Merge branch 'rc/histogram-diff' into HEAD
[git/jrn.git] / sha1_file.c
blobd5616dca0809bdb9fd6a7a1980b92ded9ae6e230
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 "delta.h"
11 #include "pack.h"
12 #include "blob.h"
13 #include "commit.h"
14 #include "run-command.h"
15 #include "tag.h"
16 #include "tree.h"
17 #include "tree-walk.h"
18 #include "refs.h"
19 #include "pack-revindex.h"
20 #include "sha1-lookup.h"
22 #ifndef O_NOATIME
23 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
24 #define O_NOATIME 01000000
25 #else
26 #define O_NOATIME 0
27 #endif
28 #endif
30 #define SZ_FMT PRIuMAX
31 static inline uintmax_t sz_fmt(size_t s) { return s; }
33 const unsigned char null_sha1[20];
36 * This is meant to hold a *small* number of objects that you would
37 * want read_sha1_file() to be able to return, but yet you do not want
38 * to write them into the object store (e.g. a browse-only
39 * application).
41 static struct cached_object {
42 unsigned char sha1[20];
43 enum object_type type;
44 void *buf;
45 unsigned long size;
46 } *cached_objects;
47 static int cached_object_nr, cached_object_alloc;
49 static struct cached_object empty_tree = {
50 EMPTY_TREE_SHA1_BIN_LITERAL,
51 OBJ_TREE,
52 "",
56 static struct cached_object *find_cached_object(const unsigned char *sha1)
58 int i;
59 struct cached_object *co = cached_objects;
61 for (i = 0; i < cached_object_nr; i++, co++) {
62 if (!hashcmp(co->sha1, sha1))
63 return co;
65 if (!hashcmp(sha1, empty_tree.sha1))
66 return &empty_tree;
67 return NULL;
70 int mkdir_in_gitdir(const char *path)
72 if (mkdir(path, 0777)) {
73 int saved_errno = errno;
74 struct stat st;
75 struct strbuf sb = STRBUF_INIT;
77 if (errno != EEXIST)
78 return -1;
80 * Are we looking at a path in a symlinked worktree
81 * whose original repository does not yet have it?
82 * e.g. .git/rr-cache pointing at its original
83 * repository in which the user hasn't performed any
84 * conflict resolution yet?
86 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
87 strbuf_readlink(&sb, path, st.st_size) ||
88 !is_absolute_path(sb.buf) ||
89 mkdir(sb.buf, 0777)) {
90 strbuf_release(&sb);
91 errno = saved_errno;
92 return -1;
94 strbuf_release(&sb);
96 return adjust_shared_perm(path);
99 int safe_create_leading_directories(char *path)
101 char *pos = path + offset_1st_component(path);
102 struct stat st;
104 while (pos) {
105 pos = strchr(pos, '/');
106 if (!pos)
107 break;
108 while (*++pos == '/')
110 if (!*pos)
111 break;
112 *--pos = '\0';
113 if (!stat(path, &st)) {
114 /* path exists */
115 if (!S_ISDIR(st.st_mode)) {
116 *pos = '/';
117 return -3;
120 else if (mkdir(path, 0777)) {
121 *pos = '/';
122 return -1;
124 else if (adjust_shared_perm(path)) {
125 *pos = '/';
126 return -2;
128 *pos++ = '/';
130 return 0;
133 int safe_create_leading_directories_const(const char *path)
135 /* path points to cache entries, so xstrdup before messing with it */
136 char *buf = xstrdup(path);
137 int result = safe_create_leading_directories(buf);
138 free(buf);
139 return result;
142 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
144 int i;
145 for (i = 0; i < 20; i++) {
146 static char hex[] = "0123456789abcdef";
147 unsigned int val = sha1[i];
148 char *pos = pathbuf + i*2 + (i > 0);
149 *pos++ = hex[val >> 4];
150 *pos = hex[val & 0xf];
155 * NOTE! This returns a statically allocated buffer, so you have to be
156 * careful about using it. Do an "xstrdup()" if you need to save the
157 * filename.
159 * Also note that this returns the location for creating. Reading
160 * SHA1 file can happen from any alternate directory listed in the
161 * DB_ENVIRONMENT environment variable if it is not found in
162 * the primary object database.
164 char *sha1_file_name(const unsigned char *sha1)
166 static char buf[PATH_MAX];
167 const char *objdir;
168 int len;
170 objdir = get_object_directory();
171 len = strlen(objdir);
173 /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
174 if (len + 43 > PATH_MAX)
175 die("insanely long object directory %s", objdir);
176 memcpy(buf, objdir, len);
177 buf[len] = '/';
178 buf[len+3] = '/';
179 buf[len+42] = '\0';
180 fill_sha1_path(buf + len + 1, sha1);
181 return buf;
184 static char *sha1_get_pack_name(const unsigned char *sha1,
185 char **name, char **base, const char *which)
187 static const char hex[] = "0123456789abcdef";
188 char *buf;
189 int i;
191 if (!*base) {
192 const char *sha1_file_directory = get_object_directory();
193 int len = strlen(sha1_file_directory);
194 *base = xmalloc(len + 60);
195 sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
196 sha1_file_directory, which);
197 *name = *base + len + 11;
200 buf = *name;
202 for (i = 0; i < 20; i++) {
203 unsigned int val = *sha1++;
204 *buf++ = hex[val >> 4];
205 *buf++ = hex[val & 0xf];
208 return *base;
211 char *sha1_pack_name(const unsigned char *sha1)
213 static char *name, *base;
215 return sha1_get_pack_name(sha1, &name, &base, "pack");
218 char *sha1_pack_index_name(const unsigned char *sha1)
220 static char *name, *base;
222 return sha1_get_pack_name(sha1, &name, &base, "idx");
225 struct alternate_object_database *alt_odb_list;
226 static struct alternate_object_database **alt_odb_tail;
228 static void read_info_alternates(const char * alternates, int depth);
229 static int git_open_noatime(const char *name);
232 * Prepare alternate object database registry.
234 * The variable alt_odb_list points at the list of struct
235 * alternate_object_database. The elements on this list come from
236 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
237 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
238 * whose contents is similar to that environment variable but can be
239 * LF separated. Its base points at a statically allocated buffer that
240 * contains "/the/directory/corresponding/to/.git/objects/...", while
241 * its name points just after the slash at the end of ".git/objects/"
242 * in the example above, and has enough space to hold 40-byte hex
243 * SHA1, an extra slash for the first level indirection, and the
244 * terminating NUL.
246 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
248 const char *objdir = get_object_directory();
249 struct alternate_object_database *ent;
250 struct alternate_object_database *alt;
251 /* 43 = 40-byte + 2 '/' + terminating NUL */
252 int pfxlen = len;
253 int entlen = pfxlen + 43;
254 int base_len = -1;
256 if (!is_absolute_path(entry) && relative_base) {
257 /* Relative alt-odb */
258 if (base_len < 0)
259 base_len = strlen(relative_base) + 1;
260 entlen += base_len;
261 pfxlen += base_len;
263 ent = xmalloc(sizeof(*ent) + entlen);
265 if (!is_absolute_path(entry) && relative_base) {
266 memcpy(ent->base, relative_base, base_len - 1);
267 ent->base[base_len - 1] = '/';
268 memcpy(ent->base + base_len, entry, len);
270 else
271 memcpy(ent->base, entry, pfxlen);
273 ent->name = ent->base + pfxlen + 1;
274 ent->base[pfxlen + 3] = '/';
275 ent->base[pfxlen] = ent->base[entlen-1] = 0;
277 /* Detect cases where alternate disappeared */
278 if (!is_directory(ent->base)) {
279 error("object directory %s does not exist; "
280 "check .git/objects/info/alternates.",
281 ent->base);
282 free(ent);
283 return -1;
286 /* Prevent the common mistake of listing the same
287 * thing twice, or object directory itself.
