Andrew's git / gitweb.git / builtin/unpack-objects.c
?
builtin / unpack-objects.con commit path: add repo_git_path and strbuf_repo_git_path (3181d86)
   1#include "builtin.h"
   2#include "cache.h"
   3#include "config.h"
   4#include "object.h"
   5#include "delta.h"
   6#include "pack.h"
   7#include "blob.h"
   8#include "commit.h"
   9#include "tag.h"
  10#include "tree.h"
  11#include "tree-walk.h"
  12#include "progress.h"
  13#include "decorate.h"
  14#include "fsck.h"
  15
  16static int dry_run, quiet, recover, has_errors, strict;
  17static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict]";
  18
  19/* We always read in 4kB chunks. */
  20static unsigned char buffer[4096];
  21static unsigned int offset, len;
  22static off_t consumed_bytes;
  23static off_t max_input_size;
  24static git_SHA_CTX ctx;
  25static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
  26
  27/*
  28 * When running under --strict mode, objects whose reachability are
  29 * suspect are kept in core without getting written in the object
  30 * store.
  31 */
  32struct obj_buffer {
  33        char *buffer;
  34        unsigned long size;
  35};
  36
  37static struct decoration obj_decorate;
  38
  39static struct obj_buffer *lookup_object_buffer(struct object *base)
  40{
  41        return lookup_decoration(&obj_decorate, base);
  42}
  43
  44static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
  45{
  46        struct obj_buffer *obj;
  47        obj = xcalloc(1, sizeof(struct obj_buffer));
  48        obj->buffer = buffer;
  49        obj->size = size;
  50        if (add_decoration(&obj_decorate, object, obj))
  51                die("object %s tried to add buffer twice!", oid_to_hex(&object->oid));
  52}
  53
  54/*
  55 * Make sure at least "min" bytes are available in the buffer, and
  56 * return the pointer to the buffer.
  57 */
  58static void *fill(int min)
  59{
  60        if (min <= len)
  61                return buffer + offset;
  62        if (min > sizeof(buffer))
  63                die("cannot fill %d bytes", min);
  64        if (offset) {
  65                git_SHA1_Update(&ctx, buffer, offset);
  66                memmove(buffer, buffer + offset, len);
  67                offset = 0;
  68        }
  69        do {
  70                ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
  71                if (ret <= 0) {
  72                        if (!ret)
  73                                die("early EOF");
  74                        die_errno("read error on input");
  75                }
  76                len += ret;
  77        } while (len < min);
  78        return buffer;
  79}
  80
  81static void use(int bytes)
  82{
  83        if (bytes > len)
  84                die("used more bytes than were available");
  85        len -= bytes;
  86        offset += bytes;
  87
  88        /* make sure off_t is sufficiently large not to wrap */
  89        if (signed_add_overflows(consumed_bytes, bytes))
  90                die("pack too large for current definition of off_t");
  91        consumed_bytes += bytes;
  92        if (max_input_size && consumed_bytes > max_input_size)
  93                die(_("pack exceeds maximum allowed size"));
  94}
  95
  96static void *get_data(unsigned long size)
  97{
  98        git_zstream stream;
  99        void *buf = xmallocz(size);
 100
 101        memset(&stream, 0, sizeof(stream));
 102
 103        stream.next_out = buf;
 104        stream.avail_out = size;
 105        stream.next_in = fill(1);
 106        stream.avail_in = len;
 107        git_inflate_init(&stream);
 108
 109        for (;;) {
 110                int ret = git_inflate(&stream, 0);
 111                use(len - stream.avail_in);
 112                if (stream.total_out == size && ret == Z_STREAM_END)
 113                        break;
 114                if (ret != Z_OK) {
 115                        error("inflate returned %d", ret);
 116                        free(buf);
