4532aa083154ae7e9be07014d3761821fa6c4ddc
[git/git.git] / builtin / unpack-objects.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "object.h"
4 #include "delta.h"
5 #include "pack.h"
6 #include "blob.h"
7 #include "commit.h"
8 #include "tag.h"
9 #include "tree.h"
10 #include "tree-walk.h"
11 #include "progress.h"
12 #include "decorate.h"
13 #include "fsck.h"
14
15 static int dry_run, quiet, recover, has_errors, strict;
16 static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict]";
17
18 /* We always read in 4kB chunks. */
19 static unsigned char buffer[4096];
20 static unsigned int offset, len;
21 static off_t consumed_bytes;
22 static off_t max_input_size;
23 static git_SHA_CTX ctx;
24 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
25
26 /*
27 * When running under --strict mode, objects whose reachability are
28 * suspect are kept in core without getting written in the object
29 * store.
30 */
31 struct obj_buffer {
32 char *buffer;
33 unsigned long size;
34 };
35
36 static struct decoration obj_decorate;
37
38 static struct obj_buffer *lookup_object_buffer(struct object *base)
39 {
40 return lookup_decoration(&obj_decorate, base);
41 }
42
43 static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
44 {
45 struct obj_buffer *obj;
46 obj = xcalloc(1, sizeof(struct obj_buffer));
47 obj->buffer = buffer;
48 obj->size = size;
49 if (add_decoration(&obj_decorate, object, obj))
50 die("object %s tried to add buffer twice!", oid_to_hex(&object->oid));
51 }
52
53 /*
54 * Make sure at least "min" bytes are available in the buffer, and
55 * return the pointer to the buffer.
56 */
57 static void *fill(int min)
58 {
59 if (min <= len)
60 return buffer + offset;
61 if (min > sizeof(buffer))
62 die("cannot fill %d bytes", min);
63 if (offset) {
64 git_SHA1_Update(&ctx, buffer, offset);
65 memmove(buffer, buffer + offset, len);
66 offset = 0;
67 }
68 do {
69 ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
70 if (ret <= 0) {
71 if (!ret)
72 die("early EOF");
73 die_errno("read error on input");
74 }
75 len += ret;
76 } while (len < min);
77 return buffer;
78 }
79
80 static void use(int bytes)
81 {
82 if (bytes > len)
83 die("used more bytes than were available");
84 len -= bytes;
85 offset += bytes;
86
87 /* make sure off_t is sufficiently large not to wrap */
88 if (signed_add_overflows(consumed_bytes, bytes))
89 die("pack too large for current definition of off_t");
90 consumed_bytes += bytes;
91 if (max_input_size && consumed_bytes > max_input_size)
92 die(_("pack exceeds maximum allowed size"));
93 }
94
95 static void *get_data(unsigned long size)
96 {
97 git_zstream stream;
98 void *buf = xmallocz(size);
99
100 memset(&stream, 0, sizeof(stream));
101
102 stream.next_out = buf;
103 stream.avail_out = size;
104 stream.next_in = fill(1);
105 stream.avail_in = len;
106 git_inflate_init(&stream);
107
108 for (;;) {
109 int ret = git_inflate(&stream, 0);
110 use(len - stream.avail_in);
111 if (stream.total_out == size && ret == Z_STREAM_END)
112 break;
113 if (ret != Z_OK) {
114 error("inflate returned %d", ret);
115 free(buf);
116 buf = NULL;
117 if (!recover)
118 exit(1);
119 has_errors = 1;
120 break;
121 }
122 stream.next_in = fill(1);
123 stream.avail_in = len;
124 }
125 git_inflate_end(&stream);
126 return buf;
127 }
128
129 struct delta_info {
130 unsigned char base_sha1[20];
131 unsigned nr;
132 off_t base_offset;
133 unsigned long size;
134 void *delta;
135 struct delta_info *next;
136 };
137
138 static struct delta_info *delta_list;
139
140 static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1,
141 off_t base_offset,
142 void *delta, unsigned long size)
143 {
144 struct delta_info *info = xmalloc(sizeof(*info));
145
146 hashcpy(info->base_sha1, base_sha1);
147 info->base_offset = base_offset;
148 info->size = size;
149 info->delta = delta;
150 info->nr = nr;
151 info->next = delta_list;
152 delta_list = info;
153 }
154
155 struct obj_info {
156 off_t offset;
157 unsigned char sha1[20];
158 struct object *obj;
159 };
160
161 #define FLAG_OPEN (1u<<20)
162 #define FLAG_WRITTEN (1u<<21)
163
164 static struct obj_info *obj_list;
165 static unsigned nr_objects;
166
167 /*
168 * Called only from check_object() after it verified this object
169 * is Ok.
