builtin/unpack-objects.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "config.h"
   4 #include "object-store.h"
   5 #include "object.h"
   6 #include "delta.h"
   7 #include "pack.h"
   8 #include "blob.h"
   9 #include "commit.h"
  10 #include "tag.h"
  11 #include "tree.h"
  12 #include "tree-walk.h"
  13 #include "progress.h"
  14 #include "decorate.h"
  15 #include "fsck.h"
  16
  17 static int dry_run, quiet, recover, has_errors, strict;
  18 static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict]";
  19
  20 /* We always read in 4kB chunks. */
  21 static unsigned char buffer[4096];
  22 static unsigned int offset, len;
  23 static off_t consumed_bytes;
  24 static off_t max_input_size;
  25 static git_hash_ctx ctx;
  26 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
  27 static struct progress *progress;
  28
  29 /*
  30  * When running under --strict mode, objects whose reachability are
  31  * suspect are kept in core without getting written in the object
  32  * store.
  33  */
  34 struct obj_buffer {
  35         char *buffer;
  36         unsigned long size;
  37 };
  38
  39 static struct decoration obj_decorate;
  40
  41 static struct obj_buffer *lookup_object_buffer(struct object *base)
  42 {
  43         return lookup_decoration(&obj_decorate, base);
  44 }
  45
  46 static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
  47 {
  48         struct obj_buffer *obj;
  49         obj = xcalloc(1, sizeof(struct obj_buffer));
  50         obj->buffer = buffer;
  51         obj->size = size;
  52         if (add_decoration(&obj_decorate, object, obj))
  53                 die("object %s tried to add buffer twice!", oid_to_hex(&object->oid));
  54 }
  55
  56 /*
  57  * Make sure at least "min" bytes are available in the buffer, and
  58  * return the pointer to the buffer.
  59  */
  60 static void *fill(int min)
  61 {
  62         if (min <= len)
  63                 return buffer + offset;
  64         if (min > sizeof(buffer))
  65                 die("cannot fill %d bytes", min);
  66         if (offset) {
  67                 the_hash_algo->update_fn(&ctx, buffer, offset);
  68                 memmove(buffer, buffer + offset, len);
  69                 offset = 0;
  70         }
  71         do {
  72                 ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
  73                 if (ret <= 0) {
  74                         if (!ret)
  75                                 die("early EOF");
  76                         die_errno("read error on input");
  77                 }
  78                 len += ret;
  79         } while (len < min);
  80         return buffer;
  81 }
  82
  83 static void use(int bytes)
  84 {
  85         if (bytes > len)
  86                 die("used more bytes than were available");
  87         len -= bytes;
  88         offset += bytes;
  89
  90         /* make sure off_t is sufficiently large not to wrap */
  91         if (signed_add_overflows(consumed_bytes, bytes))
  92                 die("pack too large for current definition of off_t");
  93         consumed_bytes += bytes;
  94         if (max_input_size && consumed_bytes > max_input_size)
  95                 die(_("pack exceeds maximum allowed size"));
  96         display_throughput(progress, consumed_bytes);
  97 }
  98
  99 static void *get_data(unsigned long size)
 100 {
 101         git_zstream stream;
 102         void *buf = xmallocz(size);
 103
 104         memset(&stream, 0, sizeof(stream));
 105
 106         stream.next_out = buf;
 107         stream.avail_out = size;
 108         stream.next_in = fill(1);
 109         stream.avail_in = len;
 110         git_inflate_init(&stream);
 111
 112         for (;;) {
 113                 int ret = git_inflate(&stream, 0);
 114                 use(len - stream.avail_in);
 115                 if (stream.total_out == size && ret == Z_STREAM_END)
 116                         break;
 117                 if (ret != Z_OK) {
 118                         error("inflate returned %d", ret);
 119                         FREE_AND_NULL(buf);
 120                         if (!recover)
