Merge branch 'maint'
[git] / sha1_file.c
1 /*
2  * GIT - The information manager from hell
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  *
6  * This handles basic git sha1 object files - packing, unpacking,
7  * creation etc.
8  */
9 #include "cache.h"
10 #include "delta.h"
11 #include "pack.h"
12 #include "blob.h"
13 #include "commit.h"
14 #include "tag.h"
15 #include "tree.h"
16
17 #ifndef O_NOATIME
18 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
19 #define O_NOATIME 01000000
20 #else
21 #define O_NOATIME 0
22 #endif
23 #endif
24
25 const unsigned char null_sha1[20];
26
27 static unsigned int sha1_file_open_flag = O_NOATIME;
28
29 signed char hexval_table[256] = {
30          -1, -1, -1, -1, -1, -1, -1, -1,                /* 00-07 */
31          -1, -1, -1, -1, -1, -1, -1, -1,                /* 08-0f */
32          -1, -1, -1, -1, -1, -1, -1, -1,                /* 10-17 */
33          -1, -1, -1, -1, -1, -1, -1, -1,                /* 18-1f */
34          -1, -1, -1, -1, -1, -1, -1, -1,                /* 20-27 */
35          -1, -1, -1, -1, -1, -1, -1, -1,                /* 28-2f */
36           0,  1,  2,  3,  4,  5,  6,  7,                /* 30-37 */
37           8,  9, -1, -1, -1, -1, -1, -1,                /* 38-3f */
38          -1, 10, 11, 12, 13, 14, 15, -1,                /* 40-47 */
39          -1, -1, -1, -1, -1, -1, -1, -1,                /* 48-4f */
40          -1, -1, -1, -1, -1, -1, -1, -1,                /* 50-57 */
41          -1, -1, -1, -1, -1, -1, -1, -1,                /* 58-5f */
42          -1, 10, 11, 12, 13, 14, 15, -1,                /* 60-67 */
43          -1, -1, -1, -1, -1, -1, -1, -1,                /* 68-67 */
44          -1, -1, -1, -1, -1, -1, -1, -1,                /* 70-77 */
45          -1, -1, -1, -1, -1, -1, -1, -1,                /* 78-7f */
46          -1, -1, -1, -1, -1, -1, -1, -1,                /* 80-87 */
47          -1, -1, -1, -1, -1, -1, -1, -1,                /* 88-8f */
48          -1, -1, -1, -1, -1, -1, -1, -1,                /* 90-97 */
49          -1, -1, -1, -1, -1, -1, -1, -1,                /* 98-9f */
50          -1, -1, -1, -1, -1, -1, -1, -1,                /* a0-a7 */
51          -1, -1, -1, -1, -1, -1, -1, -1,                /* a8-af */
52          -1, -1, -1, -1, -1, -1, -1, -1,                /* b0-b7 */
53          -1, -1, -1, -1, -1, -1, -1, -1,                /* b8-bf */
54          -1, -1, -1, -1, -1, -1, -1, -1,                /* c0-c7 */
55          -1, -1, -1, -1, -1, -1, -1, -1,                /* c8-cf */
56          -1, -1, -1, -1, -1, -1, -1, -1,                /* d0-d7 */
57          -1, -1, -1, -1, -1, -1, -1, -1,                /* d8-df */
58          -1, -1, -1, -1, -1, -1, -1, -1,                /* e0-e7 */
59          -1, -1, -1, -1, -1, -1, -1, -1,                /* e8-ef */
60          -1, -1, -1, -1, -1, -1, -1, -1,                /* f0-f7 */
61          -1, -1, -1, -1, -1, -1, -1, -1,                /* f8-ff */
62 };
63
64 int get_sha1_hex(const char *hex, unsigned char *sha1)
65 {
66         int i;
67         for (i = 0; i < 20; i++) {
68                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
69                 if (val & ~0xff)
70                         return -1;
71                 *sha1++ = val;
72                 hex += 2;
73         }
74         return 0;
75 }
76
77 int safe_create_leading_directories(char *path)
78 {
79         char *pos = path;
80         struct stat st;
81
82         if (*pos == '/')
83                 pos++;
84
85         while (pos) {
86                 pos = strchr(pos, '/');
87                 if (!pos)
88                         break;
89                 *pos = 0;
90                 if (!stat(path, &st)) {
91                         /* path exists */
92                         if (!S_ISDIR(st.st_mode)) {
93                                 *pos = '/';
94                                 return -3;
95                         }
96                 }
97                 else if (mkdir(path, 0777)) {
98                         *pos = '/';
99                         return -1;
100                 }
101                 else if (adjust_shared_perm(path)) {
102                         *pos = '/';
103                         return -2;
104                 }
105                 *pos++ = '/';
106         }
107         return 0;
108 }
109
110 char * sha1_to_hex(const unsigned char *sha1)
111 {
112         static int bufno;
113         static char hexbuffer[4][50];
114         static const char hex[] = "0123456789abcdef";
115         char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
116         int i;
117
118         for (i = 0; i < 20; i++) {
119                 unsigned int val = *sha1++;
120                 *buf++ = hex[val >> 4];
121                 *buf++ = hex[val & 0xf];
122         }
123         *buf = '\0';
124
125         return buffer;
126 }
127
128 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
129 {
130         int i;
131         for (i = 0; i < 20; i++) {
132                 static char hex[] = "0123456789abcdef";
133                 unsigned int val = sha1[i];
134                 char *pos = pathbuf + i*2 + (i > 0);
135                 *pos++ = hex[val >> 4];
136                 *pos = hex[val & 0xf];
137         }
138 }
139
140 /*
141  * NOTE! This returns a statically allocated buffer, so you have to be
142  * careful about using it. Do a "xstrdup()" if you need to save the
143  * filename.
144  *
145  * Also note that this returns the location for creating.  Reading
146  * SHA1 file can happen from any alternate directory listed in the
147  * DB_ENVIRONMENT environment variable if it is not found in
148  * the primary object database.
149  */
150 char *sha1_file_name(const unsigned char *sha1)
151 {
152         static char *name, *base;
153
154         if (!base) {
155                 const char *sha1_file_directory = get_object_directory();
156                 int len = strlen(sha1_file_directory);
157                 base = xmalloc(len + 60);
158                 memcpy(base, sha1_file_directory, len);
159                 memset(base+len, 0, 60);
160                 base[len] = '/';
161                 base[len+3] = '/';
162                 name = base + len + 1;
163         }
164         fill_sha1_path(name, sha1);
165         return base;
166 }
167
168 char *sha1_pack_name(const unsigned char *sha1)
169 {
170         static const char hex[] = "0123456789abcdef";
171         static char *name, *base, *buf;
172         int i;
173
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                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
179                 name = base + len + 11;
180         }
181
182         buf = name;
183
184         for (i = 0; i < 20; i++) {
185                 unsigned int val = *sha1++;
186                 *buf++ = hex[val >> 4];
187                 *buf++ = hex[val & 0xf];
188         }
189         
190         return base;
191 }
192
193 char *sha1_pack_index_name(const unsigned char *sha1)
194 {
195         static const char hex[] = "0123456789abcdef";
196         static char *name, *base, *buf;
197         int i;
198
199         if (!base) {
200                 const char *sha1_file_directory = get_object_directory();
201                 int len = strlen(sha1_file_directory);
202                 base = xmalloc(len + 60);
203                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
204                 name = base + len + 11;
205         }
206
207         buf = name;
208
209         for (i = 0; i < 20; i++) {
210                 unsigned int val = *sha1++;
211                 *buf++ = hex[val >> 4];
212                 *buf++ = hex[val & 0xf];
213         }
214         
215         return base;
216 }
217
218 struct alternate_object_database *alt_odb_list;
219 static struct alternate_object_database **alt_odb_tail;
220
221 static void read_info_alternates(const char * alternates, int depth);
222
223 /*
224  * Prepare alternate object database registry.
