struct pack_window *w = p->windows;
275
276 if (w->inuse_cnt)
277 die("pack '%s' still has open windows to it",
278 p->pack_name);
279 munmap(w->base, w->len);
280 pack_mapped -= w->len;
281 pack_open_windows--;
282 p->windows = w->next;
283 free(w);
284 }
285 }
286
287 static int close_pack_fd(struct packed_git *p)
288 {
289 if (p->pack_fd < 0)
290 return 0;
291
292 close(p->pack_fd);
293 pack_open_fds--;
294 p->pack_fd = -1;
295
296 return 1;
297 }
298
299 void close_pack_index(struct packed_git *p)
300 {
301 if (p->index_data) {
302 munmap((void *)p->index_data, p->index_size);
303 p->index_data = NULL;
304 }
305 }
306
307 static void close_pack(struct packed_git *p)
308 {
309 close_pack_windows(p);
310 close_pack_fd(p);
311 close_pack_index(p);
312 }
313
314 void close_all_packs(struct raw_object_store *o)
315 {
316 struct packed_git *p;
317
318 for (p = o->packed_git; p; p = p->next)
319 if (p->do_not_close)
320 die("BUG: want to close pack marked 'do-not-close'");
321 else
322 close_pack(p);
323 }
324
325 /*
326 * The LRU pack is the one with the oldest MRU window, preferring packs
327 * with no used windows, or the oldest mtime if it has no windows allocated.
328 */
329 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
330 {
331 struct pack_window *w, *this_mru_w;
332 int has_windows_inuse = 0;
333
334 /*
335 * Reject this pack if it has windows and the previously selected
336 * one does not. If this pack does not have windows, reject
337 * it if the pack file is newer than the previously selected one.
338 */
339 if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
340 return;
341
342 for (w = this_mru_w = p->windows; w; w = w->next) {
343 /*
344 * Reject this pack if any of its windows are in use,
345 * but the previously selected pack did not have any
346 * inuse windows. Otherwise, record that this pack
347 * has windows in use.
348 */
349 if (w->inuse_cnt) {
350 if (*accept_windows_inuse)
351 has_windows_inuse = 1;
352 else
353 return;
354 }
355
356 if (w->last_used > this_mru_w->last_used)
357 this_mru_w = w;
358
359 /*
360 * Reject this pack if it has windows that have been
361 * used more recently than the previously selected pack.
362 * If the previously selected pack had windows inuse and
363 * we have not encountered a window in this pack that is
364 * inuse, skip this check since we prefer a pack with no
365 * inuse windows to one that has inuse windows.
366 */
367 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
368 this_mru_w->last_used > (*mru_w)->last_used)
369 return;
370 }
371
372 /*
373 * Select this pack.
374 */
375 *mru_w = this_mru_w;
376 *lru_p = p;
377 *accept_windows_inuse = has_windows_inuse;
378 }
379
380 static int close_one_pack(void)
381 {
382 struct packed_git *p, *lru_p = NULL;
383 struct pack_window *mru_w = NULL;
384 int accept_windows_inuse = 1;
385
386 for (p = the_repository->objects->packed_git; p; p = p->next) {
387 if (p->pack_fd == -1)
388 continue;
389 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
390 }
391
392 if (lru_p)
393 return close_pack_fd(lru_p);
394
395 return 0;
396 }
397
398 static unsigned int get_max_fd_limit(void)
399 {
400 #ifdef RLIMIT_NOFILE
401 {
402 struct rlimit lim;
403
404 if (!getrlimit(RLIMIT_NOFILE, &lim))
405 return lim.rlim_cur;
406 }
407 #endif
408
409 #ifdef _SC_OPEN_MAX
410 {
411 long open_max = sysconf(_SC_OPEN_MAX);
412 if (0 < open_max)
413 return open_max;
414 /*
415 * Otherwise, we got -1 for one of the two
416 * reasons:
417 *
418 * (1) sysconf() did not understand _SC_OPEN_MAX
419 * and signaled an error with -1; or
420 * (2) sysconf() said there is no limit.
421 *
422 * We _could_ clear errno before calling sysconf() to
423 * tell these two cases apart and return a huge number
424 * in the latter case to let the caller cap it to a
425 * value that is not so selfish, but letting the
426 * fallback OPEN_MAX codepath take care of these cases
427 * is a lot simpler.
428 */
429 }
430 #endif
431
432 #ifdef OPEN_MAX
433 return OPEN_MAX;
434 #else
435 return 1; /* see the caller ;-) */
436 #endif
437 }
438
439 /*
440 * Do not call this directly as this leaks p->pack_fd on error return;
441 * call open_packed_git() instead.
442 */
443 static int open_packed_git_1(struct packed_git *p)
444 {
445 struct stat st;
446 struct pack_header hdr;
447 unsigned char sha1[20];
448 unsigned char *idx_sha1;
449 long fd_flag;
450 ssize_t read_result;
451
452 if (!p->index_data && open_pack_index(p))
453 return error("packfile %s index unavailable", p->pack_name);
454
455 if (!pack_max_fds) {
456 unsigned int max_fds = get_max_fd_limit();
457
458 /* Save 3 for stdin/stdout/stderr, 22 for work */
459 if (25 < max_fds)
460 pack_max_fds = max_fds - 25;
461 else
462 pack_max_fds = 1;
463 }
464
465 while (pack_max_fds <= pack_open_fds && close_one_pack())
466 ; /* nothing */
467
468 p->pack_fd = git_open(p->pack_name);
469 if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
470 return -1;
471 pack_open_fds++;
472
473 /* If we created the struct before we had the pack we lack size. */
474 if (!p->pack_size) {
475 if (!S_ISREG(st.st_mode))
476 return error("packfile %s not a regular file", p->pack_name);
477 p->pack_size = st.st_size;
478 } else if (p->pack_size != st.st_size)
479 return error("packfile %s size changed", p->pack_name);
480
481 /* We leave these file descriptors open with sliding mmap;
482 * there is no point keeping them open across exec(), though.