289 for (alt = alt_odb_list; alt; alt = alt->next) {
290 if (!memcmp(ent->base, alt->base, pfxlen)) {
291 free(ent);
292 return -1;
295 if (!memcmp(ent->base, objdir, pfxlen)) {
296 free(ent);
297 return -1;
300 /* add the alternate entry */
301 *alt_odb_tail = ent;
302 alt_odb_tail = &(ent->next);
303 ent->next = NULL;
305 /* recursively add alternates */
306 read_info_alternates(ent->base, depth + 1);
308 ent->base[pfxlen] = '/';
310 return 0;
313 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
314 const char *relative_base, int depth)
316 const char *cp, *last;
318 if (depth > 5) {
319 error("%s: ignoring alternate object stores, nesting too deep.",
320 relative_base);
321 return;
324 last = alt;
325 while (last < ep) {
326 cp = last;
327 if (cp < ep && *cp == '#') {
328 while (cp < ep && *cp != sep)
329 cp++;
330 last = cp + 1;
331 continue;
333 while (cp < ep && *cp != sep)
334 cp++;
335 if (last != cp) {
336 if (!is_absolute_path(last) && depth) {
337 error("%s: ignoring relative alternate object store %s",
338 relative_base, last);
339 } else {
340 link_alt_odb_entry(last, cp - last,
341 relative_base, depth);
344 while (cp < ep && *cp == sep)
345 cp++;
346 last = cp;
350 static void read_info_alternates(const char * relative_base, int depth)
352 char *map;
353 size_t mapsz;
354 struct stat st;
355 const char alt_file_name[] = "info/alternates";
356 /* Given that relative_base is no longer than PATH_MAX,
357 ensure that "path" has enough space to append "/", the
358 file name, "info/alternates", and a trailing NUL. */
359 char path[PATH_MAX + 1 + sizeof alt_file_name];
360 int fd;
362 sprintf(path, "%s/%s", relative_base, alt_file_name);
363 fd = git_open_noatime(path);
364 if (fd < 0)
365 return;
366 if (fstat(fd, &st) || (st.st_size == 0)) {
367 close(fd);
368 return;
370 mapsz = xsize_t(st.st_size);
371 map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
372 close(fd);
374 link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth);
376 munmap(map, mapsz);
379 void add_to_alternates_file(const char *reference)
381 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
382 int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR);
383 char *alt = mkpath("%s/objects\n", reference);
384 write_or_die(fd, alt, strlen(alt));
385 if (commit_lock_file(lock))
386 die("could not close alternates file");
387 if (alt_odb_tail)
388 link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0);
391 void foreach_alt_odb(alt_odb_fn fn, void *cb)
393 struct alternate_object_database *ent;
395 prepare_alt_odb();
396 for (ent = alt_odb_list; ent; ent = ent->next)
397 if (fn(ent, cb))
398 return;
401 void prepare_alt_odb(void)
403 const char *alt;
405 if (alt_odb_tail)
406 return;
408 alt = getenv(ALTERNATE_DB_ENVIRONMENT);
409 if (!alt) alt = "";
411 alt_odb_tail = &alt_odb_list;
412 link_alt_odb_entries(alt, alt + strlen(alt), PATH_SEP, NULL, 0);
414 read_info_alternates(get_object_directory(), 0);
417 static int has_loose_object_local(const unsigned char *sha1)
419 char *name = sha1_file_name(sha1);
420 return !access(name, F_OK);
423 int has_loose_object_nonlocal(const unsigned char *sha1)
425 struct alternate_object_database *alt;
426 prepare_alt_odb();
427 for (alt = alt_odb_list; alt; alt = alt->next) {
428 fill_sha1_path(alt->name, sha1);
429 if (!access(alt->base, F_OK))
430 return 1;
432 return 0;
435 static int has_loose_object(const unsigned char *sha1)
437 return has_loose_object_local(sha1) ||
438 has_loose_object_nonlocal(sha1);
441 static unsigned int pack_used_ctr;
442 static unsigned int pack_mmap_calls;
443 static unsigned int peak_pack_open_windows;
444 static unsigned int pack_open_windows;
445 static unsigned int pack_open_fds;
446 static unsigned int pack_max_fds;
447 static size_t peak_pack_mapped;
448 static size_t pack_mapped;
449 struct packed_git *packed_git;
451 void pack_report(void)
453 fprintf(stderr,
454 "pack_report: getpagesize() = %10" SZ_FMT "\n"
455 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
456 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
457 sz_fmt(getpagesize()),
458 sz_fmt(packed_git_window_size),
459 sz_fmt(packed_git_limit));
460 fprintf(stderr,
461 "pack_report: pack_used_ctr = %10u\n"
462 "pack_report: pack_mmap_calls = %10u\n"
463 "pack_report: pack_open_windows = %10u / %10u\n"
464 "pack_report: pack_mapped = "
465 "%10" SZ_FMT " / %10" SZ_FMT "\n",
466 pack_used_ctr,
467 pack_mmap_calls,
468 pack_open_windows, peak_pack_open_windows,
469 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
472 static int check_packed_git_idx(const char *path, struct packed_git *p)
474 void *idx_map;
475 struct pack_idx_header *hdr;
476 size_t idx_size;
477 uint32_t version, nr, i, *index;
478 int fd = git_open_noatime(path);
479 struct stat st;
481 if (fd < 0)
482 return -1;
483 if (fstat(fd, &st)) {
484 close(fd);
485 return -1;
487 idx_size = xsize_t(st.st_size);
488 if (idx_size < 4 * 256 + 20 + 20) {
489 close(fd);
490 return error("index file %s is too small", path);
492 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
493 close(fd);
495 hdr = idx_map;
496 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
497 version = ntohl(hdr->idx_version);
498 if (version < 2 || version > 2) {
499 munmap(idx_map, idx_size);
500 return error("index file %s is version %"PRIu32
501 " and is not supported by this binary"
502 " (try upgrading GIT to a newer version)",
503 path, version);
505 } else
506 version = 1;
508 nr = 0;
509 index = idx_map;
510 if (version > 1)
511 index += 2; /* skip index header */
512 for (i = 0; i < 256; i++) {
513 uint32_t n = ntohl(index[i]);
514 if (n < nr) {
515 munmap(idx_map, idx_size);
516 return error("non-monotonic index %s", path);
518 nr = n;
521 if (version == 1) {
523 * Total size:
524 * - 256 index entries 4 bytes each
525 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
526 * - 20-byte SHA1 of the packfile
527 * - 20-byte SHA1 file checksum
529 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
530 munmap(idx_map, idx_size);
531 return error("wrong index v1 file size in %s", path);
533 } else if (version == 2) {
535 * Minimum size:
536 * - 8 bytes of header
537 * - 256 index entries 4 bytes each
538 * - 20-byte sha1 entry * nr
539 * - 4-byte crc entry * nr
540 * - 4-byte offset entry * nr
541 * - 20-byte SHA1 of the packfile
542 * - 20-byte SHA1 file checksum
543 * And after the 4-byte offset table might be a
544 * variable sized table containing 8-byte entries
545 * for offsets larger than 2^31.
547 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
548 unsigned long max_size = min_size;
549 if (nr)
550 max_size += (nr - 1)*8;
551 if (idx_size < min_size || idx_size > max_size) {
552 munmap(idx_map, idx_size);
553 return error("wrong index v2 file size in %s", path);
555 if (idx_size != min_size &&
557 * make sure we can deal with large pack offsets.
558 * 31-bit signed offset won't be enough, neither
559 * 32-bit unsigned one will be.
561 (sizeof(off_t) <= 4)) {
562 munmap(idx_map, idx_size);
563 return error("pack too large for current definition of off_t in %s", path);
567 p->index_version = version;
568 p->index_data = idx_map;
569 p->index_size = idx_size;
570 p->num_objects = nr;
571 return 0;
574 int open_pack_index(struct packed_git *p)
576 char *idx_name;
577 int ret;
579 if (p->index_data)
580 return 0;
582 idx_name = xstrdup(p->pack_name);
583 strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
584 ret = check_packed_git_idx(idx_name, p);
585 free(idx_name);
586 return ret;
589 static void scan_windows(struct packed_git *p,
590 struct packed_git **lru_p,
591 struct pack_window **lru_w,
592 struct pack_window **lru_l)
594 struct pack_window *w, *w_l;
596 for (w_l = NULL, w = p->windows; w; w = w->next) {
597 if (!w->inuse_cnt) {
598 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
599 *lru_p = p;
600 *lru_w = w;
601 *lru_l = w_l;
604 w_l = w;
608 static int unuse_one_window(struct packed_git *current, int keep_fd)
610 struct packed_git *p, *lru_p = NULL;
611 struct pack_window *lru_w = NULL, *lru_l = NULL;
613 if (current)
614 scan_windows(current, &lru_p, &lru_w, &lru_l);
615 for (p = packed_git; p; p = p->next)
616 scan_windows(p, &lru_p, &lru_w, &lru_l);
617 if (lru_p) {
618 munmap(lru_w->base, lru_w->len);
619 pack_mapped -= lru_w->len;
620 if (lru_l)
621 lru_l->next = lru_w->next;
622 else {
623 lru_p->windows = lru_w->next;
624 if (!lru_p->windows && lru_p->pack_fd != -1
625 && lru_p->pack_fd != keep_fd) {
626 close(lru_p->pack_fd);
627 pack_open_fds--;
628 lru_p->pack_fd = -1;
631 free(lru_w);
632 pack_open_windows--;
633 return 1;
635 return 0;
638 void release_pack_memory(size_t need, int fd)
640 size_t cur = pack_mapped;
641 while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd))
642 ; /* nothing */
645 void *xmmap(void *start, size_t length,
646 int prot, int flags, int fd, off_t offset)
648 void *ret = mmap(start, length, prot, flags, fd, offset);
649 if (ret == MAP_FAILED) {
650 if (!length)
651 return NULL;
652 release_pack_memory(length, fd);
653 ret = mmap(start, length, prot, flags, fd, offset);
654 if (ret == MAP_FAILED)
655 die_errno("Out of memory? mmap failed");
657 return ret;
660 void close_pack_windows(struct packed_git *p)
662 while (p->windows) {
663 struct pack_window *w = p->windows;
665 if (w->inuse_cnt)
666 die("pack '%s' still has open windows to it",
667 p->pack_name);
668 munmap(w->base, w->len);
669 pack_mapped -= w->len;
670 pack_open_windows--;
671 p->windows = w->next;
672 free(w);
676 void unuse_pack(struct pack_window **w_cursor)
678 struct pack_window *w = *w_cursor;
679 if (w) {
680 w->inuse_cnt--;
681 *w_cursor = NULL;
685 void close_pack_index(struct packed_git *p)
687 if (p->index_data) {
688 munmap((void *)p->index_data, p->index_size);
689 p->index_data = NULL;
694 * This is used by git-repack in case a newly created pack happens to
695 * contain the same set of objects as an existing one. In that case
696 * the resulting file might be different even if its name would be the
697 * same. It is best to close any reference to the old pack before it is
698 * replaced on disk. Of course no index pointers nor windows for given pack
699 * must subsist at this point. If ever objects from this pack are requested
700 * again, the new version of the pack will be reinitialized through
701 * reprepare_packed_git().
703 void free_pack_by_name(const char *pack_name)
705 struct packed_git *p, **pp = &packed_git;
707 while (*pp) {
708 p = *pp;
709 if (strcmp(pack_name, p->pack_name) == 0) {
710 clear_delta_base_cache();
711 close_pack_windows(p);
712 if (p->pack_fd != -1) {
713 close(p->pack_fd);
714 pack_open_fds--;
716 close_pack_index(p);
717 free(p->bad_object_sha1);
718 *pp = p->next;
719 free(p);
720 return;
722 pp = &p->next;
727 * Do not call this directly as this leaks p->pack_fd on error return;
728 * call open_packed_git() instead.
