![[tokkee]](http://tokkee.org/images/avatar.png){kind=avatar}
1 /*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 *
6 * This handles basic git sha1 object files - packing, unpacking,
7 * creation etc.
8 */
9 #include "cache.h"
10 #include "delta.h"
11 #include "pack.h"
12 #include "blob.h"
13 #include "commit.h"
14 #include "tag.h"
15 #include "tree.h"
16 #include "refs.h"
17 #include "pack-revindex.h"
18 #include "sha1-lookup.h"
20 #ifndef O_NOATIME
21 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
22 #define O_NOATIME 01000000
23 #else
24 #define O_NOATIME 0
25 #endif
26 #endif
28 #ifdef NO_C99_FORMAT
29 #define SZ_FMT "lu"
30 static unsigned long sz_fmt(size_t s) { return (unsigned long)s; }
31 #else
32 #define SZ_FMT "zu"
33 static size_t sz_fmt(size_t s) { return s; }
34 #endif
36 const unsigned char null_sha1[20];
38 const signed char hexval_table[256] = {
39 -1, -1, -1, -1, -1, -1, -1, -1, /* 00-07 */
40 -1, -1, -1, -1, -1, -1, -1, -1, /* 08-0f */
41 -1, -1, -1, -1, -1, -1, -1, -1, /* 10-17 */
42 -1, -1, -1, -1, -1, -1, -1, -1, /* 18-1f */
43 -1, -1, -1, -1, -1, -1, -1, -1, /* 20-27 */
44 -1, -1, -1, -1, -1, -1, -1, -1, /* 28-2f */
45 0, 1, 2, 3, 4, 5, 6, 7, /* 30-37 */
46 8, 9, -1, -1, -1, -1, -1, -1, /* 38-3f */
47 -1, 10, 11, 12, 13, 14, 15, -1, /* 40-47 */
48 -1, -1, -1, -1, -1, -1, -1, -1, /* 48-4f */
49 -1, -1, -1, -1, -1, -1, -1, -1, /* 50-57 */
50 -1, -1, -1, -1, -1, -1, -1, -1, /* 58-5f */
51 -1, 10, 11, 12, 13, 14, 15, -1, /* 60-67 */
52 -1, -1, -1, -1, -1, -1, -1, -1, /* 68-67 */
53 -1, -1, -1, -1, -1, -1, -1, -1, /* 70-77 */
54 -1, -1, -1, -1, -1, -1, -1, -1, /* 78-7f */
55 -1, -1, -1, -1, -1, -1, -1, -1, /* 80-87 */
56 -1, -1, -1, -1, -1, -1, -1, -1, /* 88-8f */
57 -1, -1, -1, -1, -1, -1, -1, -1, /* 90-97 */
58 -1, -1, -1, -1, -1, -1, -1, -1, /* 98-9f */
59 -1, -1, -1, -1, -1, -1, -1, -1, /* a0-a7 */
60 -1, -1, -1, -1, -1, -1, -1, -1, /* a8-af */
61 -1, -1, -1, -1, -1, -1, -1, -1, /* b0-b7 */
62 -1, -1, -1, -1, -1, -1, -1, -1, /* b8-bf */
63 -1, -1, -1, -1, -1, -1, -1, -1, /* c0-c7 */
64 -1, -1, -1, -1, -1, -1, -1, -1, /* c8-cf */
65 -1, -1, -1, -1, -1, -1, -1, -1, /* d0-d7 */
66 -1, -1, -1, -1, -1, -1, -1, -1, /* d8-df */
67 -1, -1, -1, -1, -1, -1, -1, -1, /* e0-e7 */
68 -1, -1, -1, -1, -1, -1, -1, -1, /* e8-ef */
69 -1, -1, -1, -1, -1, -1, -1, -1, /* f0-f7 */
70 -1, -1, -1, -1, -1, -1, -1, -1, /* f8-ff */
71 };
73 int get_sha1_hex(const char *hex, unsigned char *sha1)
74 {
75 int i;
76 for (i = 0; i < 20; i++) {
77 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
78 if (val & ~0xff)
79 return -1;
80 *sha1++ = val;
81 hex += 2;
82 }
83 return 0;
84 }
86 static inline int offset_1st_component(const char *path)
87 {
88 if (has_dos_drive_prefix(path))
89 return 2 + (path[2] == '/');
90 return *path == '/';
91 }
93 int safe_create_leading_directories(char *path)
94 {
95 char *pos = path + offset_1st_component(path);
96 struct stat st;
98 while (pos) {
99 pos = strchr(pos, '/');
100 if (!pos)
101 break;
102 while (*++pos == '/')
103 ;
104 if (!*pos)
105 break;
106 *--pos = '\0';
107 if (!stat(path, &st)) {
108 /* path exists */
109 if (!S_ISDIR(st.st_mode)) {
110 *pos = '/';
111 return -3;
112 }
113 }
114 else if (mkdir(path, 0777)) {
115 *pos = '/';
116 return -1;
117 }
118 else if (adjust_shared_perm(path)) {
119 *pos = '/';
120 return -2;
121 }
122 *pos++ = '/';
123 }
124 return 0;
125 }
127 int safe_create_leading_directories_const(const char *path)
128 {
129 /* path points to cache entries, so xstrdup before messing with it */
130 char *buf = xstrdup(path);
131 int result = safe_create_leading_directories(buf);
132 free(buf);
133 return result;
134 }
136 char *sha1_to_hex(const unsigned char *sha1)
137 {
138 static int bufno;
139 static char hexbuffer[4][50];
140 static const char hex[] = "0123456789abcdef";
141 char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
142 int i;
144 for (i = 0; i < 20; i++) {
145 unsigned int val = *sha1++;
146 *buf++ = hex[val >> 4];
147 *buf++ = hex[val & 0xf];
148 }
149 *buf = '\0';
151 return buffer;
152 }
154 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
155 {
156 int i;
157 for (i = 0; i < 20; i++) {
158 static char hex[] = "0123456789abcdef";
159 unsigned int val = sha1[i];
160 char *pos = pathbuf + i*2 + (i > 0);
161 *pos++ = hex[val >> 4];
162 *pos = hex[val & 0xf];
163 }
164 }
166 /*
167 * NOTE! This returns a statically allocated buffer, so you have to be
168 * careful about using it. Do an "xstrdup()" if you need to save the
169 * filename.
170 *
171 * Also note that this returns the location for creating. Reading
172 * SHA1 file can happen from any alternate directory listed in the
173 * DB_ENVIRONMENT environment variable if it is not found in
174 * the primary object database.
175 */
176 char *sha1_file_name(const unsigned char *sha1)
177 {
178 static char *name, *base;
180 if (!base) {
181 const char *sha1_file_directory = get_object_directory();
182 int len = strlen(sha1_file_directory);
183 base = xmalloc(len + 60);
184 memcpy(base, sha1_file_directory, len);
185 memset(base+len, 0, 60);
186 base[len] = '/';
187 base[len+3] = '/';
188 name = base + len + 1;
189 }
190 fill_sha1_path(name, sha1);
191 return base;
192 }
194 static char *sha1_get_pack_name(const unsigned char *sha1,
195 char **name, char **base, const char *which)
196 {
197 static const char hex[] = "0123456789abcdef";
198 char *buf;
199 int i;
201 if (!*base) {
202 const char *sha1_file_directory = get_object_directory();
203 int len = strlen(sha1_file_directory);
204 *base = xmalloc(len + 60);
205 sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
206 sha1_file_directory, which);
207 *name = *base + len + 11;
208 }
210 buf = *name;
212 for (i = 0; i < 20; i++) {
213 unsigned int val = *sha1++;
214 *buf++ = hex[val >> 4];
215 *buf++ = hex[val & 0xf];
216 }
218 return *base;
219 }
221 char *sha1_pack_name(const unsigned char *sha1)
222 {
223 static char *name, *base;
225 return sha1_get_pack_name(sha1, &name, &base, "pack");
226 }
228 char *sha1_pack_index_name(const unsigned char *sha1)
229 {
230 static char *name, *base;
232 return sha1_get_pack_name(sha1, &name, &base, "idx");
233 }
235 struct alternate_object_database *alt_odb_list;
236 static struct alternate_object_database **alt_odb_tail;
238 static void read_info_alternates(const char * alternates, int depth);
240 /*
241 * Prepare alternate object database registry.
242 *
243 * The variable alt_odb_list points at the list of struct
244 * alternate_object_database. The elements on this list come from
245 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
246 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
247 * whose contents is similar to that environment variable but can be
248 * LF separated. Its base points at a statically allocated buffer that
249 * contains "/the/directory/corresponding/to/.git/objects/...", while
250 * its name points just after the slash at the end of ".git/objects/"
251 * in the example above, and has enough space to hold 40-byte hex
252 * SHA1, an extra slash for the first level indirection, and the
253 * terminating NUL.
254 */
255 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
256 {
257 const char *objdir = get_object_directory();
258 struct alternate_object_database *ent;
259 struct alternate_object_database *alt;
260 /* 43 = 40-byte + 2 '/' + terminating NUL */
261 int pfxlen = len;
262 int entlen = pfxlen + 43;
263 int base_len = -1;
265 if (!is_absolute_path(entry) && relative_base) {
266 /* Relative alt-odb */
267 if (base_len < 0)
268 base_len = strlen(relative_base) + 1;
269 entlen += base_len;
270 pfxlen += base_len;
271 }
272 ent = xmalloc(sizeof(*ent) + entlen);
274 if (!is_absolute_path(entry) && relative_base) {
275 memcpy(ent->base, relative_base, base_len - 1);
276 ent->base[base_len - 1] = '/';
277 memcpy(ent->base + base_len, entry, len);
278 }
279 else
280 memcpy(ent->base, entry, pfxlen);
282 ent->name = ent->base + pfxlen + 1;
283 ent->base[pfxlen + 3] = '/';
284 ent->base[pfxlen] = ent->base[entlen-1] = 0;
286 /* Detect cases where alternate disappeared */
287 if (!is_directory(ent->base)) {
288 error("object directory %s does not exist; "
289 "check .git/objects/info/alternates.",
290 ent->base);
291 free(ent);
292 return -1;
293 }
295 /* Prevent the common mistake of listing the same
296 * thing twice, or object directory itself.
