gitweb: safely output binary files for 'blob_plain' action
[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] = { 0, };
26
27 static unsigned int sha1_file_open_flag = O_NOATIME;
28
29 static unsigned hexval(char c)
30 {
31         if (c >= '0' && c <= '9')
32                 return c - '0';
33         if (c >= 'a' && c <= 'f')
34                 return c - 'a' + 10;
35         if (c >= 'A' && c <= 'F')
36                 return c - 'A' + 10;
37         return ~0;
38 }
39
40 int get_sha1_hex(const char *hex, unsigned char *sha1)
41 {
42         int i;
43         for (i = 0; i < 20; i++) {
44                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
45                 if (val & ~0xff)
46                         return -1;
47                 *sha1++ = val;
48                 hex += 2;
49         }
50         return 0;
51 }
52
53 int safe_create_leading_directories(char *path)
54 {
55         char *pos = path;
56         struct stat st;
57
58         if (*pos == '/')
59                 pos++;
60
61         while (pos) {
62                 pos = strchr(pos, '/');
63                 if (!pos)
64                         break;
65                 *pos = 0;
66                 if (!stat(path, &st)) {
67                         /* path exists */
68                         if (!S_ISDIR(st.st_mode)) {
69                                 *pos = '/';
70                                 return -3;
71                         }
72                 }
73                 else if (mkdir(path, 0777)) {
74                         *pos = '/';
75                         return -1;
76                 }
77                 else if (adjust_shared_perm(path)) {
78                         *pos = '/';
79                         return -2;
80                 }
81                 *pos++ = '/';
82         }
83         return 0;
84 }
85
86 char * sha1_to_hex(const unsigned char *sha1)
87 {
88         static int bufno;
89         static char hexbuffer[4][50];
90         static const char hex[] = "0123456789abcdef";
91         char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
92         int i;
93
94         for (i = 0; i < 20; i++) {
95                 unsigned int val = *sha1++;
96                 *buf++ = hex[val >> 4];
97                 *buf++ = hex[val & 0xf];
98         }
99         *buf = '\0';
100
101         return buffer;
102 }
103
104 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
105 {
106         int i;
107         for (i = 0; i < 20; i++) {
108                 static char hex[] = "0123456789abcdef";
109                 unsigned int val = sha1[i];
110                 char *pos = pathbuf + i*2 + (i > 0);
111                 *pos++ = hex[val >> 4];
112                 *pos = hex[val & 0xf];
113         }
114 }
115
116 /*
117  * NOTE! This returns a statically allocated buffer, so you have to be
118  * careful about using it. Do a "strdup()" if you need to save the
119  * filename.
120  *
121  * Also note that this returns the location for creating.  Reading
122  * SHA1 file can happen from any alternate directory listed in the
123  * DB_ENVIRONMENT environment variable if it is not found in
124  * the primary object database.
125  */
126 char *sha1_file_name(const unsigned char *sha1)
127 {
128         static char *name, *base;
129
130         if (!base) {
131                 const char *sha1_file_directory = get_object_directory();
132                 int len = strlen(sha1_file_directory);
133                 base = xmalloc(len + 60);
134                 memcpy(base, sha1_file_directory, len);
135                 memset(base+len, 0, 60);
136                 base[len] = '/';
137                 base[len+3] = '/';
138                 name = base + len + 1;
139         }
140         fill_sha1_path(name, sha1);
141         return base;
142 }
143
144 char *sha1_pack_name(const unsigned char *sha1)
145 {
146         static const char hex[] = "0123456789abcdef";
147         static char *name, *base, *buf;
148         int i;
149
150         if (!base) {
151                 const char *sha1_file_directory = get_object_directory();
152                 int len = strlen(sha1_file_directory);
153                 base = xmalloc(len + 60);
154                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
155                 name = base + len + 11;
156         }
157
158         buf = name;
159
160         for (i = 0; i < 20; i++) {
161                 unsigned int val = *sha1++;
162                 *buf++ = hex[val >> 4];
163                 *buf++ = hex[val & 0xf];
164         }
165         
166         return base;
167 }
168
169 char *sha1_pack_index_name(const unsigned char *sha1)
170 {
171         static const char hex[] = "0123456789abcdef";
172         static char *name, *base, *buf;
173         int i;
174
175         if (!base) {
176                 const char *sha1_file_directory = get_object_directory();
177                 int len = strlen(sha1_file_directory);
178                 base = xmalloc(len + 60);
179                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
180                 name = base + len + 11;
181         }
182
183         buf = name;
184
185         for (i = 0; i < 20; i++) {
186                 unsigned int val = *sha1++;
187                 *buf++ = hex[val >> 4];
188                 *buf++ = hex[val & 0xf];
189         }
190         
191         return base;
192 }
193
194 struct alternate_object_database *alt_odb_list;
195 static struct alternate_object_database **alt_odb_tail;
196
197 static void read_info_alternates(const char * alternates, int depth);
198
199 /*
200  * Prepare alternate object database registry.
201  *
202  * The variable alt_odb_list points at the list of struct
203  * alternate_object_database.  The elements on this list come from
204  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
205  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
206  * whose contents is similar to that environment variable but can be
207  * LF separated.  Its base points at a statically allocated buffer that
208  * contains "/the/directory/corresponding/to/.git/objects/...", while
209  * its name points just after the slash at the end of ".git/objects/"
210  * in the example above, and has enough space to hold 40-byte hex
211  * SHA1, an extra slash for the first level indirection, and the
212  * terminating NUL.
213  */
214 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
215 {
216         struct stat st;
217         const char *objdir = get_object_directory();
218         struct alternate_object_database *ent;
219         struct alternate_object_database *alt;
220         /* 43 = 40-byte + 2 '/' + terminating NUL */
221         int pfxlen = len;
222         int entlen = pfxlen + 43;
223         int base_len = -1;
224
225         if (*entry != '/' && relative_base) {
226                 /* Relative alt-odb */
227                 if (base_len < 0)
228                         base_len = strlen(relative_base) + 1;
229                 entlen += base_len;
230                 pfxlen += base_len;
231         }
232         ent = xmalloc(sizeof(*ent) + entlen);
233
234         if (*entry != '/' && relative_base) {
235                 memcpy(ent->base, relative_base, base_len - 1);
236                 ent->base[base_len - 1] = '/';
237                 memcpy(ent->base + base_len, entry, len);
238         }
239         else
240                 memcpy(ent->base, entry, pfxlen);
241
242         ent->name = ent->base + pfxlen + 1;
243         ent->base[pfxlen + 3] = '/';
244         ent->base[pfxlen] = ent->base[entlen-1] = 0;
245
246         /* Detect cases where alternate disappeared */
247         if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
248                 error("object directory %s does not exist; "
249                       "check .git/objects/info/alternates.",
250                       ent->base);
251                 free(ent);
252                 return -1;
253         }
254
255         /* Prevent the common mistake of listing the same
256          * thing twice, or object directory itself.
