sha1_file.con commit Merge fixes early for next maint series. (a68de95)
   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
  13#ifndef O_NOATIME
  14#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  15#define O_NOATIME 01000000
  16#else
  17#define O_NOATIME 0
  18#endif
  19#endif
  20
  21const unsigned char null_sha1[20] = { 0, };
  22
  23static unsigned int sha1_file_open_flag = O_NOATIME;
  24
  25static unsigned hexval(char c)
  26{
  27        if (c >= '0' && c <= '9')
  28                return c - '0';
  29        if (c >= 'a' && c <= 'f')
  30                return c - 'a' + 10;
  31        if (c >= 'A' && c <= 'F')
  32                return c - 'A' + 10;
  33        return ~0;
  34}
  35
  36int get_sha1_hex(const char *hex, unsigned char *sha1)
  37{
  38        int i;
  39        for (i = 0; i < 20; i++) {
  40                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  41                if (val & ~0xff)
  42                        return -1;
  43                *sha1++ = val;
  44                hex += 2;
  45        }
  46        return 0;
  47}
  48
  49int adjust_shared_perm(const char *path)
  50{
  51        struct stat st;
  52        int mode;
  53
  54        if (!shared_repository)
  55                return 0;
  56        if (lstat(path, &st) < 0)
  57                return -1;
  58        mode = st.st_mode;
  59        if (mode & S_IRUSR)
  60                mode |= S_IRGRP;
  61        if (mode & S_IWUSR)
  62                mode |= S_IWGRP;
  63        if (mode & S_IXUSR)
  64                mode |= S_IXGRP;
  65        if (S_ISDIR(mode))
  66                mode |= S_ISGID;
  67        if (chmod(path, mode) < 0)
  68                return -2;
  69        return 0;
  70}
  71
  72int safe_create_leading_directories(char *path)
  73{
  74        char *pos = path;
  75        struct stat st;
  76
  77        if (*pos == '/')
  78                pos++;
  79
  80        while (pos) {
  81                pos = strchr(pos, '/');
  82                if (!pos)
  83                        break;
  84                *pos = 0;
  85                if (!stat(path, &st)) {
  86                        /* path exists */
  87                        if (!S_ISDIR(st.st_mode)) {
  88                                *pos = '/';
  89                                return -3;
  90                        }
  91                }
  92                else if (mkdir(path, 0777)) {
  93                        *pos = '/';
  94                        return -1;
  95                }
  96                else if (adjust_shared_perm(path)) {
  97                        *pos = '/';
  98                        return -2;
  99                }
 100                *pos++ = '/';
 101        }
 102        return 0;
 103}
 104
 105char * sha1_to_hex(const unsigned char *sha1)
 106{
 107        static char buffer[50];
 108        static const char hex[] = "0123456789abcdef";
 109        char *buf = buffer;
 110        int i;
 111
 112        for (i = 0; i < 20; i++) {
 113                unsigned int val = *sha1++;
 114                *buf++ = hex[val >> 4];
 115                *buf++ = hex[val & 0xf];
 116        }
 117        *buf = '\0';
 118
 119        return buffer;
 120}
 121
 122static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 123{
 124        int i;
 125        for (i = 0; i < 20; i++) {
 126                static char hex[] = "0123456789abcdef";
 127                unsigned int val = sha1[i];
 128                char *pos = pathbuf + i*2 + (i > 0);
 129                *pos++ = hex[val >> 4];
 130                *pos = hex[val & 0xf];
 131        }
 132}
 133
 134/*
 135 * NOTE! This returns a statically allocated buffer, so you have to be
 136 * careful about using it. Do a "strdup()" if you need to save the
 137 * filename.
 138 *
 139 * Also note that this returns the location for creating.  Reading
 140 * SHA1 file can happen from any alternate directory listed in the
 141 * DB_ENVIRONMENT environment variable if it is not found in
 142 * the primary object database.
 143 */
 144char *sha1_file_name(const unsigned char *sha1)
 145{
 146        static char *name, *base;
 147
 148        if (!base) {
 149                const char *sha1_file_directory = get_object_directory();
 150                int len = strlen(sha1_file_directory);
 151                base = xmalloc(len + 60);
 152                memcpy(base, sha1_file_directory, len);
 153                memset(base+len, 0, 60);
 154                base[len] = '/';
 155                base[len+3] = '/';
 156                name = base + len + 1;
 157        }
 158        fill_sha1_path(name, sha1);
 159        return base;
 160}
 161
 162char *sha1_pack_name(const unsigned char *sha1)
 163{
 164        static const char hex[] = "0123456789abcdef";
 165        static char *name, *base, *buf;
 166        int i;
 167
 168        if (!base) {
 169                const char *sha1_file_directory = get_object_directory();
 170                int len = strlen(sha1_file_directory);
 171                base = xmalloc(len + 60);
 172                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 173                name = base + len + 11;
 174        }
 175
 176        buf = name;
 177
 178        for (i = 0; i < 20; i++) {
 179                unsigned int val = *sha1++;
 180                *buf++ = hex[val >> 4];
 181                *buf++ = hex[val & 0xf];
 182        }
 183        
 184        return base;
 185}
 186
 187char *sha1_pack_index_name(const unsigned char *sha1)
 188{
 189        static const char hex[] = "0123456789abcdef";
 190        static char *name, *base, *buf;
 191        int i;
 192
 193        if (!base) {
 194                const char *sha1_file_directory = get_object_directory();
 195                int len = strlen(sha1_file_directory);
 196                base = xmalloc(len + 60);
 197                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 198                name = base + len + 11;
 199        }
 200
 201        buf = name;
 202
 203        for (i = 0; i < 20; i++) {
 204                unsigned int val = *sha1++;
 205                *buf++ = hex[val >> 4];
 206                *buf++ = hex[val & 0xf];
 207        }
 208        
 209        return base;
 210}
 211
 212struct alternate_object_database *alt_odb_list;
 213static struct alternate_object_database **alt_odb_tail;
 214
 215/*
 216 * Prepare alternate object database registry.
 217 *
 218 * The variable alt_odb_list points at the list of struct
 219 * alternate_object_database.  The elements on this list come from
 220 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 221 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 222 * whose contents is similar to that environment variable but can be
 223 * LF separated.  Its base points at a statically allocated buffer that
 224 * contains "/the/directory/corresponding/to/.git/objects/...", while
 225 * its name points just after the slash at the end of ".git/objects/"
 226 * in the example above, and has enough space to hold 40-byte hex
 227 * SHA1, an extra slash for the first level indirection, and the
 228 * terminating NUL.