297 */
298 for (alt = alt_odb_list; alt; alt = alt->next) {
299 if (!memcmp(ent->base, alt->base, pfxlen)) {
300 free(ent);
301 return -1;
302 }
303 }
304 if (!memcmp(ent->base, objdir, pfxlen)) {
305 free(ent);
306 return -1;
307 }
309 /* add the alternate entry */
310 *alt_odb_tail = ent;
311 alt_odb_tail = &(ent->next);
312 ent->next = NULL;
314 /* recursively add alternates */
315 read_info_alternates(ent->base, depth + 1);
317 ent->base[pfxlen] = '/';
319 return 0;
320 }
322 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
323 const char *relative_base, int depth)
324 {
325 const char *cp, *last;
327 if (depth > 5) {
328 error("%s: ignoring alternate object stores, nesting too deep.",
329 relative_base);
330 return;
331 }
333 last = alt;
334 while (last < ep) {
335 cp = last;
336 if (cp < ep && *cp == '#') {
337 while (cp < ep && *cp != sep)
338 cp++;
339 last = cp + 1;
340 continue;
341 }
342 while (cp < ep && *cp != sep)
343 cp++;
344 if (last != cp) {
345 if (!is_absolute_path(last) && depth) {
346 error("%s: ignoring relative alternate object store %s",
347 relative_base, last);
348 } else {
349 link_alt_odb_entry(last, cp - last,
350 relative_base, depth);
351 }
352 }
353 while (cp < ep && *cp == sep)
354 cp++;
355 last = cp;
356 }
357 }
359 static void read_info_alternates(const char * relative_base, int depth)
360 {
361 char *map;
362 size_t mapsz;
363 struct stat st;
364 const char alt_file_name[] = "info/alternates";
365 /* Given that relative_base is no longer than PATH_MAX,
366 ensure that "path" has enough space to append "/", the
367 file name, "info/alternates", and a trailing NUL. */
368 char path[PATH_MAX + 1 + sizeof alt_file_name];
369 int fd;
371 sprintf(path, "%s/%s", relative_base, alt_file_name);
372 fd = open(path, O_RDONLY);
373 if (fd < 0)
374 return;
375 if (fstat(fd, &st) || (st.st_size == 0)) {
376 close(fd);
377 return;
378 }
379 mapsz = xsize_t(st.st_size);
380 map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
381 close(fd);
383 link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth);
385 munmap(map, mapsz);
386 }
388 void add_to_alternates_file(const char *reference)
389 {
390 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
391 int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR);
392 char *alt = mkpath("%s/objects\n", reference);
393 write_or_die(fd, alt, strlen(alt));
394 if (commit_lock_file(lock))
395 die("could not close alternates file");
396 if (alt_odb_tail)
397 link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0);
398 }
400 void foreach_alt_odb(alt_odb_fn fn, void *cb)
401 {
402 struct alternate_object_database *ent;
404 prepare_alt_odb();
405 for (ent = alt_odb_list; ent; ent = ent->next)
406 if (fn(ent, cb))
407 return;
408 }
410 void prepare_alt_odb(void)
411 {
412 const char *alt;
414 if (alt_odb_tail)
415 return;
417 alt = getenv(ALTERNATE_DB_ENVIRONMENT);
418 if (!alt) alt = "";
420 alt_odb_tail = &alt_odb_list;
421 link_alt_odb_entries(alt, alt + strlen(alt), PATH_SEP, NULL, 0);
423 read_info_alternates(get_object_directory(), 0);
424 }
426 static int has_loose_object_local(const unsigned char *sha1)
427 {
428 char *name = sha1_file_name(sha1);
429 return !access(name, F_OK);
430 }
432 int has_loose_object_nonlocal(const unsigned char *sha1)
433 {
434 struct alternate_object_database *alt;
435 prepare_alt_odb();
436 for (alt = alt_odb_list; alt; alt = alt->next) {
437 fill_sha1_path(alt->name, sha1);
438 if (!access(alt->base, F_OK))
439 return 1;
440 }
441 return 0;
442 }
444 static int has_loose_object(const unsigned char *sha1)
445 {
446 return has_loose_object_local(sha1) ||
447 has_loose_object_nonlocal(sha1);
448 }
450 static unsigned int pack_used_ctr;
451 static unsigned int pack_mmap_calls;
452 static unsigned int peak_pack_open_windows;
453 static unsigned int pack_open_windows;
454 static size_t peak_pack_mapped;
455 static size_t pack_mapped;
456 struct packed_git *packed_git;
458 void pack_report(void)
459 {
460 fprintf(stderr,
461 "pack_report: getpagesize() = %10" SZ_FMT "\n"
462 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
463 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
464 sz_fmt(getpagesize()),
465 sz_fmt(packed_git_window_size),
466 sz_fmt(packed_git_limit));
467 fprintf(stderr,
468 "pack_report: pack_used_ctr = %10u\n"
469 "pack_report: pack_mmap_calls = %10u\n"
470 "pack_report: pack_open_windows = %10u / %10u\n"
471 "pack_report: pack_mapped = "
472 "%10" SZ_FMT " / %10" SZ_FMT "\n",
473 pack_used_ctr,
474 pack_mmap_calls,
475 pack_open_windows, peak_pack_open_windows,
476 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
477 }
479 static int check_packed_git_idx(const char *path, struct packed_git *p)
480 {
481 void *idx_map;
482 struct pack_idx_header *hdr;
483 size_t idx_size;
484 uint32_t version, nr, i, *index;
485 int fd = open(path, O_RDONLY);
486 struct stat st;
488 if (fd < 0)
489 return -1;
490 if (fstat(fd, &st)) {
491 close(fd);
492 return -1;
493 }
494 idx_size = xsize_t(st.st_size);
495 if (idx_size < 4 * 256 + 20 + 20) {
496 close(fd);
497 return error("index file %s is too small", path);
498 }
499 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
500 close(fd);
502 hdr = idx_map;
503 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
504 version = ntohl(hdr->idx_version);
505 if (version < 2 || version > 2) {
506 munmap(idx_map, idx_size);
507 return error("index file %s is version %"PRIu32
508 " and is not supported by this binary"
509 " (try upgrading GIT to a newer version)",
510 path, version);
511 }
512 } else
513 version = 1;
515 nr = 0;
516 index = idx_map;
517 if (version > 1)
518 index += 2; /* skip index header */
519 for (i = 0; i < 256; i++) {
520 uint32_t n = ntohl(index[i]);
521 if (n < nr) {
522 munmap(idx_map, idx_size);
523 return error("non-monotonic index %s", path);
524 }
525 nr = n;
526 }
528 if (version == 1) {
529 /*
530 * Total size:
531 * - 256 index entries 4 bytes each
532 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
533 * - 20-byte SHA1 of the packfile
534 * - 20-byte SHA1 file checksum
535 */
536 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
537 munmap(idx_map, idx_size);
538 return error("wrong index v1 file size in %s", path);
539 }
540 } else if (version == 2) {
541 /*
542 * Minimum size:
543 * - 8 bytes of header
544 * - 256 index entries 4 bytes each
545 * - 20-byte sha1 entry * nr
546 * - 4-byte crc entry * nr
547 * - 4-byte offset entry * nr
548 * - 20-byte SHA1 of the packfile
549 * - 20-byte SHA1 file checksum
550 * And after the 4-byte offset table might be a
551 * variable sized table containing 8-byte entries
552 * for offsets larger than 2^31.
553 */
554 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
555 unsigned long max_size = min_size;
556 if (nr)
557 max_size += (nr - 1)*8;
558 if (idx_size < min_size || idx_size > max_size) {
559 munmap(idx_map, idx_size);
560 return error("wrong index v2 file size in %s", path);
561 }
562 if (idx_size != min_size &&
563 /*
564 * make sure we can deal with large pack offsets.
565 * 31-bit signed offset won't be enough, neither
566 * 32-bit unsigned one will be.
567 */
568 (sizeof(off_t) <= 4)) {
569 munmap(idx_map, idx_size);
570 return error("pack too large for current definition of off_t in %s", path);
571 }
572 }
574 p->index_version = version;
575 p->index_data = idx_map;
576 p->index_size = idx_size;
577 p->num_objects = nr;
578 return 0;
579 }
581 int open_pack_index(struct packed_git *p)
582 {
583 char *idx_name;
584 int ret;
586 if (p->index_data)
587 return 0;
589 idx_name = xstrdup(p->pack_name);
590 strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
591 ret = check_packed_git_idx(idx_name, p);
592 free(idx_name);
593 return ret;
594 }
596 static void scan_windows(struct packed_git *p,
597 struct packed_git **lru_p,
598 struct pack_window **lru_w,
599 struct pack_window **lru_l)
600 {
601 struct pack_window *w, *w_l;
603 for (w_l = NULL, w = p->windows; w; w = w->next) {
604 if (!w->inuse_cnt) {
605 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
606 *lru_p = p;
607 *lru_w = w;
608 *lru_l = w_l;
609 }
610 }
611 w_l = w;
612 }
613 }
615 static int unuse_one_window(struct packed_git *current, int keep_fd)
616 {
617 struct packed_git *p, *lru_p = NULL;
618 struct pack_window *lru_w = NULL, *lru_l = NULL;
620 if (current)
621 scan_windows(current, &lru_p, &lru_w, &lru_l);
622 for (p = packed_git; p; p = p->next)
623 scan_windows(p, &lru_p, &lru_w, &lru_l);
624 if (lru_p) {
625 munmap(lru_w->base, lru_w->len);
626 pack_mapped -= lru_w->len;
627 if (lru_l)
628 lru_l->next = lru_w->next;
629 else {
630 lru_p->windows = lru_w->next;
631 if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
632 close(lru_p->pack_fd);
633 lru_p->pack_fd = -1;
634 }
635 }
636 free(lru_w);
637 pack_open_windows--;
638 return 1;
639 }
640 return 0;
641 }
643 void release_pack_memory(size_t need, int fd)
644 {
645 size_t cur = pack_mapped;
646 while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd))
647 ; /* nothing */
648 }
650 void close_pack_windows(struct packed_git *p)
651 {
652 while (p->windows) {
653 struct pack_window *w = p->windows;
655 if (w->inuse_cnt)
656 die("pack '%s' still has open windows to it",
657 p->pack_name);
658 munmap(w->base, w->len);
659 pack_mapped -= w->len;
660 pack_open_windows--;
661 p->windows = w->next;
662 free(w);
663 }
664 }
666 void unuse_pack(struct pack_window **w_cursor)
667 {
668 struct pack_window *w = *w_cursor;
669 if (w) {
670 w->inuse_cnt--;
671 *w_cursor = NULL;
672 }
673 }
675 /*
676 * This is used by git-repack in case a newly created pack happens to
677 * contain the same set of objects as an existing one. In that case
678 * the resulting file might be different even if its name would be the
679 * same. It is best to close any reference to the old pack before it is
680 * replaced on disk. Of course no index pointers nor windows for given pack
681 * must subsist at this point. If ever objects from this pack are requested
682 * again, the new version of the pack will be reinitialized through
683 * reprepare_packed_git().