225  *
226  * The variable alt_odb_list points at the list of struct
227  * alternate_object_database.  The elements on this list come from
228  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
229  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
230  * whose contents is similar to that environment variable but can be
231  * LF separated.  Its base points at a statically allocated buffer that
232  * contains "/the/directory/corresponding/to/.git/objects/...", while
233  * its name points just after the slash at the end of ".git/objects/"
234  * in the example above, and has enough space to hold 40-byte hex
235  * SHA1, an extra slash for the first level indirection, and the
236  * terminating NUL.
237  */
238 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
239 {
240         struct stat st;
241         const char *objdir = get_object_directory();
242         struct alternate_object_database *ent;
243         struct alternate_object_database *alt;
244         /* 43 = 40-byte + 2 '/' + terminating NUL */
245         int pfxlen = len;
246         int entlen = pfxlen + 43;
247         int base_len = -1;
248
249         if (*entry != '/' && relative_base) {
250                 /* Relative alt-odb */
251                 if (base_len < 0)
252                         base_len = strlen(relative_base) + 1;
253                 entlen += base_len;
254                 pfxlen += base_len;
255         }
256         ent = xmalloc(sizeof(*ent) + entlen);
257
258         if (*entry != '/' && relative_base) {
259                 memcpy(ent->base, relative_base, base_len - 1);
260                 ent->base[base_len - 1] = '/';
261                 memcpy(ent->base + base_len, entry, len);
262         }
263         else
264                 memcpy(ent->base, entry, pfxlen);
265
266         ent->name = ent->base + pfxlen + 1;
267         ent->base[pfxlen + 3] = '/';
268         ent->base[pfxlen] = ent->base[entlen-1] = 0;
269
270         /* Detect cases where alternate disappeared */
271         if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
272                 error("object directory %s does not exist; "
273                       "check .git/objects/info/alternates.",
274                       ent->base);
275                 free(ent);
276                 return -1;
277         }
278
279         /* Prevent the common mistake of listing the same
280          * thing twice, or object directory itself.
281          */
282         for (alt = alt_odb_list; alt; alt = alt->next) {
283                 if (!memcmp(ent->base, alt->base, pfxlen)) {
284                         free(ent);
285                         return -1;
286                 }
287         }
288         if (!memcmp(ent->base, objdir, pfxlen)) {
289                 free(ent);
290                 return -1;
291         }
292
293         /* add the alternate entry */
294         *alt_odb_tail = ent;
295         alt_odb_tail = &(ent->next);
296         ent->next = NULL;
297
298         /* recursively add alternates */
299         read_info_alternates(ent->base, depth + 1);
300
301         ent->base[pfxlen] = '/';
302
303         return 0;
304 }
305
306 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
307                                  const char *relative_base, int depth)
308 {
309         const char *cp, *last;
310
311         if (depth > 5) {
312                 error("%s: ignoring alternate object stores, nesting too deep.",
313                                 relative_base);
314                 return;
315         }
316
317         last = alt;
318         while (last < ep) {
319                 cp = last;
320                 if (cp < ep && *cp == '#') {
321                         while (cp < ep && *cp != sep)
322                                 cp++;
323                         last = cp + 1;
324                         continue;
325                 }
326                 while (cp < ep && *cp != sep)
327                         cp++;
328                 if (last != cp) {
329                         if ((*last != '/') && depth) {
330                                 error("%s: ignoring relative alternate object store %s",
331                                                 relative_base, last);
332                         } else {
333                                 link_alt_odb_entry(last, cp - last,
334                                                 relative_base, depth);
335                         }
336                 }
337                 while (cp < ep && *cp == sep)
338                         cp++;
339                 last = cp;
340         }
341 }
342
343 static void read_info_alternates(const char * relative_base, int depth)
344 {
345         char *map;
346         struct stat st;
347         char path[PATH_MAX];
348         int fd;
349
350         sprintf(path, "%s/info/alternates", relative_base);
351         fd = open(path, O_RDONLY);
352         if (fd < 0)
353                 return;
354         if (fstat(fd, &st) || (st.st_size == 0)) {
355                 close(fd);
356                 return;
357         }
358         map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
359         close(fd);
360
361         link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
362
363         munmap(map, st.st_size);
364 }
365
366 void prepare_alt_odb(void)
367 {
368         const char *alt;
369
370         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
371         if (!alt) alt = "";
372
373         if (alt_odb_tail)
374                 return;
375         alt_odb_tail = &alt_odb_list;
376         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
377
378         read_info_alternates(get_object_directory(), 0);
379 }
380
381 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
382 {
383         char *name = sha1_file_name(sha1);
384         struct alternate_object_database *alt;
385
386         if (!stat(name, st))
387                 return name;
388         prepare_alt_odb();
389         for (alt = alt_odb_list; alt; alt = alt->next) {
390                 name = alt->name;
391                 fill_sha1_path(name, sha1);
392                 if (!stat(alt->base, st))
393                         return alt->base;
394         }
395         return NULL;
396 }
397
398 static unsigned int pack_used_ctr;
399 static unsigned int pack_mmap_calls;
400 static unsigned int peak_pack_open_windows;
401 static unsigned int pack_open_windows;
402 static size_t peak_pack_mapped;
403 static size_t pack_mapped;
404 static size_t page_size;
405 struct packed_git *packed_git;
406
407 void pack_report()
408 {
409         fprintf(stderr,
410                 "pack_report: getpagesize()            = %10lu\n"
411                 "pack_report: core.packedGitWindowSize = %10lu\n"
412                 "pack_report: core.packedGitLimit      = %10lu\n",
413                 page_size,
414                 packed_git_window_size,
415                 packed_git_limit);
416         fprintf(stderr,
417                 "pack_report: pack_used_ctr            = %10u\n"
418                 "pack_report: pack_mmap_calls          = %10u\n"
419                 "pack_report: pack_open_windows        = %10u / %10u\n"
420                 "pack_report: pack_mapped              = %10lu / %10lu\n",
421                 pack_used_ctr,
422                 pack_mmap_calls,
423                 pack_open_windows, peak_pack_open_windows,
424                 pack_mapped, peak_pack_mapped);
425 }
426
427 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
428                                 void **idx_map_)
429 {
430         void *idx_map;
431         unsigned int *index;
432         unsigned long idx_size;
433         int nr, i;
434         int fd = open(path, O_RDONLY);
435         struct stat st;
436         if (fd < 0)
437                 return -1;
438         if (fstat(fd, &st)) {
439                 close(fd);
440                 return -1;
441         }
442         idx_size = st.st_size;
443         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
444         close(fd);
445
446         index = idx_map;
447         *idx_map_ = idx_map;
448         *idx_size_ = idx_size;
449
450         /* check index map */
451         if (idx_size < 4*256 + 20 + 20)
452                 return error("index file too small");
453         nr = 0;
454         for (i = 0; i < 256; i++) {
455                 unsigned int n = ntohl(index[i]);
456                 if (n < nr)
457                         return error("non-monotonic index");
458                 nr = n;
459         }
460
461         /*
462          * Total size:
463          *  - 256 index entries 4 bytes each
464          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
465          *  - 20-byte SHA1 of the packfile
466          *  - 20-byte SHA1 file checksum
467          */
468         if (idx_size != 4*256 + nr * 24 + 20 + 20)
469                 return error("wrong index file size");
470
471         return 0;
472 }
473
474 static void scan_windows(struct packed_git *p,
475         struct packed_git **lru_p,
476         struct pack_window **lru_w,
477         struct pack_window **lru_l)
478 {
479         struct pack_window *w, *w_l;
480
481         for (w_l = NULL, w = p->windows; w; w = w->next) {
482                 if (!w->inuse_cnt) {
483                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
484                                 *lru_p = p;
485                                 *lru_w = w;
486                                 *lru_l = w_l;
487                         }
488                 }
489                 w_l = w;
490         }
491 }
492
493 static int unuse_one_window(struct packed_git *current)
494 {
495         struct packed_git *p, *lru_p = NULL;
496         struct pack_window *lru_w = NULL, *lru_l = NULL;
497
498         if (current)
499                 scan_windows(current, &lru_p, &lru_w, &lru_l);
500         for (p = packed_git; p; p = p->next)
501                 scan_windows(p, &lru_p, &lru_w, &lru_l);
502         if (lru_p) {
503                 munmap(lru_w->base, lru_w->len);
504                 pack_mapped -= lru_w->len;
505                 if (lru_l)
506                         lru_l->next = lru_w->next;
507                 else {
508                         lru_p->windows = lru_w->next;
509                         if (!lru_p->windows && lru_p != current) {
510                                 close(lru_p->pack_fd);
511                                 lru_p->pack_fd = -1;
512                         }
513                 }
514                 free(lru_w);
515                 pack_open_windows--;
516                 return 1;
517         }
518         return 0;
519 }
520
521 void release_pack_memory(size_t need)
522 {
523         size_t cur = pack_mapped;
524         while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
525                 ; /* nothing */
526 }
527
528 void unuse_pack(struct pack_window **w_cursor)
529 {
530         struct pack_window *w = *w_cursor;
531         if (w) {
532                 w->inuse_cnt--;
533                 *w_cursor = NULL;
534         }
535 }
536
537 static void open_packed_git(struct packed_git *p)
538 {
539         struct stat st;
540         struct pack_header hdr;
541         unsigned char sha1[20];
542         unsigned char *idx_sha1;
543         long fd_flag;
544
545         p->pack_fd = open(p->pack_name, O_RDONLY);
546         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
547                 die("packfile %s cannot be opened", p->pack_name);
548
549         /* If we created the struct before we had the pack we lack size. */
550         if (!p->pack_size) {
551                 if (!S_ISREG(st.st_mode))
552                         die("packfile %s not a regular file", p->pack_name);
553                 p->pack_size = st.st_size;
554         } else if (p->pack_size != st.st_size)
555                 die("packfile %s size changed", p->pack_name);
556
557         /* We leave these file descriptors open with sliding mmap;
558          * there is no point keeping them open across exec(), though.
