sha1_file.c

   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
  31 const unsigned char null_sha1[20];
  32
  33 static unsigned int sha1_file_open_flag = O_NOATIME;
  34
  35 signed 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
  70 int 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
  83 int 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
 116 char * 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
 134 static 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  */
 156 char *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
 174 char *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
 199 char *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
 224 struct alternate_object_database *alt_odb_list;
 225 static struct alternate_object_database **alt_odb_tail;
 226
 227 static 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  */
 244 static 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
 312 static 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
 349 static void read_info_alternates(const char * relative_base, int depth)
 350 {
 351         char *map;
 352         size_t mapsz;
 353         struct stat st;
 354         char path[PATH_MAX];
 355         int fd;
 356
 357         sprintf(path, "%s/info/alternates", relative_base);
 358         fd = open(path, O_RDONLY);
 359         if (fd < 0)
 360                 return;
 361         if (fstat(fd, &st) || (st.st_size == 0)) {
 362                 close(fd);
 363                 return;
 364         }
 365         mapsz = xsize_t(st.st_size);
 366         map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
 367         close(fd);
 368
 369         link_alt_odb_entries(map, map + mapsz, '\n', relative_base, depth);
 370
 371         munmap(map, mapsz);
 372 }
 373
 374 void prepare_alt_odb(void)
 375 {
 376         const char *alt;
 377
 378         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 379         if (!alt) alt = "";
 380
 381         if (alt_odb_tail)
 382                 return;
 383         alt_odb_tail = &alt_odb_list;
 384         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 385
 386         read_info_alternates(get_object_directory(), 0);
 387 }
 388
 389 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 390 {
 391         char *name = sha1_file_name(sha1);
 392         struct alternate_object_database *alt;
 393
 394         if (!stat(name, st))
 395                 return name;
 396         prepare_alt_odb();
 397         for (alt = alt_odb_list; alt; alt = alt->next) {
 398                 name = alt->name;
 399                 fill_sha1_path(name, sha1);
 400                 if (!stat(alt->base, st))
 401                         return alt->base;
 402         }
 403         return NULL;
 404 }
 405
 406 static unsigned int pack_used_ctr;
 407 static unsigned int pack_mmap_calls;
 408 static unsigned int peak_pack_open_windows;
 409 static unsigned int pack_open_windows;
 410 static size_t peak_pack_mapped;
 411 static size_t pack_mapped;
 412 struct packed_git *packed_git;
 413
 414 void pack_report()
 415 {
 416         fprintf(stderr,
 417                 "pack_report: getpagesize()            = %10" SZ_FMT "\n"
 418                 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 419                 "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
 420                 (size_t) getpagesize(),
 421                 packed_git_window_size,
 422                 packed_git_limit);
 423         fprintf(stderr,
 424                 "pack_report: pack_used_ctr            = %10u\n"
 425                 "pack_report: pack_mmap_calls          = %10u\n"
 426                 "pack_report: pack_open_windows        = %10u / %10u\n"
 427                 "pack_report: pack_mapped              = "
 428                         "%10" SZ_FMT " / %10" SZ_FMT "\n",
 429                 pack_used_ctr,
 430                 pack_mmap_calls,
 431                 pack_open_windows, peak_pack_open_windows,
 432                 pack_mapped, peak_pack_mapped);
 433 }
 434
 435 static int check_packed_git_idx(const char *path,
 436         unsigned long *idx_size_,
 437         void **idx_map_)
 438 {
 439         void *idx_map;
 440         uint32_t *index;
 441         size_t idx_size;
 442         uint32_t nr, i;
 443         int fd = open(path, O_RDONLY);
 444         struct stat st;
 445         if (fd < 0)
 446                 return -1;
 447         if (fstat(fd, &st)) {
 448                 close(fd);
 449                 return -1;
 450         }
 451         idx_size = xsize_t(st.st_size);
 452         if (idx_size < 4 * 256 + 20 + 20) {
 453                 close(fd);
 454                 return error("index file %s is too small", path);
 455         }
 456         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 457         close(fd);
 458
 459         index = idx_map;
 460         *idx_map_ = idx_map;
 461         *idx_size_ = idx_size;
 462
 463         /* a future index format would start with this, as older git
 464          * binaries would fail the non-monotonic index check below.
 465          * give a nicer warning to the user if we can.
 466          */
 467         if (index[0] == htonl(PACK_IDX_SIGNATURE)) {
 468                 munmap(idx_map, idx_size);
 469                 return error("index file %s is a newer version"
 470                         " and is not supported by this binary"
 471                         " (try upgrading GIT to a newer version)",
 472                         path);
 473         }
 474
 475         nr = 0;
 476         for (i = 0; i < 256; i++) {
 477                 uint32_t n = ntohl(index[i]);
 478                 if (n < nr) {
 479                         munmap(idx_map, idx_size);
 480                         return error("non-monotonic index %s", path);
 481                 }
 482                 nr = n;
 483         }
 484
 485         /*
 486          * Total size:
 487          *  - 256 index entries 4 bytes each
 488          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 489          *  - 20-byte SHA1 of the packfile
 490          *  - 20-byte SHA1 file checksum
 491          */
 492         if (idx_size != 4*256 + nr * 24 + 20 + 20) {
 493                 munmap(idx_map, idx_size);
 494                 return error("wrong index file size in %s", path);
 495         }
 496
 497         return 0;
 498 }
 499
 500 static void scan_windows(struct packed_git *p,
 501         struct packed_git **lru_p,
 502         struct pack_window **lru_w,
 503         struct pack_window **lru_l)
 504 {
 505         struct pack_window *w, *w_l;
 506
 507         for (w_l = NULL, w = p->windows; w; w = w->next) {
 508                 if (!w->inuse_cnt) {
 509                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 510                                 *lru_p = p;
 511                                 *lru_w = w;
 512                                 *lru_l = w_l;
 513                         }
 514                 }
 515                 w_l = w;
 516         }
 517 }
 518
 519 static int unuse_one_window(struct packed_git *current)
 520 {
 521         struct packed_git *p, *lru_p = NULL;
 522         struct pack_window *lru_w = NULL, *lru_l = NULL;
 523
 524         if (current)
 525                 scan_windows(current, &lru_p, &lru_w, &lru_l);
 526         for (p = packed_git; p; p = p->next)
 527                 scan_windows(p, &lru_p, &lru_w, &lru_l);
 528         if (lru_p) {
 529                 munmap(lru_w->base, lru_w->len);
 530                 pack_mapped -= lru_w->len;
 531                 if (lru_l)
 532                         lru_l->next = lru_w->next;
 533                 else {
 534                         lru_p->windows = lru_w->next;
 535                         if (!lru_p->windows && lru_p != current) {
 536                                 close(lru_p->pack_fd);
 537                                 lru_p->pack_fd = -1;
 538                         }
 539                 }
 540                 free(lru_w);
 541                 pack_open_windows--;
 542                 return 1;
 543         }
 544         return 0;
 545 }
 546
 547 void release_pack_memory(size_t need)
 548 {
 549         size_t cur = pack_mapped;
 550         while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 551                 ; /* nothing */
 552 }
 553
 554 void unuse_pack(struct pack_window **w_cursor)
 555 {
 556         struct pack_window *w = *w_cursor;
 557         if (w) {
 558                 w->inuse_cnt--;
 559                 *w_cursor = NULL;
 560         }
 561 }
 562
 563 /*
 564  * Do not call this directly as this leaks p->pack_fd on error return;
 565  * call open_packed_git() instead.
