[PATCH] Update fsck-cache (take 2)
[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
14 #ifndef O_NOATIME
15 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
16 #define O_NOATIME 01000000
17 #else
18 #define O_NOATIME 0
19 #endif
20 #endif
21
22 static unsigned int sha1_file_open_flag = O_NOATIME;
23
24 static unsigned hexval(char c)
25 {
26 if (c >= '0' && c <= '9')
27 return c - '0';
28 if (c >= 'a' && c <= 'f')
29 return c - 'a' + 10;
30 if (c >= 'A' && c <= 'F')
31 return c - 'A' + 10;
32 return ~0;
33 }
34
35 int get_sha1_hex(const char *hex, unsigned char *sha1)
36 {
37 int i;
38 for (i = 0; i < 20; i++) {
39 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
40 if (val & ~0xff)
41 return -1;
42 *sha1++ = val;
43 hex += 2;
44 }
45 return 0;
46 }
47
48 static int get_sha1_file(const char *path, unsigned char *result)
49 {
50 char buffer[60];
51 int fd = open(path, O_RDONLY);
52 int len;
53
54 if (fd < 0)
55 return -1;
56 len = read(fd, buffer, sizeof(buffer));
57 close(fd);
58 if (len < 40)
59 return -1;
60 return get_sha1_hex(buffer, result);
61 }
62
63 static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir;
64 static void setup_git_env(void)
65 {
66 git_dir = gitenv(GIT_DIR_ENVIRONMENT);
67 if (!git_dir)
68 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
69 git_object_dir = gitenv(DB_ENVIRONMENT);
70 if (!git_object_dir) {
71 git_object_dir = xmalloc(strlen(git_dir) + 9);
72 sprintf(git_object_dir, "%s/objects", git_dir);
73 }
74 git_refs_dir = xmalloc(strlen(git_dir) + 6);
75 sprintf(git_refs_dir, "%s/refs", git_dir);
76 git_index_file = gitenv(INDEX_ENVIRONMENT);
77 if (!git_index_file) {
78 git_index_file = xmalloc(strlen(git_dir) + 7);
79 sprintf(git_index_file, "%s/index", git_dir);
80 }
81 }
82
83 char *get_object_directory(void)
84 {
85 if (!git_object_dir)
86 setup_git_env();
87 return git_object_dir;
88 }
89
90 char *get_refs_directory(void)
91 {
92 if (!git_refs_dir)
93 setup_git_env();
94 return git_refs_dir;
95 }
96
97 char *get_index_file(void)
98 {
99 if (!git_index_file)
100 setup_git_env();
101 return git_index_file;
102 }
103
104 int get_sha1(const char *str, unsigned char *sha1)
105 {
106 static char pathname[PATH_MAX];
107 static const char *prefix[] = {
108 "",
109 "refs",
110 "refs/tags",
111 "refs/heads",
112 "refs/snap",
113 NULL
114 };
115 const char **p;
116
117 if (!get_sha1_hex(str, sha1))
118 return 0;
119
120 if (!git_dir)
121 setup_git_env();
122 for (p = prefix; *p; p++) {
123 snprintf(pathname, sizeof(pathname), "%s/%s/%s",
124 git_dir, *p, str);
125 if (!get_sha1_file(pathname, sha1))
126 return 0;
127 }
128
129 return -1;
130 }
131
132 char * sha1_to_hex(const unsigned char *sha1)
133 {
134 static char buffer[50];
135 static const char hex[] = "0123456789abcdef";
136 char *buf = buffer;
137 int i;
138
139 for (i = 0; i < 20; i++) {
140 unsigned int val = *sha1++;
141 *buf++ = hex[val >> 4];
142 *buf++ = hex[val & 0xf];
143 }
144 return buffer;
145 }
146
147 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
148 {
149 int i;
150 for (i = 0; i < 20; i++) {
151 static char hex[] = "0123456789abcdef";
152 unsigned int val = sha1[i];
153 char *pos = pathbuf + i*2 + (i > 0);
154 *pos++ = hex[val >> 4];
155 *pos = hex[val & 0xf];
156 }
157 }
158
159 /*
160 * NOTE! This returns a statically allocated buffer, so you have to be
161 * careful about using it. Do a "strdup()" if you need to save the
162 * filename.
