Tell which packfile is corrupt when we die.
[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 <sys/types.h>
10 #include <dirent.h>
11 #include "cache.h"
12 #include "delta.h"
13 #include "pack.h"
14
15 #ifndef O_NOATIME
16 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
17 #define O_NOATIME 01000000
18 #else
19 #define O_NOATIME 0
20 #endif
21 #endif
22
23 static unsigned int sha1_file_open_flag = O_NOATIME;
24
25 static unsigned hexval(char c)
26 {
27 if (c >= '0' && c <= '9')
28 return c - '0';
29 if (c >= 'a' && c <= 'f')
30 return c - 'a' + 10;
31 if (c >= 'A' && c <= 'F')
32 return c - 'A' + 10;
33 return ~0;
34 }
35
36 int get_sha1_hex(const char *hex, unsigned char *sha1)
37 {
38 int i;
39 for (i = 0; i < 20; i++) {
40 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
41 if (val & ~0xff)
42 return -1;
43 *sha1++ = val;
44 hex += 2;
45 }
46 return 0;
47 }
48
49 static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir,
50 *git_graft_file;
51 static void setup_git_env(void)
52 {
53 git_dir = getenv(GIT_DIR_ENVIRONMENT);
54 if (!git_dir)
55 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
56 git_object_dir = getenv(DB_ENVIRONMENT);
57 if (!git_object_dir) {
58 git_object_dir = xmalloc(strlen(git_dir) + 9);
59 sprintf(git_object_dir, "%s/objects", git_dir);
60 }
61 git_refs_dir = xmalloc(strlen(git_dir) + 6);
62 sprintf(git_refs_dir, "%s/refs", git_dir);
63 git_index_file = getenv(INDEX_ENVIRONMENT);
64 if (!git_index_file) {
65 git_index_file = xmalloc(strlen(git_dir) + 7);
66 sprintf(git_index_file, "%s/index", git_dir);
67 }
68 git_graft_file = getenv(GRAFT_ENVIRONMENT);
69 if (!git_graft_file)
70 git_graft_file = strdup(git_path("info/grafts"));
71 }
72
73 char *get_git_dir(void)
74 {
75 if (!git_dir)
76 setup_git_env();
77 return git_dir;
78 }
79
80 char *get_object_directory(void)
81 {
82 if (!git_object_dir)
83 setup_git_env();
84 return git_object_dir;
85 }
86
87 char *get_refs_directory(void)
88 {
89 if (!git_refs_dir)
90 setup_git_env();
91 return git_refs_dir;
92 }
93
94 char *get_index_file(void)
95 {
96 if (!git_index_file)
97 setup_git_env();
98 return git_index_file;
99 }
100
101 char *get_graft_file(void)
102 {
103 if (!git_graft_file)
104 setup_git_env();
105 return git_graft_file;
106 }
107
108 int safe_create_leading_directories(char *path)
109 {
110 char *pos = path;
111
112 while (pos) {
113 pos = strchr(pos, '/');
114 if (!pos)
115 break;
116 *pos = 0;
117 if (mkdir(path, 0777) < 0)
118 if (errno != EEXIST) {
119 *pos = '/';
120 return -1;
121 }
122 *pos++ = '/';
123 }
124 return 0;
125 }
126
127 char * sha1_to_hex(const unsigned char *sha1)
128 {
129 static char buffer[50];
130 static const char hex[] = "0123456789abcdef";
131 char *buf = buffer;
132 int i;
133
134 for (i = 0; i < 20; i++) {
135 unsigned int val = *sha1++;
136 *buf++ = hex[val >> 4];
137 *buf++ = hex[val & 0xf];
138 }
139 return buffer;
140 }
141
142 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
143 {
144 int i;
145 for (i = 0; i < 20; i++) {
146 static char hex[] = "0123456789abcdef";
147 unsigned int val = sha1[i];
148 char *pos = pathbuf + i*2 + (i > 0);
149 *pos++ = hex[val >> 4];
150 *pos = hex[val & 0xf];
151 }
152 }
153
154 /*
155 * NOTE! This returns a statically allocated buffer, so you have to be
156 * careful about using it. Do a "strdup()" if you need to save the
157 * filename.
158 *
159 * Also note that this returns the location for creating. Reading
160 * SHA1 file can happen from any alternate directory listed in the
161 * DB_ENVIRONMENT environment variable if it is not found in
162 * the primary object database.
163 */
164 char *sha1_file_name(const unsigned char *sha1)
165 {
166 static char *name, *base;
167
168 if (!base) {
169 const char *sha1_file_directory = get_object_directory();
170 int len = strlen(sha1_file_directory);
171 base = xmalloc(len + 60);
172 memcpy(base, sha1_file_directory, len);
173 memset(base+len, 0, 60);
174 base[len] = '/';
175 base[len+3] = '/';
176 name = base + len + 1;
177 }
178 fill_sha1_path(name, sha1);
179 return base;
180 }
181
182 char *sha1_pack_name(const unsigned char *sha1)
183 {
184 static const char hex[] = "0123456789abcdef";
185 static char *name, *base, *buf;
186 int i;
187
188 if (!base) {
189 const char *sha1_file_directory = get_object_directory();
190 int len = strlen(sha1_file_directory);
191 base = xmalloc(len + 60);
192 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
193 name = base + len + 11;
194 }
195
196 buf = name;
197
198 for (i = 0; i < 20; i++) {
199 unsigned int val = *sha1++;
200 *buf++ = hex[val >> 4];
201 *buf++ = hex[val & 0xf];
202 }
203
204 return base;
205 }
206
207 char *sha1_pack_index_name(const unsigned char *sha1)
208 {
209 static const char hex[] = "0123456789abcdef";
210 static char *name, *base, *buf;
211 int i;
212
213 if (!base) {
214 const char *sha1_file_directory = get_object_directory();
215 int len = strlen(sha1_file_directory);
216 base = xmalloc(len + 60);
217 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
218 name = base + len + 11;
219 }
220
221 buf = name;
222
223 for (i = 0; i < 20; i++) {
224 unsigned int val = *sha1++;
225 *buf++ = hex[val >> 4];
226 *buf++ = hex[val & 0xf];
227 }
228
229 return base;
230 }
231
232 struct alternate_object_database *alt_odb_list;
233 static struct alternate_object_database **alt_odb_tail;
234
235 /*
236 * Prepare alternate object database registry.