 566  */
 567 static int open_packed_git_1(struct packed_git *p)
 568 {
 569         struct stat st;
 570         struct pack_header hdr;
 571         unsigned char sha1[20];
 572         unsigned char *idx_sha1;
 573         long fd_flag;
 574
 575         p->pack_fd = open(p->pack_name, O_RDONLY);
 576         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 577                 return -1;
 578
 579         /* If we created the struct before we had the pack we lack size. */
 580         if (!p->pack_size) {
 581                 if (!S_ISREG(st.st_mode))
 582                         return error("packfile %s not a regular file", p->pack_name);
 583                 p->pack_size = st.st_size;
 584         } else if (p->pack_size != st.st_size)
 585                 return error("packfile %s size changed", p->pack_name);
 586
 587         /* We leave these file descriptors open with sliding mmap;
 588          * there is no point keeping them open across exec(), though.
 589          */
 590         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 591         if (fd_flag < 0)
 592                 return error("cannot determine file descriptor flags");
 593         fd_flag |= FD_CLOEXEC;
 594         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 595                 return error("cannot set FD_CLOEXEC");
 596
 597         /* Verify we recognize this pack file format. */
 598         if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 599                 return error("file %s is far too short to be a packfile", p->pack_name);
 600         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 601                 return error("file %s is not a GIT packfile", p->pack_name);
 602         if (!pack_version_ok(hdr.hdr_version))
 603                 return error("packfile %s is version %u and not supported"
 604                         " (try upgrading GIT to a newer version)",
 605                         p->pack_name, ntohl(hdr.hdr_version));
 606
 607         /* Verify the pack matches its index. */
 608         if (num_packed_objects(p) != ntohl(hdr.hdr_entries))
 609                 return error("packfile %s claims to have %u objects"
 610                         " while index size indicates %u objects",
 611                         p->pack_name, ntohl(hdr.hdr_entries),
 612                         num_packed_objects(p));
 613         if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
 614                 return error("end of packfile %s is unavailable", p->pack_name);
 615         if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
 616                 return error("packfile %s signature is unavailable", p->pack_name);
 617         idx_sha1 = ((unsigned char *)p->index_base) + p->index_size - 40;
 618         if (hashcmp(sha1, idx_sha1))
 619                 return error("packfile %s does not match index", p->pack_name);
 620         return 0;
 621 }
 622
 623 static int open_packed_git(struct packed_git *p)
 624 {
 625         if (!open_packed_git_1(p))
 626                 return 0;
 627         if (p->pack_fd != -1) {
 628                 close(p->pack_fd);
 629                 p->pack_fd = -1;
 630         }
 631         return -1;
 632 }
 633
 634 static int in_window(struct pack_window *win, off_t offset)
 635 {
 636         /* We must promise at least 20 bytes (one hash) after the
 637          * offset is available from this window, otherwise the offset
 638          * is not actually in this window and a different window (which
 639          * has that one hash excess) must be used.  This is to support
 640          * the object header and delta base parsing routines below.
 641          */
 642         off_t win_off = win->offset;
 643         return win_off <= offset
 644                 && (offset + 20) <= (win_off + win->len);
 645 }
 646
 647 unsigned char* use_pack(struct packed_git *p,
 648                 struct pack_window **w_cursor,
 649                 off_t offset,
 650                 unsigned int *left)
 651 {
 652         struct pack_window *win = *w_cursor;
 653
 654         if (p->pack_fd == -1 && open_packed_git(p))
 655                 die("packfile %s cannot be accessed", p->pack_name);
 656
 657         /* Since packfiles end in a hash of their content and its
 658          * pointless to ask for an offset into the middle of that
 659          * hash, and the in_window function above wouldn't match
 660          * don't allow an offset too close to the end of the file.
 661          */
 662         if (offset > (p->pack_size - 20))
 663                 die("offset beyond end of packfile (truncated pack?)");
 664
 665         if (!win || !in_window(win, offset)) {
 666                 if (win)
 667                         win->inuse_cnt--;
 668                 for (win = p->windows; win; win = win->next) {
 669                         if (in_window(win, offset))
 670                                 break;
 671                 }
 672                 if (!win) {
 673                         size_t window_align = packed_git_window_size / 2;
 674                         off_t len;
 675                         win = xcalloc(1, sizeof(*win));
 676                         win->offset = (offset / window_align) * window_align;
 677                         len = p->pack_size - win->offset;
 678                         if (len > packed_git_window_size)
 679                                 len = packed_git_window_size;
 680                         win->len = (size_t)len;
 681                         pack_mapped += win->len;
 682                         while (packed_git_limit < pack_mapped
 683                                 && unuse_one_window(p))
 684                                 ; /* nothing */
 685                         win->base = xmmap(NULL, win->len,
 686                                 PROT_READ, MAP_PRIVATE,
 687                                 p->pack_fd, win->offset);
 688                         if (win->base == MAP_FAILED)
 689                                 die("packfile %s cannot be mapped: %s",
 690                                         p->pack_name,
 691                                         strerror(errno));
 692                         pack_mmap_calls++;
 693                         pack_open_windows++;
 694                         if (pack_mapped > peak_pack_mapped)
 695                                 peak_pack_mapped = pack_mapped;
 696                         if (pack_open_windows > peak_pack_open_windows)
 697                                 peak_pack_open_windows = pack_open_windows;
 698                         win->next = p->windows;
 699                         p->windows = win;
 700                 }
 701         }
 702         if (win != *w_cursor) {
 703                 win->last_used = pack_used_ctr++;
 704                 win->inuse_cnt++;
 705                 *w_cursor = win;
 706         }
 707         offset -= win->offset;
 708         if (left)
 709                 *left = win->len - xsize_t(offset);
 710         return win->base + offset;
 711 }
 712
 713 struct packed_git *add_packed_git(char *path, int path_len, int local)
 714 {
 715         struct stat st;
 716         struct packed_git *p;
 717         unsigned long idx_size;
 718         void *idx_map;
 719         unsigned char sha1[20];
 720
 721         if (check_packed_git_idx(path, &idx_size, &idx_map))
 722                 return NULL;
 723
 724         /* do we have a corresponding .pack file? */
 725         strcpy(path + path_len - 4, ".pack");
 726         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 727                 munmap(idx_map, idx_size);
 728                 return NULL;
 729         }
 730         /* ok, it looks sane as far as we can check without
 731          * actually mapping the pack file.
 732          */
 733         p = xmalloc(sizeof(*p) + path_len + 2);
 734         strcpy(p->pack_name, path);
 735         p->index_size = idx_size;
 736         p->pack_size = st.st_size;
 737         p->index_base = idx_map;
 738         p->next = NULL;
 739         p->windows = NULL;
 740         p->pack_fd = -1;
 741         p->pack_local = local;
 742         p->mtime = st.st_mtime;
 743         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 744                 hashcpy(p->sha1, sha1);
 745         return p;
 746 }
 747
 748 struct packed_git *parse_pack_index(unsigned char *sha1)
 749 {
 750         char *path = sha1_pack_index_name(sha1);
 751         return parse_pack_index_file(sha1, path);
 752 }
 753
 754 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 755 {
 756         struct packed_git *p;
 757         unsigned long idx_size;
 758         void *idx_map;
 759         char *path;
 760
 761         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 762                 return NULL;
 763
 764         path = sha1_pack_name(sha1);
 765
 766         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 767         strcpy(p->pack_name, path);
 768         p->index_size = idx_size;
 769         p->pack_size = 0;
 770         p->index_base = idx_map;
 771         p->next = NULL;
 772         p->windows = NULL;
 773         p->pack_fd = -1;
 774         hashcpy(p->sha1, sha1);
 775         return p;
 776 }
 777
 778 void install_packed_git(struct packed_git *pack)
 779 {
 780         pack->next = packed_git;
 781         packed_git = pack;
 782 }
 783
 784 static void prepare_packed_git_one(char *objdir, int local)
 785 {
 786         char path[PATH_MAX];
 787         int len;
 788         DIR *dir;
 789         struct dirent *de;
 790
 791         sprintf(path, "%s/pack", objdir);
 792         len = strlen(path);
 793         dir = opendir(path);
 794         if (!dir) {
 795                 if (errno != ENOENT)
 796                         error("unable to open object pack directory: %s: %s",
 797                               path, strerror(errno));
 798                 return;
 799         }
 800         path[len++] = '/';
 801         while ((de = readdir(dir)) != NULL) {
 802                 int namelen = strlen(de->d_name);
 803                 struct packed_git *p;
 804
 805                 if (!has_extension(de->d_name, ".idx"))
 806                         continue;
 807
 808                 /* Don't reopen a pack we already have. */
 809                 strcpy(path + len, de->d_name);
 810                 for (p = packed_git; p; p = p->next) {
 811                         if (!memcmp(path, p->pack_name, len + namelen - 4))
 812                                 break;
 813                 }
 814                 if (p)
 815                         continue;
 816                 /* See if it really is a valid .idx file with corresponding
 817                  * .pack file that we can map.
