4183f595edfe6086f5097a430cb48202db00c5c1
   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
  25const unsigned char null_sha1[20];
  26
  27static unsigned int sha1_file_open_flag = O_NOATIME;
  28
  29signed char hexval_table[256] = {
  30         -1, -1, -1, -1, -1, -1, -1, -1,                /* 00-07 */
  31         -1, -1, -1, -1, -1, -1, -1, -1,                /* 08-0f */
  32         -1, -1, -1, -1, -1, -1, -1, -1,                /* 10-17 */
  33         -1, -1, -1, -1, -1, -1, -1, -1,                /* 18-1f */
  34         -1, -1, -1, -1, -1, -1, -1, -1,                /* 20-27 */
  35         -1, -1, -1, -1, -1, -1, -1, -1,                /* 28-2f */
  36          0,  1,  2,  3,  4,  5,  6,  7,                /* 30-37 */
  37          8,  9, -1, -1, -1, -1, -1, -1,                /* 38-3f */
  38         -1, 10, 11, 12, 13, 14, 15, -1,                /* 40-47 */
  39         -1, -1, -1, -1, -1, -1, -1, -1,                /* 48-4f */
  40         -1, -1, -1, -1, -1, -1, -1, -1,                /* 50-57 */
  41         -1, -1, -1, -1, -1, -1, -1, -1,                /* 58-5f */
  42         -1, 10, 11, 12, 13, 14, 15, -1,                /* 60-67 */
  43         -1, -1, -1, -1, -1, -1, -1, -1,                /* 68-67 */
  44         -1, -1, -1, -1, -1, -1, -1, -1,                /* 70-77 */
  45         -1, -1, -1, -1, -1, -1, -1, -1,                /* 78-7f */
  46         -1, -1, -1, -1, -1, -1, -1, -1,                /* 80-87 */
  47         -1, -1, -1, -1, -1, -1, -1, -1,                /* 88-8f */
  48         -1, -1, -1, -1, -1, -1, -1, -1,                /* 90-97 */
  49         -1, -1, -1, -1, -1, -1, -1, -1,                /* 98-9f */
  50         -1, -1, -1, -1, -1, -1, -1, -1,                /* a0-a7 */
  51         -1, -1, -1, -1, -1, -1, -1, -1,                /* a8-af */
  52         -1, -1, -1, -1, -1, -1, -1, -1,                /* b0-b7 */
  53         -1, -1, -1, -1, -1, -1, -1, -1,                /* b8-bf */
  54         -1, -1, -1, -1, -1, -1, -1, -1,                /* c0-c7 */
  55         -1, -1, -1, -1, -1, -1, -1, -1,                /* c8-cf */
  56         -1, -1, -1, -1, -1, -1, -1, -1,                /* d0-d7 */
  57         -1, -1, -1, -1, -1, -1, -1, -1,                /* d8-df */
  58         -1, -1, -1, -1, -1, -1, -1, -1,                /* e0-e7 */
  59         -1, -1, -1, -1, -1, -1, -1, -1,                /* e8-ef */
  60         -1, -1, -1, -1, -1, -1, -1, -1,                /* f0-f7 */
  61         -1, -1, -1, -1, -1, -1, -1, -1,                /* f8-ff */
  62};
  63
  64int get_sha1_hex(const char *hex, unsigned char *sha1)
  65{
  66        int i;
  67        for (i = 0; i < 20; i++) {
  68                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  69                if (val & ~0xff)
  70                        return -1;
  71                *sha1++ = val;
  72                hex += 2;
  73        }
  74        return 0;
  75}
  76
  77int safe_create_leading_directories(char *path)
  78{
  79        char *pos = path;
  80        struct stat st;
  81
  82        if (*pos == '/')
  83                pos++;
  84
  85        while (pos) {
  86                pos = strchr(pos, '/');
  87                if (!pos)
  88                        break;
  89                *pos = 0;
  90                if (!stat(path, &st)) {
  91                        /* path exists */
  92                        if (!S_ISDIR(st.st_mode)) {
  93                                *pos = '/';
  94                                return -3;
  95                        }
  96                }
  97                else if (mkdir(path, 0777)) {
  98                        *pos = '/';
  99                        return -1;
 100                }
 101                else if (adjust_shared_perm(path)) {
 102                        *pos = '/';
 103                        return -2;
 104                }
 105                *pos++ = '/';
 106        }
 107        return 0;
 108}
 109
 110char * sha1_to_hex(const unsigned char *sha1)
 111{
 112        static int bufno;
 113        static char hexbuffer[4][50];
 114        static const char hex[] = "0123456789abcdef";
 115        char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
 116        int i;
 117
 118        for (i = 0; i < 20; i++) {
 119                unsigned int val = *sha1++;
 120                *buf++ = hex[val >> 4];
 121                *buf++ = hex[val & 0xf];
 122        }
 123        *buf = '\0';
 124
 125        return buffer;
 126}
 127
 128static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 129{
 130        int i;
 131        for (i = 0; i < 20; i++) {
 132                static char hex[] = "0123456789abcdef";
 133                unsigned int val = sha1[i];
 134                char *pos = pathbuf + i*2 + (i > 0);
 135                *pos++ = hex[val >> 4];
 136                *pos = hex[val & 0xf];
 137        }
 138}
 139
 140/*
 141 * NOTE! This returns a statically allocated buffer, so you have to be
 142 * careful about using it. Do a "xstrdup()" if you need to save the
 143 * filename.
 144 *
 145 * Also note that this returns the location for creating.  Reading
 146 * SHA1 file can happen from any alternate directory listed in the
 147 * DB_ENVIRONMENT environment variable if it is not found in
 148 * the primary object database.
 149 */
 150char *sha1_file_name(const unsigned char *sha1)
 151{
 152        static char *name, *base;
 153
 154        if (!base) {
 155                const char *sha1_file_directory = get_object_directory();
 156                int len = strlen(sha1_file_directory);
 157                base = xmalloc(len + 60);
 158                memcpy(base, sha1_file_directory, len);
 159                memset(base+len, 0, 60);
 160                base[len] = '/';
 161                base[len+3] = '/';
 162                name = base + len + 1;
 163        }
 164        fill_sha1_path(name, sha1);
 165        return base;
 166}
 167
 168char *sha1_pack_name(const unsigned char *sha1)
 169{
 170        static const char hex[] = "0123456789abcdef";
 171        static char *name, *base, *buf;
 172        int i;
 173
 174        if (!base) {
 175                const char *sha1_file_directory = get_object_directory();
 176                int len = strlen(sha1_file_directory);
 177                base = xmalloc(len + 60);
 178                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 179                name = base + len + 11;
 180        }
 181
 182        buf = name;
 183
 184        for (i = 0; i < 20; i++) {
 185                unsigned int val = *sha1++;
 186                *buf++ = hex[val >> 4];
 187                *buf++ = hex[val & 0xf];
 188        }
 189        
 190        return base;
 191}
 192
 193char *sha1_pack_index_name(const unsigned char *sha1)
 194{
 195        static const char hex[] = "0123456789abcdef";
 196        static char *name, *base, *buf;
 197        int i;
 198
 199        if (!base) {
 200                const char *sha1_file_directory = get_object_directory();
 201                int len = strlen(sha1_file_directory);
 202                base = xmalloc(len + 60);
 203                sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 204                name = base + len + 11;
 205        }
 206
 207        buf = name;
 208
 209        for (i = 0; i < 20; i++) {
 210                unsigned int val = *sha1++;
 211                *buf++ = hex[val >> 4];
 212                *buf++ = hex[val & 0xf];
 213        }
 214        
 215        return base;
 216}
 217
 218struct alternate_object_database *alt_odb_list;
 219static struct alternate_object_database **alt_odb_tail;
 220
 221static void read_info_alternates(const char * alternates, int depth);
 222
 223/*
 224 * Prepare alternate object database registry.
