make overflow test on delta base offset work regardless of variable size
[git] / index-pack.c
1 #include "cache.h"
2 #include "delta.h"
3 #include "pack.h"
4 #include "csum-file.h"
5 #include "blob.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "tree.h"
9
10 static const char index_pack_usage[] =
11 "git-index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
12
13 struct object_entry
14 {
15         unsigned long offset;
16         unsigned long size;
17         unsigned int hdr_size;
18         enum object_type type;
19         enum object_type real_type;
20         unsigned char sha1[20];
21 };
22
23 union delta_base {
24         unsigned char sha1[20];
25         unsigned long offset;
26 };
27
28 /*
29  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
30  * to memcmp() only the first 20 bytes.
31  */
32 #define UNION_BASE_SZ   20
33
34 struct delta_entry
35 {
36         union delta_base base;
37         int obj_no;
38 };
39
40 static struct object_entry *objects;
41 static struct delta_entry *deltas;
42 static int nr_objects;
43 static int nr_deltas;
44 static int nr_resolved_deltas;
45
46 static int from_stdin;
47 static int verbose;
48
49 static volatile sig_atomic_t progress_update;
50
51 static void progress_interval(int signum)
52 {
53         progress_update = 1;
54 }
55
56 static void setup_progress_signal(void)
57 {
58         struct sigaction sa;
59         struct itimerval v;
60
61         memset(&sa, 0, sizeof(sa));
62         sa.sa_handler = progress_interval;
63         sigemptyset(&sa.sa_mask);
64         sa.sa_flags = SA_RESTART;
65         sigaction(SIGALRM, &sa, NULL);
66
67         v.it_interval.tv_sec = 1;
68         v.it_interval.tv_usec = 0;
69         v.it_value = v.it_interval;
70         setitimer(ITIMER_REAL, &v, NULL);
71
72 }
73
74 static unsigned display_progress(unsigned n, unsigned total, unsigned last_pc)
75 {
76         unsigned percent = n * 100 / total;
77         if (percent != last_pc || progress_update) {
78                 fprintf(stderr, "%4u%% (%u/%u) done\r", percent, n, total);
79                 progress_update = 0;
80         }
81         return percent;
82 }
83
84 /* We always read in 4kB chunks. */
85 static unsigned char input_buffer[4096];
86 static unsigned long input_offset, input_len, consumed_bytes;
87 static SHA_CTX input_ctx;
88 static int input_fd, output_fd, pack_fd;
89
90 /* Discard current buffer used content. */
91 static void flush(void)
92 {
93         if (input_offset) {
94                 if (output_fd >= 0)
95                         write_or_die(output_fd, input_buffer, input_offset);
96                 SHA1_Update(&input_ctx, input_buffer, input_offset);
97                 memmove(input_buffer, input_buffer + input_offset, input_len);
98                 input_offset = 0;
99         }
100 }
101
102 /*
103  * Make sure at least "min" bytes are available in the buffer, and
104  * return the pointer to the buffer.
