extension.partialclone: introduce partial clone extension
[git/git.git] / packfile.c
CommitLineData
4f39cd82 1#include "cache.h"
6d6a80e0 2#include "mru.h"
0317f455 3#include "pack.h"
0abe14f6
JT
4#include "dir.h"
5#include "mergesort.h"
6#include "packfile.h"
7b3aa75d 7#include "delta.h"
f1d8130b
JT
8#include "list.h"
9#include "streaming.h"
a2551953 10#include "sha1-lookup.h"
4f39cd82
JT
11
12char *odb_pack_name(struct strbuf *buf,
13 const unsigned char *sha1,
14 const char *ext)
15{
16 strbuf_reset(buf);
17 strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
18 sha1_to_hex(sha1), ext);
19 return buf->buf;
20}
21
22char *sha1_pack_name(const unsigned char *sha1)
23{
24 static struct strbuf buf = STRBUF_INIT;
25 return odb_pack_name(&buf, sha1, "pack");
26}
27
28char *sha1_pack_index_name(const unsigned char *sha1)
29{
30 static struct strbuf buf = STRBUF_INIT;
31 return odb_pack_name(&buf, sha1, "idx");
32}
6d6a80e0 33
84f80ad5
JT
34static unsigned int pack_used_ctr;
35static unsigned int pack_mmap_calls;
36static unsigned int peak_pack_open_windows;
37static unsigned int pack_open_windows;
e65f1862 38static unsigned int pack_open_fds;
84f80ad5
JT
39static unsigned int pack_max_fds;
40static size_t peak_pack_mapped;
41static size_t pack_mapped;
6d6a80e0 42struct packed_git *packed_git;
607bd831 43struct mru packed_git_mru;
8e21176c
JT
44
45#define SZ_FMT PRIuMAX
46static inline uintmax_t sz_fmt(size_t s) { return s; }
47
48void pack_report(void)
49{
50 fprintf(stderr,
51 "pack_report: getpagesize() = %10" SZ_FMT "\n"
52 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
53 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
54 sz_fmt(getpagesize()),
55 sz_fmt(packed_git_window_size),
56 sz_fmt(packed_git_limit));
57 fprintf(stderr,
58 "pack_report: pack_used_ctr = %10u\n"
59 "pack_report: pack_mmap_calls = %10u\n"
60 "pack_report: pack_open_windows = %10u / %10u\n"
61 "pack_report: pack_mapped = "
62 "%10" SZ_FMT " / %10" SZ_FMT "\n",
63 pack_used_ctr,
64 pack_mmap_calls,
65 pack_open_windows, peak_pack_open_windows,
66 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
67}
0317f455
JT
68
69/*
70 * Open and mmap the index file at path, perform a couple of
71 * consistency checks, then record its information to p. Return 0 on
72 * success.
73 */
74static int check_packed_git_idx(const char *path, struct packed_git *p)
75{
76 void *idx_map;
77 struct pack_idx_header *hdr;
78 size_t idx_size;
79 uint32_t version, nr, i, *index;
80 int fd = git_open(path);
81 struct stat st;
82
83 if (fd < 0)
84 return -1;
85 if (fstat(fd, &st)) {
86 close(fd);
87 return -1;
88 }
89 idx_size = xsize_t(st.st_size);
90 if (idx_size < 4 * 256 + 20 + 20) {
91 close(fd);
92 return error("index file %s is too small", path);
93 }
94 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
95 close(fd);
96
97 hdr = idx_map;
98 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
99 version = ntohl(hdr->idx_version);
100 if (version < 2 || version > 2) {
101 munmap(idx_map, idx_size);
102 return error("index file %s is version %"PRIu32
103 " and is not supported by this binary"
104 " (try upgrading GIT to a newer version)",
105 path, version);
106 }
107 } else
108 version = 1;
109
110 nr = 0;
111 index = idx_map;
112 if (version > 1)
113 index += 2; /* skip index header */
114 for (i = 0; i < 256; i++) {
115 uint32_t n = ntohl(index[i]);
116 if (n < nr) {
117 munmap(idx_map, idx_size);
118 return error("non-monotonic index %s", path);
119 }
120 nr = n;
121 }
122
123 if (version == 1) {
124 /*
125 * Total size:
126 * - 256 index entries 4 bytes each
127 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
128 * - 20-byte SHA1 of the packfile
129 * - 20-byte SHA1 file checksum
130 */
131 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
132 munmap(idx_map, idx_size);
133 return error("wrong index v1 file size in %s", path);
134 }
135 } else if (version == 2) {
136 /*
137 * Minimum size:
138 * - 8 bytes of header
139 * - 256 index entries 4 bytes each
140 * - 20-byte sha1 entry * nr
141 * - 4-byte crc entry * nr
142 * - 4-byte offset entry * nr
143 * - 20-byte SHA1 of the packfile
144 * - 20-byte SHA1 file checksum
145 * And after the 4-byte offset table might be a
146 * variable sized table containing 8-byte entries
147 * for offsets larger than 2^31.
148 */
149 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
150 unsigned long max_size = min_size;
151 if (nr)
152 max_size += (nr - 1)*8;
153 if (idx_size < min_size || idx_size > max_size) {
154 munmap(idx_map, idx_size);
155 return error("wrong index v2 file size in %s", path);
156 }
157 if (idx_size != min_size &&
158 /*
159 * make sure we can deal with large pack offsets.
160 * 31-bit signed offset won't be enough, neither
161 * 32-bit unsigned one will be.
