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