sha1_file.con commit [PATCH] Factor out useful test case infrastructure from t/t6001... into t/t6000-lib.sh (ce11895)
   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 <sys/types.h>
  10#include <dirent.h>
  11#include "cache.h"
  12#include "delta.h"
  13#include "pack.h"
  14
  15#ifndef O_NOATIME
  16#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  17#define O_NOATIME 01000000
  18#else
  19#define O_NOATIME 0
  20#endif
  21#endif
  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
  49static int get_sha1_file(const char *path, unsigned char *result)
  50{
  51        char buffer[60];
  52        int fd = open(path, O_RDONLY);
  53        int len;
  54
  55        if (fd < 0)
  56                return -1;
  57        len = read(fd, buffer, sizeof(buffer));
  58        close(fd);
  59        if (len < 40)
  60                return -1;
  61        return get_sha1_hex(buffer, result);
  62}
  63
  64static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir;
  65static void setup_git_env(void)
  66{
  67        git_dir = gitenv(GIT_DIR_ENVIRONMENT);
  68        if (!git_dir)
  69                git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
  70        git_object_dir = gitenv(DB_ENVIRONMENT);
  71        if (!git_object_dir) {
  72                git_object_dir = xmalloc(strlen(git_dir) + 9);
  73                sprintf(git_object_dir, "%s/objects", git_dir);
  74        }
  75        git_refs_dir = xmalloc(strlen(git_dir) + 6);
  76        sprintf(git_refs_dir, "%s/refs", git_dir);
  77        git_index_file = gitenv(INDEX_ENVIRONMENT);
  78        if (!git_index_file) {
  79                git_index_file = xmalloc(strlen(git_dir) + 7);
  80                sprintf(git_index_file, "%s/index", git_dir);
  81        }
  82}
  83
  84char *get_object_directory(void)
  85{
  86        if (!git_object_dir)
  87                setup_git_env();
  88        return git_object_dir;
  89}
  90
  91char *get_refs_directory(void)
  92{
  93        if (!git_refs_dir)
  94                setup_git_env();
  95        return git_refs_dir;
  96}
  97
  98char *get_index_file(void)
  99{
 100        if (!git_index_file)
 101                setup_git_env();
 102        return git_index_file;
 103}
 104
 105char *git_path(const char *fmt, ...)
 106{
 107        static char pathname[PATH_MAX], *ret;
 108        va_list args;
 109        int len;
 110
 111        if (!git_dir)
 112                setup_git_env();
 113        len = strlen(git_dir);
 114        if (len > PATH_MAX-100)
 115                return "pad-path";
 116        memcpy(pathname, git_dir, len);
 117        if (len && git_dir[len-1] != '/')
 118                pathname[len++] = '/';
 119        va_start(args, fmt);
 120        vsnprintf(pathname + len, sizeof(pathname) - len, fmt, args);
 121        va_end(args);
 122        ret = pathname;
 123
 124        /* Clean it up */
 125        if (!memcmp(pathname, "./", 2)) {
 126                ret += 2;
 127                while (*ret == '/')
 128                        ret++;
 129        }
 130        return ret;
 131}
 132
 133int get_sha1(const char *str, unsigned char *sha1)
 134{
 135        static const char *prefix[] = {
 136                "",
 137                "refs",
 138                "refs/tags",
 139                "refs/heads",
 140                "refs/snap",
 141                NULL
 142        };
 143        const char **p;
 144
 145        if (!get_sha1_hex(str, sha1))
 146                return 0;
 147
 148        for (p = prefix; *p; p++) {
 149                char * pathname = git_path("%s/%s", *p, str);
 150                if (!get_sha1_file(pathname, sha1))
 151                        return 0;
 152        }
 153
 154        return -1;
 155}
 156
 157char * sha1_to_hex(const unsigned char *sha1)
 158{
 159        static char buffer[50];
 160        static const char hex[] = "0123456789abcdef";
 161        char *buf = buffer;
 162        int i;
 163
 164        for (i = 0; i < 20; i++) {
 165                unsigned int val = *sha1++;
 166                *buf++ = hex[val >> 4];
 167                *buf++ = hex[val & 0xf];
 168        }
 169        return buffer;
 170}
 171
 172static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 173{
 174        int i;
 175        for (i = 0; i < 20; i++) {
 176                static char hex[] = "0123456789abcdef";
 177                unsigned int val = sha1[i];
 178                char *pos = pathbuf + i*2 + (i > 0);
 179                *pos++ = hex[val >> 4];
 180                *pos = hex[val & 0xf];
 181        }
 182}
 183
 184/*
 185 * NOTE! This returns a statically allocated buffer, so you have to be
 186 * careful about using it. Do a "strdup()" if you need to save the
 187 * filename.
 188 *
 189 * Also note that this returns the location for creating.  Reading
 190 * SHA1 file can happen from any alternate directory listed in the
 191 * DB_ENVIRONMENT environment variable if it is not found in
 192 * the primary object database.