483 */
484 fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
485 if (fd_flag < 0)
486 return error("cannot determine file descriptor flags");
487 fd_flag |= FD_CLOEXEC;
488 if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
489 return error("cannot set FD_CLOEXEC");
490
491 /* Verify we recognize this pack file format. */
492 read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
493 if (read_result < 0)
494 return error_errno("error reading from %s", p->pack_name);
495 if (read_result != sizeof(hdr))
496 return error("file %s is far too short to be a packfile", p->pack_name);
497 if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
498 return error("file %s is not a GIT packfile", p->pack_name);
499 if (!pack_version_ok(hdr.hdr_version))
500 return error("packfile %s is version %"PRIu32" and not"
501 " supported (try upgrading GIT to a newer version)",
502 p->pack_name, ntohl(hdr.hdr_version));
503
504 /* Verify the pack matches its index. */
505 if (p->num_objects != ntohl(hdr.hdr_entries))
506 return error("packfile %s claims to have %"PRIu32" objects"
507 " while index indicates %"PRIu32" objects",
508 p->pack_name, ntohl(hdr.hdr_entries),
509 p->num_objects);
510 if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
511 return error("end of packfile %s is unavailable", p->pack_name);
512 read_result = read_in_full(p->pack_fd, sha1, sizeof(sha1));
513 if (read_result < 0)
514 return error_errno("error reading from %s", p->pack_name);
515 if (read_result != sizeof(sha1))
516 return error("packfile %s signature is unavailable", p->pack_name);
517 idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
518 if (hashcmp(sha1, idx_sha1))
519 return error("packfile %s does not match index", p->pack_name);
520 return 0;
521 }
522
523 static int open_packed_git(struct packed_git *p)
524 {
525 if (!open_packed_git_1(p))
526 return 0;
527 close_pack_fd(p);
528 return -1;
529 }
530
531 static int in_window(struct pack_window *win, off_t offset)
532 {
533 /* We must promise at least 20 bytes (one hash) after the
534 * offset is available from this window, otherwise the offset
535 * is not actually in this window and a different window (which
536 * has that one hash excess) must be used. This is to support
537 * the object header and delta base parsing routines below.
538 */
539 off_t win_off = win->offset;
540 return win_off <= offset
541 && (offset + 20) <= (win_off + win->len);
542 }
543
544 unsigned char *use_pack(struct packed_git *p,
545 struct pack_window **w_cursor,
546 off_t offset,
547 unsigned long *left)
548 {
549 struct pack_window *win = *w_cursor;
550
551 /* Since packfiles end in a hash of their content and it's
552 * pointless to ask for an offset into the middle of that
553 * hash, and the in_window function above wouldn't match
554 * don't allow an offset too close to the end of the file.
555 */
556 if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
557 die("packfile %s cannot be accessed", p->pack_name);
558 if (offset > (p->pack_size - 20))
559 die("offset beyond end of packfile (truncated pack?)");
560 if (offset < 0)
561 die(_("offset before end of packfile (broken .idx?)"));
562
563 if (!win || !in_window(win, offset)) {
564 if (win)
565 win->inuse_cnt--;
566 for (win = p->windows; win; win = win->next) {
567 if (in_window(win, offset))
568 break;
569 }
570 if (!win) {
571 size_t window_align = packed_git_window_size / 2;
572 off_t len;
573
574 if (p->pack_fd == -1 && open_packed_git(p))
575 die("packfile %s cannot be accessed", p->pack_name);
576
577 win = xcalloc(1, sizeof(*win));
578 win->offset = (offset / window_align) * window_align;
579 len = p->pack_size - win->offset;
580 if (len > packed_git_window_size)
581 len = packed_git_window_size;
582 win->len = (size_t)len;
583 pack_mapped += win->len;
584 while (packed_git_limit < pack_mapped
585 && unuse_one_window(p))
586 ; /* nothing */
587 win->base = xmmap(NULL, win->len,
588 PROT_READ, MAP_PRIVATE,
589 p->pack_fd, win->offset);
590 if (win->base == MAP_FAILED)
591 die_errno("packfile %s cannot be mapped",
592 p->pack_name);
593 if (!win->offset && win->len == p->pack_size
594 && !p->do_not_close)
595 close_pack_fd(p);
596 pack_mmap_calls++;
597 pack_open_windows++;
598 if (pack_mapped > peak_pack_mapped)
599 peak_pack_mapped = pack_mapped;
600 if (pack_open_windows > peak_pack_open_windows)
601 peak_pack_open_windows = pack_open_windows;
602 win->next = p->windows;
603 p->windows = win;
604 }
605 }
606 if (win != *w_cursor) {
607 win->last_used = pack_used_ctr++;
608 win->inuse_cnt++;
609 *w_cursor = win;
610 }
611 offset -= win->offset;
612 if (left)
613 *left = win->len - xsize_t(offset);
614 return win->base + offset;
615 }
616
617 void unuse_pack(struct pack_window **w_cursor)
618 {
619 struct pack_window *w = *w_cursor;
620 if (w) {
621 w->inuse_cnt--;
622 *w_cursor = NULL;
623 }
624 }
625
626 static void try_to_free_pack_memory(size_t size)
627 {
628 release_pack_memory(size);
629 }
630
631 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
632 {
633 static int have_set_try_to_free_routine;
634 struct stat st;
635 size_t alloc;
636 struct packed_git *p;
637
638 if (!have_set_try_to_free_routine) {
639 have_set_try_to_free_routine = 1;
640 set_try_to_free_routine(try_to_free_pack_memory);
641 }
642
643 /*
644 * Make sure a corresponding .pack file exists and that
645 * the index looks sane.
646 */
647 if (!strip_suffix_mem(path, &path_len, ".idx"))
648 return NULL;
649
650 /*
651 * ".promisor" is long enough to hold any suffix we're adding (and
652 * the use xsnprintf double-checks that)
653 */
654 alloc = st_add3(path_len, strlen(".promisor"), 1);
655 p = alloc_packed_git(alloc);
656 memcpy(p->pack_name, path, path_len);
657
658 xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
659 if (!access(p->pack_name, F_OK))
660 p->pack_keep = 1;
661
662 xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
663 if (!access(p->pack_name, F_OK))
664 p->pack_promisor = 1;
665
666 xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
667 if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
668 free(p);
669 return NULL;
670 }
671
672 /* ok, it looks sane as far as we can check without
673 * actually mapping the pack file.
