sha1_loose_object_info: make type lookup optional
[git/git-svn.git] / sha1_file.c
blob285337819e3b9f8ca608a9e47e2e65fff8d725ce
1 /*
2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
6 * This handles basic git sha1 object files - packing, unpacking,
7 * creation etc.
8 */
9 #include "cache.h"
10 #include "string-list.h"
11 #include "delta.h"
12 #include "pack.h"
13 #include "blob.h"
14 #include "commit.h"
15 #include "run-command.h"
16 #include "tag.h"
17 #include "tree.h"
18 #include "tree-walk.h"
19 #include "refs.h"
20 #include "pack-revindex.h"
21 #include "sha1-lookup.h"
22 #include "bulk-checkin.h"
23 #include "streaming.h"
24 #include "dir.h"
26 #ifndef O_NOATIME
27 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
28 #define O_NOATIME 01000000
29 #else
30 #define O_NOATIME 0
31 #endif
32 #endif
34 #define SZ_FMT PRIuMAX
35 static inline uintmax_t sz_fmt(size_t s) { return s; }
37 const unsigned char null_sha1[20];
40 * This is meant to hold a *small* number of objects that you would
41 * want read_sha1_file() to be able to return, but yet you do not want
42 * to write them into the object store (e.g. a browse-only
43 * application).
45 static struct cached_object {
46 unsigned char sha1[20];
47 enum object_type type;
48 void *buf;
49 unsigned long size;
50 } *cached_objects;
51 static int cached_object_nr, cached_object_alloc;
53 static struct cached_object empty_tree = {
54 EMPTY_TREE_SHA1_BIN_LITERAL,
55 OBJ_TREE,
56 "",
60 static struct packed_git *last_found_pack;
62 static struct cached_object *find_cached_object(const unsigned char *sha1)
64 int i;
65 struct cached_object *co = cached_objects;
67 for (i = 0; i < cached_object_nr; i++, co++) {
68 if (!hashcmp(co->sha1, sha1))
69 return co;
71 if (!hashcmp(sha1, empty_tree.sha1))
72 return &empty_tree;
73 return NULL;
76 int mkdir_in_gitdir(const char *path)
78 if (mkdir(path, 0777)) {
79 int saved_errno = errno;
80 struct stat st;
81 struct strbuf sb = STRBUF_INIT;
83 if (errno != EEXIST)
84 return -1;
86 * Are we looking at a path in a symlinked worktree
87 * whose original repository does not yet have it?
88 * e.g. .git/rr-cache pointing at its original
89 * repository in which the user hasn't performed any
90 * conflict resolution yet?
92 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
93 strbuf_readlink(&sb, path, st.st_size) ||
94 !is_absolute_path(sb.buf) ||
95 mkdir(sb.buf, 0777)) {
96 strbuf_release(&sb);
97 errno = saved_errno;
98 return -1;
100 strbuf_release(&sb);
102 return adjust_shared_perm(path);
105 int safe_create_leading_directories(char *path)
107 char *pos = path + offset_1st_component(path);
108 struct stat st;
110 while (pos) {
111 pos = strchr(pos, '/');
112 if (!pos)
113 break;
114 while (*++pos == '/')
116 if (!*pos)
117 break;
118 *--pos = '\0';
119 if (!stat(path, &st)) {
120 /* path exists */
121 if (!S_ISDIR(st.st_mode)) {
122 *pos = '/';
123 return -3;
126 else if (mkdir(path, 0777)) {
127 if (errno == EEXIST &&
128 !stat(path, &st) && S_ISDIR(st.st_mode)) {
129 ; /* somebody created it since we checked */
130 } else {
131 *pos = '/';
132 return -1;
135 else if (adjust_shared_perm(path)) {
136 *pos = '/';
137 return -2;
139 *pos++ = '/';
141 return 0;
144 int safe_create_leading_directories_const(const char *path)
146 /* path points to cache entries, so xstrdup before messing with it */
147 char *buf = xstrdup(path);
148 int result = safe_create_leading_directories(buf);
149 free(buf);
150 return result;
153 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
155 int i;
156 for (i = 0; i < 20; i++) {
157 static char hex[] = "0123456789abcdef";
158 unsigned int val = sha1[i];
159 char *pos = pathbuf + i*2 + (i > 0);
160 *pos++ = hex[val >> 4];
161 *pos = hex[val & 0xf];
166 * NOTE! This returns a statically allocated buffer, so you have to be
167 * careful about using it. Do an "xstrdup()" if you need to save the
168 * filename.
170 * Also note that this returns the location for creating. Reading
171 * SHA1 file can happen from any alternate directory listed in the
172 * DB_ENVIRONMENT environment variable if it is not found in
173 * the primary object database.
175 char *sha1_file_name(const unsigned char *sha1)
177 static char buf[PATH_MAX];
178 const char *objdir;
179 int len;
181 objdir = get_object_directory();
182 len = strlen(objdir);
184 /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
185 if (len + 43 > PATH_MAX)
186 die("insanely long object directory %s", objdir);
187 memcpy(buf, objdir, len);
188 buf[len] = '/';
189 buf[len+3] = '/';
190 buf[len+42] = '\0';
191 fill_sha1_path(buf + len + 1, sha1);
192 return buf;
195 static char *sha1_get_pack_name(const unsigned char *sha1,
196 char **name, char **base, const char *which)
198 static const char hex[] = "0123456789abcdef";
199 char *buf;
200 int i;
202 if (!*base) {
203 const char *sha1_file_directory = get_object_directory();
204 int len = strlen(sha1_file_directory);
205 *base = xmalloc(len + 60);
206 sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
207 sha1_file_directory, which);
208 *name = *base + len + 11;
211 buf = *name;
213 for (i = 0; i < 20; i++) {
214 unsigned int val = *sha1++;
215 *buf++ = hex[val >> 4];
216 *buf++ = hex[val & 0xf];
219 return *base;
222 char *sha1_pack_name(const unsigned char *sha1)
224 static char *name, *base;
226 return sha1_get_pack_name(sha1, &name, &base, "pack");
229 char *sha1_pack_index_name(const unsigned char *sha1)
231 static char *name, *base;
233 return sha1_get_pack_name(sha1, &name, &base, "idx");
236 struct alternate_object_database *alt_odb_list;
237 static struct alternate_object_database **alt_odb_tail;
239 static int git_open_noatime(const char *name);
242 * Prepare alternate object database registry.
244 * The variable alt_odb_list points at the list of struct
245 * alternate_object_database. The elements on this list come from
246 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
247 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
248 * whose contents is similar to that environment variable but can be
249 * LF separated. Its base points at a statically allocated buffer that
250 * contains "/the/directory/corresponding/to/.git/objects/...", while
251 * its name points just after the slash at the end of ".git/objects/"
252 * in the example above, and has enough space to hold 40-byte hex
253 * SHA1, an extra slash for the first level indirection, and the
254 * terminating NUL.
256 static int link_alt_odb_entry(const char *entry, const char *relative_base, int depth)
258 const char *objdir = get_object_directory();
259 struct alternate_object_database *ent;
260 struct alternate_object_database *alt;
261 int pfxlen, entlen;
262 struct strbuf pathbuf = STRBUF_INIT;
264 if (!is_absolute_path(entry) && relative_base) {
265 strbuf_addstr(&pathbuf, real_path(relative_base));
266 strbuf_addch(&pathbuf, '/');
268 strbuf_addstr(&pathbuf, entry);
270 normalize_path_copy(pathbuf.buf, pathbuf.buf);
272 pfxlen = strlen(pathbuf.buf);
275 * The trailing slash after the directory name is given by
276 * this function at the end. Remove duplicates.
278 while (pfxlen && pathbuf.buf[pfxlen-1] == '/')
279 pfxlen -= 1;
281 entlen = pfxlen + 43; /* '/' + 2 hex + '/' + 38 hex + NUL */
282 ent = xmalloc(sizeof(*ent) + entlen);
283 memcpy(ent->base, pathbuf.buf, pfxlen);
284 strbuf_release(&pathbuf);
286 ent->name = ent->base + pfxlen + 1;
287 ent->base[pfxlen + 3] = '/';
288 ent->base[pfxlen] = ent->base[entlen-1] = 0;
290 /* Detect cases where alternate disappeared */
291 if (!is_directory(ent->base)) {
292 error("object directory %s does not exist; "
293 "check .git/objects/info/alternates.",
294 ent->base);
295 free(ent);
296 return -1;
299 /* Prevent the common mistake of listing the same
300 * thing twice, or object directory itself.