 193 */
 194char *sha1_file_name(const unsigned char *sha1)
 195{
 196        static char *name, *base;
 197
 198        if (!base) {
 199                const char *sha1_file_directory = get_object_directory();
 200                int len = strlen(sha1_file_directory);
 201                base = xmalloc(len + 60);
 202                memcpy(base, sha1_file_directory, len);
 203                memset(base+len, 0, 60);
 204                base[len] = '/';
 205                base[len+3] = '/';
 206                name = base + len + 1;
 207        }
 208        fill_sha1_path(name, sha1);
 209        return base;
 210}
 211
 212struct alternate_object_database *alt_odb;
 213
 214/*
 215 * Prepare alternate object database registry.
 216 * alt_odb points at an array of struct alternate_object_database.
 217 * This array is terminated with an element that has both its base
 218 * and name set to NULL.  alt_odb[n] comes from n'th non-empty
 219 * element from colon separated ALTERNATE_DB_ENVIRONMENT environment
 220 * variable, and its base points at a statically allocated buffer
 221 * that contains "/the/directory/corresponding/to/.git/objects/...",
 222 * while its name points just after the slash at the end of
 223 * ".git/objects/" in the example above, and has enough space to hold
 224 * 40-byte hex SHA1, an extra slash for the first level indirection,
 225 * and the terminating NUL.
 226 * This function allocates the alt_odb array and all the strings
 227 * pointed by base fields of the array elements with one xmalloc();
 228 * the string pool immediately follows the array.
 229 */
 230void prepare_alt_odb(void)
 231{
 232        int pass, totlen, i;
 233        const char *cp, *last;
 234        char *op = NULL;
 235        const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
 236
 237        if (alt_odb)
 238                return;
 239        /* The first pass counts how large an area to allocate to
 240         * hold the entire alt_odb structure, including array of
 241         * structs and path buffers for them.  The second pass fills
 242         * the structure and prepares the path buffers for use by
 243         * fill_sha1_path().
 244         */
 245        for (totlen = pass = 0; pass < 2; pass++) {
 246                last = alt;
 247                i = 0;
 248                do {
 249                        cp = strchr(last, ':') ? : last + strlen(last);
 250                        if (last != cp) {
 251                                /* 43 = 40-byte + 2 '/' + terminating NUL */
 252                                int pfxlen = cp - last;
 253                                int entlen = pfxlen + 43;
 254                                if (pass == 0)
 255                                        totlen += entlen;
 256                                else {
 257                                        alt_odb[i].base = op;
 258                                        alt_odb[i].name = op + pfxlen + 1;
 259                                        memcpy(op, last, pfxlen);
 260                                        op[pfxlen] = op[pfxlen + 3] = '/';
 261                                        op[entlen-1] = 0;
 262                                        op += entlen;
 263                                }
 264                                i++;
 265                        }
 266                        while (*cp && *cp == ':')
 267                                cp++;
 268                        last = cp;
 269                } while (*cp);
 270                if (pass)
 271                        break;
 272                alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
 273                alt_odb[i].base = alt_odb[i].name = NULL;
 274                op = (char*)(&alt_odb[i+1]);
 275        }
 276}
 277
 278static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 279{
 280        int i;
 281        char *name = sha1_file_name(sha1);
 282
 283        if (!stat(name, st))
 284                return name;
 285        prepare_alt_odb();
 286        for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
 287                fill_sha1_path(name, sha1);
 288                if (!stat(alt_odb[i].base, st))
 289                        return alt_odb[i].base;
 290        }
 291        return NULL;
 292}
 293
 294#define PACK_MAX_SZ (1<<26)
 295static int pack_used_ctr;
 296static unsigned long pack_mapped;
 297struct packed_git *packed_git;
 298
 299static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 300                                void **idx_map_)
 301{
 302        void *idx_map;
 303        unsigned int *index;
 304        unsigned long idx_size;
 305        int nr, i;
 306        int fd = open(path, O_RDONLY);
 307        struct stat st;
 308        if (fd < 0)
 309                return -1;
 310        if (fstat(fd, &st)) {
 311                close(fd);
 312                return -1;
 313        }
 314        idx_size = st.st_size;
 315        idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 316        close(fd);
 317        if (idx_map == MAP_FAILED)
 318                return -1;
 319
 320        index = idx_map;
 321        *idx_map_ = idx_map;
 322        *idx_size_ = idx_size;
 323
 324        /* check index map */
 325        if (idx_size < 4*256 + 20 + 20)
 326                return error("index file too small");
 327        nr = 0;
 328        for (i = 0; i < 256; i++) {
 329                unsigned int n = ntohl(index[i]);
 330                if (n < nr)
 331                        return error("non-monotonic index");
 332                nr = n;
 333        }
 334
 335        /*
 336         * Total size:
 337         *  - 256 index entries 4 bytes each
 338         *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 339         *  - 20-byte SHA1 of the packfile
 340         *  - 20-byte SHA1 file checksum
 341         */
 342        if (idx_size != 4*256 + nr * 24 + 20 + 20)
 343                return error("wrong index file size");
 344
 345        return 0;
 346}
 347
 348static int unuse_one_packed_git(void)
 349{
 350        struct packed_git *p, *lru = NULL;
 351
 352        for (p = packed_git; p; p = p->next) {