 818                  */
 819                 p = add_packed_git(path, len + namelen, local);
 820                 if (!p)
 821                         continue;
 822                 install_packed_git(p);
 823         }
 824         closedir(dir);
 825 }
 826
 827 static int sort_pack(const void *a_, const void *b_)
 828 {
 829         struct packed_git *a = *((struct packed_git **)a_);
 830         struct packed_git *b = *((struct packed_git **)b_);
 831         int st;
 832
 833         /*
 834          * Local packs tend to contain objects specific to our
 835          * variant of the project than remote ones.  In addition,
 836          * remote ones could be on a network mounted filesystem.
 837          * Favor local ones for these reasons.
 838          */
 839         st = a->pack_local - b->pack_local;
 840         if (st)
 841                 return -st;
 842
 843         /*
 844          * Younger packs tend to contain more recent objects,
 845          * and more recent objects tend to get accessed more
 846          * often.
 847          */
 848         if (a->mtime < b->mtime)
 849                 return 1;
 850         else if (a->mtime == b->mtime)
 851                 return 0;
 852         return -1;
 853 }
 854
 855 static void rearrange_packed_git(void)
 856 {
 857         struct packed_git **ary, *p;
 858         int i, n;
 859
 860         for (n = 0, p = packed_git; p; p = p->next)
 861                 n++;
 862         if (n < 2)
 863                 return;
 864
 865         /* prepare an array of packed_git for easier sorting */
 866         ary = xcalloc(n, sizeof(struct packed_git *));
 867         for (n = 0, p = packed_git; p; p = p->next)
 868                 ary[n++] = p;
 869
 870         qsort(ary, n, sizeof(struct packed_git *), sort_pack);
 871
 872         /* link them back again */
 873         for (i = 0; i < n - 1; i++)
 874                 ary[i]->next = ary[i + 1];
 875         ary[n - 1]->next = NULL;
 876         packed_git = ary[0];
 877
 878         free(ary);
 879 }
 880
 881 static int prepare_packed_git_run_once = 0;
 882 void prepare_packed_git(void)
 883 {
 884         struct alternate_object_database *alt;
 885
 886         if (prepare_packed_git_run_once)
 887                 return;
 888         prepare_packed_git_one(get_object_directory(), 1);
 889         prepare_alt_odb();
 890         for (alt = alt_odb_list; alt; alt = alt->next) {
 891                 alt->name[-1] = 0;
 892                 prepare_packed_git_one(alt->base, 0);
 893                 alt->name[-1] = '/';
 894         }
 895         rearrange_packed_git();
 896         prepare_packed_git_run_once = 1;
 897 }
 898
 899 void reprepare_packed_git(void)
 900 {
 901         prepare_packed_git_run_once = 0;
 902         prepare_packed_git();
 903 }
 904
 905 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 906 {
 907         unsigned char real_sha1[20];
 908         hash_sha1_file(map, size, type, real_sha1);
 909         return hashcmp(sha1, real_sha1) ? -1 : 0;
 910 }
 911
 912 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 913 {
 914         struct stat st;
 915         void *map;
 916         int fd;
 917         char *filename = find_sha1_file(sha1, &st);
 918
 919         if (!filename) {
 920                 return NULL;
 921         }
 922
 923         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 924         if (fd < 0) {
 925                 /* See if it works without O_NOATIME */
 926                 switch (sha1_file_open_flag) {
 927                 default:
 928                         fd = open(filename, O_RDONLY);
 929                         if (fd >= 0)
 930                                 break;
 931                 /* Fallthrough */
 932                 case 0:
 933                         return NULL;
 934                 }
 935
 936                 /* If it failed once, it will probably fail again.
 937                  * Stop using O_NOATIME
 938                  */
 939                 sha1_file_open_flag = 0;
 940         }
 941         *size = xsize_t(st.st_size);
 942         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 943         close(fd);
 944         return map;
 945 }
 946
 947 int legacy_loose_object(unsigned char *map)
 948 {
 949         unsigned int word;
 950
 951         /*
 952          * Is it a zlib-compressed buffer? If so, the first byte
 953          * must be 0x78 (15-bit window size, deflated), and the
 954          * first 16-bit word is evenly divisible by 31
 955          */
 956         word = (map[0] << 8) + map[1];
 957         if (map[0] == 0x78 && !(word % 31))
 958                 return 1;
 959         else
 960                 return 0;
 961 }
 962
 963 unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
 964 {
 965         unsigned shift;
 966         unsigned char c;
 967         unsigned long size;
 968         unsigned long used = 0;
 969
 970         c = buf[used++];
 971         *type = (c >> 4) & 7;
 972         size = c & 15;
 973         shift = 4;
 974         while (c & 0x80) {
 975                 if (len <= used)
 976                         return 0;
 977                 if (sizeof(long) * 8 <= shift)
 978                         return 0;
 979                 c = buf[used++];
 980                 size += (c & 0x7f) << shift;
 981                 shift += 7;
 982         }
 983         *sizep = size;
 984         return used;
 985 }
 986
 987 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 988 {
 989         unsigned long size, used;
 990         static const char valid_loose_object_type[8] = {
 991                 0, /* OBJ_EXT */
 992                 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
 993                 0, /* "delta" and others are invalid in a loose object */
 994         };
 995         enum object_type type;
 996
 997         /* Get the data stream */
 998         memset(stream, 0, sizeof(*stream));
 999         stream->next_in = map;
1000         stream->avail_in = mapsize;
1001         stream->next_out = buffer;
1002         stream->avail_out = bufsiz;
1003
1004         if (legacy_loose_object(map)) {
1005                 inflateInit(stream);
1006                 return inflate(stream, 0);
1007         }
1008
1009         used = unpack_object_header_gently(map, mapsize, &type, &size);
1010         if (!used || !valid_loose_object_type[type])
1011                 return -1;
1012         map += used;
1013         mapsize -= used;
1014
1015         /* Set up the stream for the rest.. */
1016         stream->next_in = map;
1017         stream->avail_in = mapsize;
1018         inflateInit(stream);
1019
1020         /* And generate the fake traditional header */
1021         stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
1022                                          typename(type), size);
1023         return 0;
1024 }
1025
1026 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1027 {
1028         int bytes = strlen(buffer) + 1;
1029         unsigned char *buf = xmalloc(1+size);
1030         unsigned long n;
1031         int status = Z_OK;
1032
1033         n = stream->total_out - bytes;
1034         if (n > size)
1035                 n = size;
1036         memcpy(buf, (char *) buffer + bytes, n);
1037         bytes = n;
1038         if (bytes < size) {
1039                 stream->next_out = buf + bytes;
1040                 stream->avail_out = size - bytes;
1041                 while (status == Z_OK)
1042                         status = inflate(stream, Z_FINISH);
1043         }
1044         buf[size] = 0;
1045         if ((status == Z_OK || status == Z_STREAM_END) && !stream->avail_in) {
1046                 inflateEnd(stream);
1047                 return buf;
1048         }
1049
1050         if (status < 0)
1051                 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1052         else if (stream->avail_in)
1053                 error("garbage at end of loose object '%s'",
1054                       sha1_to_hex(sha1));
1055         free(buf);
1056         return NULL;
1057 }
1058
1059 /*
1060  * We used to just use "sscanf()", but that's actually way
1061  * too permissive for what we want to check. So do an anal
1062  * object header parse by hand.
