sha1_file.con commit Merge branch 'jk/config-with-empty-section' (66bea73)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 *
   6 * This handles basic git sha1 object files - packing, unpacking,
   7 * creation etc.
   8 */
   9#include "cache.h"
  10#include "string-list.h"
  11#include "delta.h"
  12#include "pack.h"
  13#include "blob.h"
  14#include "commit.h"
  15#include "run-command.h"
  16#include "tag.h"
  17#include "tree.h"
  18#include "tree-walk.h"
  19#include "refs.h"
  20#include "pack-revindex.h"
  21#include "sha1-lookup.h"
  22#include "bulk-checkin.h"
  23#include "streaming.h"
  24#include "dir.h"
  25
  26#ifndef O_NOATIME
  27#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  28#define O_NOATIME 01000000
  29#else
  30#define O_NOATIME 0
  31#endif
  32#endif
  33
  34#define SZ_FMT PRIuMAX
  35static inline uintmax_t sz_fmt(size_t s) { return s; }
  36
  37const unsigned char null_sha1[20];
  38
  39/*
  40 * This is meant to hold a *small* number of objects that you would
  41 * want read_sha1_file() to be able to return, but yet you do not want
  42 * to write them into the object store (e.g. a browse-only
  43 * application).
  44 */
  45static struct cached_object {
  46        unsigned char sha1[20];
  47        enum object_type type;
  48        void *buf;
  49        unsigned long size;
  50} *cached_objects;
  51static int cached_object_nr, cached_object_alloc;
  52
  53static struct cached_object empty_tree = {
  54        EMPTY_TREE_SHA1_BIN_LITERAL,
  55        OBJ_TREE,
  56        "",
  57        0
  58};
  59
  60static struct packed_git *last_found_pack;
  61
  62static struct cached_object *find_cached_object(const unsigned char *sha1)
  63{
  64        int i;
  65        struct cached_object *co = cached_objects;
  66
  67        for (i = 0; i < cached_object_nr; i++, co++) {
  68                if (!hashcmp(co->sha1, sha1))
  69                        return co;
  70        }
  71        if (!hashcmp(sha1, empty_tree.sha1))
  72                return &empty_tree;
  73        return NULL;
  74}
  75
  76int mkdir_in_gitdir(const char *path)
  77{
  78        if (mkdir(path, 0777)) {
  79                int saved_errno = errno;
  80                struct stat st;
  81                struct strbuf sb = STRBUF_INIT;
  82
  83                if (errno != EEXIST)
  84                        return -1;
  85                /*
  86                 * Are we looking at a path in a symlinked worktree
  87                 * whose original repository does not yet have it?
  88                 * e.g. .git/rr-cache pointing at its original
  89                 * repository in which the user hasn't performed any
  90                 * conflict resolution yet?
  91                 */
  92                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
  93                    strbuf_readlink(&sb, path, st.st_size) ||
  94                    !is_absolute_path(sb.buf) ||
  95                    mkdir(sb.buf, 0777)) {
  96                        strbuf_release(&sb);
  97                        errno = saved_errno;
  98                        return -1;
  99                }
 100                strbuf_release(&sb);
 101        }
 102        return adjust_shared_perm(path);
 103}
 104
 105int safe_create_leading_directories(char *path)
 106{
 107        char *pos = path + offset_1st_component(path);
 108        struct stat st;
 109
 110        while (pos) {
 111                pos = strchr(pos, '/');
 112                if (!pos)
 113                        break;
 114                while (*++pos == '/')
 115                        ;
 116                if (!*pos)
 117                        break;
 118                *--pos = '\0';
 119                if (!stat(path, &st)) {
 120                        /* path exists */
 121                        if (!S_ISDIR(st.st_mode)) {
 122                                *pos = '/';
 123                                return -3;
 124                        }
 125                }
 126                else if (mkdir(path, 0777)) {
 127                        if (errno == EEXIST &&
 128                            !stat(path, &st) && S_ISDIR(st.st_mode)) {
 129                                ; /* somebody created it since we checked */
 130                        } else {
 131                                *pos = '/';
 132                                return -1;
 133                        }
 134                }
 135                else if (adjust_shared_perm(path)) {
 136                        *pos = '/';
 137                        return -2;
 138                }
 139                *pos++ = '/';
 140        }
 141        return 0;
 142}
 143
 144int safe_create_leading_directories_const(const char *path)
 145{
 146        /* path points to cache entries, so xstrdup before messing with it */
 147        char *buf = xstrdup(path);
 148        int result = safe_create_leading_directories(buf);
 149        free(buf);
 150        return result;
 151}
 152
 153static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 154{
 155        int i;
 156        for (i = 0; i < 20; i++) {
 157                static char hex[] = "0123456789abcdef";
 158                unsigned int val = sha1[i];
 159                char *pos = pathbuf + i*2 + (i > 0);
 160                *pos++ = hex[val >> 4];
 161                *pos = hex[val & 0xf];
 162        }
 163}
 164
 165/*
 166 * NOTE! This returns a statically allocated buffer, so you have to be
 167 * careful about using it. Do an "xstrdup()" if you need to save the
 168 * filename.
 169 *
 170 * Also note that this returns the location for creating.  Reading
 171 * SHA1 file can happen from any alternate directory listed in the
 172 * DB_ENVIRONMENT environment variable if it is not found in
 173 * the primary object database.
 174 */
 175char *sha1_file_name(const unsigned char *sha1)
 176{
 177        static char buf[PATH_MAX];
 178        const char *objdir;
 179        int len;
 180
 181        objdir = get_object_directory();
 182        len = strlen(objdir);
 183
 184        /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
 185        if (len + 43 > PATH_MAX)
 186                die("insanely long object directory %s", objdir);
 187        memcpy(buf, objdir, len);
 188        buf[len] = '/';
 189        buf[len+3] = '/';
 190        buf[len+42] = '\0';
 191        fill_sha1_path(buf + len + 1, sha1);
 192        return buf;
 193}
 194
 195static char *sha1_get_pack_name(const unsigned char *sha1,
 196                                char **name, char **base, const char *which)
 197{
 198        static const char hex[] = "0123456789abcdef";
 199        char *buf;
 200        int i;
 201
 202        if (!*base) {
 203                const char *sha1_file_directory = get_object_directory();
 204                int len = strlen(sha1_file_directory);
 205                *base = xmalloc(len + 60);
 206                sprintf(*base, "%s/pack/pack-1234567890123456789012345678901234567890.%s",
 207                        sha1_file_directory, which);
 208                *name = *base + len + 11;
 209        }
 210
 211        buf = *name;
 212
 213        for (i = 0; i < 20; i++) {
 214                unsigned int val = *sha1++;
 215                *buf++ = hex[val >> 4];
 216                *buf++ = hex[val & 0xf];
 217        }
 218
 219        return *base;
 220}
 221
 222char *sha1_pack_name(const unsigned char *sha1)
 223{
 224        static char *name, *base;
 225
 226        return sha1_get_pack_name(sha1, &name, &base, "pack");
 227}
 228
 229char *sha1_pack_index_name(const unsigned char *sha1)
 230{
 231        static char *name, *base;
 232
 233        return sha1_get_pack_name(sha1, &name, &base, "idx");
 234}
 235
 236struct alternate_object_database *alt_odb_list;
 237static struct alternate_object_database **alt_odb_tail;
 238
 239static int git_open_noatime(const char *name);
 240
 241/*
 242 * Prepare alternate object database registry.
 243 *
 244 * The variable alt_odb_list points at the list of struct
 245 * alternate_object_database.  The elements on this list come from
 246 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 247 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 248 * whose contents is similar to that environment variable but can be
 249 * LF separated.  Its base points at a statically allocated buffer that
 250 * contains "/the/directory/corresponding/to/.git/objects/...", while
 251 * its name points just after the slash at the end of ".git/objects/"
 252 * in the example above, and has enough space to hold 40-byte hex
 253 * SHA1, an extra slash for the first level indirection, and the
 254 * terminating NUL.
 255 */
 256static int link_alt_odb_entry(const char *entry, const char *relative_base, int depth)
 257{
 258        const char *objdir = get_object_directory();
 259        struct alternate_object_database *ent;
 260        struct alternate_object_database *alt;
 261        int pfxlen, entlen;
 262        struct strbuf pathbuf = STRBUF_INIT;
 263
 264        if (!is_absolute_path(entry) && relative_base) {
 265                strbuf_addstr(&pathbuf, real_path(relative_base));
 266                strbuf_addch(&pathbuf, '/');
 267        }
 268        strbuf_addstr(&pathbuf, entry);
 269
 270        normalize_path_copy(pathbuf.buf, pathbuf.buf);
 271
 272        pfxlen = strlen(pathbuf.buf);
 273
 274        /*
 275         * The trailing slash after the directory name is given by
 276         * this function at the end. Remove duplicates.
 277         */
 278        while (pfxlen && pathbuf.buf[pfxlen-1] == '/')
 279                pfxlen -= 1;
 280
 281        entlen = pfxlen + 43; /* '/' + 2 hex + '/' + 38 hex + NUL */
 282        ent = xmalloc(sizeof(*ent) + entlen);
 283        memcpy(ent->base, pathbuf.buf, pfxlen);
 284        strbuf_release(&pathbuf);
 285
 286        ent->name = ent->base + pfxlen + 1;
 287        ent->base[pfxlen + 3] = '/';
 288        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 289
 290        /* Detect cases where alternate disappeared */
 291        if (!is_directory(ent->base)) {
 292                error("object directory %s does not exist; "
 293                      "check .git/objects/info/alternates.",
 294                      ent->base);
 295                free(ent);
 296                return -1;
 297        }
 298
 299        /* Prevent the common mistake of listing the same
 300         * thing twice, or object directory itself.
