f6cf180bd485bc7be78e2cd969c8cd3139f6ad6d
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"
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
23 static unsigned int sha1_file_open_flag = O_NOATIME;
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 }
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 }
49 static int get_sha1_file(const char *path, unsigned char *result)
50 {
51 char buffer[60];
52 int fd = open(path, O_RDONLY);
53 int len;
55 if (fd < 0)
56 return -1;
57 len = read(fd, buffer, sizeof(buffer));
58 close(fd);
59 if (len < 40)
60 return -1;
61 return get_sha1_hex(buffer, result);
62 }
64 static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir;
65 static void setup_git_env(void)
66 {
67 git_dir = gitenv(GIT_DIR_ENVIRONMENT);
68 if (!git_dir)
69 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
70 git_object_dir = gitenv(DB_ENVIRONMENT);
71 if (!git_object_dir) {
72 git_object_dir = xmalloc(strlen(git_dir) + 9);
73 sprintf(git_object_dir, "%s/objects", git_dir);
74 }
75 git_refs_dir = xmalloc(strlen(git_dir) + 6);
76 sprintf(git_refs_dir, "%s/refs", git_dir);
77 git_index_file = gitenv(INDEX_ENVIRONMENT);
78 if (!git_index_file) {
79 git_index_file = xmalloc(strlen(git_dir) + 7);
80 sprintf(git_index_file, "%s/index", git_dir);
81 }
82 }
84 char *get_object_directory(void)
85 {
86 if (!git_object_dir)
87 setup_git_env();
88 return git_object_dir;
89 }
91 char *get_refs_directory(void)
92 {
93 if (!git_refs_dir)
94 setup_git_env();
95 return git_refs_dir;
96 }
98 char *get_index_file(void)
99 {
100 if (!git_index_file)
101 setup_git_env();
102 return git_index_file;
103 }
105 int get_sha1(const char *str, unsigned char *sha1)
106 {
107 static char pathname[PATH_MAX];
108 static const char *prefix[] = {
109 "",
110 "refs",
111 "refs/tags",
112 "refs/heads",
113 "refs/snap",
114 NULL
115 };
116 const char **p;
118 if (!get_sha1_hex(str, sha1))
119 return 0;
121 if (!git_dir)
122 setup_git_env();
123 for (p = prefix; *p; p++) {
124 snprintf(pathname, sizeof(pathname), "%s/%s/%s",
125 git_dir, *p, str);
126 if (!get_sha1_file(pathname, sha1))
127 return 0;
128 }
130 return -1;
131 }
133 char * sha1_to_hex(const unsigned char *sha1)
134 {
135 static char buffer[50];
136 static const char hex[] = "0123456789abcdef";
137 char *buf = buffer;
138 int i;
140 for (i = 0; i < 20; i++) {
141 unsigned int val = *sha1++;
142 *buf++ = hex[val >> 4];
143 *buf++ = hex[val & 0xf];
144 }
145 return buffer;
146 }
148 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
149 {
150 int i;
151 for (i = 0; i < 20; i++) {
152 static char hex[] = "0123456789abcdef";
153 unsigned int val = sha1[i];
154 char *pos = pathbuf + i*2 + (i > 0);
155 *pos++ = hex[val >> 4];
156 *pos = hex[val & 0xf];
157 }
158 }
160 /*
161 * NOTE! This returns a statically allocated buffer, so you have to be
162 * careful about using it. Do a "strdup()" if you need to save the
163 * filename.
164 *
165 * Also note that this returns the location for creating. Reading
166 * SHA1 file can happen from any alternate directory listed in the
167 * DB_ENVIRONMENT environment variable if it is not found in
168 * the primary object database.
169 */
170 char *sha1_file_name(const unsigned char *sha1)
171 {
172 static char *name, *base;
174 if (!base) {
175 const char *sha1_file_directory = get_object_directory();
176 int len = strlen(sha1_file_directory);
177 base = xmalloc(len + 60);
178 memcpy(base, sha1_file_directory, len);
179 memset(base+len, 0, 60);
180 base[len] = '/';
181 base[len+3] = '/';
182 name = base + len + 1;
183 }
184 fill_sha1_path(name, sha1);
185 return base;
186 }
188 struct alternate_object_database *alt_odb;
190 /*
191 * Prepare alternate object database registry.
