sha1_file.con commit t9200: do not test -x bit if the filesystem does not support it. (3c23d66)
   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;
 410static size_t page_size;
 411struct packed_git *packed_git;
 412
 413void pack_report()
 414{
 415        fprintf(stderr,
 416                "pack_report: getpagesize()            = %10" SZ_FMT "\n"
 417                "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 418                "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
 419                page_size,
 420                packed_git_window_size,
 421                packed_git_limit);
 422        fprintf(stderr,
 423                "pack_report: pack_used_ctr            = %10u\n"
 424                "pack_report: pack_mmap_calls          = %10u\n"
 425                "pack_report: pack_open_windows        = %10u / %10u\n"
 426                "pack_report: pack_mapped              = "
 427                        "%10" SZ_FMT " / %10" SZ_FMT "\n",
 428                pack_used_ctr,
 429                pack_mmap_calls,
 430                pack_open_windows, peak_pack_open_windows,
 431                pack_mapped, peak_pack_mapped);
 432}
 433
 434static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 435                                void **idx_map_)
 436{
 437        void *idx_map;
 438        uint32_t *index;
 439        unsigned long idx_size;
 440        int nr, i;
 441        int fd = open(path, O_RDONLY);
 442        struct stat st;
 443        if (fd < 0)
 444                return -1;
 445        if (fstat(fd, &st)) {
 446                close(fd);
 447                return -1;
 448        }
 449        idx_size = st.st_size;
 450        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 451        close(fd);
 452
 453        index = idx_map;
 454        *idx_map_ = idx_map;
 455        *idx_size_ = idx_size;
 456
 457        /* check index map */
 458        if (idx_size < 4*256 + 20 + 20)
 459                return error("index file %s is too small", path);
 460
 461        /* a future index format would start with this, as older git
 462         * binaries would fail the non-monotonic index check below.
 463         * give a nicer warning to the user if we can.
 464         */
 465        if (index[0] == htonl(PACK_IDX_SIGNATURE))
 466                return error("index file %s is a newer version"
 467                        " and is not supported by this binary"
 468                        " (try upgrading GIT to a newer version)",
 469                        path);
 470
 471        nr = 0;
 472        for (i = 0; i < 256; i++) {
 473                unsigned int n = ntohl(index[i]);
 474                if (n < nr)
 475                        return error("non-monotonic index %s", path);
 476                nr = n;
 477        }
 478
 479        /*
 480         * Total size:
 481         *  - 256 index entries 4 bytes each
 482         *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 483         *  - 20-byte SHA1 of the packfile
 484         *  - 20-byte SHA1 file checksum
 485         */
 486        if (idx_size != 4*256 + nr * 24 + 20 + 20)
 487                return error("wrong index file size in %s", path);
 488
 489        return 0;
 490}
 491
 492static void scan_windows(struct packed_git *p,
 493        struct packed_git **lru_p,
 494        struct pack_window **lru_w,
 495        struct pack_window **lru_l)
 496{
 497        struct pack_window *w, *w_l;
 498
 499        for (w_l = NULL, w = p->windows; w; w = w->next) {
 500                if (!w->inuse_cnt) {
 501                        if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 502                                *lru_p = p;
 503                                *lru_w = w;
 504                                *lru_l = w_l;
 505                        }
 506                }
 507                w_l = w;
 508        }
 509}
 510
 511static int unuse_one_window(struct packed_git *current)
 512{
 513        struct packed_git *p, *lru_p = NULL;
 514        struct pack_window *lru_w = NULL, *lru_l = NULL;
 515
 516        if (current)
 517                scan_windows(current, &lru_p, &lru_w, &lru_l);
 518        for (p = packed_git; p; p = p->next)
 519                scan_windows(p, &lru_p, &lru_w, &lru_l);
 520        if (lru_p) {
 521                munmap(lru_w->base, lru_w->len);
 522                pack_mapped -= lru_w->len;
 523                if (lru_l)
 524                        lru_l->next = lru_w->next;
 525                else {
 526                        lru_p->windows = lru_w->next;
 527                        if (!lru_p->windows && lru_p != current) {
 528                                close(lru_p->pack_fd);
 529                                lru_p->pack_fd = -1;
 530                        }
 531                }
 532                free(lru_w);
 533                pack_open_windows--;
 534                return 1;
 535        }
 536        return 0;
 537}
 538
 539void release_pack_memory(size_t need)
 540{
 541        size_t cur = pack_mapped;
 542        while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 543                ; /* nothing */
 544}
 545
 546void unuse_pack(struct pack_window **w_cursor)
 547{
 548        struct pack_window *w = *w_cursor;
 549        if (w) {
 550                w->inuse_cnt--;
 551                *w_cursor = NULL;
 552        }
 553}
 554
 555static void open_packed_git(struct packed_git *p)
 556{
 557        struct stat st;
 558        struct pack_header hdr;
 559        unsigned char sha1[20];
 560        unsigned char *idx_sha1;
 561        long fd_flag;
 562
 563        p->pack_fd = open(p->pack_name, O_RDONLY);
 564        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 565                die("packfile %s cannot be opened", p->pack_name);
 566
 567        /* If we created the struct before we had the pack we lack size. */
 568        if (!p->pack_size) {
 569                if (!S_ISREG(st.st_mode))
 570                        die("packfile %s not a regular file", p->pack_name);
 571                p->pack_size = st.st_size;
 572        } else if (p->pack_size != st.st_size)
 573                die("packfile %s size changed", p->pack_name);
 574
 575        /* We leave these file descriptors open with sliding mmap;
 576         * there is no point keeping them open across exec(), though.
 577         */
 578        fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 579        if (fd_flag < 0)
 580                die("cannot determine file descriptor flags");
 581        fd_flag |= FD_CLOEXEC;
 582        if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 583                die("cannot set FD_CLOEXEC");
 584
 585        /* Verify we recognize this pack file format. */
 586        if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 587                die("file %s is far too short to be a packfile", p->pack_name);
 588        if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 589                die("file %s is not a GIT packfile", p->pack_name);
 590        if (!pack_version_ok(hdr.hdr_version))
 591                die("packfile %s is version %u and not supported"
 592                        " (try upgrading GIT to a newer version)",
 593                        p->pack_name, ntohl(hdr.hdr_version));
 594
 595        /* Verify the pack matches its index. */
 596        if (num_packed_objects(p) != ntohl(hdr.hdr_entries))
 597                die("packfile %s claims to have %u objects"
 598                        " while index size indicates %u objects",
 599                        p->pack_name, ntohl(hdr.hdr_entries),
 600                        num_packed_objects(p));
 601        if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
 602                die("end of packfile %s is unavailable", p->pack_name);
 603        if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
 604                die("packfile %s signature is unavailable", p->pack_name);
 605        idx_sha1 = ((unsigned char *)p->index_base) + p->index_size - 40;
 606        if (hashcmp(sha1, idx_sha1))
 607                die("packfile %s does not match index", p->pack_name);
 608}
 609
 610static int in_window(struct pack_window *win, unsigned long offset)
 611{
 612        /* We must promise at least 20 bytes (one hash) after the
 613         * offset is available from this window, otherwise the offset
 614         * is not actually in this window and a different window (which
 615         * has that one hash excess) must be used.  This is to support
 616         * the object header and delta base parsing routines below.