237 *
238 * The variable alt_odb_list points at the list of struct
239 * alternate_object_database. The elements on this list come from
240 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
241 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
242 * whose contents is exactly in the same format as that environment
243 * variable. Its base points at a statically allocated buffer that
244 * contains "/the/directory/corresponding/to/.git/objects/...", while
245 * its name points just after the slash at the end of ".git/objects/"
246 * in the example above, and has enough space to hold 40-byte hex
247 * SHA1, an extra slash for the first level indirection, and the
248 * terminating NUL.
249 */
250 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
251 const char *relative_base)
252 {
253 const char *cp, *last;
254 struct alternate_object_database *ent;
255 int base_len = -1;
256
257 last = alt;
258 while (last < ep) {
259 cp = last;
260 if (cp < ep && *cp == '#') {
261 while (cp < ep && *cp != sep)
262 cp++;
263 last = cp + 1;
264 continue;
265 }
266 for ( ; cp < ep && *cp != sep; cp++)
267 ;
268 if (last != cp) {
269 /* 43 = 40-byte + 2 '/' + terminating NUL */
270 int pfxlen = cp - last;
271 int entlen = pfxlen + 43;
272
273 if (*last != '/' && relative_base) {
274 /* Relative alt-odb */
275 if (base_len < 0)
276 base_len = strlen(relative_base) + 1;
277 entlen += base_len;
278 pfxlen += base_len;
279 }
280 ent = xmalloc(sizeof(*ent) + entlen);
281 *alt_odb_tail = ent;
282 alt_odb_tail = &(ent->next);
283 ent->next = NULL;
284 if (*last != '/' && relative_base) {
285 memcpy(ent->base, relative_base, base_len - 1);
286 ent->base[base_len - 1] = '/';
287 memcpy(ent->base + base_len,
288 last, cp - last);
289 }
290 else
291 memcpy(ent->base, last, pfxlen);
292 ent->name = ent->base + pfxlen + 1;
293 ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
294 ent->base[entlen-1] = 0;
295 }
296 while (cp < ep && *cp == sep)
297 cp++;
298 last = cp;
299 }
300 }
301
302 void prepare_alt_odb(void)
303 {
304 char path[PATH_MAX];
305 char *map;
306 int fd;
307 struct stat st;
308 char *alt;
309
310 alt = getenv(ALTERNATE_DB_ENVIRONMENT);
311 if (!alt) alt = "";
312
313 if (alt_odb_tail)
314 return;
315 alt_odb_tail = &alt_odb_list;
316 link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
317
318 sprintf(path, "%s/info/alternates", get_object_directory());
319 fd = open(path, O_RDONLY);
320 if (fd < 0)
321 return;
322 if (fstat(fd, &st) || (st.st_size == 0)) {
323 close(fd);
324 return;
325 }
326 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
327 close(fd);
328 if (map == MAP_FAILED)
329 return;
330
331 link_alt_odb_entries(map, map + st.st_size, '\n',
332 get_object_directory());
333 munmap(map, st.st_size);
334 }
335
336 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
337 {
338 char *name = sha1_file_name(sha1);
339 struct alternate_object_database *alt;
340
341 if (!stat(name, st))
342 return name;
343 prepare_alt_odb();
344 for (alt = alt_odb_list; alt; alt = alt->next) {
345 name = alt->name;
346 fill_sha1_path(name, sha1);
347 if (!stat(alt->base, st))
348 return alt->base;
349 }
350 return NULL;
351 }
352
353 #define PACK_MAX_SZ (1<<26)
354 static int pack_used_ctr;
355 static unsigned long pack_mapped;
356 struct packed_git *packed_git;
357
358 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
359 void **idx_map_)
360 {
361 void *idx_map;
362 unsigned int *index;
363 unsigned long idx_size;
364 int nr, i;
365 int fd = open(path, O_RDONLY);
366 struct stat st;
367 if (fd < 0)
368 return -1;
369 if (fstat(fd, &st)) {
370 close(fd);
371 return -1;
372 }
373 idx_size = st.st_size;
374 idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
375 close(fd);
376 if (idx_map == MAP_FAILED)
377 return -1;
378
379 index = idx_map;
380 *idx_map_ = idx_map;
381 *idx_size_ = idx_size;
382
383 /* check index map */
384 if (idx_size < 4*256 + 20 + 20)
385 return error("index file too small");
386 nr = 0;
387 for (i = 0; i < 256; i++) {
388 unsigned int n = ntohl(index[i]);
389 if (n < nr)
390 return error("non-monotonic index");
391 nr = n;
392 }
393
394 /*
395 * Total size:
396 * - 256 index entries 4 bytes each
397 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
398 * - 20-byte SHA1 of the packfile
399 * - 20-byte SHA1 file checksum
400 */
401 if (idx_size != 4*256 + nr * 24 + 20 + 20)
402 return error("wrong index file size");
403
404 return 0;
405 }
406
407 static int unuse_one_packed_git(void)
408 {
409 struct packed_git *p, *lru = NULL;
410
411 for (p = packed_git; p; p = p->next) {
412 if (p->pack_use_cnt || !p->pack_base)
413 continue;
414 if (!lru || p->pack_last_used < lru->pack_last_used)
415 lru = p;
416 }
417 if (!lru)
418 return 0;
419 munmap(lru->pack_base, lru->pack_size);
420 lru->pack_base = NULL;
421 return 1;
422 }
423
424 void unuse_packed_git(struct packed_git *p)
425 {
426 p->pack_use_cnt--;
427 }
428
429 int use_packed_git(struct packed_git *p)
430 {