 301         */
 302        for (alt = alt_odb_list; alt; alt = alt->next) {
 303                if (!memcmp(ent->base, alt->base, pfxlen)) {
 304                        free(ent);
 305                        return -1;
 306                }
 307        }
 308        if (!strcmp(ent->base, objdir)) {
 309                free(ent);
 310                return -1;
 311        }
 312
 313        /* add the alternate entry */
 314        *alt_odb_tail = ent;
 315        alt_odb_tail = &(ent->next);
 316        ent->next = NULL;
 317
 318        /* recursively add alternates */
 319        read_info_alternates(ent->base, depth + 1);
 320
 321        ent->base[pfxlen] = '/';
 322
 323        return 0;
 324}
 325
 326static void link_alt_odb_entries(const char *alt, int len, int sep,
 327                                 const char *relative_base, int depth)
 328{
 329        struct string_list entries = STRING_LIST_INIT_NODUP;
 330        char *alt_copy;
 331        int i;
 332
 333        if (depth > 5) {
 334                error("%s: ignoring alternate object stores, nesting too deep.",
 335                                relative_base);
 336                return;
 337        }
 338
 339        alt_copy = xmemdupz(alt, len);
 340        string_list_split_in_place(&entries, alt_copy, sep, -1);
 341        for (i = 0; i < entries.nr; i++) {
 342                const char *entry = entries.items[i].string;
 343                if (entry[0] == '\0' || entry[0] == '#')
 344                        continue;
 345                if (!is_absolute_path(entry) && depth) {
 346                        error("%s: ignoring relative alternate object store %s",
 347                                        relative_base, entry);
 348                } else {
 349                        link_alt_odb_entry(entry, relative_base, depth);
 350                }
 351        }
 352        string_list_clear(&entries, 0);
 353        free(alt_copy);
 354}
 355
 356void read_info_alternates(const char * relative_base, int depth)
 357{
 358        char *map;
 359        size_t mapsz;
 360        struct stat st;
 361        const char alt_file_name[] = "info/alternates";
 362        /* Given that relative_base is no longer than PATH_MAX,
 363           ensure that "path" has enough space to append "/", the
 364           file name, "info/alternates", and a trailing NUL.  */
 365        char path[PATH_MAX + 1 + sizeof alt_file_name];
 366        int fd;
 367
 368        sprintf(path, "%s/%s", relative_base, alt_file_name);
 369        fd = git_open_noatime(path);
 370        if (fd < 0)
 371                return;
 372        if (fstat(fd, &st) || (st.st_size == 0)) {
 373                close(fd);
 374                return;
 375        }
 376        mapsz = xsize_t(st.st_size);
 377        map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
 378        close(fd);
 379
 380        link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
 381
 382        munmap(map, mapsz);
 383}
 384
 385void add_to_alternates_file(const char *reference)
 386{
 387        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 388        int fd = hold_lock_file_for_append(lock, git_path("objects/info/alternates"), LOCK_DIE_ON_ERROR);
 389        char *alt = mkpath("%s\n", reference);
 390        write_or_die(fd, alt, strlen(alt));
 391        if (commit_lock_file(lock))
 392                die("could not close alternates file");
 393        if (alt_odb_tail)
 394                link_alt_odb_entries(alt, strlen(alt), '\n', NULL, 0);
 395}
 396
 397void foreach_alt_odb(alt_odb_fn fn, void *cb)
 398{
 399        struct alternate_object_database *ent;
 400
 401        prepare_alt_odb();
 402        for (ent = alt_odb_list; ent; ent = ent->next)
 403                if (fn(ent, cb))
 404                        return;
 405}
 406
 407void prepare_alt_odb(void)
 408{
 409        const char *alt;
 410
 411        if (alt_odb_tail)
 412                return;
 413
 414        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 415        if (!alt) alt = "";
 416
 417        alt_odb_tail = &alt_odb_list;
 418        link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
 419
 420        read_info_alternates(get_object_directory(), 0);
 421}
 422
 423static int has_loose_object_local(const unsigned char *sha1)
 424{
 425        char *name = sha1_file_name(sha1);
 426        return !access(name, F_OK);
 427}
 428
 429int has_loose_object_nonlocal(const unsigned char *sha1)
 430{
 431        struct alternate_object_database *alt;
 432        prepare_alt_odb();
 433        for (alt = alt_odb_list; alt; alt = alt->next) {
 434                fill_sha1_path(alt->name, sha1);
 435                if (!access(alt->base, F_OK))
 436                        return 1;
 437        }
 438        return 0;
 439}
 440
 441static int has_loose_object(const unsigned char *sha1)
 442{
 443        return has_loose_object_local(sha1) ||
 444               has_loose_object_nonlocal(sha1);
 445}
 446
 447static unsigned int pack_used_ctr;
 448static unsigned int pack_mmap_calls;
 449static unsigned int peak_pack_open_windows;
 450static unsigned int pack_open_windows;
 451static unsigned int pack_open_fds;
 452static unsigned int pack_max_fds;
 453static size_t peak_pack_mapped;
 454static size_t pack_mapped;
 455struct packed_git *packed_git;
 456
 457void pack_report(void)
 458{
 459        fprintf(stderr,
 460                "pack_report: getpagesize()            = %10" SZ_FMT "\n"
 461                "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 462                "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
 463                sz_fmt(getpagesize()),
 464                sz_fmt(packed_git_window_size),
 465                sz_fmt(packed_git_limit));
 466        fprintf(stderr,
 467                "pack_report: pack_used_ctr            = %10u\n"
 468                "pack_report: pack_mmap_calls          = %10u\n"
 469                "pack_report: pack_open_windows        = %10u / %10u\n"
 470                "pack_report: pack_mapped              = "
 471                        "%10" SZ_FMT " / %10" SZ_FMT "\n",
 472                pack_used_ctr,
 473                pack_mmap_calls,
 474                pack_open_windows, peak_pack_open_windows,
 475                sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
 476}
 477
 478static int check_packed_git_idx(const char *path,  struct packed_git *p)
 479{
 480        void *idx_map;
 481        struct pack_idx_header *hdr;
 482        size_t idx_size;
 483        uint32_t version, nr, i, *index;
 484        int fd = git_open_noatime(path);
 485        struct stat st;
 486
 487        if (fd < 0)
 488                return -1;
 489        if (fstat(fd, &st)) {
 490                close(fd);
 491                return -1;
 492        }
 493        idx_size = xsize_t(st.st_size);
 494        if (idx_size < 4 * 256 + 20 + 20) {
 495                close(fd);
 496                return error("index file %s is too small", path);
 497        }
 498        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 499        close(fd);
 500
 501        hdr = idx_map;
 502        if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 503                version = ntohl(hdr->idx_version);
 504                if (version < 2 || version > 2) {
 505                        munmap(idx_map, idx_size);
 506                        return error("index file %s is version %"PRIu32
 507                                     " and is not supported by this binary"
 508                                     " (try upgrading GIT to a newer version)",
 509                                     path, version);
 510                }
 511        } else
 512                version = 1;
 513
 514        nr = 0;
 515        index = idx_map;
 516        if (version > 1)
 517                index += 2;  /* skip index header */
 518        for (i = 0; i < 256; i++) {
 519                uint32_t n = ntohl(index[i]);
 520                if (n < nr) {
 521                        munmap(idx_map, idx_size);
 522                        return error("non-monotonic index %s", path);
 523                }
 524                nr = n;
 525        }
 526
 527        if (version == 1) {
 528                /*
 529                 * Total size:
 530                 *  - 256 index entries 4 bytes each
 531                 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 532                 *  - 20-byte SHA1 of the packfile
 533                 *  - 20-byte SHA1 file checksum
 534                 */
 535                if (idx_size != 4*256 + nr * 24 + 20 + 20) {
 536                        munmap(idx_map, idx_size);
 537                        return error("wrong index v1 file size in %s", path);
 538                }
 539        } else if (version == 2) {
 540                /*
 541                 * Minimum size:
 542                 *  - 8 bytes of header
 543                 *  - 256 index entries 4 bytes each
 544                 *  - 20-byte sha1 entry * nr
 545                 *  - 4-byte crc entry * nr
 546                 *  - 4-byte offset entry * nr
 547                 *  - 20-byte SHA1 of the packfile
 548                 *  - 20-byte SHA1 file checksum
 549                 * And after the 4-byte offset table might be a
 550                 * variable sized table containing 8-byte entries
 551                 * for offsets larger than 2^31.
 552                 */
 553                unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
 554                unsigned long max_size = min_size;
 555                if (nr)
 556                        max_size += (nr - 1)*8;
 557                if (idx_size < min_size || idx_size > max_size) {
 558                        munmap(idx_map, idx_size);
 559                        return error("wrong index v2 file size in %s", path);
 560                }
 561                if (idx_size != min_size &&
 562                    /*
 563                     * make sure we can deal with large pack offsets.
 564                     * 31-bit signed offset won't be enough, neither
 565                     * 32-bit unsigned one will be.
 566                     */
 567                    (sizeof(off_t) <= 4)) {
 568                        munmap(idx_map, idx_size);
 569                        return error("pack too large for current definition of off_t in %s", path);
 570                }
 571        }
 572
 573        p->index_version = version;
 574        p->index_data = idx_map;
 575        p->index_size = idx_size;
 576        p->num_objects = nr;
 577        return 0;
 578}
 579
 580int open_pack_index(struct packed_git *p)
 581{
 582        char *idx_name;
 583        int ret;
 584
 585        if (p->index_data)
 586                return 0;
 587
 588        idx_name = xstrdup(p->pack_name);
 589        strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
 590        ret = check_packed_git_idx(idx_name, p);
 591        free(idx_name);
 592        return ret;
 593}
 594
 595static void scan_windows(struct packed_git *p,
 596        struct packed_git **lru_p,
 597        struct pack_window **lru_w,
 598        struct pack_window **lru_l)
 599{
 600        struct pack_window *w, *w_l;
 601
 602        for (w_l = NULL, w = p->windows; w; w = w->next) {
 603                if (!w->inuse_cnt) {
 604                        if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 605                                *lru_p = p;
 606                                *lru_w = w;
 607                                *lru_l = w_l;
 608                        }
 609                }
 610                w_l = w;
 611        }
 612}
 613
 614static int unuse_one_window(struct packed_git *current, int keep_fd)
 615{
 616        struct packed_git *p, *lru_p = NULL;
 617        struct pack_window *lru_w = NULL, *lru_l = NULL;
 618
 619        if (current)
 620                scan_windows(current, &lru_p, &lru_w, &lru_l);
 621        for (p = packed_git; p; p = p->next)
 622                scan_windows(p, &lru_p, &lru_w, &lru_l);
 623        if (lru_p) {
 624                munmap(lru_w->base, lru_w->len);
 625                pack_mapped -= lru_w->len;
 626                if (lru_l)
 627                        lru_l->next = lru_w->next;
 628                else {
 629                        lru_p->windows = lru_w->next;
 630                        if (!lru_p->windows && lru_p->pack_fd != -1
 631                                && lru_p->pack_fd != keep_fd) {
 632                                close(lru_p->pack_fd);
 633                                pack_open_fds--;
 634                                lru_p->pack_fd = -1;
 635                        }
 636                }
 637                free(lru_w);
 638                pack_open_windows--;
 639                return 1;
 640        }
 641        return 0;
 642}
 643
 644void release_pack_memory(size_t need, int fd)
 645{
 646        size_t cur = pack_mapped;
 647        while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd))
 648                ; /* nothing */
 649}
 650
 651void *xmmap(void *start, size_t length,
 652        int prot, int flags, int fd, off_t offset)
 653{
 654        void *ret = mmap(start, length, prot, flags, fd, offset);
 655        if (ret == MAP_FAILED) {
 656                if (!length)
 657                        return NULL;
 658                release_pack_memory(length, fd);
 659                ret = mmap(start, length, prot, flags, fd, offset);
 660                if (ret == MAP_FAILED)
 661                        die_errno("Out of memory? mmap failed");
 662        }
 663        return ret;
 664}
 665
 666void close_pack_windows(struct packed_git *p)
 667{
 668        while (p->windows) {
 669                struct pack_window *w = p->windows;
 670
 671                if (w->inuse_cnt)
 672                        die("pack '%s' still has open windows to it",
 673                            p->pack_name);
 674                munmap(w->base, w->len);
 675                pack_mapped -= w->len;
 676                pack_open_windows--;
 677                p->windows = w->next;
 678                free(w);
 679        }
 680}
 681
 682void unuse_pack(struct pack_window **w_cursor)
 683{
 684        struct pack_window *w = *w_cursor;
 685        if (w) {
 686                w->inuse_cnt--;
 687                *w_cursor = NULL;
 688        }
 689}
 690
 691void close_pack_index(struct packed_git *p)
 692{
 693        if (p->index_data) {
 694                munmap((void *)p->index_data, p->index_size);
 695                p->index_data = NULL;
 696        }
 697}
 698
 699/*
 700 * This is used by git-repack in case a newly created pack happens to
 701 * contain the same set of objects as an existing one.  In that case
 702 * the resulting file might be different even if its name would be the
 703 * same.  It is best to close any reference to the old pack before it is
 704 * replaced on disk.  Of course no index pointers nor windows for given pack
 705 * must subsist at this point.  If ever objects from this pack are requested
 706 * again, the new version of the pack will be reinitialized through
 707 * reprepare_packed_git().
 708 */
 709void free_pack_by_name(const char *pack_name)
 710{
 711        struct packed_git *p, **pp = &packed_git;
 712
 713        while (*pp) {
 714                p = *pp;
 715                if (strcmp(pack_name, p->pack_name) == 0) {
 716                        clear_delta_base_cache();
 717                        close_pack_windows(p);
 718                        if (p->pack_fd != -1) {
 719                                close(p->pack_fd);
 720                                pack_open_fds--;
 721                        }
 722                        close_pack_index(p);
 723                        free(p->bad_object_sha1);
 724                        *pp = p->next;
 725                        if (last_found_pack == p)
 726                                last_found_pack = NULL;
 727                        free(p);
 728                        return;
 729                }
 730                pp = &p->next;
 731        }
 732}
 733
 734static unsigned int get_max_fd_limit(void)
 735{
 736#ifdef RLIMIT_NOFILE
 737        struct rlimit lim;
 738
 739        if (getrlimit(RLIMIT_NOFILE, &lim))
 740                die_errno("cannot get RLIMIT_NOFILE");
 741
 742        return lim.rlim_cur;
 743#elif defined(_SC_OPEN_MAX)
 744        return sysconf(_SC_OPEN_MAX);
 745#elif defined(OPEN_MAX)
 746        return OPEN_MAX;
 747#else
 748        return 1; /* see the caller ;-) */
 749#endif
 750}
 751
 752/*
 753 * Do not call this directly as this leaks p->pack_fd on error return;
 754 * call open_packed_git() instead.