559          */
560         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
561         if (fd_flag < 0)
562                 die("cannot determine file descriptor flags");
563         fd_flag |= FD_CLOEXEC;
564         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
565                 die("cannot set FD_CLOEXEC");
566
567         /* Verify we recognize this pack file format. */
568         read_or_die(p->pack_fd, &hdr, sizeof(hdr));
569         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
570                 die("file %s is not a GIT packfile", p->pack_name);
571         if (!pack_version_ok(hdr.hdr_version))
572                 die("packfile %s is version %u and not supported"
573                         " (try upgrading GIT to a newer version)",
574                         p->pack_name, ntohl(hdr.hdr_version));
575
576         /* Verify the pack matches its index. */
577         if (num_packed_objects(p) != ntohl(hdr.hdr_entries))
578                 die("packfile %s claims to have %u objects"
579                         " while index size indicates %u objects",
580                         p->pack_name, ntohl(hdr.hdr_entries),
581                         num_packed_objects(p));
582         if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
583                 die("end of packfile %s is unavailable", p->pack_name);
584         read_or_die(p->pack_fd, sha1, sizeof(sha1));
585         idx_sha1 = ((unsigned char *)p->index_base) + p->index_size - 40;
586         if (hashcmp(sha1, idx_sha1))
587                 die("packfile %s does not match index", p->pack_name);
588 }
589
590 static int in_window(struct pack_window *win, unsigned long offset)
591 {
592         /* We must promise at least 20 bytes (one hash) after the
593          * offset is available from this window, otherwise the offset
594          * is not actually in this window and a different window (which
595          * has that one hash excess) must be used.  This is to support
596          * the object header and delta base parsing routines below.
597          */
598         off_t win_off = win->offset;
599         return win_off <= offset
600                 && (offset + 20) <= (win_off + win->len);
601 }
602
603 unsigned char* use_pack(struct packed_git *p,
604                 struct pack_window **w_cursor,
605                 unsigned long offset,
606                 unsigned int *left)
607 {
608         struct pack_window *win = *w_cursor;
609
610         if (p->pack_fd == -1)
611                 open_packed_git(p);
612
613         /* Since packfiles end in a hash of their content and its
614          * pointless to ask for an offset into the middle of that
615          * hash, and the in_window function above wouldn't match
616          * don't allow an offset too close to the end of the file.
617          */
618         if (offset > (p->pack_size - 20))
619                 die("offset beyond end of packfile (truncated pack?)");
620
621         if (!win || !in_window(win, offset)) {
622                 if (win)
623                         win->inuse_cnt--;
624                 for (win = p->windows; win; win = win->next) {
625                         if (in_window(win, offset))
626                                 break;
627                 }
628                 if (!win) {
629                         if (!page_size)
630                                 page_size = getpagesize();
631                         win = xcalloc(1, sizeof(*win));
632                         win->offset = (offset / page_size) * page_size;
633                         win->len = p->pack_size - win->offset;
634                         if (win->len > packed_git_window_size)
635                                 win->len = packed_git_window_size;
636                         pack_mapped += win->len;
637                         while (packed_git_limit < pack_mapped
638                                 && unuse_one_window(p))
639                                 ; /* nothing */
640                         win->base = xmmap(NULL, win->len,
641                                 PROT_READ, MAP_PRIVATE,
642                                 p->pack_fd, win->offset);
643                         if (win->base == MAP_FAILED)
644                                 die("packfile %s cannot be mapped: %s",
645                                         p->pack_name,
646                                         strerror(errno));
647                         pack_mmap_calls++;
648                         pack_open_windows++;
649                         if (pack_mapped > peak_pack_mapped)
650                                 peak_pack_mapped = pack_mapped;
651                         if (pack_open_windows > peak_pack_open_windows)
652                                 peak_pack_open_windows = pack_open_windows;
653                         win->next = p->windows;
654                         p->windows = win;
655                 }
656         }
657         if (win != *w_cursor) {
658                 win->last_used = pack_used_ctr++;
659                 win->inuse_cnt++;
660                 *w_cursor = win;
661         }
662         offset -= win->offset;
663         if (left)
664                 *left = win->len - offset;
665         return win->base + offset;
666 }
667
668 struct packed_git *add_packed_git(char *path, int path_len, int local)
669 {
670         struct stat st;
671         struct packed_git *p;
672         unsigned long idx_size;
673         void *idx_map;
674         unsigned char sha1[20];
675
676         if (check_packed_git_idx(path, &idx_size, &idx_map))
677                 return NULL;
678
679         /* do we have a corresponding .pack file? */
680         strcpy(path + path_len - 4, ".pack");
681         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
682                 munmap(idx_map, idx_size);
683                 return NULL;
684         }
685         /* ok, it looks sane as far as we can check without
686          * actually mapping the pack file.