170 */
171 static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
172 {
173 unsigned char sha1[20];
174
175 if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type), sha1) < 0)
176 die("failed to write object %s", oid_to_hex(&obj->oid));
177 obj->flags |= FLAG_WRITTEN;
178 }
179
180 /*
181 * At the very end of the processing, write_rest() scans the objects
182 * that have reachability requirements and calls this function.
183 * Verify its reachability and validity recursively and write it out.
184 */
185 static int check_object(struct object *obj, int type, void *data, struct fsck_options *options)
186 {
187 struct obj_buffer *obj_buf;
188
189 if (!obj)
190 return 1;
191
192 if (obj->flags & FLAG_WRITTEN)
193 return 0;
194
195 if (type != OBJ_ANY && obj->type != type)
196 die("object type mismatch");
197
198 if (!(obj->flags & FLAG_OPEN)) {
199 unsigned long size;
200 int type = sha1_object_info(obj->oid.hash, &size);
201 if (type != obj->type || type <= 0)
202 die("object of unexpected type");
203 obj->flags |= FLAG_WRITTEN;
204 return 0;
205 }
206
207 obj_buf = lookup_object_buffer(obj);
208 if (!obj_buf)
209 die("Whoops! Cannot find object '%s'", oid_to_hex(&obj->oid));
210 if (fsck_object(obj, obj_buf->buffer, obj_buf->size, &fsck_options))
211 die("Error in object");
212 fsck_options.walk = check_object;
213 if (fsck_walk(obj, NULL, &fsck_options))
214 die("Error on reachable objects of %s", oid_to_hex(&obj->oid));
215 write_cached_object(obj, obj_buf);
216 return 0;
217 }
218
219 static void write_rest(void)
220 {
221 unsigned i;
222 for (i = 0; i < nr_objects; i++) {
223 if (obj_list[i].obj)
224 check_object(obj_list[i].obj, OBJ_ANY, NULL, NULL);
225 }
226 }
227
228 static void added_object(unsigned nr, enum object_type type,
229 void *data, unsigned long size);
230
231 /*
232 * Write out nr-th object from the list, now we know the contents
233 * of it. Under --strict, this buffers structured objects in-core,
234 * to be checked at the end.
235 */
236 static void write_object(unsigned nr, enum object_type type,
237 void *buf, unsigned long size)
238 {
239 if (!strict) {
240 if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
241 die("failed to write object");
242 added_object(nr, type, buf, size);
243 free(buf);
244 obj_list[nr].obj = NULL;
245 } else if (type == OBJ_BLOB) {
246 struct blob *blob;
247 if (write_sha1_file(buf, size, typename(type), obj_list[nr].sha1) < 0)
248 die("failed to write object");
249 added_object(nr, type, buf, size);
250 free(buf);
251
252 blob = lookup_blob(obj_list[nr].sha1);
253 if (blob)
254 blob->object.flags |= FLAG_WRITTEN;
255 else
256 die("invalid blob object");
257 obj_list[nr].obj = NULL;
258 } else {
259 struct object *obj;
260 int eaten;
261 hash_sha1_file(buf, size, typename(type), obj_list[nr].sha1);
262 added_object(nr, type, buf, size);
263 obj = parse_object_buffer(obj_list[nr].sha1, type, size, buf, &eaten);
264 if (!obj)
265 die("invalid %s", typename(type));
266 add_object_buffer(obj, buf, size);
267 obj->flags |= FLAG_OPEN;
268 obj_list[nr].obj = obj;
269 }
270 }
271
272 static void resolve_delta(unsigned nr, enum object_type type,
273 void *base, unsigned long base_size,
274 void *delta, unsigned long delta_size)
275 {
276 void *result;
277 unsigned long result_size;
278
279 result = patch_delta(base, base_size,
280 delta, delta_size,
281 &result_size);
282 if (!result)
283 die("failed to apply delta");
284 free(delta);
285 write_object(nr, type, result, result_size);
286 }
287
288 /*
289 * We now know the contents of an object (which is nr-th in the pack);
290 * resolve all the deltified objects that are based on it.
