setup.c

   1 #include "cache.h"
   2 #include "dir.h"
   3 #include "string-list.h"
   4
   5 static int inside_git_dir = -1;
   6 static int inside_work_tree = -1;
   7
   8 static char *prefix_path_gently(const char *prefix, int len, const char *path)
   9 {
  10         const char *orig = path;
  11         char *sanitized;
  12         if (is_absolute_path(orig)) {
  13                 const char *temp = real_path(path);
  14                 sanitized = xmalloc(len + strlen(temp) + 1);
  15                 strcpy(sanitized, temp);
  16         } else {
  17                 sanitized = xmalloc(len + strlen(path) + 1);
  18                 if (len)
  19                         memcpy(sanitized, prefix, len);
  20                 strcpy(sanitized + len, path);
  21         }
  22         if (normalize_path_copy(sanitized, sanitized))
  23                 goto error_out;
  24         if (is_absolute_path(orig)) {
  25                 size_t root_len, len, total;
  26                 const char *work_tree = get_git_work_tree();
  27                 if (!work_tree)
  28                         goto error_out;
  29                 len = strlen(work_tree);
  30                 root_len = offset_1st_component(work_tree);
  31                 total = strlen(sanitized) + 1;
  32                 if (strncmp(sanitized, work_tree, len) ||
  33                     (len > root_len && sanitized[len] != '\0' && sanitized[len] != '/')) {
  34                 error_out:
  35                         free(sanitized);
  36                         return NULL;
  37                 }
  38                 if (sanitized[len] == '/')
  39                         len++;
  40                 memmove(sanitized, sanitized + len, total - len);
  41         }
  42         return sanitized;
  43 }
  44
  45 char *prefix_path(const char *prefix, int len, const char *path)
  46 {
  47         char *r = prefix_path_gently(prefix, len, path);
  48         if (!r)
  49                 die("'%s' is outside repository", path);
  50         return r;
  51 }
  52
  53 int path_inside_repo(const char *prefix, const char *path)
  54 {
  55         int len = prefix ? strlen(prefix) : 0;
  56         char *r = prefix_path_gently(prefix, len, path);
  57         if (r) {
  58                 free(r);
  59                 return 1;
  60         }
  61         return 0;
  62 }
  63
  64 int check_filename(const char *prefix, const char *arg)
  65 {
  66         const char *name;
  67         struct stat st;
  68
  69         if (!prefixcmp(arg, ":/")) {
  70                 if (arg[2] == '\0') /* ":/" is root dir, always exists */
  71                         return 1;
  72                 name = arg + 2;
  73         } else if (prefix)
  74                 name = prefix_filename(prefix, strlen(prefix), arg);
  75         else
  76                 name = 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,
  85                                          const char *arg,
  86                                          int diagnose_misspelt_rev)
  87 {
  88         if (!diagnose_misspelt_rev)
  89                 die("%s: no such path in the working tree.\n"
  90                     "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
  91                     arg);
  92         /*
  93          * Saying "'(icase)foo' does not exist in the index" when the
  94          * user gave us ":(icase)foo" is just stupid.  A magic pathspec
  95          * begins with a colon and is followed by a non-alnum; do not
  96          * let maybe_die_on_misspelt_object_name() even trigger.
  97          */
  98         if (!(arg[0] == ':' && !isalnum(arg[1])))
  99                 maybe_die_on_misspelt_object_name(arg, prefix);
 100
 101         /* ... or fall back the most general message. */
 102         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 103             "Use '--' to separate paths from revisions, like this:\n"
 104             "'git <command> [<revision>...] -- [<file>...]'", arg);
 105
 106 }
 107
 108 /*
 109  * Verify a filename that we got as an argument for a pathspec
 110  * entry. Note that a filename that begins with "-" never verifies
 111  * as true, because even if such a filename were to exist, we want
 112  * it to be preceded by the "--" marker (or we want the user to
 113  * use a format like "./-filename")
 114  *
 115  * The "diagnose_misspelt_rev" is used to provide a user-friendly
 116  * diagnosis when dying upon finding that "name" is not a pathname.
 117  * If set to 1, the diagnosis will try to diagnose "name" as an
 118  * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 119  * will only complain about an inexisting file.