163 *
164 * Also note that this returns the location for creating. Reading
165 * SHA1 file can happen from any alternate directory listed in the
166 * DB_ENVIRONMENT environment variable if it is not found in
167 * the primary object database.
168 */
169 char *sha1_file_name(const unsigned char *sha1)
170 {
171 static char *name, *base;
172
173 if (!base) {
174 const char *sha1_file_directory = get_object_directory();
175 int len = strlen(sha1_file_directory);
176 base = xmalloc(len + 60);
177 memcpy(base, sha1_file_directory, len);
178 memset(base+len, 0, 60);
179 base[len] = '/';
180 base[len+3] = '/';
181 name = base + len + 1;
182 }
183 fill_sha1_path(name, sha1);
184 return base;
185 }
186
187 struct alternate_object_database *alt_odb;
188
189 /*
190 * Prepare alternate object database registry.
191 * alt_odb points at an array of struct alternate_object_database.
192 * This array is terminated with an element that has both its base
193 * and name set to NULL. alt_odb[n] comes from n'th non-empty
194 * element from colon separated ALTERNATE_DB_ENVIRONMENT environment
195 * variable, and its base points at a statically allocated buffer
196 * that contains "/the/directory/corresponding/to/.git/objects/...",
197 * while its name points just after the slash at the end of
198 * ".git/objects/" in the example above, and has enough space to hold
199 * 40-byte hex SHA1, an extra slash for the first level indirection,
200 * and the terminating NUL.
201 * This function allocates the alt_odb array and all the strings
202 * pointed by base fields of the array elements with one xmalloc();
203 * the string pool immediately follows the array.
204 */
205 void prepare_alt_odb(void)
206 {
207 int pass, totlen, i;
208 const char *cp, *last;
209 char *op = NULL;
210 const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
211
212 if (alt_odb)
213 return;
214 /* The first pass counts how large an area to allocate to
215 * hold the entire alt_odb structure, including array of
216 * structs and path buffers for them. The second pass fills
217 * the structure and prepares the path buffers for use by
218 * fill_sha1_path().
219 */
220 for (totlen = pass = 0; pass < 2; pass++) {
221 last = alt;
222 i = 0;
223 do {
224 cp = strchr(last, ':') ? : last + strlen(last);
225 if (last != cp) {
226 /* 43 = 40-byte + 2 '/' + terminating NUL */
227 int pfxlen = cp - last;
228 int entlen = pfxlen + 43;
229 if (pass == 0)
230 totlen += entlen;
231 else {
232 alt_odb[i].base = op;
233 alt_odb[i].name = op + pfxlen + 1;
234 memcpy(op, last, pfxlen);
235 op[pfxlen] = op[pfxlen + 3] = '/';
236 op[entlen-1] = 0;
237 op += entlen;
238 }
239 i++;
240 }
241 while (*cp && *cp == ':')
242 cp++;
243 last = cp;
244 } while (*cp);
245 if (pass)
246 break;
247 alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
248 alt_odb[i].base = alt_odb[i].name = NULL;
249 op = (char*)(&alt_odb[i+1]);
250 }
251 }
252
253 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
254 {
255 int i;
256 char *name = sha1_file_name(sha1);
257
258 if (!stat(name, st))
259 return name;
260 prepare_alt_odb();
261 for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
262 fill_sha1_path(name, sha1);
263 if (!stat(alt_odb[i].base, st))
264 return alt_odb[i].base;
265 }
266 return NULL;
267 }
268
269 #define PACK_MAX_SZ (1<<26)
270 static int pack_used_ctr;
271 static unsigned long pack_mapped;
272 struct packed_git *packed_git;
273
274 struct pack_entry {
275 unsigned int offset;
276 unsigned char sha1[20];
277 struct packed_git *p;
278 };
279
280 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
281 void **idx_map_)
282 {
283 void *idx_map;
284 unsigned int *index;
285 unsigned long idx_size;
286 int nr, i;
287 int fd = open(path, O_RDONLY);
288 struct stat st;
289 if (fd < 0)
290 return -1;
291 if (fstat(fd, &st)) {
292 close(fd);
293 return -1;
294 }
295 idx_size = st.st_size;
296 idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
297 close(fd);
298 if (idx_map == MAP_FAILED)
299 return -1;
300
301 index = idx_map;
302
303 /* check index map */
304 if (idx_size < 4*256 + 20)