 225 *
 226 * The variable alt_odb_list points at the list of struct
 227 * alternate_object_database.  The elements on this list come from
 228 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 229 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 230 * whose contents is similar to that environment variable but can be
 231 * LF separated.  Its base points at a statically allocated buffer that
 232 * contains "/the/directory/corresponding/to/.git/objects/...", while
 233 * its name points just after the slash at the end of ".git/objects/"
 234 * in the example above, and has enough space to hold 40-byte hex
 235 * SHA1, an extra slash for the first level indirection, and the
 236 * terminating NUL.
 237 */
 238static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 239{
 240        struct stat st;
 241        const char *objdir = get_object_directory();
 242        struct alternate_object_database *ent;
 243        struct alternate_object_database *alt;
 244        /* 43 = 40-byte + 2 '/' + terminating NUL */
 245        int pfxlen = len;
 246        int entlen = pfxlen + 43;
 247        int base_len = -1;
 248
 249        if (*entry != '/' && relative_base) {
 250                /* Relative alt-odb */
 251                if (base_len < 0)
 252                        base_len = strlen(relative_base) + 1;
 253                entlen += base_len;
 254                pfxlen += base_len;
 255        }
 256        ent = xmalloc(sizeof(*ent) + entlen);
 257
 258        if (*entry != '/' && relative_base) {
 259                memcpy(ent->base, relative_base, base_len - 1);
 260                ent->base[base_len - 1] = '/';
 261                memcpy(ent->base + base_len, entry, len);
 262        }
 263        else
 264                memcpy(ent->base, entry, pfxlen);
 265
 266        ent->name = ent->base + pfxlen + 1;
 267        ent->base[pfxlen + 3] = '/';
 268        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 269
 270        /* Detect cases where alternate disappeared */
 271        if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 272                error("object directory %s does not exist; "
 273                      "check .git/objects/info/alternates.",
 274                      ent->base);
 275                free(ent);
 276                return -1;
 277        }
 278
 279        /* Prevent the common mistake of listing the same
 280         * thing twice, or object directory itself.
 281         */
 282        for (alt = alt_odb_list; alt; alt = alt->next) {
 283                if (!memcmp(ent->base, alt->base, pfxlen)) {
 284                        free(ent);
 285                        return -1;
 286                }
 287        }
 288        if (!memcmp(ent->base, objdir, pfxlen)) {
 289                free(ent);
 290                return -1;
 291        }
 292
 293        /* add the alternate entry */
 294        *alt_odb_tail = ent;
 295        alt_odb_tail = &(ent->next);
 296        ent->next = NULL;
 297
 298        /* recursively add alternates */
 299        read_info_alternates(ent->base, depth + 1);
 300
 301        ent->base[pfxlen] = '/';
 302
 303        return 0;
 304}
 305
 306static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 307                                 const char *relative_base, int depth)
 308{
 309        const char *cp, *last;
 310
 311        if (depth > 5) {
 312                error("%s: ignoring alternate object stores, nesting too deep.",
 313                                relative_base);
 314                return;
 315        }
 316
 317        last = alt;
 318        while (last < ep) {
 319                cp = last;
 320                if (cp < ep && *cp == '#') {
 321                        while (cp < ep && *cp != sep)
 322                                cp++;
 323                        last = cp + 1;
 324                        continue;
 325                }
 326                while (cp < ep && *cp != sep)
 327                        cp++;
 328                if (last != cp) {
 329                        if ((*last != '/') && depth) {
 330                                error("%s: ignoring relative alternate object store %s",
 331                                                relative_base, last);
 332                        } else {
 333                                link_alt_odb_entry(last, cp - last,
 334                                                relative_base, depth);
 335                        }
 336                }
 337                while (cp < ep && *cp == sep)
 338                        cp++;
 339                last = cp;
 340        }
 341}
 342
 343static void read_info_alternates(const char * relative_base, int depth)
 344{
 345        char *map;
 346        struct stat st;
 347        char path[PATH_MAX];
 348        int fd;
 349
 350        sprintf(path, "%s/info/alternates", relative_base);
 351        fd = open(path, O_RDONLY);
 352        if (fd < 0)
 353                return;
 354        if (fstat(fd, &st) || (st.st_size == 0)) {
 355                close(fd);
 356                return;
 357        }
 358        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 359        close(fd);
 360        if (map == MAP_FAILED)
 361                return;
 362
 363        link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
 364
 365        munmap(map, st.st_size);
 366}
 367
 368void prepare_alt_odb(void)
 369{
 370        const char *alt;
 371
 372        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 373        if (!alt) alt = "";
 374
 375        if (alt_odb_tail)
 376                return;
 377        alt_odb_tail = &alt_odb_list;
 378        link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 379
 380        read_info_alternates(get_object_directory(), 0);
 381}
 382
 383static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 384{
 385        char *name = sha1_file_name(sha1);
 386        struct alternate_object_database *alt;
 387
 388        if (!stat(name, st))
 389                return name;
 390        prepare_alt_odb();
 391        for (alt = alt_odb_list; alt; alt = alt->next) {
 392                name = alt->name;
 393                fill_sha1_path(name, sha1);
 394                if (!stat(alt->base, st))
 395                        return alt->base;
 396        }
 397        return NULL;
 398}
 399
 400static int pack_used_ctr;
 401static unsigned long pack_mapped;
 402struct packed_git *packed_git;
 403
 404static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 405                                void **idx_map_)
 406{
 407        void *idx_map;
 408        unsigned int *index;
 409        unsigned long idx_size;
 410        int nr, i;
 411        int fd = open(path, O_RDONLY);
 412        struct stat st;
 413        if (fd < 0)
 414                return -1;
 415        if (fstat(fd, &st)) {
 416                close(fd);
 417                return -1;
 418        }
 419        idx_size = st.st_size;
 420        idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 421        close(fd);
 422        if (idx_map == MAP_FAILED)
 423                return -1;
 424
 425        index = idx_map;
 426        *idx_map_ = idx_map;
 427        *idx_size_ = idx_size;
 428
 429        /* check index map */
 430        if (idx_size < 4*256 + 20 + 20)
 431                return error("index file too small");
 432        nr = 0;
 433        for (i = 0; i < 256; i++) {
 434                unsigned int n = ntohl(index[i]);
 435                if (n < nr)
 436                        return error("non-monotonic index");
 437                nr = n;
 438        }
 439
 440        /*
 441         * Total size:
 442         *  - 256 index entries 4 bytes each
 443         *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 444         *  - 20-byte SHA1 of the packfile
 445         *  - 20-byte SHA1 file checksum
 446         */
 447        if (idx_size != 4*256 + nr * 24 + 20 + 20)
 448                return error("wrong index file size");
 449
 450        return 0;
 451}
 452
 453static int unuse_one_packed_git(void)
 454{
 455        struct packed_git *p, *lru = NULL;
 456
 457        for (p = packed_git; p; p = p->next) {
 458                if (p->pack_use_cnt || !p->pack_base)
 459                        continue;
 460                if (!lru || p->pack_last_used < lru->pack_last_used)
 461                        lru = p;
 462        }
 463        if (!lru)
 464                return 0;
 465        munmap(lru->pack_base, lru->pack_size);
 466        lru->pack_base = NULL;
 467        return 1;
 468}
 469
 470void unuse_packed_git(struct packed_git *p)
 471{
 472        p->pack_use_cnt--;
 473}
 474
 475int use_packed_git(struct packed_git *p)
 476{
 477        if (!p->pack_size) {
 478                struct stat st;
 479                /* We created the struct before we had the pack */
 480                stat(p->pack_name, &st);
 481                if (!S_ISREG(st.st_mode))
 482                        die("packfile %s not a regular file", p->pack_name);
 483                p->pack_size = st.st_size;
 484        }
 485        if (!p->pack_base) {
 486                int fd;
 487                struct stat st;
 488                void *map;
 489                struct pack_header *hdr;
 490
 491                pack_mapped += p->pack_size;
 492                while (packed_git_limit < pack_mapped && unuse_one_packed_git())
 493                        ; /* nothing */
 494                fd = open(p->pack_name, O_RDONLY);
 495                if (fd < 0)
 496                        die("packfile %s cannot be opened", p->pack_name);
 497                if (fstat(fd, &st)) {
 498                        close(fd);
 499                        die("packfile %s cannot be opened", p->pack_name);
 500                }
 501                if (st.st_size != p->pack_size)
 502                        die("packfile %s size mismatch.", p->pack_name);
 503                map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 504                close(fd);
 505                if (map == MAP_FAILED)
 506                        die("packfile %s cannot be mapped.", p->pack_name);
 507                p->pack_base = map;
 508
 509                /* Check if we understand this pack file.  If we don't we're
 510                 * likely too old to handle it.