 120  *
 121  * This function is typically called to check that a "file or rev"
 122  * argument is unambiguous. In this case, the caller will want
 123  * diagnose_misspelt_rev == 1 when verifying the first non-rev
 124  * argument (which could have been a revision), and
 125  * diagnose_misspelt_rev == 0 for the next ones (because we already
 126  * saw a filename, there's not ambiguity anymore).
 127  */
 128 void verify_filename(const char *prefix,
 129                      const char *arg,
 130                      int diagnose_misspelt_rev)
 131 {
 132         if (*arg == '-')
 133                 die("bad flag '%s' used after filename", arg);
 134         if (check_filename(prefix, arg))
 135                 return;
 136         die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 137 }
 138
 139 /*
 140  * Opposite of the above: the command line did not have -- marker
 141  * and we parsed the arg as a refname.  It should not be interpretable
 142  * as a filename.
 143  */
 144 void verify_non_filename(const char *prefix, const char *arg)
 145 {
 146         if (!is_inside_work_tree() || is_inside_git_dir())
 147                 return;
 148         if (*arg == '-')
 149                 return; /* flag */
 150         if (!check_filename(prefix, arg))
 151                 return;
 152         die("ambiguous argument '%s': both revision and filename\n"
 153             "Use '--' to separate paths from revisions, like this:\n"
 154             "'git <command> [<revision>...] -- [<file>...]'", arg);
 155 }
 156
 157 /*
 158  * Magic pathspec
 159  *
 160  * NEEDSWORK: These need to be moved to dir.h or even to a new
 161  * pathspec.h when we restructure get_pathspec() users to use the
 162  * "struct pathspec" interface.
 163  *
 164  * Possible future magic semantics include stuff like:
 165  *
 166  *      { PATHSPEC_NOGLOB, '!', "noglob" },
 167  *      { PATHSPEC_ICASE, '\0', "icase" },
 168  *      { PATHSPEC_RECURSIVE, '*', "recursive" },
 169  *      { PATHSPEC_REGEXP, '\0', "regexp" },
 170  *
 171  */
 172 #define PATHSPEC_FROMTOP    (1<<0)
 173
 174 static struct pathspec_magic {
 175         unsigned bit;
 176         char mnemonic; /* this cannot be ':'! */
 177         const char *name;
 178 } pathspec_magic[] = {
 179         { PATHSPEC_FROMTOP, '/', "top" },
 180 };
 181
 182 /*
 183  * Take an element of a pathspec and check for magic signatures.
 184  * Append the result to the prefix.
 185  *
 186  * For now, we only parse the syntax and throw out anything other than
 187  * "top" magic.
 188  *
 189  * NEEDSWORK: This needs to be rewritten when we start migrating
 190  * get_pathspec() users to use the "struct pathspec" interface.  For
 191  * example, a pathspec element may be marked as case-insensitive, but
 192  * the prefix part must always match literally, and a single stupid
 193  * string cannot express such a case.
 194  */
 195 static const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
 196 {
 197         unsigned magic = 0;
 198         const char *copyfrom = elt;
 199         int i;
 200
 201         if (elt[0] != ':') {
 202                 ; /* nothing to do */
 203         } else if (elt[1] == '(') {
 204                 /* longhand */
 205                 const char *nextat;
 206                 for (copyfrom = elt + 2;
 207                      *copyfrom && *copyfrom != ')';
 208                      copyfrom = nextat) {
 209                         size_t len = strcspn(copyfrom, ",)");
 210                         if (copyfrom[len] == ',')
 211                                 nextat = copyfrom + len + 1;
 212                         else
 213                                 /* handle ')' and '\0' */
 214                                 nextat = copyfrom + len;
 215                         if (!len)
 216                                 continue;
 217                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 218                                 if (strlen(pathspec_magic[i].name) == len &&
 219                                     !strncmp(pathspec_magic[i].name, copyfrom, len)) {
 220                                         magic |= pathspec_magic[i].bit;
 221                                         break;
 222                                 }
 223                         if (ARRAY_SIZE(pathspec_magic) <= i)
 224                                 die("Invalid pathspec magic '%.*s' in '%s'",
 225                                     (int) len, copyfrom, elt);
 226                 }
 227                 if (*copyfrom != ')')
 228                         die("Missing ')' at the end of pathspec magic in '%s'", elt);
 229                 copyfrom++;
 230         } else {
 231                 /* shorthand */
 232                 for (copyfrom = elt + 1;
 233                      *copyfrom && *copyfrom != ':';
 234                      copyfrom++) {
 235                         char ch = *copyfrom;
 236
 237                         if (!is_pathspec_magic(ch))
 238                                 break;
 239                         for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
 240                                 if (pathspec_magic[i].mnemonic == ch) {
 241                                         magic |= pathspec_magic[i].bit;
 242                                         break;
 243                                 }
 244                         if (ARRAY_SIZE(pathspec_magic) <= i)
 245                                 die("Unimplemented pathspec magic '%c' in '%s'",
 246                                     ch, elt);
 247                 }
 248                 if (*copyfrom == ':')
 249                         copyfrom++;
 250         }
 251
 252         if (magic & PATHSPEC_FROMTOP)
 253                 return xstrdup(copyfrom);
 254         else
 255                 return prefix_path(prefix, prefixlen, copyfrom);
 256 }
 257
 258 /*
 259  * N.B. get_pathspec() is deprecated in favor of the "struct pathspec"
 260  * based interface - see pathspec_magic above.
