sha1_file.con commit Fix various memory leaks in http-push.c and http-walker.c (3a462bc)
   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 "delta.h"
  11#include "pack.h"
  12#include "blob.h"
  13#include "commit.h"
  14#include "tag.h"
  15#include "tree.h"
  16#include "refs.h"
  17
  18#ifndef O_NOATIME
  19#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  20#define O_NOATIME 01000000
  21#else
  22#define O_NOATIME 0
  23#endif
  24#endif
  25
  26#ifdef NO_C99_FORMAT
  27#define SZ_FMT "lu"
  28static unsigned long sz_fmt(size_t s) { return (unsigned long)s; }
  29#else
  30#define SZ_FMT "zu"
  31static size_t sz_fmt(size_t s) { return s; }
  32#endif
  33
  34const unsigned char null_sha1[20];
  35
  36static unsigned int sha1_file_open_flag = O_NOATIME;
  37
  38const signed char hexval_table[256] = {
  39         -1, -1, -1, -1, -1, -1, -1, -1,                /* 00-07 */
  40         -1, -1, -1, -1, -1, -1, -1, -1,                /* 08-0f */
  41         -1, -1, -1, -1, -1, -1, -1, -1,                /* 10-17 */
  42         -1, -1, -1, -1, -1, -1, -1, -1,                /* 18-1f */
  43         -1, -1, -1, -1, -1, -1, -1, -1,                /* 20-27 */
  44         -1, -1, -1, -1, -1, -1, -1, -1,                /* 28-2f */
  45          0,  1,  2,  3,  4,  5,  6,  7,                /* 30-37 */
  46          8,  9, -1, -1, -1, -1, -1, -1,                /* 38-3f */
  47         -1, 10, 11, 12, 13, 14, 15, -1,                /* 40-47 */
  48         -1, -1, -1, -1, -1, -1, -1, -1,                /* 48-4f */
  49         -1, -1, -1, -1, -1, -1, -1, -1,                /* 50-57 */
  50         -1, -1, -1, -1, -1, -1, -1, -1,                /* 58-5f */
  51         -1, 10, 11, 12, 13, 14, 15, -1,                /* 60-67 */
  52         -1, -1, -1, -1, -1, -1, -1, -1,                /* 68-67 */
  53         -1, -1, -1, -1, -1, -1, -1, -1,                /* 70-77 */
  54         -1, -1, -1, -1, -1, -1, -1, -1,                /* 78-7f */
  55         -1, -1, -1, -1, -1, -1, -1, -1,                /* 80-87 */
  56         -1, -1, -1, -1, -1, -1, -1, -1,                /* 88-8f */
  57         -1, -1, -1, -1, -1, -1, -1, -1,                /* 90-97 */
  58         -1, -1, -1, -1, -1, -1, -1, -1,                /* 98-9f */
  59         -1, -1, -1, -1, -1, -1, -1, -1,                /* a0-a7 */
  60         -1, -1, -1, -1, -1, -1, -1, -1,                /* a8-af */
  61         -1, -1, -1, -1, -1, -1, -1, -1,                /* b0-b7 */
  62         -1, -1, -1, -1, -1, -1, -1, -1,                /* b8-bf */
  63         -1, -1, -1, -1, -1, -1, -1, -1,                /* c0-c7 */
  64         -1, -1, -1, -1, -1, -1, -1, -1,                /* c8-cf */
  65         -1, -1, -1, -1, -1, -1, -1, -1,                /* d0-d7 */
  66         -1, -1, -1, -1, -1, -1, -1, -1,                /* d8-df */
  67         -1, -1, -1, -1, -1, -1, -1, -1,                /* e0-e7 */
  68         -1, -1, -1, -1, -1, -1, -1, -1,                /* e8-ef */
  69         -1, -1, -1, -1, -1, -1, -1, -1,                /* f0-f7 */
  70         -1, -1, -1, -1, -1, -1, -1, -1,                /* f8-ff */
  71};
  72
  73int get_sha1_hex(const char *hex, unsigned char *sha1)
  74{
  75        int i;
  76        for (i = 0; i < 20; i++) {
  77                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  78                if (val & ~0xff)
  79                        return -1;
  80                *sha1++ = val;
  81                hex += 2;
  82        }
  83        return 0;
  84}
  85
  86int safe_create_leading_directories(char *path)
  87{
  88        char *pos = path;
  89        struct stat st;
  90
  91        if (is_absolute_path(path))
  92                pos++;
  93
  94        while (pos) {
  95                pos = strchr(pos, '/');
  96                if (!pos)
  97                        break;
  98                *pos = 0;
  99                if (!stat(path, &st)) {
 100                        /* path exists */
 101                        if (!S_ISDIR(st.st_mode)) {
 102                                *pos = '/';
 103                                return -3;
 104                        }
 105                }
 106                else if (mkdir(path, 0777)) {
 107                        *pos = '/';
 108                        return -1;
 109                }
 110                else if (adjust_shared_perm(path)) {
 111                        *pos = '/';
 112                        return -2;
 113                }
 114                *pos++ = '/';
 115        }
 116        return 0;
 117}
 118
 119char * sha1_to_hex(const unsigned char *sha1)
 120{
 121        static int bufno;
 122        static char hexbuffer[4][50];
 123        static const char hex[] = "0123456789abcdef";
 124        char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
 125        int i;
 126
 127        for (i = 0; i < 20; i++) {
 128                unsigned int val = *sha1++;
 129                *buf++ = hex[val >> 4];
 130                *buf++ = hex[val & 0xf];
 131        }
 132        *buf = '\0';
 133
 134        return buffer;
 135}
 136
 137static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 138{
 139        int i;
 140        for (i = 0; i < 20; i++) {
 141                static char hex[] = "0123456789abcdef";
 142                unsigned int val = sha1[i];
 143                char *pos = pathbuf + i*2 + (i > 0);
 144                *pos++ = hex[val >> 4];
 145                *pos = hex[val & 0xf];
 146        }
 147}
 148
 149/*
 150 * NOTE! This returns a statically allocated buffer, so you have to be
 151 * careful about using it. Do a "xstrdup()" if you need to save the
 152 * filename.
 153 *
 154 * Also note that this returns the location for creating.  Reading
 155 * SHA1 file can happen from any alternate directory listed in the
 156 * DB_ENVIRONMENT environment variable if it is not found in
 157 * the primary object database.
 158 */
 159char *sha1_file_name(const unsigned char *sha1)
 160{
 161        static char *name, *base;
 162
 163        if (!base) {
 164                const char *sha1_file_directory = get_object_directory();
 165                int len = strlen(sha1_file_directory);
 166                base = xmalloc(len + 60);
 167                memcpy(base, sha1_file_directory, len);
 168                memset(base+len, 0, 60);
 169                base[len] = '/';
 170                base[len+3] = '/';
 171                name = base + len + 1;
 172        }
 173        fill_sha1_path(name, sha1);
 174        return base;
 175}
 176
 177char *sha1_pack_name(const unsigned char *sha1)
 178{
 179        static const char hex[] = "0123456789abcdef";
 180        static char *name, *base, *buf;
 181        int i;
 182
 183        if (!base) {
 184                const char *sha1_file_directory = get_object_directory();
 185                int len = strlen(sha1_file_directory);
 186                base = xmalloc(len + 60);
 187                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 188                name = base + len + 11;
 189        }
 190
 191        buf = name;
 192
 193        for (i = 0; i < 20; i++) {
 194                unsigned int val = *sha1++;
 195                *buf++ = hex[val >> 4];
 196                *buf++ = hex[val & 0xf];
 197        }
 198
 199        return base;
 200}
 201
 202char *sha1_pack_index_name(const unsigned char *sha1)
 203{
 204        static const char hex[] = "0123456789abcdef";
 205        static char *name, *base, *buf;
 206        int i;
 207
 208        if (!base) {
 209                const char *sha1_file_directory = get_object_directory();
 210                int len = strlen(sha1_file_directory);
 211                base = xmalloc(len + 60);
 212                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 213                name = base + len + 11;
 214        }
 215
 216        buf = name;
 217
 218        for (i = 0; i < 20; i++) {
 219                unsigned int val = *sha1++;
 220                *buf++ = hex[val >> 4];
 221                *buf++ = hex[val & 0xf];
 222        }
 223
 224        return base;
 225}
 226
 227struct alternate_object_database *alt_odb_list;
 228static struct alternate_object_database **alt_odb_tail;
 229
 230static void read_info_alternates(const char * alternates, int depth);
 231
 232/*
 233 * Prepare alternate object database registry.
 234 *
 235 * The variable alt_odb_list points at the list of struct
 236 * alternate_object_database.  The elements on this list come from
 237 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 238 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 239 * whose contents is similar to that environment variable but can be
 240 * LF separated.  Its base points at a statically allocated buffer that
 241 * contains "/the/directory/corresponding/to/.git/objects/...", while
 242 * its name points just after the slash at the end of ".git/objects/"
 243 * in the example above, and has enough space to hold 40-byte hex
 244 * SHA1, an extra slash for the first level indirection, and the
 245 * terminating NUL.
