fix pread()'s short read in index-pack
[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 #include "progress.h"
10 #include "fsck.h"
11
12 static const char index_pack_usage[] =
13 "git index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] [--strict] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
14
15 struct object_entry
16 {
17         struct pack_idx_entry idx;
18         unsigned long size;
19         unsigned int hdr_size;
20         enum object_type type;
21         enum object_type real_type;
22 };
23
24 union delta_base {
25         unsigned char sha1[20];
26         off_t offset;
27 };
28
29 struct base_data {
30         struct base_data *base;
31         struct base_data *child;
32         struct object_entry *obj;
33         void *data;
34         unsigned long size;
35 };
36
37 /*
38  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
39  * to memcmp() only the first 20 bytes.
40  */
41 #define UNION_BASE_SZ   20
42
43 #define FLAG_LINK (1u<<20)
44 #define FLAG_CHECKED (1u<<21)
45
46 struct delta_entry
47 {
48         union delta_base base;
49         int obj_no;
50 };
51
52 static struct object_entry *objects;
53 static struct delta_entry *deltas;
54 static struct base_data *base_cache;
55 static size_t base_cache_used;
56 static int nr_objects;
57 static int nr_deltas;
58 static int nr_resolved_deltas;
59
60 static int from_stdin;
61 static int strict;
62 static int verbose;
63
64 static struct progress *progress;
65
66 /* We always read in 4kB chunks. */
67 static unsigned char input_buffer[4096];
68 static unsigned int input_offset, input_len;
69 static off_t consumed_bytes;
70 static SHA_CTX input_ctx;
71 static uint32_t input_crc32;
72 static int input_fd, output_fd, pack_fd;
73
74 static int mark_link(struct object *obj, int type, void *data)
75 {
76         if (!obj)
77                 return -1;
78
79         if (type != OBJ_ANY && obj->type != type)
80                 die("object type mismatch at %s", sha1_to_hex(obj->sha1));
81
82         obj->flags |= FLAG_LINK;
83         return 0;
84 }
85
86 /* The content of each linked object must have been checked
87    or it must be already present in the object database */
88 static void check_object(struct object *obj)
89 {
90         if (!obj)
91                 return;
92
93         if (!(obj->flags & FLAG_LINK))
94                 return;
95
96         if (!(obj->flags & FLAG_CHECKED)) {
97                 unsigned long size;
98                 int type = sha1_object_info(obj->sha1, &size);
99                 if (type != obj->type || type <= 0)
100                         die("object of unexpected type");
101                 obj->flags |= FLAG_CHECKED;
102                 return;
103         }
104 }
105
106 static void check_objects(void)
107 {
108         unsigned i, max;
109
110         max = get_max_object_index();
111         for (i = 0; i < max; i++)
112                 check_object(get_indexed_object(i));
113 }
114
115
116 /* Discard current buffer used content. */
117 static void flush(void)
118 {
119         if (input_offset) {
120                 if (output_fd >= 0)
121                         write_or_die(output_fd, input_buffer, input_offset);
122                 SHA1_Update(&input_ctx, input_buffer, input_offset);
123                 memmove(input_buffer, input_buffer + input_offset, input_len);
124                 input_offset = 0;
125         }
126 }
127
128 /*
129  * Make sure at least "min" bytes are available in the buffer, and
130  * return the pointer to the buffer.
