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
  89         /*
  90          * Saying "'(icase)foo' does not exist in the index" when the
  91          * user gave us ":(icase)foo" is just stupid.  A magic pathspec
  92          * begins with a colon and is followed by a non-alnum; do not
  93          * let get_sha1_with_mode_1(only_to_die=1) to even trigger.
  94          */
  95         if (!(arg[0] == ':' && !isalnum(arg[1])))
  96                 /* try a detailed diagnostic ... */
  97                 get_sha1_with_mode_1(arg, sha1, &mode, 1, prefix);
  98
  99         /* ... or fall back the most general message. */
 100         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 101             "Use '--' to separate paths from revisions", arg);
 102
 103 }
 104
 105 /*
 106  * Verify a filename that we got as an argument for a pathspec
 107  * entry. Note that a filename that begins with "-" never verifies
 108  * as true, because even if such a filename were to exist, we want
 109  * it to be preceded by the "--" marker (or we want the user to
 110  * use a format like "./-filename")
 111  */
 112 void verify_filename(const char *prefix, const char *arg)
 113 {
 114         if (*arg == '-')
 115                 die("bad flag '%s' used after filename", arg);
 116         if (check_filename(prefix, arg))
 117                 return;
 118         die_verify_filename(prefix, arg);
 119 }
 120
 121 /*
 122  * Opposite of the above: the command line did not have -- marker
 123  * and we parsed the arg as a refname.  It should not be interpretable
 124  * as a filename.
 125  */
 126 void verify_non_filename(const char *prefix, const char *arg)
 127 {
 128         if (!is_inside_work_tree() || is_inside_git_dir())
 129                 return;
 130         if (*arg == '-')
 131                 return; /* flag */
 132         if (!check_filename(prefix, arg))
 133                 return;
 134         die("ambiguous argument '%s': both revision and filename\n"
 135             "Use '--' to separate filenames from revisions", arg);
 136 }
 137
 138 /*
 139  * Magic pathspec
 140  *
 141  * NEEDSWORK: These need to be moved to dir.h or even to a new
 142  * pathspec.h when we restructure get_pathspec() users to use the
 143  * "struct pathspec" interface.
 144  *
 145  * Possible future magic semantics include stuff like:
 146  *
 147  *      { PATHSPEC_NOGLOB, '!', "noglob" },
 148  *      { PATHSPEC_ICASE, '\0', "icase" },
 149  *      { PATHSPEC_RECURSIVE, '*', "recursive" },
 150  *      { PATHSPEC_REGEXP, '\0', "regexp" },
 151  *
 152  */
 153 #define PATHSPEC_FROMTOP    (1<<0)
 154
 155 static struct pathspec_magic {
 156         unsigned bit;
 157         char mnemonic; /* this cannot be ':'! */
 158         const char *name;
 159 } pathspec_magic[] = {
 160         { PATHSPEC_FROMTOP, '/', "top" },
 161 };
 162
 163 /*
 164  * Take an element of a pathspec and check for magic signatures.
 165  * Append the result to the prefix.
 166  *
 167  * For now, we only parse the syntax and throw out anything other than
 168  * "top" magic.
 169  *
 170  * NEEDSWORK: This needs to be rewritten when we start migrating
 171  * get_pathspec() users to use the "struct pathspec" interface.  For
 172  * example, a pathspec element may be marked as case-insensitive, but
 173  * the prefix part must always match literally, and a single stupid
 174  * string cannot express such a case.
