7f4145c1870e30fc36dfe81b8b659dacedc1bb59
   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
  17#ifndef O_NOATIME
  18#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  19#define O_NOATIME 01000000
  20#else
  21#define O_NOATIME 0
  22#endif
  23#endif
  24
  25const unsigned char null_sha1[20];
  26
  27static unsigned int sha1_file_open_flag = O_NOATIME;
  28
  29static unsigned hexval(char c)
  30{
  31        if (c >= '0' && c <= '9')
  32                return c - '0';
  33        if (c >= 'a' && c <= 'f')
  34                return c - 'a' + 10;
  35        if (c >= 'A' && c <= 'F')
  36                return c - 'A' + 10;
  37        return ~0;
  38}
  39
  40int get_sha1_hex(const char *hex, unsigned char *sha1)
  41{
  42        int i;
  43        for (i = 0; i < 20; i++) {
  44                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  45                if (val & ~0xff)
  46                        return -1;
  47                *sha1++ = val;
  48                hex += 2;
  49        }
  50        return 0;
  51}
  52
  53int safe_create_leading_directories(char *path)
  54{
  55        char *pos = path;
  56        struct stat st;
  57
  58        if (*pos == '/')
  59                pos++;
  60
  61        while (pos) {
  62                pos = strchr(pos, '/');
  63                if (!pos)
  64                        break;
  65                *pos = 0;
  66                if (!stat(path, &st)) {
  67                        /* path exists */
  68                        if (!S_ISDIR(st.st_mode)) {
  69                                *pos = '/';
  70                                return -3;
  71                        }
  72                }
  73                else if (mkdir(path, 0777)) {
  74                        *pos = '/';
  75                        return -1;
  76                }
  77                else if (adjust_shared_perm(path)) {
  78                        *pos = '/';
  79                        return -2;
  80                }
  81                *pos++ = '/';
  82        }
  83        return 0;
  84}
  85
  86char * sha1_to_hex(const unsigned char *sha1)
  87{
  88        static int bufno;
  89        static char hexbuffer[4][50];
  90        static const char hex[] = "0123456789abcdef";
  91        char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
  92        int i;
  93
  94        for (i = 0; i < 20; i++) {
  95                unsigned int val = *sha1++;
  96                *buf++ = hex[val >> 4];
  97                *buf++ = hex[val & 0xf];
  98        }
  99        *buf = '\0';
 100
 101        return buffer;
 102}
 103
 104static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 105{
 106        int i;
 107        for (i = 0; i < 20; i++) {
 108                static char hex[] = "0123456789abcdef";
 109                unsigned int val = sha1[i];
 110                char *pos = pathbuf + i*2 + (i > 0);
 111                *pos++ = hex[val >> 4];
 112                *pos = hex[val & 0xf];
 113        }
 114}
 115
 116/*
 117 * NOTE! This returns a statically allocated buffer, so you have to be
 118 * careful about using it. Do a "strdup()" if you need to save the
 119 * filename.
 120 *
 121 * Also note that this returns the location for creating.  Reading
 122 * SHA1 file can happen from any alternate directory listed in the
 123 * DB_ENVIRONMENT environment variable if it is not found in
 124 * the primary object database.
 125 */
 126char *sha1_file_name(const unsigned char *sha1)
 127{
 128        static char *name, *base;
 129
 130        if (!base) {
 131                const char *sha1_file_directory = get_object_directory();
 132                int len = strlen(sha1_file_directory);
 133                base = xmalloc(len + 60);
 134                memcpy(base, sha1_file_directory, len);
 135                memset(base+len, 0, 60);
 136                base[len] = '/';
 137                base[len+3] = '/';
 138                name = base + len + 1;
 139        }
 140        fill_sha1_path(name, sha1);
 141        return base;
 142}
 143
 144char *sha1_pack_name(const unsigned char *sha1)
 145{
 146        static const char hex[] = "0123456789abcdef";
 147        static char *name, *base, *buf;
 148        int i;
 149
 150        if (!base) {
 151                const char *sha1_file_directory = get_object_directory();
 152                int len = strlen(sha1_file_directory);
 153                base = xmalloc(len + 60);
 154                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 155                name = base + len + 11;
 156        }
 157
 158        buf = name;
 159
 160        for (i = 0; i < 20; i++) {
 161                unsigned int val = *sha1++;
 162                *buf++ = hex[val >> 4];
 163                *buf++ = hex[val & 0xf];
 164        }
 165        
 166        return base;
 167}
 168
 169char *sha1_pack_index_name(const unsigned char *sha1)
 170{
 171        static const char hex[] = "0123456789abcdef";
 172        static char *name, *base, *buf;
 173        int i;
 174
 175        if (!base) {
 176                const char *sha1_file_directory = get_object_directory();
 177                int len = strlen(sha1_file_directory);
 178                base = xmalloc(len + 60);
 179                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 180                name = base + len + 11;
 181        }
 182
 183        buf = name;
 184
 185        for (i = 0; i < 20; i++) {
 186                unsigned int val = *sha1++;
 187                *buf++ = hex[val >> 4];
 188                *buf++ = hex[val & 0xf];
 189        }
 190        
 191        return base;
 192}
 193
 194struct alternate_object_database *alt_odb_list;
 195static struct alternate_object_database **alt_odb_tail;
 196
 197static void read_info_alternates(const char * alternates, int depth);
 198
 199/*
 200 * Prepare alternate object database registry.
 201 *
 202 * The variable alt_odb_list points at the list of struct
 203 * alternate_object_database.  The elements on this list come from
 204 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 205 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 206 * whose contents is similar to that environment variable but can be
 207 * LF separated.  Its base points at a statically allocated buffer that
 208 * contains "/the/directory/corresponding/to/.git/objects/...", while
 209 * its name points just after the slash at the end of ".git/objects/"
 210 * in the example above, and has enough space to hold 40-byte hex
 211 * SHA1, an extra slash for the first level indirection, and the
 212 * terminating NUL.
 213 */
 214static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 215{
 216        struct stat st;
 217        const char *objdir = get_object_directory();
 218        struct alternate_object_database *ent;
 219        struct alternate_object_database *alt;
 220        /* 43 = 40-byte + 2 '/' + terminating NUL */
 221        int pfxlen = len;
 222        int entlen = pfxlen + 43;
 223        int base_len = -1;
 224
 225        if (*entry != '/' && relative_base) {
 226                /* Relative alt-odb */
 227                if (base_len < 0)
 228                        base_len = strlen(relative_base) + 1;
 229                entlen += base_len;
 230                pfxlen += base_len;
 231        }
 232        ent = xmalloc(sizeof(*ent) + entlen);
 233
 234        if (*entry != '/' && relative_base) {
 235                memcpy(ent->base, relative_base, base_len - 1);
 236                ent->base[base_len - 1] = '/';
 237                memcpy(ent->base + base_len, entry, len);
 238        }
 239        else
 240                memcpy(ent->base, entry, pfxlen);
 241
 242        ent->name = ent->base + pfxlen + 1;
 243        ent->base[pfxlen + 3] = '/';
 244        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 245
 246        /* Detect cases where alternate disappeared */
 247        if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 248                error("object directory %s does not exist; "
 249                      "check .git/objects/info/alternates.",
 250                      ent->base);
 251                free(ent);
 252                return -1;
 253        }
 254
 255        /* Prevent the common mistake of listing the same
 256         * thing twice, or object directory itself.