131  */
132 static void *fill(int min)
133 {
134         if (min <= input_len)
135                 return input_buffer + input_offset;
136         if (min > sizeof(input_buffer))
137                 die("cannot fill %d bytes", min);
138         flush();
139         do {
140                 ssize_t ret = xread(input_fd, input_buffer + input_len,
141                                 sizeof(input_buffer) - input_len);
142                 if (ret <= 0) {
143                         if (!ret)
144                                 die("early EOF");
145                         die("read error on input: %s", strerror(errno));
146                 }
147                 input_len += ret;
148                 if (from_stdin)
149                         display_throughput(progress, consumed_bytes + input_len);
150         } while (input_len < min);
151         return input_buffer;
152 }
153
154 static void use(int bytes)
155 {
156         if (bytes > input_len)
157                 die("used more bytes than were available");
158         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
159         input_len -= bytes;
160         input_offset += bytes;
161
162         /* make sure off_t is sufficiently large not to wrap */
163         if (consumed_bytes > consumed_bytes + bytes)
164                 die("pack too large for current definition of off_t");
165         consumed_bytes += bytes;
166 }
167
168 static char *open_pack_file(char *pack_name)
169 {
170         if (from_stdin) {
171                 input_fd = 0;
172                 if (!pack_name) {
173                         static char tmpfile[PATH_MAX];
174                         snprintf(tmpfile, sizeof(tmpfile),
175                                  "%s/pack/tmp_pack_XXXXXX", get_object_directory());
176                         output_fd = xmkstemp(tmpfile);
177                         pack_name = xstrdup(tmpfile);
178                 } else
179                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
180                 if (output_fd < 0)
181                         die("unable to create %s: %s\n", pack_name, strerror(errno));
182                 pack_fd = output_fd;
183         } else {
184                 input_fd = open(pack_name, O_RDONLY);
185                 if (input_fd < 0)
186                         die("cannot open packfile '%s': %s",
187                             pack_name, strerror(errno));
188                 output_fd = -1;
189                 pack_fd = input_fd;
190         }
191         SHA1_Init(&input_ctx);
192         return pack_name;
193 }
194
195 static void parse_pack_header(void)
196 {
197         struct pack_header *hdr = fill(sizeof(struct pack_header));
198
199         /* Header consistency check */
200         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
201                 die("pack signature mismatch");
202         if (!pack_version_ok(hdr->hdr_version))
203                 die("pack version %"PRIu32" unsupported",
204                         ntohl(hdr->hdr_version));
205
206         nr_objects = ntohl(hdr->hdr_entries);
207         use(sizeof(struct pack_header));
208 }
209
210 static void bad_object(unsigned long offset, const char *format,
211                        ...) NORETURN __attribute__((format (printf, 2, 3)));
212
213 static void bad_object(unsigned long offset, const char *format, ...)
214 {
215         va_list params;
216         char buf[1024];
217
218         va_start(params, format);
219         vsnprintf(buf, sizeof(buf), format, params);
220         va_end(params);
221         die("pack has bad object at offset %lu: %s", offset, buf);
222 }
223
224 static void prune_base_data(struct base_data *retain)
225 {
226         struct base_data *b = base_cache;
227         for (b = base_cache;
228              base_cache_used > delta_base_cache_limit && b;
229              b = b->child) {
230                 if (b->data && b != retain) {
231                         free(b->data);
232                         b->data = NULL;
233                         base_cache_used -= b->size;
234                 }
235         }
236 }
237
238 static void link_base_data(struct base_data *base, struct base_data *c)
239 {
240         if (base)
241                 base->child = c;
242         else
243                 base_cache = c;
244
245         c->base = base;
246         c->child = NULL;
247         base_cache_used += c->size;
248         prune_base_data(c);
249 }
250
251 static void unlink_base_data(struct base_data *c)
252 {
253         struct base_data *base = c->base;
254         if (base)
255                 base->child = NULL;
256         else
257                 base_cache = NULL;
258         if (c->data) {
259                 free(c->data);
260                 base_cache_used -= c->size;
261         }
262 }
263
264 static void *unpack_entry_data(unsigned long offset, unsigned long size)
265 {
266         z_stream stream;
267         void *buf = xmalloc(size);
268
269         memset(&stream, 0, sizeof(stream));
270         stream.next_out = buf;
271         stream.avail_out = size;
272         stream.next_in = fill(1);
273         stream.avail_in = input_len;
274         inflateInit(&stream);
275
276         for (;;) {
277                 int ret = inflate(&stream, 0);
278                 use(input_len - stream.avail_in);
279                 if (stream.total_out == size && ret == Z_STREAM_END)
280                         break;
281                 if (ret != Z_OK)
282                         bad_object(offset, "inflate returned %d", ret);
283                 stream.next_in = fill(1);
284                 stream.avail_in = input_len;
285         }
286         inflateEnd(&stream);
287         return buf;
288 }
289
290 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
291 {
292         unsigned char *p, c;
293         unsigned long size;
294         off_t base_offset;
295         unsigned shift;
296         void *data;
297
298         obj->idx.offset = consumed_bytes;
299         input_crc32 = crc32(0, Z_NULL, 0);
300
301         p = fill(1);
302         c = *p;
