sha1_file.con commit Merge branch 'js/fetch-progress' (early part) (3ddad98)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 *
   6 * This handles basic git sha1 object files - packing, unpacking,
   7 * creation etc.
   8 */
   9#include "cache.h"
  10#include "delta.h"
  11#include "pack.h"
  12#include "blob.h"
  13#include "commit.h"
  14#include "tag.h"
  15#include "tree.h"
  16
  17#ifndef O_NOATIME
  18#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  19#define O_NOATIME 01000000
  20#else
  21#define O_NOATIME 0
  22#endif
  23#endif
  24
  25#ifdef NO_C99_FORMAT
  26#define SZ_FMT "lu"
  27#else
  28#define SZ_FMT "zu"
  29#endif
  30
  31const unsigned char null_sha1[20];
  32
  33static unsigned int sha1_file_open_flag = O_NOATIME;
  34
  35signed char hexval_table[256] = {
  36         -1, -1, -1, -1, -1, -1, -1, -1,                /* 00-07 */
  37         -1, -1, -1, -1, -1, -1, -1, -1,                /* 08-0f */
  38         -1, -1, -1, -1, -1, -1, -1, -1,                /* 10-17 */
  39         -1, -1, -1, -1, -1, -1, -1, -1,                /* 18-1f */
  40         -1, -1, -1, -1, -1, -1, -1, -1,                /* 20-27 */
  41         -1, -1, -1, -1, -1, -1, -1, -1,                /* 28-2f */
  42          0,  1,  2,  3,  4,  5,  6,  7,                /* 30-37 */
  43          8,  9, -1, -1, -1, -1, -1, -1,                /* 38-3f */
  44         -1, 10, 11, 12, 13, 14, 15, -1,                /* 40-47 */
  45         -1, -1, -1, -1, -1, -1, -1, -1,                /* 48-4f */
  46         -1, -1, -1, -1, -1, -1, -1, -1,                /* 50-57 */
  47         -1, -1, -1, -1, -1, -1, -1, -1,                /* 58-5f */
  48         -1, 10, 11, 12, 13, 14, 15, -1,                /* 60-67 */
  49         -1, -1, -1, -1, -1, -1, -1, -1,                /* 68-67 */
  50         -1, -1, -1, -1, -1, -1, -1, -1,                /* 70-77 */
  51         -1, -1, -1, -1, -1, -1, -1, -1,                /* 78-7f */
  52         -1, -1, -1, -1, -1, -1, -1, -1,                /* 80-87 */
  53         -1, -1, -1, -1, -1, -1, -1, -1,                /* 88-8f */
  54         -1, -1, -1, -1, -1, -1, -1, -1,                /* 90-97 */
  55         -1, -1, -1, -1, -1, -1, -1, -1,                /* 98-9f */
  56         -1, -1, -1, -1, -1, -1, -1, -1,                /* a0-a7 */
  57         -1, -1, -1, -1, -1, -1, -1, -1,                /* a8-af */
  58         -1, -1, -1, -1, -1, -1, -1, -1,                /* b0-b7 */
  59         -1, -1, -1, -1, -1, -1, -1, -1,                /* b8-bf */
  60         -1, -1, -1, -1, -1, -1, -1, -1,                /* c0-c7 */
  61         -1, -1, -1, -1, -1, -1, -1, -1,                /* c8-cf */
  62         -1, -1, -1, -1, -1, -1, -1, -1,                /* d0-d7 */
  63         -1, -1, -1, -1, -1, -1, -1, -1,                /* d8-df */
  64         -1, -1, -1, -1, -1, -1, -1, -1,                /* e0-e7 */
  65         -1, -1, -1, -1, -1, -1, -1, -1,                /* e8-ef */
  66         -1, -1, -1, -1, -1, -1, -1, -1,                /* f0-f7 */
  67         -1, -1, -1, -1, -1, -1, -1, -1,                /* f8-ff */
  68};
  69
  70int get_sha1_hex(const char *hex, unsigned char *sha1)
  71{
  72        int i;
  73        for (i = 0; i < 20; i++) {
  74                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  75                if (val & ~0xff)
  76                        return -1;
  77                *sha1++ = val;
  78                hex += 2;
  79        }
  80        return 0;
  81}
  82
  83int safe_create_leading_directories(char *path)
  84{
  85        char *pos = path;
  86        struct stat st;
  87
  88        if (*pos == '/')
  89                pos++;
  90
  91        while (pos) {
  92                pos = strchr(pos, '/');
  93                if (!pos)
  94                        break;
  95                *pos = 0;
  96                if (!stat(path, &st)) {
  97                        /* path exists */
  98                        if (!S_ISDIR(st.st_mode)) {
  99                                *pos = '/';
 100                                return -3;
 101                        }
 102                }
 103                else if (mkdir(path, 0777)) {
 104                        *pos = '/';
 105                        return -1;
 106                }
 107                else if (adjust_shared_perm(path)) {
 108                        *pos = '/';
 109                        return -2;
 110                }
 111                *pos++ = '/';
 112        }
 113        return 0;
 114}
 115
 116char * sha1_to_hex(const unsigned char *sha1)
 117{
 118        static int bufno;
 119        static char hexbuffer[4][50];
 120        static const char hex[] = "0123456789abcdef";
 121        char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
 122        int i;
 123
 124        for (i = 0; i < 20; i++) {
 125                unsigned int val = *sha1++;
 126                *buf++ = hex[val >> 4];
 127                *buf++ = hex[val & 0xf];
 128        }
 129        *buf = '\0';
 130
 131        return buffer;
 132}
 133
 134static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 135{
 136        int i;
 137        for (i = 0; i < 20; i++) {
 138                static char hex[] = "0123456789abcdef";
 139                unsigned int val = sha1[i];
 140                char *pos = pathbuf + i*2 + (i > 0);
 141                *pos++ = hex[val >> 4];
 142                *pos = hex[val & 0xf];
 143        }
 144}
 145
 146/*
 147 * NOTE! This returns a statically allocated buffer, so you have to be
 148 * careful about using it. Do a "xstrdup()" if you need to save the
 149 * filename.
 150 *
 151 * Also note that this returns the location for creating.  Reading
 152 * SHA1 file can happen from any alternate directory listed in the
 153 * DB_ENVIRONMENT environment variable if it is not found in
 154 * the primary object database.
 155 */
 156char *sha1_file_name(const unsigned char *sha1)
 157{
 158        static char *name, *base;
 159
 160        if (!base) {
 161                const char *sha1_file_directory = get_object_directory();
 162                int len = strlen(sha1_file_directory);
 163                base = xmalloc(len + 60);
 164                memcpy(base, sha1_file_directory, len);
 165                memset(base+len, 0, 60);
 166                base[len] = '/';
 167                base[len+3] = '/';
 168                name = base + len + 1;
 169        }
 170        fill_sha1_path(name, sha1);
 171        return base;
 172}
 173
 174char *sha1_pack_name(const unsigned char *sha1)
 175{
 176        static const char hex[] = "0123456789abcdef";
 177        static char *name, *base, *buf;
 178        int i;
 179
 180        if (!base) {
 181                const char *sha1_file_directory = get_object_directory();
 182                int len = strlen(sha1_file_directory);
 183                base = xmalloc(len + 60);
 184                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 185                name = base + len + 11;
 186        }
 187
 188        buf = name;
 189
 190        for (i = 0; i < 20; i++) {
 191                unsigned int val = *sha1++;
 192                *buf++ = hex[val >> 4];
 193                *buf++ = hex[val & 0xf];
 194        }
 195        
 196        return base;
 197}
 198
 199char *sha1_pack_index_name(const unsigned char *sha1)
 200{
 201        static const char hex[] = "0123456789abcdef";
 202        static char *name, *base, *buf;
 203        int i;
 204
 205        if (!base) {
 206                const char *sha1_file_directory = get_object_directory();
 207                int len = strlen(sha1_file_directory);
 208                base = xmalloc(len + 60);
 209                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 210                name = base + len + 11;
 211        }
 212
 213        buf = name;
 214
 215        for (i = 0; i < 20; i++) {
 216                unsigned int val = *sha1++;
 217                *buf++ = hex[val >> 4];
 218                *buf++ = hex[val & 0xf];
 219        }
 220        
 221        return base;
 222}
 223
 224struct alternate_object_database *alt_odb_list;
 225static struct alternate_object_database **alt_odb_tail;
 226
 227static void read_info_alternates(const char * alternates, int depth);
 228
 229/*
 230 * Prepare alternate object database registry.