305 return error("index file too small");
306 nr = 0;
307 for (i = 0; i < 256; i++) {
308 unsigned int n = ntohl(index[i]);
309 if (n < nr)
310 return error("non-monotonic index");
311 nr = n;
312 }
313
314 /*
315 * Total size:
316 * - 256 index entries 4 bytes each
317 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
318 * - 20-byte SHA1 of the packfile
319 * - 20-byte SHA1 file checksum
320 */
321 if (idx_size != 4*256 + nr * 24 + 20 + 20)
322 return error("wrong index file size");
323
324 *idx_map_ = idx_map;
325 *idx_size_ = idx_size;
326 return 0;
327 }
328
329 static void unuse_one_packed_git(void)
330 {
331 /* NOTYET */
332 }
333
334 static int use_packed_git(struct packed_git *p)
335 {
336 if (!p->pack_base) {
337 int fd;
338 struct stat st;
339 void *map;
340
341 pack_mapped += p->pack_size;
342 while (PACK_MAX_SZ < pack_mapped)
343 unuse_one_packed_git();
344 fd = open(p->pack_name, O_RDONLY);
345 if (fd < 0)
346 return -1;
347 if (fstat(fd, &st)) {
348 close(fd);
349 return -1;
350 }
351 if (st.st_size != p->pack_size)
352 return -1;
353 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
354 close(fd);
355 if (map == MAP_FAILED)
356 return -1;
357 p->pack_base = map;
358 }
359 p->pack_last_used = pack_used_ctr++;
360 return 0;
361 }
362
363 static struct packed_git *add_packed_git(char *path, int path_len)
364 {
365 struct stat st;
366 struct packed_git *p;
367 unsigned long idx_size;
368 void *idx_map;
369
370 if (check_packed_git_idx(path, &idx_size, &idx_map))
371 return NULL;
372
373 /* do we have a corresponding .pack file? */
374 strcpy(path + path_len - 4, ".pack");
375 if (stat(path, &st) || !S_ISREG(st.st_mode)) {
376 munmap(idx_map, idx_size);
377 return NULL;
378 }
379 /* ok, it looks sane as far as we can check without
380 * actually mapping the pack file.
381 */
382 p = xmalloc(sizeof(*p) + path_len + 2);
383 strcpy(p->pack_name, path);
384 p->index_size = idx_size;
385 p->pack_size = st.st_size;
386 p->index_base = idx_map;
387 p->next = NULL;
388 p->pack_last_used = 0;
389 return p;
390 }
391
392 static void prepare_packed_git_one(char *objdir)
393 {
394 char path[PATH_MAX];
395 int len;
396 DIR *dir;
397 struct dirent *de;
398
399 sprintf(path, "%s/pack", objdir);
400 len = strlen(path);
401 dir = opendir(path);
402 if (!dir)
403 return;
404 path[len++] = '/';
405 while ((de = readdir(dir)) != NULL) {
406 int namelen = strlen(de->d_name);
407 struct packed_git *p;
408
409 if (strcmp(de->d_name + namelen - 4, ".idx"))
410 continue;
411
412 /* we have .idx. Is it a file we can map? */
413 strcpy(path + len, de->d_name);
414 p = add_packed_git(path, len + namelen);
415 if (!p)
416 continue;
417 p->next = packed_git;
418 packed_git = p;
419 }
420 }
421
422 void prepare_packed_git(void)
423 {
424 int i;
425 static int run_once = 0;
426
427 if (run_once++)
428 return;
429
430 prepare_packed_git_one(get_object_directory());
431 prepare_alt_odb();
432 for (i = 0; alt_odb[i].base != NULL; i++) {
433 alt_odb[i].name[0] = 0;
434 prepare_packed_git_one(alt_odb[i].base);
435 }
436 }
437
438 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
439 {
440 char header[100];
441 unsigned char real_sha1[20];
442 SHA_CTX c;
443
444 SHA1_Init(&c);
445 SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
446 SHA1_Update(&c, map, size);
447 SHA1_Final(real_sha1, &c);
448 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
449 }
450
451 static void *map_sha1_file_internal(const unsigned char *sha1,
452 unsigned long *size,
453 int say_error)
454 {
455 struct stat st;
456 void *map;
457 int fd;
458 char *filename = find_sha1_file(sha1, &st);
459
460 if (!filename) {
461 if (say_error)
462 error("cannot map sha1 file %s", sha1_to_hex(sha1));
463 return NULL;
464 }
465
466 fd = open(filename, O_RDONLY | sha1_file_open_flag);
467 if (fd < 0) {
468 /* See if it works without O_NOATIME */
469 switch (sha1_file_open_flag) {
470 default:
471 fd = open(filename, O_RDONLY);
472 if (fd >= 0)
473 break;
474 /* Fallthrough */
475 case 0:
476 if (say_error)
477 perror(filename);
478 return NULL;
479 }
480
481 /* If it failed once, it will probably fail again.