 229 */
 230static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 231                                 const char *relative_base)
 232{
 233        const char *cp, *last;
 234        struct alternate_object_database *ent;
 235        const char *objdir = get_object_directory();
 236        int base_len = -1;
 237
 238        last = alt;
 239        while (last < ep) {
 240                cp = last;
 241                if (cp < ep && *cp == '#') {
 242                        while (cp < ep && *cp != sep)
 243                                cp++;
 244                        last = cp + 1;
 245                        continue;
 246                }
 247                for ( ; cp < ep && *cp != sep; cp++)
 248                        ;
 249                if (last != cp) {
 250                        struct stat st;
 251                        struct alternate_object_database *alt;
 252                        /* 43 = 40-byte + 2 '/' + terminating NUL */
 253                        int pfxlen = cp - last;
 254                        int entlen = pfxlen + 43;
 255
 256                        if (*last != '/' && relative_base) {
 257                                /* Relative alt-odb */
 258                                if (base_len < 0)
 259                                        base_len = strlen(relative_base) + 1;
 260                                entlen += base_len;
 261                                pfxlen += base_len;
 262                        }
 263                        ent = xmalloc(sizeof(*ent) + entlen);
 264
 265                        if (*last != '/' && relative_base) {
 266                                memcpy(ent->base, relative_base, base_len - 1);
 267                                ent->base[base_len - 1] = '/';
 268                                memcpy(ent->base + base_len,
 269                                       last, cp - last);
 270                        }
 271                        else
 272                                memcpy(ent->base, last, pfxlen);
 273
 274                        ent->name = ent->base + pfxlen + 1;
 275                        ent->base[pfxlen + 3] = '/';
 276                        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 277
 278                        /* Detect cases where alternate disappeared */
 279                        if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 280                                error("object directory %s does not exist; "
 281                                      "check .git/objects/info/alternates.",
 282                                      ent->base);
 283                                goto bad;
 284                        }
 285                        ent->base[pfxlen] = '/';
 286
 287                        /* Prevent the common mistake of listing the same
 288                         * thing twice, or object directory itself.
 289                         */
 290                        for (alt = alt_odb_list; alt; alt = alt->next)
 291                                if (!memcmp(ent->base, alt->base, pfxlen))
 292                                        goto bad;
 293                        if (!memcmp(ent->base, objdir, pfxlen)) {
 294                        bad:
 295                                free(ent);
 296                        }
 297                        else {
 298                                *alt_odb_tail = ent;
 299                                alt_odb_tail = &(ent->next);
 300                                ent->next = NULL;
 301                        }
 302                }
 303                while (cp < ep && *cp == sep)
 304                        cp++;
 305                last = cp;
 306        }
 307}
 308
 309void prepare_alt_odb(void)
 310{
 311        char path[PATH_MAX];
 312        char *map;
 313        int fd;
 314        struct stat st;
 315        char *alt;
 316
 317        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 318        if (!alt) alt = "";
 319
 320        if (alt_odb_tail)
 321                return;
 322        alt_odb_tail = &alt_odb_list;
 323        link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 324
 325        sprintf(path, "%s/info/alternates", get_object_directory());
 326        fd = open(path, O_RDONLY);
 327        if (fd < 0)
 328                return;
 329        if (fstat(fd, &st) || (st.st_size == 0)) {
 330                close(fd);
 331                return;
 332        }
 333        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 334        close(fd);
 335        if (map == MAP_FAILED)
 336                return;
 337
 338        link_alt_odb_entries(map, map + st.st_size, '\n',
 339                             get_object_directory());
 340        munmap(map, st.st_size);
 341}
 342
 343static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 344{
 345        char *name = sha1_file_name(sha1);
 346        struct alternate_object_database *alt;
 347
 348        if (!stat(name, st))
 349                return name;
 350        prepare_alt_odb();
 351        for (alt = alt_odb_list; alt; alt = alt->next) {
 352                name = alt->name;
 353                fill_sha1_path(name, sha1);
 354                if (!stat(alt->base, st))
 355                        return alt->base;
 356        }
 357        return NULL;
 358}
 359
 360#define PACK_MAX_SZ (1<<26)
 361static int pack_used_ctr;
 362static unsigned long pack_mapped;
 363struct packed_git *packed_git;
 364
 365static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 366                                void **idx_map_)
 367{
 368        void *idx_map;
 369        unsigned int *index;
 370        unsigned long idx_size;
 371        int nr, i;
 372        int fd = open(path, O_RDONLY);
 373        struct stat st;
 374        if (fd < 0)
 375                return -1;
 376        if (fstat(fd, &st)) {
 377                close(fd);
 378                return -1;
 379        }
 380        idx_size = st.st_size;
 381        idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 382        close(fd);
 383        if (idx_map == MAP_FAILED)
 384                return -1;
 385
 386        index = idx_map;
 387        *idx_map_ = idx_map;
 388        *idx_size_ = idx_size;
 389
 390        /* check index map */
 391        if (idx_size < 4*256 + 20 + 20)
 392                return error("index file too small");
 393        nr = 0;
 394        for (i = 0; i < 256; i++) {
 395                unsigned int n = ntohl(index[i]);
 396                if (n < nr)
 397                        return error("non-monotonic index");
 398                nr = n;
 399        }
 400
 401        /*
 402         * Total size:
 403         *  - 256 index entries 4 bytes each
 404         *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 405         *  - 20-byte SHA1 of the packfile
 406         *  - 20-byte SHA1 file checksum
 407         */
 408        if (idx_size != 4*256 + nr * 24 + 20 + 20)
 409                return error("wrong index file size");
 410
 411        return 0;
 412}
 413
 414static int unuse_one_packed_git(void)
 415{
 416        struct packed_git *p, *lru = NULL;
 417
 418        for (p = packed_git; p; p = p->next) {
 419                if (p->pack_use_cnt || !p->pack_base)
 420                        continue;
 421                if (!lru || p->pack_last_used < lru->pack_last_used)
 422                        lru = p;
 423        }
 424        if (!lru)
 425                return 0;
 426        munmap(lru->pack_base, lru->pack_size);
 427        lru->pack_base = NULL;
 428        return 1;
 429}
 430
 431void unuse_packed_git(struct packed_git *p)
 432{
 433        p->pack_use_cnt--;
 434}
 435
 436int use_packed_git(struct packed_git *p)
 437{
 438        if (!p->pack_size) {
 439                struct stat st;
 440                // We created the struct before we had the pack
 441                stat(p->pack_name, &st);
 442                if (!S_ISREG(st.st_mode))
 443                        die("packfile %s not a regular file", p->pack_name);
 444                p->pack_size = st.st_size;
 445        }
 446        if (!p->pack_base) {
 447                int fd;
 448                struct stat st;
 449                void *map;
 450
 451                pack_mapped += p->pack_size;
 452                while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 453                        ; /* nothing */
 454                fd = open(p->pack_name, O_RDONLY);
 455                if (fd < 0)
 456                        die("packfile %s cannot be opened", p->pack_name);
 457                if (fstat(fd, &st)) {
 458                        close(fd);
 459                        die("packfile %s cannot be opened", p->pack_name);
 460                }
 461                if (st.st_size != p->pack_size)
 462                        die("packfile %s size mismatch.", p->pack_name);
 463                map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 464                close(fd);
 465                if (map == MAP_FAILED)
 466                        die("packfile %s cannot be mapped.", p->pack_name);
 467                p->pack_base = map;
 468
 469                /* Check if the pack file matches with the index file.