 511                 */
 512                hdr = map;
 513                if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 514                        die("packfile %s isn't actually a pack.", p->pack_name);
 515                if (!pack_version_ok(hdr->hdr_version))
 516                        die("packfile %s is version %i and not supported"
 517                                " (try upgrading GIT to a newer version)",
 518                                p->pack_name, ntohl(hdr->hdr_version));
 519
 520                /* Check if the pack file matches with the index file.
 521                 * this is cheap.
 522                 */
 523                if (hashcmp((unsigned char *)(p->index_base) +
 524                            p->index_size - 40,
 525                            (unsigned char *)p->pack_base +
 526                            p->pack_size - 20)) {
 527                        die("packfile %s does not match index.", p->pack_name);
 528                }
 529        }
 530        p->pack_last_used = pack_used_ctr++;
 531        p->pack_use_cnt++;
 532        return 0;
 533}
 534
 535struct packed_git *add_packed_git(char *path, int path_len, int local)
 536{
 537        struct stat st;
 538        struct packed_git *p;
 539        unsigned long idx_size;
 540        void *idx_map;
 541        unsigned char sha1[20];
 542
 543        if (check_packed_git_idx(path, &idx_size, &idx_map))
 544                return NULL;
 545
 546        /* do we have a corresponding .pack file? */
 547        strcpy(path + path_len - 4, ".pack");
 548        if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 549                munmap(idx_map, idx_size);
 550                return NULL;
 551        }
 552        /* ok, it looks sane as far as we can check without
 553         * actually mapping the pack file.
 554         */
 555        p = xmalloc(sizeof(*p) + path_len + 2);
 556        strcpy(p->pack_name, path);
 557        p->index_size = idx_size;
 558        p->pack_size = st.st_size;
 559        p->index_base = idx_map;
 560        p->next = NULL;
 561        p->pack_base = NULL;
 562        p->pack_last_used = 0;
 563        p->pack_use_cnt = 0;
 564        p->pack_local = local;
 565        if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 566                hashcpy(p->sha1, sha1);
 567        return p;
 568}
 569
 570struct packed_git *parse_pack_index(unsigned char *sha1)
 571{
 572        char *path = sha1_pack_index_name(sha1);
 573        return parse_pack_index_file(sha1, path);
 574}
 575
 576struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 577{
 578        struct packed_git *p;
 579        unsigned long idx_size;
 580        void *idx_map;
 581        char *path;
 582
 583        if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 584                return NULL;
 585
 586        path = sha1_pack_name(sha1);
 587
 588        p = xmalloc(sizeof(*p) + strlen(path) + 2);
 589        strcpy(p->pack_name, path);
 590        p->index_size = idx_size;
 591        p->pack_size = 0;
 592        p->index_base = idx_map;
 593        p->next = NULL;
 594        p->pack_base = NULL;
 595        p->pack_last_used = 0;
 596        p->pack_use_cnt = 0;
 597        hashcpy(p->sha1, sha1);
 598        return p;
 599}
 600
 601void install_packed_git(struct packed_git *pack)
 602{
 603        pack->next = packed_git;
 604        packed_git = pack;
 605}
 606
 607static void prepare_packed_git_one(char *objdir, int local)
 608{
 609        char path[PATH_MAX];
 610        int len;
 611        DIR *dir;
 612        struct dirent *de;
 613
 614        sprintf(path, "%s/pack", objdir);
 615        len = strlen(path);
 616        dir = opendir(path);
 617        if (!dir) {
 618                if (errno != ENOENT)
 619                        error("unable to open object pack directory: %s: %s",
 620                              path, strerror(errno));
 621                return;
 622        }
 623        path[len++] = '/';
 624        while ((de = readdir(dir)) != NULL) {
 625                int namelen = strlen(de->d_name);
 626                struct packed_git *p;
 627
 628                if (!has_extension(de->d_name, ".idx"))
 629                        continue;
 630
 631                /* we have .idx.  Is it a file we can map? */
 632                strcpy(path + len, de->d_name);
 633                for (p = packed_git; p; p = p->next) {
 634                        if (!memcmp(path, p->pack_name, len + namelen - 4))
 635                                break;
 636                }
 637                if (p)
 638                        continue;
 639                p = add_packed_git(path, len + namelen, local);
 640                if (!p)
 641                        continue;
 642                p->next = packed_git;
 643                packed_git = p;
 644        }
 645        closedir(dir);
 646}
 647
 648static int prepare_packed_git_run_once = 0;
 649void prepare_packed_git(void)
 650{
 651        struct alternate_object_database *alt;
 652
 653        if (prepare_packed_git_run_once)
 654                return;
 655        prepare_packed_git_one(get_object_directory(), 1);
 656        prepare_alt_odb();
 657        for (alt = alt_odb_list; alt; alt = alt->next) {
 658                alt->name[-1] = 0;
 659                prepare_packed_git_one(alt->base, 0);
 660                alt->name[-1] = '/';
 661        }
 662        prepare_packed_git_run_once = 1;
 663}
 664
 665void reprepare_packed_git(void)
 666{
 667        prepare_packed_git_run_once = 0;
 668        prepare_packed_git();
 669}
 670
 671int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 672{
 673        unsigned char real_sha1[20];
 674        hash_sha1_file(map, size, type, real_sha1);
 675        return hashcmp(sha1, real_sha1) ? -1 : 0;
 676}
 677
 678void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 679{
 680        struct stat st;
 681        void *map;
 682        int fd;
 683        char *filename = find_sha1_file(sha1, &st);
 684
 685        if (!filename) {
 686                return NULL;
 687        }
 688
 689        fd = open(filename, O_RDONLY | sha1_file_open_flag);
 690        if (fd < 0) {
 691                /* See if it works without O_NOATIME */
 692                switch (sha1_file_open_flag) {
 693                default:
 694                        fd = open(filename, O_RDONLY);
 695                        if (fd >= 0)
 696                                break;
 697                /* Fallthrough */
 698                case 0:
 699                        return NULL;
 700                }
 701
 702                /* If it failed once, it will probably fail again.