 246 */
 247static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 248{
 249        struct stat st;
 250        const char *objdir = get_object_directory();
 251        struct alternate_object_database *ent;
 252        struct alternate_object_database *alt;
 253        /* 43 = 40-byte + 2 '/' + terminating NUL */
 254        int pfxlen = len;
 255        int entlen = pfxlen + 43;
 256        int base_len = -1;
 257
 258        if (!is_absolute_path(entry) && relative_base) {
 259                /* Relative alt-odb */
 260                if (base_len < 0)
 261                        base_len = strlen(relative_base) + 1;
 262                entlen += base_len;
 263                pfxlen += base_len;
 264        }
 265        ent = xmalloc(sizeof(*ent) + entlen);
 266
 267        if (!is_absolute_path(entry) && relative_base) {
 268                memcpy(ent->base, relative_base, base_len - 1);
 269                ent->base[base_len - 1] = '/';
 270                memcpy(ent->base + base_len, entry, len);
 271        }
 272        else
 273                memcpy(ent->base, entry, pfxlen);
 274
 275        ent->name = ent->base + pfxlen + 1;
 276        ent->base[pfxlen + 3] = '/';
 277        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 278
 279        /* Detect cases where alternate disappeared */
 280        if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 281                error("object directory %s does not exist; "
 282                      "check .git/objects/info/alternates.",
 283                      ent->base);
 284                free(ent);
 285                return -1;
 286        }
 287
 288        /* Prevent the common mistake of listing the same
 289         * thing twice, or object directory itself.
 290         */
 291        for (alt = alt_odb_list; alt; alt = alt->next) {
 292                if (!memcmp(ent->base, alt->base, pfxlen)) {
 293                        free(ent);
 294                        return -1;
 295                }
 296        }
 297        if (!memcmp(ent->base, objdir, pfxlen)) {
 298                free(ent);
 299                return -1;
 300        }
 301
 302        /* add the alternate entry */
 303        *alt_odb_tail = ent;
 304        alt_odb_tail = &(ent->next);
 305        ent->next = NULL;
 306
 307        /* recursively add alternates */
 308        read_info_alternates(ent->base, depth + 1);
 309
 310        ent->base[pfxlen] = '/';
 311
 312        return 0;
 313}
 314
 315static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 316                                 const char *relative_base, int depth)
 317{
 318        const char *cp, *last;
 319
 320        if (depth > 5) {
 321                error("%s: ignoring alternate object stores, nesting too deep.",
 322                                relative_base);
 323                return;
 324        }
 325
 326        last = alt;
 327        while (last < ep) {
 328                cp = last;
 329                if (cp < ep && *cp == '#') {
 330                        while (cp < ep && *cp != sep)
 331                                cp++;
 332                        last = cp + 1;
 333                        continue;
 334                }
 335                while (cp < ep && *cp != sep)
 336                        cp++;
 337                if (last != cp) {
 338                        if (!is_absolute_path(last) && depth) {
 339                                error("%s: ignoring relative alternate object store %s",
 340                                                relative_base, last);
 341                        } else {
 342                                link_alt_odb_entry(last, cp - last,
 343                                                relative_base, depth);
 344                        }
 345                }
 346                while (cp < ep && *cp == sep)
 347                        cp++;
 348                last = cp;
 349        }
 350}
 351
 352static void read_info_alternates(const char * relative_base, int depth)
 353{
 354        char *map;
 355        size_t mapsz;
 356        struct stat st;
 357        const char alt_file_name[] = "info/alternates";
 358        /* Given that relative_base is no longer than PATH_MAX,
 359           ensure that "path" has enough space to append "/", the
 360           file name, "info/alternates", and a trailing NUL.  */
 361        char path[PATH_MAX + 1 + sizeof alt_file_name];
 362        int fd;
 363
 364        sprintf(path, "%s/%s", relative_base, alt_file_name);
 365        fd = open(path, O_RDONLY);
 366        if (fd < 0)
 367                return;
 368        if (fstat(fd, &st) || (st.st_size == 0)) {
 369                close(fd);
 370                return;
 371        }
 372        mapsz = xsize_t(st.st_size);
 373        map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
 374        close(fd);
 375
 376        link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth);
 377
 378        munmap(map, mapsz);
 379}
 380
 381void prepare_alt_odb(void)
 382{
 383        const char *alt;
 384
 385        if (alt_odb_tail)
 386                return;
 387
 388        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 389        if (!alt) alt = "";
 390
 391        alt_odb_tail = &alt_odb_list;
 392        link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 393
 394        read_info_alternates(get_object_directory(), 0);
 395}
 396
 397static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 398{
 399        char *name = sha1_file_name(sha1);
 400        struct alternate_object_database *alt;
 401
 402        if (!stat(name, st))
 403                return name;
 404        prepare_alt_odb();
 405        for (alt = alt_odb_list; alt; alt = alt->next) {
 406                name = alt->name;
 407                fill_sha1_path(name, sha1);
 408                if (!stat(alt->base, st))
 409                        return alt->base;
 410        }
 411        return NULL;
 412}
 413
 414static unsigned int pack_used_ctr;
 415static unsigned int pack_mmap_calls;
 416static unsigned int peak_pack_open_windows;
 417static unsigned int pack_open_windows;
 418static size_t peak_pack_mapped;
 419static size_t pack_mapped;
 420struct packed_git *packed_git;
 421
 422void pack_report(void)
 423{
 424        fprintf(stderr,
 425                "pack_report: getpagesize()            = %10" SZ_FMT "\n"
 426                "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 427                "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
 428                sz_fmt(getpagesize()),
 429                sz_fmt(packed_git_window_size),
 430                sz_fmt(packed_git_limit));
 431        fprintf(stderr,
 432                "pack_report: pack_used_ctr            = %10u\n"
 433                "pack_report: pack_mmap_calls          = %10u\n"
 434                "pack_report: pack_open_windows        = %10u / %10u\n"
 435                "pack_report: pack_mapped              = "
 436                        "%10" SZ_FMT " / %10" SZ_FMT "\n",
 437                pack_used_ctr,
 438                pack_mmap_calls,
 439                pack_open_windows, peak_pack_open_windows,
 440                sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
 441}
 442
 443static int check_packed_git_idx(const char *path,  struct packed_git *p)
 444{
 445        void *idx_map;
 446        struct pack_idx_header *hdr;
 447        size_t idx_size;
 448        uint32_t version, nr, i, *index;
 449        int fd = open(path, O_RDONLY);
 450        struct stat st;
 451
 452        if (fd < 0)
 453                return -1;
 454        if (fstat(fd, &st)) {
 455                close(fd);
 456                return -1;
 457        }
 458        idx_size = xsize_t(st.st_size);
 459        if (idx_size < 4 * 256 + 20 + 20) {
 460                close(fd);
 461                return error("index file %s is too small", path);
 462        }
 463        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 464        close(fd);
 465
 466        hdr = idx_map;
 467        if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 468                version = ntohl(hdr->idx_version);
 469                if (version < 2 || version > 2) {
 470                        munmap(idx_map, idx_size);
 471                        return error("index file %s is version %d"
 472                                     " and is not supported by this binary"
 473                                     " (try upgrading GIT to a newer version)",
 474                                     path, version);
 475                }
 476        } else
 477                version = 1;
 478
 479        nr = 0;
 480        index = idx_map;
 481        if (version > 1)
 482                index += 2;  /* skip index header */
 483        for (i = 0; i < 256; i++) {
 484                uint32_t n = ntohl(index[i]);
 485                if (n < nr) {
 486                        munmap(idx_map, idx_size);
 487                        return error("non-monotonic index %s", path);
 488                }
 489                nr = n;
 490        }
 491
 492        if (version == 1) {
 493                /*
 494                 * Total size:
 495                 *  - 256 index entries 4 bytes each
 496                 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 497                 *  - 20-byte SHA1 of the packfile
 498                 *  - 20-byte SHA1 file checksum
 499                 */
 500                if (idx_size != 4*256 + nr * 24 + 20 + 20) {
 501                        munmap(idx_map, idx_size);
 502                        return error("wrong index v1 file size in %s", path);
 503                }
 504        } else if (version == 2) {
 505                /*
 506                 * Minimum size:
 507                 *  - 8 bytes of header
 508                 *  - 256 index entries 4 bytes each
 509                 *  - 20-byte sha1 entry * nr
 510                 *  - 4-byte crc entry * nr
 511                 *  - 4-byte offset entry * nr
 512                 *  - 20-byte SHA1 of the packfile
 513                 *  - 20-byte SHA1 file checksum
 514                 * And after the 4-byte offset table might be a
 515                 * variable sized table containing 8-byte entries
 516                 * for offsets larger than 2^31.
 517                 */
 518                unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
 519                unsigned long max_size = min_size;
 520                if (nr)
 521                        max_size += (nr - 1)*8;
 522                if (idx_size < min_size || idx_size > max_size) {
 523                        munmap(idx_map, idx_size);
 524                        return error("wrong index v2 file size in %s", path);
 525                }
 526                if (idx_size != min_size &&
 527                    /*
 528                     * make sure we can deal with large pack offsets.
 529                     * 31-bit signed offset won't be enough, neither
 530                     * 32-bit unsigned one will be.