 470                 * this is cheap.
 471                 */
 472                if (memcmp((char*)(p->index_base) + p->index_size - 40,
 473                           p->pack_base + p->pack_size - 20, 20)) {
 474                              
 475                        die("packfile %s does not match index.", p->pack_name);
 476                }
 477        }
 478        p->pack_last_used = pack_used_ctr++;
 479        p->pack_use_cnt++;
 480        return 0;
 481}
 482
 483struct packed_git *add_packed_git(char *path, int path_len, int local)
 484{
 485        struct stat st;
 486        struct packed_git *p;
 487        unsigned long idx_size;
 488        void *idx_map;
 489        unsigned char sha1[20];
 490
 491        if (check_packed_git_idx(path, &idx_size, &idx_map))
 492                return NULL;
 493
 494        /* do we have a corresponding .pack file? */
 495        strcpy(path + path_len - 4, ".pack");
 496        if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 497                munmap(idx_map, idx_size);
 498                return NULL;
 499        }
 500        /* ok, it looks sane as far as we can check without
 501         * actually mapping the pack file.
 502         */
 503        p = xmalloc(sizeof(*p) + path_len + 2);
 504        strcpy(p->pack_name, path);
 505        p->index_size = idx_size;
 506        p->pack_size = st.st_size;
 507        p->index_base = idx_map;
 508        p->next = NULL;
 509        p->pack_base = NULL;
 510        p->pack_last_used = 0;
 511        p->pack_use_cnt = 0;
 512        p->pack_local = local;
 513        if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 514                memcpy(p->sha1, sha1, 20);
 515        return p;
 516}
 517
 518struct packed_git *parse_pack_index(unsigned char *sha1)
 519{
 520        char *path = sha1_pack_index_name(sha1);
 521        return parse_pack_index_file(sha1, path);
 522}
 523
 524struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 525{
 526        struct packed_git *p;
 527        unsigned long idx_size;
 528        void *idx_map;
 529        char *path;
 530
 531        if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 532                return NULL;
 533
 534        path = sha1_pack_name(sha1);
 535
 536        p = xmalloc(sizeof(*p) + strlen(path) + 2);
 537        strcpy(p->pack_name, path);
 538        p->index_size = idx_size;
 539        p->pack_size = 0;
 540        p->index_base = idx_map;
 541        p->next = NULL;
 542        p->pack_base = NULL;
 543        p->pack_last_used = 0;
 544        p->pack_use_cnt = 0;
 545        memcpy(p->sha1, sha1, 20);
 546        return p;
 547}
 548
 549void install_packed_git(struct packed_git *pack)
 550{
 551        pack->next = packed_git;
 552        packed_git = pack;
 553}
 554
 555static void prepare_packed_git_one(char *objdir, int local)
 556{
 557        char path[PATH_MAX];
 558        int len;
 559        DIR *dir;
 560        struct dirent *de;
 561
 562        sprintf(path, "%s/pack", objdir);
 563        len = strlen(path);
 564        dir = opendir(path);
 565        if (!dir) {
 566                if (errno != ENOENT)
 567                        error("unable to open object pack directory: %s: %s",
 568                              path, strerror(errno));
 569                return;
 570        }
 571        path[len++] = '/';
 572        while ((de = readdir(dir)) != NULL) {
 573                int namelen = strlen(de->d_name);
 574                struct packed_git *p;
 575
 576                if (strcmp(de->d_name + namelen - 4, ".idx"))
 577                        continue;
 578
 579                /* we have .idx.  Is it a file we can map? */
 580                strcpy(path + len, de->d_name);
 581                p = add_packed_git(path, len + namelen, local);
 582                if (!p)
 583                        continue;
 584                p->next = packed_git;
 585                packed_git = p;
 586        }
 587        closedir(dir);
 588}
 589
 590void prepare_packed_git(void)
 591{
 592        static int run_once = 0;
 593        struct alternate_object_database *alt;
 594
 595        if (run_once)
 596                return;
 597        prepare_packed_git_one(get_object_directory(), 1);
 598        prepare_alt_odb();
 599        for (alt = alt_odb_list; alt; alt = alt->next) {
 600                alt->name[-1] = 0;
 601                prepare_packed_git_one(alt->base, 0);
 602                alt->name[-1] = '/';
 603        }
 604        run_once = 1;
 605}
 606
 607int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 608{
 609        char header[100];
 610        unsigned char real_sha1[20];
 611        SHA_CTX c;
 612
 613        SHA1_Init(&c);
 614        SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 615        SHA1_Update(&c, map, size);
 616        SHA1_Final(real_sha1, &c);
 617        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 618}
 619
 620static void *map_sha1_file_internal(const unsigned char *sha1,
 621                                    unsigned long *size)
 622{
 623        struct stat st;
 624        void *map;
 625        int fd;
 626        char *filename = find_sha1_file(sha1, &st);
 627
 628        if (!filename) {
 629                return NULL;
 630        }
 631
 632        fd = open(filename, O_RDONLY | sha1_file_open_flag);
 633        if (fd < 0) {
 634                /* See if it works without O_NOATIME */
 635                switch (sha1_file_open_flag) {
 636                default:
 637                        fd = open(filename, O_RDONLY);
 638                        if (fd >= 0)
 639                                break;
 640                /* Fallthrough */
 641                case 0:
 642                        return NULL;
 643                }
 644
 645                /* If it failed once, it will probably fail again.
