setup.c

   1 #include "cache.h"
   2 #include "dir.h"
   3
   4 static int inside_git_dir = -1;
   5 static int inside_work_tree = -1;
   6
   7 static char *prefix_path_gently(const char *prefix, int len, const char *path)
   8 {
   9         const char *orig = path;
  10         char *sanitized;
  11         if (is_absolute_path(orig)) {
  12                 const char *temp = real_path(path);
  13                 sanitized = xmalloc(len + strlen(temp) + 1);
  14                 strcpy(sanitized, temp);
  15         } else {
  16                 sanitized = xmalloc(len + strlen(path) + 1);
  17                 if (len)
  18                         memcpy(sanitized, prefix, len);
  19                 strcpy(sanitized + len, path);
  20         }
  21         if (normalize_path_copy(sanitized, sanitized))
  22                 goto error_out;
  23         if (is_absolute_path(orig)) {
  24                 size_t root_len, len, total;
  25                 const char *work_tree = get_git_work_tree();
  26                 if (!work_tree)
  27                         goto error_out;
  28                 len = strlen(work_tree);
  29                 root_len = offset_1st_component(work_tree);
  30                 total = strlen(sanitized) + 1;
  31                 if (strncmp(sanitized, work_tree, len) ||
  32                     (len > root_len && sanitized[len] != '\0' && sanitized[len] != '/')) {
  33                 error_out:
  34                         free(sanitized);
  35                         return NULL;
  36                 }
  37                 if (sanitized[len] == '/')
  38                         len++;
  39                 memmove(sanitized, sanitized + len, total - len);
  40         }
  41         return sanitized;
  42 }
  43
  44 char *prefix_path(const char *prefix, int len, const char *path)
  45 {
  46         char *r = prefix_path_gently(prefix, len, path);
  47         if (!r)
  48                 die("'%s' is outside repository", path);
  49         return r;
  50 }
  51
  52 int path_inside_repo(const char *prefix, const char *path)
  53 {
  54         int len = prefix ? strlen(prefix) : 0;
  55         char *r = prefix_path_gently(prefix, len, path);
  56         if (r) {
  57                 free(r);
  58                 return 1;
  59         }
  60         return 0;
  61 }
  62
  63 int check_filename(const char *prefix, const char *arg)
  64 {
  65         const char *name;
  66         struct stat st;
  67
  68         name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
  69         if (!lstat(name, &st))
  70                 return 1; /* file exists */
  71         if (errno == ENOENT || errno == ENOTDIR)
  72                 return 0; /* file does not exist */
  73         die_errno("failed to stat '%s'", arg);
  74 }
  75
  76 static void NORETURN die_verify_filename(const char *prefix,
  77                                          const char *arg,
  78                                          int diagnose_misspelt_rev)
  79 {
  80         if (!diagnose_misspelt_rev)
  81                 die("%s: no such path in the working tree.\n"
  82                     "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
  83                     arg);
  84         /*
  85          * Saying "'(icase)foo' does not exist in the index" when the
  86          * user gave us ":(icase)foo" is just stupid.  A magic pathspec
  87          * begins with a colon and is followed by a non-alnum; do not
  88          * let maybe_die_on_misspelt_object_name() even trigger.
  89          */
  90         if (!(arg[0] == ':' && !isalnum(arg[1])))
  91                 maybe_die_on_misspelt_object_name(arg, prefix);
  92
  93         /* ... or fall back the most general message. */
  94         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
  95             "Use '--' to separate paths from revisions, like this:\n"
  96             "'git <command> [<revision>...] -- [<file>...]'", arg);
  97
  98 }
  99
 100 /*
 101  * Verify a filename that we got as an argument for a pathspec
 102  * entry. Note that a filename that begins with "-" never verifies
 103  * as true, because even if such a filename were to exist, we want
 104  * it to be preceded by the "--" marker (or we want the user to
 105  * use a format like "./-filename")
 106  *
 107  * The "diagnose_misspelt_rev" is used to provide a user-friendly
 108  * diagnosis when dying upon finding that "name" is not a pathname.