 531                     */
 532                    (sizeof(off_t) <= 4)) {
 533                        munmap(idx_map, idx_size);
 534                        return error("pack too large for current definition of off_t in %s", path);
 535                }
 536        }
 537
 538        p->index_version = version;
 539        p->index_data = idx_map;
 540        p->index_size = idx_size;
 541        p->num_objects = nr;
 542        return 0;
 543}
 544
 545int open_pack_index(struct packed_git *p)
 546{
 547        char *idx_name;
 548        int ret;
 549
 550        if (p->index_data)
 551                return 0;
 552
 553        idx_name = xstrdup(p->pack_name);
 554        strcpy(idx_name + strlen(idx_name) - strlen(".pack"), ".idx");
 555        ret = check_packed_git_idx(idx_name, p);
 556        free(idx_name);
 557        return ret;
 558}
 559
 560static void scan_windows(struct packed_git *p,
 561        struct packed_git **lru_p,
 562        struct pack_window **lru_w,
 563        struct pack_window **lru_l)
 564{
 565        struct pack_window *w, *w_l;
 566
 567        for (w_l = NULL, w = p->windows; w; w = w->next) {
 568                if (!w->inuse_cnt) {
 569                        if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 570                                *lru_p = p;
 571                                *lru_w = w;
 572                                *lru_l = w_l;
 573                        }
 574                }
 575                w_l = w;
 576        }
 577}
 578
 579static int unuse_one_window(struct packed_git *current, int keep_fd)
 580{
 581        struct packed_git *p, *lru_p = NULL;
 582        struct pack_window *lru_w = NULL, *lru_l = NULL;
 583
 584        if (current)
 585                scan_windows(current, &lru_p, &lru_w, &lru_l);
 586        for (p = packed_git; p; p = p->next)
 587                scan_windows(p, &lru_p, &lru_w, &lru_l);
 588        if (lru_p) {
 589                munmap(lru_w->base, lru_w->len);
 590                pack_mapped -= lru_w->len;
 591                if (lru_l)
 592                        lru_l->next = lru_w->next;
 593                else {
 594                        lru_p->windows = lru_w->next;
 595                        if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
 596                                close(lru_p->pack_fd);
 597                                lru_p->pack_fd = -1;
 598                        }
 599                }
 600                free(lru_w);
 601                pack_open_windows--;
 602                return 1;
 603        }
 604        return 0;
 605}
 606
 607void release_pack_memory(size_t need, int fd)
 608{
 609        size_t cur = pack_mapped;
 610        while (need >= (cur - pack_mapped) && unuse_one_window(NULL, fd))
 611                ; /* nothing */
 612}
 613
 614void unuse_pack(struct pack_window **w_cursor)
 615{
 616        struct pack_window *w = *w_cursor;
 617        if (w) {
 618                w->inuse_cnt--;
 619                *w_cursor = NULL;
 620        }
 621}
 622
 623/*
 624 * Do not call this directly as this leaks p->pack_fd on error return;
 625 * call open_packed_git() instead.
 626 */
 627static int open_packed_git_1(struct packed_git *p)
 628{
 629        struct stat st;
 630        struct pack_header hdr;
 631        unsigned char sha1[20];
 632        unsigned char *idx_sha1;
 633        long fd_flag;
 634
 635        if (!p->index_data && open_pack_index(p))
 636                return error("packfile %s index unavailable", p->pack_name);
 637
 638        p->pack_fd = open(p->pack_name, O_RDONLY);
 639        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 640                return -1;
 641
 642        /* If we created the struct before we had the pack we lack size. */
 643        if (!p->pack_size) {
 644                if (!S_ISREG(st.st_mode))
 645                        return error("packfile %s not a regular file", p->pack_name);
 646                p->pack_size = st.st_size;
 647        } else if (p->pack_size != st.st_size)
 648                return error("packfile %s size changed", p->pack_name);
 649
 650        /* We leave these file descriptors open with sliding mmap;
 651         * there is no point keeping them open across exec(), though.
 652         */
 653        fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 654        if (fd_flag < 0)
 655                return error("cannot determine file descriptor flags");
 656        fd_flag |= FD_CLOEXEC;
 657        if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 658                return error("cannot set FD_CLOEXEC");
 659
 660        /* Verify we recognize this pack file format. */
 661        if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 662                return error("file %s is far too short to be a packfile", p->pack_name);
 663        if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 664                return error("file %s is not a GIT packfile", p->pack_name);
 665        if (!pack_version_ok(hdr.hdr_version))
 666                return error("packfile %s is version %u and not supported"
 667                        " (try upgrading GIT to a newer version)",
 668                        p->pack_name, ntohl(hdr.hdr_version));
 669
 670        /* Verify the pack matches its index. */
 671        if (p->num_objects != ntohl(hdr.hdr_entries))
 672                return error("packfile %s claims to have %u objects"
 673                             " while index indicates %u objects",
 674                             p->pack_name, ntohl(hdr.hdr_entries),
 675                             p->num_objects);
 676        if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
 677                return error("end of packfile %s is unavailable", p->pack_name);
 678        if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
 679                return error("packfile %s signature is unavailable", p->pack_name);
 680        idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
 681        if (hashcmp(sha1, idx_sha1))
 682                return error("packfile %s does not match index", p->pack_name);
 683        return 0;
 684}
 685
 686static int open_packed_git(struct packed_git *p)
 687{
 688        if (!open_packed_git_1(p))
 689                return 0;
 690        if (p->pack_fd != -1) {
 691                close(p->pack_fd);
 692                p->pack_fd = -1;
 693        }
 694        return -1;
 695}
 696
 697static int in_window(struct pack_window *win, off_t offset)
 698{
 699        /* We must promise at least 20 bytes (one hash) after the
 700         * offset is available from this window, otherwise the offset
 701         * is not actually in this window and a different window (which
 702         * has that one hash excess) must be used.  This is to support
 703         * the object header and delta base parsing routines below.
 704         */
 705        off_t win_off = win->offset;
 706        return win_off <= offset
 707                && (offset + 20) <= (win_off + win->len);
 708}
 709
 710unsigned char* use_pack(struct packed_git *p,
 711                struct pack_window **w_cursor,
 712                off_t offset,
 713                unsigned int *left)
 714{
 715        struct pack_window *win = *w_cursor;
 716
 717        if (p->pack_fd == -1 && open_packed_git(p))
 718                die("packfile %s cannot be accessed", p->pack_name);
 719
 720        /* Since packfiles end in a hash of their content and its
 721         * pointless to ask for an offset into the middle of that
 722         * hash, and the in_window function above wouldn't match
 723         * don't allow an offset too close to the end of the file.
 724         */
 725        if (offset > (p->pack_size - 20))
 726                die("offset beyond end of packfile (truncated pack?)");
 727
 728        if (!win || !in_window(win, offset)) {
 729                if (win)
 730                        win->inuse_cnt--;
 731                for (win = p->windows; win; win = win->next) {
 732                        if (in_window(win, offset))
 733                                break;
 734                }
 735                if (!win) {
 736                        size_t window_align = packed_git_window_size / 2;
 737                        off_t len;
 738                        win = xcalloc(1, sizeof(*win));
 739                        win->offset = (offset / window_align) * window_align;
 740                        len = p->pack_size - win->offset;
 741                        if (len > packed_git_window_size)
 742                                len = packed_git_window_size;
 743                        win->len = (size_t)len;
 744                        pack_mapped += win->len;
 745                        while (packed_git_limit < pack_mapped
 746                                && unuse_one_window(p, p->pack_fd))
 747                                ; /* nothing */
 748                        win->base = xmmap(NULL, win->len,
 749                                PROT_READ, MAP_PRIVATE,
 750                                p->pack_fd, win->offset);
 751                        if (win->base == MAP_FAILED)
 752                                die("packfile %s cannot be mapped: %s",
 753                                        p->pack_name,
 754                                        strerror(errno));
 755                        pack_mmap_calls++;
 756                        pack_open_windows++;
 757                        if (pack_mapped > peak_pack_mapped)
 758                                peak_pack_mapped = pack_mapped;
 759                        if (pack_open_windows > peak_pack_open_windows)
 760                                peak_pack_open_windows = pack_open_windows;
 761                        win->next = p->windows;
 762                        p->windows = win;
 763                }
 764        }
 765        if (win != *w_cursor) {
 766                win->last_used = pack_used_ctr++;
 767                win->inuse_cnt++;
 768                *w_cursor = win;
 769        }
 770        offset -= win->offset;
 771        if (left)
 772                *left = win->len - xsize_t(offset);
 773        return win->base + offset;
 774}
 775
 776struct packed_git *add_packed_git(const char *path, int path_len, int local)
 777{
 778        struct stat st;
 779        struct packed_git *p = xmalloc(sizeof(*p) + path_len + 2);
 780
 781        /*
 782         * Make sure a corresponding .pack file exists and that
 783         * the index looks sane.
 784         */
 785        path_len -= strlen(".idx");
 786        if (path_len < 1)
 787                return NULL;
 788        memcpy(p->pack_name, path, path_len);
 789        strcpy(p->pack_name + path_len, ".pack");
 790        if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 791                free(p);
 792                return NULL;
 793        }
 794
 795        /* ok, it looks sane as far as we can check without
 796         * actually mapping the pack file.
 797         */
 798        p->index_version = 0;
 799        p->index_data = NULL;
 800        p->index_size = 0;
 801        p->num_objects = 0;
 802        p->pack_size = st.st_size;
 803        p->next = NULL;
 804        p->windows = NULL;
 805        p->pack_fd = -1;
 806        p->pack_local = local;
 807        p->mtime = st.st_mtime;
 808        if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
 809                hashclr(p->sha1);
 810        return p;
 811}
 812
 813struct packed_git *parse_pack_index(unsigned char *sha1)
 814{
 815        char *path = sha1_pack_index_name(sha1);
 816        return parse_pack_index_file(sha1, path);
 817}
 818
 819struct packed_git *parse_pack_index_file(const unsigned char *sha1,
 820                                         const char *idx_path)
 821{
 822        const char *path = sha1_pack_name(sha1);
 823        struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2);
 824
 825        if (check_packed_git_idx(idx_path, p)) {
 826                free(p);
 827                return NULL;
 828        }
 829
 830        strcpy(p->pack_name, path);
 831        p->pack_size = 0;
 832        p->next = NULL;
 833        p->windows = NULL;
 834        p->pack_fd = -1;
 835        hashcpy(p->sha1, sha1);
 836        return p;
 837}
 838
 839void install_packed_git(struct packed_git *pack)
 840{
 841        pack->next = packed_git;
 842        packed_git = pack;
 843}
 844
 845static void prepare_packed_git_one(char *objdir, int local)
 846{
 847        /* Ensure that this buffer is large enough so that we can
 848           append "/pack/" without clobbering the stack even if
 849           strlen(objdir) were PATH_MAX.  */
 850        char path[PATH_MAX + 1 + 4 + 1 + 1];
 851        int len;
 852        DIR *dir;
 853        struct dirent *de;
 854
 855        sprintf(path, "%s/pack", objdir);
 856        len = strlen(path);
 857        dir = opendir(path);
 858        if (!dir) {
 859                if (errno != ENOENT)
 860                        error("unable to open object pack directory: %s: %s",
 861                              path, strerror(errno));
 862                return;
 863        }
 864        path[len++] = '/';
 865        while ((de = readdir(dir)) != NULL) {
 866                int namelen = strlen(de->d_name);
 867                struct packed_git *p;
 868
 869                if (!has_extension(de->d_name, ".idx"))
 870                        continue;
 871
 872                if (len + namelen + 1 > sizeof(path))
 873                        continue;
 874
 875                /* Don't reopen a pack we already have. */
 876                strcpy(path + len, de->d_name);
 877                for (p = packed_git; p; p = p->next) {
 878                        if (!memcmp(path, p->pack_name, len + namelen - 4))
 879                                break;
 880                }
 881                if (p)
 882                        continue;
 883                /* See if it really is a valid .idx file with corresponding
 884                 * .pack file that we can map.