687          */
688         p = xmalloc(sizeof(*p) + path_len + 2);
689         strcpy(p->pack_name, path);
690         p->index_size = idx_size;
691         p->pack_size = st.st_size;
692         p->index_base = idx_map;
693         p->next = NULL;
694         p->windows = NULL;
695         p->pack_fd = -1;
696         p->pack_local = local;
697         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
698                 hashcpy(p->sha1, sha1);
699         return p;
700 }
701
702 struct packed_git *parse_pack_index(unsigned char *sha1)
703 {
704         char *path = sha1_pack_index_name(sha1);
705         return parse_pack_index_file(sha1, path);
706 }
707
708 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
709 {
710         struct packed_git *p;
711         unsigned long idx_size;
712         void *idx_map;
713         char *path;
714
715         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
716                 return NULL;
717
718         path = sha1_pack_name(sha1);
719
720         p = xmalloc(sizeof(*p) + strlen(path) + 2);
721         strcpy(p->pack_name, path);
722         p->index_size = idx_size;
723         p->pack_size = 0;
724         p->index_base = idx_map;
725         p->next = NULL;
726         p->windows = NULL;
727         p->pack_fd = -1;
728         hashcpy(p->sha1, sha1);
729         return p;
730 }
731
732 void install_packed_git(struct packed_git *pack)
733 {
734         pack->next = packed_git;
735         packed_git = pack;
736 }
737
738 static void prepare_packed_git_one(char *objdir, int local)
739 {
740         char path[PATH_MAX];
741         int len;
742         DIR *dir;
743         struct dirent *de;
744
745         sprintf(path, "%s/pack", objdir);
746         len = strlen(path);
747         dir = opendir(path);
748         if (!dir) {
749                 if (errno != ENOENT)
750                         error("unable to open object pack directory: %s: %s",
751                               path, strerror(errno));
752                 return;
753         }
754         path[len++] = '/';
755         while ((de = readdir(dir)) != NULL) {
756                 int namelen = strlen(de->d_name);
757                 struct packed_git *p;
758
759                 if (!has_extension(de->d_name, ".idx"))
760                         continue;
761
762                 /* we have .idx.  Is it a file we can map? */
763                 strcpy(path + len, de->d_name);
764                 for (p = packed_git; p; p = p->next) {
765                         if (!memcmp(path, p->pack_name, len + namelen - 4))
766                                 break;
767                 }
768                 if (p)
769                         continue;
770                 p = add_packed_git(path, len + namelen, local);
771                 if (!p)
772                         continue;
773                 p->next = packed_git;
774                 packed_git = p;
775         }
776         closedir(dir);
777 }
778
779 static int prepare_packed_git_run_once = 0;
780 void prepare_packed_git(void)
781 {
782         struct alternate_object_database *alt;
783
784         if (prepare_packed_git_run_once)
785                 return;
786         prepare_packed_git_one(get_object_directory(), 1);
787         prepare_alt_odb();
788         for (alt = alt_odb_list; alt; alt = alt->next) {
789                 alt->name[-1] = 0;
790                 prepare_packed_git_one(alt->base, 0);
791                 alt->name[-1] = '/';
792         }
793         prepare_packed_git_run_once = 1;
794 }
795
796 void reprepare_packed_git(void)
797 {
798         prepare_packed_git_run_once = 0;
799         prepare_packed_git();
800 }
801
802 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
803 {
804         unsigned char real_sha1[20];
805         hash_sha1_file(map, size, type, real_sha1);
806         return hashcmp(sha1, real_sha1) ? -1 : 0;
807 }
808
809 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
810 {
811         struct stat st;
812         void *map;
813         int fd;
814         char *filename = find_sha1_file(sha1, &st);
815
816         if (!filename) {
817                 return NULL;
818         }
819
820         fd = open(filename, O_RDONLY | sha1_file_open_flag);
821         if (fd < 0) {
822                 /* See if it works without O_NOATIME */
823                 switch (sha1_file_open_flag) {
824                 default:
825                         fd = open(filename, O_RDONLY);
826                         if (fd >= 0)
827                                 break;
828                 /* Fallthrough */
829                 case 0:
830                         return NULL;
831                 }
832
833                 /* If it failed once, it will probably fail again.
834                  * Stop using O_NOATIME
835                  */
836                 sha1_file_open_flag = 0;
837         }
838         map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
839         close(fd);
840         *size = st.st_size;
841         return map;
842 }
843
844 int legacy_loose_object(unsigned char *map)
845 {
846         unsigned int word;
847
848         /*
849          * Is it a zlib-compressed buffer? If so, the first byte
850          * must be 0x78 (15-bit window size, deflated), and the
851          * first 16-bit word is evenly divisible by 31
852          */
853         word = (map[0] << 8) + map[1];
854         if (map[0] == 0x78 && !(word % 31))
855                 return 1;
856         else
857                 return 0;
858 }
859
860 unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
861 {
862         unsigned shift;
863         unsigned char c;
864         unsigned long size;
865         unsigned long used = 0;
866
867         c = buf[used++];
868         *type = (c >> 4) & 7;
869         size = c & 15;
870         shift = 4;
871         while (c & 0x80) {
872                 if (len <= used)
873                         return 0;
874                 if (sizeof(long) * 8 <= shift)
875                         return 0;
876                 c = buf[used++];
877                 size += (c & 0x7f) << shift;
878                 shift += 7;
879         }
880         *sizep = size;
881         return used;
882 }
883
884 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
885 {
886         unsigned long size, used;
887         static const char valid_loose_object_type[8] = {
888                 0, /* OBJ_EXT */
889                 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
890                 0, /* "delta" and others are invalid in a loose object */
891         };
892         enum object_type type;
893
894         /* Get the data stream */
895         memset(stream, 0, sizeof(*stream));
896         stream->next_in = map;
897         stream->avail_in = mapsize;
898         stream->next_out = buffer;
899         stream->avail_out = bufsiz;
900
901         if (legacy_loose_object(map)) {
902                 inflateInit(stream);
903                 return inflate(stream, 0);
904         }
905
906         used = unpack_object_header_gently(map, mapsize, &type, &size);
907         if (!used || !valid_loose_object_type[type])
908                 return -1;
909         map += used;
910         mapsize -= used;
911
912         /* Set up the stream for the rest.. */
913         stream->next_in = map;
914         stream->avail_in = mapsize;
915         inflateInit(stream);
916
917         /* And generate the fake traditional header */
918         stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
919                                          type_names[type], size);
920         return 0;
921 }
922
923 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
924 {
925         int bytes = strlen(buffer) + 1;
926         unsigned char *buf = xmalloc(1+size);
927         unsigned long n;
928
929         n = stream->total_out - bytes;
930         if (n > size)
931                 n = size;
932         memcpy(buf, (char *) buffer + bytes, n);
933         bytes = n;
934         if (bytes < size) {
935                 stream->next_out = buf + bytes;
936                 stream->avail_out = size - bytes;
937                 while (inflate(stream, Z_FINISH) == Z_OK)
938                         /* nothing */;
939         }
940         buf[size] = 0;
941         inflateEnd(stream);
942         return buf;
943 }
944
945 /*
946  * We used to just use "sscanf()", but that's actually way
947  * too permissive for what we want to check. So do an anal
948  * object header parse by hand.
949  */
950 static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
951 {
952         int i;
953         unsigned long size;
954
955         /*
956          * The type can be at most ten bytes (including the 
957          * terminating '\0' that we add), and is followed by
958          * a space. 
959          */
960         i = 10;
961         for (;;) {
962                 char c = *hdr++;
963                 if (c == ' ')
964                         break;
965                 if (!--i)
966                         return -1;
967                 *type++ = c;
968         }
969         *type = 0;
970
971         /*
972          * The length must follow immediately, and be in canonical
973          * decimal format (ie "010" is not valid).
974          */
975         size = *hdr++ - '0';
976         if (size > 9)
977                 return -1;
978         if (size) {
979                 for (;;) {
980                         unsigned long c = *hdr - '0';
981                         if (c > 9)
982                                 break;
983                         hdr++;
984                         size = size * 10 + c;
985                 }
986         }
987         *sizep = size;
988
989         /*
990          * The length must be followed by a zero byte
991          */
992         return *hdr ? -1 : 0;
993 }
994
995 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
996 {
997         int ret;
998         z_stream stream;
999         char hdr[8192];
1000
1001         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1002         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
1003                 return NULL;
1004
1005         return unpack_sha1_rest(&stream, hdr, *size);
1006 }
1007
1008 static unsigned long get_delta_base(struct packed_git *p,
1009                                     struct pack_window **w_curs,
1010                                     unsigned long offset,
1011                                     enum object_type kind,
1012                                     unsigned long delta_obj_offset,
1013                                     unsigned long *base_obj_offset)
1014 {
1015         unsigned char *base_info = use_pack(p, w_curs, offset, NULL);
1016         unsigned long base_offset;
1017
1018         /* use_pack() assured us we have [base_info, base_info + 20)
1019          * as a range that we can look at without walking off the
1020          * end of the mapped window.  Its actually the hash size
1021          * that is assured.  An OFS_DELTA longer than the hash size
1022          * is stupid, as then a REF_DELTA would be smaller to store.