 353                if (p->pack_use_cnt || !p->pack_base)
 354                        continue;
 355                if (!lru || p->pack_last_used < lru->pack_last_used)
 356                        lru = p;
 357        }
 358        if (!lru)
 359                return 0;
 360        munmap(lru->pack_base, lru->pack_size);
 361        lru->pack_base = NULL;
 362        return 1;
 363}
 364
 365void unuse_packed_git(struct packed_git *p)
 366{
 367        p->pack_use_cnt--;
 368}
 369
 370int use_packed_git(struct packed_git *p)
 371{
 372        if (!p->pack_base) {
 373                int fd;
 374                struct stat st;
 375                void *map;
 376
 377                pack_mapped += p->pack_size;
 378                while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 379                        ; /* nothing */
 380                fd = open(p->pack_name, O_RDONLY);
 381                if (fd < 0)
 382                        die("packfile %s cannot be opened", p->pack_name);
 383                if (fstat(fd, &st)) {
 384                        close(fd);
 385                        die("packfile %s cannot be opened", p->pack_name);
 386                }
 387                if (st.st_size != p->pack_size)
 388                        die("packfile %s size mismatch.", p->pack_name);
 389                map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 390                close(fd);
 391                if (map == MAP_FAILED)
 392                        die("packfile %s cannot be mapped.", p->pack_name);
 393                p->pack_base = map;
 394
 395                /* Check if the pack file matches with the index file.
 396                 * this is cheap.
 397                 */
 398                if (memcmp((char*)(p->index_base) + p->index_size - 40,
 399                           p->pack_base + p->pack_size - 20, 20))
 400                        die("packfile %s does not match index.", p->pack_name);
 401        }
 402        p->pack_last_used = pack_used_ctr++;
 403        p->pack_use_cnt++;
 404        return 0;
 405}
 406
 407struct packed_git *add_packed_git(char *path, int path_len)
 408{
 409        struct stat st;
 410        struct packed_git *p;
 411        unsigned long idx_size;
 412        void *idx_map;
 413
 414        if (check_packed_git_idx(path, &idx_size, &idx_map))
 415                return NULL;
 416
 417        /* do we have a corresponding .pack file? */
 418        strcpy(path + path_len - 4, ".pack");
 419        if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 420                munmap(idx_map, idx_size);
 421                return NULL;
 422        }
 423        /* ok, it looks sane as far as we can check without
 424         * actually mapping the pack file.
 425         */
 426        p = xmalloc(sizeof(*p) + path_len + 2);
 427        strcpy(p->pack_name, path);
 428        p->index_size = idx_size;
 429        p->pack_size = st.st_size;
 430        p->index_base = idx_map;
 431        p->next = NULL;
 432        p->pack_base = NULL;
 433        p->pack_last_used = 0;
 434        p->pack_use_cnt = 0;
 435        return p;
 436}
 437
 438static void prepare_packed_git_one(char *objdir)
 439{
 440        char path[PATH_MAX];
 441        int len;
 442        DIR *dir;
 443        struct dirent *de;
 444
 445        sprintf(path, "%s/pack", objdir);
 446        len = strlen(path);
 447        dir = opendir(path);
 448        if (!dir)
 449                return;
 450        path[len++] = '/';
 451        while ((de = readdir(dir)) != NULL) {
 452                int namelen = strlen(de->d_name);
 453                struct packed_git *p;
 454
 455                if (strcmp(de->d_name + namelen - 4, ".idx"))
 456                        continue;
 457
 458                /* we have .idx.  Is it a file we can map? */
 459                strcpy(path + len, de->d_name);
 460                p = add_packed_git(path, len + namelen);
 461                if (!p)
 462                        continue;
 463                p->next = packed_git;
 464                packed_git = p;
 465        }
 466        closedir(dir);
 467}
 468
 469void prepare_packed_git(void)
 470{
 471        int i;
 472        static int run_once = 0;
 473
 474        if (run_once++)
 475                return;
 476
 477        prepare_packed_git_one(get_object_directory());
 478        prepare_alt_odb();
 479        for (i = 0; alt_odb[i].base != NULL; i++) {
 480                alt_odb[i].name[0] = 0;
 481                prepare_packed_git_one(alt_odb[i].base);
 482        }
 483}
 484
 485int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 486{
 487        char header[100];
 488        unsigned char real_sha1[20];
 489        SHA_CTX c;
 490
 491        SHA1_Init(&c);
 492        SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 493        SHA1_Update(&c, map, size);
 494        SHA1_Final(real_sha1, &c);
 495        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 496}
 497
 498static void *map_sha1_file_internal(const unsigned char *sha1,
 499                                    unsigned long *size,
 500                                    int say_error)
 501{
 502        struct stat st;
 503        void *map;
 504        int fd;
 505        char *filename = find_sha1_file(sha1, &st);
 506
 507        if (!filename) {
 508                if (say_error)
 509                        error("cannot map sha1 file %s", sha1_to_hex(sha1));
 510                return NULL;
 511        }
 512
 513        fd = open(filename, O_RDONLY | sha1_file_open_flag);
 514        if (fd < 0) {
 515                /* See if it works without O_NOATIME */
 516                switch (sha1_file_open_flag) {
 517                default:
 518                        fd = open(filename, O_RDONLY);
 519                        if (fd >= 0)
 520                                break;
 521                /* Fallthrough */
 522                case 0:
 523                        if (say_error)
 524                                perror(filename);
 525                        return NULL;
 526                }
 527
 528                /* If it failed once, it will probably fail again.