 646                 * Stop using O_NOATIME
 647                 */
 648                sha1_file_open_flag = 0;
 649        }
 650        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 651        close(fd);
 652        if (map == MAP_FAILED)
 653                return NULL;
 654        *size = st.st_size;
 655        return map;
 656}
 657
 658int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 659{
 660        /* Get the data stream */
 661        memset(stream, 0, sizeof(*stream));
 662        stream->next_in = map;
 663        stream->avail_in = mapsize;
 664        stream->next_out = buffer;
 665        stream->avail_out = size;
 666
 667        inflateInit(stream);
 668        return inflate(stream, 0);
 669}
 670
 671static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 672{
 673        int bytes = strlen(buffer) + 1;
 674        unsigned char *buf = xmalloc(1+size);
 675
 676        memcpy(buf, buffer + bytes, stream->total_out - bytes);
 677        bytes = stream->total_out - bytes;
 678        if (bytes < size) {
 679                stream->next_out = buf + bytes;
 680                stream->avail_out = size - bytes;
 681                while (inflate(stream, Z_FINISH) == Z_OK)
 682                        /* nothing */;
 683        }
 684        buf[size] = 0;
 685        inflateEnd(stream);
 686        return buf;
 687}
 688
 689/*
 690 * We used to just use "sscanf()", but that's actually way
 691 * too permissive for what we want to check. So do an anal
 692 * object header parse by hand.
 693 */
 694int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 695{
 696        int i;
 697        unsigned long size;
 698
 699        /*
 700         * The type can be at most ten bytes (including the 
 701         * terminating '\0' that we add), and is followed by
 702         * a space. 
 703         */
 704        i = 10;
 705        for (;;) {
 706                char c = *hdr++;
 707                if (c == ' ')
 708                        break;
 709                if (!--i)
 710                        return -1;
 711                *type++ = c;
 712        }
 713        *type = 0;
 714
 715        /*
 716         * The length must follow immediately, and be in canonical
 717         * decimal format (ie "010" is not valid).
 718         */
 719        size = *hdr++ - '0';
 720        if (size > 9)
 721                return -1;
 722        if (size) {
 723                for (;;) {
 724                        unsigned long c = *hdr - '0';
 725                        if (c > 9)
 726                                break;
 727                        hdr++;
 728                        size = size * 10 + c;
 729                }
 730        }
 731        *sizep = size;
 732
 733        /*
 734         * The length must be followed by a zero byte
 735         */
 736        return *hdr ? -1 : 0;
 737}
 738
 739void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 740{
 741        int ret;
 742        z_stream stream;
 743        char hdr[8192];
 744
 745        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 746        if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 747                return NULL;
 748
 749        return unpack_sha1_rest(&stream, hdr, *size);
 750}
 751
 752/* forward declaration for a mutually recursive function */
 753static int packed_object_info(struct pack_entry *entry,
 754                              char *type, unsigned long *sizep);
 755
 756static int packed_delta_info(unsigned char *base_sha1,
 757                             unsigned long delta_size,
 758                             unsigned long left,
 759                             char *type,
 760                             unsigned long *sizep,
 761                             struct packed_git *p)
 762{
 763        struct pack_entry base_ent;
 764
 765        if (left < 20)
 766                die("truncated pack file");
 767
 768        /* The base entry _must_ be in the same pack */
 769        if (!find_pack_entry_one(base_sha1, &base_ent, p))
 770                die("failed to find delta-pack base object %s",
 771                    sha1_to_hex(base_sha1));
 772
 773        /* We choose to only get the type of the base object and
 774         * ignore potentially corrupt pack file that expects the delta
 775         * based on a base with a wrong size.  This saves tons of
 776         * inflate() calls.
 777         */
 778
 779        if (packed_object_info(&base_ent, type, NULL))
 780                die("cannot get info for delta-pack base");
 781
 782        if (sizep) {
 783                const unsigned char *data;
 784                unsigned char delta_head[64];
 785                unsigned long result_size;
 786                z_stream stream;
 787                int st;
 788
 789                memset(&stream, 0, sizeof(stream));
 790
 791                data = stream.next_in = base_sha1 + 20;
 792                stream.avail_in = left - 20;
 793                stream.next_out = delta_head;
 794                stream.avail_out = sizeof(delta_head);
 795
 796                inflateInit(&stream);
 797                st = inflate(&stream, Z_FINISH);
 798                inflateEnd(&stream);
 799                if ((st != Z_STREAM_END) &&
 800                    stream.total_out != sizeof(delta_head))
 801                        die("delta data unpack-initial failed");
 802
 803                /* Examine the initial part of the delta to figure out
 804                 * the result size.