 617         */
 618        off_t win_off = win->offset;
 619        return win_off <= offset
 620                && (offset + 20) <= (win_off + win->len);
 621}
 622
 623unsigned char* use_pack(struct packed_git *p,
 624                struct pack_window **w_cursor,
 625                unsigned long offset,
 626                unsigned int *left)
 627{
 628        struct pack_window *win = *w_cursor;
 629
 630        if (p->pack_fd == -1)
 631                open_packed_git(p);
 632
 633        /* Since packfiles end in a hash of their content and its
 634         * pointless to ask for an offset into the middle of that
 635         * hash, and the in_window function above wouldn't match
 636         * don't allow an offset too close to the end of the file.
 637         */
 638        if (offset > (p->pack_size - 20))
 639                die("offset beyond end of packfile (truncated pack?)");
 640
 641        if (!win || !in_window(win, offset)) {
 642                if (win)
 643                        win->inuse_cnt--;
 644                for (win = p->windows; win; win = win->next) {
 645                        if (in_window(win, offset))
 646                                break;
 647                }
 648                if (!win) {
 649                        if (!page_size)
 650                                page_size = getpagesize();
 651                        win = xcalloc(1, sizeof(*win));
 652                        win->offset = (offset / page_size) * page_size;
 653                        win->len = p->pack_size - win->offset;
 654                        if (win->len > packed_git_window_size)
 655                                win->len = packed_git_window_size;
 656                        pack_mapped += win->len;
 657                        while (packed_git_limit < pack_mapped
 658                                && unuse_one_window(p))
 659                                ; /* nothing */
 660                        win->base = xmmap(NULL, win->len,
 661                                PROT_READ, MAP_PRIVATE,
 662                                p->pack_fd, win->offset);
 663                        if (win->base == MAP_FAILED)
 664                                die("packfile %s cannot be mapped: %s",
 665                                        p->pack_name,
 666                                        strerror(errno));
 667                        pack_mmap_calls++;
 668                        pack_open_windows++;
 669                        if (pack_mapped > peak_pack_mapped)
 670                                peak_pack_mapped = pack_mapped;
 671                        if (pack_open_windows > peak_pack_open_windows)
 672                                peak_pack_open_windows = pack_open_windows;
 673                        win->next = p->windows;
 674                        p->windows = win;
 675                }
 676        }
 677        if (win != *w_cursor) {
 678                win->last_used = pack_used_ctr++;
 679                win->inuse_cnt++;
 680                *w_cursor = win;
 681        }
 682        offset -= win->offset;
 683        if (left)
 684                *left = win->len - offset;
 685        return win->base + offset;
 686}
 687
 688struct packed_git *add_packed_git(char *path, int path_len, int local)
 689{
 690        struct stat st;
 691        struct packed_git *p;
 692        unsigned long idx_size;
 693        void *idx_map;
 694        unsigned char sha1[20];
 695
 696        if (check_packed_git_idx(path, &idx_size, &idx_map))
 697                return NULL;
 698
 699        /* do we have a corresponding .pack file? */
 700        strcpy(path + path_len - 4, ".pack");
 701        if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 702                munmap(idx_map, idx_size);
 703                return NULL;
 704        }
 705        /* ok, it looks sane as far as we can check without
 706         * actually mapping the pack file.
 707         */
 708        p = xmalloc(sizeof(*p) + path_len + 2);
 709        strcpy(p->pack_name, path);
 710        p->index_size = idx_size;
 711        p->pack_size = st.st_size;
 712        p->index_base = idx_map;
 713        p->next = NULL;
 714        p->windows = NULL;
 715        p->pack_fd = -1;
 716        p->pack_local = local;
 717        if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 718                hashcpy(p->sha1, sha1);
 719        return p;
 720}
 721
 722struct packed_git *parse_pack_index(unsigned char *sha1)
 723{
 724        char *path = sha1_pack_index_name(sha1);
 725        return parse_pack_index_file(sha1, path);
 726}
 727
 728struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 729{
 730        struct packed_git *p;
 731        unsigned long idx_size;
 732        void *idx_map;
 733        char *path;
 734
 735        if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 736                return NULL;
 737
 738        path = sha1_pack_name(sha1);
 739
 740        p = xmalloc(sizeof(*p) + strlen(path) + 2);
 741        strcpy(p->pack_name, path);
 742        p->index_size = idx_size;
 743        p->pack_size = 0;
 744        p->index_base = idx_map;
 745        p->next = NULL;
 746        p->windows = NULL;
 747        p->pack_fd = -1;
 748        hashcpy(p->sha1, sha1);
 749        return p;
 750}
 751
 752void install_packed_git(struct packed_git *pack)
 753{
 754        pack->next = packed_git;
 755        packed_git = pack;
 756}
 757
 758static void prepare_packed_git_one(char *objdir, int local)
 759{
 760        char path[PATH_MAX];
 761        int len;
 762        DIR *dir;
 763        struct dirent *de;
 764
 765        sprintf(path, "%s/pack", objdir);
 766        len = strlen(path);
 767        dir = opendir(path);
 768        if (!dir) {
 769                if (errno != ENOENT)
 770                        error("unable to open object pack directory: %s: %s",
 771                              path, strerror(errno));
 772                return;
 773        }
 774        path[len++] = '/';
 775        while ((de = readdir(dir)) != NULL) {
 776                int namelen = strlen(de->d_name);
 777                struct packed_git *p;
 778
 779                if (!has_extension(de->d_name, ".idx"))
 780                        continue;
 781
 782                /* we have .idx.  Is it a file we can map? */
 783                strcpy(path + len, de->d_name);
 784                for (p = packed_git; p; p = p->next) {
 785                        if (!memcmp(path, p->pack_name, len + namelen - 4))
 786                                break;
 787                }
 788                if (p)
 789                        continue;
 790                p = add_packed_git(path, len + namelen, local);
 791                if (!p)
 792                        continue;
 793                p->next = packed_git;
 794                packed_git = p;
 795        }
 796        closedir(dir);
 797}
 798
 799static int prepare_packed_git_run_once = 0;
 800void prepare_packed_git(void)
 801{
 802        struct alternate_object_database *alt;
 803
 804        if (prepare_packed_git_run_once)
 805                return;
 806        prepare_packed_git_one(get_object_directory(), 1);
 807        prepare_alt_odb();
 808        for (alt = alt_odb_list; alt; alt = alt->next) {
 809                alt->name[-1] = 0;
 810                prepare_packed_git_one(alt->base, 0);
 811                alt->name[-1] = '/';
 812        }
 813        prepare_packed_git_run_once = 1;
 814}
 815
 816void reprepare_packed_git(void)
 817{
 818        prepare_packed_git_run_once = 0;
 819        prepare_packed_git();
 820}
 821
 822int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 823{
 824        unsigned char real_sha1[20];
 825        hash_sha1_file(map, size, type, real_sha1);
 826        return hashcmp(sha1, real_sha1) ? -1 : 0;
 827}
 828
 829void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 830{
 831        struct stat st;
 832        void *map;
 833        int fd;
 834        char *filename = find_sha1_file(sha1, &st);
 835
 836        if (!filename) {
 837                return NULL;
 838        }
 839
 840        fd = open(filename, O_RDONLY | sha1_file_open_flag);
 841        if (fd < 0) {
 842                /* See if it works without O_NOATIME */
 843                switch (sha1_file_open_flag) {
 844                default:
 845                        fd = open(filename, O_RDONLY);
 846                        if (fd >= 0)
 847                                break;
 848                /* Fallthrough */
 849                case 0:
 850                        return NULL;
 851                }
 852
 853                /* If it failed once, it will probably fail again.