 885                 */
 886                p = add_packed_git(path, len + namelen, local);
 887                if (!p)
 888                        continue;
 889                install_packed_git(p);
 890        }
 891        closedir(dir);
 892}
 893
 894static int sort_pack(const void *a_, const void *b_)
 895{
 896        struct packed_git *a = *((struct packed_git **)a_);
 897        struct packed_git *b = *((struct packed_git **)b_);
 898        int st;
 899
 900        /*
 901         * Local packs tend to contain objects specific to our
 902         * variant of the project than remote ones.  In addition,
 903         * remote ones could be on a network mounted filesystem.
 904         * Favor local ones for these reasons.
 905         */
 906        st = a->pack_local - b->pack_local;
 907        if (st)
 908                return -st;
 909
 910        /*
 911         * Younger packs tend to contain more recent objects,
 912         * and more recent objects tend to get accessed more
 913         * often.
 914         */
 915        if (a->mtime < b->mtime)
 916                return 1;
 917        else if (a->mtime == b->mtime)
 918                return 0;
 919        return -1;
 920}
 921
 922static void rearrange_packed_git(void)
 923{
 924        struct packed_git **ary, *p;
 925        int i, n;
 926
 927        for (n = 0, p = packed_git; p; p = p->next)
 928                n++;
 929        if (n < 2)
 930                return;
 931
 932        /* prepare an array of packed_git for easier sorting */
 933        ary = xcalloc(n, sizeof(struct packed_git *));
 934        for (n = 0, p = packed_git; p; p = p->next)
 935                ary[n++] = p;
 936
 937        qsort(ary, n, sizeof(struct packed_git *), sort_pack);
 938
 939        /* link them back again */
 940        for (i = 0; i < n - 1; i++)
 941                ary[i]->next = ary[i + 1];
 942        ary[n - 1]->next = NULL;
 943        packed_git = ary[0];
 944
 945        free(ary);
 946}
 947
 948static int prepare_packed_git_run_once = 0;
 949void prepare_packed_git(void)
 950{
 951        struct alternate_object_database *alt;
 952
 953        if (prepare_packed_git_run_once)
 954                return;
 955        prepare_packed_git_one(get_object_directory(), 1);
 956        prepare_alt_odb();
 957        for (alt = alt_odb_list; alt; alt = alt->next) {
 958                alt->name[-1] = 0;
 959                prepare_packed_git_one(alt->base, 0);
 960                alt->name[-1] = '/';
 961        }
 962        rearrange_packed_git();
 963        prepare_packed_git_run_once = 1;
 964}
 965
 966void reprepare_packed_git(void)
 967{
 968        prepare_packed_git_run_once = 0;
 969        prepare_packed_git();
 970}
 971
 972int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 973{
 974        unsigned char real_sha1[20];
 975        hash_sha1_file(map, size, type, real_sha1);
 976        return hashcmp(sha1, real_sha1) ? -1 : 0;
 977}
 978
 979static void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 980{
 981        struct stat st;
 982        void *map;
 983        int fd;
 984        char *filename = find_sha1_file(sha1, &st);
 985
 986        if (!filename) {
 987                return NULL;
 988        }
 989
 990        fd = open(filename, O_RDONLY | sha1_file_open_flag);
 991        if (fd < 0) {
 992                /* See if it works without O_NOATIME */
 993                switch (sha1_file_open_flag) {
 994                default:
 995                        fd = open(filename, O_RDONLY);
 996                        if (fd >= 0)
 997                                break;
 998                /* Fallthrough */
 999                case 0:
1000                        return NULL;
1001                }
1002
1003                /* If it failed once, it will probably fail again.
1004                 * Stop using O_NOATIME
1005                 */
1006                sha1_file_open_flag = 0;
1007        }
1008        *size = xsize_t(st.st_size);
1009        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1010        close(fd);
1011        return map;
1012}
1013
1014static int legacy_loose_object(unsigned char *map)
1015{
1016        unsigned int word;
1017
1018        /*
1019         * Is it a zlib-compressed buffer? If so, the first byte
1020         * must be 0x78 (15-bit window size, deflated), and the
1021         * first 16-bit word is evenly divisible by 31
1022         */
1023        word = (map[0] << 8) + map[1];
1024        if (map[0] == 0x78 && !(word % 31))
1025                return 1;
1026        else
1027                return 0;
1028}
1029
1030unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
1031{
1032        unsigned shift;
1033        unsigned char c;
1034        unsigned long size;
1035        unsigned long used = 0;
1036
1037        c = buf[used++];
1038        *type = (c >> 4) & 7;
1039        size = c & 15;
1040        shift = 4;
1041        while (c & 0x80) {
1042                if (len <= used)
1043                        return 0;
1044                if (sizeof(long) * 8 <= shift)
1045                        return 0;
1046                c = buf[used++];
1047                size += (c & 0x7f) << shift;
1048                shift += 7;
1049        }
1050        *sizep = size;
1051        return used;
1052}
1053
1054static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1055{
1056        unsigned long size, used;
1057        static const char valid_loose_object_type[8] = {
1058                0, /* OBJ_EXT */
1059                1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
1060                0, /* "delta" and others are invalid in a loose object */
1061        };
1062        enum object_type type;
1063
1064        /* Get the data stream */
1065        memset(stream, 0, sizeof(*stream));
1066        stream->next_in = map;
1067        stream->avail_in = mapsize;
1068        stream->next_out = buffer;
1069        stream->avail_out = bufsiz;
1070
1071        if (legacy_loose_object(map)) {
1072                inflateInit(stream);
1073                return inflate(stream, 0);
1074        }
1075
1076
1077        /*
1078         * There used to be a second loose object header format which
1079         * was meant to mimic the in-pack format, allowing for direct
1080         * copy of the object data.  This format turned up not to be
1081         * really worth it and we don't write it any longer.  But we
1082         * can still read it.
1083         */
1084        used = unpack_object_header_gently(map, mapsize, &type, &size);
1085        if (!used || !valid_loose_object_type[type])
1086                return -1;
1087        map += used;
1088        mapsize -= used;
1089
1090        /* Set up the stream for the rest.. */
1091        stream->next_in = map;
1092        stream->avail_in = mapsize;
1093        inflateInit(stream);
1094
1095        /* And generate the fake traditional header */
1096        stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
1097                                         typename(type), size);
1098        return 0;
1099}
1100
1101static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1102{
1103        int bytes = strlen(buffer) + 1;
1104        unsigned char *buf = xmalloc(1+size);
1105        unsigned long n;
1106        int status = Z_OK;
1107
1108        n = stream->total_out - bytes;
1109        if (n > size)
1110                n = size;
1111        memcpy(buf, (char *) buffer + bytes, n);
1112        bytes = n;
1113        if (bytes <= size) {
1114                /*
1115                 * The above condition must be (bytes <= size), not
1116                 * (bytes < size).  In other words, even though we
1117                 * expect no more output and set avail_out to zer0,
1118                 * the input zlib stream may have bytes that express
1119                 * "this concludes the stream", and we *do* want to
1120                 * eat that input.
1121                 *
1122                 * Otherwise we would not be able to test that we
1123                 * consumed all the input to reach the expected size;
1124                 * we also want to check that zlib tells us that all
1125                 * went well with status == Z_STREAM_END at the end.
1126                 */
1127                stream->next_out = buf + bytes;
1128                stream->avail_out = size - bytes;
1129                while (status == Z_OK)
1130                        status = inflate(stream, Z_FINISH);
1131        }
1132        buf[size] = 0;
1133        if (status == Z_STREAM_END && !stream->avail_in) {
1134                inflateEnd(stream);
1135                return buf;
1136        }
1137
1138        if (status < 0)
1139                error("corrupt loose object '%s'", sha1_to_hex(sha1));
1140        else if (stream->avail_in)
1141                error("garbage at end of loose object '%s'",
1142                      sha1_to_hex(sha1));
1143        free(buf);
1144        return NULL;
1145}
1146
1147/*
1148 * We used to just use "sscanf()", but that's actually way
1149 * too permissive for what we want to check. So do an anal
1150 * object header parse by hand.
1151 */
1152static int parse_sha1_header(const char *hdr, unsigned long *sizep)
1153{
1154        char type[10];
1155        int i;
1156        unsigned long size;
1157
1158        /*
1159         * The type can be at most ten bytes (including the
1160         * terminating '\0' that we add), and is followed by
1161         * a space.
1162         */
1163        i = 0;
1164        for (;;) {
1165                char c = *hdr++;
1166                if (c == ' ')
1167                        break;
1168                type[i++] = c;
1169                if (i >= sizeof(type))
1170                        return -1;
1171        }
1172        type[i] = 0;
1173
1174        /*
1175         * The length must follow immediately, and be in canonical
1176         * decimal format (ie "010" is not valid).