 109  * If set to 1, the diagnosis will try to diagnose "name" as an
 110  * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 111  * will only complain about an inexisting file.
 112  *
 113  * This function is typically called to check that a "file or rev"
 114  * argument is unambiguous. In this case, the caller will want
 115  * diagnose_misspelt_rev == 1 when verifying the first non-rev
 116  * argument (which could have been a revision), and
 117  * diagnose_misspelt_rev == 0 for the next ones (because we already
 118  * saw a filename, there's not ambiguity anymore).
 119  */
 120 void verify_filename(const char *prefix,
 121                      const char *arg,
 122                      int diagnose_misspelt_rev)
 123 {
 124         if (*arg == '-')
 125                 die("bad flag '%s' used after filename", arg);
 126         if (check_filename(prefix, arg))
 127                 return;
 128         die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 129 }
 130
 131 /*
 132  * Opposite of the above: the command line did not have -- marker
 133  * and we parsed the arg as a refname.  It should not be interpretable
 134  * as a filename.
 135  */
 136 void verify_non_filename(const char *prefix, const char *arg)
 137 {
 138         if (!is_inside_work_tree() || is_inside_git_dir())
 139                 return;
 140         if (*arg == '-')
 141                 return; /* flag */
 142         if (!check_filename(prefix, arg))
 143                 return;
 144         die("ambiguous argument '%s': both revision and filename\n"
 145             "Use '--' to separate paths from revisions, like this:\n"
 146             "'git <command> [<revision>...] -- [<file>...]'", arg);
 147 }
 148
 149 /*
 150  * Magic pathspec
 151  *
 152  * NEEDSWORK: These need to be moved to dir.h or even to a new
 153  * pathspec.h when we restructure get_pathspec() users to use the
 154  * "struct pathspec" interface.
 155  *
 156  * Possible future magic semantics include stuff like:
 157  *
 158  *      { PATHSPEC_NOGLOB, '!', "noglob" },
 159  *      { PATHSPEC_ICASE, '\0', "icase" },
 160  *      { PATHSPEC_RECURSIVE, '*', "recursive" },
 161  *      { PATHSPEC_REGEXP, '\0', "regexp" },
 162  *
 163  */
 164 #define PATHSPEC_FROMTOP    (1<<0)
 165
 166 static struct pathspec_magic {
 167         unsigned bit;
 168         char mnemonic; /* this cannot be ':'! */
 169         const char *name;
 170 } pathspec_magic[] = {
 171         { PATHSPEC_FROMTOP, '/', "top" },
 172 };
 173
 174 /*
 175  * Take an element of a pathspec and check for magic signatures.
 176  * Append the result to the prefix.
 177  *
 178  * For now, we only parse the syntax and throw out anything other than
 179  * "top" magic.
 180  *
 181  * NEEDSWORK: This needs to be rewritten when we start migrating
 182  * get_pathspec() users to use the "struct pathspec" interface.  For
 183  * example, a pathspec element may be marked as case-insensitive, but
 184  * the prefix part must always match literally, and a single stupid
 185  * string cannot express such a case.