 703                 * Stop using O_NOATIME
 704                 */
 705                sha1_file_open_flag = 0;
 706        }
 707        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 708        close(fd);
 709        if (map == MAP_FAILED)
 710                return NULL;
 711        *size = st.st_size;
 712        return map;
 713}
 714
 715int legacy_loose_object(unsigned char *map)
 716{
 717        unsigned int word;
 718
 719        /*
 720         * Is it a zlib-compressed buffer? If so, the first byte
 721         * must be 0x78 (15-bit window size, deflated), and the
 722         * first 16-bit word is evenly divisible by 31
 723         */
 724        word = (map[0] << 8) + map[1];
 725        if (map[0] == 0x78 && !(word % 31))
 726                return 1;
 727        else
 728                return 0;
 729}
 730
 731unsigned long unpack_object_header_gently(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep)
 732{
 733        unsigned shift;
 734        unsigned char c;
 735        unsigned long size;
 736        unsigned long used = 0;
 737
 738        c = buf[used++];
 739        *type = (c >> 4) & 7;
 740        size = c & 15;
 741        shift = 4;
 742        while (c & 0x80) {
 743                if (len <= used)
 744                        return 0;
 745                if (sizeof(long) * 8 <= shift)
 746                        return 0;
 747                c = buf[used++];
 748                size += (c & 0x7f) << shift;
 749                shift += 7;
 750        }
 751        *sizep = size;
 752        return used;
 753}
 754
 755static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 756{
 757        unsigned long size, used;
 758        static const char valid_loose_object_type[8] = {
 759                0, /* OBJ_EXT */
 760                1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
 761                0, /* "delta" and others are invalid in a loose object */
 762        };
 763        enum object_type type;
 764
 765        /* Get the data stream */
 766        memset(stream, 0, sizeof(*stream));
 767        stream->next_in = map;
 768        stream->avail_in = mapsize;
 769        stream->next_out = buffer;
 770        stream->avail_out = bufsiz;
 771
 772        if (legacy_loose_object(map)) {
 773                inflateInit(stream);
 774                return inflate(stream, 0);
 775        }
 776
 777        used = unpack_object_header_gently(map, mapsize, &type, &size);
 778        if (!used || !valid_loose_object_type[type])
 779                return -1;
 780        map += used;
 781        mapsize -= used;
 782
 783        /* Set up the stream for the rest.. */
 784        stream->next_in = map;
 785        stream->avail_in = mapsize;
 786        inflateInit(stream);
 787
 788        /* And generate the fake traditional header */
 789        stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
 790                                         type_names[type], size);
 791        return 0;
 792}
 793
 794static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 795{
 796        int bytes = strlen(buffer) + 1;
 797        unsigned char *buf = xmalloc(1+size);
 798        unsigned long n;
 799
 800        n = stream->total_out - bytes;
 801        if (n > size)
 802                n = size;
 803        memcpy(buf, (char *) buffer + bytes, n);
 804        bytes = n;
 805        if (bytes < size) {
 806                stream->next_out = buf + bytes;
 807                stream->avail_out = size - bytes;
 808                while (inflate(stream, Z_FINISH) == Z_OK)
 809                        /* nothing */;
 810        }
 811        buf[size] = 0;
 812        inflateEnd(stream);
 813        return buf;
 814}
 815
 816/*
 817 * We used to just use "sscanf()", but that's actually way
 818 * too permissive for what we want to check. So do an anal
 819 * object header parse by hand.
 820 */
 821static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 822{
 823        int i;
 824        unsigned long size;
 825
 826        /*
 827         * The type can be at most ten bytes (including the 
 828         * terminating '\0' that we add), and is followed by
 829         * a space. 
 830         */
 831        i = 10;
 832        for (;;) {
 833                char c = *hdr++;
 834                if (c == ' ')
 835                        break;
 836                if (!--i)
 837                        return -1;
 838                *type++ = c;
 839        }
 840        *type = 0;
 841
 842        /*
 843         * The length must follow immediately, and be in canonical
 844         * decimal format (ie "010" is not valid).
 845         */
 846        size = *hdr++ - '0';
 847        if (size > 9)
 848                return -1;
 849        if (size) {
 850                for (;;) {
 851                        unsigned long c = *hdr - '0';
 852                        if (c > 9)
 853                                break;
 854                        hdr++;
 855                        size = size * 10 + c;
 856                }
 857        }
 858        *sizep = size;
 859
 860        /*
 861         * The length must be followed by a zero byte
 862         */
 863        return *hdr ? -1 : 0;
 864}
 865
 866void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 867{
 868        int ret;
 869        z_stream stream;
 870        char hdr[8192];
 871
 872        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 873        if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 874                return NULL;
 875
 876        return unpack_sha1_rest(&stream, hdr, *size);
 877}
 878
 879static unsigned long get_delta_base(struct packed_git *p,
 880                                    unsigned long offset,
 881                                    enum object_type kind,
 882                                    unsigned long delta_obj_offset,
 883                                    unsigned long *base_obj_offset)
 884{
 885        unsigned char *base_info = (unsigned char *) p->pack_base + offset;
 886        unsigned long base_offset;
 887
 888        /* there must be at least 20 bytes left regardless of delta type */
 889        if (p->pack_size <= offset + 20)
 890                die("truncated pack file");
 891
 892        if (kind == OBJ_OFS_DELTA) {
 893                unsigned used = 0;
 894                unsigned char c = base_info[used++];
 895                base_offset = c & 127;
 896                while (c & 128) {
 897                        base_offset += 1;
 898                        if (!base_offset || base_offset & ~(~0UL >> 7))
 899                                die("offset value overflow for delta base object");
 900                        c = base_info[used++];
 901                        base_offset = (base_offset << 7) + (c & 127);
 902                }
 903                base_offset = delta_obj_offset - base_offset;
 904                if (base_offset >= delta_obj_offset)
 905                        die("delta base offset out of bound");
 906                offset += used;
 907        } else if (kind == OBJ_REF_DELTA) {
 908                /* The base entry _must_ be in the same pack */
 909                base_offset = find_pack_entry_one(base_info, p);
 910                if (!base_offset)
 911                        die("failed to find delta-pack base object %s",
 912                                sha1_to_hex(base_info));
 913                offset += 20;
 914        } else
 915                die("I am totally screwed");
 916        *base_obj_offset = base_offset;
 917        return offset;
 918}
 919
 920/* forward declaration for a mutually recursive function */
 921static int packed_object_info(struct packed_git *p, unsigned long offset,
 922                              char *type, unsigned long *sizep);
 923
 924static int packed_delta_info(struct packed_git *p,
 925                             unsigned long offset,
 926                             enum object_type kind,
 927                             unsigned long obj_offset,
 928                             char *type,
 929                             unsigned long *sizep)
 930{
 931        unsigned long base_offset;
 932
 933        offset = get_delta_base(p, offset, kind, obj_offset, &base_offset);
 934
 935        /* We choose to only get the type of the base object and
 936         * ignore potentially corrupt pack file that expects the delta
 937         * based on a base with a wrong size.  This saves tons of
 938         * inflate() calls.