 805                 */
 806                data = delta_head;
 807                get_delta_hdr_size(&data); /* ignore base size */
 808
 809                /* Read the result size */
 810                result_size = get_delta_hdr_size(&data);
 811                *sizep = result_size;
 812        }
 813        return 0;
 814}
 815
 816static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 817        enum object_type *type, unsigned long *sizep)
 818{
 819        unsigned shift;
 820        unsigned char *pack, c;
 821        unsigned long size;
 822
 823        if (offset >= p->pack_size)
 824                die("object offset outside of pack file");
 825
 826        pack =  p->pack_base + offset;
 827        c = *pack++;
 828        offset++;
 829        *type = (c >> 4) & 7;
 830        size = c & 15;
 831        shift = 4;
 832        while (c & 0x80) {
 833                if (offset >= p->pack_size)
 834                        die("object offset outside of pack file");
 835                c = *pack++;
 836                offset++;
 837                size += (c & 0x7f) << shift;
 838                shift += 7;
 839        }
 840        *sizep = size;
 841        return offset;
 842}
 843
 844int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 845                           unsigned char *base, unsigned long *sizep,
 846                           enum object_type *kindp)
 847{
 848        unsigned long ptr;
 849        int status = -1;
 850
 851        use_packed_git(p);
 852        ptr = offset;
 853        ptr = unpack_object_header(p, ptr, kindp, sizep);
 854        if (*kindp != OBJ_DELTA)
 855                goto done;
 856        memcpy(base, p->pack_base + ptr, 20);
 857        status = 0;
 858 done:
 859        unuse_packed_git(p);
 860        return status;
 861}
 862
 863void packed_object_info_detail(struct pack_entry *e,
 864                               char *type,
 865                               unsigned long *size,
 866                               unsigned long *store_size,
 867                               unsigned int *delta_chain_length,
 868                               unsigned char *base_sha1)
 869{
 870        struct packed_git *p = e->p;
 871        unsigned long offset, left;
 872        unsigned char *pack;
 873        enum object_type kind;
 874
 875        offset = unpack_object_header(p, e->offset, &kind, size);
 876        pack = p->pack_base + offset;
 877        left = p->pack_size - offset;
 878        if (kind != OBJ_DELTA)
 879                *delta_chain_length = 0;
 880        else {
 881                unsigned int chain_length = 0;
 882                memcpy(base_sha1, pack, 20);
 883                do {
 884                        struct pack_entry base_ent;
 885                        unsigned long junk;
 886
 887                        find_pack_entry_one(pack, &base_ent, p);
 888                        offset = unpack_object_header(p, base_ent.offset,
 889                                                      &kind, &junk);
 890                        pack = p->pack_base + offset;
 891                        chain_length++;
 892                } while (kind == OBJ_DELTA);
 893                *delta_chain_length = chain_length;
 894        }
 895        switch (kind) {
 896        case OBJ_COMMIT:
 897                strcpy(type, "commit");
 898                break;
 899        case OBJ_TREE:
 900                strcpy(type, "tree");
 901                break;
 902        case OBJ_BLOB:
 903                strcpy(type, "blob");
 904                break;
 905        case OBJ_TAG:
 906                strcpy(type, "tag");
 907                break;
 908        default:
 909                die("corrupted pack file %s containing object of kind %d",
 910                    p->pack_name, kind);
 911        }
 912        *store_size = 0; /* notyet */
 913}
 914
 915static int packed_object_info(struct pack_entry *entry,
 916                              char *type, unsigned long *sizep)
 917{
 918        struct packed_git *p = entry->p;
 919        unsigned long offset, size, left;
 920        unsigned char *pack;
 921        enum object_type kind;
 922        int retval;
 923
 924        if (use_packed_git(p))
 925                die("cannot map packed file");
 926
 927        offset = unpack_object_header(p, entry->offset, &kind, &size);
 928        pack = p->pack_base + offset;
 929        left = p->pack_size - offset;
 930
 931        switch (kind) {
 932        case OBJ_DELTA:
 933                retval = packed_delta_info(pack, size, left, type, sizep, p);
 934                unuse_packed_git(p);
 935                return retval;
 936        case OBJ_COMMIT:
 937                strcpy(type, "commit");
 938                break;
 939        case OBJ_TREE:
 940                strcpy(type, "tree");
 941                break;
 942        case OBJ_BLOB:
 943                strcpy(type, "blob");
 944                break;
 945        case OBJ_TAG:
 946                strcpy(type, "tag");
 947                break;
 948        default:
 949                die("corrupted pack file %s containing object of kind %d",
 950                    p->pack_name, kind);
 951        }
 952        if (sizep)
 953                *sizep = size;
 954        unuse_packed_git(p);
 955        return 0;
 956}
 957
 958/* forward declaration for a mutually recursive function */
 959static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 960
 961static void *unpack_delta_entry(unsigned char *base_sha1,
 962                                unsigned long delta_size,
 963                                unsigned long left,
 964                                char *type,
 965                                unsigned long *sizep,
 966                                struct packed_git *p)
 967{
 968        struct pack_entry base_ent;
 969        void *data, *delta_data, *result, *base;
 970        unsigned long data_size, result_size, base_size;
 971        z_stream stream;
 972        int st;
 973
 974        if (left < 20)
 975                die("truncated pack file");
 976        data = base_sha1 + 20;
 977        data_size = left - 20;
 978        delta_data = xmalloc(delta_size);
 979
 980        memset(&stream, 0, sizeof(stream));
 981
 982        stream.next_in = data;
 983        stream.avail_in = data_size;
 984        stream.next_out = delta_data;
 985        stream.avail_out = delta_size;
 986
 987        inflateInit(&stream);
 988        st = inflate(&stream, Z_FINISH);
 989        inflateEnd(&stream);
 990        if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 991                die("delta data unpack failed");
 992
 993        /* The base entry _must_ be in the same pack */
 994        if (!find_pack_entry_one(base_sha1, &base_ent, p))
 995                die("failed to find delta-pack base object %s",
 996                    sha1_to_hex(base_sha1));
 997        base = unpack_entry_gently(&base_ent, type, &base_size);
 998        if (!base)
 999                die("failed to read delta-pack base object %s",
1000                    sha1_to_hex(base_sha1));
1001        result = patch_delta(base, base_size,
1002                             delta_data, delta_size,
1003                             &result_size);
1004        if (!result)
1005                die("failed to apply delta");
1006        free(delta_data);
1007        free(base);
1008        *sizep = result_size;
1009        return result;
1010}
1011
1012static void *unpack_non_delta_entry(unsigned char *data,
1013                                    unsigned long size,
1014                                    unsigned long left)
1015{
1016        int st;
1017        z_stream stream;
1018        unsigned char *buffer;
1019
1020        buffer = xmalloc(size + 1);
1021        buffer[size] = 0;
1022        memset(&stream, 0, sizeof(stream));
1023        stream.next_in = data;
1024        stream.avail_in = left;
1025        stream.next_out = buffer;
1026        stream.avail_out = size;
1027
1028        inflateInit(&stream);
1029        st = inflate(&stream, Z_FINISH);
1030        inflateEnd(&stream);
1031        if ((st != Z_STREAM_END) || stream.total_out != size) {
1032                free(buffer);
1033                return NULL;
1034        }
1035
1036        return buffer;
1037}
1038
1039static void *unpack_entry(struct pack_entry *entry,
1040                          char *type, unsigned long *sizep)
1041{
1042        struct packed_git *p = entry->p;