 755 */
 756static int open_packed_git_1(struct packed_git *p)
 757{
 758        struct stat st;
 759        struct pack_header hdr;
 760        unsigned char sha1[20];
 761        unsigned char *idx_sha1;
 762        long fd_flag;
 763
 764        if (!p->index_data && open_pack_index(p))
 765                return error("packfile %s index unavailable", p->pack_name);
 766
 767        if (!pack_max_fds) {
 768                unsigned int max_fds = get_max_fd_limit();
 769
 770                /* Save 3 for stdin/stdout/stderr, 22 for work */
 771                if (25 < max_fds)
 772                        pack_max_fds = max_fds - 25;
 773                else
 774                        pack_max_fds = 1;
 775        }
 776
 777        while (pack_max_fds <= pack_open_fds && unuse_one_window(NULL, -1))
 778                ; /* nothing */
 779
 780        p->pack_fd = git_open_noatime(p->pack_name);
 781        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 782                return -1;
 783        pack_open_fds++;
 784
 785        /* If we created the struct before we had the pack we lack size. */
 786        if (!p->pack_size) {
 787                if (!S_ISREG(st.st_mode))
 788                        return error("packfile %s not a regular file", p->pack_name);
 789                p->pack_size = st.st_size;
 790        } else if (p->pack_size != st.st_size)
 791                return error("packfile %s size changed", p->pack_name);
 792
 793        /* We leave these file descriptors open with sliding mmap;
 794         * there is no point keeping them open across exec(), though.
 795         */
 796        fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 797        if (fd_flag < 0)
 798                return error("cannot determine file descriptor flags");
 799        fd_flag |= FD_CLOEXEC;
 800        if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 801                return error("cannot set FD_CLOEXEC");
 802
 803        /* Verify we recognize this pack file format. */
 804        if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 805                return error("file %s is far too short to be a packfile", p->pack_name);
 806        if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 807                return error("file %s is not a GIT packfile", p->pack_name);
 808        if (!pack_version_ok(hdr.hdr_version))
 809                return error("packfile %s is version %"PRIu32" and not"
 810                        " supported (try upgrading GIT to a newer version)",
 811                        p->pack_name, ntohl(hdr.hdr_version));
 812
 813        /* Verify the pack matches its index. */
 814        if (p->num_objects != ntohl(hdr.hdr_entries))
 815                return error("packfile %s claims to have %"PRIu32" objects"
 816                             " while index indicates %"PRIu32" objects",
 817                             p->pack_name, ntohl(hdr.hdr_entries),
 818                             p->num_objects);
 819        if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
 820                return error("end of packfile %s is unavailable", p->pack_name);
 821        if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
 822                return error("packfile %s signature is unavailable", p->pack_name);
 823        idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
 824        if (hashcmp(sha1, idx_sha1))
 825                return error("packfile %s does not match index", p->pack_name);
 826        return 0;
 827}
 828
 829static int open_packed_git(struct packed_git *p)
 830{
 831        if (!open_packed_git_1(p))
 832                return 0;
 833        if (p->pack_fd != -1) {
 834                close(p->pack_fd);
 835                pack_open_fds--;
 836                p->pack_fd = -1;
 837        }
 838        return -1;
 839}
 840
 841static int in_window(struct pack_window *win, off_t offset)
 842{
 843        /* We must promise at least 20 bytes (one hash) after the
 844         * offset is available from this window, otherwise the offset
 845         * is not actually in this window and a different window (which
 846         * has that one hash excess) must be used.  This is to support
 847         * the object header and delta base parsing routines below.
 848         */
 849        off_t win_off = win->offset;
 850        return win_off <= offset
 851                && (offset + 20) <= (win_off + win->len);
 852}
 853
 854unsigned char *use_pack(struct packed_git *p,
 855                struct pack_window **w_cursor,
 856                off_t offset,
 857                unsigned long *left)
 858{
 859        struct pack_window *win = *w_cursor;
 860
 861        /* Since packfiles end in a hash of their content and it's
 862         * pointless to ask for an offset into the middle of that
 863         * hash, and the in_window function above wouldn't match
 864         * don't allow an offset too close to the end of the file.
 865         */
 866        if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 867                die("packfile %s cannot be accessed", p->pack_name);
 868        if (offset > (p->pack_size - 20))
 869                die("offset beyond end of packfile (truncated pack?)");
 870
 871        if (!win || !in_window(win, offset)) {
 872                if (win)
 873                        win->inuse_cnt--;
 874                for (win = p->windows; win; win = win->next) {
 875                        if (in_window(win, offset))
 876                                break;
 877                }
 878                if (!win) {
 879                        size_t window_align = packed_git_window_size / 2;
 880                        off_t len;
 881
 882                        if (p->pack_fd == -1 && open_packed_git(p))
 883                                die("packfile %s cannot be accessed", p->pack_name);
 884
 885                        win = xcalloc(1, sizeof(*win));
 886                        win->offset = (offset / window_align) * window_align;
 887                        len = p->pack_size - win->offset;
 888                        if (len > packed_git_window_size)
 889                                len = packed_git_window_size;
 890                        win->len = (size_t)len;
 891                        pack_mapped += win->len;
 892                        while (packed_git_limit < pack_mapped
 893                                && unuse_one_window(p, p->pack_fd))
 894                                ; /* nothing */
 895                        win->base = xmmap(NULL, win->len,
 896                                PROT_READ, MAP_PRIVATE,
 897                                p->pack_fd, win->offset);
 898                        if (win->base == MAP_FAILED)
 899                                die("packfile %s cannot be mapped: %s",
 900                                        p->pack_name,
 901                                        strerror(errno));
 902                        if (!win->offset && win->len == p->pack_size
 903                                && !p->do_not_close) {
 904                                close(p->pack_fd);
 905                                pack_open_fds--;
 906                                p->pack_fd = -1;
 907                        }
 908                        pack_mmap_calls++;
 909                        pack_open_windows++;
 910                        if (pack_mapped > peak_pack_mapped)
 911                                peak_pack_mapped = pack_mapped;
 912                        if (pack_open_windows > peak_pack_open_windows)
 913                                peak_pack_open_windows = pack_open_windows;
 914                        win->next = p->windows;
 915                        p->windows = win;
 916                }
 917        }
 918        if (win != *w_cursor) {
 919                win->last_used = pack_used_ctr++;
 920                win->inuse_cnt++;
 921                *w_cursor = win;
 922        }
 923        offset -= win->offset;
 924        if (left)
 925                *left = win->len - xsize_t(offset);
 926        return win->base + offset;
 927}
 928
 929static struct packed_git *alloc_packed_git(int extra)
 930{
 931        struct packed_git *p = xmalloc(sizeof(*p) + extra);
 932        memset(p, 0, sizeof(*p));
 933        p->pack_fd = -1;
 934        return p;
 935}
 936
 937static void try_to_free_pack_memory(size_t size)
 938{
 939        release_pack_memory(size, -1);
 940}
 941
 942struct packed_git *add_packed_git(const char *path, int path_len, int local)
 943{
 944        static int have_set_try_to_free_routine;
 945        struct stat st;
 946        struct packed_git *p = alloc_packed_git(path_len + 2);
 947
 948        if (!have_set_try_to_free_routine) {
 949                have_set_try_to_free_routine = 1;
 950                set_try_to_free_routine(try_to_free_pack_memory);
 951        }
 952
 953        /*
 954         * Make sure a corresponding .pack file exists and that
 955         * the index looks sane.
 956         */
 957        path_len -= strlen(".idx");
 958        if (path_len < 1) {
 959                free(p);
 960                return NULL;
 961        }
 962        memcpy(p->pack_name, path, path_len);
 963
 964        strcpy(p->pack_name + path_len, ".keep");
 965        if (!access(p->pack_name, F_OK))
 966                p->pack_keep = 1;
 967
 968        strcpy(p->pack_name + path_len, ".pack");
 969        if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 970                free(p);
 971                return NULL;
 972        }
 973
 974        /* ok, it looks sane as far as we can check without
 975         * actually mapping the pack file.
 976         */
 977        p->pack_size = st.st_size;
 978        p->pack_local = local;
 979        p->mtime = st.st_mtime;
 980        if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
 981                hashclr(p->sha1);
 982        return p;
 983}
 984
 985struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 986{
 987        const char *path = sha1_pack_name(sha1);
 988        struct packed_git *p = alloc_packed_git(strlen(path) + 1);
 989
 990        strcpy(p->pack_name, path);
 991        hashcpy(p->sha1, sha1);
 992        if (check_packed_git_idx(idx_path, p)) {
 993                free(p);
 994                return NULL;
 995        }
 996
 997        return p;
 998}
 999
1000void install_packed_git(struct packed_git *pack)
1001{
1002        if (pack->pack_fd != -1)
1003                pack_open_fds++;
1004
1005        pack->next = packed_git;
1006        packed_git = pack;
1007}
1008
1009void (*report_garbage)(const char *desc, const char *path);
1010
1011static void report_helper(const struct string_list *list,
1012                          int seen_bits, int first, int last)
1013{
1014        const char *msg;
1015        switch (seen_bits) {
1016        case 0:
1017                msg = "no corresponding .idx nor .pack";
1018                break;
1019        case 1:
1020                msg = "no corresponding .idx";
1021                break;
1022        case 2:
1023                msg = "no corresponding .pack";
1024                break;
1025        default:
1026                return;
1027        }
1028        for (; first < last; first++)
1029                report_garbage(msg, list->items[first].string);
1030}
1031
1032static void report_pack_garbage(struct string_list *list)
1033{
1034        int i, baselen = -1, first = 0, seen_bits = 0;
1035
1036        if (!report_garbage)
1037                return;
1038
1039        sort_string_list(list);
1040
1041        for (i = 0; i < list->nr; i++) {
1042                const char *path = list->items[i].string;
1043                if (baselen != -1 &&
1044                    strncmp(path, list->items[first].string, baselen)) {
1045                        report_helper(list, seen_bits, first, i);
1046                        baselen = -1;
1047                        seen_bits = 0;
1048                }
1049                if (baselen == -1) {
1050                        const char *dot = strrchr(path, '.');
1051                        if (!dot) {
1052                                report_garbage("garbage found", path);
1053                                continue;
1054                        }
1055                        baselen = dot - path + 1;
1056                        first = i;
1057                }
1058                if (!strcmp(path + baselen, "pack"))
1059                        seen_bits |= 1;
1060                else if (!strcmp(path + baselen, "idx"))
1061                        seen_bits |= 2;
1062        }
1063        report_helper(list, seen_bits, first, list->nr);
1064}
1065
1066static void prepare_packed_git_one(char *objdir, int local)
1067{
1068        /* Ensure that this buffer is large enough so that we can
1069           append "/pack/" without clobbering the stack even if
1070           strlen(objdir) were PATH_MAX.  */
1071        char path[PATH_MAX + 1 + 4 + 1 + 1];
1072        int len;
1073        DIR *dir;
1074        struct dirent *de;
1075        struct string_list garbage = STRING_LIST_INIT_DUP;
1076
1077        sprintf(path, "%s/pack", objdir);
1078        len = strlen(path);
1079        dir = opendir(path);
1080        if (!dir) {
1081                if (errno != ENOENT)
1082                        error("unable to open object pack directory: %s: %s",
1083                              path, strerror(errno));
1084                return;
1085        }
1086        path[len++] = '/';
1087        while ((de = readdir(dir)) != NULL) {
1088                int namelen = strlen(de->d_name);
1089                struct packed_git *p;
1090
1091                if (len + namelen + 1 > sizeof(path)) {
1092                        if (report_garbage) {
1093                                struct strbuf sb = STRBUF_INIT;
1094                                strbuf_addf(&sb, "%.*s/%s", len - 1, path, de->d_name);
1095                                report_garbage("path too long", sb.buf);
1096                                strbuf_release(&sb);
1097                        }
1098                        continue;
1099                }
1100
1101                if (is_dot_or_dotdot(de->d_name))
1102                        continue;
1103
1104                strcpy(path + len, de->d_name);
1105
1106                if (has_extension(de->d_name, ".idx")) {
1107                        /* Don't reopen a pack we already have. */
1108                        for (p = packed_git; p; p = p->next) {
1109                                if (!memcmp(path, p->pack_name, len + namelen - 4))
1110                                        break;
1111                        }
1112                        if (p == NULL &&
1113                            /*
1114                             * See if it really is a valid .idx file with
1115                             * corresponding .pack file that we can map.