 175  */
 176 static const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
 177 {
 178         unsigned magic = 0;
 179         const char *copyfrom = elt;
 180         int i;
 181
 182         if (elt[0] != ':') {
 183                 ; /* nothing to do */
 184         } else if (elt[1] == '(') {
 185                 /* longhand */
 186                 const char *nextat;
 187                 for (copyfrom = elt + 2;
 188                      *copyfrom && *copyfrom != ')';
 189                      copyfrom = nextat) {
 190                         size_t len = strcspn(copyfrom, ",)");
 191                         if (copyfrom[len] == ')')
 192                                 nextat = copyfrom + len;
 193                         else
 194                                 nextat = copyfrom + len + 1;
 195                         if (!len)
 196                                 continue;
 197                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 198                                 if (strlen(pathspec_magic[i].name) == len &&
 199                                     !strncmp(pathspec_magic[i].name, copyfrom, len)) {
 200                                         magic |= pathspec_magic[i].bit;
 201                                         break;
 202                                 }
 203                         if (ARRAY_SIZE(pathspec_magic) <= i)
 204                                 die("Invalid pathspec magic '%.*s' in '%s'",
 205                                     (int) len, copyfrom, elt);
 206                 }
 207                 if (*copyfrom == ')')
 208                         copyfrom++;
 209         } else {
 210                 /* shorthand */
 211                 for (copyfrom = elt + 1;
 212                      *copyfrom && *copyfrom != ':';
 213                      copyfrom++) {
 214                         char ch = *copyfrom;
 215
 216                         if (!is_pathspec_magic(ch))
 217                                 break;
 218                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 219                                 if (pathspec_magic[i].mnemonic == ch) {
 220                                         magic |= pathspec_magic[i].bit;
 221                                         break;
 222                                 }
 223                         if (ARRAY_SIZE(pathspec_magic) <= i)
 224                                 die("Unimplemented pathspec magic '%c' in '%s'",
 225                                     ch, elt);
 226                 }
 227                 if (*copyfrom == ':')
 228                         copyfrom++;
 229         }
 230
 231         if (magic & PATHSPEC_FROMTOP)
 232                 return xstrdup(copyfrom);
 233         else
 234                 return prefix_path(prefix, prefixlen, copyfrom);
 235 }
 236
 237 const char **get_pathspec(const char *prefix, const char **pathspec)
 238 {
 239         const char *entry = *pathspec;
 240         const char **src, **dst;
 241         int prefixlen;
 242
 243         if (!prefix && !entry)
 244                 return NULL;
 245
 246         if (!entry) {
 247                 static const char *spec[2];
 248                 spec[0] = prefix;
 249                 spec[1] = NULL;
 250                 return spec;
 251         }
 252
 253         /* Otherwise we have to re-write the entries.. */
 254         src = pathspec;
 255         dst = pathspec;
 256         prefixlen = prefix ? strlen(prefix) : 0;
 257         while (*src) {
 258                 *(dst++) = prefix_pathspec(prefix, prefixlen, *src);
 259                 src++;
 260         }
 261         *dst = NULL;
 262         if (!*pathspec)
 263                 return NULL;
 264         return pathspec;
 265 }
 266
 267 /*
 268  * Test if it looks like we're at a git directory.
 269  * We want to see:
 270  *
 271  *  - either an objects/ directory _or_ the proper
 272  *    GIT_OBJECT_DIRECTORY environment variable
 273  *  - a refs/ directory
 274  *  - either a HEAD symlink or a HEAD file that is formatted as
 275  *    a proper "ref:", or a regular file HEAD that has a properly
 276  *    formatted sha1 object name.