302 for (alt = alt_odb_list; alt; alt = alt->next) {
303 if (!memcmp(ent->base, alt->base, pfxlen)) {
304 free(ent);
305 return -1;
308 if (!strcmp(ent->base, objdir)) {
309 free(ent);
310 return -1;
313 /* add the alternate entry */
314 *alt_odb_tail = ent;
315 alt_odb_tail = &(ent->next);
316 ent->next = NULL;
318 /* recursively add alternates */
319 read_info_alternates(ent->base, depth + 1);
321 ent->base[pfxlen] = '/';
323 return 0;
326 static void link_alt_odb_entries(const char *alt, int len, int sep,
327 const char *relative_base, int depth)
329 struct string_list entries = STRING_LIST_INIT_NODUP;
330 char *alt_copy;
331 int i;
333 if (depth > 5) {
334 error("%s: ignoring alternate object stores, nesting too deep.",
335 relative_base);
336 return;
339 alt_copy = xmemdupz(alt, len);
340 string_list_split_in_place(&entries, alt_copy, sep, -1);
341 for (i = 0; i < entries.nr; i++) {
342 const char *entry = entries.items[i].string;
343 if (entry[0] == '\0' || entry[0] == '#')
344 continue;
345 if (!is_absolute_path(entry) && depth) {
346 error("%s: ignoring relative alternate object store %s",
347 relative_base, entry);
348 } else {
349 link_alt_odb_entry(entry, relative_base, depth);
352 string_list_clear(&entries, 0);
353 free(alt_copy);
356 void read_info_alternates(const char * relative_base, int depth)
358 char *map;
359 size_t mapsz;
360 struct stat st;
361 const char alt_file_name[] = "info/alternates";
362 /* Given that relative_base is no longer than PATH_MAX,
363 ensure that "path" has enough space to append "/", the
364 file name, "info/alternates", and a trailing NUL. */
365 char path[PATH_MAX + 1 + sizeof alt_file_name];
366 int fd;
368 sprintf(path, "%s/%s", relative_base, alt_file_name);
369 fd = git_open_noatime(path);
370 if (fd < 0)
371 return;
372 if (fstat(fd, &st) || (st.st_size == 0)) {
373 close(fd);
374 return;
376 mapsz = xsize_t(st.st_size);
377 map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
378 close(fd);
380 link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
382 munmap(map, mapsz);
385 void add_to_alternates_file(const char *reference)
387 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
388 int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR);
389 char *alt = mkpath("%s\n", reference);
390 write_or_die(fd, alt, strlen(alt));
391 if (commit_lock_file(lock))
392 die("could not close alternates file");
393 if (alt_odb_tail)
394 link_alt_odb_entries(alt, strlen(alt), '\n', NULL, 0);
397 void foreach_alt_odb(alt_odb_fn fn, void *cb)
399 struct alternate_object_database *ent;
401 prepare_alt_odb();
402 for (ent = alt_odb_list; ent; ent = ent->next)
403 if (fn(ent, cb))
404 return;
407 void prepare_alt_odb(void)
409 const char *alt;
411 if (alt_odb_tail)
412 return;
414 alt = getenv(ALTERNATE_DB_ENVIRONMENT);
415 if (!alt) alt = "";
417 alt_odb_tail = &alt_odb_list;
418 link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
420 read_info_alternates(get_object_directory(), 0);
423 static int has_loose_object_local(const unsigned char *sha1)
425 char *name = sha1_file_name(sha1);
426 return !access(name, F_OK);
429 int has_loose_object_nonlocal(const unsigned char *sha1)
431 struct alternate_object_database *alt;
432 prepare_alt_odb();
433 for (alt = alt_odb_list; alt; alt = alt->next) {
434 fill_sha1_path(alt->name, sha1);
435 if (!access(alt->base, F_OK))
436 return 1;
438 return 0;
441 static int has_loose_object(const unsigned char *sha1)
443 return has_loose_object_local(sha1) ||
444 has_loose_object_nonlocal(sha1);
447 static unsigned int pack_used_ctr;
448 static unsigned int pack_mmap_calls;
449 static unsigned int peak_pack_open_windows;
450 static unsigned int pack_open_windows;
451 static unsigned int pack_open_fds;
452 static unsigned int pack_max_fds;
453 static size_t peak_pack_mapped;
454 static size_t pack_mapped;
455 struct packed_git *packed_git;
457 void pack_report(void)
459 fprintf(stderr,
460 "pack_report: getpagesize() = %10" SZ_FMT "\n"
461 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
462 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
463 sz_fmt(getpagesize()),
464 sz_fmt(packed_git_window_size),
465 sz_fmt(packed_git_limit));
466 fprintf(stderr,
467 "pack_report: pack_used_ctr = %10u\n"
468 "pack_report: pack_mmap_calls = %10u\n"
469 "pack_report: pack_open_windows = %10u / %10u\n"
470 "pack_report: pack_mapped = "
471 "%10" SZ_FMT " / %10" SZ_FMT "\n",
472 pack_used_ctr,
473 pack_mmap_calls,
474 pack_open_windows, peak_pack_open_windows,
475 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
478 static int check_packed_git_idx(const char *path, struct packed_git *p)
480 void *idx_map;
481 struct pack_idx_header *hdr;
482 size_t idx_size;
483 uint32_t version, nr, i, *index;
484 int fd = git_open_noatime(path);
485 struct stat st;
487 if (fd < 0)
488 return -1;
489 if (fstat(fd, &st)) {
490 close(fd);
491 return -1;
493 idx_size = xsize_t(st.st_size);
494 if (idx_size < 4 * 256 + 20 + 20) {
495 close(fd);
496 return error("index file %s is too small", path);
498 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
499 close(fd);
501 hdr = idx_map;
502 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
503 version = ntohl(hdr->idx_version);
504 if (version < 2 || version > 2) {
505 munmap(idx_map, idx_size);
506 return error("index file %s is version %"PRIu32
507 " and is not supported by this binary"
508 " (try upgrading GIT to a newer version)",
509 path, version);
511 } else
512 version = 1;
514 nr = 0;
515 index = idx_map;
516 if (version > 1)
517 index += 2; /* skip index header */
518 for (i = 0; i < 256; i++) {
519 uint32_t n = ntohl(index[i]);
520 if (n < nr) {
521 munmap(idx_map, idx_size);
522 return error("non-monotonic index %s", path);
524 nr = n;
527 if (version == 1) {
529 * Total size:
530 * - 256 index entries 4 bytes each
531 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
532 * - 20-byte SHA1 of the packfile
533 * - 20-byte SHA1 file checksum
535 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
536 munmap(idx_map, idx_size);
537 return error("wrong index v1 file size in %s", path);
539 } else if (version == 2) {
541 * Minimum size:
542 * - 8 bytes of header
543 * - 256 index entries 4 bytes each
544 * - 20-byte sha1 entry * nr
545 * - 4-byte crc entry * nr
546 * - 4-byte offset entry * nr
547 * - 20-byte SHA1 of the packfile
548 * - 20-byte SHA1 file checksum
549 * And after the 4-byte offset table might be a
550 * variable sized table containing 8-byte entries
551 * for offsets larger than 2^31.
553 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
554 unsigned long max_size = min_size;
555 if (nr)
556 max_size += (nr - 1)*8;
557 if (idx_size < min_size || idx_size > max_size) {
558 munmap(idx_map, idx_size);
559 return error("wrong index v2 file size in %s", path);
561 if (idx_size != min_size &&
563 * make sure we can deal with large pack offsets.
564 * 31-bit signed offset won't be enough, neither
565 * 32-bit unsigned one will be.
567 (sizeof(off_t) <= 4)) {
568 munmap(idx_map, idx_size);
569 return error("pack too large for current definition of off_t in %s", path);
573 p->index_version = version;
574 p->index_data = idx_map;
575 p->index_size = idx_size;
576 p->num_objects = nr;
577 return 0;
580 int open_pack_index(struct packed_git *p)
582 char *idx_name;
583 int ret;
585 if (p->index_data)
586 return 0;
588 idx_name = xstrdup(p->pack_name);
589 strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
590 ret = check_packed_git_idx(idx_name, p);
591 free(idx_name);
592 return ret;
595 static void scan_windows(struct packed_git *p,
596 struct packed_git **lru_p,
597 struct pack_window **lru_w,
598 struct pack_window **lru_l)
600 struct pack_window *w, *w_l;
602 for (w_l = NULL, w = p->windows; w; w = w->next) {
603 if (!w->inuse_cnt) {
604 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
605 *lru_p = p;
606 *lru_w = w;
607 *lru_l = w_l;
610 w_l = w;
614 static int unuse_one_window(struct packed_git *current, int keep_fd)
616 struct packed_git *p, *lru_p = NULL;
617 struct pack_window *lru_w = NULL, *lru_l = NULL;
619 if (current)
620 scan_windows(current, &lru_p, &lru_w, &lru_l);
621 for (p = packed_git; p; p = p->next)
622 scan_windows(p, &lru_p, &lru_w, &lru_l);
623 if (lru_p) {
624 munmap(lru_w->base, lru_w->len);
625 pack_mapped -= lru_w->len;
626 if (lru_l)
627 lru_l->next = lru_w->next;
628 else {
629 lru_p->windows = lru_w->next;
630 if (!lru_p->windows && lru_p->pack_fd != -1
631 && lru_p->pack_fd != keep_fd) {
632 close(lru_p->pack_fd);
633 pack_open_fds--;
634 lru_p->pack_fd = -1;
637 free(lru_w);
638 pack_open_windows--;
639 return 1;
641 return 0;
644 void release_pack_memory(size_t need, int fd)
646 size_t cur = pack_mapped;
647 while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd))
648 ; /* nothing */
651 void *xmmap(void *start, size_t length,
652 int prot, int flags, int fd, off_t offset)
654 void *ret = mmap(start, length, prot, flags, fd, offset);
655 if (ret == MAP_FAILED) {
656 if (!length)
657 return NULL;
658 release_pack_memory(length, fd);
659 ret = mmap(start, length, prot, flags, fd, offset);
660 if (ret == MAP_FAILED)
661 die_errno("Out of memory? mmap failed");
663 return ret;
666 void close_pack_windows(struct packed_git *p)
668 while (p->windows) {
669 struct pack_window *w = p->windows;
671 if (w->inuse_cnt)
672 die("pack '%s' still has open windows to it",
673 p->pack_name);
674 munmap(w->base, w->len);
675 pack_mapped -= w->len;
676 pack_open_windows--;
677 p->windows = w->next;
678 free(w);
682 void unuse_pack(struct pack_window **w_cursor)
684 struct pack_window *w = *w_cursor;
685 if (w) {
686 w->inuse_cnt--;
687 *w_cursor = NULL;
691 void close_pack_index(struct packed_git *p)
693 if (p->index_data) {
694 munmap((void *)p->index_data, p->index_size);
695 p->index_data = NULL;
700 * This is used by git-repack in case a newly created pack happens to
701 * contain the same set of objects as an existing one. In that case
702 * the resulting file might be different even if its name would be the
703 * same. It is best to close any reference to the old pack before it is
704 * replaced on disk. Of course no index pointers nor windows for given pack
705 * must subsist at this point. If ever objects from this pack are requested
706 * again, the new version of the pack will be reinitialized through
707 * reprepare_packed_git().
709 void free_pack_by_name(const char *pack_name)
711 struct packed_git *p, **pp = &packed_git;
713 while (*pp) {
714 p = *pp;
715 if (strcmp(pack_name, p->pack_name) == 0) {
716 clear_delta_base_cache();
717 close_pack_windows(p);
718 if (p->pack_fd != -1) {
719 close(p->pack_fd);
720 pack_open_fds--;
722 close_pack_index(p);
723 free(p->bad_object_sha1);
724 *pp = p->next;
725 if (last_found_pack == p)
726 last_found_pack = NULL;
727 free(p);
728 return;
730 pp = &p->next;
734 static unsigned int get_max_fd_limit(void)
736 #ifdef RLIMIT_NOFILE
737 struct rlimit lim;
739 if (getrlimit(RLIMIT_NOFILE, &lim))
740 die_errno("cannot get RLIMIT_NOFILE");
742 return lim.rlim_cur;
743 #elif defined(_SC_OPEN_MAX)
744 return sysconf(_SC_OPEN_MAX);
745 #elif defined(OPEN_MAX)
746 return OPEN_MAX;
747 #else
748 return 1; /* see the caller ;-) */
749 #endif
753 * Do not call this directly as this leaks p->pack_fd on error return;
754 * call open_packed_git() instead.
756 static int open_packed_git_1(struct packed_git *p)
758 struct stat st;
759 struct pack_header hdr;
760 unsigned char sha1[20];
761 unsigned char *idx_sha1;
762 long fd_flag;
764 if (!p->index_data && open_pack_index(p))
765 return error("packfile %s index unavailable", p->pack_name);
767 if (!pack_max_fds) {
768 unsigned int max_fds = get_max_fd_limit();
770 /* Save 3 for stdin/stdout/stderr, 22 for work */
771 if (25 < max_fds)
772 pack_max_fds = max_fds - 25;
773 else
774 pack_max_fds = 1;
777 while (pack_max_fds <= pack_open_fds && unuse_one_window(NULL, -1))
778 ; /* nothing */
780 p->pack_fd = git_open_noatime(p->pack_name);
781 if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
782 return -1;
783 pack_open_fds++;
785 /* If we created the struct before we had the pack we lack size. */
786 if (!p->pack_size) {
787 if (!S_ISREG(st.st_mode))
788 return error("packfile %s not a regular file", p->pack_name);
789 p->pack_size = st.st_size;
790 } else if (p->pack_size != st.st_size)
791 return error("packfile %s size changed", p->pack_name);
793 /* We leave these file descriptors open with sliding mmap;
794 * there is no point keeping them open across exec(), though.