291 */
292 static void added_object(unsigned nr, enum object_type type,
293 void *data, unsigned long size)
294 {
295 struct delta_info **p = &delta_list;
296 struct delta_info *info;
297
298 while ((info = *p) != NULL) {
299 if (!hashcmp(info->base_sha1, obj_list[nr].sha1) ||
300 info->base_offset == obj_list[nr].offset) {
301 *p = info->next;
302 p = &delta_list;
303 resolve_delta(info->nr, type, data, size,
304 info->delta, info->size);
305 free(info);
306 continue;
307 }
308 p = &info->next;
309 }
310 }
311
312 static void unpack_non_delta_entry(enum object_type type, unsigned long size,
313 unsigned nr)
314 {
315 void *buf = get_data(size);
316
317 if (!dry_run && buf)
318 write_object(nr, type, buf, size);
319 else
320 free(buf);
321 }
322
323 static int resolve_against_held(unsigned nr, const unsigned char *base,
324 void *delta_data, unsigned long delta_size)
325 {
326 struct object *obj;
327 struct obj_buffer *obj_buffer;
328 obj = lookup_object(base);
329 if (!obj)
330 return 0;
331 obj_buffer = lookup_object_buffer(obj);
332 if (!obj_buffer)
333 return 0;
334 resolve_delta(nr, obj->type, obj_buffer->buffer,
335 obj_buffer->size, delta_data, delta_size);
336 return 1;
337 }
338
339 static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
340 unsigned nr)
341 {
342 void *delta_data, *base;
343 unsigned long base_size;
344 unsigned char base_sha1[20];
345
346 if (type == OBJ_REF_DELTA) {
347 hashcpy(base_sha1, fill(20));
348 use(20);
349 delta_data = get_data(delta_size);
350 if (dry_run || !delta_data) {
351 free(delta_data);
352 return;
353 }
354 if (has_sha1_file(base_sha1))
355 ; /* Ok we have this one */
356 else if (resolve_against_held(nr, base_sha1,
357 delta_data, delta_size))
358 return; /* we are done */
359 else {
360 /* cannot resolve yet --- queue it */
361 hashclr(obj_list[nr].sha1);
362 add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size);
363 return;
364 }
365 } else {
366 unsigned base_found = 0;
367 unsigned char *pack, c;
368 off_t base_offset;
369 unsigned lo, mid, hi;
370
371 pack = fill(1);
372 c = *pack;
373 use(1);
374 base_offset = c & 127;
375 while (c & 128) {
376 base_offset += 1;
377 if (!base_offset || MSB(base_offset, 7))
378 die("offset value overflow for delta base object");
379 pack = fill(1);
380 c = *pack;
381 use(1);
382 base_offset = (base_offset << 7) + (c & 127);
383 }
384 base_offset = obj_list[nr].offset - base_offset;
385 if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
386 die("offset value out of bound for delta base object");
387
388 delta_data = get_data(delta_size);
389 if (dry_run || !delta_data) {
390 free(delta_data);
391 return;
392 }
393 lo = 0;
394 hi = nr;
395 while (lo < hi) {
396 mid = (lo + hi)/2;
397 if (base_offset < obj_list[mid].offset) {
398 hi = mid;
399 } else if (base_offset > obj_list[mid].offset) {
400 lo = mid + 1;
401 } else {
402 hashcpy(base_sha1, obj_list[mid].sha1);
403 base_found = !is_null_sha1(base_sha1);
404 break;
405 }
406 }
407 if (!base_found) {
408 /*
409 * The delta base object is itself a delta that
410 * has not been resolved yet.