 261  *
 262  * Arguments:
 263  *  - prefix - a path relative to the root of the working tree
 264  *  - pathspec - a list of paths underneath the prefix path
 265  *
 266  * Iterates over pathspec, prepending each path with prefix,
 267  * and return the resulting list.
 268  *
 269  * If pathspec is empty, return a singleton list containing prefix.
 270  *
 271  * If pathspec and prefix are both empty, return an empty list.
 272  *
 273  * This is typically used by built-in commands such as add.c, in order
 274  * to normalize argv arguments provided to the built-in into a list of
 275  * paths to process, all relative to the root of the working tree.
 276  */
 277 const char **get_pathspec(const char *prefix, const char **pathspec)
 278 {
 279         const char *entry = *pathspec;
 280         const char **src, **dst;
 281         int prefixlen;
 282
 283         if (!prefix && !entry)
 284                 return NULL;
 285
 286         if (!entry) {
 287                 static const char *spec[2];
 288                 spec[0] = prefix;
 289                 spec[1] = NULL;
 290                 return spec;
 291         }
 292
 293         /* Otherwise we have to re-write the entries.. */
 294         src = pathspec;
 295         dst = pathspec;
 296         prefixlen = prefix ? strlen(prefix) : 0;
 297         while (*src) {
 298                 *(dst++) = prefix_pathspec(prefix, prefixlen, *src);
 299                 src++;
 300         }
 301         *dst = NULL;
 302         if (!*pathspec)
 303                 return NULL;
 304         return pathspec;
 305 }
 306
 307 /*
 308  * Test if it looks like we're at a git directory.
 309  * We want to see:
 310  *
 311  *  - either an objects/ directory _or_ the proper
 312  *    GIT_OBJECT_DIRECTORY environment variable
 313  *  - a refs/ directory
 314  *  - either a HEAD symlink or a HEAD file that is formatted as
 315  *    a proper "ref:", or a regular file HEAD that has a properly
 316  *    formatted sha1 object name.
 317  */
 318 int is_git_directory(const char *suspect)
 319 {
 320         char path[PATH_MAX];
 321         size_t len = strlen(suspect);
 322
 323         if (PATH_MAX <= len + strlen("/objects"))
 324                 die("Too long path: %.*s", 60, suspect);
 325         strcpy(path, suspect);
 326         if (getenv(DB_ENVIRONMENT)) {
 327                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 328                         return 0;
 329         }
 330         else {
 331                 strcpy(path + len, "/objects");
 332                 if (access(path, X_OK))
 333                         return 0;
 334         }
 335
 336         strcpy(path + len, "/refs");
 337         if (access(path, X_OK))
 338                 return 0;
 339
 340         strcpy(path + len, "/HEAD");
 341         if (validate_headref(path))
 342                 return 0;
 343
 344         return 1;
 345 }
 346
 347 int is_inside_git_dir(void)
 348 {
 349         if (inside_git_dir < 0)
 350                 inside_git_dir = is_inside_dir(get_git_dir());
 351         return inside_git_dir;
 352 }
 353
 354 int is_inside_work_tree(void)
 355 {
 356         if (inside_work_tree < 0)
 357                 inside_work_tree = is_inside_dir(get_git_work_tree());
 358         return inside_work_tree;
 359 }
 360
 361 void setup_work_tree(void)
 362 {
 363         const char *work_tree, *git_dir;
 364         static int initialized = 0;
 365
 366         if (initialized)
 367                 return;
 368         work_tree = get_git_work_tree();
 369         git_dir = get_git_dir();
 370         if (!is_absolute_path(git_dir))
 371                 git_dir = real_path(get_git_dir());
 372         if (!work_tree || chdir(work_tree))
 373                 die("This operation must be run in a work tree");
 374
 375         /*
 376          * Make sure subsequent git processes find correct worktree
 377          * if $GIT_WORK_TREE is set relative
 378          */
 379         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 380                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 381
 382         set_git_dir(relative_path(git_dir, work_tree));
 383         initialized = 1;
 384 }
 385
 386 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 387 {
 388         char repo_config[PATH_MAX+1];
 389
 390         /*
 391          * git_config() can't be used here because it calls git_pathdup()
 392          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 393          * set git_dir to ".git".
