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         struct strbuf sb = STRBUF_INIT;
 364         const char *work_tree, *git_dir;
 365         static int initialized = 0;
 366
 367         if (initialized)
 368                 return;
 369         work_tree = get_git_work_tree();
 370         git_dir = get_git_dir();
 371         if (!is_absolute_path(git_dir))
 372                 git_dir = real_path(get_git_dir());
 373         if (!work_tree || chdir(work_tree))
 374                 die("This operation must be run in a work tree");
 375
 376         /*
 377          * Make sure subsequent git processes find correct worktree
 378          * if $GIT_WORK_TREE is set relative
 379          */
 380         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 381                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 382
 383         set_git_dir(relative_path(git_dir, work_tree, &sb));
 384         initialized = 1;
 385
 386         strbuf_release(&sb);
 387 }
 388
 389 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 390 {
 391         char repo_config[PATH_MAX+1];
 392
 393         /*
 394          * git_config() can't be used here because it calls git_pathdup()
 395          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 396          * set git_dir to ".git".
 397          *
 398          * We are in gitdir setup, no git dir has been found useable yet.
 399          * Use a gentler version of git_config() to check if this repo
 400          * is a good one.
 401          */
 402         snprintf(repo_config, PATH_MAX, "%s/config", gitdir);
 403         git_config_early(check_repository_format_version, NULL, repo_config);
 404         if (GIT_REPO_VERSION < repository_format_version) {
 405                 if (!nongit_ok)
 406                         die ("Expected git repo version <= %d, found %d",
 407                              GIT_REPO_VERSION, repository_format_version);
 408                 warning("Expected git repo version <= %d, found %d",
 409                         GIT_REPO_VERSION, repository_format_version);
 410                 warning("Please upgrade Git");
 411                 *nongit_ok = -1;
 412                 return -1;
 413         }
 414         return 0;
 415 }
 416
 417 /*
 418  * Try to read the location of the git directory from the .git file,
 419  * return path to git directory if found.
 420  */
 421 const char *read_gitfile(const char *path)
 422 {
 423         char *buf;
 424         char *dir;
 425         const char *slash;
 426         struct stat st;
 427         int fd;
 428         ssize_t len;
 429
 430         if (stat(path, &st))
 431                 return NULL;
 432         if (!S_ISREG(st.st_mode))
 433                 return NULL;
 434         fd = open(path, O_RDONLY);
 435         if (fd < 0)
 436                 die_errno("Error opening '%s'", path);
 437         buf = xmalloc(st.st_size + 1);
 438         len = read_in_full(fd, buf, st.st_size);
 439         close(fd);
 440         if (len != st.st_size)
 441                 die("Error reading %s", path);
 442         buf[len] = '\0';
 443         if (prefixcmp(buf, "gitdir: "))
 444                 die("Invalid gitfile format: %s", path);
 445         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 446                 len--;
 447         if (len < 9)
 448                 die("No path in gitfile: %s", path);
 449         buf[len] = '\0';
 450         dir = buf + 8;
 451
 452         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 453                 size_t pathlen = slash+1 - path;
 454                 size_t dirlen = pathlen + len - 8;
 455                 dir = xmalloc(dirlen + 1);
 456                 strncpy(dir, path, pathlen);
 457                 strncpy(dir + pathlen, buf + 8, len - 8);
 458                 dir[dirlen] = '\0';
 459                 free(buf);
 460                 buf = dir;
 461         }
 462
 463         if (!is_git_directory(dir))
 464                 die("Not a git repository: %s", dir);
 465         path = real_path(dir);
 466
 467         free(buf);
 468         return path;
 469 }
 470
 471 static const char *setup_explicit_git_dir(const char *gitdirenv,
 472                                           char *cwd, int len,
 473                                           int *nongit_ok)
 474 {
 475         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 476         const char *worktree;
 477         char *gitfile;
 478         int offset;
 479
 480         if (PATH_MAX - 40 < strlen(gitdirenv))
 481                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 482
 483         gitfile = (char*)read_gitfile(gitdirenv);
 484         if (gitfile) {
 485                 gitfile = xstrdup(gitfile);
 486                 gitdirenv = gitfile;
 487         }
 488
 489         if (!is_git_directory(gitdirenv)) {
 490                 if (nongit_ok) {
 491                         *nongit_ok = 1;
 492                         free(gitfile);
 493                         return NULL;
 494                 }
 495                 die("Not a git repository: '%s'", gitdirenv);
 496         }
 497
 498         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 499                 free(gitfile);
 500                 return NULL;
 501         }
 502
 503         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 504         if (work_tree_env)
 505                 set_git_work_tree(work_tree_env);
 506         else if (is_bare_repository_cfg > 0) {
 507                 if (git_work_tree_cfg) /* #22.2, #30 */
 508                         die("core.bare and core.worktree do not make sense");
 509
 510                 /* #18, #26 */
 511                 set_git_dir(gitdirenv);
 512                 free(gitfile);
 513                 return NULL;
 514         }
 515         else if (git_work_tree_cfg) { /* #6, #14 */
 516                 if (is_absolute_path(git_work_tree_cfg))
 517                         set_git_work_tree(git_work_tree_cfg);
 518                 else {