 257         */
 258        for (alt = alt_odb_list; alt; alt = alt->next) {
 259                if (!memcmp(ent->base, alt->base, pfxlen)) {
 260                        free(ent);
 261                        return -1;
 262                }
 263        }
 264        if (!memcmp(ent->base, objdir, pfxlen)) {
 265                free(ent);
 266                return -1;
 267        }
 268
 269        /* add the alternate entry */
 270        *alt_odb_tail = ent;
 271        alt_odb_tail = &(ent->next);
 272        ent->next = NULL;
 273
 274        /* recursively add alternates */
 275        read_info_alternates(ent->base, depth + 1);
 276
 277        ent->base[pfxlen] = '/';
 278
 279        return 0;
 280}
 281
 282static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 283                                 const char *relative_base, int depth)
 284{
 285        const char *cp, *last;
 286
 287        if (depth > 5) {
 288                error("%s: ignoring alternate object stores, nesting too deep.",
 289                                relative_base);
 290                return;
 291        }
 292
 293        last = alt;
 294        while (last < ep) {
 295                cp = last;
 296                if (cp < ep && *cp == '#') {
 297                        while (cp < ep && *cp != sep)
 298                                cp++;
 299                        last = cp + 1;
 300                        continue;
 301                }
 302                while (cp < ep && *cp != sep)
 303                        cp++;
 304                if (last != cp) {
 305                        if ((*last != '/') && depth) {
 306                                error("%s: ignoring relative alternate object store %s",
 307                                                relative_base, last);
 308                        } else {
 309                                link_alt_odb_entry(last, cp - last,
 310                                                relative_base, depth);
 311                        }
 312                }
 313                while (cp < ep && *cp == sep)
 314                        cp++;
 315                last = cp;
 316        }
 317}
 318
 319static void read_info_alternates(const char * relative_base, int depth)
 320{
 321        char *map;
 322        struct stat st;
 323        char path[PATH_MAX];
 324        int fd;
 325
 326        sprintf(path, "%s/info/alternates", relative_base);
 327        fd = open(path, O_RDONLY);
 328        if (fd < 0)
 329                return;
 330        if (fstat(fd, &st) || (st.st_size == 0)) {
 331                close(fd);
 332                return;
 333        }
 334        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 335        close(fd);
 336        if (map == MAP_FAILED)
 337                return;
 338
 339        link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
 340
 341        munmap(map, st.st_size);
 342}
 343
 344void prepare_alt_odb(void)
 345{
 346        const char *alt;
 347
 348        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 349        if (!alt) alt = "";
 350
 351        if (alt_odb_tail)
 352                return;
 353        alt_odb_tail = &alt_odb_list;
 354        link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 355
 356        read_info_alternates(get_object_directory(), 0);
 357}
 358
 359static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 360{
 361        char *name = sha1_file_name(sha1);
 362        struct alternate_object_database *alt;
 363
 364        if (!stat(name, st))
 365                return name;
 366        prepare_alt_odb();
 367        for (alt = alt_odb_list; alt; alt = alt->next) {
 368                name = alt->name;
 369                fill_sha1_path(name, sha1);
 370                if (!stat(alt->base, st))
 371                        return alt->base;
 372        }
 373        return NULL;
 374}
 375
 376#define PACK_MAX_SZ (1<<26)
 377static int pack_used_ctr;
 378static unsigned long pack_mapped;
 379struct packed_git *packed_git;
 380
 381static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 382                                void **idx_map_)
 383{
 384        void *idx_map;
 385        unsigned int *index;
 386        unsigned long idx_size;
 387        int nr, i;
 388        int fd = open(path, O_RDONLY);
 389        struct stat st;
 390        if (fd < 0)
 391                return -1;
 392        if (fstat(fd, &st)) {
 393                close(fd);
 394                return -1;
 395        }
 396        idx_size = st.st_size;
 397        idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 398        close(fd);
 399        if (idx_map == MAP_FAILED)
 400                return -1;
 401
 402        index = idx_map;
 403        *idx_map_ = idx_map;
 404        *idx_size_ = idx_size;
 405
 406        /* check index map */
 407        if (idx_size < 4*256 + 20 + 20)
 408                return error("index file too small");
 409        nr = 0;
 410        for (i = 0; i < 256; i++) {
 411                unsigned int n = ntohl(index[i]);
 412                if (n < nr)
 413                        return error("non-monotonic index");
 414                nr = n;
 415        }
 416
 417        /*
 418         * Total size:
 419         *  - 256 index entries 4 bytes each
 420         *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 421         *  - 20-byte SHA1 of the packfile
 422         *  - 20-byte SHA1 file checksum
 423         */
 424        if (idx_size != 4*256 + nr * 24 + 20 + 20)
 425                return error("wrong index file size");
 426
 427        return 0;
 428}
 429
 430static int unuse_one_packed_git(void)
 431{
 432        struct packed_git *p, *lru = NULL;
 433
 434        for (p = packed_git; p; p = p->next) {
 435                if (p->pack_use_cnt || !p->pack_base)
 436                        continue;
 437                if (!lru || p->pack_last_used < lru->pack_last_used)
 438                        lru = p;
 439        }
 440        if (!lru)
 441                return 0;
 442        munmap(lru->pack_base, lru->pack_size);
 443        lru->pack_base = NULL;
 444        return 1;
 445}
 446
 447void unuse_packed_git(struct packed_git *p)
 448{
 449        p->pack_use_cnt--;
 450}
 451
 452int use_packed_git(struct packed_git *p)
 453{
 454        if (!p->pack_size) {
 455                struct stat st;
 456                /* We created the struct before we had the pack */
 457                stat(p->pack_name, &st);
 458                if (!S_ISREG(st.st_mode))
 459                        die("packfile %s not a regular file", p->pack_name);
 460                p->pack_size = st.st_size;
 461        }
 462        if (!p->pack_base) {
 463                int fd;
 464                struct stat st;
 465                void *map;
 466                struct pack_header *hdr;
 467
 468                pack_mapped += p->pack_size;
 469                while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 470                        ; /* nothing */
 471                fd = open(p->pack_name, O_RDONLY);
 472                if (fd < 0)
 473                        die("packfile %s cannot be opened", p->pack_name);
 474                if (fstat(fd, &st)) {
 475                        close(fd);
 476                        die("packfile %s cannot be opened", p->pack_name);
 477                }
 478                if (st.st_size != p->pack_size)
 479                        die("packfile %s size mismatch.", p->pack_name);
 480                map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 481                close(fd);
 482                if (map == MAP_FAILED)
 483                        die("packfile %s cannot be mapped.", p->pack_name);
 484                p->pack_base = map;
 485
 486                /* Check if we understand this pack file.  If we don't we're
 487                 * likely too old to handle it.