105  */
106 static void *fill(int min)
107 {
108         if (min <= input_len)
109                 return input_buffer + input_offset;
110         if (min > sizeof(input_buffer))
111                 die("cannot fill %d bytes", min);
112         flush();
113         do {
114                 int ret = xread(input_fd, input_buffer + input_len,
115                                 sizeof(input_buffer) - input_len);
116                 if (ret <= 0) {
117                         if (!ret)
118                                 die("early EOF");
119                         die("read error on input: %s", strerror(errno));
120                 }
121                 input_len += ret;
122         } while (input_len < min);
123         return input_buffer;
124 }
125
126 static void use(int bytes)
127 {
128         if (bytes > input_len)
129                 die("used more bytes than were available");
130         input_len -= bytes;
131         input_offset += bytes;
132         consumed_bytes += bytes;
133 }
134
135 static const char *open_pack_file(const char *pack_name)
136 {
137         if (from_stdin) {
138                 input_fd = 0;
139                 if (!pack_name) {
140                         static char tmpfile[PATH_MAX];
141                         snprintf(tmpfile, sizeof(tmpfile),
142                                  "%s/tmp_pack_XXXXXX", get_object_directory());
143                         output_fd = mkstemp(tmpfile);
144                         pack_name = xstrdup(tmpfile);
145                 } else
146                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
147                 if (output_fd < 0)
148                         die("unable to create %s: %s\n", pack_name, strerror(errno));
149                 pack_fd = output_fd;
150         } else {
151                 input_fd = open(pack_name, O_RDONLY);
152                 if (input_fd < 0)
153                         die("cannot open packfile '%s': %s",
154                             pack_name, strerror(errno));
155                 output_fd = -1;
156                 pack_fd = input_fd;
157         }
158         SHA1_Init(&input_ctx);
159         return pack_name;
160 }
161
162 static void parse_pack_header(void)
163 {
164         struct pack_header *hdr = fill(sizeof(struct pack_header));
165
166         /* Header consistency check */
167         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
168                 die("pack signature mismatch");
169         if (!pack_version_ok(hdr->hdr_version))
170                 die("pack version %d unsupported", ntohl(hdr->hdr_version));
171
172         nr_objects = ntohl(hdr->hdr_entries);
173         use(sizeof(struct pack_header));
174 }
175
176 static void bad_object(unsigned long offset, const char *format,
177                        ...) NORETURN __attribute__((format (printf, 2, 3)));
178
179 static void bad_object(unsigned long offset, const char *format, ...)
180 {
181         va_list params;
182         char buf[1024];
183
184         va_start(params, format);
185         vsnprintf(buf, sizeof(buf), format, params);
186         va_end(params);
187         die("pack has bad object at offset %lu: %s", offset, buf);
188 }
189
190 static void *unpack_entry_data(unsigned long offset, unsigned long size)
191 {
192         z_stream stream;
193         void *buf = xmalloc(size);
194
195         memset(&stream, 0, sizeof(stream));
196         stream.next_out = buf;
197         stream.avail_out = size;
198         stream.next_in = fill(1);
199         stream.avail_in = input_len;
200         inflateInit(&stream);
201
202         for (;;) {
203                 int ret = inflate(&stream, 0);
204                 use(input_len - stream.avail_in);
205                 if (stream.total_out == size && ret == Z_STREAM_END)
206                         break;
207                 if (ret != Z_OK)
208                         bad_object(offset, "inflate returned %d", ret);
209                 stream.next_in = fill(1);
210                 stream.avail_in = input_len;
211         }
212         inflateEnd(&stream);
213         return buf;
214 }
215
216 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
217 {
218         unsigned char *p, c;
219         unsigned long size, base_offset;
220         unsigned shift;
221
222         obj->offset = consumed_bytes;
223
224         p = fill(1);
225         c = *p;
226         use(1);
227         obj->type = (c >> 4) & 7;
228         size = (c & 15);
229         shift = 4;
230         while (c & 0x80) {
231                 p = fill(1);
232                 c = *p;
233                 use(1);
234                 size += (c & 0x7fUL) << shift;
235                 shift += 7;
236         }
237         obj->size = size;