 854                 * Stop using O_NOATIME
 855                 */
 856                sha1_file_open_flag = 0;
 857        }
 858        map = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 859        close(fd);
 860        *size = st.st_size;
 861        return map;
 862}
 863
 864int legacy_loose_object(unsigned char *map)
 865{
 866        unsigned int word;
 867
 868        /*
 869         * Is it a zlib-compressed buffer? If so, the first byte
 870         * must be 0x78 (15-bit window size, deflated), and the
 871         * first 16-bit word is evenly divisible by 31
 872         */
 873        word = (map[0] << 8) + map[1];
 874        if (map[0] == 0x78 && !(word % 31))
 875                return 1;
 876        else
 877                return 0;
 878}
 879
 880unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
 881{
 882        unsigned shift;
 883        unsigned char c;
 884        unsigned long size;
 885        unsigned long used = 0;
 886
 887        c = buf[used++];
 888        *type = (c >> 4) & 7;
 889        size = c & 15;
 890        shift = 4;
 891        while (c & 0x80) {
 892                if (len <= used)
 893                        return 0;
 894                if (sizeof(long) * 8 <= shift)
 895                        return 0;
 896                c = buf[used++];
 897                size += (c & 0x7f) << shift;
 898                shift += 7;
 899        }
 900        *sizep = size;
 901        return used;
 902}
 903
 904static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 905{
 906        unsigned long size, used;
 907        static const char valid_loose_object_type[8] = {
 908                0, /* OBJ_EXT */
 909                1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
 910                0, /* "delta" and others are invalid in a loose object */
 911        };
 912        enum object_type type;
 913
 914        /* Get the data stream */
 915        memset(stream, 0, sizeof(*stream));
 916        stream->next_in = map;
 917        stream->avail_in = mapsize;
 918        stream->next_out = buffer;
 919        stream->avail_out = bufsiz;
 920
 921        if (legacy_loose_object(map)) {
 922                inflateInit(stream);
 923                return inflate(stream, 0);
 924        }
 925
 926        used = unpack_object_header_gently(map, mapsize, &type, &size);
 927        if (!used || !valid_loose_object_type[type])
 928                return -1;
 929        map += used;
 930        mapsize -= used;
 931
 932        /* Set up the stream for the rest.. */
 933        stream->next_in = map;
 934        stream->avail_in = mapsize;
 935        inflateInit(stream);
 936
 937        /* And generate the fake traditional header */
 938        stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
 939                                         type_names[type], size);
 940        return 0;
 941}
 942
 943static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 944{
 945        int bytes = strlen(buffer) + 1;
 946        unsigned char *buf = xmalloc(1+size);
 947        unsigned long n;
 948
 949        n = stream->total_out - bytes;
 950        if (n > size)
 951                n = size;
 952        memcpy(buf, (char *) buffer + bytes, n);
 953        bytes = n;
 954        if (bytes < size) {
 955                stream->next_out = buf + bytes;
 956                stream->avail_out = size - bytes;
 957                while (inflate(stream, Z_FINISH) == Z_OK)
 958                        /* nothing */;
 959        }
 960        buf[size] = 0;
 961        inflateEnd(stream);
 962        return buf;
 963}
 964
 965/*
 966 * We used to just use "sscanf()", but that's actually way
 967 * too permissive for what we want to check. So do an anal
 968 * object header parse by hand.
 969 */
 970static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 971{
 972        int i;
 973        unsigned long size;
 974
 975        /*
 976         * The type can be at most ten bytes (including the 
 977         * terminating '\0' that we add), and is followed by
 978         * a space. 
 979         */
 980        i = 10;
 981        for (;;) {
 982                char c = *hdr++;
 983                if (c == ' ')
 984                        break;
 985                if (!--i)
 986                        return -1;
 987                *type++ = c;
 988        }
 989        *type = 0;
 990
 991        /*
 992         * The length must follow immediately, and be in canonical
 993         * decimal format (ie "010" is not valid).
 994         */
 995        size = *hdr++ - '0';
 996        if (size > 9)
 997                return -1;
 998        if (size) {
 999                for (;;) {
1000                        unsigned long c = *hdr - '0';
1001                        if (c > 9)
1002                                break;
1003                        hdr++;
1004                        size = size * 10 + c;
1005                }
1006        }
1007        *sizep = size;
1008
1009        /*
1010         * The length must be followed by a zero byte
1011         */
1012        return *hdr ? -1 : 0;
1013}
1014
1015void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
1016{
1017        int ret;
1018        z_stream stream;
1019        char hdr[8192];
1020
1021        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1022        if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
1023                return NULL;
1024
1025        return unpack_sha1_rest(&stream, hdr, *size);
1026}
1027
1028static unsigned long get_delta_base(struct packed_git *p,
1029                                    struct pack_window **w_curs,
1030                                    unsigned long offset,
1031                                    enum object_type kind,
1032                                    unsigned long delta_obj_offset,
1033                                    unsigned long *base_obj_offset)
1034{
1035        unsigned char *base_info = use_pack(p, w_curs, offset, NULL);
1036        unsigned long base_offset;
1037
1038        /* use_pack() assured us we have [base_info, base_info + 20)
1039         * as a range that we can look at without walking off the
1040         * end of the mapped window.  Its actually the hash size
1041         * that is assured.  An OFS_DELTA longer than the hash size
1042         * is stupid, as then a REF_DELTA would be smaller to store.