684 */
685 void free_pack_by_name(const char *pack_name)
686 {
687 struct packed_git *p, **pp = &packed_git;
689 while (*pp) {
690 p = *pp;
691 if (strcmp(pack_name, p->pack_name) == 0) {
692 clear_delta_base_cache();
693 close_pack_windows(p);
694 if (p->pack_fd != -1)
695 close(p->pack_fd);
696 if (p->index_data)
697 munmap((void *)p->index_data, p->index_size);
698 free(p->bad_object_sha1);
699 *pp = p->next;
700 free(p);
701 return;
702 }
703 pp = &p->next;
704 }
705 }
707 /*
708 * Do not call this directly as this leaks p->pack_fd on error return;
709 * call open_packed_git() instead.
710 */
711 static int open_packed_git_1(struct packed_git *p)
712 {
713 struct stat st;
714 struct pack_header hdr;
715 unsigned char sha1[20];
716 unsigned char *idx_sha1;
717 long fd_flag;
719 if (!p->index_data && open_pack_index(p))
720 return error("packfile %s index unavailable", p->pack_name);
722 p->pack_fd = open(p->pack_name, O_RDONLY);
723 while (p->pack_fd < 0 && errno == EMFILE && unuse_one_window(p, -1))
724 p->pack_fd = open(p->pack_name, O_RDONLY);
725 if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
726 return -1;
728 /* If we created the struct before we had the pack we lack size. */
729 if (!p->pack_size) {
730 if (!S_ISREG(st.st_mode))
731 return error("packfile %s not a regular file", p->pack_name);
732 p->pack_size = st.st_size;
733 } else if (p->pack_size != st.st_size)
734 return error("packfile %s size changed", p->pack_name);
736 /* We leave these file descriptors open with sliding mmap;
737 * there is no point keeping them open across exec(), though.
738 */
739 fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
740 if (fd_flag < 0)
741 return error("cannot determine file descriptor flags");
742 fd_flag |= FD_CLOEXEC;
743 if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
744 return error("cannot set FD_CLOEXEC");
746 /* Verify we recognize this pack file format. */
747 if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
748 return error("file %s is far too short to be a packfile", p->pack_name);
749 if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
750 return error("file %s is not a GIT packfile", p->pack_name);
751 if (!pack_version_ok(hdr.hdr_version))
752 return error("packfile %s is version %"PRIu32" and not"
753 " supported (try upgrading GIT to a newer version)",
754 p->pack_name, ntohl(hdr.hdr_version));
756 /* Verify the pack matches its index. */
757 if (p->num_objects != ntohl(hdr.hdr_entries))
758 return error("packfile %s claims to have %"PRIu32" objects"
759 " while index indicates %"PRIu32" objects",
760 p->pack_name, ntohl(hdr.hdr_entries),
761 p->num_objects);
762 if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
763 return error("end of packfile %s is unavailable", p->pack_name);
764 if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
765 return error("packfile %s signature is unavailable", p->pack_name);
766 idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
767 if (hashcmp(sha1, idx_sha1))
768 return error("packfile %s does not match index", p->pack_name);
769 return 0;
770 }
772 static int open_packed_git(struct packed_git *p)
773 {
774 if (!open_packed_git_1(p))
775 return 0;
776 if (p->pack_fd != -1) {
777 close(p->pack_fd);
778 p->pack_fd = -1;
779 }
780 return -1;
781 }
783 static int in_window(struct pack_window *win, off_t offset)
784 {
785 /* We must promise at least 20 bytes (one hash) after the
786 * offset is available from this window, otherwise the offset
787 * is not actually in this window and a different window (which
788 * has that one hash excess) must be used. This is to support
789 * the object header and delta base parsing routines below.
790 */
791 off_t win_off = win->offset;
792 return win_off <= offset
793 && (offset + 20) <= (win_off + win->len);
794 }
796 unsigned char *use_pack(struct packed_git *p,
797 struct pack_window **w_cursor,
798 off_t offset,
799 unsigned int *left)
800 {
801 struct pack_window *win = *w_cursor;
803 if (p->pack_fd == -1 && open_packed_git(p))
804 die("packfile %s cannot be accessed", p->pack_name);
806 /* Since packfiles end in a hash of their content and it's
807 * pointless to ask for an offset into the middle of that
808 * hash, and the in_window function above wouldn't match
809 * don't allow an offset too close to the end of the file.
810 */
811 if (offset > (p->pack_size - 20))
812 die("offset beyond end of packfile (truncated pack?)");
814 if (!win || !in_window(win, offset)) {
815 if (win)
816 win->inuse_cnt--;
817 for (win = p->windows; win; win = win->next) {
818 if (in_window(win, offset))
819 break;
820 }
821 if (!win) {
822 size_t window_align = packed_git_window_size / 2;
823 off_t len;
824 win = xcalloc(1, sizeof(*win));
825 win->offset = (offset / window_align) * window_align;
826 len = p->pack_size - win->offset;
827 if (len > packed_git_window_size)
828 len = packed_git_window_size;
829 win->len = (size_t)len;
830 pack_mapped += win->len;
831 while (packed_git_limit < pack_mapped
832 && unuse_one_window(p, p->pack_fd))
833 ; /* nothing */
834 win->base = xmmap(NULL, win->len,
835 PROT_READ, MAP_PRIVATE,
836 p->pack_fd, win->offset);
837 if (win->base == MAP_FAILED)
838 die("packfile %s cannot be mapped: %s",
839 p->pack_name,
840 strerror(errno));
841 pack_mmap_calls++;
842 pack_open_windows++;
843 if (pack_mapped > peak_pack_mapped)
844 peak_pack_mapped = pack_mapped;
845 if (pack_open_windows > peak_pack_open_windows)
846 peak_pack_open_windows = pack_open_windows;
847 win->next = p->windows;
848 p->windows = win;
849 }
850 }
851 if (win != *w_cursor) {
852 win->last_used = pack_used_ctr++;
853 win->inuse_cnt++;
854 *w_cursor = win;
855 }
856 offset -= win->offset;
857 if (left)
858 *left = win->len - xsize_t(offset);
859 return win->base + offset;
860 }
862 static struct packed_git *alloc_packed_git(int extra)
863 {
864 struct packed_git *p = xmalloc(sizeof(*p) + extra);
865 memset(p, 0, sizeof(*p));
866 p->pack_fd = -1;
867 return p;
868 }
870 struct packed_git *add_packed_git(const char *path, int path_len, int local)
871 {
872 struct stat st;
873 struct packed_git *p = alloc_packed_git(path_len + 2);
875 /*
876 * Make sure a corresponding .pack file exists and that
877 * the index looks sane.
878 */
879 path_len -= strlen(".idx");
880 if (path_len < 1) {
881 free(p);
882 return NULL;
883 }
884 memcpy(p->pack_name, path, path_len);
886 strcpy(p->pack_name + path_len, ".keep");
887 if (!access(p->pack_name, F_OK))
888 p->pack_keep = 1;
890 strcpy(p->pack_name + path_len, ".pack");
891 if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
892 free(p);
893 return NULL;
894 }
896 /* ok, it looks sane as far as we can check without
897 * actually mapping the pack file.
898 */
899 p->pack_size = st.st_size;
900 p->pack_local = local;
901 p->mtime = st.st_mtime;
902 if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
903 hashclr(p->sha1);
904 return p;
905 }
907 struct packed_git *parse_pack_index(unsigned char *sha1)
908 {
909 const char *idx_path = sha1_pack_index_name(sha1);
910 const char *path = sha1_pack_name(sha1);
911 struct packed_git *p = alloc_packed_git(strlen(path) + 1);
913 strcpy(p->pack_name, path);
914 hashcpy(p->sha1, sha1);
915 if (check_packed_git_idx(idx_path, p)) {
916 free(p);
917 return NULL;
918 }
920 return p;
921 }
923 void install_packed_git(struct packed_git *pack)
924 {
925 pack->next = packed_git;
926 packed_git = pack;
927 }
929 static void prepare_packed_git_one(char *objdir, int local)
930 {
931 /* Ensure that this buffer is large enough so that we can
932 append "/pack/" without clobbering the stack even if
933 strlen(objdir) were PATH_MAX. */
934 char path[PATH_MAX + 1 + 4 + 1 + 1];
935 int len;
936 DIR *dir;
937 struct dirent *de;
939 sprintf(path, "%s/pack", objdir);
940 len = strlen(path);
941 dir = opendir(path);
942 while (!dir && errno == EMFILE && unuse_one_window(packed_git, -1))
943 dir = opendir(path);
944 if (!dir) {
945 if (errno != ENOENT)
946 error("unable to open object pack directory: %s: %s",
947 path, strerror(errno));
948 return;
949 }
950 path[len++] = '/';
951 while ((de = readdir(dir)) != NULL) {
952 int namelen = strlen(de->d_name);
953 struct packed_git *p;
955 if (!has_extension(de->d_name, ".idx"))
956 continue;
958 if (len + namelen + 1 > sizeof(path))
959 continue;
961 /* Don't reopen a pack we already have. */
962 strcpy(path + len, de->d_name);
963 for (p = packed_git; p; p = p->next) {
964 if (!memcmp(path, p->pack_name, len + namelen - 4))
965 break;
966 }
967 if (p)
968 continue;
969 /* See if it really is a valid .idx file with corresponding
970 * .pack file that we can map.