1063  */
1064 static int parse_sha1_header(const char *hdr, unsigned long *sizep)
1065 {
1066         char type[10];
1067         int i;
1068         unsigned long size;
1069
1070         /*
1071          * The type can be at most ten bytes (including the
1072          * terminating '\0' that we add), and is followed by
1073          * a space.
1074          */
1075         i = 0;
1076         for (;;) {
1077                 char c = *hdr++;
1078                 if (c == ' ')
1079                         break;
1080                 type[i++] = c;
1081                 if (i >= sizeof(type))
1082                         return -1;
1083         }
1084         type[i] = 0;
1085
1086         /*
1087          * The length must follow immediately, and be in canonical
1088          * decimal format (ie "010" is not valid).
1089          */
1090         size = *hdr++ - '0';
1091         if (size > 9)
1092                 return -1;
1093         if (size) {
1094                 for (;;) {
1095                         unsigned long c = *hdr - '0';
1096                         if (c > 9)
1097                                 break;
1098                         hdr++;
1099                         size = size * 10 + c;
1100                 }
1101         }
1102         *sizep = size;
1103
1104         /*
1105          * The length must be followed by a zero byte
1106          */
1107         return *hdr ? -1 : type_from_string(type);
1108 }
1109
1110 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1111 {
1112         int ret;
1113         z_stream stream;
1114         char hdr[8192];
1115
1116         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1117         if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1118                 return NULL;
1119
1120         return unpack_sha1_rest(&stream, hdr, *size, sha1);
1121 }
1122
1123 static off_t get_delta_base(struct packed_git *p,
1124                                     struct pack_window **w_curs,
1125                                     off_t *curpos,
1126                                     enum object_type type,
1127                                     off_t delta_obj_offset)
1128 {
1129         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1130         off_t base_offset;
1131
1132         /* use_pack() assured us we have [base_info, base_info + 20)
1133          * as a range that we can look at without walking off the
1134          * end of the mapped window.  Its actually the hash size
1135          * that is assured.  An OFS_DELTA longer than the hash size
1136          * is stupid, as then a REF_DELTA would be smaller to store.
1137          */
1138         if (type == OBJ_OFS_DELTA) {
1139                 unsigned used = 0;
1140                 unsigned char c = base_info[used++];
1141                 base_offset = c & 127;
1142                 while (c & 128) {
1143                         base_offset += 1;
1144                         if (!base_offset || base_offset & ~(~0UL >> 7))
1145                                 die("offset value overflow for delta base object");
1146                         c = base_info[used++];
1147                         base_offset = (base_offset << 7) + (c & 127);
1148                 }
1149                 base_offset = delta_obj_offset - base_offset;
1150                 if (base_offset >= delta_obj_offset)
1151                         die("delta base offset out of bound");
1152                 *curpos += used;
1153         } else if (type == OBJ_REF_DELTA) {
1154                 /* The base entry _must_ be in the same pack */
1155                 base_offset = find_pack_entry_one(base_info, p);
1156                 if (!base_offset)
1157                         die("failed to find delta-pack base object %s",
1158                                 sha1_to_hex(base_info));
1159                 *curpos += 20;
1160         } else
1161                 die("I am totally screwed");
1162         return base_offset;
1163 }
1164
1165 /* forward declaration for a mutually recursive function */
1166 static int packed_object_info(struct packed_git *p, off_t offset,
1167                               unsigned long *sizep);
1168
1169 static int packed_delta_info(struct packed_git *p,
1170                              struct pack_window **w_curs,
1171                              off_t curpos,
1172                              enum object_type type,
1173                              off_t obj_offset,
1174                              unsigned long *sizep)
1175 {
1176         off_t base_offset;
1177
1178         base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1179         type = packed_object_info(p, base_offset, NULL);
1180
1181         /* We choose to only get the type of the base object and
1182          * ignore potentially corrupt pack file that expects the delta
1183          * based on a base with a wrong size.  This saves tons of
1184          * inflate() calls.
1185          */
1186         if (sizep) {
1187                 const unsigned char *data;
1188                 unsigned char delta_head[20], *in;
1189                 z_stream stream;
1190                 int st;
1191
1192                 memset(&stream, 0, sizeof(stream));
1193                 stream.next_out = delta_head;
1194                 stream.avail_out = sizeof(delta_head);
1195
1196                 inflateInit(&stream);
1197                 do {
1198                         in = use_pack(p, w_curs, curpos, &stream.avail_in);
1199                         stream.next_in = in;
1200                         st = inflate(&stream, Z_FINISH);
1201                         curpos += stream.next_in - in;
1202                 } while ((st == Z_OK || st == Z_BUF_ERROR)
1203                         && stream.total_out < sizeof(delta_head));
1204                 inflateEnd(&stream);
1205                 if ((st != Z_STREAM_END) &&
1206                     stream.total_out != sizeof(delta_head))
1207                         die("delta data unpack-initial failed");
1208
1209                 /* Examine the initial part of the delta to figure out
1210                  * the result size.
1211                  */
1212                 data = delta_head;
1213
1214                 /* ignore base size */
1215                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1216
1217                 /* Read the result size */
1218                 *sizep = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1219         }
1220
1221         return type;
1222 }
1223
1224 static int unpack_object_header(struct packed_git *p,
1225                                 struct pack_window **w_curs,
1226                                 off_t *curpos,
1227                                 unsigned long *sizep)
1228 {
1229         unsigned char *base;
1230         unsigned int left;
1231         unsigned long used;
1232         enum object_type type;
1233
1234         /* use_pack() assures us we have [base, base + 20) available
1235          * as a range that we can look at at.  (Its actually the hash
1236          * size that is assured.)  With our object header encoding
1237          * the maximum deflated object size is 2^137, which is just
1238          * insane, so we know won't exceed what we have been given.