303         use(1);
304         obj->type = (c >> 4) & 7;
305         size = (c & 15);
306         shift = 4;
307         while (c & 0x80) {
308                 p = fill(1);
309                 c = *p;
310                 use(1);
311                 size += (c & 0x7fUL) << shift;
312                 shift += 7;
313         }
314         obj->size = size;
315
316         switch (obj->type) {
317         case OBJ_REF_DELTA:
318                 hashcpy(delta_base->sha1, fill(20));
319                 use(20);
320                 break;
321         case OBJ_OFS_DELTA:
322                 memset(delta_base, 0, sizeof(*delta_base));
323                 p = fill(1);
324                 c = *p;
325                 use(1);
326                 base_offset = c & 127;
327                 while (c & 128) {
328                         base_offset += 1;
329                         if (!base_offset || MSB(base_offset, 7))
330                                 bad_object(obj->idx.offset, "offset value overflow for delta base object");
331                         p = fill(1);
332                         c = *p;
333                         use(1);
334                         base_offset = (base_offset << 7) + (c & 127);
335                 }
336                 delta_base->offset = obj->idx.offset - base_offset;
337                 if (delta_base->offset >= obj->idx.offset)
338                         bad_object(obj->idx.offset, "delta base offset is out of bound");
339                 break;
340         case OBJ_COMMIT:
341         case OBJ_TREE:
342         case OBJ_BLOB:
343         case OBJ_TAG:
344                 break;
345         default:
346                 bad_object(obj->idx.offset, "unknown object type %d", obj->type);
347         }
348         obj->hdr_size = consumed_bytes - obj->idx.offset;
349
350         data = unpack_entry_data(obj->idx.offset, obj->size);
351         obj->idx.crc32 = input_crc32;
352         return data;
353 }
354
355 static void *get_data_from_pack(struct object_entry *obj)
356 {
357         off_t from = obj[0].idx.offset + obj[0].hdr_size;
358         unsigned long len = obj[1].idx.offset - from;
359         unsigned long rdy = 0;
360         unsigned char *src, *data;
361         z_stream stream;
362         int st;
363
364         src = xmalloc(len);
365         data = src;
366         do {
367                 ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
368                 if (n < 0)
369                         die("cannot pread pack file: %s", strerror(errno));
370                 if (!n)
371                         die("premature end of pack file, %lu bytes missing",
372                             len - rdy);
373                 rdy += n;
374         } while (rdy < len);
375         data = xmalloc(obj->size);
376         memset(&stream, 0, sizeof(stream));
377         stream.next_out = data;
378         stream.avail_out = obj->size;
379         stream.next_in = src;
380         stream.avail_in = len;
381         inflateInit(&stream);
382         while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
383         inflateEnd(&stream);
384         if (st != Z_STREAM_END || stream.total_out != obj->size)
385                 die("serious inflate inconsistency");
386         free(src);
387         return data;
388 }
389
390 static int find_delta(const union delta_base *base)
391 {
392         int first = 0, last = nr_deltas;
393
394         while (first < last) {
395                 int next = (first + last) / 2;
396                 struct delta_entry *delta = &deltas[next];
397                 int cmp;
398
399                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
400                 if (!cmp)
401                         return next;
402                 if (cmp < 0) {
403                         last = next;
404                         continue;
405                 }
406                 first = next+1;
407         }
408         return -first-1;
409 }
410
411 static int find_delta_children(const union delta_base *base,
412                                int *first_index, int *last_index)
413 {
414         int first = find_delta(base);
415         int last = first;
416         int end = nr_deltas - 1;
417
418         if (first < 0)
419                 return -1;
420         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
421                 --first;
422         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
423                 ++last;
424         *first_index = first;
425         *last_index = last;
426         return 0;
427 }
428
429 static void sha1_object(const void *data, unsigned long size,
430                         enum object_type type, unsigned char *sha1)
431 {
432         hash_sha1_file(data, size, typename(type), sha1);
433         if (has_sha1_file(sha1)) {
434                 void *has_data;
435                 enum object_type has_type;
436                 unsigned long has_size;
437                 has_data = read_sha1_file(sha1, &has_type, &has_size);
438                 if (!has_data)
439                         die("cannot read existing object %s", sha1_to_hex(sha1));
440                 if (size != has_size || type != has_type ||
441                     memcmp(data, has_data, size) != 0)
442                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
443                 free(has_data);
444         }
445         if (strict) {
446                 if (type == OBJ_BLOB) {
447                         struct blob *blob = lookup_blob(sha1);
448                         if (blob)
449                                 blob->object.flags |= FLAG_CHECKED;
450                         else
451                                 die("invalid blob object %s", sha1_to_hex(sha1));
452                 } else {
453                         struct object *obj;
454                         int eaten;
455                         void *buf = (void *) data;
456
457                         /*
458                          * we do not need to free the memory here, as the
459                          * buf is deleted by the caller.
