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 const char *pathspec_prefix(const char *prefix, const char **pathspec)
 240 {
 241         const char **p, *n, *prev;
 242         unsigned long max;
 243
 244         if (!pathspec)
 245                 return prefix ? xmemdupz(prefix, strlen(prefix)) : NULL;
 246
 247         prev = NULL;
 248         max = PATH_MAX;
 249         for (p = pathspec; (n = *p) != NULL; p++) {
 250                 int i, len = 0;
 251                 for (i = 0; i < max; i++) {
 252                         char c = n[i];
 253                         if (prev && prev[i] != c)
 254                                 break;
 255                         if (!c || c == '*' || c == '?')
 256                                 break;
 257                         if (c == '/')
 258                                 len = i+1;
 259                 }
 260                 prev = n;
 261                 if (len < max) {
 262                         max = len;
 263                         if (!max)
 264                                 break;
 265                 }
 266         }
 267
 268         return max ? xmemdupz(prev, max) : NULL;
 269 }
 270
 271 /*
 272  * Test if it looks like we're at a git directory.
 273  * We want to see:
 274  *
 275  *  - either an objects/ directory _or_ the proper
 276  *    GIT_OBJECT_DIRECTORY environment variable
 277  *  - a refs/ directory
 278  *  - either a HEAD symlink or a HEAD file that is formatted as
 279  *    a proper "ref:", or a regular file HEAD that has a properly
 280  *    formatted sha1 object name.
 281  */
 282 static int is_git_directory(const char *suspect)
 283 {
 284         char path[PATH_MAX];
 285         size_t len = strlen(suspect);
 286
 287         if (PATH_MAX <= len + strlen("/objects"))
 288                 die("Too long path: %.*s", 60, suspect);
 289         strcpy(path, suspect);
 290         if (getenv(DB_ENVIRONMENT)) {
 291                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 292                         return 0;
 293         }
 294         else {
 295                 strcpy(path + len, "/objects");
 296                 if (access(path, X_OK))
 297                         return 0;
 298         }
 299
 300         strcpy(path + len, "/refs");
 301         if (access(path, X_OK))
 302                 return 0;
 303
 304         strcpy(path + len, "/HEAD");
 305         if (validate_headref(path))
 306                 return 0;
 307
 308         return 1;
 309 }
 310
 311 int is_inside_git_dir(void)
 312 {
 313         if (inside_git_dir < 0)
 314                 inside_git_dir = is_inside_dir(get_git_dir());
 315         return inside_git_dir;
 316 }
 317
 318 int is_inside_work_tree(void)
 319 {
 320         if (inside_work_tree < 0)
 321                 inside_work_tree = is_inside_dir(get_git_work_tree());
 322         return inside_work_tree;
 323 }
 324
 325 void setup_work_tree(void)
 326 {
 327         const char *work_tree, *git_dir;
 328         static int initialized = 0;
 329
 330         if (initialized)
 331                 return;
 332         work_tree = get_git_work_tree();
 333         git_dir = get_git_dir();
 334         if (!is_absolute_path(git_dir))
 335                 git_dir = real_path(get_git_dir());
 336         if (!work_tree || chdir(work_tree))
 337                 die("This operation must be run in a work tree");
 338
 339         /*
 340          * Make sure subsequent git processes find correct worktree
 341          * if $GIT_WORK_TREE is set relative
 342          */
 343         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 344                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 345
 346         set_git_dir(relative_path(git_dir, work_tree));
 347         initialized = 1;
 348 }
 349
 350 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 351 {
 352         char repo_config[PATH_MAX+1];
 353
 354         /*
 355          * git_config() can't be used here because it calls git_pathdup()
 356          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 357          * set git_dir to ".git".
 358          *
 359          * We are in gitdir setup, no git dir has been found useable yet.
 360          * Use a gentler version of git_config() to check if this repo
 361          * is a good one.
 362          */
 363         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 364         git_config_early(check_repository_format_version, NULL, repo_config);
 365         if (GIT_REPO_VERSION < repository_format_version) {
 366                 if (!nongit_ok)
 367                         die ("Expected git repo version <= %d, found %d",
 368                              GIT_REPO_VERSION, repository_format_version);
 369                 warning("Expected git repo version <= %d, found %d",
 370                         GIT_REPO_VERSION, repository_format_version);
 371                 warning("Please upgrade Git");
 372                 *nongit_ok = -1;
 373                 return -1;
 374         }
 375         return 0;
 376 }
 377
 378 /*
 379  * Try to read the location of the git directory from the .git file,
 380  * return path to git directory if found.