192 * alt_odb points at an array of struct alternate_object_database.
193 * This array is terminated with an element that has both its base
194 * and name set to NULL. alt_odb[n] comes from n'th non-empty
195 * element from colon separated ALTERNATE_DB_ENVIRONMENT environment
196 * variable, and its base points at a statically allocated buffer
197 * that contains "/the/directory/corresponding/to/.git/objects/...",
198 * while its name points just after the slash at the end of
199 * ".git/objects/" in the example above, and has enough space to hold
200 * 40-byte hex SHA1, an extra slash for the first level indirection,
201 * and the terminating NUL.
202 * This function allocates the alt_odb array and all the strings
203 * pointed by base fields of the array elements with one xmalloc();
204 * the string pool immediately follows the array.
205 */
206 void prepare_alt_odb(void)
207 {
208 int pass, totlen, i;
209 const char *cp, *last;
210 char *op = NULL;
211 const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
213 if (alt_odb)
214 return;
215 /* The first pass counts how large an area to allocate to
216 * hold the entire alt_odb structure, including array of
217 * structs and path buffers for them. The second pass fills
218 * the structure and prepares the path buffers for use by
219 * fill_sha1_path().
220 */
221 for (totlen = pass = 0; pass < 2; pass++) {
222 last = alt;
223 i = 0;
224 do {
225 cp = strchr(last, ':') ? : last + strlen(last);
226 if (last != cp) {
227 /* 43 = 40-byte + 2 '/' + terminating NUL */
228 int pfxlen = cp - last;
229 int entlen = pfxlen + 43;
230 if (pass == 0)
231 totlen += entlen;
232 else {
233 alt_odb[i].base = op;
234 alt_odb[i].name = op + pfxlen + 1;
235 memcpy(op, last, pfxlen);
236 op[pfxlen] = op[pfxlen + 3] = '/';
237 op[entlen-1] = 0;
238 op += entlen;
239 }
240 i++;
241 }
242 while (*cp && *cp == ':')
243 cp++;
244 last = cp;
245 } while (*cp);
246 if (pass)
247 break;
248 alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
249 alt_odb[i].base = alt_odb[i].name = NULL;
250 op = (char*)(&alt_odb[i+1]);
251 }
252 }
254 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
255 {
256 int i;
257 char *name = sha1_file_name(sha1);
259 if (!stat(name, st))
260 return name;
261 prepare_alt_odb();
262 for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
263 fill_sha1_path(name, sha1);
264 if (!stat(alt_odb[i].base, st))
265 return alt_odb[i].base;
266 }
267 return NULL;
268 }
270 #define PACK_MAX_SZ (1<<26)
271 static int pack_used_ctr;
272 static unsigned long pack_mapped;
273 struct packed_git *packed_git;
275 struct pack_entry {
276 unsigned int offset;
277 unsigned char sha1[20];
278 struct packed_git *p;
279 };
281 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
282 void **idx_map_)
283 {
284 void *idx_map;
285 unsigned int *index;
286 unsigned long idx_size;
287 int nr, i;
288 int fd = open(path, O_RDONLY);
289 struct stat st;
290 if (fd < 0)
291 return -1;
292 if (fstat(fd, &st)) {
293 close(fd);
294 return -1;
295 }
296 idx_size = st.st_size;
297 idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
298 close(fd);
299 if (idx_map == MAP_FAILED)
300 return -1;
302 index = idx_map;
304 /* check index map */
305 if (idx_size < 4*256 + 20)
306 return error("index file too small");
307 nr = 0;
308 for (i = 0; i < 256; i++) {
309 unsigned int n = ntohl(index[i]);
310 if (n < nr)
311 return error("non-monotonic index");
312 nr = n;
313 }
315 /*
316 * Total size:
317 * - 256 index entries 4 bytes each
318 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
319 * - 20-byte SHA1 of the packfile
320 * - 20-byte SHA1 file checksum
321 */