 231 *
 232 * The variable alt_odb_list points at the list of struct
 233 * alternate_object_database.  The elements on this list come from
 234 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 235 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 236 * whose contents is similar to that environment variable but can be
 237 * LF separated.  Its base points at a statically allocated buffer that
 238 * contains "/the/directory/corresponding/to/.git/objects/...", while
 239 * its name points just after the slash at the end of ".git/objects/"
 240 * in the example above, and has enough space to hold 40-byte hex
 241 * SHA1, an extra slash for the first level indirection, and the
 242 * terminating NUL.
 243 */
 244static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 245{
 246        struct stat st;
 247        const char *objdir = get_object_directory();
 248        struct alternate_object_database *ent;
 249        struct alternate_object_database *alt;
 250        /* 43 = 40-byte + 2 '/' + terminating NUL */
 251        int pfxlen = len;
 252        int entlen = pfxlen + 43;
 253        int base_len = -1;
 254
 255        if (*entry != '/' && relative_base) {
 256                /* Relative alt-odb */
 257                if (base_len < 0)
 258                        base_len = strlen(relative_base) + 1;
 259                entlen += base_len;
 260                pfxlen += base_len;
 261        }
 262        ent = xmalloc(sizeof(*ent) + entlen);
 263
 264        if (*entry != '/' && relative_base) {
 265                memcpy(ent->base, relative_base, base_len - 1);
 266                ent->base[base_len - 1] = '/';
 267                memcpy(ent->base + base_len, entry, len);
 268        }
 269        else
 270                memcpy(ent->base, entry, pfxlen);
 271
 272        ent->name = ent->base + pfxlen + 1;
 273        ent->base[pfxlen + 3] = '/';
 274        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 275
 276        /* Detect cases where alternate disappeared */
 277        if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 278                error("object directory %s does not exist; "
 279                      "check .git/objects/info/alternates.",
 280                      ent->base);
 281                free(ent);
 282                return -1;
 283        }
 284
 285        /* Prevent the common mistake of listing the same
 286         * thing twice, or object directory itself.
 287         */
 288        for (alt = alt_odb_list; alt; alt = alt->next) {
 289                if (!memcmp(ent->base, alt->base, pfxlen)) {
 290                        free(ent);
 291                        return -1;
 292                }
 293        }
 294        if (!memcmp(ent->base, objdir, pfxlen)) {
 295                free(ent);
 296                return -1;
 297        }
 298
 299        /* add the alternate entry */
 300        *alt_odb_tail = ent;
 301        alt_odb_tail = &(ent->next);
 302        ent->next = NULL;
 303
 304        /* recursively add alternates */
 305        read_info_alternates(ent->base, depth + 1);
 306
 307        ent->base[pfxlen] = '/';
 308
 309        return 0;
 310}
 311
 312static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 313                                 const char *relative_base, int depth)
 314{
 315        const char *cp, *last;
 316
 317        if (depth > 5) {
 318                error("%s: ignoring alternate object stores, nesting too deep.",
 319                                relative_base);
 320                return;
 321        }
 322
 323        last = alt;
 324        while (last < ep) {
 325                cp = last;
 326                if (cp < ep && *cp == '#') {
 327                        while (cp < ep && *cp != sep)
 328                                cp++;
 329                        last = cp + 1;
 330                        continue;
 331                }
 332                while (cp < ep && *cp != sep)
 333                        cp++;
 334                if (last != cp) {
 335                        if ((*last != '/') && depth) {
 336                                error("%s: ignoring relative alternate object store %s",
 337                                                relative_base, last);
 338                        } else {
 339                                link_alt_odb_entry(last, cp - last,
 340                                                relative_base, depth);
 341                        }
 342                }
 343                while (cp < ep && *cp == sep)
 344                        cp++;
 345                last = cp;
 346        }
 347}
 348
 349static void read_info_alternates(const char * relative_base, int depth)
 350{
 351        char *map;
 352        struct stat st;
 353        char path[PATH_MAX];
 354        int fd;
 355
 356        sprintf(path, "%s/info/alternates", relative_base);
 357        fd = open(path, O_RDONLY);
 358        if (fd < 0)
 359                return;
 360        if (fstat(fd, &st) || (st.st_size == 0)) {
 361                close(fd);
 362                return;
 363        }
 364        map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 365        close(fd);
 366
 367        link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
 368
 369        munmap(map, st.st_size);
 370}
 371
 372void prepare_alt_odb(void)
 373{
 374        const char *alt;
 375
 376        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 377        if (!alt) alt = "";
 378
 379        if (alt_odb_tail)
 380                return;
 381        alt_odb_tail = &alt_odb_list;
 382        link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 383
 384        read_info_alternates(get_object_directory(), 0);
 385}
 386
 387static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 388{
 389        char *name = sha1_file_name(sha1);
 390        struct alternate_object_database *alt;
 391
 392        if (!stat(name, st))
 393                return name;
 394        prepare_alt_odb();
 395        for (alt = alt_odb_list; alt; alt = alt->next) {
 396                name = alt->name;
 397                fill_sha1_path(name, sha1);
 398                if (!stat(alt->base, st))
 399                        return alt->base;
 400        }
 401        return NULL;
 402}
 403
 404static unsigned int pack_used_ctr;
 405static unsigned int pack_mmap_calls;
 406static unsigned int peak_pack_open_windows;
 407static unsigned int pack_open_windows;
 408static size_t peak_pack_mapped;
 409static size_t pack_mapped;
 410struct packed_git *packed_git;
 411
 412void pack_report()
 413{
 414        fprintf(stderr,
 415                "pack_report: getpagesize()            = %10" SZ_FMT "\n"
 416                "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 417                "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
 418                (size_t) getpagesize(),
 419                packed_git_window_size,
 420                packed_git_limit);
 421        fprintf(stderr,
 422                "pack_report: pack_used_ctr            = %10u\n"
 423                "pack_report: pack_mmap_calls          = %10u\n"
 424                "pack_report: pack_open_windows        = %10u / %10u\n"
 425                "pack_report: pack_mapped              = "
 426                        "%10" SZ_FMT " / %10" SZ_FMT "\n",
 427                pack_used_ctr,
 428                pack_mmap_calls,
 429                pack_open_windows, peak_pack_open_windows,
 430                pack_mapped, peak_pack_mapped);
 431}
 432
 433static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 434                                void **idx_map_)
 435{
 436        void *idx_map;
 437        uint32_t *index;
 438        unsigned long idx_size;
 439        int nr, i;
 440        int fd = open(path, O_RDONLY);
 441        struct stat st;
 442        if (fd < 0)
 443                return -1;
 444        if (fstat(fd, &st)) {
 445                close(fd);
 446                return -1;
 447        }
 448        idx_size = st.st_size;
 449        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 450        close(fd);
 451
 452        index = idx_map;
 453        *idx_map_ = idx_map;
 454        *idx_size_ = idx_size;
 455
 456        /* check index map */
 457        if (idx_size < 4*256 + 20 + 20)
 458                return error("index file %s is too small", path);
 459
 460        /* a future index format would start with this, as older git
 461         * binaries would fail the non-monotonic index check below.
 462         * give a nicer warning to the user if we can.