 488                 */
 489                hdr = map;
 490                if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 491                        die("packfile %s isn't actually a pack.", p->pack_name);
 492                if (!pack_version_ok(hdr->hdr_version))
 493                        die("packfile %s is version %i and not supported"
 494                                " (try upgrading GIT to a newer version)",
 495                                p->pack_name, ntohl(hdr->hdr_version));
 496
 497                /* Check if the pack file matches with the index file.
 498                 * this is cheap.
 499                 */
 500                if (hashcmp((unsigned char *)(p->index_base) +
 501                            p->index_size - 40,
 502                            (unsigned char *)p->pack_base +
 503                            p->pack_size - 20)) {
 504                        die("packfile %s does not match index.", p->pack_name);
 505                }
 506        }
 507        p->pack_last_used = pack_used_ctr++;
 508        p->pack_use_cnt++;
 509        return 0;
 510}
 511
 512struct packed_git *add_packed_git(char *path, int path_len, int local)
 513{
 514        struct stat st;
 515        struct packed_git *p;
 516        unsigned long idx_size;
 517        void *idx_map;
 518        unsigned char sha1[20];
 519
 520        if (check_packed_git_idx(path, &idx_size, &idx_map))
 521                return NULL;
 522
 523        /* do we have a corresponding .pack file? */
 524        strcpy(path + path_len - 4, ".pack");
 525        if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 526                munmap(idx_map, idx_size);
 527                return NULL;
 528        }
 529        /* ok, it looks sane as far as we can check without
 530         * actually mapping the pack file.
 531         */
 532        p = xmalloc(sizeof(*p) + path_len + 2);
 533        strcpy(p->pack_name, path);
 534        p->index_size = idx_size;
 535        p->pack_size = st.st_size;
 536        p->index_base = idx_map;
 537        p->next = NULL;
 538        p->pack_base = NULL;
 539        p->pack_last_used = 0;
 540        p->pack_use_cnt = 0;
 541        p->pack_local = local;
 542        if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 543                hashcpy(p->sha1, sha1);
 544        return p;
 545}
 546
 547struct packed_git *parse_pack_index(unsigned char *sha1)
 548{
 549        char *path = sha1_pack_index_name(sha1);
 550        return parse_pack_index_file(sha1, path);
 551}
 552
 553struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 554{
 555        struct packed_git *p;
 556        unsigned long idx_size;
 557        void *idx_map;
 558        char *path;
 559
 560        if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 561                return NULL;
 562
 563        path = sha1_pack_name(sha1);
 564
 565        p = xmalloc(sizeof(*p) + strlen(path) + 2);
 566        strcpy(p->pack_name, path);
 567        p->index_size = idx_size;
 568        p->pack_size = 0;
 569        p->index_base = idx_map;
 570        p->next = NULL;
 571        p->pack_base = NULL;
 572        p->pack_last_used = 0;
 573        p->pack_use_cnt = 0;
 574        hashcpy(p->sha1, sha1);
 575        return p;
 576}
 577
 578void install_packed_git(struct packed_git *pack)
 579{
 580        pack->next = packed_git;
 581        packed_git = pack;
 582}
 583
 584static void prepare_packed_git_one(char *objdir, int local)
 585{
 586        char path[PATH_MAX];
 587        int len;
 588        DIR *dir;
 589        struct dirent *de;
 590
 591        sprintf(path, "%s/pack", objdir);
 592        len = strlen(path);
 593        dir = opendir(path);
 594        if (!dir) {
 595                if (errno != ENOENT)
 596                        error("unable to open object pack directory: %s: %s",
 597                              path, strerror(errno));
 598                return;
 599        }
 600        path[len++] = '/';
 601        while ((de = readdir(dir)) != NULL) {
 602                int namelen = strlen(de->d_name);
 603                struct packed_git *p;
 604
 605                if (!has_extension(de->d_name, ".idx"))
 606                        continue;
 607
 608                /* we have .idx.  Is it a file we can map? */
 609                strcpy(path + len, de->d_name);
 610                for (p = packed_git; p; p = p->next) {
 611                        if (!memcmp(path, p->pack_name, len + namelen - 4))
 612                                break;
 613                }
 614                if (p)
 615                        continue;
 616                p = add_packed_git(path, len + namelen, local);
 617                if (!p)
 618                        continue;
 619                p->next = packed_git;
 620                packed_git = p;
 621        }
 622        closedir(dir);
 623}
 624
 625static int prepare_packed_git_run_once = 0;
 626void prepare_packed_git(void)
 627{
 628        struct alternate_object_database *alt;
 629
 630        if (prepare_packed_git_run_once)
 631                return;
 632        prepare_packed_git_one(get_object_directory(), 1);
 633        prepare_alt_odb();
 634        for (alt = alt_odb_list; alt; alt = alt->next) {
 635                alt->name[-1] = 0;
 636                prepare_packed_git_one(alt->base, 0);
 637                alt->name[-1] = '/';
 638        }
 639        prepare_packed_git_run_once = 1;
 640}
 641
 642static void reprepare_packed_git(void)
 643{
 644        prepare_packed_git_run_once = 0;
 645        prepare_packed_git();
 646}
 647
 648int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 649{
 650        char header[100];
 651        unsigned char real_sha1[20];
 652        SHA_CTX c;
 653
 654        SHA1_Init(&c);
 655        SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 656        SHA1_Update(&c, map, size);
 657        SHA1_Final(real_sha1, &c);
 658        return hashcmp(sha1, real_sha1) ? -1 : 0;
 659}
 660
 661void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 662{
 663        struct stat st;
 664        void *map;
 665        int fd;
 666        char *filename = find_sha1_file(sha1, &st);
 667
 668        if (!filename) {
 669                return NULL;
 670        }
 671
 672        fd = open(filename, O_RDONLY | sha1_file_open_flag);
 673        if (fd < 0) {
 674                /* See if it works without O_NOATIME */
 675                switch (sha1_file_open_flag) {
 676                default:
 677                        fd = open(filename, O_RDONLY);
 678                        if (fd >= 0)
 679                                break;
 680                /* Fallthrough */
 681                case 0:
 682                        return NULL;
 683                }
 684
 685                /* If it failed once, it will probably fail again.
