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 (starts_with(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         const char *work_tree, *git_dir;
 231         static int initialized = 0;
 232
 233         if (initialized)
 234                 return;
 235         work_tree = get_git_work_tree();
 236         git_dir = get_git_dir();
 237         if (!is_absolute_path(git_dir))
 238                 git_dir = real_path(get_git_dir());
 239         if (!work_tree || chdir(work_tree))
 240                 die("This operation must be run in a work tree");
 241
 242         /*
 243          * Make sure subsequent git processes find correct worktree
 244          * if $GIT_WORK_TREE is set relative
 245          */
 246         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 247                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 248
 249         set_git_dir(remove_leading_path(git_dir, work_tree));
 250         initialized = 1;
 251 }
 252
 253 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 254 {
 255         char repo_config[PATH_MAX+1];
 256
 257         /*
 258          * git_config() can't be used here because it calls git_pathdup()
 259          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 260          * set git_dir to ".git".
 261          *
 262          * We are in gitdir setup, no git dir has been found useable yet.
 263          * Use a gentler version of git_config() to check if this repo
 264          * is a good one.
 265          */
 266         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 267         git_config_early(check_repository_format_version, NULL, repo_config);
 268         if (GIT_REPO_VERSION < repository_format_version) {
 269                 if (!nongit_ok)
 270                         die ("Expected git repo version <= %d, found %d",
 271                              GIT_REPO_VERSION, repository_format_version);
 272                 warning("Expected git repo version <= %d, found %d",
 273                         GIT_REPO_VERSION, repository_format_version);
 274                 warning("Please upgrade Git");
 275                 *nongit_ok = -1;
 276                 return -1;
 277         }
 278         return 0;
 279 }
 280
 281 /*
 282  * Try to read the location of the git directory from the .git file,
 283  * return path to git directory if found.
 284  */
 285 const char *read_gitfile(const char *path)
 286 {
 287         char *buf;
 288         char *dir;
 289         const char *slash;
 290         struct stat st;
 291         int fd;
 292         ssize_t len;
 293
 294         if (stat(path, &st))
 295                 return NULL;
 296         if (!S_ISREG(st.st_mode))
 297                 return NULL;
 298         fd = open(path, O_RDONLY);
 299         if (fd < 0)
 300                 die_errno("Error opening '%s'", path);
 301         buf = xmalloc(st.st_size + 1);
 302         len = read_in_full(fd, buf, st.st_size);
 303         close(fd);
 304         if (len != st.st_size)
 305                 die("Error reading %s", path);
 306         buf[len] = '\0';
 307         if (!starts_with(buf, "gitdir: "))
 308                 die("Invalid gitfile format: %s", path);
 309         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 310                 len--;
 311         if (len < 9)
 312                 die("No path in gitfile: %s", path);
 313         buf[len] = '\0';
 314         dir = buf + 8;
 315
 316         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 317                 size_t pathlen = slash+1 - path;
 318                 size_t dirlen = pathlen + len - 8;
 319                 dir = xmalloc(dirlen + 1);
 320                 strncpy(dir, path, pathlen);
 321                 strncpy(dir + pathlen, buf + 8, len - 8);
 322                 dir[dirlen] = '\0';
 323                 free(buf);
 324                 buf = dir;
 325         }
 326
 327         if (!is_git_directory(dir))
 328                 die("Not a git repository: %s", dir);
 329         path = real_path(dir);
 330
 331         free(buf);
 332         return path;
 333 }
 334
 335 static const char *setup_explicit_git_dir(const char *gitdirenv,
 336                                           char *cwd, int len,
 337                                           int *nongit_ok)
 338 {
 339         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 340         const char *worktree;
 341         char *gitfile;
 342         int offset;
 343
 344         if (PATH_MAX - 40 < strlen(gitdirenv))
 345                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 346
 347         gitfile = (char*)read_gitfile(gitdirenv);
 348         if (gitfile) {
 349                 gitfile = xstrdup(gitfile);
 350                 gitdirenv = gitfile;
 351         }
 352
 353         if (!is_git_directory(gitdirenv)) {
 354                 if (nongit_ok) {
 355                         *nongit_ok = 1;
 356                         free(gitfile);
 357                         return NULL;
 358                 }
 359                 die("Not a git repository: '%s'", gitdirenv);
 360         }
 361
 362         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 363                 free(gitfile);
 364                 return NULL;
 365         }
 366
 367         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 368         if (work_tree_env)
 369                 set_git_work_tree(work_tree_env);
 370         else if (is_bare_repository_cfg > 0) {
 371                 if (git_work_tree_cfg) /* #22.2, #30 */
 372                         die("core.bare and core.worktree do not make sense");
 373
 374                 /* #18, #26 */
 375                 set_git_dir(gitdirenv);
 376                 free(gitfile);
 377                 return NULL;
 378         }
 379         else if (git_work_tree_cfg) { /* #6, #14 */
 380                 if (is_absolute_path(git_work_tree_cfg))
 381                         set_git_work_tree(git_work_tree_cfg);
 382                 else {