1116                             */
1117                            (p = add_packed_git(path, len + namelen, local)) != NULL)
1118                                install_packed_git(p);
1119                }
1120
1121                if (!report_garbage)
1122                        continue;
1123
1124                if (has_extension(de->d_name, ".idx") ||
1125                    has_extension(de->d_name, ".pack") ||
1126                    has_extension(de->d_name, ".keep"))
1127                        string_list_append(&garbage, path);
1128                else
1129                        report_garbage("garbage found", path);
1130        }
1131        closedir(dir);
1132        report_pack_garbage(&garbage);
1133        string_list_clear(&garbage, 0);
1134}
1135
1136static int sort_pack(const void *a_, const void *b_)
1137{
1138        struct packed_git *a = *((struct packed_git **)a_);
1139        struct packed_git *b = *((struct packed_git **)b_);
1140        int st;
1141
1142        /*
1143         * Local packs tend to contain objects specific to our
1144         * variant of the project than remote ones.  In addition,
1145         * remote ones could be on a network mounted filesystem.
1146         * Favor local ones for these reasons.
1147         */
1148        st = a->pack_local - b->pack_local;
1149        if (st)
1150                return -st;
1151
1152        /*
1153         * Younger packs tend to contain more recent objects,
1154         * and more recent objects tend to get accessed more
1155         * often.
1156         */
1157        if (a->mtime < b->mtime)
1158                return 1;
1159        else if (a->mtime == b->mtime)
1160                return 0;
1161        return -1;
1162}
1163
1164static void rearrange_packed_git(void)
1165{
1166        struct packed_git **ary, *p;
1167        int i, n;
1168
1169        for (n = 0, p = packed_git; p; p = p->next)
1170                n++;
1171        if (n < 2)
1172                return;
1173
1174        /* prepare an array of packed_git for easier sorting */
1175        ary = xcalloc(n, sizeof(struct packed_git *));
1176        for (n = 0, p = packed_git; p; p = p->next)
1177                ary[n++] = p;
1178
1179        qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1180
1181        /* link them back again */
1182        for (i = 0; i < n - 1; i++)
1183                ary[i]->next = ary[i + 1];
1184        ary[n - 1]->next = NULL;
1185        packed_git = ary[0];
1186
1187        free(ary);
1188}
1189
1190static int prepare_packed_git_run_once = 0;
1191void prepare_packed_git(void)
1192{
1193        struct alternate_object_database *alt;
1194
1195        if (prepare_packed_git_run_once)
1196                return;
1197        prepare_packed_git_one(get_object_directory(), 1);
1198        prepare_alt_odb();
1199        for (alt = alt_odb_list; alt; alt = alt->next) {
1200                alt->name[-1] = 0;
1201                prepare_packed_git_one(alt->base, 0);
1202                alt->name[-1] = '/';
1203        }
1204        rearrange_packed_git();
1205        prepare_packed_git_run_once = 1;
1206}
1207
1208void reprepare_packed_git(void)
1209{
1210        discard_revindex();
1211        prepare_packed_git_run_once = 0;
1212        prepare_packed_git();
1213}
1214
1215static void mark_bad_packed_object(struct packed_git *p,
1216                                   const unsigned char *sha1)
1217{
1218        unsigned i;
1219        for (i = 0; i < p->num_bad_objects; i++)
1220                if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1221                        return;
1222        p->bad_object_sha1 = xrealloc(p->bad_object_sha1, 20 * (p->num_bad_objects + 1));
1223        hashcpy(p->bad_object_sha1 + 20 * p->num_bad_objects, sha1);
1224        p->num_bad_objects++;
1225}
1226
1227static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1228{
1229        struct packed_git *p;
1230        unsigned i;
1231
1232        for (p = packed_git; p; p = p->next)
1233                for (i = 0; i < p->num_bad_objects; i++)
1234                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1235                                return p;
1236        return NULL;
1237}
1238
1239/*
1240 * With an in-core object data in "map", rehash it to make sure the
1241 * object name actually matches "sha1" to detect object corruption.
1242 * With "map" == NULL, try reading the object named with "sha1" using
1243 * the streaming interface and rehash it to do the same.
1244 */
1245int check_sha1_signature(const unsigned char *sha1, void *map,
1246                         unsigned long size, const char *type)
1247{
1248        unsigned char real_sha1[20];
1249        enum object_type obj_type;
1250        struct git_istream *st;
1251        git_SHA_CTX c;
1252        char hdr[32];
1253        int hdrlen;
1254
1255        if (map) {
1256                hash_sha1_file(map, size, type, real_sha1);
1257                return hashcmp(sha1, real_sha1) ? -1 : 0;
1258        }
1259
1260        st = open_istream(sha1, &obj_type, &size, NULL);
1261        if (!st)
1262                return -1;
1263
1264        /* Generate the header */
1265        hdrlen = sprintf(hdr, "%s %lu", typename(obj_type), size) + 1;
1266
1267        /* Sha1.. */
1268        git_SHA1_Init(&c);
1269        git_SHA1_Update(&c, hdr, hdrlen);
1270        for (;;) {
1271                char buf[1024 * 16];
1272                ssize_t readlen = read_istream(st, buf, sizeof(buf));
1273
1274                if (!readlen)
1275                        break;
1276                git_SHA1_Update(&c, buf, readlen);
1277        }
1278        git_SHA1_Final(real_sha1, &c);
1279        close_istream(st);
1280        return hashcmp(sha1, real_sha1) ? -1 : 0;
1281}
1282
1283static int git_open_noatime(const char *name)
1284{
1285        static int sha1_file_open_flag = O_NOATIME;
1286
1287        for (;;) {
1288                int fd = open(name, O_RDONLY | sha1_file_open_flag);
1289                if (fd >= 0)
1290                        return fd;
1291
1292                /* Might the failure be due to O_NOATIME? */
1293                if (errno != ENOENT && sha1_file_open_flag) {
1294                        sha1_file_open_flag = 0;
1295                        continue;
1296                }
1297
1298                return -1;
1299        }
1300}
1301
1302static int open_sha1_file(const unsigned char *sha1)
1303{
1304        int fd;
1305        char *name = sha1_file_name(sha1);
1306        struct alternate_object_database *alt;
1307
1308        fd = git_open_noatime(name);
1309        if (fd >= 0)
1310                return fd;
1311
1312        prepare_alt_odb();
1313        errno = ENOENT;
1314        for (alt = alt_odb_list; alt; alt = alt->next) {
1315                name = alt->name;
1316                fill_sha1_path(name, sha1);
1317                fd = git_open_noatime(alt->base);
1318                if (fd >= 0)
1319                        return fd;
1320        }
1321        return -1;
1322}
1323
1324void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1325{
1326        void *map;
1327        int fd;
1328
1329        fd = open_sha1_file(sha1);
1330        map = NULL;
1331        if (fd >= 0) {
1332                struct stat st;
1333
1334                if (!fstat(fd, &st)) {
1335                        *size = xsize_t(st.st_size);
1336                        if (!*size) {
1337                                /* mmap() is forbidden on empty files */
1338                                error("object file %s is empty", sha1_file_name(sha1));
1339                                return NULL;
1340                        }
1341                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1342                }
1343                close(fd);
1344        }
1345        return map;
1346}
1347
1348/*
1349 * There used to be a second loose object header format which
1350 * was meant to mimic the in-pack format, allowing for direct
1351 * copy of the object data.  This format turned up not to be
1352 * really worth it and we no longer write loose objects in that
1353 * format.
1354 */
1355static int experimental_loose_object(unsigned char *map)
1356{
1357        unsigned int word;
1358
1359        /*
1360         * We must determine if the buffer contains the standard
1361         * zlib-deflated stream or the experimental format based
1362         * on the in-pack object format. Compare the header byte
1363         * for each format:
1364         *
1365         * RFC1950 zlib w/ deflate : 0www1000 : 0 <= www <= 7
1366         * Experimental pack-based : Stttssss : ttt = 1,2,3,4
1367         *
1368         * If bit 7 is clear and bits 0-3 equal 8, the buffer MUST be
1369         * in standard loose-object format, UNLESS it is a Git-pack
1370         * format object *exactly* 8 bytes in size when inflated.
1371         *
1372         * However, RFC1950 also specifies that the 1st 16-bit word
1373         * must be divisible by 31 - this checksum tells us our buffer
1374         * is in the standard format, giving a false positive only if
1375         * the 1st word of the Git-pack format object happens to be
1376         * divisible by 31, ie:
1377         *      ((byte0 * 256) + byte1) % 31 = 0
1378         *   =>        0ttt10000www1000 % 31 = 0
1379         *
1380         * As it happens, this case can only arise for www=3 & ttt=1
1381         * - ie, a Commit object, which would have to be 8 bytes in
1382         * size. As no Commit can be that small, we find that the
1383         * combination of these two criteria (bitmask & checksum)
1384         * can always correctly determine the buffer format.
1385         */
1386        word = (map[0] << 8) + map[1];
1387        if ((map[0] & 0x8F) == 0x08 && !(word % 31))
1388                return 0;
1389        else
1390                return 1;
1391}
1392
1393unsigned long unpack_object_header_buffer(const unsigned char *buf,
1394                unsigned long len, enum object_type *type, unsigned long *sizep)
1395{
1396        unsigned shift;
1397        unsigned long size, c;
1398        unsigned long used = 0;
1399
1400        c = buf[used++];
1401        *type = (c >> 4) & 7;
1402        size = c & 15;
1403        shift = 4;
1404        while (c & 0x80) {
1405                if (len <= used || bitsizeof(long) <= shift) {
1406                        error("bad object header");
1407                        size = used = 0;
1408                        break;
1409                }
1410                c = buf[used++];
1411                size += (c & 0x7f) << shift;
1412                shift += 7;
1413        }
1414        *sizep = size;
1415        return used;
1416}
1417
1418int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1419{
1420        unsigned long size, used;
1421        static const char valid_loose_object_type[8] = {
1422                0, /* OBJ_EXT */
1423                1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
1424                0, /* "delta" and others are invalid in a loose object */
1425        };
1426        enum object_type type;
1427
1428        /* Get the data stream */
1429        memset(stream, 0, sizeof(*stream));
1430        stream->next_in = map;
1431        stream->avail_in = mapsize;
1432        stream->next_out = buffer;
1433        stream->avail_out = bufsiz;
1434
1435        if (experimental_loose_object(map)) {
1436                /*
1437                 * The old experimental format we no longer produce;
1438                 * we can still read it.