257          */
258         for (alt = alt_odb_list; alt; alt = alt->next) {
259                 if (!memcmp(ent->base, alt->base, pfxlen)) {
260                         free(ent);
261                         return -1;
262                 }
263         }
264         if (!memcmp(ent->base, objdir, pfxlen)) {
265                 free(ent);
266                 return -1;
267         }
268
269         /* add the alternate entry */
270         *alt_odb_tail = ent;
271         alt_odb_tail = &(ent->next);
272         ent->next = NULL;
273
274         /* recursively add alternates */
275         read_info_alternates(ent->base, depth + 1);
276
277         ent->base[pfxlen] = '/';
278
279         return 0;
280 }
281
282 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
283                                  const char *relative_base, int depth)
284 {
285         const char *cp, *last;
286
287         if (depth > 5) {
288                 error("%s: ignoring alternate object stores, nesting too deep.",
289                                 relative_base);
290                 return;
291         }
292
293         last = alt;
294         while (last < ep) {
295                 cp = last;
296                 if (cp < ep && *cp == '#') {
297                         while (cp < ep && *cp != sep)
298                                 cp++;
299                         last = cp + 1;
300                         continue;
301                 }
302                 while (cp < ep && *cp != sep)
303                         cp++;
304                 if (last != cp) {
305                         if ((*last != '/') && depth) {
306                                 error("%s: ignoring relative alternate object store %s",
307                                                 relative_base, last);
308                         } else {
309                                 link_alt_odb_entry(last, cp - last,
310                                                 relative_base, depth);
311                         }
312                 }
313                 while (cp < ep && *cp == sep)
314                         cp++;
315                 last = cp;
316         }
317 }
318
319 static void read_info_alternates(const char * relative_base, int depth)
320 {
321         char *map;
322         struct stat st;
323         char path[PATH_MAX];
324         int fd;
325
326         sprintf(path, "%s/info/alternates", relative_base);
327         fd = open(path, O_RDONLY);
328         if (fd < 0)
329                 return;
330         if (fstat(fd, &st) || (st.st_size == 0)) {
331                 close(fd);
332                 return;
333         }
334         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
335         close(fd);
336         if (map == MAP_FAILED)
337                 return;
338
339         link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
340
341         munmap(map, st.st_size);
342 }
343
344 void prepare_alt_odb(void)
345 {
346         char *alt;
347
348         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
349         if (!alt) alt = "";
350
351         if (alt_odb_tail)
352                 return;
353         alt_odb_tail = &alt_odb_list;
354         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
355
356         read_info_alternates(get_object_directory(), 0);
357 }
358
359 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
360 {
361         char *name = sha1_file_name(sha1);
362         struct alternate_object_database *alt;
363
364         if (!stat(name, st))
365                 return name;
366         prepare_alt_odb();
367         for (alt = alt_odb_list; alt; alt = alt->next) {
368                 name = alt->name;
369                 fill_sha1_path(name, sha1);
370                 if (!stat(alt->base, st))
371                         return alt->base;
372         }
373         return NULL;
374 }
375
376 #define PACK_MAX_SZ (1<<26)
377 static int pack_used_ctr;
378 static unsigned long pack_mapped;
379 struct packed_git *packed_git;
380
381 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
382                                 void **idx_map_)
383 {
384         void *idx_map;
385         unsigned int *index;
386         unsigned long idx_size;
387         int nr, i;
388         int fd = open(path, O_RDONLY);
389         struct stat st;
390         if (fd < 0)
391                 return -1;
392         if (fstat(fd, &st)) {
393                 close(fd);
394                 return -1;
395         }
396         idx_size = st.st_size;
397         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
398         close(fd);
399         if (idx_map == MAP_FAILED)
400                 return -1;
401
402         index = idx_map;
403         *idx_map_ = idx_map;
404         *idx_size_ = idx_size;
405
406         /* check index map */
407         if (idx_size < 4*256 + 20 + 20)
408                 return error("index file too small");
409         nr = 0;
410         for (i = 0; i < 256; i++) {
411                 unsigned int n = ntohl(index[i]);
412                 if (n < nr)
413                         return error("non-monotonic index");
414                 nr = n;
415         }
416
417         /*
418          * Total size:
419          *  - 256 index entries 4 bytes each
420          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
421          *  - 20-byte SHA1 of the packfile
422          *  - 20-byte SHA1 file checksum
423          */
424         if (idx_size != 4*256 + nr * 24 + 20 + 20)
425                 return error("wrong index file size");
426
427         return 0;
428 }
429
430 static int unuse_one_packed_git(void)
431 {
432         struct packed_git *p, *lru = NULL;
433
434         for (p = packed_git; p; p = p->next) {
435                 if (p->pack_use_cnt || !p->pack_base)
436                         continue;
437                 if (!lru || p->pack_last_used < lru->pack_last_used)
438                         lru = p;
439         }
440         if (!lru)
441                 return 0;
442         munmap(lru->pack_base, lru->pack_size);
443         lru->pack_base = NULL;
444         return 1;
445 }
446
447 void unuse_packed_git(struct packed_git *p)
448 {
449         p->pack_use_cnt--;
450 }
451
452 int use_packed_git(struct packed_git *p)
453 {
454         if (!p->pack_size) {
455                 struct stat st;
456                 // We created the struct before we had the pack
457                 stat(p->pack_name, &st);
458                 if (!S_ISREG(st.st_mode))
459                         die("packfile %s not a regular file", p->pack_name);
460                 p->pack_size = st.st_size;
461         }
462         if (!p->pack_base) {
463                 int fd;
464                 struct stat st;
465                 void *map;
466
467                 pack_mapped += p->pack_size;
468                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
469                         ; /* nothing */
470                 fd = open(p->pack_name, O_RDONLY);
471                 if (fd < 0)
472                         die("packfile %s cannot be opened", p->pack_name);
473                 if (fstat(fd, &st)) {
474                         close(fd);
475                         die("packfile %s cannot be opened", p->pack_name);
476                 }
477                 if (st.st_size != p->pack_size)
478                         die("packfile %s size mismatch.", p->pack_name);
479                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
480                 close(fd);
481                 if (map == MAP_FAILED)
482                         die("packfile %s cannot be mapped.", p->pack_name);
483                 p->pack_base = map;
484
485                 /* Check if the pack file matches with the index file.