 939         */
 940        if (packed_object_info(p, base_offset, type, NULL))
 941                die("cannot get info for delta-pack base");
 942
 943        if (sizep) {
 944                const unsigned char *data;
 945                unsigned char delta_head[20];
 946                unsigned long result_size;
 947                z_stream stream;
 948                int st;
 949
 950                memset(&stream, 0, sizeof(stream));
 951
 952                stream.next_in = (unsigned char *) p->pack_base + offset;
 953                stream.avail_in = p->pack_size - offset;
 954                stream.next_out = delta_head;
 955                stream.avail_out = sizeof(delta_head);
 956
 957                inflateInit(&stream);
 958                st = inflate(&stream, Z_FINISH);
 959                inflateEnd(&stream);
 960                if ((st != Z_STREAM_END) &&
 961                    stream.total_out != sizeof(delta_head))
 962                        die("delta data unpack-initial failed");
 963
 964                /* Examine the initial part of the delta to figure out
 965                 * the result size.
 966                 */
 967                data = delta_head;
 968
 969                /* ignore base size */
 970                get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 971
 972                /* Read the result size */
 973                result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 974                *sizep = result_size;
 975        }
 976        return 0;
 977}
 978
 979static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 980        enum object_type *type, unsigned long *sizep)
 981{
 982        unsigned long used;
 983
 984        if (p->pack_size <= offset)
 985                die("object offset outside of pack file");
 986
 987        used = unpack_object_header_gently((unsigned char *)p->pack_base +
 988                                           offset,
 989                                           p->pack_size - offset, type, sizep);
 990        if (!used)
 991                die("object offset outside of pack file");
 992
 993        return offset + used;
 994}
 995
 996void packed_object_info_detail(struct packed_git *p,
 997                               unsigned long offset,
 998                               char *type,
 999                               unsigned long *size,
1000                               unsigned long *store_size,
1001                               unsigned int *delta_chain_length,
1002                               unsigned char *base_sha1)
1003{
1004        unsigned long obj_offset, val;
1005        unsigned char *next_sha1;
1006        enum object_type kind;
1007
1008        *delta_chain_length = 0;
1009        obj_offset = offset;
1010        offset = unpack_object_header(p, offset, &kind, size);
1011
1012        for (;;) {
1013                switch (kind) {
1014                default:
1015                        die("pack %s contains unknown object type %d",
1016                            p->pack_name, kind);
1017                case OBJ_COMMIT:
1018                case OBJ_TREE:
1019                case OBJ_BLOB:
1020                case OBJ_TAG:
1021                        strcpy(type, type_names[kind]);
1022                        *store_size = 0; /* notyet */
1023                        return;
1024                case OBJ_OFS_DELTA:
1025                        get_delta_base(p, offset, kind, obj_offset, &offset);
1026                        if (*delta_chain_length == 0) {
1027                                /* TODO: find base_sha1 as pointed by offset */
1028                        }
1029                        break;
1030                case OBJ_REF_DELTA:
1031                        if (p->pack_size <= offset + 20)
1032                                die("pack file %s records an incomplete delta base",
1033                                    p->pack_name);
1034                        next_sha1 = (unsigned char *) p->pack_base + offset;
1035                        if (*delta_chain_length == 0)
1036                                hashcpy(base_sha1, next_sha1);
1037                        offset = find_pack_entry_one(next_sha1, p);
1038                        break;
1039                }
1040                obj_offset = offset;
1041                offset = unpack_object_header(p, offset, &kind, &val);
1042                (*delta_chain_length)++;
1043        }
1044}
1045
1046static int packed_object_info(struct packed_git *p, unsigned long offset,
1047                              char *type, unsigned long *sizep)
1048{
1049        unsigned long size, obj_offset = offset;
1050        enum object_type kind;
1051
1052        offset = unpack_object_header(p, offset, &kind, &size);
1053
1054        switch (kind) {
1055        case OBJ_OFS_DELTA:
1056        case OBJ_REF_DELTA:
1057                return packed_delta_info(p, offset, kind, obj_offset, type, sizep);
1058        case OBJ_COMMIT:
1059        case OBJ_TREE:
1060        case OBJ_BLOB:
1061        case OBJ_TAG:
1062                strcpy(type, type_names[kind]);
1063                break;
1064        default:
1065                die("pack %s contains unknown object type %d",
1066                    p->pack_name, kind);
1067        }
1068        if (sizep)
1069                *sizep = size;
1070        return 0;
1071}
1072
1073static void *unpack_compressed_entry(struct packed_git *p,
1074                                    unsigned long offset,
1075                                    unsigned long size)
1076{
1077        int st;
1078        z_stream stream;
1079        unsigned char *buffer;
1080
1081        buffer = xmalloc(size + 1);
1082        buffer[size] = 0;
1083        memset(&stream, 0, sizeof(stream));
1084        stream.next_in = (unsigned char*)p->pack_base + offset;
1085        stream.avail_in = p->pack_size - offset;
1086        stream.next_out = buffer;
1087        stream.avail_out = size;
1088
1089        inflateInit(&stream);
1090        st = inflate(&stream, Z_FINISH);
1091        inflateEnd(&stream);
1092        if ((st != Z_STREAM_END) || stream.total_out != size) {
1093                free(buffer);
1094                return NULL;
1095        }
1096
1097        return buffer;
1098}
1099
1100static void *unpack_delta_entry(struct packed_git *p,
1101                                unsigned long offset,
1102                                unsigned long delta_size,
1103                                enum object_type kind,
1104                                unsigned long obj_offset,
1105                                char *type,
1106                                unsigned long *sizep)
1107{
1108        void *delta_data, *result, *base;
1109        unsigned long result_size, base_size, base_offset;
1110
1111        offset = get_delta_base(p, offset, kind, obj_offset, &base_offset);
1112        base = unpack_entry(p, base_offset, type, &base_size);
1113        if (!base)
1114                die("failed to read delta base object at %lu from %s",
1115                    base_offset, p->pack_name);
1116
1117        delta_data = unpack_compressed_entry(p, offset, delta_size);
1118        result = patch_delta(base, base_size,
1119                             delta_data, delta_size,
1120                             &result_size);
1121        if (!result)
1122                die("failed to apply delta");
1123        free(delta_data);
1124        free(base);
1125        *sizep = result_size;
1126        return result;
1127}
1128
1129void *unpack_entry(struct packed_git *p, unsigned long offset,
1130                          char *type, unsigned long *sizep)
1131{
1132        unsigned long size, obj_offset = offset;
1133        enum object_type kind;
1134        void *retval;
1135
1136        if (use_packed_git(p))
1137                die("cannot map packed file");
1138        offset = unpack_object_header(p, offset, &kind, &size);
1139        switch (kind) {
1140        case OBJ_OFS_DELTA:
1141        case OBJ_REF_DELTA:
1142                retval = unpack_delta_entry(p, offset, size, kind, obj_offset, type, sizep);
1143                break;
1144        case OBJ_COMMIT:
1145        case OBJ_TREE:
1146        case OBJ_BLOB:
1147        case OBJ_TAG:
1148                strcpy(type, type_names[kind]);
1149                *sizep = size;
1150                retval = unpack_compressed_entry(p, offset, size);
1151                break;