162 */
163 (sizeof(off_t) <= 4)) {
164 munmap(idx_map, idx_size);
165 return error("pack too large for current definition of off_t in %s", path);
166 }
167 }
168
169 p->index_version = version;
170 p->index_data = idx_map;
171 p->index_size = idx_size;
172 p->num_objects = nr;
173 return 0;
174}
175
176int open_pack_index(struct packed_git *p)
177{
178 char *idx_name;
179 size_t len;
180 int ret;
181
182 if (p->index_data)
183 return 0;
184
185 if (!strip_suffix(p->pack_name, ".pack", &len))
186 die("BUG: pack_name does not end in .pack");
187 idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
188 ret = check_packed_git_idx(idx_name, p);
189 free(idx_name);
190 return ret;
191}
192
193static struct packed_git *alloc_packed_git(int extra)
194{
195 struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
196 memset(p, 0, sizeof(*p));
197 p->pack_fd = -1;
198 return p;
199}
200
201struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
202{
203 const char *path = sha1_pack_name(sha1);
204 size_t alloc = st_add(strlen(path), 1);
205 struct packed_git *p = alloc_packed_git(alloc);
206
207 memcpy(p->pack_name, path, alloc); /* includes NUL */
208 hashcpy(p->sha1, sha1);
209 if (check_packed_git_idx(idx_path, p)) {
210 free(p);
211 return NULL;
212 }
213
214 return p;
215}
f0e17e86
JT
216
217static void scan_windows(struct packed_git *p,
218 struct packed_git **lru_p,
219 struct pack_window **lru_w,
220 struct pack_window **lru_l)
221{
222 struct pack_window *w, *w_l;
223
224 for (w_l = NULL, w = p->windows; w; w = w->next) {
225 if (!w->inuse_cnt) {
226 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
227 *lru_p = p;
228 *lru_w = w;
229 *lru_l = w_l;
230 }
231 }
232 w_l = w;
233 }
234}
235
84f80ad5 236static int unuse_one_window(struct packed_git *current)
f0e17e86
JT
237{
238 struct packed_git *p, *lru_p = NULL;
239 struct pack_window *lru_w = NULL, *lru_l = NULL;
240
241 if (current)
242 scan_windows(current, &lru_p, &lru_w, &lru_l);
243 for (p = packed_git; p; p = p->next)
244 scan_windows(p, &lru_p, &lru_w, &lru_l);
245 if (lru_p) {
246 munmap(lru_w->base, lru_w->len);
247 pack_mapped -= lru_w->len;
248 if (lru_l)
249 lru_l->next = lru_w->next;
250 else
251 lru_p->windows = lru_w->next;
252 free(lru_w);
253 pack_open_windows--;
254 return 1;
255 }
256 return 0;
257}
258
259void release_pack_memory(size_t need)
260{
261 size_t cur = pack_mapped;
262 while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
263 ; /* nothing */
264}
3836d88a
JT
265
266void close_pack_windows(struct packed_git *p)
267{
268 while (p->windows) {
269 struct pack_window *w = p->windows;
270
271 if (w->inuse_cnt)
272 die("pack '%s' still has open windows to it",
273 p->pack_name);
274 munmap(w->base, w->len);
275 pack_mapped -= w->len;
276 pack_open_windows--;
277 p->windows = w->next;
278 free(w);
279 }
280}
281
84f80ad5 282static int close_pack_fd(struct packed_git *p)
3836d88a
JT
283{
284 if (p->pack_fd < 0)
285 return 0;
286
287 close(p->pack_fd);
288 pack_open_fds--;
289 p->pack_fd = -1;
290
291 return 1;
292}
293
294void close_pack_index(struct packed_git *p)
295{
296 if (p->index_data) {
297 munmap((void *)p->index_data, p->index_size);
298 p->index_data = NULL;
299 }
300}
301
302static void close_pack(struct packed_git *p)
303{
304 close_pack_windows(p);
305 close_pack_fd(p);
306 close_pack_index(p);
307}
308
309void close_all_packs(void)
310{
311 struct packed_git *p;
312
313 for (p = packed_git; p; p = p->next)
314 if (p->do_not_close)
315 die("BUG: want to close pack marked 'do-not-close'");
316 else
317 close_pack(p);
318}
84f80ad5
JT
319
320/*
321 * The LRU pack is the one with the oldest MRU window, preferring packs
322 * with no used windows, or the oldest mtime if it has no windows allocated.
323 */
324static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
325{
326 struct pack_window *w, *this_mru_w;
327 int has_windows_inuse = 0;
328
329 /*
330 * Reject this pack if it has windows and the previously selected
331 * one does not. If this pack does not have windows, reject
332 * it if the pack file is newer than the previously selected one.
333 */
334 if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
335 return;
336
337 for (w = this_mru_w = p->windows; w; w = w->next) {
338 /*
339 * Reject this pack if any of its windows are in use,
340 * but the previously selected pack did not have any
341 * inuse windows. Otherwise, record that this pack
342 * has windows in use.
343 */
344 if (w->inuse_cnt) {
345 if (*accept_windows_inuse)
346 has_windows_inuse = 1;
347 else
348 return;
349 }
350
351 if (w->last_used > this_mru_w->last_used)
352 this_mru_w = w;
353
354 /*
355 * Reject this pack if it has windows that have been
356 * used more recently than the previously selected pack.
357 * If the previously selected pack had windows inuse and
358 * we have not encountered a window in this pack that is
359 * inuse, skip this check since we prefer a pack with no
360 * inuse windows to one that has inuse windows.
361 */
362 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
363 this_mru_w->last_used > (*mru_w)->last_used)
364 return;
365 }
366
367 /*
368 * Select this pack.
369 */
370 *mru_w = this_mru_w;
371 *lru_p = p;
372 *accept_windows_inuse = has_windows_inuse;
373}
374
375static int close_one_pack(void)
376{
377 struct packed_git *p, *lru_p = NULL;
378 struct pack_window *mru_w = NULL;
379 int accept_windows_inuse = 1;
380
381 for (p = packed_git; p; p = p->next) {
382 if (p->pack_fd == -1)
383 continue;
384 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
385 }
386
387 if (lru_p)
388 return close_pack_fd(lru_p);
389
390 return 0;
391}
392
393static unsigned int get_max_fd_limit(void)
394{
395#ifdef RLIMIT_NOFILE
396 {
397 struct rlimit lim;
398
399 if (!getrlimit(RLIMIT_NOFILE, &lim))
400 return lim.rlim_cur;
401 }
402#endif
403
404#ifdef _SC_OPEN_MAX
405 {
406 long open_max = sysconf(_SC_OPEN_MAX);
407 if (0 < open_max)
408 return open_max;
409 /*
410 * Otherwise, we got -1 for one of the two
411 * reasons:
412 *
413 * (1) sysconf() did not understand _SC_OPEN_MAX
414 * and signaled an error with -1; or
415 * (2) sysconf() said there is no limit.
416 *
417 * We _could_ clear errno before calling sysconf() to
418 * tell these two cases apart and return a huge number
419 * in the latter case to let the caller cap it to a
420 * value that is not so selfish, but letting the
421 * fallback OPEN_MAX codepath take care of these cases
422 * is a lot simpler.
423 */
424 }
425#endif
426
427#ifdef OPEN_MAX
428 return OPEN_MAX;
429#else
430 return 1; /* see the caller ;-) */
431#endif
432}
433
434/*
435 * Do not call this directly as this leaks p->pack_fd on error return;
436 * call open_packed_git() instead.
437 */
438static int open_packed_git_1(struct packed_git *p)
439{
440 struct stat st;
441 struct pack_header hdr;
442 unsigned char sha1[20];
443 unsigned char *idx_sha1;
444 long fd_flag;
41dcc4dc 445 ssize_t read_result;
84f80ad5
JT
446
447 if (!p->index_data && open_pack_index(p))
448 return error("packfile %s index unavailable", p->pack_name);
449
450 if (!pack_max_fds) {
451 unsigned int max_fds = get_max_fd_limit();
452
453 /* Save 3 for stdin/stdout/stderr, 22 for work */
454 if (25 < max_fds)
455 pack_max_fds = max_fds - 25;
456 else
457 pack_max_fds = 1;
458 }
459
460 while (pack_max_fds <= pack_open_fds && close_one_pack())
461 ; /* nothing */
462
463 p->pack_fd = git_open(p->pack_name);
464 if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
465 return -1;
466 pack_open_fds++;
467
468 /* If we created the struct before we had the pack we lack size. */
469 if (!p->pack_size) {
470 if (!S_ISREG(st.st_mode))
471 return error("packfile %s not a regular file", p->pack_name);
472 p->pack_size = st.st_size;
473 } else if (p->pack_size != st.st_size)
474 return error("packfile %s size changed", p->pack_name);
475
476 /* We leave these file descriptors open with sliding mmap;
477 * there is no point keeping them open across exec(), though.