 394          *
 395          * We are in gitdir setup, no git dir has been found useable yet.
 396          * Use a gentler version of git_config() to check if this repo
 397          * is a good one.
 398          */
 399         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 400         git_config_early(check_repository_format_version, NULL, repo_config);
 401         if (GIT_REPO_VERSION < repository_format_version) {
 402                 if (!nongit_ok)
 403                         die ("Expected git repo version <= %d, found %d",
 404                              GIT_REPO_VERSION, repository_format_version);
 405                 warning("Expected git repo version <= %d, found %d",
 406                         GIT_REPO_VERSION, repository_format_version);
 407                 warning("Please upgrade Git");
 408                 *nongit_ok = -1;
 409                 return -1;
 410         }
 411         return 0;
 412 }
 413
 414 /*
 415  * Try to read the location of the git directory from the .git file,
 416  * return path to git directory if found.
 417  */
 418 const char *read_gitfile(const char *path)
 419 {
 420         char *buf;
 421         char *dir;
 422         const char *slash;
 423         struct stat st;
 424         int fd;
 425         ssize_t len;
 426
 427         if (stat(path, &st))
 428                 return NULL;
 429         if (!S_ISREG(st.st_mode))
 430                 return NULL;
 431         fd = open(path, O_RDONLY);
 432         if (fd < 0)
 433                 die_errno("Error opening '%s'", path);
 434         buf = xmalloc(st.st_size + 1);
 435         len = read_in_full(fd, buf, st.st_size);
 436         close(fd);
 437         if (len != st.st_size)
 438                 die("Error reading %s", path);
 439         buf[len] = '\0';
 440         if (prefixcmp(buf, "gitdir: "))
 441                 die("Invalid gitfile format: %s", path);
 442         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 443                 len--;
 444         if (len < 9)
 445                 die("No path in gitfile: %s", path);
 446         buf[len] = '\0';
 447         dir = buf + 8;
 448
 449         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 450                 size_t pathlen = slash+1 - path;
 451                 size_t dirlen = pathlen + len - 8;
 452                 dir = xmalloc(dirlen + 1);
 453                 strncpy(dir, path, pathlen);
 454                 strncpy(dir + pathlen, buf + 8, len - 8);
 455                 dir[dirlen] = '\0';
 456                 free(buf);
 457                 buf = dir;
 458         }
 459
 460         if (!is_git_directory(dir))
 461                 die("Not a git repository: %s", dir);
 462         path = real_path(dir);
 463
 464         free(buf);
 465         return path;
 466 }
 467
 468 static const char *setup_explicit_git_dir(const char *gitdirenv,
 469                                           char *cwd, int len,
 470                                           int *nongit_ok)
 471 {
 472         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 473         const char *worktree;
 474         char *gitfile;
 475         int offset;
 476
 477         if (PATH_MAX - 40 < strlen(gitdirenv))
 478                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 479
 480         gitfile = (char*)read_gitfile(gitdirenv);
 481         if (gitfile) {
 482                 gitfile = xstrdup(gitfile);
 483                 gitdirenv = gitfile;
 484         }
 485
 486         if (!is_git_directory(gitdirenv)) {
 487                 if (nongit_ok) {
 488                         *nongit_ok = 1;
 489                         free(gitfile);
 490                         return NULL;
 491                 }
 492                 die("Not a git repository: '%s'", gitdirenv);
 493         }
 494
 495         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 496                 free(gitfile);
 497                 return NULL;
 498         }
 499
 500         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 501         if (work_tree_env)
 502                 set_git_work_tree(work_tree_env);
 503         else if (is_bare_repository_cfg > 0) {
 504                 if (git_work_tree_cfg) /* #22.2, #30 */
 505                         die("core.bare and core.worktree do not make sense");
 506
 507                 /* #18, #26 */
 508                 set_git_dir(gitdirenv);
 509                 free(gitfile);
 510                 return NULL;
 511         }
 512         else if (git_work_tree_cfg) { /* #6, #14 */
 513                 if (is_absolute_path(git_work_tree_cfg))
 514                         set_git_work_tree(git_work_tree_cfg);
 515                 else {
 516                         char core_worktree[PATH_MAX];
 517                         if (chdir(gitdirenv))
 518                                 die_errno("Could not chdir to '%s'", gitdirenv);
 519                         if (chdir(git_work_tree_cfg))
 520                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 521                         if (!getcwd(core_worktree, PATH_MAX))
 522                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 523                         if (chdir(cwd))
 524                                 die_errno("Could not come back to cwd");