 277  */
 278 static int is_git_directory(const char *suspect)
 279 {
 280         char path[PATH_MAX];
 281         size_t len = strlen(suspect);
 282
 283         if (PATH_MAX <= len + strlen("/objects"))
 284                 die("Too long path: %.*s", 60, suspect);
 285         strcpy(path, suspect);
 286         if (getenv(DB_ENVIRONMENT)) {
 287                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 288                         return 0;
 289         }
 290         else {
 291                 strcpy(path + len, "/objects");
 292                 if (access(path, X_OK))
 293                         return 0;
 294         }
 295
 296         strcpy(path + len, "/refs");
 297         if (access(path, X_OK))
 298                 return 0;
 299
 300         strcpy(path + len, "/HEAD");
 301         if (validate_headref(path))
 302                 return 0;
 303
 304         return 1;
 305 }
 306
 307 int is_inside_git_dir(void)
 308 {
 309         if (inside_git_dir < 0)
 310                 inside_git_dir = is_inside_dir(get_git_dir());
 311         return inside_git_dir;
 312 }
 313
 314 int is_inside_work_tree(void)
 315 {
 316         if (inside_work_tree < 0)
 317                 inside_work_tree = is_inside_dir(get_git_work_tree());
 318         return inside_work_tree;
 319 }
 320
 321 void setup_work_tree(void)
 322 {
 323         const char *work_tree, *git_dir;
 324         static int initialized = 0;
 325
 326         if (initialized)
 327                 return;
 328         work_tree = get_git_work_tree();
 329         git_dir = get_git_dir();
 330         if (!is_absolute_path(git_dir))
 331                 git_dir = real_path(get_git_dir());
 332         if (!work_tree || chdir(work_tree))
 333                 die("This operation must be run in a work tree");
 334
 335         /*
 336          * Make sure subsequent git processes find correct worktree
 337          * if $GIT_WORK_TREE is set relative
 338          */
 339         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 340                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 341
 342         set_git_dir(relative_path(git_dir, work_tree));
 343         initialized = 1;
 344 }
 345
 346 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 347 {
 348         char repo_config[PATH_MAX+1];
 349
 350         /*
 351          * git_config() can't be used here because it calls git_pathdup()
 352          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 353          * set git_dir to ".git".
 354          *
 355          * We are in gitdir setup, no git dir has been found useable yet.
 356          * Use a gentler version of git_config() to check if this repo
 357          * is a good one.
 358          */
 359         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 360         git_config_early(check_repository_format_version, NULL, repo_config);
 361         if (GIT_REPO_VERSION < repository_format_version) {
 362                 if (!nongit_ok)
 363                         die ("Expected git repo version <= %d, found %d",
 364                              GIT_REPO_VERSION, repository_format_version);
 365                 warning("Expected git repo version <= %d, found %d",
 366                         GIT_REPO_VERSION, repository_format_version);
 367                 warning("Please upgrade Git");
 368                 *nongit_ok = -1;
 369                 return -1;
 370         }
 371         return 0;
 372 }
 373
 374 /*
 375  * Try to read the location of the git directory from the .git file,
 376  * return path to git directory if found.
 377  */
 378 const char *read_gitfile_gently(const char *path)
 379 {
 380         char *buf;
 381         char *dir;
 382         const char *slash;
 383         struct stat st;
 384         int fd;
 385         ssize_t len;
 386
 387         if (stat(path, &st))
 388                 return NULL;
 389         if (!S_ISREG(st.st_mode))
 390                 return NULL;
 391         fd = open(path, O_RDONLY);
 392         if (fd < 0)
 393                 die_errno("Error opening '%s'", path);
 394         buf = xmalloc(st.st_size + 1);
 395         len = read_in_full(fd, buf, st.st_size);
 396         close(fd);
 397         if (len != st.st_size)
 398                 die("Error reading %s", path);
 399         buf[len] = '\0';
 400         if (prefixcmp(buf, "gitdir: "))
 401                 die("Invalid gitfile format: %s", path);
 402         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 403                 len--;
 404         if (len < 9)
 405                 die("No path in gitfile: %s", path);
 406         buf[len] = '\0';
 407         dir = buf + 8;
 408
 409         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 410                 size_t pathlen = slash+1 - path;
 411                 size_t dirlen = pathlen + len - 8;
 412                 dir = xmalloc(dirlen + 1);
 413                 strncpy(dir, path, pathlen);
 414                 strncpy(dir + pathlen, buf + 8, len - 8);
 415                 dir[dirlen] = '\0';
 416                 free(buf);
 417                 buf = dir;
 418         }
 419
 420         if (!is_git_directory(dir))
