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 = xmalloc(strlen(path) + 1);
  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 (!no_wildcard(arg))
 143                 return 1;
 144         else if (prefix)
 145                 name = prefix_filename(prefix, strlen(prefix), arg);
 146         else
 147                 name = arg;
 148         if (!lstat(name, &st))
 149                 return 1; /* file exists */
 150         if (errno == ENOENT || errno == ENOTDIR)
 151                 return 0; /* file does not exist */
 152         die_errno("failed to stat '%s'", arg);
 153 }
 154
 155 static void NORETURN die_verify_filename(const char *prefix,
 156                                          const char *arg,
 157                                          int diagnose_misspelt_rev)
 158 {
 159         if (!diagnose_misspelt_rev)
 160                 die("%s: no such path in the working tree.\n"
 161                     "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
 162                     arg);
 163         /*
 164          * Saying "'(icase)foo' does not exist in the index" when the
 165          * user gave us ":(icase)foo" is just stupid.  A magic pathspec
 166          * begins with a colon and is followed by a non-alnum; do not
 167          * let maybe_die_on_misspelt_object_name() even trigger.
 168          */
 169         if (!(arg[0] == ':' && !isalnum(arg[1])))
 170                 maybe_die_on_misspelt_object_name(arg, prefix);
 171
 172         /* ... or fall back the most general message. */
 173         die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 174             "Use '--' to separate paths from revisions, like this:\n"
 175             "'git <command> [<revision>...] -- [<file>...]'", arg);
 176
 177 }
 178
 179 /*
 180  * Verify a filename that we got as an argument for a pathspec
 181  * entry. Note that a filename that begins with "-" never verifies
 182  * as true, because even if such a filename were to exist, we want
 183  * it to be preceded by the "--" marker (or we want the user to
 184  * use a format like "./-filename")
 185  *
 186  * The "diagnose_misspelt_rev" is used to provide a user-friendly
 187  * diagnosis when dying upon finding that "name" is not a pathname.
 188  * If set to 1, the diagnosis will try to diagnose "name" as an
 189  * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 190  * will only complain about an inexisting file.
 191  *
 192  * This function is typically called to check that a "file or rev"
 193  * argument is unambiguous. In this case, the caller will want
 194  * diagnose_misspelt_rev == 1 when verifying the first non-rev
 195  * argument (which could have been a revision), and
 196  * diagnose_misspelt_rev == 0 for the next ones (because we already
 197  * saw a filename, there's not ambiguity anymore).
 198  */
 199 void verify_filename(const char *prefix,
 200                      const char *arg,
 201                      int diagnose_misspelt_rev)
 202 {
 203         if (*arg == '-')
 204                 die("bad flag '%s' used after filename", arg);
 205         if (check_filename(prefix, arg))
 206                 return;
 207         die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 208 }
 209
 210 /*
 211  * Opposite of the above: the command line did not have -- marker
 212  * and we parsed the arg as a refname.  It should not be interpretable
 213  * as a filename.
 214  */
 215 void verify_non_filename(const char *prefix, const char *arg)
 216 {
 217         if (!is_inside_work_tree() || is_inside_git_dir())
 218                 return;
 219         if (*arg == '-')
 220                 return; /* flag */
 221         if (!check_filename(prefix, arg))
 222                 return;
 223         die("ambiguous argument '%s': both revision and filename\n"
 224             "Use '--' to separate paths from revisions, like this:\n"
 225             "'git <command> [<revision>...] -- [<file>...]'", arg);
 226 }
 227
 228 int get_common_dir(struct strbuf *sb, const char *gitdir)
 229 {
 230         const char *git_env_common_dir = getenv(GIT_COMMON_DIR_ENVIRONMENT);
 231         if (git_env_common_dir) {
 232                 strbuf_addstr(sb, git_env_common_dir);
 233                 return 1;
 234         } else {
 235                 return get_common_dir_noenv(sb, gitdir);
 236         }
 237 }
 238
 239 int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
 240 {
 241         struct strbuf data = STRBUF_INIT;
 242         struct strbuf path = STRBUF_INIT;
 243         int ret = 0;
 244
 245         strbuf_addf(&path, "%s/commondir", gitdir);
 246         if (file_exists(path.buf)) {
 247                 if (strbuf_read_file(&data, path.buf, 0) <= 0)
 248                         die_errno(_("failed to read %s"), path.buf);
 249                 while (data.len && (data.buf[data.len - 1] == '\n' ||
 250                                     data.buf[data.len - 1] == '\r'))
 251                         data.len--;
 252                 data.buf[data.len] = '\0';
 253                 strbuf_reset(&path);
 254                 if (!is_absolute_path(data.buf))
 255                         strbuf_addf(&path, "%s/", gitdir);
 256                 strbuf_addbuf(&path, &data);
 257                 strbuf_addstr(sb, real_path(path.buf));
 258                 ret = 1;
 259         } else
 260                 strbuf_addstr(sb, gitdir);
 261         strbuf_release(&data);
 262         strbuf_release(&path);
 263         return ret;
 264 }
 265
 266 /*
 267  * Test if it looks like we're at a git directory.