1043         */
1044        if (kind == OBJ_OFS_DELTA) {
1045                unsigned used = 0;
1046                unsigned char c = base_info[used++];
1047                base_offset = c & 127;
1048                while (c & 128) {
1049                        base_offset += 1;
1050                        if (!base_offset || base_offset & ~(~0UL >> 7))
1051                                die("offset value overflow for delta base object");
1052                        c = base_info[used++];
1053                        base_offset = (base_offset << 7) + (c & 127);
1054                }
1055                base_offset = delta_obj_offset - base_offset;
1056                if (base_offset >= delta_obj_offset)
1057                        die("delta base offset out of bound");
1058                offset += used;
1059        } else if (kind == OBJ_REF_DELTA) {
1060                /* The base entry _must_ be in the same pack */
1061                base_offset = find_pack_entry_one(base_info, p);
1062                if (!base_offset)
1063                        die("failed to find delta-pack base object %s",
1064                                sha1_to_hex(base_info));
1065                offset += 20;
1066        } else
1067                die("I am totally screwed");
1068        *base_obj_offset = base_offset;
1069        return offset;
1070}
1071
1072/* forward declaration for a mutually recursive function */
1073static int packed_object_info(struct packed_git *p, unsigned long offset,
1074                              char *type, unsigned long *sizep);
1075
1076static int packed_delta_info(struct packed_git *p,
1077                             struct pack_window **w_curs,
1078                             unsigned long offset,
1079                             enum object_type kind,
1080                             unsigned long obj_offset,
1081                             char *type,
1082                             unsigned long *sizep)
1083{
1084        unsigned long base_offset;
1085
1086        offset = get_delta_base(p, w_curs, offset, kind,
1087                obj_offset, &base_offset);
1088
1089        /* We choose to only get the type of the base object and
1090         * ignore potentially corrupt pack file that expects the delta
1091         * based on a base with a wrong size.  This saves tons of
1092         * inflate() calls.
1093         */
1094        if (packed_object_info(p, base_offset, type, NULL))
1095                die("cannot get info for delta-pack base");
1096
1097        if (sizep) {
1098                const unsigned char *data;
1099                unsigned char delta_head[20], *in;
1100                unsigned long result_size;
1101                z_stream stream;
1102                int st;
1103
1104                memset(&stream, 0, sizeof(stream));
1105                stream.next_out = delta_head;
1106                stream.avail_out = sizeof(delta_head);
1107
1108                inflateInit(&stream);
1109                do {
1110                        in = use_pack(p, w_curs, offset, &stream.avail_in);
1111                        stream.next_in = in;
1112                        st = inflate(&stream, Z_FINISH);
1113                        offset += stream.next_in - in;
1114                } while ((st == Z_OK || st == Z_BUF_ERROR)
1115                        && stream.total_out < sizeof(delta_head));
1116                inflateEnd(&stream);
1117                if ((st != Z_STREAM_END) &&
1118                    stream.total_out != sizeof(delta_head))
1119                        die("delta data unpack-initial failed");
1120
1121                /* Examine the initial part of the delta to figure out
1122                 * the result size.
1123                 */
1124                data = delta_head;
1125
1126                /* ignore base size */
1127                get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1128
1129                /* Read the result size */
1130                result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1131                *sizep = result_size;
1132        }
1133        return 0;
1134}
1135
1136static unsigned long unpack_object_header(struct packed_git *p,
1137                struct pack_window **w_curs,
1138                unsigned long offset,
1139                enum object_type *type,
1140                unsigned long *sizep)
1141{
1142        unsigned char *base;
1143        unsigned int left;
1144        unsigned long used;
1145
1146        /* use_pack() assures us we have [base, base + 20) available
1147         * as a range that we can look at at.  (Its actually the hash
1148         * size that is assurred.)  With our object header encoding
1149         * the maximum deflated object size is 2^137, which is just
1150         * insane, so we know won't exceed what we have been given.
1151         */
1152        base = use_pack(p, w_curs, offset, &left);
1153        used = unpack_object_header_gently(base, left, type, sizep);
1154        if (!used)
1155                die("object offset outside of pack file");
1156
1157        return offset + used;
1158}
1159
1160void packed_object_info_detail(struct packed_git *p,
1161                               unsigned long offset,
1162                               char *type,
1163                               unsigned long *size,
1164                               unsigned long *store_size,
1165                               unsigned int *delta_chain_length,
1166                               unsigned char *base_sha1)
1167{
1168        struct pack_window *w_curs = NULL;
1169        unsigned long obj_offset, val;
1170        unsigned char *next_sha1;
1171        enum object_type kind;
1172
1173        *delta_chain_length = 0;
1174        obj_offset = offset;
1175        offset = unpack_object_header(p, &w_curs, offset, &kind, size);
1176
1177        for (;;) {
1178                switch (kind) {
1179                default:
1180                        die("pack %s contains unknown object type %d",
1181                            p->pack_name, kind);
1182                case OBJ_COMMIT:
1183                case OBJ_TREE:
1184                case OBJ_BLOB:
1185                case OBJ_TAG:
1186                        strcpy(type, type_names[kind]);
1187                        *store_size = 0; /* notyet */
1188                        unuse_pack(&w_curs);
1189                        return;
1190                case OBJ_OFS_DELTA:
1191                        get_delta_base(p, &w_curs, offset, kind,
1192                                obj_offset, &offset);
1193                        if (*delta_chain_length == 0) {
1194                                /* TODO: find base_sha1 as pointed by offset */
1195                        }
1196                        break;
1197                case OBJ_REF_DELTA:
1198                        next_sha1 = use_pack(p, &w_curs, offset, NULL);
1199                        if (*delta_chain_length == 0)
1200                                hashcpy(base_sha1, next_sha1);
1201                        offset = find_pack_entry_one(next_sha1, p);
1202                        break;
1203                }
1204                obj_offset = offset;
