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 /*
  44  * Unlike prefix_path, this should be used if the named file does
  45  * not have to interact with index entry; i.e. name of a random file
  46  * on the filesystem.
  47  */
  48 const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
  49 {
  50         static char path[PATH_MAX];
  51 #ifndef WIN32
  52         if (!pfx_len || is_absolute_path(arg))
  53                 return arg;
  54         memcpy(path, pfx, pfx_len);
  55         strcpy(path + pfx_len, arg);
  56 #else
  57         char *p;
  58         /* don't add prefix to absolute paths, but still replace '\' by '/' */
  59         if (is_absolute_path(arg))
  60                 pfx_len = 0;
  61         else if (pfx_len)
  62                 memcpy(path, pfx, pfx_len);
  63         strcpy(path + pfx_len, arg);
  64         for (p = path + pfx_len; *p; p++)
  65                 if (*p == '\\')
  66                         *p = '/';
  67 #endif
  68         return path;
  69 }
  70
  71 int check_filename(const char *prefix, const char *arg)
  72 {
  73         const char *name;
  74         struct stat st;
  75
  76         name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
  77         if (!lstat(name, &st))
  78                 return 1; /* file exists */
  79         if (errno == ENOENT || errno == ENOTDIR)
  80                 return 0; /* file does not exist */
  81         die_errno("failed to stat '%s'", arg);
  82 }
  83
  84 static void NORETURN die_verify_filename(const char *prefix, const char *arg)
  85 {
  86         unsigned char sha1[20];
  87         unsigned mode;
  88         /* try a detailed diagnostic ... */
  89         get_sha1_with_mode_1(arg, sha1, &mode, 0, prefix);
  90         /* ... or fall back the most general message. */
  91         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
  92             "Use '--' to separate paths from revisions", arg);
  93
  94 }
  95
  96 /*
  97  * Verify a filename that we got as an argument for a pathspec
  98  * entry. Note that a filename that begins with "-" never verifies
  99  * as true, because even if such a filename were to exist, we want
 100  * it to be preceded by the "--" marker (or we want the user to
 101  * use a format like "./-filename")
 102  */
 103 void verify_filename(const char *prefix, const char *arg)
 104 {
 105         if (*arg == '-')
 106                 die("bad flag '%s' used after filename", arg);
 107         if (check_filename(prefix, arg))
 108                 return;
 109         die_verify_filename(prefix, arg);
 110 }
 111
 112 /*
 113  * Opposite of the above: the command line did not have -- marker
 114  * and we parsed the arg as a refname.  It should not be interpretable
 115  * as a filename.
 116  */
 117 void verify_non_filename(const char *prefix, const char *arg)
 118 {
 119         if (!is_inside_work_tree() || is_inside_git_dir())
 120                 return;
 121         if (*arg == '-')
 122                 return; /* flag */
 123         if (!check_filename(prefix, arg))
 124                 return;
 125         die("ambiguous argument '%s': both revision and filename\n"
 126             "Use '--' to separate filenames from revisions", arg);
 127 }
 128
 129 /*
 130  * Magic pathspec
 131  *
 132  * NEEDSWORK: These need to be moved to dir.h or even to a new
 133  * pathspec.h when we restructure get_pathspec() users to use the
 134  * "struct pathspec" interface.
 135  *
 136  * Possible future magic semantics include stuff like:
 137  *
 138  *      { PATHSPEC_NOGLOB, '!', "noglob" },
 139  *      { PATHSPEC_ICASE, '\0', "icase" },
 140  *      { PATHSPEC_RECURSIVE, '*', "recursive" },
 141  *      { PATHSPEC_REGEXP, '\0', "regexp" },
 142  *
 143  */
 144 #define PATHSPEC_FROMTOP    (1<<0)
 145
 146 struct pathspec_magic {
 147         unsigned bit;
 148         char mnemonic; /* this cannot be ':'! */
 149         const char *name;
 150 } pathspec_magic[] = {
 151         { PATHSPEC_FROMTOP, '/', "top" },
 152 };
 153
 154 /*
 155  * Take an element of a pathspec and check for magic signatures.
 156  * Append the result to the prefix.
 157  *
 158  * For now, we only parse the syntax and throw out anything other than
 159  * "top" magic.
