move encode_in_pack_object_header() to a better place
[git/git.git] / sha1_file.c
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"
19
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
27
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
35
36 const unsigned char null_sha1[20];
37
38 static inline int offset_1st_component(const char *path)
39 {
40 if (has_dos_drive_prefix(path))
41 return 2 + (path[2] == '/');
42 return *path == '/';
43 }
44
45 int safe_create_leading_directories(char *path)
46 {
47 char *pos = path + offset_1st_component(path);
48 struct stat st;
49
50 while (pos) {
51 pos = strchr(pos, '/');
52 if (!pos)
53 break;
54 while (*++pos == '/')
55 ;
56 if (!*pos)
57 break;
58 *--pos = '\0';
59 if (!stat(path, &st)) {
60 /* path exists */
61 if (!S_ISDIR(st.st_mode)) {
62 *pos = '/';
63 return -3;
64 }
65 }
66 else if (mkdir(path, 0777)) {
67 *pos = '/';
68 return -1;
69 }
70 else if (adjust_shared_perm(path)) {
71 *pos = '/';
72 return -2;
73 }
74 *pos++ = '/';
75 }
76 return 0;
77 }
78
79 int safe_create_leading_directories_const(const char *path)
80 {
81 /* path points to cache entries, so xstrdup before messing with it */
82 char *buf = xstrdup(path);
83 int result = safe_create_leading_directories(buf);
84 free(buf);
85 return result;
86 }
87
88 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
89 {
90 int i;
91 for (i = 0; i < 20; i++) {
92 static char hex[] = "0123456789abcdef";
93 unsigned int val = sha1[i];
94 char *pos = pathbuf + i*2 + (i > 0);
95 *pos++ = hex[val >> 4];
96 *pos = hex[val & 0xf];
97 }
98 }
99
100 /*
101 * NOTE! This returns a statically allocated buffer, so you have to be
102 * careful about using it. Do an "xstrdup()" if you need to save the
103 * filename.
104 *
105 * Also note that this returns the location for creating. Reading
106 * SHA1 file can happen from any alternate directory listed in the
107 * DB_ENVIRONMENT environment variable if it is not found in
108 * the primary object database.
109 */
110 char *sha1_file_name(const unsigned char *sha1)
111 {
112 static char *name, *base;
113
114 if (!base) {
115 const char *sha1_file_directory = get_object_directory();
116 int len = strlen(sha1_file_directory);
117 base = xmalloc(len + 60);
118 memcpy(base, sha1_file_directory, len);
119 memset(base+len, 0, 60);
120 base[len] = '/';
121 base[len+3] = '/';
122 name = base + len + 1;
123 }
124 fill_sha1_path(name, sha1);
125 return base;
126 }
127
128 static char *sha1_get_pack_name(const unsigned char *sha1,
129 char **name, char **base, const char *which)
130 {
131 static const char hex[] = "0123456789abcdef";
132 char *buf;
133 int i;
134
135 if (!*base) {
136 const char *sha1_file_directory = get_object_directory();
137 int len = strlen(sha1_file_directory);
138 *base = xmalloc(len + 60);
139 sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
140 sha1_file_directory, which);
141 *name = *base + len + 11;
142 }
143
144 buf = *name;
145
146 for (i = 0; i < 20; i++) {
147 unsigned int val = *sha1++;
148 *buf++ = hex[val >> 4];
149 *buf++ = hex[val & 0xf];
150 }
151
152 return *base;
153 }
154
155 char *sha1_pack_name(const unsigned char *sha1)
156 {
157 static char *name, *base;
158
159 return sha1_get_pack_name(sha1, &name, &base, "pack");
160 }
161
162 char *sha1_pack_index_name(const unsigned char *sha1)
163 {
164 static char *name, *base;
165
166 return sha1_get_pack_name(sha1, &name, &base, "idx");
167 }
168
169 struct alternate_object_database *alt_odb_list;
170 static struct alternate_object_database **alt_odb_tail;
171
172 static void read_info_alternates(const char * alternates, int depth);
173
174 /*
175 * Prepare alternate object database registry.
176 *
177 * The variable alt_odb_list points at the list of struct
178 * alternate_object_database. The elements on this list come from
179 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
180 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
181 * whose contents is similar to that environment variable but can be
182 * LF separated. Its base points at a statically allocated buffer that
183 * contains "/the/directory/corresponding/to/.git/objects/...", while
184 * its name points just after the slash at the end of ".git/objects/"
185 * in the example above, and has enough space to hold 40-byte hex
186 * SHA1, an extra slash for the first level indirection, and the
187 * terminating NUL.
188 */
189 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
190 {
191 const char *objdir = get_object_directory();
192 struct alternate_object_database *ent;
193 struct alternate_object_database *alt;
194 /* 43 = 40-byte + 2 '/' + terminating NUL */
195 int pfxlen = len;
196 int entlen = pfxlen + 43;
197 int base_len = -1;
198
199 if (!is_absolute_path(entry) && relative_base) {
200 /* Relative alt-odb */
201 if (base_len < 0)
202 base_len = strlen(relative_base) + 1;
203 entlen += base_len;
204 pfxlen += base_len;
205 }
206 ent = xmalloc(sizeof(*ent) + entlen);
207
208 if (!is_absolute_path(entry) && relative_base) {
209 memcpy(ent->base, relative_base, base_len - 1);
210 ent->base[base_len - 1] = '/';
211 memcpy(ent->base + base_len, entry, len);
212 }
213 else
214 memcpy(ent->base, entry, pfxlen);
215
216 ent->name = ent->base + pfxlen + 1;
217 ent->base[pfxlen + 3] = '/';
218 ent->base[pfxlen] = ent->base[entlen-1] = 0;
219
220 /* Detect cases where alternate disappeared */
221 if (!is_directory(ent->base)) {
222 error("object directory %s does not exist; "
223 "check .git/objects/info/alternates.",
224 ent->base);
225 free(ent);
226 return -1;
227 }
228
229 /* Prevent the common mistake of listing the same
230 * thing twice, or object directory itself.
231 */
232 for (alt = alt_odb_list; alt; alt = alt->next) {
233 if (!memcmp(ent->base, alt->base, pfxlen)) {
234 free(ent);
235 return -1;
236 }
237 }
238 if (!memcmp(ent->base, objdir, pfxlen)) {
239 free(ent);
240 return -1;
241 }
242
243 /* add the alternate entry */
244 *alt_odb_tail = ent;
245 alt_odb_tail = &(ent->next);
246 ent->next = NULL;
247
248 /* recursively add alternates */
249 read_info_alternates(ent->base, depth + 1);
250
251 ent->base[pfxlen] = '/';
252
253 return 0;
254 }
255
256 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
257 const char *relative_base, int depth)
258 {
259 const char *cp, *last;
260
261 if (depth > 5) {
262 error("%s: ignoring alternate object stores, nesting too deep.",
263 relative_base);
264 return;
265 }
266
267 last = alt;
268 while (last < ep) {
269 cp = last;
270 if (cp < ep && *cp == '#') {
271 while (cp < ep && *cp != sep)
272 cp++;
273 last = cp + 1;
274 continue;
275 }
276 while (cp < ep && *cp != sep)
277 cp++;
278 if (last != cp) {
279 if (!is_absolute_path(last) && depth) {
280 error("%s: ignoring relative alternate object store %s",
281 relative_base, last);
282 } else {
283 link_alt_odb_entry(last, cp - last,
284 relative_base, depth);
285 }
286 }
287 while (cp < ep && *cp == sep)
288 cp++;
289 last = cp;
290 }
291 }
292
293 static void read_info_alternates(const char * relative_base, int depth)
294 {
295 char *map;
296 size_t mapsz;
297 struct stat st;
298 const char alt_file_name[] = "info/alternates";
299 /* Given that relative_base is no longer than PATH_MAX,
300 ensure that "path" has enough space to append "/", the
301 file name, "info/alternates", and a trailing NUL. */
302 char path[PATH_MAX + 1 + sizeof alt_file_name];
303 int fd;
304
305 sprintf(path, "%s/%s", relative_base, alt_file_name);
306 fd = open(path, O_RDONLY);
307 if (fd < 0)
308 return;
309 if (fstat(fd, &st) || (st.st_size == 0)) {
310 close(fd);
311 return;
312 }
313 mapsz = xsize_t(st.st_size);
314 map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
315 close(fd);
316
317 link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth);
318
319 munmap(map, mapsz);
320 }
321
322 void add_to_alternates_file(const char *reference)
323 {
324 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
325 int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR);
326 char *alt = mkpath("%s/objects\n", reference);
327 write_or_die(fd, alt, strlen(alt));
328 if (commit_lock_file(lock))
329 die("could not close alternates file");
330 if (alt_odb_tail)
331 link_alt_odb_entries(alt, alt + strlen(alt), '\n', NULL, 0);
332 }
333
334 void foreach_alt_odb(alt_odb_fn fn, void *cb)
335 {
336 struct alternate_object_database *ent;
337
338 prepare_alt_odb();
339 for (ent = alt_odb_list; ent; ent = ent->next)
340 if (fn(ent, cb))
341 return;
342 }
343
344 void prepare_alt_odb(void)
345 {
346 const char *alt;
347
348 if (alt_odb_tail)
349 return;
350
351 alt = getenv(ALTERNATE_DB_ENVIRONMENT);
352 if (!alt) alt = "";
353
354 alt_odb_tail = &alt_odb_list;
355 link_alt_odb_entries(alt, alt + strlen(alt), PATH_SEP, NULL, 0);
356