 519                         char core_worktree[PATH_MAX];
 520                         if (chdir(gitdirenv))
 521                                 die_errno("Could not chdir to '%s'", gitdirenv);
 522                         if (chdir(git_work_tree_cfg))
 523                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 524                         if (!getcwd(core_worktree, PATH_MAX))
 525                                 die_errno("Could not get directory '%s'", git_work_tree_cfg);
 526                         if (chdir(cwd))
 527                                 die_errno("Could not come back to cwd");
 528                         set_git_work_tree(core_worktree);
 529                 }
 530         }
 531         else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 532                 /* #16d */
 533                 set_git_dir(gitdirenv);
 534                 free(gitfile);
 535                 return NULL;
 536         }
 537         else /* #2, #10 */
 538                 set_git_work_tree(".");
 539
 540         /* set_git_work_tree() must have been called by now */
 541         worktree = get_git_work_tree();
 542
 543         /* both get_git_work_tree() and cwd are already normalized */
 544         if (!strcmp(cwd, worktree)) { /* cwd == worktree */
 545                 set_git_dir(gitdirenv);
 546                 free(gitfile);
 547                 return NULL;
 548         }
 549
 550         offset = dir_inside_of(cwd, worktree);
 551         if (offset >= 0) {      /* cwd inside worktree? */
 552                 set_git_dir(real_path(gitdirenv));
 553                 if (chdir(worktree))
 554                         die_errno("Could not chdir to '%s'", worktree);
 555                 cwd[len++] = '/';
 556                 cwd[len] = '\0';
 557                 free(gitfile);
 558                 return cwd + offset;
 559         }
 560
 561         /* cwd outside worktree */
 562         set_git_dir(gitdirenv);
 563         free(gitfile);
 564         return NULL;
 565 }
 566
 567 static const char *setup_discovered_git_dir(const char *gitdir,
 568                                             char *cwd, int offset, int len,
 569                                             int *nongit_ok)
 570 {
 571         if (check_repository_format_gently(gitdir, nongit_ok))
 572                 return NULL;
 573
 574         /* --work-tree is set without --git-dir; use discovered one */
 575         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 576                 if (offset != len && !is_absolute_path(gitdir))
 577                         gitdir = xstrdup(real_path(gitdir));
 578                 if (chdir(cwd))
 579                         die_errno("Could not come back to cwd");
 580                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 581         }
 582
 583         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 584         if (is_bare_repository_cfg > 0) {
 585                 set_git_dir(offset == len ? gitdir : real_path(gitdir));
 586                 if (chdir(cwd))
 587                         die_errno("Could not come back to cwd");
 588                 return NULL;
 589         }
 590
 591         /* #0, #1, #5, #8, #9, #12, #13 */
 592         set_git_work_tree(".");
 593         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 594                 set_git_dir(gitdir);
 595         inside_git_dir = 0;
 596         inside_work_tree = 1;
 597         if (offset == len)
 598                 return NULL;
 599
 600         /* Make "offset" point to past the '/', and add a '/' at the end */
 601         offset++;
 602         cwd[len++] = '/';
 603         cwd[len] = 0;
 604         return cwd + offset;
 605 }
 606
 607 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 608 static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
 609 {
 610         int root_len;
 611
 612         if (check_repository_format_gently(".", nongit_ok))
 613                 return NULL;
 614
 615         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 616
 617         /* --work-tree is set without --git-dir; use discovered one */
 618         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 619                 const char *gitdir;
 620
 621                 gitdir = offset == len ? "." : xmemdupz(cwd, offset);
 622                 if (chdir(cwd))
 623                         die_errno("Could not come back to cwd");
 624                 return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
 625         }
 626
 627         inside_git_dir = 1;
 628         inside_work_tree = 0;
 629         if (offset != len) {
 630                 if (chdir(cwd))
 631                         die_errno("Cannot come back to cwd");
 632                 root_len = offset_1st_component(cwd);
 633                 cwd[offset > root_len ? offset : root_len] = '\0';
 634                 set_git_dir(cwd);
 635         }
 636         else
 637                 set_git_dir(".");
 638         return NULL;
 639 }
 640
 641 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 642 {
 643         if (!nongit_ok)
 644                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 645         if (chdir(cwd))
 646                 die_errno("Cannot come back to cwd");
 647         *nongit_ok = 1;
 648         return NULL;
 649 }
 650
 651 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 652 {
 653         struct stat buf;
 654         if (stat(path, &buf)) {
 655                 die_errno("failed to stat '%*s%s%s'",
 656                                 prefix_len,
 657                                 prefix ? prefix : "",
 658                                 prefix ? "/" : "", path);
 659         }
 660         return buf.st_dev;
 661 }
 662
 663 /*
 664  * A "string_list_each_func_t" function that canonicalizes an entry
 665  * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 666  * discards it if unusable.  The presence of an empty entry in
 667  * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 668  * subsequent entries.