460                          */
461                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
462                         if (!obj)
463                                 die("invalid %s", typename(type));
464                         if (fsck_object(obj, 1, fsck_error_function))
465                                 die("Error in object");
466                         if (fsck_walk(obj, mark_link, 0))
467                                 die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
468
469                         if (obj->type == OBJ_TREE) {
470                                 struct tree *item = (struct tree *) obj;
471                                 item->buffer = NULL;
472                         }
473                         if (obj->type == OBJ_COMMIT) {
474                                 struct commit *commit = (struct commit *) obj;
475                                 commit->buffer = NULL;
476                         }
477                         obj->flags |= FLAG_CHECKED;
478                 }
479         }
480 }
481
482 static void *get_base_data(struct base_data *c)
483 {
484         if (!c->data) {
485                 struct object_entry *obj = c->obj;
486
487                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
488                         void *base = get_base_data(c->base);
489                         void *raw = get_data_from_pack(obj);
490                         c->data = patch_delta(
491                                 base, c->base->size,
492                                 raw, obj->size,
493                                 &c->size);
494                         free(raw);
495                         if (!c->data)
496                                 bad_object(obj->idx.offset, "failed to apply delta");
497                 } else
498                         c->data = get_data_from_pack(obj);
499
500                 base_cache_used += c->size;
501                 prune_base_data(c);
502         }
503         return c->data;
504 }
505
506 static void resolve_delta(struct object_entry *delta_obj,
507                           struct base_data *base_obj, enum object_type type)
508 {
509         void *delta_data;
510         unsigned long delta_size;
511         union delta_base delta_base;
512         int j, first, last;
513         struct base_data result;
514
515         delta_obj->real_type = type;
516         delta_data = get_data_from_pack(delta_obj);
517         delta_size = delta_obj->size;
518         result.data = patch_delta(get_base_data(base_obj), base_obj->size,
519                              delta_data, delta_size,
520                              &result.size);
521         free(delta_data);
522         if (!result.data)
523                 bad_object(delta_obj->idx.offset, "failed to apply delta");
524         sha1_object(result.data, result.size, type, delta_obj->idx.sha1);
525         nr_resolved_deltas++;
526
527         result.obj = delta_obj;
528         link_base_data(base_obj, &result);
529
530         hashcpy(delta_base.sha1, delta_obj->idx.sha1);
531         if (!find_delta_children(&delta_base, &first, &last)) {
532                 for (j = first; j <= last; j++) {
533                         struct object_entry *child = objects + deltas[j].obj_no;
534                         if (child->real_type == OBJ_REF_DELTA)
535                                 resolve_delta(child, &result, type);
536                 }
537         }
538
539         memset(&delta_base, 0, sizeof(delta_base));
540         delta_base.offset = delta_obj->idx.offset;
541         if (!find_delta_children(&delta_base, &first, &last)) {
542                 for (j = first; j <= last; j++) {
543                         struct object_entry *child = objects + deltas[j].obj_no;
544                         if (child->real_type == OBJ_OFS_DELTA)
545                                 resolve_delta(child, &result, type);
546                 }
547         }
548
549         unlink_base_data(&result);
550 }
551
552 static int compare_delta_entry(const void *a, const void *b)
553 {
554         const struct delta_entry *delta_a = a;
555         const struct delta_entry *delta_b = b;
556         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
557 }
558
559 /* Parse all objects and return the pack content SHA1 hash */
560 static void parse_pack_objects(unsigned char *sha1)
561 {
562         int i;
563         struct delta_entry *delta = deltas;
564         struct stat st;
565
566         /*
567          * First pass:
568          * - find locations of all objects;
569          * - calculate SHA1 of all non-delta objects;
570          * - remember base (SHA1 or offset) for all deltas.