 160  *
 161  * NEEDSWORK: This needs to be rewritten when we start migrating
 162  * get_pathspec() users to use the "struct pathspec" interface.  For
 163  * example, a pathspec element may be marked as case-insensitive, but
 164  * the prefix part must always match literally, and a single stupid
 165  * string cannot express such a case.
 166  */
 167 const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
 168 {
 169         unsigned magic = 0;
 170         const char *copyfrom = elt;
 171         int i;
 172
 173         if (elt[0] != ':') {
 174                 ; /* nothing to do */
 175         } else if (elt[1] == '(') {
 176                 /* longhand */
 177                 const char *nextat;
 178                 for (copyfrom = elt + 2;
 179                      *copyfrom && *copyfrom != ')';
 180                      copyfrom = nextat) {
 181                         size_t len = strcspn(copyfrom, ",)");
 182                         if (copyfrom[len] == ')')
 183                                 nextat = copyfrom + len;
 184                         else
 185                                 nextat = copyfrom + len + 1;
 186                         if (!len)
 187                                 continue;
 188                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 189                                 if (strlen(pathspec_magic[i].name) == len &&
 190                                     !strncmp(pathspec_magic[i].name, copyfrom, len)) {
 191                                         magic |= pathspec_magic[i].bit;
 192                                         break;
 193                                 }
 194                         if (ARRAY_SIZE(pathspec_magic) <= i)
 195                                 die("Invalid pathspec magic '%.*s' in '%s'",
 196                                     (int) len, copyfrom, elt);
 197                 }
 198                 if (*copyfrom == ')')
 199                         copyfrom++;
 200         } else {
 201                 /* shorthand */
 202                 for (copyfrom = elt + 1;
 203                      *copyfrom && *copyfrom != ':';
 204                      copyfrom++) {
 205                         char ch = *copyfrom;
 206
 207                         if (!is_pathspec_magic(ch))
 208                                 break;
 209                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 210                                 if (pathspec_magic[i].mnemonic == ch) {
 211                                         magic |= pathspec_magic[i].bit;
 212                                         break;
 213                                 }
 214                         if (ARRAY_SIZE(pathspec_magic) <= i)
 215                                 die("Unimplemented pathspec magic '%c' in '%s'",
 216                                     ch, elt);
 217                 }
 218                 if (*copyfrom == ':')
 219                         copyfrom++;
 220         }
 221
 222         if (magic & PATHSPEC_FROMTOP)
 223                 return xstrdup(copyfrom);
 224         else
 225                 return prefix_path(prefix, prefixlen, copyfrom);
 226 }
 227
 228 const char **get_pathspec(const char *prefix, const char **pathspec)
 229 {
 230         const char *entry = *pathspec;
 231         const char **src, **dst;
 232         int prefixlen;
 233
 234         if (!prefix && !entry)
 235                 return NULL;
 236
 237         if (!entry) {
 238                 static const char *spec[2];
 239                 spec[0] = prefix;
 240                 spec[1] = NULL;
 241                 return spec;
 242         }
 243
 244         /* Otherwise we have to re-write the entries.. */
 245         src = pathspec;
 246         dst = pathspec;
 247         prefixlen = prefix ? strlen(prefix) : 0;
 248         while (*src) {
 249                 *(dst++) = prefix_pathspec(prefix, prefixlen, *src);
 250                 src++;
 251         }
 252         *dst = NULL;
 253         if (!*pathspec)
 254                 return NULL;
 255         return pathspec;
 256 }
 257
 258 /*
 259  * Test if it looks like we're at a git directory.
 260  * We want to see:
 261  *
 262  *  - either an objects/ directory _or_ the proper
 263  *    GIT_OBJECT_DIRECTORY environment variable
 264  *  - a refs/ directory
 265  *  - either a HEAD symlink or a HEAD file that is formatted as
 266  *    a proper "ref:", or a regular file HEAD that has a properly
 267  *    formatted sha1 object name.