238
239         switch (obj->type) {
240         case OBJ_REF_DELTA:
241                 hashcpy(delta_base->sha1, fill(20));
242                 use(20);
243                 break;
244         case OBJ_OFS_DELTA:
245                 memset(delta_base, 0, sizeof(*delta_base));
246                 p = fill(1);
247                 c = *p;
248                 use(1);
249                 base_offset = c & 127;
250                 while (c & 128) {
251                         base_offset += 1;
252                         if (!base_offset || MSB(base_offset, 7))
253                                 bad_object(obj->offset, "offset value overflow for delta base object");
254                         p = fill(1);
255                         c = *p;
256                         use(1);
257                         base_offset = (base_offset << 7) + (c & 127);
258                 }
259                 delta_base->offset = obj->offset - base_offset;
260                 if (delta_base->offset >= obj->offset)
261                         bad_object(obj->offset, "delta base offset is out of bound");
262                 break;
263         case OBJ_COMMIT:
264         case OBJ_TREE:
265         case OBJ_BLOB:
266         case OBJ_TAG:
267                 break;
268         default:
269                 bad_object(obj->offset, "unknown object type %d", obj->type);
270         }
271         obj->hdr_size = consumed_bytes - obj->offset;
272
273         return unpack_entry_data(obj->offset, obj->size);
274 }
275
276 static void *get_data_from_pack(struct object_entry *obj)
277 {
278         unsigned long from = obj[0].offset + obj[0].hdr_size;
279         unsigned long len = obj[1].offset - from;
280         unsigned long rdy = 0;
281         unsigned char *src, *data;
282         z_stream stream;
283         int st;
284
285         src = xmalloc(len);
286         data = src;
287         do {
288                 ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
289                 if (n <= 0)
290                         die("cannot pread pack file: %s", strerror(errno));
291                 rdy += n;
292         } while (rdy < len);
293         data = xmalloc(obj->size);
294         memset(&stream, 0, sizeof(stream));
295         stream.next_out = data;
296         stream.avail_out = obj->size;
297         stream.next_in = src;
298         stream.avail_in = len;
299         inflateInit(&stream);
300         while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
301         inflateEnd(&stream);
302         if (st != Z_STREAM_END || stream.total_out != obj->size)
303                 die("serious inflate inconsistency");
304         free(src);
305         return data;
306 }
307
308 static int find_delta(const union delta_base *base)
309 {
310         int first = 0, last = nr_deltas;
311
312         while (first < last) {
313                 int next = (first + last) / 2;
314                 struct delta_entry *delta = &deltas[next];
315                 int cmp;
316
317                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
318                 if (!cmp)
319                         return next;
320                 if (cmp < 0) {
321                         last = next;
322                         continue;
323                 }
324                 first = next+1;
325         }
326         return -first-1;
327 }
328
329 static int find_delta_children(const union delta_base *base,
330                                int *first_index, int *last_index)
331 {
332         int first = find_delta(base);
333         int last = first;
334         int end = nr_deltas - 1;
335
336         if (first < 0)
337                 return -1;
338         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
339                 --first;
340         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
341                 ++last;
342         *first_index = first;
343         *last_index = last;
344         return 0;
345 }
346
347 static void sha1_object(const void *data, unsigned long size,
348                         enum object_type type, unsigned char *sha1)
349 {
350         hash_sha1_file(data, size, typename(type), sha1);
351         if (has_sha1_file(sha1)) {
352                 void *has_data;
353                 enum object_type has_type;
354                 unsigned long has_size;
355                 has_data = read_sha1_file(sha1, &has_type, &has_size);
356                 if (!has_data)
357                         die("cannot read existing object %s", sha1_to_hex(sha1));
358                 if (size != has_size || type != has_type ||
359                     memcmp(data, has_data, size) != 0)
360                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