478 */
479 fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
480 if (fd_flag < 0)
481 return error("cannot determine file descriptor flags");
482 fd_flag |= FD_CLOEXEC;
483 if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
484 return error("cannot set FD_CLOEXEC");
485
486 /* Verify we recognize this pack file format. */
41dcc4dc
JK
487 read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
488 if (read_result < 0)
489 return error_errno("error reading from %s", p->pack_name);
490 if (read_result != sizeof(hdr))
84f80ad5
JT
491 return error("file %s is far too short to be a packfile", p->pack_name);
492 if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
493 return error("file %s is not a GIT packfile", p->pack_name);
494 if (!pack_version_ok(hdr.hdr_version))
495 return error("packfile %s is version %"PRIu32" and not"
496 " supported (try upgrading GIT to a newer version)",
497 p->pack_name, ntohl(hdr.hdr_version));
498
499 /* Verify the pack matches its index. */
500 if (p->num_objects != ntohl(hdr.hdr_entries))
501 return error("packfile %s claims to have %"PRIu32" objects"
502 " while index indicates %"PRIu32" objects",
503 p->pack_name, ntohl(hdr.hdr_entries),
504 p->num_objects);
505 if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
506 return error("end of packfile %s is unavailable", p->pack_name);
41dcc4dc
JK
507 read_result = read_in_full(p->pack_fd, sha1, sizeof(sha1));
508 if (read_result < 0)
509 return error_errno("error reading from %s", p->pack_name);
510 if (read_result != sizeof(sha1))
84f80ad5
JT
511 return error("packfile %s signature is unavailable", p->pack_name);
512 idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
513 if (hashcmp(sha1, idx_sha1))
514 return error("packfile %s does not match index", p->pack_name);
515 return 0;
516}
517
a2551953 518static int open_packed_git(struct packed_git *p)
84f80ad5
JT
519{
520 if (!open_packed_git_1(p))
521 return 0;
522 close_pack_fd(p);
523 return -1;
524}
525
526static int in_window(struct pack_window *win, off_t offset)
527{
528 /* We must promise at least 20 bytes (one hash) after the
529 * offset is available from this window, otherwise the offset
530 * is not actually in this window and a different window (which
531 * has that one hash excess) must be used. This is to support
532 * the object header and delta base parsing routines below.
533 */
534 off_t win_off = win->offset;
535 return win_off <= offset
536 && (offset + 20) <= (win_off + win->len);
537}
538
539unsigned char *use_pack(struct packed_git *p,
540 struct pack_window **w_cursor,
541 off_t offset,
542 unsigned long *left)
543{
544 struct pack_window *win = *w_cursor;
545
546 /* Since packfiles end in a hash of their content and it's
547 * pointless to ask for an offset into the middle of that
548 * hash, and the in_window function above wouldn't match
549 * don't allow an offset too close to the end of the file.
550 */
551 if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
552 die("packfile %s cannot be accessed", p->pack_name);
553 if (offset > (p->pack_size - 20))
554 die("offset beyond end of packfile (truncated pack?)");
555 if (offset < 0)
556 die(_("offset before end of packfile (broken .idx?)"));
557
558 if (!win || !in_window(win, offset)) {
559 if (win)
560 win->inuse_cnt--;
561 for (win = p->windows; win; win = win->next) {
562 if (in_window(win, offset))
563 break;
564 }
565 if (!win) {
566 size_t window_align = packed_git_window_size / 2;
567 off_t len;
568
569 if (p->pack_fd == -1 && open_packed_git(p))
570 die("packfile %s cannot be accessed", p->pack_name);
571
572 win = xcalloc(1, sizeof(*win));
573 win->offset = (offset / window_align) * window_align;
574 len = p->pack_size - win->offset;
575 if (len > packed_git_window_size)
576 len = packed_git_window_size;
577 win->len = (size_t)len;
578 pack_mapped += win->len;
579 while (packed_git_limit < pack_mapped
580 && unuse_one_window(p))
581 ; /* nothing */
582 win->base = xmmap(NULL, win->len,
583 PROT_READ, MAP_PRIVATE,
584 p->pack_fd, win->offset);
585 if (win->base == MAP_FAILED)
586 die_errno("packfile %s cannot be mapped",
587 p->pack_name);
588 if (!win->offset && win->len == p->pack_size
589 && !p->do_not_close)
590 close_pack_fd(p);
591 pack_mmap_calls++;
592 pack_open_windows++;
593 if (pack_mapped > peak_pack_mapped)
594 peak_pack_mapped = pack_mapped;
595 if (pack_open_windows > peak_pack_open_windows)
596 peak_pack_open_windows = pack_open_windows;
597 win->next = p->windows;
598 p->windows = win;
599 }
600 }
601 if (win != *w_cursor) {
602 win->last_used = pack_used_ctr++;
603 win->inuse_cnt++;
604 *w_cursor = win;
605 }
606 offset -= win->offset;
607 if (left)
608 *left = win->len - xsize_t(offset);
609 return win->base + offset;
610}
97de1803
JT
611
612void unuse_pack(struct pack_window **w_cursor)
613{
614 struct pack_window *w = *w_cursor;
615 if (w) {
616 w->inuse_cnt--;
617 *w_cursor = NULL;
618 }
619}
9a428653
JT
620
621static void try_to_free_pack_memory(size_t size)
622{
623 release_pack_memory(size);
624}
625
626struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
627{
628 static int have_set_try_to_free_routine;
629 struct stat st;
630 size_t alloc;
631 struct packed_git *p;
632
633 if (!have_set_try_to_free_routine) {
634 have_set_try_to_free_routine = 1;
635 set_try_to_free_routine(try_to_free_pack_memory);
636 }
637
638 /*
639 * Make sure a corresponding .pack file exists and that
640 * the index looks sane.
641 */
642 if (!strip_suffix_mem(path, &path_len, ".idx"))
643 return NULL;
644
645 /*
646 * ".pack" is long enough to hold any suffix we're adding (and
647 * the use xsnprintf double-checks that)
648 */
649 alloc = st_add3(path_len, strlen(".pack"), 1);
650 p = alloc_packed_git(alloc);
651 memcpy(p->pack_name, path, path_len);
652
653 xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
654 if (!access(p->pack_name, F_OK))
655 p->pack_keep = 1;
656
657 xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
658 if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
659 free(p);
660 return NULL;
661 }
662
663 /* ok, it looks sane as far as we can check without
664 * actually mapping the pack file.