431 if (!p->pack_size) {
432 struct stat st;
433 // We created the struct before we had the pack
434 stat(p->pack_name, &st);
435 if (!S_ISREG(st.st_mode))
436 die("packfile %s not a regular file", p->pack_name);
437 p->pack_size = st.st_size;
438 }
439 if (!p->pack_base) {
440 int fd;
441 struct stat st;
442 void *map;
443
444 pack_mapped += p->pack_size;
445 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
446 ; /* nothing */
447 fd = open(p->pack_name, O_RDONLY);
448 if (fd < 0)
449 die("packfile %s cannot be opened", p->pack_name);
450 if (fstat(fd, &st)) {
451 close(fd);
452 die("packfile %s cannot be opened", p->pack_name);
453 }
454 if (st.st_size != p->pack_size)
455 die("packfile %s size mismatch.", p->pack_name);
456 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
457 close(fd);
458 if (map == MAP_FAILED)
459 die("packfile %s cannot be mapped.", p->pack_name);
460 p->pack_base = map;
461
462 /* Check if the pack file matches with the index file.
463 * this is cheap.
464 */
465 if (memcmp((char*)(p->index_base) + p->index_size - 40,
466 p->pack_base + p->pack_size - 20, 20)) {
467
468 die("packfile %s does not match index.", p->pack_name);
469 }
470 }
471 p->pack_last_used = pack_used_ctr++;
472 p->pack_use_cnt++;
473 return 0;
474 }
475
476 struct packed_git *add_packed_git(char *path, int path_len)
477 {
478 struct stat st;
479 struct packed_git *p;
480 unsigned long idx_size;
481 void *idx_map;
482
483 if (check_packed_git_idx(path, &idx_size, &idx_map))
484 return NULL;
485
486 /* do we have a corresponding .pack file? */
487 strcpy(path + path_len - 4, ".pack");
488 if (stat(path, &st) || !S_ISREG(st.st_mode)) {
489 munmap(idx_map, idx_size);
490 return NULL;
491 }
492 /* ok, it looks sane as far as we can check without
493 * actually mapping the pack file.
494 */
495 p = xmalloc(sizeof(*p) + path_len + 2);
496 strcpy(p->pack_name, path);
497 p->index_size = idx_size;
498 p->pack_size = st.st_size;
499 p->index_base = idx_map;
500 p->next = NULL;
501 p->pack_base = NULL;
502 p->pack_last_used = 0;
503 p->pack_use_cnt = 0;
504 return p;
505 }
506
507 struct packed_git *parse_pack_index(unsigned char *sha1)
508 {
509 char *path = sha1_pack_index_name(sha1);
510 return parse_pack_index_file(sha1, path);
511 }
512
513 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
514 {
515 struct packed_git *p;
516 unsigned long idx_size;
517 void *idx_map;
518 char *path;
519
520 if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
521 return NULL;
522
523 path = sha1_pack_name(sha1);
524
525 p = xmalloc(sizeof(*p) + strlen(path) + 2);
526 strcpy(p->pack_name, path);
527 p->index_size = idx_size;
528 p->pack_size = 0;
529 p->index_base = idx_map;
530 p->next = NULL;
531 p->pack_base = NULL;
532 p->pack_last_used = 0;
533 p->pack_use_cnt = 0;
534 memcpy(p->sha1, sha1, 20);
535 return p;
536 }
537
538 void install_packed_git(struct packed_git *pack)
539 {
540 pack->next = packed_git;
541 packed_git = pack;
542 }
543
544 static void prepare_packed_git_one(char *objdir)
545 {
546 char path[PATH_MAX];
547 int len;
548 DIR *dir;
549 struct dirent *de;
550
551 sprintf(path, "%s/pack", objdir);
552 len = strlen(path);
553 dir = opendir(path);
554 if (!dir)
555 return;
556 path[len++] = '/';
557 while ((de = readdir(dir)) != NULL) {
558 int namelen = strlen(de->d_name);
559 struct packed_git *p;
560
561 if (strcmp(de->d_name + namelen - 4, ".idx"))
562 continue;
563
564 /* we have .idx. Is it a file we can map? */
565 strcpy(path + len, de->d_name);
566 p = add_packed_git(path, len + namelen);
567 if (!p)
568 continue;
569 p->next = packed_git;
570 packed_git = p;
571 }
572 closedir(dir);
573 }
574
575 void prepare_packed_git(void)
576 {
577 static int run_once = 0;
578 struct alternate_object_database *alt;
579
580 if (run_once)
581 return;
582 prepare_packed_git_one(get_object_directory());
583 prepare_alt_odb();
584 for (alt = alt_odb_list; alt; alt = alt->next) {
585 alt->name[0] = 0;
586 prepare_packed_git_one(alt->base);
587 }
588 run_once = 1;
589 }
590
591 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
592 {
593 char header[100];
594 unsigned char real_sha1[20];
595 SHA_CTX c;
596
597 SHA1_Init(&c);
598 SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
599 SHA1_Update(&c, map, size);
600 SHA1_Final(real_sha1, &c);
601 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
602 }
603
604 static void *map_sha1_file_internal(const unsigned char *sha1,
605 unsigned long *size)
606 {
607 struct stat st;
608 void *map;
609 int fd;
610 char *filename = find_sha1_file(sha1, &st);
611
612 if (!filename) {
613 return NULL;
614 }
615
616 fd = open(filename, O_RDONLY | sha1_file_open_flag);
617 if (fd < 0) {
618 /* See if it works without O_NOATIME */
619 switch (sha1_file_open_flag) {
620 default:
621 fd = open(filename, O_RDONLY);
622 if (fd >= 0)
623 break;
624 /* Fallthrough */
625 case 0:
626 return NULL;
627 }
628
629 /* If it failed once, it will probably fail again.