 669  */
 670 static int canonicalize_ceiling_entry(struct string_list_item *item,
 671                                       void *cb_data)
 672 {
 673         int *empty_entry_found = cb_data;
 674         char *ceil = item->string;
 675
 676         if (!*ceil) {
 677                 *empty_entry_found = 1;
 678                 return 0;
 679         } else if (!is_absolute_path(ceil)) {
 680                 return 0;
 681         } else if (*empty_entry_found) {
 682                 /* Keep entry but do not canonicalize it */
 683                 return 1;
 684         } else {
 685                 const char *real_path = real_path_if_valid(ceil);
 686                 if (!real_path)
 687                         return 0;
 688                 free(item->string);
 689                 item->string = xstrdup(real_path);
 690                 return 1;
 691         }
 692 }
 693
 694 /*
 695  * We cannot decide in this function whether we are in the work tree or
 696  * not, since the config can only be read _after_ this function was called.
 697  */
 698 static const char *setup_git_directory_gently_1(int *nongit_ok)
 699 {
 700         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 701         struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 702         static char cwd[PATH_MAX+1];
 703         const char *gitdirenv, *ret;
 704         char *gitfile;
 705         int len, offset, offset_parent, ceil_offset = -1;
 706         dev_t current_device = 0;
 707         int one_filesystem = 1;
 708
 709         /*
 710          * Let's assume that we are in a git repository.
 711          * If it turns out later that we are somewhere else, the value will be
 712          * updated accordingly.
 713          */
 714         if (nongit_ok)
 715                 *nongit_ok = 0;
 716
 717         if (!getcwd(cwd, sizeof(cwd)-1))
 718                 die_errno("Unable to read current working directory");
 719         offset = len = strlen(cwd);
 720
 721         /*
 722          * If GIT_DIR is set explicitly, we're not going
 723          * to do any discovery, but we still do repository
 724          * validation.
 725          */
 726         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 727         if (gitdirenv)
 728                 return setup_explicit_git_dir(gitdirenv, cwd, len, nongit_ok);
 729
 730         if (env_ceiling_dirs) {
 731                 int empty_entry_found = 0;
 732
 733                 string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 734                 filter_string_list(&ceiling_dirs, 0,
 735                                    canonicalize_ceiling_entry, &empty_entry_found);
 736                 ceil_offset = longest_ancestor_length(cwd, &ceiling_dirs);
 737                 string_list_clear(&ceiling_dirs, 0);
 738         }
 739
 740         if (ceil_offset < 0 && has_dos_drive_prefix(cwd))
 741                 ceil_offset = 1;
 742
 743         /*
 744          * Test in the following order (relative to the cwd):
 745          * - .git (file containing "gitdir: <path>")
 746          * - .git/
 747          * - ./ (bare)
 748          * - ../.git
 749          * - ../.git/
 750          * - ../ (bare)
 751          * - ../../.git/
 752          *   etc.
 753          */
 754         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 755         if (one_filesystem)
 756                 current_device = get_device_or_die(".", NULL, 0);
 757         for (;;) {
 758                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 759                 if (gitfile)
 760                         gitdirenv = gitfile = xstrdup(gitfile);
 761                 else {
 762                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 763                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 764                 }
 765
 766                 if (gitdirenv) {
 767                         ret = setup_discovered_git_dir(gitdirenv,
 768                                                        cwd, offset, len,
 769                                                        nongit_ok);
 770                         free(gitfile);
 771                         return ret;
 772                 }
 773                 free(gitfile);
 774
 775                 if (is_git_directory("."))
