setup.c

   1 #include "cache.h"
   2 #include "dir.h"
   3 #include "string-list.h"
   4
   5 static int inside_git_dir = -1;
   6 static int inside_work_tree = -1;
   7
   8 /*
   9  * Normalize "path", prepending the "prefix" for relative paths. If
  10  * remaining_prefix is not NULL, return the actual prefix still
  11  * remains in the path. For example, prefix = sub1/sub2/ and path is
  12  *
  13  *  foo          -> sub1/sub2/foo  (full prefix)
  14  *  ../foo       -> sub1/foo       (remaining prefix is sub1/)
  15  *  ../../bar    -> bar            (no remaining prefix)
  16  *  ../../sub1/sub2/foo -> sub1/sub2/foo (but no remaining prefix)
  17  *  `pwd`/../bar -> sub1/bar       (no remaining prefix)
  18  */
  19 char *prefix_path_gently(const char *prefix, int len,
  20                          int *remaining_prefix, const char *path)
  21 {
  22         const char *orig = path;
  23         char *sanitized;
  24         if (is_absolute_path(orig)) {
  25                 const char *temp = real_path(path);
  26                 sanitized = xmalloc(len + strlen(temp) + 1);
  27                 strcpy(sanitized, temp);
  28                 if (remaining_prefix)
  29                         *remaining_prefix = 0;
  30         } else {
  31                 sanitized = xmalloc(len + strlen(path) + 1);
  32                 if (len)
  33                         memcpy(sanitized, prefix, len);
  34                 strcpy(sanitized + len, path);
  35                 if (remaining_prefix)
  36                         *remaining_prefix = len;
  37         }
  38         if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix))
  39                 goto error_out;
  40         if (is_absolute_path(orig)) {
  41                 size_t root_len, len, total;
  42                 const char *work_tree = get_git_work_tree();
  43                 if (!work_tree)
  44                         goto error_out;
  45                 len = strlen(work_tree);
  46                 root_len = offset_1st_component(work_tree);
  47                 total = strlen(sanitized) + 1;
  48                 if (strncmp(sanitized, work_tree, len) ||
  49                     (len > root_len && sanitized[len] != '\0' && sanitized[len] != '/')) {
  50                 error_out:
  51                         free(sanitized);
  52                         return NULL;
  53                 }
  54                 if (sanitized[len] == '/')
  55                         len++;
  56                 memmove(sanitized, sanitized + len, total - len);
  57         }
  58         return sanitized;
  59 }
  60
  61 char *prefix_path(const char *prefix, int len, const char *path)
  62 {
  63         char *r = prefix_path_gently(prefix, len, NULL, path);
  64         if (!r)
  65                 die("'%s' is outside repository", path);
  66         return r;
  67 }
  68
  69 int path_inside_repo(const char *prefix, const char *path)
  70 {
  71         int len = prefix ? strlen(prefix) : 0;
  72         char *r = prefix_path_gently(prefix, len, NULL, path);
  73         if (r) {
  74                 free(r);
  75                 return 1;
  76         }
  77         return 0;
  78 }
  79
  80 int check_filename(const char *prefix, const char *arg)
  81 {
  82         const char *name;
  83         struct stat st;
  84
  85         if (!prefixcmp(arg, ":/")) {
  86                 if (arg[2] == '\0') /* ":/" is root dir, always exists */
  87                         return 1;
  88                 name = arg + 2;
  89         } else if (prefix)
  90                 name = prefix_filename(prefix, strlen(prefix), arg);
  91         else
  92                 name = arg;
  93         if (!lstat(name, &st))
  94                 return 1; /* file exists */
  95         if (errno == ENOENT || errno == ENOTDIR)
  96                 return 0; /* file does not exist */
  97         die_errno("failed to stat '%s'", arg);
  98 }
  99
 100 static void NORETURN die_verify_filename(const char *prefix,
 101                                          const char *arg,
 102                                          int diagnose_misspelt_rev)
 103 {
 104         if (!diagnose_misspelt_rev)
 105                 die("%s: no such path in the working tree.\n"
 106                     "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
 107                     arg);
 108         /*
 109          * Saying "'(icase)foo' does not exist in the index" when the
 110          * user gave us ":(icase)foo" is just stupid.  A magic pathspec
 111          * begins with a colon and is followed by a non-alnum; do not
 112          * let maybe_die_on_misspelt_object_name() even trigger.
