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 char *prefix_path(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                         die("'%s' is outside repository", orig);
  35                 }
  36                 if (sanitized[len] == '/')
  37                         len++;
  38                 memmove(sanitized, sanitized + len, total - len);
  39         }
  40         return sanitized;
  41 }
  42
  43 int check_filename(const char *prefix, const char *arg)
  44 {
  45         const char *name;
  46         struct stat st;
  47
  48         name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
  49         if (!lstat(name, &st))
  50                 return 1; /* file exists */
  51         if (errno == ENOENT || errno == ENOTDIR)
  52                 return 0; /* file does not exist */
  53         die_errno("failed to stat '%s'", arg);
  54 }
  55
  56 static void NORETURN die_verify_filename(const char *prefix, const char *arg)
  57 {
  58         unsigned char sha1[20];
  59         unsigned mode;
  60
  61         /*
  62          * Saying "'(icase)foo' does not exist in the index" when the
  63          * user gave us ":(icase)foo" is just stupid.  A magic pathspec
  64          * begins with a colon and is followed by a non-alnum; do not
  65          * let get_sha1_with_mode_1(only_to_die=1) to even trigger.
  66          */
  67         if (!(arg[0] == ':' && !isalnum(arg[1])))
  68                 /* try a detailed diagnostic ... */
  69                 get_sha1_with_mode_1(arg, sha1, &mode, 1, prefix);
  70
  71         /* ... or fall back the most general message. */
  72         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
  73             "Use '--' to separate paths from revisions", arg);
  74
  75 }
  76
  77 /*
  78  * Verify a filename that we got as an argument for a pathspec
  79  * entry. Note that a filename that begins with "-" never verifies
  80  * as true, because even if such a filename were to exist, we want
  81  * it to be preceded by the "--" marker (or we want the user to
  82  * use a format like "./-filename")
  83  */
  84 void verify_filename(const char *prefix, const char *arg)
  85 {
  86         if (*arg == '-')
  87                 die("bad flag '%s' used after filename", arg);
  88         if (check_filename(prefix, arg))
  89                 return;
  90         die_verify_filename(prefix, arg);
  91 }
  92
  93 /*
  94  * Opposite of the above: the command line did not have -- marker
  95  * and we parsed the arg as a refname.  It should not be interpretable
  96  * as a filename.
  97  */
  98 void verify_non_filename(const char *prefix, const char *arg)
  99 {
 100         if (!is_inside_work_tree() || is_inside_git_dir())
 101                 return;
 102         if (*arg == '-')
 103                 return; /* flag */
 104         if (!check_filename(prefix, arg))
 105                 return;
 106         die("ambiguous argument '%s': both revision and filename\n"
 107             "Use '--' to separate filenames from revisions", arg);
 108 }
 109
 110 /*
 111  * Magic pathspec
 112  *
 113  * NEEDSWORK: These need to be moved to dir.h or even to a new
 114  * pathspec.h when we restructure get_pathspec() users to use the
 115  * "struct pathspec" interface.
 116  *
 117  * Possible future magic semantics include stuff like:
 118  *
 119  *      { PATHSPEC_NOGLOB, '!', "noglob" },
 120  *      { PATHSPEC_ICASE, '\0', "icase" },
 121  *      { PATHSPEC_RECURSIVE, '*', "recursive" },
 122  *      { PATHSPEC_REGEXP, '\0', "regexp" },
 123  *
 124  */
 125 #define PATHSPEC_FROMTOP    (1<<0)
 126
 127 static struct pathspec_magic {
 128         unsigned bit;
 129         char mnemonic; /* this cannot be ':'! */
 130         const char *name;
 131 } pathspec_magic[] = {
 132         { PATHSPEC_FROMTOP, '/', "top" },
 133 };
 134
 135 /*
 136  * Take an element of a pathspec and check for magic signatures.
 137  * Append the result to the prefix.
 138  *
 139  * For now, we only parse the syntax and throw out anything other than
 140  * "top" magic.
 141  *
 142  * NEEDSWORK: This needs to be rewritten when we start migrating
 143  * get_pathspec() users to use the "struct pathspec" interface.  For
 144  * example, a pathspec element may be marked as case-insensitive, but
 145  * the prefix part must always match literally, and a single stupid
 146  * string cannot express such a case.