 117                        buf = NULL;
 118                        if (!recover)
 119                                exit(1);
 120                        has_errors = 1;
 121                        break;
 122                }
 123                stream.next_in = fill(1);
 124                stream.avail_in = len;
 125        }
 126        git_inflate_end(&stream);
 127        return buf;
 128}
 129
 130struct delta_info {
 131        struct object_id base_oid;
 132        unsigned nr;
 133        off_t base_offset;
 134        unsigned long size;
 135        void *delta;
 136        struct delta_info *next;
 137};
 138
 139static struct delta_info *delta_list;
 140
 141static void add_delta_to_list(unsigned nr, const struct object_id *base_oid,
 142                              off_t base_offset,
 143                              void *delta, unsigned long size)
 144{
 145        struct delta_info *info = xmalloc(sizeof(*info));
 146
 147        oidcpy(&info->base_oid, base_oid);
 148        info->base_offset = base_offset;
 149        info->size = size;
 150        info->delta = delta;
 151        info->nr = nr;
 152        info->next = delta_list;
 153        delta_list = info;
 154}
 155
 156struct obj_info {
 157        off_t offset;
 158        struct object_id oid;
 159        struct object *obj;
 160};
 161
 162#define FLAG_OPEN (1u<<20)
 163#define FLAG_WRITTEN (1u<<21)
 164
 165static struct obj_info *obj_list;
 166static unsigned nr_objects;
 167
 168/*
 169 * Called only from check_object() after it verified this object
 170 * is Ok.
 171 */
 172static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
 173{
 174        struct object_id oid;
 175
 176        if (write_sha1_file(obj_buf->buffer, obj_buf->size, typename(obj->type), oid.hash) < 0)
 177                die("failed to write object %s", oid_to_hex(&obj->oid));
 178        obj->flags |= FLAG_WRITTEN;
 179}
 180
 181/*
 182 * At the very end of the processing, write_rest() scans the objects
 183 * that have reachability requirements and calls this function.
 184 * Verify its reachability and validity recursively and write it out.
 185 */
 186static int check_object(struct object *obj, int type, void *data, struct fsck_options *options)
 187{
 188        struct obj_buffer *obj_buf;
 189
 190        if (!obj)
 191                return 1;
 192
 193        if (obj->flags & FLAG_WRITTEN)
 194                return 0;
 195
 196        if (type != OBJ_ANY && obj->type != type)
 197                die("object type mismatch");
 198
 199        if (!(obj->flags & FLAG_OPEN)) {
 200                unsigned long size;
 201                int type = sha1_object_info(obj->oid.hash, &size);
 202                if (type != obj->type || type <= 0)
 203                        die("object of unexpected type");
 204                obj->flags |= FLAG_WRITTEN;
 205                return 0;
 206        }
 207
 208        obj_buf = lookup_object_buffer(obj);
 209        if (!obj_buf)
 210                die("Whoops! Cannot find object '%s'", oid_to_hex(&obj->oid));
 211        if (fsck_object(obj, obj_buf->buffer, obj_buf->size, &fsck_options))
 212                die("Error in object");
 213        fsck_options.walk = check_object;
 214        if (fsck_walk(obj, NULL, &fsck_options))
 215                die("Error on reachable objects of %s", oid_to_hex(&obj->oid));
 216        write_cached_object(obj, obj_buf);
 217        return 0;
 218}
 219
 220static void write_rest(void)
 221{
 222        unsigned i;
 223        for (i = 0; i < nr_objects; i++) {
 224                if (obj_list[i].obj)
 225                        check_object(obj_list[i].obj, OBJ_ANY, NULL, NULL);
 226        }
 227}
 228
 229static void added_object(unsigned nr, enum object_type type,
 230                         void *data, unsigned long size);
 231
 232/*
 233 * Write out nr-th object from the list, now we know the contents
 234 * of it.  Under --strict, this buffers structured objects in-core,
 235 * to be checked at the end.