971 */
972 p = add_packed_git(path, len + namelen, local);
973 if (!p)
974 continue;
975 install_packed_git(p);
976 }
977 closedir(dir);
978 }
980 static int sort_pack(const void *a_, const void *b_)
981 {
982 struct packed_git *a = *((struct packed_git **)a_);
983 struct packed_git *b = *((struct packed_git **)b_);
984 int st;
986 /*
987 * Local packs tend to contain objects specific to our
988 * variant of the project than remote ones. In addition,
989 * remote ones could be on a network mounted filesystem.
990 * Favor local ones for these reasons.
991 */
992 st = a->pack_local - b->pack_local;
993 if (st)
994 return -st;
996 /*
997 * Younger packs tend to contain more recent objects,
998 * and more recent objects tend to get accessed more
999 * often.
1000 */
1001 if (a->mtime < b->mtime)
1002 return 1;
1003 else if (a->mtime == b->mtime)
1004 return 0;
1005 return -1;
1006 }
1008 static void rearrange_packed_git(void)
1009 {
1010 struct packed_git **ary, *p;
1011 int i, n;
1013 for (n = 0, p = packed_git; p; p = p->next)
1014 n++;
1015 if (n < 2)
1016 return;
1018 /* prepare an array of packed_git for easier sorting */
1019 ary = xcalloc(n, sizeof(struct packed_git *));
1020 for (n = 0, p = packed_git; p; p = p->next)
1021 ary[n++] = p;
1023 qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1025 /* link them back again */
1026 for (i = 0; i < n - 1; i++)
1027 ary[i]->next = ary[i + 1];
1028 ary[n - 1]->next = NULL;
1029 packed_git = ary[0];
1031 free(ary);
1032 }
1034 static int prepare_packed_git_run_once = 0;
1035 void prepare_packed_git(void)
1036 {
1037 struct alternate_object_database *alt;
1039 if (prepare_packed_git_run_once)
1040 return;
1041 prepare_packed_git_one(get_object_directory(), 1);
1042 prepare_alt_odb();
1043 for (alt = alt_odb_list; alt; alt = alt->next) {
1044 alt->name[-1] = 0;
1045 prepare_packed_git_one(alt->base, 0);
1046 alt->name[-1] = '/';
1047 }
1048 rearrange_packed_git();
1049 prepare_packed_git_run_once = 1;
1050 }
1052 void reprepare_packed_git(void)
1053 {
1054 discard_revindex();
1055 prepare_packed_git_run_once = 0;
1056 prepare_packed_git();
1057 }
1059 static void mark_bad_packed_object(struct packed_git *p,
1060 const unsigned char *sha1)
1061 {
1062 unsigned i;
1063 for (i = 0; i < p->num_bad_objects; i++)
1064 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1065 return;
1066 p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1));
1067 hashcpy(p->bad_object_sha1 + 20 * p->num_bad_objects, sha1);
1068 p->num_bad_objects++;
1069 }
1071 static int has_packed_and_bad(const unsigned char *sha1)
1072 {
1073 struct packed_git *p;
1074 unsigned i;
1076 for (p = packed_git; p; p = p->next)
1077 for (i = 0; i < p->num_bad_objects; i++)
1078 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1079 return 1;
1080 return 0;
1081 }
1083 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
1084 {
1085 unsigned char real_sha1[20];
1086 hash_sha1_file(map, size, type, real_sha1);
1087 return hashcmp(sha1, real_sha1) ? -1 : 0;
1088 }
1090 static int git_open_noatime(const char *name)
1091 {
1092 static int sha1_file_open_flag = O_NOATIME;
1093 int fd = open(name, O_RDONLY | sha1_file_open_flag);
1095 /* Might the failure be due to O_NOATIME? */
1096 if (fd < 0 && errno != ENOENT && sha1_file_open_flag) {
1097 fd = open(name, O_RDONLY);
1098 if (fd >= 0)
1099 sha1_file_open_flag = 0;
1100 }
1101 return fd;
1102 }
1104 static int open_sha1_file(const unsigned char *sha1)
1105 {
1106 int fd;
1107 char *name = sha1_file_name(sha1);
1108 struct alternate_object_database *alt;
1110 fd = git_open_noatime(name);
1111 if (fd >= 0)
1112 return fd;
1114 prepare_alt_odb();
1115 errno = ENOENT;
1116 for (alt = alt_odb_list; alt; alt = alt->next) {
1117 name = alt->name;
1118 fill_sha1_path(name, sha1);
1119 fd = git_open_noatime(alt->base);
1120 if (fd >= 0)
1121 return fd;
1122 }
1123 return -1;
1124 }
1126 static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1127 {
1128 void *map;
1129 int fd;
1131 fd = open_sha1_file(sha1);
1132 map = NULL;
1133 if (fd >= 0) {
1134 struct stat st;
1136 if (!fstat(fd, &st)) {
1137 *size = xsize_t(st.st_size);
1138 map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1139 }
1140 close(fd);
1141 }
1142 return map;
1143 }
1145 static int legacy_loose_object(unsigned char *map)
1146 {
1147 unsigned int word;
1149 /*
1150 * Is it a zlib-compressed buffer? If so, the first byte
1151 * must be 0x78 (15-bit window size, deflated), and the
1152 * first 16-bit word is evenly divisible by 31
1153 */
1154 word = (map[0] << 8) + map[1];
1155 if (map[0] == 0x78 && !(word % 31))
1156 return 1;
1157 else
1158 return 0;
1159 }
1161 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1162 unsigned long len, enum object_type *type, unsigned long *sizep)
1163 {
1164 unsigned shift;
1165 unsigned long size, c;
1166 unsigned long used = 0;
1168 c = buf[used++];
1169 *type = (c >> 4) & 7;
1170 size = c & 15;
1171 shift = 4;
1172 while (c & 0x80) {
1173 if (len <= used || bitsizeof(long) <= shift) {
1174 error("bad object header");
1175 return 0;
1176 }
1177 c = buf[used++];
1178 size += (c & 0x7f) << shift;
1179 shift += 7;
1180 }
1181 *sizep = size;
1182 return used;
1183 }
1185 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1186 {
1187 unsigned long size, used;
1188 static const char valid_loose_object_type[8] = {
1189 0, /* OBJ_EXT */
1190 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
1191 0, /* "delta" and others are invalid in a loose object */
1192 };
1193 enum object_type type;
1195 /* Get the data stream */
1196 memset(stream, 0, sizeof(*stream));
1197 stream->next_in = map;
1198 stream->avail_in = mapsize;
1199 stream->next_out = buffer;
1200 stream->avail_out = bufsiz;
1202 if (legacy_loose_object(map)) {
1203 git_inflate_init(stream);
1204 return git_inflate(stream, 0);
1205 }
1208 /*
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 don't write it any longer. But we
1213 * can still read it.
1214 */
1215 used = unpack_object_header_buffer(map, mapsize, &type, &size);
1216 if (!used || !valid_loose_object_type[type])
1217 return -1;
1218 map += used;
1219 mapsize -= used;
1221 /* Set up the stream for the rest.. */
1222 stream->next_in = map;
1223 stream->avail_in = mapsize;
1224 git_inflate_init(stream);
1226 /* And generate the fake traditional header */
1227 stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
1228 typename(type), size);
1229 return 0;
1230 }
1232 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1233 {
1234 int bytes = strlen(buffer) + 1;
1235 unsigned char *buf = xmalloc(1+size);
1236 unsigned long n;
1237 int status = Z_OK;
1239 n = stream->total_out - bytes;
1240 if (n > size)
1241 n = size;
1242 memcpy(buf, (char *) buffer + bytes, n);
1243 bytes = n;
1244 if (bytes <= size) {
1245 /*
1246 * The above condition must be (bytes <= size), not
1247 * (bytes < size). In other words, even though we
1248 * expect no more output and set avail_out to zer0,
1249 * the input zlib stream may have bytes that express
1250 * "this concludes the stream", and we *do* want to
1251 * eat that input.
1252 *
1253 * Otherwise we would not be able to test that we
1254 * consumed all the input to reach the expected size;
1255 * we also want to check that zlib tells us that all
1256 * went well with status == Z_STREAM_END at the end.
1257 */
1258 stream->next_out = buf + bytes;
1259 stream->avail_out = size - bytes;
1260 while (status == Z_OK)
1261 status = git_inflate(stream, Z_FINISH);
1262 }
1263 buf[size] = 0;
1264 if (status == Z_STREAM_END && !stream->avail_in) {
1265 git_inflate_end(stream);
1266 return buf;
1267 }
1269 if (status < 0)
1270 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1271 else if (stream->avail_in)
1272 error("garbage at end of loose object '%s'",
1273 sha1_to_hex(sha1));
1274 free(buf);
1275 return NULL;
1276 }
1278 /*
1279 * We used to just use "sscanf()", but that's actually way
1280 * too permissive for what we want to check. So do an anal
1281 * object header parse by hand.