 381  */
 382 const char *read_gitfile(const char *path)
 383 {
 384         char *buf;
 385         char *dir;
 386         const char *slash;
 387         struct stat st;
 388         int fd;
 389         ssize_t len;
 390
 391         if (stat(path, &st))
 392                 return NULL;
 393         if (!S_ISREG(st.st_mode))
 394                 return NULL;
 395         fd = open(path, O_RDONLY);
 396         if (fd < 0)
 397                 die_errno("Error opening '%s'", path);
 398         buf = xmalloc(st.st_size + 1);
 399         len = read_in_full(fd, buf, st.st_size);
 400         close(fd);
 401         if (len != st.st_size)
 402                 die("Error reading %s", path);
 403         buf[len] = '\0';
 404         if (prefixcmp(buf, "gitdir: "))
 405                 die("Invalid gitfile format: %s", path);
 406         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 407                 len--;
 408         if (len < 9)
 409                 die("No path in gitfile: %s", path);
 410         buf[len] = '\0';
 411         dir = buf + 8;
 412
 413         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 414                 size_t pathlen = slash+1 - path;
 415                 size_t dirlen = pathlen + len - 8;
 416                 dir = xmalloc(dirlen + 1);
 417                 strncpy(dir, path, pathlen);
 418                 strncpy(dir + pathlen, buf + 8, len - 8);
 419                 dir[dirlen] = '\0';
 420                 free(buf);
 421                 buf = dir;
 422         }
 423
 424         if (!is_git_directory(dir))
 425                 die("Not a git repository: %s", dir);
 426         path = real_path(dir);
 427
 428         free(buf);
 429         return path;
 430 }
 431
 432 static const char *setup_explicit_git_dir(const char *gitdirenv,
 433                                           char *cwd, int len,
 434                                           int *nongit_ok)
 435 {
 436         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 437         const char *worktree;
 438         char *gitfile;
 439         int offset;
 440
 441         if (PATH_MAX - 40 < strlen(gitdirenv))
 442                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 443
 444         gitfile = (char*)read_gitfile(gitdirenv);
 445         if (gitfile) {
 446                 gitfile = xstrdup(gitfile);
 447                 gitdirenv = gitfile;
 448         }
 449
 450         if (!is_git_directory(gitdirenv)) {
 451                 if (nongit_ok) {
 452                         *nongit_ok = 1;
 453                         free(gitfile);
 454                         return NULL;
 455                 }
 456                 die("Not a git repository: '%s'", gitdirenv);
 457         }
 458
 459         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 460                 free(gitfile);
 461                 return NULL;
 462         }
 463
 464         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 465         if (work_tree_env)
 466                 set_git_work_tree(work_tree_env);
 467         else if (is_bare_repository_cfg > 0) {
 468                 if (git_work_tree_cfg) /* #22.2, #30 */
 469                         die("core.bare and core.worktree do not make sense");
 470
 471                 /* #18, #26 */
 472                 set_git_dir(gitdirenv);
 473                 free(gitfile);
 474                 return NULL;
 475         }
 476         else if (git_work_tree_cfg) { /* #6, #14 */
 477                 if (is_absolute_path(git_work_tree_cfg))
 478                         set_git_work_tree(git_work_tree_cfg);
 479                 else {
 480                         char core_worktree[PATH_MAX];
 481                         if (chdir(gitdirenv))
 482                                 die_errno("Could not chdir to '%s'", gitdirenv);
 483                         if (chdir(git_work_tree_cfg))
 484                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 485                         if (!getcwd(core_worktree, PATH_MAX))
 486                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 487                         if (chdir(cwd))
 488                                 die_errno("Could not come back to cwd");
 489                         set_git_work_tree(core_worktree);
 490                 }
 491         }
 492         else /* #2, #10 */
 493                 set_git_work_tree(".");
 494
 495         /* set_git_work_tree() must have been called by now */
 496         worktree = get_git_work_tree();
 497
 498         /* both get_git_work_tree() and cwd are already normalized */
 499         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 500                 set_git_dir(gitdirenv);
 501                 free(gitfile);
 502                 return NULL;
 503         }
 504
 505         offset = dir_inside_of(cwd, worktree);
 506         if (offset >= 0) {      /* cwd inside worktree? */
 507                 set_git_dir(real_path(gitdirenv));
 508                 if (chdir(worktree))
 509                         die_errno("Could not chdir to '%s'", worktree);
 510                 cwd[len++] = '/';
 511                 cwd[len] = '\0';
 512                 free(gitfile);
 513                 return cwd + offset;
 514         }
 515
 516         /* cwd outside worktree */
 517         set_git_dir(gitdirenv);
 518         free(gitfile);
 519         return NULL;
 520 }
 521
 522 static const char *setup_discovered_git_dir(const char *gitdir,
 523                                             char *cwd, int offset, int len,
 524                                             int *nongit_ok)
 525 {
 526         if (check_repository_format_gently(gitdir, nongit_ok))
 527                 return NULL;
 528
 529         /* --work-tree is set without --git-dir; use discovered one */
 530         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 531                 if (offset != len && !is_absolute_path(gitdir))