1152        default:
1153                die("unknown object type %i in %s", kind, p->pack_name);
1154        }
1155        unuse_packed_git(p);
1156        return retval;
1157}
1158
1159int num_packed_objects(const struct packed_git *p)
1160{
1161        /* See check_packed_git_idx() */
1162        return (p->index_size - 20 - 20 - 4*256) / 24;
1163}
1164
1165int nth_packed_object_sha1(const struct packed_git *p, int n,
1166                           unsigned char* sha1)
1167{
1168        void *index = p->index_base + 256;
1169        if (n < 0 || num_packed_objects(p) <= n)
1170                return -1;
1171        hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
1172        return 0;
1173}
1174
1175unsigned long find_pack_entry_one(const unsigned char *sha1,
1176                                  struct packed_git *p)
1177{
1178        unsigned int *level1_ofs = p->index_base;
1179        int hi = ntohl(level1_ofs[*sha1]);
1180        int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1181        void *index = p->index_base + 256;
1182
1183        do {
1184                int mi = (lo + hi) / 2;
1185                int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
1186                if (!cmp)
1187                        return ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
1188                if (cmp > 0)
1189                        hi = mi;
1190                else
1191                        lo = mi+1;
1192        } while (lo < hi);
1193        return 0;
1194}
1195
1196static int matches_pack_name(struct packed_git *p, const char *ig)
1197{
1198        const char *last_c, *c;
1199
1200        if (!strcmp(p->pack_name, ig))
1201                return 0;
1202
1203        for (c = p->pack_name, last_c = c; *c;)
1204                if (*c == '/')
1205                        last_c = ++c;
1206                else
1207                        ++c;
1208        if (!strcmp(last_c, ig))
1209                return 0;
1210
1211        return 1;
1212}
1213
1214static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
1215{
1216        struct packed_git *p;
1217        unsigned long offset;
1218
1219        prepare_packed_git();
1220
1221        for (p = packed_git; p; p = p->next) {
1222                if (ignore_packed) {
1223                        const char **ig;
1224                        for (ig = ignore_packed; *ig; ig++)
1225                                if (!matches_pack_name(p, *ig))
1226                                        break;
1227                        if (*ig)
1228                                continue;
1229                }
1230                offset = find_pack_entry_one(sha1, p);
1231                if (offset) {
1232                        e->offset = offset;
1233                        e->p = p;
1234                        hashcpy(e->sha1, sha1);
1235                        return 1;
1236                }
1237        }
1238        return 0;
1239}
1240
1241struct packed_git *find_sha1_pack(const unsigned char *sha1, 
1242                                  struct packed_git *packs)
1243{
1244        struct packed_git *p;
1245
1246        for (p = packs; p; p = p->next) {
1247                if (find_pack_entry_one(sha1, p))
1248                        return p;
1249        }
1250        return NULL;
1251        
1252}
1253
1254static int sha1_loose_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1255{
1256        int status;
1257        unsigned long mapsize, size;
1258        void *map;
1259        z_stream stream;
1260        char hdr[128];
1261
1262        map = map_sha1_file(sha1, &mapsize);
1263        if (!map)
1264                return error("unable to find %s", sha1_to_hex(sha1));
1265        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1266                status = error("unable to unpack %s header",
1267                               sha1_to_hex(sha1));
1268        if (parse_sha1_header(hdr, type, &size) < 0)
1269                status = error("unable to parse %s header", sha1_to_hex(sha1));
1270        else {
1271                status = 0;
1272                if (sizep)
1273                        *sizep = size;
1274        }
1275        inflateEnd(&stream);
1276        munmap(map, mapsize);
1277        return status;
1278}
1279
1280int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1281{
1282        int status;
1283        struct pack_entry e;
1284
1285        if (!find_pack_entry(sha1, &e, NULL)) {
1286                reprepare_packed_git();
1287                if (!find_pack_entry(sha1, &e, NULL))
1288                        return sha1_loose_object_info(sha1, type, sizep);
1289        }
1290        if (use_packed_git(e.p))
1291                die("cannot map packed file");
1292        status = packed_object_info(e.p, e.offset, type, sizep);
1293        unuse_packed_git(e.p);
1294        return status;
1295}
1296
1297static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1298{
1299        struct pack_entry e;
1300
1301        if (!find_pack_entry(sha1, &e, NULL)) {
1302                error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1303                return NULL;
1304        }
1305        return unpack_entry(e.p, e.offset, type, size);
1306}
1307
1308void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1309{
1310        unsigned long mapsize;
1311        void *map, *buf;
1312        struct pack_entry e;
1313
1314        if (find_pack_entry(sha1, &e, NULL))
1315                return read_packed_sha1(sha1, type, size);
1316        map = map_sha1_file(sha1, &mapsize);
1317        if (map) {
1318                buf = unpack_sha1_file(map, mapsize, type, size);
1319                munmap(map, mapsize);
1320                return buf;
1321        }
1322        reprepare_packed_git();
1323        if (find_pack_entry(sha1, &e, NULL))
1324                return read_packed_sha1(sha1, type, size);
1325        return NULL;
1326}
1327
1328void *read_object_with_reference(const unsigned char *sha1,
1329                                 const char *required_type,
1330                                 unsigned long *size,
1331                                 unsigned char *actual_sha1_return)
1332{
1333        char type[20];
1334        void *buffer;
1335        unsigned long isize;
1336        unsigned char actual_sha1[20];
1337
1338        hashcpy(actual_sha1, sha1);
1339        while (1) {
1340                int ref_length = -1;
1341                const char *ref_type = NULL;
1342
1343                buffer = read_sha1_file(actual_sha1, type, &isize);
1344                if (!buffer)
1345                        return NULL;
1346                if (!strcmp(type, required_type)) {
1347                        *size = isize;
1348                        if (actual_sha1_return)
1349                                hashcpy(actual_sha1_return, actual_sha1);
1350                        return buffer;
1351                }
1352                /* Handle references */
1353                else if (!strcmp(type, commit_type))
1354                        ref_type = "tree ";
1355                else if (!strcmp(type, tag_type))
1356                        ref_type = "object ";
1357                else {
1358                        free(buffer);
1359                        return NULL;
1360                }
1361                ref_length = strlen(ref_type);
1362
1363                if (memcmp(buffer, ref_type, ref_length) ||
1364                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1365                        free(buffer);
1366                        return NULL;
1367                }
1368                free(buffer);
1369                /* Now we have the ID of the referred-to object in
1370                 * actual_sha1.  Check again. */
1371        }
1372}
1373
1374static void write_sha1_file_prepare(void *buf, unsigned long len,
1375                                    const char *type, unsigned char *sha1,
1376                                    unsigned char *hdr, int *hdrlen)
1377{
1378        SHA_CTX c;
1379
1380        /* Generate the header */
1381        *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1382
1383        /* Sha1.. */
1384        SHA1_Init(&c);
1385        SHA1_Update(&c, hdr, *hdrlen);
1386        SHA1_Update(&c, buf, len);
1387        SHA1_Final(sha1, &c);
1388}
1389
1390/*
1391 * Link the tempfile to the final place, possibly creating the
1392 * last directory level as you do so.