 421                 die("Not a git repository: %s", dir);
 422         path = real_path(dir);
 423
 424         free(buf);
 425         return path;
 426 }
 427
 428 static const char *setup_explicit_git_dir(const char *gitdirenv,
 429                                           char *cwd, int len,
 430                                           int *nongit_ok)
 431 {
 432         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 433         const char *worktree;
 434         char *gitfile;
 435         int offset;
 436
 437         if (PATH_MAX - 40 < strlen(gitdirenv))
 438                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 439
 440         gitfile = (char*)read_gitfile_gently(gitdirenv);
 441         if (gitfile) {
 442                 gitfile = xstrdup(gitfile);
 443                 gitdirenv = gitfile;
 444         }
 445
 446         if (!is_git_directory(gitdirenv)) {
 447                 if (nongit_ok) {
 448                         *nongit_ok = 1;
 449                         free(gitfile);
 450                         return NULL;
 451                 }
 452                 die("Not a git repository: '%s'", gitdirenv);
 453         }
 454
 455         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 456                 free(gitfile);
 457                 return NULL;
 458         }
 459
 460         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 461         if (work_tree_env)
 462                 set_git_work_tree(work_tree_env);
 463         else if (is_bare_repository_cfg > 0) {
 464                 if (git_work_tree_cfg) /* #22.2, #30 */
 465                         die("core.bare and core.worktree do not make sense");
 466
 467                 /* #18, #26 */
 468                 set_git_dir(gitdirenv);
 469                 free(gitfile);
 470                 return NULL;
 471         }
 472         else if (git_work_tree_cfg) { /* #6, #14 */
 473                 if (is_absolute_path(git_work_tree_cfg))
 474                         set_git_work_tree(git_work_tree_cfg);
 475                 else {
 476                         char core_worktree[PATH_MAX];
 477                         if (chdir(gitdirenv))
 478                                 die_errno("Could not chdir to '%s'", gitdirenv);
 479                         if (chdir(git_work_tree_cfg))
 480                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 481                         if (!getcwd(core_worktree, PATH_MAX))
 482                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 483                         if (chdir(cwd))
 484                                 die_errno("Could not come back to cwd");
 485                         set_git_work_tree(core_worktree);
 486                 }
 487         }
 488         else /* #2, #10 */
 489                 set_git_work_tree(".");
 490
 491         /* set_git_work_tree() must have been called by now */
 492         worktree = get_git_work_tree();
 493
 494         /* both get_git_work_tree() and cwd are already normalized */
 495         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 496                 set_git_dir(gitdirenv);
 497                 free(gitfile);
 498                 return NULL;
 499         }
 500
 501         offset = dir_inside_of(cwd, worktree);
 502         if (offset >= 0) {      /* cwd inside worktree? */
 503                 set_git_dir(real_path(gitdirenv));
 504                 if (chdir(worktree))
 505                         die_errno("Could not chdir to '%s'", worktree);
 506                 cwd[len++] = '/';
 507                 cwd[len] = '\0';
 508                 free(gitfile);
 509                 return cwd + offset;
 510         }
 511
 512         /* cwd outside worktree */
 513         set_git_dir(gitdirenv);
 514         free(gitfile);
 515         return NULL;
 516 }
 517
 518 static const char *setup_discovered_git_dir(const char *gitdir,
 519                                             char *cwd, int offset, int len,
 520                                             int *nongit_ok)
 521 {
 522         if (check_repository_format_gently(gitdir, nongit_ok))
 523                 return NULL;
 524
 525         /* --work-tree is set without --git-dir; use discovered one */
 526         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 527                 if (offset != len && !is_absolute_path(gitdir))
 528                         gitdir = xstrdup(real_path(gitdir));
 529                 if (chdir(cwd))
 530                         die_errno("Could not come back to cwd");
 531                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 532         }
 533
 534         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 535         if (is_bare_repository_cfg > 0) {
 536                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 537                 if (chdir(cwd))
 538                         die_errno("Could not come back to cwd");
 539                 return NULL;
 540         }
 541
 542         /* #0, #1, #5, #8, #9, #12, #13 */
 543         set_git_work_tree(".");
 544         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 545                 set_git_dir(gitdir);