 147  */
 148 static const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
 149 {
 150         unsigned magic = 0;
 151         const char *copyfrom = elt;
 152         int i;
 153
 154         if (elt[0] != ':') {
 155                 ; /* nothing to do */
 156         } else if (elt[1] == '(') {
 157                 /* longhand */
 158                 const char *nextat;
 159                 for (copyfrom = elt + 2;
 160                      *copyfrom && *copyfrom != ')';
 161                      copyfrom = nextat) {
 162                         size_t len = strcspn(copyfrom, ",)");
 163                         if (copyfrom[len] == ')')
 164                                 nextat = copyfrom + len;
 165                         else
 166                                 nextat = copyfrom + len + 1;
 167                         if (!len)
 168                                 continue;
 169                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 170                                 if (strlen(pathspec_magic[i].name) == len &&
 171                                     !strncmp(pathspec_magic[i].name, copyfrom, len)) {
 172                                         magic |= pathspec_magic[i].bit;
 173                                         break;
 174                                 }
 175                         if (ARRAY_SIZE(pathspec_magic) <= i)
 176                                 die("Invalid pathspec magic '%.*s' in '%s'",
 177                                     (int) len, copyfrom, elt);
 178                 }
 179                 if (*copyfrom == ')')
 180                         copyfrom++;
 181         } else {
 182                 /* shorthand */
 183                 for (copyfrom = elt + 1;
 184                      *copyfrom && *copyfrom != ':';
 185                      copyfrom++) {
 186                         char ch = *copyfrom;
 187
 188                         if (!is_pathspec_magic(ch))
 189                                 break;
 190                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 191                                 if (pathspec_magic[i].mnemonic == ch) {
 192                                         magic |= pathspec_magic[i].bit;
 193                                         break;
 194                                 }
 195                         if (ARRAY_SIZE(pathspec_magic) <= i)
 196                                 die("Unimplemented pathspec magic '%c' in '%s'",
 197                                     ch, elt);
 198                 }
 199                 if (*copyfrom == ':')
 200                         copyfrom++;
 201         }
 202
 203         if (magic & PATHSPEC_FROMTOP)
 204                 return xstrdup(copyfrom);
 205         else
 206                 return prefix_path(prefix, prefixlen, copyfrom);
 207 }
 208
 209 const char **get_pathspec(const char *prefix, const char **pathspec)
 210 {
 211         const char *entry = *pathspec;
 212         const char **src, **dst;
 213         int prefixlen;
 214
 215         if (!prefix && !entry)
 216                 return NULL;
 217
 218         if (!entry) {
 219                 static const char *spec[2];
 220                 spec[0] = prefix;
 221                 spec[1] = NULL;
 222                 return spec;
 223         }
 224
 225         /* Otherwise we have to re-write the entries.. */
 226         src = pathspec;
 227         dst = pathspec;
 228         prefixlen = prefix ? strlen(prefix) : 0;
 229         while (*src) {
 230                 *(dst++) = prefix_pathspec(prefix, prefixlen, *src);
 231                 src++;
 232         }
 233         *dst = NULL;
 234         if (!*pathspec)
 235                 return NULL;
 236         return pathspec;
 237 }
 238
 239 /*
 240  * Test if it looks like we're at a git directory.
 241  * We want to see:
 242  *
 243  *  - either an objects/ directory _or_ the proper
 244  *    GIT_OBJECT_DIRECTORY environment variable
 245  *  - a refs/ directory
 246  *  - either a HEAD symlink or a HEAD file that is formatted as
 247  *    a proper "ref:", or a regular file HEAD that has a properly
 248  *    formatted sha1 object name.