357 read_info_alternates(get_object_directory(), 0);
358 }
359
360 static int has_loose_object_local(const unsigned char *sha1)
361 {
362 char *name = sha1_file_name(sha1);
363 return !access(name, F_OK);
364 }
365
366 int has_loose_object_nonlocal(const unsigned char *sha1)
367 {
368 struct alternate_object_database *alt;
369 prepare_alt_odb();
370 for (alt = alt_odb_list; alt; alt = alt->next) {
371 fill_sha1_path(alt->name, sha1);
372 if (!access(alt->base, F_OK))
373 return 1;
374 }
375 return 0;
376 }
377
378 static int has_loose_object(const unsigned char *sha1)
379 {
380 return has_loose_object_local(sha1) ||
381 has_loose_object_nonlocal(sha1);
382 }
383
384 static unsigned int pack_used_ctr;
385 static unsigned int pack_mmap_calls;
386 static unsigned int peak_pack_open_windows;
387 static unsigned int pack_open_windows;
388 static size_t peak_pack_mapped;
389 static size_t pack_mapped;
390 struct packed_git *packed_git;
391
392 void pack_report(void)
393 {
394 fprintf(stderr,
395 "pack_report: getpagesize() = %10" SZ_FMT "\n"
396 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
397 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
398 sz_fmt(getpagesize()),
399 sz_fmt(packed_git_window_size),
400 sz_fmt(packed_git_limit));
401 fprintf(stderr,
402 "pack_report: pack_used_ctr = %10u\n"
403 "pack_report: pack_mmap_calls = %10u\n"
404 "pack_report: pack_open_windows = %10u / %10u\n"
405 "pack_report: pack_mapped = "
406 "%10" SZ_FMT " / %10" SZ_FMT "\n",
407 pack_used_ctr,
408 pack_mmap_calls,
409 pack_open_windows, peak_pack_open_windows,
410 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
411 }
412
413 static int check_packed_git_idx(const char *path, struct packed_git *p)
414 {
415 void *idx_map;
416 struct pack_idx_header *hdr;
417 size_t idx_size;
418 uint32_t version, nr, i, *index;
419 int fd = open(path, O_RDONLY);
420 struct stat st;
421
422 if (fd < 0)
423 return -1;
424 if (fstat(fd, &st)) {
425 close(fd);
426 return -1;
427 }
428 idx_size = xsize_t(st.st_size);
429 if (idx_size < 4 * 256 + 20 + 20) {
430 close(fd);
431 return error("index file %s is too small", path);
432 }
433 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
434 close(fd);
435
436 hdr = idx_map;
437 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
438 version = ntohl(hdr->idx_version);
439 if (version < 2 || version > 2) {
440 munmap(idx_map, idx_size);
441 return error("index file %s is version %"PRIu32
442 " and is not supported by this binary"
443 " (try upgrading GIT to a newer version)",
444 path, version);
445 }
446 } else
447 version = 1;
448
449 nr = 0;
450 index = idx_map;
451 if (version > 1)
452 index += 2; /* skip index header */
453 for (i = 0; i < 256; i++) {
454 uint32_t n = ntohl(index[i]);
455 if (n < nr) {
456 munmap(idx_map, idx_size);
457 return error("non-monotonic index %s", path);
458 }
459 nr = n;
460 }
461
462 if (version == 1) {
463 /*
464 * Total size:
465 * - 256 index entries 4 bytes each
466 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
467 * - 20-byte SHA1 of the packfile
468 * - 20-byte SHA1 file checksum
469 */
470 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
471 munmap(idx_map, idx_size);
472 return error("wrong index v1 file size in %s", path);
473 }
474 } else if (version == 2) {
475 /*
476 * Minimum size:
477 * - 8 bytes of header
478 * - 256 index entries 4 bytes each
479 * - 20-byte sha1 entry * nr
480 * - 4-byte crc entry * nr
481 * - 4-byte offset entry * nr
482 * - 20-byte SHA1 of the packfile
483 * - 20-byte SHA1 file checksum
484 * And after the 4-byte offset table might be a
485 * variable sized table containing 8-byte entries
486 * for offsets larger than 2^31.
487 */
488 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
489 unsigned long max_size = min_size;
490 if (nr)
491 max_size += (nr - 1)*8;
492 if (idx_size < min_size || idx_size > max_size) {
493 munmap(idx_map, idx_size);
494 return error("wrong index v2 file size in %s", path);
495 }
496 if (idx_size != min_size &&
497 /*
498 * make sure we can deal with large pack offsets.
499 * 31-bit signed offset won't be enough, neither
500 * 32-bit unsigned one will be.
501 */
502 (sizeof(off_t) <= 4)) {
503 munmap(idx_map, idx_size);
504 return error("pack too large for current definition of off_t in %s", path);
505 }
506 }
507
508 p->index_version = version;
509 p->index_data = idx_map;
510 p->index_size = idx_size;
511 p->num_objects = nr;
512 return 0;
513 }
514
515 int open_pack_index(struct packed_git *p)
516 {
517 char *idx_name;
518 int ret;
519
520 if (p->index_data)
521 return 0;
522
523 idx_name = xstrdup(p->pack_name);
524 strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
525 ret = check_packed_git_idx(idx_name, p);
526 free(idx_name);
527 return ret;
528 }
529
530 static void scan_windows(struct packed_git *p,
531 struct packed_git **lru_p,
532 struct pack_window **lru_w,
533 struct pack_window **lru_l)
534 {
535 struct pack_window *w, *w_l;
536
537 for (w_l = NULL, w = p->windows; w; w = w->next) {
538 if (!w->inuse_cnt) {
539 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
540 *lru_p = p;
541 *lru_w = w;
542 *lru_l = w_l;
543 }
544 }
545 w_l = w;
546 }
547 }
548
549 static int unuse_one_window(struct packed_git *current, int keep_fd)
550 {
551 struct packed_git *p, *lru_p = NULL;
552 struct pack_window *lru_w = NULL, *lru_l = NULL;
553
554 if (current)
555 scan_windows(current, &lru_p, &lru_w, &lru_l);
556 for (p = packed_git; p; p = p->next)
557 scan_windows(p, &lru_p, &lru_w, &lru_l);
558 if (lru_p) {
559 munmap(lru_w->base, lru_w->len);
560 pack_mapped -= lru_w->len;
561 if (lru_l)
562 lru_l->next = lru_w->next;
563 else {
564 lru_p->windows = lru_w->next;
565 if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
566 close(lru_p->pack_fd);
567 lru_p->pack_fd = -1;
568 }
569 }
570 free(lru_w);
571 pack_open_windows--;
572 return 1;
573 }
574 return 0;
575 }
576
577 void release_pack_memory(size_t need, int fd)
578 {
579 size_t cur = pack_mapped;
580 while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd))
581 ; /* nothing */
582 }
583
584 void close_pack_windows(struct packed_git *p)
585 {
586 while (p->windows) {
587 struct pack_window *w = p->windows;
588
589 if (w->inuse_cnt)
590 die("pack '%s' still has open windows to it",
591 p->pack_name);
592 munmap(w->base, w->len);
593 pack_mapped -= w->len;
594 pack_open_windows--;
595 p->windows = w->next;
596 free(w);
597 }
598 }
599
600 void unuse_pack(struct pack_window **w_cursor)
601 {
602 struct pack_window *w = *w_cursor;
603 if (w) {
604 w->inuse_cnt--;
605 *w_cursor = NULL;
606 }
607 }
608
609 /*
610 * This is used by git-repack in case a newly created pack happens to
611 * contain the same set of objects as an existing one. In that case
612 * the resulting file might be different even if its name would be the
613 * same. It is best to close any reference to the old pack before it is
614 * replaced on disk. Of course no index pointers nor windows for given pack
615 * must subsist at this point. If ever objects from this pack are requested
616 * again, the new version of the pack will be reinitialized through
617 * reprepare_packed_git().
618 */
619 void free_pack_by_name(const char *pack_name)
620 {
621 struct packed_git *p, **pp = &packed_git;
622
623 while (*pp) {
624 p = *pp;
625 if (strcmp(pack_name, p->pack_name) == 0) {
626 clear_delta_base_cache();
627 close_pack_windows(p);
628 if (p->pack_fd != -1)
629 close(p->pack_fd);
630 if (p->index_data)
631 munmap((void *)p->index_data, p->index_size);
632 free(p->bad_object_sha1);
633 *pp = p->next;
634 free(p);
635 return;
636 }
637 pp = &p->next;
638 }
639 }
640
641 /*
642 * Do not call this directly as this leaks p->pack_fd on error return;
643 * call open_packed_git() instead.
644 */
645 static int open_packed_git_1(struct packed_git *p)
646 {
647 struct stat st;
648 struct pack_header hdr;
649 unsigned char sha1[20];
650 unsigned char *idx_sha1;
651 long fd_flag;
652
653 if (!p->index_data && open_pack_index(p))
654 return error("packfile %s index unavailable", p->pack_name);
655
656 p->pack_fd = open(p->pack_name, O_RDONLY);
657 while (p->pack_fd < 0 && errno == EMFILE && unuse_one_window(p, -1))
658 p->pack_fd = open(p->pack_name, O_RDONLY);
659 if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
660 return -1;
661
662 /* If we created the struct before we had the pack we lack size. */
663 if (!p->pack_size) {
664 if (!S_ISREG(st.st_mode))
665 return error("packfile %s not a regular file", p->pack_name);
666 p->pack_size = st.st_size;
667 } else if (p->pack_size != st.st_size)
668 return error("packfile %s size changed", p->pack_name);
669
670 /* We leave these file descriptors open with sliding mmap;
671 * there is no point keeping them open across exec(), though.
