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 static int work_tree_config_is_bogus;
   8 static struct string_list unknown_extensions = STRING_LIST_INIT_DUP;
   9
  10 /*
  11  * The input parameter must contain an absolute path, and it must already be
  12  * normalized.
  13  *
  14  * Find the part of an absolute path that lies inside the work tree by
  15  * dereferencing symlinks outside the work tree, for example:
  16  * /dir1/repo/dir2/file   (work tree is /dir1/repo)      -> dir2/file
  17  * /dir/file              (work tree is /)               -> dir/file
  18  * /dir/symlink1/symlink2 (symlink1 points to work tree) -> symlink2
  19  * /dir/repolink/file     (repolink points to /dir/repo) -> file
  20  * /dir/repo              (exactly equal to work tree)   -> (empty string)
  21  */
  22 static int abspath_part_inside_repo(char *path)
  23 {
  24         size_t len;
  25         size_t wtlen;
  26         char *path0;
  27         int off;
  28         const char *work_tree = get_git_work_tree();
  29
  30         if (!work_tree)
  31                 return -1;
  32         wtlen = strlen(work_tree);
  33         len = strlen(path);
  34         off = offset_1st_component(path);
  35
  36         /* check if work tree is already the prefix */
  37         if (wtlen <= len && !strncmp(path, work_tree, wtlen)) {
  38                 if (path[wtlen] == '/') {
  39                         memmove(path, path + wtlen + 1, len - wtlen);
  40                         return 0;
  41                 } else if (path[wtlen - 1] == '/' || path[wtlen] == '\0') {
  42                         /* work tree is the root, or the whole path */
  43                         memmove(path, path + wtlen, len - wtlen + 1);
  44                         return 0;
  45                 }
  46                 /* work tree might match beginning of a symlink to work tree */
  47                 off = wtlen;
  48         }
  49         path0 = path;
  50         path += off;
  51
  52         /* check each '/'-terminated level */
  53         while (*path) {
  54                 path++;
  55                 if (*path == '/') {
  56                         *path = '\0';
  57                         if (strcmp(real_path(path0), work_tree) == 0) {
  58                                 memmove(path0, path + 1, len - (path - path0));
  59                                 return 0;
  60                         }
  61                         *path = '/';
  62                 }
  63         }
  64
  65         /* check whole path */
  66         if (strcmp(real_path(path0), work_tree) == 0) {
  67                 *path0 = '\0';
  68                 return 0;
  69         }
  70
  71         return -1;
  72 }
  73
  74 /*
  75  * Normalize "path", prepending the "prefix" for relative paths. If
  76  * remaining_prefix is not NULL, return the actual prefix still
  77  * remains in the path. For example, prefix = sub1/sub2/ and path is
  78  *
  79  *  foo          -> sub1/sub2/foo  (full prefix)
  80  *  ../foo       -> sub1/foo       (remaining prefix is sub1/)
  81  *  ../../bar    -> bar            (no remaining prefix)
  82  *  ../../sub1/sub2/foo -> sub1/sub2/foo (but no remaining prefix)
  83  *  `pwd`/../bar -> sub1/bar       (no remaining prefix)
  84  */
  85 char *prefix_path_gently(const char *prefix, int len,
  86                          int *remaining_prefix, const char *path)
  87 {
  88         const char *orig = path;
  89         char *sanitized;
  90         if (is_absolute_path(orig)) {
  91                 sanitized = xmallocz(strlen(path));
  92                 if (remaining_prefix)
  93                         *remaining_prefix = 0;
  94                 if (normalize_path_copy_len(sanitized, path, remaining_prefix)) {
  95                         free(sanitized);
  96                         return NULL;
  97                 }
  98                 if (abspath_part_inside_repo(sanitized)) {
  99                         free(sanitized);
 100                         return NULL;
 101                 }
 102         } else {
 103                 sanitized = xstrfmt("%.*s%s", len, prefix, path);
 104                 if (remaining_prefix)
 105                         *remaining_prefix = len;
 106                 if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix)) {
 107                         free(sanitized);
 108                         return NULL;
 109                 }
 110         }
 111         return sanitized;
 112 }
 113
 114 char *prefix_path(const char *prefix, int len, const char *path)
 115 {
 116         char *r = prefix_path_gently(prefix, len, NULL, path);
 117         if (!r)
 118                 die("'%s' is outside repository", path);
 119         return r;
 120 }
 121
 122 int path_inside_repo(const char *prefix, const char *path)
 123 {
 124         int len = prefix ? strlen(prefix) : 0;
 125         char *r = prefix_path_gently(prefix, len, NULL, path);
 126         if (r) {
 127                 free(r);
 128                 return 1;
 129         }
 130         return 0;
 131 }
 132
 133 int check_filename(const char *prefix, const char *arg)
 134 {
 135         const char *name;
 136         struct stat st;
 137
 138         if (starts_with(arg, ":/")) {
 139                 if (arg[2] == '\0') /* ":/" is root dir, always exists */
 140                         return 1;
 141                 name = arg + 2;