 113          */
 114         if (!(arg[0] == ':' && !isalnum(arg[1])))
 115                 maybe_die_on_misspelt_object_name(arg, prefix);
 116
 117         /* ... or fall back the most general message. */
 118         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 119             "Use '--' to separate paths from revisions, like this:\n"
 120             "'git <command> [<revision>...] -- [<file>...]'", arg);
 121
 122 }
 123
 124 /*
 125  * Verify a filename that we got as an argument for a pathspec
 126  * entry. Note that a filename that begins with "-" never verifies
 127  * as true, because even if such a filename were to exist, we want
 128  * it to be preceded by the "--" marker (or we want the user to
 129  * use a format like "./-filename")
 130  *
 131  * The "diagnose_misspelt_rev" is used to provide a user-friendly
 132  * diagnosis when dying upon finding that "name" is not a pathname.
 133  * If set to 1, the diagnosis will try to diagnose "name" as an
 134  * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 135  * will only complain about an inexisting file.
 136  *
 137  * This function is typically called to check that a "file or rev"
 138  * argument is unambiguous. In this case, the caller will want
 139  * diagnose_misspelt_rev == 1 when verifying the first non-rev
 140  * argument (which could have been a revision), and
 141  * diagnose_misspelt_rev == 0 for the next ones (because we already
 142  * saw a filename, there's not ambiguity anymore).
 143  */
 144 void verify_filename(const char *prefix,
 145                      const char *arg,
 146                      int diagnose_misspelt_rev)
 147 {
 148         if (*arg == '-')
 149                 die("bad flag '%s' used after filename", arg);
 150         if (check_filename(prefix, arg))
 151                 return;
 152         die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 153 }
 154
 155 /*
 156  * Opposite of the above: the command line did not have -- marker
 157  * and we parsed the arg as a refname.  It should not be interpretable
 158  * as a filename.
 159  */
 160 void verify_non_filename(const char *prefix, const char *arg)
 161 {
 162         if (!is_inside_work_tree() || is_inside_git_dir())
 163                 return;
 164         if (*arg == '-')
 165                 return; /* flag */
 166         if (!check_filename(prefix, arg))
 167                 return;
 168         die("ambiguous argument '%s': both revision and filename\n"
 169             "Use '--' to separate paths from revisions, like this:\n"
 170             "'git <command> [<revision>...] -- [<file>...]'", arg);
 171 }
 172
 173
 174 /*
 175  * Test if it looks like we're at a git directory.
 176  * We want to see:
 177  *
 178  *  - either an objects/ directory _or_ the proper
 179  *    GIT_OBJECT_DIRECTORY environment variable
 180  *  - a refs/ directory
 181  *  - either a HEAD symlink or a HEAD file that is formatted as
 182  *    a proper "ref:", or a regular file HEAD that has a properly
 183  *    formatted sha1 object name.
 184  */
 185 int is_git_directory(const char *suspect)
 186 {
 187         char path[PATH_MAX];
 188         size_t len = strlen(suspect);
 189
 190         if (PATH_MAX <= len + strlen("/objects"))
 191                 die("Too long path: %.*s", 60, suspect);
 192         strcpy(path, suspect);
 193         if (getenv(DB_ENVIRONMENT)) {
 194                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 195                         return 0;
 196         }
 197         else {
 198                 strcpy(path + len, "/objects");
 199                 if (access(path, X_OK))
 200                         return 0;
 201         }
 202
 203         strcpy(path + len, "/refs");
 204         if (access(path, X_OK))
 205                 return 0;
 206
 207         strcpy(path + len, "/HEAD");
 208         if (validate_headref(path))
 209                 return 0;
 210
 211         return 1;
 212 }
 213
 214 int is_inside_git_dir(void)
 215 {
 216         if (inside_git_dir < 0)
 217                 inside_git_dir = is_inside_dir(get_git_dir());
 218         return inside_git_dir;
 219 }
 220
 221 int is_inside_work_tree(void)
 222 {
 223         if (inside_work_tree < 0)
 224                 inside_work_tree = is_inside_dir(get_git_work_tree());
 225         return inside_work_tree;
 226 }
 227
 228 void setup_work_tree(void)
 229 {
 230         struct strbuf sb = STRBUF_INIT;
 231         const char *work_tree, *git_dir;
 232         static int initialized = 0;
 233
 234         if (initialized)
 235                 return;
 236         work_tree = get_git_work_tree();
 237         git_dir = get_git_dir();
 238         if (!is_absolute_path(git_dir))
 239                 git_dir = real_path(get_git_dir());
 240         if (!work_tree || chdir(work_tree))
 241                 die("This operation must be run in a work tree");
 242
 243         /*
 244          * Make sure subsequent git processes find correct worktree
 245          * if $GIT_WORK_TREE is set relative
 246          */
 247         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 248                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 249
 250         set_git_dir(relative_path(git_dir, work_tree, &sb));
 251         initialized = 1;
 252
 253         strbuf_release(&sb);
 254 }
 255
 256 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 257 {
 258         char repo_config[PATH_MAX+1];
 259
 260         /*
 261          * git_config() can't be used here because it calls git_pathdup()
 262          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 263          * set git_dir to ".git".