1282 */
1283 static int parse_sha1_header(const char *hdr, unsigned long *sizep)
1284 {
1285 char type[10];
1286 int i;
1287 unsigned long size;
1289 /*
1290 * The type can be at most ten bytes (including the
1291 * terminating '\0' that we add), and is followed by
1292 * a space.
1293 */
1294 i = 0;
1295 for (;;) {
1296 char c = *hdr++;
1297 if (c == ' ')
1298 break;
1299 type[i++] = c;
1300 if (i >= sizeof(type))
1301 return -1;
1302 }
1303 type[i] = 0;
1305 /*
1306 * The length must follow immediately, and be in canonical
1307 * decimal format (ie "010" is not valid).
1308 */
1309 size = *hdr++ - '0';
1310 if (size > 9)
1311 return -1;
1312 if (size) {
1313 for (;;) {
1314 unsigned long c = *hdr - '0';
1315 if (c > 9)
1316 break;
1317 hdr++;
1318 size = size * 10 + c;
1319 }
1320 }
1321 *sizep = size;
1323 /*
1324 * The length must be followed by a zero byte
1325 */
1326 return *hdr ? -1 : type_from_string(type);
1327 }
1329 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1330 {
1331 int ret;
1332 z_stream stream;
1333 char hdr[8192];
1335 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1336 if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1337 return NULL;
1339 return unpack_sha1_rest(&stream, hdr, *size, sha1);
1340 }
1342 unsigned long get_size_from_delta(struct packed_git *p,
1343 struct pack_window **w_curs,
1344 off_t curpos)
1345 {
1346 const unsigned char *data;
1347 unsigned char delta_head[20], *in;
1348 z_stream stream;
1349 int st;
1351 memset(&stream, 0, sizeof(stream));
1352 stream.next_out = delta_head;
1353 stream.avail_out = sizeof(delta_head);
1355 git_inflate_init(&stream);
1356 do {
1357 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1358 stream.next_in = in;
1359 st = git_inflate(&stream, Z_FINISH);
1360 curpos += stream.next_in - in;
1361 } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1362 stream.total_out < sizeof(delta_head));
1363 git_inflate_end(&stream);
1364 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1365 error("delta data unpack-initial failed");
1366 return 0;
1367 }
1369 /* Examine the initial part of the delta to figure out
1370 * the result size.
1371 */
1372 data = delta_head;
1374 /* ignore base size */
1375 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1377 /* Read the result size */
1378 return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1379 }
1381 static off_t get_delta_base(struct packed_git *p,
1382 struct pack_window **w_curs,
1383 off_t *curpos,
1384 enum object_type type,
1385 off_t delta_obj_offset)
1386 {
1387 unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1388 off_t base_offset;
1390 /* use_pack() assured us we have [base_info, base_info + 20)
1391 * as a range that we can look at without walking off the
1392 * end of the mapped window. Its actually the hash size
1393 * that is assured. An OFS_DELTA longer than the hash size
1394 * is stupid, as then a REF_DELTA would be smaller to store.
1395 */
1396 if (type == OBJ_OFS_DELTA) {
1397 unsigned used = 0;
1398 unsigned char c = base_info[used++];
1399 base_offset = c & 127;
1400 while (c & 128) {
1401 base_offset += 1;
1402 if (!base_offset || MSB(base_offset, 7))
1403 return 0; /* overflow */
1404 c = base_info[used++];
1405 base_offset = (base_offset << 7) + (c & 127);
1406 }
1407 base_offset = delta_obj_offset - base_offset;
1408 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1409 return 0; /* out of bound */
1410 *curpos += used;
1411 } else if (type == OBJ_REF_DELTA) {
1412 /* The base entry _must_ be in the same pack */
1413 base_offset = find_pack_entry_one(base_info, p);
1414 *curpos += 20;
1415 } else
1416 die("I am totally screwed");
1417 return base_offset;
1418 }
1420 /* forward declaration for a mutually recursive function */
1421 static int packed_object_info(struct packed_git *p, off_t offset,
1422 unsigned long *sizep);
1424 static int packed_delta_info(struct packed_git *p,
1425 struct pack_window **w_curs,
1426 off_t curpos,
1427 enum object_type type,
1428 off_t obj_offset,
1429 unsigned long *sizep)
1430 {
1431 off_t base_offset;
1433 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1434 if (!base_offset)
1435 return OBJ_BAD;
1436 type = packed_object_info(p, base_offset, NULL);
1437 if (type <= OBJ_NONE) {
1438 struct revindex_entry *revidx;
1439 const unsigned char *base_sha1;
1440 revidx = find_pack_revindex(p, base_offset);
1441 if (!revidx)
1442 return OBJ_BAD;
1443 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1444 mark_bad_packed_object(p, base_sha1);
1445 type = sha1_object_info(base_sha1, NULL);
1446 if (type <= OBJ_NONE)
1447 return OBJ_BAD;
1448 }
1450 /* We choose to only get the type of the base object and
1451 * ignore potentially corrupt pack file that expects the delta
1452 * based on a base with a wrong size. This saves tons of
1453 * inflate() calls.
1454 */
1455 if (sizep) {
1456 *sizep = get_size_from_delta(p, w_curs, curpos);
1457 if (*sizep == 0)
1458 type = OBJ_BAD;
1459 }
1461 return type;
1462 }
1464 static int unpack_object_header(struct packed_git *p,
1465 struct pack_window **w_curs,
1466 off_t *curpos,
1467 unsigned long *sizep)
1468 {
1469 unsigned char *base;
1470 unsigned int left;
1471 unsigned long used;
1472 enum object_type type;
1474 /* use_pack() assures us we have [base, base + 20) available
1475 * as a range that we can look at at. (Its actually the hash
1476 * size that is assured.) With our object header encoding
1477 * the maximum deflated object size is 2^137, which is just
1478 * insane, so we know won't exceed what we have been given.
1479 */
1480 base = use_pack(p, w_curs, *curpos, &left);
1481 used = unpack_object_header_buffer(base, left, &type, sizep);
1482 if (!used) {
1483 type = OBJ_BAD;
1484 } else
1485 *curpos += used;
1487 return type;
1488 }
1490 const char *packed_object_info_detail(struct packed_git *p,
1491 off_t obj_offset,
1492 unsigned long *size,
1493 unsigned long *store_size,
1494 unsigned int *delta_chain_length,
1495 unsigned char *base_sha1)
1496 {
1497 struct pack_window *w_curs = NULL;
1498 off_t curpos;
1499 unsigned long dummy;
1500 unsigned char *next_sha1;
1501 enum object_type type;
1502 struct revindex_entry *revidx;
1504 *delta_chain_length = 0;
1505 curpos = obj_offset;
1506 type = unpack_object_header(p, &w_curs, &curpos, size);
1508 revidx = find_pack_revindex(p, obj_offset);
1509 *store_size = revidx[1].offset - obj_offset;
1511 for (;;) {
1512 switch (type) {
1513 default:
1514 die("pack %s contains unknown object type %d",
1515 p->pack_name, type);
1516 case OBJ_COMMIT:
1517 case OBJ_TREE:
1518 case OBJ_BLOB:
1519 case OBJ_TAG:
1520 unuse_pack(&w_curs);
1521 return typename(type);
1522 case OBJ_OFS_DELTA:
1523 obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1524 if (!obj_offset)
1525 die("pack %s contains bad delta base reference of type %s",
1526 p->pack_name, typename(type));
1527 if (*delta_chain_length == 0) {
1528 revidx = find_pack_revindex(p, obj_offset);
1529 hashcpy(base_sha1, nth_packed_object_sha1(p, revidx->nr));
1530 }
1531 break;
1532 case OBJ_REF_DELTA:
1533 next_sha1 = use_pack(p, &w_curs, curpos, NULL);
1534 if (*delta_chain_length == 0)
1535 hashcpy(base_sha1, next_sha1);
1536 obj_offset = find_pack_entry_one(next_sha1, p);
1537 break;
1538 }
1539 (*delta_chain_length)++;
1540 curpos = obj_offset;
1541 type = unpack_object_header(p, &w_curs, &curpos, &dummy);
1542 }
1543 }
1545 static int packed_object_info(struct packed_git *p, off_t obj_offset,
1546 unsigned long *sizep)
1547 {
1548 struct pack_window *w_curs = NULL;
1549 unsigned long size;
1550 off_t curpos = obj_offset;
1551 enum object_type type;
1553 type = unpack_object_header(p, &w_curs, &curpos, &size);
1555 switch (type) {
1556 case OBJ_OFS_DELTA:
1557 case OBJ_REF_DELTA:
1558 type = packed_delta_info(p, &w_curs, curpos,
1559 type, obj_offset, sizep);
1560 break;
1561 case OBJ_COMMIT:
1562 case OBJ_TREE:
1563 case OBJ_BLOB:
1564 case OBJ_TAG:
1565 if (sizep)
1566 *sizep = size;
1567 break;
1568 default:
1569 error("unknown object type %i at offset %"PRIuMAX" in %s",
1570 type, (uintmax_t)obj_offset, p->pack_name);
1571 type = OBJ_BAD;
1572 }
1573 unuse_pack(&w_curs);
1574 return type;
1575 }
1577 static void *unpack_compressed_entry(struct packed_git *p,
1578 struct pack_window **w_curs,
1579 off_t curpos,
1580 unsigned long size)
1581 {
1582 int st;
1583 z_stream stream;
1584 unsigned char *buffer, *in;
1586 buffer = xmalloc(size + 1);
1587 buffer[size] = 0;
1588 memset(&stream, 0, sizeof(stream));
1589 stream.next_out = buffer;
1590 stream.avail_out = size + 1;
1592 git_inflate_init(&stream);
1593 do {
1594 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1595 stream.next_in = in;
1596 st = git_inflate(&stream, Z_FINISH);
1597 if (!stream.avail_out)
1598 break; /* the payload is larger than it should be */
1599 curpos += stream.next_in - in;
1600 } while (st == Z_OK || st == Z_BUF_ERROR);
1601 git_inflate_end(&stream);
1602 if ((st != Z_STREAM_END) || stream.total_out != size) {
1603 free(buffer);
1604 return NULL;
1605 }
1607 return buffer;
1608 }
1610 #define MAX_DELTA_CACHE (256)
1612 static size_t delta_base_cached;
1614 static struct delta_base_cache_lru_list {
1615 struct delta_base_cache_lru_list *prev;
1616 struct delta_base_cache_lru_list *next;
1617 } delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
1619 static struct delta_base_cache_entry {
1620 struct delta_base_cache_lru_list lru;
1621 void *data;
1622 struct packed_git *p;
1623 off_t base_offset;