1177         */
1178        size = *hdr++ - '0';
1179        if (size > 9)
1180                return -1;
1181        if (size) {
1182                for (;;) {
1183                        unsigned long c = *hdr - '0';
1184                        if (c > 9)
1185                                break;
1186                        hdr++;
1187                        size = size * 10 + c;
1188                }
1189        }
1190        *sizep = size;
1191
1192        /*
1193         * The length must be followed by a zero byte
1194         */
1195        return *hdr ? -1 : type_from_string(type);
1196}
1197
1198static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1199{
1200        int ret;
1201        z_stream stream;
1202        char hdr[8192];
1203
1204        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1205        if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1206                return NULL;
1207
1208        return unpack_sha1_rest(&stream, hdr, *size, sha1);
1209}
1210
1211unsigned long get_size_from_delta(struct packed_git *p,
1212                                  struct pack_window **w_curs,
1213                                  off_t curpos)
1214{
1215        const unsigned char *data;
1216        unsigned char delta_head[20], *in;
1217        z_stream stream;
1218        int st;
1219
1220        memset(&stream, 0, sizeof(stream));
1221        stream.next_out = delta_head;
1222        stream.avail_out = sizeof(delta_head);
1223
1224        inflateInit(&stream);
1225        do {
1226                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1227                stream.next_in = in;
1228                st = inflate(&stream, Z_FINISH);
1229                curpos += stream.next_in - in;
1230        } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1231                 stream.total_out < sizeof(delta_head));
1232        inflateEnd(&stream);
1233        if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head))
1234                die("delta data unpack-initial failed");
1235
1236        /* Examine the initial part of the delta to figure out
1237         * the result size.
1238         */
1239        data = delta_head;
1240
1241        /* ignore base size */
1242        get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1243
1244        /* Read the result size */
1245        return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1246}
1247
1248static off_t get_delta_base(struct packed_git *p,
1249                                    struct pack_window **w_curs,
1250                                    off_t *curpos,
1251                                    enum object_type type,
1252                                    off_t delta_obj_offset)
1253{
1254        unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1255        off_t base_offset;
1256
1257        /* use_pack() assured us we have [base_info, base_info + 20)
1258         * as a range that we can look at without walking off the
1259         * end of the mapped window.  Its actually the hash size
1260         * that is assured.  An OFS_DELTA longer than the hash size
1261         * is stupid, as then a REF_DELTA would be smaller to store.
1262         */
1263        if (type == OBJ_OFS_DELTA) {
1264                unsigned used = 0;
1265                unsigned char c = base_info[used++];
1266                base_offset = c & 127;
1267                while (c & 128) {
1268                        base_offset += 1;
1269                        if (!base_offset || MSB(base_offset, 7))
1270                                die("offset value overflow for delta base object");
1271                        c = base_info[used++];
1272                        base_offset = (base_offset << 7) + (c & 127);
1273                }
1274                base_offset = delta_obj_offset - base_offset;
1275                if (base_offset >= delta_obj_offset)
1276                        die("delta base offset out of bound");
1277                *curpos += used;
1278        } else if (type == OBJ_REF_DELTA) {
1279                /* The base entry _must_ be in the same pack */
1280                base_offset = find_pack_entry_one(base_info, p);
1281                if (!base_offset)
1282                        die("failed to find delta-pack base object %s",
1283                                sha1_to_hex(base_info));
1284                *curpos += 20;
1285        } else
1286                die("I am totally screwed");
1287        return base_offset;
1288}
1289
1290/* forward declaration for a mutually recursive function */
1291static int packed_object_info(struct packed_git *p, off_t offset,
1292                              unsigned long *sizep);
1293
1294static int packed_delta_info(struct packed_git *p,
1295                             struct pack_window **w_curs,
1296                             off_t curpos,
1297                             enum object_type type,
1298                             off_t obj_offset,
1299                             unsigned long *sizep)
1300{
1301        off_t base_offset;
1302
1303        base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1304        type = packed_object_info(p, base_offset, NULL);
1305
1306        /* We choose to only get the type of the base object and
1307         * ignore potentially corrupt pack file that expects the delta
1308         * based on a base with a wrong size.  This saves tons of
1309         * inflate() calls.
1310         */
1311        if (sizep)
1312                *sizep = get_size_from_delta(p, w_curs, curpos);
1313
1314        return type;
1315}
1316
1317static int unpack_object_header(struct packed_git *p,
1318                                struct pack_window **w_curs,
1319                                off_t *curpos,
1320                                unsigned long *sizep)
1321{
1322        unsigned char *base;
1323        unsigned int left;
1324        unsigned long used;
1325        enum object_type type;
1326
1327        /* use_pack() assures us we have [base, base + 20) available
1328         * as a range that we can look at at.  (Its actually the hash
1329         * size that is assured.)  With our object header encoding
1330         * the maximum deflated object size is 2^137, which is just
1331         * insane, so we know won't exceed what we have been given.
1332         */
1333        base = use_pack(p, w_curs, *curpos, &left);
1334        used = unpack_object_header_gently(base, left, &type, sizep);
1335        if (!used)
1336                die("object offset outside of pack file");
1337        *curpos += used;
1338
1339        return type;
1340}
1341
1342const char *packed_object_info_detail(struct packed_git *p,
1343                                      off_t obj_offset,
1344                                      unsigned long *size,
1345                                      unsigned long *store_size,
1346                                      unsigned int *delta_chain_length,
1347                                      unsigned char *base_sha1)
1348{
1349        struct pack_window *w_curs = NULL;
1350        off_t curpos;
1351        unsigned long dummy;
1352        unsigned char *next_sha1;
1353        enum object_type type;
1354
1355        *delta_chain_length = 0;
1356        curpos = obj_offset;
1357        type = unpack_object_header(p, &w_curs, &curpos, size);
1358
1359        for (;;) {
1360                switch (type) {
1361                default:
1362                        die("pack %s contains unknown object type %d",
1363                            p->pack_name, type);
1364                case OBJ_COMMIT:
1365                case OBJ_TREE:
1366                case OBJ_BLOB:
1367                case OBJ_TAG:
1368                        *store_size = 0; /* notyet */
1369                        unuse_pack(&w_curs);
1370                        return typename(type);
1371                case OBJ_OFS_DELTA:
1372                        obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1373                        if (*delta_chain_length == 0) {
1374                                /* TODO: find base_sha1 as pointed by curpos */
1375                                hashclr(base_sha1);
1376                        }
1377                        break;
1378                case OBJ_REF_DELTA:
1379                        next_sha1 = use_pack(p, &w_curs, curpos, NULL);
1380                        if (*delta_chain_length == 0)
1381                                hashcpy(base_sha1, next_sha1);
1382                        obj_offset = find_pack_entry_one(next_sha1, p);
1383                        break;
1384                }
1385                (*delta_chain_length)++;
1386                curpos = obj_offset;
1387                type = unpack_object_header(p, &w_curs, &curpos, &dummy);
1388        }
1389}
1390
1391static int packed_object_info(struct packed_git *p, off_t obj_offset,
1392                              unsigned long *sizep)
1393{
1394        struct pack_window *w_curs = NULL;
1395        unsigned long size;
1396        off_t curpos = obj_offset;
1397        enum object_type type;
1398
1399        type = unpack_object_header(p, &w_curs, &curpos, &size);
1400
1401        switch (type) {
1402        case OBJ_OFS_DELTA:
1403        case OBJ_REF_DELTA:
1404                type = packed_delta_info(p, &w_curs, curpos,
1405                                         type, obj_offset, sizep);
1406                break;
1407        case OBJ_COMMIT:
1408        case OBJ_TREE:
1409        case OBJ_BLOB:
1410        case OBJ_TAG:
1411                if (sizep)
1412                        *sizep = size;
1413                break;
1414        default:
1415                die("pack %s contains unknown object type %d",
1416                    p->pack_name, type);
1417        }
1418        unuse_pack(&w_curs);
1419        return type;
1420}
1421
1422static void *unpack_compressed_entry(struct packed_git *p,
1423                                    struct pack_window **w_curs,
1424                                    off_t curpos,
1425                                    unsigned long size)
1426{
1427        int st;
1428        z_stream stream;
1429        unsigned char *buffer, *in;
1430
1431        buffer = xmalloc(size + 1);
1432        buffer[size] = 0;
1433        memset(&stream, 0, sizeof(stream));
1434        stream.next_out = buffer;
1435        stream.avail_out = size;
1436
1437        inflateInit(&stream);
1438        do {
1439                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1440                stream.next_in = in;
1441                st = inflate(&stream, Z_FINISH);
1442                curpos += stream.next_in - in;
1443        } while (st == Z_OK || st == Z_BUF_ERROR);
1444        inflateEnd(&stream);
1445        if ((st != Z_STREAM_END) || stream.total_out != size) {
1446                free(buffer);
1447                return NULL;
1448        }
1449
1450        return buffer;
1451}
1452
1453#define MAX_DELTA_CACHE (256)
1454
1455static size_t delta_base_cached;
1456
1457static struct delta_base_cache_lru_list {
1458        struct delta_base_cache_lru_list *prev;
1459        struct delta_base_cache_lru_list *next;
1460} delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
1461
1462static struct delta_base_cache_entry {
1463        struct delta_base_cache_lru_list lru;
1464        void *data;
1465        struct packed_git *p;
1466        off_t base_offset;
1467        unsigned long size;
1468        enum object_type type;
1469} delta_base_cache[MAX_DELTA_CACHE];
1470
1471static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
1472{
1473        unsigned long hash;
1474
1475        hash = (unsigned long)p + (unsigned long)base_offset;
1476        hash += (hash >> 8) + (hash >> 16);
1477        return hash % MAX_DELTA_CACHE;
1478}
1479
1480static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
1481        unsigned long *base_size, enum object_type *type, int keep_cache)
1482{
1483        void *ret;
1484        unsigned long hash = pack_entry_hash(p, base_offset);
1485        struct delta_base_cache_entry *ent = delta_base_cache + hash;
1486
1487        ret = ent->data;
1488        if (ret && ent->p == p && ent->base_offset == base_offset)
1489                goto found_cache_entry;
1490        return unpack_entry(p, base_offset, type, base_size);
1491
1492found_cache_entry:
1493        if (!keep_cache) {
1494                ent->data = NULL;
1495                ent->lru.next->prev = ent->lru.prev;
1496                ent->lru.prev->next = ent->lru.next;
1497                delta_base_cached -= ent->size;
1498        } else {
1499                ret = xmemdupz(ent->data, ent->size);
1500        }
1501        *type = ent->type;
1502        *base_size = ent->size;
1503        return ret;
1504}
1505
1506static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1507{
1508        if (ent->data) {
1509                free(ent->data);
1510                ent->data = NULL;
1511                ent->lru.next->prev = ent->lru.prev;
1512                ent->lru.prev->next = ent->lru.next;
1513                delta_base_cached -= ent->size;
1514        }
1515}
1516
1517static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1518        void *base, unsigned long base_size, enum object_type type)
1519{
1520        unsigned long hash = pack_entry_hash(p, base_offset);
1521        struct delta_base_cache_entry *ent = delta_base_cache + hash;
1522        struct delta_base_cache_lru_list *lru;
1523
1524        release_delta_base_cache(ent);
1525        delta_base_cached += base_size;
1526
1527        for (lru = delta_base_cache_lru.next;
1528             delta_base_cached > delta_base_cache_limit
1529             && lru != &delta_base_cache_lru;
1530             lru = lru->next) {
1531                struct delta_base_cache_entry *f = (void *)lru;
1532                if (f->type == OBJ_BLOB)
1533                        release_delta_base_cache(f);
1534        }
1535        for (lru = delta_base_cache_lru.next;
1536             delta_base_cached > delta_base_cache_limit
1537             && lru != &delta_base_cache_lru;
1538             lru = lru->next) {
1539                struct delta_base_cache_entry *f = (void *)lru;
1540                release_delta_base_cache(f);
1541        }
1542
1543        ent->p = p;
1544        ent->base_offset = base_offset;
1545        ent->type = type;
1546        ent->data = base;
1547        ent->size = base_size;
1548        ent->lru.next = &delta_base_cache_lru;
1549        ent->lru.prev = delta_base_cache_lru.prev;
1550        delta_base_cache_lru.prev->next = &ent->lru;
1551        delta_base_cache_lru.prev = &ent->lru;
1552}
1553
1554static void *unpack_delta_entry(struct packed_git *p,
1555                                struct pack_window **w_curs,
1556                                off_t curpos,
1557                                unsigned long delta_size,
1558                                off_t obj_offset,
1559                                enum object_type *type,
1560                                unsigned long *sizep)
1561{
1562        void *delta_data, *result, *base;
1563        unsigned long base_size;
1564        off_t base_offset;
1565
1566        base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
1567        base = cache_or_unpack_entry(p, base_offset, &base_size, type, 0);
1568        if (!base)
1569                die("failed to read delta base object"
1570                    " at %"PRIuMAX" from %s",
1571                    (uintmax_t)base_offset, p->pack_name);
1572
1573        delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
1574        if (!delta_data)
1575                die("failed to unpack compressed delta"
1576                    " at %"PRIuMAX" from %s",
1577                    (uintmax_t)curpos, p->pack_name);
1578        result = patch_delta(base, base_size,
1579                             delta_data, delta_size,
1580                             sizep);
1581        if (!result)
1582                die("failed to apply delta");
1583        free(delta_data);
1584        add_delta_base_cache(p, base_offset, base, base_size, *type);
1585        return result;
1586}
1587
1588void *unpack_entry(struct packed_git *p, off_t obj_offset,
1589                   enum object_type *type, unsigned long *sizep)
1590{
1591        struct pack_window *w_curs = NULL;
1592        off_t curpos = obj_offset;
1593        void *data;
1594
1595        *type = unpack_object_header(p, &w_curs, &curpos, sizep);
1596        switch (*type) {
1597        case OBJ_OFS_DELTA:
1598        case OBJ_REF_DELTA:
1599                data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
1600                                          obj_offset, type, sizep);
1601                break;
1602        case OBJ_COMMIT:
1603        case OBJ_TREE:
1604        case OBJ_BLOB:
1605        case OBJ_TAG:
1606                data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
1607                break;
1608        default:
1609                die("unknown object type %i in %s", *type, p->pack_name);
1610        }
1611        unuse_pack(&w_curs);
1612        return data;
1613}
1614
1615const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1616                                            uint32_t n)
1617{
1618        const unsigned char *index = p->index_data;
1619        if (!index) {
1620                if (open_pack_index(p))
1621                        return NULL;
1622                index = p->index_data;
1623        }
1624        if (n >= p->num_objects)
1625                return NULL;
1626        index += 4 * 256;
1627        if (p->index_version == 1) {
1628                return index + 24 * n + 4;
1629        } else {
1630                index += 8;
1631                return index + 20 * n;
1632        }
1633}
1634
1635static off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1636{
1637        const unsigned char *index = p->index_data;
1638        index += 4 * 256;
1639        if (p->index_version == 1) {
1640                return ntohl(*((uint32_t *)(index + 24 * n)));
1641        } else {
1642                uint32_t off;
1643                index += 8 + p->num_objects * (20 + 4);
1644                off = ntohl(*((uint32_t *)(index + 4 * n)));
1645                if (!(off & 0x80000000))
1646                        return off;
1647                index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1648                return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
1649                                   ntohl(*((uint32_t *)(index + 4)));
1650        }
1651}
1652
1653off_t find_pack_entry_one(const unsigned char *sha1,
1654                                  struct packed_git *p)
1655{
1656        const uint32_t *level1_ofs = p->index_data;
1657        const unsigned char *index = p->index_data;
1658        unsigned hi, lo;
1659
1660        if (!index) {
1661                if (open_pack_index(p))
1662                        return 0;
1663                level1_ofs = p->index_data;
1664                index = p->index_data;
1665        }
1666        if (p->index_version > 1) {
1667                level1_ofs += 2;
1668                index += 8;
1669        }
1670        index += 4 * 256;
1671        hi = ntohl(level1_ofs[*sha1]);
1672        lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1673
1674        do {
1675                unsigned mi = (lo + hi) / 2;
1676                unsigned x = (p->index_version > 1) ? (mi * 20) : (mi * 24 + 4);
1677                int cmp = hashcmp(index + x, sha1);
1678                if (!cmp)
1679                        return nth_packed_object_offset(p, mi);
1680                if (cmp > 0)
1681                        hi = mi;
1682                else
1683                        lo = mi+1;
1684        } while (lo < hi);
1685        return 0;
1686}
1687
1688int matches_pack_name(struct packed_git *p, const char *name)
1689{
1690        const char *last_c, *c;
1691
1692        if (!strcmp(p->pack_name, name))
1693                return 1;
1694
1695        for (c = p->pack_name, last_c = c; *c;)
1696                if (*c == '/')
1697                        last_c = ++c;
1698                else
1699                        ++c;
1700        if (!strcmp(last_c, name))
1701                return 1;
1702
1703        return 0;
1704}
1705
1706static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
1707{
1708        static struct packed_git *last_found = (void *)1;
1709        struct packed_git *p;
1710        off_t offset;
1711
1712        prepare_packed_git();
1713        if (!packed_git)
1714                return 0;
1715        p = (last_found == (void *)1) ? packed_git : last_found;
1716
1717        do {
1718                if (ignore_packed) {
1719                        const char **ig;
1720                        for (ig = ignore_packed; *ig; ig++)
1721                                if (matches_pack_name(p, *ig))
1722                                        break;
1723                        if (*ig)
1724                                goto next;
1725                }
1726
1727                offset = find_pack_entry_one(sha1, p);
1728                if (offset) {
1729                        /*
1730                         * We are about to tell the caller where they can
1731                         * locate the requested object.  We better make
1732                         * sure the packfile is still here and can be
1733                         * accessed before supplying that answer, as
1734                         * it may have been deleted since the index
1735                         * was loaded!
1736                         */
1737                        if (p->pack_fd == -1 && open_packed_git(p)) {
1738                                error("packfile %s cannot be accessed", p->pack_name);
1739                                goto next;
1740                        }
1741                        e->offset = offset;
1742                        e->p = p;
1743                        hashcpy(e->sha1, sha1);
1744                        last_found = p;
1745                        return 1;
1746                }
1747
1748                next:
1749                if (p == last_found)
1750                        p = packed_git;
1751                else
1752                        p = p->next;
1753                if (p == last_found)
1754                        p = p->next;
1755        } while (p);
1756        return 0;
1757}
1758
1759struct packed_git *find_sha1_pack(const unsigned char *sha1,
1760                                  struct packed_git *packs)
1761{
1762        struct packed_git *p;
1763
1764        for (p = packs; p; p = p->next) {
1765                if (find_pack_entry_one(sha1, p))
1766                        return p;
1767        }
1768        return NULL;
1769
1770}
1771
1772static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
1773{
1774        int status;
1775        unsigned long mapsize, size;
1776        void *map;
1777        z_stream stream;
1778        char hdr[32];
1779
1780        map = map_sha1_file(sha1, &mapsize);
1781        if (!map)
1782                return error("unable to find %s", sha1_to_hex(sha1));
1783        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1784                status = error("unable to unpack %s header",
1785                               sha1_to_hex(sha1));
1786        else if ((status = parse_sha1_header(hdr, &size)) < 0)
1787                status = error("unable to parse %s header", sha1_to_hex(sha1));
1788        else if (sizep)
1789                *sizep = size;
1790        inflateEnd(&stream);
1791        munmap(map, mapsize);
1792        return status;
1793}
1794
1795int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1796{
1797        struct pack_entry e;
1798
1799        if (!find_pack_entry(sha1, &e, NULL)) {
1800                reprepare_packed_git();
1801                if (!find_pack_entry(sha1, &e, NULL))
1802                        return sha1_loose_object_info(sha1, sizep);
1803        }
1804        return packed_object_info(e.p, e.offset, sizep);
1805}
1806
1807static void *read_packed_sha1(const unsigned char *sha1,
1808                              enum object_type *type, unsigned long *size)
1809{
1810        struct pack_entry e;
1811
1812        if (!find_pack_entry(sha1, &e, NULL))
1813                return NULL;
1814        else
1815                return cache_or_unpack_entry(e.p, e.offset, size, type, 1);
1816}
1817
1818/*
1819 * This is meant to hold a *small* number of objects that you would
1820 * want read_sha1_file() to be able to return, but yet you do not want
1821 * to write them into the object store (e.g. a browse-only
1822 * application).