 264          *
 265          * We are in gitdir setup, no git dir has been found useable yet.
 266          * Use a gentler version of git_config() to check if this repo
 267          * is a good one.
 268          */
 269         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 270         git_config_early(check_repository_format_version, NULL, repo_config);
 271         if (GIT_REPO_VERSION < repository_format_version) {
 272                 if (!nongit_ok)
 273                         die ("Expected git repo version <= %d, found %d",
 274                              GIT_REPO_VERSION, repository_format_version);
 275                 warning("Expected git repo version <= %d, found %d",
 276                         GIT_REPO_VERSION, repository_format_version);
 277                 warning("Please upgrade Git");
 278                 *nongit_ok = -1;
 279                 return -1;
 280         }
 281         return 0;
 282 }
 283
 284 /*
 285  * Try to read the location of the git directory from the .git file,
 286  * return path to git directory if found.
 287  */
 288 const char *read_gitfile(const char *path)
 289 {
 290         char *buf;
 291         char *dir;
 292         const char *slash;
 293         struct stat st;
 294         int fd;
 295         ssize_t len;
 296
 297         if (stat(path, &st))
 298                 return NULL;
 299         if (!S_ISREG(st.st_mode))
 300                 return NULL;
 301         fd = open(path, O_RDONLY);
 302         if (fd < 0)
 303                 die_errno("Error opening '%s'", path);
 304         buf = xmalloc(st.st_size + 1);
 305         len = read_in_full(fd, buf, st.st_size);
 306         close(fd);
 307         if (len != st.st_size)
 308                 die("Error reading %s", path);
 309         buf[len] = '\0';
 310         if (prefixcmp(buf, "gitdir: "))
 311                 die("Invalid gitfile format: %s", path);
 312         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 313                 len--;
 314         if (len < 9)
 315                 die("No path in gitfile: %s", path);
 316         buf[len] = '\0';
 317         dir = buf + 8;
 318
 319         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 320                 size_t pathlen = slash+1 - path;
 321                 size_t dirlen = pathlen + len - 8;
 322                 dir = xmalloc(dirlen + 1);
 323                 strncpy(dir, path, pathlen);
 324                 strncpy(dir + pathlen, buf + 8, len - 8);
 325                 dir[dirlen] = '\0';
 326                 free(buf);
 327                 buf = dir;
 328         }
 329
 330         if (!is_git_directory(dir))
 331                 die("Not a git repository: %s", dir);
 332         path = real_path(dir);
 333
 334         free(buf);
 335         return path;
 336 }
 337
 338 static const char *setup_explicit_git_dir(const char *gitdirenv,
 339                                           char *cwd, int len,
 340                                           int *nongit_ok)
 341 {
 342         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 343         const char *worktree;
 344         char *gitfile;
 345         int offset;
 346
 347         if (PATH_MAX - 40 < strlen(gitdirenv))
 348                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 349
 350         gitfile = (char*)read_gitfile(gitdirenv);
 351         if (gitfile) {
 352                 gitfile = xstrdup(gitfile);
 353                 gitdirenv = gitfile;
 354         }
 355
 356         if (!is_git_directory(gitdirenv)) {
 357                 if (nongit_ok) {
 358                         *nongit_ok = 1;
 359                         free(gitfile);
 360                         return NULL;
 361                 }
 362                 die("Not a git repository: '%s'", gitdirenv);
 363         }
 364
 365         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 366                 free(gitfile);
 367                 return NULL;
 368         }
 369
 370         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 371         if (work_tree_env)
 372                 set_git_work_tree(work_tree_env);
 373         else if (is_bare_repository_cfg > 0) {
 374                 if (git_work_tree_cfg) /* #22.2, #30 */
 375                         die("core.bare and core.worktree do not make sense");
 376
 377                 /* #18, #26 */
 378                 set_git_dir(gitdirenv);
 379                 free(gitfile);
 380                 return NULL;
 381         }
 382         else if (git_work_tree_cfg) { /* #6, #14 */
 383                 if (is_absolute_path(git_work_tree_cfg))
 384                         set_git_work_tree(git_work_tree_cfg);
 385                 else {
 386                         char core_worktree[PATH_MAX];
 387                         if (chdir(gitdirenv))
 388                                 die_errno("Could not chdir to '%s'", gitdirenv);
 389                         if (chdir(git_work_tree_cfg))
 390                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 391                         if (!getcwd(core_worktree, PATH_MAX))
 392                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 393                         if (chdir(cwd))
 394                                 die_errno("Could not come back to cwd");
 395                         set_git_work_tree(core_worktree);