1624 unsigned long size;
1625 enum object_type type;
1626 } delta_base_cache[MAX_DELTA_CACHE];
1628 static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
1629 {
1630 unsigned long hash;
1632 hash = (unsigned long)p + (unsigned long)base_offset;
1633 hash += (hash >> 8) + (hash >> 16);
1634 return hash % MAX_DELTA_CACHE;
1635 }
1637 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1638 unsigned long *base_size, enum object_type *type, int keep_cache)
1639 {
1640 void *ret;
1641 unsigned long hash = pack_entry_hash(p, base_offset);
1642 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1644 ret = ent->data;
1645 if (!ret || ent->p != p || ent->base_offset != base_offset)
1646 return unpack_entry(p, base_offset, type, base_size);
1648 if (!keep_cache) {
1649 ent->data = NULL;
1650 ent->lru.next->prev = ent->lru.prev;
1651 ent->lru.prev->next = ent->lru.next;
1652 delta_base_cached -= ent->size;
1653 } else {
1654 ret = xmemdupz(ent->data, ent->size);
1655 }
1656 *type = ent->type;
1657 *base_size = ent->size;
1658 return ret;
1659 }
1661 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1662 {
1663 if (ent->data) {
1664 free(ent->data);
1665 ent->data = NULL;
1666 ent->lru.next->prev = ent->lru.prev;
1667 ent->lru.prev->next = ent->lru.next;
1668 delta_base_cached -= ent->size;
1669 }
1670 }
1672 void clear_delta_base_cache(void)
1673 {
1674 unsigned long p;
1675 for (p = 0; p < MAX_DELTA_CACHE; p++)
1676 release_delta_base_cache(&delta_base_cache[p]);
1677 }
1679 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1680 void *base, unsigned long base_size, enum object_type type)
1681 {
1682 unsigned long hash = pack_entry_hash(p, base_offset);
1683 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1684 struct delta_base_cache_lru_list *lru;
1686 release_delta_base_cache(ent);
1687 delta_base_cached += base_size;
1689 for (lru = delta_base_cache_lru.next;
1690 delta_base_cached > delta_base_cache_limit
1691 && lru != &delta_base_cache_lru;
1692 lru = lru->next) {
1693 struct delta_base_cache_entry *f = (void *)lru;
1694 if (f->type == OBJ_BLOB)
1695 release_delta_base_cache(f);
1696 }
1697 for (lru = delta_base_cache_lru.next;
1698 delta_base_cached > delta_base_cache_limit
1699 && lru != &delta_base_cache_lru;
1700 lru = lru->next) {
1701 struct delta_base_cache_entry *f = (void *)lru;
1702 release_delta_base_cache(f);
1703 }
1705 ent->p = p;
1706 ent->base_offset = base_offset;
1707 ent->type = type;
1708 ent->data = base;
1709 ent->size = base_size;
1710 ent->lru.next = &delta_base_cache_lru;
1711 ent->lru.prev = delta_base_cache_lru.prev;
1712 delta_base_cache_lru.prev->next = &ent->lru;
1713 delta_base_cache_lru.prev = &ent->lru;
1714 }
1716 static void *read_object(const unsigned char *sha1, enum object_type *type,
1717 unsigned long *size);
1719 static void *unpack_delta_entry(struct packed_git *p,
1720 struct pack_window **w_curs,
1721 off_t curpos,
1722 unsigned long delta_size,
1723 off_t obj_offset,
1724 enum object_type *type,
1725 unsigned long *sizep)
1726 {
1727 void *delta_data, *result, *base;
1728 unsigned long base_size;
1729 off_t base_offset;
1731 base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
1732 if (!base_offset) {
1733 error("failed to validate delta base reference "
1734 "at offset %"PRIuMAX" from %s",
1735 (uintmax_t)curpos, p->pack_name);
1736 return NULL;
1737 }
1738 unuse_pack(w_curs);
1739 base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
1740 if (!base) {
1741 /*
1742 * We're probably in deep shit, but let's try to fetch
1743 * the required base anyway from another pack or loose.
1744 * This is costly but should happen only in the presence
1745 * of a corrupted pack, and is better than failing outright.
1746 */
1747 struct revindex_entry *revidx;
1748 const unsigned char *base_sha1;
1749 revidx = find_pack_revindex(p, base_offset);
1750 if (!revidx)
1751 return NULL;
1752 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1753 error("failed to read delta base object %s"
1754 " at offset %"PRIuMAX" from %s",
1755 sha1_to_hex(base_sha1), (uintmax_t)base_offset,
1756 p->pack_name);
1757 mark_bad_packed_object(p, base_sha1);
1758 base = read_object(base_sha1, type, &base_size);
1759 if (!base)
1760 return NULL;
1761 }
1763 delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
1764 if (!delta_data) {
1765 error("failed to unpack compressed delta "
1766 "at offset %"PRIuMAX" from %s",
1767 (uintmax_t)curpos, p->pack_name);
1768 free(base);
1769 return NULL;
1770 }
1771 result = patch_delta(base, base_size,
1772 delta_data, delta_size,
1773 sizep);
1774 if (!result)
1775 die("failed to apply delta");
1776 free(delta_data);
1777 add_delta_base_cache(p, base_offset, base, base_size, *type);
1778 return result;
1779 }
1781 int do_check_packed_object_crc;
1783 void *unpack_entry(struct packed_git *p, off_t obj_offset,
1784 enum object_type *type, unsigned long *sizep)
1785 {
1786 struct pack_window *w_curs = NULL;
1787 off_t curpos = obj_offset;
1788 void *data;
1790 if (do_check_packed_object_crc && p->index_version > 1) {
1791 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1792 unsigned long len = revidx[1].offset - obj_offset;
1793 if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1794 const unsigned char *sha1 =
1795 nth_packed_object_sha1(p, revidx->nr);
1796 error("bad packed object CRC for %s",
1797 sha1_to_hex(sha1));
1798 mark_bad_packed_object(p, sha1);
1799 unuse_pack(&w_curs);
1800 return NULL;
1801 }
1802 }
1804 *type = unpack_object_header(p, &w_curs, &curpos, sizep);
1805 switch (*type) {
1806 case OBJ_OFS_DELTA:
1807 case OBJ_REF_DELTA:
1808 data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
1809 obj_offset, type, sizep);
1810 break;
1811 case OBJ_COMMIT:
1812 case OBJ_TREE:
1813 case OBJ_BLOB:
1814 case OBJ_TAG:
1815 data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
1816 break;
1817 default:
1818 data = NULL;
1819 error("unknown object type %i at offset %"PRIuMAX" in %s",
1820 *type, (uintmax_t)obj_offset, p->pack_name);
1821 }
1822 unuse_pack(&w_curs);
1823 return data;
1824 }
1826 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1827 uint32_t n)
1828 {
1829 const unsigned char *index = p->index_data;
1830 if (!index) {
1831 if (open_pack_index(p))
1832 return NULL;
1833 index = p->index_data;
1834 }
1835 if (n >= p->num_objects)
1836 return NULL;
1837 index += 4 * 256;
1838 if (p->index_version == 1) {
1839 return index + 24 * n + 4;
1840 } else {
1841 index += 8;
1842 return index + 20 * n;
1843 }
1844 }
1846 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1847 {
1848 const unsigned char *index = p->index_data;
1849 index += 4 * 256;
1850 if (p->index_version == 1) {
1851 return ntohl(*((uint32_t *)(index + 24 * n)));
1852 } else {
1853 uint32_t off;
1854 index += 8 + p->num_objects * (20 + 4);
1855 off = ntohl(*((uint32_t *)(index + 4 * n)));
1856 if (!(off & 0x80000000))
1857 return off;
1858 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1859 return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
1860 ntohl(*((uint32_t *)(index + 4)));
1861 }
1862 }
1864 off_t find_pack_entry_one(const unsigned char *sha1,
1865 struct packed_git *p)
1866 {
1867 const uint32_t *level1_ofs = p->index_data;
1868 const unsigned char *index = p->index_data;
1869 unsigned hi, lo, stride;
1870 static int use_lookup = -1;
1871 static int debug_lookup = -1;
1873 if (debug_lookup < 0)
1874 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
1876 if (!index) {
1877 if (open_pack_index(p))
1878 return 0;
1879 level1_ofs = p->index_data;
1880 index = p->index_data;
1881 }
1882 if (p->index_version > 1) {
1883 level1_ofs += 2;
1884 index += 8;
1885 }
1886 index += 4 * 256;
1887 hi = ntohl(level1_ofs[*sha1]);
1888 lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1889 if (p->index_version > 1) {
1890 stride = 20;
1891 } else {
1892 stride = 24;
1893 index += 4;
1894 }
1896 if (debug_lookup)
1897 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
1898 sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
1900 if (use_lookup < 0)
1901 use_lookup = !!getenv("GIT_USE_LOOKUP");
1902 if (use_lookup) {
1903 int pos = sha1_entry_pos(index, stride, 0,
1904 lo, hi, p->num_objects, sha1);
1905 if (pos < 0)
1906 return 0;
1907 return nth_packed_object_offset(p, pos);
1908 }
1910 do {
1911 unsigned mi = (lo + hi) / 2;
1912 int cmp = hashcmp(index + mi * stride, sha1);
1914 if (debug_lookup)
1915 printf("lo %u hi %u rg %u mi %u\n",
1916 lo, hi, hi - lo, mi);
1917 if (!cmp)
1918 return nth_packed_object_offset(p, mi);
1919 if (cmp > 0)
1920 hi = mi;
1921 else
1922 lo = mi+1;
1923 } while (lo < hi);
1924 return 0;
1925 }
1927 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1928 {
1929 static struct packed_git *last_found = (void *)1;
1930 struct packed_git *p;
1931 off_t offset;
1933 prepare_packed_git();
1934 if (!packed_git)
1935 return 0;
1936 p = (last_found == (void *)1) ? packed_git : last_found;
1938 do {
1939 if (p->num_bad_objects) {
1940 unsigned i;
1941 for (i = 0; i < p->num_bad_objects; i++)
1942 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1943 goto next;
1944 }
1946 offset = find_pack_entry_one(sha1, p);
1947 if (offset) {
1948 /*
1949 * We are about to tell the caller where they can
1950 * locate the requested object. We better make
1951 * sure the packfile is still here and can be
1952 * accessed before supplying that answer, as
1953 * it may have been deleted since the index
1954 * was loaded!