 463         */
 464        if (index[0] == htonl(PACK_IDX_SIGNATURE))
 465                return error("index file %s is a newer version"
 466                        " and is not supported by this binary"
 467                        " (try upgrading GIT to a newer version)",
 468                        path);
 469
 470        nr = 0;
 471        for (i = 0; i < 256; i++) {
 472                unsigned int n = ntohl(index[i]);
 473                if (n < nr)
 474                        return error("non-monotonic index %s", path);
 475                nr = n;
 476        }
 477
 478        /*
 479         * Total size:
 480         *  - 256 index entries 4 bytes each
 481         *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 482         *  - 20-byte SHA1 of the packfile
 483         *  - 20-byte SHA1 file checksum
 484         */
 485        if (idx_size != 4*256 + nr * 24 + 20 + 20)
 486                return error("wrong index file size in %s", path);
 487
 488        return 0;
 489}
 490
 491static void scan_windows(struct packed_git *p,
 492        struct packed_git **lru_p,
 493        struct pack_window **lru_w,
 494        struct pack_window **lru_l)
 495{
 496        struct pack_window *w, *w_l;
 497
 498        for (w_l = NULL, w = p->windows; w; w = w->next) {
 499                if (!w->inuse_cnt) {
 500                        if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 501                                *lru_p = p;
 502                                *lru_w = w;
 503                                *lru_l = w_l;
 504                        }
 505                }
 506                w_l = w;
 507        }
 508}
 509
 510static int unuse_one_window(struct packed_git *current)
 511{
 512        struct packed_git *p, *lru_p = NULL;
 513        struct pack_window *lru_w = NULL, *lru_l = NULL;
 514
 515        if (current)
 516                scan_windows(current, &lru_p, &lru_w, &lru_l);
 517        for (p = packed_git; p; p = p->next)
 518                scan_windows(p, &lru_p, &lru_w, &lru_l);
 519        if (lru_p) {
 520                munmap(lru_w->base, lru_w->len);
 521                pack_mapped -= lru_w->len;
 522                if (lru_l)
 523                        lru_l->next = lru_w->next;
 524                else {
 525                        lru_p->windows = lru_w->next;
 526                        if (!lru_p->windows && lru_p != current) {
 527                                close(lru_p->pack_fd);
 528                                lru_p->pack_fd = -1;
 529                        }
 530                }
 531                free(lru_w);
 532                pack_open_windows--;
 533                return 1;
 534        }
 535        return 0;
 536}
 537
 538void release_pack_memory(size_t need)
 539{
 540        size_t cur = pack_mapped;
 541        while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 542                ; /* nothing */
 543}
 544
 545void unuse_pack(struct pack_window **w_cursor)
 546{
 547        struct pack_window *w = *w_cursor;
 548        if (w) {
 549                w->inuse_cnt--;
 550                *w_cursor = NULL;
 551        }
 552}
 553
 554/*
 555 * Do not call this directly as this leaks p->pack_fd on error return;
 556 * call open_packed_git() instead.
 557 */
 558static int open_packed_git_1(struct packed_git *p)
 559{
 560        struct stat st;
 561        struct pack_header hdr;
 562        unsigned char sha1[20];
 563        unsigned char *idx_sha1;
 564        long fd_flag;
 565
 566        p->pack_fd = open(p->pack_name, O_RDONLY);
 567        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 568                return -1;
 569
 570        /* If we created the struct before we had the pack we lack size. */
 571        if (!p->pack_size) {
 572                if (!S_ISREG(st.st_mode))
 573                        return error("packfile %s not a regular file", p->pack_name);
 574                p->pack_size = st.st_size;
 575        } else if (p->pack_size != st.st_size)
 576                return error("packfile %s size changed", p->pack_name);
 577
 578        /* We leave these file descriptors open with sliding mmap;
 579         * there is no point keeping them open across exec(), though.
 580         */
 581        fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 582        if (fd_flag < 0)
 583                return error("cannot determine file descriptor flags");
 584        fd_flag |= FD_CLOEXEC;
 585        if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 586                return error("cannot set FD_CLOEXEC");
 587
 588        /* Verify we recognize this pack file format. */
 589        if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 590                return error("file %s is far too short to be a packfile", p->pack_name);
 591        if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 592                return error("file %s is not a GIT packfile", p->pack_name);
 593        if (!pack_version_ok(hdr.hdr_version))
 594                return error("packfile %s is version %u and not supported"
 595                        " (try upgrading GIT to a newer version)",
 596                        p->pack_name, ntohl(hdr.hdr_version));
 597
 598        /* Verify the pack matches its index. */
 599        if (num_packed_objects(p) != ntohl(hdr.hdr_entries))
 600                return error("packfile %s claims to have %u objects"
 601                        " while index size indicates %u objects",
 602                        p->pack_name, ntohl(hdr.hdr_entries),
 603                        num_packed_objects(p));
 604        if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
 605                return error("end of packfile %s is unavailable", p->pack_name);
 606        if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
 607                return error("packfile %s signature is unavailable", p->pack_name);
 608        idx_sha1 = ((unsigned char *)p->index_base) + p->index_size - 40;
 609        if (hashcmp(sha1, idx_sha1))
 610                return error("packfile %s does not match index", p->pack_name);
 611        return 0;
 612}
 613
 614static int open_packed_git(struct packed_git *p)
 615{
 616        if (!open_packed_git_1(p))
 617                return 0;
 618        if (p->pack_fd != -1) {
 619                close(p->pack_fd);
 620                p->pack_fd = -1;
 621        }
 622        return -1;
 623}
 624
 625static int in_window(struct pack_window *win, unsigned long offset)
 626{
 627        /* We must promise at least 20 bytes (one hash) after the
 628         * offset is available from this window, otherwise the offset
 629         * is not actually in this window and a different window (which
 630         * has that one hash excess) must be used.  This is to support
 631         * the object header and delta base parsing routines below.
 632         */
 633        off_t win_off = win->offset;
 634        return win_off <= offset
 635                && (offset + 20) <= (win_off + win->len);
 636}
 637
 638unsigned char* use_pack(struct packed_git *p,
 639                struct pack_window **w_cursor,
 640                unsigned long offset,
 641                unsigned int *left)
 642{
 643        struct pack_window *win = *w_cursor;
 644
 645        if (p->pack_fd == -1 && open_packed_git(p))
 646                die("packfile %s cannot be accessed", p->pack_name);
 647
 648        /* Since packfiles end in a hash of their content and its
 649         * pointless to ask for an offset into the middle of that
 650         * hash, and the in_window function above wouldn't match
 651         * don't allow an offset too close to the end of the file.
 652         */
 653        if (offset > (p->pack_size - 20))
 654                die("offset beyond end of packfile (truncated pack?)");
 655
 656        if (!win || !in_window(win, offset)) {
 657                if (win)
 658                        win->inuse_cnt--;
 659                for (win = p->windows; win; win = win->next) {
 660                        if (in_window(win, offset))
 661                                break;
 662                }
 663                if (!win) {
 664                        size_t window_align = packed_git_window_size / 2;
 665                        win = xcalloc(1, sizeof(*win));
 666                        win->offset = (offset / window_align) * window_align;
 667                        win->len = p->pack_size - win->offset;
 668                        if (win->len > packed_git_window_size)
 669                                win->len = packed_git_window_size;
 670                        pack_mapped += win->len;
 671                        while (packed_git_limit < pack_mapped
 672                                && unuse_one_window(p))
 673                                ; /* nothing */
 674                        win->base = xmmap(NULL, win->len,
 675                                PROT_READ, MAP_PRIVATE,
 676                                p->pack_fd, win->offset);
 677                        if (win->base == MAP_FAILED)
 678                                die("packfile %s cannot be mapped: %s",
 679                                        p->pack_name,
 680                                        strerror(errno));
 681                        pack_mmap_calls++;
 682                        pack_open_windows++;
 683                        if (pack_mapped > peak_pack_mapped)
 684                                peak_pack_mapped = pack_mapped;
 685                        if (pack_open_windows > peak_pack_open_windows)
 686                                peak_pack_open_windows = pack_open_windows;
 687                        win->next = p->windows;
 688                        p->windows = win;
 689                }
 690        }
 691        if (win != *w_cursor) {
 692                win->last_used = pack_used_ctr++;
 693                win->inuse_cnt++;
 694                *w_cursor = win;
 695        }
 696        offset -= win->offset;
 697        if (left)
 698                *left = win->len - offset;
 699        return win->base + offset;
 700}
 701
 702struct packed_git *add_packed_git(char *path, int path_len, int local)
 703{
 704        struct stat st;
 705        struct packed_git *p;
 706        unsigned long idx_size;
 707        void *idx_map;
 708        unsigned char sha1[20];
 709
 710        if (check_packed_git_idx(path, &idx_size, &idx_map))
 711                return NULL;
 712
 713        /* do we have a corresponding .pack file? */
 714        strcpy(path + path_len - 4, ".pack");
 715        if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 716                munmap(idx_map, idx_size);
 717                return NULL;
 718        }
 719        /* ok, it looks sane as far as we can check without
 720         * actually mapping the pack file.