665 */
666 p->pack_size = st.st_size;
667 p->pack_local = local;
668 p->mtime = st.st_mtime;
669 if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
670 hashclr(p->sha1);
671 return p;
672}
e65f1862
JT
673
674void install_packed_git(struct packed_git *pack)
675{
676 if (pack->pack_fd != -1)
677 pack_open_fds++;
678
679 pack->next = packed_git;
680 packed_git = pack;
681}
0abe14f6
JT
682
683void (*report_garbage)(unsigned seen_bits, const char *path);
684
685static void report_helper(const struct string_list *list,
686 int seen_bits, int first, int last)
687{
688 if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
689 return;
690
691 for (; first < last; first++)
692 report_garbage(seen_bits, list->items[first].string);
693}
694
695static void report_pack_garbage(struct string_list *list)
696{
697 int i, baselen = -1, first = 0, seen_bits = 0;
698
699 if (!report_garbage)
700 return;
701
702 string_list_sort(list);
703
704 for (i = 0; i < list->nr; i++) {
705 const char *path = list->items[i].string;
706 if (baselen != -1 &&
707 strncmp(path, list->items[first].string, baselen)) {
708 report_helper(list, seen_bits, first, i);
709 baselen = -1;
710 seen_bits = 0;
711 }
712 if (baselen == -1) {
713 const char *dot = strrchr(path, '.');
714 if (!dot) {
715 report_garbage(PACKDIR_FILE_GARBAGE, path);
716 continue;
717 }
718 baselen = dot - path + 1;
719 first = i;
720 }
721 if (!strcmp(path + baselen, "pack"))
722 seen_bits |= 1;
723 else if (!strcmp(path + baselen, "idx"))
724 seen_bits |= 2;
725 }
726 report_helper(list, seen_bits, first, list->nr);
727}
728
729static void prepare_packed_git_one(char *objdir, int local)
730{
731 struct strbuf path = STRBUF_INIT;
732 size_t dirnamelen;
733 DIR *dir;
734 struct dirent *de;
735 struct string_list garbage = STRING_LIST_INIT_DUP;
736
737 strbuf_addstr(&path, objdir);
738 strbuf_addstr(&path, "/pack");
739 dir = opendir(path.buf);
740 if (!dir) {
741 if (errno != ENOENT)
742 error_errno("unable to open object pack directory: %s",
743 path.buf);
744 strbuf_release(&path);
745 return;
746 }
747 strbuf_addch(&path, '/');
748 dirnamelen = path.len;
749 while ((de = readdir(dir)) != NULL) {
750 struct packed_git *p;
751 size_t base_len;
752
753 if (is_dot_or_dotdot(de->d_name))
754 continue;
755
756 strbuf_setlen(&path, dirnamelen);
757 strbuf_addstr(&path, de->d_name);
758
759 base_len = path.len;
760 if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
761 /* Don't reopen a pack we already have. */
762 for (p = packed_git; p; p = p->next) {
763 size_t len;
764 if (strip_suffix(p->pack_name, ".pack", &len) &&
765 len == base_len &&
766 !memcmp(p->pack_name, path.buf, len))
767 break;
768 }
769 if (p == NULL &&
770 /*
771 * See if it really is a valid .idx file with
772 * corresponding .pack file that we can map.
773 */
774 (p = add_packed_git(path.buf, path.len, local)) != NULL)
775 install_packed_git(p);
776 }
777
778 if (!report_garbage)
779 continue;
780
781 if (ends_with(de->d_name, ".idx") ||
782 ends_with(de->d_name, ".pack") ||
783 ends_with(de->d_name, ".bitmap") ||
784 ends_with(de->d_name, ".keep"))
785 string_list_append(&garbage, path.buf);
786 else
787 report_garbage(PACKDIR_FILE_GARBAGE, path.buf);
788 }
789 closedir(dir);
790 report_pack_garbage(&garbage);
791 string_list_clear(&garbage, 0);
792 strbuf_release(&path);
793}
794
795static int approximate_object_count_valid;
796
797/*
798 * Give a fast, rough count of the number of objects in the repository. This
799 * ignores loose objects completely. If you have a lot of them, then either
800 * you should repack because your performance will be awful, or they are
801 * all unreachable objects about to be pruned, in which case they're not really
802 * interesting as a measure of repo size in the first place.
803 */
804unsigned long approximate_object_count(void)
805{
806 static unsigned long count;
807 if (!approximate_object_count_valid) {
808 struct packed_git *p;
809
810 prepare_packed_git();
811 count = 0;
812 for (p = packed_git; p; p = p->next) {
813 if (open_pack_index(p))
814 continue;
815 count += p->num_objects;
816 }
817 }
818 return count;
819}
820
821static void *get_next_packed_git(const void *p)
822{
823 return ((const struct packed_git *)p)->next;
824}
825
826static void set_next_packed_git(void *p, void *next)
827{
828 ((struct packed_git *)p)->next = next;
829}
830
831static int sort_pack(const void *a_, const void *b_)
832{
833 const struct packed_git *a = a_;
834 const struct packed_git *b = b_;
835 int st;
836
837 /*
838 * Local packs tend to contain objects specific to our
839 * variant of the project than remote ones. In addition,
840 * remote ones could be on a network mounted filesystem.
841 * Favor local ones for these reasons.
842 */
843 st = a->pack_local - b->pack_local;
844 if (st)
845 return -st;
846
847 /*
848 * Younger packs tend to contain more recent objects,
849 * and more recent objects tend to get accessed more
850 * often.
851 */
852 if (a->mtime < b->mtime)
853 return 1;
854 else if (a->mtime == b->mtime)
855 return 0;
856 return -1;
857}
858
859static void rearrange_packed_git(void)
860{
861 packed_git = llist_mergesort(packed_git, get_next_packed_git,
862 set_next_packed_git, sort_pack);
863}
864
865static void prepare_packed_git_mru(void)
866{
867 struct packed_git *p;
868
607bd831 869 mru_clear(&packed_git_mru);
0abe14f6 870 for (p = packed_git; p; p = p->next)
607bd831 871 mru_append(&packed_git_mru, p);
0abe14f6
JT
872}
873
874static int prepare_packed_git_run_once = 0;
875void prepare_packed_git(void)
876{
877 struct alternate_object_database *alt;
878
879 if (prepare_packed_git_run_once)
880 return;
881 prepare_packed_git_one(get_object_directory(), 1);
882 prepare_alt_odb();
883 for (alt = alt_odb_list; alt; alt = alt->next)
884 prepare_packed_git_one(alt->path, 0);
885 rearrange_packed_git();
886 prepare_packed_git_mru();
887 prepare_packed_git_run_once = 1;
888}
889
890void reprepare_packed_git(void)
891{
892 approximate_object_count_valid = 0;
893 prepare_packed_git_run_once = 0;
894 prepare_packed_git();
895}
32b42e15
JT
896
897unsigned long unpack_object_header_buffer(const unsigned char *buf,
898 unsigned long len, enum object_type *type, unsigned long *sizep)
899{
900 unsigned shift;
901 unsigned long size, c;
902 unsigned long used = 0;
903
904 c = buf[used++];
905 *type = (c >> 4) & 7;
906 size = c & 15;
907 shift = 4;
908 while (c & 0x80) {
909 if (len <= used || bitsizeof(long) <= shift) {
910 error("bad object header");
911 size = used = 0;
912 break;
913 }
914 c = buf[used++];
915 size += (c & 0x7f) << shift;
916 shift += 7;
917 }
918 *sizep = size;
919 return used;
920}
7b3aa75d
JT
921
922unsigned long get_size_from_delta(struct packed_git *p,
923 struct pack_window **w_curs,
924 off_t curpos)
925{
926 const unsigned char *data;
927 unsigned char delta_head[20], *in;
928 git_zstream stream;
929 int st;
930
931 memset(&stream, 0, sizeof(stream));
932 stream.next_out = delta_head;
933 stream.avail_out = sizeof(delta_head);
934
935 git_inflate_init(&stream);
936 do {
937 in = use_pack(p, w_curs, curpos, &stream.avail_in);
938 stream.next_in = in;
939 st = git_inflate(&stream, Z_FINISH);
940 curpos += stream.next_in - in;
941 } while ((st == Z_OK || st == Z_BUF_ERROR) &&
942 stream.total_out < sizeof(delta_head));
943 git_inflate_end(&stream);
944 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
945 error("delta data unpack-initial failed");
946 return 0;
947 }
948
949 /* Examine the initial part of the delta to figure out
950 * the result size.