 383                         char core_worktree[PATH_MAX];
 384                         if (chdir(gitdirenv))
 385                                 die_errno("Could not chdir to '%s'", gitdirenv);
 386                         if (chdir(git_work_tree_cfg))
 387                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 388                         if (!getcwd(core_worktree, PATH_MAX))
 389                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 390                         if (chdir(cwd))
 391                                 die_errno("Could not come back to cwd");
 392                         set_git_work_tree(core_worktree);
 393                 }
 394         }
 395         else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 396                 /* #16d */
 397                 set_git_dir(gitdirenv);
 398                 free(gitfile);
 399                 return NULL;
 400         }
 401         else /* #2, #10 */
 402                 set_git_work_tree(".");
 403
 404         /* set_git_work_tree() must have been called by now */
 405         worktree = get_git_work_tree();
 406
 407         /* both get_git_work_tree() and cwd are already normalized */
 408         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 409                 set_git_dir(gitdirenv);
 410                 free(gitfile);
 411                 return NULL;
 412         }
 413
 414         offset = dir_inside_of(cwd, worktree);
 415         if (offset >= 0) {      /* cwd inside worktree? */
 416                 set_git_dir(real_path(gitdirenv));
 417                 if (chdir(worktree))
 418                         die_errno("Could not chdir to '%s'", worktree);
 419                 cwd[len++] = '/';
 420                 cwd[len] = '\0';
 421                 free(gitfile);
 422                 return cwd + offset;
 423         }
 424
 425         /* cwd outside worktree */
 426         set_git_dir(gitdirenv);
 427         free(gitfile);
 428         return NULL;
 429 }
 430
 431 static const char *setup_discovered_git_dir(const char *gitdir,
 432                                             char *cwd, int offset, int len,
 433                                             int *nongit_ok)
 434 {
 435         if (check_repository_format_gently(gitdir, nongit_ok))
 436                 return NULL;
 437
 438         /* --work-tree is set without --git-dir; use discovered one */
 439         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 440                 if (offset != len && !is_absolute_path(gitdir))
 441                         gitdir = xstrdup(real_path(gitdir));
 442                 if (chdir(cwd))
 443                         die_errno("Could not come back to cwd");
 444                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 445         }
 446
 447         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 448         if (is_bare_repository_cfg > 0) {
 449                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 450                 if (chdir(cwd))
 451                         die_errno("Could not come back to cwd");
 452                 return NULL;
 453         }
 454
 455         /* #0, #1, #5, #8, #9, #12, #13 */
 456         set_git_work_tree(".");
 457         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 458                 set_git_dir(gitdir);
 459         inside_git_dir = 0;
 460         inside_work_tree = 1;
 461         if (offset == len)
 462                 return NULL;
 463
 464         /* Make "offset" point to past the '/', and add a '/' at the end */
 465         offset++;
 466         cwd[len++] = '/';
 467         cwd[len] = 0;
 468         return cwd + offset;
 469 }
 470
 471 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 472 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 473 {
 474         int root_len;
 475
 476         if (check_repository_format_gently(".", nongit_ok))
 477                 return NULL;
 478
 479         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 480
 481         /* --work-tree is set without --git-dir; use discovered one */
 482         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 483                 const char *gitdir;
 484
 485                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 486                 if (chdir(cwd))
 487                         die_errno("Could not come back to cwd");
 488                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 489         }
 490
 491         inside_git_dir = 1;
 492         inside_work_tree = 0;
 493         if (offset != len) {
 494                 if (chdir(cwd))
 495                         die_errno("Cannot come back to cwd");
 496                 root_len = offset_1st_component(cwd);
 497                 cwd[offset > root_len ? offset : root_len] = '\0';
 498                 set_git_dir(cwd);
 499         }
 500         else
 501                 set_git_dir(".");
 502         return NULL;
 503 }
 504
 505 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 506 {
 507         if (!nongit_ok)
 508                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 509         if (chdir(cwd))
 510                 die_errno("Cannot come back to cwd");
 511         *nongit_ok = 1;
 512         return NULL;
 513 }
 514
 515 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 516 {
 517         struct stat buf;
 518         if (stat(path, &buf)) {
 519                 die_errno("failed to stat '%*s%s%s'",
 520                                 prefix_len,
 521                                 prefix ? prefix : "",
 522                                 prefix ? "/" : "", path);
 523         }
 524         return buf.st_dev;
 525 }
 526
 527 /*
 528  * A "string_list_each_func_t" function that canonicalizes an entry
 529  * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 530  * discards it if unusable.  The presence of an empty entry in
 531  * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 532  * subsequent entries.