796 fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
797 if (fd_flag < 0)
798 return error("cannot determine file descriptor flags");
799 fd_flag |= FD_CLOEXEC;
800 if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
801 return error("cannot set FD_CLOEXEC");
803 /* Verify we recognize this pack file format. */
804 if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
805 return error("file %s is far too short to be a packfile", p->pack_name);
806 if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
807 return error("file %s is not a GIT packfile", p->pack_name);
808 if (!pack_version_ok(hdr.hdr_version))
809 return error("packfile %s is version %"PRIu32" and not"
810 " supported (try upgrading GIT to a newer version)",
811 p->pack_name, ntohl(hdr.hdr_version));
813 /* Verify the pack matches its index. */
814 if (p->num_objects != ntohl(hdr.hdr_entries))
815 return error("packfile %s claims to have %"PRIu32" objects"
816 " while index indicates %"PRIu32" objects",
817 p->pack_name, ntohl(hdr.hdr_entries),
818 p->num_objects);
819 if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
820 return error("end of packfile %s is unavailable", p->pack_name);
821 if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
822 return error("packfile %s signature is unavailable", p->pack_name);
823 idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
824 if (hashcmp(sha1, idx_sha1))
825 return error("packfile %s does not match index", p->pack_name);
826 return 0;
829 static int open_packed_git(struct packed_git *p)
831 if (!open_packed_git_1(p))
832 return 0;
833 if (p->pack_fd != -1) {
834 close(p->pack_fd);
835 pack_open_fds--;
836 p->pack_fd = -1;
838 return -1;
841 static int in_window(struct pack_window *win, off_t offset)
843 /* We must promise at least 20 bytes (one hash) after the
844 * offset is available from this window, otherwise the offset
845 * is not actually in this window and a different window (which
846 * has that one hash excess) must be used. This is to support
847 * the object header and delta base parsing routines below.
849 off_t win_off = win->offset;
850 return win_off <= offset
851 && (offset + 20) <= (win_off + win->len);
854 unsigned char *use_pack(struct packed_git *p,
855 struct pack_window **w_cursor,
856 off_t offset,
857 unsigned long *left)
859 struct pack_window *win = *w_cursor;
861 /* Since packfiles end in a hash of their content and it's
862 * pointless to ask for an offset into the middle of that
863 * hash, and the in_window function above wouldn't match
864 * don't allow an offset too close to the end of the file.
866 if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
867 die("packfile %s cannot be accessed", p->pack_name);
868 if (offset > (p->pack_size - 20))
869 die("offset beyond end of packfile (truncated pack?)");
871 if (!win || !in_window(win, offset)) {
872 if (win)
873 win->inuse_cnt--;
874 for (win = p->windows; win; win = win->next) {
875 if (in_window(win, offset))
876 break;
878 if (!win) {
879 size_t window_align = packed_git_window_size / 2;
880 off_t len;
882 if (p->pack_fd == -1 && open_packed_git(p))
883 die("packfile %s cannot be accessed", p->pack_name);
885 win = xcalloc(1, sizeof(*win));
886 win->offset = (offset / window_align) * window_align;
887 len = p->pack_size - win->offset;
888 if (len > packed_git_window_size)
889 len = packed_git_window_size;
890 win->len = (size_t)len;
891 pack_mapped += win->len;
892 while (packed_git_limit < pack_mapped
893 && unuse_one_window(p, p->pack_fd))
894 ; /* nothing */
895 win->base = xmmap(NULL, win->len,
896 PROT_READ, MAP_PRIVATE,
897 p->pack_fd, win->offset);
898 if (win->base == MAP_FAILED)
899 die("packfile %s cannot be mapped: %s",
900 p->pack_name,
901 strerror(errno));
902 if (!win->offset && win->len == p->pack_size
903 && !p->do_not_close) {
904 close(p->pack_fd);
905 pack_open_fds--;
906 p->pack_fd = -1;
908 pack_mmap_calls++;
909 pack_open_windows++;
910 if (pack_mapped > peak_pack_mapped)
911 peak_pack_mapped = pack_mapped;
912 if (pack_open_windows > peak_pack_open_windows)
913 peak_pack_open_windows = pack_open_windows;
914 win->next = p->windows;
915 p->windows = win;
918 if (win != *w_cursor) {
919 win->last_used = pack_used_ctr++;
920 win->inuse_cnt++;
921 *w_cursor = win;
923 offset -= win->offset;
924 if (left)
925 *left = win->len - xsize_t(offset);
926 return win->base + offset;
929 static struct packed_git *alloc_packed_git(int extra)
931 struct packed_git *p = xmalloc(sizeof(*p) + extra);
932 memset(p, 0, sizeof(*p));
933 p->pack_fd = -1;
934 return p;
937 static void try_to_free_pack_memory(size_t size)
939 release_pack_memory(size, -1);
942 struct packed_git *add_packed_git(const char *path, int path_len, int local)
944 static int have_set_try_to_free_routine;
945 struct stat st;
946 struct packed_git *p = alloc_packed_git(path_len + 2);
948 if (!have_set_try_to_free_routine) {
949 have_set_try_to_free_routine = 1;
950 set_try_to_free_routine(try_to_free_pack_memory);
954 * Make sure a corresponding .pack file exists and that
955 * the index looks sane.
957 path_len -= strlen(".idx");
958 if (path_len < 1) {
959 free(p);
960 return NULL;
962 memcpy(p->pack_name, path, path_len);
964 strcpy(p->pack_name + path_len, ".keep");
965 if (!access(p->pack_name, F_OK))
966 p->pack_keep = 1;
968 strcpy(p->pack_name + path_len, ".pack");
969 if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
970 free(p);
971 return NULL;
974 /* ok, it looks sane as far as we can check without
975 * actually mapping the pack file.
977 p->pack_size = st.st_size;
978 p->pack_local = local;
979 p->mtime = st.st_mtime;
980 if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
981 hashclr(p->sha1);
982 return p;
985 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
987 const char *path = sha1_pack_name(sha1);
988 struct packed_git *p = alloc_packed_git(strlen(path) + 1);
990 strcpy(p->pack_name, path);
991 hashcpy(p->sha1, sha1);
992 if (check_packed_git_idx(idx_path, p)) {
993 free(p);
994 return NULL;
997 return p;
1000 void install_packed_git(struct packed_git *pack)
1002 if (pack->pack_fd != -1)
1003 pack_open_fds++;
1005 pack->next = packed_git;
1006 packed_git = pack;
1009 void (*report_garbage)(const char *desc, const char *path);
1011 static void report_helper(const struct string_list *list,
1012 int seen_bits, int first, int last)
1014 const char *msg;
1015 switch (seen_bits) {
1016 case 0:
1017 msg = "no corresponding .idx nor .pack";
1018 break;
1019 case 1:
1020 msg = "no corresponding .idx";
1021 break;
1022 case 2:
1023 msg = "no corresponding .pack";
1024 break;
1025 default:
1026 return;
1028 for (; first < last; first++)
1029 report_garbage(msg, list->items[first].string);
1032 static void report_pack_garbage(struct string_list *list)
1034 int i, baselen = -1, first = 0, seen_bits = 0;
1036 if (!report_garbage)
1037 return;
1039 sort_string_list(list);
1041 for (i = 0; i < list->nr; i++) {
1042 const char *path = list->items[i].string;
1043 if (baselen != -1 &&
1044 strncmp(path, list->items[first].string, baselen)) {
1045 report_helper(list, seen_bits, first, i);
1046 baselen = -1;
1047 seen_bits = 0;
1049 if (baselen == -1) {
1050 const char *dot = strrchr(path, '.');
1051 if (!dot) {
1052 report_garbage("garbage found", path);
1053 continue;
1055 baselen = dot - path + 1;
1056 first = i;
1058 if (!strcmp(path + baselen, "pack"))
1059 seen_bits |= 1;
1060 else if (!strcmp(path + baselen, "idx"))
1061 seen_bits |= 2;
1063 report_helper(list, seen_bits, first, list->nr);
1066 static void prepare_packed_git_one(char *objdir, int local)
1068 /* Ensure that this buffer is large enough so that we can
1069 append "/pack/" without clobbering the stack even if
1070 strlen(objdir) were PATH_MAX. */
1071 char path[PATH_MAX + 1 + 4 + 1 + 1];
1072 int len;
1073 DIR *dir;
1074 struct dirent *de;
1075 struct string_list garbage = STRING_LIST_INIT_DUP;
1077 sprintf(path, "%s/pack", objdir);
1078 len = strlen(path);
1079 dir = opendir(path);
1080 if (!dir) {
1081 if (errno != ENOENT)
1082 error("unable to open object pack directory: %s: %s",
1083 path, strerror(errno));
1084 return;
1086 path[len++] = '/';
1087 while ((de = readdir(dir)) != NULL) {
1088 int namelen = strlen(de->d_name);
1089 struct packed_git *p;
1091 if (len + namelen + 1 > sizeof(path)) {
1092 if (report_garbage) {
1093 struct strbuf sb = STRBUF_INIT;
1094 strbuf_addf(&sb, "%.*s/%s", len - 1, path, de->d_name);
1095 report_garbage("path too long", sb.buf);
1096 strbuf_release(&sb);
1098 continue;
1101 if (is_dot_or_dotdot(de->d_name))
1102 continue;
1104 strcpy(path + len, de->d_name);
1106 if (has_extension(de->d_name, ".idx")) {
1107 /* Don't reopen a pack we already have. */
1108 for (p = packed_git; p; p = p->next) {
1109 if (!memcmp(path, p->pack_name, len + namelen - 4))
1110 break;
1112 if (p == NULL &&
1114 * See if it really is a valid .idx file with
1115 * corresponding .pack file that we can map.
1117 (p = add_packed_git(path, len + namelen, local)) != NULL)
1118 install_packed_git(p);
1121 if (!report_garbage)
1122 continue;
1124 if (has_extension(de->d_name, ".idx") ||
1125 has_extension(de->d_name, ".pack") ||
1126 has_extension(de->d_name, ".keep"))
1127 string_list_append(&garbage, path);
1128 else
1129 report_garbage("garbage found", path);
1131 closedir(dir);
1132 report_pack_garbage(&garbage);
1133 string_list_clear(&garbage, 0);
1136 static int sort_pack(const void *a_, const void *b_)
1138 struct packed_git *a = *((struct packed_git **)a_);
1139 struct packed_git *b = *((struct packed_git **)b_);
1140 int st;
1143 * Local packs tend to contain objects specific to our
1144 * variant of the project than remote ones. In addition,
1145 * remote ones could be on a network mounted filesystem.
1146 * Favor local ones for these reasons.
1148 st = a->pack_local - b->pack_local;
1149 if (st)
1150 return -st;
1153 * Younger packs tend to contain more recent objects,
1154 * and more recent objects tend to get accessed more
1155 * often.