1023          */
1024         if (kind == OBJ_OFS_DELTA) {
1025                 unsigned used = 0;
1026                 unsigned char c = base_info[used++];
1027                 base_offset = c & 127;
1028                 while (c & 128) {
1029                         base_offset += 1;
1030                         if (!base_offset || base_offset & ~(~0UL >> 7))
1031                                 die("offset value overflow for delta base object");
1032                         c = base_info[used++];
1033                         base_offset = (base_offset << 7) + (c & 127);
1034                 }
1035                 base_offset = delta_obj_offset - base_offset;
1036                 if (base_offset >= delta_obj_offset)
1037                         die("delta base offset out of bound");
1038                 offset += used;
1039         } else if (kind == OBJ_REF_DELTA) {
1040                 /* The base entry _must_ be in the same pack */
1041                 base_offset = find_pack_entry_one(base_info, p);
1042                 if (!base_offset)
1043                         die("failed to find delta-pack base object %s",
1044                                 sha1_to_hex(base_info));
1045                 offset += 20;
1046         } else
1047                 die("I am totally screwed");
1048         *base_obj_offset = base_offset;
1049         return offset;
1050 }
1051
1052 /* forward declaration for a mutually recursive function */
1053 static int packed_object_info(struct packed_git *p, unsigned long offset,
1054                               char *type, unsigned long *sizep);
1055
1056 static int packed_delta_info(struct packed_git *p,
1057                              struct pack_window **w_curs,
1058                              unsigned long offset,
1059                              enum object_type kind,
1060                              unsigned long obj_offset,
1061                              char *type,
1062                              unsigned long *sizep)
1063 {
1064         unsigned long base_offset;
1065
1066         offset = get_delta_base(p, w_curs, offset, kind,
1067                 obj_offset, &base_offset);
1068
1069         /* We choose to only get the type of the base object and
1070          * ignore potentially corrupt pack file that expects the delta
1071          * based on a base with a wrong size.  This saves tons of
1072          * inflate() calls.
1073          */
1074         if (packed_object_info(p, base_offset, type, NULL))
1075                 die("cannot get info for delta-pack base");
1076
1077         if (sizep) {
1078                 const unsigned char *data;
1079                 unsigned char delta_head[20], *in;
1080                 unsigned long result_size;
1081                 z_stream stream;
1082                 int st;
1083
1084                 memset(&stream, 0, sizeof(stream));
1085                 stream.next_out = delta_head;
1086                 stream.avail_out = sizeof(delta_head);
1087
1088                 inflateInit(&stream);
1089                 do {
1090                         in = use_pack(p, w_curs, offset, &stream.avail_in);
1091                         stream.next_in = in;
1092                         st = inflate(&stream, Z_FINISH);
1093                         offset += stream.next_in - in;
1094                 } while ((st == Z_OK || st == Z_BUF_ERROR)
1095                         && stream.total_out < sizeof(delta_head));
1096                 inflateEnd(&stream);
1097                 if ((st != Z_STREAM_END) &&
1098                     stream.total_out != sizeof(delta_head))
1099                         die("delta data unpack-initial failed");
1100
1101                 /* Examine the initial part of the delta to figure out
1102                  * the result size.
1103                  */
1104                 data = delta_head;
1105
1106                 /* ignore base size */
1107                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1108
1109                 /* Read the result size */
1110                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1111                 *sizep = result_size;
1112         }
1113         return 0;
1114 }
1115
1116 static unsigned long unpack_object_header(struct packed_git *p,
1117                 struct pack_window **w_curs,
1118                 unsigned long offset,
1119                 enum object_type *type,
1120                 unsigned long *sizep)
1121 {
1122         unsigned char *base;
1123         unsigned int left;
1124         unsigned long used;
1125
1126         /* use_pack() assures us we have [base, base + 20) available
1127          * as a range that we can look at at.  (Its actually the hash
1128          * size that is assurred.)  With our object header encoding
1129          * the maximum deflated object size is 2^137, which is just
1130          * insane, so we know won't exceed what we have been given.
1131          */
1132         base = use_pack(p, w_curs, offset, &left);
1133         used = unpack_object_header_gently(base, left, type, sizep);
1134         if (!used)
1135                 die("object offset outside of pack file");
1136
1137         return offset + used;
1138 }
1139
1140 void packed_object_info_detail(struct packed_git *p,
1141                                unsigned long offset,
1142                                char *type,
1143                                unsigned long *size,
1144                                unsigned long *store_size,
1145                                unsigned int *delta_chain_length,
1146                                unsigned char *base_sha1)
1147 {
1148         struct pack_window *w_curs = NULL;
1149         unsigned long obj_offset, val;
1150         unsigned char *next_sha1;
1151         enum object_type kind;
1152
1153         *delta_chain_length = 0;
1154         obj_offset = offset;
1155         offset = unpack_object_header(p, &w_curs, offset, &kind, size);
1156
1157         for (;;) {
1158                 switch (kind) {
1159                 default:
1160                         die("pack %s contains unknown object type %d",
1161                             p->pack_name, kind);
1162                 case OBJ_COMMIT:
1163                 case OBJ_TREE:
1164                 case OBJ_BLOB:
1165                 case OBJ_TAG:
1166                         strcpy(type, type_names[kind]);
1167                         *store_size = 0; /* notyet */
1168                         unuse_pack(&w_curs);
1169                         return;
1170                 case OBJ_OFS_DELTA:
1171                         get_delta_base(p, &w_curs, offset, kind,
1172                                 obj_offset, &offset);
1173                         if (*delta_chain_length == 0) {
1174                                 /* TODO: find base_sha1 as pointed by offset */
1175                         }
1176                         break;
1177                 case OBJ_REF_DELTA:
1178                         next_sha1 = use_pack(p, &w_curs, offset, NULL);
1179                         if (*delta_chain_length == 0)
1180                                 hashcpy(base_sha1, next_sha1);
1181                         offset = find_pack_entry_one(next_sha1, p);
1182                         break;
1183                 }
1184                 obj_offset = offset;
1185                 offset = unpack_object_header(p, &w_curs, offset, &kind, &val);
1186                 (*delta_chain_length)++;
1187         }
1188 }
1189
1190 static int packed_object_info(struct packed_git *p, unsigned long offset,
1191                               char *type, unsigned long *sizep)
1192 {
1193         struct pack_window *w_curs = NULL;
1194         unsigned long size, obj_offset = offset;
1195         enum object_type kind;
1196         int r;
1197
1198         offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
1199
1200         switch (kind) {
1201         case OBJ_OFS_DELTA:
1202         case OBJ_REF_DELTA:
1203                 r = packed_delta_info(p, &w_curs, offset, kind,
1204                         obj_offset, type, sizep);
1205                 unuse_pack(&w_curs);
1206                 return r;
1207         case OBJ_COMMIT:
1208         case OBJ_TREE:
1209         case OBJ_BLOB:
1210         case OBJ_TAG:
1211                 strcpy(type, type_names[kind]);
1212                 unuse_pack(&w_curs);
1213                 break;
1214         default:
1215                 die("pack %s contains unknown object type %d",
1216                     p->pack_name, kind);
1217         }
1218         if (sizep)
1219                 *sizep = size;
1220         return 0;
1221 }
1222
1223 static void *unpack_compressed_entry(struct packed_git *p,
1224                                     struct pack_window **w_curs,
1225                                     unsigned long offset,
1226                                     unsigned long size)
1227 {
1228         int st;
1229         z_stream stream;
1230         unsigned char *buffer, *in;
1231
1232         buffer = xmalloc(size + 1);
1233         buffer[size] = 0;
1234         memset(&stream, 0, sizeof(stream));
1235         stream.next_out = buffer;
1236         stream.avail_out = size;
1237
1238         inflateInit(&stream);
1239         do {
1240                 in = use_pack(p, w_curs, offset, &stream.avail_in);
1241                 stream.next_in = in;
1242                 st = inflate(&stream, Z_FINISH);
1243                 offset += stream.next_in - in;
1244         } while (st == Z_OK || st == Z_BUF_ERROR);
1245         inflateEnd(&stream);
1246         if ((st != Z_STREAM_END) || stream.total_out != size) {
1247                 free(buffer);
1248                 return NULL;
1249         }
1250
1251         return buffer;
1252 }
1253
1254 static void *unpack_delta_entry(struct packed_git *p,
1255                                 struct pack_window **w_curs,
1256                                 unsigned long offset,
1257                                 unsigned long delta_size,
1258                                 enum object_type kind,
1259                                 unsigned long obj_offset,
1260                                 char *type,
1261                                 unsigned long *sizep)
1262 {