1439                 */
1440                used = unpack_object_header_buffer(map, mapsize, &type, &size);
1441                if (!used || !valid_loose_object_type[type])
1442                        return -1;
1443                map += used;
1444                mapsize -= used;
1445
1446                /* Set up the stream for the rest.. */
1447                stream->next_in = map;
1448                stream->avail_in = mapsize;
1449                git_inflate_init(stream);
1450
1451                /* And generate the fake traditional header */
1452                stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
1453                                                 typename(type), size);
1454                return 0;
1455        }
1456        git_inflate_init(stream);
1457        return git_inflate(stream, 0);
1458}
1459
1460static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1461{
1462        int bytes = strlen(buffer) + 1;
1463        unsigned char *buf = xmallocz(size);
1464        unsigned long n;
1465        int status = Z_OK;
1466
1467        n = stream->total_out - bytes;
1468        if (n > size)
1469                n = size;
1470        memcpy(buf, (char *) buffer + bytes, n);
1471        bytes = n;
1472        if (bytes <= size) {
1473                /*
1474                 * The above condition must be (bytes <= size), not
1475                 * (bytes < size).  In other words, even though we
1476                 * expect no more output and set avail_out to zero,
1477                 * the input zlib stream may have bytes that express
1478                 * "this concludes the stream", and we *do* want to
1479                 * eat that input.
1480                 *
1481                 * Otherwise we would not be able to test that we
1482                 * consumed all the input to reach the expected size;
1483                 * we also want to check that zlib tells us that all
1484                 * went well with status == Z_STREAM_END at the end.
1485                 */
1486                stream->next_out = buf + bytes;
1487                stream->avail_out = size - bytes;
1488                while (status == Z_OK)
1489                        status = git_inflate(stream, Z_FINISH);
1490        }
1491        if (status == Z_STREAM_END && !stream->avail_in) {
1492                git_inflate_end(stream);
1493                return buf;
1494        }
1495
1496        if (status < 0)
1497                error("corrupt loose object '%s'", sha1_to_hex(sha1));
1498        else if (stream->avail_in)
1499                error("garbage at end of loose object '%s'",
1500                      sha1_to_hex(sha1));
1501        free(buf);
1502        return NULL;
1503}
1504
1505/*
1506 * We used to just use "sscanf()", but that's actually way
1507 * too permissive for what we want to check. So do an anal
1508 * object header parse by hand.
1509 */
1510int parse_sha1_header(const char *hdr, unsigned long *sizep)
1511{
1512        char type[10];
1513        int i;
1514        unsigned long size;
1515
1516        /*
1517         * The type can be at most ten bytes (including the
1518         * terminating '\0' that we add), and is followed by
1519         * a space.
1520         */
1521        i = 0;
1522        for (;;) {
1523                char c = *hdr++;
1524                if (c == ' ')
1525                        break;
1526                type[i++] = c;
1527                if (i >= sizeof(type))
1528                        return -1;
1529        }
1530        type[i] = 0;
1531
1532        /*
1533         * The length must follow immediately, and be in canonical
1534         * decimal format (ie "010" is not valid).
1535         */
1536        size = *hdr++ - '0';
1537        if (size > 9)
1538                return -1;
1539        if (size) {
1540                for (;;) {
1541                        unsigned long c = *hdr - '0';
1542                        if (c > 9)
1543                                break;
1544                        hdr++;
1545                        size = size * 10 + c;
1546                }
1547        }
1548        *sizep = size;
1549
1550        /*
1551         * The length must be followed by a zero byte
1552         */
1553        return *hdr ? -1 : type_from_string(type);
1554}
1555
1556static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1557{
1558        int ret;
1559        git_zstream stream;
1560        char hdr[8192];
1561
1562        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1563        if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1564                return NULL;
1565
1566        return unpack_sha1_rest(&stream, hdr, *size, sha1);
1567}
1568
1569unsigned long get_size_from_delta(struct packed_git *p,
1570                                  struct pack_window **w_curs,
1571                                  off_t curpos)
1572{
1573        const unsigned char *data;
1574        unsigned char delta_head[20], *in;
1575        git_zstream stream;
1576        int st;
1577
1578        memset(&stream, 0, sizeof(stream));
1579        stream.next_out = delta_head;
1580        stream.avail_out = sizeof(delta_head);
1581
1582        git_inflate_init(&stream);
1583        do {
1584                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1585                stream.next_in = in;
1586                st = git_inflate(&stream, Z_FINISH);
1587                curpos += stream.next_in - in;
1588        } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1589                 stream.total_out < sizeof(delta_head));
1590        git_inflate_end(&stream);
1591        if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1592                error("delta data unpack-initial failed");
1593                return 0;
1594        }
1595
1596        /* Examine the initial part of the delta to figure out
1597         * the result size.
1598         */
1599        data = delta_head;
1600
1601        /* ignore base size */
1602        get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1603
1604        /* Read the result size */
1605        return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1606}
1607
1608static off_t get_delta_base(struct packed_git *p,
1609                                    struct pack_window **w_curs,
1610                                    off_t *curpos,
1611                                    enum object_type type,
1612                                    off_t delta_obj_offset)
1613{
1614        unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1615        off_t base_offset;
1616
1617        /* use_pack() assured us we have [base_info, base_info + 20)
1618         * as a range that we can look at without walking off the
1619         * end of the mapped window.  Its actually the hash size
1620         * that is assured.  An OFS_DELTA longer than the hash size
1621         * is stupid, as then a REF_DELTA would be smaller to store.
1622         */
1623        if (type == OBJ_OFS_DELTA) {
1624                unsigned used = 0;
1625                unsigned char c = base_info[used++];
1626                base_offset = c & 127;
1627                while (c & 128) {
1628                        base_offset += 1;
1629                        if (!base_offset || MSB(base_offset, 7))
1630                                return 0;  /* overflow */
1631                        c = base_info[used++];
1632                        base_offset = (base_offset << 7) + (c & 127);
1633                }
1634                base_offset = delta_obj_offset - base_offset;
1635                if (base_offset <= 0 || base_offset >= delta_obj_offset)
1636                        return 0;  /* out of bound */
1637                *curpos += used;
1638        } else if (type == OBJ_REF_DELTA) {
1639                /* The base entry _must_ be in the same pack */
1640                base_offset = find_pack_entry_one(base_info, p);
1641                *curpos += 20;
1642        } else
1643                die("I am totally screwed");
1644        return base_offset;
1645}
1646
1647/* forward declaration for a mutually recursive function */
1648static int packed_object_info(struct packed_git *p, off_t offset,
1649                              unsigned long *sizep, int *rtype);
1650
1651static int packed_delta_info(struct packed_git *p,
1652                             struct pack_window **w_curs,
1653                             off_t curpos,
1654                             enum object_type type,
1655                             off_t obj_offset,
1656                             unsigned long *sizep)
1657{
1658        off_t base_offset;
1659
1660        base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1661        if (!base_offset)
1662                return OBJ_BAD;
1663        type = packed_object_info(p, base_offset, NULL, NULL);
1664        if (type <= OBJ_NONE) {
1665                struct revindex_entry *revidx;
1666                const unsigned char *base_sha1;
1667                revidx = find_pack_revindex(p, base_offset);
1668                if (!revidx)
1669                        return OBJ_BAD;
1670                base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1671                mark_bad_packed_object(p, base_sha1);
1672                type = sha1_object_info(base_sha1, NULL);
1673                if (type <= OBJ_NONE)
1674                        return OBJ_BAD;
1675        }
1676
1677        /* We choose to only get the type of the base object and
1678         * ignore potentially corrupt pack file that expects the delta
1679         * based on a base with a wrong size.  This saves tons of
1680         * inflate() calls.
1681         */
1682        if (sizep) {
1683                *sizep = get_size_from_delta(p, w_curs, curpos);
1684                if (*sizep == 0)
1685                        type = OBJ_BAD;
1686        }
1687
1688        return type;
1689}
1690
1691int unpack_object_header(struct packed_git *p,
1692                         struct pack_window **w_curs,
1693                         off_t *curpos,
1694                         unsigned long *sizep)
1695{
1696        unsigned char *base;
1697        unsigned long left;
1698        unsigned long used;
1699        enum object_type type;
1700
1701        /* use_pack() assures us we have [base, base + 20) available
1702         * as a range that we can look at.  (Its actually the hash
1703         * size that is assured.)  With our object header encoding
1704         * the maximum deflated object size is 2^137, which is just
1705         * insane, so we know won't exceed what we have been given.
1706         */
1707        base = use_pack(p, w_curs, *curpos, &left);
1708        used = unpack_object_header_buffer(base, left, &type, sizep);
1709        if (!used) {
1710                type = OBJ_BAD;
1711        } else
1712                *curpos += used;
1713
1714        return type;
1715}
1716
1717static int packed_object_info(struct packed_git *p, off_t obj_offset,
1718                              unsigned long *sizep, int *rtype)
1719{
1720        struct pack_window *w_curs = NULL;
1721        unsigned long size;
1722        off_t curpos = obj_offset;
1723        enum object_type type;
1724
1725        type = unpack_object_header(p, &w_curs, &curpos, &size);
1726        if (rtype)
1727                *rtype = type; /* representation type */
1728
1729        switch (type) {
1730        case OBJ_OFS_DELTA:
1731        case OBJ_REF_DELTA:
1732                type = packed_delta_info(p, &w_curs, curpos,
1733                                         type, obj_offset, sizep);
1734                break;
1735        case OBJ_COMMIT:
1736        case OBJ_TREE:
1737        case OBJ_BLOB:
1738        case OBJ_TAG:
1739                if (sizep)
1740                        *sizep = size;
1741                break;
1742        default:
1743                error("unknown object type %i at offset %"PRIuMAX" in %s",
1744                      type, (uintmax_t)obj_offset, p->pack_name);
1745                type = OBJ_BAD;
1746        }
1747        unuse_pack(&w_curs);
1748        return type;
1749}
1750
1751static void *unpack_compressed_entry(struct packed_git *p,
1752                                    struct pack_window **w_curs,
1753                                    off_t curpos,
1754                                    unsigned long size)
1755{
1756        int st;
1757        git_zstream stream;
1758        unsigned char *buffer, *in;
1759
1760        buffer = xmallocz(size);
1761        memset(&stream, 0, sizeof(stream));
1762        stream.next_out = buffer;
1763        stream.avail_out = size + 1;
1764
1765        git_inflate_init(&stream);
1766        do {
1767                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1768                stream.next_in = in;
1769                st = git_inflate(&stream, Z_FINISH);
1770                if (!stream.avail_out)
1771                        break; /* the payload is larger than it should be */
1772                curpos += stream.next_in - in;
1773        } while (st == Z_OK || st == Z_BUF_ERROR);
1774        git_inflate_end(&stream);
1775        if ((st != Z_STREAM_END) || stream.total_out != size) {
1776                free(buffer);
1777                return NULL;
1778        }
1779
1780        return buffer;
1781}
1782
1783#define MAX_DELTA_CACHE (256)
1784
1785static size_t delta_base_cached;
1786
1787static struct delta_base_cache_lru_list {
1788        struct delta_base_cache_lru_list *prev;
1789        struct delta_base_cache_lru_list *next;
1790} delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
1791
1792static struct delta_base_cache_entry {
1793        struct delta_base_cache_lru_list lru;
1794        void *data;
1795        struct packed_git *p;
1796        off_t base_offset;
1797        unsigned long size;
1798        enum object_type type;
1799} delta_base_cache[MAX_DELTA_CACHE];
1800
1801static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
1802{
1803        unsigned long hash;
1804
1805        hash = (unsigned long)p + (unsigned long)base_offset;
1806        hash += (hash >> 8) + (hash >> 16);
1807        return hash % MAX_DELTA_CACHE;
1808}
1809
1810static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1811{