 236 */
 237static void write_object(unsigned nr, enum object_type type,
 238                         void *buf, unsigned long size)
 239{
 240        if (!strict) {
 241                if (write_sha1_file(buf, size, typename(type), obj_list[nr].oid.hash) < 0)
 242                        die("failed to write object");
 243                added_object(nr, type, buf, size);
 244                free(buf);
 245                obj_list[nr].obj = NULL;
 246        } else if (type == OBJ_BLOB) {
 247                struct blob *blob;
 248                if (write_sha1_file(buf, size, typename(type), obj_list[nr].oid.hash) < 0)
 249                        die("failed to write object");
 250                added_object(nr, type, buf, size);
 251                free(buf);
 252
 253                blob = lookup_blob(&obj_list[nr].oid);
 254                if (blob)
 255                        blob->object.flags |= FLAG_WRITTEN;
 256                else
 257                        die("invalid blob object");
 258                obj_list[nr].obj = NULL;
 259        } else {
 260                struct object *obj;
 261                int eaten;
 262                hash_sha1_file(buf, size, typename(type), obj_list[nr].oid.hash);
 263                added_object(nr, type, buf, size);
 264                obj = parse_object_buffer(&obj_list[nr].oid, type, size, buf,
 265                                          &eaten);
 266                if (!obj)
 267                        die("invalid %s", typename(type));
 268                add_object_buffer(obj, buf, size);
 269                obj->flags |= FLAG_OPEN;
 270                obj_list[nr].obj = obj;
 271        }
 272}
 273
 274static void resolve_delta(unsigned nr, enum object_type type,
 275                          void *base, unsigned long base_size,
 276                          void *delta, unsigned long delta_size)
 277{
 278        void *result;
 279        unsigned long result_size;
 280
 281        result = patch_delta(base, base_size,
 282                             delta, delta_size,
 283                             &result_size);
 284        if (!result)
 285                die("failed to apply delta");
 286        free(delta);
 287        write_object(nr, type, result, result_size);
 288}
 289
 290/*
 291 * We now know the contents of an object (which is nr-th in the pack);
 292 * resolve all the deltified objects that are based on it.
 293 */
 294static void added_object(unsigned nr, enum object_type type,
 295                         void *data, unsigned long size)
 296{
 297        struct delta_info **p = &delta_list;
 298        struct delta_info *info;
 299
 300        while ((info = *p) != NULL) {
 301                if (!oidcmp(&info->base_oid, &obj_list[nr].oid) ||
 302                    info->base_offset == obj_list[nr].offset) {
 303                        *p = info->next;
 304                        p = &delta_list;
 305                        resolve_delta(info->nr, type, data, size,
 306                                      info->delta, info->size);
 307                        free(info);
 308                        continue;
 309                }
 310                p = &info->next;
 311        }
 312}
 313
 314static void unpack_non_delta_entry(enum object_type type, unsigned long size,
 315                                   unsigned nr)
 316{
 317        void *buf = get_data(size);
 318
 319        if (!dry_run && buf)
 320                write_object(nr, type, buf, size);
 321        else
 322                free(buf);
 323}
 324
 325static int resolve_against_held(unsigned nr, const struct object_id *base,
 326                                void *delta_data, unsigned long delta_size)
 327{
 328        struct object *obj;
 329        struct obj_buffer *obj_buffer;
 330        obj = lookup_object(base->hash);
 331        if (!obj)
 332                return 0;
 333        obj_buffer = lookup_object_buffer(obj);
 334        if (!obj_buffer)
 335                return 0;
 336        resolve_delta(nr, obj->type, obj_buffer->buffer,
 337                      obj_buffer->size, delta_data, delta_size);
 338        return 1;
 339}
 340
 341static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
 342                               unsigned nr)
 343{
 344        void *delta_data, *base;
 345        unsigned long base_size;
 346        struct object_id base_oid;
 347
 348        if (type == OBJ_REF_DELTA) {
 349                hashcpy(base_oid.hash, fill(GIT_SHA1_RAWSZ));
 350                use(GIT_SHA1_RAWSZ);
 351                delta_data = get_data(delta_size);
 352                if (dry_run || !delta_data) {