672 */
673 fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
674 if (fd_flag < 0)
675 return error("cannot determine file descriptor flags");
676 fd_flag |= FD_CLOEXEC;
677 if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
678 return error("cannot set FD_CLOEXEC");
679
680 /* Verify we recognize this pack file format. */
681 if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
682 return error("file %s is far too short to be a packfile", p->pack_name);
683 if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
684 return error("file %s is not a GIT packfile", p->pack_name);
685 if (!pack_version_ok(hdr.hdr_version))
686 return error("packfile %s is version %"PRIu32" and not"
687 " supported (try upgrading GIT to a newer version)",
688 p->pack_name, ntohl(hdr.hdr_version));
689
690 /* Verify the pack matches its index. */
691 if (p->num_objects != ntohl(hdr.hdr_entries))
692 return error("packfile %s claims to have %"PRIu32" objects"
693 " while index indicates %"PRIu32" objects",
694 p->pack_name, ntohl(hdr.hdr_entries),
695 p->num_objects);
696 if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
697 return error("end of packfile %s is unavailable", p->pack_name);
698 if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
699 return error("packfile %s signature is unavailable", p->pack_name);
700 idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
701 if (hashcmp(sha1, idx_sha1))
702 return error("packfile %s does not match index", p->pack_name);
703 return 0;
704 }
705
706 static int open_packed_git(struct packed_git *p)
707 {
708 if (!open_packed_git_1(p))
709 return 0;
710 if (p->pack_fd != -1) {
711 close(p->pack_fd);
712 p->pack_fd = -1;
713 }
714 return -1;
715 }
716
717 static int in_window(struct pack_window *win, off_t offset)
718 {
719 /* We must promise at least 20 bytes (one hash) after the
720 * offset is available from this window, otherwise the offset
721 * is not actually in this window and a different window (which
722 * has that one hash excess) must be used. This is to support
723 * the object header and delta base parsing routines below.
724 */
725 off_t win_off = win->offset;
726 return win_off <= offset
727 && (offset + 20) <= (win_off + win->len);
728 }
729
730 unsigned char *use_pack(struct packed_git *p,
731 struct pack_window **w_cursor,
732 off_t offset,
733 unsigned int *left)
734 {
735 struct pack_window *win = *w_cursor;
736
737 if (p->pack_fd == -1 && open_packed_git(p))
738 die("packfile %s cannot be accessed", p->pack_name);
739
740 /* Since packfiles end in a hash of their content and it's
741 * pointless to ask for an offset into the middle of that
742 * hash, and the in_window function above wouldn't match
743 * don't allow an offset too close to the end of the file.
744 */
745 if (offset > (p->pack_size - 20))
746 die("offset beyond end of packfile (truncated pack?)");
747
748 if (!win || !in_window(win, offset)) {
749 if (win)
750 win->inuse_cnt--;
751 for (win = p->windows; win; win = win->next) {
752 if (in_window(win, offset))
753 break;
754 }
755 if (!win) {
756 size_t window_align = packed_git_window_size / 2;
757 off_t len;
758 win = xcalloc(1, sizeof(*win));
759 win->offset = (offset / window_align) * window_align;
760 len = p->pack_size - win->offset;
761 if (len > packed_git_window_size)
762 len = packed_git_window_size;
763 win->len = (size_t)len;
764 pack_mapped += win->len;
765 while (packed_git_limit < pack_mapped
766 && unuse_one_window(p, p->pack_fd))
767 ; /* nothing */
768 win->base = xmmap(NULL, win->len,
769 PROT_READ, MAP_PRIVATE,
770 p->pack_fd, win->offset);
771 if (win->base == MAP_FAILED)
772 die("packfile %s cannot be mapped: %s",
773 p->pack_name,
774 strerror(errno));
775 pack_mmap_calls++;
776 pack_open_windows++;
777 if (pack_mapped > peak_pack_mapped)
778 peak_pack_mapped = pack_mapped;
779 if (pack_open_windows > peak_pack_open_windows)
780 peak_pack_open_windows = pack_open_windows;
781 win->next = p->windows;
782 p->windows = win;
783 }
784 }
785 if (win != *w_cursor) {
786 win->last_used = pack_used_ctr++;
787 win->inuse_cnt++;
788 *w_cursor = win;
789 }
790 offset -= win->offset;
791 if (left)
792 *left = win->len - xsize_t(offset);
793 return win->base + offset;
794 }
795
796 static struct packed_git *alloc_packed_git(int extra)
797 {
798 struct packed_git *p = xmalloc(sizeof(*p) + extra);
799 memset(p, 0, sizeof(*p));
800 p->pack_fd = -1;
801 return p;
802 }
803
804 struct packed_git *add_packed_git(const char *path, int path_len, int local)
805 {
806 struct stat st;
807 struct packed_git *p = alloc_packed_git(path_len + 2);
808
809 /*
810 * Make sure a corresponding .pack file exists and that
811 * the index looks sane.
812 */
813 path_len -= strlen(".idx");
814 if (path_len < 1) {
815 free(p);
816 return NULL;
817 }
818 memcpy(p->pack_name, path, path_len);
819
820 strcpy(p->pack_name + path_len, ".keep");
821 if (!access(p->pack_name, F_OK))
822 p->pack_keep = 1;
823
824 strcpy(p->pack_name + path_len, ".pack");
825 if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
826 free(p);
827 return NULL;
828 }
829
830 /* ok, it looks sane as far as we can check without
831 * actually mapping the pack file.
832 */
833 p->pack_size = st.st_size;
834 p->pack_local = local;
835 p->mtime = st.st_mtime;
836 if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
837 hashclr(p->sha1);
838 return p;
839 }
840
841 struct packed_git *parse_pack_index(unsigned char *sha1)
842 {
843 const char *idx_path = sha1_pack_index_name(sha1);
844 const char *path = sha1_pack_name(sha1);
845 struct packed_git *p = alloc_packed_git(strlen(path) + 1);
846
847 strcpy(p->pack_name, path);
848 hashcpy(p->sha1, sha1);
849 if (check_packed_git_idx(idx_path, p)) {
850 free(p);
851 return NULL;
852 }
853
854 return p;
855 }
856
857 void install_packed_git(struct packed_git *pack)
858 {
859 pack->next = packed_git;
860 packed_git = pack;
861 }
862
863 static void prepare_packed_git_one(char *objdir, int local)
864 {
865 /* Ensure that this buffer is large enough so that we can
866 append "/pack/" without clobbering the stack even if
867 strlen(objdir) were PATH_MAX. */
868 char path[PATH_MAX + 1 + 4 + 1 + 1];
869 int len;
870 DIR *dir;
871 struct dirent *de;
872
873 sprintf(path, "%s/pack", objdir);
874 len = strlen(path);
875 dir = opendir(path);
876 while (!dir && errno == EMFILE && unuse_one_window(packed_git, -1))
877 dir = opendir(path);
878 if (!dir) {
879 if (errno != ENOENT)
880 error("unable to open object pack directory: %s: %s",
881 path, strerror(errno));
882 return;
883 }
884 path[len++] = '/';
885 while ((de = readdir(dir)) != NULL) {
886 int namelen = strlen(de->d_name);
887 struct packed_git *p;
888
889 if (!has_extension(de->d_name, ".idx"))
890 continue;
891
892 if (len + namelen + 1 > sizeof(path))
893 continue;
894
895 /* Don't reopen a pack we already have. */
896 strcpy(path + len, de->d_name);
897 for (p = packed_git; p; p = p->next) {
898 if (!memcmp(path, p->pack_name, len + namelen - 4))
899 break;
900 }
901 if (p)
902 continue;
903 /* See if it really is a valid .idx file with corresponding
904 * .pack file that we can map.
905 */
906 p = add_packed_git(path, len + namelen, local);
907 if (!p)
908 continue;
909 install_packed_git(p);
910 }
911 closedir(dir);
912 }
913
914 static int sort_pack(const void *a_, const void *b_)
915 {
916 struct packed_git *a = *((struct packed_git **)a_);
917 struct packed_git *b = *((struct packed_git **)b_);
918 int st;
919
920 /*
921 * Local packs tend to contain objects specific to our
922 * variant of the project than remote ones. In addition,
923 * remote ones could be on a network mounted filesystem.
924 * Favor local ones for these reasons.
925 */
926 st = a->pack_local - b->pack_local;
927 if (st)
928 return -st;
929
930 /*
931 * Younger packs tend to contain more recent objects,
932 * and more recent objects tend to get accessed more
933 * often.