 186  */
 187 static const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
 188 {
 189         unsigned magic = 0;
 190         const char *copyfrom = elt;
 191         int i;
 192
 193         if (elt[0] != ':') {
 194                 ; /* nothing to do */
 195         } else if (elt[1] == '(') {
 196                 /* longhand */
 197                 const char *nextat;
 198                 for (copyfrom = elt + 2;
 199                      *copyfrom && *copyfrom != ')';
 200                      copyfrom = nextat) {
 201                         size_t len = strcspn(copyfrom, ",)");
 202                         if (copyfrom[len] == ')')
 203                                 nextat = copyfrom + len;
 204                         else
 205                                 nextat = copyfrom + len + 1;
 206                         if (!len)
 207                                 continue;
 208                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 209                                 if (strlen(pathspec_magic[i].name) == len &&
 210                                     !strncmp(pathspec_magic[i].name, copyfrom, len)) {
 211                                         magic |= pathspec_magic[i].bit;
 212                                         break;
 213                                 }
 214                         if (ARRAY_SIZE(pathspec_magic) <= i)
 215                                 die("Invalid pathspec magic '%.*s' in '%s'",
 216                                     (int) len, copyfrom, elt);
 217                 }
 218                 if (*copyfrom == ')')
 219                         copyfrom++;
 220         } else {
 221                 /* shorthand */
 222                 for (copyfrom = elt + 1;
 223                      *copyfrom && *copyfrom != ':';
 224                      copyfrom++) {
 225                         char ch = *copyfrom;
 226
 227                         if (!is_pathspec_magic(ch))
 228                                 break;
 229                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 230                                 if (pathspec_magic[i].mnemonic == ch) {
 231                                         magic |= pathspec_magic[i].bit;
 232                                         break;
 233                                 }
 234                         if (ARRAY_SIZE(pathspec_magic) <= i)
 235                                 die("Unimplemented pathspec magic '%c' in '%s'",
 236                                     ch, elt);
 237                 }
 238                 if (*copyfrom == ':')
 239                         copyfrom++;
 240         }
 241
 242         if (magic & PATHSPEC_FROMTOP)
 243                 return xstrdup(copyfrom);
 244         else
 245                 return prefix_path(prefix, prefixlen, copyfrom);
 246 }
 247
 248 const char **get_pathspec(const char *prefix, const char **pathspec)
 249 {
 250         const char *entry = *pathspec;
 251         const char **src, **dst;
 252         int prefixlen;
 253
 254         if (!prefix && !entry)
 255                 return NULL;
 256
 257         if (!entry) {
 258                 static const char *spec[2];
 259                 spec[0] = prefix;
 260                 spec[1] = NULL;
 261                 return spec;
 262         }
 263
 264         /* Otherwise we have to re-write the entries.. */
 265         src = pathspec;
 266         dst = pathspec;
 267         prefixlen = prefix ? strlen(prefix) : 0;
 268         while (*src) {
 269                 *(dst++) = prefix_pathspec(prefix, prefixlen, *src);
 270                 src++;
 271         }
 272         *dst = NULL;
 273         if (!*pathspec)
 274                 return NULL;
 275         return pathspec;
 276 }
 277
 278 /*
 279  * Test if it looks like we're at a git directory.
 280  * We want to see:
 281  *
 282  *  - either an objects/ directory _or_ the proper
 283  *    GIT_OBJECT_DIRECTORY environment variable
 284  *  - a refs/ directory
 285  *  - either a HEAD symlink or a HEAD file that is formatted as
 286  *    a proper "ref:", or a regular file HEAD that has a properly
 287  *    formatted sha1 object name.
 288  */
 289 int is_git_directory(const char *suspect)
 290 {
 291         char path[PATH_MAX];
 292         size_t len = strlen(suspect);
 293
 294         if (PATH_MAX <= len + strlen("/objects"))
 295                 die("Too long path: %.*s", 60, suspect);
 296         strcpy(path, suspect);
 297         if (getenv(DB_ENVIRONMENT)) {
 298                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 299                         return 0;
 300         }
 301         else {
 302                 strcpy(path + len, "/objects");
 303                 if (access(path, X_OK))
 304                         return 0;
 305         }
 306
 307         strcpy(path + len, "/refs");
 308         if (access(path, X_OK))
 309                 return 0;
 310
 311         strcpy(path + len, "/HEAD");
 312         if (validate_headref(path))
 313                 return 0;
 314
 315         return 1;
 316 }
 317
 318 int is_inside_git_dir(void)
 319 {
 320         if (inside_git_dir < 0)
 321                 inside_git_dir = is_inside_dir(get_git_dir());
 322         return inside_git_dir;
 323 }
 324
 325 int is_inside_work_tree(void)
 326 {
 327         if (inside_work_tree < 0)
 328                 inside_work_tree = is_inside_dir(get_git_work_tree());
 329         return inside_work_tree;
 330 }
 331
 332 void setup_work_tree(void)
 333 {
 334         const char *work_tree, *git_dir;
 335         static int initialized = 0;
 336
 337         if (initialized)
 338                 return;
 339         work_tree = get_git_work_tree();
 340         git_dir = get_git_dir();
 341         if (!is_absolute_path(git_dir))
 342                 git_dir = real_path(get_git_dir());
 343         if (!work_tree || chdir(work_tree))
 344                 die("This operation must be run in a work tree");
 345
 346         /*
 347          * Make sure subsequent git processes find correct worktree
 348          * if $GIT_WORK_TREE is set relative
 349          */
 350         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 351                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 352
 353         set_git_dir(relative_path(git_dir, work_tree));
 354         initialized = 1;
 355 }
 356
 357 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 358 {
 359         char repo_config[PATH_MAX+1];
 360
 361         /*
 362          * git_config() can't be used here because it calls git_pathdup()
 363          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 364          * set git_dir to ".git".