630 * Stop using O_NOATIME
631 */
632 sha1_file_open_flag = 0;
633 }
634 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
635 close(fd);
636 if (map == MAP_FAILED)
637 return NULL;
638 *size = st.st_size;
639 return map;
640 }
641
642 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
643 {
644 /* Get the data stream */
645 memset(stream, 0, sizeof(*stream));
646 stream->next_in = map;
647 stream->avail_in = mapsize;
648 stream->next_out = buffer;
649 stream->avail_out = size;
650
651 inflateInit(stream);
652 return inflate(stream, 0);
653 }
654
655 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
656 {
657 int bytes = strlen(buffer) + 1;
658 unsigned char *buf = xmalloc(1+size);
659
660 memcpy(buf, buffer + bytes, stream->total_out - bytes);
661 bytes = stream->total_out - bytes;
662 if (bytes < size) {
663 stream->next_out = buf + bytes;
664 stream->avail_out = size - bytes;
665 while (inflate(stream, Z_FINISH) == Z_OK)
666 /* nothing */;
667 }
668 buf[size] = 0;
669 inflateEnd(stream);
670 return buf;
671 }
672
673 /*
674 * We used to just use "sscanf()", but that's actually way
675 * too permissive for what we want to check. So do an anal
676 * object header parse by hand.
677 */
678 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
679 {
680 int i;
681 unsigned long size;
682
683 /*
684 * The type can be at most ten bytes (including the
685 * terminating '\0' that we add), and is followed by
686 * a space.
687 */
688 i = 10;
689 for (;;) {
690 char c = *hdr++;
691 if (c == ' ')
692 break;
693 if (!--i)
694 return -1;
695 *type++ = c;
696 }
697 *type = 0;
698
699 /*
700 * The length must follow immediately, and be in canonical
701 * decimal format (ie "010" is not valid).
702 */
703 size = *hdr++ - '0';
704 if (size > 9)
705 return -1;
706 if (size) {
707 for (;;) {
708 unsigned long c = *hdr - '0';
709 if (c > 9)
710 break;
711 hdr++;
712 size = size * 10 + c;
713 }
714 }
715 *sizep = size;
716
717 /*
718 * The length must be followed by a zero byte
719 */
720 return *hdr ? -1 : 0;
721 }
722
723 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
724 {
725 int ret;
726 z_stream stream;
727 char hdr[8192];
728
729 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
730 if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
731 return NULL;
732
733 return unpack_sha1_rest(&stream, hdr, *size);
734 }
735
736 /* forward declaration for a mutually recursive function */
737 static int packed_object_info(struct pack_entry *entry,
738 char *type, unsigned long *sizep);
739
740 static int packed_delta_info(unsigned char *base_sha1,
741 unsigned long delta_size,
742 unsigned long left,
743 char *type,
744 unsigned long *sizep,
745 struct packed_git *p)
746 {
747 struct pack_entry base_ent;
748
749 if (left < 20)
750 die("truncated pack file");
751
752 /* The base entry _must_ be in the same pack */
753 if (!find_pack_entry_one(base_sha1, &base_ent, p))
754 die("failed to find delta-pack base object %s",
755 sha1_to_hex(base_sha1));
756
757 /* We choose to only get the type of the base object and
758 * ignore potentially corrupt pack file that expects the delta
759 * based on a base with a wrong size. This saves tons of
760 * inflate() calls.
761 */
762
763 if (packed_object_info(&base_ent, type, NULL))
764 die("cannot get info for delta-pack base");
765
766 if (sizep) {
767 const unsigned char *data;
768 unsigned char delta_head[64];
769 unsigned long result_size;
770 z_stream stream;
771 int st;
772
773 memset(&stream, 0, sizeof(stream));
774
775 data = stream.next_in = base_sha1 + 20;
776 stream.avail_in = left - 20;
777 stream.next_out = delta_head;
778 stream.avail_out = sizeof(delta_head);
779
780 inflateInit(&stream);
781 st = inflate(&stream, Z_FINISH);
782 inflateEnd(&stream);
783 if ((st != Z_STREAM_END) &&
784 stream.total_out != sizeof(delta_head))
785 die("delta data unpack-initial failed");
786
787 /* Examine the initial part of the delta to figure out
788 * the result size.