1239          */
1240         base = use_pack(p, w_curs, *curpos, &left);
1241         used = unpack_object_header_gently(base, left, &type, sizep);
1242         if (!used)
1243                 die("object offset outside of pack file");
1244         *curpos += used;
1245
1246         return type;
1247 }
1248
1249 const char *packed_object_info_detail(struct packed_git *p,
1250                                       off_t obj_offset,
1251                                       unsigned long *size,
1252                                       unsigned long *store_size,
1253                                       unsigned int *delta_chain_length,
1254                                       unsigned char *base_sha1)
1255 {
1256         struct pack_window *w_curs = NULL;
1257         off_t curpos;
1258         unsigned long dummy;
1259         unsigned char *next_sha1;
1260         enum object_type type;
1261
1262         *delta_chain_length = 0;
1263         curpos = obj_offset;
1264         type = unpack_object_header(p, &w_curs, &curpos, size);
1265
1266         for (;;) {
1267                 switch (type) {
1268                 default:
1269                         die("pack %s contains unknown object type %d",
1270                             p->pack_name, type);
1271                 case OBJ_COMMIT:
1272                 case OBJ_TREE:
1273                 case OBJ_BLOB:
1274                 case OBJ_TAG:
1275                         *store_size = 0; /* notyet */
1276                         unuse_pack(&w_curs);
1277                         return typename(type);
1278                 case OBJ_OFS_DELTA:
1279                         obj_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1280                         if (*delta_chain_length == 0) {
1281                                 /* TODO: find base_sha1 as pointed by curpos */
1282                                 hashclr(base_sha1);
1283                         }
1284                         break;
1285                 case OBJ_REF_DELTA:
1286                         next_sha1 = use_pack(p, &w_curs, curpos, NULL);
1287                         if (*delta_chain_length == 0)
1288                                 hashcpy(base_sha1, next_sha1);
1289                         obj_offset = find_pack_entry_one(next_sha1, p);
1290                         break;
1291                 }
1292                 (*delta_chain_length)++;
1293                 curpos = obj_offset;
1294                 type = unpack_object_header(p, &w_curs, &curpos, &dummy);
1295         }
1296 }
1297
1298 static int packed_object_info(struct packed_git *p, off_t obj_offset,
1299                               unsigned long *sizep)
1300 {
1301         struct pack_window *w_curs = NULL;
1302         unsigned long size;
1303         off_t curpos = obj_offset;
1304         enum object_type type;
1305
1306         type = unpack_object_header(p, &w_curs, &curpos, &size);
1307
1308         switch (type) {
1309         case OBJ_OFS_DELTA:
1310         case OBJ_REF_DELTA:
1311                 type = packed_delta_info(p, &w_curs, curpos,
1312                                          type, obj_offset, sizep);
1313                 break;
1314         case OBJ_COMMIT:
1315         case OBJ_TREE:
1316         case OBJ_BLOB:
1317         case OBJ_TAG:
1318                 if (sizep)
1319                         *sizep = size;
1320                 break;
1321         default:
1322                 die("pack %s contains unknown object type %d",
1323                     p->pack_name, type);
1324         }
1325         unuse_pack(&w_curs);
1326         return type;
1327 }
1328
1329 static void *unpack_compressed_entry(struct packed_git *p,
1330                                     struct pack_window **w_curs,
1331                                     off_t curpos,
1332                                     unsigned long size)
1333 {
1334         int st;
1335         z_stream stream;
1336         unsigned char *buffer, *in;
1337
1338         buffer = xmalloc(size + 1);
1339         buffer[size] = 0;
1340         memset(&stream, 0, sizeof(stream));
1341         stream.next_out = buffer;
1342         stream.avail_out = size;
1343
1344         inflateInit(&stream);
1345         do {
1346                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1347                 stream.next_in = in;
1348                 st = inflate(&stream, Z_FINISH);
1349                 curpos += stream.next_in - in;
1350         } while (st == Z_OK || st == Z_BUF_ERROR);
1351         inflateEnd(&stream);
1352         if ((st != Z_STREAM_END) || stream.total_out != size) {
1353                 free(buffer);
1354                 return NULL;
1355         }
1356
1357         return buffer;
1358 }
1359
1360 static void *unpack_delta_entry(struct packed_git *p,
1361                                 struct pack_window **w_curs,
1362                                 off_t curpos,
1363                                 unsigned long delta_size,
1364                                 off_t obj_offset,
1365                                 enum object_type *type,
1366                                 unsigned long *sizep)
1367 {
1368         void *delta_data, *result, *base;
1369         unsigned long base_size;
1370         off_t base_offset;
1371
1372         base_offset = get_delta_base(p, w_curs, &curpos, *type, obj_offset);
1373         base = unpack_entry(p, base_offset, type, &base_size);
1374         if (!base)
1375                 die("failed to read delta base object"
1376                     " at %"PRIuMAX" from %s",
1377                     (uintmax_t)base_offset, p->pack_name);
1378
1379         delta_data = unpack_compressed_entry(p, w_curs, curpos, delta_size);
1380         result = patch_delta(base, base_size,
1381                              delta_data, delta_size,
1382                              sizep);
1383         if (!result)
1384                 die("failed to apply delta");
1385         free(delta_data);
1386         free(base);
1387         return result;
1388 }
1389
1390 void *unpack_entry(struct packed_git *p, off_t obj_offset,
1391                    enum object_type *type, unsigned long *sizep)
1392 {
1393         struct pack_window *w_curs = NULL;
1394         off_t curpos = obj_offset;
1395         void *data;
1396
1397         *type = unpack_object_header(p, &w_curs, &curpos, sizep);
1398         switch (*type) {
1399         case OBJ_OFS_DELTA:
1400         case OBJ_REF_DELTA:
1401                 data = unpack_delta_entry(p, &w_curs, curpos, *sizep,
1402                                           obj_offset, type, sizep);
1403                 break;
1404         case OBJ_COMMIT:
1405         case OBJ_TREE:
1406         case OBJ_BLOB:
1407         case OBJ_TAG:
1408                 data = unpack_compressed_entry(p, &w_curs, curpos, *sizep);
1409                 break;
1410         default:
1411                 die("unknown object type %i in %s", *type, p->pack_name);
1412         }
1413         unuse_pack(&w_curs);
1414         return data;
1415 }
1416
1417 uint32_t num_packed_objects(const struct packed_git *p)
1418 {
1419         /* See check_packed_git_idx() */
1420         return (uint32_t)((p->index_size - 20 - 20 - 4*256) / 24);
1421 }
1422
1423 int nth_packed_object_sha1(const struct packed_git *p, uint32_t n,
1424                            unsigned char* sha1)
1425 {
1426         void *index = p->index_base + 256;
1427         if (num_packed_objects(p) <= n)
1428                 return -1;
1429         hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
1430         return 0;
1431 }
1432
1433 off_t find_pack_entry_one(const unsigned char *sha1,
1434                                   struct packed_git *p)
1435 {
1436         uint32_t *level1_ofs = p->index_base;
1437         int hi = ntohl(level1_ofs[*sha1]);
1438         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1439         void *index = p->index_base + 256;
1440
1441         do {
1442                 int mi = (lo + hi) / 2;
1443                 int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
1444                 if (!cmp)
1445                         return ntohl(*((uint32_t *)((char *)index + (24 * mi))));
1446                 if (cmp > 0)
1447                         hi = mi;
1448                 else
1449                         lo = mi+1;
1450         } while (lo < hi);
1451         return 0;
1452 }
1453
1454 static int matches_pack_name(struct packed_git *p, const char *ig)
1455 {
1456         const char *last_c, *c;
1457
1458         if (!strcmp(p->pack_name, ig))
1459                 return 0;
1460
1461         for (c = p->pack_name, last_c = c; *c;)
1462                 if (*c == '/')
1463                         last_c = ++c;
1464                 else
1465                         ++c;
1466         if (!strcmp(last_c, ig))
1467                 return 0;
1468
1469         return 1;
1470 }
1471
1472 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
1473 {
1474         struct packed_git *p;
1475         off_t offset;
1476
1477         prepare_packed_git();
1478
1479         for (p = packed_git; p; p = p->next) {
1480                 if (ignore_packed) {
1481                         const char **ig;
1482                         for (ig = ignore_packed; *ig; ig++)
1483                                 if (!matches_pack_name(p, *ig))
1484                                         break;
1485                         if (*ig)
1486                                 continue;
1487                 }
1488                 offset = find_pack_entry_one(sha1, p);
1489                 if (offset) {
1490                         /*
1491                          * We are about to tell the caller where they can
1492                          * locate the requested object.  We better make
1493                          * sure the packfile is still here and can be
1494                          * accessed before supplying that answer, as
1495                          * it may have been deleted since the index
1496                          * was loaded!