 546         inside_git_dir = 0;
 547         inside_work_tree = 1;
 548         if (offset == len)
 549                 return NULL;
 550
 551         /* Make "offset" point to past the '/', and add a '/' at the end */
 552         offset++;
 553         cwd[len++] = '/';
 554         cwd[len] = 0;
 555         return cwd + offset;
 556 }
 557
 558 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 559 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 560 {
 561         int root_len;
 562
 563         if (check_repository_format_gently(".", nongit_ok))
 564                 return NULL;
 565
 566         /* --work-tree is set without --git-dir; use discovered one */
 567         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 568                 const char *gitdir;
 569
 570                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 571                 if (chdir(cwd))
 572                         die_errno("Could not come back to cwd");
 573                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 574         }
 575
 576         inside_git_dir = 1;
 577         inside_work_tree = 0;
 578         if (offset != len) {
 579                 if (chdir(cwd))
 580                         die_errno("Cannot come back to cwd");
 581                 root_len = offset_1st_component(cwd);
 582                 cwd[offset > root_len ? offset : root_len] = '\0';
 583                 set_git_dir(cwd);
 584         }
 585         else
 586                 set_git_dir(".");
 587         return NULL;
 588 }
 589
 590 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 591 {
 592         if (!nongit_ok)
 593                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 594         if (chdir(cwd))
 595                 die_errno("Cannot come back to cwd");
 596         *nongit_ok = 1;
 597         return NULL;
 598 }
 599
 600 static dev_t get_device_or_die(const char *path, const char *prefix)
 601 {
 602         struct stat buf;
 603         if (stat(path, &buf))
 604                 die_errno("failed to stat '%s%s%s'",
 605                                 prefix ? prefix : "",
 606                                 prefix ? "/" : "", path);
 607         return buf.st_dev;
 608 }
 609
 610 /*
 611  * We cannot decide in this function whether we are in the work tree or
 612  * not, since the config can only be read _after_ this function was called.
 613  */
 614 static const char *setup_git_directory_gently_1(int *nongit_ok)
 615 {
 616         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 617         static char cwd[PATH_MAX+1];
 618         const char *gitdirenv, *ret;
 619         char *gitfile;
 620         int len, offset, ceil_offset;
 621         dev_t current_device = 0;
 622         int one_filesystem = 1;
 623
 624         /*
 625          * Let's assume that we are in a git repository.
 626          * If it turns out later that we are somewhere else, the value will be
 627          * updated accordingly.
 628          */
 629         if (nongit_ok)
 630                 *nongit_ok = 0;
 631
 632         if (!getcwd(cwd, sizeof(cwd)-1))
 633                 die_errno("Unable to read current working directory");
 634         offset = len = strlen(cwd);
 635
 636         /*
 637          * If GIT_DIR is set explicitly, we're not going
 638          * to do any discovery, but we still do repository
 639          * validation.
 640          */
 641         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 642         if (gitdirenv)
 643                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 644
 645         ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
 646         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 647                 ceil_offset = 1;
 648
 649         /*
 650          * Test in the following order (relative to the cwd):
 651          * - .git (file containing "gitdir: <path>")
 652          * - .git/
 653          * - ./ (bare)
 654          * - ../.git
 655          * - ../.git/
 656          * - ../ (bare)
 657          * - ../../.git/
 658          *   etc.
 659          */
 660         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 661         if (one_filesystem)
 662                 current_device = get_device_or_die(".", NULL);
 663         for (;;) {
 664                 gitfile = (char*)read_gitfile_gently(DEFAULT_GIT_DIR_ENVIRONMENT);
 665                 if (gitfile)
 666                         gitdirenv = gitfile = xstrdup(gitfile);
 667                 else {
 668                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 669                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 670                 }
 671
 672                 if (gitdirenv) {
 673                         ret = setup_discovered_git_dir(gitdirenv,
 674                                                        cwd, offset, len,
 675                                                        nongit_ok);
 676                         free(gitfile);
 677                         return ret;
 678                 }
 679                 free(gitfile);
 680
 681                 if (is_git_directory("."))