 529                 * Stop using O_NOATIME
 530                 */
 531                sha1_file_open_flag = 0;
 532        }
 533        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 534        close(fd);
 535        if (-1 == (int)(long)map)
 536                return NULL;
 537        *size = st.st_size;
 538        return map;
 539}
 540
 541void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 542{
 543        return map_sha1_file_internal(sha1, size, 1);
 544}
 545
 546int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 547{
 548        /* Get the data stream */
 549        memset(stream, 0, sizeof(*stream));
 550        stream->next_in = map;
 551        stream->avail_in = mapsize;
 552        stream->next_out = buffer;
 553        stream->avail_out = size;
 554
 555        inflateInit(stream);
 556        return inflate(stream, 0);
 557}
 558
 559static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 560{
 561        int bytes = strlen(buffer) + 1;
 562        unsigned char *buf = xmalloc(1+size);
 563
 564        memcpy(buf, buffer + bytes, stream->total_out - bytes);
 565        bytes = stream->total_out - bytes;
 566        if (bytes < size) {
 567                stream->next_out = buf + bytes;
 568                stream->avail_out = size - bytes;
 569                while (inflate(stream, Z_FINISH) == Z_OK)
 570                        /* nothing */;
 571        }
 572        buf[size] = 0;
 573        inflateEnd(stream);
 574        return buf;
 575}
 576
 577/*
 578 * We used to just use "sscanf()", but that's actually way
 579 * too permissive for what we want to check. So do an anal
 580 * object header parse by hand.
 581 */
 582int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 583{
 584        int i;
 585        unsigned long size;
 586
 587        /*
 588         * The type can be at most ten bytes (including the 
 589         * terminating '\0' that we add), and is followed by
 590         * a space. 
 591         */
 592        i = 10;
 593        for (;;) {
 594                char c = *hdr++;
 595                if (c == ' ')
 596                        break;
 597                if (!--i)
 598                        return -1;
 599                *type++ = c;
 600        }
 601        *type = 0;
 602
 603        /*
 604         * The length must follow immediately, and be in canonical
 605         * decimal format (ie "010" is not valid).
 606         */
 607        size = *hdr++ - '0';
 608        if (size > 9)
 609                return -1;
 610        if (size) {
 611                for (;;) {
 612                        unsigned long c = *hdr - '0';
 613                        if (c > 9)
 614                                break;
 615                        hdr++;
 616                        size = size * 10 + c;
 617                }
 618        }
 619        *sizep = size;
 620
 621        /*
 622         * The length must be followed by a zero byte
 623         */
 624        return *hdr ? -1 : 0;
 625}
 626
 627void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 628{
 629        int ret;
 630        z_stream stream;
 631        char hdr[8192];
 632
 633        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 634        if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 635                return NULL;
 636
 637        return unpack_sha1_rest(&stream, hdr, *size);
 638}
 639
 640/* forward declaration for a mutually recursive function */
 641static int packed_object_info(struct pack_entry *entry,
 642                              char *type, unsigned long *sizep);
 643
 644static int packed_delta_info(unsigned char *base_sha1,
 645                             unsigned long delta_size,
 646                             unsigned long left,
 647                             char *type,
 648                             unsigned long *sizep,
 649                             struct packed_git *p)
 650{
 651        struct pack_entry base_ent;
 652
 653        if (left < 20)
 654                die("truncated pack file");
 655
 656        /* The base entry _must_ be in the same pack */
 657        if (!find_pack_entry_one(base_sha1, &base_ent, p))
 658                die("failed to find delta-pack base object %s",
 659                    sha1_to_hex(base_sha1));
 660
 661        /* We choose to only get the type of the base object and
 662         * ignore potentially corrupt pack file that expects the delta
 663         * based on a base with a wrong size.  This saves tons of
 664         * inflate() calls.