1157 if (a->mtime < b->mtime)
1158 return 1;
1159 else if (a->mtime == b->mtime)
1160 return 0;
1161 return -1;
1164 static void rearrange_packed_git(void)
1166 struct packed_git **ary, *p;
1167 int i, n;
1169 for (n = 0, p = packed_git; p; p = p->next)
1170 n++;
1171 if (n < 2)
1172 return;
1174 /* prepare an array of packed_git for easier sorting */
1175 ary = xcalloc(n, sizeof(struct packed_git *));
1176 for (n = 0, p = packed_git; p; p = p->next)
1177 ary[n++] = p;
1179 qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1181 /* link them back again */
1182 for (i = 0; i < n - 1; i++)
1183 ary[i]->next = ary[i + 1];
1184 ary[n - 1]->next = NULL;
1185 packed_git = ary[0];
1187 free(ary);
1190 static int prepare_packed_git_run_once = 0;
1191 void prepare_packed_git(void)
1193 struct alternate_object_database *alt;
1195 if (prepare_packed_git_run_once)
1196 return;
1197 prepare_packed_git_one(get_object_directory(), 1);
1198 prepare_alt_odb();
1199 for (alt = alt_odb_list; alt; alt = alt->next) {
1200 alt->name[-1] = 0;
1201 prepare_packed_git_one(alt->base, 0);
1202 alt->name[-1] = '/';
1204 rearrange_packed_git();
1205 prepare_packed_git_run_once = 1;
1208 void reprepare_packed_git(void)
1210 discard_revindex();
1211 prepare_packed_git_run_once = 0;
1212 prepare_packed_git();
1215 static void mark_bad_packed_object(struct packed_git *p,
1216 const unsigned char *sha1)
1218 unsigned i;
1219 for (i = 0; i < p->num_bad_objects; i++)
1220 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1221 return;
1222 p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1));
1223 hashcpy(p->bad_object_sha1 + 20 * p->num_bad_objects, sha1);
1224 p->num_bad_objects++;
1227 static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1229 struct packed_git *p;
1230 unsigned i;
1232 for (p = packed_git; p; p = p->next)
1233 for (i = 0; i < p->num_bad_objects; i++)
1234 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1235 return p;
1236 return NULL;
1240 * With an in-core object data in "map", rehash it to make sure the
1241 * object name actually matches "sha1" to detect object corruption.
1242 * With "map" == NULL, try reading the object named with "sha1" using
1243 * the streaming interface and rehash it to do the same.
1245 int check_sha1_signature(const unsigned char *sha1, void *map,
1246 unsigned long size, const char *type)
1248 unsigned char real_sha1[20];
1249 enum object_type obj_type;
1250 struct git_istream *st;
1251 git_SHA_CTX c;
1252 char hdr[32];
1253 int hdrlen;
1255 if (map) {
1256 hash_sha1_file(map, size, type, real_sha1);
1257 return hashcmp(sha1, real_sha1) ? -1 : 0;
1260 st = open_istream(sha1, &obj_type, &size, NULL);
1261 if (!st)
1262 return -1;
1264 /* Generate the header */
1265 hdrlen = sprintf(hdr, "%s %lu", typename(obj_type), size) + 1;
1267 /* Sha1.. */
1268 git_SHA1_Init(&c);
1269 git_SHA1_Update(&c, hdr, hdrlen);
1270 for (;;) {
1271 char buf[1024 * 16];
1272 ssize_t readlen = read_istream(st, buf, sizeof(buf));
1274 if (readlen < 0) {
1275 close_istream(st);
1276 return -1;
1278 if (!readlen)
1279 break;
1280 git_SHA1_Update(&c, buf, readlen);
1282 git_SHA1_Final(real_sha1, &c);
1283 close_istream(st);
1284 return hashcmp(sha1, real_sha1) ? -1 : 0;
1287 static int git_open_noatime(const char *name)
1289 static int sha1_file_open_flag = O_NOATIME;
1291 for (;;) {
1292 int fd = open(name, O_RDONLY | sha1_file_open_flag);
1293 if (fd >= 0)
1294 return fd;
1296 /* Might the failure be due to O_NOATIME? */
1297 if (errno != ENOENT && sha1_file_open_flag) {
1298 sha1_file_open_flag = 0;
1299 continue;
1302 return -1;
1306 static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
1308 char *name = sha1_file_name(sha1);
1309 struct alternate_object_database *alt;
1311 if (!lstat(name, st))
1312 return 0;
1314 prepare_alt_odb();
1315 errno = ENOENT;
1316 for (alt = alt_odb_list; alt; alt = alt->next) {
1317 name = alt->name;
1318 fill_sha1_path(name, sha1);
1319 if (!lstat(alt->base, st))
1320 return 0;
1323 return -1;
1326 static int open_sha1_file(const unsigned char *sha1)
1328 int fd;
1329 char *name = sha1_file_name(sha1);
1330 struct alternate_object_database *alt;
1332 fd = git_open_noatime(name);
1333 if (fd >= 0)
1334 return fd;
1336 prepare_alt_odb();
1337 errno = ENOENT;
1338 for (alt = alt_odb_list; alt; alt = alt->next) {
1339 name = alt->name;
1340 fill_sha1_path(name, sha1);
1341 fd = git_open_noatime(alt->base);
1342 if (fd >= 0)
1343 return fd;
1345 return -1;
1348 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1350 void *map;
1351 int fd;
1353 fd = open_sha1_file(sha1);
1354 map = NULL;
1355 if (fd >= 0) {
1356 struct stat st;
1358 if (!fstat(fd, &st)) {
1359 *size = xsize_t(st.st_size);
1360 if (!*size) {
1361 /* mmap() is forbidden on empty files */
1362 error("object file %s is empty", sha1_file_name(sha1));
1363 return NULL;
1365 map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1367 close(fd);
1369 return map;
1373 * There used to be a second loose object header format which
1374 * was meant to mimic the in-pack format, allowing for direct
1375 * copy of the object data. This format turned up not to be
1376 * really worth it and we no longer write loose objects in that
1377 * format.
1379 static int experimental_loose_object(unsigned char *map)
1381 unsigned int word;
1384 * We must determine if the buffer contains the standard
1385 * zlib-deflated stream or the experimental format based
1386 * on the in-pack object format. Compare the header byte
1387 * for each format:
1389 * RFC1950 zlib w/ deflate : 0www1000 : 0 <= www <= 7
1390 * Experimental pack-based : Stttssss : ttt = 1,2,3,4
1392 * If bit 7 is clear and bits 0-3 equal 8, the buffer MUST be
1393 * in standard loose-object format, UNLESS it is a Git-pack
1394 * format object *exactly* 8 bytes in size when inflated.
1396 * However, RFC1950 also specifies that the 1st 16-bit word
1397 * must be divisible by 31 - this checksum tells us our buffer
1398 * is in the standard format, giving a false positive only if
1399 * the 1st word of the Git-pack format object happens to be
1400 * divisible by 31, ie:
1401 * ((byte0 * 256) + byte1) % 31 = 0
1402 * => 0ttt10000www1000 % 31 = 0
1404 * As it happens, this case can only arise for www=3 & ttt=1
1405 * - ie, a Commit object, which would have to be 8 bytes in
1406 * size. As no Commit can be that small, we find that the
1407 * combination of these two criteria (bitmask & checksum)
1408 * can always correctly determine the buffer format.
1410 word = (map[0] << 8) + map[1];
1411 if ((map[0] & 0x8F) == 0x08 && !(word % 31))
1412 return 0;
1413 else
1414 return 1;
1417 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1418 unsigned long len, enum object_type *type, unsigned long *sizep)
1420 unsigned shift;
1421 unsigned long size, c;
1422 unsigned long used = 0;
1424 c = buf[used++];
1425 *type = (c >> 4) & 7;
1426 size = c & 15;
1427 shift = 4;
1428 while (c & 0x80) {
1429 if (len <= used || bitsizeof(long) <= shift) {
1430 error("bad object header");
1431 size = used = 0;
1432 break;
1434 c = buf[used++];
1435 size += (c & 0x7f) << shift;
1436 shift += 7;
1438 *sizep = size;
1439 return used;
1442 int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1444 unsigned long size, used;
1445 static const char valid_loose_object_type[8] = {
1446 0, /* OBJ_EXT */
1447 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
1448 0, /* "delta" and others are invalid in a loose object */
1450 enum object_type type;
1452 /* Get the data stream */
1453 memset(stream, 0, sizeof(*stream));
1454 stream->next_in = map;
1455 stream->avail_in = mapsize;
1456 stream->next_out = buffer;
1457 stream->avail_out = bufsiz;
1459 if (experimental_loose_object(map)) {
1461 * The old experimental format we no longer produce;
1462 * we can still read it.
1464 used = unpack_object_header_buffer(map, mapsize, &type, &size);
1465 if (!used || !valid_loose_object_type[type])
1466 return -1;
1467 map += used;
1468 mapsize -= used;
1470 /* Set up the stream for the rest.. */
1471 stream->next_in = map;
1472 stream->avail_in = mapsize;
1473 git_inflate_init(stream);
1475 /* And generate the fake traditional header */
1476 stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
1477 typename(type), size);
1478 return 0;
1480 git_inflate_init(stream);
1481 return git_inflate(stream, 0);
1484 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1486 int bytes = strlen(buffer) + 1;
1487 unsigned char *buf = xmallocz(size);
1488 unsigned long n;
1489 int status = Z_OK;
1491 n = stream->total_out - bytes;
1492 if (n > size)
1493 n = size;
1494 memcpy(buf, (char *) buffer + bytes, n);
1495 bytes = n;
1496 if (bytes <= size) {
1498 * The above condition must be (bytes <= size), not
1499 * (bytes < size). In other words, even though we
1500 * expect no more output and set avail_out to zero,
1501 * the input zlib stream may have bytes that express
1502 * "this concludes the stream", and we *do* want to
1503 * eat that input.
1505 * Otherwise we would not be able to test that we
1506 * consumed all the input to reach the expected size;
1507 * we also want to check that zlib tells us that all
1508 * went well with status == Z_STREAM_END at the end.
1510 stream->next_out = buf + bytes;
1511 stream->avail_out = size - bytes;
1512 while (status == Z_OK)
1513 status = git_inflate(stream, Z_FINISH);
1515 if (status == Z_STREAM_END && !stream->avail_in) {
1516 git_inflate_end(stream);
1517 return buf;
1520 if (status < 0)
1521 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1522 else if (stream->avail_in)
1523 error("garbage at end of loose object '%s'",
1524 sha1_to_hex(sha1));
1525 free(buf);
1526 return NULL;
1530 * We used to just use "sscanf()", but that's actually way
1531 * too permissive for what we want to check. So do an anal
1532 * object header parse by hand.
1534 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1536 char type[10];
1537 int i;
1538 unsigned long size;
1541 * The type can be at most ten bytes (including the
1542 * terminating '\0' that we add), and is followed by
1543 * a space.
1545 i = 0;
1546 for (;;) {
1547 char c = *hdr++;
1548 if (c == ' ')
1549 break;
1550 type[i++] = c;
1551 if (i >= sizeof(type))
1552 return -1;
1554 type[i] = 0;
1557 * The length must follow immediately, and be in canonical
1558 * decimal format (ie "010" is not valid).