 142         } else if (prefix)
 143                 name = prefix_filename(prefix, strlen(prefix), arg);
 144         else
 145                 name = arg;
 146         if (!lstat(name, &st))
 147                 return 1; /* file exists */
 148         if (errno == ENOENT || errno == ENOTDIR)
 149                 return 0; /* file does not exist */
 150         die_errno("failed to stat '%s'", arg);
 151 }
 152
 153 static void NORETURN die_verify_filename(const char *prefix,
 154                                          const char *arg,
 155                                          int diagnose_misspelt_rev)
 156 {
 157         if (!diagnose_misspelt_rev)
 158                 die("%s: no such path in the working tree.\n"
 159                     "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
 160                     arg);
 161         /*
 162          * Saying "'(icase)foo' does not exist in the index" when the
 163          * user gave us ":(icase)foo" is just stupid.  A magic pathspec
 164          * begins with a colon and is followed by a non-alnum; do not
 165          * let maybe_die_on_misspelt_object_name() even trigger.
 166          */
 167         if (!(arg[0] == ':' && !isalnum(arg[1])))
 168                 maybe_die_on_misspelt_object_name(arg, prefix);
 169
 170         /* ... or fall back the most general message. */
 171         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 172             "Use '--' to separate paths from revisions, like this:\n"
 173             "'git <command> [<revision>...] -- [<file>...]'", arg);
 174
 175 }
 176
 177 /*
 178  * Verify a filename that we got as an argument for a pathspec
 179  * entry. Note that a filename that begins with "-" never verifies
 180  * as true, because even if such a filename were to exist, we want
 181  * it to be preceded by the "--" marker (or we want the user to
 182  * use a format like "./-filename")
 183  *
 184  * The "diagnose_misspelt_rev" is used to provide a user-friendly
 185  * diagnosis when dying upon finding that "name" is not a pathname.
 186  * If set to 1, the diagnosis will try to diagnose "name" as an
 187  * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 188  * will only complain about an inexisting file.
 189  *
 190  * This function is typically called to check that a "file or rev"
 191  * argument is unambiguous. In this case, the caller will want
 192  * diagnose_misspelt_rev == 1 when verifying the first non-rev
 193  * argument (which could have been a revision), and
 194  * diagnose_misspelt_rev == 0 for the next ones (because we already
 195  * saw a filename, there's not ambiguity anymore).
 196  */
 197 void verify_filename(const char *prefix,
 198                      const char *arg,
 199                      int diagnose_misspelt_rev)
 200 {
 201         if (*arg == '-')
 202                 die("bad flag '%s' used after filename", arg);
 203         if (check_filename(prefix, arg) || !no_wildcard(arg))
 204                 return;
 205         die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 206 }
 207
 208 /*
 209  * Opposite of the above: the command line did not have -- marker
 210  * and we parsed the arg as a refname.  It should not be interpretable
 211  * as a filename.
 212  */
 213 void verify_non_filename(const char *prefix, const char *arg)
 214 {
 215         if (!is_inside_work_tree() || is_inside_git_dir())
 216                 return;
 217         if (*arg == '-')
 218                 return; /* flag */
 219         if (!check_filename(prefix, arg))
 220                 return;
 221         die("ambiguous argument '%s': both revision and filename\n"
 222             "Use '--' to separate paths from revisions, like this:\n"
 223             "'git <command> [<revision>...] -- [<file>...]'", arg);
 224 }
 225
 226 int get_common_dir(struct strbuf *sb, const char *gitdir)
 227 {
 228         const char *git_env_common_dir = getenv(GIT_COMMON_DIR_ENVIRONMENT);
 229         if (git_env_common_dir) {
 230                 strbuf_addstr(sb, git_env_common_dir);
 231                 return 1;
 232         } else {
 233                 return get_common_dir_noenv(sb, gitdir);
 234         }
 235 }
 236
 237 int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
 238 {
 239         struct strbuf data = STRBUF_INIT;
 240         struct strbuf path = STRBUF_INIT;
 241         int ret = 0;
 242
 243         strbuf_addf(&path, "%s/commondir", gitdir);
 244         if (file_exists(path.buf)) {
 245                 if (strbuf_read_file(&data, path.buf, 0) <= 0)
 246                         die_errno(_("failed to read %s"), path.buf);
 247                 while (data.len && (data.buf[data.len - 1] == '\n' ||
 248                                     data.buf[data.len - 1] == '\r'))
 249                         data.len--;
 250                 data.buf[data.len] = '\0';
 251                 strbuf_reset(&path);
 252                 if (!is_absolute_path(data.buf))
 253                         strbuf_addf(&path, "%s/", gitdir);
 254                 strbuf_addbuf(&path, &data);
 255                 strbuf_addstr(sb, real_path(path.buf));
 256                 ret = 1;
 257         } else
 258                 strbuf_addstr(sb, gitdir);
 259         strbuf_release(&data);
 260         strbuf_release(&path);
 261         return ret;
 262 }
 263
 264 /*
 265  * Test if it looks like we're at a git directory.