361                 free(has_data);
362         }
363 }
364
365 static void resolve_delta(struct object_entry *delta_obj, void *base_data,
366                           unsigned long base_size, enum object_type type)
367 {
368         void *delta_data;
369         unsigned long delta_size;
370         void *result;
371         unsigned long result_size;
372         union delta_base delta_base;
373         int j, first, last;
374
375         delta_obj->real_type = type;
376         delta_data = get_data_from_pack(delta_obj);
377         delta_size = delta_obj->size;
378         result = patch_delta(base_data, base_size, delta_data, delta_size,
379                              &result_size);
380         free(delta_data);
381         if (!result)
382                 bad_object(delta_obj->offset, "failed to apply delta");
383         sha1_object(result, result_size, type, delta_obj->sha1);
384         nr_resolved_deltas++;
385
386         hashcpy(delta_base.sha1, delta_obj->sha1);
387         if (!find_delta_children(&delta_base, &first, &last)) {
388                 for (j = first; j <= last; j++) {
389                         struct object_entry *child = objects + deltas[j].obj_no;
390                         if (child->real_type == OBJ_REF_DELTA)
391                                 resolve_delta(child, result, result_size, type);
392                 }
393         }
394
395         memset(&delta_base, 0, sizeof(delta_base));
396         delta_base.offset = delta_obj->offset;
397         if (!find_delta_children(&delta_base, &first, &last)) {
398                 for (j = first; j <= last; j++) {
399                         struct object_entry *child = objects + deltas[j].obj_no;
400                         if (child->real_type == OBJ_OFS_DELTA)
401                                 resolve_delta(child, result, result_size, type);
402                 }
403         }
404
405         free(result);
406 }
407
408 static int compare_delta_entry(const void *a, const void *b)
409 {
410         const struct delta_entry *delta_a = a;
411         const struct delta_entry *delta_b = b;
412         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
413 }
414
415 /* Parse all objects and return the pack content SHA1 hash */
416 static void parse_pack_objects(unsigned char *sha1)
417 {
418         int i, percent = -1;
419         struct delta_entry *delta = deltas;
420         void *data;
421         struct stat st;
422
423         /*
424          * First pass:
425          * - find locations of all objects;
426          * - calculate SHA1 of all non-delta objects;
427          * - remember base (SHA1 or offset) for all deltas.
428          */
429         if (verbose)
430                 fprintf(stderr, "Indexing %d objects.\n", nr_objects);
431         for (i = 0; i < nr_objects; i++) {
432                 struct object_entry *obj = &objects[i];
433                 data = unpack_raw_entry(obj, &delta->base);
434                 obj->real_type = obj->type;
435                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
436                         nr_deltas++;
437                         delta->obj_no = i;
438                         delta++;
439                 } else
440                         sha1_object(data, obj->size, obj->type, obj->sha1);
441                 free(data);
442                 if (verbose)
443                         percent = display_progress(i+1, nr_objects, percent);
444         }
445         objects[i].offset = consumed_bytes;
446         if (verbose)
447                 fputc('\n', stderr);
448
449         /* Check pack integrity */
450         flush();
451         SHA1_Final(sha1, &input_ctx);
452         if (hashcmp(fill(20), sha1))
453                 die("pack is corrupted (SHA1 mismatch)");
454         use(20);
455
456         /* If input_fd is a file, we should have reached its end now. */
457         if (fstat(input_fd, &st))
458                 die("cannot fstat packfile: %s", strerror(errno));
459         if (S_ISREG(st.st_mode) &&
460                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
461                 die("pack has junk at the end");
462
463         if (!nr_deltas)
464                 return;
465
466         /* Sort deltas by base SHA1/offset for fast searching */
467         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
468               compare_delta_entry);
469
470         /*
471          * Second pass:
472          * - for all non-delta objects, look if it is used as a base for
473          *   deltas;
474          * - if used as a base, uncompress the object and apply all deltas,
475          *   recursively checking if the resulting object is used as a base
476          *   for some more deltas.