 721         */
 722        p = xmalloc(sizeof(*p) + path_len + 2);
 723        strcpy(p->pack_name, path);
 724        p->index_size = idx_size;
 725        p->pack_size = st.st_size;
 726        p->index_base = idx_map;
 727        p->next = NULL;
 728        p->windows = NULL;
 729        p->pack_fd = -1;
 730        p->pack_local = local;
 731        if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 732                hashcpy(p->sha1, sha1);
 733        return p;
 734}
 735
 736struct packed_git *parse_pack_index(unsigned char *sha1)
 737{
 738        char *path = sha1_pack_index_name(sha1);
 739        return parse_pack_index_file(sha1, path);
 740}
 741
 742struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 743{
 744        struct packed_git *p;
 745        unsigned long idx_size;
 746        void *idx_map;
 747        char *path;
 748
 749        if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 750                return NULL;
 751
 752        path = sha1_pack_name(sha1);
 753
 754        p = xmalloc(sizeof(*p) + strlen(path) + 2);
 755        strcpy(p->pack_name, path);
 756        p->index_size = idx_size;
 757        p->pack_size = 0;
 758        p->index_base = idx_map;
 759        p->next = NULL;
 760        p->windows = NULL;
 761        p->pack_fd = -1;
 762        hashcpy(p->sha1, sha1);
 763        return p;
 764}
 765
 766void install_packed_git(struct packed_git *pack)
 767{
 768        pack->next = packed_git;
 769        packed_git = pack;
 770}
 771
 772static void prepare_packed_git_one(char *objdir, int local)
 773{
 774        char path[PATH_MAX];
 775        int len;
 776        DIR *dir;
 777        struct dirent *de;
 778
 779        sprintf(path, "%s/pack", objdir);
 780        len = strlen(path);
 781        dir = opendir(path);
 782        if (!dir) {
 783                if (errno != ENOENT)
 784                        error("unable to open object pack directory: %s: %s",
 785                              path, strerror(errno));
 786                return;
 787        }
 788        path[len++] = '/';
 789        while ((de = readdir(dir)) != NULL) {
 790                int namelen = strlen(de->d_name);
 791                struct packed_git *p;
 792
 793                if (!has_extension(de->d_name, ".idx"))
 794                        continue;
 795
 796                /* Don't reopen a pack we already have. */
 797                strcpy(path + len, de->d_name);
 798                for (p = packed_git; p; p = p->next) {
 799                        if (!memcmp(path, p->pack_name, len + namelen - 4))
 800                                break;
 801                }
 802                if (p)
 803                        continue;
 804                /* See if it really is a valid .idx file with corresponding
 805                 * .pack file that we can map.
 806                 */
 807                p = add_packed_git(path, len + namelen, local);
 808                if (!p)
 809                        continue;
 810                install_packed_git(p);
 811        }
 812        closedir(dir);
 813}
 814
 815static int prepare_packed_git_run_once = 0;
 816void prepare_packed_git(void)
 817{
 818        struct alternate_object_database *alt;
 819
 820        if (prepare_packed_git_run_once)
 821                return;
 822        prepare_packed_git_one(get_object_directory(), 1);
 823        prepare_alt_odb();
 824        for (alt = alt_odb_list; alt; alt = alt->next) {
 825                alt->name[-1] = 0;
 826                prepare_packed_git_one(alt->base, 0);
 827                alt->name[-1] = '/';
 828        }
 829        prepare_packed_git_run_once = 1;
 830}
 831
 832void reprepare_packed_git(void)
 833{
 834        prepare_packed_git_run_once = 0;
 835        prepare_packed_git();
 836}
 837
 838int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 839{
 840        unsigned char real_sha1[20];
 841        hash_sha1_file(map, size, type, real_sha1);
 842        return hashcmp(sha1, real_sha1) ? -1 : 0;
 843}
 844
 845void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 846{
 847        struct stat st;
 848        void *map;
 849        int fd;
 850        char *filename = find_sha1_file(sha1, &st);
 851
 852        if (!filename) {
 853                return NULL;
 854        }
 855
 856        fd = open(filename, O_RDONLY | sha1_file_open_flag);
 857        if (fd < 0) {
 858                /* See if it works without O_NOATIME */
 859                switch (sha1_file_open_flag) {
 860                default:
 861                        fd = open(filename, O_RDONLY);
 862                        if (fd >= 0)
 863                                break;
 864                /* Fallthrough */
 865                case 0:
 866                        return NULL;
 867                }
 868
 869                /* If it failed once, it will probably fail again.
 870                 * Stop using O_NOATIME
 871                 */
 872                sha1_file_open_flag = 0;
 873        }
 874        map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 875        close(fd);
 876        *size = st.st_size;
 877        return map;
 878}
 879
 880int legacy_loose_object(unsigned char *map)
 881{
 882        unsigned int word;
 883
 884        /*
 885         * Is it a zlib-compressed buffer? If so, the first byte
 886         * must be 0x78 (15-bit window size, deflated), and the
 887         * first 16-bit word is evenly divisible by 31
 888         */
 889        word = (map[0] << 8) + map[1];
 890        if (map[0] == 0x78 && !(word % 31))
 891                return 1;
 892        else
 893                return 0;
 894}
 895
 896unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
 897{
 898        unsigned shift;
 899        unsigned char c;
 900        unsigned long size;
 901        unsigned long used = 0;
 902
 903        c = buf[used++];
 904        *type = (c >> 4) & 7;
 905        size = c & 15;
 906        shift = 4;
 907        while (c & 0x80) {
 908                if (len <= used)
 909                        return 0;
 910                if (sizeof(long) * 8 <= shift)
 911                        return 0;
 912                c = buf[used++];
 913                size += (c & 0x7f) << shift;
 914                shift += 7;
 915        }
 916        *sizep = size;
 917        return used;
 918}
 919
 920static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 921{
 922        unsigned long size, used;
 923        static const char valid_loose_object_type[8] = {
 924                0, /* OBJ_EXT */
 925                1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
 926                0, /* "delta" and others are invalid in a loose object */
 927        };
 928        enum object_type type;
 929
 930        /* Get the data stream */
 931        memset(stream, 0, sizeof(*stream));
 932        stream->next_in = map;
 933        stream->avail_in = mapsize;
 934        stream->next_out = buffer;
 935        stream->avail_out = bufsiz;
 936
 937        if (legacy_loose_object(map)) {
 938                inflateInit(stream);
 939                return inflate(stream, 0);
 940        }
 941
 942        used = unpack_object_header_gently(map, mapsize, &type, &size);
 943        if (!used || !valid_loose_object_type[type])
 944                return -1;
 945        map += used;
 946        mapsize -= used;
 947
 948        /* Set up the stream for the rest.. */
 949        stream->next_in = map;
 950        stream->avail_in = mapsize;
 951        inflateInit(stream);
 952
 953        /* And generate the fake traditional header */
 954        stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
 955                                         typename(type), size);
 956        return 0;
 957}
 958
 959static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 960{
 961        int bytes = strlen(buffer) + 1;
 962        unsigned char *buf = xmalloc(1+size);
 963        unsigned long n;
 964
 965        n = stream->total_out - bytes;
 966        if (n > size)
 967                n = size;
 968        memcpy(buf, (char *) buffer + bytes, n);
 969        bytes = n;
 970        if (bytes < size) {
 971                stream->next_out = buf + bytes;
 972                stream->avail_out = size - bytes;
 973                while (inflate(stream, Z_FINISH) == Z_OK)
 974                        /* nothing */;
 975        }
 976        buf[size] = 0;
 977        inflateEnd(stream);
 978        return buf;
 979}
 980
 981/*
 982 * We used to just use "sscanf()", but that's actually way
 983 * too permissive for what we want to check. So do an anal
 984 * object header parse by hand.
 985 */
 986static int parse_sha1_header(const char *hdr, unsigned long *sizep)
 987{
 988        char type[10];
 989        int i;
 990        unsigned long size;
 991
 992        /*
 993         * The type can be at most ten bytes (including the 
 994         * terminating '\0' that we add), and is followed by
 995         * a space.
 996         */
 997        i = 0;
 998        for (;;) {
 999                char c = *hdr++;
1000                if (c == ' ')
1001                        break;
1002                type[i++] = c;
1003                if (i >= sizeof(type))
1004                        return -1;
1005        }
1006        type[i] = 0;
1007
1008        /*
1009         * The length must follow immediately, and be in canonical
1010         * decimal format (ie "010" is not valid).
1011         */
1012        size = *hdr++ - '0';
1013        if (size > 9)
1014                return -1;
1015        if (size) {
1016                for (;;) {
1017                        unsigned long c = *hdr - '0';
1018                        if (c > 9)
1019                                break;
1020                        hdr++;
1021                        size = size * 10 + c;
1022                }
1023        }
1024        *sizep = size;
1025
1026        /*
1027         * The length must be followed by a zero byte
1028         */
1029        return *hdr ? -1 : type_from_string(type);
1030}
1031
1032void * unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size)
1033{
1034        int ret;
1035        z_stream stream;
1036        char hdr[8192];
1037
1038        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1039        if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1040                return NULL;
1041
1042        return unpack_sha1_rest(&stream, hdr, *size);
1043}
1044
1045static unsigned long get_delta_base(struct packed_git *p,
1046                                    struct pack_window **w_curs,
1047                                    unsigned long *curpos,
1048                                    enum object_type type,
1049                                    unsigned long delta_obj_offset)
1050{
1051        unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1052        unsigned long base_offset;
1053
1054        /* use_pack() assured us we have [base_info, base_info + 20)
1055         * as a range that we can look at without walking off the
1056         * end of the mapped window.  Its actually the hash size
1057         * that is assured.  An OFS_DELTA longer than the hash size
1058         * is stupid, as then a REF_DELTA would be smaller to store.