 268  * We want to see:
 269  *
 270  *  - either an objects/ directory _or_ the proper
 271  *    GIT_OBJECT_DIRECTORY environment variable
 272  *  - a refs/ directory
 273  *  - either a HEAD symlink or a HEAD file that is formatted as
 274  *    a proper "ref:", or a regular file HEAD that has a properly
 275  *    formatted sha1 object name.
 276  */
 277 int is_git_directory(const char *suspect)
 278 {
 279         struct strbuf path = STRBUF_INIT;
 280         int ret = 0;
 281         size_t len;
 282
 283         /* Check worktree-related signatures */
 284         strbuf_addf(&path, "%s/HEAD", suspect);
 285         if (validate_headref(path.buf))
 286                 goto done;
 287
 288         strbuf_reset(&path);
 289         get_common_dir(&path, suspect);
 290         len = path.len;
 291
 292         /* Check non-worktree-related signatures */
 293         if (getenv(DB_ENVIRONMENT)) {
 294                 if (access(getenv(DB_ENVIRONMENT), X_OK))
 295                         goto done;
 296         }
 297         else {
 298                 strbuf_setlen(&path, len);
 299                 strbuf_addstr(&path, "/objects");
 300                 if (access(path.buf, X_OK))
 301                         goto done;
 302         }
 303
 304         strbuf_setlen(&path, len);
 305         strbuf_addstr(&path, "/refs");
 306         if (access(path.buf, X_OK))
 307                 goto done;
 308
 309         ret = 1;
 310 done:
 311         strbuf_release(&path);
 312         return ret;
 313 }
 314
 315 int is_nonbare_repository_dir(struct strbuf *path)
 316 {
 317         int ret = 0;
 318         int gitfile_error;
 319         size_t orig_path_len = path->len;
 320         assert(orig_path_len != 0);
 321         strbuf_complete(path, '/');
 322         strbuf_addstr(path, ".git");
 323         if (read_gitfile_gently(path->buf, &gitfile_error) || is_git_directory(path->buf))
 324                 ret = 1;
 325         if (gitfile_error == READ_GITFILE_ERR_OPEN_FAILED ||
 326             gitfile_error == READ_GITFILE_ERR_READ_FAILED)
 327                 ret = 1;
 328         strbuf_setlen(path, orig_path_len);
 329         return ret;
 330 }
 331
 332 int is_inside_git_dir(void)
 333 {
 334         if (inside_git_dir < 0)
 335                 inside_git_dir = is_inside_dir(get_git_dir());
 336         return inside_git_dir;
 337 }
 338
 339 int is_inside_work_tree(void)
 340 {
 341         if (inside_work_tree < 0)
 342                 inside_work_tree = is_inside_dir(get_git_work_tree());
 343         return inside_work_tree;
 344 }
 345
 346 void setup_work_tree(void)
 347 {
 348         const char *work_tree, *git_dir;
 349         static int initialized = 0;
 350
 351         if (initialized)
 352                 return;
 353
 354         if (work_tree_config_is_bogus)
 355                 die("unable to set up work tree using invalid config");
 356
 357         work_tree = get_git_work_tree();
 358         git_dir = get_git_dir();
 359         if (!is_absolute_path(git_dir))
 360                 git_dir = real_path(get_git_dir());
 361         if (!work_tree || chdir(work_tree))
 362                 die("This operation must be run in a work tree");
 363
 364         /*
 365          * Make sure subsequent git processes find correct worktree
 366          * if $GIT_WORK_TREE is set relative
 367          */
 368         if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 369                 setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 370
 371         set_git_dir(remove_leading_path(git_dir, work_tree));
 372         initialized = 1;
 373 }
 374
 375 static int check_repo_format(const char *var, const char *value, void *cb)
 376 {
 377         const char *ext;
 378
 379         if (strcmp(var, "core.repositoryformatversion") == 0)
 380                 repository_format_version = git_config_int(var, value);
 381         else if (strcmp(var, "core.sharedrepository") == 0)