1560 size = *hdr++ - '0';
1561 if (size > 9)
1562 return -1;
1563 if (size) {
1564 for (;;) {
1565 unsigned long c = *hdr - '0';
1566 if (c > 9)
1567 break;
1568 hdr++;
1569 size = size * 10 + c;
1572 *sizep = size;
1575 * The length must be followed by a zero byte
1577 return *hdr ? -1 : type_from_string(type);
1580 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1582 int ret;
1583 git_zstream stream;
1584 char hdr[8192];
1586 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1587 if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1588 return NULL;
1590 return unpack_sha1_rest(&stream, hdr, *size, sha1);
1593 unsigned long get_size_from_delta(struct packed_git *p,
1594 struct pack_window **w_curs,
1595 off_t curpos)
1597 const unsigned char *data;
1598 unsigned char delta_head[20], *in;
1599 git_zstream stream;
1600 int st;
1602 memset(&stream, 0, sizeof(stream));
1603 stream.next_out = delta_head;
1604 stream.avail_out = sizeof(delta_head);
1606 git_inflate_init(&stream);
1607 do {
1608 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1609 stream.next_in = in;
1610 st = git_inflate(&stream, Z_FINISH);
1611 curpos += stream.next_in - in;
1612 } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1613 stream.total_out < sizeof(delta_head));
1614 git_inflate_end(&stream);
1615 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1616 error("delta data unpack-initial failed");
1617 return 0;
1620 /* Examine the initial part of the delta to figure out
1621 * the result size.
1623 data = delta_head;
1625 /* ignore base size */
1626 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1628 /* Read the result size */
1629 return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1632 static off_t get_delta_base(struct packed_git *p,
1633 struct pack_window **w_curs,
1634 off_t *curpos,
1635 enum object_type type,
1636 off_t delta_obj_offset)
1638 unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1639 off_t base_offset;
1641 /* use_pack() assured us we have [base_info, base_info + 20)
1642 * as a range that we can look at without walking off the
1643 * end of the mapped window. Its actually the hash size
1644 * that is assured. An OFS_DELTA longer than the hash size
1645 * is stupid, as then a REF_DELTA would be smaller to store.
1647 if (type == OBJ_OFS_DELTA) {
1648 unsigned used = 0;
1649 unsigned char c = base_info[used++];
1650 base_offset = c & 127;
1651 while (c & 128) {
1652 base_offset += 1;
1653 if (!base_offset || MSB(base_offset, 7))
1654 return 0; /* overflow */
1655 c = base_info[used++];
1656 base_offset = (base_offset << 7) + (c & 127);
1658 base_offset = delta_obj_offset - base_offset;
1659 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1660 return 0; /* out of bound */
1661 *curpos += used;
1662 } else if (type == OBJ_REF_DELTA) {
1663 /* The base entry _must_ be in the same pack */
1664 base_offset = find_pack_entry_one(base_info, p);
1665 *curpos += 20;
1666 } else
1667 die("I am totally screwed");
1668 return base_offset;
1671 int unpack_object_header(struct packed_git *p,
1672 struct pack_window **w_curs,
1673 off_t *curpos,
1674 unsigned long *sizep)
1676 unsigned char *base;
1677 unsigned long left;
1678 unsigned long used;
1679 enum object_type type;
1681 /* use_pack() assures us we have [base, base + 20) available
1682 * as a range that we can look at. (Its actually the hash
1683 * size that is assured.) With our object header encoding
1684 * the maximum deflated object size is 2^137, which is just
1685 * insane, so we know won't exceed what we have been given.
1687 base = use_pack(p, w_curs, *curpos, &left);
1688 used = unpack_object_header_buffer(base, left, &type, sizep);
1689 if (!used) {
1690 type = OBJ_BAD;
1691 } else
1692 *curpos += used;
1694 return type;
1697 static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
1699 int type;
1700 struct revindex_entry *revidx;
1701 const unsigned char *sha1;
1702 revidx = find_pack_revindex(p, obj_offset);
1703 if (!revidx)
1704 return OBJ_BAD;
1705 sha1 = nth_packed_object_sha1(p, revidx->nr);
1706 mark_bad_packed_object(p, sha1);
1707 type = sha1_object_info(sha1, NULL);
1708 if (type <= OBJ_NONE)
1709 return OBJ_BAD;
1710 return type;
1714 #define POI_STACK_PREALLOC 64
1716 static int packed_object_info(struct packed_git *p, off_t obj_offset,
1717 unsigned long *sizep, int *rtype,
1718 unsigned long *disk_sizep)
1720 struct pack_window *w_curs = NULL;
1721 unsigned long size;
1722 off_t curpos = obj_offset;
1723 enum object_type type;
1724 off_t small_poi_stack[POI_STACK_PREALLOC];
1725 off_t *poi_stack = small_poi_stack;
1726 int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1728 type = unpack_object_header(p, &w_curs, &curpos, &size);
1730 if (rtype)
1731 *rtype = type; /* representation type */
1733 if (sizep) {
1734 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1735 off_t tmp_pos = curpos;
1736 off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1737 type, obj_offset);
1738 if (!base_offset) {
1739 type = OBJ_BAD;
1740 goto out;
1742 *sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1743 if (*sizep == 0) {
1744 type = OBJ_BAD;
1745 goto out;
1747 } else {
1748 *sizep = size;
1752 if (disk_sizep) {
1753 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1754 *disk_sizep = revidx[1].offset - obj_offset;
1757 while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1758 off_t base_offset;
1759 /* Push the object we're going to leave behind */
1760 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1761 poi_stack_alloc = alloc_nr(poi_stack_nr);
1762 poi_stack = xmalloc(sizeof(off_t)*poi_stack_alloc);
1763 memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1764 } else {
1765 ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1767 poi_stack[poi_stack_nr++] = obj_offset;
1768 /* If parsing the base offset fails, just unwind */
1769 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1770 if (!base_offset)
1771 goto unwind;
1772 curpos = obj_offset = base_offset;
1773 type = unpack_object_header(p, &w_curs, &curpos, &size);
1774 if (type <= OBJ_NONE) {
1775 /* If getting the base itself fails, we first
1776 * retry the base, otherwise unwind */
1777 type = retry_bad_packed_offset(p, base_offset);
1778 if (type > OBJ_NONE)
1779 goto out;
1780 goto unwind;
1784 switch (type) {
1785 case OBJ_BAD:
1786 case OBJ_COMMIT:
1787 case OBJ_TREE:
1788 case OBJ_BLOB:
1789 case OBJ_TAG:
1790 break;
1791 default:
1792 error("unknown object type %i at offset %"PRIuMAX" in %s",
1793 type, (uintmax_t)obj_offset, p->pack_name);
1794 type = OBJ_BAD;
1797 out:
1798 if (poi_stack != small_poi_stack)
1799 free(poi_stack);
1800 unuse_pack(&w_curs);
1801 return type;
1803 unwind:
1804 while (poi_stack_nr) {
1805 obj_offset = poi_stack[--poi_stack_nr];
1806 type = retry_bad_packed_offset(p, obj_offset);
1807 if (type > OBJ_NONE)
1808 goto out;
1810 type = OBJ_BAD;
1811 goto out;
1814 static void *unpack_compressed_entry(struct packed_git *p,
1815 struct pack_window **w_curs,
1816 off_t curpos,
1817 unsigned long size)
1819 int st;
1820 git_zstream stream;
1821 unsigned char *buffer, *in;
1823 buffer = xmallocz(size);
1824 memset(&stream, 0, sizeof(stream));
1825 stream.next_out = buffer;
1826 stream.avail_out = size + 1;
1828 git_inflate_init(&stream);
1829 do {
1830 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1831 stream.next_in = in;
1832 st = git_inflate(&stream, Z_FINISH);
1833 if (!stream.avail_out)
1834 break; /* the payload is larger than it should be */
1835 curpos += stream.next_in - in;
1836 } while (st == Z_OK || st == Z_BUF_ERROR);
1837 git_inflate_end(&stream);
1838 if ((st != Z_STREAM_END) || stream.total_out != size) {
1839 free(buffer);
1840 return NULL;
1843 return buffer;
1846 #define MAX_DELTA_CACHE (256)
1848 static size_t delta_base_cached;
1850 static struct delta_base_cache_lru_list {
1851 struct delta_base_cache_lru_list *prev;
1852 struct delta_base_cache_lru_list *next;
1853 } delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
1855 static struct delta_base_cache_entry {
1856 struct delta_base_cache_lru_list lru;
1857 void *data;
1858 struct packed_git *p;
1859 off_t base_offset;
1860 unsigned long size;
1861 enum object_type type;
1862 } delta_base_cache[MAX_DELTA_CACHE];
1864 static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
1866 unsigned long hash;
1868 hash = (unsigned long)p + (unsigned long)base_offset;
1869 hash += (hash >> 8) + (hash >> 16);
1870 return hash % MAX_DELTA_CACHE;
1873 static struct delta_base_cache_entry *
1874 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1876 unsigned long hash = pack_entry_hash(p, base_offset);
1877 return delta_base_cache + hash;
1880 static int eq_delta_base_cache_entry(struct delta_base_cache_entry *ent,
1881 struct packed_git *p, off_t base_offset)
1883 return (ent->data && ent->p == p && ent->base_offset == base_offset);
1886 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1888 struct delta_base_cache_entry *ent;
1889 ent = get_delta_base_cache_entry(p, base_offset);
1890 return eq_delta_base_cache_entry(ent, p, base_offset);
1893 static void clear_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1895 ent->data = NULL;
1896 ent->lru.next->prev = ent->lru.prev;
1897 ent->lru.prev->next = ent->lru.next;
1898 delta_base_cached -= ent->size;
1901 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1902 unsigned long *base_size, enum object_type *type, int keep_cache)
1904 struct delta_base_cache_entry *ent;
1905 void *ret;
1907 ent = get_delta_base_cache_entry(p, base_offset);
1909 if (!eq_delta_base_cache_entry(ent, p, base_offset))
1910 return unpack_entry(p, base_offset, type, base_size);
1912 ret = ent->data;
1914 if (!keep_cache)
1915 clear_delta_base_cache_entry(ent);
1916 else
1917 ret = xmemdupz(ent->data, ent->size);
1918 *type = ent->type;
1919 *base_size = ent->size;
1920 return ret;
1923 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1925 if (ent->data) {
1926 free(ent->data);
1927 ent->data = NULL;
1928 ent->lru.next->prev = ent->lru.prev;
1929 ent->lru.prev->next = ent->lru.next;
1930 delta_base_cached -= ent->size;
1934 void clear_delta_base_cache(void)
1936 unsigned long p;
1937 for (p = 0; p < MAX_DELTA_CACHE; p++)
1938 release_delta_base_cache(&delta_base_cache[p]);