 532                         gitdir = xstrdup(real_path(gitdir));
 533                 if (chdir(cwd))
 534                         die_errno("Could not come back to cwd");
 535                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 536         }
 537
 538         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 539         if (is_bare_repository_cfg > 0) {
 540                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 541                 if (chdir(cwd))
 542                         die_errno("Could not come back to cwd");
 543                 return NULL;
 544         }
 545
 546         /* #0, #1, #5, #8, #9, #12, #13 */
 547         set_git_work_tree(".");
 548         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 549                 set_git_dir(gitdir);
 550         inside_git_dir = 0;
 551         inside_work_tree = 1;
 552         if (offset == len)
 553                 return NULL;
 554
 555         /* Make "offset" point to past the '/', and add a '/' at the end */
 556         offset++;
 557         cwd[len++] = '/';
 558         cwd[len] = 0;
 559         return cwd + offset;
 560 }
 561
 562 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 563 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 564 {
 565         int root_len;
 566
 567         if (check_repository_format_gently(".", nongit_ok))
 568                 return NULL;
 569
 570         /* --work-tree is set without --git-dir; use discovered one */
 571         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 572                 const char *gitdir;
 573
 574                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 575                 if (chdir(cwd))
 576                         die_errno("Could not come back to cwd");
 577                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 578         }
 579
 580         inside_git_dir = 1;
 581         inside_work_tree = 0;
 582         if (offset != len) {
 583                 if (chdir(cwd))
 584                         die_errno("Cannot come back to cwd");
 585                 root_len = offset_1st_component(cwd);
 586                 cwd[offset > root_len ? offset : root_len] = '\0';
 587                 set_git_dir(cwd);
 588         }
 589         else
 590                 set_git_dir(".");
 591         return NULL;
 592 }
 593
 594 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 595 {
 596         if (!nongit_ok)
 597                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 598         if (chdir(cwd))
 599                 die_errno("Cannot come back to cwd");
 600         *nongit_ok = 1;
 601         return NULL;
 602 }
 603
 604 static dev_t get_device_or_die(const char *path, const char *prefix)
 605 {
 606         struct stat buf;
 607         if (stat(path, &buf))
 608                 die_errno("failed to stat '%s%s%s'",
 609                                 prefix ? prefix : "",
 610                                 prefix ? "/" : "", path);
 611         return buf.st_dev;
 612 }
 613
 614 /*
 615  * We cannot decide in this function whether we are in the work tree or
 616  * not, since the config can only be read _after_ this function was called.
 617  */
 618 static const char *setup_git_directory_gently_1(int *nongit_ok)
 619 {
 620         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 621         static char cwd[PATH_MAX+1];
 622         const char *gitdirenv, *ret;
 623         char *gitfile;
 624         int len, offset, ceil_offset;
 625         dev_t current_device = 0;
 626         int one_filesystem = 1;
 627
 628         /*
 629          * Let's assume that we are in a git repository.
 630          * If it turns out later that we are somewhere else, the value will be
 631          * updated accordingly.
 632          */
 633         if (nongit_ok)
 634                 *nongit_ok = 0;
 635
 636         if (!getcwd(cwd, sizeof(cwd)-1))
 637                 die_errno("Unable to read current working directory");
 638         offset = len = strlen(cwd);
 639
 640         /*
 641          * If GIT_DIR is set explicitly, we're not going
 642          * to do any discovery, but we still do repository
 643          * validation.
 644          */
 645         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 646         if (gitdirenv)
 647                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 648
 649         ceil_offset = longest_ancestor_length(cwd, env_ceiling_dirs);
 650         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 651                 ceil_offset = 1;
 652
 653         /*
 654          * Test in the following order (relative to the cwd):
 655          * - .git (file containing "gitdir: <path>")
 656          * - .git/
 657          * - ./ (bare)
 658          * - ../.git
 659          * - ../.git/
 660          * - ../ (bare)
 661          * - ../../.git/
 662          *   etc.
 663          */
 664         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 665         if (one_filesystem)
 666                 current_device = get_device_or_die(".", NULL);
 667         for (;;) {
 668                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 669                 if (gitfile)
 670                         gitdirenv = gitfile = xstrdup(gitfile);
 671                 else {
 672                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 673                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 674                 }
 675
 676                 if (gitdirenv) {
 677                         ret = setup_discovered_git_dir(gitdirenv,
 678                                                        cwd, offset, len,
 679                                                        nongit_ok);
 680                         free(gitfile);
 681                         return ret;
 682                 }
 683                 free(gitfile);
 684
 685                 if (is_git_directory("."))