482 * Stop using O_NOATIME
483 */
484 sha1_file_open_flag = 0;
485 }
486 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
487 close(fd);
488 if (-1 == (int)(long)map)
489 return NULL;
490 *size = st.st_size;
491 return map;
492 }
493
494 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
495 {
496 return map_sha1_file_internal(sha1, size, 1);
497 }
498
499 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
500 {
501 /* Get the data stream */
502 memset(stream, 0, sizeof(*stream));
503 stream->next_in = map;
504 stream->avail_in = mapsize;
505 stream->next_out = buffer;
506 stream->avail_out = size;
507
508 inflateInit(stream);
509 return inflate(stream, 0);
510 }
511
512 void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
513 {
514 int bytes = strlen(buffer) + 1;
515 unsigned char *buf = xmalloc(1+size);
516
517 memcpy(buf, buffer + bytes, stream->total_out - bytes);
518 bytes = stream->total_out - bytes;
519 if (bytes < size) {
520 stream->next_out = buf + bytes;
521 stream->avail_out = size - bytes;
522 while (inflate(stream, Z_FINISH) == Z_OK)
523 /* nothing */;
524 }
525 buf[size] = 0;
526 inflateEnd(stream);
527 return buf;
528 }
529
530 /*
531 * We used to just use "sscanf()", but that's actually way
532 * too permissive for what we want to check. So do an anal
533 * object header parse by hand.
534 */
535 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
536 {
537 int i;
538 unsigned long size;
539
540 /*
541 * The type can be at most ten bytes (including the
542 * terminating '\0' that we add), and is followed by
543 * a space.
544 */
545 i = 10;
546 for (;;) {
547 char c = *hdr++;
548 if (c == ' ')
549 break;
550 if (!--i)
551 return -1;
552 *type++ = c;
553 }
554 *type = 0;
555
556 /*
557 * The length must follow immediately, and be in canonical
558 * decimal format (ie "010" is not valid).
559 */
560 size = *hdr++ - '0';
561 if (size > 9)
562 return -1;
563 if (size) {
564 for (;;) {
565 unsigned long c = *hdr - '0';
566 if (c > 9)
567 break;
568 hdr++;
569 size = size * 10 + c;
570 }
571 }
572 *sizep = size;
573
574 /*
575 * The length must be followed by a zero byte
576 */
577 return *hdr ? -1 : 0;
578 }
579
580 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
581 {
582 int ret;
583 z_stream stream;
584 char hdr[8192];
585
586 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
587 if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
588 return NULL;
589
590 return unpack_sha1_rest(&stream, hdr, *size);
591 }
592
593 static int packed_delta_info(unsigned char *base_sha1,
594 unsigned long delta_size,
595 unsigned long left,
596 char *type,
597 unsigned long *sizep)
598 {
599 unsigned char *data;
600 unsigned char delta_head[64];
601 int i;
602 unsigned char cmd;
603 unsigned long data_size, result_size, base_size, verify_base_size;
604 z_stream stream;
605 int st;
606
607 if (left < 20)
608 die("truncated pack file");
609 if (sha1_object_info(base_sha1, type, &base_size))
610 die("cannot get info for delta-pack base");
611
612 data = base_sha1 + 20;
613 data_size = left - 20;
614
615 memset(&stream, 0, sizeof(stream));
616
617 stream.next_in = data;
618 stream.avail_in = data_size;
619 stream.next_out = delta_head;
620 stream.avail_out = sizeof(delta_head);
621
622 inflateInit(&stream);
623 st = inflate(&stream, Z_FINISH);
624 inflateEnd(&stream);
625 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head))
626 die("delta data unpack-initial failed");
627
628 /* Examine the initial part of the delta to figure out
629 * the result size. Verify the base size while we are at it.