 365          *
 366          * We are in gitdir setup, no git dir has been found useable yet.
 367          * Use a gentler version of git_config() to check if this repo
 368          * is a good one.
 369          */
 370         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 371         git_config_early(check_repository_format_version, NULL, repo_config);
 372         if (GIT_REPO_VERSION < repository_format_version) {
 373                 if (!nongit_ok)
 374                         die ("Expected git repo version <= %d, found %d",
 375                              GIT_REPO_VERSION, repository_format_version);
 376                 warning("Expected git repo version <= %d, found %d",
 377                         GIT_REPO_VERSION, repository_format_version);
 378                 warning("Please upgrade Git");
 379                 *nongit_ok = -1;
 380                 return -1;
 381         }
 382         return 0;
 383 }
 384
 385 /*
 386  * Try to read the location of the git directory from the .git file,
 387  * return path to git directory if found.
 388  */
 389 const char *read_gitfile(const char *path)
 390 {
 391         char *buf;
 392         char *dir;
 393         const char *slash;
 394         struct stat st;
 395         int fd;
 396         ssize_t len;
 397
 398         if (stat(path, &st))
 399                 return NULL;
 400         if (!S_ISREG(st.st_mode))
 401                 return NULL;
 402         fd = open(path, O_RDONLY);
 403         if (fd < 0)
 404                 die_errno("Error opening '%s'", path);
 405         buf = xmalloc(st.st_size + 1);
 406         len = read_in_full(fd, buf, st.st_size);
 407         close(fd);
 408         if (len != st.st_size)
 409                 die("Error reading %s", path);
 410         buf[len] = '\0';
 411         if (prefixcmp(buf, "gitdir: "))
 412                 die("Invalid gitfile format: %s", path);
 413         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 414                 len--;
 415         if (len < 9)
 416                 die("No path in gitfile: %s", path);
 417         buf[len] = '\0';
 418         dir = buf + 8;
 419
 420         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 421                 size_t pathlen = slash+1 - path;
 422                 size_t dirlen = pathlen + len - 8;
 423                 dir = xmalloc(dirlen + 1);
 424                 strncpy(dir, path, pathlen);
 425                 strncpy(dir + pathlen, buf + 8, len - 8);
 426                 dir[dirlen] = '\0';
 427                 free(buf);
 428                 buf = dir;
 429         }
 430
 431         if (!is_git_directory(dir))
 432                 die("Not a git repository: %s", dir);
 433         path = real_path(dir);
 434
 435         free(buf);
 436         return path;
 437 }
 438
 439 static const char *setup_explicit_git_dir(const char *gitdirenv,
 440                                           char *cwd, int len,
 441                                           int *nongit_ok)
 442 {
 443         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 444         const char *worktree;
 445         char *gitfile;
 446         int offset;
 447
 448         if (PATH_MAX - 40 < strlen(gitdirenv))
 449                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 450
 451         gitfile = (char*)read_gitfile(gitdirenv);
 452         if (gitfile) {
 453                 gitfile = xstrdup(gitfile);
 454                 gitdirenv = gitfile;
 455         }
 456
 457         if (!is_git_directory(gitdirenv)) {
 458                 if (nongit_ok) {
 459                         *nongit_ok = 1;
 460                         free(gitfile);
 461                         return NULL;
 462                 }
 463                 die("Not a git repository: '%s'", gitdirenv);
 464         }
 465
 466         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 467                 free(gitfile);
 468                 return NULL;
 469         }
 470
 471         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 472         if (work_tree_env)
 473                 set_git_work_tree(work_tree_env);
 474         else if (is_bare_repository_cfg > 0) {
 475                 if (git_work_tree_cfg) /* #22.2, #30 */
 476                         die("core.bare and core.worktree do not make sense");
 477