 396                 }
 397         }
 398         else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 399                 /* #16d */
 400                 set_git_dir(gitdirenv);
 401                 free(gitfile);
 402                 return NULL;
 403         }
 404         else /* #2, #10 */
 405                 set_git_work_tree(".");
 406
 407         /* set_git_work_tree() must have been called by now */
 408         worktree = get_git_work_tree();
 409
 410         /* both get_git_work_tree() and cwd are already normalized */
 411         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 412                 set_git_dir(gitdirenv);
 413                 free(gitfile);
 414                 return NULL;
 415         }
 416
 417         offset = dir_inside_of(cwd, worktree);
 418         if (offset >= 0) {      /* cwd inside worktree? */
 419                 set_git_dir(real_path(gitdirenv));
 420                 if (chdir(worktree))
 421                         die_errno("Could not chdir to '%s'", worktree);
 422                 cwd[len++] = '/';
 423                 cwd[len] = '\0';
 424                 free(gitfile);
 425                 return cwd + offset;
 426         }
 427
 428         /* cwd outside worktree */
 429         set_git_dir(gitdirenv);
 430         free(gitfile);
 431         return NULL;
 432 }
 433
 434 static const char *setup_discovered_git_dir(const char *gitdir,
 435                                             char *cwd, int offset, int len,
 436                                             int *nongit_ok)
 437 {
 438         if (check_repository_format_gently(gitdir, nongit_ok))
 439                 return NULL;
 440
 441         /* --work-tree is set without --git-dir; use discovered one */
 442         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 443                 if (offset != len && !is_absolute_path(gitdir))
 444                         gitdir = xstrdup(real_path(gitdir));
 445                 if (chdir(cwd))
 446                         die_errno("Could not come back to cwd");
 447                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 448         }
 449
 450         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 451         if (is_bare_repository_cfg > 0) {
 452                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 453                 if (chdir(cwd))
 454                         die_errno("Could not come back to cwd");
 455                 return NULL;
 456         }
 457
 458         /* #0, #1, #5, #8, #9, #12, #13 */
 459         set_git_work_tree(".");
 460         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 461                 set_git_dir(gitdir);
 462         inside_git_dir = 0;
 463         inside_work_tree = 1;
 464         if (offset == len)
 465                 return NULL;
 466
 467         /* Make "offset" point to past the '/', and add a '/' at the end */
 468         offset++;
 469         cwd[len++] = '/';
 470         cwd[len] = 0;
 471         return cwd + offset;
 472 }
 473
 474 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 475 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 476 {
 477         int root_len;
 478
 479         if (check_repository_format_gently(".", nongit_ok))
 480                 return NULL;
 481
 482         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 483
 484         /* --work-tree is set without --git-dir; use discovered one */
 485         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 486                 const char *gitdir;
 487
 488                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 489                 if (chdir(cwd))
 490                         die_errno("Could not come back to cwd");
 491                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 492         }
 493
 494         inside_git_dir = 1;
 495         inside_work_tree = 0;
 496         if (offset != len) {
 497                 if (chdir(cwd))
 498                         die_errno("Cannot come back to cwd");
 499                 root_len = offset_1st_component(cwd);
 500                 cwd[offset > root_len ? offset : root_len] = '\0';
 501                 set_git_dir(cwd);
 502         }
 503         else
 504                 set_git_dir(".");
 505         return NULL;
 506 }
 507
 508 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 509 {
 510         if (!nongit_ok)
 511                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 512         if (chdir(cwd))
 513                 die_errno("Cannot come back to cwd");
 514         *nongit_ok = 1;
 515         return NULL;
 516 }
 517
 518 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 519 {
 520         struct stat buf;
 521         if (stat(path, &buf)) {
 522                 die_errno("failed to stat '%*s%s%s'",
 523                                 prefix_len,
 524                                 prefix ? prefix : "",
 525                                 prefix ? "/" : "", path);
 526         }
 527         return buf.st_dev;
 528 }
 529
 530 /*
 531  * A "string_list_each_func_t" function that canonicalizes an entry
 532  * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 533  * discards it if unusable.  The presence of an empty entry in
 534  * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 535  * subsequent entries.