951 */
952 data = delta_head;
953
954 /* ignore base size */
955 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
956
957 /* Read the result size */
958 return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
959}
3588dd6e
JT
960
961int unpack_object_header(struct packed_git *p,
962 struct pack_window **w_curs,
963 off_t *curpos,
964 unsigned long *sizep)
965{
966 unsigned char *base;
967 unsigned long left;
968 unsigned long used;
969 enum object_type type;
970
971 /* use_pack() assures us we have [base, base + 20) available
972 * as a range that we can look at. (Its actually the hash
973 * size that is assured.) With our object header encoding
974 * the maximum deflated object size is 2^137, which is just
975 * insane, so we know won't exceed what we have been given.
976 */
977 base = use_pack(p, w_curs, *curpos, &left);
978 used = unpack_object_header_buffer(base, left, &type, sizep);
979 if (!used) {
980 type = OBJ_BAD;
981 } else
982 *curpos += used;
983
984 return type;
985}
f1d8130b
JT
986
987void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
988{
989 unsigned i;
990 for (i = 0; i < p->num_bad_objects; i++)
991 if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
992 return;
993 p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
994 st_mult(GIT_MAX_RAWSZ,
995 st_add(p->num_bad_objects, 1)));
996 hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
997 p->num_bad_objects++;
998}
999
1000const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1001{
1002 struct packed_git *p;
1003 unsigned i;
1004
1005 for (p = packed_git; p; p = p->next)
1006 for (i = 0; i < p->num_bad_objects; i++)
1007 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1008 return p;
1009 return NULL;
1010}
1011
1012static off_t get_delta_base(struct packed_git *p,
1013 struct pack_window **w_curs,
1014 off_t *curpos,
1015 enum object_type type,
1016 off_t delta_obj_offset)
1017{
1018 unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1019 off_t base_offset;
1020
1021 /* use_pack() assured us we have [base_info, base_info + 20)
1022 * as a range that we can look at without walking off the
1023 * end of the mapped window. Its actually the hash size
1024 * that is assured. An OFS_DELTA longer than the hash size
1025 * is stupid, as then a REF_DELTA would be smaller to store.
1026 */
1027 if (type == OBJ_OFS_DELTA) {
1028 unsigned used = 0;
1029 unsigned char c = base_info[used++];
1030 base_offset = c & 127;
1031 while (c & 128) {
1032 base_offset += 1;
1033 if (!base_offset || MSB(base_offset, 7))
1034 return 0; /* overflow */
1035 c = base_info[used++];
1036 base_offset = (base_offset << 7) + (c & 127);
1037 }
1038 base_offset = delta_obj_offset - base_offset;
1039 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1040 return 0; /* out of bound */
1041 *curpos += used;
1042 } else if (type == OBJ_REF_DELTA) {
1043 /* The base entry _must_ be in the same pack */
1044 base_offset = find_pack_entry_one(base_info, p);
1045 *curpos += 20;
1046 } else
1047 die("I am totally screwed");
1048 return base_offset;
1049}
1050
1051/*
1052 * Like get_delta_base above, but we return the sha1 instead of the pack
1053 * offset. This means it is cheaper for REF deltas (we do not have to do
1054 * the final object lookup), but more expensive for OFS deltas (we
1055 * have to load the revidx to convert the offset back into a sha1).
1056 */
1057static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1058 struct pack_window **w_curs,
1059 off_t curpos,
1060 enum object_type type,
1061 off_t delta_obj_offset)
1062{
1063 if (type == OBJ_REF_DELTA) {
1064 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1065 return base;
1066 } else if (type == OBJ_OFS_DELTA) {
1067 struct revindex_entry *revidx;
1068 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1069 type, delta_obj_offset);
1070
1071 if (!base_offset)
1072 return NULL;
1073
1074 revidx = find_pack_revindex(p, base_offset);
1075 if (!revidx)
1076 return NULL;
1077
1078 return nth_packed_object_sha1(p, revidx->nr);
1079 } else
1080 return NULL;
1081}
1082
1083static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
1084{
1085 int type;
1086 struct revindex_entry *revidx;
1087 const unsigned char *sha1;
1088 revidx = find_pack_revindex(p, obj_offset);
1089 if (!revidx)
1090 return OBJ_BAD;
1091 sha1 = nth_packed_object_sha1(p, revidx->nr);
1092 mark_bad_packed_object(p, sha1);
1093 type = sha1_object_info(sha1, NULL);
1094 if (type <= OBJ_NONE)
1095 return OBJ_BAD;
1096 return type;
1097}
1098
1099#define POI_STACK_PREALLOC 64
1100
1101static enum object_type packed_to_object_type(struct packed_git *p,
1102 off_t obj_offset,
1103 enum object_type type,
1104 struct pack_window **w_curs,
1105 off_t curpos)
1106{
1107 off_t small_poi_stack[POI_STACK_PREALLOC];
1108 off_t *poi_stack = small_poi_stack;
1109 int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1110
1111 while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1112 off_t base_offset;
1113 unsigned long size;
1114 /* Push the object we're going to leave behind */
1115 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1116 poi_stack_alloc = alloc_nr(poi_stack_nr);
1117 ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1118 memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1119 } else {
1120 ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1121 }
1122 poi_stack[poi_stack_nr++] = obj_offset;
1123 /* If parsing the base offset fails, just unwind */
1124 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1125 if (!base_offset)
1126 goto unwind;
1127 curpos = obj_offset = base_offset;
1128 type = unpack_object_header(p, w_curs, &curpos, &size);
1129 if (type <= OBJ_NONE) {
1130 /* If getting the base itself fails, we first
1131 * retry the base, otherwise unwind */
1132 type = retry_bad_packed_offset(p, base_offset);
1133 if (type > OBJ_NONE)
1134 goto out;
1135 goto unwind;
1136 }
1137 }
1138
1139 switch (type) {
1140 case OBJ_BAD:
1141 case OBJ_COMMIT:
1142 case OBJ_TREE:
1143 case OBJ_BLOB:
1144 case OBJ_TAG:
1145 break;
1146 default:
1147 error("unknown object type %i at offset %"PRIuMAX" in %s",
1148 type, (uintmax_t)obj_offset, p->pack_name);
1149 type = OBJ_BAD;
1150 }
1151
1152out:
1153 if (poi_stack != small_poi_stack)
1154 free(poi_stack);
1155 return type;
1156
1157unwind:
1158 while (poi_stack_nr) {
1159 obj_offset = poi_stack[--poi_stack_nr];
1160 type = retry_bad_packed_offset(p, obj_offset);
1161 if (type > OBJ_NONE)
1162 goto out;
1163 }
1164 type = OBJ_BAD;
1165 goto out;
1166}
1167
1168static struct hashmap delta_base_cache;
1169static size_t delta_base_cached;
1170
1171static LIST_HEAD(delta_base_cache_lru);
1172
1173struct delta_base_cache_key {
1174 struct packed_git *p;
1175 off_t base_offset;
1176};
1177
1178struct delta_base_cache_entry {
1179 struct hashmap hash;
1180 struct delta_base_cache_key key;
1181 struct list_head lru;
1182 void *data;
1183 unsigned long size;
1184 enum object_type type;
1185};
1186
1187static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1188{
1189 unsigned int hash;
1190
1191 hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1192 hash += (hash >> 8) + (hash >> 16);
1193 return hash;
1194}
1195
1196static struct delta_base_cache_entry *
1197get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1198{
1199 struct hashmap_entry entry;
1200 struct delta_base_cache_key key;
1201
1202 if (!delta_base_cache.cmpfn)
1203 return NULL;
1204
1205 hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1206 key.p = p;
1207 key.base_offset = base_offset;
1208 return hashmap_get(&delta_base_cache, &entry, &key);
1209}
1210
1211static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
1212 const struct delta_base_cache_key *b)
1213{
1214 return a->p == b->p && a->base_offset == b->base_offset;
1215}
1216
1217static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
1218 const void *va, const void *vb,
1219 const void *vkey)
1220{
1221 const struct delta_base_cache_entry *a = va, *b = vb;
1222 const struct delta_base_cache_key *key = vkey;
1223 if (key)
1224 return !delta_base_cache_key_eq(&a->key, key);
1225 else
1226 return !delta_base_cache_key_eq(&a->key, &b->key);
1227}
1228
1229static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1230{
1231 return !!get_delta_base_cache_entry(p, base_offset);
1232}
1233
1234/*
1235 * Remove the entry from the cache, but do _not_ free the associated
1236 * entry data. The caller takes ownership of the "data" buffer, and
1237 * should copy out any fields it wants before detaching.