322 if (idx_size != 4*256 + nr * 24 + 20 + 20)
323 return error("wrong index file size");
325 *idx_map_ = idx_map;
326 *idx_size_ = idx_size;
327 return 0;
328 }
330 static void unuse_one_packed_git(void)
331 {
332 /* NOTYET */
333 }
335 static int use_packed_git(struct packed_git *p)
336 {
337 if (!p->pack_base) {
338 int fd;
339 struct stat st;
340 void *map;
342 pack_mapped += p->pack_size;
343 while (PACK_MAX_SZ < pack_mapped)
344 unuse_one_packed_git();
345 fd = open(p->pack_name, O_RDONLY);
346 if (fd < 0)
347 return -1;
348 if (fstat(fd, &st)) {
349 close(fd);
350 return -1;
351 }
352 if (st.st_size != p->pack_size)
353 return -1;
354 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
355 close(fd);
356 if (map == MAP_FAILED)
357 return -1;
358 p->pack_base = map;
359 }
360 p->pack_last_used = pack_used_ctr++;
361 return 0;
362 }
364 static struct packed_git *add_packed_git(char *path, int path_len)
365 {
366 struct stat st;
367 struct packed_git *p;
368 unsigned long idx_size;
369 void *idx_map;
371 if (check_packed_git_idx(path, &idx_size, &idx_map))
372 return NULL;
374 /* do we have a corresponding .pack file? */
375 strcpy(path + path_len - 4, ".pack");
376 if (stat(path, &st) || !S_ISREG(st.st_mode)) {
377 munmap(idx_map, idx_size);
378 return NULL;
379 }
380 /* ok, it looks sane as far as we can check without
381 * actually mapping the pack file.
382 */
383 p = xmalloc(sizeof(*p) + path_len + 2);
384 strcpy(p->pack_name, path);
385 p->index_size = idx_size;
386 p->pack_size = st.st_size;
387 p->index_base = idx_map;
388 p->next = NULL;
389 p->pack_base = NULL;
390 p->pack_last_used = 0;
391 return p;
392 }
394 static void prepare_packed_git_one(char *objdir)
395 {
396 char path[PATH_MAX];
397 int len;
398 DIR *dir;
399 struct dirent *de;
401 sprintf(path, "%s/pack", objdir);
402 len = strlen(path);
403 dir = opendir(path);
404 if (!dir)
405 return;
406 path[len++] = '/';
407 while ((de = readdir(dir)) != NULL) {
408 int namelen = strlen(de->d_name);
409 struct packed_git *p;
411 if (strcmp(de->d_name + namelen - 4, ".idx"))
412 continue;
414 /* we have .idx. Is it a file we can map? */
415 strcpy(path + len, de->d_name);
416 p = add_packed_git(path, len + namelen);
417 if (!p)
418 continue;
419 p->next = packed_git;
420 packed_git = p;
421 }
422 }
424 void prepare_packed_git(void)
425 {
426 int i;
427 static int run_once = 0;
429 if (run_once++)
430 return;
432 prepare_packed_git_one(get_object_directory());
433 prepare_alt_odb();
434 for (i = 0; alt_odb[i].base != NULL; i++) {
435 alt_odb[i].name[0] = 0;
436 prepare_packed_git_one(alt_odb[i].base);
437 }
438 }
440 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
441 {
442 char header[100];
443 unsigned char real_sha1[20];
444 SHA_CTX c;
446 SHA1_Init(&c);
447 SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
448 SHA1_Update(&c, map, size);
449 SHA1_Final(real_sha1, &c);
450 return memcmp(sha1, real_sha1, 20) ? -1 : 0;
451 }
453 static void *map_sha1_file_internal(const unsigned char *sha1,
454 unsigned long *size,
455 int say_error)
456 {
457 struct stat st;
458 void *map;
459 int fd;
460 char *filename = find_sha1_file(sha1, &st);
462 if (!filename) {
463 if (say_error)
464 error("cannot map sha1 file %s", sha1_to_hex(sha1));
465 return NULL;
466 }
468 fd = open(filename, O_RDONLY | sha1_file_open_flag);
469 if (fd < 0) {
470 /* See if it works without O_NOATIME */
471 switch (sha1_file_open_flag) {
472 default:
473 fd = open(filename, O_RDONLY);
474 if (fd >= 0)
475 break;
476 /* Fallthrough */
477 case 0:
478 if (say_error)
479 perror(filename);
480 return NULL;
481 }
483 /* If it failed once, it will probably fail again.