730 static int open_packed_git_1(struct packed_git *p)
732 struct stat st;
733 struct pack_header hdr;
734 unsigned char sha1[20];
735 unsigned char *idx_sha1;
736 long fd_flag;
738 if (!p->index_data && open_pack_index(p))
739 return error("packfile %s index unavailable", p->pack_name);
741 if (!pack_max_fds) {
742 struct rlimit lim;
743 unsigned int max_fds;
745 if (getrlimit(RLIMIT_NOFILE, &lim))
746 die_errno("cannot get RLIMIT_NOFILE");
748 max_fds = lim.rlim_cur;
750 /* Save 3 for stdin/stdout/stderr, 22 for work */
751 if (25 < max_fds)
752 pack_max_fds = max_fds - 25;
753 else
754 pack_max_fds = 1;
757 while (pack_max_fds <= pack_open_fds && unuse_one_window(NULL, -1))
758 ; /* nothing */
760 p->pack_fd = git_open_noatime(p->pack_name);
761 if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
762 return -1;
763 pack_open_fds++;
765 /* If we created the struct before we had the pack we lack size. */
766 if (!p->pack_size) {
767 if (!S_ISREG(st.st_mode))
768 return error("packfile %s not a regular file", p->pack_name);
769 p->pack_size = st.st_size;
770 } else if (p->pack_size != st.st_size)
771 return error("packfile %s size changed", p->pack_name);
773 /* We leave these file descriptors open with sliding mmap;
774 * there is no point keeping them open across exec(), though.
776 fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
777 if (fd_flag < 0)
778 return error("cannot determine file descriptor flags");
779 fd_flag |= FD_CLOEXEC;
780 if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
781 return error("cannot set FD_CLOEXEC");
783 /* Verify we recognize this pack file format. */
784 if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
785 return error("file %s is far too short to be a packfile", p->pack_name);
786 if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
787 return error("file %s is not a GIT packfile", p->pack_name);
788 if (!pack_version_ok(hdr.hdr_version))
789 return error("packfile %s is version %"PRIu32" and not"
790 " supported (try upgrading GIT to a newer version)",
791 p->pack_name, ntohl(hdr.hdr_version));
793 /* Verify the pack matches its index. */
794 if (p->num_objects != ntohl(hdr.hdr_entries))
795 return error("packfile %s claims to have %"PRIu32" objects"
796 " while index indicates %"PRIu32" objects",
797 p->pack_name, ntohl(hdr.hdr_entries),
798 p->num_objects);
799 if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
800 return error("end of packfile %s is unavailable", p->pack_name);
801 if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
802 return error("packfile %s signature is unavailable", p->pack_name);
803 idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
804 if (hashcmp(sha1, idx_sha1))
805 return error("packfile %s does not match index", p->pack_name);
806 return 0;
809 static int open_packed_git(struct packed_git *p)
811 if (!open_packed_git_1(p))
812 return 0;
813 if (p->pack_fd != -1) {
814 close(p->pack_fd);
815 pack_open_fds--;
816 p->pack_fd = -1;
818 return -1;
821 static int in_window(struct pack_window *win, off_t offset)
823 /* We must promise at least 20 bytes (one hash) after the
824 * offset is available from this window, otherwise the offset
825 * is not actually in this window and a different window (which
826 * has that one hash excess) must be used. This is to support
827 * the object header and delta base parsing routines below.
829 off_t win_off = win->offset;
830 return win_off <= offset
831 && (offset + 20) <= (win_off + win->len);
834 unsigned char *use_pack(struct packed_git *p,
835 struct pack_window **w_cursor,
836 off_t offset,
837 unsigned long *left)
839 struct pack_window *win = *w_cursor;
841 /* Since packfiles end in a hash of their content and it's
842 * pointless to ask for an offset into the middle of that
843 * hash, and the in_window function above wouldn't match
844 * don't allow an offset too close to the end of the file.
846 if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
847 die("packfile %s cannot be accessed", p->pack_name);
848 if (offset > (p->pack_size - 20))
849 die("offset beyond end of packfile (truncated pack?)");
851 if (!win || !in_window(win, offset)) {
852 if (win)
853 win->inuse_cnt--;
854 for (win = p->windows; win; win = win->next) {
855 if (in_window(win, offset))
856 break;
858 if (!win) {
859 size_t window_align = packed_git_window_size / 2;
860 off_t len;
862 if (p->pack_fd == -1 && open_packed_git(p))
863 die("packfile %s cannot be accessed", p->pack_name);
865 win = xcalloc(1, sizeof(*win));
866 win->offset = (offset / window_align) * window_align;
867 len = p->pack_size - win->offset;
868 if (len > packed_git_window_size)
869 len = packed_git_window_size;
870 win->len = (size_t)len;
871 pack_mapped += win->len;
872 while (packed_git_limit < pack_mapped
873 && unuse_one_window(p, p->pack_fd))
874 ; /* nothing */
875 win->base = xmmap(NULL, win->len,
876 PROT_READ, MAP_PRIVATE,
877 p->pack_fd, win->offset);
878 if (win->base == MAP_FAILED)
879 die("packfile %s cannot be mapped: %s",
880 p->pack_name,
881 strerror(errno));
882 if (!win->offset && win->len == p->pack_size
883 && !p->do_not_close) {
884 close(p->pack_fd);
885 pack_open_fds--;
886 p->pack_fd = -1;
888 pack_mmap_calls++;
889 pack_open_windows++;
890 if (pack_mapped > peak_pack_mapped)
891 peak_pack_mapped = pack_mapped;
892 if (pack_open_windows > peak_pack_open_windows)
893 peak_pack_open_windows = pack_open_windows;
894 win->next = p->windows;
895 p->windows = win;
898 if (win != *w_cursor) {
899 win->last_used = pack_used_ctr++;
900 win->inuse_cnt++;
901 *w_cursor = win;
903 offset -= win->offset;
904 if (left)
905 *left = win->len - xsize_t(offset);
906 return win->base + offset;
909 static struct packed_git *alloc_packed_git(int extra)
911 struct packed_git *p = xmalloc(sizeof(*p) + extra);
912 memset(p, 0, sizeof(*p));
913 p->pack_fd = -1;
914 return p;
917 static void try_to_free_pack_memory(size_t size)
919 release_pack_memory(size, -1);
922 struct packed_git *add_packed_git(const char *path, int path_len, int local)
924 static int have_set_try_to_free_routine;
925 struct stat st;
926 struct packed_git *p = alloc_packed_git(path_len + 2);
928 if (!have_set_try_to_free_routine) {
929 have_set_try_to_free_routine = 1;
930 set_try_to_free_routine(try_to_free_pack_memory);
934 * Make sure a corresponding .pack file exists and that
935 * the index looks sane.
937 path_len -= strlen(".idx");
938 if (path_len < 1) {
939 free(p);
940 return NULL;
942 memcpy(p->pack_name, path, path_len);
944 strcpy(p->pack_name + path_len, ".keep");
945 if (!access(p->pack_name, F_OK))
946 p->pack_keep = 1;
948 strcpy(p->pack_name + path_len, ".pack");
949 if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
950 free(p);
951 return NULL;
954 /* ok, it looks sane as far as we can check without
955 * actually mapping the pack file.
957 p->pack_size = st.st_size;
958 p->pack_local = local;
959 p->mtime = st.st_mtime;
960 if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
961 hashclr(p->sha1);
962 return p;
965 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
967 const char *path = sha1_pack_name(sha1);
968 struct packed_git *p = alloc_packed_git(strlen(path) + 1);
970 strcpy(p->pack_name, path);
971 hashcpy(p->sha1, sha1);
972 if (check_packed_git_idx(idx_path, p)) {
973 free(p);
974 return NULL;
977 return p;
980 void install_packed_git(struct packed_git *pack)
982 if (pack->pack_fd != -1)
983 pack_open_fds++;
985 pack->next = packed_git;
986 packed_git = pack;
989 static void prepare_packed_git_one(char *objdir, int local)
991 /* Ensure that this buffer is large enough so that we can
992 append "/pack/" without clobbering the stack even if
993 strlen(objdir) were PATH_MAX. */
994 char path[PATH_MAX + 1 + 4 + 1 + 1];
995 int len;
996 DIR *dir;
997 struct dirent *de;
999 sprintf(path, "%s/pack", objdir);
1000 len = strlen(path);
1001 dir = opendir(path);
1002 if (!dir) {
1003 if (errno != ENOENT)
1004 error("unable to open object pack directory: %s: %s",
1005 path, strerror(errno));
1006 return;
1008 path[len++] = '/';
1009 while ((de = readdir(dir)) != NULL) {
1010 int namelen = strlen(de->d_name);
1011 struct packed_git *p;
1013 if (!has_extension(de->d_name, ".idx"))
1014 continue;
1016 if (len + namelen + 1 > sizeof(path))
1017 continue;
1019 /* Don't reopen a pack we already have. */
1020 strcpy(path + len, de->d_name);
1021 for (p = packed_git; p; p = p->next) {
1022 if (!memcmp(path, p->pack_name, len + namelen - 4))
1023 break;
1025 if (p)
1026 continue;
1027 /* See if it really is a valid .idx file with corresponding
1028 * .pack file that we can map.
1030 p = add_packed_git(path, len + namelen, local);
1031 if (!p)
1032 continue;
1033 install_packed_git(p);
1035 closedir(dir);
1038 static int sort_pack(const void *a_, const void *b_)
1040 struct packed_git *a = *((struct packed_git **)a_);
1041 struct packed_git *b = *((struct packed_git **)b_);
1042 int st;
1045 * Local packs tend to contain objects specific to our
1046 * variant of the project than remote ones. In addition,
1047 * remote ones could be on a network mounted filesystem.
1048 * Favor local ones for these reasons.
1050 st = a->pack_local - b->pack_local;
1051 if (st)
1052 return -st;
1055 * Younger packs tend to contain more recent objects,
1056 * and more recent objects tend to get accessed more
1057 * often.