1205                offset = unpack_object_header(p, &w_curs, offset, &kind, &val);
1206                (*delta_chain_length)++;
1207        }
1208}
1209
1210static int packed_object_info(struct packed_git *p, unsigned long offset,
1211                              char *type, unsigned long *sizep)
1212{
1213        struct pack_window *w_curs = NULL;
1214        unsigned long size, obj_offset = offset;
1215        enum object_type kind;
1216        int r;
1217
1218        offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
1219
1220        switch (kind) {
1221        case OBJ_OFS_DELTA:
1222        case OBJ_REF_DELTA:
1223                r = packed_delta_info(p, &w_curs, offset, kind,
1224                        obj_offset, type, sizep);
1225                unuse_pack(&w_curs);
1226                return r;
1227        case OBJ_COMMIT:
1228        case OBJ_TREE:
1229        case OBJ_BLOB:
1230        case OBJ_TAG:
1231                strcpy(type, type_names[kind]);
1232                unuse_pack(&w_curs);
1233                break;
1234        default:
1235                die("pack %s contains unknown object type %d",
1236                    p->pack_name, kind);
1237        }
1238        if (sizep)
1239                *sizep = size;
1240        return 0;
1241}
1242
1243static void *unpack_compressed_entry(struct packed_git *p,
1244                                    struct pack_window **w_curs,
1245                                    unsigned long offset,
1246                                    unsigned long size)
1247{
1248        int st;
1249        z_stream stream;
1250        unsigned char *buffer, *in;
1251
1252        buffer = xmalloc(size + 1);
1253        buffer[size] = 0;
1254        memset(&stream, 0, sizeof(stream));
1255        stream.next_out = buffer;
1256        stream.avail_out = size;
1257
1258        inflateInit(&stream);
1259        do {
1260                in = use_pack(p, w_curs, offset, &stream.avail_in);
1261                stream.next_in = in;
1262                st = inflate(&stream, Z_FINISH);
1263                offset += stream.next_in - in;
1264        } while (st == Z_OK || st == Z_BUF_ERROR);
1265        inflateEnd(&stream);
1266        if ((st != Z_STREAM_END) || stream.total_out != size) {
1267                free(buffer);
1268                return NULL;
1269        }
1270
1271        return buffer;
1272}
1273
1274static void *unpack_delta_entry(struct packed_git *p,
1275                                struct pack_window **w_curs,
1276                                unsigned long offset,
1277                                unsigned long delta_size,
1278                                enum object_type kind,
1279                                unsigned long obj_offset,
1280                                char *type,
1281                                unsigned long *sizep)
1282{
1283        void *delta_data, *result, *base;
1284        unsigned long result_size, base_size, base_offset;
1285
1286        offset = get_delta_base(p, w_curs, offset, kind,
1287                obj_offset, &base_offset);
1288        base = unpack_entry(p, base_offset, type, &base_size);
1289        if (!base)
1290                die("failed to read delta base object at %lu from %s",
1291                    base_offset, p->pack_name);
1292
1293        delta_data = unpack_compressed_entry(p, w_curs, offset, delta_size);
1294        result = patch_delta(base, base_size,
1295                             delta_data, delta_size,
1296                             &result_size);
1297        if (!result)
1298                die("failed to apply delta");
1299        free(delta_data);
1300        free(base);
1301        *sizep = result_size;
1302        return result;
1303}
1304
1305void *unpack_entry(struct packed_git *p, unsigned long offset,
1306                          char *type, unsigned long *sizep)
1307{
1308        struct pack_window *w_curs = NULL;
1309        unsigned long size, obj_offset = offset;
1310        enum object_type kind;
1311        void *retval;
1312
1313        offset = unpack_object_header(p, &w_curs, offset, &kind, &size);
1314        switch (kind) {
1315        case OBJ_OFS_DELTA:
1316        case OBJ_REF_DELTA:
1317                retval = unpack_delta_entry(p, &w_curs, offset, size,
1318                        kind, obj_offset, type, sizep);
1319                break;
1320        case OBJ_COMMIT:
1321        case OBJ_TREE:
1322        case OBJ_BLOB:
1323        case OBJ_TAG:
1324                strcpy(type, type_names[kind]);
1325                *sizep = size;
1326                retval = unpack_compressed_entry(p, &w_curs, offset, size);
1327                break;
1328        default:
1329                die("unknown object type %i in %s", kind, p->pack_name);
1330        }
1331        unuse_pack(&w_curs);
1332        return retval;
1333}
1334
1335int num_packed_objects(const struct packed_git *p)
1336{
1337        /* See check_packed_git_idx() */
1338        return (p->index_size - 20 - 20 - 4*256) / 24;
1339}
1340
1341int nth_packed_object_sha1(const struct packed_git *p, int n,
1342                           unsigned char* sha1)
1343{
1344        void *index = p->index_base + 256;
1345        if (n < 0 || num_packed_objects(p) <= n)
1346                return -1;
1347        hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
1348        return 0;
1349}
1350
1351unsigned long find_pack_entry_one(const unsigned char *sha1,
1352                                  struct packed_git *p)
1353{
1354        uint32_t *level1_ofs = p->index_base;
1355        int hi = ntohl(level1_ofs[*sha1]);
1356        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1357        void *index = p->index_base + 256;
1358
1359        do {
1360                int mi = (lo + hi) / 2;
1361                int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
1362                if (!cmp)
1363                        return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
1364                if (cmp > 0)
1365                        hi = mi;
1366                else
1367                        lo = mi+1;
1368        } while (lo < hi);
1369        return 0;
1370}
1371
1372static int matches_pack_name(struct packed_git *p, const char *ig)
1373{
1374        const char *last_c, *c;
1375
1376        if (!strcmp(p->pack_name, ig))
1377                return 0;
1378
1379        for (c = p->pack_name, last_c = c; *c;)
1380                if (*c == '/')
1381                        last_c = ++c;
1382                else
1383                        ++c;
1384        if (!strcmp(last_c, ig))
1385                return 0;
1386
1387        return 1;
1388}
1389
1390static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
1391{
1392        struct packed_git *p;
1393        unsigned long offset;
1394
1395        prepare_packed_git();
1396
1397        for (p = packed_git; p; p = p->next) {
1398                if (ignore_packed) {
1399                        const char **ig;
1400                        for (ig = ignore_packed; *ig; ig++)
1401                                if (!matches_pack_name(p, *ig))
1402                                        break;
1403                        if (*ig)