1812        unsigned long hash = pack_entry_hash(p, base_offset);
1813        struct delta_base_cache_entry *ent = delta_base_cache + hash;
1814        return (ent->data && ent->p == p && ent->base_offset == base_offset);
1815}
1816
1817static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1818        unsigned long *base_size, enum object_type *type, int keep_cache)
1819{
1820        void *ret;
1821        unsigned long hash = pack_entry_hash(p, base_offset);
1822        struct delta_base_cache_entry *ent = delta_base_cache + hash;
1823
1824        ret = ent->data;
1825        if (!ret || ent->p != p || ent->base_offset != base_offset)
1826                return unpack_entry(p, base_offset, type, base_size);
1827
1828        if (!keep_cache) {
1829                ent->data = NULL;
1830                ent->lru.next->prev = ent->lru.prev;
1831                ent->lru.prev->next = ent->lru.next;
1832                delta_base_cached -= ent->size;
1833        } else {
1834                ret = xmemdupz(ent->data, ent->size);
1835        }
1836        *type = ent->type;
1837        *base_size = ent->size;
1838        return ret;
1839}
1840
1841static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1842{
1843        if (ent->data) {
1844                free(ent->data);
1845                ent->data = NULL;
1846                ent->lru.next->prev = ent->lru.prev;
1847                ent->lru.prev->next = ent->lru.next;
1848                delta_base_cached -= ent->size;
1849        }
1850}
1851
1852void clear_delta_base_cache(void)
1853{
1854        unsigned long p;
1855        for (p = 0; p < MAX_DELTA_CACHE; p++)
1856                release_delta_base_cache(&delta_base_cache[p]);
1857}
1858
1859static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1860        void *base, unsigned long base_size, enum object_type type)
1861{
1862        unsigned long hash = pack_entry_hash(p, base_offset);
1863        struct delta_base_cache_entry *ent = delta_base_cache + hash;
1864        struct delta_base_cache_lru_list *lru;
1865
1866        release_delta_base_cache(ent);
1867        delta_base_cached += base_size;
1868
1869        for (lru = delta_base_cache_lru.next;
1870             delta_base_cached > delta_base_cache_limit
1871             && lru != &delta_base_cache_lru;
1872             lru = lru->next) {
1873                struct delta_base_cache_entry *f = (void *)lru;
1874                if (f->type == OBJ_BLOB)
1875                        release_delta_base_cache(f);
1876        }
1877        for (lru = delta_base_cache_lru.next;
1878             delta_base_cached > delta_base_cache_limit
1879             && lru != &delta_base_cache_lru;
1880             lru = lru->next) {
1881                struct delta_base_cache_entry *f = (void *)lru;
1882                release_delta_base_cache(f);
1883        }
1884
1885        ent->p = p;
1886        ent->base_offset = base_offset;
1887        ent->type = type;
1888        ent->data = base;
1889        ent->size = base_size;
1890        ent->lru.next = &delta_base_cache_lru;
1891        ent->lru.prev = delta_base_cache_lru.prev;
1892        delta_base_cache_lru.prev->next = &ent->lru;
1893        delta_base_cache_lru.prev = &ent->lru;
1894}
1895
1896static void *read_object(const unsigned char *sha1, enum object_type *type,
1897                         unsigned long *size);
1898
1899static void *unpack_delta_entry(struct packed_git *p,
1900                                struct pack_window **w_curs,
1901                                off_t curpos,
1902                                unsigned long delta_size,
1903                                off_t obj_offset,
1904                                enum object_type *type,
1905                                unsigned long *sizep)
1906{
1907        void *delta_data, *result, *base;
1908        unsigned long base_size;
1909        off_t base_offset;
1910
1911        base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
1912        if (!base_offset) {
1913                error("failed to validate delta base reference "
1914                      "at offset %"PRIuMAX" from %s",
1915                      (uintmax_t)curpos, p->pack_name);
1916                return NULL;
1917        }
1918        unuse_pack(w_curs);
1919        base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
1920        if (!base) {
1921                /*
1922                 * We're probably in deep shit, but let's try to fetch
1923                 * the required base anyway from another pack or loose.
1924                 * This is costly but should happen only in the presence
1925                 * of a corrupted pack, and is better than failing outright.
1926                 */
1927                struct revindex_entry *revidx;
1928                const unsigned char *base_sha1;
1929                revidx = find_pack_revindex(p, base_offset);
1930                if (!revidx)
1931                        return NULL;
1932                base_sha1 = nth_packed_object_sha1(p, revidx->nr);
1933                error("failed to read delta base object %s"
1934                      " at offset %"PRIuMAX" from %s",
1935                      sha1_to_hex(base_sha1), (uintmax_t)base_offset,
1936                      p->pack_name);
1937                mark_bad_packed_object(p, base_sha1);
1938                base = read_object(base_sha1, type, &base_size);
1939                if (!base)
1940                        return NULL;
1941        }
1942
1943        delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
1944        if (!delta_data) {
1945                error("failed to unpack compressed delta "
1946                      "at offset %"PRIuMAX" from %s",
1947                      (uintmax_t)curpos, p->pack_name);
1948                free(base);
1949                return NULL;
1950        }
1951        result = patch_delta(base, base_size,
1952                             delta_data, delta_size,
1953                             sizep);
1954        if (!result)
1955                die("failed to apply delta");
1956        free(delta_data);
1957        add_delta_base_cache(p, base_offset, base, base_size, *type);
1958        return result;
1959}
1960
1961static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1962{
1963        static FILE *log_file;
1964
1965        if (!log_file) {
1966                log_file = fopen(log_pack_access, "w");
1967                if (!log_file) {
1968                        error("cannot open pack access log '%s' for writing: %s",
1969                              log_pack_access, strerror(errno));
1970                        log_pack_access = NULL;
1971                        return;
1972                }
1973        }
1974        fprintf(log_file, "%s %"PRIuMAX"\n",
1975                p->pack_name, (uintmax_t)obj_offset);
1976        fflush(log_file);
1977}
1978
1979int do_check_packed_object_crc;
1980
1981void *unpack_entry(struct packed_git *p, off_t obj_offset,
1982                   enum object_type *type, unsigned long *sizep)
1983{
1984        struct pack_window *w_curs = NULL;
1985        off_t curpos = obj_offset;
1986        void *data;
1987
1988        if (log_pack_access)
1989                write_pack_access_log(p, obj_offset);
1990
1991        if (do_check_packed_object_crc && p->index_version > 1) {
1992                struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1993                unsigned long len = revidx[1].offset - obj_offset;
1994                if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1995                        const unsigned char *sha1 =
1996                                nth_packed_object_sha1(p, revidx->nr);
1997                        error("bad packed object CRC for %s",
1998                              sha1_to_hex(sha1));
1999                        mark_bad_packed_object(p, sha1);
2000                        unuse_pack(&w_curs);
2001                        return NULL;
2002                }
2003        }
2004
2005        *type = unpack_object_header(p, &w_curs, &curpos, sizep);
2006        switch (*type) {
2007        case OBJ_OFS_DELTA:
2008        case OBJ_REF_DELTA:
2009                data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
2010                                          obj_offset, type, sizep);
2011                break;
2012        case OBJ_COMMIT:
2013        case OBJ_TREE:
2014        case OBJ_BLOB:
2015        case OBJ_TAG:
2016                data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
2017                break;
2018        default:
2019                data = NULL;
2020                error("unknown object type %i at offset %"PRIuMAX" in %s",
2021                      *type, (uintmax_t)obj_offset, p->pack_name);
2022        }
2023        unuse_pack(&w_curs);
2024        return data;
2025}
2026
2027const unsigned char *nth_packed_object_sha1(struct packed_git *p,
2028                                            uint32_t n)
2029{
2030        const unsigned char *index = p->index_data;
2031        if (!index) {
2032                if (open_pack_index(p))
2033                        return NULL;
2034                index = p->index_data;
2035        }
2036        if (n >= p->num_objects)
2037                return NULL;
2038        index += 4 * 256;
2039        if (p->index_version == 1) {
2040                return index + 24 * n + 4;
2041        } else {
2042                index += 8;
2043                return index + 20 * n;
2044        }
2045}
2046
2047off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
2048{
2049        const unsigned char *index = p->index_data;
2050        index += 4 * 256;
2051        if (p->index_version == 1) {
2052                return ntohl(*((uint32_t *)(index + 24 * n)));
2053        } else {
2054                uint32_t off;
2055                index += 8 + p->num_objects * (20 + 4);
2056                off = ntohl(*((uint32_t *)(index + 4 * n)));
2057                if (!(off & 0x80000000))
2058                        return off;
2059                index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
2060                return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
2061                                   ntohl(*((uint32_t *)(index + 4)));
2062        }
2063}
2064
2065off_t find_pack_entry_one(const unsigned char *sha1,
2066                                  struct packed_git *p)
2067{
2068        const uint32_t *level1_ofs = p->index_data;
2069        const unsigned char *index = p->index_data;
2070        unsigned hi, lo, stride;
2071        static int use_lookup = -1;
2072        static int debug_lookup = -1;
2073
2074        if (debug_lookup < 0)
2075                debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
2076
2077        if (!index) {
2078                if (open_pack_index(p))
2079                        return 0;
2080                level1_ofs = p->index_data;
2081                index = p->index_data;
2082        }
2083        if (p->index_version > 1) {
2084                level1_ofs += 2;
2085                index += 8;
2086        }
2087        index += 4 * 256;
2088        hi = ntohl(level1_ofs[*sha1]);
2089        lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
2090        if (p->index_version > 1) {
2091                stride = 20;
2092        } else {
2093                stride = 24;
2094                index += 4;
2095        }
2096
2097        if (debug_lookup)
2098                printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
2099                       sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
2100
2101        if (use_lookup < 0)
2102                use_lookup = !!getenv("GIT_USE_LOOKUP");
2103        if (use_lookup) {
2104                int pos = sha1_entry_pos(index, stride, 0,
2105                                         lo, hi, p->num_objects, sha1);
2106                if (pos < 0)
2107                        return 0;
2108                return nth_packed_object_offset(p, pos);
2109        }
2110
2111        do {
2112                unsigned mi = (lo + hi) / 2;
2113                int cmp = hashcmp(index + mi * stride, sha1);
2114
2115                if (debug_lookup)
2116                        printf("lo %u hi %u rg %u mi %u\n",
2117                               lo, hi, hi - lo, mi);
2118                if (!cmp)
2119                        return nth_packed_object_offset(p, mi);
2120                if (cmp > 0)
2121                        hi = mi;
2122                else
2123                        lo = mi+1;
2124        } while (lo < hi);
2125        return 0;
2126}
2127
2128int is_pack_valid(struct packed_git *p)
2129{
2130        /* An already open pack is known to be valid. */
2131        if (p->pack_fd != -1)
2132                return 1;
2133
2134        /* If the pack has one window completely covering the
2135         * file size, the pack is known to be valid even if
2136         * the descriptor is not currently open.
2137         */
2138        if (p->windows) {
2139                struct pack_window *w = p->windows;
2140
2141                if (!w->offset && w->len == p->pack_size)
2142                        return 1;
2143        }
2144
2145        /* Force the pack to open to prove its valid. */
2146        return !open_packed_git(p);
2147}
2148
2149static int fill_pack_entry(const unsigned char *sha1,
2150                           struct pack_entry *e,
2151                           struct packed_git *p)
2152{
2153        off_t offset;
2154
2155        if (p->num_bad_objects) {
2156                unsigned i;
2157                for (i = 0; i < p->num_bad_objects; i++)
2158                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
2159                                return 0;
2160        }
2161
2162        offset = find_pack_entry_one(sha1, p);
2163        if (!offset)
2164                return 0;
2165
2166        /*
2167         * We are about to tell the caller where they can locate the
2168         * requested object.  We better make sure the packfile is
2169         * still here and can be accessed before supplying that
2170         * answer, as it may have been deleted since the index was
2171         * loaded!