486                  * this is cheap.
487                  */
488                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
489                            p->pack_base + p->pack_size - 20, 20)) {
490                               
491                         die("packfile %s does not match index.", p->pack_name);
492                 }
493         }
494         p->pack_last_used = pack_used_ctr++;
495         p->pack_use_cnt++;
496         return 0;
497 }
498
499 struct packed_git *add_packed_git(char *path, int path_len, int local)
500 {
501         struct stat st;
502         struct packed_git *p;
503         unsigned long idx_size;
504         void *idx_map;
505         unsigned char sha1[20];
506
507         if (check_packed_git_idx(path, &idx_size, &idx_map))
508                 return NULL;
509
510         /* do we have a corresponding .pack file? */
511         strcpy(path + path_len - 4, ".pack");
512         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
513                 munmap(idx_map, idx_size);
514                 return NULL;
515         }
516         /* ok, it looks sane as far as we can check without
517          * actually mapping the pack file.
518          */
519         p = xmalloc(sizeof(*p) + path_len + 2);
520         strcpy(p->pack_name, path);
521         p->index_size = idx_size;
522         p->pack_size = st.st_size;
523         p->index_base = idx_map;
524         p->next = NULL;
525         p->pack_base = NULL;
526         p->pack_last_used = 0;
527         p->pack_use_cnt = 0;
528         p->pack_local = local;
529         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
530                 memcpy(p->sha1, sha1, 20);
531         return p;
532 }
533
534 struct packed_git *parse_pack_index(unsigned char *sha1)
535 {
536         char *path = sha1_pack_index_name(sha1);
537         return parse_pack_index_file(sha1, path);
538 }
539
540 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
541 {
542         struct packed_git *p;
543         unsigned long idx_size;
544         void *idx_map;
545         char *path;
546
547         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
548                 return NULL;
549
550         path = sha1_pack_name(sha1);
551
552         p = xmalloc(sizeof(*p) + strlen(path) + 2);
553         strcpy(p->pack_name, path);
554         p->index_size = idx_size;
555         p->pack_size = 0;
556         p->index_base = idx_map;
557         p->next = NULL;
558         p->pack_base = NULL;
559         p->pack_last_used = 0;
560         p->pack_use_cnt = 0;
561         memcpy(p->sha1, sha1, 20);
562         return p;
563 }
564
565 void install_packed_git(struct packed_git *pack)
566 {
567         pack->next = packed_git;
568         packed_git = pack;
569 }
570
571 static void prepare_packed_git_one(char *objdir, int local)
572 {
573         char path[PATH_MAX];
574         int len;
575         DIR *dir;
576         struct dirent *de;
577
578         sprintf(path, "%s/pack", objdir);
579         len = strlen(path);
580         dir = opendir(path);
581         if (!dir) {
582                 if (errno != ENOENT)
583                         error("unable to open object pack directory: %s: %s",
584                               path, strerror(errno));
585                 return;
586         }
587         path[len++] = '/';
588         while ((de = readdir(dir)) != NULL) {
589                 int namelen = strlen(de->d_name);
590                 struct packed_git *p;
591
592                 if (strcmp(de->d_name + namelen - 4, ".idx"))
593                         continue;
594
595                 /* we have .idx.  Is it a file we can map? */
596                 strcpy(path + len, de->d_name);
597                 for (p = packed_git; p; p = p->next) {
598                         if (!memcmp(path, p->pack_name, len + namelen - 4))
599                                 break;
600                 }
601                 if (p)
602                         continue;
603                 p = add_packed_git(path, len + namelen, local);
604                 if (!p)
605                         continue;
606                 p->next = packed_git;
607                 packed_git = p;
608         }
609         closedir(dir);
610 }
611
612 static int prepare_packed_git_run_once = 0;
613 void prepare_packed_git(void)
614 {
615         struct alternate_object_database *alt;
616
617         if (prepare_packed_git_run_once)
618                 return;
619         prepare_packed_git_one(get_object_directory(), 1);
620         prepare_alt_odb();
621         for (alt = alt_odb_list; alt; alt = alt->next) {
622                 alt->name[-1] = 0;
623                 prepare_packed_git_one(alt->base, 0);
624                 alt->name[-1] = '/';
625         }
626         prepare_packed_git_run_once = 1;
627 }
628
629 static void reprepare_packed_git(void)
630 {
631         prepare_packed_git_run_once = 0;
632         prepare_packed_git();
633 }
634
635 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
636 {
637         char header[100];
638         unsigned char real_sha1[20];
639         SHA_CTX c;
640
641         SHA1_Init(&c);
642         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
643         SHA1_Update(&c, map, size);
644         SHA1_Final(real_sha1, &c);
645         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
646 }
647
648 static void *map_sha1_file_internal(const unsigned char *sha1,
649                                     unsigned long *size)
650 {
651         struct stat st;
652         void *map;
653         int fd;
654         char *filename = find_sha1_file(sha1, &st);
655
656         if (!filename) {
657                 return NULL;
658         }
659
660         fd = open(filename, O_RDONLY | sha1_file_open_flag);
661         if (fd < 0) {
662                 /* See if it works without O_NOATIME */
663                 switch (sha1_file_open_flag) {
664                 default:
665                         fd = open(filename, O_RDONLY);
666                         if (fd >= 0)
667                                 break;
668                 /* Fallthrough */
669                 case 0:
670                         return NULL;
671                 }
672
673                 /* If it failed once, it will probably fail again.