1238 */
1239static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1240{
1241 hashmap_remove(&delta_base_cache, ent, &ent->key);
1242 list_del(&ent->lru);
1243 delta_base_cached -= ent->size;
1244 free(ent);
1245}
1246
1247static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1248 unsigned long *base_size, enum object_type *type)
1249{
1250 struct delta_base_cache_entry *ent;
1251
1252 ent = get_delta_base_cache_entry(p, base_offset);
1253 if (!ent)
1254 return unpack_entry(p, base_offset, type, base_size);
1255
1256 if (type)
1257 *type = ent->type;
1258 if (base_size)
1259 *base_size = ent->size;
1260 return xmemdupz(ent->data, ent->size);
1261}
1262
1263static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1264{
1265 free(ent->data);
1266 detach_delta_base_cache_entry(ent);
1267}
1268
1269void clear_delta_base_cache(void)
1270{
1271 struct list_head *lru, *tmp;
1272 list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1273 struct delta_base_cache_entry *entry =
1274 list_entry(lru, struct delta_base_cache_entry, lru);
1275 release_delta_base_cache(entry);
1276 }
1277}
1278
1279static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1280 void *base, unsigned long base_size, enum object_type type)
1281{
1282 struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1283 struct list_head *lru, *tmp;
1284
1285 delta_base_cached += base_size;
1286
1287 list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1288 struct delta_base_cache_entry *f =
1289 list_entry(lru, struct delta_base_cache_entry, lru);
1290 if (delta_base_cached <= delta_base_cache_limit)
1291 break;
1292 release_delta_base_cache(f);
1293 }
1294
1295 ent->key.p = p;
1296 ent->key.base_offset = base_offset;
1297 ent->type = type;
1298 ent->data = base;
1299 ent->size = base_size;
1300 list_add_tail(&ent->lru, &delta_base_cache_lru);
1301
1302 if (!delta_base_cache.cmpfn)
1303 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1304 hashmap_entry_init(ent, pack_entry_hash(p, base_offset));
1305 hashmap_add(&delta_base_cache, ent);
1306}
1307
1308int packed_object_info(struct packed_git *p, off_t obj_offset,
1309 struct object_info *oi)
1310{
1311 struct pack_window *w_curs = NULL;
1312 unsigned long size;
1313 off_t curpos = obj_offset;
1314 enum object_type type;
1315
1316 /*
1317 * We always get the representation type, but only convert it to
1318 * a "real" type later if the caller is interested.
1319 */
1320 if (oi->contentp) {
1321 *oi->contentp = cache_or_unpack_entry(p, obj_offset, oi->sizep,
1322 &type);
1323 if (!*oi->contentp)
1324 type = OBJ_BAD;
1325 } else {
1326 type = unpack_object_header(p, &w_curs, &curpos, &size);
1327 }
1328
1329 if (!oi->contentp && oi->sizep) {
1330 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1331 off_t tmp_pos = curpos;
1332 off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1333 type, obj_offset);
1334 if (!base_offset) {
1335 type = OBJ_BAD;
1336 goto out;
1337 }
1338 *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1339 if (*oi->sizep == 0) {
1340 type = OBJ_BAD;
1341 goto out;
1342 }
1343 } else {
1344 *oi->sizep = size;
1345 }
1346 }
1347
1348 if (oi->disk_sizep) {
1349 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1350 *oi->disk_sizep = revidx[1].offset - obj_offset;
1351 }
1352
1353 if (oi->typep || oi->typename) {
1354 enum object_type ptot;
1355 ptot = packed_to_object_type(p, obj_offset, type, &w_curs,
1356 curpos);
1357 if (oi->typep)
1358 *oi->typep = ptot;
1359 if (oi->typename) {
1360 const char *tn = typename(ptot);
1361 if (tn)
1362 strbuf_addstr(oi->typename, tn);
1363 }
1364 if (ptot < 0) {
1365 type = OBJ_BAD;
1366 goto out;
1367 }
1368 }
1369
1370 if (oi->delta_base_sha1) {
1371 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1372 const unsigned char *base;
1373
1374 base = get_delta_base_sha1(p, &w_curs, curpos,
1375 type, obj_offset);
1376 if (!base) {
1377 type = OBJ_BAD;
1378 goto out;
1379 }
1380
1381 hashcpy(oi->delta_base_sha1, base);
1382 } else
1383 hashclr(oi->delta_base_sha1);
1384 }
1385
1386 oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1387 OI_PACKED;
1388
1389out:
1390 unuse_pack(&w_curs);
1391 return type;
1392}
1393
1394static void *unpack_compressed_entry(struct packed_git *p,
1395 struct pack_window **w_curs,
1396 off_t curpos,
1397 unsigned long size)
1398{
1399 int st;
1400 git_zstream stream;
1401 unsigned char *buffer, *in;
1402
1403 buffer = xmallocz_gently(size);
1404 if (!buffer)
1405 return NULL;
1406 memset(&stream, 0, sizeof(stream));
1407 stream.next_out = buffer;
1408 stream.avail_out = size + 1;
1409
1410 git_inflate_init(&stream);
1411 do {
1412 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1413 stream.next_in = in;
1414 st = git_inflate(&stream, Z_FINISH);
1415 if (!stream.avail_out)
1416 break; /* the payload is larger than it should be */
1417 curpos += stream.next_in - in;
1418 } while (st == Z_OK || st == Z_BUF_ERROR);
1419 git_inflate_end(&stream);
1420 if ((st != Z_STREAM_END) || stream.total_out != size) {
1421 free(buffer);
1422 return NULL;
1423 }
1424
1425 return buffer;
1426}
1427
1428static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1429{
1430 static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1431 trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1432 p->pack_name, (uintmax_t)obj_offset);
1433}
1434
1435int do_check_packed_object_crc;
1436
1437#define UNPACK_ENTRY_STACK_PREALLOC 64
1438struct unpack_entry_stack_ent {
1439 off_t obj_offset;
1440 off_t curpos;