934 */
935 if (a->mtime < b->mtime)
936 return 1;
937 else if (a->mtime == b->mtime)
938 return 0;
939 return -1;
940 }
941
942 static void rearrange_packed_git(void)
943 {
944 struct packed_git **ary, *p;
945 int i, n;
946
947 for (n = 0, p = packed_git; p; p = p->next)
948 n++;
949 if (n < 2)
950 return;
951
952 /* prepare an array of packed_git for easier sorting */
953 ary = xcalloc(n, sizeof(struct packed_git *));
954 for (n = 0, p = packed_git; p; p = p->next)
955 ary[n++] = p;
956
957 qsort(ary, n, sizeof(struct packed_git *), sort_pack);
958
959 /* link them back again */
960 for (i = 0; i < n - 1; i++)
961 ary[i]->next = ary[i + 1];
962 ary[n - 1]->next = NULL;
963 packed_git = ary[0];
964
965 free(ary);
966 }
967
968 static int prepare_packed_git_run_once = 0;
969 void prepare_packed_git(void)
970 {
971 struct alternate_object_database *alt;
972
973 if (prepare_packed_git_run_once)
974 return;
975 prepare_packed_git_one(get_object_directory(), 1);
976 prepare_alt_odb();
977 for (alt = alt_odb_list; alt; alt = alt->next) {
978 alt->name[-1] = 0;
979 prepare_packed_git_one(alt->base, 0);
980 alt->name[-1] = '/';
981 }
982 rearrange_packed_git();
983 prepare_packed_git_run_once = 1;
984 }
985
986 void reprepare_packed_git(void)
987 {
988 discard_revindex();
989 prepare_packed_git_run_once = 0;
990 prepare_packed_git();
991 }
992
993 static void mark_bad_packed_object(struct packed_git *p,
994 const unsigned char *sha1)
995 {
996 unsigned i;
997 for (i = 0; i < p->num_bad_objects; i++)
998 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
999 return;
1000 p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1));
1001 hashcpy(p->bad_object_sha1 + 20 * p->num_bad_objects, sha1);
1002 p->num_bad_objects++;
1003 }
1004
1005 static int has_packed_and_bad(const unsigned char *sha1)
1006 {
1007 struct packed_git *p;
1008 unsigned i;
1009
1010 for (p = packed_git; p; p = p->next)
1011 for (i = 0; i < p->num_bad_objects; i++)
1012 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1013 return 1;
1014 return 0;
1015 }
1016
1017 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
1018 {
1019 unsigned char real_sha1[20];
1020 hash_sha1_file(map, size, type, real_sha1);
1021 return hashcmp(sha1, real_sha1) ? -1 : 0;
1022 }
1023
1024 static int git_open_noatime(const char *name)
1025 {
1026 static int sha1_file_open_flag = O_NOATIME;
1027 int fd = open(name, O_RDONLY | sha1_file_open_flag);
1028
1029 /* Might the failure be due to O_NOATIME? */
1030 if (fd < 0 && errno != ENOENT && sha1_file_open_flag) {
1031 fd = open(name, O_RDONLY);
1032 if (fd >= 0)
1033 sha1_file_open_flag = 0;
1034 }
1035 return fd;
1036 }
1037
1038 static int open_sha1_file(const unsigned char *sha1)
1039 {
1040 int fd;
1041 char *name = sha1_file_name(sha1);
1042 struct alternate_object_database *alt;
1043
1044 fd = git_open_noatime(name);
1045 if (fd >= 0)
1046 return fd;
1047
1048 prepare_alt_odb();
1049 errno = ENOENT;
1050 for (alt = alt_odb_list; alt; alt = alt->next) {
1051 name = alt->name;
1052 fill_sha1_path(name, sha1);
1053 fd = git_open_noatime(alt->base);
1054 if (fd >= 0)
1055 return fd;
1056 }
1057 return -1;
1058 }
1059
1060 static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1061 {
1062 void *map;
1063 int fd;
1064
1065 fd = open_sha1_file(sha1);
1066 map = NULL;
1067 if (fd >= 0) {
1068 struct stat st;
1069
1070 if (!fstat(fd, &st)) {
1071 *size = xsize_t(st.st_size);
1072 map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1073 }
1074 close(fd);
1075 }
1076 return map;
1077 }
1078
1079 static int legacy_loose_object(unsigned char *map)
1080 {
1081 unsigned int word;
1082
1083 /*
1084 * Is it a zlib-compressed buffer? If so, the first byte
1085 * must be 0x78 (15-bit window size, deflated), and the
1086 * first 16-bit word is evenly divisible by 31
1087 */
1088 word = (map[0] << 8) + map[1];
1089 if (map[0] == 0x78 && !(word % 31))
1090 return 1;
1091 else
1092 return 0;
1093 }
1094
1095 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1096 unsigned long len, enum object_type *type, unsigned long *sizep)
1097 {
1098 unsigned shift;
1099 unsigned long size, c;
1100 unsigned long used = 0;
1101
1102 c = buf[used++];
1103 *type = (c >> 4) & 7;
1104 size = c & 15;
1105 shift = 4;
1106 while (c & 0x80) {
1107 if (len <= used || bitsizeof(long) <= shift) {
1108 error("bad object header");
1109 return 0;
1110 }
1111 c = buf[used++];
1112 size += (c & 0x7f) << shift;
1113 shift += 7;
1114 }
1115 *sizep = size;
1116 return used;
1117 }
1118
1119 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1120 {
1121 unsigned long size, used;
1122 static const char valid_loose_object_type[8] = {
1123 0, /* OBJ_EXT */
1124 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
1125 0, /* "delta" and others are invalid in a loose object */
1126 };
1127 enum object_type type;
1128
1129 /* Get the data stream */
1130 memset(stream, 0, sizeof(*stream));
1131 stream->next_in = map;
1132 stream->avail_in = mapsize;
1133 stream->next_out = buffer;
1134 stream->avail_out = bufsiz;
1135
1136 if (legacy_loose_object(map)) {
1137 git_inflate_init(stream);
1138 return git_inflate(stream, 0);
1139 }
1140
1141
1142 /*
1143 * There used to be a second loose object header format which
1144 * was meant to mimic the in-pack format, allowing for direct
1145 * copy of the object data. This format turned up not to be
1146 * really worth it and we don't write it any longer. But we
1147 * can still read it.
1148 */
1149 used = unpack_object_header_buffer(map, mapsize, &type, &size);
1150 if (!used || !valid_loose_object_type[type])
1151 return -1;
1152 map += used;
1153 mapsize -= used;
1154
1155 /* Set up the stream for the rest.. */
1156 stream->next_in = map;
1157 stream->avail_in = mapsize;
1158 git_inflate_init(stream);
1159
1160 /* And generate the fake traditional header */
1161 stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
1162 typename(type), size);
1163 return 0;
1164 }
1165
1166 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1167 {
1168 int bytes = strlen(buffer) + 1;
1169 unsigned char *buf = xmallocz(size);
1170 unsigned long n;
1171 int status = Z_OK;
1172
1173 n = stream->total_out - bytes;
1174 if (n > size)
1175 n = size;
1176 memcpy(buf, (char *) buffer + bytes, n);
1177 bytes = n;
1178 if (bytes <= size) {
1179 /*
1180 * The above condition must be (bytes <= size), not
1181 * (bytes < size). In other words, even though we
1182 * expect no more output and set avail_out to zer0,
1183 * the input zlib stream may have bytes that express
1184 * "this concludes the stream", and we *do* want to
1185 * eat that input.
1186 *
1187 * Otherwise we would not be able to test that we
1188 * consumed all the input to reach the expected size;
1189 * we also want to check that zlib tells us that all
1190 * went well with status == Z_STREAM_END at the end.
1191 */
1192 stream->next_out = buf + bytes;
1193 stream->avail_out = size - bytes;
1194 while (status == Z_OK)
1195 status = git_inflate(stream, Z_FINISH);
1196 }
1197 if (status == Z_STREAM_END && !stream->avail_in) {
1198 git_inflate_end(stream);
1199 return buf;
1200 }
1201
1202 if (status < 0)
1203 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1204 else if (stream->avail_in)
1205 error("garbage at end of loose object '%s'",
1206 sha1_to_hex(sha1));
1207 free(buf);
1208 return NULL;
1209 }
1210
1211 /*
1212 * We used to just use "sscanf()", but that's actually way
1213 * too permissive for what we want to check. So do an anal
1214 * object header parse by hand.
1215 */
1216 static int parse_sha1_header(const char *hdr, unsigned long *sizep)
1217 {
1218 char type[10];
1219 int i;
1220 unsigned long size;
1221
1222 /*
1223 * The type can be at most ten bytes (including the
1224 * terminating '\0' that we add), and is followed by
1225 * a space.
1226 */
1227 i = 0;
1228 for (;;) {
1229 char c = *hdr++;
1230 if (c == ' ')
1231 break;
1232 type[i++] = c;
1233 if (i >= sizeof(type))
1234 return -1;
1235 }
1236 type[i] = 0;
1237
1238 /*
1239 * The length must follow immediately, and be in canonical
1240 * decimal format (ie "010" is not valid).
1241 */
1242 size = *hdr++ - '0';
1243 if (size > 9)
1244 return -1;
1245 if (size) {
1246 for (;;) {
1247 unsigned long c = *hdr - '0';
1248 if (c > 9)
1249 break;
1250 hdr++;
1251 size = size * 10 + c;
1252 }
1253 }
1254 *sizep = size;
1255
1256 /*
1257 * The length must be followed by a zero byte
1258 */
1259 return *hdr ? -1 : type_from_string(type);
1260 }
1261
1262 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1263 {
1264 int ret;
1265 z_stream stream;
1266 char hdr[8192];
1267
1268 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1269 if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1270 return NULL;
1271
1272 return unpack_sha1_rest(&stream, hdr, *size, sha1);
1273 }
1274
1275 unsigned long get_size_from_delta(struct packed_git *p,
1276 struct pack_window **w_curs,
1277 off_t curpos)
1278 {
1279 const unsigned char *data;
1280 unsigned char delta_head[20], *in;
1281 z_stream stream;
1282 int st;
1283
1284 memset(&stream, 0, sizeof(stream));
1285 stream.next_out = delta_head;
1286 stream.avail_out = sizeof(delta_head);
1287
1288 git_inflate_init(&stream);
1289 do {
1290 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1291 stream.next_in = in;
1292 st = git_inflate(&stream, Z_FINISH);
1293 curpos += stream.next_in - in;
1294 } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1295 stream.total_out < sizeof(delta_head));
1296 git_inflate_end(&stream);
1297 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1298 error("delta data unpack-initial failed");
1299 return 0;
1300 }
1301
1302 /* Examine the initial part of the delta to figure out
1303 * the result size.