571          */
572         if (verbose)
573                 progress = start_progress(
574                                 from_stdin ? "Receiving objects" : "Indexing objects",
575                                 nr_objects);
576         for (i = 0; i < nr_objects; i++) {
577                 struct object_entry *obj = &objects[i];
578                 void *data = unpack_raw_entry(obj, &delta->base);
579                 obj->real_type = obj->type;
580                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
581                         nr_deltas++;
582                         delta->obj_no = i;
583                         delta++;
584                 } else
585                         sha1_object(data, obj->size, obj->type, obj->idx.sha1);
586                 free(data);
587                 display_progress(progress, i+1);
588         }
589         objects[i].idx.offset = consumed_bytes;
590         stop_progress(&progress);
591
592         /* Check pack integrity */
593         flush();
594         SHA1_Final(sha1, &input_ctx);
595         if (hashcmp(fill(20), sha1))
596                 die("pack is corrupted (SHA1 mismatch)");
597         use(20);
598
599         /* If input_fd is a file, we should have reached its end now. */
600         if (fstat(input_fd, &st))
601                 die("cannot fstat packfile: %s", strerror(errno));
602         if (S_ISREG(st.st_mode) &&
603                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
604                 die("pack has junk at the end");
605
606         if (!nr_deltas)
607                 return;
608
609         /* Sort deltas by base SHA1/offset for fast searching */
610         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
611               compare_delta_entry);
612
613         /*
614          * Second pass:
615          * - for all non-delta objects, look if it is used as a base for
616          *   deltas;
617          * - if used as a base, uncompress the object and apply all deltas,
618          *   recursively checking if the resulting object is used as a base
619          *   for some more deltas.
620          */
621         if (verbose)
622                 progress = start_progress("Resolving deltas", nr_deltas);
623         for (i = 0; i < nr_objects; i++) {
624                 struct object_entry *obj = &objects[i];
625                 union delta_base base;
626                 int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
627                 struct base_data base_obj;
628
629                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
630                         continue;
631                 hashcpy(base.sha1, obj->idx.sha1);
632                 ref = !find_delta_children(&base, &ref_first, &ref_last);
633                 memset(&base, 0, sizeof(base));
634                 base.offset = obj->idx.offset;
635                 ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
636                 if (!ref && !ofs)
637                         continue;
638                 base_obj.data = get_data_from_pack(obj);
639                 base_obj.size = obj->size;
640                 base_obj.obj = obj;
641                 link_base_data(NULL, &base_obj);
642
643                 if (ref)
644                         for (j = ref_first; j <= ref_last; j++) {
645                                 struct object_entry *child = objects + deltas[j].obj_no;
646                                 if (child->real_type == OBJ_REF_DELTA)
647                                         resolve_delta(child, &base_obj, obj->type);
648                         }
649                 if (ofs)
650                         for (j = ofs_first; j <= ofs_last; j++) {
651                                 struct object_entry *child = objects + deltas[j].obj_no;
652                                 if (child->real_type == OBJ_OFS_DELTA)
653                                         resolve_delta(child, &base_obj, obj->type);
654                         }
655                 unlink_base_data(&base_obj);
656                 display_progress(progress, nr_resolved_deltas);
657         }
658 }
659
660 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
661 {
662         z_stream stream;
663         unsigned long maxsize;
664         void *out;
665
666         memset(&stream, 0, sizeof(stream));
667         deflateInit(&stream, zlib_compression_level);
668         maxsize = deflateBound(&stream, size);
669         out = xmalloc(maxsize);
670
671         /* Compress it */
672         stream.next_in = in;
673         stream.avail_in = size;
674         stream.next_out = out;
675         stream.avail_out = maxsize;
676         while (deflate(&stream, Z_FINISH) == Z_OK);
677         deflateEnd(&stream);
678
679         size = stream.total_out;
680         sha1write(f, out, size);
681         free(out);
682         return size;
683 }
684
685 static struct object_entry *append_obj_to_pack(struct sha1file *f,
686                                const unsigned char *sha1, void *buf,
687                                unsigned long size, enum object_type type)
688 {
689         struct object_entry *obj = &objects[nr_objects++];