 478                 /* #18, #26 */
 479                 set_git_dir(gitdirenv);
 480                 free(gitfile);
 481                 return NULL;
 482         }
 483         else if (git_work_tree_cfg) { /* #6, #14 */
 484                 if (is_absolute_path(git_work_tree_cfg))
 485                         set_git_work_tree(git_work_tree_cfg);
 486                 else {
 487                         char core_worktree[PATH_MAX];
 488                         if (chdir(gitdirenv))
 489                                 die_errno("Could not chdir to '%s'", gitdirenv);
 490                         if (chdir(git_work_tree_cfg))
 491                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 492                         if (!getcwd(core_worktree, PATH_MAX))
 493                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 494                         if (chdir(cwd))
 495                                 die_errno("Could not come back to cwd");
 496                         set_git_work_tree(core_worktree);
 497                 }
 498         }
 499         else /* #2, #10 */
 500                 set_git_work_tree(".");
 501
 502         /* set_git_work_tree() must have been called by now */
 503         worktree = get_git_work_tree();
 504
 505         /* both get_git_work_tree() and cwd are already normalized */
 506         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 507                 set_git_dir(gitdirenv);
 508                 free(gitfile);
 509                 return NULL;
 510         }
 511
 512         offset = dir_inside_of(cwd, worktree);
 513         if (offset >= 0) {      /* cwd inside worktree? */
 514                 set_git_dir(real_path(gitdirenv));
 515                 if (chdir(worktree))
 516                         die_errno("Could not chdir to '%s'", worktree);
 517                 cwd[len++] = '/';
 518                 cwd[len] = '\0';
 519                 free(gitfile);
 520                 return cwd + offset;
 521         }
 522
 523         /* cwd outside worktree */
 524         set_git_dir(gitdirenv);
 525         free(gitfile);
 526         return NULL;
 527 }
 528
 529 static const char *setup_discovered_git_dir(const char *gitdir,
 530                                             char *cwd, int offset, int len,
 531                                             int *nongit_ok)
 532 {
 533         if (check_repository_format_gently(gitdir, nongit_ok))
 534                 return NULL;
 535
 536         /* --work-tree is set without --git-dir; use discovered one */
 537         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 538                 if (offset != len && !is_absolute_path(gitdir))
 539                         gitdir = xstrdup(real_path(gitdir));
 540                 if (chdir(cwd))
 541                         die_errno("Could not come back to cwd");
 542                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 543         }
 544
 545         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 546         if (is_bare_repository_cfg > 0) {
 547                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 548                 if (chdir(cwd))
 549                         die_errno("Could not come back to cwd");
 550                 return NULL;
 551         }
 552
 553         /* #0, #1, #5, #8, #9, #12, #13 */
 554         set_git_work_tree(".");
 555         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 556                 set_git_dir(gitdir);
 557         inside_git_dir = 0;
 558         inside_work_tree = 1;
 559         if (offset == len)
 560                 return NULL;
 561
 562         /* Make "offset" point to past the '/', and add a '/' at the end */
 563         offset++;
 564         cwd[len++] = '/';
 565         cwd[len] = 0;
 566         return cwd + offset;
 567 }
 568
 569 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 570 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 571 {
 572         int root_len;
 573
 574         if (check_repository_format_gently(".", nongit_ok))
 575                 return NULL;
 576
 577         /* --work-tree is set without --git-dir; use discovered one */
 578         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 579                 const char *gitdir;
 580
 581                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 582                 if (chdir(cwd))