1059         */
1060        if (type == OBJ_OFS_DELTA) {
1061                unsigned used = 0;
1062                unsigned char c = base_info[used++];
1063                base_offset = c & 127;
1064                while (c & 128) {
1065                        base_offset += 1;
1066                        if (!base_offset || base_offset & ~(~0UL >> 7))
1067                                die("offset value overflow for delta base object");
1068                        c = base_info[used++];
1069                        base_offset = (base_offset << 7) + (c & 127);
1070                }
1071                base_offset = delta_obj_offset - base_offset;
1072                if (base_offset >= delta_obj_offset)
1073                        die("delta base offset out of bound");
1074                *curpos += used;
1075        } else if (type == OBJ_REF_DELTA) {
1076                /* The base entry _must_ be in the same pack */
1077                base_offset = find_pack_entry_one(base_info, p);
1078                if (!base_offset)
1079                        die("failed to find delta-pack base object %s",
1080                                sha1_to_hex(base_info));
1081                *curpos += 20;
1082        } else
1083                die("I am totally screwed");
1084        return base_offset;
1085}
1086
1087/* forward declaration for a mutually recursive function */
1088static int packed_object_info(struct packed_git *p, unsigned long offset,
1089                              unsigned long *sizep);
1090
1091static int packed_delta_info(struct packed_git *p,
1092                             struct pack_window **w_curs,
1093                             unsigned long curpos,
1094                             enum object_type type,
1095                             unsigned long obj_offset,
1096                             unsigned long *sizep)
1097{
1098        unsigned long base_offset;
1099
1100        base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1101        type = packed_object_info(p, base_offset, NULL);
1102
1103        /* We choose to only get the type of the base object and
1104         * ignore potentially corrupt pack file that expects the delta
1105         * based on a base with a wrong size.  This saves tons of
1106         * inflate() calls.
1107         */
1108        if (sizep) {
1109                const unsigned char *data;
1110                unsigned char delta_head[20], *in;
1111                z_stream stream;
1112                int st;
1113
1114                memset(&stream, 0, sizeof(stream));
1115                stream.next_out = delta_head;
1116                stream.avail_out = sizeof(delta_head);
1117
1118                inflateInit(&stream);
1119                do {
1120                        in = use_pack(p, w_curs, curpos, &stream.avail_in);
1121                        stream.next_in = in;
1122                        st = inflate(&stream, Z_FINISH);
1123                        curpos += stream.next_in - in;
1124                } while ((st == Z_OK || st == Z_BUF_ERROR)
1125                        && stream.total_out < sizeof(delta_head));
1126                inflateEnd(&stream);
1127                if ((st != Z_STREAM_END) &&
1128                    stream.total_out != sizeof(delta_head))
1129                        die("delta data unpack-initial failed");
1130
1131                /* Examine the initial part of the delta to figure out
1132                 * the result size.
1133                 */
1134                data = delta_head;
1135
1136                /* ignore base size */
1137                get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1138
1139                /* Read the result size */
1140                *sizep = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1141        }
1142
1143        return type;
1144}
1145
1146static int unpack_object_header(struct packed_git *p,
1147                                struct pack_window **w_curs,
1148                                unsigned long *curpos,
1149                                unsigned long *sizep)
1150{
1151        unsigned char *base;
1152        unsigned int left;
1153        unsigned long used;
1154        enum object_type type;
1155
1156        /* use_pack() assures us we have [base, base + 20) available
1157         * as a range that we can look at at.  (Its actually the hash
1158         * size that is assured.)  With our object header encoding
1159         * the maximum deflated object size is 2^137, which is just
1160         * insane, so we know won't exceed what we have been given.
1161         */
1162        base = use_pack(p, w_curs, *curpos, &left);
1163        used = unpack_object_header_gently(base, left, &type, sizep);
1164        if (!used)
1165                die("object offset outside of pack file");
1166        *curpos += used;
1167
1168        return type;
1169}
1170
1171const char *packed_object_info_detail(struct packed_git *p,
1172                                      unsigned long obj_offset,
1173                                      unsigned long *size,
1174                                      unsigned long *store_size,
1175                                      unsigned int *delta_chain_length,
1176                                      unsigned char *base_sha1)
1177{
1178        struct pack_window *w_curs = NULL;
1179        unsigned long curpos, dummy;
1180        unsigned char *next_sha1;
1181        enum object_type type;
1182
1183        *delta_chain_length = 0;
1184        curpos = obj_offset;
1185        type = unpack_object_header(p, &w_curs, &curpos, size);
1186
1187        for (;;) {
1188                switch (type) {
1189                default:
1190                        die("pack %s contains unknown object type %d",
1191                            p->pack_name, type);
1192                case OBJ_COMMIT:
1193                case OBJ_TREE:
1194                case OBJ_BLOB:
1195                case OBJ_TAG:
1196                        *store_size = 0; /* notyet */
1197                        unuse_pack(&w_curs);
1198                        return typename(type);
1199                case OBJ_OFS_DELTA:
1200                        obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1201                        if (*delta_chain_length == 0) {
1202                                /* TODO: find base_sha1 as pointed by curpos */
1203                        }
1204                        break;
1205                case OBJ_REF_DELTA:
1206                        next_sha1 = use_pack(p, &w_curs, curpos, NULL);
1207                        if (*delta_chain_length == 0)
1208                                hashcpy(base_sha1, next_sha1);
1209                        obj_offset = find_pack_entry_one(next_sha1, p);
1210                        break;
1211                }
1212                (*delta_chain_length)++;
1213                curpos = obj_offset;
1214                type = unpack_object_header(p, &w_curs, &curpos, &dummy);
1215        }
1216}
1217
1218static int packed_object_info(struct packed_git *p, unsigned long obj_offset,
1219                              unsigned long *sizep)
1220{
1221        struct pack_window *w_curs = NULL;
1222        unsigned long size, curpos = obj_offset;
1223        enum object_type type;
1224
1225        type = unpack_object_header(p, &w_curs, &curpos, &size);
1226
1227        switch (type) {
1228        case OBJ_OFS_DELTA:
1229        case OBJ_REF_DELTA:
1230                type = packed_delta_info(p, &w_curs, curpos,
1231                                         type, obj_offset, sizep);
1232                break;
1233        case OBJ_COMMIT:
1234        case OBJ_TREE:
1235        case OBJ_BLOB:
1236        case OBJ_TAG:
1237                if (sizep)
1238                        *sizep = size;
1239                break;
1240        default:
1241                die("pack %s contains unknown object type %d",
1242                    p->pack_name, type);
1243        }
1244        unuse_pack(&w_curs);
1245        return type;
1246}
1247
1248static void *unpack_compressed_entry(struct packed_git *p,
1249                                    struct pack_window **w_curs,
1250                                    unsigned long curpos,
1251                                    unsigned long size)
1252{
1253        int st;
1254        z_stream stream;
1255        unsigned char *buffer, *in;
1256
1257        buffer = xmalloc(size + 1);
1258        buffer[size] = 0;
1259        memset(&stream, 0, sizeof(stream));
1260        stream.next_out = buffer;
1261        stream.avail_out = size;
1262
1263        inflateInit(&stream);
1264        do {
1265                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1266                stream.next_in = in;
1267                st = inflate(&stream, Z_FINISH);
1268                curpos += stream.next_in - in;
1269        } while (st == Z_OK || st == Z_BUF_ERROR);
1270        inflateEnd(&stream);
1271        if ((st != Z_STREAM_END) || stream.total_out != size) {
1272                free(buffer);
1273                return NULL;
1274        }
1275
1276        return buffer;
1277}
1278
1279static void *unpack_delta_entry(struct packed_git *p,
1280                                struct pack_window **w_curs,
1281                                unsigned long curpos,
1282                                unsigned long delta_size,
1283                                unsigned long obj_offset,
1284                                enum object_type *type,
1285                                unsigned long *sizep)
1286{
1287        void *delta_data, *result, *base;
1288        unsigned long base_size, base_offset;
1289
1290        base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
1291        base = unpack_entry(p, base_offset, type, &base_size);
1292        if (!base)
1293                die("failed to read delta base object at %lu from %s",
1294                    base_offset, p->pack_name);
1295
1296        delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
1297        result = patch_delta(base, base_size,
1298                             delta_data, delta_size,
1299                             sizep);
1300        if (!result)
1301                die("failed to apply delta");
1302        free(delta_data);
1303        free(base);
1304        return result;
1305}
1306
1307void *unpack_entry(struct packed_git *p, unsigned long obj_offset,
1308                   enum object_type *type, unsigned long *sizep)
1309{
1310        struct pack_window *w_curs = NULL;
1311        unsigned long curpos = obj_offset;
1312        void *data;
1313
1314        *type = unpack_object_header(p, &w_curs, &curpos, sizep);
1315        switch (*type) {
1316        case OBJ_OFS_DELTA:
1317        case OBJ_REF_DELTA:
1318                data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
1319                                          obj_offset, type, sizep);
1320                break;
1321        case OBJ_COMMIT:
1322        case OBJ_TREE:
1323        case OBJ_BLOB:
1324        case OBJ_TAG:
1325                data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
1326                break;
1327        default:
1328                die("unknown object type %i in %s", *type, p->pack_name);
1329        }
1330        unuse_pack(&w_curs);
1331        return data;
1332}
1333
1334int num_packed_objects(const struct packed_git *p)
1335{
1336        /* See check_packed_git_idx() */
1337        return (p->index_size - 20 - 20 - 4*256) / 24;
1338}
1339
1340int nth_packed_object_sha1(const struct packed_git *p, int n,
1341                           unsigned char* sha1)
1342{
1343        void *index = p->index_base + 256;
1344        if (n < 0 || num_packed_objects(p) <= n)
1345                return -1;
1346        hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
1347        return 0;
1348}
1349
1350unsigned long find_pack_entry_one(const unsigned char *sha1,
1351                                  struct packed_git *p)
1352{
1353        uint32_t *level1_ofs = p->index_base;
1354        int hi = ntohl(level1_ofs[*sha1]);
1355        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1356        void *index = p->index_base + 256;
1357
1358        do {
1359                int mi = (lo + hi) / 2;
1360                int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
1361                if (!cmp)
1362                        return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
1363                if (cmp > 0)
1364                        hi = mi;
1365                else
1366                        lo = mi+1;
1367        } while (lo < hi);
1368        return 0;
1369}
1370
1371static int matches_pack_name(struct packed_git *p, const char *ig)
1372{
1373        const char *last_c, *c;
1374
1375        if (!strcmp(p->pack_name, ig))
1376                return 0;
1377
1378        for (c = p->pack_name, last_c = c; *c;)
1379                if (*c == '/')
1380                        last_c = ++c;
1381                else
1382                        ++c;
1383        if (!strcmp(last_c, ig))
1384                return 0;
1385
1386        return 1;
1387}
1388
1389static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
1390{
1391        struct packed_git *p;
1392        unsigned long offset;
1393
1394        prepare_packed_git();
1395
1396        for (p = packed_git; p; p = p->next) {
1397                if (ignore_packed) {
1398                        const char **ig;
1399                        for (ig = ignore_packed; *ig; ig++)
1400                                if (!matches_pack_name(p, *ig))
1401                                        break;
1402                        if (*ig)
1403                                continue;
1404                }
1405                offset = find_pack_entry_one(sha1, p);
1406                if (offset) {
1407                        /*
1408                         * We are about to tell the caller where they can
1409                         * locate the requested object.  We better make
1410                         * sure the packfile is still here and can be
1411                         * accessed before supplying that answer, as
1412                         * it may have been deleted since the index
1413                         * was loaded!
1414                         */
1415                        if (p->pack_fd == -1 && open_packed_git(p)) {
1416                                error("packfile %s cannot be accessed", p->pack_name);
1417                                continue;
1418                        }
1419                        e->offset = offset;
1420                        e->p = p;
1421                        hashcpy(e->sha1, sha1);
1422                        return 1;
1423                }
1424        }
1425        return 0;
1426}
1427
1428struct packed_git *find_sha1_pack(const unsigned char *sha1, 
1429                                  struct packed_git *packs)
1430{
1431        struct packed_git *p;
1432
1433        for (p = packs; p; p = p->next) {
1434                if (find_pack_entry_one(sha1, p))
1435                        return p;
1436        }
1437        return NULL;
1438
1439}
1440
1441static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
1442{
1443        int status;
1444        unsigned long mapsize, size;
1445        void *map;
1446        z_stream stream;
1447        char hdr[32];
1448
1449        map = map_sha1_file(sha1, &mapsize);
1450        if (!map)
1451                return error("unable to find %s", sha1_to_hex(sha1));
1452        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1453                status = error("unable to unpack %s header",
1454                               sha1_to_hex(sha1));
1455        else if ((status = parse_sha1_header(hdr, &size)) < 0)
1456                status = error("unable to parse %s header", sha1_to_hex(sha1));
1457        else if (sizep)
1458                *sizep = size;
1459        inflateEnd(&stream);
1460        munmap(map, mapsize);
1461        return status;
1462}
1463
1464int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1465{
1466        struct pack_entry e;
1467
1468        if (!find_pack_entry(sha1, &e, NULL)) {
1469                reprepare_packed_git();
1470                if (!find_pack_entry(sha1, &e, NULL))
1471                        return sha1_loose_object_info(sha1, sizep);
1472        }
1473        return packed_object_info(e.p, e.offset, sizep);
1474}
1475
1476static void *read_packed_sha1(const unsigned char *sha1,
1477                              enum object_type *type, unsigned long *size)
1478{
1479        struct pack_entry e;
1480
1481        if (!find_pack_entry(sha1, &e, NULL))
1482                return NULL;
1483        else
1484                return unpack_entry(e.p, e.offset, type, size);
1485}
1486
1487/*
1488 * This is meant to hold a *small* number of objects that you would
1489 * want read_sha1_file() to be able to return, but yet you do not want
1490 * to write them into the object store (e.g. a browse-only
1491 * application).
1492 */
1493static struct cached_object {
1494        unsigned char sha1[20];
1495        enum object_type type;
1496        void *buf;
1497        unsigned long size;
1498} *cached_objects;
1499static int cached_object_nr, cached_object_alloc;
1500
1501static struct cached_object *find_cached_object(const unsigned char *sha1)
1502{
1503        int i;
1504        struct cached_object *co = cached_objects;
1505
1506        for (i = 0; i < cached_object_nr; i++, co++) {
1507                if (!hashcmp(co->sha1, sha1))
1508                        return co;
1509        }
1510        return NULL;
1511}
1512
1513int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1514                      unsigned char *sha1)
1515{
1516        struct cached_object *co;
1517
1518        hash_sha1_file(buf, len, typename(type), sha1);
1519        if (has_sha1_file(sha1) || find_cached_object(sha1))
1520                return 0;
1521        if (cached_object_alloc <= cached_object_nr) {
1522                cached_object_alloc = alloc_nr(cached_object_alloc);
1523                cached_objects = xrealloc(cached_objects,
1524                                          sizeof(*cached_objects) *
1525                                          cached_object_alloc);
1526        }
1527        co = &cached_objects[cached_object_nr++];
1528        co->size = len;
1529        co->type = type;
1530        co->buf = xmalloc(len);
1531        memcpy(co->buf, buf, len);
1532        hashcpy(co->sha1, sha1);
1533        return 0;
1534}
1535
1536void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
1537                     unsigned long *size)
1538{
1539        unsigned long mapsize;
1540        void *map, *buf;
1541        struct cached_object *co;
1542
1543        co = find_cached_object(sha1);
1544        if (co) {
1545                buf = xmalloc(co->size + 1);
1546                memcpy(buf, co->buf, co->size);
1547                ((char*)buf)[co->size] = 0;
1548                *type = co->type;
1549                *size = co->size;
1550                return buf;
1551        }
1552
1553        buf = read_packed_sha1(sha1, type, size);
1554        if (buf)
1555                return buf;
1556        map = map_sha1_file(sha1, &mapsize);
1557        if (map) {
1558                buf = unpack_sha1_file(map, mapsize, type, size);
1559                munmap(map, mapsize);
1560                return buf;
1561        }
1562        reprepare_packed_git();
1563        return read_packed_sha1(sha1, type, size);
1564}
1565
1566void *read_object_with_reference(const unsigned char *sha1,
1567                                 const char *required_type_name,
1568                                 unsigned long *size,
1569                                 unsigned char *actual_sha1_return)
1570{
1571        enum object_type type, required_type;
1572        void *buffer;
1573        unsigned long isize;
1574        unsigned char actual_sha1[20];
1575
1576        required_type = type_from_string(required_type_name);
1577        hashcpy(actual_sha1, sha1);
1578        while (1) {
1579                int ref_length = -1;
1580                const char *ref_type = NULL;
1581
1582                buffer = read_sha1_file(actual_sha1, &type, &isize);
1583                if (!buffer)
1584                        return NULL;
1585                if (type == required_type) {
1586                        *size = isize;
1587                        if (actual_sha1_return)
1588                                hashcpy(actual_sha1_return, actual_sha1);
1589                        return buffer;
1590                }
1591                /* Handle references */
1592                else if (type == OBJ_COMMIT)
1593                        ref_type = "tree ";
1594                else if (type == OBJ_TAG)
1595                        ref_type = "object ";
1596                else {
1597                        free(buffer);
1598                        return NULL;
1599                }
1600                ref_length = strlen(ref_type);
1601
1602                if (memcmp(buffer, ref_type, ref_length) ||
1603                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1604                        free(buffer);
1605                        return NULL;
1606                }
1607                free(buffer);
1608                /* Now we have the ID of the referred-to object in
1609                 * actual_sha1.  Check again. */
1610        }
1611}
1612
1613static void write_sha1_file_prepare(void *buf, unsigned long len,
1614                                    const char *type, unsigned char *sha1,
1615                                    char *hdr, int *hdrlen)
1616{
1617        SHA_CTX c;
1618
1619        /* Generate the header */
1620        *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
1621
1622        /* Sha1.. */
1623        SHA1_Init(&c);
1624        SHA1_Update(&c, hdr, *hdrlen);
1625        SHA1_Update(&c, buf, len);
1626        SHA1_Final(sha1, &c);
1627}
1628
1629/*
1630 * Link the tempfile to the final place, possibly creating the
1631 * last directory level as you do so.