789 */
790 data = delta_head;
791 get_delta_hdr_size(&data); /* ignore base size */
792
793 /* Read the result size */
794 result_size = get_delta_hdr_size(&data);
795 *sizep = result_size;
796 }
797 return 0;
798 }
799
800 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
801 enum object_type *type, unsigned long *sizep)
802 {
803 unsigned shift;
804 unsigned char *pack, c;
805 unsigned long size;
806
807 if (offset >= p->pack_size)
808 die("object offset outside of pack file");
809
810 pack = p->pack_base + offset;
811 c = *pack++;
812 offset++;
813 *type = (c >> 4) & 7;
814 size = c & 15;
815 shift = 4;
816 while (c & 0x80) {
817 if (offset >= p->pack_size)
818 die("object offset outside of pack file");
819 c = *pack++;
820 offset++;
821 size += (c & 0x7f) << shift;
822 shift += 7;
823 }
824 *sizep = size;
825 return offset;
826 }
827
828 void packed_object_info_detail(struct pack_entry *e,
829 char *type,
830 unsigned long *size,
831 unsigned long *store_size,
832 int *delta_chain_length,
833 unsigned char *base_sha1)
834 {
835 struct packed_git *p = e->p;
836 unsigned long offset, left;
837 unsigned char *pack;
838 enum object_type kind;
839
840 offset = unpack_object_header(p, e->offset, &kind, size);
841 pack = p->pack_base + offset;
842 left = p->pack_size - offset;
843 if (kind != OBJ_DELTA)
844 *delta_chain_length = 0;
845 else {
846 int chain_length = 0;
847 memcpy(base_sha1, pack, 20);
848 do {
849 struct pack_entry base_ent;
850 unsigned long junk;
851
852 find_pack_entry_one(pack, &base_ent, p);
853 offset = unpack_object_header(p, base_ent.offset,
854 &kind, &junk);
855 pack = p->pack_base + offset;
856 chain_length++;
857 } while (kind == OBJ_DELTA);
858 *delta_chain_length = chain_length;
859 }
860 switch (kind) {
861 case OBJ_COMMIT:
862 strcpy(type, "commit");
863 break;
864 case OBJ_TREE:
865 strcpy(type, "tree");
866 break;
867 case OBJ_BLOB:
868 strcpy(type, "blob");
869 break;
870 case OBJ_TAG:
871 strcpy(type, "tag");
872 break;
873 default:
874 die("corrupted pack file %s containing object of kind %d",
875 p->pack_name, kind);
876 }
877 *store_size = 0; /* notyet */
878 }
879
880 static int packed_object_info(struct pack_entry *entry,
881 char *type, unsigned long *sizep)
882 {
883 struct packed_git *p = entry->p;
884 unsigned long offset, size, left;
885 unsigned char *pack;
886 enum object_type kind;
887 int retval;
888
889 if (use_packed_git(p))
890 die("cannot map packed file");
891
892 offset = unpack_object_header(p, entry->offset, &kind, &size);
893 pack = p->pack_base + offset;
894 left = p->pack_size - offset;
895
896 switch (kind) {
897 case OBJ_DELTA:
898 retval = packed_delta_info(pack, size, left, type, sizep, p);
899 unuse_packed_git(p);
900 return retval;
901 case OBJ_COMMIT:
902 strcpy(type, "commit");
903 break;
904 case OBJ_TREE:
905 strcpy(type, "tree");
906 break;
907 case OBJ_BLOB:
908 strcpy(type, "blob");
909 break;
910 case OBJ_TAG:
911 strcpy(type, "tag");
912 break;
913 default:
914 die("corrupted pack file %s containing object of kind %d",
915 p->pack_name, kind);
916 }
917 if (sizep)
918 *sizep = size;
919 unuse_packed_git(p);
920 return 0;
921 }
922
923 /* forward declaration for a mutually recursive function */
924 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
925
926 static void *unpack_delta_entry(unsigned char *base_sha1,
927 unsigned long delta_size,
928 unsigned long left,
929 char *type,
930 unsigned long *sizep,
931 struct packed_git *p)
932 {
933 struct pack_entry base_ent;
934 void *data, *delta_data, *result, *base;
935 unsigned long data_size, result_size, base_size;
936 z_stream stream;
937 int st;
938
939 if (left < 20)
940 die("truncated pack file");
941 data = base_sha1 + 20;
942 data_size = left - 20;
943 delta_data = xmalloc(delta_size);
944
945 memset(&stream, 0, sizeof(stream));
946
947 stream.next_in = data;
948 stream.avail_in = data_size;
949 stream.next_out = delta_data;
950 stream.avail_out = delta_size;
951
952 inflateInit(&stream);
953 st = inflate(&stream, Z_FINISH);
954 inflateEnd(&stream);
955 if ((st != Z_STREAM_END) || stream.total_out != delta_size)
956 die("delta data unpack failed");
957
958 /* The base entry _must_ be in the same pack */
959 if (!find_pack_entry_one(base_sha1, &base_ent, p))
960 die("failed to find delta-pack base object %s",
961 sha1_to_hex(base_sha1));
962 base = unpack_entry_gently(&base_ent, type, &base_size);
963 if (!base)
964 die("failed to read delta-pack base object %s",
965 sha1_to_hex(base_sha1));
966 result = patch_delta(base, base_size,
967 delta_data, delta_size,
968 &result_size);
969 if (!result)