 121                                 exit(1);
 122                         has_errors = 1;
 123                         break;
 124                 }
 125                 stream.next_in = fill(1);
 126                 stream.avail_in = len;
 127         }
 128         git_inflate_end(&stream);
 129         return buf;
 130 }
 131
 132 struct delta_info {
 133         struct object_id base_oid;
 134         unsigned nr;
 135         off_t base_offset;
 136         unsigned long size;
 137         void *delta;
 138         struct delta_info *next;
 139 };
 140
 141 static struct delta_info *delta_list;
 142
 143 static void add_delta_to_list(unsigned nr, const struct object_id *base_oid,
 144                               off_t base_offset,
 145                               void *delta, unsigned long size)
 146 {
 147         struct delta_info *info = xmalloc(sizeof(*info));
 148
 149         oidcpy(&info->base_oid, base_oid);
 150         info->base_offset = base_offset;
 151         info->size = size;
 152         info->delta = delta;
 153         info->nr = nr;
 154         info->next = delta_list;
 155         delta_list = info;
 156 }
 157
 158 struct obj_info {
 159         off_t offset;
 160         struct object_id oid;
 161         struct object *obj;
 162 };
 163
 164 /* Remember to update object flag allocation in object.h */
 165 #define FLAG_OPEN (1u<<20)
 166 #define FLAG_WRITTEN (1u<<21)
 167
 168 static struct obj_info *obj_list;
 169 static unsigned nr_objects;
 170
 171 /*
 172  * Called only from check_object() after it verified this object
 173  * is Ok.
 174  */
 175 static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
 176 {
 177         struct object_id oid;
 178
 179         if (write_object_file(obj_buf->buffer, obj_buf->size,
 180                               type_name(obj->type), &oid) < 0)
 181                 die("failed to write object %s", oid_to_hex(&obj->oid));
 182         obj->flags |= FLAG_WRITTEN;
 183 }
 184
 185 /*
 186  * At the very end of the processing, write_rest() scans the objects
 187  * that have reachability requirements and calls this function.
 188  * Verify its reachability and validity recursively and write it out.
 189  */
 190 static int check_object(struct object *obj, int type, void *data, struct fsck_options *options)
 191 {
 192         struct obj_buffer *obj_buf;
 193
 194         if (!obj)
 195                 return 1;
 196
 197         if (obj->flags & FLAG_WRITTEN)
 198                 return 0;
 199
 200         if (type != OBJ_ANY && obj->type != type)
 201                 die("object type mismatch");
 202
 203         if (!(obj->flags & FLAG_OPEN)) {
 204                 unsigned long size;
 205                 int type = oid_object_info(the_repository, &obj->oid, &size);
 206                 if (type != obj->type || type <= 0)
 207                         die("object of unexpected type");
 208                 obj->flags |= FLAG_WRITTEN;
 209                 return 0;
 210         }
 211
 212         obj_buf = lookup_object_buffer(obj);
 213         if (!obj_buf)
 214                 die("Whoops! Cannot find object '%s'", oid_to_hex(&obj->oid));
 215         if (fsck_object(obj, obj_buf->buffer, obj_buf->size, &fsck_options))
 216                 die("fsck error in packed object");
 217         fsck_options.walk = check_object;
 218         if (fsck_walk(obj, NULL, &fsck_options))
 219                 die("Error on reachable objects of %s", oid_to_hex(&obj->oid));
 220         write_cached_object(obj, obj_buf);
 221         return 0;
 222 }
 223
 224 static void write_rest(void)
 225 {
 226         unsigned i;
 227         for (i = 0; i < nr_objects; i++) {
 228                 if (obj_list[i].obj)
 229                         check_object(obj_list[i].obj, OBJ_ANY, NULL, NULL);
 230         }
 231 }
 232
 233 static void added_object(unsigned nr, enum object_type type,
 234                          void *data, unsigned long size);
 235
 236 /*
 237  * Write out nr-th object from the list, now we know the contents
 238  * of it.  Under --strict, this buffers structured objects in-core,
 239  * to be checked at the end.