690         unsigned char header[10];
691         unsigned long s = size;
692         int n = 0;
693         unsigned char c = (type << 4) | (s & 15);
694         s >>= 4;
695         while (s) {
696                 header[n++] = c | 0x80;
697                 c = s & 0x7f;
698                 s >>= 7;
699         }
700         header[n++] = c;
701         crc32_begin(f);
702         sha1write(f, header, n);
703         obj[0].size = size;
704         obj[0].hdr_size = n;
705         obj[0].type = type;
706         obj[0].real_type = type;
707         obj[1].idx.offset = obj[0].idx.offset + n;
708         obj[1].idx.offset += write_compressed(f, buf, size);
709         obj[0].idx.crc32 = crc32_end(f);
710         sha1flush(f);
711         hashcpy(obj->idx.sha1, sha1);
712         return obj;
713 }
714
715 static int delta_pos_compare(const void *_a, const void *_b)
716 {
717         struct delta_entry *a = *(struct delta_entry **)_a;
718         struct delta_entry *b = *(struct delta_entry **)_b;
719         return a->obj_no - b->obj_no;
720 }
721
722 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
723 {
724         struct delta_entry **sorted_by_pos;
725         int i, n = 0;
726
727         /*
728          * Since many unresolved deltas may well be themselves base objects
729          * for more unresolved deltas, we really want to include the
730          * smallest number of base objects that would cover as much delta
731          * as possible by picking the
732          * trunc deltas first, allowing for other deltas to resolve without
733          * additional base objects.  Since most base objects are to be found
734          * before deltas depending on them, a good heuristic is to start
735          * resolving deltas in the same order as their position in the pack.
736          */
737         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
738         for (i = 0; i < nr_deltas; i++) {
739                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
740                         continue;
741                 sorted_by_pos[n++] = &deltas[i];
742         }
743         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
744
745         for (i = 0; i < n; i++) {
746                 struct delta_entry *d = sorted_by_pos[i];
747                 enum object_type type;
748                 int j, first, last;
749                 struct base_data base_obj;
750
751                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
752                         continue;
753                 base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
754                 if (!base_obj.data)
755                         continue;
756
757                 if (check_sha1_signature(d->base.sha1, base_obj.data,
758                                 base_obj.size, typename(type)))
759                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
760                 base_obj.obj = append_obj_to_pack(f, d->base.sha1,
761                                         base_obj.data, base_obj.size, type);
762                 link_base_data(NULL, &base_obj);
763
764                 find_delta_children(&d->base, &first, &last);
765                 for (j = first; j <= last; j++) {
766                         struct object_entry *child = objects + deltas[j].obj_no;
767                         if (child->real_type == OBJ_REF_DELTA)
768                                 resolve_delta(child, &base_obj, type);
769                 }
770
771                 unlink_base_data(&base_obj);
772                 display_progress(progress, nr_resolved_deltas);
773         }
774         free(sorted_by_pos);
775 }
776
777 static void final(const char *final_pack_name, const char *curr_pack_name,
778                   const char *final_index_name, const char *curr_index_name,
779                   const char *keep_name, const char *keep_msg,
780                   unsigned char *sha1)
781 {
782         const char *report = "pack";
783         char name[PATH_MAX];
784         int err;
785
786         if (!from_stdin) {
787                 close(input_fd);
788         } else {
789                 fsync_or_die(output_fd, curr_pack_name);
790                 err = close(output_fd);
791                 if (err)
792                         die("error while closing pack file: %s", strerror(errno));
793                 chmod(curr_pack_name, 0444);
794         }
795
796         if (keep_msg) {
797                 int keep_fd, keep_msg_len = strlen(keep_msg);
798                 if (!keep_name) {
799                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
800                                  get_object_directory(), sha1_to_hex(sha1));
801                         keep_name = name;
802                 }
803                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
804                 if (keep_fd < 0) {
805                         if (errno != EEXIST)
806                                 die("cannot write keep file");
807                 } else {
808                         if (keep_msg_len > 0) {
809                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