1263         void *delta_data, *result, *base;
1264         unsigned long result_size, base_size, base_offset;
1265
1266         offset = get_delta_base(p, w_curs, offset, kind,
1267                 obj_offset, &base_offset);
1268         base = unpack_entry(p, base_offset, type, &base_size);
1269         if (!base)
1270                 die("failed to read delta base object at %lu from %s",
1271                     base_offset, p->pack_name);
1272
1273         delta_data = unpack_compressed_entry(p, w_curs, offset, delta_size);
1274         result = patch_delta(base, base_size,
1275                              delta_data, delta_size,
1276                              &result_size);
1277         if (!result)
1278                 die("failed to apply delta");
1279         free(delta_data);
1280         free(base);
1281         *sizep = result_size;
1282         return result;
1283 }
1284
1285 void *unpack_entry(struct packed_git *p, unsigned long offset,
1286                           char *type, unsigned long *sizep)
1287 {
1288         struct pack_window *w_curs = NULL;
1289         unsigned long size, obj_offset = offset;
1290         enum object_type kind;
1291         void *retval;
1292
1293         offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
1294         switch (kind) {
1295         case OBJ_OFS_DELTA:
1296         case OBJ_REF_DELTA:
1297                 retval = unpack_delta_entry(p, &w_curs, offset, size,
1298                         kind, obj_offset, type, sizep);
1299                 break;
1300         case OBJ_COMMIT:
1301         case OBJ_TREE:
1302         case OBJ_BLOB:
1303         case OBJ_TAG:
1304                 strcpy(type, type_names[kind]);
1305                 *sizep = size;
1306                 retval = unpack_compressed_entry(p, &w_curs, offset, size);
1307                 break;
1308         default:
1309                 die("unknown object type %i in %s", kind, p->pack_name);
1310         }
1311         unuse_pack(&w_curs);
1312         return retval;
1313 }
1314
1315 int num_packed_objects(const struct packed_git *p)
1316 {
1317         /* See check_packed_git_idx() */
1318         return (p->index_size - 20 - 20 - 4*256) / 24;
1319 }
1320
1321 int nth_packed_object_sha1(const struct packed_git *p, int n,
1322                            unsigned char* sha1)
1323 {
1324         void *index = p->index_base + 256;
1325         if (n < 0 || num_packed_objects(p) <= n)
1326                 return -1;
1327         hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
1328         return 0;
1329 }
1330
1331 unsigned long find_pack_entry_one(const unsigned char *sha1,
1332                                   struct packed_git *p)
1333 {
1334         unsigned int *level1_ofs = p->index_base;
1335         int hi = ntohl(level1_ofs[*sha1]);
1336         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1337         void *index = p->index_base + 256;
1338
1339         do {
1340                 int mi = (lo + hi) / 2;
1341                 int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
1342                 if (!cmp)
1343                         return ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
1344                 if (cmp > 0)
1345                         hi = mi;
1346                 else
1347                         lo = mi+1;
1348         } while (lo < hi);
1349         return 0;
1350 }
1351
1352 static int matches_pack_name(struct packed_git *p, const char *ig)
1353 {
1354         const char *last_c, *c;
1355
1356         if (!strcmp(p->pack_name, ig))
1357                 return 0;
1358
1359         for (c = p->pack_name, last_c = c; *c;)
1360                 if (*c == '/')
1361                         last_c = ++c;
1362                 else
1363                         ++c;
1364         if (!strcmp(last_c, ig))
1365                 return 0;
1366
1367         return 1;
1368 }
1369
1370 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
1371 {
1372         struct packed_git *p;
1373         unsigned long offset;
1374
1375         prepare_packed_git();
1376
1377         for (p = packed_git; p; p = p->next) {
1378                 if (ignore_packed) {
1379                         const char **ig;
1380                         for (ig = ignore_packed; *ig; ig++)
1381                                 if (!matches_pack_name(p, *ig))
1382                                         break;
1383                         if (*ig)
1384                                 continue;
1385                 }
1386                 offset = find_pack_entry_one(sha1, p);
1387                 if (offset) {
1388                         e->offset = offset;
1389                         e->p = p;
1390                         hashcpy(e->sha1, sha1);
1391                         return 1;
1392                 }
1393         }
1394         return 0;
1395 }
1396
1397 struct packed_git *find_sha1_pack(const unsigned char *sha1, 
1398                                   struct packed_git *packs)
1399 {
1400         struct packed_git *p;
1401
1402         for (p = packs; p; p = p->next) {
1403                 if (find_pack_entry_one(sha1, p))
1404                         return p;
1405         }
1406         return NULL;
1407         
1408 }
1409
1410 static int sha1_loose_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1411 {
1412         int status;
1413         unsigned long mapsize, size;
1414         void *map;
1415         z_stream stream;
1416         char hdr[128];
1417
1418         map = map_sha1_file(sha1, &mapsize);
1419         if (!map)
1420                 return error("unable to find %s", sha1_to_hex(sha1));
1421         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1422                 status = error("unable to unpack %s header",
1423                                sha1_to_hex(sha1));
1424         if (parse_sha1_header(hdr, type, &size) < 0)
1425                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1426         else {
1427                 status = 0;
1428                 if (sizep)
1429                         *sizep = size;
1430         }
1431         inflateEnd(&stream);
1432         munmap(map, mapsize);
1433         return status;
1434 }
1435
1436 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1437 {
1438         struct pack_entry e;
1439
1440         if (!find_pack_entry(sha1, &e, NULL)) {
1441                 reprepare_packed_git();
1442                 if (!find_pack_entry(sha1, &e, NULL))
1443                         return sha1_loose_object_info(sha1, type, sizep);
1444         }
1445         return packed_object_info(e.p, e.offset, type, sizep);
1446 }
1447
1448 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1449 {
1450         struct pack_entry e;
1451
1452         if (!find_pack_entry(sha1, &e, NULL)) {
1453                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1454                 return NULL;
1455         }
1456         return unpack_entry(e.p, e.offset, type, size);
1457 }
1458
1459 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1460 {
1461         unsigned long mapsize;
1462         void *map, *buf;
1463         struct pack_entry e;
1464
1465         if (find_pack_entry(sha1, &e, NULL))
1466                 return read_packed_sha1(sha1, type, size);
1467         map = map_sha1_file(sha1, &mapsize);
1468         if (map) {
1469                 buf = unpack_sha1_file(map, mapsize, type, size);
1470                 munmap(map, mapsize);
1471                 return buf;
1472         }
1473         reprepare_packed_git();
1474         if (find_pack_entry(sha1, &e, NULL))
1475                 return read_packed_sha1(sha1, type, size);
1476         return NULL;
1477 }
1478
1479 void *read_object_with_reference(const unsigned char *sha1,
1480                                  const char *required_type,
1481                                  unsigned long *size,
1482                                  unsigned char *actual_sha1_return)
1483 {
1484         char type[20];
1485         void *buffer;
1486         unsigned long isize;
1487         unsigned char actual_sha1[20];
1488
1489         hashcpy(actual_sha1, sha1);
1490         while (1) {
1491                 int ref_length = -1;
1492                 const char *ref_type = NULL;
1493
1494                 buffer = read_sha1_file(actual_sha1, type, &isize);
1495                 if (!buffer)
1496                         return NULL;
1497                 if (!strcmp(type, required_type)) {
1498                         *size = isize;
1499                         if (actual_sha1_return)
1500                                 hashcpy(actual_sha1_return, actual_sha1);
1501                         return buffer;
1502                 }
1503                 /* Handle references */
1504                 else if (!strcmp(type, commit_type))
1505                         ref_type = "tree ";
1506                 else if (!strcmp(type, tag_type))
1507                         ref_type = "object ";
1508                 else {
1509                         free(buffer);
1510                         return NULL;
1511                 }
1512                 ref_length = strlen(ref_type);
1513
1514                 if (memcmp(buffer, ref_type, ref_length) ||
1515                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1516                         free(buffer);
1517                         return NULL;
1518                 }
1519                 free(buffer);
1520                 /* Now we have the ID of the referred-to object in
1521                  * actual_sha1.  Check again. */
1522         }
1523 }
1524
1525 static void write_sha1_file_prepare(void *buf, unsigned long len,
1526                                     const char *type, unsigned char *sha1,
1527                                     unsigned char *hdr, int *hdrlen)
1528 {
1529         SHA_CTX c;
1530
1531         /* Generate the header */
1532         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1533
1534         /* Sha1.. */
1535         SHA1_Init(&c);
1536         SHA1_Update(&c, hdr, *hdrlen);
1537         SHA1_Update(&c, buf, len);
1538         SHA1_Final(sha1, &c);
1539 }
1540
1541 /*
1542  * Link the tempfile to the final place, possibly creating the
1543  * last directory level as you do so.