484 * Stop using O_NOATIME
485 */
486 sha1_file_open_flag = 0;
487 }
488 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
489 close(fd);
490 if (-1 == (int)(long)map)
491 return NULL;
492 *size = st.st_size;
493 return map;
494 }
496 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
497 {
498 return map_sha1_file_internal(sha1, size, 1);
499 }
501 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
502 {
503 /* Get the data stream */
504 memset(stream, 0, sizeof(*stream));
505 stream->next_in = map;
506 stream->avail_in = mapsize;
507 stream->next_out = buffer;
508 stream->avail_out = size;
510 inflateInit(stream);
511 return inflate(stream, 0);
512 }
514 void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
515 {
516 int bytes = strlen(buffer) + 1;
517 unsigned char *buf = xmalloc(1+size);
519 memcpy(buf, buffer + bytes, stream->total_out - bytes);
520 bytes = stream->total_out - bytes;
521 if (bytes < size) {
522 stream->next_out = buf + bytes;
523 stream->avail_out = size - bytes;
524 while (inflate(stream, Z_FINISH) == Z_OK)
525 /* nothing */;
526 }
527 buf[size] = 0;
528 inflateEnd(stream);
529 return buf;
530 }
532 /*
533 * We used to just use "sscanf()", but that's actually way
534 * too permissive for what we want to check. So do an anal
535 * object header parse by hand.
536 */
537 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
538 {
539 int i;
540 unsigned long size;
542 /*
543 * The type can be at most ten bytes (including the
544 * terminating '\0' that we add), and is followed by
545 * a space.
546 */
547 i = 10;
548 for (;;) {
549 char c = *hdr++;
550 if (c == ' ')
551 break;
552 if (!--i)
553 return -1;
554 *type++ = c;
555 }
556 *type = 0;
558 /*
559 * The length must follow immediately, and be in canonical
560 * decimal format (ie "010" is not valid).
561 */
562 size = *hdr++ - '0';
563 if (size > 9)
564 return -1;
565 if (size) {
566 for (;;) {
567 unsigned long c = *hdr - '0';
568 if (c > 9)
569 break;
570 hdr++;
571 size = size * 10 + c;
572 }
573 }
574 *sizep = size;
576 /*
577 * The length must be followed by a zero byte
578 */
579 return *hdr ? -1 : 0;
580 }
582 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
583 {
584 int ret;
585 z_stream stream;
586 char hdr[8192];
588 ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
589 if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
590 return NULL;
592 return unpack_sha1_rest(&stream, hdr, *size);
593 }
595 static unsigned long parse_delta_size(unsigned char **p)
596 {
597 unsigned char c;
598 unsigned long size = 0;
599 unsigned shift = 0;
600 unsigned char *data = *p;
602 do {
603 c = *data++;
604 size += (c & 0x7f) << shift;
605 shift += 7;
606 } while (c & 0x80);
607 *p = data;
608 return size;
609 }
611 static int packed_delta_info(unsigned char *base_sha1,
612 unsigned long delta_size,
613 unsigned long left,
614 char *type,
615 unsigned long *sizep)
616 {
617 unsigned char *data;
618 unsigned char delta_head[64];
619 unsigned long data_size, result_size, base_size, verify_base_size;
620 z_stream stream;
621 int st;
623 if (left < 20)
624 die("truncated pack file");
625 if (sha1_object_info(base_sha1, type, &base_size))
626 die("cannot get info for delta-pack base");
628 data = base_sha1 + 20;
629 data_size = left - 20;
631 memset(&stream, 0, sizeof(stream));
633 stream.next_in = data;
634 stream.avail_in = data_size;
635 stream.next_out = delta_head;
636 stream.avail_out = sizeof(delta_head);
638 inflateInit(&stream);
639 st = inflate(&stream, Z_FINISH);
640 inflateEnd(&stream);
641 if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head))
642 die("delta data unpack-initial failed");
644 /* Examine the initial part of the delta to figure out
645 * the result size. Verify the base size while we are at it.