 268  */
 269 static int is_git_directory(const char *suspect)
 270 {
 271         char path[PATH_MAX];
 272         size_t len = strlen(suspect);
 273
 274         if (PATH_MAX <= len + strlen("/objects"))
 275                 die("Too long path: %.*s", 60, suspect);
 276         strcpy(path, suspect);
 277         if (getenv(DB_ENVIRONMENT)) {
 278                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 279                         return 0;
 280         }
 281         else {
 282                 strcpy(path + len, "/objects");
 283                 if (access(path, X_OK))
 284                         return 0;
 285         }
 286
 287         strcpy(path + len, "/refs");
 288         if (access(path, X_OK))
 289                 return 0;
 290
 291         strcpy(path + len, "/HEAD");
 292         if (validate_headref(path))
 293                 return 0;
 294
 295         return 1;
 296 }
 297
 298 int is_inside_git_dir(void)
 299 {
 300         if (inside_git_dir < 0)
 301                 inside_git_dir = is_inside_dir(get_git_dir());
 302         return inside_git_dir;
 303 }
 304
 305 int is_inside_work_tree(void)
 306 {
 307         if (inside_work_tree < 0)
 308                 inside_work_tree = is_inside_dir(get_git_work_tree());
 309         return inside_work_tree;
 310 }
 311
 312 void setup_work_tree(void)
 313 {
 314         const char *work_tree, *git_dir;
 315         static int initialized = 0;
 316
 317         if (initialized)
 318                 return;
 319         work_tree = get_git_work_tree();
 320         git_dir = get_git_dir();
 321         if (!is_absolute_path(git_dir))
 322                 git_dir = real_path(get_git_dir());
 323         if (!work_tree || chdir(work_tree))
 324                 die("This operation must be run in a work tree");
 325
 326         /*
 327          * Make sure subsequent git processes find correct worktree
 328          * if $GIT_WORK_TREE is set relative
 329          */
 330         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 331                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 332
 333         set_git_dir(relative_path(git_dir, work_tree));
 334         initialized = 1;
 335 }
 336
 337 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 338 {
 339         char repo_config[PATH_MAX+1];
 340
 341         /*
 342          * git_config() can't be used here because it calls git_pathdup()
 343          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 344          * set git_dir to ".git".
 345          *
 346          * We are in gitdir setup, no git dir has been found useable yet.
 347          * Use a gentler version of git_config() to check if this repo
 348          * is a good one.
 349          */
 350         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 351         git_config_early(check_repository_format_version, NULL, repo_config);
 352         if (GIT_REPO_VERSION < repository_format_version) {
 353                 if (!nongit_ok)
 354                         die ("Expected git repo version <= %d, found %d",
 355                              GIT_REPO_VERSION, repository_format_version);
 356                 warning("Expected git repo version <= %d, found %d",
 357                         GIT_REPO_VERSION, repository_format_version);
 358                 warning("Please upgrade Git");
 359                 *nongit_ok = -1;
 360                 return -1;
 361         }
 362         return 0;
 363 }
 364
 365 /*
 366  * Try to read the location of the git directory from the .git file,
 367  * return path to git directory if found.
 368  */
 369 const char *read_gitfile_gently(const char *path)
 370 {
 371         char *buf;
 372         char *dir;
 373         const char *slash;
 374         struct stat st;
 375         int fd;
 376         size_t len;
 377
 378         if (stat(path, &st))
 379                 return NULL;
 380         if (!S_ISREG(st.st_mode))
 381                 return NULL;
 382         fd = open(path, O_RDONLY);
 383         if (fd < 0)
 384                 die_errno("Error opening '%s'", path);
 385         buf = xmalloc(st.st_size + 1);
 386         len = read_in_full(fd, buf, st.st_size);
 387         close(fd);
 388         if (len != st.st_size)
 389                 die("Error reading %s", path);
 390         buf[len] = '\0';
 391         if (prefixcmp(buf, "gitdir: "))
 392                 die("Invalid gitfile format: %s", path);
 393         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 394                 len--;
 395         if (len < 9)
 396                 die("No path in gitfile: %s", path);
 397         buf[len] = '\0';
 398         dir = buf + 8;
 399
 400         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 401                 size_t pathlen = slash+1 - path;
 402                 size_t dirlen = pathlen + len - 8;
 403                 dir = xmalloc(dirlen + 1);
 404                 strncpy(dir, path, pathlen);
 405                 strncpy(dir + pathlen, buf + 8, len - 8);
 406                 dir[dirlen] = '\0';
 407                 free(buf);
 408                 buf = dir;
 409         }
 410
 411         if (!is_git_directory(dir))