 353                        free(delta_data);
 354                        return;
 355                }
 356                if (has_object_file(&base_oid))
 357                        ; /* Ok we have this one */
 358                else if (resolve_against_held(nr, &base_oid,
 359                                              delta_data, delta_size))
 360                        return; /* we are done */
 361                else {
 362                        /* cannot resolve yet --- queue it */
 363                        oidclr(&obj_list[nr].oid);
 364                        add_delta_to_list(nr, &base_oid, 0, delta_data, delta_size);
 365                        return;
 366                }
 367        } else {
 368                unsigned base_found = 0;
 369                unsigned char *pack, c;
 370                off_t base_offset;
 371                unsigned lo, mid, hi;
 372
 373                pack = fill(1);
 374                c = *pack;
 375                use(1);
 376                base_offset = c & 127;
 377                while (c & 128) {
 378                        base_offset += 1;
 379                        if (!base_offset || MSB(base_offset, 7))
 380                                die("offset value overflow for delta base object");
 381                        pack = fill(1);
 382                        c = *pack;
 383                        use(1);
 384                        base_offset = (base_offset << 7) + (c & 127);
 385                }
 386                base_offset = obj_list[nr].offset - base_offset;
 387                if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
 388                        die("offset value out of bound for delta base object");
 389
 390                delta_data = get_data(delta_size);
 391                if (dry_run || !delta_data) {
 392                        free(delta_data);
 393                        return;
 394                }
 395                lo = 0;
 396                hi = nr;
 397                while (lo < hi) {
 398                        mid = (lo + hi)/2;
 399                        if (base_offset < obj_list[mid].offset) {
 400                                hi = mid;
 401                        } else if (base_offset > obj_list[mid].offset) {
 402                                lo = mid + 1;
 403                        } else {
 404                                oidcpy(&base_oid, &obj_list[mid].oid);
 405                                base_found = !is_null_oid(&base_oid);
 406                                break;
 407                        }
 408                }
 409                if (!base_found) {
 410                        /*
 411                         * The delta base object is itself a delta that
 412                         * has not been resolved yet.
 413                         */
 414                        oidclr(&obj_list[nr].oid);
 415                        add_delta_to_list(nr, &null_oid, base_offset, delta_data, delta_size);
 416                        return;
 417                }
 418        }
 419
 420        if (resolve_against_held(nr, &base_oid, delta_data, delta_size))
 421                return;
 422
 423        base = read_sha1_file(base_oid.hash, &type, &base_size);
 424        if (!base) {
 425                error("failed to read delta-pack base object %s",
 426                      oid_to_hex(&base_oid));
 427                if (!recover)
 428                        exit(1);
 429                has_errors = 1;
 430                return;
 431        }
 432        resolve_delta(nr, type, base, base_size, delta_data, delta_size);
 433        free(base);
 434}
 435
 436static void unpack_one(unsigned nr)
 437{
 438        unsigned shift;
 439        unsigned char *pack;
 440        unsigned long size, c;
 441        enum object_type type;
 442
 443        obj_list[nr].offset = consumed_bytes;
 444
 445        pack = fill(1);
 446        c = *pack;
 447        use(1);
 448        type = (c >> 4) & 7;
 449        size = (c & 15);
 450        shift = 4;
 451        while (c & 0x80) {
 452                pack = fill(1);
 453                c = *pack;
 454                use(1);
 455                size += (c & 0x7f) << shift;
 456                shift += 7;
 457        }
 458
 459        switch (type) {
 460        case OBJ_COMMIT:
 461        case OBJ_TREE:
 462        case OBJ_BLOB:
 463        case OBJ_TAG:
 464                unpack_non_delta_entry(type, size, nr);
 465                return;
 466        case OBJ_REF_DELTA:
 467        case OBJ_OFS_DELTA:
 468                unpack_delta_entry(type, size, nr);
 469                return;
 470        default:
 471                error("bad object type %d", type);
 472                has_errors = 1;
 473                if (recover)
 474                        return;
 475                exit(1);
 476        }
 477}
 478
 479static void unpack_all(void)
 480{
 481        int i;
 482        struct progress *progress = NULL;
 483        struct pack_header *hdr = fill(sizeof(struct pack_header));
 484
 485        nr_objects = ntohl(hdr->hdr_entries);
 486
 487        if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
 488                die("bad pack file");
 489        if (!pack_version_ok(hdr->hdr_version))
 490                die("unknown pack file version %"PRIu32,
 491                        ntohl(hdr->hdr_version));
 492        use(sizeof(struct pack_header));
 493
 494        if (!quiet)
 495                progress = start_progress(_("Unpacking objects"), nr_objects);
 496        obj_list = xcalloc(nr_objects, sizeof(*obj_list));
 497        for (i = 0; i < nr_objects; i++) {
 498                unpack_one(i);
 499                display_progress(progress, i + 1);
 500        }
 501        stop_progress(&progress);
 502
 503        if (delta_list)
 504                die("unresolved deltas left after unpacking");
 505}
 506
 507int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 508{
 509        int i;
 510        struct object_id oid;
 511
 512        check_replace_refs = 0;
 513
 514        git_config(git_default_config, NULL);
 515
 516        quiet = !isatty(2);
 517
 518        for (i = 1 ; i < argc; i++) {
 519                const char *arg = argv[i];
 520
 521                if (*arg == '-') {
 522                        if (!strcmp(arg, "-n")) {
 523                                dry_run = 1;
 524                                continue;
 525                        }
 526                        if (!strcmp(arg, "-q")) {
 527                                quiet = 1;
 528                                continue;
 529                        }
 530                        if (!strcmp(arg, "-r")) {
 531                                recover = 1;
 532                                continue;
 533                        }
 534                        if (!strcmp(arg, "--strict")) {
 535                                strict = 1;
 536                                continue;
 537                        }
 538                        if (skip_prefix(arg, "--strict=", &arg)) {
 539                                strict = 1;
 540                                fsck_set_msg_types(&fsck_options, arg);
 541                                continue;
 542                        }
 543                        if (starts_with(arg, "--pack_header=")) {
 544                                struct pack_header *hdr;
 545                                char *c;
 546
 547                                hdr = (struct pack_header *)buffer;
 548                                hdr->hdr_signature = htonl(PACK_SIGNATURE);
 549                                hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 550                                if (*c != ',')
 551                                        die("bad %s", arg);
 552                                hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 553                                if (*c)
 554                                        die("bad %s", arg);
 555                                len = sizeof(*hdr);
 556                                continue;
 557                        }
 558                        if (skip_prefix(arg, "--max-input-size=", &arg)) {
 559                                max_input_size = strtoumax(arg, NULL, 10);
 560                                continue;
 561                        }
 562                        usage(unpack_usage);
 563                }
 564
 565                /* We don't take any non-flag arguments now.. Maybe some day */
 566                usage(unpack_usage);
 567        }
 568        git_SHA1_Init(&ctx);
 569        unpack_all();
 570        git_SHA1_Update(&ctx, buffer, offset);
 571        git_SHA1_Final(oid.hash, &ctx);
 572        if (strict)
 573                write_rest();
 574        if (hashcmp(fill(GIT_SHA1_RAWSZ), oid.hash))
 575                die("final sha1 did not match");
 576        use(GIT_SHA1_RAWSZ);
 577
 578        /* Write the last part of the buffer to stdout */
 579        while (len) {
 580                int ret = xwrite(1, buffer + offset, len);
 581                if (ret <= 0)
 582                        break;
 583                len -= ret;
 584                offset += ret;
 585        }
 586
 587        /* All done */
 588        return has_errors;
 589}