 525                         set_git_work_tree(core_worktree);
 526                 }
 527         }
 528         else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 529                 /* #16d */
 530                 set_git_dir(gitdirenv);
 531                 free(gitfile);
 532                 return NULL;
 533         }
 534         else /* #2, #10 */
 535                 set_git_work_tree(".");
 536
 537         /* set_git_work_tree() must have been called by now */
 538         worktree = get_git_work_tree();
 539
 540         /* both get_git_work_tree() and cwd are already normalized */
 541         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 542                 set_git_dir(gitdirenv);
 543                 free(gitfile);
 544                 return NULL;
 545         }
 546
 547         offset = dir_inside_of(cwd, worktree);
 548         if (offset >= 0) {      /* cwd inside worktree? */
 549                 set_git_dir(real_path(gitdirenv));
 550                 if (chdir(worktree))
 551                         die_errno("Could not chdir to '%s'", worktree);
 552                 cwd[len++] = '/';
 553                 cwd[len] = '\0';
 554                 free(gitfile);
 555                 return cwd + offset;
 556         }
 557
 558         /* cwd outside worktree */
 559         set_git_dir(gitdirenv);
 560         free(gitfile);
 561         return NULL;
 562 }
 563
 564 static const char *setup_discovered_git_dir(const char *gitdir,
 565                                             char *cwd, int offset, int len,
 566                                             int *nongit_ok)
 567 {
 568         if (check_repository_format_gently(gitdir, nongit_ok))
 569                 return NULL;
 570
 571         /* --work-tree is set without --git-dir; use discovered one */
 572         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 573                 if (offset != len && !is_absolute_path(gitdir))
 574                         gitdir = xstrdup(real_path(gitdir));
 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         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 581         if (is_bare_repository_cfg > 0) {
 582                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 583                 if (chdir(cwd))
 584                         die_errno("Could not come back to cwd");
 585                 return NULL;
 586         }
 587
 588         /* #0, #1, #5, #8, #9, #12, #13 */
 589         set_git_work_tree(".");
 590         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 591                 set_git_dir(gitdir);
 592         inside_git_dir = 0;
 593         inside_work_tree = 1;
 594         if (offset == len)
 595                 return NULL;
 596
 597         /* Make "offset" point to past the '/', and add a '/' at the end */
 598         offset++;
 599         cwd[len++] = '/';
 600         cwd[len] = 0;
 601         return cwd + offset;
 602 }
 603
 604 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 605 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 606 {
 607         int root_len;
 608
 609         if (check_repository_format_gently(".", nongit_ok))
 610                 return NULL;
 611
 612         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 613
 614         /* --work-tree is set without --git-dir; use discovered one */
 615         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 616                 const char *gitdir;
 617
 618                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 619                 if (chdir(cwd))
 620                         die_errno("Could not come back to cwd");
 621                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 622         }
 623
 624         inside_git_dir = 1;
 625         inside_work_tree = 0;
 626         if (offset != len) {
 627                 if (chdir(cwd))
 628                         die_errno("Cannot come back to cwd");
 629                 root_len = offset_1st_component(cwd);
 630                 cwd[offset > root_len ? offset : root_len] = '\0';
 631                 set_git_dir(cwd);
 632         }
 633         else
 634                 set_git_dir(".");
 635         return NULL;
 636 }
 637
 638 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 639 {
 640         if (!nongit_ok)
 641                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 642         if (chdir(cwd))
 643                 die_errno("Cannot come back to cwd");
 644         *nongit_ok = 1;
 645         return NULL;
 646 }
 647
 648 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 649 {
 650         struct stat buf;
 651         if (stat(path, &buf)) {
 652                 die_errno("failed to stat '%*s%s%s'",
 653                                 prefix_len,
 654                                 prefix ? prefix : "",
 655                                 prefix ? "/" : "", path);
 656         }
 657         return buf.st_dev;
 658 }
 659
 660 /*
 661  * A "string_list_each_func_t" function that canonicalizes an entry
 662  * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 663  * discards it if unusable.  The presence of an empty entry in
 664  * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 665  * subsequent entries.