1823 */
1824static struct cached_object {
1825        unsigned char sha1[20];
1826        enum object_type type;
1827        void *buf;
1828        unsigned long size;
1829} *cached_objects;
1830static int cached_object_nr, cached_object_alloc;
1831
1832static struct cached_object *find_cached_object(const unsigned char *sha1)
1833{
1834        int i;
1835        struct cached_object *co = cached_objects;
1836
1837        for (i = 0; i < cached_object_nr; i++, co++) {
1838                if (!hashcmp(co->sha1, sha1))
1839                        return co;
1840        }
1841        return NULL;
1842}
1843
1844int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1845                      unsigned char *sha1)
1846{
1847        struct cached_object *co;
1848
1849        hash_sha1_file(buf, len, typename(type), sha1);
1850        if (has_sha1_file(sha1) || find_cached_object(sha1))
1851                return 0;
1852        if (cached_object_alloc <= cached_object_nr) {
1853                cached_object_alloc = alloc_nr(cached_object_alloc);
1854                cached_objects = xrealloc(cached_objects,
1855                                          sizeof(*cached_objects) *
1856                                          cached_object_alloc);
1857        }
1858        co = &cached_objects[cached_object_nr++];
1859        co->size = len;
1860        co->type = type;
1861        co->buf = xmalloc(len);
1862        memcpy(co->buf, buf, len);
1863        hashcpy(co->sha1, sha1);
1864        return 0;
1865}
1866
1867void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
1868                     unsigned long *size)
1869{
1870        unsigned long mapsize;
1871        void *map, *buf;
1872        struct cached_object *co;
1873
1874        co = find_cached_object(sha1);
1875        if (co) {
1876                *type = co->type;
1877                *size = co->size;
1878                return xmemdupz(co->buf, co->size);
1879        }
1880
1881        buf = read_packed_sha1(sha1, type, size);
1882        if (buf)
1883                return buf;
1884        map = map_sha1_file(sha1, &mapsize);
1885        if (map) {
1886                buf = unpack_sha1_file(map, mapsize, type, size, sha1);
1887                munmap(map, mapsize);
1888                return buf;
1889        }
1890        reprepare_packed_git();
1891        return read_packed_sha1(sha1, type, size);
1892}
1893
1894void *read_object_with_reference(const unsigned char *sha1,
1895                                 const char *required_type_name,
1896                                 unsigned long *size,
1897                                 unsigned char *actual_sha1_return)
1898{
1899        enum object_type type, required_type;
1900        void *buffer;
1901        unsigned long isize;
1902        unsigned char actual_sha1[20];
1903
1904        required_type = type_from_string(required_type_name);
1905        hashcpy(actual_sha1, sha1);
1906        while (1) {
1907                int ref_length = -1;
1908                const char *ref_type = NULL;
1909
1910                buffer = read_sha1_file(actual_sha1, &type, &isize);
1911                if (!buffer)
1912                        return NULL;
1913                if (type == required_type) {
1914                        *size = isize;
1915                        if (actual_sha1_return)
1916                                hashcpy(actual_sha1_return, actual_sha1);
1917                        return buffer;
1918                }
1919                /* Handle references */
1920                else if (type == OBJ_COMMIT)
1921                        ref_type = "tree ";
1922                else if (type == OBJ_TAG)
1923                        ref_type = "object ";
1924                else {
1925                        free(buffer);
1926                        return NULL;
1927                }
1928                ref_length = strlen(ref_type);
1929
1930                if (memcmp(buffer, ref_type, ref_length) ||
1931                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1932                        free(buffer);
1933                        return NULL;
1934                }
1935                free(buffer);
1936                /* Now we have the ID of the referred-to object in
1937                 * actual_sha1.  Check again. */
1938        }
1939}
1940
1941static void write_sha1_file_prepare(const void *buf, unsigned long len,
1942                                    const char *type, unsigned char *sha1,
1943                                    char *hdr, int *hdrlen)
1944{
1945        SHA_CTX c;
1946
1947        /* Generate the header */
1948        *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
1949
1950        /* Sha1.. */
1951        SHA1_Init(&c);
1952        SHA1_Update(&c, hdr, *hdrlen);
1953        SHA1_Update(&c, buf, len);
1954        SHA1_Final(sha1, &c);
1955}
1956
1957/*
1958 * Link the tempfile to the final place, possibly creating the
1959 * last directory level as you do so.
1960 *
1961 * Returns the errno on failure, 0 on success.
1962 */
1963static int link_temp_to_file(const char *tmpfile, const char *filename)
1964{
1965        int ret;
1966        char *dir;
1967
1968        if (!link(tmpfile, filename))
1969                return 0;
1970
1971        /*
1972         * Try to mkdir the last path component if that failed.
1973         *
1974         * Re-try the "link()" regardless of whether the mkdir
1975         * succeeds, since a race might mean that somebody
1976         * else succeeded.
1977         */
1978        ret = errno;
1979        dir = strrchr(filename, '/');
1980        if (dir) {
1981                *dir = 0;
1982                if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
1983                        *dir = '/';
1984                        return -2;
1985                }
1986                *dir = '/';
1987                if (!link(tmpfile, filename))
1988                        return 0;
1989                ret = errno;
1990        }
1991        return ret;
1992}
1993
1994/*
1995 * Move the just written object into its final resting place
1996 */
1997int move_temp_to_file(const char *tmpfile, const char *filename)
1998{
1999        int ret = link_temp_to_file(tmpfile, filename);
2000
2001        /*
2002         * Coda hack - coda doesn't like cross-directory links,
2003         * so we fall back to a rename, which will mean that it
2004         * won't be able to check collisions, but that's not a
2005         * big deal.
2006         *
2007         * The same holds for FAT formatted media.
2008         *
2009         * When this succeeds, we just return 0. We have nothing
2010         * left to unlink.
2011         */
2012        if (ret && ret != EEXIST) {
2013                if (!rename(tmpfile, filename))
2014                        return 0;
2015                ret = errno;
2016        }
2017        unlink(tmpfile);
2018        if (ret) {
2019                if (ret != EEXIST) {
2020                        return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
2021                }
2022                /* FIXME!!! Collision check here ? */
2023        }
2024
2025        return 0;
2026}
2027
2028static int write_buffer(int fd, const void *buf, size_t len)
2029{
2030        if (write_in_full(fd, buf, len) < 0)
2031                return error("file write error (%s)", strerror(errno));
2032        return 0;
2033}
2034
2035int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2036                   unsigned char *sha1)
2037{
2038        char hdr[32];
2039        int hdrlen;
2040        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2041        return 0;
2042}
2043
2044int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
2045{
2046        int size, ret;
2047        unsigned char *compressed;
2048        z_stream stream;
2049        unsigned char sha1[20];
2050        char *filename;
2051        static char tmpfile[PATH_MAX];
2052        char hdr[32];
2053        int fd, hdrlen;
2054
2055        /* Normally if we have it in the pack then we do not bother writing
2056         * it out into .git/objects/??/?{38} file.
2057         */
2058        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2059        filename = sha1_file_name(sha1);
2060        if (returnsha1)
2061                hashcpy(returnsha1, sha1);
2062        if (has_sha1_file(sha1))
2063                return 0;
2064        fd = open(filename, O_RDONLY);
2065        if (fd >= 0) {
2066                /*
2067                 * FIXME!!! We might do collision checking here, but we'd
2068                 * need to uncompress the old file and check it. Later.
2069                 */
2070                close(fd);
2071                return 0;
2072        }
2073
2074        if (errno != ENOENT) {
2075                return error("sha1 file %s: %s\n", filename, strerror(errno));
2076        }
2077
2078        snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory());
2079
2080        fd = mkstemp(tmpfile);
2081        if (fd < 0) {
2082                if (errno == EPERM)
2083                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
2084                else
2085                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
2086        }
2087
2088        /* Set it up */
2089        memset(&stream, 0, sizeof(stream));
2090        deflateInit(&stream, zlib_compression_level);
2091        size = 8 + deflateBound(&stream, len+hdrlen);
2092        compressed = xmalloc(size);
2093
2094        /* Compress it */
2095        stream.next_out = compressed;
2096        stream.avail_out = size;
2097
2098        /* First header.. */
2099        stream.next_in = (unsigned char *)hdr;
2100        stream.avail_in = hdrlen;
2101        while (deflate(&stream, 0) == Z_OK)
2102                /* nothing */;
2103
2104        /* Then the data itself.. */
2105        stream.next_in = buf;
2106        stream.avail_in = len;
2107        ret = deflate(&stream, Z_FINISH);
2108        if (ret != Z_STREAM_END)
2109                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
2110
2111        ret = deflateEnd(&stream);
2112        if (ret != Z_OK)
2113                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
2114
2115        size = stream.total_out;
2116
2117        if (write_buffer(fd, compressed, size) < 0)
2118                die("unable to write sha1 file");
2119        fchmod(fd, 0444);
2120        if (close(fd))
2121                die("unable to write sha1 file");
2122        free(compressed);
2123
2124        return move_temp_to_file(tmpfile, filename);
2125}
2126
2127/*
2128 * We need to unpack and recompress the object for writing
2129 * it out to a different file.