674 */
675 p->pack_size = st.st_size;
676 p->pack_local = local;
677 p->mtime = st.st_mtime;
678 if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
679 hashclr(p->sha1);
680 return p;
681 }
682
683 void install_packed_git(struct repository *r, struct packed_git *pack)
684 {
685 if (pack->pack_fd != -1)
686 pack_open_fds++;
687
688 pack->next = r->objects->packed_git;
689 r->objects->packed_git = pack;
690 }
691
692 void (*report_garbage)(unsigned seen_bits, const char *path);
693
694 static void report_helper(const struct string_list *list,
695 int seen_bits, int first, int last)
696 {
697 if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
698 return;
699
700 for (; first < last; first++)
701 report_garbage(seen_bits, list->items[first].string);
702 }
703
704 static void report_pack_garbage(struct string_list *list)
705 {
706 int i, baselen = -1, first = 0, seen_bits = 0;
707
708 if (!report_garbage)
709 return;
710
711 string_list_sort(list);
712
713 for (i = 0; i < list->nr; i++) {
714 const char *path = list->items[i].string;
715 if (baselen != -1 &&
716 strncmp(path, list->items[first].string, baselen)) {
717 report_helper(list, seen_bits, first, i);
718 baselen = -1;
719 seen_bits = 0;
720 }
721 if (baselen == -1) {
722 const char *dot = strrchr(path, '.');
723 if (!dot) {
724 report_garbage(PACKDIR_FILE_GARBAGE, path);
725 continue;
726 }
727 baselen = dot - path + 1;
728 first = i;
729 }
730 if (!strcmp(path + baselen, "pack"))
731 seen_bits |= 1;
732 else if (!strcmp(path + baselen, "idx"))
733 seen_bits |= 2;
734 }
735 report_helper(list, seen_bits, first, list->nr);
736 }
737
738 static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
739 {
740 struct strbuf path = STRBUF_INIT;
741 size_t dirnamelen;
742 DIR *dir;
743 struct dirent *de;
744 struct string_list garbage = STRING_LIST_INIT_DUP;
745
746 strbuf_addstr(&path, objdir);
747 strbuf_addstr(&path, "/pack");
748 dir = opendir(path.buf);
749 if (!dir) {
750 if (errno != ENOENT)
751 error_errno("unable to open object pack directory: %s",
752 path.buf);
753 strbuf_release(&path);
754 return;
755 }
756 strbuf_addch(&path, '/');
757 dirnamelen = path.len;
758 while ((de = readdir(dir)) != NULL) {
759 struct packed_git *p;
760 size_t base_len;
761
762 if (is_dot_or_dotdot(de->d_name))
763 continue;
764
765 strbuf_setlen(&path, dirnamelen);
766 strbuf_addstr(&path, de->d_name);
767
768 base_len = path.len;
769 if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
770 /* Don't reopen a pack we already have. */
771 for (p = r->objects->packed_git; p;
772 p = p->next) {
773 size_t len;
774 if (strip_suffix(p->pack_name, ".pack", &len) &&
775 len == base_len &&
776 !memcmp(p->pack_name, path.buf, len))
777 break;
778 }
779 if (p == NULL &&
780 /*
781 * See if it really is a valid .idx file with
782 * corresponding .pack file that we can map.
783 */
784 (p = add_packed_git(path.buf, path.len, local)) != NULL)
785 install_packed_git(r, p);
786 }
787
788 if (!report_garbage)
789 continue;
790
791 if (ends_with(de->d_name, ".idx") ||
792 ends_with(de->d_name, ".pack") ||
793 ends_with(de->d_name, ".bitmap") ||
794 ends_with(de->d_name, ".keep") ||
795 ends_with(de->d_name, ".promisor"))
796 string_list_append(&garbage, path.buf);
797 else
798 report_garbage(PACKDIR_FILE_GARBAGE, path.buf);
799 }
800 closedir(dir);
801 report_pack_garbage(&garbage);
802 string_list_clear(&garbage, 0);
803 strbuf_release(&path);
804 }
805
806 static void prepare_packed_git(struct repository *r);
807 /*
808 * Give a fast, rough count of the number of objects in the repository. This
809 * ignores loose objects completely. If you have a lot of them, then either
810 * you should repack because your performance will be awful, or they are
811 * all unreachable objects about to be pruned, in which case they're not really
812 * interesting as a measure of repo size in the first place.
813 */
814 unsigned long approximate_object_count(void)
815 {
816 if (!the_repository->objects->approximate_object_count_valid) {
817 unsigned long count;
818 struct packed_git *p;
819
820 prepare_packed_git(the_repository);
821 count = 0;
822 for (p = the_repository->objects->packed_git; p; p = p->next) {
823 if (open_pack_index(p))
824 continue;
825 count += p->num_objects;
826 }
827 the_repository->objects->approximate_object_count = count;
828 }
829 return the_repository->objects->approximate_object_count;
830 }
831
832 static void *get_next_packed_git(const void *p)
833 {
834 return ((const struct packed_git *)p)->next;
835 }
836
837 static void set_next_packed_git(void *p, void *next)
838 {
839 ((struct packed_git *)p)->next = next;
840 }
841
842 static int sort_pack(const void *a_, const void *b_)
843 {
844 const struct packed_git *a = a_;
845 const struct packed_git *b = b_;
846 int st;
847
848 /*
849 * Local packs tend to contain objects specific to our
850 * variant of the project than remote ones. In addition,
851 * remote ones could be on a network mounted filesystem.
852 * Favor local ones for these reasons.
853 */
854 st = a->pack_local - b->pack_local;
855 if (st)
856 return -st;
857
858 /*
859 * Younger packs tend to contain more recent objects,
860 * and more recent objects tend to get accessed more
861 * often.