 533  */
 534 static int canonicalize_ceiling_entry(struct string_list_item *item,
 535                                       void *cb_data)
 536 {
 537         int *empty_entry_found = cb_data;
 538         char *ceil = item->string;
 539
 540         if (!*ceil) {
 541                 *empty_entry_found = 1;
 542                 return 0;
 543         } else if (!is_absolute_path(ceil)) {
 544                 return 0;
 545         } else if (*empty_entry_found) {
 546                 /* Keep entry but do not canonicalize it */
 547                 return 1;
 548         } else {
 549                 const char *real_path = real_path_if_valid(ceil);
 550                 if (!real_path)
 551                         return 0;
 552                 free(item->string);
 553                 item->string = xstrdup(real_path);
 554                 return 1;
 555         }
 556 }
 557
 558 /*
 559  * We cannot decide in this function whether we are in the work tree or
 560  * not, since the config can only be read _after_ this function was called.
 561  */
 562 static const char *setup_git_directory_gently_1(int *nongit_ok)
 563 {
 564         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 565         struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 566         static char cwd[PATH_MAX + 1];
 567         const char *gitdirenv, *ret;
 568         char *gitfile;
 569         int len, offset, offset_parent, ceil_offset = -1;
 570         dev_t current_device = 0;
 571         int one_filesystem = 1;
 572
 573         /*
 574          * Let's assume that we are in a git repository.
 575          * If it turns out later that we are somewhere else, the value will be
 576          * updated accordingly.
 577          */
 578         if (nongit_ok)
 579                 *nongit_ok = 0;
 580
 581         if (!getcwd(cwd, sizeof(cwd) - 1))
 582                 die_errno("Unable to read current working directory");
 583         offset = len = strlen(cwd);
 584
 585         /*
 586          * If GIT_DIR is set explicitly, we're not going
 587          * to do any discovery, but we still do repository
 588          * validation.
 589          */
 590         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 591         if (gitdirenv)
 592                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 593
 594         if (env_ceiling_dirs) {
 595                 int empty_entry_found = 0;
 596
 597                 string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 598                 filter_string_list(&ceiling_dirs, 0,
 599                                    canonicalize_ceiling_entry, &empty_entry_found);
 600                 ceil_offset = longest_ancestor_length(cwd, &ceiling_dirs);
 601                 string_list_clear(&ceiling_dirs, 0);
 602         }
 603
 604         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 605                 ceil_offset = 1;
 606
 607         /*
 608          * Test in the following order (relative to the cwd):
 609          * - .git (file containing "gitdir: <path>")
 610          * - .git/
 611          * - ./ (bare)
 612          * - ../.git
 613          * - ../.git/
 614          * - ../ (bare)
 615          * - ../../.git/
 616          *   etc.
 617          */
 618         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 619         if (one_filesystem)
 620                 current_device = get_device_or_die(".", NULL, 0);
 621         for (;;) {
 622                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 623                 if (gitfile)
 624                         gitdirenv = gitfile = xstrdup(gitfile);
 625                 else {
 626                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 627                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 628                 }
 629
 630                 if (gitdirenv) {
 631                         ret = setup_discovered_git_dir(gitdirenv,
 632                                                        cwd, offset, len,
 633                                                        nongit_ok);
 634                         free(gitfile);
 635                         return ret;
 636                 }
 637                 free(gitfile);
 638
 639                 if (is_git_directory("."))