 686                 * Stop using O_NOATIME
 687                 */
 688                sha1_file_open_flag = 0;
 689        }
 690        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 691        close(fd);
 692        if (map == MAP_FAILED)
 693                return NULL;
 694        *size = st.st_size;
 695        return map;
 696}
 697
 698int legacy_loose_object(unsigned char *map)
 699{
 700        unsigned int word;
 701
 702        /*
 703         * Is it a zlib-compressed buffer? If so, the first byte
 704         * must be 0x78 (15-bit window size, deflated), and the
 705         * first 16-bit word is evenly divisible by 31
 706         */
 707        word = (map[0] << 8) + map[1];
 708        if (map[0] == 0x78 && !(word % 31))
 709                return 1;
 710        else
 711                return 0;
 712}
 713
 714static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 715{
 716        unsigned char c;
 717        unsigned int bits;
 718        unsigned long size;
 719        static const char *typename[8] = {
 720                NULL,   /* OBJ_EXT */
 721                "commit", "tree", "blob", "tag",
 722                NULL, NULL, NULL
 723        };
 724        const char *type;
 725
 726        /* Get the data stream */
 727        memset(stream, 0, sizeof(*stream));
 728        stream->next_in = map;
 729        stream->avail_in = mapsize;
 730        stream->next_out = buffer;
 731        stream->avail_out = bufsiz;
 732
 733        if (legacy_loose_object(map)) {
 734                inflateInit(stream);
 735                return inflate(stream, 0);
 736        }
 737
 738        c = *map++;
 739        mapsize--;
 740        type = typename[(c >> 4) & 7];
 741        if (!type)
 742                return -1;
 743
 744        bits = 4;
 745        size = c & 0xf;
 746        while ((c & 0x80)) {
 747                if (bits >= 8*sizeof(long))
 748                        return -1;
 749                c = *map++;
 750                size += (c & 0x7f) << bits;
 751                bits += 7;
 752                mapsize--;
 753        }
 754
 755        /* Set up the stream for the rest.. */
 756        stream->next_in = map;
 757        stream->avail_in = mapsize;
 758        inflateInit(stream);
 759
 760        /* And generate the fake traditional header */
 761        stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu", type, size);
 762        return 0;
 763}
 764
 765static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 766{
 767        int bytes = strlen(buffer) + 1;
 768        unsigned char *buf = xmalloc(1+size);
 769        unsigned long n;
 770
 771        n = stream->total_out - bytes;
 772        if (n > size)
 773                n = size;
 774        memcpy(buf, (char *) buffer + bytes, n);
 775        bytes = n;
 776        if (bytes < size) {
 777                stream->next_out = buf + bytes;
 778                stream->avail_out = size - bytes;
 779                while (inflate(stream, Z_FINISH) == Z_OK)
 780                        /* nothing */;
 781        }
 782        buf[size] = 0;
 783        inflateEnd(stream);
 784        return buf;
 785}
 786
 787/*
 788 * We used to just use "sscanf()", but that's actually way
 789 * too permissive for what we want to check. So do an anal
 790 * object header parse by hand.
 791 */
 792static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 793{
 794        int i;
 795        unsigned long size;
 796
 797        /*
 798         * The type can be at most ten bytes (including the 
 799         * terminating '\0' that we add), and is followed by
 800         * a space. 
 801         */
 802        i = 10;
 803        for (;;) {
 804                char c = *hdr++;
 805                if (c == ' ')
 806                        break;
 807                if (!--i)
 808                        return -1;
 809                *type++ = c;
 810        }
 811        *type = 0;
 812
 813        /*
 814         * The length must follow immediately, and be in canonical
 815         * decimal format (ie "010" is not valid).
 816         */
 817        size = *hdr++ - '0';
 818        if (size > 9)
 819                return -1;
 820        if (size) {
 821                for (;;) {
 822                        unsigned long c = *hdr - '0';
 823                        if (c > 9)
 824                                break;
 825                        hdr++;
 826                        size = size * 10 + c;
 827                }
 828        }
 829        *sizep = size;
 830
 831        /*
 832         * The length must be followed by a zero byte
 833         */
 834        return *hdr ? -1 : 0;
 835}
 836
 837void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 838{
 839        int ret;
 840        z_stream stream;
 841        char hdr[8192];
 842
 843        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 844        if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 845                return NULL;
 846
 847        return unpack_sha1_rest(&stream, hdr, *size);
 848}
 849
 850/* forward declaration for a mutually recursive function */
 851static int packed_object_info(struct pack_entry *entry,
 852                              char *type, unsigned long *sizep);
 853
 854static int packed_delta_info(unsigned char *base_sha1,
 855                             unsigned long delta_size,
 856                             unsigned long left,
 857                             char *type,
 858                             unsigned long *sizep,
 859                             struct packed_git *p)
 860{
 861        struct pack_entry base_ent;
 862
 863        if (left < 20)
 864                die("truncated pack file");
 865
 866        /* The base entry _must_ be in the same pack */
 867        if (!find_pack_entry_one(base_sha1, &base_ent, p))
 868                die("failed to find delta-pack base object %s",
 869                    sha1_to_hex(base_sha1));
 870
 871        /* We choose to only get the type of the base object and
 872         * ignore potentially corrupt pack file that expects the delta
 873         * based on a base with a wrong size.  This saves tons of
 874         * inflate() calls.
 875         */
 876
 877        if (packed_object_info(&base_ent, type, NULL))
 878                die("cannot get info for delta-pack base");
 879
 880        if (sizep) {
 881                const unsigned char *data;
 882                unsigned char delta_head[64];
 883                unsigned long result_size;
 884                z_stream stream;
 885                int st;
 886
 887                memset(&stream, 0, sizeof(stream));
 888
 889                data = stream.next_in = base_sha1 + 20;
 890                stream.avail_in = left - 20;
 891                stream.next_out = delta_head;
 892                stream.avail_out = sizeof(delta_head);
 893
 894                inflateInit(&stream);
 895                st = inflate(&stream, Z_FINISH);
 896                inflateEnd(&stream);
 897                if ((st != Z_STREAM_END) &&
 898                    stream.total_out != sizeof(delta_head))
 899                        die("delta data unpack-initial failed");
 900
 901                /* Examine the initial part of the delta to figure out
 902                 * the result size.