1955 */
1956 if (p->pack_fd == -1 && open_packed_git(p)) {
1957 error("packfile %s cannot be accessed", p->pack_name);
1958 goto next;
1959 }
1960 e->offset = offset;
1961 e->p = p;
1962 hashcpy(e->sha1, sha1);
1963 last_found = p;
1964 return 1;
1965 }
1967 next:
1968 if (p == last_found)
1969 p = packed_git;
1970 else
1971 p = p->next;
1972 if (p == last_found)
1973 p = p->next;
1974 } while (p);
1975 return 0;
1976 }
1978 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1979 struct packed_git *packs)
1980 {
1981 struct packed_git *p;
1983 for (p = packs; p; p = p->next) {
1984 if (find_pack_entry_one(sha1, p))
1985 return p;
1986 }
1987 return NULL;
1989 }
1991 static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
1992 {
1993 int status;
1994 unsigned long mapsize, size;
1995 void *map;
1996 z_stream stream;
1997 char hdr[32];
1999 map = map_sha1_file(sha1, &mapsize);
2000 if (!map)
2001 return error("unable to find %s", sha1_to_hex(sha1));
2002 if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2003 status = error("unable to unpack %s header",
2004 sha1_to_hex(sha1));
2005 else if ((status = parse_sha1_header(hdr, &size)) < 0)
2006 status = error("unable to parse %s header", sha1_to_hex(sha1));
2007 else if (sizep)
2008 *sizep = size;
2009 git_inflate_end(&stream);
2010 munmap(map, mapsize);
2011 return status;
2012 }
2014 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2015 {
2016 struct pack_entry e;
2017 int status;
2019 if (!find_pack_entry(sha1, &e)) {
2020 /* Most likely it's a loose object. */
2021 status = sha1_loose_object_info(sha1, sizep);
2022 if (status >= 0)
2023 return status;
2025 /* Not a loose object; someone else may have just packed it. */
2026 reprepare_packed_git();
2027 if (!find_pack_entry(sha1, &e))
2028 return status;
2029 }
2031 status = packed_object_info(e.p, e.offset, sizep);
2032 if (status < 0) {
2033 mark_bad_packed_object(e.p, sha1);
2034 status = sha1_object_info(sha1, sizep);
2035 }
2037 return status;
2038 }
2040 static void *read_packed_sha1(const unsigned char *sha1,
2041 enum object_type *type, unsigned long *size)
2042 {
2043 struct pack_entry e;
2044 void *data;
2046 if (!find_pack_entry(sha1, &e))
2047 return NULL;
2048 data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
2049 if (!data) {
2050 /*
2051 * We're probably in deep shit, but let's try to fetch
2052 * the required object anyway from another pack or loose.
2053 * This should happen only in the presence of a corrupted
2054 * pack, and is better than failing outright.
2055 */
2056 error("failed to read object %s at offset %"PRIuMAX" from %s",
2057 sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2058 mark_bad_packed_object(e.p, sha1);
2059 data = read_object(sha1, type, size);
2060 }
2061 return data;
2062 }
2064 /*
2065 * This is meant to hold a *small* number of objects that you would
2066 * want read_sha1_file() to be able to return, but yet you do not want
2067 * to write them into the object store (e.g. a browse-only
2068 * application).
2069 */
2070 static struct cached_object {
2071 unsigned char sha1[20];
2072 enum object_type type;
2073 void *buf;
2074 unsigned long size;
2075 } *cached_objects;
2076 static int cached_object_nr, cached_object_alloc;
2078 static struct cached_object empty_tree = {
2079 EMPTY_TREE_SHA1_BIN,
2080 OBJ_TREE,
2081 "",
2082 0
2083 };
2085 static struct cached_object *find_cached_object(const unsigned char *sha1)
2086 {
2087 int i;
2088 struct cached_object *co = cached_objects;
2090 for (i = 0; i < cached_object_nr; i++, co++) {
2091 if (!hashcmp(co->sha1, sha1))
2092 return co;
2093 }
2094 if (!hashcmp(sha1, empty_tree.sha1))
2095 return &empty_tree;
2096 return NULL;
2097 }
2099 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2100 unsigned char *sha1)
2101 {
2102 struct cached_object *co;
2104 hash_sha1_file(buf, len, typename(type), sha1);
2105 if (has_sha1_file(sha1) || find_cached_object(sha1))
2106 return 0;
2107 if (cached_object_alloc <= cached_object_nr) {
2108 cached_object_alloc = alloc_nr(cached_object_alloc);
2109 cached_objects = xrealloc(cached_objects,
2110 sizeof(*cached_objects) *
2111 cached_object_alloc);
2112 }
2113 co = &cached_objects[cached_object_nr++];
2114 co->size = len;
2115 co->type = type;
2116 co->buf = xmalloc(len);
2117 memcpy(co->buf, buf, len);
2118 hashcpy(co->sha1, sha1);
2119 return 0;
2120 }
2122 static void *read_object(const unsigned char *sha1, enum object_type *type,
2123 unsigned long *size)
2124 {
2125 unsigned long mapsize;
2126 void *map, *buf;
2127 struct cached_object *co;
2129 co = find_cached_object(sha1);
2130 if (co) {
2131 *type = co->type;
2132 *size = co->size;
2133 return xmemdupz(co->buf, co->size);
2134 }
2136 buf = read_packed_sha1(sha1, type, size);
2137 if (buf)
2138 return buf;
2139 map = map_sha1_file(sha1, &mapsize);
2140 if (map) {
2141 buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2142 munmap(map, mapsize);
2143 return buf;
2144 }
2145 reprepare_packed_git();
2146 return read_packed_sha1(sha1, type, size);
2147 }
2149 void *read_sha1_file_repl(const unsigned char *sha1,
2150 enum object_type *type,
2151 unsigned long *size,
2152 const unsigned char **replacement)
2153 {
2154 const unsigned char *repl = lookup_replace_object(sha1);
2155 void *data = read_object(repl, type, size);
2157 /* die if we replaced an object with one that does not exist */
2158 if (!data && repl != sha1)
2159 die("replacement %s not found for %s",
2160 sha1_to_hex(repl), sha1_to_hex(sha1));
2162 /* legacy behavior is to die on corrupted objects */
2163 if (!data && (has_loose_object(repl) || has_packed_and_bad(repl)))
2164 die("object %s is corrupted", sha1_to_hex(repl));
2166 if (replacement)
2167 *replacement = repl;
2169 return data;
2170 }
2172 void *read_object_with_reference(const unsigned char *sha1,
2173 const char *required_type_name,
2174 unsigned long *size,
2175 unsigned char *actual_sha1_return)
2176 {
2177 enum object_type type, required_type;
2178 void *buffer;
2179 unsigned long isize;
2180 unsigned char actual_sha1[20];
2182 required_type = type_from_string(required_type_name);
2183 hashcpy(actual_sha1, sha1);
2184 while (1) {
2185 int ref_length = -1;
2186 const char *ref_type = NULL;
2188 buffer = read_sha1_file(actual_sha1, &type, &isize);
2189 if (!buffer)
2190 return NULL;
2191 if (type == required_type) {
2192 *size = isize;
2193 if (actual_sha1_return)
2194 hashcpy(actual_sha1_return, actual_sha1);
2195 return buffer;
2196 }
2197 /* Handle references */
2198 else if (type == OBJ_COMMIT)
2199 ref_type = "tree ";
2200 else if (type == OBJ_TAG)
2201 ref_type = "object ";
2202 else {
2203 free(buffer);
2204 return NULL;
2205 }
2206 ref_length = strlen(ref_type);
2208 if (ref_length + 40 > isize ||
2209 memcmp(buffer, ref_type, ref_length) ||
2210 get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2211 free(buffer);
2212 return NULL;
2213 }
2214 free(buffer);
2215 /* Now we have the ID of the referred-to object in
2216 * actual_sha1. Check again. */
2217 }
2218 }
2220 static void write_sha1_file_prepare(const void *buf, unsigned long len,
2221 const char *type, unsigned char *sha1,
2222 char *hdr, int *hdrlen)
2223 {
2224 git_SHA_CTX c;
2226 /* Generate the header */
2227 *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
2229 /* Sha1.. */
2230 git_SHA1_Init(&c);
2231 git_SHA1_Update(&c, hdr, *hdrlen);
2232 git_SHA1_Update(&c, buf, len);
2233 git_SHA1_Final(sha1, &c);
2234 }
2236 /*
2237 * Move the just written object into its final resting place.
2238 * NEEDSWORK: this should be renamed to finalize_temp_file() as
2239 * "moving" is only a part of what it does, when no patch between
2240 * master to pu changes the call sites of this function.