 266  * We want to see:
 267  *
 268  *  - either an objects/ directory _or_ the proper
 269  *    GIT_OBJECT_DIRECTORY environment variable
 270  *  - a refs/ directory
 271  *  - either a HEAD symlink or a HEAD file that is formatted as
 272  *    a proper "ref:", or a regular file HEAD that has a properly
 273  *    formatted sha1 object name.
 274  */
 275 int is_git_directory(const char *suspect)
 276 {
 277         struct strbuf path = STRBUF_INIT;
 278         int ret = 0;
 279         size_t len;
 280
 281         /* Check worktree-related signatures */
 282         strbuf_addf(&path, "%s/HEAD", suspect);
 283         if (validate_headref(path.buf))
 284                 goto done;
 285
 286         strbuf_reset(&path);
 287         get_common_dir(&path, suspect);
 288         len = path.len;
 289
 290         /* Check non-worktree-related signatures */
 291         if (getenv(DB_ENVIRONMENT)) {
 292                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 293                         goto done;
 294         }
 295         else {
 296                 strbuf_setlen(&path, len);
 297                 strbuf_addstr(&path, "/objects");
 298                 if (access(path.buf, X_OK))
 299                         goto done;
 300         }
 301
 302         strbuf_setlen(&path, len);
 303         strbuf_addstr(&path, "/refs");
 304         if (access(path.buf, X_OK))
 305                 goto done;
 306
 307         ret = 1;
 308 done:
 309         strbuf_release(&path);
 310         return ret;
 311 }
 312
 313 int is_nonbare_repository_dir(struct strbuf *path)
 314 {
 315         int ret = 0;
 316         int gitfile_error;
 317         size_t orig_path_len = path->len;
 318         assert(orig_path_len != 0);
 319         strbuf_complete(path, '/');
 320         strbuf_addstr(path, ".git");
 321         if (read_gitfile_gently(path->buf, &gitfile_error) || is_git_directory(path->buf))
 322                 ret = 1;
 323         if (gitfile_error == READ_GITFILE_ERR_OPEN_FAILED ||
 324             gitfile_error == READ_GITFILE_ERR_READ_FAILED)
 325                 ret = 1;
 326         strbuf_setlen(path, orig_path_len);
 327         return ret;
 328 }
 329
 330 int is_inside_git_dir(void)
 331 {
 332         if (inside_git_dir < 0)
 333                 inside_git_dir = is_inside_dir(get_git_dir());
 334         return inside_git_dir;
 335 }
 336
 337 int is_inside_work_tree(void)
 338 {
 339         if (inside_work_tree < 0)
 340                 inside_work_tree = is_inside_dir(get_git_work_tree());
 341         return inside_work_tree;
 342 }
 343
 344 void setup_work_tree(void)
 345 {
 346         const char *work_tree, *git_dir;
 347         static int initialized = 0;
 348
 349         if (initialized)
 350                 return;
 351
 352         if (work_tree_config_is_bogus)
 353                 die("unable to set up work tree using invalid config");
 354
 355         work_tree = get_git_work_tree();
 356         git_dir = get_git_dir();
 357         if (!is_absolute_path(git_dir))
 358                 git_dir = real_path(get_git_dir());
 359         if (!work_tree || chdir(work_tree))
 360                 die("This operation must be run in a work tree");
 361
 362         /*
 363          * Make sure subsequent git processes find correct worktree
 364          * if $GIT_WORK_TREE is set relative
 365          */
 366         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 367                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 368
 369         set_git_dir(remove_leading_path(git_dir, work_tree));
 370         initialized = 1;
 371 }
 372
 373 static int check_repo_format(const char *var, const char *value, void *cb)
 374 {
 375         const char *ext;
 376
 377         if (strcmp(var, "core.repositoryformatversion") == 0)
 378                 repository_format_version = git_config_int(var, value);
 379         else if (skip_prefix(var, "extensions.", &ext)) {
 380                 /*
 381                  * record any known extensions here; otherwise,
 382                  * we fall through to recording it as unknown, and
 383                  * check_repository_format will complain
 384                  */
 385                 if (!strcmp(ext, "noop"))
 386                         ;
 387                 else if (!strcmp(ext, "preciousobjects"))
 388                         repository_format_precious_objects = git_config_bool(var, value);
 389                 else
 390                         string_list_append(&unknown_extensions, ext);
 391         }
 392         return 0;
 393 }
 394
 395 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 396 {
 397         struct strbuf sb = STRBUF_INIT;
 398         const char *repo_config;
 399         config_fn_t fn;
 400         int ret = 0;
 401
 402         string_list_clear(&unknown_extensions, 0);
 403
 404         if (get_common_dir(&sb, gitdir))