1393 *
1394 * Returns the errno on failure, 0 on success.
1395 */
1396static int link_temp_to_file(const char *tmpfile, const char *filename)
1397{
1398        int ret;
1399        char *dir;
1400
1401        if (!link(tmpfile, filename))
1402                return 0;
1403
1404        /*
1405         * Try to mkdir the last path component if that failed.
1406         *
1407         * Re-try the "link()" regardless of whether the mkdir
1408         * succeeds, since a race might mean that somebody
1409         * else succeeded.
1410         */
1411        ret = errno;
1412        dir = strrchr(filename, '/');
1413        if (dir) {
1414                *dir = 0;
1415                if (!mkdir(filename, 0777) && adjust_shared_perm(filename)) {
1416                        *dir = '/';
1417                        return -2;
1418                }
1419                *dir = '/';
1420                if (!link(tmpfile, filename))
1421                        return 0;
1422                ret = errno;
1423        }
1424        return ret;
1425}
1426
1427/*
1428 * Move the just written object into its final resting place
1429 */
1430int move_temp_to_file(const char *tmpfile, const char *filename)
1431{
1432        int ret = link_temp_to_file(tmpfile, filename);
1433
1434        /*
1435         * Coda hack - coda doesn't like cross-directory links,
1436         * so we fall back to a rename, which will mean that it
1437         * won't be able to check collisions, but that's not a
1438         * big deal.
1439         *
1440         * The same holds for FAT formatted media.
1441         *
1442         * When this succeeds, we just return 0. We have nothing
1443         * left to unlink.
1444         */
1445        if (ret && ret != EEXIST) {
1446                if (!rename(tmpfile, filename))
1447                        return 0;
1448                ret = errno;
1449        }
1450        unlink(tmpfile);
1451        if (ret) {
1452                if (ret != EEXIST) {
1453                        return error("unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1454                }
1455                /* FIXME!!! Collision check here ? */
1456        }
1457
1458        return 0;
1459}
1460
1461static int write_buffer(int fd, const void *buf, size_t len)
1462{
1463        while (len) {
1464                ssize_t size;
1465
1466                size = write(fd, buf, len);
1467                if (!size)
1468                        return error("file write: disk full");
1469                if (size < 0) {
1470                        if (errno == EINTR || errno == EAGAIN)
1471                                continue;
1472                        return error("file write error (%s)", strerror(errno));
1473                }
1474                len -= size;
1475                buf = (char *) buf + size;
1476        }
1477        return 0;
1478}
1479
1480static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1481{
1482        int hdr_len;
1483        unsigned char c;
1484
1485        c = (type << 4) | (len & 15);
1486        len >>= 4;
1487        hdr_len = 1;
1488        while (len) {
1489                *hdr++ = c | 0x80;
1490                hdr_len++;
1491                c = (len & 0x7f);
1492                len >>= 7;
1493        }
1494        *hdr = c;
1495        return hdr_len;
1496}
1497
1498static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1499{
1500        int obj_type, hdr;
1501
1502        if (use_legacy_headers) {
1503                while (deflate(stream, 0) == Z_OK)
1504                        /* nothing */;
1505                return;
1506        }
1507        if (!strcmp(type, blob_type))
1508                obj_type = OBJ_BLOB;
1509        else if (!strcmp(type, tree_type))
1510                obj_type = OBJ_TREE;
1511        else if (!strcmp(type, commit_type))
1512                obj_type = OBJ_COMMIT;
1513        else if (!strcmp(type, tag_type))
1514                obj_type = OBJ_TAG;
1515        else
1516                die("trying to generate bogus object of type '%s'", type);
1517        hdr = write_binary_header(stream->next_out, obj_type, len);
1518        stream->total_out = hdr;
1519        stream->next_out += hdr;
1520        stream->avail_out -= hdr;
1521}
1522
1523int hash_sha1_file(void *buf, unsigned long len, const char *type,
1524                   unsigned char *sha1)
1525{
1526        unsigned char hdr[50];
1527        int hdrlen;
1528        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1529        return 0;
1530}
1531
1532int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1533{
1534        int size;
1535        unsigned char *compressed;
1536        z_stream stream;
1537        unsigned char sha1[20];
1538        char *filename;
1539        static char tmpfile[PATH_MAX];
1540        unsigned char hdr[50];
1541        int fd, hdrlen;
1542
1543        /* Normally if we have it in the pack then we do not bother writing
1544         * it out into .git/objects/??/?{38} file.
1545         */
1546        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1547        filename = sha1_file_name(sha1);
1548        if (returnsha1)
1549                hashcpy(returnsha1, sha1);
1550        if (has_sha1_file(sha1))
1551                return 0;
1552        fd = open(filename, O_RDONLY);
1553        if (fd >= 0) {
1554                /*
1555                 * FIXME!!! We might do collision checking here, but we'd
1556                 * need to uncompress the old file and check it. Later.
1557                 */
1558                close(fd);
1559                return 0;
1560        }
1561
1562        if (errno != ENOENT) {
1563                return error("sha1 file %s: %s\n", filename, strerror(errno));
1564        }
1565
1566        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1567
1568        fd = mkstemp(tmpfile);
1569        if (fd < 0) {
1570                if (errno == EPERM)
1571                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1572                else
1573                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1574        }
1575
1576        /* Set it up */
1577        memset(&stream, 0, sizeof(stream));
1578        deflateInit(&stream, zlib_compression_level);
1579        size = 8 + deflateBound(&stream, len+hdrlen);
1580        compressed = xmalloc(size);
1581
1582        /* Compress it */
1583        stream.next_out = compressed;
1584        stream.avail_out = size;
1585
1586        /* First header.. */
1587        stream.next_in = hdr;
1588        stream.avail_in = hdrlen;
1589        setup_object_header(&stream, type, len);
1590
1591        /* Then the data itself.. */
1592        stream.next_in = buf;
1593        stream.avail_in = len;
1594        while (deflate(&stream, Z_FINISH) == Z_OK)
1595                /* nothing */;
1596        deflateEnd(&stream);
1597        size = stream.total_out;
1598
1599        if (write_buffer(fd, compressed, size) < 0)
1600                die("unable to write sha1 file");
1601        fchmod(fd, 0444);
1602        close(fd);
1603        free(compressed);
1604
1605        return move_temp_to_file(tmpfile, filename);
1606}
1607
1608/*
1609 * We need to unpack and recompress the object for writing
1610 * it out to a different file.