 240  */
 241 static void write_object(unsigned nr, enum object_type type,
 242                          void *buf, unsigned long size)
 243 {
 244         if (!strict) {
 245                 if (write_object_file(buf, size, type_name(type),
 246                                       &obj_list[nr].oid) < 0)
 247                         die("failed to write object");
 248                 added_object(nr, type, buf, size);
 249                 free(buf);
 250                 obj_list[nr].obj = NULL;
 251         } else if (type == OBJ_BLOB) {
 252                 struct blob *blob;
 253                 if (write_object_file(buf, size, type_name(type),
 254                                       &obj_list[nr].oid) < 0)
 255                         die("failed to write object");
 256                 added_object(nr, type, buf, size);
 257                 free(buf);
 258
 259                 blob = lookup_blob(the_repository, &obj_list[nr].oid);
 260                 if (blob)
 261                         blob->object.flags |= FLAG_WRITTEN;
 262                 else
 263                         die("invalid blob object");
 264                 obj_list[nr].obj = NULL;
 265         } else {
 266                 struct object *obj;
 267                 int eaten;
 268                 hash_object_file(the_hash_algo, buf, size, type_name(type),
 269                                  &obj_list[nr].oid);
 270                 added_object(nr, type, buf, size);
 271                 obj = parse_object_buffer(the_repository, &obj_list[nr].oid,
 272                                           type, size, buf,
 273                                           &eaten);
 274                 if (!obj)
 275                         die("invalid %s", type_name(type));
 276                 add_object_buffer(obj, buf, size);
 277                 obj->flags |= FLAG_OPEN;
 278                 obj_list[nr].obj = obj;
 279         }
 280 }
 281
 282 static void resolve_delta(unsigned nr, enum object_type type,
 283                           void *base, unsigned long base_size,
 284                           void *delta, unsigned long delta_size)
 285 {
 286         void *result;
 287         unsigned long result_size;
 288
 289         result = patch_delta(base, base_size,
 290                              delta, delta_size,
 291                              &result_size);
 292         if (!result)
 293                 die("failed to apply delta");
 294         free(delta);
 295         write_object(nr, type, result, result_size);
 296 }
 297
 298 /*
 299  * We now know the contents of an object (which is nr-th in the pack);
 300  * resolve all the deltified objects that are based on it.
 301  */
 302 static void added_object(unsigned nr, enum object_type type,
 303                          void *data, unsigned long size)
 304 {
 305         struct delta_info **p = &delta_list;
 306         struct delta_info *info;
 307
 308         while ((info = *p) != NULL) {
 309                 if (oideq(&info->base_oid, &obj_list[nr].oid) ||
 310                     info->base_offset == obj_list[nr].offset) {
 311                         *p = info->next;
 312                         p = &delta_list;
 313                         resolve_delta(info->nr, type, data, size,
 314                                       info->delta, info->size);
 315                         free(info);
 316                         continue;
 317                 }
 318                 p = &info->next;
 319         }
 320 }
 321
 322 static void unpack_non_delta_entry(enum object_type type, unsigned long size,
 323                                    unsigned nr)
 324 {
 325         void *buf = get_data(size);
 326
 327         if (!dry_run && buf)
 328                 write_object(nr, type, buf, size);
 329         else
 330                 free(buf);
 331 }
 332
 333 static int resolve_against_held(unsigned nr, const struct object_id *base,
 334                                 void *delta_data, unsigned long delta_size)
 335 {
 336         struct object *obj;
 337         struct obj_buffer *obj_buffer;
 338         obj = lookup_object(the_repository, base);
 339         if (!obj)
 340                 return 0;
 341         obj_buffer = lookup_object_buffer(obj);
 342         if (!obj_buffer)
 343                 return 0;
 344         resolve_delta(nr, obj->type, obj_buffer->buffer,
 345                       obj_buffer->size, delta_data, delta_size);
 346         return 1;
 347 }
 348
 349 static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
 350                                unsigned nr)
 351 {
 352         void *delta_data, *base;
 353         unsigned long base_size;
 354         struct object_id base_oid;
 355
 356         if (type == OBJ_REF_DELTA) {
 357                 hashcpy(base_oid.hash, fill(the_hash_algo->rawsz));
 358                 use(the_hash_algo->rawsz);