 412                 die("Not a git repository: %s", dir);
 413         path = real_path(dir);
 414
 415         free(buf);
 416         return path;
 417 }
 418
 419 static const char *setup_explicit_git_dir(const char *gitdirenv,
 420                                           char *cwd, int len,
 421                                           int *nongit_ok)
 422 {
 423         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 424         const char *worktree;
 425         char *gitfile;
 426
 427         if (PATH_MAX - 40 < strlen(gitdirenv))
 428                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 429
 430         gitfile = (char*)read_gitfile_gently(gitdirenv);
 431         if (gitfile) {
 432                 gitfile = xstrdup(gitfile);
 433                 gitdirenv = gitfile;
 434         }
 435
 436         if (!is_git_directory(gitdirenv)) {
 437                 if (nongit_ok) {
 438                         *nongit_ok = 1;
 439                         free(gitfile);
 440                         return NULL;
 441                 }
 442                 die("Not a git repository: '%s'", gitdirenv);
 443         }
 444
 445         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 446                 free(gitfile);
 447                 return NULL;
 448         }
 449
 450         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 451         if (work_tree_env)
 452                 set_git_work_tree(work_tree_env);
 453         else if (is_bare_repository_cfg > 0) {
 454                 if (git_work_tree_cfg) /* #22.2, #30 */
 455                         die("core.bare and core.worktree do not make sense");
 456
 457                 /* #18, #26 */
 458                 set_git_dir(gitdirenv);
 459                 free(gitfile);
 460                 return NULL;
 461         }
 462         else if (git_work_tree_cfg) { /* #6, #14 */
 463                 if (is_absolute_path(git_work_tree_cfg))
 464                         set_git_work_tree(git_work_tree_cfg);
 465                 else {
 466                         char core_worktree[PATH_MAX];
 467                         if (chdir(gitdirenv))
 468                                 die_errno("Could not chdir to '%s'", gitdirenv);
 469                         if (chdir(git_work_tree_cfg))
 470                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 471                         if (!getcwd(core_worktree, PATH_MAX))
 472                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 473                         if (chdir(cwd))
 474                                 die_errno("Could not come back to cwd");
 475                         set_git_work_tree(core_worktree);
 476                 }
 477         }
 478         else /* #2, #10 */
 479                 set_git_work_tree(".");
 480
 481         /* set_git_work_tree() must have been called by now */
 482         worktree = get_git_work_tree();
 483
 484         /* both get_git_work_tree() and cwd are already normalized */
 485         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 486                 set_git_dir(gitdirenv);
 487                 free(gitfile);
 488                 return NULL;
 489         }
 490
 491         if (!prefixcmp(cwd, worktree) &&
 492             cwd[strlen(worktree)] == '/') { /* cwd inside worktree */
 493                 set_git_dir(real_path(gitdirenv));
 494                 if (chdir(worktree))
 495                         die_errno("Could not chdir to '%s'", worktree);
 496                 cwd[len++] = '/';
 497                 cwd[len] = '\0';
 498                 free(gitfile);
 499                 return cwd + strlen(worktree) + 1;
 500         }
 501
 502         /* cwd outside worktree */
 503         set_git_dir(gitdirenv);
 504         free(gitfile);
 505         return NULL;
 506 }
 507
 508 static const char *setup_discovered_git_dir(const char *gitdir,
 509                                             char *cwd, int offset, int len,
 510                                             int *nongit_ok)
 511 {
 512         if (check_repository_format_gently(gitdir, nongit_ok))
 513                 return NULL;
 514
 515         /* --work-tree is set without --git-dir; use discovered one */
 516         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 517                 if (offset != len && !is_absolute_path(gitdir))
 518                         gitdir = xstrdup(real_path(gitdir));
 519                 if (chdir(cwd))
 520                         die_errno("Could not come back to cwd");
 521                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 522         }
 523
 524         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 525         if (is_bare_repository_cfg > 0) {
 526                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 527                 if (chdir(cwd))
 528                         die_errno("Could not come back to cwd");
 529                 return NULL;
 530         }
 531
 532         /* #0, #1, #5, #8, #9, #12, #13 */
 533         set_git_work_tree(".");
 534         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 535                 set_git_dir(gitdir);