630 */
631 data = delta_head;
632 verify_base_size = i = 0;
633 cmd = *data++;
634 while (cmd) {
635 if (cmd & 1)
636 verify_base_size |= *data++ << i;
637 i += 8;
638 cmd >>= 1;
639 }
640
641 /* Read the result size */
642 result_size = i = 0;
643 cmd = *data++;
644 while (cmd) {
645 if (cmd & 1)
646 result_size |= *data++ << i;
647 i += 8;
648 cmd >>= 1;
649 }
650 if (verify_base_size != base_size)
651 die("delta base size mismatch");
652
653 *sizep = result_size;
654 return 0;
655 }
656
657 static int packed_object_info(struct pack_entry *entry,
658 char *type, unsigned long *sizep)
659 {
660 struct packed_git *p = entry->p;
661 unsigned long offset, size, left;
662 unsigned char *pack;
663
664 offset = entry->offset;
665 if (p->pack_size - 5 < offset)
666 die("object offset outside of pack file");
667
668 if (use_packed_git(p))
669 die("cannot map packed file");
670
671 pack = p->pack_base + offset;
672 size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4];
673 left = p->pack_size - offset - 5;
674 switch (*pack) {
675 case 'D':
676 return packed_delta_info(pack+5, size, left, type, sizep);
677 break;
678 case 'C':
679 strcpy(type, "commit");
680 break;
681 case 'T':
682 strcpy(type, "tree");
683 break;
684 case 'B':
685 strcpy(type, "blob");
686 break;
687 case 'G':
688 strcpy(type, "tag");
689 break;
690 default:
691 die("corrupted pack file");
692 }
693 *sizep = size;
694 return 0;
695 }
696
697 /* forward declaration for a mutually recursive function */
698 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
699
700 static void *unpack_delta_entry(unsigned char *base_sha1,
701 unsigned long delta_size,
702 unsigned long left,
703 char *type,
704 unsigned long *sizep)
705 {
706 void *data, *delta_data, *result, *base;
707 unsigned long data_size, result_size, base_size;
708 z_stream stream;
709 int st;
710
711 if (left < 20)
712 die("truncated pack file");
713 data = base_sha1 + 20;
714 data_size = left - 20;
715 delta_data = xmalloc(delta_size);
716
717 memset(&stream, 0, sizeof(stream));
718
719 stream.next_in = data;
720 stream.avail_in = data_size;
721 stream.next_out = delta_data;
722 stream.avail_out = delta_size;
723
724 inflateInit(&stream);
725 st = inflate(&stream, Z_FINISH);
726 inflateEnd(&stream);
727 if ((st != Z_STREAM_END) || stream.total_out != delta_size)
728 die("delta data unpack failed");
729
730 /* This may recursively unpack the base, which is what we want */
731 base = read_sha1_file(base_sha1, type, &base_size);
732 if (!base)
733 die("failed to read delta-pack base object %s",
734 sha1_to_hex(base_sha1));
735 result = patch_delta(base, base_size,
736 delta_data, delta_size,
737 &result_size);
738 if (!result)
739 die("failed to apply delta");
740 free(delta_data);
741 free(base);
742 *sizep = result_size;
743 return result;
744 }
745
746 static void *unpack_non_delta_entry(unsigned char *data,
747 unsigned long size,
748 unsigned long left)
749 {
750 int st;
751 z_stream stream;
752 char *buffer;
753
754 buffer = xmalloc(size + 1);
755 buffer[size] = 0;
756 memset(&stream, 0, sizeof(stream));
757 stream.next_in = data;
758 stream.avail_in = left;
759 stream.next_out = buffer;