970 die("failed to apply delta");
971 free(delta_data);
972 free(base);
973 *sizep = result_size;
974 return result;
975 }
976
977 static void *unpack_non_delta_entry(unsigned char *data,
978 unsigned long size,
979 unsigned long left)
980 {
981 int st;
982 z_stream stream;
983 unsigned char *buffer;
984
985 buffer = xmalloc(size + 1);
986 buffer[size] = 0;
987 memset(&stream, 0, sizeof(stream));
988 stream.next_in = data;
989 stream.avail_in = left;
990 stream.next_out = buffer;
991 stream.avail_out = size;
992
993 inflateInit(&stream);
994 st = inflate(&stream, Z_FINISH);
995 inflateEnd(&stream);
996 if ((st != Z_STREAM_END) || stream.total_out != size) {
997 free(buffer);
998 return NULL;
999 }
1000
1001 return buffer;
1002 }
1003
1004 static void *unpack_entry(struct pack_entry *entry,
1005 char *type, unsigned long *sizep)
1006 {
1007 struct packed_git *p = entry->p;
1008 void *retval;
1009
1010 if (use_packed_git(p))
1011 die("cannot map packed file");
1012 retval = unpack_entry_gently(entry, type, sizep);
1013 unuse_packed_git(p);
1014 if (!retval)
1015 die("corrupted pack file %s", p->pack_name);
1016 return retval;
1017 }
1018
1019 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1020 void *unpack_entry_gently(struct pack_entry *entry,
1021 char *type, unsigned long *sizep)
1022 {
1023 struct packed_git *p = entry->p;
1024 unsigned long offset, size, left;
1025 unsigned char *pack;
1026 enum object_type kind;
1027 void *retval;
1028
1029 offset = unpack_object_header(p, entry->offset, &kind, &size);
1030 pack = p->pack_base + offset;
1031 left = p->pack_size - offset;
1032 switch (kind) {
1033 case OBJ_DELTA:
1034 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1035 return retval;
1036 case OBJ_COMMIT:
1037 strcpy(type, "commit");
1038 break;
1039 case OBJ_TREE:
1040 strcpy(type, "tree");
1041 break;
1042 case OBJ_BLOB:
1043 strcpy(type, "blob");
1044 break;
1045 case OBJ_TAG:
1046 strcpy(type, "tag");
1047 break;
1048 default:
1049 return NULL;
1050 }
1051 *sizep = size;
1052 retval = unpack_non_delta_entry(pack, size, left);
1053 return retval;
1054 }
1055
1056 int num_packed_objects(const struct packed_git *p)
1057 {
1058 /* See check_packed_git_idx() */
1059 return (p->index_size - 20 - 20 - 4*256) / 24;
1060 }
1061
1062 int nth_packed_object_sha1(const struct packed_git *p, int n,
1063 unsigned char* sha1)
1064 {
1065 void *index = p->index_base + 256;
1066 if (n < 0 || num_packed_objects(p) <= n)
1067 return -1;
1068 memcpy(sha1, (index + 24 * n + 4), 20);
1069 return 0;
1070 }
1071
1072 int find_pack_entry_one(const unsigned char *sha1,
1073 struct pack_entry *e, struct packed_git *p)
1074 {
1075 unsigned int *level1_ofs = p->index_base;
1076 int hi = ntohl(level1_ofs[*sha1]);
1077 int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1078 void *index = p->index_base + 256;
1079
1080 do {
1081 int mi = (lo + hi) / 2;
1082 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1083 if (!cmp) {
1084 e->offset = ntohl(*((int*)(index + 24 * mi)));
1085 memcpy(e->sha1, sha1, 20);
1086 e->p = p;
1087 return 1;
1088 }
1089 if (cmp > 0)
1090 hi = mi;
1091 else
1092 lo = mi+1;
1093 } while (lo < hi);
1094 return 0;
1095 }
1096
1097 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1098 {
1099 struct packed_git *p;
1100 prepare_packed_git();
1101
1102 for (p = packed_git; p; p = p->next) {
1103 if (find_pack_entry_one(sha1, e, p))
1104 return 1;
1105 }
1106 return 0;
1107 }
1108
1109 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1110 struct packed_git *packs)
1111 {
1112 struct packed_git *p;
1113 struct pack_entry e;
1114
1115 for (p = packs; p; p = p->next) {
1116 if (find_pack_entry_one(sha1, &e, p))
1117 return p;
1118 }
1119 return NULL;
1120
1121 }
1122
1123 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1124 {
1125 int status;
1126 unsigned long mapsize, size;
1127 void *map;
1128 z_stream stream;
1129 char hdr[128];
1130
1131 map = map_sha1_file_internal(sha1, &mapsize);
1132 if (!map) {
1133 struct pack_entry e;
1134
1135 if (!find_pack_entry(sha1, &e))
1136 return error("unable to find %s", sha1_to_hex(sha1));
1137 return packed_object_info(&e, type, sizep);
1138 }
1139 if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1140 status = error("unable to unpack %s header",
1141 sha1_to_hex(sha1));
1142 if (parse_sha1_header(hdr, type, &size) < 0)
1143 status = error("unable to parse %s header", sha1_to_hex(sha1));
1144 else {
1145 status = 0;
1146 if (sizep)
1147 *sizep = size;
1148 }
1149 inflateEnd(&stream);
1150 munmap(map, mapsize);
1151 return status;
1152 }
1153