2172         */
2173        if (!is_pack_valid(p)) {
2174                warning("packfile %s cannot be accessed", p->pack_name);
2175                return 0;
2176        }
2177        e->offset = offset;
2178        e->p = p;
2179        hashcpy(e->sha1, sha1);
2180        return 1;
2181}
2182
2183static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
2184{
2185        struct packed_git *p;
2186
2187        prepare_packed_git();
2188        if (!packed_git)
2189                return 0;
2190
2191        if (last_found_pack && fill_pack_entry(sha1, e, last_found_pack))
2192                return 1;
2193
2194        for (p = packed_git; p; p = p->next) {
2195                if (p == last_found_pack || !fill_pack_entry(sha1, e, p))
2196                        continue;
2197
2198                last_found_pack = p;
2199                return 1;
2200        }
2201        return 0;
2202}
2203
2204struct packed_git *find_sha1_pack(const unsigned char *sha1,
2205                                  struct packed_git *packs)
2206{
2207        struct packed_git *p;
2208
2209        for (p = packs; p; p = p->next) {
2210                if (find_pack_entry_one(sha1, p))
2211                        return p;
2212        }
2213        return NULL;
2214
2215}
2216
2217static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
2218{
2219        int status;
2220        unsigned long mapsize, size;
2221        void *map;
2222        git_zstream stream;
2223        char hdr[32];
2224
2225        map = map_sha1_file(sha1, &mapsize);
2226        if (!map)
2227                return error("unable to find %s", sha1_to_hex(sha1));
2228        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2229                status = error("unable to unpack %s header",
2230                               sha1_to_hex(sha1));
2231        else if ((status = parse_sha1_header(hdr, &size)) < 0)
2232                status = error("unable to parse %s header", sha1_to_hex(sha1));
2233        else if (sizep)
2234                *sizep = size;
2235        git_inflate_end(&stream);
2236        munmap(map, mapsize);
2237        return status;
2238}
2239
2240/* returns enum object_type or negative */
2241int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi)
2242{
2243        struct cached_object *co;
2244        struct pack_entry e;
2245        int status, rtype;
2246
2247        co = find_cached_object(sha1);
2248        if (co) {
2249                if (oi->sizep)
2250                        *(oi->sizep) = co->size;
2251                oi->whence = OI_CACHED;
2252                return co->type;
2253        }
2254
2255        if (!find_pack_entry(sha1, &e)) {
2256                /* Most likely it's a loose object. */
2257                status = sha1_loose_object_info(sha1, oi->sizep);
2258                if (status >= 0) {
2259                        oi->whence = OI_LOOSE;
2260                        return status;
2261                }
2262
2263                /* Not a loose object; someone else may have just packed it. */
2264                reprepare_packed_git();
2265                if (!find_pack_entry(sha1, &e))
2266                        return status;
2267        }
2268
2269        status = packed_object_info(e.p, e.offset, oi->sizep, &rtype);
2270        if (status < 0) {
2271                mark_bad_packed_object(e.p, sha1);
2272                status = sha1_object_info_extended(sha1, oi);
2273        } else if (in_delta_base_cache(e.p, e.offset)) {
2274                oi->whence = OI_DBCACHED;
2275        } else {
2276                oi->whence = OI_PACKED;
2277                oi->u.packed.offset = e.offset;
2278                oi->u.packed.pack = e.p;
2279                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
2280                                         rtype == OBJ_OFS_DELTA);
2281        }
2282
2283        return status;
2284}
2285
2286int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2287{
2288        struct object_info oi;
2289
2290        oi.sizep = sizep;
2291        return sha1_object_info_extended(sha1, &oi);
2292}
2293
2294static void *read_packed_sha1(const unsigned char *sha1,
2295                              enum object_type *type, unsigned long *size)
2296{
2297        struct pack_entry e;
2298        void *data;
2299
2300        if (!find_pack_entry(sha1, &e))
2301                return NULL;
2302        data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
2303        if (!data) {
2304                /*
2305                 * We're probably in deep shit, but let's try to fetch
2306                 * the required object anyway from another pack or loose.
2307                 * This should happen only in the presence of a corrupted
2308                 * pack, and is better than failing outright.
2309                 */
2310                error("failed to read object %s at offset %"PRIuMAX" from %s",
2311                      sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2312                mark_bad_packed_object(e.p, sha1);
2313                data = read_object(sha1, type, size);
2314        }
2315        return data;
2316}
2317
2318int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2319                      unsigned char *sha1)
2320{
2321        struct cached_object *co;
2322
2323        hash_sha1_file(buf, len, typename(type), sha1);
2324        if (has_sha1_file(sha1) || find_cached_object(sha1))
2325                return 0;
2326        if (cached_object_alloc <= cached_object_nr) {
2327                cached_object_alloc = alloc_nr(cached_object_alloc);
2328                cached_objects = xrealloc(cached_objects,
2329                                          sizeof(*cached_objects) *
2330                                          cached_object_alloc);
2331        }
2332        co = &cached_objects[cached_object_nr++];
2333        co->size = len;
2334        co->type = type;
2335        co->buf = xmalloc(len);
2336        memcpy(co->buf, buf, len);
2337        hashcpy(co->sha1, sha1);
2338        return 0;
2339}
2340
2341static void *read_object(const unsigned char *sha1, enum object_type *type,
2342                         unsigned long *size)
2343{
2344        unsigned long mapsize;
2345        void *map, *buf;
2346        struct cached_object *co;
2347
2348        co = find_cached_object(sha1);
2349        if (co) {
2350                *type = co->type;
2351                *size = co->size;
2352                return xmemdupz(co->buf, co->size);
2353        }
2354
2355        buf = read_packed_sha1(sha1, type, size);
2356        if (buf)
2357                return buf;
2358        map = map_sha1_file(sha1, &mapsize);
2359        if (map) {
2360                buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2361                munmap(map, mapsize);
2362                return buf;
2363        }
2364        reprepare_packed_git();
2365        return read_packed_sha1(sha1, type, size);
2366}
2367
2368/*
2369 * This function dies on corrupt objects; the callers who want to
2370 * deal with them should arrange to call read_object() and give error
2371 * messages themselves.
2372 */
2373void *read_sha1_file_extended(const unsigned char *sha1,
2374                              enum object_type *type,
2375                              unsigned long *size,
2376                              unsigned flag)
2377{
2378        void *data;
2379        char *path;
2380        const struct packed_git *p;
2381        const unsigned char *repl = (flag & READ_SHA1_FILE_REPLACE)
2382                ? lookup_replace_object(sha1) : sha1;
2383
2384        errno = 0;
2385        data = read_object(repl, type, size);
2386        if (data)
2387                return data;
2388
2389        if (errno && errno != ENOENT)
2390                die_errno("failed to read object %s", sha1_to_hex(sha1));
2391
2392        /* die if we replaced an object with one that does not exist */
2393        if (repl != sha1)
2394                die("replacement %s not found for %s",
2395                    sha1_to_hex(repl), sha1_to_hex(sha1));
2396
2397        if (has_loose_object(repl)) {
2398                path = sha1_file_name(sha1);
2399                die("loose object %s (stored in %s) is corrupt",
2400                    sha1_to_hex(repl), path);
2401        }
2402
2403        if ((p = has_packed_and_bad(repl)) != NULL)
2404                die("packed object %s (stored in %s) is corrupt",
2405                    sha1_to_hex(repl), p->pack_name);
2406
2407        return NULL;
2408}
2409
2410void *read_object_with_reference(const unsigned char *sha1,
2411                                 const char *required_type_name,
2412                                 unsigned long *size,
2413                                 unsigned char *actual_sha1_return)
2414{
2415        enum object_type type, required_type;
2416        void *buffer;
2417        unsigned long isize;
2418        unsigned char actual_sha1[20];
2419
2420        required_type = type_from_string(required_type_name);
2421        hashcpy(actual_sha1, sha1);
2422        while (1) {
2423                int ref_length = -1;
2424                const char *ref_type = NULL;
2425
2426                buffer = read_sha1_file(actual_sha1, &type, &isize);
2427                if (!buffer)
2428                        return NULL;
2429                if (type == required_type) {
2430                        *size = isize;
2431                        if (actual_sha1_return)
2432                                hashcpy(actual_sha1_return, actual_sha1);
2433                        return buffer;
2434                }
2435                /* Handle references */
2436                else if (type == OBJ_COMMIT)
2437                        ref_type = "tree ";
2438                else if (type == OBJ_TAG)
2439                        ref_type = "object ";
2440                else {
2441                        free(buffer);
2442                        return NULL;
2443                }
2444                ref_length = strlen(ref_type);
2445
2446                if (ref_length + 40 > isize ||
2447                    memcmp(buffer, ref_type, ref_length) ||
2448                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2449                        free(buffer);
2450                        return NULL;
2451                }
2452                free(buffer);
2453                /* Now we have the ID of the referred-to object in
2454                 * actual_sha1.  Check again. */
2455        }
2456}
2457
2458static void write_sha1_file_prepare(const void *buf, unsigned long len,
2459                                    const char *type, unsigned char *sha1,
2460                                    char *hdr, int *hdrlen)
2461{
2462        git_SHA_CTX c;
2463
2464        /* Generate the header */
2465        *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
2466
2467        /* Sha1.. */
2468        git_SHA1_Init(&c);
2469        git_SHA1_Update(&c, hdr, *hdrlen);
2470        git_SHA1_Update(&c, buf, len);
2471        git_SHA1_Final(sha1, &c);
2472}
2473
2474/*
2475 * Move the just written object into its final resting place.
2476 * NEEDSWORK: this should be renamed to finalize_temp_file() as
2477 * "moving" is only a part of what it does, when no patch between
2478 * master to pu changes the call sites of this function.
2479 */
2480int move_temp_to_file(const char *tmpfile, const char *filename)
2481{
2482        int ret = 0;
2483
2484        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2485                goto try_rename;
2486        else if (link(tmpfile, filename))
2487                ret = errno;
2488
2489        /*
2490         * Coda hack - coda doesn't like cross-directory links,
2491         * so we fall back to a rename, which will mean that it
2492         * won't be able to check collisions, but that's not a
2493         * big deal.
2494         *
2495         * The same holds for FAT formatted media.
2496         *
2497         * When this succeeds, we just return.  We have nothing
2498         * left to unlink.
2499         */
2500        if (ret && ret != EEXIST) {
2501        try_rename:
2502                if (!rename(tmpfile, filename))
2503                        goto out;
2504                ret = errno;
2505        }
2506        unlink_or_warn(tmpfile);
2507        if (ret) {
2508                if (ret != EEXIST) {
2509                        return error("unable to write sha1 filename %s: %s", filename, strerror(ret));
2510                }
2511                /* FIXME!!! Collision check here ? */
2512        }
2513
2514out:
2515        if (adjust_shared_perm(filename))
2516                return error("unable to set permission to '%s'", filename);
2517        return 0;
2518}
2519
2520static int write_buffer(int fd, const void *buf, size_t len)
2521{
2522        if (write_in_full(fd, buf, len) < 0)
2523                return error("file write error (%s)", strerror(errno));
2524        return 0;
2525}
2526
2527int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2528                   unsigned char *sha1)
2529{
2530        char hdr[32];
2531        int hdrlen;
2532        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2533        return 0;
2534}
2535
2536/* Finalize a file on disk, and close it. */
2537static void close_sha1_file(int fd)
2538{
2539        if (fsync_object_files)
2540                fsync_or_die(fd, "sha1 file");
2541        if (close(fd) != 0)
2542                die_errno("error when closing sha1 file");
2543}
2544
2545/* Size of directory component, including the ending '/' */
2546static inline int directory_size(const char *filename)
2547{
2548        const char *s = strrchr(filename, '/');
2549        if (!s)
2550                return 0;
2551        return s - filename + 1;
2552}
2553
2554/*
2555 * This creates a temporary file in the same directory as the final
2556 * 'filename'
2557 *
2558 * We want to avoid cross-directory filename renames, because those
2559 * can have problems on various filesystems (FAT, NFS, Coda).