674                  * Stop using O_NOATIME
675                  */
676                 sha1_file_open_flag = 0;
677         }
678         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
679         close(fd);
680         if (map == MAP_FAILED)
681                 return NULL;
682         *size = st.st_size;
683         return map;
684 }
685
686 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
687 {
688         /* Get the data stream */
689         memset(stream, 0, sizeof(*stream));
690         stream->next_in = map;
691         stream->avail_in = mapsize;
692         stream->next_out = buffer;
693         stream->avail_out = size;
694
695         inflateInit(stream);
696         return inflate(stream, 0);
697 }
698
699 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
700 {
701         int bytes = strlen(buffer) + 1;
702         unsigned char *buf = xmalloc(1+size);
703
704         memcpy(buf, buffer + bytes, stream->total_out - bytes);
705         bytes = stream->total_out - bytes;
706         if (bytes < size) {
707                 stream->next_out = buf + bytes;
708                 stream->avail_out = size - bytes;
709                 while (inflate(stream, Z_FINISH) == Z_OK)
710                         /* nothing */;
711         }
712         buf[size] = 0;
713         inflateEnd(stream);
714         return buf;
715 }
716
717 /*
718  * We used to just use "sscanf()", but that's actually way
719  * too permissive for what we want to check. So do an anal
720  * object header parse by hand.
721  */
722 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
723 {
724         int i;
725         unsigned long size;
726
727         /*
728          * The type can be at most ten bytes (including the 
729          * terminating '\0' that we add), and is followed by
730          * a space. 
731          */
732         i = 10;
733         for (;;) {
734                 char c = *hdr++;
735                 if (c == ' ')
736                         break;
737                 if (!--i)
738                         return -1;
739                 *type++ = c;
740         }
741         *type = 0;
742
743         /*
744          * The length must follow immediately, and be in canonical
745          * decimal format (ie "010" is not valid).
746          */
747         size = *hdr++ - '0';
748         if (size > 9)
749                 return -1;
750         if (size) {
751                 for (;;) {
752                         unsigned long c = *hdr - '0';
753                         if (c > 9)
754                                 break;
755                         hdr++;
756                         size = size * 10 + c;
757                 }
758         }
759         *sizep = size;
760
761         /*
762          * The length must be followed by a zero byte
763          */
764         return *hdr ? -1 : 0;
765 }
766
767 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
768 {
769         int ret;
770         z_stream stream;
771         char hdr[8192];
772
773         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
774         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
775                 return NULL;
776
777         return unpack_sha1_rest(&stream, hdr, *size);
778 }
779
780 /* forward declaration for a mutually recursive function */
781 static int packed_object_info(struct pack_entry *entry,
782                               char *type, unsigned long *sizep);
783
784 static int packed_delta_info(unsigned char *base_sha1,
785                              unsigned long delta_size,
786                              unsigned long left,
787                              char *type,
788                              unsigned long *sizep,
789                              struct packed_git *p)
790 {
791         struct pack_entry base_ent;
792
793         if (left < 20)
794                 die("truncated pack file");
795
796         /* The base entry _must_ be in the same pack */
797         if (!find_pack_entry_one(base_sha1, &base_ent, p))
798                 die("failed to find delta-pack base object %s",
799                     sha1_to_hex(base_sha1));
800
801         /* We choose to only get the type of the base object and
802          * ignore potentially corrupt pack file that expects the delta
803          * based on a base with a wrong size.  This saves tons of
804          * inflate() calls.
805          */
806
807         if (packed_object_info(&base_ent, type, NULL))
808                 die("cannot get info for delta-pack base");
809
810         if (sizep) {
811                 const unsigned char *data;
812                 unsigned char delta_head[64];
813                 unsigned long result_size;
814                 z_stream stream;
815                 int st;
816
817                 memset(&stream, 0, sizeof(stream));
818
819                 data = stream.next_in = base_sha1 + 20;
820                 stream.avail_in = left - 20;
821                 stream.next_out = delta_head;
822                 stream.avail_out = sizeof(delta_head);
823
824                 inflateInit(&stream);
825                 st = inflate(&stream, Z_FINISH);
826                 inflateEnd(&stream);
827                 if ((st != Z_STREAM_END) &&
828                     stream.total_out != sizeof(delta_head))
829                         die("delta data unpack-initial failed");
830
831                 /* Examine the initial part of the delta to figure out
832                  * the result size.
833                  */
834                 data = delta_head;
835
836                 /* ignore base size */
837                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
838
839                 /* Read the result size */
840                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
841                 *sizep = result_size;
842         }
843         return 0;
844 }
845
846 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
847         enum object_type *type, unsigned long *sizep)
848 {
849         unsigned shift;
850         unsigned char *pack, c;
851         unsigned long size;
852
853         if (offset >= p->pack_size)
854                 die("object offset outside of pack file");
855
856         pack =  p->pack_base + offset;
857         c = *pack++;
858         offset++;
859         *type = (c >> 4) & 7;
860         size = c & 15;
861         shift = 4;
862         while (c & 0x80) {
863                 if (offset >= p->pack_size)
864                         die("object offset outside of pack file");
865                 c = *pack++;
866                 offset++;
867                 size += (c & 0x7f) << shift;
868                 shift += 7;
869         }
870         *sizep = size;
871         return offset;
872 }
873
874 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
875                            unsigned char *base, unsigned long *sizep,
876                            enum object_type *kindp)
877 {
878         unsigned long ptr;
879         int status = -1;
880
881         use_packed_git(p);
882         ptr = offset;
883         ptr = unpack_object_header(p, ptr, kindp, sizep);
884         if (*kindp != OBJ_DELTA)
885                 goto done;
886         memcpy(base, p->pack_base + ptr, 20);
887         status = 0;
888  done:
889         unuse_packed_git(p);
890         return status;
891 }
892
893 void packed_object_info_detail(struct pack_entry *e,
894                                char *type,
895                                unsigned long *size,
896                                unsigned long *store_size,
897                                unsigned int *delta_chain_length,
898                                unsigned char *base_sha1)
899 {
900         struct packed_git *p = e->p;
901         unsigned long offset;
902         unsigned char *pack;
903         enum object_type kind;
904