 536  */
 537 static int canonicalize_ceiling_entry(struct string_list_item *item,
 538                                       void *cb_data)
 539 {
 540         int *empty_entry_found = cb_data;
 541         char *ceil = item->string;
 542
 543         if (!*ceil) {
 544                 *empty_entry_found = 1;
 545                 return 0;
 546         } else if (!is_absolute_path(ceil)) {
 547                 return 0;
 548         } else if (*empty_entry_found) {
 549                 /* Keep entry but do not canonicalize it */
 550                 return 1;
 551         } else {
 552                 const char *real_path = real_path_if_valid(ceil);
 553                 if (!real_path)
 554                         return 0;
 555                 free(item->string);
 556                 item->string = xstrdup(real_path);
 557                 return 1;
 558         }
 559 }
 560
 561 /*
 562  * We cannot decide in this function whether we are in the work tree or
 563  * not, since the config can only be read _after_ this function was called.
 564  */
 565 static const char *setup_git_directory_gently_1(int *nongit_ok)
 566 {
 567         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 568         struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 569         static char cwd[PATH_MAX+1];
 570         const char *gitdirenv, *ret;
 571         char *gitfile;
 572         int len, offset, offset_parent, ceil_offset = -1;
 573         dev_t current_device = 0;
 574         int one_filesystem = 1;
 575
 576         /*
 577          * Let's assume that we are in a git repository.
 578          * If it turns out later that we are somewhere else, the value will be
 579          * updated accordingly.
 580          */
 581         if (nongit_ok)
 582                 *nongit_ok = 0;
 583
 584         if (!getcwd(cwd, sizeof(cwd)-1))
 585                 die_errno("Unable to read current working directory");
 586         offset = len = strlen(cwd);
 587
 588         /*
 589          * If GIT_DIR is set explicitly, we're not going
 590          * to do any discovery, but we still do repository
 591          * validation.
 592          */
 593         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 594         if (gitdirenv)
 595                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 596
 597         if (env_ceiling_dirs) {
 598                 int empty_entry_found = 0;
 599
 600                 string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 601                 filter_string_list(&ceiling_dirs, 0,
 602                                    canonicalize_ceiling_entry, &empty_entry_found);
 603                 ceil_offset = longest_ancestor_length(cwd, &ceiling_dirs);
 604                 string_list_clear(&ceiling_dirs, 0);
 605         }
 606
 607         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 608                 ceil_offset = 1;
 609
 610         /*
 611          * Test in the following order (relative to the cwd):
 612          * - .git (file containing "gitdir: <path>")
 613          * - .git/
 614          * - ./ (bare)
 615          * - ../.git
 616          * - ../.git/
 617          * - ../ (bare)
 618          * - ../../.git/
 619          *   etc.
 620          */
 621         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 622         if (one_filesystem)
 623                 current_device = get_device_or_die(".", NULL, 0);
 624         for (;;) {
 625                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 626                 if (gitfile)
 627                         gitdirenv = gitfile = xstrdup(gitfile);
 628                 else {
 629                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 630                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 631                 }
 632
 633                 if (gitdirenv) {
 634                         ret = setup_discovered_git_dir(gitdirenv,
 635                                                        cwd, offset, len,
 636                                                        nongit_ok);
 637                         free(gitfile);
 638                         return ret;
 639                 }
 640                 free(gitfile);
 641
 642                 if (is_git_directory("."))