1544  *
1545  * Returns the errno on failure, 0 on success.
1546  */
1547 static int link_temp_to_file(const char *tmpfile, const char *filename)
1548 {
1549         int ret;
1550         char *dir;
1551
1552         if (!link(tmpfile, filename))
1553                 return 0;
1554
1555         /*
1556          * Try to mkdir the last path component if that failed.
1557          *
1558          * Re-try the "link()" regardless of whether the mkdir
1559          * succeeds, since a race might mean that somebody
1560          * else succeeded.
1561          */
1562         ret = errno;
1563         dir = strrchr(filename, '/');
1564         if (dir) {
1565                 *dir = 0;
1566                 if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
1567                         *dir = '/';
1568                         return -2;
1569                 }
1570                 *dir = '/';
1571                 if (!link(tmpfile, filename))
1572                         return 0;
1573                 ret = errno;
1574         }
1575         return ret;
1576 }
1577
1578 /*
1579  * Move the just written object into its final resting place
1580  */
1581 int move_temp_to_file(const char *tmpfile, const char *filename)
1582 {
1583         int ret = link_temp_to_file(tmpfile, filename);
1584
1585         /*
1586          * Coda hack - coda doesn't like cross-directory links,
1587          * so we fall back to a rename, which will mean that it
1588          * won't be able to check collisions, but that's not a
1589          * big deal.
1590          *
1591          * The same holds for FAT formatted media.
1592          *
1593          * When this succeeds, we just return 0. We have nothing
1594          * left to unlink.
1595          */
1596         if (ret && ret != EEXIST) {
1597                 if (!rename(tmpfile, filename))
1598                         return 0;
1599                 ret = errno;
1600         }
1601         unlink(tmpfile);
1602         if (ret) {
1603                 if (ret != EEXIST) {
1604                         return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1605                 }
1606                 /* FIXME!!! Collision check here ? */
1607         }
1608
1609         return 0;
1610 }
1611
1612 static int write_buffer(int fd, const void *buf, size_t len)
1613 {
1614         ssize_t size;
1615
1616         size = write_in_full(fd, buf, len);
1617         if (!size)
1618                 return error("file write: disk full");
1619         if (size < 0)
1620                 return error("file write error (%s)", strerror(errno));
1621         return 0;
1622 }
1623
1624 static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1625 {
1626         int hdr_len;
1627         unsigned char c;
1628
1629         c = (type << 4) | (len & 15);
1630         len >>= 4;
1631         hdr_len = 1;
1632         while (len) {
1633                 *hdr++ = c | 0x80;
1634                 hdr_len++;
1635                 c = (len & 0x7f);
1636                 len >>= 7;
1637         }
1638         *hdr = c;
1639         return hdr_len;
1640 }
1641
1642 static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1643 {
1644         int obj_type, hdr;
1645
1646         if (use_legacy_headers) {
1647                 while (deflate(stream, 0) == Z_OK)
1648                         /* nothing */;
1649                 return;
1650         }
1651         if (!strcmp(type, blob_type))
1652                 obj_type = OBJ_BLOB;
1653         else if (!strcmp(type, tree_type))
1654                 obj_type = OBJ_TREE;
1655         else if (!strcmp(type, commit_type))
1656                 obj_type = OBJ_COMMIT;
1657         else if (!strcmp(type, tag_type))
1658                 obj_type = OBJ_TAG;
1659         else
1660                 die("trying to generate bogus object of type '%s'", type);
1661         hdr = write_binary_header(stream->next_out, obj_type, len);
1662         stream->total_out = hdr;
1663         stream->next_out += hdr;
1664         stream->avail_out -= hdr;
1665 }
1666
1667 int hash_sha1_file(void *buf, unsigned long len, const char *type,
1668                    unsigned char *sha1)
1669 {
1670         unsigned char hdr[50];
1671         int hdrlen;
1672         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1673         return 0;
1674 }
1675
1676 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1677 {
1678         int size;
1679         unsigned char *compressed;
1680         z_stream stream;
1681         unsigned char sha1[20];
1682         char *filename;
1683         static char tmpfile[PATH_MAX];
1684         unsigned char hdr[50];
1685         int fd, hdrlen;
1686
1687         /* Normally if we have it in the pack then we do not bother writing
1688          * it out into .git/objects/??/?{38} file.
1689          */
1690         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1691         filename = sha1_file_name(sha1);
1692         if (returnsha1)
1693                 hashcpy(returnsha1, sha1);
1694         if (has_sha1_file(sha1))
1695                 return 0;
1696         fd = open(filename, O_RDONLY);
1697         if (fd >= 0) {
1698                 /*
1699                  * FIXME!!! We might do collision checking here, but we'd
1700                  * need to uncompress the old file and check it. Later.
1701                  */
1702                 close(fd);
1703                 return 0;
1704         }
1705
1706         if (errno != ENOENT) {
1707                 return error("sha1 file %s: %s\n", filename, strerror(errno));
1708         }
1709
1710         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1711
1712         fd = mkstemp(tmpfile);
1713         if (fd < 0) {
1714                 if (errno == EPERM)
1715                         return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1716                 else
1717                         return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1718         }
1719
1720         /* Set it up */
1721         memset(&stream, 0, sizeof(stream));
1722         deflateInit(&stream, zlib_compression_level);
1723         size = 8 + deflateBound(&stream, len+hdrlen);
1724         compressed = xmalloc(size);
1725
1726         /* Compress it */
1727         stream.next_out = compressed;
1728         stream.avail_out = size;
1729
1730         /* First header.. */
1731         stream.next_in = hdr;
1732         stream.avail_in = hdrlen;
1733         setup_object_header(&stream, type, len);
1734
1735         /* Then the data itself.. */
1736         stream.next_in = buf;
1737         stream.avail_in = len;
1738         while (deflate(&stream, Z_FINISH) == Z_OK)
1739                 /* nothing */;
1740         deflateEnd(&stream);
1741         size = stream.total_out;
1742
1743         if (write_buffer(fd, compressed, size) < 0)
1744                 die("unable to write sha1 file");
1745         fchmod(fd, 0444);
1746         close(fd);
1747         free(compressed);
1748
1749         return move_temp_to_file(tmpfile, filename);
1750 }
1751
1752 /*
1753  * We need to unpack and recompress the object for writing
1754  * it out to a different file.