862 */
863 if (a->mtime < b->mtime)
864 return 1;
865 else if (a->mtime == b->mtime)
866 return 0;
867 return -1;
868 }
869
870 static void rearrange_packed_git(struct repository *r)
871 {
872 r->objects->packed_git = llist_mergesort(
873 r->objects->packed_git, get_next_packed_git,
874 set_next_packed_git, sort_pack);
875 }
876
877 static void prepare_packed_git_mru(struct repository *r)
878 {
879 struct packed_git *p;
880
881 INIT_LIST_HEAD(&r->objects->packed_git_mru);
882
883 for (p = r->objects->packed_git; p; p = p->next)
884 list_add_tail(&p->mru, &r->objects->packed_git_mru);
885 }
886
887 static void prepare_packed_git(struct repository *r)
888 {
889 struct alternate_object_database *alt;
890
891 if (r->objects->packed_git_initialized)
892 return;
893 prepare_packed_git_one(r, r->objects->objectdir, 1);
894 prepare_alt_odb(r);
895 for (alt = r->objects->alt_odb_list; alt; alt = alt->next)
896 prepare_packed_git_one(r, alt->path, 0);
897 rearrange_packed_git(r);
898 prepare_packed_git_mru(r);
899 r->objects->packed_git_initialized = 1;
900 }
901
902 void reprepare_packed_git(struct repository *r)
903 {
904 r->objects->approximate_object_count_valid = 0;
905 r->objects->packed_git_initialized = 0;
906 prepare_packed_git(r);
907 }
908
909 struct packed_git *get_packed_git(struct repository *r)
910 {
911 prepare_packed_git(r);
912 return r->objects->packed_git;
913 }
914
915 struct list_head *get_packed_git_mru(struct repository *r)
916 {
917 prepare_packed_git(r);
918 return &r->objects->packed_git_mru;
919 }
920
921 unsigned long unpack_object_header_buffer(const unsigned char *buf,
922 unsigned long len, enum object_type *type, unsigned long *sizep)
923 {
924 unsigned shift;
925 unsigned long size, c;
926 unsigned long used = 0;
927
928 c = buf[used++];
929 *type = (c >> 4) & 7;
930 size = c & 15;
931 shift = 4;
932 while (c & 0x80) {
933 if (len <= used || bitsizeof(long) <= shift) {
934 error("bad object header");
935 size = used = 0;
936 break;
937 }
938 c = buf[used++];
939 size += (c & 0x7f) << shift;
940 shift += 7;
941 }
942 *sizep = size;
943 return used;
944 }
945
946 unsigned long get_size_from_delta(struct packed_git *p,
947 struct pack_window **w_curs,
948 off_t curpos)
949 {
950 const unsigned char *data;
951 unsigned char delta_head[20], *in;
952 git_zstream stream;
953 int st;
954
955 memset(&stream, 0, sizeof(stream));
956 stream.next_out = delta_head;
957 stream.avail_out = sizeof(delta_head);
958
959 git_inflate_init(&stream);
960 do {
961 in = use_pack(p, w_curs, curpos, &stream.avail_in);
962 stream.next_in = in;
963 st = git_inflate(&stream, Z_FINISH);
964 curpos += stream.next_in - in;
965 } while ((st == Z_OK || st == Z_BUF_ERROR) &&
966 stream.total_out < sizeof(delta_head));
967 git_inflate_end(&stream);
968 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
969 error("delta data unpack-initial failed");
970 return 0;
971 }
972
973 /* Examine the initial part of the delta to figure out
974 * the result size.
975 */
976 data = delta_head;
977
978 /* ignore base size */
979 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
980
981 /* Read the result size */
982 return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
983 }
984
985 int unpack_object_header(struct packed_git *p,
986 struct pack_window **w_curs,
987 off_t *curpos,
988 unsigned long *sizep)
989 {
990 unsigned char *base;
991 unsigned long left;
992 unsigned long used;
993 enum object_type type;
994
995 /* use_pack() assures us we have [base, base + 20) available
996 * as a range that we can look at. (Its actually the hash
997 * size that is assured.) With our object header encoding
998 * the maximum deflated object size is 2^137, which is just
999 * insane, so we know won't exceed what we have been given.
1000 */
1001 base = use_pack(p, w_curs, *curpos, &left);
1002 used = unpack_object_header_buffer(base, left, &type, sizep);
1003 if (!used) {
1004 type = OBJ_BAD;
1005 } else
1006 *curpos += used;
1007
1008 return type;
1009 }
1010
1011 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1012 {
1013 unsigned i;
1014 for (i = 0; i < p->num_bad_objects; i++)
1015 if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
1016 return;
1017 p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1018 st_mult(GIT_MAX_RAWSZ,
1019 st_add(p->num_bad_objects, 1)));
1020 hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
1021 p->num_bad_objects++;
1022 }
1023
1024 const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1025 {
1026 struct packed_git *p;
1027 unsigned i;
1028
1029 for (p = the_repository->objects->packed_git; p; p = p->next)
1030 for (i = 0; i < p->num_bad_objects; i++)
1031 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1032 return p;
1033 return NULL;
1034 }
1035
1036 static off_t get_delta_base(struct packed_git *p,
1037 struct pack_window **w_curs,
1038 off_t *curpos,
1039 enum object_type type,
1040 off_t delta_obj_offset)
1041 {
1042 unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1043 off_t base_offset;
1044
1045 /* use_pack() assured us we have [base_info, base_info + 20)
1046 * as a range that we can look at without walking off the
1047 * end of the mapped window. Its actually the hash size
1048 * that is assured. An OFS_DELTA longer than the hash size
1049 * is stupid, as then a REF_DELTA would be smaller to store.
1050 */
1051 if (type == OBJ_OFS_DELTA) {
1052 unsigned used = 0;
1053 unsigned char c = base_info[used++];
1054 base_offset = c & 127;
1055 while (c & 128) {
1056 base_offset += 1;
1057 if (!base_offset || MSB(base_offset, 7))
1058 return 0; /* overflow */
1059 c = base_info[used++];
1060 base_offset = (base_offset << 7) + (c & 127);
1061 }
1062 base_offset = delta_obj_offset - base_offset;
1063 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1064 return 0; /* out of bound */
1065 *curpos += used;
1066 } else if (type == OBJ_REF_DELTA) {
1067 /* The base entry _must_ be in the same pack */
1068 base_offset = find_pack_entry_one(base_info, p);
1069 *curpos += 20;
1070 } else
1071 die("I am totally screwed");
1072 return base_offset;
1073 }
1074
1075 /*
1076 * Like get_delta_base above, but we return the sha1 instead of the pack
1077 * offset. This means it is cheaper for REF deltas (we do not have to do
1078 * the final object lookup), but more expensive for OFS deltas (we
1079 * have to load the revidx to convert the offset back into a sha1).