477          */
478         if (verbose)
479                 fprintf(stderr, "Resolving %d deltas.\n", nr_deltas);
480         for (i = 0; i < nr_objects; i++) {
481                 struct object_entry *obj = &objects[i];
482                 union delta_base base;
483                 int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
484
485                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
486                         continue;
487                 hashcpy(base.sha1, obj->sha1);
488                 ref = !find_delta_children(&base, &ref_first, &ref_last);
489                 memset(&base, 0, sizeof(base));
490                 base.offset = obj->offset;
491                 ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
492                 if (!ref && !ofs)
493                         continue;
494                 data = get_data_from_pack(obj);
495                 if (ref)
496                         for (j = ref_first; j <= ref_last; j++) {
497                                 struct object_entry *child = objects + deltas[j].obj_no;
498                                 if (child->real_type == OBJ_REF_DELTA)
499                                         resolve_delta(child, data,
500                                                       obj->size, obj->type);
501                         }
502                 if (ofs)
503                         for (j = ofs_first; j <= ofs_last; j++) {
504                                 struct object_entry *child = objects + deltas[j].obj_no;
505                                 if (child->real_type == OBJ_OFS_DELTA)
506                                         resolve_delta(child, data,
507                                                       obj->size, obj->type);
508                         }
509                 free(data);
510                 if (verbose)
511                         percent = display_progress(nr_resolved_deltas,
512                                                    nr_deltas, percent);
513         }
514         if (verbose && nr_resolved_deltas == nr_deltas)
515                 fputc('\n', stderr);
516 }
517
518 static int write_compressed(int fd, void *in, unsigned int size)
519 {
520         z_stream stream;
521         unsigned long maxsize;
522         void *out;
523
524         memset(&stream, 0, sizeof(stream));
525         deflateInit(&stream, zlib_compression_level);
526         maxsize = deflateBound(&stream, size);
527         out = xmalloc(maxsize);
528
529         /* Compress it */
530         stream.next_in = in;
531         stream.avail_in = size;
532         stream.next_out = out;
533         stream.avail_out = maxsize;
534         while (deflate(&stream, Z_FINISH) == Z_OK);
535         deflateEnd(&stream);
536
537         size = stream.total_out;
538         write_or_die(fd, out, size);
539         free(out);
540         return size;
541 }
542
543 static void append_obj_to_pack(const unsigned char *sha1, void *buf,
544                                unsigned long size, enum object_type type)
545 {
546         struct object_entry *obj = &objects[nr_objects++];
547         unsigned char header[10];
548         unsigned long s = size;
549         int n = 0;
550         unsigned char c = (type << 4) | (s & 15);
551         s >>= 4;
552         while (s) {
553                 header[n++] = c | 0x80;
554                 c = s & 0x7f;
555                 s >>= 7;
556         }
557         header[n++] = c;
558         write_or_die(output_fd, header, n);
559         obj[1].offset = obj[0].offset + n;
560         obj[1].offset += write_compressed(output_fd, buf, size);
561         hashcpy(obj->sha1, sha1);
562 }
563
564 static int delta_pos_compare(const void *_a, const void *_b)
565 {
566         struct delta_entry *a = *(struct delta_entry **)_a;
567         struct delta_entry *b = *(struct delta_entry **)_b;
568         return a->obj_no - b->obj_no;
569 }
570
571 static void fix_unresolved_deltas(int nr_unresolved)
572 {
573         struct delta_entry **sorted_by_pos;
574         int i, n = 0, percent = -1;
575
576         /*
577          * Since many unresolved deltas may well be themselves base objects
578          * for more unresolved deltas, we really want to include the
579          * smallest number of base objects that would cover as much delta
580          * as possible by picking the
581          * trunc deltas first, allowing for other deltas to resolve without
582          * additional base objects.  Since most base objects are to be found
583          * before deltas depending on them, a good heuristic is to start
584          * resolving deltas in the same order as their position in the pack.