 536         inside_git_dir = 0;
 537         inside_work_tree = 1;
 538         if (offset == len)
 539                 return NULL;
 540
 541         /* Make "offset" point to past the '/', and add a '/' at the end */
 542         offset++;
 543         cwd[len++] = '/';
 544         cwd[len] = 0;
 545         return cwd + offset;
 546 }
 547
 548 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 549 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 550 {
 551         int root_len;
 552
 553         if (check_repository_format_gently(".", nongit_ok))
 554                 return NULL;
 555
 556         /* --work-tree is set without --git-dir; use discovered one */
 557         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 558                 const char *gitdir;
 559
 560                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 561                 if (chdir(cwd))
 562                         die_errno("Could not come back to cwd");
 563                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 564         }
 565
 566         inside_git_dir = 1;
 567         inside_work_tree = 0;
 568         if (offset != len) {
 569                 if (chdir(cwd))
 570                         die_errno("Cannot come back to cwd");
 571                 root_len = offset_1st_component(cwd);
 572                 cwd[offset > root_len ? offset : root_len] = '\0';
 573                 set_git_dir(cwd);
 574         }
 575         else
 576                 set_git_dir(".");
 577         return NULL;
 578 }
 579
 580 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 581 {
 582         if (!nongit_ok)
 583                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 584         if (chdir(cwd))
 585                 die_errno("Cannot come back to cwd");
 586         *nongit_ok = 1;
 587         return NULL;
 588 }
 589
 590 static dev_t get_device_or_die(const char *path, const char *prefix)
 591 {
 592         struct stat buf;
 593         if (stat(path, &buf))
 594                 die_errno("failed to stat '%s%s%s'",
 595                                 prefix ? prefix : "",
 596                                 prefix ? "/" : "", path);
 597         return buf.st_dev;
 598 }
 599
 600 /*
 601  * We cannot decide in this function whether we are in the work tree or
 602  * not, since the config can only be read _after_ this function was called.
 603  */
 604 static const char *setup_git_directory_gently_1(int *nongit_ok)
 605 {
 606         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 607         static char cwd[PATH_MAX+1];
 608         const char *gitdirenv, *ret;
 609         char *gitfile;
 610         int len, offset, ceil_offset;
 611         dev_t current_device = 0;
 612         int one_filesystem = 1;
 613
 614         /*
 615          * Let's assume that we are in a git repository.
 616          * If it turns out later that we are somewhere else, the value will be
 617          * updated accordingly.
 618          */
 619         if (nongit_ok)
 620                 *nongit_ok = 0;
 621
 622         if (!getcwd(cwd, sizeof(cwd)-1))
 623                 die_errno("Unable to read current working directory");
 624         offset = len = strlen(cwd);
 625
 626         /*
 627          * If GIT_DIR is set explicitly, we're not going
 628          * to do any discovery, but we still do repository
 629          * validation.
 630          */
 631         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 632         if (gitdirenv)
 633                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 634
 635         ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
 636         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 637                 ceil_offset = 1;
 638
 639         /*
 640          * Test in the following order (relative to the cwd):
 641          * - .git (file containing "gitdir: <path>")
 642          * - .git/
 643          * - ./ (bare)
 644          * - ../.git
 645          * - ../.git/
 646          * - ../ (bare)
 647          * - ../../.git/
 648          *   etc.
 649          */
 650         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 651         if (one_filesystem)
 652                 current_device = get_device_or_die(".", NULL);
 653         for (;;) {
 654                 gitfile = (char*)read_gitfile_gently(DEFAULT_GIT_DIR_ENVIRONMENT);
 655                 if (gitfile)
 656                         gitdirenv = gitfile = xstrdup(gitfile);
 657                 else {
 658                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 659                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 660                 }
 661
 662                 if (gitdirenv) {
 663                         ret = setup_discovered_git_dir(gitdirenv,
 664                                                        cwd, offset, len,
 665                                                        nongit_ok);
 666                         free(gitfile);
 667                         return ret;
 668                 }
 669                 free(gitfile);
 670
 671                 if (is_git_directory("."))