1059 if (a->mtime < b->mtime)
1060 return 1;
1061 else if (a->mtime == b->mtime)
1062 return 0;
1063 return -1;
1066 static void rearrange_packed_git(void)
1068 struct packed_git **ary, *p;
1069 int i, n;
1071 for (n = 0, p = packed_git; p; p = p->next)
1072 n++;
1073 if (n < 2)
1074 return;
1076 /* prepare an array of packed_git for easier sorting */
1077 ary = xcalloc(n, sizeof(struct packed_git *));
1078 for (n = 0, p = packed_git; p; p = p->next)
1079 ary[n++] = p;
1081 qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1083 /* link them back again */
1084 for (i = 0; i < n - 1; i++)
1085 ary[i]->next = ary[i + 1];
1086 ary[n - 1]->next = NULL;
1087 packed_git = ary[0];
1089 free(ary);
1092 static int prepare_packed_git_run_once = 0;
1093 void prepare_packed_git(void)
1095 struct alternate_object_database *alt;
1097 if (prepare_packed_git_run_once)
1098 return;
1099 prepare_packed_git_one(get_object_directory(), 1);
1100 prepare_alt_odb();
1101 for (alt = alt_odb_list; alt; alt = alt->next) {
1102 alt->name[-1] = 0;
1103 prepare_packed_git_one(alt->base, 0);
1104 alt->name[-1] = '/';
1106 rearrange_packed_git();
1107 prepare_packed_git_run_once = 1;
1110 void reprepare_packed_git(void)
1112 discard_revindex();
1113 prepare_packed_git_run_once = 0;
1114 prepare_packed_git();
1117 static void mark_bad_packed_object(struct packed_git *p,
1118 const unsigned char *sha1)
1120 unsigned i;
1121 for (i = 0; i < p->num_bad_objects; i++)
1122 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1123 return;
1124 p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1));
1125 hashcpy(p->bad_object_sha1 + 20 * p->num_bad_objects, sha1);
1126 p->num_bad_objects++;
1129 static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1131 struct packed_git *p;
1132 unsigned i;
1134 for (p = packed_git; p; p = p->next)
1135 for (i = 0; i < p->num_bad_objects; i++)
1136 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1137 return p;
1138 return NULL;
1141 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
1143 unsigned char real_sha1[20];
1144 hash_sha1_file(map, size, type, real_sha1);
1145 return hashcmp(sha1, real_sha1) ? -1 : 0;
1148 static int git_open_noatime(const char *name)
1150 static int sha1_file_open_flag = O_NOATIME;
1152 for (;;) {
1153 int fd = open(name, O_RDONLY | sha1_file_open_flag);
1154 if (fd >= 0)
1155 return fd;
1157 /* Might the failure be due to O_NOATIME? */
1158 if (errno != ENOENT && sha1_file_open_flag) {
1159 sha1_file_open_flag = 0;
1160 continue;
1163 return -1;
1167 static int open_sha1_file(const unsigned char *sha1)
1169 int fd;
1170 char *name = sha1_file_name(sha1);
1171 struct alternate_object_database *alt;
1173 fd = git_open_noatime(name);
1174 if (fd >= 0)
1175 return fd;
1177 prepare_alt_odb();
1178 errno = ENOENT;
1179 for (alt = alt_odb_list; alt; alt = alt->next) {
1180 name = alt->name;
1181 fill_sha1_path(name, sha1);
1182 fd = git_open_noatime(alt->base);
1183 if (fd >= 0)
1184 return fd;
1186 return -1;
1189 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1191 void *map;
1192 int fd;
1194 fd = open_sha1_file(sha1);
1195 map = NULL;
1196 if (fd >= 0) {
1197 struct stat st;
1199 if (!fstat(fd, &st)) {
1200 *size = xsize_t(st.st_size);
1201 map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1203 close(fd);
1205 return map;
1209 * There used to be a second loose object header format which
1210 * was meant to mimic the in-pack format, allowing for direct
1211 * copy of the object data. This format turned up not to be
1212 * really worth it and we no longer write loose objects in that
1213 * format.
1215 static int experimental_loose_object(unsigned char *map)
1217 unsigned int word;
1220 * Is it a zlib-compressed buffer? If so, the first byte
1221 * must be 0x78 (15-bit window size, deflated), and the
1222 * first 16-bit word is evenly divisible by 31. If so,
1223 * we are looking at the official format, not the experimental
1224 * one.
1226 word = (map[0] << 8) + map[1];
1227 if (map[0] == 0x78 && !(word % 31))
1228 return 0;
1229 else
1230 return 1;
1233 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1234 unsigned long len, enum object_type *type, unsigned long *sizep)
1236 unsigned shift;
1237 unsigned long size, c;
1238 unsigned long used = 0;
1240 c = buf[used++];
1241 *type = (c >> 4) & 7;
1242 size = c & 15;
1243 shift = 4;
1244 while (c & 0x80) {
1245 if (len <= used || bitsizeof(long) <= shift) {
1246 error("bad object header");
1247 return 0;
1249 c = buf[used++];
1250 size += (c & 0x7f) << shift;
1251 shift += 7;
1253 *sizep = size;
1254 return used;
1257 int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1259 unsigned long size, used;
1260 static const char valid_loose_object_type[8] = {
1261 0, /* OBJ_EXT */
1262 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
1263 0, /* "delta" and others are invalid in a loose object */
1265 enum object_type type;
1267 /* Get the data stream */
1268 memset(stream, 0, sizeof(*stream));
1269 stream->next_in = map;
1270 stream->avail_in = mapsize;
1271 stream->next_out = buffer;
1272 stream->avail_out = bufsiz;
1274 if (experimental_loose_object(map)) {
1276 * The old experimental format we no longer produce;
1277 * we can still read it.
1279 used = unpack_object_header_buffer(map, mapsize, &type, &size);
1280 if (!used || !valid_loose_object_type[type])
1281 return -1;
1282 map += used;
1283 mapsize -= used;
1285 /* Set up the stream for the rest.. */
1286 stream->next_in = map;
1287 stream->avail_in = mapsize;
1288 git_inflate_init(stream);
1290 /* And generate the fake traditional header */
1291 stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
1292 typename(type), size);
1293 return 0;
1295 git_inflate_init(stream);
1296 return git_inflate(stream, 0);
1299 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1301 int bytes = strlen(buffer) + 1;
1302 unsigned char *buf = xmallocz(size);
1303 unsigned long n;
1304 int status = Z_OK;
1306 n = stream->total_out - bytes;
1307 if (n > size)
1308 n = size;
1309 memcpy(buf, (char *) buffer + bytes, n);
1310 bytes = n;
1311 if (bytes <= size) {
1313 * The above condition must be (bytes <= size), not
1314 * (bytes < size). In other words, even though we
1315 * expect no more output and set avail_out to zero,
1316 * the input zlib stream may have bytes that express
1317 * "this concludes the stream", and we *do* want to
1318 * eat that input.
1320 * Otherwise we would not be able to test that we
1321 * consumed all the input to reach the expected size;
1322 * we also want to check that zlib tells us that all
1323 * went well with status == Z_STREAM_END at the end.
1325 stream->next_out = buf + bytes;
1326 stream->avail_out = size - bytes;
1327 while (status == Z_OK)
1328 status = git_inflate(stream, Z_FINISH);
1330 if (status == Z_STREAM_END && !stream->avail_in) {
1331 git_inflate_end(stream);
1332 return buf;
1335 if (status < 0)
1336 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1337 else if (stream->avail_in)
1338 error("garbage at end of loose object '%s'",
1339 sha1_to_hex(sha1));
1340 free(buf);
1341 return NULL;
1345 * We used to just use "sscanf()", but that's actually way
1346 * too permissive for what we want to check. So do an anal
1347 * object header parse by hand.
1349 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1351 char type[10];
1352 int i;
1353 unsigned long size;
1356 * The type can be at most ten bytes (including the
1357 * terminating '\0' that we add), and is followed by
1358 * a space.
1360 i = 0;
1361 for (;;) {
1362 char c = *hdr++;
1363 if (c == ' ')
1364 break;
1365 type[i++] = c;
1366 if (i >= sizeof(type))
1367 return -1;
1369 type[i] = 0;
1372 * The length must follow immediately, and be in canonical
1373 * decimal format (ie "010" is not valid).
1375 size = *hdr++ - '0';
1376 if (size > 9)
1377 return -1;
1378 if (size) {
1379 for (;;) {
1380 unsigned long c = *hdr - '0';
1381 if (c > 9)
1382 break;
1383 hdr++;
1384 size = size * 10 + c;
1387 *sizep = size;
1390 * The length must be followed by a zero byte
1392 return *hdr ? -1 : type_from_string(type);
1395 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1397 int ret;
1398 git_zstream stream;
1399 char hdr[8192];
1401 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1402 if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1403 return NULL;
1405 return unpack_sha1_rest(&stream, hdr, *size, sha1);
1408 unsigned long get_size_from_delta(struct packed_git *p,
1409 struct pack_window **w_curs,
1410 off_t curpos)
1412 const unsigned char *data;
1413 unsigned char delta_head[20], *in;
1414 git_zstream stream;
1415 int st;
1417 memset(&stream, 0, sizeof(stream));
1418 stream.next_out = delta_head;
1419 stream.avail_out = sizeof(delta_head);
1421 git_inflate_init(&stream);
1422 do {
1423 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1424 stream.next_in = in;
1425 st = git_inflate(&stream, Z_FINISH);
1426 curpos += stream.next_in - in;
1427 } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1428 stream.total_out < sizeof(delta_head));
1429 git_inflate_end(&stream);
1430 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1431 error("delta data unpack-initial failed");
1432 return 0;
1435 /* Examine the initial part of the delta to figure out
1436 * the result size.
1438 data = delta_head;
1440 /* ignore base size */
1441 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1443 /* Read the result size */
1444 return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1447 static off_t get_delta_base(struct packed_git *p,
1448 struct pack_window **w_curs,
1449 off_t *curpos,
1450 enum object_type type,
1451 off_t delta_obj_offset)
1453 unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1454 off_t base_offset;
1456 /* use_pack() assured us we have [base_info, base_info + 20)
1457 * as a range that we can look at without walking off the
1458 * end of the mapped window. Its actually the hash size
1459 * that is assured. An OFS_DELTA longer than the hash size
1460 * is stupid, as then a REF_DELTA would be smaller to store.