1497                          */
1498                         if (p->pack_fd == -1 && open_packed_git(p)) {
1499                                 error("packfile %s cannot be accessed", p->pack_name);
1500                                 continue;
1501                         }
1502                         e->offset = offset;
1503                         e->p = p;
1504                         hashcpy(e->sha1, sha1);
1505                         return 1;
1506                 }
1507         }
1508         return 0;
1509 }
1510
1511 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1512                                   struct packed_git *packs)
1513 {
1514         struct packed_git *p;
1515
1516         for (p = packs; p; p = p->next) {
1517                 if (find_pack_entry_one(sha1, p))
1518                         return p;
1519         }
1520         return NULL;
1521
1522 }
1523
1524 static int sha1_loose_object_info(const unsigned char *sha1, unsigned long *sizep)
1525 {
1526         int status;
1527         unsigned long mapsize, size;
1528         void *map;
1529         z_stream stream;
1530         char hdr[32];
1531
1532         map = map_sha1_file(sha1, &mapsize);
1533         if (!map)
1534                 return error("unable to find %s", sha1_to_hex(sha1));
1535         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1536                 status = error("unable to unpack %s header",
1537                                sha1_to_hex(sha1));
1538         else if ((status = parse_sha1_header(hdr, &size)) < 0)
1539                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1540         else if (sizep)
1541                 *sizep = size;
1542         inflateEnd(&stream);
1543         munmap(map, mapsize);
1544         return status;
1545 }
1546
1547 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1548 {
1549         struct pack_entry e;
1550
1551         if (!find_pack_entry(sha1, &e, NULL)) {
1552                 reprepare_packed_git();
1553                 if (!find_pack_entry(sha1, &e, NULL))
1554                         return sha1_loose_object_info(sha1, sizep);
1555         }
1556         return packed_object_info(e.p, e.offset, sizep);
1557 }
1558
1559 static void *read_packed_sha1(const unsigned char *sha1,
1560                               enum object_type *type, unsigned long *size)
1561 {
1562         struct pack_entry e;
1563
1564         if (!find_pack_entry(sha1, &e, NULL))
1565                 return NULL;
1566         else
1567                 return unpack_entry(e.p, e.offset, type, size);
1568 }
1569
1570 /*
1571  * This is meant to hold a *small* number of objects that you would
1572  * want read_sha1_file() to be able to return, but yet you do not want
1573  * to write them into the object store (e.g. a browse-only
1574  * application).
1575  */
1576 static struct cached_object {
1577         unsigned char sha1[20];
1578         enum object_type type;
1579         void *buf;
1580         unsigned long size;
1581 } *cached_objects;
1582 static int cached_object_nr, cached_object_alloc;
1583
1584 static struct cached_object *find_cached_object(const unsigned char *sha1)
1585 {
1586         int i;
1587         struct cached_object *co = cached_objects;
1588
1589         for (i = 0; i < cached_object_nr; i++, co++) {
1590                 if (!hashcmp(co->sha1, sha1))
1591                         return co;
1592         }
1593         return NULL;
1594 }
1595
1596 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1597                       unsigned char *sha1)
1598 {
1599         struct cached_object *co;
1600
1601         hash_sha1_file(buf, len, typename(type), sha1);
1602         if (has_sha1_file(sha1) || find_cached_object(sha1))
1603                 return 0;
1604         if (cached_object_alloc <= cached_object_nr) {
1605                 cached_object_alloc = alloc_nr(cached_object_alloc);
1606                 cached_objects = xrealloc(cached_objects,
1607                                           sizeof(*cached_objects) *
1608                                           cached_object_alloc);
1609         }
1610         co = &cached_objects[cached_object_nr++];
1611         co->size = len;
1612         co->type = type;
1613         co->buf = xmalloc(len);
1614         memcpy(co->buf, buf, len);
1615         hashcpy(co->sha1, sha1);
1616         return 0;
1617 }
1618
1619 void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
1620                      unsigned long *size)
1621 {
1622         unsigned long mapsize;
1623         void *map, *buf;
1624         struct cached_object *co;
1625
1626         co = find_cached_object(sha1);
1627         if (co) {
1628                 buf = xmalloc(co->size + 1);
1629                 memcpy(buf, co->buf, co->size);
1630                 ((char*)buf)[co->size] = 0;
1631                 *type = co->type;
1632                 *size = co->size;
1633                 return buf;
1634         }
1635
1636         buf = read_packed_sha1(sha1, type, size);
1637         if (buf)
1638                 return buf;
1639         map = map_sha1_file(sha1, &mapsize);
1640         if (map) {
1641                 buf = unpack_sha1_file(map, mapsize, type, size, sha1);
1642                 munmap(map, mapsize);
1643                 return buf;
1644         }
1645         reprepare_packed_git();
1646         return read_packed_sha1(sha1, type, size);
1647 }
1648
1649 void *read_object_with_reference(const unsigned char *sha1,
1650                                  const char *required_type_name,
1651                                  unsigned long *size,
1652                                  unsigned char *actual_sha1_return)
1653 {
1654         enum object_type type, required_type;
1655         void *buffer;
1656         unsigned long isize;
1657         unsigned char actual_sha1[20];
1658
1659         required_type = type_from_string(required_type_name);
1660         hashcpy(actual_sha1, sha1);
1661         while (1) {
1662                 int ref_length = -1;
1663                 const char *ref_type = NULL;
1664
1665                 buffer = read_sha1_file(actual_sha1, &type, &isize);
1666                 if (!buffer)
1667                         return NULL;
1668                 if (type == required_type) {
1669                         *size = isize;
1670                         if (actual_sha1_return)
1671                                 hashcpy(actual_sha1_return, actual_sha1);
1672                         return buffer;
1673                 }
1674                 /* Handle references */
1675                 else if (type == OBJ_COMMIT)
1676                         ref_type = "tree ";
1677                 else if (type == OBJ_TAG)
1678                         ref_type = "object ";
1679                 else {
1680                         free(buffer);
1681                         return NULL;
1682                 }
1683                 ref_length = strlen(ref_type);
1684
1685                 if (memcmp(buffer, ref_type, ref_length) ||
1686                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1687                         free(buffer);
1688                         return NULL;
1689                 }
1690                 free(buffer);
1691                 /* Now we have the ID of the referred-to object in
1692                  * actual_sha1.  Check again. */
1693         }
1694 }
1695
1696 static void write_sha1_file_prepare(void *buf, unsigned long len,
1697                                     const char *type, unsigned char *sha1,
1698                                     char *hdr, int *hdrlen)
1699 {
1700         SHA_CTX c;
1701
1702         /* Generate the header */
1703         *hdrlen = sprintf(hdr, "%s %lu", type, len)+1;
1704
1705         /* Sha1.. */
1706         SHA1_Init(&c);
1707         SHA1_Update(&c, hdr, *hdrlen);
1708         SHA1_Update(&c, buf, len);
1709         SHA1_Final(sha1, &c);
1710 }
1711
1712 /*
1713  * Link the tempfile to the final place, possibly creating the
1714  * last directory level as you do so.
1715  *
1716  * Returns the errno on failure, 0 on success.
1717  */
1718 static int link_temp_to_file(const char *tmpfile, const char *filename)
1719 {
1720         int ret;
1721         char *dir;
1722
1723         if (!link(tmpfile, filename))
1724                 return 0;
1725
1726         /*
1727          * Try to mkdir the last path component if that failed.
1728          *
1729          * Re-try the "link()" regardless of whether the mkdir
1730          * succeeds, since a race might mean that somebody
1731          * else succeeded.