1304 */
1305 data = delta_head;
1306
1307 /* ignore base size */
1308 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1309
1310 /* Read the result size */
1311 return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1312 }
1313
1314 static off_t get_delta_base(struct packed_git *p,
1315 struct pack_window **w_curs,
1316 off_t *curpos,
1317 enum object_type type,
1318 off_t delta_obj_offset)
1319 {
1320 unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1321 off_t base_offset;
1322
1323 /* use_pack() assured us we have [base_info, base_info + 20)
1324 * as a range that we can look at without walking off the
1325 * end of the mapped window. Its actually the hash size
1326 * that is assured. An OFS_DELTA longer than the hash size
1327 * is stupid, as then a REF_DELTA would be smaller to store.
1328 */
1329 if (type == OBJ_OFS_DELTA) {
1330 unsigned used = 0;
1331 unsigned char c = base_info[used++];
1332 base_offset = c & 127;
1333 while (c & 128) {
1334 base_offset += 1;
1335 if (!base_offset || MSB(base_offset, 7))
1336 return 0; /* overflow */
1337 c = base_info[used++];
1338 base_offset = (base_offset << 7) + (c & 127);
1339 }
1340 base_offset = delta_obj_offset - base_offset;
1341 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1342 return 0; /* out of bound */
1343 *curpos += used;
1344 } else if (type == OBJ_REF_DELTA) {
1345 /* The base entry _must_ be in the same pack */
1346 base_offset = find_pack_entry_one(base_info, p);
1347 *curpos += 20;
1348 } else
1349 die("I am totally screwed");
1350 return base_offset;
1351 }
1352
1353 /* forward declaration for a mutually recursive function */
1354 static int packed_object_info(struct packed_git *p, off_t offset,
1355 unsigned long *sizep);
1356
1357 static int packed_delta_info(struct packed_git *p,
1358 struct pack_window **w_curs,
1359 off_t curpos,
1360 enum object_type type,
1361 off_t obj_offset,
1362 unsigned long *sizep)
1363 {
1364 off_t base_offset;
1365
1366 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1367 if (!base_offset)
1368 return OBJ_BAD;
1369 type = packed_object_info(p, base_offset, NULL);
1370 if (type <= OBJ_NONE) {
1371 struct revindex_entry *revidx;
1372 const unsigned char *base_sha1;
1373 revidx = find_pack_revindex(p, base_offset);
1374 if (!revidx)
1375 return OBJ_BAD;
1376 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1377 mark_bad_packed_object(p, base_sha1);
1378 type = sha1_object_info(base_sha1, NULL);
1379 if (type <= OBJ_NONE)
1380 return OBJ_BAD;
1381 }
1382
1383 /* We choose to only get the type of the base object and
1384 * ignore potentially corrupt pack file that expects the delta
1385 * based on a base with a wrong size. This saves tons of
1386 * inflate() calls.
1387 */
1388 if (sizep) {
1389 *sizep = get_size_from_delta(p, w_curs, curpos);
1390 if (*sizep == 0)
1391 type = OBJ_BAD;
1392 }
1393
1394 return type;
1395 }
1396
1397 static int unpack_object_header(struct packed_git *p,
1398 struct pack_window **w_curs,
1399 off_t *curpos,
1400 unsigned long *sizep)
1401 {
1402 unsigned char *base;
1403 unsigned int left;
1404 unsigned long used;
1405 enum object_type type;
1406
1407 /* use_pack() assures us we have [base, base + 20) available
1408 * as a range that we can look at at. (Its actually the hash
1409 * size that is assured.) With our object header encoding
1410 * the maximum deflated object size is 2^137, which is just
1411 * insane, so we know won't exceed what we have been given.
1412 */
1413 base = use_pack(p, w_curs, *curpos, &left);
1414 used = unpack_object_header_buffer(base, left, &type, sizep);
1415 if (!used) {
1416 type = OBJ_BAD;
1417 } else
1418 *curpos += used;
1419
1420 return type;
1421 }
1422
1423 const char *packed_object_info_detail(struct packed_git *p,
1424 off_t obj_offset,
1425 unsigned long *size,
1426 unsigned long *store_size,
1427 unsigned int *delta_chain_length,
1428 unsigned char *base_sha1)
1429 {
1430 struct pack_window *w_curs = NULL;
1431 off_t curpos;
1432 unsigned long dummy;
1433 unsigned char *next_sha1;
1434 enum object_type type;
1435 struct revindex_entry *revidx;
1436
1437 *delta_chain_length = 0;
1438 curpos = obj_offset;
1439 type = unpack_object_header(p, &w_curs, &curpos, size);
1440
1441 revidx = find_pack_revindex(p, obj_offset);
1442 *store_size = revidx[1].offset - obj_offset;
1443
1444 for (;;) {
1445 switch (type) {
1446 default:
1447 die("pack %s contains unknown object type %d",
1448 p->pack_name, type);
1449 case OBJ_COMMIT:
1450 case OBJ_TREE:
1451 case OBJ_BLOB:
1452 case OBJ_TAG:
1453 unuse_pack(&w_curs);
1454 return typename(type);
1455 case OBJ_OFS_DELTA:
1456 obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1457 if (!obj_offset)
1458 die("pack %s contains bad delta base reference of type %s",
1459 p->pack_name, typename(type));
1460 if (*delta_chain_length == 0) {
1461 revidx = find_pack_revindex(p, obj_offset);
1462 hashcpy(base_sha1, nth_packed_object_sha1(p, revidx->nr));
1463 }
1464 break;
1465 case OBJ_REF_DELTA:
1466 next_sha1 = use_pack(p, &w_curs, curpos, NULL);
1467 if (*delta_chain_length == 0)
1468 hashcpy(base_sha1, next_sha1);
1469 obj_offset = find_pack_entry_one(next_sha1, p);
1470 break;
1471 }
1472 (*delta_chain_length)++;
1473 curpos = obj_offset;
1474 type = unpack_object_header(p, &w_curs, &curpos, &dummy);
1475 }
1476 }
1477
1478 static int packed_object_info(struct packed_git *p, off_t obj_offset,
1479 unsigned long *sizep)
1480 {
1481 struct pack_window *w_curs = NULL;
1482 unsigned long size;
1483 off_t curpos = obj_offset;
1484 enum object_type type;
1485
1486 type = unpack_object_header(p, &w_curs, &curpos, &size);
1487
1488 switch (type) {
1489 case OBJ_OFS_DELTA:
1490 case OBJ_REF_DELTA:
1491 type = packed_delta_info(p, &w_curs, curpos,
1492 type, obj_offset, sizep);
1493 break;
1494 case OBJ_COMMIT:
1495 case OBJ_TREE:
1496 case OBJ_BLOB:
1497 case OBJ_TAG:
1498 if (sizep)
1499 *sizep = size;
1500 break;
1501 default:
1502 error("unknown object type %i at offset %"PRIuMAX" in %s",
1503 type, (uintmax_t)obj_offset, p->pack_name);
1504 type = OBJ_BAD;
1505 }
1506 unuse_pack(&w_curs);
1507 return type;
1508 }
1509
1510 static void *unpack_compressed_entry(struct packed_git *p,
1511 struct pack_window **w_curs,
1512 off_t curpos,
1513 unsigned long size)
1514 {
1515 int st;
1516 z_stream stream;
1517 unsigned char *buffer, *in;
1518
1519 buffer = xmallocz(size);
1520 memset(&stream, 0, sizeof(stream));
1521 stream.next_out = buffer;
1522 stream.avail_out = size + 1;
1523
1524 git_inflate_init(&stream);
1525 do {
1526 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1527 stream.next_in = in;
1528 st = git_inflate(&stream, Z_FINISH);
1529 if (!stream.avail_out)
1530 break; /* the payload is larger than it should be */
1531 curpos += stream.next_in - in;
1532 } while (st == Z_OK || st == Z_BUF_ERROR);
1533 git_inflate_end(&stream);
1534 if ((st != Z_STREAM_END) || stream.total_out != size) {
1535 free(buffer);
1536 return NULL;
1537 }
1538
1539 return buffer;
1540 }
1541
1542 #define MAX_DELTA_CACHE (256)
1543
1544 static size_t delta_base_cached;
1545
1546 static struct delta_base_cache_lru_list {
1547 struct delta_base_cache_lru_list *prev;
1548 struct delta_base_cache_lru_list *next;
1549 } delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
1550
1551 static struct delta_base_cache_entry {
1552 struct delta_base_cache_lru_list lru;
1553 void *data;
1554 struct packed_git *p;
1555 off_t base_offset;
1556 unsigned long size;
1557 enum object_type type;
1558 } delta_base_cache[MAX_DELTA_CACHE];
1559
1560 static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
1561 {
1562 unsigned long hash;
1563
1564 hash = (unsigned long)p + (unsigned long)base_offset;
1565 hash += (hash >> 8) + (hash >> 16);
1566 return hash % MAX_DELTA_CACHE;
1567 }
1568
1569 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1570 unsigned long *base_size, enum object_type *type, int keep_cache)
1571 {
1572 void *ret;
1573 unsigned long hash = pack_entry_hash(p, base_offset);
1574 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1575
1576 ret = ent->data;
1577 if (!ret || ent->p != p || ent->base_offset != base_offset)
1578 return unpack_entry(p, base_offset, type, base_size);
1579
1580 if (!keep_cache) {
1581 ent->data = NULL;
1582 ent->lru.next->prev = ent->lru.prev;
1583 ent->lru.prev->next = ent->lru.next;
1584 delta_base_cached -= ent->size;
1585 } else {
1586 ret = xmemdupz(ent->data, ent->size);
1587 }
1588 *type = ent->type;
1589 *base_size = ent->size;
1590 return ret;
1591 }
1592