1080 */
1081 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1082 struct pack_window **w_curs,
1083 off_t curpos,
1084 enum object_type type,
1085 off_t delta_obj_offset)
1086 {
1087 if (type == OBJ_REF_DELTA) {
1088 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1089 return base;
1090 } else if (type == OBJ_OFS_DELTA) {
1091 struct revindex_entry *revidx;
1092 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1093 type, delta_obj_offset);
1094
1095 if (!base_offset)
1096 return NULL;
1097
1098 revidx = find_pack_revindex(p, base_offset);
1099 if (!revidx)
1100 return NULL;
1101
1102 return nth_packed_object_sha1(p, revidx->nr);
1103 } else
1104 return NULL;
1105 }
1106
1107 #define retry_bad_packed_offset(r, p, o) \
1108 retry_bad_packed_offset_##r(p, o)
1109 static int retry_bad_packed_offset_the_repository(struct packed_git *p, off_t obj_offset)
1110 {
1111 int type;
1112 struct revindex_entry *revidx;
1113 struct object_id oid;
1114 revidx = find_pack_revindex(p, obj_offset);
1115 if (!revidx)
1116 return OBJ_BAD;
1117 nth_packed_object_oid(&oid, p, revidx->nr);
1118 mark_bad_packed_object(p, oid.hash);
1119 type = oid_object_info(the_repository, &oid, NULL);
1120 if (type <= OBJ_NONE)
1121 return OBJ_BAD;
1122 return type;
1123 }
1124
1125 #define POI_STACK_PREALLOC 64
1126
1127 #define packed_to_object_type(r, p, o, t, w, c) \
1128 packed_to_object_type_##r(p, o, t, w, c)
1129 static enum object_type packed_to_object_type_the_repository(struct packed_git *p,
1130 off_t obj_offset,
1131 enum object_type type,
1132 struct pack_window **w_curs,
1133 off_t curpos)
1134 {
1135 off_t small_poi_stack[POI_STACK_PREALLOC];
1136 off_t *poi_stack = small_poi_stack;
1137 int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1138
1139 while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1140 off_t base_offset;
1141 unsigned long size;
1142 /* Push the object we're going to leave behind */
1143 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1144 poi_stack_alloc = alloc_nr(poi_stack_nr);
1145 ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1146 memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1147 } else {
1148 ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1149 }
1150 poi_stack[poi_stack_nr++] = obj_offset;
1151 /* If parsing the base offset fails, just unwind */
1152 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1153 if (!base_offset)
1154 goto unwind;
1155 curpos = obj_offset = base_offset;
1156 type = unpack_object_header(p, w_curs, &curpos, &size);
1157 if (type <= OBJ_NONE) {
1158 /* If getting the base itself fails, we first
1159 * retry the base, otherwise unwind */
1160 type = retry_bad_packed_offset(the_repository, p, base_offset);
1161 if (type > OBJ_NONE)
1162 goto out;
1163 goto unwind;
1164 }
1165 }
1166
1167 switch (type) {
1168 case OBJ_BAD:
1169 case OBJ_COMMIT:
1170 case OBJ_TREE:
1171 case OBJ_BLOB:
1172 case OBJ_TAG:
1173 break;
1174 default:
1175 error("unknown object type %i at offset %"PRIuMAX" in %s",
1176 type, (uintmax_t)obj_offset, p->pack_name);
1177 type = OBJ_BAD;
1178 }
1179
1180 out:
1181 if (poi_stack != small_poi_stack)
1182 free(poi_stack);
1183 return type;
1184
1185 unwind:
1186 while (poi_stack_nr) {
1187 obj_offset = poi_stack[--poi_stack_nr];
1188 type = retry_bad_packed_offset(the_repository, p, obj_offset);
1189 if (type > OBJ_NONE)
1190 goto out;
1191 }
1192 type = OBJ_BAD;
1193 goto out;
1194 }
1195
1196 static struct hashmap delta_base_cache;
1197 static size_t delta_base_cached;
1198
1199 static LIST_HEAD(delta_base_cache_lru);
1200
1201 struct delta_base_cache_key {
1202 struct packed_git *p;
1203 off_t base_offset;
1204 };
1205
1206 struct delta_base_cache_entry {
1207 struct hashmap hash;
1208 struct delta_base_cache_key key;
1209 struct list_head lru;
1210 void *data;
1211 unsigned long size;
1212 enum object_type type;
1213 };
1214
1215 static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1216 {
1217 unsigned int hash;
1218
1219 hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1220 hash += (hash >> 8) + (hash >> 16);
1221 return hash;
1222 }
1223
1224 static struct delta_base_cache_entry *
1225 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1226 {
1227 struct hashmap_entry entry;
1228 struct delta_base_cache_key key;
1229
1230 if (!delta_base_cache.cmpfn)
1231 return NULL;
1232
1233 hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1234 key.p = p;
1235 key.base_offset = base_offset;
1236 return hashmap_get(&delta_base_cache, &entry, &key);
1237 }
1238
1239 static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
1240 const struct delta_base_cache_key *b)
1241 {
1242 return a->p == b->p && a->base_offset == b->base_offset;
1243 }
1244
1245 static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
1246 const void *va, const void *vb,
1247 const void *vkey)
1248 {
1249 const struct delta_base_cache_entry *a = va, *b = vb;
1250 const struct delta_base_cache_key *key = vkey;
1251 if (key)
1252 return !delta_base_cache_key_eq(&a->key, key);
1253 else
1254 return !delta_base_cache_key_eq(&a->key, &b->key);
1255 }
1256
1257 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1258 {
1259 return !!get_delta_base_cache_entry(p, base_offset);
1260 }
1261
1262 /*
1263 * Remove the entry from the cache, but do _not_ free the associated
1264 * entry data. The caller takes ownership of the "data" buffer, and
1265 * should copy out any fields it wants before detaching.
1266 */
1267 static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1268 {
1269 hashmap_remove(&delta_base_cache, ent, &ent->key);
1270 list_del(&ent->lru);
1271 delta_base_cached -= ent->size;
1272 free(ent);
1273 }
1274
1275 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1276 unsigned long *base_size, enum object_type *type)
1277 {
1278 struct delta_base_cache_entry *ent;
1279
1280 ent = get_delta_base_cache_entry(p, base_offset);
1281 if (!ent)
1282 return unpack_entry(p, base_offset, type, base_size);
1283
1284 if (type)
1285 *type = ent->type;
1286 if (base_size)
1287 *base_size = ent->size;
1288 return xmemdupz(ent->data, ent->size);
1289 }
1290
1291 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1292 {
1293 free(ent->data);
1294 detach_delta_base_cache_entry(ent);
1295 }
1296
1297 void clear_delta_base_cache(void)
1298 {
1299 struct list_head *lru, *tmp;
1300 list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1301 struct delta_base_cache_entry *entry =
1302 list_entry(lru, struct delta_base_cache_entry, lru);
1303 release_delta_base_cache(entry);
1304 }
1305 }
1306
1307 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1308 void *base, unsigned long base_size, enum object_type type)
1309 {
1310 struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1311 struct list_head *lru, *tmp;
1312
1313 delta_base_cached += base_size;
1314
1315 list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1316 struct delta_base_cache_entry *f =
1317 list_entry(lru, struct delta_base_cache_entry, lru);
1318 if (delta_base_cached <= delta_base_cache_limit)
1319 break;
1320 release_delta_base_cache(f);
1321 }
1322
1323 ent->key.p = p;
1324 ent->key.base_offset = base_offset;
1325 ent->type = type;
1326 ent->data = base;
1327 ent->size = base_size;
1328 list_add_tail(&ent->lru, &delta_base_cache_lru);
1329
1330 if (!delta_base_cache.cmpfn)
1331 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1332 hashmap_entry_init(ent, pack_entry_hash(p, base_offset));
1333 hashmap_add(&delta_base_cache, ent);
1334 }
1335
1336 int packed_object_info_the_repository(struct packed_git *p, off_t obj_offset,
1337 struct object_info *oi)
1338 {
1339 struct pack_window *w_curs = NULL;
1340 unsigned long size;
1341 off_t curpos = obj_offset;
1342 enum object_type type;
1343
1344 /*
1345 * We always get the representation type, but only convert it to
1346 * a "real" type later if the caller is interested.