646 */
647 data = delta_head;
648 verify_base_size = parse_delta_size(&data);
649 result_size = parse_delta_size(&data);
650 if (verify_base_size != base_size)
651 die("delta base size mismatch");
653 *sizep = result_size;
654 return 0;
655 }
657 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
658 enum object_type *type, unsigned long *sizep)
659 {
660 unsigned shift;
661 unsigned char *pack, c;
662 unsigned long size;
664 if (offset >= p->pack_size)
665 die("object offset outside of pack file");
667 pack = p->pack_base + offset;
668 c = *pack++;
669 offset++;
670 *type = (c >> 4) & 7;
671 size = c & 15;
672 shift = 4;
673 while (c & 0x80) {
674 if (offset >= p->pack_size)
675 die("object offset outside of pack file");
676 c = *pack++;
677 offset++;
678 size += (c & 0x7f) << shift;
679 shift += 7;
680 }
681 *sizep = size;
682 return offset;
683 }
685 static int packed_object_info(struct pack_entry *entry,
686 char *type, unsigned long *sizep)
687 {
688 struct packed_git *p = entry->p;
689 unsigned long offset, size, left;
690 unsigned char *pack;
691 enum object_type kind;
693 if (use_packed_git(p))
694 die("cannot map packed file");
696 offset = unpack_object_header(p, entry->offset, &kind, &size);
697 pack = p->pack_base + offset;
698 left = p->pack_size - offset;
700 switch (kind) {
701 case OBJ_DELTA:
702 return packed_delta_info(pack, size, left, type, sizep);
703 break;
704 case OBJ_COMMIT:
705 strcpy(type, "commit");
706 break;
707 case OBJ_TREE:
708 strcpy(type, "tree");
709 break;
710 case OBJ_BLOB:
711 strcpy(type, "blob");
712 break;
713 case OBJ_TAG:
714 strcpy(type, "tag");
715 break;
716 default:
717 die("corrupted pack file");
718 }
719 *sizep = size;
720 return 0;
721 }
723 /* forward declaration for a mutually recursive function */
724 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
726 static void *unpack_delta_entry(unsigned char *base_sha1,
727 unsigned long delta_size,
728 unsigned long left,
729 char *type,
730 unsigned long *sizep)
731 {
732 void *data, *delta_data, *result, *base;
733 unsigned long data_size, result_size, base_size;
734 z_stream stream;
735 int st;
737 if (left < 20)
738 die("truncated pack file");
739 data = base_sha1 + 20;
740 data_size = left - 20;
741 delta_data = xmalloc(delta_size);
743 memset(&stream, 0, sizeof(stream));
745 stream.next_in = data;
746 stream.avail_in = data_size;
747 stream.next_out = delta_data;
748 stream.avail_out = delta_size;
750 inflateInit(&stream);
751 st = inflate(&stream, Z_FINISH);
752 inflateEnd(&stream);
753 if ((st != Z_STREAM_END) || stream.total_out != delta_size)
754 die("delta data unpack failed");
756 /* This may recursively unpack the base, which is what we want */
757 base = read_sha1_file(base_sha1, type, &base_size);
758 if (!base)
759 die("failed to read delta-pack base object %s",
760 sha1_to_hex(base_sha1));
761 result = patch_delta(base, base_size,
762 delta_data, delta_size,
763 &result_size);
764 if (!result)
765 die("failed to apply delta");
766 free(delta_data);
767 free(base);
768 *sizep = result_size;
769 return result;
770 }
772 static void *unpack_non_delta_entry(unsigned char *data,
773 unsigned long size,
774 unsigned long left)
775 {
776 int st;