1593 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1594 {
1595 if (ent->data) {
1596 free(ent->data);
1597 ent->data = NULL;
1598 ent->lru.next->prev = ent->lru.prev;
1599 ent->lru.prev->next = ent->lru.next;
1600 delta_base_cached -= ent->size;
1601 }
1602 }
1603
1604 void clear_delta_base_cache(void)
1605 {
1606 unsigned long p;
1607 for (p = 0; p < MAX_DELTA_CACHE; p++)
1608 release_delta_base_cache(&delta_base_cache[p]);
1609 }
1610
1611 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1612 void *base, unsigned long base_size, enum object_type type)
1613 {
1614 unsigned long hash = pack_entry_hash(p, base_offset);
1615 struct delta_base_cache_entry *ent = delta_base_cache + hash;
1616 struct delta_base_cache_lru_list *lru;
1617
1618 release_delta_base_cache(ent);
1619 delta_base_cached += base_size;
1620
1621 for (lru = delta_base_cache_lru.next;
1622 delta_base_cached > delta_base_cache_limit
1623 && lru != &delta_base_cache_lru;
1624 lru = lru->next) {
1625 struct delta_base_cache_entry *f = (void *)lru;
1626 if (f->type == OBJ_BLOB)
1627 release_delta_base_cache(f);
1628 }
1629 for (lru = delta_base_cache_lru.next;
1630 delta_base_cached > delta_base_cache_limit
1631 && lru != &delta_base_cache_lru;
1632 lru = lru->next) {
1633 struct delta_base_cache_entry *f = (void *)lru;
1634 release_delta_base_cache(f);
1635 }
1636
1637 ent->p = p;
1638 ent->base_offset = base_offset;
1639 ent->type = type;
1640 ent->data = base;
1641 ent->size = base_size;
1642 ent->lru.next = &delta_base_cache_lru;
1643 ent->lru.prev = delta_base_cache_lru.prev;
1644 delta_base_cache_lru.prev->next = &ent->lru;
1645 delta_base_cache_lru.prev = &ent->lru;
1646 }
1647
1648 static void *read_object(const unsigned char *sha1, enum object_type *type,
1649 unsigned long *size);
1650
1651 static void *unpack_delta_entry(struct packed_git *p,
1652 struct pack_window **w_curs,
1653 off_t curpos,
1654 unsigned long delta_size,
1655 off_t obj_offset,
1656 enum object_type *type,
1657 unsigned long *sizep)
1658 {
1659 void *delta_data, *result, *base;
1660 unsigned long base_size;
1661 off_t base_offset;
1662
1663 base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
1664 if (!base_offset) {
1665 error("failed to validate delta base reference "
1666 "at offset %"PRIuMAX" from %s",
1667 (uintmax_t)curpos, p->pack_name);
1668 return NULL;
1669 }
1670 unuse_pack(w_curs);
1671 base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
1672 if (!base) {
1673 /*
1674 * We're probably in deep shit, but let's try to fetch
1675 * the required base anyway from another pack or loose.
1676 * This is costly but should happen only in the presence
1677 * of a corrupted pack, and is better than failing outright.
1678 */
1679 struct revindex_entry *revidx;
1680 const unsigned char *base_sha1;
1681 revidx = find_pack_revindex(p, base_offset);
1682 if (!revidx)
1683 return NULL;
1684 base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1685 error("failed to read delta base object %s"
1686 " at offset %"PRIuMAX" from %s",
1687 sha1_to_hex(base_sha1), (uintmax_t)base_offset,
1688 p->pack_name);
1689 mark_bad_packed_object(p, base_sha1);
1690 base = read_object(base_sha1, type, &base_size);
1691 if (!base)
1692 return NULL;
1693 }
1694
1695 delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
1696 if (!delta_data) {
1697 error("failed to unpack compressed delta "
1698 "at offset %"PRIuMAX" from %s",
1699 (uintmax_t)curpos, p->pack_name);
1700 free(base);
1701 return NULL;
1702 }
1703 result = patch_delta(base, base_size,
1704 delta_data, delta_size,
1705 sizep);
1706 if (!result)
1707 die("failed to apply delta");
1708 free(delta_data);
1709 add_delta_base_cache(p, base_offset, base, base_size, *type);
1710 return result;
1711 }
1712
1713 int do_check_packed_object_crc;
1714
1715 void *unpack_entry(struct packed_git *p, off_t obj_offset,
1716 enum object_type *type, unsigned long *sizep)
1717 {
1718 struct pack_window *w_curs = NULL;
1719 off_t curpos = obj_offset;
1720 void *data;
1721
1722 if (do_check_packed_object_crc && p->index_version > 1) {
1723 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1724 unsigned long len = revidx[1].offset - obj_offset;
1725 if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1726 const unsigned char *sha1 =
1727 nth_packed_object_sha1(p, revidx->nr);
1728 error("bad packed object CRC for %s",
1729 sha1_to_hex(sha1));
1730 mark_bad_packed_object(p, sha1);
1731 unuse_pack(&w_curs);
1732 return NULL;
1733 }
1734 }
1735
1736 *type = unpack_object_header(p, &w_curs, &curpos, sizep);
1737 switch (*type) {
1738 case OBJ_OFS_DELTA:
1739 case OBJ_REF_DELTA:
1740 data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
1741 obj_offset, type, sizep);
1742 break;
1743 case OBJ_COMMIT:
1744 case OBJ_TREE:
1745 case OBJ_BLOB:
1746 case OBJ_TAG:
1747 data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
1748 break;
1749 default:
1750 data = NULL;
1751 error("unknown object type %i at offset %"PRIuMAX" in %s",
1752 *type, (uintmax_t)obj_offset, p->pack_name);
1753 }
1754 unuse_pack(&w_curs);
1755 return data;
1756 }
1757
1758 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1759 uint32_t n)
1760 {
1761 const unsigned char *index = p->index_data;
1762 if (!index) {
1763 if (open_pack_index(p))
1764 return NULL;
1765 index = p->index_data;
1766 }
1767 if (n >= p->num_objects)
1768 return NULL;
1769 index += 4 * 256;
1770 if (p->index_version == 1) {
1771 return index + 24 * n + 4;
1772 } else {
1773 index += 8;
1774 return index + 20 * n;
1775 }
1776 }
1777
1778 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1779 {
1780 const unsigned char *index = p->index_data;
1781 index += 4 * 256;
1782 if (p->index_version == 1) {
1783 return ntohl(*((uint32_t *)(index + 24 * n)));
1784 } else {
1785 uint32_t off;
1786 index += 8 + p->num_objects * (20 + 4);
1787 off = ntohl(*((uint32_t *)(index + 4 * n)));
1788 if (!(off & 0x80000000))
1789 return off;
1790 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1791 return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
1792 ntohl(*((uint32_t *)(index + 4)));
1793 }
1794 }
1795
1796 off_t find_pack_entry_one(const unsigned char *sha1,
1797 struct packed_git *p)
1798 {
1799 const uint32_t *level1_ofs = p->index_data;
1800 const unsigned char *index = p->index_data;
1801 unsigned hi, lo, stride;
1802 static int use_lookup = -1;
1803 static int debug_lookup = -1;
1804
1805 if (debug_lookup < 0)
1806 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
1807
1808 if (!index) {
1809 if (open_pack_index(p))
1810 return 0;
1811 level1_ofs = p->index_data;
1812 index = p->index_data;
1813 }
1814 if (p->index_version > 1) {
1815 level1_ofs += 2;
1816 index += 8;
1817 }
1818 index += 4 * 256;
1819 hi = ntohl(level1_ofs[*sha1]);
1820 lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1821 if (p->index_version > 1) {
1822 stride = 20;
1823 } else {
1824 stride = 24;
1825 index += 4;
1826 }
1827
1828 if (debug_lookup)
1829 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
1830 sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
1831
1832 if (use_lookup < 0)
1833 use_lookup = !!getenv("GIT_USE_LOOKUP");
1834 if (use_lookup) {
1835 int pos = sha1_entry_pos(index, stride, 0,
1836 lo, hi, p->num_objects, sha1);
1837 if (pos < 0)
1838 return 0;
1839 return nth_packed_object_offset(p, pos);
1840 }
1841
1842 do {
1843 unsigned mi = (lo + hi) / 2;
1844 int cmp = hashcmp(index + mi * stride, sha1);
1845
1846 if (debug_lookup)
1847 printf("lo %u hi %u rg %u mi %u\n",
1848 lo, hi, hi - lo, mi);
1849 if (!cmp)
1850 return nth_packed_object_offset(p, mi);
1851 if (cmp > 0)
1852 hi = mi;
1853 else
1854 lo = mi+1;
1855 } while (lo < hi);
1856 return 0;
1857 }
1858
1859 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1860 {
1861 static struct packed_git *last_found = (void *)1;
1862 struct packed_git *p;
1863 off_t offset;
1864
1865 prepare_packed_git();
1866 if (!packed_git)
1867 return 0;
1868 p = (last_found == (void *)1) ? packed_git : last_found;
1869
1870 do {
1871 if (p->num_bad_objects) {
1872 unsigned i;
1873 for (i = 0; i < p->num_bad_objects; i++)
1874 if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1875 goto next;
1876 }
1877
1878 offset = find_pack_entry_one(sha1, p);
1879 if (offset) {
1880 /*
1881 * We are about to tell the caller where they can
1882 * locate the requested object. We better make
1883 * sure the packfile is still here and can be
1884 * accessed before supplying that answer, as
1885 * it may have been deleted since the index
1886 * was loaded!