1043        void *retval;
1044
1045        if (use_packed_git(p))
1046                die("cannot map packed file");
1047        retval = unpack_entry_gently(entry, type, sizep);
1048        unuse_packed_git(p);
1049        if (!retval)
1050                die("corrupted pack file %s", p->pack_name);
1051        return retval;
1052}
1053
1054/* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1055void *unpack_entry_gently(struct pack_entry *entry,
1056                          char *type, unsigned long *sizep)
1057{
1058        struct packed_git *p = entry->p;
1059        unsigned long offset, size, left;
1060        unsigned char *pack;
1061        enum object_type kind;
1062        void *retval;
1063
1064        offset = unpack_object_header(p, entry->offset, &kind, &size);
1065        pack = p->pack_base + offset;
1066        left = p->pack_size - offset;
1067        switch (kind) {
1068        case OBJ_DELTA:
1069                retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1070                return retval;
1071        case OBJ_COMMIT:
1072                strcpy(type, "commit");
1073                break;
1074        case OBJ_TREE:
1075                strcpy(type, "tree");
1076                break;
1077        case OBJ_BLOB:
1078                strcpy(type, "blob");
1079                break;
1080        case OBJ_TAG:
1081                strcpy(type, "tag");
1082                break;
1083        default:
1084                return NULL;
1085        }
1086        *sizep = size;
1087        retval = unpack_non_delta_entry(pack, size, left);
1088        return retval;
1089}
1090
1091int num_packed_objects(const struct packed_git *p)
1092{
1093        /* See check_packed_git_idx() */
1094        return (p->index_size - 20 - 20 - 4*256) / 24;
1095}
1096
1097int nth_packed_object_sha1(const struct packed_git *p, int n,
1098                           unsigned char* sha1)
1099{
1100        void *index = p->index_base + 256;
1101        if (n < 0 || num_packed_objects(p) <= n)
1102                return -1;
1103        memcpy(sha1, (index + 24 * n + 4), 20);
1104        return 0;
1105}
1106
1107int find_pack_entry_one(const unsigned char *sha1,
1108                        struct pack_entry *e, struct packed_git *p)
1109{
1110        unsigned int *level1_ofs = p->index_base;
1111        int hi = ntohl(level1_ofs[*sha1]);
1112        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1113        void *index = p->index_base + 256;
1114
1115        do {
1116                int mi = (lo + hi) / 2;
1117                int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1118                if (!cmp) {
1119                        e->offset = ntohl(*((int*)(index + 24 * mi)));
1120                        memcpy(e->sha1, sha1, 20);
1121                        e->p = p;
1122                        return 1;
1123                }
1124                if (cmp > 0)
1125                        hi = mi;
1126                else
1127                        lo = mi+1;
1128        } while (lo < hi);
1129        return 0;
1130}
1131
1132static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1133{
1134        struct packed_git *p;
1135        prepare_packed_git();
1136
1137        for (p = packed_git; p; p = p->next) {
1138                if (find_pack_entry_one(sha1, e, p))
1139                        return 1;
1140        }
1141        return 0;
1142}
1143
1144struct packed_git *find_sha1_pack(const unsigned char *sha1, 
1145                                  struct packed_git *packs)
1146{
1147        struct packed_git *p;
1148        struct pack_entry e;
1149
1150        for (p = packs; p; p = p->next) {
1151                if (find_pack_entry_one(sha1, &e, p))
1152                        return p;
1153        }
1154        return NULL;
1155        
1156}
1157
1158int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1159{
1160        int status;
1161        unsigned long mapsize, size;
1162        void *map;
1163        z_stream stream;
1164        char hdr[128];
1165
1166        map = map_sha1_file_internal(sha1, &mapsize);
1167        if (!map) {
1168                struct pack_entry e;
1169
1170                if (!find_pack_entry(sha1, &e))
1171                        return error("unable to find %s", sha1_to_hex(sha1));
1172                return packed_object_info(&e, type, sizep);
1173        }
1174        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1175                status = error("unable to unpack %s header",
1176                               sha1_to_hex(sha1));
1177        if (parse_sha1_header(hdr, type, &size) < 0)
1178                status = error("unable to parse %s header", sha1_to_hex(sha1));
1179        else {
1180                status = 0;
1181                if (sizep)
1182                        *sizep = size;
1183        }
1184        inflateEnd(&stream);
1185        munmap(map, mapsize);
1186        return status;
1187}
1188
1189static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1190{
1191        struct pack_entry e;
1192
1193        if (!find_pack_entry(sha1, &e)) {
1194                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1195                return NULL;
1196        }
1197        return unpack_entry(&e, type, size);
1198}
1199
1200void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1201{
1202        unsigned long mapsize;
1203        void *map, *buf;
1204        struct pack_entry e;
1205
1206        if (find_pack_entry(sha1, &e))
1207                return read_packed_sha1(sha1, type, size);
1208        map = map_sha1_file_internal(sha1, &mapsize);
1209        if (map) {
1210                buf = unpack_sha1_file(map, mapsize, type, size);
1211                munmap(map, mapsize);
1212                return buf;
1213        }
1214        return NULL;
1215}
1216
1217void *read_object_with_reference(const unsigned char *sha1,
1218                                 const char *required_type,
1219                                 unsigned long *size,
1220                                 unsigned char *actual_sha1_return)
1221{
1222        char type[20];
1223        void *buffer;
1224        unsigned long isize;
1225        unsigned char actual_sha1[20];
1226
1227        memcpy(actual_sha1, sha1, 20);
1228        while (1) {
1229                int ref_length = -1;
1230                const char *ref_type = NULL;
1231
1232                buffer = read_sha1_file(actual_sha1, type, &isize);
1233                if (!buffer)
1234                        return NULL;
1235                if (!strcmp(type, required_type)) {
1236                        *size = isize;
1237                        if (actual_sha1_return)
1238                                memcpy(actual_sha1_return, actual_sha1, 20);
1239                        return buffer;
1240                }
1241                /* Handle references */
1242                else if (!strcmp(type, "commit"))
1243                        ref_type = "tree ";
1244                else if (!strcmp(type, "tag"))
1245                        ref_type = "object ";
1246                else {
1247                        free(buffer);
1248                        return NULL;
1249                }
1250                ref_length = strlen(ref_type);
1251
1252                if (memcmp(buffer, ref_type, ref_length) ||
1253                    get_sha1_hex(buffer + ref_length, actual_sha1)) {
1254                        free(buffer);
1255                        return NULL;
1256                }
1257                free(buffer);
1258                /* Now we have the ID of the referred-to object in
1259                 * actual_sha1.  Check again. */
1260        }
1261}
1262
1263char *write_sha1_file_prepare(void *buf,
1264                              unsigned long len,
1265                              const char *type,
1266                              unsigned char *sha1,
1267                              unsigned char *hdr,
1268                              int *hdrlen)
1269{
1270        SHA_CTX c;
1271
1272        /* Generate the header */
1273        *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1274
1275        /* Sha1.. */
1276        SHA1_Init(&c);
1277        SHA1_Update(&c, hdr, *hdrlen);
1278        SHA1_Update(&c, buf, len);
1279        SHA1_Final(sha1, &c);
1280
1281        return sha1_file_name(sha1);
1282}
1283
1284/*
1285 * Link the tempfile to the final place, possibly creating the
1286 * last directory level as you do so.