1404                                continue;
1405                }
1406                offset = find_pack_entry_one(sha1, p);
1407                if (offset) {
1408                        e->offset = offset;
1409                        e->p = p;
1410                        hashcpy(e->sha1, sha1);
1411                        return 1;
1412                }
1413        }
1414        return 0;
1415}
1416
1417struct packed_git *find_sha1_pack(const unsigned char *sha1, 
1418                                  struct packed_git *packs)
1419{
1420        struct packed_git *p;
1421
1422        for (p = packs; p; p = p->next) {
1423                if (find_pack_entry_one(sha1, p))
1424                        return p;
1425        }
1426        return NULL;
1427        
1428}
1429
1430static int sha1_loose_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1431{
1432        int status;
1433        unsigned long mapsize, size;
1434        void *map;
1435        z_stream stream;
1436        char hdr[128];
1437
1438        map = map_sha1_file(sha1, &mapsize);
1439        if (!map)
1440                return error("unable to find %s", sha1_to_hex(sha1));
1441        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1442                status = error("unable to unpack %s header",
1443                               sha1_to_hex(sha1));
1444        if (parse_sha1_header(hdr, type, &size) < 0)
1445                status = error("unable to parse %s header", sha1_to_hex(sha1));
1446        else {
1447                status = 0;
1448                if (sizep)
1449                        *sizep = size;
1450        }
1451        inflateEnd(&stream);
1452        munmap(map, mapsize);
1453        return status;
1454}
1455
1456int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1457{
1458        struct pack_entry e;
1459
1460        if (!find_pack_entry(sha1, &e, NULL)) {
1461                reprepare_packed_git();
1462                if (!find_pack_entry(sha1, &e, NULL))
1463                        return sha1_loose_object_info(sha1, type, sizep);
1464        }
1465        return packed_object_info(e.p, e.offset, type, sizep);
1466}
1467
1468static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1469{
1470        struct pack_entry e;
1471
1472        if (!find_pack_entry(sha1, &e, NULL))
1473                return NULL;
1474        else
1475                return unpack_entry(e.p, e.offset, type, size);
1476}
1477
1478void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1479{
1480        unsigned long mapsize;
1481        void *map, *buf;
1482
1483        buf = read_packed_sha1(sha1, type, size);
1484        if (buf)
1485                return buf;
1486        map = map_sha1_file(sha1, &mapsize);
1487        if (map) {
1488                buf = unpack_sha1_file(map, mapsize, type, size);
1489                munmap(map, mapsize);
1490                return buf;
1491        }
1492        reprepare_packed_git();
1493        return read_packed_sha1(sha1, type, size);
1494}
1495
1496void *read_object_with_reference(const unsigned char *sha1,
1497                                 const char *required_type,
1498                                 unsigned long *size,
1499                                 unsigned char *actual_sha1_return)
1500{
1501        char type[20];
1502        void *buffer;
1503        unsigned long isize;
1504        unsigned char actual_sha1[20];
1505
1506        hashcpy(actual_sha1, sha1);
1507        while (1) {
1508                int ref_length = -1;
1509                const char *ref_type = NULL;
1510
1511                buffer = read_sha1_file(actual_sha1, type, &isize);
1512                if (!buffer)
1513                        return NULL;
1514                if (!strcmp(type, required_type)) {
1515                        *size = isize;
1516                        if (actual_sha1_return)
1517                                hashcpy(actual_sha1_return, actual_sha1);
1518                        return buffer;
1519                }
1520                /* Handle references */
1521                else if (!strcmp(type, commit_type))
1522                        ref_type = "tree ";
1523                else if (!strcmp(type, tag_type))
1524                        ref_type = "object ";
1525                else {
1526                        free(buffer);
1527                        return NULL;
1528                }
1529                ref_length = strlen(ref_type);
1530
1531                if (memcmp(buffer, ref_type, ref_length) ||
1532                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1533                        free(buffer);
1534                        return NULL;
1535                }
1536                free(buffer);
1537                /* Now we have the ID of the referred-to object in
1538                 * actual_sha1.  Check again. */
1539        }
1540}
1541
1542static void write_sha1_file_prepare(void *buf, unsigned long len,
1543                                    const char *type, unsigned char *sha1,
1544                                    unsigned char *hdr, int *hdrlen)
1545{
1546        SHA_CTX c;
1547
1548        /* Generate the header */
1549        *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1550
1551        /* Sha1.. */
1552        SHA1_Init(&c);
1553        SHA1_Update(&c, hdr, *hdrlen);
1554        SHA1_Update(&c, buf, len);
1555        SHA1_Final(sha1, &c);
1556}
1557
1558/*
1559 * Link the tempfile to the final place, possibly creating the
1560 * last directory level as you do so.
1561 *
1562 * Returns the errno on failure, 0 on success.
1563 */
1564static int link_temp_to_file(const char *tmpfile, const char *filename)
1565{
1566        int ret;
1567        char *dir;
1568
1569        if (!link(tmpfile, filename))
1570                return 0;
1571
1572        /*
1573         * Try to mkdir the last path component if that failed.
1574         *
1575         * Re-try the "link()" regardless of whether the mkdir
1576         * succeeds, since a race might mean that somebody
1577         * else succeeded.
1578         */
1579        ret = errno;
1580        dir = strrchr(filename, '/');
1581        if (dir) {
1582                *dir = 0;
1583                if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
1584                        *dir = '/';
1585                        return -2;
1586                }
1587                *dir = '/';
1588                if (!link(tmpfile, filename))
1589                        return 0;
1590                ret = errno;
1591        }
1592        return ret;
1593}
1594
1595/*
1596 * Move the just written object into its final resting place
1597 */
1598int move_temp_to_file(const char *tmpfile, const char *filename)
1599{
1600        int ret = link_temp_to_file(tmpfile, filename);
1601
1602        /*
1603         * Coda hack - coda doesn't like cross-directory links,
1604         * so we fall back to a rename, which will mean that it
1605         * won't be able to check collisions, but that's not a
1606         * big deal.
1607         *
1608         * The same holds for FAT formatted media.
1609         *
1610         * When this succeeds, we just return 0. We have nothing
1611         * left to unlink.