585          */
586         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
587         for (i = 0; i < nr_deltas; i++) {
588                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
589                         continue;
590                 sorted_by_pos[n++] = &deltas[i];
591         }
592         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
593
594         for (i = 0; i < n; i++) {
595                 struct delta_entry *d = sorted_by_pos[i];
596                 void *data;
597                 unsigned long size;
598                 enum object_type type;
599                 int j, first, last;
600
601                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
602                         continue;
603                 data = read_sha1_file(d->base.sha1, &type, &size);
604                 if (!data)
605                         continue;
606
607                 find_delta_children(&d->base, &first, &last);
608                 for (j = first; j <= last; j++) {
609                         struct object_entry *child = objects + deltas[j].obj_no;
610                         if (child->real_type == OBJ_REF_DELTA)
611                                 resolve_delta(child, data, size, type);
612                 }
613
614                 if (check_sha1_signature(d->base.sha1, data, size, typename(type)))
615                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
616                 append_obj_to_pack(d->base.sha1, data, size, type);
617                 free(data);
618                 if (verbose)
619                         percent = display_progress(nr_resolved_deltas,
620                                                    nr_deltas, percent);
621         }
622         free(sorted_by_pos);
623         if (verbose)
624                 fputc('\n', stderr);
625 }
626
627 static void readjust_pack_header_and_sha1(unsigned char *sha1)
628 {
629         struct pack_header hdr;
630         SHA_CTX ctx;
631         int size;
632
633         /* Rewrite pack header with updated object number */
634         if (lseek(output_fd, 0, SEEK_SET) != 0)
635                 die("cannot seek back: %s", strerror(errno));
636         if (read_in_full(output_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
637                 die("cannot read pack header back: %s", strerror(errno));
638         hdr.hdr_entries = htonl(nr_objects);
639         if (lseek(output_fd, 0, SEEK_SET) != 0)
640                 die("cannot seek back: %s", strerror(errno));
641         write_or_die(output_fd, &hdr, sizeof(hdr));
642         if (lseek(output_fd, 0, SEEK_SET) != 0)
643                 die("cannot seek back: %s", strerror(errno));
644
645         /* Recompute and store the new pack's SHA1 */
646         SHA1_Init(&ctx);
647         do {
648                 unsigned char *buf[4096];
649                 size = xread(output_fd, buf, sizeof(buf));
650                 if (size < 0)
651                         die("cannot read pack data back: %s", strerror(errno));
652                 SHA1_Update(&ctx, buf, size);
653         } while (size > 0);
654         SHA1_Final(sha1, &ctx);
655         write_or_die(output_fd, sha1, 20);
656 }
657
658 static int sha1_compare(const void *_a, const void *_b)
659 {
660         struct object_entry *a = *(struct object_entry **)_a;
661         struct object_entry *b = *(struct object_entry **)_b;
662         return hashcmp(a->sha1, b->sha1);
663 }
664
665 /*
666  * On entry *sha1 contains the pack content SHA1 hash, on exit it is
667  * the SHA1 hash of sorted object names.
668  */
669 static const char *write_index_file(const char *index_name, unsigned char *sha1)
670 {
671         struct sha1file *f;
672         struct object_entry **sorted_by_sha, **list, **last;
673         unsigned int array[256];
674         int i, fd;
675         SHA_CTX ctx;
676
677         if (nr_objects) {
678                 sorted_by_sha =
679                         xcalloc(nr_objects, sizeof(struct object_entry *));
680                 list = sorted_by_sha;
681                 last = sorted_by_sha + nr_objects;
682                 for (i = 0; i < nr_objects; ++i)
683                         sorted_by_sha[i] = &objects[i];
684                 qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
685                       sha1_compare);
686
687         }
688         else
689                 sorted_by_sha = list = last = NULL;
690
691         if (!index_name) {
692                 static char tmpfile[PATH_MAX];
693                 snprintf(tmpfile, sizeof(tmpfile),
694                          "%s/tmp_idx_XXXXXX", get_object_directory());
695                 fd = mkstemp(tmpfile);
696                 index_name = xstrdup(tmpfile);
697         } else {
698                 unlink(index_name);
699                 fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
700         }
701         if (fd < 0)
702                 die("unable to create %s: %s", index_name, strerror(errno));
703         f = sha1fd(fd, index_name);
704
705         /*
706          * Write the first-level table (the list is sorted,
707          * but we use a 256-entry lookup to be able to avoid
708          * having to do eight extra binary search iterations).
709          */
710         for (i = 0; i < 256; i++) {
711                 struct object_entry **next = list;
712                 while (next < last) {
713                         struct object_entry *obj = *next;
714                         if (obj->sha1[0] != i)
715                                 break;
716                         next++;
717                 }
718                 array[i] = htonl(next - sorted_by_sha);
719                 list = next;
720         }
721         sha1write(f, array, 256 * sizeof(int));
722
723         /* recompute the SHA1 hash of sorted object names.