777 z_stream stream;
778 char *buffer;
780 buffer = xmalloc(size + 1);
781 buffer[size] = 0;
782 memset(&stream, 0, sizeof(stream));
783 stream.next_in = data;
784 stream.avail_in = left;
785 stream.next_out = buffer;
786 stream.avail_out = size;
788 inflateInit(&stream);
789 st = inflate(&stream, Z_FINISH);
790 inflateEnd(&stream);
791 if ((st != Z_STREAM_END) || stream.total_out != size) {
792 free(buffer);
793 return NULL;
794 }
796 return buffer;
797 }
799 static void *unpack_entry(struct pack_entry *entry,
800 char *type, unsigned long *sizep)
801 {
802 struct packed_git *p = entry->p;
803 unsigned long offset, size, left;
804 unsigned char *pack;
805 enum object_type kind;
807 if (use_packed_git(p))
808 die("cannot map packed file");
810 offset = unpack_object_header(p, entry->offset, &kind, &size);
811 pack = p->pack_base + offset;
812 left = p->pack_size - offset;
813 switch (kind) {
814 case OBJ_DELTA:
815 return unpack_delta_entry(pack, size, left, type, sizep);
816 case OBJ_COMMIT:
817 strcpy(type, "commit");
818 break;
819 case OBJ_TREE:
820 strcpy(type, "tree");
821 break;
822 case OBJ_BLOB:
823 strcpy(type, "blob");
824 break;
825 case OBJ_TAG:
826 strcpy(type, "tag");
827 break;
828 default:
829 die("corrupted pack file");
830 }
831 *sizep = size;
832 return unpack_non_delta_entry(pack, size, left);
833 }
835 int num_packed_objects(const struct packed_git *p)
836 {
837 /* See check_packed_git_idx and pack-objects.c */
838 return (p->index_size - 20 - 20 - 4*256) / 24;
839 }
841 int nth_packed_object_sha1(const struct packed_git *p, int n,
842 unsigned char* sha1)
843 {
844 void *index = p->index_base + 256;
845 if (n < 0 || num_packed_objects(p) <= n)
846 return -1;
847 memcpy(sha1, (index + 24 * n + 4), 20);
848 return 0;
849 }
851 static int find_pack_entry_1(const unsigned char *sha1,
852 struct pack_entry *e, struct packed_git *p)
853 {
854 int *level1_ofs = p->index_base;
855 int hi = ntohl(level1_ofs[*sha1]);
856 int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
857 void *index = p->index_base + 256;
859 do {
860 int mi = (lo + hi) / 2;
861 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
862 if (!cmp) {
863 e->offset = ntohl(*((int*)(index + 24 * mi)));
864 memcpy(e->sha1, sha1, 20);
865 e->p = p;
866 return 1;
867 }
868 if (cmp > 0)
869 hi = mi;
870 else
871 lo = mi+1;
872 } while (lo < hi);
873 return 0;
874 }
876 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
877 {
878 struct packed_git *p;
879 prepare_packed_git();
881 for (p = packed_git; p; p = p->next) {
882 if (find_pack_entry_1(sha1, e, p))
883 return 1;
884 }
885 return 0;
886 }
888 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
889 {
890 int status;
891 unsigned long mapsize, size;
892 void *map;
893 z_stream stream;
894 char hdr[128];
896 map = map_sha1_file_internal(sha1, &mapsize, 0);
897 if (!map) {
898 struct pack_entry e;
900 if (!find_pack_entry(sha1, &e))
901 return error("unable to find %s", sha1_to_hex(sha1));
902 if (!packed_object_info(&e, type, sizep))
903 return 0;
904 /* sheesh */
905 map = unpack_entry(&e, type, sizep);
906 free(map);
907 return (map == NULL) ? 0 : -1;
908 }
909 if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