 359                 delta_data = get_data(delta_size);
 360                 if (dry_run || !delta_data) {
 361                         free(delta_data);
 362                         return;
 363                 }
 364                 if (has_object_file(&base_oid))
 365                         ; /* Ok we have this one */
 366                 else if (resolve_against_held(nr, &base_oid,
 367                                               delta_data, delta_size))
 368                         return; /* we are done */
 369                 else {
 370                         /* cannot resolve yet --- queue it */
 371                         oidclr(&obj_list[nr].oid);
 372                         add_delta_to_list(nr, &base_oid, 0, delta_data, delta_size);
 373                         return;
 374                 }
 375         } else {
 376                 unsigned base_found = 0;
 377                 unsigned char *pack, c;
 378                 off_t base_offset;
 379                 unsigned lo, mid, hi;
 380
 381                 pack = fill(1);
 382                 c = *pack;
 383                 use(1);
 384                 base_offset = c & 127;
 385                 while (c & 128) {
 386                         base_offset += 1;
 387                         if (!base_offset || MSB(base_offset, 7))
 388                                 die("offset value overflow for delta base object");
 389                         pack = fill(1);
 390                         c = *pack;
 391                         use(1);
 392                         base_offset = (base_offset << 7) + (c & 127);
 393                 }
 394                 base_offset = obj_list[nr].offset - base_offset;
 395                 if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
 396                         die("offset value out of bound for delta base object");
 397
 398                 delta_data = get_data(delta_size);
 399                 if (dry_run || !delta_data) {
 400                         free(delta_data);
 401                         return;
 402                 }
 403                 lo = 0;
 404                 hi = nr;
 405                 while (lo < hi) {
 406                         mid = lo + (hi - lo) / 2;
 407                         if (base_offset < obj_list[mid].offset) {
 408                                 hi = mid;
 409                         } else if (base_offset > obj_list[mid].offset) {
 410                                 lo = mid + 1;
 411                         } else {
 412                                 oidcpy(&base_oid, &obj_list[mid].oid);
 413                                 base_found = !is_null_oid(&base_oid);
 414                                 break;
 415                         }
 416                 }
 417                 if (!base_found) {
 418                         /*
 419                          * The delta base object is itself a delta that
 420                          * has not been resolved yet.
 421                          */
 422                         oidclr(&obj_list[nr].oid);
 423                         add_delta_to_list(nr, &null_oid, base_offset, delta_data, delta_size);
 424                         return;
 425                 }
 426         }
 427
 428         if (resolve_against_held(nr, &base_oid, delta_data, delta_size))
 429                 return;
 430
 431         base = read_object_file(&base_oid, &type, &base_size);
 432         if (!base) {
 433                 error("failed to read delta-pack base object %s",
 434                       oid_to_hex(&base_oid));
 435                 if (!recover)
 436                         exit(1);
 437                 has_errors = 1;
 438                 return;
 439         }
 440         resolve_delta(nr, type, base, base_size, delta_data, delta_size);
 441         free(base);
 442 }
 443
 444 static void unpack_one(unsigned nr)
 445 {
 446         unsigned shift;
 447         unsigned char *pack;
 448         unsigned long size, c;
 449         enum object_type type;
 450
 451         obj_list[nr].offset = consumed_bytes;
 452
 453         pack = fill(1);
 454         c = *pack;
 455         use(1);
 456         type = (c >> 4) & 7;
 457         size = (c & 15);
 458         shift = 4;
 459         while (c & 0x80) {
 460                 pack = fill(1);
 461                 c = *pack;
 462                 use(1);
 463                 size += (c & 0x7f) << shift;
 464                 shift += 7;
 465         }
 466
 467         switch (type) {
 468         case OBJ_COMMIT:
 469         case OBJ_TREE:
 470         case OBJ_BLOB:
 471         case OBJ_TAG:
 472                 unpack_non_delta_entry(type, size, nr);
 473                 return;
 474         case OBJ_REF_DELTA:
 475         case OBJ_OFS_DELTA:
 476                 unpack_delta_entry(type, size, nr);
 477                 return;