 666  */
 667 static int canonicalize_ceiling_entry(struct string_list_item *item,
 668                                       void *cb_data)
 669 {
 670         int *empty_entry_found = cb_data;
 671         char *ceil = item->string;
 672
 673         if (!*ceil) {
 674                 *empty_entry_found = 1;
 675                 return 0;
 676         } else if (!is_absolute_path(ceil)) {
 677                 return 0;
 678         } else if (*empty_entry_found) {
 679                 /* Keep entry but do not canonicalize it */
 680                 return 1;
 681         } else {
 682                 const char *real_path = real_path_if_valid(ceil);
 683                 if (!real_path)
 684                         return 0;
 685                 free(item->string);
 686                 item->string = xstrdup(real_path);
 687                 return 1;
 688         }
 689 }
 690
 691 /*
 692  * We cannot decide in this function whether we are in the work tree or
 693  * not, since the config can only be read _after_ this function was called.
 694  */
 695 static const char *setup_git_directory_gently_1(int *nongit_ok)
 696 {
 697         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 698         struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 699         static char cwd[PATH_MAX+1];
 700         const char *gitdirenv, *ret;
 701         char *gitfile;
 702         int len, offset, offset_parent, ceil_offset = -1;
 703         dev_t current_device = 0;
 704         int one_filesystem = 1;
 705
 706         /*
 707          * Let's assume that we are in a git repository.
 708          * If it turns out later that we are somewhere else, the value will be
 709          * updated accordingly.
 710          */
 711         if (nongit_ok)
 712                 *nongit_ok = 0;
 713
 714         if (!getcwd(cwd, sizeof(cwd)-1))
 715                 die_errno("Unable to read current working directory");
 716         offset = len = strlen(cwd);
 717
 718         /*
 719          * If GIT_DIR is set explicitly, we're not going
 720          * to do any discovery, but we still do repository
 721          * validation.
 722          */
 723         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 724         if (gitdirenv)
 725                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 726
 727         if (env_ceiling_dirs) {
 728                 int empty_entry_found = 0;
 729
 730                 string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 731                 filter_string_list(&ceiling_dirs, 0,
 732                                    canonicalize_ceiling_entry, &empty_entry_found);
 733                 ceil_offset = longest_ancestor_length(cwd, &ceiling_dirs);
 734                 string_list_clear(&ceiling_dirs, 0);
 735         }
 736
 737         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 738                 ceil_offset = 1;
 739
 740         /*
 741          * Test in the following order (relative to the cwd):
 742          * - .git (file containing "gitdir: <path>")
 743          * - .git/
 744          * - ./ (bare)
 745          * - ../.git
 746          * - ../.git/
 747          * - ../ (bare)
 748          * - ../../.git/
 749          *   etc.
 750          */
 751         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 752         if (one_filesystem)
 753                 current_device = get_device_or_die(".", NULL, 0);
 754         for (;;) {
 755                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 756                 if (gitfile)
 757                         gitdirenv = gitfile = xstrdup(gitfile);
 758                 else {
 759                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 760                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 761                 }
 762
 763                 if (gitdirenv) {
 764                         ret = setup_discovered_git_dir(gitdirenv,
 765                                                        cwd, offset, len,
 766                                                        nongit_ok);
 767                         free(gitfile);
 768                         return ret;
 769                 }
 770                 free(gitfile);
 771
 772                 if (is_git_directory("."))