760 stream.avail_out = size;
761
762 inflateInit(&stream);
763 st = inflate(&stream, Z_FINISH);
764 inflateEnd(&stream);
765 if ((st != Z_STREAM_END) || stream.total_out != size) {
766 free(buffer);
767 return NULL;
768 }
769
770 return buffer;
771 }
772
773 static void *unpack_entry(struct pack_entry *entry,
774 char *type, unsigned long *sizep)
775 {
776 struct packed_git *p = entry->p;
777 unsigned long offset, size, left;
778 unsigned char *pack;
779
780 offset = entry->offset;
781 if (p->pack_size - 5 < offset)
782 die("object offset outside of pack file");
783
784 if (use_packed_git(p))
785 die("cannot map packed file");
786
787 pack = p->pack_base + offset;
788 size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4];
789 left = p->pack_size - offset - 5;
790 switch (*pack) {
791 case 'D':
792 return unpack_delta_entry(pack+5, size, left, type, sizep);
793 case 'C':
794 strcpy(type, "commit");
795 break;
796 case 'T':
797 strcpy(type, "tree");
798 break;
799 case 'B':
800 strcpy(type, "blob");
801 break;
802 case 'G':
803 strcpy(type, "tag");
804 break;
805 default:
806 die("corrupted pack file");
807 }
808 *sizep = size;
809 return unpack_non_delta_entry(pack+5, size, left);
810 }
811
812 int num_packed_objects(const struct packed_git *p)
813 {
814 /* See check_packed_git_idx and pack-objects.c */
815 return (p->index_size - 20 - 20 - 4*256) / 24;
816 }
817
818 int nth_packed_object_sha1(const struct packed_git *p, int n,
819 unsigned char* sha1)
820 {
821 void *index = p->index_base + 256;
822 if (n < 0 || num_packed_objects(p) <= n)
823 return -1;
824 memcpy(sha1, (index + 24 * n + 4), 20);
825 return 0;
826 }
827
828 static int find_pack_entry_1(const unsigned char *sha1,
829 struct pack_entry *e, struct packed_git *p)
830 {
831 int *level1_ofs = p->index_base;
832 int hi = ntohl(level1_ofs[*sha1]);
833 int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
834 void *index = p->index_base + 256;
835
836 do {
837 int mi = (lo + hi) / 2;
838 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
839 if (!cmp) {
840 e->offset = ntohl(*((int*)(index + 24 * mi)));
841 memcpy(e->sha1, sha1, 20);
842 e->p = p;
843 return 1;
844 }
845 if (cmp > 0)
846 hi = mi;
847 else
848 lo = mi+1;
849 } while (lo < hi);
850 return 0;
851 }
852
853 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
854 {
855 struct packed_git *p;
856 prepare_packed_git();
857
858 for (p = packed_git; p; p = p->next) {
859 if (find_pack_entry_1(sha1, e, p))
860 return 1;
861 }
862 return 0;
863 }
864
865 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
866 {
867 int status;
868 unsigned long mapsize, size;
869 void *map;
870 z_stream stream;
871 char hdr[128];
872
873 map = map_sha1_file_internal(sha1, &mapsize, 0);
874 if (!map) {
875 struct pack_entry e;
876
877 if (!find_pack_entry(sha1, &e))
878 return error("unable to find %s", sha1_to_hex(sha1));
879 if (!packed_object_info(&e, type, sizep))
880 return 0;
881 /* sheesh */
882 map = unpack_entry(&e, type, sizep);
883 free(map);
884 return (map == NULL) ? 0 : -1;
885 }
886 if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
887 status = error("unable to unpack %s header",
888 sha1_to_hex(sha1));