 640                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 641
 642                 offset_parent = offset;
 643                 while (--offset_parent > ceil_offset && cwd[offset_parent] != '/');
 644                 if (offset_parent <= ceil_offset)
 645                         return setup_nongit(cwd, nongit_ok);
 646                 if (one_filesystem) {
 647                         dev_t parent_device = get_device_or_die("..", cwd, offset);
 648                         if (parent_device != current_device) {
 649                                 if (nongit_ok) {
 650                                         if (chdir(cwd))
 651                                                 die_errno("Cannot come back to cwd");
 652                                         *nongit_ok = 1;
 653                                         return NULL;
 654                                 }
 655                                 cwd[offset] = '\0';
 656                                 die("Not a git repository (or any parent up to mount point %s)\n"
 657                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 658                         }
 659                 }
 660                 if (chdir("..")) {
 661                         cwd[offset] = '\0';
 662                         die_errno("Cannot change to '%s/..'", cwd);
 663                 }
 664                 offset = offset_parent;
 665         }
 666 }
 667
 668 const char *setup_git_directory_gently(int *nongit_ok)
 669 {
 670         const char *prefix;
 671
 672         prefix = setup_git_directory_gently_1(nongit_ok);
 673         if (prefix)
 674                 setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 675         else
 676                 setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 677
 678         if (startup_info) {
 679                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 680                 startup_info->prefix = prefix;
 681         }
 682         return prefix;
 683 }
 684
 685 int git_config_perm(const char *var, const char *value)
 686 {
 687         int i;
 688         char *endptr;
 689
 690         if (value == NULL)
 691                 return PERM_GROUP;
 692
 693         if (!strcmp(value, "umask"))
 694                 return PERM_UMASK;
 695         if (!strcmp(value, "group"))
 696                 return PERM_GROUP;
 697         if (!strcmp(value, "all") ||
 698             !strcmp(value, "world") ||
 699             !strcmp(value, "everybody"))
 700                 return PERM_EVERYBODY;
 701
 702         /* Parse octal numbers */
 703         i = strtol(value, &endptr, 8);
 704
 705         /* If not an octal number, maybe true/false? */
 706         if (*endptr != 0)
 707                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 708
 709         /*
 710          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 711          * a chmod value to restrict to.
 712          */
 713         switch (i) {
 714         case PERM_UMASK:               /* 0 */
 715                 return PERM_UMASK;
 716         case OLD_PERM_GROUP:           /* 1 */
 717                 return PERM_GROUP;
 718         case OLD_PERM_EVERYBODY:       /* 2 */
 719                 return PERM_EVERYBODY;
 720         }
 721
 722         /* A filemode value was given: 0xxx */
 723
 724         if ((i & 0600) != 0600)
 725                 die("Problem with core.sharedRepository filemode value "
 726                     "(0%.3o).\nThe owner of files must always have "
 727                     "read and write permissions.", i);
 728
 729         /*
 730          * Mask filemode value. Others can not get write permission.
 731          * x flags for directories are handled separately.
 732          */
 733         return -(i & 0666);
 734 }
 735
 736 int check_repository_format_version(const char *var, const char *value, void *cb)
 737 {
 738         if (strcmp(var, "core.repositoryformatversion") == 0)
 739                 repository_format_version = git_config_int(var, value);
 740         else if (strcmp(var, "core.sharedrepository") == 0)
 741                 shared_repository = git_config_perm(var, value);
 742         else if (strcmp(var, "core.bare") == 0) {
 743                 is_bare_repository_cfg = git_config_bool(var, value);
 744                 if (is_bare_repository_cfg == 1)
 745                         inside_work_tree = -1;
 746         } else if (strcmp(var, "core.worktree") == 0) {
 747                 if (!value)
 748                         return config_error_nonbool(var);
 749                 free(git_work_tree_cfg);
 750                 git_work_tree_cfg = xstrdup(value);
 751                 inside_work_tree = -1;
 752         }
 753         return 0;
 754 }
 755
 756 int check_repository_format(void)
 757 {
 758         return check_repository_format_gently(get_git_dir(), NULL);
 759 }
 760
 761 /*
 762  * Returns the "prefix", a path to the current working directory
 763  * relative to the work tree root, or NULL, if the current working
 764  * directory is not a strict subdirectory of the work tree root. The
 765  * prefix always ends with a '/' character.
 766  */
 767 const char *setup_git_directory(void)
 768 {
 769         return setup_git_directory_gently(NULL);
 770 }
 771
 772 const char *resolve_gitdir(const char *suspect)
 773 {
 774         if (is_git_directory(suspect))
 775                 return suspect;
 776         return read_gitfile(suspect);
 777 }
 778
 779 /* if any standard file descriptor is missing open it to /dev/null */
 780 void sanitize_stdfds(void)
 781 {
 782         int fd = open("/dev/null", O_RDWR, 0);
 783         while (fd != -1 && fd < 2)
 784                 fd = dup(fd);
 785         if (fd == -1)
 786                 die_errno("open /dev/null or dup failed");
 787         if (fd > 2)
 788                 close(fd);
 789 }