411 */
412 hashclr(obj_list[nr].sha1);
413 add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size);
414 return;
415 }
416 }
417
418 if (resolve_against_held(nr, base_sha1, delta_data, delta_size))
419 return;
420
421 base = read_sha1_file(base_sha1, &type, &base_size);
422 if (!base) {
423 error("failed to read delta-pack base object %s",
424 sha1_to_hex(base_sha1));
425 if (!recover)
426 exit(1);
427 has_errors = 1;
428 return;
429 }
430 resolve_delta(nr, type, base, base_size, delta_data, delta_size);
431 free(base);
432 }
433
434 static void unpack_one(unsigned nr)
435 {
436 unsigned shift;
437 unsigned char *pack;
438 unsigned long size, c;
439 enum object_type type;
440
441 obj_list[nr].offset = consumed_bytes;
442
443 pack = fill(1);
444 c = *pack;
445 use(1);
446 type = (c >> 4) & 7;
447 size = (c & 15);
448 shift = 4;
449 while (c & 0x80) {
450 pack = fill(1);
451 c = *pack;
452 use(1);
453 size += (c & 0x7f) << shift;
454 shift += 7;
455 }
456
457 switch (type) {
458 case OBJ_COMMIT:
459 case OBJ_TREE:
460 case OBJ_BLOB:
461 case OBJ_TAG:
462 unpack_non_delta_entry(type, size, nr);
463 return;
464 case OBJ_REF_DELTA:
465 case OBJ_OFS_DELTA:
466 unpack_delta_entry(type, size, nr);
467 return;
468 default:
469 error("bad object type %d", type);
470 has_errors = 1;
471 if (recover)
472 return;
473 exit(1);
474 }
475 }
476
477 static void unpack_all(void)
478 {
479 int i;
480 struct progress *progress = NULL;
481 struct pack_header *hdr = fill(sizeof(struct pack_header));
482
483 nr_objects = ntohl(hdr->hdr_entries);
484
485 if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
486 die("bad pack file");
487 if (!pack_version_ok(hdr->hdr_version))
488 die("unknown pack file version %"PRIu32,
489 ntohl(hdr->hdr_version));
490 use(sizeof(struct pack_header));
491
492 if (!quiet)
493 progress = start_progress(_("Unpacking objects"), nr_objects);
494 obj_list = xcalloc(nr_objects, sizeof(*obj_list));
495 for (i = 0; i < nr_objects; i++) {
496 unpack_one(i);
497 display_progress(progress, i + 1);
498 }
499 stop_progress(&progress);
500
501 if (delta_list)
502 die("unresolved deltas left after unpacking");
503 }
504
505 int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
506 {
507 int i;
508 unsigned char sha1[20];
509
510 check_replace_refs = 0;
511
512 git_config(git_default_config, NULL);
513
514 quiet = !isatty(2);
515
516 for (i = 1 ; i < argc; i++) {
517 const char *arg = argv[i];
518
519 if (*arg == '-') {
520 if (!strcmp(arg, "-n")) {
521 dry_run = 1;
522 continue;
523 }
524 if (!strcmp(arg, "-q")) {
525 quiet = 1;
526 continue;
527 }
528 if (!strcmp(arg, "-r")) {
529 recover = 1;
530 continue;
531 }
532 if (!strcmp(arg, "--strict")) {
533 strict = 1;
534 continue;
535 }
536 if (skip_prefix(arg, "--strict=", &arg)) {
537 strict = 1;
538 fsck_set_msg_types(&fsck_options, arg);
539 continue;
540 }
541 if (starts_with(arg, "--pack_header=")) {
542 struct pack_header *hdr;
543 char *c;
544
545 hdr = (struct pack_header *)buffer;
546 hdr->hdr_signature = htonl(PACK_SIGNATURE);
547 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
548 if (*c != ',')
549 die("bad %s", arg);
550 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
551 if (*c)
552 die("bad %s", arg);
553 len = sizeof(*hdr);
554 continue;
555 }
556 if (skip_prefix(arg, "--max-input-size=", &arg)) {
557 max_input_size = strtoumax(arg, NULL, 10);
558 continue;
559 }
560 usage(unpack_usage);
561 }
562
563 /* We don't take any non-flag arguments now.. Maybe some day */
564 usage(unpack_usage);
565 }
566 git_SHA1_Init(&ctx);
567 unpack_all();
568 git_SHA1_Update(&ctx, buffer, offset);
569 git_SHA1_Final(sha1, &ctx);
570 if (strict)
571 write_rest();
572 if (hashcmp(fill(20), sha1))
573 die("final sha1 did not match");
574 use(20);
575
576 /* Write the last part of the buffer to stdout */
577 while (len) {
578 int ret = xwrite(1, buffer + offset, len);
579 if (ret <= 0)
580 break;
581 len -= ret;
582 offset += ret;
583 }
584
585 /* All done */
586 return has_errors;
587 }