1441 unsigned long size;
1442};
1443
1444static void *read_object(const unsigned char *sha1, enum object_type *type,
1445 unsigned long *size)
1446{
1447 struct object_info oi = OBJECT_INFO_INIT;
1448 void *content;
1449 oi.typep = type;
1450 oi.sizep = size;
1451 oi.contentp = &content;
1452
1453 if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1454 return NULL;
1455 return content;
1456}
1457
1458void *unpack_entry(struct packed_git *p, off_t obj_offset,
1459 enum object_type *final_type, unsigned long *final_size)
1460{
1461 struct pack_window *w_curs = NULL;
1462 off_t curpos = obj_offset;
1463 void *data = NULL;
1464 unsigned long size;
1465 enum object_type type;
1466 struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1467 struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1468 int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1469 int base_from_cache = 0;
1470
1471 write_pack_access_log(p, obj_offset);
1472
1473 /* PHASE 1: drill down to the innermost base object */
1474 for (;;) {
1475 off_t base_offset;
1476 int i;
1477 struct delta_base_cache_entry *ent;
1478
1479 ent = get_delta_base_cache_entry(p, curpos);
1480 if (ent) {
1481 type = ent->type;
1482 data = ent->data;
1483 size = ent->size;
1484 detach_delta_base_cache_entry(ent);
1485 base_from_cache = 1;
1486 break;
1487 }
1488
1489 if (do_check_packed_object_crc && p->index_version > 1) {
1490 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1491 off_t len = revidx[1].offset - obj_offset;
1492 if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1493 const unsigned char *sha1 =
1494 nth_packed_object_sha1(p, revidx->nr);
1495 error("bad packed object CRC for %s",
1496 sha1_to_hex(sha1));
1497 mark_bad_packed_object(p, sha1);
1498 data = NULL;
1499 goto out;
1500 }
1501 }
1502
1503 type = unpack_object_header(p, &w_curs, &curpos, &size);
1504 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1505 break;
1506
1507 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1508 if (!base_offset) {
1509 error("failed to validate delta base reference "
1510 "at offset %"PRIuMAX" from %s",
1511 (uintmax_t)curpos, p->pack_name);
1512 /* bail to phase 2, in hopes of recovery */
1513 data = NULL;
1514 break;
1515 }
1516
1517 /* push object, proceed to base */
1518 if (delta_stack_nr >= delta_stack_alloc
1519 && delta_stack == small_delta_stack) {
1520 delta_stack_alloc = alloc_nr(delta_stack_nr);
1521 ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1522 memcpy(delta_stack, small_delta_stack,
1523 sizeof(*delta_stack)*delta_stack_nr);
1524 } else {
1525 ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1526 }
1527 i = delta_stack_nr++;
1528 delta_stack[i].obj_offset = obj_offset;
1529 delta_stack[i].curpos = curpos;
1530 delta_stack[i].size = size;
1531
1532 curpos = obj_offset = base_offset;
1533 }
1534
1535 /* PHASE 2: handle the base */
1536 switch (type) {
1537 case OBJ_OFS_DELTA:
1538 case OBJ_REF_DELTA:
1539 if (data)
1540 die("BUG: unpack_entry: left loop at a valid delta");
1541 break;
1542 case OBJ_COMMIT:
1543 case OBJ_TREE:
1544 case OBJ_BLOB:
1545 case OBJ_TAG:
1546 if (!base_from_cache)
1547 data = unpack_compressed_entry(p, &w_curs, curpos, size);
1548 break;
1549 default:
1550 data = NULL;
1551 error("unknown object type %i at offset %"PRIuMAX" in %s",
1552 type, (uintmax_t)obj_offset, p->pack_name);
1553 }
1554
1555 /* PHASE 3: apply deltas in order */
1556
1557 /* invariants:
1558 * 'data' holds the base data, or NULL if there was corruption
1559 */
1560 while (delta_stack_nr) {
1561 void *delta_data;
1562 void *base = data;
1563 void *external_base = NULL;
1564 unsigned long delta_size, base_size = size;
1565 int i;
1566
1567 data = NULL;
1568
1569 if (base)
1570 add_delta_base_cache(p, obj_offset, base, base_size, type);
1571
1572 if (!base) {
1573 /*
1574 * We're probably in deep shit, but let's try to fetch
1575 * the required base anyway from another pack or loose.
1576 * This is costly but should happen only in the presence
1577 * of a corrupted pack, and is better than failing outright.
1578 */
1579 struct revindex_entry *revidx;
1580 const unsigned char *base_sha1;
1581 revidx = find_pack_revindex(p, obj_offset);
1582 if (revidx) {
1583 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1584 error("failed to read delta base object %s"
1585 " at offset %"PRIuMAX" from %s",
1586 sha1_to_hex(base_sha1), (uintmax_t)obj_offset,
1587 p->pack_name);
1588 mark_bad_packed_object(p, base_sha1);
1589 base = read_object(base_sha1, &type, &base_size);
1590 external_base = base;
1591 }
1592 }
1593
1594 i = --delta_stack_nr;
1595 obj_offset = delta_stack[i].obj_offset;
1596 curpos = delta_stack[i].curpos;
1597 delta_size = delta_stack[i].size;
1598
1599 if (!base)
1600 continue;
1601
1602 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1603
1604 if (!delta_data) {
1605 error("failed to unpack compressed delta "
1606 "at offset %"PRIuMAX" from %s",
1607 (uintmax_t)curpos, p->pack_name);
1608 data = NULL;
1609 free(external_base);
1610 continue;
1611 }
1612
1613 data = patch_delta(base, base_size,
1614 delta_data, delta_size,
1615 &size);
1616
1617 /*
1618 * We could not apply the delta; warn the user, but keep going.
1619 * Our failure will be noticed either in the next iteration of
1620 * the loop, or if this is the final delta, in the caller when
1621 * we return NULL. Those code paths will take care of making
1622 * a more explicit warning and retrying with another copy of
1623 * the object.