 665         */
 666
 667        if (packed_object_info(&base_ent, type, NULL))
 668                die("cannot get info for delta-pack base");
 669
 670        if (sizep) {
 671                const unsigned char *data;
 672                unsigned char delta_head[64];
 673                unsigned long result_size;
 674                z_stream stream;
 675                int st;
 676
 677                memset(&stream, 0, sizeof(stream));
 678
 679                data = stream.next_in = base_sha1 + 20;
 680                stream.avail_in = left - 20;
 681                stream.next_out = delta_head;
 682                stream.avail_out = sizeof(delta_head);
 683
 684                inflateInit(&stream);
 685                st = inflate(&stream, Z_FINISH);
 686                inflateEnd(&stream);
 687                if ((st != Z_STREAM_END) &&
 688                    stream.total_out != sizeof(delta_head))
 689                        die("delta data unpack-initial failed");
 690
 691                /* Examine the initial part of the delta to figure out
 692                 * the result size.
 693                 */
 694                data = delta_head;
 695                get_delta_hdr_size(&data); /* ignore base size */
 696
 697                /* Read the result size */
 698                result_size = get_delta_hdr_size(&data);
 699                *sizep = result_size;
 700        }
 701        return 0;
 702}
 703
 704static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 705        enum object_type *type, unsigned long *sizep)
 706{
 707        unsigned shift;
 708        unsigned char *pack, c;
 709        unsigned long size;
 710
 711        if (offset >= p->pack_size)
 712                die("object offset outside of pack file");
 713
 714        pack =  p->pack_base + offset;
 715        c = *pack++;
 716        offset++;
 717        *type = (c >> 4) & 7;
 718        size = c & 15;
 719        shift = 4;
 720        while (c & 0x80) {
 721                if (offset >= p->pack_size)
 722                        die("object offset outside of pack file");
 723                c = *pack++;
 724                offset++;
 725                size += (c & 0x7f) << shift;
 726                shift += 7;
 727        }
 728        *sizep = size;
 729        return offset;
 730}
 731
 732void packed_object_info_detail(struct pack_entry *e,
 733                               char *type,
 734                               unsigned long *size,
 735                               unsigned long *store_size,
 736                               int *delta_chain_length,
 737                               unsigned char *base_sha1)
 738{
 739        struct packed_git *p = e->p;
 740        unsigned long offset, left;
 741        unsigned char *pack;
 742        enum object_type kind;
 743
 744        offset = unpack_object_header(p, e->offset, &kind, size);
 745        pack = p->pack_base + offset;
 746        left = p->pack_size - offset;
 747        if (kind != OBJ_DELTA)
 748                *delta_chain_length = 0;
 749        else {
 750                int chain_length = 0;
 751                memcpy(base_sha1, pack, 20);
 752                do {
 753                        struct pack_entry base_ent;
 754                        unsigned long junk;
 755
 756                        find_pack_entry_one(pack, &base_ent, p);
 757                        offset = unpack_object_header(p, base_ent.offset,
 758                                                      &kind, &junk);
 759                        pack = p->pack_base + offset;
 760                        chain_length++;
 761                } while (kind == OBJ_DELTA);
 762                *delta_chain_length = chain_length;
 763        }
 764        switch (kind) {
 765        case OBJ_COMMIT:
 766                strcpy(type, "commit");
 767                break;
 768        case OBJ_TREE:
 769                strcpy(type, "tree");
 770                break;
 771        case OBJ_BLOB:
 772                strcpy(type, "blob");
 773                break;
 774        case OBJ_TAG:
 775                strcpy(type, "tag");
 776                break;
 777        default:
 778                die("corrupted pack file");
 779        }
 780        *store_size = 0; /* notyet */
 781}
 782
 783static int packed_object_info(struct pack_entry *entry,
 784                              char *type, unsigned long *sizep)
 785{
 786        struct packed_git *p = entry->p;
 787        unsigned long offset, size, left;
 788        unsigned char *pack;
 789        enum object_type kind;
 790        int retval;
 791
 792        if (use_packed_git(p))
 793                die("cannot map packed file");
 794
 795        offset = unpack_object_header(p, entry->offset, &kind, &size);
 796        pack = p->pack_base + offset;
 797        left = p->pack_size - offset;
 798
 799        switch (kind) {
 800        case OBJ_DELTA:
 801                retval = packed_delta_info(pack, size, left, type, sizep, p);
 802                unuse_packed_git(p);
 803                return retval;
 804        case OBJ_COMMIT:
 805                strcpy(type, "commit");
 806                break;
 807        case OBJ_TREE:
 808                strcpy(type, "tree");
 809                break;
 810        case OBJ_BLOB:
 811                strcpy(type, "blob");
 812                break;
 813        case OBJ_TAG:
 814                strcpy(type, "tag");
 815                break;
 816        default:
 817                die("corrupted pack file");
 818        }
 819        if (sizep)
 820                *sizep = size;
 821        unuse_packed_git(p);
 822        return 0;
 823}
 824
 825/* forward declaration for a mutually recursive function */
 826static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 827
 828static void *unpack_delta_entry(unsigned char *base_sha1,