1154 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1155 {
1156 struct pack_entry e;
1157
1158 if (!find_pack_entry(sha1, &e)) {
1159 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1160 return NULL;
1161 }
1162 return unpack_entry(&e, type, size);
1163 }
1164
1165 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1166 {
1167 unsigned long mapsize;
1168 void *map, *buf;
1169 struct pack_entry e;
1170
1171 if (find_pack_entry(sha1, &e))
1172 return read_packed_sha1(sha1, type, size);
1173 map = map_sha1_file_internal(sha1, &mapsize);
1174 if (map) {
1175 buf = unpack_sha1_file(map, mapsize, type, size);
1176 munmap(map, mapsize);
1177 return buf;
1178 }
1179 return NULL;
1180 }
1181
1182 void *read_object_with_reference(const unsigned char *sha1,
1183 const char *required_type,
1184 unsigned long *size,
1185 unsigned char *actual_sha1_return)
1186 {
1187 char type[20];
1188 void *buffer;
1189 unsigned long isize;
1190 unsigned char actual_sha1[20];
1191
1192 memcpy(actual_sha1, sha1, 20);
1193 while (1) {
1194 int ref_length = -1;
1195 const char *ref_type = NULL;
1196
1197 buffer = read_sha1_file(actual_sha1, type, &isize);
1198 if (!buffer)
1199 return NULL;
1200 if (!strcmp(type, required_type)) {
1201 *size = isize;
1202 if (actual_sha1_return)
1203 memcpy(actual_sha1_return, actual_sha1, 20);
1204 return buffer;
1205 }
1206 /* Handle references */
1207 else if (!strcmp(type, "commit"))
1208 ref_type = "tree ";
1209 else if (!strcmp(type, "tag"))
1210 ref_type = "object ";
1211 else {
1212 free(buffer);
1213 return NULL;
1214 }
1215 ref_length = strlen(ref_type);
1216
1217 if (memcmp(buffer, ref_type, ref_length) ||
1218 get_sha1_hex(buffer + ref_length, actual_sha1)) {
1219 free(buffer);
1220 return NULL;
1221 }
1222 free(buffer);
1223 /* Now we have the ID of the referred-to object in
1224 * actual_sha1. Check again. */
1225 }
1226 }
1227
1228 char *write_sha1_file_prepare(void *buf,
1229 unsigned long len,
1230 const char *type,
1231 unsigned char *sha1,
1232 unsigned char *hdr,
1233 int *hdrlen)
1234 {
1235 SHA_CTX c;
1236
1237 /* Generate the header */
1238 *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1239
1240 /* Sha1.. */
1241 SHA1_Init(&c);
1242 SHA1_Update(&c, hdr, *hdrlen);
1243 SHA1_Update(&c, buf, len);
1244 SHA1_Final(sha1, &c);
1245
1246 return sha1_file_name(sha1);
1247 }
1248
1249 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1250 {
1251 int size;
1252 unsigned char *compressed;
1253 z_stream stream;
1254 unsigned char sha1[20];
1255 char *filename;
1256 static char tmpfile[PATH_MAX];
1257 unsigned char hdr[50];
1258 int fd, hdrlen, ret;
1259
1260 /* Normally if we have it in the pack then we do not bother writing
1261 * it out into .git/objects/??/?{38} file.
1262 */
1263 filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1264 if (returnsha1)
1265 memcpy(returnsha1, sha1, 20);
1266 if (has_sha1_file(sha1))
1267 return 0;
1268 fd = open(filename, O_RDONLY);
1269 if (fd >= 0) {
1270 /*
1271 * FIXME!!! We might do collision checking here, but we'd
1272 * need to uncompress the old file and check it. Later.
1273 */
1274 close(fd);
1275 return 0;
1276 }
1277
1278 if (errno != ENOENT) {
1279 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1280 return -1;
1281 }
1282
1283 snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1284
1285 fd = mkstemp(tmpfile);
1286 if (fd < 0) {
1287 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1288 return -1;
1289 }
1290
1291 /* Set it up */
1292 memset(&stream, 0, sizeof(stream));
1293 deflateInit(&stream, Z_BEST_COMPRESSION);
1294 size = deflateBound(&stream, len+hdrlen);
1295 compressed = xmalloc(size);
1296
1297 /* Compress it */
1298 stream.next_out = compressed;
1299 stream.avail_out = size;
1300
1301 /* First header.. */
1302 stream.next_in = hdr;
1303 stream.avail_in = hdrlen;
1304 while (deflate(&stream, 0) == Z_OK)
1305 /* nothing */;
1306
1307 /* Then the data itself.. */
1308 stream.next_in = buf;
1309 stream.avail_in = len;
1310 while (deflate(&stream, Z_FINISH) == Z_OK)
1311 /* nothing */;
1312 deflateEnd(&stream);
1313 size = stream.total_out;
1314
1315 if (write(fd, compressed, size) != size)
1316 die("unable to write file");
1317 fchmod(fd, 0444);
1318 close(fd);
1319 free(compressed);
1320
1321 ret = link(tmpfile, filename);
1322 if (ret < 0) {
1323 ret = errno;
1324
1325 /*
1326 * Coda hack - coda doesn't like cross-directory links,
1327 * so we fall back to a rename, which will mean that it
1328 * won't be able to check collisions, but that's not a
1329 * big deal.
1330 *
1331 * When this succeeds, we just return 0. We have nothing
1332 * left to unlink.