1347 */
1348 if (oi->contentp) {
1349 *oi->contentp = cache_or_unpack_entry(p, obj_offset, oi->sizep,
1350 &type);
1351 if (!*oi->contentp)
1352 type = OBJ_BAD;
1353 } else {
1354 type = unpack_object_header(p, &w_curs, &curpos, &size);
1355 }
1356
1357 if (!oi->contentp && oi->sizep) {
1358 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1359 off_t tmp_pos = curpos;
1360 off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1361 type, obj_offset);
1362 if (!base_offset) {
1363 type = OBJ_BAD;
1364 goto out;
1365 }
1366 *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1367 if (*oi->sizep == 0) {
1368 type = OBJ_BAD;
1369 goto out;
1370 }
1371 } else {
1372 *oi->sizep = size;
1373 }
1374 }
1375
1376 if (oi->disk_sizep) {
1377 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1378 *oi->disk_sizep = revidx[1].offset - obj_offset;
1379 }
1380
1381 if (oi->typep || oi->type_name) {
1382 enum object_type ptot;
1383 ptot = packed_to_object_type(the_repository, p, obj_offset,
1384 type, &w_curs, curpos);
1385 if (oi->typep)
1386 *oi->typep = ptot;
1387 if (oi->type_name) {
1388 const char *tn = type_name(ptot);
1389 if (tn)
1390 strbuf_addstr(oi->type_name, tn);
1391 }
1392 if (ptot < 0) {
1393 type = OBJ_BAD;
1394 goto out;
1395 }
1396 }
1397
1398 if (oi->delta_base_sha1) {
1399 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1400 const unsigned char *base;
1401
1402 base = get_delta_base_sha1(p, &w_curs, curpos,
1403 type, obj_offset);
1404 if (!base) {
1405 type = OBJ_BAD;
1406 goto out;
1407 }
1408
1409 hashcpy(oi->delta_base_sha1, base);
1410 } else
1411 hashclr(oi->delta_base_sha1);
1412 }
1413
1414 oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1415 OI_PACKED;
1416
1417 out:
1418 unuse_pack(&w_curs);
1419 return type;
1420 }
1421
1422 static void *unpack_compressed_entry(struct packed_git *p,
1423 struct pack_window **w_curs,
1424 off_t curpos,
1425 unsigned long size)
1426 {
1427 int st;
1428 git_zstream stream;
1429 unsigned char *buffer, *in;
1430
1431 buffer = xmallocz_gently(size);
1432 if (!buffer)
1433 return NULL;
1434 memset(&stream, 0, sizeof(stream));
1435 stream.next_out = buffer;
1436 stream.avail_out = size + 1;
1437
1438 git_inflate_init(&stream);
1439 do {
1440 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1441 stream.next_in = in;
1442 st = git_inflate(&stream, Z_FINISH);
1443 if (!stream.avail_out)
1444 break; /* the payload is larger than it should be */
1445 curpos += stream.next_in - in;
1446 } while (st == Z_OK || st == Z_BUF_ERROR);
1447 git_inflate_end(&stream);
1448 if ((st != Z_STREAM_END) || stream.total_out != size) {
1449 free(buffer);
1450 return NULL;
1451 }
1452
1453 return buffer;
1454 }
1455
1456 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1457 {
1458 static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1459 trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1460 p->pack_name, (uintmax_t)obj_offset);
1461 }
1462
1463 int do_check_packed_object_crc;
1464
1465 #define UNPACK_ENTRY_STACK_PREALLOC 64
1466 struct unpack_entry_stack_ent {
1467 off_t obj_offset;
1468 off_t curpos;
1469 unsigned long size;
1470 };
1471
1472 static void *read_object(const struct object_id *oid, enum object_type *type,
1473 unsigned long *size)
1474 {
1475 struct object_info oi = OBJECT_INFO_INIT;
1476 void *content;
1477 oi.typep = type;
1478 oi.sizep = size;
1479 oi.contentp = &content;
1480
1481 if (oid_object_info_extended(the_repository, oid, &oi, 0) < 0)
1482 return NULL;
1483 return content;
1484 }
1485
1486 void *unpack_entry(struct packed_git *p, off_t obj_offset,
1487 enum object_type *final_type, unsigned long *final_size)
1488 {
1489 struct pack_window *w_curs = NULL;
1490 off_t curpos = obj_offset;
1491 void *data = NULL;
1492 unsigned long size;
1493 enum object_type type;
1494 struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1495 struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1496 int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1497 int base_from_cache = 0;
1498
1499 write_pack_access_log(p, obj_offset);
1500
1501 /* PHASE 1: drill down to the innermost base object */
1502 for (;;) {
1503 off_t base_offset;
1504 int i;
1505 struct delta_base_cache_entry *ent;
1506
1507 ent = get_delta_base_cache_entry(p, curpos);
1508 if (ent) {
1509 type = ent->type;
1510 data = ent->data;
1511 size = ent->size;
1512 detach_delta_base_cache_entry(ent);
1513 base_from_cache = 1;
1514 break;
1515 }
1516
1517 if (do_check_packed_object_crc && p->index_version > 1) {
1518 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1519 off_t len = revidx[1].offset - obj_offset;
1520 if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1521 struct object_id oid;
1522 nth_packed_object_oid(&oid, p, revidx->nr);
1523 error("bad packed object CRC for %s",
1524 oid_to_hex(&oid));
1525 mark_bad_packed_object(p, oid.hash);
1526 data = NULL;
1527 goto out;
1528 }
1529 }
1530
1531 type = unpack_object_header(p, &w_curs, &curpos, &size);
1532 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1533 break;
1534
1535 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1536 if (!base_offset) {
1537 error("failed to validate delta base reference "
1538 "at offset %"PRIuMAX" from %s",
1539 (uintmax_t)curpos, p->pack_name);
1540 /* bail to phase 2, in hopes of recovery */
1541 data = NULL;
1542 break;
1543 }
1544
1545 /* push object, proceed to base */
1546 if (delta_stack_nr >= delta_stack_alloc
1547 && delta_stack == small_delta_stack) {
1548 delta_stack_alloc = alloc_nr(delta_stack_nr);
1549 ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1550 memcpy(delta_stack, small_delta_stack,
1551 sizeof(*delta_stack)*delta_stack_nr);
1552 } else {
1553 ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1554 }
1555 i = delta_stack_nr++;
1556 delta_stack[i].obj_offset = obj_offset;
1557 delta_stack[i].curpos = curpos;
1558 delta_stack[i].size = size;
1559
1560 curpos = obj_offset = base_offset;
1561 }
1562
1563 /* PHASE 2: handle the base */
1564 switch (type) {
1565 case OBJ_OFS_DELTA:
1566 case OBJ_REF_DELTA:
1567 if (data)
1568 die("BUG: unpack_entry: left loop at a valid delta");
1569 break;
1570 case OBJ_COMMIT:
1571 case OBJ_TREE:
1572 case OBJ_BLOB:
1573 case OBJ_TAG:
1574 if (!base_from_cache)
1575 data = unpack_compressed_entry(p, &w_curs, curpos, size);
1576 break;
1577 default:
1578 data = NULL;
1579 error("unknown object type %i at offset %"PRIuMAX" in %s",
1580 type, (uintmax_t)obj_offset, p->pack_name);
1581 }
1582
1583 /* PHASE 3: apply deltas in order */
1584
1585 /* invariants:
1586 * 'data' holds the base data, or NULL if there was corruption
1587 */
1588 while (delta_stack_nr) {
1589 void *delta_data;
1590 void *base = data;
1591 void *external_base = NULL;
1592 unsigned long delta_size, base_size = size;
1593 int i;
1594
1595 data = NULL;
1596
1597 if (base)
1598 add_delta_base_cache(p, obj_offset, base, base_size, type);
1599
1600 if (!base) {
1601 /*
1602 * We're probably in deep shit, but let's try to fetch
1603 * the required base anyway from another pack or loose.