1612         */
1613        if (ret && ret != EEXIST) {
1614                if (!rename(tmpfile, filename))
1615                        return 0;
1616                ret = errno;
1617        }
1618        unlink(tmpfile);
1619        if (ret) {
1620                if (ret != EEXIST) {
1621                        return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1622                }
1623                /* FIXME!!! Collision check here ? */
1624        }
1625
1626        return 0;
1627}
1628
1629static int write_buffer(int fd, const void *buf, size_t len)
1630{
1631        if (write_in_full(fd, buf, len) < 0)
1632                return error("file write error (%s)", strerror(errno));
1633        return 0;
1634}
1635
1636static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1637{
1638        int hdr_len;
1639        unsigned char c;
1640
1641        c = (type << 4) | (len & 15);
1642        len >>= 4;
1643        hdr_len = 1;
1644        while (len) {
1645                *hdr++ = c | 0x80;
1646                hdr_len++;
1647                c = (len & 0x7f);
1648                len >>= 7;
1649        }
1650        *hdr = c;
1651        return hdr_len;
1652}
1653
1654static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1655{
1656        int obj_type, hdr;
1657
1658        if (use_legacy_headers) {
1659                while (deflate(stream, 0) == Z_OK)
1660                        /* nothing */;
1661                return;
1662        }
1663        if (!strcmp(type, blob_type))
1664                obj_type = OBJ_BLOB;
1665        else if (!strcmp(type, tree_type))
1666                obj_type = OBJ_TREE;
1667        else if (!strcmp(type, commit_type))
1668                obj_type = OBJ_COMMIT;
1669        else if (!strcmp(type, tag_type))
1670                obj_type = OBJ_TAG;
1671        else
1672                die("trying to generate bogus object of type '%s'", type);
1673        hdr = write_binary_header(stream->next_out, obj_type, len);
1674        stream->total_out = hdr;
1675        stream->next_out += hdr;
1676        stream->avail_out -= hdr;
1677}
1678
1679int hash_sha1_file(void *buf, unsigned long len, const char *type,
1680                   unsigned char *sha1)
1681{
1682        unsigned char hdr[50];
1683        int hdrlen;
1684        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1685        return 0;
1686}
1687
1688int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1689{
1690        int size;
1691        unsigned char *compressed;
1692        z_stream stream;
1693        unsigned char sha1[20];
1694        char *filename;
1695        static char tmpfile[PATH_MAX];
1696        unsigned char hdr[50];
1697        int fd, hdrlen;
1698
1699        /* Normally if we have it in the pack then we do not bother writing
1700         * it out into .git/objects/??/?{38} file.
1701         */
1702        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1703        filename = sha1_file_name(sha1);
1704        if (returnsha1)
1705                hashcpy(returnsha1, sha1);
1706        if (has_sha1_file(sha1))
1707                return 0;
1708        fd = open(filename, O_RDONLY);
1709        if (fd >= 0) {
1710                /*
1711                 * FIXME!!! We might do collision checking here, but we'd
1712                 * need to uncompress the old file and check it. Later.
1713                 */
1714                close(fd);
1715                return 0;
1716        }
1717
1718        if (errno != ENOENT) {
1719                return error("sha1 file %s: %s\n", filename, strerror(errno));
1720        }
1721
1722        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1723
1724        fd = mkstemp(tmpfile);
1725        if (fd < 0) {
1726                if (errno == EPERM)
1727                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1728                else
1729                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1730        }
1731
1732        /* Set it up */
1733        memset(&stream, 0, sizeof(stream));
1734        deflateInit(&stream, zlib_compression_level);
1735        size = 8 + deflateBound(&stream, len+hdrlen);
1736        compressed = xmalloc(size);
1737
1738        /* Compress it */
1739        stream.next_out = compressed;
1740        stream.avail_out = size;
1741
1742        /* First header.. */
1743        stream.next_in = hdr;
1744        stream.avail_in = hdrlen;
1745        setup_object_header(&stream, type, len);
1746
1747        /* Then the data itself.. */
1748        stream.next_in = buf;
1749        stream.avail_in = len;
1750        while (deflate(&stream, Z_FINISH) == Z_OK)
1751                /* nothing */;
1752        deflateEnd(&stream);
1753        size = stream.total_out;
1754
1755        if (write_buffer(fd, compressed, size) < 0)
1756                die("unable to write sha1 file");
1757        fchmod(fd, 0444);
1758        close(fd);
1759        free(compressed);
1760
1761        return move_temp_to_file(tmpfile, filename);
1762}
1763
1764/*
1765 * We need to unpack and recompress the object for writing
1766 * it out to a different file.
1767 */
1768static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1769{
1770        size_t size;
1771        z_stream stream;
1772        unsigned char *unpacked;
1773        unsigned long len;
1774        char type[20];
1775        char hdr[50];
1776        int hdrlen;
1777        void *buf;
1778
1779        /* need to unpack and recompress it by itself */
1780        unpacked = read_packed_sha1(sha1, type, &len);
1781        if (!unpacked)
1782                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1783
1784        hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1785
1786        /* Set it up */
1787        memset(&stream, 0, sizeof(stream));
1788        deflateInit(&stream, zlib_compression_level);
1789        size = deflateBound(&stream, len + hdrlen);
1790        buf = xmalloc(size);
1791
1792        /* Compress it */
1793        stream.next_out = buf;
1794        stream.avail_out = size;
1795
1796        /* First header.. */
1797        stream.next_in = (void *)hdr;
1798        stream.avail_in = hdrlen;
1799        while (deflate(&stream, 0) == Z_OK)
1800                /* nothing */;
1801
1802        /* Then the data itself.. */
1803        stream.next_in = unpacked;
1804        stream.avail_in = len;
1805        while (deflate(&stream, Z_FINISH) == Z_OK)
1806                /* nothing */;
1807        deflateEnd(&stream);
1808        free(unpacked);
1809
1810        *objsize = stream.total_out;
1811        return buf;
1812}
1813
1814int write_sha1_to_fd(int fd, const unsigned char *sha1)
1815{
1816        int retval;
1817        unsigned long objsize;
1818        void *buf = map_sha1_file(sha1, &objsize);
1819
1820        if (buf) {
1821                retval = write_buffer(fd, buf, objsize);
1822                munmap(buf, objsize);
1823                return retval;
1824        }
1825
1826        buf = repack_object(sha1, &objsize);
1827        retval = write_buffer(fd, buf, objsize);
1828        free(buf);
1829        return retval;
1830}
1831
1832int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1833                       size_t bufsize, size_t *bufposn)
1834{
1835        char tmpfile[PATH_MAX];
1836        int local;
1837        z_stream stream;
1838        unsigned char real_sha1[20];
1839        unsigned char discard[4096];
1840        int ret;
1841        SHA_CTX c;
1842
1843        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1844
1845        local = mkstemp(tmpfile);
1846        if (local < 0) {
1847                if (errno == EPERM)
1848                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1849                else
1850                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1851        }
1852