1462 if (type == OBJ_OFS_DELTA) {
1463 unsigned used = 0;
1464 unsigned char c = base_info[used++];
1465 base_offset = c & 127;
1466 while (c & 128) {
1467 base_offset += 1;
1468 if (!base_offset || MSB(base_offset, 7))
1469 return 0; /* overflow */
1470 c = base_info[used++];
1471 base_offset = (base_offset << 7) + (c & 127);
1473 base_offset = delta_obj_offset - base_offset;
1474 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1475 return 0; /* out of bound */
1476 *curpos += used;
1477 } else if (type == OBJ_REF_DELTA) {
1478 /* The base entry _must_ be in the same pack */
1479 base_offset = find_pack_entry_one(base_info, p);
1480 *curpos += 20;
1481 } else
1482 die("I am totally screwed");
1483 return base_offset;
1486 /* forward declaration for a mutually recursive function */
1487 static int packed_object_info(struct packed_git *p, off_t offset,
1488 unsigned long *sizep, int *rtype);
1490 static int packed_delta_info(struct packed_git *p,
1491 struct pack_window **w_curs,
1492 off_t curpos,
1493 enum object_type type,
1494 off_t obj_offset,
1495 unsigned long *sizep)
1497 off_t base_offset;
1499 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1500 if (!base_offset)
1501 return OBJ_BAD;
1502 type = packed_object_info(p, base_offset, NULL, NULL);
1503 if (type <= OBJ_NONE) {
1504 struct revindex_entry *revidx;
1505 const unsigned char *base_sha1;
1506 revidx = find_pack_revindex(p, base_offset);
1507 if (!revidx)
1508 return OBJ_BAD;
1509 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1510 mark_bad_packed_object(p, base_sha1);
1511 type = sha1_object_info(base_sha1, NULL);
1512 if (type <= OBJ_NONE)
1513 return OBJ_BAD;
1516 /* We choose to only get the type of the base object and
1517 * ignore potentially corrupt pack file that expects the delta
1518 * based on a base with a wrong size. This saves tons of
1519 * inflate() calls.
1521 if (sizep) {
1522 *sizep = get_size_from_delta(p, w_curs, curpos);
1523 if (*sizep == 0)
1524 type = OBJ_BAD;
1527 return type;
1530 int unpack_object_header(struct packed_git *p,
1531 struct pack_window **w_curs,
1532 off_t *curpos,
1533 unsigned long *sizep)
1535 unsigned char *base;
1536 unsigned long left;
1537 unsigned long used;
1538 enum object_type type;
1540 /* use_pack() assures us we have [base, base + 20) available
1541 * as a range that we can look at. (Its actually the hash
1542 * size that is assured.) With our object header encoding
1543 * the maximum deflated object size is 2^137, which is just
1544 * insane, so we know won't exceed what we have been given.
1546 base = use_pack(p, w_curs, *curpos, &left);
1547 used = unpack_object_header_buffer(base, left, &type, sizep);
1548 if (!used) {
1549 type = OBJ_BAD;
1550 } else
1551 *curpos += used;
1553 return type;
1556 static int packed_object_info(struct packed_git *p, off_t obj_offset,
1557 unsigned long *sizep, int *rtype)
1559 struct pack_window *w_curs = NULL;
1560 unsigned long size;
1561 off_t curpos = obj_offset;
1562 enum object_type type;
1564 type = unpack_object_header(p, &w_curs, &curpos, &size);
1565 if (rtype)
1566 *rtype = type; /* representation type */
1568 switch (type) {
1569 case OBJ_OFS_DELTA:
1570 case OBJ_REF_DELTA:
1571 type = packed_delta_info(p, &w_curs, curpos,
1572 type, obj_offset, sizep);
1573 break;
1574 case OBJ_COMMIT:
1575 case OBJ_TREE:
1576 case OBJ_BLOB:
1577 case OBJ_TAG:
1578 if (sizep)
1579 *sizep = size;
1580 break;
1581 default:
1582 error("unknown object type %i at offset %"PRIuMAX" in %s",
1583 type, (uintmax_t)obj_offset, p->pack_name);
1584 type = OBJ_BAD;
1586 unuse_pack(&w_curs);
1587 return type;
1590 static void *unpack_compressed_entry(struct packed_git *p,
1591 struct pack_window **w_curs,
1592 off_t curpos,
1593 unsigned long size)
1595 int st;
1596 git_zstream stream;
1597 unsigned char *buffer, *in;
1599 buffer = xmallocz(size);
1600 memset(&stream, 0, sizeof(stream));
1601 stream.next_out = buffer;
1602 stream.avail_out = size + 1;
1604 git_inflate_init(&stream);
1605 do {
1606 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1607 stream.next_in = in;
1608 st = git_inflate(&stream, Z_FINISH);
1609 if (!stream.avail_out)
1610 break; /* the payload is larger than it should be */
1611 curpos += stream.next_in - in;
1612 } while (st == Z_OK || st == Z_BUF_ERROR);
1613 git_inflate_end(&stream);
1614 if ((st != Z_STREAM_END) || stream.total_out != size) {
1615 free(buffer);
1616 return NULL;
1619 return buffer;
1622 #define MAX_DELTA_CACHE (256)
1624 static size_t delta_base_cached;
1626 static struct delta_base_cache_lru_list {
1627 struct delta_base_cache_lru_list *prev;
1628 struct delta_base_cache_lru_list *next;
1629 } delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
1631 static struct delta_base_cache_entry {
1632 struct delta_base_cache_lru_list lru;
1633 void *data;
1634 struct packed_git *p;
1635 off_t base_offset;
1636 unsigned long size;
1637 enum object_type type;
1638 } delta_base_cache[MAX_DELTA_CACHE];
1640 static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
1642 unsigned long hash;
1644 hash = (unsigned long)p + (unsigned long)base_offset;
1645 hash += (hash >> 8) + (hash >> 16);
1646 return hash % MAX_DELTA_CACHE;
1649 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1651 unsigned long hash = pack_entry_hash(p, base_offset);
1652 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1653 return (ent->data && ent->p == p && ent->base_offset == base_offset);
1656 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1657 unsigned long *base_size, enum object_type *type, int keep_cache)
1659 void *ret;
1660 unsigned long hash = pack_entry_hash(p, base_offset);
1661 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1663 ret = ent->data;
1664 if (!ret || ent->p != p || ent->base_offset != base_offset)
1665 return unpack_entry(p, base_offset, type, base_size);
1667 if (!keep_cache) {
1668 ent->data = NULL;
1669 ent->lru.next->prev = ent->lru.prev;
1670 ent->lru.prev->next = ent->lru.next;
1671 delta_base_cached -= ent->size;
1672 } else {
1673 ret = xmemdupz(ent->data, ent->size);
1675 *type = ent->type;
1676 *base_size = ent->size;
1677 return ret;
1680 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1682 if (ent->data) {
1683 free(ent->data);
1684 ent->data = NULL;
1685 ent->lru.next->prev = ent->lru.prev;
1686 ent->lru.prev->next = ent->lru.next;
1687 delta_base_cached -= ent->size;
1691 void clear_delta_base_cache(void)
1693 unsigned long p;
1694 for (p = 0; p < MAX_DELTA_CACHE; p++)
1695 release_delta_base_cache(&delta_base_cache[p]);
1698 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1699 void *base, unsigned long base_size, enum object_type type)
1701 unsigned long hash = pack_entry_hash(p, base_offset);
1702 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1703 struct delta_base_cache_lru_list *lru;
1705 release_delta_base_cache(ent);
1706 delta_base_cached += base_size;
1708 for (lru = delta_base_cache_lru.next;
1709 delta_base_cached > delta_base_cache_limit
1710 && lru != &delta_base_cache_lru;
1711 lru = lru->next) {
1712 struct delta_base_cache_entry *f = (void *)lru;
1713 if (f->type == OBJ_BLOB)
1714 release_delta_base_cache(f);
1716 for (lru = delta_base_cache_lru.next;
1717 delta_base_cached > delta_base_cache_limit
1718 && lru != &delta_base_cache_lru;
1719 lru = lru->next) {
1720 struct delta_base_cache_entry *f = (void *)lru;
1721 release_delta_base_cache(f);
1724 ent->p = p;
1725 ent->base_offset = base_offset;
1726 ent->type = type;
1727 ent->data = base;
1728 ent->size = base_size;
1729 ent->lru.next = &delta_base_cache_lru;
1730 ent->lru.prev = delta_base_cache_lru.prev;
1731 delta_base_cache_lru.prev->next = &ent->lru;
1732 delta_base_cache_lru.prev = &ent->lru;
1735 static void *read_object(const unsigned char *sha1, enum object_type *type,
1736 unsigned long *size);
1738 static void *unpack_delta_entry(struct packed_git *p,
1739 struct pack_window **w_curs,
1740 off_t curpos,
1741 unsigned long delta_size,
1742 off_t obj_offset,
1743 enum object_type *type,
1744 unsigned long *sizep)
1746 void *delta_data, *result, *base;
1747 unsigned long base_size;
1748 off_t base_offset;
1750 base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
1751 if (!base_offset) {
1752 error("failed to validate delta base reference "
1753 "at offset %"PRIuMAX" from %s",
1754 (uintmax_t)curpos, p->pack_name);
1755 return NULL;
1757 unuse_pack(w_curs);
1758 base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
1759 if (!base) {
1761 * We're probably in deep shit, but let's try to fetch
1762 * the required base anyway from another pack or loose.
1763 * This is costly but should happen only in the presence
1764 * of a corrupted pack, and is better than failing outright.