1604 * This is costly but should happen only in the presence
1605 * of a corrupted pack, and is better than failing outright.
1606 */
1607 struct revindex_entry *revidx;
1608 struct object_id base_oid;
1609 revidx = find_pack_revindex(p, obj_offset);
1610 if (revidx) {
1611 nth_packed_object_oid(&base_oid, p, revidx->nr);
1612 error("failed to read delta base object %s"
1613 " at offset %"PRIuMAX" from %s",
1614 oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1615 p->pack_name);
1616 mark_bad_packed_object(p, base_oid.hash);
1617 base = read_object(&base_oid, &type, &base_size);
1618 external_base = base;
1619 }
1620 }
1621
1622 i = --delta_stack_nr;
1623 obj_offset = delta_stack[i].obj_offset;
1624 curpos = delta_stack[i].curpos;
1625 delta_size = delta_stack[i].size;
1626
1627 if (!base)
1628 continue;
1629
1630 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1631
1632 if (!delta_data) {
1633 error("failed to unpack compressed delta "
1634 "at offset %"PRIuMAX" from %s",
1635 (uintmax_t)curpos, p->pack_name);
1636 data = NULL;
1637 free(external_base);
1638 continue;
1639 }
1640
1641 data = patch_delta(base, base_size,
1642 delta_data, delta_size,
1643 &size);
1644
1645 /*
1646 * We could not apply the delta; warn the user, but keep going.
1647 * Our failure will be noticed either in the next iteration of
1648 * the loop, or if this is the final delta, in the caller when
1649 * we return NULL. Those code paths will take care of making
1650 * a more explicit warning and retrying with another copy of
1651 * the object.
1652 */
1653 if (!data)
1654 error("failed to apply delta");
1655
1656 free(delta_data);
1657 free(external_base);
1658 }
1659
1660 if (final_type)
1661 *final_type = type;
1662 if (final_size)
1663 *final_size = size;
1664
1665 out:
1666 unuse_pack(&w_curs);
1667
1668 if (delta_stack != small_delta_stack)
1669 free(delta_stack);
1670
1671 return data;
1672 }
1673
1674 int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1675 {
1676 const unsigned char *index_fanout = p->index_data;
1677 const unsigned char *index_lookup;
1678 int index_lookup_width;
1679
1680 if (!index_fanout)
1681 BUG("bsearch_pack called without a valid pack-index");
1682
1683 index_lookup = index_fanout + 4 * 256;
1684 if (p->index_version == 1) {
1685 index_lookup_width = 24;
1686 index_lookup += 4;
1687 } else {
1688 index_lookup_width = 20;
1689 index_fanout += 8;
1690 index_lookup += 8;
1691 }
1692
1693 return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1694 index_lookup, index_lookup_width, result);
1695 }
1696
1697 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1698 uint32_t n)
1699 {
1700 const unsigned char *index = p->index_data;
1701 if (!index) {
1702 if (open_pack_index(p))
1703 return NULL;
1704 index = p->index_data;
1705 }
1706 if (n >= p->num_objects)
1707 return NULL;
1708 index += 4 * 256;
1709 if (p->index_version == 1) {
1710 return index + 24 * n + 4;
1711 } else {
1712 index += 8;
1713 return index + 20 * n;
1714 }
1715 }
1716
1717 const struct object_id *nth_packed_object_oid(struct object_id *oid,
1718 struct packed_git *p,
1719 uint32_t n)
1720 {
1721 const unsigned char *hash = nth_packed_object_sha1(p, n);
1722 if (!hash)
1723 return NULL;
1724 hashcpy(oid->hash, hash);
1725 return oid;
1726 }
1727
1728 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1729 {
1730 const unsigned char *ptr = vptr;
1731 const unsigned char *start = p->index_data;
1732 const unsigned char *end = start + p->index_size;
1733 if (ptr < start)
1734 die(_("offset before start of pack index for %s (corrupt index?)"),
1735 p->pack_name);
1736 /* No need to check for underflow; .idx files must be at least 8 bytes */
1737 if (ptr >= end - 8)
1738 die(_("offset beyond end of pack index for %s (truncated index?)"),
1739 p->pack_name);
1740 }
1741
1742 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1743 {
1744 const unsigned char *index = p->index_data;
1745 index += 4 * 256;
1746 if (p->index_version == 1) {
1747 return ntohl(*((uint32_t *)(index + 24 * n)));
1748 } else {
1749 uint32_t off;
1750 index += 8 + p->num_objects * (20 + 4);
1751 off = ntohl(*((uint32_t *)(index + 4 * n)));
1752 if (!(off & 0x80000000))
1753 return off;
1754 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1755 check_pack_index_ptr(p, index);
1756 return get_be64(index);
1757 }
1758 }
1759
1760 off_t find_pack_entry_one(const unsigned char *sha1,
1761 struct packed_git *p)
1762 {
1763 const unsigned char *index = p->index_data;
1764 struct object_id oid;
1765 uint32_t result;
1766
1767 if (!index) {
1768 if (open_pack_index(p))
1769 return 0;
1770 }
1771
1772 hashcpy(oid.hash, sha1);
1773 if (bsearch_pack(&oid, p, &result))
1774 return nth_packed_object_offset(p, result);
1775 return 0;
1776 }
1777
1778 int is_pack_valid(struct packed_git *p)
1779 {
1780 /* An already open pack is known to be valid. */
1781 if (p->pack_fd != -1)
1782 return 1;
1783
1784 /* If the pack has one window completely covering the
1785 * file size, the pack is known to be valid even if
1786 * the descriptor is not currently open.