1624 */
1625 if (!data)
1626 error("failed to apply delta");
1627
1628 free(delta_data);
1629 free(external_base);
1630 }
1631
1632 if (final_type)
1633 *final_type = type;
1634 if (final_size)
1635 *final_size = size;
1636
1637out:
1638 unuse_pack(&w_curs);
1639
1640 if (delta_stack != small_delta_stack)
1641 free(delta_stack);
1642
1643 return data;
1644}
d5a16761
JT
1645
1646const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1647 uint32_t n)
1648{
1649 const unsigned char *index = p->index_data;
1650 if (!index) {
1651 if (open_pack_index(p))
1652 return NULL;
1653 index = p->index_data;
1654 }
1655 if (n >= p->num_objects)
1656 return NULL;
1657 index += 4 * 256;
1658 if (p->index_version == 1) {
1659 return index + 24 * n + 4;
1660 } else {
1661 index += 8;
1662 return index + 20 * n;
1663 }
1664}
1665
1666const struct object_id *nth_packed_object_oid(struct object_id *oid,
1667 struct packed_git *p,
1668 uint32_t n)
1669{
1670 const unsigned char *hash = nth_packed_object_sha1(p, n);
1671 if (!hash)
1672 return NULL;
1673 hashcpy(oid->hash, hash);
1674 return oid;
1675}
9e0f45f5
JT
1676
1677void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1678{
1679 const unsigned char *ptr = vptr;
1680 const unsigned char *start = p->index_data;
1681 const unsigned char *end = start + p->index_size;
1682 if (ptr < start)
1683 die(_("offset before start of pack index for %s (corrupt index?)"),
1684 p->pack_name);
1685 /* No need to check for underflow; .idx files must be at least 8 bytes */
1686 if (ptr >= end - 8)
1687 die(_("offset beyond end of pack index for %s (truncated index?)"),
1688 p->pack_name);
1689}
1690
1691off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1692{
1693 const unsigned char *index = p->index_data;
1694 index += 4 * 256;
1695 if (p->index_version == 1) {
1696 return ntohl(*((uint32_t *)(index + 24 * n)));
1697 } else {
1698 uint32_t off;
1699 index += 8 + p->num_objects * (20 + 4);
1700 off = ntohl(*((uint32_t *)(index + 4 * n)));
1701 if (!(off & 0x80000000))
1702 return off;
1703 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1704 check_pack_index_ptr(p, index);
1705 return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
1706 ntohl(*((uint32_t *)(index + 4)));
1707 }
1708}
a2551953
JT
1709
1710off_t find_pack_entry_one(const unsigned char *sha1,
1711 struct packed_git *p)
1712{
1713 const uint32_t *level1_ofs = p->index_data;
1714 const unsigned char *index = p->index_data;
1715 unsigned hi, lo, stride;
1716 static int debug_lookup = -1;
1717
1718 if (debug_lookup < 0)
1719 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
1720
1721 if (!index) {
1722 if (open_pack_index(p))
1723 return 0;
1724 level1_ofs = p->index_data;
1725 index = p->index_data;
1726 }
1727 if (p->index_version > 1) {
1728 level1_ofs += 2;
1729 index += 8;
1730 }
1731 index += 4 * 256;
1732 hi = ntohl(level1_ofs[*sha1]);
1733 lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1734 if (p->index_version > 1) {
1735 stride = 20;
1736 } else {
1737 stride = 24;
1738 index += 4;
1739 }
1740
1741 if (debug_lookup)
1742 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
1743 sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
1744
1745 while (lo < hi) {
19716b21 1746 unsigned mi = lo + (hi - lo) / 2;
a2551953
JT
1747 int cmp = hashcmp(index + mi * stride, sha1);
1748
1749 if (debug_lookup)
1750 printf("lo %u hi %u rg %u mi %u\n",
1751 lo, hi, hi - lo, mi);
1752 if (!cmp)
1753 return nth_packed_object_offset(p, mi);
1754 if (cmp > 0)
1755 hi = mi;
1756 else
1757 lo = mi+1;
1758 }
1759 return 0;
1760}
1761
1762int is_pack_valid(struct packed_git *p)
1763{
1764 /* An already open pack is known to be valid. */
1765 if (p->pack_fd != -1)
1766 return 1;
1767
1768 /* If the pack has one window completely covering the
1769 * file size, the pack is known to be valid even if
1770 * the descriptor is not currently open.
1771 */
1772 if (p->windows) {
1773 struct pack_window *w = p->windows;
1774
1775 if (!w->offset && w->len == p->pack_size)
1776 return 1;
1777 }
1778
1779 /* Force the pack to open to prove its valid. */
1780 return !open_packed_git(p);
1781}
d6fe0036
JT
1782
1783struct packed_git *find_sha1_pack(const unsigned char *sha1,
1784 struct packed_git *packs)
1785{
1786 struct packed_git *p;
1787
1788 for (p = packs; p; p = p->next) {
1789 if (find_pack_entry_one(sha1, p))
1790 return p;
1791 }
1792 return NULL;
1793
1794}
1a1e5d4f
JT
1795
1796static int fill_pack_entry(const unsigned char *sha1,
1797 struct pack_entry *e,
1798 struct packed_git *p)
1799{
1800 off_t offset;
1801
1802 if (p->num_bad_objects) {
1803 unsigned i;
1804 for (i = 0; i < p->num_bad_objects; i++)
1805 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1806 return 0;
1807 }
1808
1809 offset = find_pack_entry_one(sha1, p);
1810 if (!offset)
1811 return 0;
1812
1813 /*
1814 * We are about to tell the caller where they can locate the
1815 * requested object. We better make sure the packfile is
1816 * still here and can be accessed before supplying that
1817 * answer, as it may have been deleted since the index was
1818 * loaded!
1819 */
1820 if (!is_pack_valid(p))
1821 return 0;
1822 e->offset = offset;
1823 e->p = p;
1824 hashcpy(e->sha1, sha1);
1825 return 1;
1826}
1827
1828/*
1829 * Iff a pack file contains the object named by sha1, return true and
1830 * store its location to e.
1831 */
1832int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1833{
1834 struct mru_entry *p;
1835
1836 prepare_packed_git();
1837 if (!packed_git)
1838 return 0;
1839
607bd831 1840 for (p = packed_git_mru.head; p; p = p->next) {
1a1e5d4f 1841 if (fill_pack_entry(sha1, e, p->item)) {
607bd831 1842 mru_mark(&packed_git_mru, p);
1a1e5d4f
JT
1843 return 1;
1844 }
1845 }
1846 return 0;
1847}
150e3001
JT
1848
1849int has_sha1_pack(const unsigned char *sha1)
1850{
1851 struct pack_entry e;
1852 return find_pack_entry(sha1, &e);
1853}
f9a8672a
JT
1854
1855int has_pack_index(const unsigned char *sha1)
1856{
1857 struct stat st;
1858 if (stat(sha1_pack_index_name(sha1), &st))
1859 return 0;
1860 return 1;
1861}
7709f468
JT
1862
1863static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
1864{
1865 uint32_t i;
1866 int r = 0;
1867
1868 for (i = 0; i < p->num_objects; i++) {
1869 struct object_id oid;
1870
1871 if (!nth_packed_object_oid(&oid, p, i))
1872 return error("unable to get sha1 of object %u in %s",
1873 i, p->pack_name);
1874
1875 r = cb(&oid, p, i, data);
1876 if (r)
1877 break;
1878 }
1879 return r;
1880}
1881
1882int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
1883{
1884 struct packed_git *p;
1885 int r = 0;
1886 int pack_errors = 0;
1887
1888 prepare_packed_git();
1889 for (p = packed_git; p; p = p->next) {
1890 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
1891 continue;
1892 if (open_pack_index(p)) {
1893 pack_errors = 1;
1894 continue;
1895 }
1896 r = for_each_object_in_pack(p, cb, data);
1897 if (r)
1898 break;
1899 }
1900 return r ? r : pack_errors;
1901}