 682                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 683
 684                 while (--offset > ceil_offset && cwd[offset] != '/');
 685                 if (offset <= ceil_offset)
 686                         return setup_nongit(cwd, nongit_ok);
 687                 if (one_filesystem) {
 688                         dev_t parent_device = get_device_or_die("..", cwd);
 689                         if (parent_device != current_device) {
 690                                 if (nongit_ok) {
 691                                         if (chdir(cwd))
 692                                                 die_errno("Cannot come back to cwd");
 693                                         *nongit_ok = 1;
 694                                         return NULL;
 695                                 }
 696                                 cwd[offset] = '\0';
 697                                 die("Not a git repository (or any parent up to mount parent %s)\n"
 698                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 699                         }
 700                 }
 701                 if (chdir("..")) {
 702                         cwd[offset] = '\0';
 703                         die_errno("Cannot change to '%s/..'", cwd);
 704                 }
 705         }
 706 }
 707
 708 const char *setup_git_directory_gently(int *nongit_ok)
 709 {
 710         const char *prefix;
 711
 712         prefix = setup_git_directory_gently_1(nongit_ok);
 713         if (prefix)
 714                 setenv("GIT_PREFIX", prefix, 1);
 715         else
 716                 setenv("GIT_PREFIX", "", 1);
 717
 718         if (startup_info) {
 719                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 720                 startup_info->prefix = prefix;
 721         }
 722         return prefix;
 723 }
 724
 725 int git_config_perm(const char *var, const char *value)
 726 {
 727         int i;
 728         char *endptr;
 729
 730         if (value == NULL)
 731                 return PERM_GROUP;
 732
 733         if (!strcmp(value, "umask"))
 734                 return PERM_UMASK;
 735         if (!strcmp(value, "group"))
 736                 return PERM_GROUP;
 737         if (!strcmp(value, "all") ||
 738             !strcmp(value, "world") ||
 739             !strcmp(value, "everybody"))
 740                 return PERM_EVERYBODY;
 741
 742         /* Parse octal numbers */
 743         i = strtol(value, &endptr, 8);
 744
 745         /* If not an octal number, maybe true/false? */
 746         if (*endptr != 0)
 747                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 748
 749         /*
 750          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 751          * a chmod value to restrict to.
 752          */
 753         switch (i) {
 754         case PERM_UMASK:               /* 0 */
 755                 return PERM_UMASK;
 756         case OLD_PERM_GROUP:           /* 1 */
 757                 return PERM_GROUP;
 758         case OLD_PERM_EVERYBODY:       /* 2 */
 759                 return PERM_EVERYBODY;
 760         }
 761
 762         /* A filemode value was given: 0xxx */
 763
 764         if ((i & 0600) != 0600)
 765                 die("Problem with core.sharedRepository filemode value "
 766                     "(0%.3o).\nThe owner of files must always have "
 767                     "read and write permissions.", i);
 768
 769         /*
 770          * Mask filemode value. Others can not get write permission.
 771          * x flags for directories are handled separately.
 772          */
 773         return -(i & 0666);
 774 }
 775
 776 int check_repository_format_version(const char *var, const char *value, void *cb)
 777 {
 778         if (strcmp(var, "core.repositoryformatversion") == 0)
 779                 repository_format_version = git_config_int(var, value);
 780         else if (strcmp(var, "core.sharedrepository") == 0)
 781                 shared_repository = git_config_perm(var, value);
 782         else if (strcmp(var, "core.bare") == 0) {
 783                 is_bare_repository_cfg = git_config_bool(var, value);
 784                 if (is_bare_repository_cfg == 1)
 785                         inside_work_tree = -1;
 786         } else if (strcmp(var, "core.worktree") == 0) {
 787                 if (!value)
 788                         return config_error_nonbool(var);
 789                 free(git_work_tree_cfg);
 790                 git_work_tree_cfg = xstrdup(value);
 791                 inside_work_tree = -1;
 792         }
 793         return 0;
 794 }
 795
 796 int check_repository_format(void)
 797 {
 798         return check_repository_format_gently(get_git_dir(), NULL);
 799 }
 800
 801 /*
 802  * Returns the "prefix", a path to the current working directory
 803  * relative to the work tree root, or NULL, if the current working
 804  * directory is not a strict subdirectory of the work tree root. The
 805  * prefix always ends with a '/' character.
 806  */
 807 const char *setup_git_directory(void)
 808 {
 809         return setup_git_directory_gently(NULL);
 810 }