1787 */
1788 if (p->windows) {
1789 struct pack_window *w = p->windows;
1790
1791 if (!w->offset && w->len == p->pack_size)
1792 return 1;
1793 }
1794
1795 /* Force the pack to open to prove its valid. */
1796 return !open_packed_git(p);
1797 }
1798
1799 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1800 struct packed_git *packs)
1801 {
1802 struct packed_git *p;
1803
1804 for (p = packs; p; p = p->next) {
1805 if (find_pack_entry_one(sha1, p))
1806 return p;
1807 }
1808 return NULL;
1809
1810 }
1811
1812 static int fill_pack_entry(const unsigned char *sha1,
1813 struct pack_entry *e,
1814 struct packed_git *p)
1815 {
1816 off_t offset;
1817
1818 if (p->num_bad_objects) {
1819 unsigned i;
1820 for (i = 0; i < p->num_bad_objects; i++)
1821 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1822 return 0;
1823 }
1824
1825 offset = find_pack_entry_one(sha1, p);
1826 if (!offset)
1827 return 0;
1828
1829 /*
1830 * We are about to tell the caller where they can locate the
1831 * requested object. We better make sure the packfile is
1832 * still here and can be accessed before supplying that
1833 * answer, as it may have been deleted since the index was
1834 * loaded!
1835 */
1836 if (!is_pack_valid(p))
1837 return 0;
1838 e->offset = offset;
1839 e->p = p;
1840 hashcpy(e->sha1, sha1);
1841 return 1;
1842 }
1843
1844 int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack_entry *e)
1845 {
1846 struct list_head *pos;
1847
1848 prepare_packed_git(r);
1849 if (!r->objects->packed_git)
1850 return 0;
1851
1852 list_for_each(pos, &r->objects->packed_git_mru) {
1853 struct packed_git *p = list_entry(pos, struct packed_git, mru);
1854 if (fill_pack_entry(sha1, e, p)) {
1855 list_move(&p->mru, &r->objects->packed_git_mru);
1856 return 1;
1857 }
1858 }
1859 return 0;
1860 }
1861
1862 int has_sha1_pack(const unsigned char *sha1)
1863 {
1864 struct pack_entry e;
1865 return find_pack_entry(the_repository, sha1, &e);
1866 }
1867
1868 int has_pack_index(const unsigned char *sha1)
1869 {
1870 struct stat st;
1871 if (stat(sha1_pack_index_name(sha1), &st))
1872 return 0;
1873 return 1;
1874 }
1875
1876 static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
1877 {
1878 uint32_t i;
1879 int r = 0;
1880
1881 for (i = 0; i < p->num_objects; i++) {
1882 struct object_id oid;
1883
1884 if (!nth_packed_object_oid(&oid, p, i))
1885 return error("unable to get sha1 of object %u in %s",
1886 i, p->pack_name);
1887
1888 r = cb(&oid, p, i, data);
1889 if (r)
1890 break;
1891 }
1892 return r;
1893 }
1894
1895 int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
1896 {
1897 struct packed_git *p;
1898 int r = 0;
1899 int pack_errors = 0;
1900
1901 prepare_packed_git(the_repository);
1902 for (p = the_repository->objects->packed_git; p; p = p->next) {
1903 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
1904 continue;
1905 if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
1906 !p->pack_promisor)
1907 continue;
1908 if (open_pack_index(p)) {
1909 pack_errors = 1;
1910 continue;
1911 }
1912 r = for_each_object_in_pack(p, cb, data);
1913 if (r)
1914 break;
1915 }
1916 return r ? r : pack_errors;
1917 }
1918
1919 static int add_promisor_object(const struct object_id *oid,
1920 struct packed_git *pack,
1921 uint32_t pos,
1922 void *set_)
1923 {
1924 struct oidset *set = set_;
1925 struct object *obj = parse_object(oid);
1926 if (!obj)
1927 return 1;
1928
1929 oidset_insert(set, oid);
1930
1931 /*
1932 * If this is a tree, commit, or tag, the objects it refers
1933 * to are also promisor objects. (Blobs refer to no objects->)
1934 */
1935 if (obj->type == OBJ_TREE) {
1936 struct tree *tree = (struct tree *)obj;
1937 struct tree_desc desc;
1938 struct name_entry entry;
1939 if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
1940 /*
1941 * Error messages are given when packs are
1942 * verified, so do not print any here.
1943 */
1944 return 0;
1945 while (tree_entry_gently(&desc, &entry))
1946 oidset_insert(set, entry.oid);
1947 } else if (obj->type == OBJ_COMMIT) {
1948 struct commit *commit = (struct commit *) obj;
1949 struct commit_list *parents = commit->parents;
1950
1951 oidset_insert(set, &commit->tree->object.oid);
1952 for (; parents; parents = parents->next)
1953 oidset_insert(set, &parents->item->object.oid);
1954 } else if (obj->type == OBJ_TAG) {
1955 struct tag *tag = (struct tag *) obj;
1956 oidset_insert(set, &tag->tagged->oid);
1957 }
1958 return 0;
1959 }
1960
1961 int is_promisor_object(const struct object_id *oid)
1962 {
1963 static struct oidset promisor_objects;
1964 static int promisor_objects_prepared;
1965
1966 if (!promisor_objects_prepared) {
1967 if (repository_format_partial_clone) {
1968 for_each_packed_object(add_promisor_object,
1969 &promisor_objects,
1970 FOR_EACH_OBJECT_PROMISOR_ONLY);
1971 }
1972 promisor_objects_prepared = 1;
1973 }
1974 return oidset_contains(&promisor_objects, oid);
1975 }