1941 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1942 void *base, unsigned long base_size, enum object_type type)
1944 unsigned long hash = pack_entry_hash(p, base_offset);
1945 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1946 struct delta_base_cache_lru_list *lru;
1948 release_delta_base_cache(ent);
1949 delta_base_cached += base_size;
1951 for (lru = delta_base_cache_lru.next;
1952 delta_base_cached > delta_base_cache_limit
1953 && lru != &delta_base_cache_lru;
1954 lru = lru->next) {
1955 struct delta_base_cache_entry *f = (void *)lru;
1956 if (f->type == OBJ_BLOB)
1957 release_delta_base_cache(f);
1959 for (lru = delta_base_cache_lru.next;
1960 delta_base_cached > delta_base_cache_limit
1961 && lru != &delta_base_cache_lru;
1962 lru = lru->next) {
1963 struct delta_base_cache_entry *f = (void *)lru;
1964 release_delta_base_cache(f);
1967 ent->p = p;
1968 ent->base_offset = base_offset;
1969 ent->type = type;
1970 ent->data = base;
1971 ent->size = base_size;
1972 ent->lru.next = &delta_base_cache_lru;
1973 ent->lru.prev = delta_base_cache_lru.prev;
1974 delta_base_cache_lru.prev->next = &ent->lru;
1975 delta_base_cache_lru.prev = &ent->lru;
1978 static void *read_object(const unsigned char *sha1, enum object_type *type,
1979 unsigned long *size);
1981 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1983 static FILE *log_file;
1985 if (!log_file) {
1986 log_file = fopen(log_pack_access, "w");
1987 if (!log_file) {
1988 error("cannot open pack access log '%s' for writing: %s",
1989 log_pack_access, strerror(errno));
1990 log_pack_access = NULL;
1991 return;
1994 fprintf(log_file, "%s %"PRIuMAX"\n",
1995 p->pack_name, (uintmax_t)obj_offset);
1996 fflush(log_file);
1999 int do_check_packed_object_crc;
2001 #define UNPACK_ENTRY_STACK_PREALLOC 64
2002 struct unpack_entry_stack_ent {
2003 off_t obj_offset;
2004 off_t curpos;
2005 unsigned long size;
2008 void *unpack_entry(struct packed_git *p, off_t obj_offset,
2009 enum object_type *final_type, unsigned long *final_size)
2011 struct pack_window *w_curs = NULL;
2012 off_t curpos = obj_offset;
2013 void *data = NULL;
2014 unsigned long size;
2015 enum object_type type;
2016 struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
2017 struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
2018 int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
2019 int base_from_cache = 0;
2021 if (log_pack_access)
2022 write_pack_access_log(p, obj_offset);
2024 /* PHASE 1: drill down to the innermost base object */
2025 for (;;) {
2026 off_t base_offset;
2027 int i;
2028 struct delta_base_cache_entry *ent;
2030 if (do_check_packed_object_crc && p->index_version > 1) {
2031 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2032 unsigned long len = revidx[1].offset - obj_offset;
2033 if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
2034 const unsigned char *sha1 =
2035 nth_packed_object_sha1(p, revidx->nr);
2036 error("bad packed object CRC for %s",
2037 sha1_to_hex(sha1));
2038 mark_bad_packed_object(p, sha1);
2039 unuse_pack(&w_curs);
2040 return NULL;
2044 ent = get_delta_base_cache_entry(p, curpos);
2045 if (eq_delta_base_cache_entry(ent, p, curpos)) {
2046 type = ent->type;
2047 data = ent->data;
2048 size = ent->size;
2049 clear_delta_base_cache_entry(ent);
2050 base_from_cache = 1;
2051 break;
2054 type = unpack_object_header(p, &w_curs, &curpos, &size);
2055 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
2056 break;
2058 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
2059 if (!base_offset) {
2060 error("failed to validate delta base reference "
2061 "at offset %"PRIuMAX" from %s",
2062 (uintmax_t)curpos, p->pack_name);
2063 /* bail to phase 2, in hopes of recovery */
2064 data = NULL;
2065 break;
2068 /* push object, proceed to base */
2069 if (delta_stack_nr >= delta_stack_alloc
2070 && delta_stack == small_delta_stack) {
2071 delta_stack_alloc = alloc_nr(delta_stack_nr);
2072 delta_stack = xmalloc(sizeof(*delta_stack)*delta_stack_alloc);
2073 memcpy(delta_stack, small_delta_stack,
2074 sizeof(*delta_stack)*delta_stack_nr);
2075 } else {
2076 ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
2078 i = delta_stack_nr++;
2079 delta_stack[i].obj_offset = obj_offset;
2080 delta_stack[i].curpos = curpos;
2081 delta_stack[i].size = size;
2083 curpos = obj_offset = base_offset;
2086 /* PHASE 2: handle the base */
2087 switch (type) {
2088 case OBJ_OFS_DELTA:
2089 case OBJ_REF_DELTA:
2090 if (data)
2091 die("BUG in unpack_entry: left loop at a valid delta");
2092 break;
2093 case OBJ_COMMIT:
2094 case OBJ_TREE:
2095 case OBJ_BLOB:
2096 case OBJ_TAG:
2097 if (!base_from_cache)
2098 data = unpack_compressed_entry(p, &w_curs, curpos, size);
2099 break;
2100 default:
2101 data = NULL;
2102 error("unknown object type %i at offset %"PRIuMAX" in %s",
2103 type, (uintmax_t)obj_offset, p->pack_name);
2106 /* PHASE 3: apply deltas in order */
2108 /* invariants:
2109 * 'data' holds the base data, or NULL if there was corruption
2111 while (delta_stack_nr) {
2112 void *delta_data;
2113 void *base = data;
2114 unsigned long delta_size, base_size = size;
2115 int i;
2117 data = NULL;
2119 if (base)
2120 add_delta_base_cache(p, obj_offset, base, base_size, type);
2122 if (!base) {
2124 * We're probably in deep shit, but let's try to fetch
2125 * the required base anyway from another pack or loose.
2126 * This is costly but should happen only in the presence
2127 * of a corrupted pack, and is better than failing outright.
2129 struct revindex_entry *revidx;
2130 const unsigned char *base_sha1;
2131 revidx = find_pack_revindex(p, obj_offset);
2132 if (revidx) {
2133 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
2134 error("failed to read delta base object %s"
2135 " at offset %"PRIuMAX" from %s",
2136 sha1_to_hex(base_sha1), (uintmax_t)obj_offset,
2137 p->pack_name);
2138 mark_bad_packed_object(p, base_sha1);
2139 base = read_object(base_sha1, &type, &base_size);
2143 i = --delta_stack_nr;
2144 obj_offset = delta_stack[i].obj_offset;
2145 curpos = delta_stack[i].curpos;
2146 delta_size = delta_stack[i].size;
2148 if (!base)
2149 continue;
2151 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
2153 if (!delta_data) {
2154 error("failed to unpack compressed delta "
2155 "at offset %"PRIuMAX" from %s",
2156 (uintmax_t)curpos, p->pack_name);
2157 data = NULL;
2158 continue;
2161 data = patch_delta(base, base_size,
2162 delta_data, delta_size,
2163 &size);
2164 if (!data)
2165 die("failed to apply delta");
2167 free (delta_data);
2170 *final_type = type;
2171 *final_size = size;
2173 unuse_pack(&w_curs);
2174 return data;
2177 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
2178 uint32_t n)
2180 const unsigned char *index = p->index_data;
2181 if (!index) {
2182 if (open_pack_index(p))
2183 return NULL;
2184 index = p->index_data;
2186 if (n >= p->num_objects)
2187 return NULL;
2188 index += 4 * 256;
2189 if (p->index_version == 1) {
2190 return index + 24 * n + 4;
2191 } else {
2192 index += 8;
2193 return index + 20 * n;
2197 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
2199 const unsigned char *index = p->index_data;
2200 index += 4 * 256;
2201 if (p->index_version == 1) {
2202 return ntohl(*((uint32_t *)(index + 24 * n)));
2203 } else {
2204 uint32_t off;
2205 index += 8 + p->num_objects * (20 + 4);
2206 off = ntohl(*((uint32_t *)(index + 4 * n)));
2207 if (!(off & 0x80000000))
2208 return off;
2209 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
2210 return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
2211 ntohl(*((uint32_t *)(index + 4)));
2215 off_t find_pack_entry_one(const unsigned char *sha1,
2216 struct packed_git *p)
2218 const uint32_t *level1_ofs = p->index_data;
2219 const unsigned char *index = p->index_data;
2220 unsigned hi, lo, stride;
2221 static int use_lookup = -1;
2222 static int debug_lookup = -1;
2224 if (debug_lookup < 0)
2225 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
2227 if (!index) {
2228 if (open_pack_index(p))
2229 return 0;
2230 level1_ofs = p->index_data;
2231 index = p->index_data;
2233 if (p->index_version > 1) {
2234 level1_ofs += 2;
2235 index += 8;
2237 index += 4 * 256;
2238 hi = ntohl(level1_ofs[*sha1]);
2239 lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
2240 if (p->index_version > 1) {
2241 stride = 20;
2242 } else {
2243 stride = 24;
2244 index += 4;
2247 if (debug_lookup)
2248 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
2249 sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
2251 if (use_lookup < 0)
2252 use_lookup = !!getenv("GIT_USE_LOOKUP");
2253 if (use_lookup) {
2254 int pos = sha1_entry_pos(index, stride, 0,
2255 lo, hi, p->num_objects, sha1);
2256 if (pos < 0)
2257 return 0;
2258 return nth_packed_object_offset(p, pos);
2261 do {
2262 unsigned mi = (lo + hi) / 2;
2263 int cmp = hashcmp(index + mi * stride, sha1);
2265 if (debug_lookup)
2266 printf("lo %u hi %u rg %u mi %u\n",
2267 lo, hi, hi - lo, mi);
2268 if (!cmp)
2269 return nth_packed_object_offset(p, mi);
2270 if (cmp > 0)
2271 hi = mi;
2272 else
2273 lo = mi+1;
2274 } while (lo < hi);
2275 return 0;
2278 int is_pack_valid(struct packed_git *p)
2280 /* An already open pack is known to be valid. */
2281 if (p->pack_fd != -1)
2282 return 1;
2284 /* If the pack has one window completely covering the
2285 * file size, the pack is known to be valid even if
2286 * the descriptor is not currently open.
2288 if (p->windows) {
2289 struct pack_window *w = p->windows;
2291 if (!w->offset && w->len == p->pack_size)
2292 return 1;
2295 /* Force the pack to open to prove its valid. */
2296 return !open_packed_git(p);
2299 static int fill_pack_entry(const unsigned char *sha1,
2300 struct pack_entry *e,
2301 struct packed_git *p)
2303 off_t offset;
2305 if (p->num_bad_objects) {
2306 unsigned i;
2307 for (i = 0; i < p->num_bad_objects; i++)
2308 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
2309 return 0;
2312 offset = find_pack_entry_one(sha1, p);
2313 if (!offset)
2314 return 0;
2317 * We are about to tell the caller where they can locate the
2318 * requested object. We better make sure the packfile is
2319 * still here and can be accessed before supplying that
2320 * answer, as it may have been deleted since the index was
2321 * loaded!