 249  */
 250 int is_git_directory(const char *suspect)
 251 {
 252         char path[PATH_MAX];
 253         size_t len = strlen(suspect);
 254
 255         if (PATH_MAX <= len + strlen("/objects"))
 256                 die("Too long path: %.*s", 60, suspect);
 257         strcpy(path, suspect);
 258         if (getenv(DB_ENVIRONMENT)) {
 259                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 260                         return 0;
 261         }
 262         else {
 263                 strcpy(path + len, "/objects");
 264                 if (access(path, X_OK))
 265                         return 0;
 266         }
 267
 268         strcpy(path + len, "/refs");
 269         if (access(path, X_OK))
 270                 return 0;
 271
 272         strcpy(path + len, "/HEAD");
 273         if (validate_headref(path))
 274                 return 0;
 275
 276         return 1;
 277 }
 278
 279 int is_inside_git_dir(void)
 280 {
 281         if (inside_git_dir < 0)
 282                 inside_git_dir = is_inside_dir(get_git_dir());
 283         return inside_git_dir;
 284 }
 285
 286 int is_inside_work_tree(void)
 287 {
 288         if (inside_work_tree < 0)
 289                 inside_work_tree = is_inside_dir(get_git_work_tree());
 290         return inside_work_tree;
 291 }
 292
 293 void setup_work_tree(void)
 294 {
 295         const char *work_tree, *git_dir;
 296         static int initialized = 0;
 297
 298         if (initialized)
 299                 return;
 300         work_tree = get_git_work_tree();
 301         git_dir = get_git_dir();
 302         if (!is_absolute_path(git_dir))
 303                 git_dir = real_path(get_git_dir());
 304         if (!work_tree || chdir(work_tree))
 305                 die("This operation must be run in a work tree");
 306
 307         /*
 308          * Make sure subsequent git processes find correct worktree
 309          * if $GIT_WORK_TREE is set relative
 310          */
 311         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 312                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 313
 314         set_git_dir(relative_path(git_dir, work_tree));
 315         initialized = 1;
 316 }
 317
 318 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 319 {
 320         char repo_config[PATH_MAX+1];
 321
 322         /*
 323          * git_config() can't be used here because it calls git_pathdup()
 324          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 325          * set git_dir to ".git".
 326          *
 327          * We are in gitdir setup, no git dir has been found useable yet.
 328          * Use a gentler version of git_config() to check if this repo
 329          * is a good one.
 330          */
 331         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 332         git_config_early(check_repository_format_version, NULL, repo_config);
 333         if (GIT_REPO_VERSION < repository_format_version) {
 334                 if (!nongit_ok)
 335                         die ("Expected git repo version <= %d, found %d",
 336                              GIT_REPO_VERSION, repository_format_version);
 337                 warning("Expected git repo version <= %d, found %d",
 338                         GIT_REPO_VERSION, repository_format_version);
 339                 warning("Please upgrade Git");
 340                 *nongit_ok = -1;
 341                 return -1;
 342         }
 343         return 0;
 344 }
 345
 346 /*
 347  * Try to read the location of the git directory from the .git file,
 348  * return path to git directory if found.
 349  */
 350 const char *read_gitfile(const char *path)
 351 {
 352         char *buf;
 353         char *dir;
 354         const char *slash;
 355         struct stat st;
 356         int fd;
 357         ssize_t len;
 358
 359         if (stat(path, &st))
 360                 return NULL;
 361         if (!S_ISREG(st.st_mode))
 362                 return NULL;
 363         fd = open(path, O_RDONLY);
 364         if (fd < 0)
 365                 die_errno("Error opening '%s'", path);
 366         buf = xmalloc(st.st_size + 1);
 367         len = read_in_full(fd, buf, st.st_size);
 368         close(fd);
 369         if (len != st.st_size)
 370                 die("Error reading %s", path);
 371         buf[len] = '\0';
 372         if (prefixcmp(buf, "gitdir: "))
 373                 die("Invalid gitfile format: %s", path);
 374         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 375                 len--;
 376         if (len < 9)
 377                 die("No path in gitfile: %s", path);
 378         buf[len] = '\0';
 379         dir = buf + 8;
 380
 381         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 382                 size_t pathlen = slash+1 - path;
 383                 size_t dirlen = pathlen + len - 8;
 384                 dir = xmalloc(dirlen + 1);
 385                 strncpy(dir, path, pathlen);
 386                 strncpy(dir + pathlen, buf + 8, len - 8);
 387                 dir[dirlen] = '\0';
 388                 free(buf);
 389                 buf = dir;
 390         }
 391
 392         if (!is_git_directory(dir))