 405                 fn = check_repo_format;
 406         else
 407                 fn = check_repository_format_version;
 408         strbuf_addstr(&sb, "/config");
 409         repo_config = sb.buf;
 410
 411         /*
 412          * Ignore return value; for historical reasons, we must treat a missing
 413          * config file as a noop (git-init relies on this).
 414          */
 415         git_config_from_file(fn, repo_config, NULL);
 416         if (GIT_REPO_VERSION_READ < repository_format_version) {
 417                 if (!nongit_ok)
 418                         die ("Expected git repo version <= %d, found %d",
 419                              GIT_REPO_VERSION_READ, repository_format_version);
 420                 warning("Expected git repo version <= %d, found %d",
 421                         GIT_REPO_VERSION_READ, repository_format_version);
 422                 warning("Please upgrade Git");
 423                 *nongit_ok = -1;
 424                 ret = -1;
 425         }
 426
 427         if (repository_format_version >= 1 && unknown_extensions.nr) {
 428                 int i;
 429
 430                 if (!nongit_ok)
 431                         die("unknown repository extension: %s",
 432                             unknown_extensions.items[0].string);
 433
 434                 for (i = 0; i < unknown_extensions.nr; i++)
 435                         warning("unknown repository extension: %s",
 436                                 unknown_extensions.items[i].string);
 437                 *nongit_ok = -1;
 438                 ret = -1;
 439         }
 440
 441         strbuf_release(&sb);
 442         return ret;
 443 }
 444
 445 /*
 446  * Try to read the location of the git directory from the .git file,
 447  * return path to git directory if found.
 448  *
 449  * On failure, if return_error_code is not NULL, return_error_code
 450  * will be set to an error code and NULL will be returned. If
 451  * return_error_code is NULL the function will die instead (for most
 452  * cases).
 453  */
 454 const char *read_gitfile_gently(const char *path, int *return_error_code)
 455 {
 456         const int max_file_size = 1 << 20;  /* 1MB */
 457         int error_code = 0;
 458         char *buf = NULL;
 459         char *dir = NULL;
 460         const char *slash;
 461         struct stat st;
 462         int fd;
 463         ssize_t len;
 464
 465         if (stat(path, &st)) {
 466                 error_code = READ_GITFILE_ERR_STAT_FAILED;
 467                 goto cleanup_return;
 468         }
 469         if (!S_ISREG(st.st_mode)) {
 470                 error_code = READ_GITFILE_ERR_NOT_A_FILE;
 471                 goto cleanup_return;
 472         }
 473         if (st.st_size > max_file_size) {
 474                 error_code = READ_GITFILE_ERR_TOO_LARGE;
 475                 goto cleanup_return;
 476         }
 477         fd = open(path, O_RDONLY);
 478         if (fd < 0) {
 479                 error_code = READ_GITFILE_ERR_OPEN_FAILED;
 480                 goto cleanup_return;
 481         }
 482         buf = xmallocz(st.st_size);
 483         len = read_in_full(fd, buf, st.st_size);
 484         close(fd);
 485         if (len != st.st_size) {
 486                 error_code = READ_GITFILE_ERR_READ_FAILED;
 487                 goto cleanup_return;
 488         }
 489         if (!starts_with(buf, "gitdir: ")) {
 490                 error_code = READ_GITFILE_ERR_INVALID_FORMAT;
 491                 goto cleanup_return;
 492         }
 493         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 494                 len--;
 495         if (len < 9) {
 496                 error_code = READ_GITFILE_ERR_NO_PATH;
 497                 goto cleanup_return;
 498         }
 499         buf[len] = '\0';
 500         dir = buf + 8;
 501
 502         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 503                 size_t pathlen = slash+1 - path;
 504                 dir = xstrfmt("%.*s%.*s", (int)pathlen, path,
 505                               (int)(len - 8), buf + 8);
 506                 free(buf);
 507                 buf = dir;
 508         }
 509         if (!is_git_directory(dir)) {
 510                 error_code = READ_GITFILE_ERR_NOT_A_REPO;
 511                 goto cleanup_return;
 512         }
 513         path = real_path(dir);
 514
 515 cleanup_return:
 516         if (return_error_code)
 517                 *return_error_code = error_code;
 518         else if (error_code) {
 519                 switch (error_code) {
 520                 case READ_GITFILE_ERR_STAT_FAILED:
 521                 case READ_GITFILE_ERR_NOT_A_FILE:
 522                         /* non-fatal; follow return path */
 523                         break;
 524                 case READ_GITFILE_ERR_OPEN_FAILED:
 525                         die_errno("Error opening '%s'", path);
 526                 case READ_GITFILE_ERR_TOO_LARGE:
 527                         die("Too large to be a .git file: '%s'", path);
 528                 case READ_GITFILE_ERR_READ_FAILED:
 529                         die("Error reading %s", path);
 530                 case READ_GITFILE_ERR_INVALID_FORMAT:
 531                         die("Invalid gitfile format: %s", path);
 532                 case READ_GITFILE_ERR_NO_PATH:
 533                         die("No path in gitfile: %s", path);
 534                 case READ_GITFILE_ERR_NOT_A_REPO:
 535                         die("Not a git repository: %s", dir);
 536                 default:
 537                         assert(0);
 538                 }
 539         }
 540
 541         free(buf);
 542         return error_code ? NULL : path;
 543 }
 544
 545 static const char *setup_explicit_git_dir(const char *gitdirenv,
 546                                           struct strbuf *cwd,
 547                                           int *nongit_ok)
 548 {
 549         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 550         const char *worktree;
 551         char *gitfile;
 552         int offset;
 553
 554         if (PATH_MAX - 40 < strlen(gitdirenv))
 555                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 556
 557         gitfile = (char*)read_gitfile(gitdirenv);
 558         if (gitfile) {
 559                 gitfile = xstrdup(gitfile);
 560                 gitdirenv = gitfile;
 561         }
 562
 563         if (!is_git_directory(gitdirenv)) {
 564                 if (nongit_ok) {
 565                         *nongit_ok = 1;
 566                         free(gitfile);
 567                         return NULL;
 568                 }
 569                 die("Not a git repository: '%s'", gitdirenv);
 570         }
 571
 572         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 573                 free(gitfile);
 574                 return NULL;
 575         }
 576
 577         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 578         if (work_tree_env)
 579                 set_git_work_tree(work_tree_env);
 580         else if (is_bare_repository_cfg > 0) {
 581                 if (git_work_tree_cfg) {
 582                         /* #22.2, #30 */
 583                         warning("core.bare and core.worktree do not make sense");
 584                         work_tree_config_is_bogus = 1;
 585                 }
 586
 587                 /* #18, #26 */
 588                 set_git_dir(gitdirenv);
 589                 free(gitfile);
 590                 return NULL;
 591         }
 592         else if (git_work_tree_cfg) { /* #6, #14 */
 593                 if (is_absolute_path(git_work_tree_cfg))
 594                         set_git_work_tree(git_work_tree_cfg);
 595                 else {
 596                         char *core_worktree;
 597                         if (chdir(gitdirenv))
 598                                 die_errno("Could not chdir to '%s'", gitdirenv);
 599                         if (chdir(git_work_tree_cfg))
 600                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 601                         core_worktree = xgetcwd();
 602                         if (chdir(cwd->buf))
 603                                 die_errno("Could not come back to cwd");
 604                         set_git_work_tree(core_worktree);
 605                         free(core_worktree);
 606                 }
 607         }
 608         else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 609                 /* #16d */
 610                 set_git_dir(gitdirenv);
 611                 free(gitfile);
 612                 return NULL;
 613         }
 614         else /* #2, #10 */
 615                 set_git_work_tree(".");
 616
 617         /* set_git_work_tree() must have been called by now */
 618         worktree = get_git_work_tree();
 619
 620         /* both get_git_work_tree() and cwd are already normalized */
 621         if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */
 622                 set_git_dir(gitdirenv);
 623                 free(gitfile);
 624                 return NULL;
 625         }
 626
 627         offset = dir_inside_of(cwd->buf, worktree);
 628         if (offset >= 0) {      /* cwd inside worktree? */
 629                 set_git_dir(real_path(gitdirenv));
 630                 if (chdir(worktree))
 631                         die_errno("Could not chdir to '%s'", worktree);
 632                 strbuf_addch(cwd, '/');
 633                 free(gitfile);
 634                 return cwd->buf + offset;
 635         }
 636
 637         /* cwd outside worktree */
 638         set_git_dir(gitdirenv);
 639         free(gitfile);
 640         return NULL;
 641 }
 642
 643 static const char *setup_discovered_git_dir(const char *gitdir,
 644                                             struct strbuf *cwd, int offset,
 645                                             int *nongit_ok)
 646 {