910 status = error("unable to unpack %s header",
911 sha1_to_hex(sha1));
912 if (parse_sha1_header(hdr, type, &size) < 0)
913 status = error("unable to parse %s header", sha1_to_hex(sha1));
914 else {
915 status = 0;
916 *sizep = size;
917 }
918 inflateEnd(&stream);
919 munmap(map, mapsize);
920 return status;
921 }
923 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
924 {
925 struct pack_entry e;
927 if (!find_pack_entry(sha1, &e)) {
928 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
929 return NULL;
930 }
931 return unpack_entry(&e, type, size);
932 }
934 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
935 {
936 unsigned long mapsize;
937 void *map, *buf;
939 map = map_sha1_file_internal(sha1, &mapsize, 0);
940 if (map) {
941 buf = unpack_sha1_file(map, mapsize, type, size);
942 munmap(map, mapsize);
943 return buf;
944 }
945 return read_packed_sha1(sha1, type, size);
946 }
948 void *read_object_with_reference(const unsigned char *sha1,
949 const char *required_type,
950 unsigned long *size,
951 unsigned char *actual_sha1_return)
952 {
953 char type[20];
954 void *buffer;
955 unsigned long isize;
956 unsigned char actual_sha1[20];
958 memcpy(actual_sha1, sha1, 20);
959 while (1) {
960 int ref_length = -1;
961 const char *ref_type = NULL;
963 buffer = read_sha1_file(actual_sha1, type, &isize);
964 if (!buffer)
965 return NULL;
966 if (!strcmp(type, required_type)) {
967 *size = isize;
968 if (actual_sha1_return)
969 memcpy(actual_sha1_return, actual_sha1, 20);
970 return buffer;
971 }
972 /* Handle references */
973 else if (!strcmp(type, "commit"))
974 ref_type = "tree ";
975 else if (!strcmp(type, "tag"))
976 ref_type = "object ";
977 else {
978 free(buffer);
979 return NULL;
980 }
981 ref_length = strlen(ref_type);
983 if (memcmp(buffer, ref_type, ref_length) ||
984 get_sha1_hex(buffer + ref_length, actual_sha1)) {
985 free(buffer);
986 return NULL;
987 }
988 /* Now we have the ID of the referred-to object in
989 * actual_sha1. Check again. */
990 }
991 }
993 static char *write_sha1_file_prepare(void *buf,
994 unsigned long len,
995 const char *type,
996 unsigned char *sha1,
997 unsigned char *hdr,
998 int *hdrlen)
999 {
1000 SHA_CTX c;
1002 /* Generate the header */
1003 *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1005 /* Sha1.. */
1006 SHA1_Init(&c);
1007 SHA1_Update(&c, hdr, *hdrlen);
1008 SHA1_Update(&c, buf, len);
1009 SHA1_Final(sha1, &c);
1011 return sha1_file_name(sha1);
1012 }
1014 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1015 {
1016 int size;
1017 unsigned char *compressed;
1018 z_stream stream;
1019 unsigned char sha1[20];
1020 char *filename;
1021 static char tmpfile[PATH_MAX];
1022 unsigned char hdr[50];
1023 int fd, hdrlen, ret;
1025 /* Normally if we have it in the pack then we do not bother writing
1026 * it out into .git/objects/??/?{38} file.
1027 */
1028 filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1029 if (returnsha1)
1030 memcpy(returnsha1, sha1, 20);
1031 if (has_sha1_file(sha1))
1032 return 0;
1033 fd = open(filename, O_RDONLY);
1034 if (fd >= 0) {
1035 /*
1036 * FIXME!!! We might do collision checking here, but we'd
1037 * need to uncompress the old file and check it. Later.