889 if (parse_sha1_header(hdr, type, &size) < 0)
890 status = error("unable to parse %s header", sha1_to_hex(sha1));
891 else {
892 status = 0;
893 *sizep = size;
894 }
895 inflateEnd(&stream);
896 munmap(map, mapsize);
897 return status;
898 }
899
900 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
901 {
902 struct pack_entry e;
903
904 if (!find_pack_entry(sha1, &e)) {
905 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
906 return NULL;
907 }
908 return unpack_entry(&e, type, size);
909 }
910
911 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
912 {
913 unsigned long mapsize;
914 void *map, *buf;
915
916 map = map_sha1_file_internal(sha1, &mapsize, 0);
917 if (map) {
918 buf = unpack_sha1_file(map, mapsize, type, size);
919 munmap(map, mapsize);
920 return buf;
921 }
922 return read_packed_sha1(sha1, type, size);
923 }
924
925 void *read_object_with_reference(const unsigned char *sha1,
926 const char *required_type,
927 unsigned long *size,
928 unsigned char *actual_sha1_return)
929 {
930 char type[20];
931 void *buffer;
932 unsigned long isize;
933 unsigned char actual_sha1[20];
934
935 memcpy(actual_sha1, sha1, 20);
936 while (1) {
937 int ref_length = -1;
938 const char *ref_type = NULL;
939
940 buffer = read_sha1_file(actual_sha1, type, &isize);
941 if (!buffer)
942 return NULL;
943 if (!strcmp(type, required_type)) {
944 *size = isize;
945 if (actual_sha1_return)
946 memcpy(actual_sha1_return, actual_sha1, 20);
947 return buffer;
948 }
949 /* Handle references */
950 else if (!strcmp(type, "commit"))
951 ref_type = "tree ";
952 else if (!strcmp(type, "tag"))
953 ref_type = "object ";
954 else {
955 free(buffer);
956 return NULL;
957 }
958 ref_length = strlen(ref_type);
959
960 if (memcmp(buffer, ref_type, ref_length) ||
961 get_sha1_hex(buffer + ref_length, actual_sha1)) {
962 free(buffer);
963 return NULL;
964 }
965 /* Now we have the ID of the referred-to object in
966 * actual_sha1. Check again. */
967 }
968 }
969
970 static char *write_sha1_file_prepare(void *buf,
971 unsigned long len,
972 const char *type,
973 unsigned char *sha1,
974 unsigned char *hdr,
975 int *hdrlen)
976 {
977 SHA_CTX c;
978
979 /* Generate the header */
980 *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
981
982 /* Sha1.. */
983 SHA1_Init(&c);
984 SHA1_Update(&c, hdr, *hdrlen);
985 SHA1_Update(&c, buf, len);
986 SHA1_Final(sha1, &c);
987
988 return sha1_file_name(sha1);
989 }
990
991 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
992 {
993 int size;
994 unsigned char *compressed;
995 z_stream stream;
996 unsigned char sha1[20];
997 char *filename;
998 static char tmpfile[PATH_MAX];
999 unsigned char hdr[50];
1000 int fd, hdrlen, ret;
1001
1002 /* Normally if we have it in the pack then we do not bother writing
1003 * it out into .git/objects/??/?{38} file.
1004 */
1005 filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1006 if (returnsha1)
1007 memcpy(returnsha1, sha1, 20);
1008 if (has_sha1_file(sha1))
1009 return 0;
1010 fd = open(filename, O_RDONLY);
1011 if (fd >= 0) {
1012 /*
1013 * FIXME!!! We might do collision checking here, but we'd
1014 * need to uncompress the old file and check it. Later.