1766 struct revindex_entry *revidx;
1767 const unsigned char *base_sha1;
1768 revidx = find_pack_revindex(p, base_offset);
1769 if (!revidx)
1770 return NULL;
1771 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1772 error("failed to read delta base object %s"
1773 " at offset %"PRIuMAX" from %s",
1774 sha1_to_hex(base_sha1), (uintmax_t)base_offset,
1775 p->pack_name);
1776 mark_bad_packed_object(p, base_sha1);
1777 base = read_object(base_sha1, type, &base_size);
1778 if (!base)
1779 return NULL;
1782 delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
1783 if (!delta_data) {
1784 error("failed to unpack compressed delta "
1785 "at offset %"PRIuMAX" from %s",
1786 (uintmax_t)curpos, p->pack_name);
1787 free(base);
1788 return NULL;
1790 result = patch_delta(base, base_size,
1791 delta_data, delta_size,
1792 sizep);
1793 if (!result)
1794 die("failed to apply delta");
1795 free(delta_data);
1796 add_delta_base_cache(p, base_offset, base, base_size, *type);
1797 return result;
1800 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1802 static FILE *log_file;
1804 if (!log_file) {
1805 log_file = fopen(log_pack_access, "w");
1806 if (!log_file) {
1807 error("cannot open pack access log '%s' for writing: %s",
1808 log_pack_access, strerror(errno));
1809 log_pack_access = NULL;
1810 return;
1813 fprintf(log_file, "%s %"PRIuMAX"\n",
1814 p->pack_name, (uintmax_t)obj_offset);
1815 fflush(log_file);
1818 int do_check_packed_object_crc;
1820 void *unpack_entry(struct packed_git *p, off_t obj_offset,
1821 enum object_type *type, unsigned long *sizep)
1823 struct pack_window *w_curs = NULL;
1824 off_t curpos = obj_offset;
1825 void *data;
1827 if (log_pack_access)
1828 write_pack_access_log(p, obj_offset);
1830 if (do_check_packed_object_crc && p->index_version > 1) {
1831 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1832 unsigned long len = revidx[1].offset - obj_offset;
1833 if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1834 const unsigned char *sha1 =
1835 nth_packed_object_sha1(p, revidx->nr);
1836 error("bad packed object CRC for %s",
1837 sha1_to_hex(sha1));
1838 mark_bad_packed_object(p, sha1);
1839 unuse_pack(&w_curs);
1840 return NULL;
1844 *type = unpack_object_header(p, &w_curs, &curpos, sizep);
1845 switch (*type) {
1846 case OBJ_OFS_DELTA:
1847 case OBJ_REF_DELTA:
1848 data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
1849 obj_offset, type, sizep);
1850 break;
1851 case OBJ_COMMIT:
1852 case OBJ_TREE:
1853 case OBJ_BLOB:
1854 case OBJ_TAG:
1855 data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
1856 break;
1857 default:
1858 data = NULL;
1859 error("unknown object type %i at offset %"PRIuMAX" in %s",
1860 *type, (uintmax_t)obj_offset, p->pack_name);
1862 unuse_pack(&w_curs);
1863 return data;
1866 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1867 uint32_t n)
1869 const unsigned char *index = p->index_data;
1870 if (!index) {
1871 if (open_pack_index(p))
1872 return NULL;
1873 index = p->index_data;
1875 if (n >= p->num_objects)
1876 return NULL;
1877 index += 4 * 256;
1878 if (p->index_version == 1) {
1879 return index + 24 * n + 4;
1880 } else {
1881 index += 8;
1882 return index + 20 * n;
1886 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1888 const unsigned char *index = p->index_data;
1889 index += 4 * 256;
1890 if (p->index_version == 1) {
1891 return ntohl(*((uint32_t *)(index + 24 * n)));
1892 } else {
1893 uint32_t off;
1894 index += 8 + p->num_objects * (20 + 4);
1895 off = ntohl(*((uint32_t *)(index + 4 * n)));
1896 if (!(off & 0x80000000))
1897 return off;
1898 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1899 return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
1900 ntohl(*((uint32_t *)(index + 4)));
1904 off_t find_pack_entry_one(const unsigned char *sha1,
1905 struct packed_git *p)
1907 const uint32_t *level1_ofs = p->index_data;
1908 const unsigned char *index = p->index_data;
1909 unsigned hi, lo, stride;
1910 static int use_lookup = -1;
1911 static int debug_lookup = -1;
1913 if (debug_lookup < 0)
1914 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
1916 if (!index) {
1917 if (open_pack_index(p))
1918 return 0;
1919 level1_ofs = p->index_data;
1920 index = p->index_data;
1922 if (p->index_version > 1) {
1923 level1_ofs += 2;
1924 index += 8;
1926 index += 4 * 256;
1927 hi = ntohl(level1_ofs[*sha1]);
1928 lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1929 if (p->index_version > 1) {
1930 stride = 20;
1931 } else {
1932 stride = 24;
1933 index += 4;
1936 if (debug_lookup)
1937 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
1938 sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
1940 if (use_lookup < 0)
1941 use_lookup = !!getenv("GIT_USE_LOOKUP");
1942 if (use_lookup) {
1943 int pos = sha1_entry_pos(index, stride, 0,
1944 lo, hi, p->num_objects, sha1);
1945 if (pos < 0)
1946 return 0;
1947 return nth_packed_object_offset(p, pos);
1950 do {
1951 unsigned mi = (lo + hi) / 2;
1952 int cmp = hashcmp(index + mi * stride, sha1);
1954 if (debug_lookup)
1955 printf("lo %u hi %u rg %u mi %u\n",
1956 lo, hi, hi - lo, mi);
1957 if (!cmp)
1958 return nth_packed_object_offset(p, mi);
1959 if (cmp > 0)
1960 hi = mi;
1961 else
1962 lo = mi+1;
1963 } while (lo < hi);
1964 return 0;
1967 static int is_pack_valid(struct packed_git *p)
1969 /* An already open pack is known to be valid. */
1970 if (p->pack_fd != -1)
1971 return 1;
1973 /* If the pack has one window completely covering the
1974 * file size, the pack is known to be valid even if
1975 * the descriptor is not currently open.
1977 if (p->windows) {
1978 struct pack_window *w = p->windows;
1980 if (!w->offset && w->len == p->pack_size)
1981 return 1;
1984 /* Force the pack to open to prove its valid. */
1985 return !open_packed_git(p);
1988 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1990 static struct packed_git *last_found = (void *)1;
1991 struct packed_git *p;
1992 off_t offset;
1994 prepare_packed_git();
1995 if (!packed_git)
1996 return 0;
1997 p = (last_found == (void *)1) ? packed_git : last_found;
1999 do {
2000 if (p->num_bad_objects) {
2001 unsigned i;
2002 for (i = 0; i < p->num_bad_objects; i++)
2003 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
2004 goto next;
2007 offset = find_pack_entry_one(sha1, p);
2008 if (offset) {
2010 * We are about to tell the caller where they can
2011 * locate the requested object. We better make
2012 * sure the packfile is still here and can be
2013 * accessed before supplying that answer, as
2014 * it may have been deleted since the index
2015 * was loaded!
2017 if (!is_pack_valid(p)) {
2018 error("packfile %s cannot be accessed", p->pack_name);
2019 goto next;
2021 e->offset = offset;
2022 e->p = p;
2023 hashcpy(e->sha1, sha1);
2024 last_found = p;
2025 return 1;
2028 next:
2029 if (p == last_found)
2030 p = packed_git;
2031 else
2032 p = p->next;
2033 if (p == last_found)
2034 p = p->next;
2035 } while (p);
2036 return 0;
2039 struct packed_git *find_sha1_pack(const unsigned char *sha1,
2040 struct packed_git *packs)
2042 struct packed_git *p;
2044 for (p = packs; p; p = p->next) {
2045 if (find_pack_entry_one(sha1, p))
2046 return p;
2048 return NULL;
2052 static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
2054 int status;
2055 unsigned long mapsize, size;
2056 void *map;
2057 git_zstream stream;
2058 char hdr[32];
2060 map = map_sha1_file(sha1, &mapsize);
2061 if (!map)
2062 return error("unable to find %s", sha1_to_hex(sha1));
2063 if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2064 status = error("unable to unpack %s header",
2065 sha1_to_hex(sha1));
2066 else if ((status = parse_sha1_header(hdr, &size)) < 0)
2067 status = error("unable to parse %s header", sha1_to_hex(sha1));
2068 else if (sizep)
2069 *sizep = size;
2070 git_inflate_end(&stream);
2071 munmap(map, mapsize);
2072 return status;
2075 /* returns enum object_type or negative */
2076 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
2078 struct cached_object *co;
2079 struct pack_entry e;
2080 int status, rtype;
2082 co = find_cached_object(sha1);
2083 if (co) {
2084 if (oi->sizep)
2085 *(oi->sizep) = co->size;
2086 oi->whence = OI_CACHED;
2087 return co->type;
2090 if (!find_pack_entry(sha1, &e)) {
2091 /* Most likely it's a loose object. */
2092 status = sha1_loose_object_info(sha1, oi->sizep);
2093 if (status >= 0) {
2094 oi->whence = OI_LOOSE;
2095 return status;
2098 /* Not a loose object; someone else may have just packed it. */
2099 reprepare_packed_git();
2100 if (!find_pack_entry(sha1, &e))
2101 return status;
2104 status = packed_object_info(e.p, e.offset, oi->sizep, &rtype);
2105 if (status < 0) {
2106 mark_bad_packed_object(e.p, sha1);
2107 status = sha1_object_info_extended(sha1, oi);
2108 } else if (in_delta_base_cache(e.p, e.offset)) {
2109 oi->whence = OI_DBCACHED;
2110 } else {
2111 oi->whence = OI_PACKED;
2112 oi->u.packed.offset = e.offset;
2113 oi->u.packed.pack = e.p;
2114 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
2115 rtype == OBJ_OFS_DELTA);
2118 return status;
2121 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2123 struct object_info oi;
2125 oi.sizep = sizep;
2126 return sha1_object_info_extended(sha1, &oi);
2129 static void *read_packed_sha1(const unsigned char *sha1,
2130 enum object_type *type, unsigned long *size)
2132 struct pack_entry e;
2133 void *data;
2135 if (!find_pack_entry(sha1, &e))
2136 return NULL;
2137 data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
2138 if (!data) {
2140 * We're probably in deep shit, but let's try to fetch
2141 * the required object anyway from another pack or loose.
2142 * This should happen only in the presence of a corrupted
2143 * pack, and is better than failing outright.