1887 */
1888 if (p->pack_fd == -1 && open_packed_git(p)) {
1889 error("packfile %s cannot be accessed", p->pack_name);
1890 goto next;
1891 }
1892 e->offset = offset;
1893 e->p = p;
1894 hashcpy(e->sha1, sha1);
1895 last_found = p;
1896 return 1;
1897 }
1898
1899 next:
1900 if (p == last_found)
1901 p = packed_git;
1902 else
1903 p = p->next;
1904 if (p == last_found)
1905 p = p->next;
1906 } while (p);
1907 return 0;
1908 }
1909
1910 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1911 struct packed_git *packs)
1912 {
1913 struct packed_git *p;
1914
1915 for (p = packs; p; p = p->next) {
1916 if (find_pack_entry_one(sha1, p))
1917 return p;
1918 }
1919 return NULL;
1920
1921 }
1922
1923 static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
1924 {
1925 int status;
1926 unsigned long mapsize, size;
1927 void *map;
1928 z_stream stream;
1929 char hdr[32];
1930
1931 map = map_sha1_file(sha1, &mapsize);
1932 if (!map)
1933 return error("unable to find %s", sha1_to_hex(sha1));
1934 if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1935 status = error("unable to unpack %s header",
1936 sha1_to_hex(sha1));
1937 else if ((status = parse_sha1_header(hdr, &size)) < 0)
1938 status = error("unable to parse %s header", sha1_to_hex(sha1));
1939 else if (sizep)
1940 *sizep = size;
1941 git_inflate_end(&stream);
1942 munmap(map, mapsize);
1943 return status;
1944 }
1945
1946 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1947 {
1948 struct pack_entry e;
1949 int status;
1950
1951 if (!find_pack_entry(sha1, &e)) {
1952 /* Most likely it's a loose object. */
1953 status = sha1_loose_object_info(sha1, sizep);
1954 if (status >= 0)
1955 return status;
1956
1957 /* Not a loose object; someone else may have just packed it. */
1958 reprepare_packed_git();
1959 if (!find_pack_entry(sha1, &e))
1960 return status;
1961 }
1962
1963 status = packed_object_info(e.p, e.offset, sizep);
1964 if (status < 0) {
1965 mark_bad_packed_object(e.p, sha1);
1966 status = sha1_object_info(sha1, sizep);
1967 }
1968
1969 return status;
1970 }
1971
1972 static void *read_packed_sha1(const unsigned char *sha1,
1973 enum object_type *type, unsigned long *size)
1974 {
1975 struct pack_entry e;
1976 void *data;
1977
1978 if (!find_pack_entry(sha1, &e))
1979 return NULL;
1980 data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
1981 if (!data) {
1982 /*
1983 * We're probably in deep shit, but let's try to fetch
1984 * the required object anyway from another pack or loose.
1985 * This should happen only in the presence of a corrupted
1986 * pack, and is better than failing outright.
1987 */
1988 error("failed to read object %s at offset %"PRIuMAX" from %s",
1989 sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
1990 mark_bad_packed_object(e.p, sha1);
1991 data = read_object(sha1, type, size);
1992 }
1993 return data;
1994 }
1995
1996 /*
1997 * This is meant to hold a *small* number of objects that you would
1998 * want read_sha1_file() to be able to return, but yet you do not want
1999 * to write them into the object store (e.g. a browse-only
2000 * application).
2001 */
2002 static struct cached_object {
2003 unsigned char sha1[20];
2004 enum object_type type;
2005 void *buf;
2006 unsigned long size;
2007 } *cached_objects;
2008 static int cached_object_nr, cached_object_alloc;
2009
2010 static struct cached_object empty_tree = {
2011 EMPTY_TREE_SHA1_BIN,
2012 OBJ_TREE,
2013 "",
2014 0
2015 };
2016
2017 static struct cached_object *find_cached_object(const unsigned char *sha1)
2018 {
2019 int i;
2020 struct cached_object *co = cached_objects;
2021
2022 for (i = 0; i < cached_object_nr; i++, co++) {
2023 if (!hashcmp(co->sha1, sha1))
2024 return co;
2025 }
2026 if (!hashcmp(sha1, empty_tree.sha1))
2027 return &empty_tree;
2028 return NULL;
2029 }
2030
2031 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2032 unsigned char *sha1)
2033 {
2034 struct cached_object *co;
2035
2036 hash_sha1_file(buf, len, typename(type), sha1);
2037 if (has_sha1_file(sha1) || find_cached_object(sha1))
2038 return 0;
2039 if (cached_object_alloc <= cached_object_nr) {
2040 cached_object_alloc = alloc_nr(cached_object_alloc);
2041 cached_objects = xrealloc(cached_objects,
2042 sizeof(*cached_objects) *
2043 cached_object_alloc);
2044 }
2045 co = &cached_objects[cached_object_nr++];
2046 co->size = len;
2047 co->type = type;
2048 co->buf = xmalloc(len);
2049 memcpy(co->buf, buf, len);
2050 hashcpy(co->sha1, sha1);
2051 return 0;
2052 }
2053
2054 static void *read_object(const unsigned char *sha1, enum object_type *type,
2055 unsigned long *size)
2056 {
2057 unsigned long mapsize;
2058 void *map, *buf;
2059 struct cached_object *co;
2060
2061 co = find_cached_object(sha1);
2062 if (co) {
2063 *type = co->type;
2064 *size = co->size;
2065 return xmemdupz(co->buf, co->size);
2066 }
2067
2068 buf = read_packed_sha1(sha1, type, size);
2069 if (buf)
2070 return buf;
2071 map = map_sha1_file(sha1, &mapsize);
2072 if (map) {
2073 buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2074 munmap(map, mapsize);
2075 return buf;
2076 }
2077 reprepare_packed_git();
2078 return read_packed_sha1(sha1, type, size);
2079 }
2080
2081 void *read_sha1_file_repl(const unsigned char *sha1,
2082 enum object_type *type,
2083 unsigned long *size,
2084 const unsigned char **replacement)
2085 {
2086 const unsigned char *repl = lookup_replace_object(sha1);
2087 void *data = read_object(repl, type, size);
2088
2089 /* die if we replaced an object with one that does not exist */
2090 if (!data && repl != sha1)
2091 die("replacement %s not found for %s",
2092 sha1_to_hex(repl), sha1_to_hex(sha1));
2093
2094 /* legacy behavior is to die on corrupted objects */
2095 if (!data && (has_loose_object(repl) || has_packed_and_bad(repl)))
2096 die("object %s is corrupted", sha1_to_hex(repl));
2097
2098 if (replacement)
2099 *replacement = repl;
2100
2101 return data;
2102 }
2103
2104 void *read_object_with_reference(const unsigned char *sha1,
2105 const char *required_type_name,
2106 unsigned long *size,
2107 unsigned char *actual_sha1_return)
2108 {
2109 enum object_type type, required_type;
2110 void *buffer;
2111 unsigned long isize;
2112 unsigned char actual_sha1[20];
2113
2114 required_type = type_from_string(required_type_name);
2115 hashcpy(actual_sha1, sha1);
2116 while (1) {
2117 int ref_length = -1;
2118 const char *ref_type = NULL;
2119
2120 buffer = read_sha1_file(actual_sha1, &type, &isize);
2121 if (!buffer)
2122 return NULL;
2123 if (type == required_type) {
2124 *size = isize;
2125 if (actual_sha1_return)
2126 hashcpy(actual_sha1_return, actual_sha1);
2127 return buffer;
2128 }
2129 /* Handle references */
2130 else if (type == OBJ_COMMIT)
2131 ref_type = "tree ";
2132 else if (type == OBJ_TAG)
2133 ref_type = "object ";
2134 else {
2135 free(buffer);
2136 return NULL;
2137 }
2138 ref_length = strlen(ref_type);
2139
2140 if (ref_length + 40 > isize ||
2141 memcmp(buffer, ref_type, ref_length) ||
2142 get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2143 free(buffer);
2144 return NULL;
2145 }
2146 free(buffer);
2147 /* Now we have the ID of the referred-to object in
2148 * actual_sha1. Check again. */
2149 }
2150 }
2151
2152 static void write_sha1_file_prepare(const void *buf, unsigned long len,
2153 const char *type, unsigned char *sha1,
2154 char *hdr, int *hdrlen)
2155 {
2156 git_SHA_CTX c;
2157
2158 /* Generate the header */
2159 *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
2160
2161 /* Sha1.. */
2162 git_SHA1_Init(&c);
2163 git_SHA1_Update(&c, hdr, *hdrlen);
2164 git_SHA1_Update(&c, buf, len);
2165 git_SHA1_Final(sha1, &c);
2166 }
2167
2168 /*
2169 * Move the just written object into its final resting place.
2170 * NEEDSWORK: this should be renamed to finalize_temp_file() as
2171 * "moving" is only a part of what it does, when no patch between
2172 * master to pu changes the call sites of this function.
2173 */
2174 int move_temp_to_file(const char *tmpfile, const char *filename)
2175 {
2176 int ret = 0;
2177
2178 if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2179 goto try_rename;
2180 else if (link(tmpfile, filename))
2181 ret = errno;
2182
2183 /*
2184 * Coda hack - coda doesn't like cross-directory links,
2185 * so we fall back to a rename, which will mean that it
2186 * won't be able to check collisions, but that's not a
2187 * big deal.
2188 *
2189 * The same holds for FAT formatted media.
2190 *
2191 * When this succeeds, we just return. We have nothing
2192 * left to unlink.
