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