1632 *
1633 * Returns the errno on failure, 0 on success.
1634 */
1635static int link_temp_to_file(const char *tmpfile, const char *filename)
1636{
1637        int ret;
1638        char *dir;
1639
1640        if (!link(tmpfile, filename))
1641                return 0;
1642
1643        /*
1644         * Try to mkdir the last path component if that failed.
1645         *
1646         * Re-try the "link()" regardless of whether the mkdir
1647         * succeeds, since a race might mean that somebody
1648         * else succeeded.
1649         */
1650        ret = errno;
1651        dir = strrchr(filename, '/');
1652        if (dir) {
1653                *dir = 0;
1654                if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
1655                        *dir = '/';
1656                        return -2;
1657                }
1658                *dir = '/';
1659                if (!link(tmpfile, filename))
1660                        return 0;
1661                ret = errno;
1662        }
1663        return ret;
1664}
1665
1666/*
1667 * Move the just written object into its final resting place
1668 */
1669int move_temp_to_file(const char *tmpfile, const char *filename)
1670{
1671        int ret = link_temp_to_file(tmpfile, filename);
1672
1673        /*
1674         * Coda hack - coda doesn't like cross-directory links,
1675         * so we fall back to a rename, which will mean that it
1676         * won't be able to check collisions, but that's not a
1677         * big deal.
1678         *
1679         * The same holds for FAT formatted media.
1680         *
1681         * When this succeeds, we just return 0. We have nothing
1682         * left to unlink.
1683         */
1684        if (ret && ret != EEXIST) {
1685                if (!rename(tmpfile, filename))
1686                        return 0;
1687                ret = errno;
1688        }
1689        unlink(tmpfile);
1690        if (ret) {
1691                if (ret != EEXIST) {
1692                        return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1693                }
1694                /* FIXME!!! Collision check here ? */
1695        }
1696
1697        return 0;
1698}
1699
1700static int write_buffer(int fd, const void *buf, size_t len)
1701{
1702        if (write_in_full(fd, buf, len) < 0)
1703                return error("file write error (%s)", strerror(errno));
1704        return 0;
1705}
1706
1707static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1708{
1709        int hdr_len;
1710        unsigned char c;
1711
1712        c = (type << 4) | (len & 15);
1713        len >>= 4;
1714        hdr_len = 1;
1715        while (len) {
1716                *hdr++ = c | 0x80;
1717                hdr_len++;
1718                c = (len & 0x7f);
1719                len >>= 7;
1720        }
1721        *hdr = c;
1722        return hdr_len;
1723}
1724
1725static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1726{
1727        int obj_type, hdrlen;
1728
1729        if (use_legacy_headers) {
1730                while (deflate(stream, 0) == Z_OK)
1731                        /* nothing */;
1732                return;
1733        }
1734        obj_type = type_from_string(type);
1735        hdrlen = write_binary_header(stream->next_out, obj_type, len);
1736        stream->total_out = hdrlen;
1737        stream->next_out += hdrlen;
1738        stream->avail_out -= hdrlen;
1739}
1740
1741int hash_sha1_file(void *buf, unsigned long len, const char *type,
1742                   unsigned char *sha1)
1743{
1744        char hdr[32];
1745        int hdrlen;
1746        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1747        return 0;
1748}
1749
1750int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1751{
1752        int size;
1753        unsigned char *compressed;
1754        z_stream stream;
1755        unsigned char sha1[20];
1756        char *filename;
1757        static char tmpfile[PATH_MAX];
1758        char hdr[32];
1759        int fd, hdrlen;
1760
1761        /* Normally if we have it in the pack then we do not bother writing
1762         * it out into .git/objects/??/?{38} file.
1763         */
1764        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1765        filename = sha1_file_name(sha1);
1766        if (returnsha1)
1767                hashcpy(returnsha1, sha1);
1768        if (has_sha1_file(sha1))
1769                return 0;
1770        fd = open(filename, O_RDONLY);
1771        if (fd >= 0) {
1772                /*
1773                 * FIXME!!! We might do collision checking here, but we'd
1774                 * need to uncompress the old file and check it. Later.
1775                 */
1776                close(fd);
1777                return 0;
1778        }
1779
1780        if (errno != ENOENT) {
1781                return error("sha1 file %s: %s\n", filename, strerror(errno));
1782        }
1783
1784        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1785
1786        fd = mkstemp(tmpfile);
1787        if (fd < 0) {
1788                if (errno == EPERM)
1789                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1790                else
1791                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1792        }
1793
1794        /* Set it up */
1795        memset(&stream, 0, sizeof(stream));
1796        deflateInit(&stream, zlib_compression_level);
1797        size = 8 + deflateBound(&stream, len+hdrlen);
1798        compressed = xmalloc(size);
1799
1800        /* Compress it */
1801        stream.next_out = compressed;
1802        stream.avail_out = size;
1803
1804        /* First header.. */
1805        stream.next_in = (unsigned char *)hdr;
1806        stream.avail_in = hdrlen;
1807        setup_object_header(&stream, type, len);
1808
1809        /* Then the data itself.. */
1810        stream.next_in = buf;
1811        stream.avail_in = len;
1812        while (deflate(&stream, Z_FINISH) == Z_OK)
1813                /* nothing */;
1814        deflateEnd(&stream);
1815        size = stream.total_out;
1816
1817        if (write_buffer(fd, compressed, size) < 0)
1818                die("unable to write sha1 file");
1819        fchmod(fd, 0444);
1820        close(fd);
1821        free(compressed);
1822
1823        return move_temp_to_file(tmpfile, filename);
1824}
1825
1826/*
1827 * We need to unpack and recompress the object for writing
1828 * it out to a different file.