810                                 write_or_die(keep_fd, "\n", 1);
811                         }
812                         if (close(keep_fd) != 0)
813                                 die("cannot write keep file");
814                         report = "keep";
815                 }
816         }
817
818         if (final_pack_name != curr_pack_name) {
819                 if (!final_pack_name) {
820                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
821                                  get_object_directory(), sha1_to_hex(sha1));
822                         final_pack_name = name;
823                 }
824                 if (move_temp_to_file(curr_pack_name, final_pack_name))
825                         die("cannot store pack file");
826         }
827
828         chmod(curr_index_name, 0444);
829         if (final_index_name != curr_index_name) {
830                 if (!final_index_name) {
831                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
832                                  get_object_directory(), sha1_to_hex(sha1));
833                         final_index_name = name;
834                 }
835                 if (move_temp_to_file(curr_index_name, final_index_name))
836                         die("cannot store index file");
837         }
838
839         if (!from_stdin) {
840                 printf("%s\n", sha1_to_hex(sha1));
841         } else {
842                 char buf[48];
843                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
844                                    report, sha1_to_hex(sha1));
845                 write_or_die(1, buf, len);
846
847                 /*
848                  * Let's just mimic git-unpack-objects here and write
849                  * the last part of the input buffer to stdout.
850                  */
851                 while (input_len) {
852                         err = xwrite(1, input_buffer + input_offset, input_len);
853                         if (err <= 0)
854                                 break;
855                         input_len -= err;
856                         input_offset += err;
857                 }
858         }
859 }
860
861 static int git_index_pack_config(const char *k, const char *v, void *cb)
862 {
863         if (!strcmp(k, "pack.indexversion")) {
864                 pack_idx_default_version = git_config_int(k, v);
865                 if (pack_idx_default_version > 2)
866                         die("bad pack.indexversion=%"PRIu32,
867                                 pack_idx_default_version);
868                 return 0;
869         }
870         return git_default_config(k, v, cb);
871 }
872
873 int main(int argc, char **argv)
874 {
875         int i, fix_thin_pack = 0;
876         char *curr_pack, *pack_name = NULL;
877         char *curr_index, *index_name = NULL;
878         const char *keep_name = NULL, *keep_msg = NULL;
879         char *index_name_buf = NULL, *keep_name_buf = NULL;
880         struct pack_idx_entry **idx_objects;
881         unsigned char pack_sha1[20];
882         int nongit = 0;
883
884         setup_git_directory_gently(&nongit);
885         git_config(git_index_pack_config, NULL);
886
887         for (i = 1; i < argc; i++) {
888                 char *arg = argv[i];
889
890                 if (*arg == '-') {
891                         if (!strcmp(arg, "--stdin")) {
892                                 from_stdin = 1;
893                         } else if (!strcmp(arg, "--fix-thin")) {
894                                 fix_thin_pack = 1;
895                         } else if (!strcmp(arg, "--strict")) {
896                                 strict = 1;
897                         } else if (!strcmp(arg, "--keep")) {
898                                 keep_msg = "";
899                         } else if (!prefixcmp(arg, "--keep=")) {
900                                 keep_msg = arg + 7;
901                         } else if (!prefixcmp(arg, "--pack_header=")) {
902                                 struct pack_header *hdr;
903                                 char *c;
904
905                                 hdr = (struct pack_header *)input_buffer;
906                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
907                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
908                                 if (*c != ',')
909                                         die("bad %s", arg);
910                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
911                                 if (*c)
912                                         die("bad %s", arg);
913                                 input_len = sizeof(*hdr);
914                         } else if (!strcmp(arg, "-v")) {
915                                 verbose = 1;
916                         } else if (!strcmp(arg, "-o")) {
917                                 if (index_name || (i+1) >= argc)
918                                         usage(index_pack_usage);
919                                 index_name = argv[++i];
920                         } else if (!prefixcmp(arg, "--index-version=")) {
921                                 char *c;