 583                         die_errno("Could not come back to cwd");
 584                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 585         }
 586
 587         inside_git_dir = 1;
 588         inside_work_tree = 0;
 589         if (offset != len) {
 590                 if (chdir(cwd))
 591                         die_errno("Cannot come back to cwd");
 592                 root_len = offset_1st_component(cwd);
 593                 cwd[offset > root_len ? offset : root_len] = '\0';
 594                 set_git_dir(cwd);
 595         }
 596         else
 597                 set_git_dir(".");
 598         return NULL;
 599 }
 600
 601 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 602 {
 603         if (!nongit_ok)
 604                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 605         if (chdir(cwd))
 606                 die_errno("Cannot come back to cwd");
 607         *nongit_ok = 1;
 608         return NULL;
 609 }
 610
 611 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 612 {
 613         struct stat buf;
 614         if (stat(path, &buf)) {
 615                 die_errno("failed to stat '%*s%s%s'",
 616                                 prefix_len,
 617                                 prefix ? prefix : "",
 618                                 prefix ? "/" : "", path);
 619         }
 620         return buf.st_dev;
 621 }
 622
 623 /*
 624  * We cannot decide in this function whether we are in the work tree or
 625  * not, since the config can only be read _after_ this function was called.
 626  */
 627 static const char *setup_git_directory_gently_1(int *nongit_ok)
 628 {
 629         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 630         static char cwd[PATH_MAX+1];
 631         const char *gitdirenv, *ret;
 632         char *gitfile;
 633         int len, offset, offset_parent, ceil_offset;
 634         dev_t current_device = 0;
 635         int one_filesystem = 1;
 636
 637         /*
 638          * Let's assume that we are in a git repository.
 639          * If it turns out later that we are somewhere else, the value will be
 640          * updated accordingly.
 641          */
 642         if (nongit_ok)
 643                 *nongit_ok = 0;
 644
 645         if (!getcwd(cwd, sizeof(cwd)-1))
 646                 die_errno("Unable to read current working directory");
 647         offset = len = strlen(cwd);
 648
 649         /*
 650          * If GIT_DIR is set explicitly, we're not going
 651          * to do any discovery, but we still do repository
 652          * validation.
 653          */
 654         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 655         if (gitdirenv)
 656                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 657
 658         ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
 659         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 660                 ceil_offset = 1;
 661
 662         /*
 663          * Test in the following order (relative to the cwd):
 664          * - .git (file containing "gitdir: <path>")
 665          * - .git/
 666          * - ./ (bare)
 667          * - ../.git
 668          * - ../.git/
 669          * - ../ (bare)
 670          * - ../../.git/
 671          *   etc.
 672          */
 673         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 674         if (one_filesystem)
 675                 current_device = get_device_or_die(".", NULL, 0);
 676         for (;;) {
 677                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 678                 if (gitfile)
 679                         gitdirenv = gitfile = xstrdup(gitfile);
 680                 else {
 681                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 682                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 683                 }
 684
 685                 if (gitdirenv) {
 686                         ret = setup_discovered_git_dir(gitdirenv,
 687                                                        cwd, offset, len,
 688                                                        nongit_ok);
 689                         free(gitfile);
 690                         return ret;
 691                 }
 692                 free(gitfile);
 693
 694                 if (is_git_directory("."))