1287 *
1288 * Returns the errno on failure, 0 on success.
1289 */
1290static int link_temp_to_file(const char *tmpfile, char *filename)
1291{
1292        int ret;
1293
1294        if (!link(tmpfile, filename))
1295                return 0;
1296
1297        /*
1298         * Try to mkdir the last path component if that failed
1299         * with an ENOENT.
1300         *
1301         * Re-try the "link()" regardless of whether the mkdir
1302         * succeeds, since a race might mean that somebody
1303         * else succeeded.
1304         */
1305        ret = errno;
1306        if (ret == ENOENT) {
1307                char *dir = strrchr(filename, '/');
1308                if (dir) {
1309                        *dir = 0;
1310                        mkdir(filename, 0777);
1311                        if (adjust_shared_perm(filename))
1312                                return -2;
1313                        *dir = '/';
1314                        if (!link(tmpfile, filename))
1315                                return 0;
1316                        ret = errno;
1317                }
1318        }
1319        return ret;
1320}
1321
1322/*
1323 * Move the just written object into its final resting place
1324 */
1325int move_temp_to_file(const char *tmpfile, char *filename)
1326{
1327        int ret = link_temp_to_file(tmpfile, filename);
1328
1329        /*
1330         * Coda hack - coda doesn't like cross-directory links,
1331         * so we fall back to a rename, which will mean that it
1332         * won't be able to check collisions, but that's not a
1333         * big deal.
1334         *
1335         * The same holds for FAT formatted media.
1336         *
1337         * When this succeeds, we just return 0. We have nothing
1338         * left to unlink.
1339         */
1340        if (ret && ret != EEXIST) {
1341                if (!rename(tmpfile, filename))
1342                        return 0;
1343                ret = errno;
1344        }
1345        unlink(tmpfile);
1346        if (ret) {
1347                if (ret != EEXIST) {
1348                        fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1349                        return -1;
1350                }
1351                /* FIXME!!! Collision check here ? */
1352        }
1353
1354        return 0;
1355}
1356
1357int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1358{
1359        int size;
1360        unsigned char *compressed;
1361        z_stream stream;
1362        unsigned char sha1[20];
1363        char *filename;
1364        static char tmpfile[PATH_MAX];
1365        unsigned char hdr[50];
1366        int fd, hdrlen;
1367
1368        /* Normally if we have it in the pack then we do not bother writing
1369         * it out into .git/objects/??/?{38} file.
1370         */
1371        filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1372        if (returnsha1)
1373                memcpy(returnsha1, sha1, 20);
1374        if (has_sha1_file(sha1))
1375                return 0;
1376        fd = open(filename, O_RDONLY);
1377        if (fd >= 0) {
1378                /*
1379                 * FIXME!!! We might do collision checking here, but we'd
1380                 * need to uncompress the old file and check it. Later.
1381                 */
1382                close(fd);
1383                return 0;
1384        }
1385
1386        if (errno != ENOENT) {
1387                fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1388                return -1;
1389        }
1390
1391        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1392
1393        fd = mkstemp(tmpfile);
1394        if (fd < 0) {
1395                fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1396                return -1;
1397        }
1398
1399        /* Set it up */
1400        memset(&stream, 0, sizeof(stream));
1401        deflateInit(&stream, Z_BEST_COMPRESSION);
1402        size = deflateBound(&stream, len+hdrlen);
1403        compressed = xmalloc(size);
1404
1405        /* Compress it */
1406        stream.next_out = compressed;
1407        stream.avail_out = size;
1408
1409        /* First header.. */
1410        stream.next_in = hdr;
1411        stream.avail_in = hdrlen;
1412        while (deflate(&stream, 0) == Z_OK)
1413                /* nothing */;
1414
1415        /* Then the data itself.. */
1416        stream.next_in = buf;
1417        stream.avail_in = len;
1418        while (deflate(&stream, Z_FINISH) == Z_OK)
1419                /* nothing */;
1420        deflateEnd(&stream);
1421        size = stream.total_out;
1422
1423        if (write(fd, compressed, size) != size)
1424                die("unable to write file");
1425        fchmod(fd, 0444);
1426        close(fd);
1427        free(compressed);
1428
1429        return move_temp_to_file(tmpfile, filename);
1430}
1431
1432int write_sha1_to_fd(int fd, const unsigned char *sha1)
1433{
1434        ssize_t size;
1435        unsigned long objsize;
1436        int posn = 0;
1437        void *map = map_sha1_file_internal(sha1, &objsize);
1438        void *buf = map;
1439        void *temp_obj = NULL;
1440        z_stream stream;
1441
1442        if (!buf) {
1443                unsigned char *unpacked;
1444                unsigned long len;
1445                char type[20];
1446                char hdr[50];
1447                int hdrlen;
1448                // need to unpack and recompress it by itself
1449                unpacked = read_packed_sha1(sha1, type, &len);
1450
1451                hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1452
1453                /* Set it up */
1454                memset(&stream, 0, sizeof(stream));
1455                deflateInit(&stream, Z_BEST_COMPRESSION);
1456                size = deflateBound(&stream, len + hdrlen);
1457                temp_obj = buf = xmalloc(size);
1458
1459                /* Compress it */
1460                stream.next_out = buf;
1461                stream.avail_out = size;
1462                
1463                /* First header.. */
1464                stream.next_in = (void *)hdr;
1465                stream.avail_in = hdrlen;
1466                while (deflate(&stream, 0) == Z_OK)
1467                        /* nothing */;
1468
1469                /* Then the data itself.. */
1470                stream.next_in = unpacked;
1471                stream.avail_in = len;
1472                while (deflate(&stream, Z_FINISH) == Z_OK)
1473                        /* nothing */;
1474                deflateEnd(&stream);
1475                free(unpacked);
1476                
1477                objsize = stream.total_out;
1478        }
1479
1480        do {
1481                size = write(fd, buf + posn, objsize - posn);
1482                if (size <= 0) {
1483                        if (!size) {
1484                                fprintf(stderr, "write closed\n");
1485                        } else {
1486                                perror("write ");
1487                        }
1488                        return -1;
1489                }
1490                posn += size;
1491        } while (posn < objsize);
1492
1493        if (map)
1494                munmap(map, objsize);
1495        if (temp_obj)
1496                free(temp_obj);