1732          */
1733         ret = errno;
1734         dir = strrchr(filename, '/');
1735         if (dir) {
1736                 *dir = 0;
1737                 if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
1738                         *dir = '/';
1739                         return -2;
1740                 }
1741                 *dir = '/';
1742                 if (!link(tmpfile, filename))
1743                         return 0;
1744                 ret = errno;
1745         }
1746         return ret;
1747 }
1748
1749 /*
1750  * Move the just written object into its final resting place
1751  */
1752 int move_temp_to_file(const char *tmpfile, const char *filename)
1753 {
1754         int ret = link_temp_to_file(tmpfile, filename);
1755
1756         /*
1757          * Coda hack - coda doesn't like cross-directory links,
1758          * so we fall back to a rename, which will mean that it
1759          * won't be able to check collisions, but that's not a
1760          * big deal.
1761          *
1762          * The same holds for FAT formatted media.
1763          *
1764          * When this succeeds, we just return 0. We have nothing
1765          * left to unlink.
1766          */
1767         if (ret && ret != EEXIST) {
1768                 if (!rename(tmpfile, filename))
1769                         return 0;
1770                 ret = errno;
1771         }
1772         unlink(tmpfile);
1773         if (ret) {
1774                 if (ret != EEXIST) {
1775                         return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1776                 }
1777                 /* FIXME!!! Collision check here ? */
1778         }
1779
1780         return 0;
1781 }
1782
1783 static int write_buffer(int fd, const void *buf, size_t len)
1784 {
1785         if (write_in_full(fd, buf, len) < 0)
1786                 return error("file write error (%s)", strerror(errno));
1787         return 0;
1788 }
1789
1790 static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1791 {
1792         int hdr_len;
1793         unsigned char c;
1794
1795         c = (type << 4) | (len & 15);
1796         len >>= 4;
1797         hdr_len = 1;
1798         while (len) {
1799                 *hdr++ = c | 0x80;
1800                 hdr_len++;
1801                 c = (len & 0x7f);
1802                 len >>= 7;
1803         }
1804         *hdr = c;
1805         return hdr_len;
1806 }
1807
1808 static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1809 {
1810         int obj_type, hdrlen;
1811
1812         if (use_legacy_headers) {
1813                 while (deflate(stream, 0) == Z_OK)
1814                         /* nothing */;
1815                 return;
1816         }
1817         obj_type = type_from_string(type);
1818         hdrlen = write_binary_header(stream->next_out, obj_type, len);
1819         stream->total_out = hdrlen;
1820         stream->next_out += hdrlen;
1821         stream->avail_out -= hdrlen;
1822 }
1823
1824 int hash_sha1_file(void *buf, unsigned long len, const char *type,
1825                    unsigned char *sha1)
1826 {
1827         char hdr[32];
1828         int hdrlen;
1829         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1830         return 0;
1831 }
1832
1833 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1834 {
1835         int size;
1836         unsigned char *compressed;
1837         z_stream stream;
1838         unsigned char sha1[20];
1839         char *filename;
1840         static char tmpfile[PATH_MAX];
1841         char hdr[32];
1842         int fd, hdrlen;
1843
1844         /* Normally if we have it in the pack then we do not bother writing
1845          * it out into .git/objects/??/?{38} file.
1846          */
1847         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1848         filename = sha1_file_name(sha1);
1849         if (returnsha1)
1850                 hashcpy(returnsha1, sha1);
1851         if (has_sha1_file(sha1))
1852                 return 0;
1853         fd = open(filename, O_RDONLY);
1854         if (fd >= 0) {
1855                 /*
1856                  * FIXME!!! We might do collision checking here, but we'd
1857                  * need to uncompress the old file and check it. Later.
1858                  */
1859                 close(fd);
1860                 return 0;
1861         }
1862
1863         if (errno != ENOENT) {
1864                 return error("sha1 file %s: %s\n", filename, strerror(errno));
1865         }
1866
1867         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1868
1869         fd = mkstemp(tmpfile);
1870         if (fd < 0) {
1871                 if (errno == EPERM)
1872                         return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1873                 else
1874                         return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1875         }
1876
1877         /* Set it up */
1878         memset(&stream, 0, sizeof(stream));
1879         deflateInit(&stream, zlib_compression_level);
1880         size = 8 + deflateBound(&stream, len+hdrlen);
1881         compressed = xmalloc(size);
1882
1883         /* Compress it */
1884         stream.next_out = compressed;
1885         stream.avail_out = size;
1886
1887         /* First header.. */
1888         stream.next_in = (unsigned char *)hdr;
1889         stream.avail_in = hdrlen;
1890         setup_object_header(&stream, type, len);
1891
1892         /* Then the data itself.. */
1893         stream.next_in = buf;
1894         stream.avail_in = len;
1895         while (deflate(&stream, Z_FINISH) == Z_OK)
1896                 /* nothing */;
1897         deflateEnd(&stream);
1898         size = stream.total_out;
1899
1900         if (write_buffer(fd, compressed, size) < 0)
1901                 die("unable to write sha1 file");
1902         fchmod(fd, 0444);
1903         close(fd);
1904         free(compressed);
1905
1906         return move_temp_to_file(tmpfile, filename);
1907 }
1908
1909 /*
1910  * We need to unpack and recompress the object for writing
1911  * it out to a different file.
1912  */
1913 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1914 {
1915         size_t size;
1916         z_stream stream;
1917         unsigned char *unpacked;
1918         unsigned long len;
1919         enum object_type type;
1920         char hdr[32];
1921         int hdrlen;
1922         void *buf;
1923
1924         /* need to unpack and recompress it by itself */
1925         unpacked = read_packed_sha1(sha1, &type, &len);
1926         if (!unpacked)
1927                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1928
1929         hdrlen = sprintf(hdr, "%s %lu", typename(type), len) + 1;
1930
1931         /* Set it up */
1932         memset(&stream, 0, sizeof(stream));
1933         deflateInit(&stream, zlib_compression_level);
1934         size = deflateBound(&stream, len + hdrlen);
1935         buf = xmalloc(size);
1936
1937         /* Compress it */
1938         stream.next_out = buf;
1939         stream.avail_out = size;
1940
1941         /* First header.. */
1942         stream.next_in = (void *)hdr;
1943         stream.avail_in = hdrlen;
1944         while (deflate(&stream, 0) == Z_OK)
1945                 /* nothing */;
1946
1947         /* Then the data itself.. */
1948         stream.next_in = unpacked;
1949         stream.avail_in = len;
1950         while (deflate(&stream, Z_FINISH) == Z_OK)
1951                 /* nothing */;
1952         deflateEnd(&stream);
1953         free(unpacked);
1954
1955         *objsize = stream.total_out;
1956         return buf;
1957 }
1958
1959 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1960 {
1961         int retval;
1962         unsigned long objsize;
1963         void *buf = map_sha1_file(sha1, &objsize);
1964
1965         if (buf) {
1966                 retval = write_buffer(fd, buf, objsize);
1967                 munmap(buf, objsize);
1968                 return retval;
1969         }
1970
1971         buf = repack_object(sha1, &objsize);
1972         retval = write_buffer(fd, buf, objsize);
1973         free(buf);
1974         return retval;
1975 }
1976
1977 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1978                        size_t bufsize, size_t *bufposn)
1979 {
1980         char tmpfile[PATH_MAX];
1981         int local;
1982         z_stream stream;
1983         unsigned char real_sha1[20];
1984         unsigned char discard[4096];
1985         int ret;
1986         SHA_CTX c;
1987
1988         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1989
1990         local = mkstemp(tmpfile);
1991         if (local < 0) {
1992                 if (errno == EPERM)
1993                         return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1994                 else
1995                         return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1996         }