 695                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 696
 697                 offset_parent = offset;
 698                 while (--offset_parent > ceil_offset && cwd[offset_parent] != '/');
 699                 if (offset_parent <= ceil_offset)
 700                         return setup_nongit(cwd, nongit_ok);
 701                 if (one_filesystem) {
 702                         dev_t parent_device = get_device_or_die("..", cwd, offset);
 703                         if (parent_device != current_device) {
 704                                 if (nongit_ok) {
 705                                         if (chdir(cwd))
 706                                                 die_errno("Cannot come back to cwd");
 707                                         *nongit_ok = 1;
 708                                         return NULL;
 709                                 }
 710                                 cwd[offset] = '\0';
 711                                 die("Not a git repository (or any parent up to mount point %s)\n"
 712                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 713                         }
 714                 }
 715                 if (chdir("..")) {
 716                         cwd[offset] = '\0';
 717                         die_errno("Cannot change to '%s/..'", cwd);
 718                 }
 719                 offset = offset_parent;
 720         }
 721 }
 722
 723 const char *setup_git_directory_gently(int *nongit_ok)
 724 {
 725         const char *prefix;
 726
 727         prefix = setup_git_directory_gently_1(nongit_ok);
 728         if (prefix)
 729                 setenv("GIT_PREFIX", prefix, 1);
 730         else
 731                 setenv("GIT_PREFIX", "", 1);
 732
 733         if (startup_info) {
 734                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 735                 startup_info->prefix = prefix;
 736         }
 737         return prefix;
 738 }
 739
 740 int git_config_perm(const char *var, const char *value)
 741 {
 742         int i;
 743         char *endptr;
 744
 745         if (value == NULL)
 746                 return PERM_GROUP;
 747
 748         if (!strcmp(value, "umask"))
 749                 return PERM_UMASK;
 750         if (!strcmp(value, "group"))
 751                 return PERM_GROUP;
 752         if (!strcmp(value, "all") ||
 753             !strcmp(value, "world") ||
 754             !strcmp(value, "everybody"))
 755                 return PERM_EVERYBODY;
 756
 757         /* Parse octal numbers */
 758         i = strtol(value, &endptr, 8);
 759
 760         /* If not an octal number, maybe true/false? */
 761         if (*endptr != 0)
 762                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 763
 764         /*
 765          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 766          * a chmod value to restrict to.
 767          */
 768         switch (i) {
 769         case PERM_UMASK:               /* 0 */
 770                 return PERM_UMASK;
 771         case OLD_PERM_GROUP:           /* 1 */
 772                 return PERM_GROUP;
 773         case OLD_PERM_EVERYBODY:       /* 2 */
 774                 return PERM_EVERYBODY;
 775         }
 776
 777         /* A filemode value was given: 0xxx */
 778
 779         if ((i & 0600) != 0600)
 780                 die("Problem with core.sharedRepository filemode value "
 781                     "(0%.3o).\nThe owner of files must always have "
 782                     "read and write permissions.", i);
 783
 784         /*
 785          * Mask filemode value. Others can not get write permission.
 786          * x flags for directories are handled separately.
 787          */
 788         return -(i & 0666);
 789 }
 790
 791 int check_repository_format_version(const char *var, const char *value, void *cb)
 792 {
 793         if (strcmp(var, "core.repositoryformatversion") == 0)
 794                 repository_format_version = git_config_int(var, value);
 795         else if (strcmp(var, "core.sharedrepository") == 0)
 796                 shared_repository = git_config_perm(var, value);
 797         else if (strcmp(var, "core.bare") == 0) {
 798                 is_bare_repository_cfg = git_config_bool(var, value);
 799                 if (is_bare_repository_cfg == 1)
 800                         inside_work_tree = -1;
 801         } else if (strcmp(var, "core.worktree") == 0) {
 802                 if (!value)
 803                         return config_error_nonbool(var);
 804                 free(git_work_tree_cfg);
 805                 git_work_tree_cfg = xstrdup(value);
 806                 inside_work_tree = -1;
 807         }
 808         return 0;
 809 }
 810
 811 int check_repository_format(void)
 812 {
 813         return check_repository_format_gently(get_git_dir(), NULL);
 814 }
 815
 816 /*
 817  * Returns the "prefix", a path to the current working directory
 818  * relative to the work tree root, or NULL, if the current working
 819  * directory is not a strict subdirectory of the work tree root. The
 820  * prefix always ends with a '/' character.
 821  */
 822 const char *setup_git_directory(void)
 823 {
 824         return setup_git_directory_gently(NULL);
 825 }
 826
 827 const char *resolve_gitdir(const char *suspect)
 828 {
 829         if (is_git_directory(suspect))
 830                 return suspect;
 831         return read_gitfile(suspect);
 832 }