 829                                unsigned long delta_size,
 830                                unsigned long left,
 831                                char *type,
 832                                unsigned long *sizep,
 833                                struct packed_git *p)
 834{
 835        struct pack_entry base_ent;
 836        void *data, *delta_data, *result, *base;
 837        unsigned long data_size, result_size, base_size;
 838        z_stream stream;
 839        int st;
 840
 841        if (left < 20)
 842                die("truncated pack file");
 843        data = base_sha1 + 20;
 844        data_size = left - 20;
 845        delta_data = xmalloc(delta_size);
 846
 847        memset(&stream, 0, sizeof(stream));
 848
 849        stream.next_in = data;
 850        stream.avail_in = data_size;
 851        stream.next_out = delta_data;
 852        stream.avail_out = delta_size;
 853
 854        inflateInit(&stream);
 855        st = inflate(&stream, Z_FINISH);
 856        inflateEnd(&stream);
 857        if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 858                die("delta data unpack failed");
 859
 860        /* The base entry _must_ be in the same pack */
 861        if (!find_pack_entry_one(base_sha1, &base_ent, p))
 862                die("failed to find delta-pack base object %s",
 863                    sha1_to_hex(base_sha1));
 864        base = unpack_entry_gently(&base_ent, type, &base_size);
 865        if (!base)
 866                die("failed to read delta-pack base object %s",
 867                    sha1_to_hex(base_sha1));
 868        result = patch_delta(base, base_size,
 869                             delta_data, delta_size,
 870                             &result_size);
 871        if (!result)
 872                die("failed to apply delta");
 873        free(delta_data);
 874        free(base);
 875        *sizep = result_size;
 876        return result;
 877}
 878
 879static void *unpack_non_delta_entry(unsigned char *data,
 880                                    unsigned long size,
 881                                    unsigned long left)
 882{
 883        int st;
 884        z_stream stream;
 885        unsigned char *buffer;
 886
 887        buffer = xmalloc(size + 1);
 888        buffer[size] = 0;
 889        memset(&stream, 0, sizeof(stream));
 890        stream.next_in = data;
 891        stream.avail_in = left;
 892        stream.next_out = buffer;
 893        stream.avail_out = size;
 894
 895        inflateInit(&stream);
 896        st = inflate(&stream, Z_FINISH);
 897        inflateEnd(&stream);
 898        if ((st != Z_STREAM_END) || stream.total_out != size) {
 899                free(buffer);
 900                return NULL;
 901        }
 902
 903        return buffer;
 904}
 905
 906static void *unpack_entry(struct pack_entry *entry,
 907                          char *type, unsigned long *sizep)
 908{
 909        struct packed_git *p = entry->p;
 910        void *retval;
 911
 912        if (use_packed_git(p))
 913                die("cannot map packed file");
 914        retval = unpack_entry_gently(entry, type, sizep);
 915        unuse_packed_git(p);
 916        if (!retval)
 917                die("corrupted pack file");
 918        return retval;
 919}
 920
 921/* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
 922void *unpack_entry_gently(struct pack_entry *entry,
 923                          char *type, unsigned long *sizep)
 924{
 925        struct packed_git *p = entry->p;
 926        unsigned long offset, size, left;
 927        unsigned char *pack;
 928        enum object_type kind;
 929        void *retval;
 930
 931        offset = unpack_object_header(p, entry->offset, &kind, &size);
 932        pack = p->pack_base + offset;
 933        left = p->pack_size - offset;
 934        switch (kind) {
 935        case OBJ_DELTA:
 936                retval = unpack_delta_entry(pack, size, left, type, sizep, p);
 937                return retval;
 938        case OBJ_COMMIT:
 939                strcpy(type, "commit");
 940                break;
 941        case OBJ_TREE:
 942                strcpy(type, "tree");
 943                break;
 944        case OBJ_BLOB:
 945                strcpy(type, "blob");
 946                break;
 947        case OBJ_TAG:
 948                strcpy(type, "tag");
 949                break;
 950        default:
 951                return NULL;
 952        }
 953        *sizep = size;
 954        retval = unpack_non_delta_entry(pack, size, left);
 955        return retval;
 956}
 957
 958int num_packed_objects(const struct packed_git *p)
 959{
 960        /* See check_packed_git_idx() */
 961        return (p->index_size - 20 - 20 - 4*256) / 24;
 962}
 963
 964int nth_packed_object_sha1(const struct packed_git *p, int n,
 965                           unsigned char* sha1)
 966{
 967        void *index = p->index_base + 256;
 968        if (n < 0 || num_packed_objects(p) <= n)
 969                return -1;
 970        memcpy(sha1, (index + 24 * n + 4), 20);
 971        return 0;
 972}
 973
 974int find_pack_entry_one(const unsigned char *sha1,
 975                        struct pack_entry *e, struct packed_git *p)
 976{
 977        unsigned int *level1_ofs = p->index_base;
 978        int hi = ntohl(level1_ofs[*sha1]);
 979        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
 980        void *index = p->index_base + 256;
 981
 982        do {
 983                int mi = (lo + hi) / 2;
 984                int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
 985                if (!cmp) {
 986                        e->offset = ntohl(*((int*)(index + 24 * mi)));
 987                        memcpy(e->sha1, sha1, 20);
 988                        e->p = p;
 989                        return 1;
 990                }
 991                if (cmp > 0)