1497
1498        return 0;
1499}
1500
1501int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1502                       size_t bufsize, size_t *bufposn)
1503{
1504        char tmpfile[PATH_MAX];
1505        int local;
1506        z_stream stream;
1507        unsigned char real_sha1[20];
1508        unsigned char discard[4096];
1509        int ret;
1510        SHA_CTX c;
1511
1512        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1513
1514        local = mkstemp(tmpfile);
1515        if (local < 0)
1516                return error("Couldn't open %s for %s",
1517                             tmpfile, sha1_to_hex(sha1));
1518
1519        memset(&stream, 0, sizeof(stream));
1520
1521        inflateInit(&stream);
1522
1523        SHA1_Init(&c);
1524
1525        do {
1526                ssize_t size;
1527                if (*bufposn) {
1528                        stream.avail_in = *bufposn;
1529                        stream.next_in = (unsigned char *) buffer;
1530                        do {
1531                                stream.next_out = discard;
1532                                stream.avail_out = sizeof(discard);
1533                                ret = inflate(&stream, Z_SYNC_FLUSH);
1534                                SHA1_Update(&c, discard, sizeof(discard) -
1535                                            stream.avail_out);
1536                        } while (stream.avail_in && ret == Z_OK);
1537                        write(local, buffer, *bufposn - stream.avail_in);
1538                        memmove(buffer, buffer + *bufposn - stream.avail_in,
1539                                stream.avail_in);
1540                        *bufposn = stream.avail_in;
1541                        if (ret != Z_OK)
1542                                break;
1543                }
1544                size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1545                if (size <= 0) {
1546                        close(local);
1547                        unlink(tmpfile);
1548                        if (!size)
1549                                return error("Connection closed?");
1550                        perror("Reading from connection");
1551                        return -1;
1552                }
1553                *bufposn += size;
1554        } while (1);
1555        inflateEnd(&stream);
1556
1557        close(local);
1558        SHA1_Final(real_sha1, &c);
1559        if (ret != Z_STREAM_END) {
1560                unlink(tmpfile);
1561                return error("File %s corrupted", sha1_to_hex(sha1));
1562        }
1563        if (memcmp(sha1, real_sha1, 20)) {
1564                unlink(tmpfile);
1565                return error("File %s has bad hash", sha1_to_hex(sha1));
1566        }
1567
1568        return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1569}
1570
1571int has_pack_index(const unsigned char *sha1)
1572{
1573        struct stat st;
1574        if (stat(sha1_pack_index_name(sha1), &st))
1575                return 0;
1576        return 1;
1577}
1578
1579int has_pack_file(const unsigned char *sha1)
1580{
1581        struct stat st;
1582        if (stat(sha1_pack_name(sha1), &st))
1583                return 0;
1584        return 1;
1585}
1586
1587int has_sha1_pack(const unsigned char *sha1)
1588{
1589        struct pack_entry e;
1590        return find_pack_entry(sha1, &e);
1591}
1592
1593int has_sha1_file(const unsigned char *sha1)
1594{
1595        struct stat st;
1596        struct pack_entry e;
1597
1598        if (find_pack_entry(sha1, &e))
1599                return 1;
1600        return find_sha1_file(sha1, &st) ? 1 : 0;
1601}
1602
1603int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1604{
1605        unsigned long size = 4096;
1606        char *buf = malloc(size);
1607        int iret, ret;
1608        unsigned long off = 0;
1609        unsigned char hdr[50];
1610        int hdrlen;
1611        do {
1612                iret = read(fd, buf + off, size - off);
1613                if (iret > 0) {
1614                        off += iret;
1615                        if (off == size) {
1616                                size *= 2;
1617                                buf = realloc(buf, size);
1618                        }
1619                }
1620        } while (iret > 0);
1621        if (iret < 0) {
1622                free(buf);
1623                return -1;
1624        }
1625        if (!type)
1626                type = "blob";
1627        if (write_object)
1628                ret = write_sha1_file(buf, off, type, sha1);
1629        else {
1630                write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
1631                ret = 0;
1632        }
1633        free(buf);
1634        return ret;
1635}
1636
1637int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1638{
1639        unsigned long size = st->st_size;
1640        void *buf;
1641        int ret;
1642        unsigned char hdr[50];
1643        int hdrlen;
1644
1645        buf = "";
1646        if (size)
1647                buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1648        close(fd);
1649        if (buf == MAP_FAILED)
1650                return -1;
1651
1652        if (!type)
1653                type = "blob";
1654        if (write_object)
1655                ret = write_sha1_file(buf, size, type, sha1);
1656        else {
1657                write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1658                ret = 0;
1659        }
1660        if (size)
1661                munmap(buf, size);
1662        return ret;
1663}
1664
1665int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1666{
1667        int fd;
1668        char *target;
1669
1670        switch (st->st_mode & S_IFMT) {
1671        case S_IFREG:
1672                fd = open(path, O_RDONLY);
1673                if (fd < 0)
1674                        return error("open(\"%s\"): %s", path,
1675                                     strerror(errno));
1676                if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1677                        return error("%s: failed to insert into database",
1678                                     path);
1679                break;
1680        case S_IFLNK:
1681                target = xmalloc(st->st_size+1);
1682                if (readlink(path, target, st->st_size+1) != st->st_size) {
1683                        char *errstr = strerror(errno);
1684                        free(target);
1685                        return error("readlink(\"%s\"): %s", path,
1686                                     errstr);
1687                }
1688                if (!write_object) {
1689                        unsigned char hdr[50];
1690                        int hdrlen;
1691                        write_sha1_file_prepare(target, st->st_size, "blob",
1692                                                sha1, hdr, &hdrlen);
1693                } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1694                        return error("%s: failed to insert into database",
1695                                     path);
1696                free(target);
1697                break;
1698        default:
1699                return error("%s: unsupported file type", path);
1700        }
1701        return 0;
1702}