 903                 */
 904                data = delta_head;
 905
 906                /* ignore base size */
 907                get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 908
 909                /* Read the result size */
 910                result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 911                *sizep = result_size;
 912        }
 913        return 0;
 914}
 915
 916static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 917        enum object_type *type, unsigned long *sizep)
 918{
 919        unsigned shift;
 920        unsigned char c;
 921        unsigned long size;
 922
 923        if (offset >= p->pack_size)
 924                die("object offset outside of pack file");
 925        c = *((unsigned char *)p->pack_base + offset++);
 926        *type = (c >> 4) & 7;
 927        size = c & 15;
 928        shift = 4;
 929        while (c & 0x80) {
 930                if (offset >= p->pack_size)
 931                        die("object offset outside of pack file");
 932                c = *((unsigned char *)p->pack_base + offset++);
 933                size += (c & 0x7f) << shift;
 934                shift += 7;
 935        }
 936        *sizep = size;
 937        return offset;
 938}
 939
 940int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 941                           unsigned char *base, unsigned long *sizep,
 942                           enum object_type *kindp)
 943{
 944        unsigned long ptr;
 945        int status = -1;
 946
 947        use_packed_git(p);
 948        ptr = offset;
 949        ptr = unpack_object_header(p, ptr, kindp, sizep);
 950        if (*kindp != OBJ_DELTA)
 951                goto done;
 952        hashcpy(base, (unsigned char *) p->pack_base + ptr);
 953        status = 0;
 954 done:
 955        unuse_packed_git(p);
 956        return status;
 957}
 958
 959void packed_object_info_detail(struct pack_entry *e,
 960                               char *type,
 961                               unsigned long *size,
 962                               unsigned long *store_size,
 963                               unsigned int *delta_chain_length,
 964                               unsigned char *base_sha1)
 965{
 966        struct packed_git *p = e->p;
 967        unsigned long offset;
 968        unsigned char *pack;
 969        enum object_type kind;
 970
 971        offset = unpack_object_header(p, e->offset, &kind, size);
 972        pack = (unsigned char *) p->pack_base + offset;
 973        if (kind != OBJ_DELTA)
 974                *delta_chain_length = 0;
 975        else {
 976                unsigned int chain_length = 0;
 977                if (p->pack_size <= offset + 20)
 978                        die("pack file %s records an incomplete delta base",
 979                            p->pack_name);
 980                hashcpy(base_sha1, pack);
 981                do {
 982                        struct pack_entry base_ent;
 983                        unsigned long junk;
 984
 985                        find_pack_entry_one(pack, &base_ent, p);
 986                        offset = unpack_object_header(p, base_ent.offset,
 987                                                      &kind, &junk);
 988                        pack = (unsigned char *) p->pack_base + offset;
 989                        chain_length++;
 990                } while (kind == OBJ_DELTA);
 991                *delta_chain_length = chain_length;
 992        }
 993        switch (kind) {
 994        case OBJ_COMMIT:
 995        case OBJ_TREE:
 996        case OBJ_BLOB:
 997        case OBJ_TAG:
 998                strcpy(type, type_names[kind]);
 999                break;
1000        default:
1001                die("corrupted pack file %s containing object of kind %d",
1002                    p->pack_name, kind);
1003        }
1004        *store_size = 0; /* notyet */
1005}
1006
1007static int packed_object_info(struct pack_entry *entry,
1008                              char *type, unsigned long *sizep)
1009{
1010        struct packed_git *p = entry->p;
1011        unsigned long offset, size, left;
1012        unsigned char *pack;
1013        enum object_type kind;
1014        int retval;
1015
1016        if (use_packed_git(p))
1017                die("cannot map packed file");
1018
1019        offset = unpack_object_header(p, entry->offset, &kind, &size);
1020        pack = (unsigned char *) p->pack_base + offset;
1021        left = p->pack_size - offset;
1022
1023        switch (kind) {
1024        case OBJ_DELTA:
1025                retval = packed_delta_info(pack, size, left, type, sizep, p);
1026                unuse_packed_git(p);
1027                return retval;
1028        case OBJ_COMMIT:
1029        case OBJ_TREE:
1030        case OBJ_BLOB:
1031        case OBJ_TAG:
1032                strcpy(type, type_names[kind]);
1033                break;
1034        default:
1035                die("corrupted pack file %s containing object of kind %d",
1036                    p->pack_name, kind);
1037        }
1038        if (sizep)
1039                *sizep = size;
1040        unuse_packed_git(p);
1041        return 0;
1042}
1043
1044static void *unpack_compressed_entry(unsigned char *data,
1045                                    unsigned long size,
1046                                    unsigned long left)
1047{
1048        int st;
1049        z_stream stream;
1050        unsigned char *buffer;
1051
1052        buffer = xmalloc(size + 1);
1053        buffer[size] = 0;
1054        memset(&stream, 0, sizeof(stream));
1055        stream.next_in = data;
1056        stream.avail_in = left;
1057        stream.next_out = buffer;
1058        stream.avail_out = size;
1059
1060        inflateInit(&stream);
1061        st = inflate(&stream, Z_FINISH);
1062        inflateEnd(&stream);
1063        if ((st != Z_STREAM_END) || stream.total_out != size) {
1064                free(buffer);
1065                return NULL;
1066        }
1067
1068        return buffer;
1069}
1070
1071static void *unpack_delta_entry(unsigned char *base_sha1,
1072                                unsigned long delta_size,
1073                                unsigned long left,
1074                                char *type,
1075                                unsigned long *sizep,
1076                                struct packed_git *p)
1077{
1078        struct pack_entry base_ent;
1079        void *delta_data, *result, *base;
1080        unsigned long result_size, base_size;
1081
1082        if (left < 20)
1083                die("truncated pack file");
1084
1085        /* The base entry _must_ be in the same pack */
1086        if (!find_pack_entry_one(base_sha1, &base_ent, p))
1087                die("failed to find delta-pack base object %s",
1088                    sha1_to_hex(base_sha1));
1089        base = unpack_entry_gently(&base_ent, type, &base_size);
1090        if (!base)
1091                die("failed to read delta-pack base object %s",
1092                    sha1_to_hex(base_sha1));
1093
1094        delta_data = unpack_compressed_entry(base_sha1 + 20,
1095                             delta_size, left - 20);
1096        result = patch_delta(base, base_size,
1097                             delta_data, delta_size,
1098                             &result_size);
1099        if (!result)
1100                die("failed to apply delta");
1101        free(delta_data);
1102        free(base);
1103        *sizep = result_size;
1104        return result;
1105}
1106
1107static void *unpack_entry(struct pack_entry *entry,
1108                          char *type, unsigned long *sizep)
1109{
1110        struct packed_git *p = entry->p;
1111        void *retval;
1112
1113        if (use_packed_git(p))
1114                die("cannot map packed file");
1115        retval = unpack_entry_gently(entry, type, sizep);
1116        unuse_packed_git(p);
1117        if (!retval)
1118                die("corrupted pack file %s", p->pack_name);
1119        return retval;
1120}
1121
1122/* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1123void *unpack_entry_gently(struct pack_entry *entry,
1124                          char *type, unsigned long *sizep)
1125{
1126        struct packed_git *p = entry->p;
1127        unsigned long offset, size, left;
1128        unsigned char *pack;
1129        enum object_type kind;