1015 */
1016 close(fd);
1017 return 0;
1018 }
1019
1020 if (errno != ENOENT) {
1021 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1022 return -1;
1023 }
1024
1025 snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1026
1027 fd = mkstemp(tmpfile);
1028 if (fd < 0) {
1029 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1030 return -1;
1031 }
1032
1033 /* Set it up */
1034 memset(&stream, 0, sizeof(stream));
1035 deflateInit(&stream, Z_BEST_COMPRESSION);
1036 size = deflateBound(&stream, len+hdrlen);
1037 compressed = xmalloc(size);
1038
1039 /* Compress it */
1040 stream.next_out = compressed;
1041 stream.avail_out = size;
1042
1043 /* First header.. */
1044 stream.next_in = hdr;
1045 stream.avail_in = hdrlen;
1046 while (deflate(&stream, 0) == Z_OK)
1047 /* nothing */;
1048
1049 /* Then the data itself.. */
1050 stream.next_in = buf;
1051 stream.avail_in = len;
1052 while (deflate(&stream, Z_FINISH) == Z_OK)
1053 /* nothing */;
1054 deflateEnd(&stream);
1055 size = stream.total_out;
1056
1057 if (write(fd, compressed, size) != size)
1058 die("unable to write file");
1059 fchmod(fd, 0444);
1060 close(fd);
1061 free(compressed);
1062
1063 ret = link(tmpfile, filename);
1064 if (ret < 0) {
1065 ret = errno;
1066
1067 /*
1068 * Coda hack - coda doesn't like cross-directory links,
1069 * so we fall back to a rename, which will mean that it
1070 * won't be able to check collisions, but that's not a
1071 * big deal.
1072 *
1073 * When this succeeds, we just return 0. We have nothing
1074 * left to unlink.
1075 */
1076 if (ret == EXDEV && !rename(tmpfile, filename))
1077 return 0;
1078 }
1079 unlink(tmpfile);
1080 if (ret) {
1081 if (ret != EEXIST) {
1082 fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1083 return -1;
1084 }
1085 /* FIXME!!! Collision check here ? */
1086 }
1087
1088 return 0;
1089 }
1090
1091 int write_sha1_from_fd(const unsigned char *sha1, int fd)
1092 {
1093 char *filename = sha1_file_name(sha1);
1094
1095 int local;
1096 z_stream stream;
1097 unsigned char real_sha1[20];
1098 unsigned char buf[4096];
1099 unsigned char discard[4096];
1100 int ret;
1101 SHA_CTX c;
1102
1103 local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
1104
1105 if (local < 0)
1106 return error("Couldn't open %s\n", filename);
1107
1108 memset(&stream, 0, sizeof(stream));
1109
1110 inflateInit(&stream);
1111
1112 SHA1_Init(&c);
1113
1114 do {
1115 ssize_t size;
1116 size = read(fd, buf, 4096);
1117 if (size <= 0) {
1118 close(local);
1119 unlink(filename);
1120 if (!size)
1121 return error("Connection closed?");
1122 perror("Reading from connection");
1123 return -1;
1124 }
1125 write(local, buf, size);
1126 stream.avail_in = size;
1127 stream.next_in = buf;
1128 do {
1129 stream.next_out = discard;
1130 stream.avail_out = sizeof(discard);
1131 ret = inflate(&stream, Z_SYNC_FLUSH);
1132 SHA1_Update(&c, discard, sizeof(discard) -
1133 stream.avail_out);
1134 } while (stream.avail_in && ret == Z_OK);
1135
1136 } while (ret == Z_OK);
1137 inflateEnd(&stream);
1138
1139 close(local);
1140 SHA1_Final(real_sha1, &c);
1141 if (ret != Z_STREAM_END) {
1142 unlink(filename);
1143 return error("File %s corrupted", sha1_to_hex(sha1));
1144 }
1145 if (memcmp(sha1, real_sha1, 20)) {
1146 unlink(filename);
1147 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1148 }
1149
1150 return 0;
1151 }
1152
1153 int has_sha1_file(const unsigned char *sha1)
1154 {
1155 struct stat st;
1156 struct pack_entry e;
1157
1158 if (find_sha1_file(sha1, &st))
1159 return 1;
1160 return find_pack_entry(sha1, &e);
1161 }
1162
1163 int index_fd(unsigned char *sha1, int fd, struct stat *st)
1164 {
1165 unsigned long size = st->st_size;
1166 void *buf;
1167 int ret;
1168
1169 buf = "";
1170 if (size)
1171 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1172 close(fd);
1173 if ((int)(long)buf == -1)
1174 return -1;
1175
1176 ret = write_sha1_file(buf, size, "blob", sha1);
1177 if (size)
1178 munmap(buf, size);
1179 return ret;
1180 }