2145 error("failed to read object %s at offset %"PRIuMAX" from %s",
2146 sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2147 mark_bad_packed_object(e.p, sha1);
2148 data = read_object(sha1, type, size);
2150 return data;
2153 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2154 unsigned char *sha1)
2156 struct cached_object *co;
2158 hash_sha1_file(buf, len, typename(type), sha1);
2159 if (has_sha1_file(sha1) || find_cached_object(sha1))
2160 return 0;
2161 if (cached_object_alloc <= cached_object_nr) {
2162 cached_object_alloc = alloc_nr(cached_object_alloc);
2163 cached_objects = xrealloc(cached_objects,
2164 sizeof(*cached_objects) *
2165 cached_object_alloc);
2167 co = &cached_objects[cached_object_nr++];
2168 co->size = len;
2169 co->type = type;
2170 co->buf = xmalloc(len);
2171 memcpy(co->buf, buf, len);
2172 hashcpy(co->sha1, sha1);
2173 return 0;
2176 static void *read_object(const unsigned char *sha1, enum object_type *type,
2177 unsigned long *size)
2179 unsigned long mapsize;
2180 void *map, *buf;
2181 struct cached_object *co;
2183 co = find_cached_object(sha1);
2184 if (co) {
2185 *type = co->type;
2186 *size = co->size;
2187 return xmemdupz(co->buf, co->size);
2190 buf = read_packed_sha1(sha1, type, size);
2191 if (buf)
2192 return buf;
2193 map = map_sha1_file(sha1, &mapsize);
2194 if (map) {
2195 buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2196 munmap(map, mapsize);
2197 return buf;
2199 reprepare_packed_git();
2200 return read_packed_sha1(sha1, type, size);
2204 * This function dies on corrupt objects; the callers who want to
2205 * deal with them should arrange to call read_object() and give error
2206 * messages themselves.
2208 void *read_sha1_file_extended(const unsigned char *sha1,
2209 enum object_type *type,
2210 unsigned long *size,
2211 unsigned flag)
2213 void *data;
2214 char *path;
2215 const struct packed_git *p;
2216 const unsigned char *repl = (flag & READ_SHA1_FILE_REPLACE)
2217 ? lookup_replace_object(sha1) : sha1;
2219 errno = 0;
2220 data = read_object(repl, type, size);
2221 if (data)
2222 return data;
2224 if (errno && errno != ENOENT)
2225 die_errno("failed to read object %s", sha1_to_hex(sha1));
2227 /* die if we replaced an object with one that does not exist */
2228 if (repl != sha1)
2229 die("replacement %s not found for %s",
2230 sha1_to_hex(repl), sha1_to_hex(sha1));
2232 if (has_loose_object(repl)) {
2233 path = sha1_file_name(sha1);
2234 die("loose object %s (stored in %s) is corrupt",
2235 sha1_to_hex(repl), path);
2238 if ((p = has_packed_and_bad(repl)) != NULL)
2239 die("packed object %s (stored in %s) is corrupt",
2240 sha1_to_hex(repl), p->pack_name);
2242 return NULL;
2245 void *read_object_with_reference(const unsigned char *sha1,
2246 const char *required_type_name,
2247 unsigned long *size,
2248 unsigned char *actual_sha1_return)
2250 enum object_type type, required_type;
2251 void *buffer;
2252 unsigned long isize;
2253 unsigned char actual_sha1[20];
2255 required_type = type_from_string(required_type_name);
2256 hashcpy(actual_sha1, sha1);
2257 while (1) {
2258 int ref_length = -1;
2259 const char *ref_type = NULL;
2261 buffer = read_sha1_file(actual_sha1, &type, &isize);
2262 if (!buffer)
2263 return NULL;
2264 if (type == required_type) {
2265 *size = isize;
2266 if (actual_sha1_return)
2267 hashcpy(actual_sha1_return, actual_sha1);
2268 return buffer;
2270 /* Handle references */
2271 else if (type == OBJ_COMMIT)
2272 ref_type = "tree ";
2273 else if (type == OBJ_TAG)
2274 ref_type = "object ";
2275 else {
2276 free(buffer);
2277 return NULL;
2279 ref_length = strlen(ref_type);
2281 if (ref_length + 40 > isize ||
2282 memcmp(buffer, ref_type, ref_length) ||
2283 get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2284 free(buffer);
2285 return NULL;
2287 free(buffer);
2288 /* Now we have the ID of the referred-to object in
2289 * actual_sha1. Check again. */
2293 static void write_sha1_file_prepare(const void *buf, unsigned long len,
2294 const char *type, unsigned char *sha1,
2295 char *hdr, int *hdrlen)
2297 git_SHA_CTX c;
2299 /* Generate the header */
2300 *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
2302 /* Sha1.. */
2303 git_SHA1_Init(&c);
2304 git_SHA1_Update(&c, hdr, *hdrlen);
2305 git_SHA1_Update(&c, buf, len);
2306 git_SHA1_Final(sha1, &c);
2310 * Move the just written object into its final resting place.
2311 * NEEDSWORK: this should be renamed to finalize_temp_file() as
2312 * "moving" is only a part of what it does, when no patch between
2313 * master to pu changes the call sites of this function.
2315 int move_temp_to_file(const char *tmpfile, const char *filename)
2317 int ret = 0;
2319 if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2320 goto try_rename;
2321 else if (link(tmpfile, filename))
2322 ret = errno;
2325 * Coda hack - coda doesn't like cross-directory links,
2326 * so we fall back to a rename, which will mean that it
2327 * won't be able to check collisions, but that's not a
2328 * big deal.
2330 * The same holds for FAT formatted media.
2332 * When this succeeds, we just return. We have nothing
2333 * left to unlink.
2335 if (ret && ret != EEXIST) {
2336 try_rename:
2337 if (!rename(tmpfile, filename))
2338 goto out;
2339 ret = errno;
2341 unlink_or_warn(tmpfile);
2342 if (ret) {
2343 if (ret != EEXIST) {
2344 return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
2346 /* FIXME!!! Collision check here ? */
2349 out:
2350 if (adjust_shared_perm(filename))
2351 return error("unable to set permission to '%s'", filename);
2352 return 0;
2355 static int write_buffer(int fd, const void *buf, size_t len)
2357 if (write_in_full(fd, buf, len) < 0)
2358 return error("file write error (%s)", strerror(errno));
2359 return 0;
2362 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2363 unsigned char *sha1)
2365 char hdr[32];
2366 int hdrlen;
2367 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2368 return 0;
2371 /* Finalize a file on disk, and close it. */
2372 static void close_sha1_file(int fd)
2374 if (fsync_object_files)
2375 fsync_or_die(fd, "sha1 file");
2376 if (close(fd) != 0)
2377 die_errno("error when closing sha1 file");
2380 /* Size of directory component, including the ending '/' */
2381 static inline int directory_size(const char *filename)
2383 const char *s = strrchr(filename, '/');
2384 if (!s)
2385 return 0;
2386 return s - filename + 1;
2390 * This creates a temporary file in the same directory as the final
2391 * 'filename'
2393 * We want to avoid cross-directory filename renames, because those
2394 * can have problems on various filesystems (FAT, NFS, Coda).
2396 static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
2398 int fd, dirlen = directory_size(filename);
2400 if (dirlen + 20 > bufsiz) {
2401 errno = ENAMETOOLONG;
2402 return -1;
2404 memcpy(buffer, filename, dirlen);
2405 strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
2406 fd = git_mkstemp_mode(buffer, 0444);
2407 if (fd < 0 && dirlen && errno == ENOENT) {
2408 /* Make sure the directory exists */
2409 memcpy(buffer, filename, dirlen);
2410 buffer[dirlen-1] = 0;
2411 if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
2412 return -1;
2414 /* Try again */
2415 strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
2416 fd = git_mkstemp_mode(buffer, 0444);
2418 return fd;
2421 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
2422 const void *buf, unsigned long len, time_t mtime)
2424 int fd, ret;
2425 unsigned char compressed[4096];
2426 git_zstream stream;
2427 git_SHA_CTX c;
2428 unsigned char parano_sha1[20];
2429 char *filename;
2430 static char tmpfile[PATH_MAX];
2432 filename = sha1_file_name(sha1);
2433 fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
2434 if (fd < 0) {
2435 if (errno == EACCES)
2436 return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
2437 else
2438 return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
2441 /* Set it up */
2442 memset(&stream, 0, sizeof(stream));
2443 git_deflate_init(&stream, zlib_compression_level);
2444 stream.next_out = compressed;
2445 stream.avail_out = sizeof(compressed);
2446 git_SHA1_Init(&c);
2448 /* First header.. */
2449 stream.next_in = (unsigned char *)hdr;
2450 stream.avail_in = hdrlen;
2451 while (git_deflate(&stream, 0) == Z_OK)
2452 ; /* nothing */
2453 git_SHA1_Update(&c, hdr, hdrlen);
2455 /* Then the data itself.. */
2456 stream.next_in = (void *)buf;
2457 stream.avail_in = len;
2458 do {
2459 unsigned char *in0 = stream.next_in;
2460 ret = git_deflate(&stream, Z_FINISH);
2461 git_SHA1_Update(&c, in0, stream.next_in - in0);
2462 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
2463 die("unable to write sha1 file");
2464 stream.next_out = compressed;
2465 stream.avail_out = sizeof(compressed);
2466 } while (ret == Z_OK);
2468 if (ret != Z_STREAM_END)
2469 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
2470 ret = git_deflate_end_gently(&stream);
2471 if (ret != Z_OK)
2472 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
2473 git_SHA1_Final(parano_sha1, &c);
2474 if (hashcmp(sha1, parano_sha1) != 0)
2475 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
2477 close_sha1_file(fd);
2479 if (mtime) {
2480 struct utimbuf utb;
2481 utb.actime = mtime;
2482 utb.modtime = mtime;
2483 if (utime(tmpfile, &utb) < 0)
2484 warning("failed utime() on %s: %s",
2485 tmpfile, strerror(errno));
2488 return move_temp_to_file(tmpfile, filename);
2491 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
2493 unsigned char sha1[20];
2494 char hdr[32];
2495 int hdrlen;
2497 /* Normally if we have it in the pack then we do not bother writing
2498 * it out into .git/objects/??/?{38} file.