724          * currently pack-objects does not do this, but that
725          * can be fixed.
726          */
727         SHA1_Init(&ctx);
728         /*
729          * Write the actual SHA1 entries..
730          */
731         list = sorted_by_sha;
732         for (i = 0; i < nr_objects; i++) {
733                 struct object_entry *obj = *list++;
734                 unsigned int offset = htonl(obj->offset);
735                 sha1write(f, &offset, 4);
736                 sha1write(f, obj->sha1, 20);
737                 SHA1_Update(&ctx, obj->sha1, 20);
738         }
739         sha1write(f, sha1, 20);
740         sha1close(f, NULL, 1);
741         free(sorted_by_sha);
742         SHA1_Final(sha1, &ctx);
743         return index_name;
744 }
745
746 static void final(const char *final_pack_name, const char *curr_pack_name,
747                   const char *final_index_name, const char *curr_index_name,
748                   const char *keep_name, const char *keep_msg,
749                   unsigned char *sha1)
750 {
751         const char *report = "pack";
752         char name[PATH_MAX];
753         int err;
754
755         if (!from_stdin) {
756                 close(input_fd);
757         } else {
758                 err = close(output_fd);
759                 if (err)
760                         die("error while closing pack file: %s", strerror(errno));
761                 chmod(curr_pack_name, 0444);
762         }
763
764         if (keep_msg) {
765                 int keep_fd, keep_msg_len = strlen(keep_msg);
766                 if (!keep_name) {
767                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
768                                  get_object_directory(), sha1_to_hex(sha1));
769                         keep_name = name;
770                 }
771                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
772                 if (keep_fd < 0) {
773                         if (errno != EEXIST)
774                                 die("cannot write keep file");
775                 } else {
776                         if (keep_msg_len > 0) {
777                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
778                                 write_or_die(keep_fd, "\n", 1);
779                         }
780                         close(keep_fd);
781                         report = "keep";
782                 }
783         }
784
785         if (final_pack_name != curr_pack_name) {
786                 if (!final_pack_name) {
787                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
788                                  get_object_directory(), sha1_to_hex(sha1));
789                         final_pack_name = name;
790                 }
791                 if (move_temp_to_file(curr_pack_name, final_pack_name))
792                         die("cannot store pack file");
793         }
794
795         chmod(curr_index_name, 0444);
796         if (final_index_name != curr_index_name) {
797                 if (!final_index_name) {
798                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
799                                  get_object_directory(), sha1_to_hex(sha1));
800                         final_index_name = name;
801                 }
802                 if (move_temp_to_file(curr_index_name, final_index_name))
803                         die("cannot store index file");
804         }
805
806         if (!from_stdin) {
807                 printf("%s\n", sha1_to_hex(sha1));
808         } else {
809                 char buf[48];
810                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
811                                    report, sha1_to_hex(sha1));
812                 write_or_die(1, buf, len);
813
814                 /*
815                  * Let's just mimic git-unpack-objects here and write
816                  * the last part of the input buffer to stdout.