1853        memset(&stream, 0, sizeof(stream));
1854
1855        inflateInit(&stream);
1856
1857        SHA1_Init(&c);
1858
1859        do {
1860                ssize_t size;
1861                if (*bufposn) {
1862                        stream.avail_in = *bufposn;
1863                        stream.next_in = (unsigned char *) buffer;
1864                        do {
1865                                stream.next_out = discard;
1866                                stream.avail_out = sizeof(discard);
1867                                ret = inflate(&stream, Z_SYNC_FLUSH);
1868                                SHA1_Update(&c, discard, sizeof(discard) -
1869                                            stream.avail_out);
1870                        } while (stream.avail_in && ret == Z_OK);
1871                        if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1872                                die("unable to write sha1 file");
1873                        memmove(buffer, buffer + *bufposn - stream.avail_in,
1874                                stream.avail_in);
1875                        *bufposn = stream.avail_in;
1876                        if (ret != Z_OK)
1877                                break;
1878                }
1879                size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
1880                if (size <= 0) {
1881                        close(local);
1882                        unlink(tmpfile);
1883                        if (!size)
1884                                return error("Connection closed?");
1885                        perror("Reading from connection");
1886                        return -1;
1887                }
1888                *bufposn += size;
1889        } while (1);
1890        inflateEnd(&stream);
1891
1892        close(local);
1893        SHA1_Final(real_sha1, &c);
1894        if (ret != Z_STREAM_END) {
1895                unlink(tmpfile);
1896                return error("File %s corrupted", sha1_to_hex(sha1));
1897        }
1898        if (hashcmp(sha1, real_sha1)) {
1899                unlink(tmpfile);
1900                return error("File %s has bad hash", sha1_to_hex(sha1));
1901        }
1902
1903        return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1904}
1905
1906int has_pack_index(const unsigned char *sha1)
1907{
1908        struct stat st;
1909        if (stat(sha1_pack_index_name(sha1), &st))
1910                return 0;
1911        return 1;
1912}
1913
1914int has_pack_file(const unsigned char *sha1)
1915{
1916        struct stat st;
1917        if (stat(sha1_pack_name(sha1), &st))
1918                return 0;
1919        return 1;
1920}
1921
1922int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
1923{
1924        struct pack_entry e;
1925        return find_pack_entry(sha1, &e, ignore_packed);
1926}
1927
1928int has_sha1_file(const unsigned char *sha1)
1929{
1930        struct stat st;
1931        struct pack_entry e;
1932
1933        if (find_pack_entry(sha1, &e, NULL))
1934                return 1;
1935        return find_sha1_file(sha1, &st) ? 1 : 0;
1936}
1937
1938/*
1939 * reads from fd as long as possible into a supplied buffer of size bytes.
1940 * If necessary the buffer's size is increased using realloc()
1941 *
1942 * returns 0 if anything went fine and -1 otherwise
1943 *
1944 * NOTE: both buf and size may change, but even when -1 is returned
1945 * you still have to free() it yourself.
1946 */
1947int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1948{
1949        char* buf = *return_buf;
1950        unsigned long size = *return_size;
1951        int iret;
1952        unsigned long off = 0;
1953
1954        do {
1955                iret = xread(fd, buf + off, size - off);
1956                if (iret > 0) {
1957                        off += iret;
1958                        if (off == size) {
1959                                size *= 2;
1960                                buf = xrealloc(buf, size);
1961                        }
1962                }
1963        } while (iret > 0);
1964
1965        *return_buf = buf;
1966        *return_size = off;
1967
1968        if (iret < 0)
1969                return -1;
1970        return 0;
1971}
1972
1973int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1974{
1975        unsigned long size = 4096;
1976        char *buf = xmalloc(size);
1977        int ret;
1978
1979        if (read_pipe(fd, &buf, &size)) {
1980                free(buf);
1981                return -1;
1982        }
1983
1984        if (!type)
1985                type = blob_type;
1986        if (write_object)
1987                ret = write_sha1_file(buf, size, type, sha1);
1988        else
1989                ret = hash_sha1_file(buf, size, type, sha1);
1990        free(buf);
1991        return ret;
1992}
1993
1994int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1995{
1996        unsigned long size = st->st_size;
1997        void *buf;
1998        int ret;
1999
2000        buf = "";
2001        if (size)
2002                buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2003        close(fd);
2004
2005        if (!type)
2006                type = blob_type;
2007        if (write_object)
2008                ret = write_sha1_file(buf, size, type, sha1);
2009        else
2010                ret = hash_sha1_file(buf, size, type, sha1);
2011        if (size)
2012                munmap(buf, size);
2013        return ret;
2014}
2015
2016int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
2017{
2018        int fd;
2019        char *target;
2020
2021        switch (st->st_mode & S_IFMT) {
2022        case S_IFREG:
2023                fd = open(path, O_RDONLY);
2024                if (fd < 0)
2025                        return error("open(\"%s\"): %s", path,
2026                                     strerror(errno));
2027                if (index_fd(sha1, fd, st, write_object, NULL) < 0)
2028                        return error("%s: failed to insert into database",
2029                                     path);
2030                break;
2031        case S_IFLNK:
2032                target = xmalloc(st->st_size+1);
2033                if (readlink(path, target, st->st_size+1) != st->st_size) {
2034                        char *errstr = strerror(errno);
2035                        free(target);
2036                        return error("readlink(\"%s\"): %s", path,
2037                                     errstr);
2038                }
2039                if (!write_object)
2040                        hash_sha1_file(target, st->st_size, blob_type, sha1);
2041                else if (write_sha1_file(target, st->st_size, blob_type, sha1))
2042                        return error("%s: failed to insert into database",
2043                                     path);
2044                free(target);
2045                break;
2046        default:
2047                return error("%s: unsupported file type", path);
2048        }
2049        return 0;
2050}
2051
2052int read_pack_header(int fd, struct pack_header *header)
2053{
2054        char *c = (char*)header;
2055        ssize_t remaining = sizeof(struct pack_header);
2056        do {
2057                ssize_t r = xread(fd, c, remaining);
2058                if (r <= 0)
2059                        /* "eof before pack header was fully read" */
2060                        return PH_ERROR_EOF;
2061                remaining -= r;
2062                c += r;
2063        } while (remaining > 0);
2064        if (header->hdr_signature != htonl(PACK_SIGNATURE))
2065                /* "protocol error (pack signature mismatch detected)" */
2066                return PH_ERROR_PACK_SIGNATURE;
2067        if (!pack_version_ok(header->hdr_version))
2068                /* "protocol error (pack version unsupported)" */
2069                return PH_ERROR_PROTOCOL;
2070        return 0;
2071}