 776                         return setup_bare_git_dir(cwd, offset, len, nongit_ok);
 777
 778                 offset_parent = offset;
 779                 while (--offset_parent > ceil_offset && cwd[offset_parent] != '/');
 780                 if (offset_parent <= ceil_offset)
 781                         return setup_nongit(cwd, nongit_ok);
 782                 if (one_filesystem) {
 783                         dev_t parent_device = get_device_or_die("..", cwd, offset);
 784                         if (parent_device != current_device) {
 785                                 if (nongit_ok) {
 786                                         if (chdir(cwd))
 787                                                 die_errno("Cannot come back to cwd");
 788                                         *nongit_ok = 1;
 789                                         return NULL;
 790                                 }
 791                                 cwd[offset] = '\0';
 792                                 die("Not a git repository (or any parent up to mount point %s)\n"
 793                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).", cwd);
 794                         }
 795                 }
 796                 if (chdir("..")) {
 797                         cwd[offset] = '\0';
 798                         die_errno("Cannot change to '%s/..'", cwd);
 799                 }
 800                 offset = offset_parent;
 801         }
 802 }
 803
 804 const char *setup_git_directory_gently(int *nongit_ok)
 805 {
 806         const char *prefix;
 807
 808         prefix = setup_git_directory_gently_1(nongit_ok);
 809         if (prefix)
 810                 setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 811         else
 812                 setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 813
 814         if (startup_info) {
 815                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 816                 startup_info->prefix = prefix;
 817         }
 818         return prefix;
 819 }
 820
 821 int git_config_perm(const char *var, const char *value)
 822 {
 823         int i;
 824         char *endptr;
 825
 826         if (value == NULL)
 827                 return PERM_GROUP;
 828
 829         if (!strcmp(value, "umask"))
 830                 return PERM_UMASK;
 831         if (!strcmp(value, "group"))
 832                 return PERM_GROUP;
 833         if (!strcmp(value, "all") ||
 834             !strcmp(value, "world") ||
 835             !strcmp(value, "everybody"))
 836                 return PERM_EVERYBODY;
 837
 838         /* Parse octal numbers */
 839         i = strtol(value, &endptr, 8);
 840
 841         /* If not an octal number, maybe true/false? */
 842         if (*endptr != 0)
 843                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 844
 845         /*
 846          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 847          * a chmod value to restrict to.
 848          */
 849         switch (i) {
 850         case PERM_UMASK:               /* 0 */
 851                 return PERM_UMASK;
 852         case OLD_PERM_GROUP:           /* 1 */
 853                 return PERM_GROUP;
 854         case OLD_PERM_EVERYBODY:       /* 2 */
 855                 return PERM_EVERYBODY;
 856         }
 857
 858         /* A filemode value was given: 0xxx */
 859
 860         if ((i & 0600) != 0600)
 861                 die("Problem with core.sharedRepository filemode value "
 862                     "(0%.3o).\nThe owner of files must always have "
 863                     "read and write permissions.", i);
 864
 865         /*
 866          * Mask filemode value. Others can not get write permission.
 867          * x flags for directories are handled separately.
 868          */
 869         return -(i & 0666);
 870 }
 871
 872 int check_repository_format_version(const char *var, const char *value, void *cb)
 873 {
 874         if (strcmp(var, "core.repositoryformatversion") == 0)
 875                 repository_format_version = git_config_int(var, value);
 876         else if (strcmp(var, "core.sharedrepository") == 0)
 877                 shared_repository = git_config_perm(var, value);
 878         else if (strcmp(var, "core.bare") == 0) {
 879                 is_bare_repository_cfg = git_config_bool(var, value);
 880                 if (is_bare_repository_cfg == 1)
 881                         inside_work_tree = -1;
 882         } else if (strcmp(var, "core.worktree") == 0) {
 883                 if (!value)
 884                         return config_error_nonbool(var);
 885                 free(git_work_tree_cfg);
 886                 git_work_tree_cfg = xstrdup(value);
 887                 inside_work_tree = -1;
 888         }
 889         return 0;
 890 }
 891
 892 int check_repository_format(void)
 893 {
 894         return check_repository_format_gently(get_git_dir(), NULL);
 895 }
 896
 897 /*
 898  * Returns the "prefix", a path to the current working directory
 899  * relative to the work tree root, or NULL, if the current working
 900  * directory is not a strict subdirectory of the work tree root. The
 901  * prefix always ends with a '/' character.
 902  */
 903 const char *setup_git_directory(void)
 904 {
 905         return setup_git_directory_gently(NULL);
 906 }
 907
 908 const char *resolve_gitdir(const char *suspect)
 909 {
 910         if (is_git_directory(suspect))
 911                 return suspect;
 912         return read_gitfile(suspect);
 913 }
 914
 915 /* if any standard file descriptor is missing open it to /dev/null */
 916 void sanitize_stdfds(void)
 917 {
 918         int fd = open("/dev/null", O_RDWR, 0);
 919         while (fd != -1 && fd < 2)
 920                 fd = dup(fd);
 921         if (fd == -1)
 922                 die_errno("open /dev/null or dup failed");
 923         if (fd > 2)
 924                 close(fd);
 925 }