 393                 die("Not a git repository: %s", dir);
 394         path = real_path(dir);
 395
 396         free(buf);
 397         return path;
 398 }
 399
 400 static const char *setup_explicit_git_dir(const char *gitdirenv,
 401                                           char *cwd, int len,
 402                                           int *nongit_ok)
 403 {
 404         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 405         const char *worktree;
 406         char *gitfile;
 407         int offset;
 408
 409         if (PATH_MAX - 40 < strlen(gitdirenv))
 410                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 411
 412         gitfile = (char*)read_gitfile(gitdirenv);
 413         if (gitfile) {
 414                 gitfile = xstrdup(gitfile);
 415                 gitdirenv = gitfile;
 416         }
 417
 418         if (!is_git_directory(gitdirenv)) {
 419                 if (nongit_ok) {
 420                         *nongit_ok = 1;
 421                         free(gitfile);
 422                         return NULL;
 423                 }
 424                 die("Not a git repository: '%s'", gitdirenv);
 425         }
 426
 427         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 428                 free(gitfile);
 429                 return NULL;
 430         }
 431
 432         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 433         if (work_tree_env)
 434                 set_git_work_tree(work_tree_env);
 435         else if (is_bare_repository_cfg > 0) {
 436                 if (git_work_tree_cfg) /* #22.2, #30 */
 437                         die("core.bare and core.worktree do not make sense");
 438
 439                 /* #18, #26 */
 440                 set_git_dir(gitdirenv);
 441                 free(gitfile);
 442                 return NULL;
 443         }
 444         else if (git_work_tree_cfg) { /* #6, #14 */
 445                 if (is_absolute_path(git_work_tree_cfg))
 446                         set_git_work_tree(git_work_tree_cfg);
 447                 else {
 448                         char core_worktree[PATH_MAX];
 449                         if (chdir(gitdirenv))
 450                                 die_errno("Could not chdir to '%s'", gitdirenv);
 451                         if (chdir(git_work_tree_cfg))
 452                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 453                         if (!getcwd(core_worktree, PATH_MAX))
 454                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 455                         if (chdir(cwd))
 456                                 die_errno("Could not come back to cwd");
 457                         set_git_work_tree(core_worktree);
 458                 }
 459         }
 460         else /* #2, #10 */
 461                 set_git_work_tree(".");
 462
 463         /* set_git_work_tree() must have been called by now */
 464         worktree = get_git_work_tree();
 465
 466         /* both get_git_work_tree() and cwd are already normalized */
 467         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 468                 set_git_dir(gitdirenv);
 469                 free(gitfile);
 470                 return NULL;
 471         }
 472
 473         offset = dir_inside_of(cwd, worktree);
 474         if (offset >= 0) {      /* cwd inside worktree? */
 475                 set_git_dir(real_path(gitdirenv));
 476                 if (chdir(worktree))
 477                         die_errno("Could not chdir to '%s'", worktree);
 478                 cwd[len++] = '/';
 479                 cwd[len] = '\0';
 480                 free(gitfile);
 481                 return cwd + offset;
 482         }
 483
 484         /* cwd outside worktree */
 485         set_git_dir(gitdirenv);
 486         free(gitfile);
 487         return NULL;
 488 }
 489
 490 static const char *setup_discovered_git_dir(const char *gitdir,
 491                                             char *cwd, int offset, int len,
 492                                             int *nongit_ok)
 493 {
 494         if (check_repository_format_gently(gitdir, nongit_ok))
 495                 return NULL;
 496
 497         /* --work-tree is set without --git-dir; use discovered one */
 498         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 499                 if (offset != len && !is_absolute_path(gitdir))
 500                         gitdir = xstrdup(real_path(gitdir));
 501                 if (chdir(cwd))
 502                         die_errno("Could not come back to cwd");
 503                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 504         }
 505
 506         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 507         if (is_bare_repository_cfg > 0) {
 508                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 509                 if (chdir(cwd))
 510                         die_errno("Could not come back to cwd");
 511                 return NULL;
 512         }
 513
 514         /* #0, #1, #5, #8, #9, #12, #13 */
 515         set_git_work_tree(".");
 516         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 517                 set_git_dir(gitdir);