2130 */
2131static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
2132{
2133        size_t size;
2134        z_stream stream;
2135        unsigned char *unpacked;
2136        unsigned long len;
2137        enum object_type type;
2138        char hdr[32];
2139        int hdrlen;
2140        void *buf;
2141
2142        /* need to unpack and recompress it by itself */
2143        unpacked = read_packed_sha1(sha1, &type, &len);
2144        if (!unpacked)
2145                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
2146
2147        hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
2148
2149        /* Set it up */
2150        memset(&stream, 0, sizeof(stream));
2151        deflateInit(&stream, zlib_compression_level);
2152        size = deflateBound(&stream, len + hdrlen);
2153        buf = xmalloc(size);
2154
2155        /* Compress it */
2156        stream.next_out = buf;
2157        stream.avail_out = size;
2158
2159        /* First header.. */
2160        stream.next_in = (void *)hdr;
2161        stream.avail_in = hdrlen;
2162        while (deflate(&stream, 0) == Z_OK)
2163                /* nothing */;
2164
2165        /* Then the data itself.. */
2166        stream.next_in = unpacked;
2167        stream.avail_in = len;
2168        while (deflate(&stream, Z_FINISH) == Z_OK)
2169                /* nothing */;
2170        deflateEnd(&stream);
2171        free(unpacked);
2172
2173        *objsize = stream.total_out;
2174        return buf;
2175}
2176
2177int write_sha1_to_fd(int fd, const unsigned char *sha1)
2178{
2179        int retval;
2180        unsigned long objsize;
2181        void *buf = map_sha1_file(sha1, &objsize);
2182
2183        if (buf) {
2184                retval = write_buffer(fd, buf, objsize);
2185                munmap(buf, objsize);
2186                return retval;
2187        }
2188
2189        buf = repack_object(sha1, &objsize);
2190        retval = write_buffer(fd, buf, objsize);
2191        free(buf);
2192        return retval;
2193}
2194
2195int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
2196                       size_t bufsize, size_t *bufposn)
2197{
2198        char tmpfile[PATH_MAX];
2199        int local;
2200        z_stream stream;
2201        unsigned char real_sha1[20];
2202        unsigned char discard[4096];
2203        int ret;
2204        SHA_CTX c;
2205
2206        snprintf(tmpfile, sizeof(tmpfile), "%s/tmp_obj_XXXXXX", get_object_directory());
2207
2208        local = mkstemp(tmpfile);
2209        if (local < 0) {
2210                if (errno == EPERM)
2211                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
2212                else
2213                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
2214        }
2215
2216        memset(&stream, 0, sizeof(stream));
2217
2218        inflateInit(&stream);
2219
2220        SHA1_Init(&c);
2221
2222        do {
2223                ssize_t size;
2224                if (*bufposn) {
2225                        stream.avail_in = *bufposn;
2226                        stream.next_in = (unsigned char *) buffer;
2227                        do {
2228                                stream.next_out = discard;
2229                                stream.avail_out = sizeof(discard);
2230                                ret = inflate(&stream, Z_SYNC_FLUSH);
2231                                SHA1_Update(&c, discard, sizeof(discard) -
2232                                            stream.avail_out);
2233                        } while (stream.avail_in && ret == Z_OK);
2234                        if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
2235                                die("unable to write sha1 file");
2236                        memmove(buffer, buffer + *bufposn - stream.avail_in,
2237                                stream.avail_in);
2238                        *bufposn = stream.avail_in;
2239                        if (ret != Z_OK)
2240                                break;
2241                }
2242                size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
2243                if (size <= 0) {
2244                        close(local);
2245                        unlink(tmpfile);
2246                        if (!size)
2247                                return error("Connection closed?");
2248                        perror("Reading from connection");
2249                        return -1;
2250                }
2251                *bufposn += size;
2252        } while (1);
2253        inflateEnd(&stream);
2254
2255        fchmod(local, 0444);
2256        if (close(local) != 0)
2257                die("unable to write sha1 file");
2258        SHA1_Final(real_sha1, &c);
2259        if (ret != Z_STREAM_END) {
2260                unlink(tmpfile);
2261                return error("File %s corrupted", sha1_to_hex(sha1));
2262        }
2263        if (hashcmp(sha1, real_sha1)) {
2264                unlink(tmpfile);
2265                return error("File %s has bad hash", sha1_to_hex(sha1));
2266        }
2267
2268        return move_temp_to_file(tmpfile, sha1_file_name(sha1));
2269}
2270
2271int has_pack_index(const unsigned char *sha1)
2272{
2273        struct stat st;
2274        if (stat(sha1_pack_index_name(sha1), &st))
2275                return 0;
2276        return 1;
2277}
2278
2279int has_pack_file(const unsigned char *sha1)
2280{
2281        struct stat st;
2282        if (stat(sha1_pack_name(sha1), &st))
2283                return 0;
2284        return 1;
2285}
2286
2287int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
2288{
2289        struct pack_entry e;
2290        return find_pack_entry(sha1, &e, ignore_packed);
2291}
2292
2293int has_sha1_file(const unsigned char *sha1)
2294{
2295        struct stat st;
2296        struct pack_entry e;
2297
2298        if (find_pack_entry(sha1, &e, NULL))
2299                return 1;
2300        return find_sha1_file(sha1, &st) ? 1 : 0;
2301}
2302
2303int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
2304{
2305        struct strbuf buf;
2306        int ret;
2307
2308        strbuf_init(&buf, 0);
2309        if (strbuf_read(&buf, fd, 4096) < 0) {
2310                strbuf_release(&buf);
2311                return -1;
2312        }
2313
2314        if (!type)
2315                type = blob_type;
2316        if (write_object)
2317                ret = write_sha1_file(buf.buf, buf.len, type, sha1);
2318        else
2319                ret = hash_sha1_file(buf.buf, buf.len, type, sha1);
2320        strbuf_release(&buf);
2321
2322        return ret;
2323}
2324
2325int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
2326             enum object_type type, const char *path)
2327{
2328        size_t size = xsize_t(st->st_size);
2329        void *buf = NULL;
2330        int ret, re_allocated = 0;
2331
2332        if (size)
2333                buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2334        close(fd);
2335
2336        if (!type)
2337                type = OBJ_BLOB;
2338
2339        /*
2340         * Convert blobs to git internal format
2341         */
2342        if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
2343                struct strbuf nbuf;
2344                strbuf_init(&nbuf, 0);
2345                if (convert_to_git(path, buf, size, &nbuf)) {
2346                        munmap(buf, size);
2347                        buf = strbuf_detach(&nbuf, &size);
2348                        re_allocated = 1;
2349                }
2350        }
2351
2352        if (write_object)
2353                ret = write_sha1_file(buf, size, typename(type), sha1);
2354        else
2355                ret = hash_sha1_file(buf, size, typename(type), sha1);
2356        if (re_allocated) {
2357                free(buf);
2358                return ret;
2359        }
2360        if (size)
2361                munmap(buf, size);
2362        return ret;
2363}
2364
2365int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
2366{
2367        int fd;
2368        char *target;
2369        size_t len;
2370
2371        switch (st->st_mode & S_IFMT) {
2372        case S_IFREG:
2373                fd = open(path, O_RDONLY);
2374                if (fd < 0)
2375                        return error("open(\"%s\"): %s", path,
2376                                     strerror(errno));
2377                if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
2378                        return error("%s: failed to insert into database",
2379                                     path);
2380                break;
2381        case S_IFLNK:
2382                len = xsize_t(st->st_size);
2383                target = xmalloc(len + 1);
2384                if (readlink(path, target, len + 1) != st->st_size) {
2385                        char *errstr = strerror(errno);
2386                        free(target);
2387                        return error("readlink(\"%s\"): %s", path,
2388                                     errstr);
2389                }
2390                if (!write_object)
2391                        hash_sha1_file(target, len, blob_type, sha1);
2392                else if (write_sha1_file(target, len, blob_type, sha1))
2393                        return error("%s: failed to insert into database",
2394                                     path);
2395                free(target);
2396                break;
2397        case S_IFDIR:
2398                return resolve_gitlink_ref(path, "HEAD", sha1);
2399        default:
2400                return error("%s: unsupported file type", path);
2401        }
2402        return 0;
2403}
2404
2405int read_pack_header(int fd, struct pack_header *header)
2406{
2407        char *c = (char*)header;
2408        ssize_t remaining = sizeof(struct pack_header);
2409        do {
2410                ssize_t r = xread(fd, c, remaining);
2411                if (r <= 0)
2412                        /* "eof before pack header was fully read" */
2413                        return PH_ERROR_EOF;
2414                remaining -= r;
2415                c += r;
2416        } while (remaining > 0);
2417        if (header->hdr_signature != htonl(PACK_SIGNATURE))
2418                /* "protocol error (pack signature mismatch detected)" */
2419                return PH_ERROR_PACK_SIGNATURE;
2420        if (!pack_version_ok(header->hdr_version))
2421                /* "protocol error (pack version unsupported)" */
2422                return PH_ERROR_PROTOCOL;
2423        return 0;
2424}