1611 */
1612static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1613{
1614        size_t size;
1615        z_stream stream;
1616        unsigned char *unpacked;
1617        unsigned long len;
1618        char type[20];
1619        char hdr[50];
1620        int hdrlen;
1621        void *buf;
1622
1623        /* need to unpack and recompress it by itself */
1624        unpacked = read_packed_sha1(sha1, type, &len);
1625
1626        hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1627
1628        /* Set it up */
1629        memset(&stream, 0, sizeof(stream));
1630        deflateInit(&stream, zlib_compression_level);
1631        size = deflateBound(&stream, len + hdrlen);
1632        buf = xmalloc(size);
1633
1634        /* Compress it */
1635        stream.next_out = buf;
1636        stream.avail_out = size;
1637
1638        /* First header.. */
1639        stream.next_in = (void *)hdr;
1640        stream.avail_in = hdrlen;
1641        while (deflate(&stream, 0) == Z_OK)
1642                /* nothing */;
1643
1644        /* Then the data itself.. */
1645        stream.next_in = unpacked;
1646        stream.avail_in = len;
1647        while (deflate(&stream, Z_FINISH) == Z_OK)
1648                /* nothing */;
1649        deflateEnd(&stream);
1650        free(unpacked);
1651
1652        *objsize = stream.total_out;
1653        return buf;
1654}
1655
1656int write_sha1_to_fd(int fd, const unsigned char *sha1)
1657{
1658        int retval;
1659        unsigned long objsize;
1660        void *buf = map_sha1_file(sha1, &objsize);
1661
1662        if (buf) {
1663                retval = write_buffer(fd, buf, objsize);
1664                munmap(buf, objsize);
1665                return retval;
1666        }
1667
1668        buf = repack_object(sha1, &objsize);
1669        retval = write_buffer(fd, buf, objsize);
1670        free(buf);
1671        return retval;
1672}
1673
1674int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1675                       size_t bufsize, size_t *bufposn)
1676{
1677        char tmpfile[PATH_MAX];
1678        int local;
1679        z_stream stream;
1680        unsigned char real_sha1[20];
1681        unsigned char discard[4096];
1682        int ret;
1683        SHA_CTX c;
1684
1685        snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1686
1687        local = mkstemp(tmpfile);
1688        if (local < 0) {
1689                if (errno == EPERM)
1690                        return error("insufficient permission for adding an object to repository database %s\n", get_object_directory());
1691                else
1692                        return error("unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1693        }
1694
1695        memset(&stream, 0, sizeof(stream));
1696
1697        inflateInit(&stream);
1698
1699        SHA1_Init(&c);
1700
1701        do {
1702                ssize_t size;
1703                if (*bufposn) {
1704                        stream.avail_in = *bufposn;
1705                        stream.next_in = (unsigned char *) buffer;
1706                        do {
1707                                stream.next_out = discard;
1708                                stream.avail_out = sizeof(discard);
1709                                ret = inflate(&stream, Z_SYNC_FLUSH);
1710                                SHA1_Update(&c, discard, sizeof(discard) -
1711                                            stream.avail_out);
1712                        } while (stream.avail_in && ret == Z_OK);
1713                        if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1714                                die("unable to write sha1 file");
1715                        memmove(buffer, buffer + *bufposn - stream.avail_in,
1716                                stream.avail_in);
1717                        *bufposn = stream.avail_in;
1718                        if (ret != Z_OK)
1719                                break;
1720                }
1721                size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1722                if (size <= 0) {
1723                        close(local);
1724                        unlink(tmpfile);
1725                        if (!size)
1726                                return error("Connection closed?");
1727                        perror("Reading from connection");
1728                        return -1;
1729                }
1730                *bufposn += size;
1731        } while (1);
1732        inflateEnd(&stream);
1733
1734        close(local);
1735        SHA1_Final(real_sha1, &c);
1736        if (ret != Z_STREAM_END) {
1737                unlink(tmpfile);
1738                return error("File %s corrupted", sha1_to_hex(sha1));
1739        }
1740        if (hashcmp(sha1, real_sha1)) {
1741                unlink(tmpfile);
1742                return error("File %s has bad hash", sha1_to_hex(sha1));
1743        }
1744
1745        return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1746}
1747
1748int has_pack_index(const unsigned char *sha1)
1749{
1750        struct stat st;
1751        if (stat(sha1_pack_index_name(sha1), &st))
1752                return 0;
1753        return 1;
1754}
1755
1756int has_pack_file(const unsigned char *sha1)
1757{
1758        struct stat st;
1759        if (stat(sha1_pack_name(sha1), &st))
1760                return 0;
1761        return 1;
1762}
1763
1764int has_sha1_pack(const unsigned char *sha1, const char **ignore_packed)
1765{
1766        struct pack_entry e;
1767        return find_pack_entry(sha1, &e, ignore_packed);
1768}
1769
1770int has_sha1_file(const unsigned char *sha1)
1771{
1772        struct stat st;
1773        struct pack_entry e;
1774
1775        if (find_pack_entry(sha1, &e, NULL))
1776                return 1;
1777        return find_sha1_file(sha1, &st) ? 1 : 0;
1778}
1779
1780/*
1781 * reads from fd as long as possible into a supplied buffer of size bytes.
1782 * If necessary the buffer's size is increased using realloc()
1783 *
1784 * returns 0 if anything went fine and -1 otherwise
1785 *
1786 * NOTE: both buf and size may change, but even when -1 is returned
1787 * you still have to free() it yourself.
1788 */
1789int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1790{
1791        char* buf = *return_buf;
1792        unsigned long size = *return_size;
1793        int iret;
1794        unsigned long off = 0;
1795
1796        do {
1797                iret = xread(fd, buf + off, size - off);
1798                if (iret > 0) {
1799                        off += iret;
1800                        if (off == size) {
1801                                size *= 2;
1802                                buf = xrealloc(buf, size);
1803                        }
1804                }
1805        } while (iret > 0);
1806
1807        *return_buf = buf;
1808        *return_size = off;
1809
1810        if (iret < 0)
1811                return -1;
1812        return 0;
1813}
1814
1815int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1816{
1817        unsigned long size = 4096;
1818        char *buf = xmalloc(size);
1819        int ret;
1820
1821        if (read_pipe(fd, &buf, &size)) {
1822                free(buf);
1823                return -1;
1824        }
1825
1826        if (!type)
1827                type = blob_type;
1828        if (write_object)
1829                ret = write_sha1_file(buf, size, type, sha1);
1830        else
1831                ret = hash_sha1_file(buf, size, type, sha1);
1832        free(buf);
1833        return ret;
1834}
1835
1836int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1837{
1838        unsigned long size = st->st_size;
1839        void *buf;
1840        int ret;
1841
1842        buf = "";
1843        if (size)
1844                buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1845        close(fd);
1846        if (buf == MAP_FAILED)
1847                return -1;
1848
1849        if (!type)
1850                type = blob_type;
1851        if (write_object)
1852                ret = write_sha1_file(buf, size, type, sha1);
1853        else
1854                ret = hash_sha1_file(buf, size, type, sha1);
1855        if (size)
1856                munmap(buf, size);
1857        return ret;
1858}
1859
1860int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1861{
1862        int fd;
1863        char *target;
1864
1865        switch (st->st_mode & S_IFMT) {
1866        case S_IFREG:
1867                fd = open(path, O_RDONLY);
1868                if (fd < 0)
1869                        return error("open(\"%s\"): %s", path,
1870                                     strerror(errno));
1871                if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1872                        return error("%s: failed to insert into database",
1873                                     path);
1874                break;
1875        case S_IFLNK:
1876                target = xmalloc(st->st_size+1);
1877                if (readlink(path, target, st->st_size+1) != st->st_size) {
1878                        char *errstr = strerror(errno);
1879                        free(target);
1880                        return error("readlink(\"%s\"): %s", path,
1881                                     errstr);
1882                }
1883                if (!write_object)
1884                        hash_sha1_file(target, st->st_size, blob_type, sha1);
1885                else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1886                        return error("%s: failed to insert into database",
1887                                     path);
1888                free(target);
1889                break;
1890        default:
1891                return error("%s: unsupported file type", path);
1892        }
1893        return 0;
1894}