 518         inside_git_dir = 0;
 519         inside_work_tree = 1;
 520         if (offset == len)
 521                 return NULL;
 522
 523         /* Make "offset" point to past the '/', and add a '/' at the end */
 524         offset++;
 525         cwd[len++] = '/';
 526         cwd[len] = 0;
 527         return cwd + offset;
 528 }
 529
 530 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 531 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 532 {
 533         int root_len;
 534
 535         if (check_repository_format_gently(".", nongit_ok))
 536                 return NULL;
 537
 538         /* --work-tree is set without --git-dir; use discovered one */
 539         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 540                 const char *gitdir;
 541
 542                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 543                 if (chdir(cwd))
 544                         die_errno("Could not come back to cwd");
 545                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 546         }
 547
 548         inside_git_dir = 1;
 549         inside_work_tree = 0;
 550         if (offset != len) {
 551                 if (chdir(cwd))
 552                         die_errno("Cannot come back to cwd");
 553                 root_len = offset_1st_component(cwd);
 554                 cwd[offset > root_len ? offset : root_len] = '\0';
 555                 set_git_dir(cwd);
 556         }
 557         else
 558                 set_git_dir(".");
 559         return NULL;
 560 }
 561
 562 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 563 {
 564         if (!nongit_ok)
 565                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 566         if (chdir(cwd))
 567                 die_errno("Cannot come back to cwd");
 568         *nongit_ok = 1;
 569         return NULL;
 570 }
 571
 572 static dev_t get_device_or_die(const char *path, const char *prefix)
 573 {
 574         struct stat buf;
 575         if (stat(path, &buf))
 576                 die_errno("failed to stat '%s%s%s'",
 577                                 prefix ? prefix : "",
 578                                 prefix ? "/" : "", path);
 579         return buf.st_dev;
 580 }
 581
 582 /*
 583  * We cannot decide in this function whether we are in the work tree or
 584  * not, since the config can only be read _after_ this function was called.
 585  */
 586 static const char *setup_git_directory_gently_1(int *nongit_ok)
 587 {
 588         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 589         static char cwd[PATH_MAX+1];
 590         const char *gitdirenv, *ret;
 591         char *gitfile;
 592         int len, offset, ceil_offset;
 593         dev_t current_device = 0;
 594         int one_filesystem = 1;
 595
 596         /*
 597          * Let's assume that we are in a git repository.
 598          * If it turns out later that we are somewhere else, the value will be
 599          * updated accordingly.
 600          */
 601         if (nongit_ok)
 602                 *nongit_ok = 0;
 603
 604         if (!getcwd(cwd, sizeof(cwd)-1))
 605                 die_errno("Unable to read current working directory");
 606         offset = len = strlen(cwd);
 607
 608         /*
 609          * If GIT_DIR is set explicitly, we're not going
 610          * to do any discovery, but we still do repository
 611          * validation.
 612          */
 613         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 614         if (gitdirenv)
 615                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 616
 617         ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
 618         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 619                 ceil_offset = 1;
 620
 621         /*
 622          * Test in the following order (relative to the cwd):
 623          * - .git (file containing "gitdir: <path>")
 624          * - .git/
 625          * - ./ (bare)
 626          * - ../.git
 627          * - ../.git/
 628          * - ../ (bare)
 629          * - ../../.git/
 630          *   etc.
 631          */
 632         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 633         if (one_filesystem)
 634                 current_device = get_device_or_die(".", NULL);
 635         for (;;) {
 636                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 637                 if (gitfile)
 638                         gitdirenv = gitfile = xstrdup(gitfile);
 639                 else {
 640                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 641                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 642                 }
 643
 644                 if (gitdirenv) {
 645                         ret = setup_discovered_git_dir(gitdirenv,
 646                                                        cwd, offset, len,
 647                                                        nongit_ok);
 648                         free(gitfile);
 649                         return ret;
 650                 }
 651                 free(gitfile);
 652
 653                 if (is_git_directory("."))