2500 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2501 if (returnsha1)
2502 hashcpy(returnsha1, sha1);
2503 if (has_sha1_file(sha1))
2504 return 0;
2505 return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
2508 int force_object_loose(const unsigned char *sha1, time_t mtime)
2510 void *buf;
2511 unsigned long len;
2512 enum object_type type;
2513 char hdr[32];
2514 int hdrlen;
2515 int ret;
2517 if (has_loose_object(sha1))
2518 return 0;
2519 buf = read_packed_sha1(sha1, &type, &len);
2520 if (!buf)
2521 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
2522 hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
2523 ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
2524 free(buf);
2526 return ret;
2529 int has_pack_index(const unsigned char *sha1)
2531 struct stat st;
2532 if (stat(sha1_pack_index_name(sha1), &st))
2533 return 0;
2534 return 1;
2537 int has_sha1_pack(const unsigned char *sha1)
2539 struct pack_entry e;
2540 return find_pack_entry(sha1, &e);
2543 int has_sha1_file(const unsigned char *sha1)
2545 struct pack_entry e;
2547 if (find_pack_entry(sha1, &e))
2548 return 1;
2549 return has_loose_object(sha1);
2552 static void check_tree(const void *buf, size_t size)
2554 struct tree_desc desc;
2555 struct name_entry entry;
2557 init_tree_desc(&desc, buf, size);
2558 while (tree_entry(&desc, &entry))
2559 /* do nothing
2560 * tree_entry() will die() on malformed entries */
2564 static void check_commit(const void *buf, size_t size)
2566 struct commit c;
2567 memset(&c, 0, sizeof(c));
2568 if (parse_commit_buffer(&c, buf, size))
2569 die("corrupt commit");
2572 static void check_tag(const void *buf, size_t size)
2574 struct tag t;
2575 memset(&t, 0, sizeof(t));
2576 if (parse_tag_buffer(&t, buf, size))
2577 die("corrupt tag");
2580 static int index_mem(unsigned char *sha1, void *buf, size_t size,
2581 enum object_type type,
2582 const char *path, unsigned flags)
2584 int ret, re_allocated = 0;
2585 int write_object = flags & HASH_WRITE_OBJECT;
2587 if (!type)
2588 type = OBJ_BLOB;
2591 * Convert blobs to git internal format
2593 if ((type == OBJ_BLOB) && path) {
2594 struct strbuf nbuf = STRBUF_INIT;
2595 if (convert_to_git(path, buf, size, &nbuf,
2596 write_object ? safe_crlf : 0)) {
2597 buf = strbuf_detach(&nbuf, &size);
2598 re_allocated = 1;
2601 if (flags & HASH_FORMAT_CHECK) {
2602 if (type == OBJ_TREE)
2603 check_tree(buf, size);
2604 if (type == OBJ_COMMIT)
2605 check_commit(buf, size);
2606 if (type == OBJ_TAG)
2607 check_tag(buf, size);
2610 if (write_object)
2611 ret = write_sha1_file(buf, size, typename(type), sha1);
2612 else
2613 ret = hash_sha1_file(buf, size, typename(type), sha1);
2614 if (re_allocated)
2615 free(buf);
2616 return ret;
2619 static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
2620 const char *path, unsigned flags)
2622 struct strbuf sbuf = STRBUF_INIT;
2623 int ret;
2625 if (strbuf_read(&sbuf, fd, 4096) >= 0)
2626 ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
2627 else
2628 ret = -1;
2629 strbuf_release(&sbuf);
2630 return ret;
2633 #define SMALL_FILE_SIZE (32*1024)
2635 static int index_core(unsigned char *sha1, int fd, size_t size,
2636 enum object_type type, const char *path,
2637 unsigned flags)
2639 int ret;
2641 if (!size) {
2642 ret = index_mem(sha1, NULL, size, type, path, flags);
2643 } else if (size <= SMALL_FILE_SIZE) {
2644 char *buf = xmalloc(size);
2645 if (size == read_in_full(fd, buf, size))
2646 ret = index_mem(sha1, buf, size, type, path, flags);
2647 else
2648 ret = error("short read %s", strerror(errno));
2649 free(buf);
2650 } else {
2651 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2652 ret = index_mem(sha1, buf, size, type, path, flags);
2653 munmap(buf, size);
2655 return ret;
2659 * This creates one packfile per large blob, because the caller
2660 * immediately wants the result sha1, and fast-import can report the
2661 * object name via marks mechanism only by closing the created
2662 * packfile.
2664 * This also bypasses the usual "convert-to-git" dance, and that is on
2665 * purpose. We could write a streaming version of the converting
2666 * functions and insert that before feeding the data to fast-import
2667 * (or equivalent in-core API described above), but the primary
2668 * motivation for trying to stream from the working tree file and to
2669 * avoid mmaping it in core is to deal with large binary blobs, and
2670 * by definition they do _not_ want to get any conversion.
2672 static int index_stream(unsigned char *sha1, int fd, size_t size,
2673 enum object_type type, const char *path,
2674 unsigned flags)
2676 struct child_process fast_import;
2677 char export_marks[512];
2678 const char *argv[] = { "fast-import", "--quiet", export_marks, NULL };
2679 char tmpfile[512];
2680 char fast_import_cmd[512];
2681 char buf[512];
2682 int len, tmpfd;
2684 strcpy(tmpfile, git_path("hashstream_XXXXXX"));
2685 tmpfd = git_mkstemp_mode(tmpfile, 0600);
2686 if (tmpfd < 0)
2687 die_errno("cannot create tempfile: %s", tmpfile);
2688 if (close(tmpfd))
2689 die_errno("cannot close tempfile: %s", tmpfile);
2690 sprintf(export_marks, "--export-marks=%s", tmpfile);
2692 memset(&fast_import, 0, sizeof(fast_import));
2693 fast_import.in = -1;
2694 fast_import.argv = argv;
2695 fast_import.git_cmd = 1;
2696 if (start_command(&fast_import))
2697 die_errno("index-stream: git fast-import failed");
2699 len = sprintf(fast_import_cmd, "blob\nmark :1\ndata %lu\n",
2700 (unsigned long) size);
2701 write_or_whine(fast_import.in, fast_import_cmd, len,
2702 "index-stream: feeding fast-import");
2703 while (size) {
2704 char buf[10240];
2705 size_t sz = size < sizeof(buf) ? size : sizeof(buf);
2706 ssize_t actual;
2708 actual = read_in_full(fd, buf, sz);
2709 if (actual < 0)
2710 die_errno("index-stream: reading input");
2711 if (write_in_full(fast_import.in, buf, actual) != actual)
2712 die_errno("index-stream: feeding fast-import");
2713 size -= actual;
2715 if (close(fast_import.in))
2716 die_errno("index-stream: closing fast-import");
2717 if (finish_command(&fast_import))
2718 die_errno("index-stream: finishing fast-import");
2720 tmpfd = open(tmpfile, O_RDONLY);
2721 if (tmpfd < 0)
2722 die_errno("index-stream: cannot open fast-import mark");
2723 len = read(tmpfd, buf, sizeof(buf));
2724 if (len < 0)
2725 die_errno("index-stream: reading fast-import mark");
2726 if (close(tmpfd) < 0)
2727 die_errno("index-stream: closing fast-import mark");
2728 if (unlink(tmpfile))
2729 die_errno("index-stream: unlinking fast-import mark");
2730 if (len != 44 ||
2731 memcmp(":1 ", buf, 3) ||
2732 get_sha1_hex(buf + 3, sha1))
2733 die_errno("index-stream: unexpected fast-import mark: <%s>", buf);
2734 return 0;
2737 int index_fd(unsigned char *sha1, int fd, struct stat *st,
2738 enum object_type type, const char *path, unsigned flags)
2740 int ret;
2741 size_t size = xsize_t(st->st_size);
2743 if (!S_ISREG(st->st_mode))
2744 ret = index_pipe(sha1, fd, type, path, flags);
2745 else if (size <= big_file_threshold || type != OBJ_BLOB)
2746 ret = index_core(sha1, fd, size, type, path, flags);
2747 else
2748 ret = index_stream(sha1, fd, size, type, path, flags);
2749 close(fd);
2750 return ret;
2753 int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
2755 int fd;
2756 struct strbuf sb = STRBUF_INIT;
2758 switch (st->st_mode & S_IFMT) {
2759 case S_IFREG:
2760 fd = open(path, O_RDONLY);
2761 if (fd < 0)
2762 return error("open(\"%s\"): %s", path,
2763 strerror(errno));
2764 if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
2765 return error("%s: failed to insert into database",
2766 path);
2767 break;
2768 case S_IFLNK:
2769 if (strbuf_readlink(&sb, path, st->st_size)) {
2770 char *errstr = strerror(errno);
2771 return error("readlink(\"%s\"): %s", path,
2772 errstr);
2774 if (!(flags & HASH_WRITE_OBJECT))
2775 hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
2776 else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
2777 return error("%s: failed to insert into database",
2778 path);
2779 strbuf_release(&sb);
2780 break;
2781 case S_IFDIR:
2782 return resolve_gitlink_ref(path, "HEAD", sha1);
2783 default:
2784 return error("%s: unsupported file type", path);
2786 return 0;
2789 int read_pack_header(int fd, struct pack_header *header)
2791 if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
2792 /* "eof before pack header was fully read" */
2793 return PH_ERROR_EOF;
2795 if (header->hdr_signature != htonl(PACK_SIGNATURE))
2796 /* "protocol error (pack signature mismatch detected)" */
2797 return PH_ERROR_PACK_SIGNATURE;
2798 if (!pack_version_ok(header->hdr_version))
2799 /* "protocol error (pack version unsupported)" */
2800 return PH_ERROR_PROTOCOL;
2801 return 0;
2804 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
2806 enum object_type type = sha1_object_info(sha1, NULL);
2807 if (type < 0)
2808 die("%s is not a valid object", sha1_to_hex(sha1));
2809 if (type != expect)
2810 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
2811 typename(expect));