1038 */
1039 close(fd);
1040 return 0;
1041 }
1043 if (errno != ENOENT) {
1044 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1045 return -1;
1046 }
1048 snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1050 fd = mkstemp(tmpfile);
1051 if (fd < 0) {
1052 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1053 return -1;
1054 }
1056 /* Set it up */
1057 memset(&stream, 0, sizeof(stream));
1058 deflateInit(&stream, Z_BEST_COMPRESSION);
1059 size = deflateBound(&stream, len+hdrlen);
1060 compressed = xmalloc(size);
1062 /* Compress it */
1063 stream.next_out = compressed;
1064 stream.avail_out = size;
1066 /* First header.. */
1067 stream.next_in = hdr;
1068 stream.avail_in = hdrlen;
1069 while (deflate(&stream, 0) == Z_OK)
1070 /* nothing */;
1072 /* Then the data itself.. */
1073 stream.next_in = buf;
1074 stream.avail_in = len;
1075 while (deflate(&stream, Z_FINISH) == Z_OK)
1076 /* nothing */;
1077 deflateEnd(&stream);
1078 size = stream.total_out;
1080 if (write(fd, compressed, size) != size)
1081 die("unable to write file");
1082 fchmod(fd, 0444);
1083 close(fd);
1084 free(compressed);
1086 ret = link(tmpfile, filename);
1087 if (ret < 0) {
1088 ret = errno;
1090 /*
1091 * Coda hack - coda doesn't like cross-directory links,
1092 * so we fall back to a rename, which will mean that it
1093 * won't be able to check collisions, but that's not a
1094 * big deal.
1095 *
1096 * When this succeeds, we just return 0. We have nothing
1097 * left to unlink.
1098 */
1099 if (ret == EXDEV && !rename(tmpfile, filename))
1100 return 0;
1101 }
1102 unlink(tmpfile);
1103 if (ret) {
1104 if (ret != EEXIST) {
1105 fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1106 return -1;
1107 }
1108 /* FIXME!!! Collision check here ? */
1109 }
1111 return 0;
1112 }
1114 int write_sha1_from_fd(const unsigned char *sha1, int fd)
1115 {
1116 char *filename = sha1_file_name(sha1);
1118 int local;
1119 z_stream stream;
1120 unsigned char real_sha1[20];
1121 unsigned char buf[4096];
1122 unsigned char discard[4096];
1123 int ret;
1124 SHA_CTX c;
1126 local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
1128 if (local < 0)
1129 return error("Couldn't open %s\n", filename);
1131 memset(&stream, 0, sizeof(stream));
1133 inflateInit(&stream);
1135 SHA1_Init(&c);
1137 do {
1138 ssize_t size;
1139 size = read(fd, buf, 4096);
1140 if (size <= 0) {
1141 close(local);
1142 unlink(filename);
1143 if (!size)
1144 return error("Connection closed?");
1145 perror("Reading from connection");
1146 return -1;
1147 }
1148 write(local, buf, size);
1149 stream.avail_in = size;
1150 stream.next_in = buf;
1151 do {
1152 stream.next_out = discard;
1153 stream.avail_out = sizeof(discard);
1154 ret = inflate(&stream, Z_SYNC_FLUSH);
1155 SHA1_Update(&c, discard, sizeof(discard) -
1156 stream.avail_out);
1157 } while (stream.avail_in && ret == Z_OK);
1159 } while (ret == Z_OK);
1160 inflateEnd(&stream);
1162 close(local);
1163 SHA1_Final(real_sha1, &c);
1164 if (ret != Z_STREAM_END) {
1165 unlink(filename);
1166 return error("File %s corrupted", sha1_to_hex(sha1));
1167 }
1168 if (memcmp(sha1, real_sha1, 20)) {
1169 unlink(filename);
1170 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1171 }
1173 return 0;
1174 }
1176 int has_sha1_file(const unsigned char *sha1)
1177 {
1178 struct stat st;
1179 struct pack_entry e;
1181 if (find_sha1_file(sha1, &st))
1182 return 1;
1183 return find_pack_entry(sha1, &e);
1184 }
1186 int index_fd(unsigned char *sha1, int fd, struct stat *st)
1187 {
1188 unsigned long size = st->st_size;
1189 void *buf;
1190 int ret;
1192 buf = "";
1193 if (size)
1194 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1195 close(fd);
1196 if ((int)(long)buf == -1)
1197 return -1;
1199 ret = write_sha1_file(buf, size, "blob", sha1);
1200 if (size)
1201 munmap(buf, size);
1202 return ret;
1203 }