2193 */
2194 if (ret && ret != EEXIST) {
2195 try_rename:
2196 if (!rename(tmpfile, filename))
2197 goto out;
2198 ret = errno;
2199 }
2200 unlink_or_warn(tmpfile);
2201 if (ret) {
2202 if (ret != EEXIST) {
2203 return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
2204 }
2205 /* FIXME!!! Collision check here ? */
2206 }
2207
2208 out:
2209 if (set_shared_perm(filename, (S_IFREG|0444)))
2210 return error("unable to set permission to '%s'", filename);
2211 return 0;
2212 }
2213
2214 static int write_buffer(int fd, const void *buf, size_t len)
2215 {
2216 if (write_in_full(fd, buf, len) < 0)
2217 return error("file write error (%s)", strerror(errno));
2218 return 0;
2219 }
2220
2221 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2222 unsigned char *sha1)
2223 {
2224 char hdr[32];
2225 int hdrlen;
2226 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2227 return 0;
2228 }
2229
2230 /* Finalize a file on disk, and close it. */
2231 static void close_sha1_file(int fd)
2232 {
2233 if (fsync_object_files)
2234 fsync_or_die(fd, "sha1 file");
2235 if (close(fd) != 0)
2236 die_errno("error when closing sha1 file");
2237 }
2238
2239 /* Size of directory component, including the ending '/' */
2240 static inline int directory_size(const char *filename)
2241 {
2242 const char *s = strrchr(filename, '/');
2243 if (!s)
2244 return 0;
2245 return s - filename + 1;
2246 }
2247
2248 /*
2249 * This creates a temporary file in the same directory as the final
2250 * 'filename'
2251 *
2252 * We want to avoid cross-directory filename renames, because those
2253 * can have problems on various filesystems (FAT, NFS, Coda).
2254 */
2255 static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
2256 {
2257 int fd, dirlen = directory_size(filename);
2258
2259 if (dirlen + 20 > bufsiz) {
2260 errno = ENAMETOOLONG;
2261 return -1;
2262 }
2263 memcpy(buffer, filename, dirlen);
2264 strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
2265 fd = mkstemp(buffer);
2266 if (fd < 0 && dirlen && errno == ENOENT) {
2267 /* Make sure the directory exists */
2268 memcpy(buffer, filename, dirlen);
2269 buffer[dirlen-1] = 0;
2270 if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
2271 return -1;
2272
2273 /* Try again */
2274 strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
2275 fd = mkstemp(buffer);
2276 }
2277 return fd;
2278 }
2279
2280 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
2281 void *buf, unsigned long len, time_t mtime)
2282 {
2283 int fd, ret;
2284 size_t size;
2285 unsigned char *compressed;
2286 z_stream stream;
2287 char *filename;
2288 static char tmpfile[PATH_MAX];
2289
2290 filename = sha1_file_name(sha1);
2291 fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
2292 while (fd < 0 && errno == EMFILE && unuse_one_window(packed_git, -1))
2293 fd = create_tmpfile(tmpfile, sizeof(tmpfile), filename);
2294 if (fd < 0) {
2295 if (errno == EACCES)
2296 return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
2297 else
2298 return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
2299 }
2300
2301 /* Set it up */
2302 memset(&stream, 0, sizeof(stream));
2303 deflateInit(&stream, zlib_compression_level);
2304 size = 8 + deflateBound(&stream, len+hdrlen);
2305 compressed = xmalloc(size);
2306
2307 /* Compress it */
2308 stream.next_out = compressed;
2309 stream.avail_out = size;
2310
2311 /* First header.. */
2312 stream.next_in = (unsigned char *)hdr;
2313 stream.avail_in = hdrlen;
2314 while (deflate(&stream, 0) == Z_OK)
2315 /* nothing */;
2316
2317 /* Then the data itself.. */
2318 stream.next_in = buf;
2319 stream.avail_in = len;
2320 ret = deflate(&stream, Z_FINISH);
2321 if (ret != Z_STREAM_END)
2322 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
2323
2324 ret = deflateEnd(&stream);
2325 if (ret != Z_OK)
2326 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
2327
2328 size = stream.total_out;
2329
2330 if (write_buffer(fd, compressed, size) < 0)
2331 die("unable to write sha1 file");
2332 close_sha1_file(fd);
2333 free(compressed);
2334
2335 if (mtime) {
2336 struct utimbuf utb;
2337 utb.actime = mtime;
2338 utb.modtime = mtime;
2339 if (utime(tmpfile, &utb) < 0)
2340 warning("failed utime() on %s: %s",
2341 tmpfile, strerror(errno));
2342 }
2343
2344 return move_temp_to_file(tmpfile, filename);
2345 }
2346
2347 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
2348 {
2349 unsigned char sha1[20];
2350 char hdr[32];
2351 int hdrlen;
2352
2353 /* Normally if we have it in the pack then we do not bother writing
2354 * it out into .git/objects/??/?{38} file.
2355 */
2356 write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2357 if (returnsha1)
2358 hashcpy(returnsha1, sha1);
2359 if (has_sha1_file(sha1))
2360 return 0;
2361 return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
2362 }
2363
2364 int force_object_loose(const unsigned char *sha1, time_t mtime)
2365 {
2366 void *buf;
2367 unsigned long len;
2368 enum object_type type;
2369 char hdr[32];
2370 int hdrlen;
2371 int ret;
2372
2373 if (has_loose_object(sha1))
2374 return 0;
2375 buf = read_packed_sha1(sha1, &type, &len);
2376 if (!buf)
2377 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
2378 hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
2379 ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
2380 free(buf);
2381
2382 return ret;
2383 }
2384
2385 int has_pack_index(const unsigned char *sha1)
2386 {
2387 struct stat st;
2388 if (stat(sha1_pack_index_name(sha1), &st))
2389 return 0;
2390 return 1;
2391 }
2392
2393 int has_sha1_pack(const unsigned char *sha1)
2394 {
2395 struct pack_entry e;
2396 return find_pack_entry(sha1, &e);
2397 }
2398
2399 int has_sha1_file(const unsigned char *sha1)
2400 {
2401 struct pack_entry e;
2402
2403 if (find_pack_entry(sha1, &e))
2404 return 1;
2405 return has_loose_object(sha1);
2406 }
2407
2408 static int index_mem(unsigned char *sha1, void *buf, size_t size,
2409 int write_object, enum object_type type, const char *path)
2410 {
2411 int ret, re_allocated = 0;
2412
2413 if (!type)
2414 type = OBJ_BLOB;
2415
2416 /*
2417 * Convert blobs to git internal format
2418 */
2419 if ((type == OBJ_BLOB) && path) {
2420 struct strbuf nbuf = STRBUF_INIT;
2421 if (convert_to_git(path, buf, size, &nbuf,
2422 write_object ? safe_crlf : 0)) {
2423 buf = strbuf_detach(&nbuf, &size);
2424 re_allocated = 1;
2425 }
2426 }
2427
2428 if (write_object)
2429 ret = write_sha1_file(buf, size, typename(type), sha1);
2430 else
2431 ret = hash_sha1_file(buf, size, typename(type), sha1);
2432 if (re_allocated)
2433 free(buf);
2434 return ret;
2435 }
2436
2437 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
2438 enum object_type type, const char *path)
2439 {
2440 int ret;
2441 size_t size = xsize_t(st->st_size);
2442
2443 if (!S_ISREG(st->st_mode)) {
2444 struct strbuf sbuf = STRBUF_INIT;
2445 if (strbuf_read(&sbuf, fd, 4096) >= 0)
2446 ret = index_mem(sha1, sbuf.buf, sbuf.len, write_object,
2447 type, path);
2448 else
2449 ret = -1;
2450 strbuf_release(&sbuf);
2451 } else if (size) {
2452 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2453 ret = index_mem(sha1, buf, size, write_object, type, path);
2454 munmap(buf, size);
2455 } else
2456 ret = index_mem(sha1, NULL, size, write_object, type, path);
2457 close(fd);
2458 return ret;
2459 }
2460
2461 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
2462 {
2463 int fd;
2464 struct strbuf sb = STRBUF_INIT;
2465
2466 switch (st->st_mode & S_IFMT) {
2467 case S_IFREG:
2468 fd = open(path, O_RDONLY);
2469 if (fd < 0)
2470 return error("open(\"%s\"): %s", path,
2471 strerror(errno));
2472 if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
2473 return error("%s: failed to insert into database",
2474 path);
2475 break;
2476 case S_IFLNK:
2477 if (strbuf_readlink(&sb, path, st->st_size)) {
2478 char *errstr = strerror(errno);
2479 return error("readlink(\"%s\"): %s", path,
2480 errstr);
2481 }
2482 if (!write_object)
2483 hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
2484 else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
2485 return error("%s: failed to insert into database",
2486 path);
2487 strbuf_release(&sb);
2488 break;
2489 case S_IFDIR:
2490 return resolve_gitlink_ref(path, "HEAD", sha1);
2491 default:
2492 return error("%s: unsupported file type", path);
2493 }
2494 return 0;
2495 }
2496
2497 int read_pack_header(int fd, struct pack_header *header)
2498 {
2499 if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
2500 /* "eof before pack header was fully read" */
2501 return PH_ERROR_EOF;
2502
2503 if (header->hdr_signature != htonl(PACK_SIGNATURE))
2504 /* "protocol error (pack signature mismatch detected)" */
2505 return PH_ERROR_PACK_SIGNATURE;
2506 if (!pack_version_ok(header->hdr_version))
2507 /* "protocol error (pack version unsupported)" */
2508 return PH_ERROR_PROTOCOL;
2509 return 0;
2510 }