1130
1131        offset = unpack_object_header(p, entry->offset, &kind, &size);
1132        pack = (unsigned char *) p->pack_base + offset;
1133        left = p->pack_size - offset;
1134        switch (kind) {
1135        case OBJ_DELTA:
1136                return unpack_delta_entry(pack, size, left, type, sizep, p);
1137        case OBJ_COMMIT:
1138        case OBJ_TREE:
1139        case OBJ_BLOB:
1140        case OBJ_TAG:
1141                strcpy(type, type_names[kind]);
1142                *sizep = size;
1143                return unpack_compressed_entry(pack, size, left);
1144        default:
1145                return NULL;
1146        }
1147}
1148
1149int num_packed_objects(const struct packed_git *p)
1150{
1151        /* See check_packed_git_idx() */
1152        return (p->index_size - 20 - 20 - 4*256) / 24;
1153}
1154
1155int nth_packed_object_sha1(const struct packed_git *p, int n,
1156                           unsigned char* sha1)
1157{
1158        void *index = p->index_base + 256;
1159        if (n < 0 || num_packed_objects(p) <= n)
1160                return -1;
1161        hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
1162        return 0;
1163}
1164
1165int find_pack_entry_one(const unsigned char *sha1,
1166                        struct pack_entry *e, struct packed_git *p)
1167{
1168        unsigned int *level1_ofs = p->index_base;
1169        int hi = ntohl(level1_ofs[*sha1]);
1170        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1171        void *index = p->index_base + 256;
1172
1173        do {
1174                int mi = (lo + hi) / 2;
1175                int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
1176                if (!cmp) {
1177                        e->offset = ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
1178                        hashcpy(e->sha1, sha1);
1179                        e->p = p;
1180                        return 1;
1181                }
1182                if (cmp > 0)
1183                        hi = mi;
1184                else
1185                        lo = mi+1;
1186        } while (lo < hi);
1187        return 0;
1188}
1189
1190static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1191{
1192        struct packed_git *p;
1193        prepare_packed_git();
1194
1195        for (p = packed_git; p; p = p->next) {
1196                if (find_pack_entry_one(sha1, e, p))
1197                        return 1;
1198        }
1199        return 0;
1200}
1201
1202struct packed_git *find_sha1_pack(const unsigned char *sha1, 
1203                                  struct packed_git *packs)
1204{
1205        struct packed_git *p;
1206        struct pack_entry e;
1207
1208        for (p = packs; p; p = p->next) {
1209                if (find_pack_entry_one(sha1, &e, p))
1210                        return p;
1211        }
1212        return NULL;
1213        
1214}
1215
1216int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1217{
1218        int status;
1219        unsigned long mapsize, size;
1220        void *map;
1221        z_stream stream;
1222        char hdr[128];
1223
1224        map = map_sha1_file(sha1, &mapsize);
1225        if (!map) {
1226                struct pack_entry e;
1227
1228                if (find_pack_entry(sha1, &e))
1229                        return packed_object_info(&e, type, sizep);
1230                reprepare_packed_git();
1231                if (find_pack_entry(sha1, &e))
1232                        return packed_object_info(&e, type, sizep);
1233                return error("unable to find %s", sha1_to_hex(sha1));
1234        }
1235        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1236                status = error("unable to unpack %s header",
1237                               sha1_to_hex(sha1));
1238        if (parse_sha1_header(hdr, type, &size) < 0)
1239                status = error("unable to parse %s header", sha1_to_hex(sha1));
1240        else {
1241                status = 0;
1242                if (sizep)
1243                        *sizep = size;
1244        }
1245        inflateEnd(&stream);
1246        munmap(map, mapsize);
1247        return status;
1248}
1249
1250static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1251{
1252        struct pack_entry e;
1253
1254        if (!find_pack_entry(sha1, &e)) {
1255                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1256                return NULL;
1257        }
1258        return unpack_entry(&e, type, size);
1259}
1260
1261void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1262{
1263        unsigned long mapsize;
1264        void *map, *buf;
1265        struct pack_entry e;
1266
1267        if (find_pack_entry(sha1, &e))
1268                return read_packed_sha1(sha1, type, size);
1269        map = map_sha1_file(sha1, &mapsize);
1270        if (map) {
1271                buf = unpack_sha1_file(map, mapsize, type, size);
1272                munmap(map, mapsize);
1273                return buf;
1274        }
1275        reprepare_packed_git();
1276        if (find_pack_entry(sha1, &e))
1277                return read_packed_sha1(sha1, type, size);
1278        return NULL;
1279}
1280
1281void *read_object_with_reference(const unsigned char *sha1,
1282                                 const char *required_type,
1283                                 unsigned long *size,
1284                                 unsigned char *actual_sha1_return)
1285{
1286        char type[20];
1287        void *buffer;
1288        unsigned long isize;
1289        unsigned char actual_sha1[20];
1290
1291        hashcpy(actual_sha1, sha1);
1292        while (1) {
1293                int ref_length = -1;
1294                const char *ref_type = NULL;
1295
1296                buffer = read_sha1_file(actual_sha1, type, &isize);
1297                if (!buffer)
1298                        return NULL;
1299                if (!strcmp(type, required_type)) {
1300                        *size = isize;
1301                        if (actual_sha1_return)
1302                                hashcpy(actual_sha1_return, actual_sha1);
1303                        return buffer;
1304                }
1305                /* Handle references */
1306                else if (!strcmp(type, commit_type))
1307                        ref_type = "tree ";
1308                else if (!strcmp(type, tag_type))
1309                        ref_type = "object ";
1310                else {
1311                        free(buffer);
1312                        return NULL;
1313                }
1314                ref_length = strlen(ref_type);
1315
1316                if (memcmp(buffer, ref_type, ref_length) ||
1317                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1318                        free(buffer);
1319                        return NULL;
1320                }
1321                free(buffer);
1322                /* Now we have the ID of the referred-to object in
1323                 * actual_sha1.  Check again. */
1324        }
1325}
1326
1327char *write_sha1_file_prepare(void *buf,
1328                              unsigned long len,
1329                              const char *type,
1330                              unsigned char *sha1,
1331                              unsigned char *hdr,
1332                              int *hdrlen)
1333{
1334        SHA_CTX c;
1335
1336        /* Generate the header */
1337        *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1338
1339        /* Sha1.. */
1340        SHA1_Init(&c);
1341        SHA1_Update(&c, hdr, *hdrlen);
1342        SHA1_Update(&c, buf, len);
1343        SHA1_Final(sha1, &c);
1344
1345        return sha1_file_name(sha1);
1346}
1347
1348/*
1349 * Link the tempfile to the final place, possibly creating the
1350 * last directory level as you do so.
1351 *
1352 * Returns the errno on failure, 0 on success.
1353 */
1354static int link_temp_to_file(const char *tmpfile, char *filename)
1355{
1356        int ret;
1357        char *dir;
1358
1359        if (!link(tmpfile, filename))
1360                return 0;
1361
1362        /*
1363         * Try to mkdir the last path component if that failed.
1364         *
1365         * Re-try the "link()" regardless of whether the mkdir
1366         * succeeds, since a race might mean that somebody
1367         * else succeeded.