922                                 pack_idx_default_version = strtoul(arg + 16, &c, 10);
923                                 if (pack_idx_default_version > 2)
924                                         die("bad %s", arg);
925                                 if (*c == ',')
926                                         pack_idx_off32_limit = strtoul(c+1, &c, 0);
927                                 if (*c || pack_idx_off32_limit & 0x80000000)
928                                         die("bad %s", arg);
929                         } else
930                                 usage(index_pack_usage);
931                         continue;
932                 }
933
934                 if (pack_name)
935                         usage(index_pack_usage);
936                 pack_name = arg;
937         }
938
939         if (!pack_name && !from_stdin)
940                 usage(index_pack_usage);
941         if (fix_thin_pack && !from_stdin)
942                 die("--fix-thin cannot be used without --stdin");
943         if (!index_name && pack_name) {
944                 int len = strlen(pack_name);
945                 if (!has_extension(pack_name, ".pack"))
946                         die("packfile name '%s' does not end with '.pack'",
947                             pack_name);
948                 index_name_buf = xmalloc(len);
949                 memcpy(index_name_buf, pack_name, len - 5);
950                 strcpy(index_name_buf + len - 5, ".idx");
951                 index_name = index_name_buf;
952         }
953         if (keep_msg && !keep_name && pack_name) {
954                 int len = strlen(pack_name);
955                 if (!has_extension(pack_name, ".pack"))
956                         die("packfile name '%s' does not end with '.pack'",
957                             pack_name);
958                 keep_name_buf = xmalloc(len);
959                 memcpy(keep_name_buf, pack_name, len - 5);
960                 strcpy(keep_name_buf + len - 5, ".keep");
961                 keep_name = keep_name_buf;
962         }
963
964         curr_pack = open_pack_file(pack_name);
965         parse_pack_header();
966         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
967         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
968         parse_pack_objects(pack_sha1);
969         if (nr_deltas == nr_resolved_deltas) {
970                 stop_progress(&progress);
971                 /* Flush remaining pack final 20-byte SHA1. */
972                 flush();
973         } else {
974                 if (fix_thin_pack) {
975                         struct sha1file *f;
976                         unsigned char read_sha1[20], tail_sha1[20];
977                         char msg[48];
978                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
979                         int nr_objects_initial = nr_objects;
980                         if (nr_unresolved <= 0)
981                                 die("confusion beyond insanity");
982                         objects = xrealloc(objects,
983                                            (nr_objects + nr_unresolved + 1)
984                                            * sizeof(*objects));
985                         f = sha1fd(output_fd, curr_pack);
986                         fix_unresolved_deltas(f, nr_unresolved);
987                         sprintf(msg, "completed with %d local objects",
988                                 nr_objects - nr_objects_initial);
989                         stop_progress_msg(&progress, msg);
990                         sha1close(f, tail_sha1, 0);
991                         hashcpy(read_sha1, pack_sha1);
992                         fixup_pack_header_footer(output_fd, pack_sha1,
993                                                  curr_pack, nr_objects,
994                                                  read_sha1, consumed_bytes-20);
995                         if (hashcmp(read_sha1, tail_sha1) != 0)
996                                 die("Unexpected tail checksum for %s "
997                                     "(disk corruption?)", curr_pack);
998                 }
999                 if (nr_deltas != nr_resolved_deltas)
1000                         die("pack has %d unresolved deltas",
1001                             nr_deltas - nr_resolved_deltas);
1002         }
1003         free(deltas);
1004         if (strict)
1005                 check_objects();
1006
1007         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1008         for (i = 0; i < nr_objects; i++)
1009                 idx_objects[i] = &objects[i].idx;
1010         curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
1011         free(idx_objects);
1012
1013         final(pack_name, curr_pack,
1014                 index_name, curr_index,
1015                 keep_name, keep_msg,
1016                 pack_sha1);
1017         free(objects);
1018         free(index_name_buf);
1019         free(keep_name_buf);
1020         if (pack_name == NULL)
1021                 free(curr_pack);
1022         if (index_name == NULL)
1023                 free(curr_index);
1024
1025         return 0;
1026 }