1997
1998         memset(&stream, 0, sizeof(stream));
1999
2000         inflateInit(&stream);
2001
2002         SHA1_Init(&c);
2003
2004         do {
2005                 ssize_t size;
2006                 if (*bufposn) {
2007                         stream.avail_in = *bufposn;
2008                         stream.next_in = (unsigned char *) buffer;
2009                         do {
2010                                 stream.next_out = discard;
2011                                 stream.avail_out = sizeof(discard);
2012                                 ret = inflate(&stream, Z_SYNC_FLUSH);
2013                                 SHA1_Update(&c, discard, sizeof(discard) -
2014                                             stream.avail_out);
2015                         } while (stream.avail_in && ret == Z_OK);
2016                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
2017                                 die("unable to write sha1 file");
2018                         memmove(buffer, buffer + *bufposn - stream.avail_in,
2019                                 stream.avail_in);
2020                         *bufposn = stream.avail_in;
2021                         if (ret != Z_OK)
2022                                 break;
2023                 }
2024                 size = xread(fd, buffer + *bufposn, bufsize - *bufposn);
2025                 if (size <= 0) {
2026                         close(local);
2027                         unlink(tmpfile);
2028                         if (!size)
2029                                 return error("Connection closed?");
2030                         perror("Reading from connection");
2031                         return -1;
2032                 }
2033                 *bufposn += size;
2034         } while (1);
2035         inflateEnd(&stream);
2036
2037         close(local);
2038         SHA1_Final(real_sha1, &c);
2039         if (ret != Z_STREAM_END) {
2040                 unlink(tmpfile);
2041                 return error("File %s corrupted", sha1_to_hex(sha1));
2042         }
2043         if (hashcmp(sha1, real_sha1)) {
2044                 unlink(tmpfile);
2045                 return error("File %s has bad hash", sha1_to_hex(sha1));
2046         }
2047
2048         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
2049 }
2050
2051 int has_pack_index(const unsigned char *sha1)
2052 {
2053         struct stat st;
2054         if (stat(sha1_pack_index_name(sha1), &st))
2055                 return 0;
2056         return 1;
2057 }
2058
2059 int has_pack_file(const unsigned char *sha1)
2060 {
2061         struct stat st;
2062         if (stat(sha1_pack_name(sha1), &st))
2063                 return 0;
2064         return 1;
2065 }
2066
2067 int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
2068 {
2069         struct pack_entry e;
2070         return find_pack_entry(sha1, &e, ignore_packed);
2071 }
2072
2073 int has_sha1_file(const unsigned char *sha1)
2074 {
2075         struct stat st;
2076         struct pack_entry e;
2077
2078         if (find_pack_entry(sha1, &e, NULL))
2079                 return 1;
2080         return find_sha1_file(sha1, &st) ? 1 : 0;
2081 }
2082
2083 /*
2084  * reads from fd as long as possible into a supplied buffer of size bytes.
2085  * If necessary the buffer's size is increased using realloc()
2086  *
2087  * returns 0 if anything went fine and -1 otherwise
2088  *
2089  * NOTE: both buf and size may change, but even when -1 is returned
2090  * you still have to free() it yourself.
2091  */
2092 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
2093 {
2094         char* buf = *return_buf;
2095         unsigned long size = *return_size;
2096         int iret;
2097         unsigned long off = 0;
2098
2099         do {
2100                 iret = xread(fd, buf + off, size - off);
2101                 if (iret > 0) {
2102                         off += iret;
2103                         if (off == size) {
2104                                 size *= 2;
2105                                 buf = xrealloc(buf, size);
2106                         }
2107                 }
2108         } while (iret > 0);
2109
2110         *return_buf = buf;
2111         *return_size = off;
2112
2113         if (iret < 0)
2114                 return -1;
2115         return 0;
2116 }
2117
2118 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
2119 {
2120         unsigned long size = 4096;
2121         char *buf = xmalloc(size);
2122         int ret;
2123
2124         if (read_pipe(fd, &buf, &size)) {
2125                 free(buf);
2126                 return -1;
2127         }
2128
2129         if (!type)
2130                 type = blob_type;
2131         if (write_object)
2132                 ret = write_sha1_file(buf, size, type, sha1);
2133         else
2134                 ret = hash_sha1_file(buf, size, type, sha1);
2135         free(buf);
2136         return ret;
2137 }
2138
2139 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
2140              enum object_type type, const char *path)
2141 {
2142         size_t size = xsize_t(st->st_size);
2143         void *buf = NULL;
2144         int ret, re_allocated = 0;
2145
2146         if (size)
2147                 buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
2148         close(fd);
2149
2150         if (!type)
2151                 type = OBJ_BLOB;
2152
2153         /*
2154          * Convert blobs to git internal format
2155          */
2156         if ((type == OBJ_BLOB) && S_ISREG(st->st_mode)) {
2157                 unsigned long nsize = size;
2158                 char *nbuf = buf;
2159                 if (convert_to_git(path, &nbuf, &nsize)) {
2160                         if (size)
2161                                 munmap(buf, size);
2162                         size = nsize;
2163                         buf = nbuf;
2164                         re_allocated = 1;
2165                 }
2166         }
2167
2168         if (write_object)
2169                 ret = write_sha1_file(buf, size, typename(type), sha1);
2170         else
2171                 ret = hash_sha1_file(buf, size, typename(type), sha1);
2172         if (re_allocated) {
2173                 free(buf);
2174                 return ret;
2175         }
2176         if (size)
2177                 munmap(buf, size);
2178         return ret;
2179 }
2180
2181 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
2182 {
2183         int fd;
2184         char *target;
2185         size_t len;
2186
2187         switch (st->st_mode & S_IFMT) {
2188         case S_IFREG:
2189                 fd = open(path, O_RDONLY);
2190                 if (fd < 0)
2191                         return error("open(\"%s\"): %s", path,
2192                                      strerror(errno));
2193                 if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
2194                         return error("%s: failed to insert into database",
2195                                      path);
2196                 break;
2197         case S_IFLNK:
2198                 len = xsize_t(st->st_size);
2199                 target = xmalloc(len + 1);
2200                 if (readlink(path, target, len + 1) != st->st_size) {
2201                         char *errstr = strerror(errno);
2202                         free(target);
2203                         return error("readlink(\"%s\"): %s", path,
2204                                      errstr);
2205                 }
2206                 if (!write_object)
2207                         hash_sha1_file(target, len, blob_type, sha1);
2208                 else if (write_sha1_file(target, len, blob_type, sha1))
2209                         return error("%s: failed to insert into database",
2210                                      path);
2211                 free(target);
2212                 break;
2213         default:
2214                 return error("%s: unsupported file type", path);
2215         }
2216         return 0;
2217 }
2218
2219 int read_pack_header(int fd, struct pack_header *header)
2220 {
2221         char *c = (char*)header;
2222         ssize_t remaining = sizeof(struct pack_header);
2223         do {
2224                 ssize_t r = xread(fd, c, remaining);
2225                 if (r <= 0)
2226                         /* "eof before pack header was fully read" */
2227                         return PH_ERROR_EOF;
2228                 remaining -= r;
2229                 c += r;
2230         } while (remaining > 0);
2231         if (header->hdr_signature != htonl(PACK_SIGNATURE))
2232                 /* "protocol error (pack signature mismatch detected)" */
2233                 return PH_ERROR_PACK_SIGNATURE;
2234         if (!pack_version_ok(header->hdr_version))
2235                 /* "protocol error (pack version unsupported)" */
2236                 return PH_ERROR_PROTOCOL;
2237         return 0;
2238 }