1368         */
1369        ret = errno;
1370        dir = strrchr(filename, '/');
1371        if (dir) {
1372                *dir = 0;
1373                mkdir(filename, 0777);
1374                if (adjust_shared_perm(filename))
1375                        return -2;
1376                *dir = '/';
1377                if (!link(tmpfile, filename))
1378                        return 0;
1379                ret = errno;
1380        }
1381        return ret;
1382}
1383
1384/*
1385 * Move the just written object into its final resting place
1386 */
1387int move_temp_to_file(const char *tmpfile, char *filename)
1388{
1389        int ret = link_temp_to_file(tmpfile, filename);
1390
1391        /*
1392         * Coda hack - coda doesn't like cross-directory links,
1393         * so we fall back to a rename, which will mean that it
1394         * won't be able to check collisions, but that's not a
1395         * big deal.
1396         *
1397         * The same holds for FAT formatted media.
1398         *
1399         * When this succeeds, we just return 0. We have nothing
1400         * left to unlink.
1401         */
1402        if (ret && ret != EEXIST) {
1403                if (!rename(tmpfile, filename))
1404                        return 0;
1405                ret = errno;
1406        }
1407        unlink(tmpfile);
1408        if (ret) {
1409                if (ret != EEXIST) {
1410                        fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1411                        return -1;
1412                }
1413                /* FIXME!!! Collision check here ? */
1414        }
1415
1416        return 0;
1417}
1418
1419static int write_buffer(int fd, const void *buf, size_t len)
1420{
1421        while (len) {
1422                ssize_t size;
1423
1424                size = write(fd, buf, len);
1425                if (!size)
1426                        return error("file write: disk full");
1427                if (size < 0) {
1428                        if (errno == EINTR || errno == EAGAIN)
1429                                continue;
1430                        return error("file write error (%s)", strerror(errno));
1431                }
1432                len -= size;
1433                buf = (char *) buf + size;
1434        }
1435        return 0;
1436}
1437
1438static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1439{
1440        int hdr_len;
1441        unsigned char c;
1442
1443        c = (type << 4) | (len & 15);
1444        len >>= 4;
1445        hdr_len = 1;
1446        while (len) {
1447                *hdr++ = c | 0x80;
1448                hdr_len++;
1449                c = (len & 0x7f);
1450                len >>= 7;
1451        }
1452        *hdr = c;
1453        return hdr_len;
1454}
1455
1456static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1457{
1458        int obj_type, hdr;
1459
1460        if (use_legacy_headers) {
1461                while (deflate(stream, 0) == Z_OK)
1462                        /* nothing */;
1463                return;
1464        }
1465        if (!strcmp(type, blob_type))
1466                obj_type = OBJ_BLOB;
1467        else if (!strcmp(type, tree_type))
1468                obj_type = OBJ_TREE;
1469        else if (!strcmp(type, commit_type))
1470                obj_type = OBJ_COMMIT;
1471        else if (!strcmp(type, tag_type))
1472                obj_type = OBJ_TAG;
1473        else
1474                die("trying to generate bogus object of type '%s'", type);
1475        hdr = write_binary_header(stream->next_out, obj_type, len);
1476        stream->total_out = hdr;
1477        stream->next_out += hdr;
1478        stream->avail_out -= hdr;
1479}
1480
1481int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1482{
1483        int size;
1484        unsigned char *compressed;
1485        z_stream stream;
1486        unsigned char sha1[20];
1487        char *filename;
1488        static char tmpfile[PATH_MAX];
1489        unsigned char hdr[50];
1490        int fd, hdrlen;
1491
1492        /* Normally if we have it in the pack then we do not bother writing
1493         * it out into .git/objects/??/?{38} file.
1494         */
1495        filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1496        if (returnsha1)
1497                hashcpy(returnsha1, sha1);
1498        if (has_sha1_file(sha1))
1499                return 0;
1500        fd = open(filename, O_RDONLY);
1501        if (fd >= 0) {
1502                /*
1503                 * FIXME!!! We might do collision checking here, but we'd
1504                 * need to uncompress the old file and check it. Later.
1505                 */
1506                close(fd);
1507                return 0;
1508        }
1509
1510        if (errno != ENOENT) {
1511                fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1512                return -1;
1513        }
1514
1515        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1516
1517        fd = mkstemp(tmpfile);
1518        if (fd < 0) {
1519                fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1520                return -1;
1521        }
1522
1523        /* Set it up */
1524        memset(&stream, 0, sizeof(stream));
1525        deflateInit(&stream, zlib_compression_level);
1526        size = 8 + deflateBound(&stream, len+hdrlen);
1527        compressed = xmalloc(size);
1528
1529        /* Compress it */
1530        stream.next_out = compressed;
1531        stream.avail_out = size;
1532
1533        /* First header.. */
1534        stream.next_in = hdr;
1535        stream.avail_in = hdrlen;
1536        setup_object_header(&stream, type, len);
1537
1538        /* Then the data itself.. */
1539        stream.next_in = buf;
1540        stream.avail_in = len;
1541        while (deflate(&stream, Z_FINISH) == Z_OK)
1542                /* nothing */;
1543        deflateEnd(&stream);
1544        size = stream.total_out;
1545
1546        if (write_buffer(fd, compressed, size) < 0)
1547                die("unable to write sha1 file");
1548        fchmod(fd, 0444);
1549        close(fd);
1550        free(compressed);
1551
1552        return move_temp_to_file(tmpfile, filename);
1553}
1554
1555/*
1556 * We need to unpack and recompress the object for writing
1557 * it out to a different file.