905         offset = unpack_object_header(p, e->offset, &kind, size);
906         pack = p->pack_base + offset;
907         if (kind != OBJ_DELTA)
908                 *delta_chain_length = 0;
909         else {
910                 unsigned int chain_length = 0;
911                 if (p->pack_size <= offset + 20)
912                         die("pack file %s records an incomplete delta base",
913                             p->pack_name);
914                 memcpy(base_sha1, pack, 20);
915                 do {
916                         struct pack_entry base_ent;
917                         unsigned long junk;
918
919                         find_pack_entry_one(pack, &base_ent, p);
920                         offset = unpack_object_header(p, base_ent.offset,
921                                                       &kind, &junk);
922                         pack = p->pack_base + offset;
923                         chain_length++;
924                 } while (kind == OBJ_DELTA);
925                 *delta_chain_length = chain_length;
926         }
927         switch (kind) {
928         case OBJ_COMMIT:
929                 strcpy(type, commit_type);
930                 break;
931         case OBJ_TREE:
932                 strcpy(type, tree_type);
933                 break;
934         case OBJ_BLOB:
935                 strcpy(type, blob_type);
936                 break;
937         case OBJ_TAG:
938                 strcpy(type, tag_type);
939                 break;
940         default:
941                 die("corrupted pack file %s containing object of kind %d",
942                     p->pack_name, kind);
943         }
944         *store_size = 0; /* notyet */
945 }
946
947 static int packed_object_info(struct pack_entry *entry,
948                               char *type, unsigned long *sizep)
949 {
950         struct packed_git *p = entry->p;
951         unsigned long offset, size, left;
952         unsigned char *pack;
953         enum object_type kind;
954         int retval;
955
956         if (use_packed_git(p))
957                 die("cannot map packed file");
958
959         offset = unpack_object_header(p, entry->offset, &kind, &size);
960         pack = p->pack_base + offset;
961         left = p->pack_size - offset;
962
963         switch (kind) {
964         case OBJ_DELTA:
965                 retval = packed_delta_info(pack, size, left, type, sizep, p);
966                 unuse_packed_git(p);
967                 return retval;
968         case OBJ_COMMIT:
969                 strcpy(type, commit_type);
970                 break;
971         case OBJ_TREE:
972                 strcpy(type, tree_type);
973                 break;
974         case OBJ_BLOB:
975                 strcpy(type, blob_type);
976                 break;
977         case OBJ_TAG:
978                 strcpy(type, tag_type);
979                 break;
980         default:
981                 die("corrupted pack file %s containing object of kind %d",
982                     p->pack_name, kind);
983         }
984         if (sizep)
985                 *sizep = size;
986         unuse_packed_git(p);
987         return 0;
988 }
989
990 /* forward declaration for a mutually recursive function */
991 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
992
993 static void *unpack_delta_entry(unsigned char *base_sha1,
994                                 unsigned long delta_size,
995                                 unsigned long left,
996                                 char *type,
997                                 unsigned long *sizep,
998                                 struct packed_git *p)
999 {
1000         struct pack_entry base_ent;
1001         void *data, *delta_data, *result, *base;
1002         unsigned long data_size, result_size, base_size;
1003         z_stream stream;
1004         int st;
1005
1006         if (left < 20)
1007                 die("truncated pack file");
1008
1009         /* The base entry _must_ be in the same pack */
1010         if (!find_pack_entry_one(base_sha1, &base_ent, p))
1011                 die("failed to find delta-pack base object %s",
1012                     sha1_to_hex(base_sha1));
1013         base = unpack_entry_gently(&base_ent, type, &base_size);
1014         if (!base)
1015                 die("failed to read delta-pack base object %s",
1016                     sha1_to_hex(base_sha1));
1017
1018         data = base_sha1 + 20;
1019         data_size = left - 20;
1020         delta_data = xmalloc(delta_size);
1021
1022         memset(&stream, 0, sizeof(stream));
1023
1024         stream.next_in = data;
1025         stream.avail_in = data_size;
1026         stream.next_out = delta_data;
1027         stream.avail_out = delta_size;
1028
1029         inflateInit(&stream);
1030         st = inflate(&stream, Z_FINISH);
1031         inflateEnd(&stream);
1032         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
1033                 die("delta data unpack failed");
1034
1035         result = patch_delta(base, base_size,
1036                              delta_data, delta_size,
1037                              &result_size);
1038         if (!result)
1039                 die("failed to apply delta");
1040         free(delta_data);
1041         free(base);
1042         *sizep = result_size;
1043         return result;
1044 }
1045
1046 static void *unpack_non_delta_entry(unsigned char *data,
1047                                     unsigned long size,
1048                                     unsigned long left)
1049 {
1050         int st;
1051         z_stream stream;
1052         unsigned char *buffer;
1053
1054         buffer = xmalloc(size + 1);
1055         buffer[size] = 0;
1056         memset(&stream, 0, sizeof(stream));
1057         stream.next_in = data;
1058         stream.avail_in = left;
1059         stream.next_out = buffer;
1060         stream.avail_out = size;
1061
1062         inflateInit(&stream);
1063         st = inflate(&stream, Z_FINISH);
1064         inflateEnd(&stream);
1065         if ((st != Z_STREAM_END) || stream.total_out != size) {
1066                 free(buffer);
1067                 return NULL;
1068         }
1069
1070         return buffer;
1071 }
1072
1073 static void *unpack_entry(struct pack_entry *entry,
1074                           char *type, unsigned long *sizep)
1075 {
1076         struct packed_git *p = entry->p;
1077         void *retval;
1078
1079         if (use_packed_git(p))
1080                 die("cannot map packed file");
1081         retval = unpack_entry_gently(entry, type, sizep);
1082         unuse_packed_git(p);
1083         if (!retval)
1084                 die("corrupted pack file %s", p->pack_name);
1085         return retval;
1086 }
1087
1088 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1089 void *unpack_entry_gently(struct pack_entry *entry,
1090                           char *type, unsigned long *sizep)
1091 {
1092         struct packed_git *p = entry->p;
1093         unsigned long offset, size, left;
1094         unsigned char *pack;
1095         enum object_type kind;
1096         void *retval;
1097
1098         offset = unpack_object_header(p, entry->offset, &kind, &size);
1099         pack = p->pack_base + offset;
1100         left = p->pack_size - offset;
1101         switch (kind) {
1102         case OBJ_DELTA:
1103                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1104                 return retval;
1105         case OBJ_COMMIT:
1106                 strcpy(type, commit_type);
1107                 break;
1108         case OBJ_TREE:
1109                 strcpy(type, tree_type);
1110                 break;
1111         case OBJ_BLOB:
1112                 strcpy(type, blob_type);
1113                 break;
1114         case OBJ_TAG:
1115                 strcpy(type, tag_type);
1116                 break;
1117         default:
1118                 return NULL;
1119         }
1120         *sizep = size;
1121         retval = unpack_non_delta_entry(pack, size, left);
1122         return retval;
1123 }
1124
1125 int num_packed_objects(const struct packed_git *p)
1126 {
1127         /* See check_packed_git_idx() */
1128         return (p->index_size - 20 - 20 - 4*256) / 24;
1129 }
1130
1131 int nth_packed_object_sha1(const struct packed_git *p, int n,
1132                            unsigned char* sha1)
1133 {
1134         void *index = p->index_base + 256;
1135         if (n < 0 || num_packed_objects(p) <= n)
1136                 return -1;
1137         memcpy(sha1, (index + 24 * n + 4), 20);
1138         return 0;
1139 }
1140
1141 int find_pack_entry_one(const unsigned char *sha1,
1142                         struct pack_entry *e, struct packed_git *p)
1143 {
1144         unsigned int *level1_ofs = p->index_base;
1145         int hi = ntohl(level1_ofs[*sha1]);
1146         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1147         void *index = p->index_base + 256;
1148
1149         do {
1150                 int mi = (lo + hi) / 2;
1151                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1152                 if (!cmp) {
1153                         e->offset = ntohl(*((unsigned int *)(index + 24 * mi)));
1154                         memcpy(e->sha1, sha1, 20);
1155                         e->p = p;
1156                         return 1;
1157                 }
1158                 if (cmp > 0)
1159                         hi = mi;
1160                 else
1161                         lo = mi+1;
1162         } while (lo < hi);
1163         return 0;
1164 }
1165
1166 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1167 {
1168         struct packed_git *p;
1169         prepare_packed_git();
1170
1171         for (p = packed_git; p; p = p->next) {
1172                 if (find_pack_entry_one(sha1, e, p))
1173                         return 1;
1174         }
1175         return 0;
1176 }
1177
1178 struct packed_git *find_sha1_pack(const unsigned char *sha1, 
1179                                   struct packed_git *packs)
1180 {
1181         struct packed_git *p;
1182         struct pack_entry e;
1183
1184         for (p = packs; p; p = p->next) {
1185                 if (find_pack_entry_one(sha1, &e, p))
1186                         return p;
1187         }
1188         return NULL;
1189         
1190 }
1191
1192 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1193 {
1194         int status;
1195         unsigned long mapsize, size;
1196         void *map;
1197         z_stream stream;
1198         char hdr[128];
1199
1200         map = map_sha1_file_internal(sha1, &mapsize);
1201         if (!map) {
1202                 struct pack_entry e;
1203
1204                 if (find_pack_entry(sha1, &e))
1205                         return packed_object_info(&e, type, sizep);
1206                 reprepare_packed_git();
1207                 if (find_pack_entry(sha1, &e))
1208                         return packed_object_info(&e, type, sizep);
1209                 return error("unable to find %s", sha1_to_hex(sha1));
1210         }
1211         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1212                 status = error("unable to unpack %s header",
1213                                sha1_to_hex(sha1));
1214         if (parse_sha1_header(hdr, type, &size) < 0)
1215                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1216         else {
1217                 status = 0;
1218                 if (sizep)
1219                         *sizep = size;
1220         }
1221         inflateEnd(&stream);
1222         munmap(map, mapsize);
1223         return status;
1224 }
1225
1226 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1227 {
1228         struct pack_entry e;
1229
1230         if (!find_pack_entry(sha1, &e)) {
1231                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1232                 return NULL;
1233         }
1234         return unpack_entry(&e, type, size);
1235 }
1236
1237 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1238 {
1239         unsigned long mapsize;
1240         void *map, *buf;
1241         struct pack_entry e;
1242
1243         if (find_pack_entry(sha1, &e))
1244                 return read_packed_sha1(sha1, type, size);
1245         map = map_sha1_file_internal(sha1, &mapsize);
1246         if (map) {
1247                 buf = unpack_sha1_file(map, mapsize, type, size);
1248                 munmap(map, mapsize);
1249                 return buf;
1250         }
1251         reprepare_packed_git();
1252         if (find_pack_entry(sha1, &e))
1253                 return read_packed_sha1(sha1, type, size);
1254         return NULL;
1255 }
1256
1257 void *read_object_with_reference(const unsigned char *sha1,
1258                                  const char *required_type,
1259                                  unsigned long *size,
1260                                  unsigned char *actual_sha1_return)
1261 {
1262         char type[20];
1263         void *buffer;
1264         unsigned long isize;
1265         unsigned char actual_sha1[20];
1266
1267         memcpy(actual_sha1, sha1, 20);
1268         while (1) {
1269                 int ref_length = -1;
1270                 const char *ref_type = NULL;
1271
1272                 buffer = read_sha1_file(actual_sha1, type, &isize);
1273                 if (!buffer)
1274                         return NULL;
1275                 if (!strcmp(type, required_type)) {
1276                         *size = isize;
1277                         if (actual_sha1_return)
1278                                 memcpy(actual_sha1_return, actual_sha1, 20);
1279                         return buffer;
1280                 }
1281                 /* Handle references */
1282                 else if (!strcmp(type, commit_type))
1283                         ref_type = "tree ";
1284                 else if (!strcmp(type, tag_type))
1285                         ref_type = "object ";
1286                 else {
1287                         free(buffer);
1288                         return NULL;
1289                 }
1290                 ref_length = strlen(ref_type);
1291
1292                 if (memcmp(buffer, ref_type, ref_length) ||
1293                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1294                         free(buffer);
1295                         return NULL;
1296                 }
1297                 free(buffer);
1298                 /* Now we have the ID of the referred-to object in
1299                  * actual_sha1.  Check again. */
1300         }
1301 }
1302
1303 char *write_sha1_file_prepare(void *buf,
1304                               unsigned long len,
1305                               const char *type,
1306                               unsigned char *sha1,
1307                               unsigned char *hdr,
1308                               int *hdrlen)
1309 {
1310         SHA_CTX c;
1311
1312         /* Generate the header */
1313         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1314
1315         /* Sha1.. */
1316         SHA1_Init(&c);
1317         SHA1_Update(&c, hdr, *hdrlen);
1318         SHA1_Update(&c, buf, len);
1319         SHA1_Final(sha1, &c);
1320
1321         return sha1_file_name(sha1);
1322 }
1323
1324 /*
1325  * Link the tempfile to the final place, possibly creating the
1326  * last directory level as you do so.
1327  *
1328  * Returns the errno on failure, 0 on success.
1329  */
1330 static int link_temp_to_file(const char *tmpfile, char *filename)
1331 {
1332         int ret;
1333
1334         if (!link(tmpfile, filename))
1335                 return 0;
1336
1337         /*
1338          * Try to mkdir the last path component if that failed
1339          * with an ENOENT.