 647         if (check_repository_format_gently(gitdir, nongit_ok))
 648                 return NULL;
 649
 650         /* --work-tree is set without --git-dir; use discovered one */
 651         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 652                 if (offset != cwd->len && !is_absolute_path(gitdir))
 653                         gitdir = xstrdup(real_path(gitdir));
 654                 if (chdir(cwd->buf))
 655                         die_errno("Could not come back to cwd");
 656                 return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 657         }
 658
 659         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 660         if (is_bare_repository_cfg > 0) {
 661                 set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));
 662                 if (chdir(cwd->buf))
 663                         die_errno("Could not come back to cwd");
 664                 return NULL;
 665         }
 666
 667         /* #0, #1, #5, #8, #9, #12, #13 */
 668         set_git_work_tree(".");
 669         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 670                 set_git_dir(gitdir);
 671         inside_git_dir = 0;
 672         inside_work_tree = 1;
 673         if (offset == cwd->len)
 674                 return NULL;
 675
 676         /* Make "offset" point to past the '/', and add a '/' at the end */
 677         offset++;
 678         strbuf_addch(cwd, '/');
 679         return cwd->buf + offset;
 680 }
 681
 682 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 683 static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
 684                                       int *nongit_ok)
 685 {
 686         int root_len;
 687
 688         if (check_repository_format_gently(".", nongit_ok))
 689                 return NULL;
 690
 691         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 692
 693         /* --work-tree is set without --git-dir; use discovered one */
 694         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 695                 const char *gitdir;
 696
 697                 gitdir = offset == cwd->len ? "." : xmemdupz(cwd->buf, offset);
 698                 if (chdir(cwd->buf))
 699                         die_errno("Could not come back to cwd");
 700                 return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 701         }
 702
 703         inside_git_dir = 1;
 704         inside_work_tree = 0;
 705         if (offset != cwd->len) {
 706                 if (chdir(cwd->buf))
 707                         die_errno("Cannot come back to cwd");
 708                 root_len = offset_1st_component(cwd->buf);
 709                 strbuf_setlen(cwd, offset > root_len ? offset : root_len);
 710                 set_git_dir(cwd->buf);
 711         }
 712         else
 713                 set_git_dir(".");
 714         return NULL;
 715 }
 716
 717 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 718 {
 719         if (!nongit_ok)
 720                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 721         if (chdir(cwd))
 722                 die_errno("Cannot come back to cwd");
 723         *nongit_ok = 1;
 724         return NULL;
 725 }
 726
 727 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 728 {
 729         struct stat buf;
 730         if (stat(path, &buf)) {
 731                 die_errno("failed to stat '%*s%s%s'",
 732                                 prefix_len,
 733                                 prefix ? prefix : "",
 734                                 prefix ? "/" : "", path);
 735         }
 736         return buf.st_dev;
 737 }
 738
 739 /*
 740  * A "string_list_each_func_t" function that canonicalizes an entry
 741  * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 742  * discards it if unusable.  The presence of an empty entry in
 743  * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 744  * subsequent entries.
 745  */
 746 static int canonicalize_ceiling_entry(struct string_list_item *item,
 747                                       void *cb_data)
 748 {
 749         int *empty_entry_found = cb_data;
 750         char *ceil = item->string;
 751
 752         if (!*ceil) {
 753                 *empty_entry_found = 1;
 754                 return 0;
 755         } else if (!is_absolute_path(ceil)) {
 756                 return 0;
 757         } else if (*empty_entry_found) {
 758                 /* Keep entry but do not canonicalize it */
 759                 return 1;
 760         } else {
 761                 const char *real_path = real_path_if_valid(ceil);
 762                 if (!real_path)
 763                         return 0;
 764                 free(item->string);
 765                 item->string = xstrdup(real_path);
 766                 return 1;
 767         }
 768 }
 769
 770 /*
 771  * We cannot decide in this function whether we are in the work tree or
 772  * not, since the config can only be read _after_ this function was called.