 773                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 774
 775                 offset_parent = offset;
 776                 while (--offset_parent > ceil_offset && cwd[offset_parent] != '/');
 777                 if (offset_parent <= ceil_offset)
 778                         return setup_nongit(cwd, nongit_ok);
 779                 if (one_filesystem) {
 780                         dev_t parent_device = get_device_or_die("..", cwd, offset);
 781                         if (parent_device != current_device) {
 782                                 if (nongit_ok) {
 783                                         if (chdir(cwd))
 784                                                 die_errno("Cannot come back to cwd");
 785                                         *nongit_ok = 1;
 786                                         return NULL;
 787                                 }
 788                                 cwd[offset] = '\0';
 789                                 die("Not a git repository (or any parent up to mount point %s)\n"
 790                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 791                         }
 792                 }
 793                 if (chdir("..")) {
 794                         cwd[offset] = '\0';
 795                         die_errno("Cannot change to '%s/..'", cwd);
 796                 }
 797                 offset = offset_parent;
 798         }
 799 }
 800
 801 const char *setup_git_directory_gently(int *nongit_ok)
 802 {
 803         const char *prefix;
 804
 805         prefix = setup_git_directory_gently_1(nongit_ok);
 806         if (prefix)
 807                 setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 808         else
 809                 setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 810
 811         if (startup_info) {
 812                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 813                 startup_info->prefix = prefix;
 814         }
 815         return prefix;
 816 }
 817
 818 int git_config_perm(const char *var, const char *value)
 819 {
 820         int i;
 821         char *endptr;
 822
 823         if (value == NULL)
 824                 return PERM_GROUP;
 825
 826         if (!strcmp(value, "umask"))
 827                 return PERM_UMASK;
 828         if (!strcmp(value, "group"))
 829                 return PERM_GROUP;
 830         if (!strcmp(value, "all") ||
 831             !strcmp(value, "world") ||
 832             !strcmp(value, "everybody"))
 833                 return PERM_EVERYBODY;
 834
 835         /* Parse octal numbers */
 836         i = strtol(value, &endptr, 8);
 837
 838         /* If not an octal number, maybe true/false? */
 839         if (*endptr != 0)
 840                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 841
 842         /*
 843          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 844          * a chmod value to restrict to.
 845          */
 846         switch (i) {
 847         case PERM_UMASK:               /* 0 */
 848                 return PERM_UMASK;
 849         case OLD_PERM_GROUP:           /* 1 */
 850                 return PERM_GROUP;
 851         case OLD_PERM_EVERYBODY:       /* 2 */
 852                 return PERM_EVERYBODY;
 853         }
 854
 855         /* A filemode value was given: 0xxx */
 856
 857         if ((i & 0600) != 0600)
 858                 die("Problem with core.sharedRepository filemode value "
 859                     "(0%.3o).\nThe owner of files must always have "
 860                     "read and write permissions.", i);
 861
 862         /*
 863          * Mask filemode value. Others can not get write permission.
 864          * x flags for directories are handled separately.
 865          */
 866         return -(i & 0666);
 867 }
 868
 869 int check_repository_format_version(const char *var, const char *value, void *cb)
 870 {
 871         if (strcmp(var, "core.repositoryformatversion") == 0)
 872                 repository_format_version = git_config_int(var, value);
 873         else if (strcmp(var, "core.sharedrepository") == 0)
 874                 shared_repository = git_config_perm(var, value);
 875         else if (strcmp(var, "core.bare") == 0) {
 876                 is_bare_repository_cfg = git_config_bool(var, value);
 877                 if (is_bare_repository_cfg == 1)
 878                         inside_work_tree = -1;
 879         } else if (strcmp(var, "core.worktree") == 0) {
 880                 if (!value)
 881                         return config_error_nonbool(var);
 882                 free(git_work_tree_cfg);
 883                 git_work_tree_cfg = xstrdup(value);
 884                 inside_work_tree = -1;
 885         }
 886         return 0;
 887 }
 888
 889 int check_repository_format(void)
 890 {
 891         return check_repository_format_gently(get_git_dir(), NULL);
 892 }
 893
 894 /*
 895  * Returns the "prefix", a path to the current working directory
 896  * relative to the work tree root, or NULL, if the current working
 897  * directory is not a strict subdirectory of the work tree root. The
 898  * prefix always ends with a '/' character.
 899  */
 900 const char *setup_git_directory(void)
 901 {
 902         return setup_git_directory_gently(NULL);
 903 }
 904
 905 const char *resolve_gitdir(const char *suspect)
 906 {
 907         if (is_git_directory(suspect))
 908                 return suspect;
 909         return read_gitfile(suspect);
 910 }