 992                        hi = mi;
 993                else
 994                        lo = mi+1;
 995        } while (lo < hi);
 996        return 0;
 997}
 998
 999static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1000{
1001        struct packed_git *p;
1002        prepare_packed_git();
1003
1004        for (p = packed_git; p; p = p->next) {
1005                if (find_pack_entry_one(sha1, e, p))
1006                        return 1;
1007        }
1008        return 0;
1009}
1010
1011int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1012{
1013        int status;
1014        unsigned long mapsize, size;
1015        void *map;
1016        z_stream stream;
1017        char hdr[128];
1018
1019        map = map_sha1_file_internal(sha1, &mapsize, 0);
1020        if (!map) {
1021                struct pack_entry e;
1022
1023                if (!find_pack_entry(sha1, &e))
1024                        return error("unable to find %s", sha1_to_hex(sha1));
1025                return packed_object_info(&e, type, sizep);
1026        }
1027        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1028                status = error("unable to unpack %s header",
1029                               sha1_to_hex(sha1));
1030        if (parse_sha1_header(hdr, type, &size) < 0)
1031                status = error("unable to parse %s header", sha1_to_hex(sha1));
1032        else {
1033                status = 0;
1034                if (sizep)
1035                        *sizep = size;
1036        }
1037        inflateEnd(&stream);
1038        munmap(map, mapsize);
1039        return status;
1040}
1041
1042static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1043{
1044        struct pack_entry e;
1045
1046        if (!find_pack_entry(sha1, &e)) {
1047                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1048                return NULL;
1049        }
1050        return unpack_entry(&e, type, size);
1051}
1052
1053void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1054{
1055        unsigned long mapsize;
1056        void *map, *buf;
1057
1058        map = map_sha1_file_internal(sha1, &mapsize, 0);
1059        if (map) {
1060                buf = unpack_sha1_file(map, mapsize, type, size);
1061                munmap(map, mapsize);
1062                return buf;
1063        }
1064        return read_packed_sha1(sha1, type, size);
1065}
1066
1067void *read_object_with_reference(const unsigned char *sha1,
1068                                 const char *required_type,
1069                                 unsigned long *size,
1070                                 unsigned char *actual_sha1_return)
1071{
1072        char type[20];
1073        void *buffer;
1074        unsigned long isize;
1075        unsigned char actual_sha1[20];
1076
1077        memcpy(actual_sha1, sha1, 20);
1078        while (1) {
1079                int ref_length = -1;
1080                const char *ref_type = NULL;
1081
1082                buffer = read_sha1_file(actual_sha1, type, &isize);
1083                if (!buffer)
1084                        return NULL;
1085                if (!strcmp(type, required_type)) {
1086                        *size = isize;
1087                        if (actual_sha1_return)
1088                                memcpy(actual_sha1_return, actual_sha1, 20);
1089                        return buffer;
1090                }
1091                /* Handle references */
1092                else if (!strcmp(type, "commit"))
1093                        ref_type = "tree ";
1094                else if (!strcmp(type, "tag"))
1095                        ref_type = "object ";
1096                else {
1097                        free(buffer);
1098                        return NULL;
1099                }
1100                ref_length = strlen(ref_type);
1101
1102                if (memcmp(buffer, ref_type, ref_length) ||
1103                    get_sha1_hex(buffer + ref_length, actual_sha1)) {
1104                        free(buffer);
1105                        return NULL;
1106                }
1107                /* Now we have the ID of the referred-to object in
1108                 * actual_sha1.  Check again. */
1109        }
1110}
1111
1112static char *write_sha1_file_prepare(void *buf,
1113                                     unsigned long len,
1114                                     const char *type,
1115                                     unsigned char *sha1,
1116                                     unsigned char *hdr,
1117                                     int *hdrlen)
1118{
1119        SHA_CTX c;
1120
1121        /* Generate the header */
1122        *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1123
1124        /* Sha1.. */
1125        SHA1_Init(&c);
1126        SHA1_Update(&c, hdr, *hdrlen);
1127        SHA1_Update(&c, buf, len);
1128        SHA1_Final(sha1, &c);
1129
1130        return sha1_file_name(sha1);
1131}
1132
1133int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1134{
1135        int size;
1136        unsigned char *compressed;
1137        z_stream stream;
1138        unsigned char sha1[20];
1139        char *filename;
1140        static char tmpfile[PATH_MAX];
1141        unsigned char hdr[50];
1142        int fd, hdrlen, ret;
1143
1144        /* Normally if we have it in the pack then we do not bother writing
1145         * it out into .git/objects/??/?{38} file.
1146         */
1147        filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1148        if (returnsha1)
1149                memcpy(returnsha1, sha1, 20);
1150        if (has_sha1_file(sha1))
1151                return 0;
1152        fd = open(filename, O_RDONLY);
1153        if (fd >= 0) {
1154                /*
1155                 * FIXME!!! We might do collision checking here, but we'd
1156                 * need to uncompress the old file and check it. Later.