 672                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 673
 674                 while (--offset > ceil_offset && cwd[offset] != '/');
 675                 if (offset <= ceil_offset)
 676                         return setup_nongit(cwd, nongit_ok);
 677                 if (one_filesystem) {
 678                         dev_t parent_device = get_device_or_die("..", cwd);
 679                         if (parent_device != current_device) {
 680                                 if (nongit_ok) {
 681                                         if (chdir(cwd))
 682                                                 die_errno("Cannot come back to cwd");
 683                                         *nongit_ok = 1;
 684                                         return NULL;
 685                                 }
 686                                 cwd[offset] = '\0';
 687                                 die("Not a git repository (or any parent up to mount parent %s)\n"
 688                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 689                         }
 690                 }
 691                 if (chdir("..")) {
 692                         cwd[offset] = '\0';
 693                         die_errno("Cannot change to '%s/..'", cwd);
 694                 }
 695         }
 696 }
 697
 698 const char *setup_git_directory_gently(int *nongit_ok)
 699 {
 700         const char *prefix;
 701
 702         prefix = setup_git_directory_gently_1(nongit_ok);
 703         if (startup_info) {
 704                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 705                 startup_info->prefix = prefix;
 706         }
 707         return prefix;
 708 }
 709
 710 int git_config_perm(const char *var, const char *value)
 711 {
 712         int i;
 713         char *endptr;
 714
 715         if (value == NULL)
 716                 return PERM_GROUP;
 717
 718         if (!strcmp(value, "umask"))
 719                 return PERM_UMASK;
 720         if (!strcmp(value, "group"))
 721                 return PERM_GROUP;
 722         if (!strcmp(value, "all") ||
 723             !strcmp(value, "world") ||
 724             !strcmp(value, "everybody"))
 725                 return PERM_EVERYBODY;
 726
 727         /* Parse octal numbers */
 728         i = strtol(value, &endptr, 8);
 729
 730         /* If not an octal number, maybe true/false? */
 731         if (*endptr != 0)
 732                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 733
 734         /*
 735          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 736          * a chmod value to restrict to.
 737          */
 738         switch (i) {
 739         case PERM_UMASK:               /* 0 */
 740                 return PERM_UMASK;
 741         case OLD_PERM_GROUP:           /* 1 */
 742                 return PERM_GROUP;
 743         case OLD_PERM_EVERYBODY:       /* 2 */
 744                 return PERM_EVERYBODY;
 745         }
 746
 747         /* A filemode value was given: 0xxx */
 748
 749         if ((i & 0600) != 0600)
 750                 die("Problem with core.sharedRepository filemode value "
 751                     "(0%.3o).\nThe owner of files must always have "
 752                     "read and write permissions.", i);
 753
 754         /*
 755          * Mask filemode value. Others can not get write permission.
 756          * x flags for directories are handled separately.
 757          */
 758         return -(i & 0666);
 759 }
 760
 761 int check_repository_format_version(const char *var, const char *value, void *cb)
 762 {
 763         if (strcmp(var, "core.repositoryformatversion") == 0)
 764                 repository_format_version = git_config_int(var, value);
 765         else if (strcmp(var, "core.sharedrepository") == 0)
 766                 shared_repository = git_config_perm(var, value);
 767         else if (strcmp(var, "core.bare") == 0) {
 768                 is_bare_repository_cfg = git_config_bool(var, value);
 769                 if (is_bare_repository_cfg == 1)
 770                         inside_work_tree = -1;
 771         } else if (strcmp(var, "core.worktree") == 0) {
 772                 if (!value)
 773                         return config_error_nonbool(var);
 774                 free(git_work_tree_cfg);
 775                 git_work_tree_cfg = xstrdup(value);
 776                 inside_work_tree = -1;
 777         }
 778         return 0;
 779 }
 780
 781 int check_repository_format(void)
 782 {
 783         return check_repository_format_gently(get_git_dir(), NULL);
 784 }
 785
 786 /*
 787  * Returns the "prefix", a path to the current working directory
 788  * relative to the work tree root, or NULL, if the current working
 789  * directory is not a strict subdirectory of the work tree root. The
 790  * prefix always ends with a '/' character.
 791  */
 792 const char *setup_git_directory(void)
 793 {
 794         return setup_git_directory_gently(NULL);
 795 }