1340          *
1341          * Re-try the "link()" regardless of whether the mkdir
1342          * succeeds, since a race might mean that somebody
1343          * else succeeded.
1344          */
1345         ret = errno;
1346         if (ret == ENOENT) {
1347                 char *dir = strrchr(filename, '/');
1348                 if (dir) {
1349                         *dir = 0;
1350                         mkdir(filename, 0777);
1351                         if (adjust_shared_perm(filename))
1352                                 return -2;
1353                         *dir = '/';
1354                         if (!link(tmpfile, filename))
1355                                 return 0;
1356                         ret = errno;
1357                 }
1358         }
1359         return ret;
1360 }
1361
1362 /*
1363  * Move the just written object into its final resting place
1364  */
1365 int move_temp_to_file(const char *tmpfile, char *filename)
1366 {
1367         int ret = link_temp_to_file(tmpfile, filename);
1368
1369         /*
1370          * Coda hack - coda doesn't like cross-directory links,
1371          * so we fall back to a rename, which will mean that it
1372          * won't be able to check collisions, but that's not a
1373          * big deal.
1374          *
1375          * The same holds for FAT formatted media.
1376          *
1377          * When this succeeds, we just return 0. We have nothing
1378          * left to unlink.
1379          */
1380         if (ret && ret != EEXIST) {
1381                 if (!rename(tmpfile, filename))
1382                         return 0;
1383                 ret = errno;
1384         }
1385         unlink(tmpfile);
1386         if (ret) {
1387                 if (ret != EEXIST) {
1388                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1389                         return -1;
1390                 }
1391                 /* FIXME!!! Collision check here ? */
1392         }
1393
1394         return 0;
1395 }
1396
1397 static int write_buffer(int fd, const void *buf, size_t len)
1398 {
1399         while (len) {
1400                 ssize_t size;
1401
1402                 size = write(fd, buf, len);
1403                 if (!size)
1404                         return error("file write: disk full");
1405                 if (size < 0) {
1406                         if (errno == EINTR || errno == EAGAIN)
1407                                 continue;
1408                         return error("file write error (%s)", strerror(errno));
1409                 }
1410                 len -= size;
1411                 buf += size;
1412         }
1413         return 0;
1414 }
1415
1416 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1417 {
1418         int size;
1419         unsigned char *compressed;
1420         z_stream stream;
1421         unsigned char sha1[20];
1422         char *filename;
1423         static char tmpfile[PATH_MAX];
1424         unsigned char hdr[50];
1425         int fd, hdrlen;
1426
1427         /* Normally if we have it in the pack then we do not bother writing
1428          * it out into .git/objects/??/?{38} file.
1429          */
1430         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1431         if (returnsha1)
1432                 memcpy(returnsha1, sha1, 20);
1433         if (has_sha1_file(sha1))
1434                 return 0;
1435         fd = open(filename, O_RDONLY);
1436         if (fd >= 0) {
1437                 /*
1438                  * FIXME!!! We might do collision checking here, but we'd
1439                  * need to uncompress the old file and check it. Later.
1440                  */
1441                 close(fd);
1442                 return 0;
1443         }
1444
1445         if (errno != ENOENT) {
1446                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1447                 return -1;
1448         }
1449
1450         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1451
1452         fd = mkstemp(tmpfile);
1453         if (fd < 0) {
1454                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1455                 return -1;
1456         }
1457
1458         /* Set it up */
1459         memset(&stream, 0, sizeof(stream));
1460         deflateInit(&stream, Z_BEST_COMPRESSION);
1461         size = deflateBound(&stream, len+hdrlen);
1462         compressed = xmalloc(size);
1463
1464         /* Compress it */
1465         stream.next_out = compressed;
1466         stream.avail_out = size;
1467
1468         /* First header.. */
1469         stream.next_in = hdr;
1470         stream.avail_in = hdrlen;
1471         while (deflate(&stream, 0) == Z_OK)
1472                 /* nothing */;
1473
1474         /* Then the data itself.. */
1475         stream.next_in = buf;
1476         stream.avail_in = len;
1477         while (deflate(&stream, Z_FINISH) == Z_OK)
1478                 /* nothing */;
1479         deflateEnd(&stream);
1480         size = stream.total_out;
1481
1482         if (write_buffer(fd, compressed, size) < 0)
1483                 die("unable to write sha1 file");
1484         fchmod(fd, 0444);
1485         close(fd);
1486         free(compressed);
1487
1488         return move_temp_to_file(tmpfile, filename);
1489 }
1490
1491 /*
1492  * We need to unpack and recompress the object for writing
1493  * it out to a different file.