1157                 */
1158                close(fd);
1159                return 0;
1160        }
1161
1162        if (errno != ENOENT) {
1163                fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1164                return -1;
1165        }
1166
1167        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1168
1169        fd = mkstemp(tmpfile);
1170        if (fd < 0) {
1171                fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1172                return -1;
1173        }
1174
1175        /* Set it up */
1176        memset(&stream, 0, sizeof(stream));
1177        deflateInit(&stream, Z_BEST_COMPRESSION);
1178        size = deflateBound(&stream, len+hdrlen);
1179        compressed = xmalloc(size);
1180
1181        /* Compress it */
1182        stream.next_out = compressed;
1183        stream.avail_out = size;
1184
1185        /* First header.. */
1186        stream.next_in = hdr;
1187        stream.avail_in = hdrlen;
1188        while (deflate(&stream, 0) == Z_OK)
1189                /* nothing */;
1190
1191        /* Then the data itself.. */
1192        stream.next_in = buf;
1193        stream.avail_in = len;
1194        while (deflate(&stream, Z_FINISH) == Z_OK)
1195                /* nothing */;
1196        deflateEnd(&stream);
1197        size = stream.total_out;
1198
1199        if (write(fd, compressed, size) != size)
1200                die("unable to write file");
1201        fchmod(fd, 0444);
1202        close(fd);
1203        free(compressed);
1204
1205        ret = link(tmpfile, filename);
1206        if (ret < 0) {
1207                ret = errno;
1208
1209                /*
1210                 * Coda hack - coda doesn't like cross-directory links,
1211                 * so we fall back to a rename, which will mean that it
1212                 * won't be able to check collisions, but that's not a
1213                 * big deal.
1214                 *
1215                 * When this succeeds, we just return 0. We have nothing
1216                 * left to unlink.
1217                 */
1218                if (ret == EXDEV && !rename(tmpfile, filename))
1219                        return 0;
1220        }
1221        unlink(tmpfile);
1222        if (ret) {
1223                if (ret != EEXIST) {
1224                        fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1225                        return -1;
1226                }
1227                /* FIXME!!! Collision check here ? */
1228        }
1229
1230        return 0;
1231}
1232
1233int write_sha1_from_fd(const unsigned char *sha1, int fd)
1234{
1235        char *filename = sha1_file_name(sha1);
1236
1237        int local;
1238        z_stream stream;
1239        unsigned char real_sha1[20];
1240        unsigned char buf[4096];
1241        unsigned char discard[4096];
1242        int ret;
1243        SHA_CTX c;
1244
1245        local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
1246
1247        if (local < 0)
1248                return error("Couldn't open %s\n", filename);
1249
1250        memset(&stream, 0, sizeof(stream));
1251
1252        inflateInit(&stream);
1253
1254        SHA1_Init(&c);
1255
1256        do {
1257                ssize_t size;
1258                size = read(fd, buf, 4096);
1259                if (size <= 0) {
1260                        close(local);
1261                        unlink(filename);
1262                        if (!size)
1263                                return error("Connection closed?");
1264                        perror("Reading from connection");
1265                        return -1;
1266                }
1267                write(local, buf, size);
1268                stream.avail_in = size;
1269                stream.next_in = buf;
1270                do {
1271                        stream.next_out = discard;
1272                        stream.avail_out = sizeof(discard);
1273                        ret = inflate(&stream, Z_SYNC_FLUSH);
1274                        SHA1_Update(&c, discard, sizeof(discard) -
1275                                    stream.avail_out);
1276                } while (stream.avail_in && ret == Z_OK);
1277                
1278        } while (ret == Z_OK);
1279        inflateEnd(&stream);
1280
1281        close(local);
1282        SHA1_Final(real_sha1, &c);
1283        if (ret != Z_STREAM_END) {
1284                unlink(filename);
1285                return error("File %s corrupted", sha1_to_hex(sha1));
1286        }
1287        if (memcmp(sha1, real_sha1, 20)) {
1288                unlink(filename);
1289                return error("File %s has bad hash\n", sha1_to_hex(sha1));
1290        }
1291        
1292        return 0;
1293}
1294
1295int has_sha1_pack(const unsigned char *sha1)
1296{
1297        struct pack_entry e;
1298        return find_pack_entry(sha1, &e);
1299}
1300
1301int has_sha1_file(const unsigned char *sha1)
1302{
1303        struct stat st;
1304        struct pack_entry e;
1305
1306        if (find_sha1_file(sha1, &st))
1307                return 1;
1308        return find_pack_entry(sha1, &e);
1309}
1310
1311int index_fd(unsigned char *sha1, int fd, struct stat *st)
1312{
1313        unsigned long size = st->st_size;
1314        void *buf;
1315        int ret;
1316
1317        buf = "";
1318        if (size)
1319                buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1320        close(fd);
1321        if ((int)(long)buf == -1)
1322                return -1;
1323
1324        ret = write_sha1_file(buf, size, "blob", sha1);
1325        if (size)
1326                munmap(buf, size);
1327        return ret;
1328}