1829 */
1830static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1831{
1832        size_t size;
1833        z_stream stream;
1834        unsigned char *unpacked;
1835        unsigned long len;
1836        enum object_type type;
1837        char hdr[32];
1838        int hdrlen;
1839        void *buf;
1840
1841        /* need to unpack and recompress it by itself */
1842        unpacked = read_packed_sha1(sha1, &type, &len);
1843        if (!unpacked)
1844                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1845
1846        hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
1847
1848        /* Set it up */
1849        memset(&stream, 0, sizeof(stream));
1850        deflateInit(&stream, zlib_compression_level);
1851        size = deflateBound(&stream, len + hdrlen);
1852        buf = xmalloc(size);
1853
1854        /* Compress it */
1855        stream.next_out = buf;
1856        stream.avail_out = size;
1857
1858        /* First header.. */
1859        stream.next_in = (void *)hdr;
1860        stream.avail_in = hdrlen;
1861        while (deflate(&stream, 0) == Z_OK)
1862                /* nothing */;
1863
1864        /* Then the data itself.. */
1865        stream.next_in = unpacked;
1866        stream.avail_in = len;
1867        while (deflate(&stream, Z_FINISH) == Z_OK)
1868                /* nothing */;
1869        deflateEnd(&stream);
1870        free(unpacked);
1871
1872        *objsize = stream.total_out;
1873        return buf;
1874}
1875
1876int write_sha1_to_fd(int fd, const unsigned char *sha1)
1877{
1878        int retval;
1879        unsigned long objsize;
1880        void *buf = map_sha1_file(sha1, &objsize);
1881
1882        if (buf) {
1883                retval = write_buffer(fd, buf, objsize);
1884                munmap(buf, objsize);
1885                return retval;
1886        }
1887
1888        buf = repack_object(sha1, &objsize);
1889        retval = write_buffer(fd, buf, objsize);
1890        free(buf);
1891        return retval;
1892}
1893
1894int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1895                       size_t bufsize, size_t *bufposn)
1896{
1897        char tmpfile[PATH_MAX];
1898        int local;
1899        z_stream stream;
1900        unsigned char real_sha1[20];
1901        unsigned char discard[4096];
1902        int ret;
1903        SHA_CTX c;
1904
1905        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1906
1907        local = mkstemp(tmpfile);
1908        if (local < 0) {
1909                if (errno == EPERM)
1910                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1911                else
1912                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1913        }
1914
1915        memset(&stream, 0, sizeof(stream));
1916
1917        inflateInit(&stream);
1918
1919        SHA1_Init(&c);
1920
1921        do {
1922                ssize_t size;
1923                if (*bufposn) {
1924                        stream.avail_in = *bufposn;
1925                        stream.next_in = (unsigned char *) buffer;
1926                        do {
1927                                stream.next_out = discard;
1928                                stream.avail_out = sizeof(discard);
1929                                ret = inflate(&stream, Z_SYNC_FLUSH);
1930                                SHA1_Update(&c, discard, sizeof(discard) -
1931                                            stream.avail_out);
1932                        } while (stream.avail_in && ret == Z_OK);
1933                        if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1934                                die("unable to write sha1 file");
1935                        memmove(buffer, buffer + *bufposn - stream.avail_in,
1936                                stream.avail_in);
1937                        *bufposn = stream.avail_in;
1938                        if (ret != Z_OK)
1939                                break;
1940                }
1941                size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
1942                if (size <= 0) {
1943                        close(local);
1944                        unlink(tmpfile);
1945                        if (!size)
1946                                return error("Connection closed?");
1947                        perror("Reading from connection");
1948                        return -1;
1949                }
1950                *bufposn += size;
1951        } while (1);
1952        inflateEnd(&stream);
1953
1954        close(local);
1955        SHA1_Final(real_sha1, &c);
1956        if (ret != Z_STREAM_END) {
1957                unlink(tmpfile);
1958                return error("File %s corrupted", sha1_to_hex(sha1));
1959        }
1960        if (hashcmp(sha1, real_sha1)) {
1961                unlink(tmpfile);
1962                return error("File %s has bad hash", sha1_to_hex(sha1));
1963        }
1964
1965        return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1966}
1967
1968int has_pack_index(const unsigned char *sha1)
1969{
1970        struct stat st;
1971        if (stat(sha1_pack_index_name(sha1), &st))
1972                return 0;
1973        return 1;
1974}
1975
1976int has_pack_file(const unsigned char *sha1)
1977{
1978        struct stat st;
1979        if (stat(sha1_pack_name(sha1), &st))
1980                return 0;
1981        return 1;
1982}
1983
1984int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
1985{
1986        struct pack_entry e;
1987        return find_pack_entry(sha1, &e, ignore_packed);
1988}
1989
1990int has_sha1_file(const unsigned char *sha1)
1991{
1992        struct stat st;
1993        struct pack_entry e;
1994
1995        if (find_pack_entry(sha1, &e, NULL))
1996                return 1;
1997        return find_sha1_file(sha1, &st) ? 1 : 0;
1998}
1999
2000/*
2001 * reads from fd as long as possible into a supplied buffer of size bytes.
2002 * If necessary the buffer's size is increased using realloc()
2003 *
2004 * returns 0 if anything went fine and -1 otherwise
2005 *
2006 * NOTE: both buf and size may change, but even when -1 is returned
2007 * you still have to free() it yourself.
2008 */
2009int read_pipe(int fd, char** return_buf, unsigned long* return_size)
2010{
2011        char* buf = *return_buf;
2012        unsigned long size = *return_size;
2013        int iret;
2014        unsigned long off = 0;
2015
2016        do {
2017                iret = xread(fd, buf + off, size - off);
2018                if (iret > 0) {
2019                        off += iret;
2020                        if (off == size) {
2021                                size *= 2;
2022                                buf = xrealloc(buf, size);
2023                        }
2024                }
2025        } while (iret > 0);
2026
2027        *return_buf = buf;
2028        *return_size = off;
2029
2030        if (iret < 0)
2031                return -1;
2032        return 0;
2033}
2034
2035int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
2036{
2037        unsigned long size = 4096;
2038        char *buf = xmalloc(size);
2039        int ret;
2040
2041        if (read_pipe(fd, &buf, &size)) {
2042                free(buf);
2043                return -1;
2044        }
2045
2046        if (!type)
2047                type = blob_type;
2048        if (write_object)
2049                ret = write_sha1_file(buf, size, type, sha1);
2050        else
2051                ret = hash_sha1_file(buf, size, type, sha1);
2052        free(buf);
2053        return ret;
2054}
2055
2056int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
2057             enum object_type type, const char *path)
2058{
2059        unsigned long size = st->st_size;
2060        void *buf;
2061        int ret, re_allocated = 0;
2062
2063        buf = "";
2064        if (size)
2065                buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2066        close(fd);
2067
2068        if (!type)
2069                type = OBJ_BLOB;
2070
2071        /*
2072         * Convert blobs to git internal format
2073         */
2074        if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
2075                unsigned long nsize = size;
2076                char *nbuf = buf;
2077                if (convert_to_git(path, &nbuf, &nsize)) {
2078                        if (size)
2079                                munmap(buf, size);
2080                        size = nsize;
2081                        buf = nbuf;
2082                        re_allocated = 1;
2083                }
2084        }
2085
2086        if (write_object)
2087                ret = write_sha1_file(buf, size, typename(type), sha1);
2088        else
2089                ret = hash_sha1_file(buf, size, typename(type), sha1);
2090        if (re_allocated) {
2091                free(buf);
2092                return ret;
2093        }
2094        if (size)
2095                munmap(buf, size);
2096        return ret;
2097}
2098
2099int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
2100{
2101        int fd;
2102        char *target;
2103
2104        switch (st->st_mode & S_IFMT) {
2105        case S_IFREG:
2106                fd = open(path, O_RDONLY);
2107                if (fd < 0)
2108                        return error("open(\"%s\"): %s", path,
2109                                     strerror(errno));
2110                if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
2111                        return error("%s: failed to insert into database",
2112                                     path);
2113                break;
2114        case S_IFLNK:
2115                target = xmalloc(st->st_size+1);
2116                if (readlink(path, target, st->st_size+1) != st->st_size) {
2117                        char *errstr = strerror(errno);
2118                        free(target);
2119                        return error("readlink(\"%s\"): %s", path,
2120                                     errstr);
2121                }
2122                if (!write_object)
2123                        hash_sha1_file(target, st->st_size, blob_type, sha1);
2124                else if (write_sha1_file(target, st->st_size, blob_type, sha1))
2125                        return error("%s: failed to insert into database",
2126                                     path);
2127                free(target);
2128                break;
2129        default:
2130                return error("%s: unsupported file type", path);
2131        }
2132        return 0;
2133}
2134
2135int read_pack_header(int fd, struct pack_header *header)
2136{
2137        char *c = (char*)header;
2138        ssize_t remaining = sizeof(struct pack_header);
2139        do {
2140                ssize_t r = xread(fd, c, remaining);
2141                if (r <= 0)
2142                        /* "eof before pack header was fully read" */
2143                        return PH_ERROR_EOF;
2144                remaining -= r;
2145                c += r;
2146        } while (remaining > 0);
2147        if (header->hdr_signature != htonl(PACK_SIGNATURE))
2148                /* "protocol error (pack signature mismatch detected)" */
2149                return PH_ERROR_PACK_SIGNATURE;
2150        if (!pack_version_ok(header->hdr_version))
2151                /* "protocol error (pack version unsupported)" */
2152                return PH_ERROR_PROTOCOL;
2153        return 0;
2154}