1333 */
1334 if (ret == EXDEV && !rename(tmpfile, filename))
1335 return 0;
1336 }
1337 unlink(tmpfile);
1338 if (ret) {
1339 if (ret != EEXIST) {
1340 fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1341 return -1;
1342 }
1343 /* FIXME!!! Collision check here ? */
1344 }
1345
1346 return 0;
1347 }
1348
1349 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1350 {
1351 ssize_t size;
1352 unsigned long objsize;
1353 int posn = 0;
1354 void *map = map_sha1_file_internal(sha1, &objsize);
1355 void *buf = map;
1356 void *temp_obj = NULL;
1357 z_stream stream;
1358
1359 if (!buf) {
1360 unsigned char *unpacked;
1361 unsigned long len;
1362 char type[20];
1363 char hdr[50];
1364 int hdrlen;
1365 // need to unpack and recompress it by itself
1366 unpacked = read_packed_sha1(sha1, type, &len);
1367
1368 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1369
1370 /* Set it up */
1371 memset(&stream, 0, sizeof(stream));
1372 deflateInit(&stream, Z_BEST_COMPRESSION);
1373 size = deflateBound(&stream, len + hdrlen);
1374 temp_obj = buf = xmalloc(size);
1375
1376 /* Compress it */
1377 stream.next_out = buf;
1378 stream.avail_out = size;
1379
1380 /* First header.. */
1381 stream.next_in = (void *)hdr;
1382 stream.avail_in = hdrlen;
1383 while (deflate(&stream, 0) == Z_OK)
1384 /* nothing */;
1385
1386 /* Then the data itself.. */
1387 stream.next_in = unpacked;
1388 stream.avail_in = len;
1389 while (deflate(&stream, Z_FINISH) == Z_OK)
1390 /* nothing */;
1391 deflateEnd(&stream);
1392 free(unpacked);
1393
1394 objsize = stream.total_out;
1395 }
1396
1397 do {
1398 size = write(fd, buf + posn, objsize - posn);
1399 if (size <= 0) {
1400 if (!size) {
1401 fprintf(stderr, "write closed");
1402 } else {
1403 perror("write ");
1404 }
1405 return -1;
1406 }
1407 posn += size;
1408 } while (posn < objsize);
1409
1410 if (map)
1411 munmap(map, objsize);
1412 if (temp_obj)
1413 free(temp_obj);
1414
1415 return 0;
1416 }
1417
1418 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1419 size_t bufsize, size_t *bufposn)
1420 {
1421 char *filename = sha1_file_name(sha1);
1422
1423 int local;
1424 z_stream stream;
1425 unsigned char real_sha1[20];
1426 unsigned char discard[4096];
1427 int ret;
1428 SHA_CTX c;
1429
1430 local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
1431
1432 if (local < 0)
1433 return error("Couldn't open %s\n", filename);
1434
1435 memset(&stream, 0, sizeof(stream));
1436
1437 inflateInit(&stream);
1438
1439 SHA1_Init(&c);
1440
1441 do {
1442 ssize_t size;
1443 if (*bufposn) {
1444 stream.avail_in = *bufposn;
1445 stream.next_in = (unsigned char *) buffer;
1446 do {
1447 stream.next_out = discard;
1448 stream.avail_out = sizeof(discard);
1449 ret = inflate(&stream, Z_SYNC_FLUSH);
1450 SHA1_Update(&c, discard, sizeof(discard) -
1451 stream.avail_out);
1452 } while (stream.avail_in && ret == Z_OK);
1453 write(local, buffer, *bufposn - stream.avail_in);
1454 memmove(buffer, buffer + *bufposn - stream.avail_in,
1455 stream.avail_in);
1456 *bufposn = stream.avail_in;
1457 if (ret != Z_OK)
1458 break;
1459 }
1460 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1461 if (size <= 0) {
1462 close(local);
1463 unlink(filename);
1464 if (!size)
1465 return error("Connection closed?");
1466 perror("Reading from connection");
1467 return -1;
1468 }
1469 *bufposn += size;
1470 } while (1);
1471 inflateEnd(&stream);
1472
1473 close(local);
1474 SHA1_Final(real_sha1, &c);
1475 if (ret != Z_STREAM_END) {
1476 unlink(filename);
1477 return error("File %s corrupted", sha1_to_hex(sha1));
1478 }
1479 if (memcmp(sha1, real_sha1, 20)) {
1480 unlink(filename);
1481 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1482 }
1483
1484 return 0;
1485 }
1486
1487 int has_pack_index(const unsigned char *sha1)
1488 {
1489 struct stat st;
1490 if (stat(sha1_pack_index_name(sha1), &st))
1491 return 0;
1492 return 1;
1493 }
1494
1495 int has_pack_file(const unsigned char *sha1)
1496 {
1497 struct stat st;
1498 if (stat(sha1_pack_name(sha1), &st))
1499 return 0;
1500 return 1;
1501 }
1502
1503 int has_sha1_pack(const unsigned char *sha1)
1504 {
1505 struct pack_entry e;
1506 return find_pack_entry(sha1, &e);
1507 }
1508
1509 int has_sha1_file(const unsigned char *sha1)
1510 {
1511 struct stat st;
1512 struct pack_entry e;
1513
1514 if (find_pack_entry(sha1, &e))
1515 return 1;
1516 return find_sha1_file(sha1, &st) ? 1 : 0;
1517 }
1518
1519 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1520 {
1521 unsigned long size = st->st_size;
1522 void *buf;
1523 int ret;
1524 unsigned char hdr[50];
1525 int hdrlen;
1526
1527 buf = "";
1528 if (size)
1529 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1530 close(fd);
1531 if (buf == MAP_FAILED)
1532 return -1;
1533
1534 if (!type)
1535 type = "blob";
1536 if (write_object)
1537 ret = write_sha1_file(buf, size, type, sha1);
1538 else {
1539 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1540 ret = 0;
1541 }
1542 if (size)
1543 munmap(buf, size);
1544 return ret;
1545 }