817                  */
818                 while (input_len) {
819                         err = xwrite(1, input_buffer + input_offset, input_len);
820                         if (err <= 0)
821                                 break;
822                         input_len -= err;
823                         input_offset += err;
824                 }
825         }
826 }
827
828 int main(int argc, char **argv)
829 {
830         int i, fix_thin_pack = 0;
831         const char *curr_pack, *pack_name = NULL;
832         const char *curr_index, *index_name = NULL;
833         const char *keep_name = NULL, *keep_msg = NULL;
834         char *index_name_buf = NULL, *keep_name_buf = NULL;
835         unsigned char sha1[20];
836
837         for (i = 1; i < argc; i++) {
838                 const char *arg = argv[i];
839
840                 if (*arg == '-') {
841                         if (!strcmp(arg, "--stdin")) {
842                                 from_stdin = 1;
843                         } else if (!strcmp(arg, "--fix-thin")) {
844                                 fix_thin_pack = 1;
845                         } else if (!strcmp(arg, "--keep")) {
846                                 keep_msg = "";
847                         } else if (!prefixcmp(arg, "--keep=")) {
848                                 keep_msg = arg + 7;
849                         } else if (!prefixcmp(arg, "--pack_header=")) {
850                                 struct pack_header *hdr;
851                                 char *c;
852
853                                 hdr = (struct pack_header *)input_buffer;
854                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
855                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
856                                 if (*c != ',')
857                                         die("bad %s", arg);
858                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
859                                 if (*c)
860                                         die("bad %s", arg);
861                                 input_len = sizeof(*hdr);
862                         } else if (!strcmp(arg, "-v")) {
863                                 verbose = 1;
864                         } else if (!strcmp(arg, "-o")) {
865                                 if (index_name || (i+1) >= argc)
866                                         usage(index_pack_usage);
867                                 index_name = argv[++i];
868                         } else
869                                 usage(index_pack_usage);
870                         continue;
871                 }
872
873                 if (pack_name)
874                         usage(index_pack_usage);
875                 pack_name = arg;
876         }
877
878         if (!pack_name && !from_stdin)
879                 usage(index_pack_usage);
880         if (fix_thin_pack && !from_stdin)
881                 die("--fix-thin cannot be used without --stdin");
882         if (!index_name && pack_name) {
883                 int len = strlen(pack_name);
884                 if (!has_extension(pack_name, ".pack"))
885                         die("packfile name '%s' does not end with '.pack'",
886                             pack_name);
887                 index_name_buf = xmalloc(len);
888                 memcpy(index_name_buf, pack_name, len - 5);
889                 strcpy(index_name_buf + len - 5, ".idx");
890                 index_name = index_name_buf;
891         }
892         if (keep_msg && !keep_name && pack_name) {
893                 int len = strlen(pack_name);
894                 if (!has_extension(pack_name, ".pack"))
895                         die("packfile name '%s' does not end with '.pack'",
896                             pack_name);
897                 keep_name_buf = xmalloc(len);
898                 memcpy(keep_name_buf, pack_name, len - 5);
899                 strcpy(keep_name_buf + len - 5, ".keep");
900                 keep_name = keep_name_buf;
901         }
902
903         curr_pack = open_pack_file(pack_name);
904         parse_pack_header();
905         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
906         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
907         if (verbose)
908                 setup_progress_signal();
909         parse_pack_objects(sha1);
910         if (nr_deltas != nr_resolved_deltas) {
911                 if (fix_thin_pack) {
912                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
913                         int nr_objects_initial = nr_objects;
914                         if (nr_unresolved <= 0)
915                                 die("confusion beyond insanity");
916                         objects = xrealloc(objects,
917                                            (nr_objects + nr_unresolved + 1)
918                                            * sizeof(*objects));
919                         fix_unresolved_deltas(nr_unresolved);
920                         if (verbose)
921                                 fprintf(stderr, "%d objects were added to complete this thin pack.\n",
922                                         nr_objects - nr_objects_initial);
923                         readjust_pack_header_and_sha1(sha1);
924                 }
925                 if (nr_deltas != nr_resolved_deltas)
926                         die("pack has %d unresolved deltas",
927                             nr_deltas - nr_resolved_deltas);
928         } else {
929                 /* Flush remaining pack final 20-byte SHA1. */
930                 flush();
931         }
932         free(deltas);
933         curr_index = write_index_file(index_name, sha1);
934         final(pack_name, curr_pack,
935                 index_name, curr_index,
936                 keep_name, keep_msg,
937                 sha1);
938         free(objects);
939         free(index_name_buf);
940         free(keep_name_buf);
941
942         return 0;
943 }