 686                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 687
 688                 while (--offset > ceil_offset && cwd[offset] != '/');
 689                 if (offset <= ceil_offset)
 690                         return setup_nongit(cwd, nongit_ok);
 691                 if (one_filesystem) {
 692                         dev_t parent_device = get_device_or_die("..", cwd);
 693                         if (parent_device != current_device) {
 694                                 if (nongit_ok) {
 695                                         if (chdir(cwd))
 696                                                 die_errno("Cannot come back to cwd");
 697                                         *nongit_ok = 1;
 698                                         return NULL;
 699                                 }
 700                                 cwd[offset] = '\0';
 701                                 die("Not a git repository (or any parent up to mount parent %s)\n"
 702                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 703                         }
 704                 }
 705                 if (chdir("..")) {
 706                         cwd[offset] = '\0';
 707                         die_errno("Cannot change to '%s/..'", cwd);
 708                 }
 709         }
 710 }
 711
 712 const char *setup_git_directory_gently(int *nongit_ok)
 713 {
 714         const char *prefix;
 715
 716         prefix = setup_git_directory_gently_1(nongit_ok);
 717         if (prefix)
 718                 setenv("GIT_PREFIX", prefix, 1);
 719         else
 720                 setenv("GIT_PREFIX", "", 1);
 721
 722         if (startup_info) {
 723                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 724                 startup_info->prefix = prefix;
 725         }
 726         return prefix;
 727 }
 728
 729 int git_config_perm(const char *var, const char *value)
 730 {
 731         int i;
 732         char *endptr;
 733
 734         if (value == NULL)
 735                 return PERM_GROUP;
 736
 737         if (!strcmp(value, "umask"))
 738                 return PERM_UMASK;
 739         if (!strcmp(value, "group"))
 740                 return PERM_GROUP;
 741         if (!strcmp(value, "all") ||
 742             !strcmp(value, "world") ||
 743             !strcmp(value, "everybody"))
 744                 return PERM_EVERYBODY;
 745
 746         /* Parse octal numbers */
 747         i = strtol(value, &endptr, 8);
 748
 749         /* If not an octal number, maybe true/false? */
 750         if (*endptr != 0)
 751                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 752
 753         /*
 754          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 755          * a chmod value to restrict to.
 756          */
 757         switch (i) {
 758         case PERM_UMASK:               /* 0 */
 759                 return PERM_UMASK;
 760         case OLD_PERM_GROUP:           /* 1 */
 761                 return PERM_GROUP;
 762         case OLD_PERM_EVERYBODY:       /* 2 */
 763                 return PERM_EVERYBODY;
 764         }
 765
 766         /* A filemode value was given: 0xxx */
 767
 768         if ((i & 0600) != 0600)
 769                 die("Problem with core.sharedRepository filemode value "
 770                     "(0%.3o).\nThe owner of files must always have "
 771                     "read and write permissions.", i);
 772
 773         /*
 774          * Mask filemode value. Others can not get write permission.
 775          * x flags for directories are handled separately.
 776          */
 777         return -(i & 0666);
 778 }
 779
 780 int check_repository_format_version(const char *var, const char *value, void *cb)
 781 {
 782         if (strcmp(var, "core.repositoryformatversion") == 0)
 783                 repository_format_version = git_config_int(var, value);
 784         else if (strcmp(var, "core.sharedrepository") == 0)
 785                 shared_repository = git_config_perm(var, value);
 786         else if (strcmp(var, "core.bare") == 0) {
 787                 is_bare_repository_cfg = git_config_bool(var, value);
 788                 if (is_bare_repository_cfg == 1)
 789                         inside_work_tree = -1;
 790         } else if (strcmp(var, "core.worktree") == 0) {
 791                 if (!value)
 792                         return config_error_nonbool(var);
 793                 free(git_work_tree_cfg);
 794                 git_work_tree_cfg = xstrdup(value);
 795                 inside_work_tree = -1;
 796         }
 797         return 0;
 798 }
 799
 800 int check_repository_format(void)
 801 {
 802         return check_repository_format_gently(get_git_dir(), NULL);
 803 }
 804
 805 /*
 806  * Returns the "prefix", a path to the current working directory
 807  * relative to the work tree root, or NULL, if the current working
 808  * directory is not a strict subdirectory of the work tree root. The
 809  * prefix always ends with a '/' character.
 810  */
 811 const char *setup_git_directory(void)
 812 {
 813         return setup_git_directory_gently(NULL);
 814 }
 815
 816 const char *resolve_gitdir(const char *suspect)
 817 {
 818         if (is_git_directory(suspect))
 819                 return suspect;
 820         return read_gitfile(suspect);
 821 }