2560 */
2561static int create_tmpfile(char *buffer, size_t bufsiz, const char *filename)
2562{
2563        int fd, dirlen = directory_size(filename);
2564
2565        if (dirlen + 20 > bufsiz) {
2566                errno = ENAMETOOLONG;
2567                return -1;
2568        }
2569        memcpy(buffer, filename, dirlen);
2570        strcpy(buffer + dirlen, "tmp_obj_XXXXXX");
2571        fd = git_mkstemp_mode(buffer, 0444);
2572        if (fd < 0 && dirlen && errno == ENOENT) {
2573                /* Make sure the directory exists */
2574                memcpy(buffer, filename, dirlen);
2575                buffer[dirlen-1] = 0;
2576                if (mkdir(buffer, 0777) || adjust_shared_perm(buffer))
2577                        return -1;
2578
2579                /* Try again */
2580                strcpy(buffer + dirlen - 1, "/tmp_obj_XXXXXX");
2581                fd = git_mkstemp_mode(buffer, 0444);
2582        }
2583        return fd;
2584}
2585
2586static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
2587                              const void *buf, unsigned long len, time_t mtime)
2588{
2589        int fd, ret;
2590        unsigned char compressed[4096];
2591        git_zstream stream;
2592        git_SHA_CTX c;
2593        unsigned char parano_sha1[20];
2594        char *filename;
2595        static char tmp_file[PATH_MAX];
2596
2597        filename = sha1_file_name(sha1);
2598        fd = create_tmpfile(tmp_file, sizeof(tmp_file), filename);
2599        if (fd < 0) {
2600                if (errno == EACCES)
2601                        return error("insufficient permission for adding an object to repository database %s", get_object_directory());
2602                else
2603                        return error("unable to create temporary file: %s", strerror(errno));
2604        }
2605
2606        /* Set it up */
2607        memset(&stream, 0, sizeof(stream));
2608        git_deflate_init(&stream, zlib_compression_level);
2609        stream.next_out = compressed;
2610        stream.avail_out = sizeof(compressed);
2611        git_SHA1_Init(&c);
2612
2613        /* First header.. */
2614        stream.next_in = (unsigned char *)hdr;
2615        stream.avail_in = hdrlen;
2616        while (git_deflate(&stream, 0) == Z_OK)
2617                ; /* nothing */
2618        git_SHA1_Update(&c, hdr, hdrlen);
2619
2620        /* Then the data itself.. */
2621        stream.next_in = (void *)buf;
2622        stream.avail_in = len;
2623        do {
2624                unsigned char *in0 = stream.next_in;
2625                ret = git_deflate(&stream, Z_FINISH);
2626                git_SHA1_Update(&c, in0, stream.next_in - in0);
2627                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
2628                        die("unable to write sha1 file");
2629                stream.next_out = compressed;
2630                stream.avail_out = sizeof(compressed);
2631        } while (ret == Z_OK);
2632
2633        if (ret != Z_STREAM_END)
2634                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
2635        ret = git_deflate_end_gently(&stream);
2636        if (ret != Z_OK)
2637                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
2638        git_SHA1_Final(parano_sha1, &c);
2639        if (hashcmp(sha1, parano_sha1) != 0)
2640                die("confused by unstable object source data for %s", sha1_to_hex(sha1));
2641
2642        close_sha1_file(fd);
2643
2644        if (mtime) {
2645                struct utimbuf utb;
2646                utb.actime = mtime;
2647                utb.modtime = mtime;
2648                if (utime(tmp_file, &utb) < 0)
2649                        warning("failed utime() on %s: %s",
2650                                tmp_file, strerror(errno));
2651        }
2652
2653        return move_temp_to_file(tmp_file, filename);
2654}
2655
2656int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
2657{
2658        unsigned char sha1[20];
2659        char hdr[32];
2660        int hdrlen;
2661
2662        /* Normally if we have it in the pack then we do not bother writing
2663         * it out into .git/objects/??/?{38} file.
2664         */
2665        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2666        if (returnsha1)
2667                hashcpy(returnsha1, sha1);
2668        if (has_sha1_file(sha1))
2669                return 0;
2670        return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
2671}
2672
2673int force_object_loose(const unsigned char *sha1, time_t mtime)
2674{
2675        void *buf;
2676        unsigned long len;
2677        enum object_type type;
2678        char hdr[32];
2679        int hdrlen;
2680        int ret;
2681
2682        if (has_loose_object(sha1))
2683                return 0;
2684        buf = read_packed_sha1(sha1, &type, &len);
2685        if (!buf)
2686                return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
2687        hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
2688        ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
2689        free(buf);
2690
2691        return ret;
2692}
2693
2694int has_pack_index(const unsigned char *sha1)
2695{
2696        struct stat st;
2697        if (stat(sha1_pack_index_name(sha1), &st))
2698                return 0;
2699        return 1;
2700}
2701
2702int has_sha1_pack(const unsigned char *sha1)
2703{
2704        struct pack_entry e;
2705        return find_pack_entry(sha1, &e);
2706}
2707
2708int has_sha1_file(const unsigned char *sha1)
2709{
2710        struct pack_entry e;
2711
2712        if (find_pack_entry(sha1, &e))
2713                return 1;
2714        return has_loose_object(sha1);
2715}
2716
2717static void check_tree(const void *buf, size_t size)
2718{
2719        struct tree_desc desc;
2720        struct name_entry entry;
2721
2722        init_tree_desc(&desc, buf, size);
2723        while (tree_entry(&desc, &entry))
2724                /* do nothing
2725                 * tree_entry() will die() on malformed entries */
2726                ;
2727}
2728
2729static void check_commit(const void *buf, size_t size)
2730{
2731        struct commit c;
2732        memset(&c, 0, sizeof(c));
2733        if (parse_commit_buffer(&c, buf, size))
2734                die("corrupt commit");
2735}
2736
2737static void check_tag(const void *buf, size_t size)
2738{
2739        struct tag t;
2740        memset(&t, 0, sizeof(t));
2741        if (parse_tag_buffer(&t, buf, size))
2742                die("corrupt tag");
2743}
2744
2745static int index_mem(unsigned char *sha1, void *buf, size_t size,
2746                     enum object_type type,
2747                     const char *path, unsigned flags)
2748{
2749        int ret, re_allocated = 0;
2750        int write_object = flags & HASH_WRITE_OBJECT;
2751
2752        if (!type)
2753                type = OBJ_BLOB;
2754
2755        /*
2756         * Convert blobs to git internal format
2757         */
2758        if ((type == OBJ_BLOB) && path) {
2759                struct strbuf nbuf = STRBUF_INIT;
2760                if (convert_to_git(path, buf, size, &nbuf,
2761                                   write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
2762                        buf = strbuf_detach(&nbuf, &size);
2763                        re_allocated = 1;
2764                }
2765        }
2766        if (flags & HASH_FORMAT_CHECK) {
2767                if (type == OBJ_TREE)
2768                        check_tree(buf, size);
2769                if (type == OBJ_COMMIT)
2770                        check_commit(buf, size);
2771                if (type == OBJ_TAG)
2772                        check_tag(buf, size);
2773        }
2774
2775        if (write_object)
2776                ret = write_sha1_file(buf, size, typename(type), sha1);
2777        else
2778                ret = hash_sha1_file(buf, size, typename(type), sha1);
2779        if (re_allocated)
2780                free(buf);
2781        return ret;
2782}
2783
2784static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
2785                      const char *path, unsigned flags)
2786{
2787        struct strbuf sbuf = STRBUF_INIT;
2788        int ret;
2789
2790        if (strbuf_read(&sbuf, fd, 4096) >= 0)
2791                ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
2792        else
2793                ret = -1;
2794        strbuf_release(&sbuf);
2795        return ret;
2796}
2797
2798#define SMALL_FILE_SIZE (32*1024)
2799
2800static int index_core(unsigned char *sha1, int fd, size_t size,
2801                      enum object_type type, const char *path,
2802                      unsigned flags)
2803{
2804        int ret;
2805
2806        if (!size) {
2807                ret = index_mem(sha1, NULL, size, type, path, flags);
2808        } else if (size <= SMALL_FILE_SIZE) {
2809                char *buf = xmalloc(size);
2810                if (size == read_in_full(fd, buf, size))
2811                        ret = index_mem(sha1, buf, size, type, path, flags);
2812                else
2813                        ret = error("short read %s", strerror(errno));
2814                free(buf);
2815        } else {
2816                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2817                ret = index_mem(sha1, buf, size, type, path, flags);
2818                munmap(buf, size);
2819        }
2820        return ret;
2821}
2822
2823/*
2824 * This creates one packfile per large blob unless bulk-checkin
2825 * machinery is "plugged".
2826 *
2827 * This also bypasses the usual "convert-to-git" dance, and that is on
2828 * purpose. We could write a streaming version of the converting
2829 * functions and insert that before feeding the data to fast-import
2830 * (or equivalent in-core API described above). However, that is
2831 * somewhat complicated, as we do not know the size of the filter
2832 * result, which we need to know beforehand when writing a git object.
2833 * Since the primary motivation for trying to stream from the working
2834 * tree file and to avoid mmaping it in core is to deal with large
2835 * binary blobs, they generally do not want to get any conversion, and
2836 * callers should avoid this code path when filters are requested.
2837 */
2838static int index_stream(unsigned char *sha1, int fd, size_t size,
2839                        enum object_type type, const char *path,
2840                        unsigned flags)
2841{
2842        return index_bulk_checkin(sha1, fd, size, type, path, flags);
2843}
2844
2845int index_fd(unsigned char *sha1, int fd, struct stat *st,
2846             enum object_type type, const char *path, unsigned flags)
2847{
2848        int ret;
2849        size_t size = xsize_t(st->st_size);
2850
2851        if (!S_ISREG(st->st_mode))
2852                ret = index_pipe(sha1, fd, type, path, flags);
2853        else if (size <= big_file_threshold || type != OBJ_BLOB ||
2854                 (path && would_convert_to_git(path, NULL, 0, 0)))
2855                ret = index_core(sha1, fd, size, type, path, flags);
2856        else
2857                ret = index_stream(sha1, fd, size, type, path, flags);
2858        close(fd);
2859        return ret;
2860}
2861
2862int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
2863{
2864        int fd;
2865        struct strbuf sb = STRBUF_INIT;
2866
2867        switch (st->st_mode & S_IFMT) {
2868        case S_IFREG:
2869                fd = open(path, O_RDONLY);
2870                if (fd < 0)
2871                        return error("open(\"%s\"): %s", path,
2872                                     strerror(errno));
2873                if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
2874                        return error("%s: failed to insert into database",
2875                                     path);
2876                break;
2877        case S_IFLNK:
2878                if (strbuf_readlink(&sb, path, st->st_size)) {
2879                        char *errstr = strerror(errno);
2880                        return error("readlink(\"%s\"): %s", path,
2881                                     errstr);
2882                }
2883                if (!(flags & HASH_WRITE_OBJECT))
2884                        hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
2885                else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
2886                        return error("%s: failed to insert into database",
2887                                     path);
2888                strbuf_release(&sb);
2889                break;
2890        case S_IFDIR:
2891                return resolve_gitlink_ref(path, "HEAD", sha1);
2892        default:
2893                return error("%s: unsupported file type", path);
2894        }
2895        return 0;
2896}
2897
2898int read_pack_header(int fd, struct pack_header *header)
2899{
2900        if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
2901                /* "eof before pack header was fully read" */
2902                return PH_ERROR_EOF;
2903
2904        if (header->hdr_signature != htonl(PACK_SIGNATURE))
2905                /* "protocol error (pack signature mismatch detected)" */
2906                return PH_ERROR_PACK_SIGNATURE;
2907        if (!pack_version_ok(header->hdr_version))
2908                /* "protocol error (pack version unsupported)" */
2909                return PH_ERROR_PROTOCOL;
2910        return 0;
2911}
2912
2913void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
2914{
2915        enum object_type type = sha1_object_info(sha1, NULL);
2916        if (type < 0)
2917                die("%s is not a valid object", sha1_to_hex(sha1));
2918        if (type != expect)
2919                die("%s is not a valid '%s' object", sha1_to_hex(sha1),
2920                    typename(expect));
2921}