 643                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 644
 645                 offset_parent = offset;
 646                 while (--offset_parent > ceil_offset && cwd[offset_parent] != '/');
 647                 if (offset_parent <= ceil_offset)
 648                         return setup_nongit(cwd, nongit_ok);
 649                 if (one_filesystem) {
 650                         dev_t parent_device = get_device_or_die("..", cwd, offset);
 651                         if (parent_device != current_device) {
 652                                 if (nongit_ok) {
 653                                         if (chdir(cwd))
 654                                                 die_errno("Cannot come back to cwd");
 655                                         *nongit_ok = 1;
 656                                         return NULL;
 657                                 }
 658                                 cwd[offset] = '\0';
 659                                 die("Not a git repository (or any parent up to mount point %s)\n"
 660                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 661                         }
 662                 }
 663                 if (chdir("..")) {
 664                         cwd[offset] = '\0';
 665                         die_errno("Cannot change to '%s/..'", cwd);
 666                 }
 667                 offset = offset_parent;
 668         }
 669 }
 670
 671 const char *setup_git_directory_gently(int *nongit_ok)
 672 {
 673         const char *prefix;
 674
 675         prefix = setup_git_directory_gently_1(nongit_ok);
 676         if (prefix)
 677                 setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 678         else
 679                 setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 680
 681         if (startup_info) {
 682                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 683                 startup_info->prefix = prefix;
 684         }
 685         return prefix;
 686 }
 687
 688 int git_config_perm(const char *var, const char *value)
 689 {
 690         int i;
 691         char *endptr;
 692
 693         if (value == NULL)
 694                 return PERM_GROUP;
 695
 696         if (!strcmp(value, "umask"))
 697                 return PERM_UMASK;
 698         if (!strcmp(value, "group"))
 699                 return PERM_GROUP;
 700         if (!strcmp(value, "all") ||
 701             !strcmp(value, "world") ||
 702             !strcmp(value, "everybody"))
 703                 return PERM_EVERYBODY;
 704
 705         /* Parse octal numbers */
 706         i = strtol(value, &endptr, 8);
 707
 708         /* If not an octal number, maybe true/false? */
 709         if (*endptr != 0)
 710                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 711
 712         /*
 713          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 714          * a chmod value to restrict to.
 715          */
 716         switch (i) {
 717         case PERM_UMASK:               /* 0 */
 718                 return PERM_UMASK;
 719         case OLD_PERM_GROUP:           /* 1 */
 720                 return PERM_GROUP;
 721         case OLD_PERM_EVERYBODY:       /* 2 */
 722                 return PERM_EVERYBODY;
 723         }
 724
 725         /* A filemode value was given: 0xxx */
 726
 727         if ((i & 0600) != 0600)
 728                 die("Problem with core.sharedRepository filemode value "
 729                     "(0%.3o).\nThe owner of files must always have "
 730                     "read and write permissions.", i);
 731
 732         /*
 733          * Mask filemode value. Others can not get write permission.
 734          * x flags for directories are handled separately.
 735          */
 736         return -(i & 0666);
 737 }
 738
 739 int check_repository_format_version(const char *var, const char *value, void *cb)
 740 {
 741         if (strcmp(var, "core.repositoryformatversion") == 0)
 742                 repository_format_version = git_config_int(var, value);
 743         else if (strcmp(var, "core.sharedrepository") == 0)
 744                 shared_repository = git_config_perm(var, value);
 745         else if (strcmp(var, "core.bare") == 0) {
 746                 is_bare_repository_cfg = git_config_bool(var, value);
 747                 if (is_bare_repository_cfg == 1)
 748                         inside_work_tree = -1;
 749         } else if (strcmp(var, "core.worktree") == 0) {
 750                 if (!value)
 751                         return config_error_nonbool(var);
 752                 free(git_work_tree_cfg);
 753                 git_work_tree_cfg = xstrdup(value);
 754                 inside_work_tree = -1;
 755         }
 756         return 0;
 757 }
 758
 759 int check_repository_format(void)
 760 {
 761         return check_repository_format_gently(get_git_dir(), NULL);
 762 }
 763
 764 /*
 765  * Returns the "prefix", a path to the current working directory
 766  * relative to the work tree root, or NULL, if the current working
 767  * directory is not a strict subdirectory of the work tree root. The
 768  * prefix always ends with a '/' character.
 769  */
 770 const char *setup_git_directory(void)
 771 {
 772         return setup_git_directory_gently(NULL);
 773 }
 774
 775 const char *resolve_gitdir(const char *suspect)
 776 {
 777         if (is_git_directory(suspect))
 778                 return suspect;
 779         return read_gitfile(suspect);
 780 }
 781
 782 /* if any standard file descriptor is missing open it to /dev/null */
 783 void sanitize_stdfds(void)
 784 {
 785         int fd = open("/dev/null", O_RDWR, 0);
 786         while (fd != -1 && fd < 2)
 787                 fd = dup(fd);
 788         if (fd == -1)
 789                 die_errno("open /dev/null or dup failed");
 790         if (fd > 2)
 791                 close(fd);
 792 }