 773  */
 774 static const char *setup_git_directory_gently_1(int *nongit_ok)
 775 {
 776         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 777         struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 778         static struct strbuf cwd = STRBUF_INIT;
 779         const char *gitdirenv, *ret;
 780         char *gitfile;
 781         int offset, offset_parent, ceil_offset = -1;
 782         dev_t current_device = 0;
 783         int one_filesystem = 1;
 784
 785         /*
 786          * We may have read an incomplete configuration before
 787          * setting-up the git directory. If so, clear the cache so
 788          * that the next queries to the configuration reload complete
 789          * configuration (including the per-repo config file that we
 790          * ignored previously).
 791          */
 792         git_config_clear();
 793
 794         /*
 795          * Let's assume that we are in a git repository.
 796          * If it turns out later that we are somewhere else, the value will be
 797          * updated accordingly.
 798          */
 799         if (nongit_ok)
 800                 *nongit_ok = 0;
 801
 802         if (strbuf_getcwd(&cwd))
 803                 die_errno("Unable to read current working directory");
 804         offset = cwd.len;
 805
 806         /*
 807          * If GIT_DIR is set explicitly, we're not going
 808          * to do any discovery, but we still do repository
 809          * validation.
 810          */
 811         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 812         if (gitdirenv)
 813                 return setup_explicit_git_dir(gitdirenv, &cwd, nongit_ok);
 814
 815         if (env_ceiling_dirs) {
 816                 int empty_entry_found = 0;
 817
 818                 string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 819                 filter_string_list(&ceiling_dirs, 0,
 820                                    canonicalize_ceiling_entry, &empty_entry_found);
 821                 ceil_offset = longest_ancestor_length(cwd.buf, &ceiling_dirs);
 822                 string_list_clear(&ceiling_dirs, 0);
 823         }
 824
 825         if (ceil_offset < 0 && has_dos_drive_prefix(cwd.buf))
 826                 ceil_offset = 1;
 827
 828         /*
 829          * Test in the following order (relative to the cwd):
 830          * - .git (file containing "gitdir: <path>")
 831          * - .git/
 832          * - ./ (bare)
 833          * - ../.git
 834          * - ../.git/
 835          * - ../ (bare)
 836          * - ../../.git/
 837          *   etc.
 838          */
 839         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 840         if (one_filesystem)
 841                 current_device = get_device_or_die(".", NULL, 0);
 842         for (;;) {
 843                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 844                 if (gitfile)
 845                         gitdirenv = gitfile = xstrdup(gitfile);
 846                 else {
 847                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 848                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 849                 }
 850
 851                 if (gitdirenv) {
 852                         ret = setup_discovered_git_dir(gitdirenv,
 853                                                        &cwd, offset,
 854                                                        nongit_ok);
 855                         free(gitfile);
 856                         return ret;
 857                 }
 858                 free(gitfile);
 859
 860                 if (is_git_directory("."))