 654                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 655
 656                 while (--offset > ceil_offset && cwd[offset] != '/');
 657                 if (offset <= ceil_offset)
 658                         return setup_nongit(cwd, nongit_ok);
 659                 if (one_filesystem) {
 660                         dev_t parent_device = get_device_or_die("..", cwd);
 661                         if (parent_device != current_device) {
 662                                 if (nongit_ok) {
 663                                         if (chdir(cwd))
 664                                                 die_errno("Cannot come back to cwd");
 665                                         *nongit_ok = 1;
 666                                         return NULL;
 667                                 }
 668                                 cwd[offset] = '\0';
 669                                 die("Not a git repository (or any parent up to mount parent %s)\n"
 670                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 671                         }
 672                 }
 673                 if (chdir("..")) {
 674                         cwd[offset] = '\0';
 675                         die_errno("Cannot change to '%s/..'", cwd);
 676                 }
 677         }
 678 }
 679
 680 const char *setup_git_directory_gently(int *nongit_ok)
 681 {
 682         const char *prefix;
 683
 684         prefix = setup_git_directory_gently_1(nongit_ok);
 685         if (prefix)
 686                 setenv("GIT_PREFIX", prefix, 1);
 687         else
 688                 setenv("GIT_PREFIX", "", 1);
 689
 690         if (startup_info) {
 691                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 692                 startup_info->prefix = prefix;
 693         }
 694         return prefix;
 695 }
 696
 697 int git_config_perm(const char *var, const char *value)
 698 {
 699         int i;
 700         char *endptr;
 701
 702         if (value == NULL)
 703                 return PERM_GROUP;
 704
 705         if (!strcmp(value, "umask"))
 706                 return PERM_UMASK;
 707         if (!strcmp(value, "group"))
 708                 return PERM_GROUP;
 709         if (!strcmp(value, "all") ||
 710             !strcmp(value, "world") ||
 711             !strcmp(value, "everybody"))
 712                 return PERM_EVERYBODY;
 713
 714         /* Parse octal numbers */
 715         i = strtol(value, &endptr, 8);
 716
 717         /* If not an octal number, maybe true/false? */
 718         if (*endptr != 0)
 719                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 720
 721         /*
 722          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 723          * a chmod value to restrict to.
 724          */
 725         switch (i) {
 726         case PERM_UMASK:               /* 0 */
 727                 return PERM_UMASK;
 728         case OLD_PERM_GROUP:           /* 1 */
 729                 return PERM_GROUP;
 730         case OLD_PERM_EVERYBODY:       /* 2 */
 731                 return PERM_EVERYBODY;
 732         }
 733
 734         /* A filemode value was given: 0xxx */
 735
 736         if ((i & 0600) != 0600)
 737                 die("Problem with core.sharedRepository filemode value "
 738                     "(0%.3o).\nThe owner of files must always have "
 739                     "read and write permissions.", i);
 740
 741         /*
 742          * Mask filemode value. Others can not get write permission.
 743          * x flags for directories are handled separately.
 744          */
 745         return -(i & 0666);
 746 }
 747
 748 int check_repository_format_version(const char *var, const char *value, void *cb)
 749 {
 750         if (strcmp(var, "core.repositoryformatversion") == 0)
 751                 repository_format_version = git_config_int(var, value);
 752         else if (strcmp(var, "core.sharedrepository") == 0)
 753                 shared_repository = git_config_perm(var, value);
 754         else if (strcmp(var, "core.bare") == 0) {
 755                 is_bare_repository_cfg = git_config_bool(var, value);
 756                 if (is_bare_repository_cfg == 1)
 757                         inside_work_tree = -1;
 758         } else if (strcmp(var, "core.worktree") == 0) {
 759                 if (!value)
 760                         return config_error_nonbool(var);
 761                 free(git_work_tree_cfg);
 762                 git_work_tree_cfg = xstrdup(value);
 763                 inside_work_tree = -1;
 764         }
 765         return 0;
 766 }
 767
 768 int check_repository_format(void)
 769 {
 770         return check_repository_format_gently(get_git_dir(), NULL);
 771 }
 772
 773 /*
 774  * Returns the "prefix", a path to the current working directory
 775  * relative to the work tree root, or NULL, if the current working
 776  * directory is not a strict subdirectory of the work tree root. The
 777  * prefix always ends with a '/' character.
 778  */
 779 const char *setup_git_directory(void)
 780 {
 781         return setup_git_directory_gently(NULL);
 782 }
 783
 784 const char *resolve_gitdir(const char *suspect)
 785 {
 786         if (is_git_directory(suspect))
 787                 return suspect;
 788         return read_gitfile(suspect);
 789 }