2323 if (!is_pack_valid(p)) {
2324 warning("packfile %s cannot be accessed", p->pack_name);
2325 return 0;
2327 e->offset = offset;
2328 e->p = p;
2329 hashcpy(e->sha1, sha1);
2330 return 1;
2333 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
2335 struct packed_git *p;
2337 prepare_packed_git();
2338 if (!packed_git)
2339 return 0;
2341 if (last_found_pack && fill_pack_entry(sha1, e, last_found_pack))
2342 return 1;
2344 for (p = packed_git; p; p = p->next) {
2345 if (p == last_found_pack || !fill_pack_entry(sha1, e, p))
2346 continue;
2348 last_found_pack = p;
2349 return 1;
2351 return 0;
2354 struct packed_git *find_sha1_pack(const unsigned char *sha1,
2355 struct packed_git *packs)
2357 struct packed_git *p;
2359 for (p = packs; p; p = p->next) {
2360 if (find_pack_entry_one(sha1, p))
2361 return p;
2363 return NULL;
2367 static int sha1_loose_object_info(const unsigned char *sha1,
2368 enum object_type *typep,
2369 unsigned long *sizep,
2370 unsigned long *disk_sizep)
2372 int status;
2373 unsigned long mapsize, size;
2374 void *map;
2375 git_zstream stream;
2376 char hdr[32];
2379 * If we don't care about type or size, then we don't
2380 * need to look inside the object at all.
2382 if (!typep && !sizep) {
2383 if (disk_sizep) {
2384 struct stat st;
2385 if (stat_sha1_file(sha1, &st) < 0)
2386 return -1;
2387 *disk_sizep = st.st_size;
2389 return 0;
2392 map = map_sha1_file(sha1, &mapsize);
2393 if (!map)
2394 return error("unable to find %s", sha1_to_hex(sha1));
2395 if (disk_sizep)
2396 *disk_sizep = mapsize;
2397 if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2398 status = error("unable to unpack %s header",
2399 sha1_to_hex(sha1));
2400 else if ((status = parse_sha1_header(hdr, &size)) < 0)
2401 status = error("unable to parse %s header", sha1_to_hex(sha1));
2402 else if (sizep)
2403 *sizep = size;
2404 git_inflate_end(&stream);
2405 munmap(map, mapsize);
2406 if (typep)
2407 *typep = status;
2408 return 0;
2411 /* returns enum object_type or negative */
2412 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
2414 struct cached_object *co;
2415 struct pack_entry e;
2416 int type, rtype;
2418 co = find_cached_object(sha1);
2419 if (co) {
2420 if (oi->sizep)
2421 *(oi->sizep) = co->size;
2422 if (oi->disk_sizep)
2423 *(oi->disk_sizep) = 0;
2424 oi->whence = OI_CACHED;
2425 return co->type;
2428 if (!find_pack_entry(sha1, &e)) {
2429 /* Most likely it's a loose object. */
2430 if (!sha1_loose_object_info(sha1, &type,
2431 oi->sizep, oi->disk_sizep)) {
2432 oi->whence = OI_LOOSE;
2433 return type;
2436 /* Not a loose object; someone else may have just packed it. */
2437 reprepare_packed_git();
2438 if (!find_pack_entry(sha1, &e))
2439 return -1;
2442 type = packed_object_info(e.p, e.offset, oi->sizep, &rtype,
2443 oi->disk_sizep);
2444 if (type < 0) {
2445 mark_bad_packed_object(e.p, sha1);
2446 type = sha1_object_info_extended(sha1, oi);
2447 } else if (in_delta_base_cache(e.p, e.offset)) {
2448 oi->whence = OI_DBCACHED;
2449 } else {
2450 oi->whence = OI_PACKED;
2451 oi->u.packed.offset = e.offset;
2452 oi->u.packed.pack = e.p;
2453 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
2454 rtype == OBJ_OFS_DELTA);
2457 return type;
2460 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2462 struct object_info oi = {0};
2464 oi.sizep = sizep;
2465 return sha1_object_info_extended(sha1, &oi);
2468 static void *read_packed_sha1(const unsigned char *sha1,
2469 enum object_type *type, unsigned long *size)
2471 struct pack_entry e;
2472 void *data;
2474 if (!find_pack_entry(sha1, &e))
2475 return NULL;
2476 data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
2477 if (!data) {
2479 * We're probably in deep shit, but let's try to fetch
2480 * the required object anyway from another pack or loose.
2481 * This should happen only in the presence of a corrupted
2482 * pack, and is better than failing outright.
2484 error("failed to read object %s at offset %"PRIuMAX" from %s",
2485 sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2486 mark_bad_packed_object(e.p, sha1);
2487 data = read_object(sha1, type, size);
2489 return data;
2492 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2493 unsigned char *sha1)
2495 struct cached_object *co;
2497 hash_sha1_file(buf, len, typename(type), sha1);
2498 if (has_sha1_file(sha1) || find_cached_object(sha1))
2499 return 0;
2500 if (cached_object_alloc <= cached_object_nr) {
2501 cached_object_alloc = alloc_nr(cached_object_alloc);
2502 cached_objects = xrealloc(cached_objects,
2503 sizeof(*cached_objects) *
2504 cached_object_alloc);
2506 co = &cached_objects[cached_object_nr++];
2507 co->size = len;
2508 co->type = type;
2509 co->buf = xmalloc(len);
2510 memcpy(co->buf, buf, len);
2511 hashcpy(co->sha1, sha1);
2512 return 0;
2515 static void *read_object(const unsigned char *sha1, enum object_type *type,
2516 unsigned long *size)
2518 unsigned long mapsize;
2519 void *map, *buf;
2520 struct cached_object *co;
2522 co = find_cached_object(sha1);
2523 if (co) {
2524 *type = co->type;
2525 *size = co->size;
2526 return xmemdupz(co->buf, co->size);
2529 buf = read_packed_sha1(sha1, type, size);
2530 if (buf)
2531 return buf;
2532 map = map_sha1_file(sha1, &mapsize);
2533 if (map) {
2534 buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2535 munmap(map, mapsize);
2536 return buf;
2538 reprepare_packed_git();
2539 return read_packed_sha1(sha1, type, size);
2543 * This function dies on corrupt objects; the callers who want to
2544 * deal with them should arrange to call read_object() and give error
2545 * messages themselves.
2547 void *read_sha1_file_extended(const unsigned char *sha1,
2548 enum object_type *type,
2549 unsigned long *size,
2550 unsigned flag)
2552 void *data;
2553 char *path;
2554 const struct packed_git *p;
2555 const unsigned char *repl = (flag & READ_SHA1_FILE_REPLACE)
2556 ? lookup_replace_object(sha1) : sha1;
2558 errno = 0;
2559 data = read_object(repl, type, size);
2560 if (data)
2561 return data;
2563 if (errno && errno != ENOENT)
2564 die_errno("failed to read object %s", sha1_to_hex(sha1));
2566 /* die if we replaced an object with one that does not exist */
2567 if (repl != sha1)
2568 die("replacement %s not found for %s",
2569 sha1_to_hex(repl), sha1_to_hex(sha1));
2571 if (has_loose_object(repl)) {
2572 path = sha1_file_name(sha1);
2573 die("loose object %s (stored in %s) is corrupt",
2574 sha1_to_hex(repl), path);
2577 if ((p = has_packed_and_bad(repl)) != NULL)
2578 die("packed object %s (stored in %s) is corrupt",
2579 sha1_to_hex(repl), p->pack_name);
2581 return NULL;
2584 void *read_object_with_reference(const unsigned char *sha1,
2585 const char *required_type_name,
2586 unsigned long *size,
2587 unsigned char *actual_sha1_return)
2589 enum object_type type, required_type;
2590 void *buffer;
2591 unsigned long isize;
2592 unsigned char actual_sha1[20];
2594 required_type = type_from_string(required_type_name);
2595 hashcpy(actual_sha1, sha1);
2596 while (1) {
2597 int ref_length = -1;
2598 const char *ref_type = NULL;
2600 buffer = read_sha1_file(actual_sha1, &type, &isize);
2601 if (!buffer)
2602 return NULL;
2603 if (type == required_type) {
2604 *size = isize;
2605 if (actual_sha1_return)
2606 hashcpy(actual_sha1_return, actual_sha1);
2607 return buffer;
2609 /* Handle references */
2610 else if (type == OBJ_COMMIT)
2611 ref_type = "tree ";
2612 else if (type == OBJ_TAG)
2613 ref_type = "object ";
2614 else {
2615 free(buffer);
2616 return NULL;
2618 ref_length = strlen(ref_type);
2620 if (ref_length + 40 > isize ||
2621 memcmp(buffer, ref_type, ref_length) ||
2622 get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2623 free(buffer);
2624 return NULL;
2626 free(buffer);
2627 /* Now we have the ID of the referred-to object in
2628 * actual_sha1. Check again. */
2632 static void write_sha1_file_prepare(const void *buf, unsigned long len,
2633 const char *type, unsigned char *sha1,
2634 char *hdr, int *hdrlen)
2636 git_SHA_CTX c;
2638 /* Generate the header */
2639 *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
2641 /* Sha1.. */
2642 git_SHA1_Init(&c);
2643 git_SHA1_Update(&c, hdr, *hdrlen);
2644 git_SHA1_Update(&c, buf, len);
2645 git_SHA1_Final(sha1, &c);
2649 * Move the just written object into its final resting place.
2650 * NEEDSWORK: this should be renamed to finalize_temp_file() as
2651 * "moving" is only a part of what it does, when no patch between
2652 * master to pu changes the call sites of this function.
2654 int move_temp_to_file(const char *tmpfile, const char *filename)
2656 int ret = 0;
2658 if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2659 goto try_rename;
2660 else if (link(tmpfile, filename))
2661 ret = errno;
2664 * Coda hack - coda doesn't like cross-directory links,
2665 * so we fall back to a rename, which will mean that it
2666 * won't be able to check collisions, but that's not a
2667 * big deal.
2669 * The same holds for FAT formatted media.
2671 * When this succeeds, we just return. We have nothing
2672 * left to unlink.
2674 if (ret && ret != EEXIST) {
2675 try_rename:
2676 if (!rename(tmpfile, filename))
2677 goto out;
2678 ret = errno;
2680 unlink_or_warn(tmpfile);
2681 if (ret) {
2682 if (ret != EEXIST) {
2683 return error("unable to write sha1 filename %s: %s", filename, strerror(ret));
2685 /* FIXME!!! Collision check here ? */
2688 out:
2689 if (adjust_shared_perm(filename))
2690 return error("unable to set permission to '%s'", filename);
2691 return 0;
2694 static int write_buffer(int fd, const void *buf, size_t len)
2696 if (write_in_full(fd, buf, len) < 0)
2697 return error("file write error (%s)", strerror(errno));
2698 return 0;
2701 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2702 unsigned char *sha1)
2704 char hdr[32];
2705 int hdrlen;
2706 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2707 return 0;
2710 /* Finalize a file on disk, and close it. */
2711 static void close_sha1_file(int fd)
2713 if (fsync_object_files)
2714 fsync_or_die(fd, "sha1 file");
2715 if (close(fd) != 0)
2716 die_errno("error when closing sha1 file");
2719 /* Size of directory component, including the ending '/' */
2720 static inline int directory_size(const char *filename)
2722 const char *s = strrchr(filename, '/');
2723 if (!s)
2724 return 0;
2725 return s - filename + 1;
2729 * This creates a temporary file in the same directory as the final
2730 * 'filename'
2732 * We want to avoid cross-directory filename renames, because those
2733 * can have problems on various filesystems (FAT, NFS, Coda).