1558 */
1559static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1560{
1561        size_t size;
1562        z_stream stream;
1563        unsigned char *unpacked;
1564        unsigned long len;
1565        char type[20];
1566        char hdr[50];
1567        int hdrlen;
1568        void *buf;
1569
1570        /* need to unpack and recompress it by itself */
1571        unpacked = read_packed_sha1(sha1, type, &len);
1572
1573        hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1574
1575        /* Set it up */
1576        memset(&stream, 0, sizeof(stream));
1577        deflateInit(&stream, zlib_compression_level);
1578        size = deflateBound(&stream, len + hdrlen);
1579        buf = xmalloc(size);
1580
1581        /* Compress it */
1582        stream.next_out = buf;
1583        stream.avail_out = size;
1584
1585        /* First header.. */
1586        stream.next_in = (void *)hdr;
1587        stream.avail_in = hdrlen;
1588        while (deflate(&stream, 0) == Z_OK)
1589                /* nothing */;
1590
1591        /* Then the data itself.. */
1592        stream.next_in = unpacked;
1593        stream.avail_in = len;
1594        while (deflate(&stream, Z_FINISH) == Z_OK)
1595                /* nothing */;
1596        deflateEnd(&stream);
1597        free(unpacked);
1598
1599        *objsize = stream.total_out;
1600        return buf;
1601}
1602
1603int write_sha1_to_fd(int fd, const unsigned char *sha1)
1604{
1605        int retval;
1606        unsigned long objsize;
1607        void *buf = map_sha1_file(sha1, &objsize);
1608
1609        if (buf) {
1610                retval = write_buffer(fd, buf, objsize);
1611                munmap(buf, objsize);
1612                return retval;
1613        }
1614
1615        buf = repack_object(sha1, &objsize);
1616        retval = write_buffer(fd, buf, objsize);
1617        free(buf);
1618        return retval;
1619}
1620
1621int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1622                       size_t bufsize, size_t *bufposn)
1623{
1624        char tmpfile[PATH_MAX];
1625        int local;
1626        z_stream stream;
1627        unsigned char real_sha1[20];
1628        unsigned char discard[4096];
1629        int ret;
1630        SHA_CTX c;
1631
1632        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1633
1634        local = mkstemp(tmpfile);
1635        if (local < 0)
1636                return error("Couldn't open %s for %s",
1637                             tmpfile, sha1_to_hex(sha1));
1638
1639        memset(&stream, 0, sizeof(stream));
1640
1641        inflateInit(&stream);
1642
1643        SHA1_Init(&c);
1644
1645        do {
1646                ssize_t size;
1647                if (*bufposn) {
1648                        stream.avail_in = *bufposn;
1649                        stream.next_in = (unsigned char *) buffer;
1650                        do {
1651                                stream.next_out = discard;
1652                                stream.avail_out = sizeof(discard);
1653                                ret = inflate(&stream, Z_SYNC_FLUSH);
1654                                SHA1_Update(&c, discard, sizeof(discard) -
1655                                            stream.avail_out);
1656                        } while (stream.avail_in && ret == Z_OK);
1657                        if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1658                                die("unable to write sha1 file");
1659                        memmove(buffer, buffer + *bufposn - stream.avail_in,
1660                                stream.avail_in);
1661                        *bufposn = stream.avail_in;
1662                        if (ret != Z_OK)
1663                                break;
1664                }
1665                size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1666                if (size <= 0) {
1667                        close(local);
1668                        unlink(tmpfile);
1669                        if (!size)
1670                                return error("Connection closed?");
1671                        perror("Reading from connection");
1672                        return -1;
1673                }
1674                *bufposn += size;
1675        } while (1);
1676        inflateEnd(&stream);
1677
1678        close(local);
1679        SHA1_Final(real_sha1, &c);
1680        if (ret != Z_STREAM_END) {
1681                unlink(tmpfile);
1682                return error("File %s corrupted", sha1_to_hex(sha1));
1683        }
1684        if (hashcmp(sha1, real_sha1)) {
1685                unlink(tmpfile);
1686                return error("File %s has bad hash", sha1_to_hex(sha1));
1687        }
1688
1689        return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1690}
1691
1692int has_pack_index(const unsigned char *sha1)
1693{
1694        struct stat st;
1695        if (stat(sha1_pack_index_name(sha1), &st))
1696                return 0;
1697        return 1;
1698}
1699
1700int has_pack_file(const unsigned char *sha1)
1701{
1702        struct stat st;
1703        if (stat(sha1_pack_name(sha1), &st))
1704                return 0;
1705        return 1;
1706}
1707
1708int has_sha1_pack(const unsigned char *sha1)
1709{
1710        struct pack_entry e;
1711        return find_pack_entry(sha1, &e);
1712}
1713
1714int has_sha1_file(const unsigned char *sha1)
1715{
1716        struct stat st;
1717        struct pack_entry e;
1718
1719        if (find_pack_entry(sha1, &e))
1720                return 1;
1721        return find_sha1_file(sha1, &st) ? 1 : 0;
1722}
1723
1724/*
1725 * reads from fd as long as possible into a supplied buffer of size bytes.
1726 * If necessary the buffer's size is increased using realloc()
1727 *
1728 * returns 0 if anything went fine and -1 otherwise
1729 *
1730 * NOTE: both buf and size may change, but even when -1 is returned
1731 * you still have to free() it yourself.
1732 */
1733int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1734{
1735        char* buf = *return_buf;
1736        unsigned long size = *return_size;
1737        int iret;
1738        unsigned long off = 0;
1739
1740        do {
1741                iret = xread(fd, buf + off, size - off);
1742                if (iret > 0) {
1743                        off += iret;
1744                        if (off == size) {
1745                                size *= 2;
1746                                buf = realloc(buf, size);
1747                        }
1748                }
1749        } while (iret > 0);
1750
1751        *return_buf = buf;
1752        *return_size = off;
1753
1754        if (iret < 0)
1755                return -1;
1756        return 0;
1757}
1758
1759int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1760{
1761        unsigned long size = 4096;
1762        char *buf = malloc(size);
1763        int ret;
1764        unsigned char hdr[50];
1765        int hdrlen;
1766
1767        if (read_pipe(fd, &buf, &size)) {
1768                free(buf);
1769                return -1;
1770        }
1771
1772        if (!type)
1773                type = blob_type;
1774        if (write_object)
1775                ret = write_sha1_file(buf, size, type, sha1);
1776        else {
1777                write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1778                ret = 0;
1779        }
1780        free(buf);
1781        return ret;
1782}
1783
1784int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1785{
1786        unsigned long size = st->st_size;
1787        void *buf;
1788        int ret;
1789        unsigned char hdr[50];
1790        int hdrlen;
1791
1792        buf = "";
1793        if (size)
1794                buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1795        close(fd);
1796        if (buf == MAP_FAILED)
1797                return -1;
1798
1799        if (!type)
1800                type = blob_type;
1801        if (write_object)
1802                ret = write_sha1_file(buf, size, type, sha1);
1803        else {
1804                write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1805                ret = 0;
1806        }
1807        if (size)
1808                munmap(buf, size);
1809        return ret;
1810}
1811
1812int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1813{
1814        int fd;
1815        char *target;
1816
1817        switch (st->st_mode & S_IFMT) {
1818        case S_IFREG:
1819                fd = open(path, O_RDONLY);
1820                if (fd < 0)
1821                        return error("open(\"%s\"): %s", path,
1822                                     strerror(errno));
1823                if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1824                        return error("%s: failed to insert into database",
1825                                     path);
1826                break;
1827        case S_IFLNK:
1828                target = xmalloc(st->st_size+1);
1829                if (readlink(path, target, st->st_size+1) != st->st_size) {
1830                        char *errstr = strerror(errno);
1831                        free(target);
1832                        return error("readlink(\"%s\"): %s", path,
1833                                     errstr);
1834                }
1835                if (!write_object) {
1836                        unsigned char hdr[50];
1837                        int hdrlen;
1838                        write_sha1_file_prepare(target, st->st_size, blob_type,
1839                                                sha1, hdr, &hdrlen);
1840                } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1841                        return error("%s: failed to insert into database",
1842                                     path);
1843                free(target);
1844                break;
1845        default:
1846                return error("%s: unsupported file type", path);
1847        }
1848        return 0;
1849}