 478         default:
 479                 error("bad object type %d", type);
 480                 has_errors = 1;
 481                 if (recover)
 482                         return;
 483                 exit(1);
 484         }
 485 }
 486
 487 static void unpack_all(void)
 488 {
 489         int i;
 490         struct pack_header *hdr = fill(sizeof(struct pack_header));
 491
 492         nr_objects = ntohl(hdr->hdr_entries);
 493
 494         if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
 495                 die("bad pack file");
 496         if (!pack_version_ok(hdr->hdr_version))
 497                 die("unknown pack file version %"PRIu32,
 498                         ntohl(hdr->hdr_version));
 499         use(sizeof(struct pack_header));
 500
 501         if (!quiet)
 502                 progress = start_progress(_("Unpacking objects"), nr_objects);
 503         obj_list = xcalloc(nr_objects, sizeof(*obj_list));
 504         for (i = 0; i < nr_objects; i++) {
 505                 unpack_one(i);
 506                 display_progress(progress, i + 1);
 507         }
 508         stop_progress(&progress);
 509
 510         if (delta_list)
 511                 die("unresolved deltas left after unpacking");
 512 }
 513
 514 int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 515 {
 516         int i;
 517         struct object_id oid;
 518
 519         read_replace_refs = 0;
 520
 521         git_config(git_default_config, NULL);
 522
 523         quiet = !isatty(2);
 524
 525         for (i = 1 ; i < argc; i++) {
 526                 const char *arg = argv[i];
 527
 528                 if (*arg == '-') {
 529                         if (!strcmp(arg, "-n")) {
 530                                 dry_run = 1;
 531                                 continue;
 532                         }
 533                         if (!strcmp(arg, "-q")) {
 534                                 quiet = 1;
 535                                 continue;
 536                         }
 537                         if (!strcmp(arg, "-r")) {
 538                                 recover = 1;
 539                                 continue;
 540                         }
 541                         if (!strcmp(arg, "--strict")) {
 542                                 strict = 1;
 543                                 continue;
 544                         }
 545                         if (skip_prefix(arg, "--strict=", &arg)) {
 546                                 strict = 1;
 547                                 fsck_set_msg_types(&fsck_options, arg);
 548                                 continue;
 549                         }
 550                         if (starts_with(arg, "--pack_header=")) {
 551                                 struct pack_header *hdr;
 552                                 char *c;
 553
 554                                 hdr = (struct pack_header *)buffer;
 555                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
 556                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 557                                 if (*c != ',')
 558                                         die("bad %s", arg);
 559                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 560                                 if (*c)
 561                                         die("bad %s", arg);
 562                                 len = sizeof(*hdr);
 563                                 continue;
 564                         }
 565                         if (skip_prefix(arg, "--max-input-size=", &arg)) {
 566                                 max_input_size = strtoumax(arg, NULL, 10);
 567                                 continue;
 568                         }
 569                         usage(unpack_usage);
 570                 }
 571
 572                 /* We don't take any non-flag arguments now.. Maybe some day */
 573                 usage(unpack_usage);
 574         }
 575         the_hash_algo->init_fn(&ctx);
 576         unpack_all();
 577         the_hash_algo->update_fn(&ctx, buffer, offset);
 578         the_hash_algo->final_fn(oid.hash, &ctx);
 579         if (strict) {
 580                 write_rest();
 581                 if (fsck_finish(&fsck_options))
 582                         die(_("fsck error in pack objects"));
 583         }
 584         if (!hasheq(fill(the_hash_algo->rawsz), oid.hash))
 585                 die("final sha1 did not match");
 586         use(the_hash_algo->rawsz);
 587
 588         /* Write the last part of the buffer to stdout */
 589         while (len) {
 590                 int ret = xwrite(1, buffer + offset, len);
 591                 if (ret <= 0)
 592                         break;
 593                 len -= ret;
 594                 offset += ret;
 595         }
 596
 597         /* All done */
 598         return has_errors;
 599 }