1494  */
1495 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1496 {
1497         size_t size;
1498         z_stream stream;
1499         unsigned char *unpacked;
1500         unsigned long len;
1501         char type[20];
1502         char hdr[50];
1503         int hdrlen;
1504         void *buf;
1505
1506         // need to unpack and recompress it by itself
1507         unpacked = read_packed_sha1(sha1, type, &len);
1508
1509         hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1510
1511         /* Set it up */
1512         memset(&stream, 0, sizeof(stream));
1513         deflateInit(&stream, Z_BEST_COMPRESSION);
1514         size = deflateBound(&stream, len + hdrlen);
1515         buf = xmalloc(size);
1516
1517         /* Compress it */
1518         stream.next_out = buf;
1519         stream.avail_out = size;
1520
1521         /* First header.. */
1522         stream.next_in = (void *)hdr;
1523         stream.avail_in = hdrlen;
1524         while (deflate(&stream, 0) == Z_OK)
1525                 /* nothing */;
1526
1527         /* Then the data itself.. */
1528         stream.next_in = unpacked;
1529         stream.avail_in = len;
1530         while (deflate(&stream, Z_FINISH) == Z_OK)
1531                 /* nothing */;
1532         deflateEnd(&stream);
1533         free(unpacked);
1534
1535         *objsize = stream.total_out;
1536         return buf;
1537 }
1538
1539 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1540 {
1541         int retval;
1542         unsigned long objsize;
1543         void *buf = map_sha1_file_internal(sha1, &objsize);
1544
1545         if (buf) {
1546                 retval = write_buffer(fd, buf, objsize);
1547                 munmap(buf, objsize);
1548                 return retval;
1549         }
1550
1551         buf = repack_object(sha1, &objsize);
1552         retval = write_buffer(fd, buf, objsize);
1553         free(buf);
1554         return retval;
1555 }
1556
1557 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1558                        size_t bufsize, size_t *bufposn)
1559 {
1560         char tmpfile[PATH_MAX];
1561         int local;
1562         z_stream stream;
1563         unsigned char real_sha1[20];
1564         unsigned char discard[4096];
1565         int ret;
1566         SHA_CTX c;
1567
1568         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1569
1570         local = mkstemp(tmpfile);
1571         if (local < 0)
1572                 return error("Couldn't open %s for %s",
1573                              tmpfile, sha1_to_hex(sha1));
1574
1575         memset(&stream, 0, sizeof(stream));
1576
1577         inflateInit(&stream);
1578
1579         SHA1_Init(&c);
1580
1581         do {
1582                 ssize_t size;
1583                 if (*bufposn) {
1584                         stream.avail_in = *bufposn;
1585                         stream.next_in = (unsigned char *) buffer;
1586                         do {
1587                                 stream.next_out = discard;
1588                                 stream.avail_out = sizeof(discard);
1589                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1590                                 SHA1_Update(&c, discard, sizeof(discard) -
1591                                             stream.avail_out);
1592                         } while (stream.avail_in && ret == Z_OK);
1593                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1594                                 die("unable to write sha1 file");
1595                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1596                                 stream.avail_in);
1597                         *bufposn = stream.avail_in;
1598                         if (ret != Z_OK)
1599                                 break;
1600                 }
1601                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1602                 if (size <= 0) {
1603                         close(local);
1604                         unlink(tmpfile);
1605                         if (!size)
1606                                 return error("Connection closed?");
1607                         perror("Reading from connection");
1608                         return -1;
1609                 }
1610                 *bufposn += size;
1611         } while (1);
1612         inflateEnd(&stream);
1613
1614         close(local);
1615         SHA1_Final(real_sha1, &c);
1616         if (ret != Z_STREAM_END) {
1617                 unlink(tmpfile);
1618                 return error("File %s corrupted", sha1_to_hex(sha1));
1619         }
1620         if (memcmp(sha1, real_sha1, 20)) {
1621                 unlink(tmpfile);
1622                 return error("File %s has bad hash", sha1_to_hex(sha1));
1623         }
1624
1625         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1626 }
1627
1628 int has_pack_index(const unsigned char *sha1)
1629 {
1630         struct stat st;
1631         if (stat(sha1_pack_index_name(sha1), &st))
1632                 return 0;
1633         return 1;
1634 }
1635
1636 int has_pack_file(const unsigned char *sha1)
1637 {
1638         struct stat st;
1639         if (stat(sha1_pack_name(sha1), &st))
1640                 return 0;
1641         return 1;
1642 }
1643
1644 int has_sha1_pack(const unsigned char *sha1)
1645 {
1646         struct pack_entry e;
1647         return find_pack_entry(sha1, &e);
1648 }
1649
1650 int has_sha1_file(const unsigned char *sha1)
1651 {
1652         struct stat st;
1653         struct pack_entry e;
1654
1655         if (find_pack_entry(sha1, &e))
1656                 return 1;
1657         return find_sha1_file(sha1, &st) ? 1 : 0;
1658 }
1659
1660 /*
1661  * reads from fd as long as possible into a supplied buffer of size bytes.
1662  * If neccessary the buffer's size is increased using realloc()
1663  *
1664  * returns 0 if anything went fine and -1 otherwise
1665  *
1666  * NOTE: both buf and size may change, but even when -1 is returned
1667  * you still have to free() it yourself.
1668  */
1669 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1670 {
1671         char* buf = *return_buf;
1672         unsigned long size = *return_size;
1673         int iret;
1674         unsigned long off = 0;
1675
1676         do {
1677                 iret = xread(fd, buf + off, size - off);
1678                 if (iret > 0) {
1679                         off += iret;
1680                         if (off == size) {
1681                                 size *= 2;
1682                                 buf = realloc(buf, size);
1683                         }
1684                 }
1685         } while (iret > 0);
1686
1687         *return_buf = buf;
1688         *return_size = off;
1689
1690         if (iret < 0)
1691                 return -1;
1692         return 0;
1693 }
1694
1695 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1696 {
1697         unsigned long size = 4096;
1698         char *buf = malloc(size);
1699         int ret;
1700         unsigned char hdr[50];
1701         int hdrlen;
1702
1703         if (read_pipe(fd, &buf, &size)) {
1704                 free(buf);
1705                 return -1;
1706         }
1707
1708         if (!type)
1709                 type = blob_type;
1710         if (write_object)
1711                 ret = write_sha1_file(buf, size, type, sha1);
1712         else {
1713                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1714                 ret = 0;
1715         }
1716         free(buf);
1717         return ret;
1718 }
1719
1720 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1721 {
1722         unsigned long size = st->st_size;
1723         void *buf;
1724         int ret;
1725         unsigned char hdr[50];
1726         int hdrlen;
1727
1728         buf = "";
1729         if (size)
1730                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1731         close(fd);
1732         if (buf == MAP_FAILED)
1733                 return -1;
1734
1735         if (!type)
1736                 type = blob_type;
1737         if (write_object)
1738                 ret = write_sha1_file(buf, size, type, sha1);
1739         else {
1740                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1741                 ret = 0;
1742         }
1743         if (size)
1744                 munmap(buf, size);
1745         return ret;
1746 }
1747
1748 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1749 {
1750         int fd;
1751         char *target;
1752
1753         switch (st->st_mode & S_IFMT) {
1754         case S_IFREG:
1755                 fd = open(path, O_RDONLY);
1756                 if (fd < 0)
1757                         return error("open(\"%s\"): %s", path,
1758                                      strerror(errno));
1759                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1760                         return error("%s: failed to insert into database",
1761                                      path);
1762                 break;
1763         case S_IFLNK:
1764                 target = xmalloc(st->st_size+1);
1765                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1766                         char *errstr = strerror(errno);
1767                         free(target);
1768                         return error("readlink(\"%s\"): %s", path,
1769                                      errstr);
1770                 }
1771                 if (!write_object) {
1772                         unsigned char hdr[50];
1773                         int hdrlen;
1774                         write_sha1_file_prepare(target, st->st_size, blob_type,
1775                                                 sha1, hdr, &hdrlen);
1776                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1777                         return error("%s: failed to insert into database",
1778                                      path);
1779                 free(target);
1780                 break;
1781         default:
1782                 return error("%s: unsupported file type", path);
1783         }
1784         return 0;
1785 }