1755  */
1756 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1757 {
1758         size_t size;
1759         z_stream stream;
1760         unsigned char *unpacked;
1761         unsigned long len;
1762         char type[20];
1763         char hdr[50];
1764         int hdrlen;
1765         void *buf;
1766
1767         /* need to unpack and recompress it by itself */
1768         unpacked = read_packed_sha1(sha1, type, &len);
1769
1770         hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1771
1772         /* Set it up */
1773         memset(&stream, 0, sizeof(stream));
1774         deflateInit(&stream, zlib_compression_level);
1775         size = deflateBound(&stream, len + hdrlen);
1776         buf = xmalloc(size);
1777
1778         /* Compress it */
1779         stream.next_out = buf;
1780         stream.avail_out = size;
1781
1782         /* First header.. */
1783         stream.next_in = (void *)hdr;
1784         stream.avail_in = hdrlen;
1785         while (deflate(&stream, 0) == Z_OK)
1786                 /* nothing */;
1787
1788         /* Then the data itself.. */
1789         stream.next_in = unpacked;
1790         stream.avail_in = len;
1791         while (deflate(&stream, Z_FINISH) == Z_OK)
1792                 /* nothing */;
1793         deflateEnd(&stream);
1794         free(unpacked);
1795
1796         *objsize = stream.total_out;
1797         return buf;
1798 }
1799
1800 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1801 {
1802         int retval;
1803         unsigned long objsize;
1804         void *buf = map_sha1_file(sha1, &objsize);
1805
1806         if (buf) {
1807                 retval = write_buffer(fd, buf, objsize);
1808                 munmap(buf, objsize);
1809                 return retval;
1810         }
1811
1812         buf = repack_object(sha1, &objsize);
1813         retval = write_buffer(fd, buf, objsize);
1814         free(buf);
1815         return retval;
1816 }
1817
1818 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1819                        size_t bufsize, size_t *bufposn)
1820 {
1821         char tmpfile[PATH_MAX];
1822         int local;
1823         z_stream stream;
1824         unsigned char real_sha1[20];
1825         unsigned char discard[4096];
1826         int ret;
1827         SHA_CTX c;
1828
1829         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1830
1831         local = mkstemp(tmpfile);
1832         if (local < 0) {
1833                 if (errno == EPERM)
1834                         return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1835                 else
1836                         return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1837         }
1838
1839         memset(&stream, 0, sizeof(stream));
1840
1841         inflateInit(&stream);
1842
1843         SHA1_Init(&c);
1844
1845         do {
1846                 ssize_t size;
1847                 if (*bufposn) {
1848                         stream.avail_in = *bufposn;
1849                         stream.next_in = (unsigned char *) buffer;
1850                         do {
1851                                 stream.next_out = discard;
1852                                 stream.avail_out = sizeof(discard);
1853                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1854                                 SHA1_Update(&c, discard, sizeof(discard) -
1855                                             stream.avail_out);
1856                         } while (stream.avail_in && ret == Z_OK);
1857                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1858                                 die("unable to write sha1 file");
1859                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1860                                 stream.avail_in);
1861                         *bufposn = stream.avail_in;
1862                         if (ret != Z_OK)
1863                                 break;
1864                 }
1865                 size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
1866                 if (size <= 0) {
1867                         close(local);
1868                         unlink(tmpfile);
1869                         if (!size)
1870                                 return error("Connection closed?");
1871                         perror("Reading from connection");
1872                         return -1;
1873                 }
1874                 *bufposn += size;
1875         } while (1);
1876         inflateEnd(&stream);
1877
1878         close(local);
1879         SHA1_Final(real_sha1, &c);
1880         if (ret != Z_STREAM_END) {
1881                 unlink(tmpfile);
1882                 return error("File %s corrupted", sha1_to_hex(sha1));
1883         }
1884         if (hashcmp(sha1, real_sha1)) {
1885                 unlink(tmpfile);
1886                 return error("File %s has bad hash", sha1_to_hex(sha1));
1887         }
1888
1889         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1890 }
1891
1892 int has_pack_index(const unsigned char *sha1)
1893 {
1894         struct stat st;
1895         if (stat(sha1_pack_index_name(sha1), &st))
1896                 return 0;
1897         return 1;
1898 }
1899
1900 int has_pack_file(const unsigned char *sha1)
1901 {
1902         struct stat st;
1903         if (stat(sha1_pack_name(sha1), &st))
1904                 return 0;
1905         return 1;
1906 }
1907
1908 int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
1909 {
1910         struct pack_entry e;
1911         return find_pack_entry(sha1, &e, ignore_packed);
1912 }
1913
1914 int has_sha1_file(const unsigned char *sha1)
1915 {
1916         struct stat st;
1917         struct pack_entry e;
1918
1919         if (find_pack_entry(sha1, &e, NULL))
1920                 return 1;
1921         return find_sha1_file(sha1, &st) ? 1 : 0;
1922 }
1923
1924 /*
1925  * reads from fd as long as possible into a supplied buffer of size bytes.
1926  * If necessary the buffer's size is increased using realloc()
1927  *
1928  * returns 0 if anything went fine and -1 otherwise
1929  *
1930  * NOTE: both buf and size may change, but even when -1 is returned
1931  * you still have to free() it yourself.
1932  */
1933 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1934 {
1935         char* buf = *return_buf;
1936         unsigned long size = *return_size;
1937         int iret;
1938         unsigned long off = 0;
1939
1940         do {
1941                 iret = xread(fd, buf + off, size - off);
1942                 if (iret > 0) {
1943                         off += iret;
1944                         if (off == size) {
1945                                 size *= 2;
1946                                 buf = xrealloc(buf, size);
1947                         }
1948                 }
1949         } while (iret > 0);
1950
1951         *return_buf = buf;
1952         *return_size = off;
1953
1954         if (iret < 0)
1955                 return -1;
1956         return 0;
1957 }
1958
1959 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1960 {
1961         unsigned long size = 4096;
1962         char *buf = xmalloc(size);
1963         int ret;
1964
1965         if (read_pipe(fd, &buf, &size)) {
1966                 free(buf);
1967                 return -1;
1968         }
1969
1970         if (!type)
1971                 type = blob_type;
1972         if (write_object)
1973                 ret = write_sha1_file(buf, size, type, sha1);
1974         else
1975                 ret = hash_sha1_file(buf, size, type, sha1);
1976         free(buf);
1977         return ret;
1978 }
1979
1980 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1981 {
1982         unsigned long size = st->st_size;
1983         void *buf;
1984         int ret;
1985
1986         buf = "";
1987         if (size)
1988                 buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1989         close(fd);
1990
1991         if (!type)
1992                 type = blob_type;
1993         if (write_object)
1994                 ret = write_sha1_file(buf, size, type, sha1);
1995         else
1996                 ret = hash_sha1_file(buf, size, type, sha1);
1997         if (size)
1998                 munmap(buf, size);
1999         return ret;
2000 }
2001
2002 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
2003 {
2004         int fd;
2005         char *target;
2006
2007         switch (st->st_mode & S_IFMT) {
2008         case S_IFREG:
2009                 fd = open(path, O_RDONLY);
2010                 if (fd < 0)
2011                         return error("open(\"%s\"): %s", path,
2012                                      strerror(errno));
2013                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
2014                         return error("%s: failed to insert into database",
2015                                      path);
2016                 break;
2017         case S_IFLNK:
2018                 target = xmalloc(st->st_size+1);
2019                 if (readlink(path, target, st->st_size+1) != st->st_size) {
2020                         char *errstr = strerror(errno);
2021                         free(target);
2022                         return error("readlink(\"%s\"): %s", path,
2023                                      errstr);
2024                 }
2025                 if (!write_object)
2026                         hash_sha1_file(target, st->st_size, blob_type, sha1);
2027                 else if (write_sha1_file(target, st->st_size, blob_type, sha1))
2028                         return error("%s: failed to insert into database",
2029                                      path);
2030                 free(target);
2031                 break;
2032         default:
2033                 return error("%s: unsupported file type", path);
2034         }
2035         return 0;
2036 }