2735 static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
2737 int fd, dirlen = directory_size(filename);
2739 if (dirlen + 20 > bufsiz) {
2740 errno = ENAMETOOLONG;
2741 return -1;
2743 memcpy(buffer, filename, dirlen);
2744 strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
2745 fd = git_mkstemp_mode(buffer, 0444);
2746 if (fd < 0 && dirlen && errno == ENOENT) {
2747 /* Make sure the directory exists */
2748 memcpy(buffer, filename, dirlen);
2749 buffer[dirlen-1] = 0;
2750 if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
2751 return -1;
2753 /* Try again */
2754 strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
2755 fd = git_mkstemp_mode(buffer, 0444);
2757 return fd;
2760 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
2761 const void *buf, unsigned long len, time_t mtime)
2763 int fd, ret;
2764 unsigned char compressed[4096];
2765 git_zstream stream;
2766 git_SHA_CTX c;
2767 unsigned char parano_sha1[20];
2768 char *filename;
2769 static char tmp_file[PATH_MAX];
2771 filename = sha1_file_name(sha1);
2772 fd = create_tmpfile(tmp_file, sizeof(tmp_file), filename);
2773 if (fd < 0) {
2774 if (errno == EACCES)
2775 return error("insufficient permission for adding an object to repository database %s", get_object_directory());
2776 else
2777 return error("unable to create temporary file: %s", strerror(errno));
2780 /* Set it up */
2781 memset(&stream, 0, sizeof(stream));
2782 git_deflate_init(&stream, zlib_compression_level);
2783 stream.next_out = compressed;
2784 stream.avail_out = sizeof(compressed);
2785 git_SHA1_Init(&c);
2787 /* First header.. */
2788 stream.next_in = (unsigned char *)hdr;
2789 stream.avail_in = hdrlen;
2790 while (git_deflate(&stream, 0) == Z_OK)
2791 ; /* nothing */
2792 git_SHA1_Update(&c, hdr, hdrlen);
2794 /* Then the data itself.. */
2795 stream.next_in = (void *)buf;
2796 stream.avail_in = len;
2797 do {
2798 unsigned char *in0 = stream.next_in;
2799 ret = git_deflate(&stream, Z_FINISH);
2800 git_SHA1_Update(&c, in0, stream.next_in - in0);
2801 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
2802 die("unable to write sha1 file");
2803 stream.next_out = compressed;
2804 stream.avail_out = sizeof(compressed);
2805 } while (ret == Z_OK);
2807 if (ret != Z_STREAM_END)
2808 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
2809 ret = git_deflate_end_gently(&stream);
2810 if (ret != Z_OK)
2811 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
2812 git_SHA1_Final(parano_sha1, &c);
2813 if (hashcmp(sha1, parano_sha1) != 0)
2814 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
2816 close_sha1_file(fd);
2818 if (mtime) {
2819 struct utimbuf utb;
2820 utb.actime = mtime;
2821 utb.modtime = mtime;
2822 if (utime(tmp_file, &utb) < 0)
2823 warning("failed utime() on %s: %s",
2824 tmp_file, strerror(errno));
2827 return move_temp_to_file(tmp_file, filename);
2830 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
2832 unsigned char sha1[20];
2833 char hdr[32];
2834 int hdrlen;
2836 /* Normally if we have it in the pack then we do not bother writing
2837 * it out into .git/objects/??/?{38} file.
2839 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2840 if (returnsha1)
2841 hashcpy(returnsha1, sha1);
2842 if (has_sha1_file(sha1))
2843 return 0;
2844 return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
2847 int force_object_loose(const unsigned char *sha1, time_t mtime)
2849 void *buf;
2850 unsigned long len;
2851 enum object_type type;
2852 char hdr[32];
2853 int hdrlen;
2854 int ret;
2856 if (has_loose_object(sha1))
2857 return 0;
2858 buf = read_packed_sha1(sha1, &type, &len);
2859 if (!buf)
2860 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
2861 hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
2862 ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
2863 free(buf);
2865 return ret;
2868 int has_pack_index(const unsigned char *sha1)
2870 struct stat st;
2871 if (stat(sha1_pack_index_name(sha1), &st))
2872 return 0;
2873 return 1;
2876 int has_sha1_pack(const unsigned char *sha1)
2878 struct pack_entry e;
2879 return find_pack_entry(sha1, &e);
2882 int has_sha1_file(const unsigned char *sha1)
2884 struct pack_entry e;
2886 if (find_pack_entry(sha1, &e))
2887 return 1;
2888 return has_loose_object(sha1);
2891 static void check_tree(const void *buf, size_t size)
2893 struct tree_desc desc;
2894 struct name_entry entry;
2896 init_tree_desc(&desc, buf, size);
2897 while (tree_entry(&desc, &entry))
2898 /* do nothing
2899 * tree_entry() will die() on malformed entries */
2903 static void check_commit(const void *buf, size_t size)
2905 struct commit c;
2906 memset(&c, 0, sizeof(c));
2907 if (parse_commit_buffer(&c, buf, size))
2908 die("corrupt commit");
2911 static void check_tag(const void *buf, size_t size)
2913 struct tag t;
2914 memset(&t, 0, sizeof(t));
2915 if (parse_tag_buffer(&t, buf, size))
2916 die("corrupt tag");
2919 static int index_mem(unsigned char *sha1, void *buf, size_t size,
2920 enum object_type type,
2921 const char *path, unsigned flags)
2923 int ret, re_allocated = 0;
2924 int write_object = flags & HASH_WRITE_OBJECT;
2926 if (!type)
2927 type = OBJ_BLOB;
2930 * Convert blobs to git internal format
2932 if ((type == OBJ_BLOB) && path) {
2933 struct strbuf nbuf = STRBUF_INIT;
2934 if (convert_to_git(path, buf, size, &nbuf,
2935 write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
2936 buf = strbuf_detach(&nbuf, &size);
2937 re_allocated = 1;
2940 if (flags & HASH_FORMAT_CHECK) {
2941 if (type == OBJ_TREE)
2942 check_tree(buf, size);
2943 if (type == OBJ_COMMIT)
2944 check_commit(buf, size);
2945 if (type == OBJ_TAG)
2946 check_tag(buf, size);
2949 if (write_object)
2950 ret = write_sha1_file(buf, size, typename(type), sha1);
2951 else
2952 ret = hash_sha1_file(buf, size, typename(type), sha1);
2953 if (re_allocated)
2954 free(buf);
2955 return ret;
2958 static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
2959 const char *path, unsigned flags)
2961 struct strbuf sbuf = STRBUF_INIT;
2962 int ret;
2964 if (strbuf_read(&sbuf, fd, 4096) >= 0)
2965 ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
2966 else
2967 ret = -1;
2968 strbuf_release(&sbuf);
2969 return ret;
2972 #define SMALL_FILE_SIZE (32*1024)
2974 static int index_core(unsigned char *sha1, int fd, size_t size,
2975 enum object_type type, const char *path,
2976 unsigned flags)
2978 int ret;
2980 if (!size) {
2981 ret = index_mem(sha1, NULL, size, type, path, flags);
2982 } else if (size <= SMALL_FILE_SIZE) {
2983 char *buf = xmalloc(size);
2984 if (size == read_in_full(fd, buf, size))
2985 ret = index_mem(sha1, buf, size, type, path, flags);
2986 else
2987 ret = error("short read %s", strerror(errno));
2988 free(buf);
2989 } else {
2990 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2991 ret = index_mem(sha1, buf, size, type, path, flags);
2992 munmap(buf, size);
2994 return ret;
2998 * This creates one packfile per large blob unless bulk-checkin
2999 * machinery is "plugged".
3001 * This also bypasses the usual "convert-to-git" dance, and that is on
3002 * purpose. We could write a streaming version of the converting
3003 * functions and insert that before feeding the data to fast-import
3004 * (or equivalent in-core API described above). However, that is
3005 * somewhat complicated, as we do not know the size of the filter
3006 * result, which we need to know beforehand when writing a git object.
3007 * Since the primary motivation for trying to stream from the working
3008 * tree file and to avoid mmaping it in core is to deal with large
3009 * binary blobs, they generally do not want to get any conversion, and
3010 * callers should avoid this code path when filters are requested.
3012 static int index_stream(unsigned char *sha1, int fd, size_t size,
3013 enum object_type type, const char *path,
3014 unsigned flags)
3016 return index_bulk_checkin(sha1, fd, size, type, path, flags);
3019 int index_fd(unsigned char *sha1, int fd, struct stat *st,
3020 enum object_type type, const char *path, unsigned flags)
3022 int ret;
3023 size_t size = xsize_t(st->st_size);
3025 if (!S_ISREG(st->st_mode))
3026 ret = index_pipe(sha1, fd, type, path, flags);
3027 else if (size <= big_file_threshold || type != OBJ_BLOB ||
3028 (path && would_convert_to_git(path, NULL, 0, 0)))
3029 ret = index_core(sha1, fd, size, type, path, flags);
3030 else
3031 ret = index_stream(sha1, fd, size, type, path, flags);
3032 close(fd);
3033 return ret;
3036 int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
3038 int fd;
3039 struct strbuf sb = STRBUF_INIT;
3041 switch (st->st_mode & S_IFMT) {
3042 case S_IFREG:
3043 fd = open(path, O_RDONLY);
3044 if (fd < 0)
3045 return error("open(\"%s\"): %s", path,
3046 strerror(errno));
3047 if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
3048 return error("%s: failed to insert into database",
3049 path);
3050 break;
3051 case S_IFLNK:
3052 if (strbuf_readlink(&sb, path, st->st_size)) {
3053 char *errstr = strerror(errno);
3054 return error("readlink(\"%s\"): %s", path,
3055 errstr);
3057 if (!(flags & HASH_WRITE_OBJECT))
3058 hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
3059 else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
3060 return error("%s: failed to insert into database",
3061 path);
3062 strbuf_release(&sb);
3063 break;
3064 case S_IFDIR:
3065 return resolve_gitlink_ref(path, "HEAD", sha1);
3066 default:
3067 return error("%s: unsupported file type", path);
3069 return 0;
3072 int read_pack_header(int fd, struct pack_header *header)
3074 if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
3075 /* "eof before pack header was fully read" */
3076 return PH_ERROR_EOF;
3078 if (header->hdr_signature != htonl(PACK_SIGNATURE))
3079 /* "protocol error (pack signature mismatch detected)" */
3080 return PH_ERROR_PACK_SIGNATURE;
3081 if (!pack_version_ok(header->hdr_version))
3082 /* "protocol error (pack version unsupported)" */
3083 return PH_ERROR_PROTOCOL;
3084 return 0;
3087 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
3089 enum object_type type = sha1_object_info(sha1, NULL);
3090 if (type < 0)
3091 die("%s is not a valid object", sha1_to_hex(sha1));
3092 if (type != expect)
3093 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
3094 typename(expect));