 861                         return setup_bare_git_dir(&cwd, offset, nongit_ok);
 862
 863                 offset_parent = offset;
 864                 while (--offset_parent > ceil_offset && cwd.buf[offset_parent] != '/');
 865                 if (offset_parent <= ceil_offset)
 866                         return setup_nongit(cwd.buf, nongit_ok);
 867                 if (one_filesystem) {
 868                         dev_t parent_device = get_device_or_die("..", cwd.buf,
 869                                                                 offset);
 870                         if (parent_device != current_device) {
 871                                 if (nongit_ok) {
 872                                         if (chdir(cwd.buf))
 873                                                 die_errno("Cannot come back to cwd");
 874                                         *nongit_ok = 1;
 875                                         return NULL;
 876                                 }
 877                                 strbuf_setlen(&cwd, offset);
 878                                 die("Not a git repository (or any parent up to mount point %s)\n"
 879                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).",
 880                                     cwd.buf);
 881                         }
 882                 }
 883                 if (chdir("..")) {
 884                         strbuf_setlen(&cwd, offset);
 885                         die_errno("Cannot change to '%s/..'", cwd.buf);
 886                 }
 887                 offset = offset_parent;
 888         }
 889 }
 890
 891 const char *setup_git_directory_gently(int *nongit_ok)
 892 {
 893         const char *prefix;
 894
 895         prefix = setup_git_directory_gently_1(nongit_ok);
 896         if (prefix)
 897                 setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 898         else
 899                 setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 900
 901         if (startup_info) {
 902                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 903                 startup_info->prefix = prefix;
 904         }
 905         return prefix;
 906 }
 907
 908 int git_config_perm(const char *var, const char *value)
 909 {
 910         int i;
 911         char *endptr;
 912
 913         if (value == NULL)
 914                 return PERM_GROUP;
 915
 916         if (!strcmp(value, "umask"))
 917                 return PERM_UMASK;
 918         if (!strcmp(value, "group"))
 919                 return PERM_GROUP;
 920         if (!strcmp(value, "all") ||
 921             !strcmp(value, "world") ||
 922             !strcmp(value, "everybody"))
 923                 return PERM_EVERYBODY;
 924
 925         /* Parse octal numbers */
 926         i = strtol(value, &endptr, 8);
 927
 928         /* If not an octal number, maybe true/false? */
 929         if (*endptr != 0)
 930                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 931
 932         /*
 933          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 934          * a chmod value to restrict to.
 935          */
 936         switch (i) {
 937         case PERM_UMASK:               /* 0 */
 938                 return PERM_UMASK;
 939         case OLD_PERM_GROUP:           /* 1 */
 940                 return PERM_GROUP;
 941         case OLD_PERM_EVERYBODY:       /* 2 */
 942                 return PERM_EVERYBODY;
 943         }
 944
 945         /* A filemode value was given: 0xxx */
 946
 947         if ((i & 0600) != 0600)
 948                 die("Problem with core.sharedRepository filemode value "
 949                     "(0%.3o).\nThe owner of files must always have "
 950                     "read and write permissions.", i);
 951
 952         /*
 953          * Mask filemode value. Others can not get write permission.
 954          * x flags for directories are handled separately.
 955          */
 956         return -(i & 0666);
 957 }
 958
 959 int check_repository_format_version(const char *var, const char *value, void *cb)
 960 {
 961         int ret = check_repo_format(var, value, cb);
 962         if (ret)
 963                 return ret;
 964         if (strcmp(var, "core.bare") == 0) {
 965                 is_bare_repository_cfg = git_config_bool(var, value);
 966                 if (is_bare_repository_cfg == 1)
 967                         inside_work_tree = -1;
 968         } else if (strcmp(var, "core.worktree") == 0) {
 969                 if (!value)
 970                         return config_error_nonbool(var);
 971                 free(git_work_tree_cfg);
 972                 git_work_tree_cfg = xstrdup(value);
 973                 inside_work_tree = -1;
 974         }
 975         return 0;
 976 }
 977
 978 void check_repository_format(void)
 979 {
 980         check_repository_format_gently(get_git_dir(), NULL);
 981 }
 982
 983 /*
 984  * Returns the "prefix", a path to the current working directory
 985  * relative to the work tree root, or NULL, if the current working
 986  * directory is not a strict subdirectory of the work tree root. The
 987  * prefix always ends with a '/' character.
 988  */
 989 const char *setup_git_directory(void)
 990 {
 991         return setup_git_directory_gently(NULL);
 992 }
 993
 994 const char *resolve_gitdir(const char *suspect)
 995 {
 996         if (is_git_directory(suspect))
 997                 return suspect;
 998         return read_gitfile(suspect);
 999 }
1000
1001 /* if any standard file descriptor is missing open it to /dev/null */
1002 void sanitize_stdfds(void)
1003 {
1004         int fd = open("/dev/null", O_RDWR, 0);
1005         while (fd != -1 && fd < 2)
1006                 fd = dup(fd);
1007         if (fd == -1)
1008                 die_errno("open /dev/null or dup failed");
1009         if (fd > 2)
1010                 close(fd);
1011 }
1012
1013 int daemonize(void)
1014 {
1015 #ifdef NO_POSIX_GOODIES
1016         errno = ENOSYS;
1017         return -1;
1018 #else
1019         switch (fork()) {
1020                 case 0:
1021                         break;
1022                 case -1:
1023                         die_errno("fork failed");
1024                 default:
1025                         exit(0);
1026         }
1027         if (setsid() == -1)
1028                 die_errno("setsid failed");
1029         close(0);
1030         close(1);
1031         close(2);
1032         sanitize_stdfds();
1033         return 0;
1034 #endif
1035 }