2241 */
2242 int move_temp_to_file(const char *tmpfile, const char *filename)
2243 {
2244 int ret = 0;
2246 if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2247 goto try_rename;
2248 else if (link(tmpfile, filename))
2249 ret = errno;
2251 /*
2252 * Coda hack - coda doesn't like cross-directory links,
2253 * so we fall back to a rename, which will mean that it
2254 * won't be able to check collisions, but that's not a
2255 * big deal.
2256 *
2257 * The same holds for FAT formatted media.
2258 *
2259 * When this succeeds, we just return. We have nothing
2260 * left to unlink.
2261 */
2262 if (ret && ret != EEXIST) {
2263 try_rename:
2264 if (!rename(tmpfile, filename))
2265 goto out;
2266 ret = errno;
2267 }
2268 unlink_or_warn(tmpfile);
2269 if (ret) {
2270 if (ret != EEXIST) {
2271 return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
2272 }
2273 /* FIXME!!! Collision check here ? */
2274 }
2276 out:
2277 if (set_shared_perm(filename, (S_IFREG|0444)))
2278 return error("unable to set permission to '%s'", filename);
2279 return 0;
2280 }
2282 static int write_buffer(int fd, const void *buf, size_t len)
2283 {
2284 if (write_in_full(fd, buf, len) < 0)
2285 return error("file write error (%s)", strerror(errno));
2286 return 0;
2287 }
2289 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2290 unsigned char *sha1)
2291 {
2292 char hdr[32];
2293 int hdrlen;
2294 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2295 return 0;
2296 }
2298 /* Finalize a file on disk, and close it. */
2299 static void close_sha1_file(int fd)
2300 {
2301 if (fsync_object_files)
2302 fsync_or_die(fd, "sha1 file");
2303 if (close(fd) != 0)
2304 die_errno("error when closing sha1 file");
2305 }
2307 /* Size of directory component, including the ending '/' */
2308 static inline int directory_size(const char *filename)
2309 {
2310 const char *s = strrchr(filename, '/');
2311 if (!s)
2312 return 0;
2313 return s - filename + 1;
2314 }
2316 /*
2317 * This creates a temporary file in the same directory as the final
2318 * 'filename'
2319 *
2320 * We want to avoid cross-directory filename renames, because those
2321 * can have problems on various filesystems (FAT, NFS, Coda).
2322 */
2323 static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
2324 {
2325 int fd, dirlen = directory_size(filename);
2327 if (dirlen + 20 > bufsiz) {
2328 errno = ENAMETOOLONG;
2329 return -1;
2330 }
2331 memcpy(buffer, filename, dirlen);
2332 strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
2333 fd = mkstemp(buffer);
2334 if (fd < 0 && dirlen && errno == ENOENT) {
2335 /* Make sure the directory exists */
2336 memcpy(buffer, filename, dirlen);
2337 buffer[dirlen-1] = 0;
2338 if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
2339 return -1;
2341 /* Try again */
2342 strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
2343 fd = mkstemp(buffer);
2344 }
2345 return fd;
2346 }
2348 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
2349 void *buf, unsigned long len, time_t mtime)
2350 {
2351 int fd, ret;
2352 size_t size;
2353 unsigned char *compressed;
2354 z_stream stream;
2355 char *filename;
2356 static char tmpfile[PATH_MAX];
2358 filename = sha1_file_name(sha1);
2359 fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
2360 while (fd < 0 && errno == EMFILE && unuse_one_window(packed_git, -1))
2361 fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
2362 if (fd < 0) {
2363 if (errno == EACCES)
2364 return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
2365 else
2366 return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
2367 }
2369 /* Set it up */
2370 memset(&stream, 0, sizeof(stream));
2371 deflateInit(&stream, zlib_compression_level);
2372 size = 8 + deflateBound(&stream, len+hdrlen);
2373 compressed = xmalloc(size);
2375 /* Compress it */
2376 stream.next_out = compressed;
2377 stream.avail_out = size;
2379 /* First header.. */
2380 stream.next_in = (unsigned char *)hdr;
2381 stream.avail_in = hdrlen;
2382 while (deflate(&stream, 0) == Z_OK)
2383 /* nothing */;
2385 /* Then the data itself.. */
2386 stream.next_in = buf;
2387 stream.avail_in = len;
2388 ret = deflate(&stream, Z_FINISH);
2389 if (ret != Z_STREAM_END)
2390 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
2392 ret = deflateEnd(&stream);
2393 if (ret != Z_OK)
2394 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
2396 size = stream.total_out;
2398 if (write_buffer(fd, compressed, size) < 0)
2399 die("unable to write sha1 file");
2400 close_sha1_file(fd);
2401 free(compressed);
2403 if (mtime) {
2404 struct utimbuf utb;
2405 utb.actime = mtime;
2406 utb.modtime = mtime;
2407 if (utime(tmpfile, &utb) < 0)
2408 warning("failed utime() on %s: %s",
2409 tmpfile, strerror(errno));
2410 }
2412 return move_temp_to_file(tmpfile, filename);
2413 }
2415 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
2416 {
2417 unsigned char sha1[20];
2418 char hdr[32];
2419 int hdrlen;
2421 /* Normally if we have it in the pack then we do not bother writing
2422 * it out into .git/objects/??/?{38} file.
2423 */
2424 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2425 if (returnsha1)
2426 hashcpy(returnsha1, sha1);
2427 if (has_sha1_file(sha1))
2428 return 0;
2429 return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
2430 }
2432 int force_object_loose(const unsigned char *sha1, time_t mtime)
2433 {
2434 void *buf;
2435 unsigned long len;
2436 enum object_type type;
2437 char hdr[32];
2438 int hdrlen;
2439 int ret;
2441 if (has_loose_object(sha1))
2442 return 0;
2443 buf = read_packed_sha1(sha1, &type, &len);
2444 if (!buf)
2445 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
2446 hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
2447 ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
2448 free(buf);
2450 return ret;
2451 }
2453 int has_pack_index(const unsigned char *sha1)
2454 {
2455 struct stat st;
2456 if (stat(sha1_pack_index_name(sha1), &st))
2457 return 0;
2458 return 1;
2459 }
2461 int has_pack_file(const unsigned char *sha1)
2462 {
2463 struct stat st;
2464 if (stat(sha1_pack_name(sha1), &st))
2465 return 0;
2466 return 1;
2467 }
2469 int has_sha1_pack(const unsigned char *sha1)
2470 {
2471 struct pack_entry e;
2472 return find_pack_entry(sha1, &e);
2473 }
2475 int has_sha1_file(const unsigned char *sha1)
2476 {
2477 struct pack_entry e;
2479 if (find_pack_entry(sha1, &e))
2480 return 1;
2481 return has_loose_object(sha1);
2482 }
2484 static int index_mem(unsigned char *sha1, void *buf, size_t size,
2485 int write_object, enum object_type type, const char *path)
2486 {
2487 int ret, re_allocated = 0;
2489 if (!type)
2490 type = OBJ_BLOB;
2492 /*
2493 * Convert blobs to git internal format
2494 */
2495 if ((type == OBJ_BLOB) && path) {
2496 struct strbuf nbuf = STRBUF_INIT;
2497 if (convert_to_git(path, buf, size, &nbuf,
2498 write_object ? safe_crlf : 0)) {
2499 buf = strbuf_detach(&nbuf, &size);
2500 re_allocated = 1;
2501 }
2502 }
2504 if (write_object)
2505 ret = write_sha1_file(buf, size, typename(type), sha1);
2506 else
2507 ret = hash_sha1_file(buf, size, typename(type), sha1);
2508 if (re_allocated)
2509 free(buf);
2510 return ret;
2511 }
2513 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
2514 enum object_type type, const char *path)
2515 {
2516 int ret;
2517 size_t size = xsize_t(st->st_size);
2519 if (!S_ISREG(st->st_mode)) {
2520 struct strbuf sbuf = STRBUF_INIT;
2521 if (strbuf_read(&sbuf, fd, 4096) >= 0)
2522 ret = index_mem(sha1, sbuf.buf, sbuf.len, write_object,
2523 type, path);
2524 else
2525 ret = -1;
2526 strbuf_release(&sbuf);
2527 } else if (size) {
2528 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2529 ret = index_mem(sha1, buf, size, write_object, type, path);
2530 munmap(buf, size);
2531 } else
2532 ret = index_mem(sha1, NULL, size, write_object, type, path);
2533 close(fd);
2534 return ret;
2535 }
2537 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
2538 {
2539 int fd;
2540 struct strbuf sb = STRBUF_INIT;
2542 switch (st->st_mode & S_IFMT) {
2543 case S_IFREG:
2544 fd = open(path, O_RDONLY);
2545 if (fd < 0)
2546 return error("open(\"%s\"): %s", path,
2547 strerror(errno));
2548 if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
2549 return error("%s: failed to insert into database",
2550 path);
2551 break;
2552 case S_IFLNK:
2553 if (strbuf_readlink(&sb, path, st->st_size)) {
2554 char *errstr = strerror(errno);
2555 return error("readlink(\"%s\"): %s", path,
2556 errstr);
2557 }
2558 if (!write_object)
2559 hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
2560 else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
2561 return error("%s: failed to insert into database",
2562 path);
2563 strbuf_release(&sb);
2564 break;
2565 case S_IFDIR:
2566 return resolve_gitlink_ref(path, "HEAD", sha1);
2567 default:
2568 return error("%s: unsupported file type", path);
2569 }
2570 return 0;
2571 }
2573 int read_pack_header(int fd, struct pack_header *header)
2574 {
2575 if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
2576 /* "eof before pack header was fully read" */
2577 return PH_ERROR_EOF;
2579 if (header->hdr_signature != htonl(PACK_SIGNATURE))
2580 /* "protocol error (pack signature mismatch detected)" */
2581 return PH_ERROR_PACK_SIGNATURE;
2582 if (!pack_version_ok(header->hdr_version))
2583 /* "protocol error (pack version unsupported)" */
2584 return PH_ERROR_PROTOCOL;
2585 return 0;
2586 }