 382                 shared_repository = git_config_perm(var, value);
 383         else if (skip_prefix(var, "extensions.", &ext)) {
 384                 /*
 385                  * record any known extensions here; otherwise,
 386                  * we fall through to recording it as unknown, and
 387                  * check_repository_format will complain
 388                  */
 389                 if (!strcmp(ext, "noop"))
 390                         ;
 391                 else if (!strcmp(ext, "preciousobjects"))
 392                         repository_format_precious_objects = git_config_bool(var, value);
 393                 else
 394                         string_list_append(&unknown_extensions, ext);
 395         }
 396         return 0;
 397 }
 398
 399 static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 400 {
 401         struct strbuf sb = STRBUF_INIT;
 402         const char *repo_config;
 403         config_fn_t fn;
 404         int ret = 0;
 405
 406         string_list_clear(&unknown_extensions, 0);
 407
 408         if (get_common_dir(&sb, gitdir))
 409                 fn = check_repo_format;
 410         else
 411                 fn = check_repository_format_version;
 412         strbuf_addstr(&sb, "/config");
 413         repo_config = sb.buf;
 414
 415         /*
 416          * git_config() can't be used here because it calls git_pathdup()
 417          * to get $GIT_CONFIG/config. That call will make setup_git_env()
 418          * set git_dir to ".git".
 419          *
 420          * We are in gitdir setup, no git dir has been found useable yet.
 421          * Use a gentler version of git_config() to check if this repo
 422          * is a good one.
 423          */
 424         git_config_early(fn, NULL, repo_config);
 425         if (GIT_REPO_VERSION_READ < repository_format_version) {
 426                 if (!nongit_ok)
 427                         die ("Expected git repo version <= %d, found %d",
 428                              GIT_REPO_VERSION_READ, repository_format_version);
 429                 warning("Expected git repo version <= %d, found %d",
 430                         GIT_REPO_VERSION_READ, repository_format_version);
 431                 warning("Please upgrade Git");
 432                 *nongit_ok = -1;
 433                 ret = -1;
 434         }
 435
 436         if (repository_format_version >= 1 && unknown_extensions.nr) {
 437                 int i;
 438
 439                 if (!nongit_ok)
 440                         die("unknown repository extension: %s",
 441                             unknown_extensions.items[0].string);
 442
 443                 for (i = 0; i < unknown_extensions.nr; i++)
 444                         warning("unknown repository extension: %s",
 445                                 unknown_extensions.items[i].string);
 446                 *nongit_ok = -1;
 447                 ret = -1;
 448         }
 449
 450         strbuf_release(&sb);
 451         return ret;
 452 }
 453
 454 static void update_linked_gitdir(const char *gitfile, const char *gitdir)
 455 {
 456         struct strbuf path = STRBUF_INIT;
 457         struct stat st;
 458
 459         strbuf_addf(&path, "%s/gitdir", gitdir);
 460         if (stat(path.buf, &st) || st.st_mtime + 24 * 3600 < time(NULL))
 461                 write_file(path.buf, "%s", gitfile);
 462         strbuf_release(&path);
 463 }
 464
 465 /*
 466  * Try to read the location of the git directory from the .git file,
 467  * return path to git directory if found.
 468  *
 469  * On failure, if return_error_code is not NULL, return_error_code
 470  * will be set to an error code and NULL will be returned. If
 471  * return_error_code is NULL the function will die instead (for most
 472  * cases).
 473  */
 474 const char *read_gitfile_gently(const char *path, int *return_error_code)
 475 {
 476         const int max_file_size = 1 << 20;  /* 1MB */
 477         int error_code = 0;
 478         char *buf = NULL;
 479         char *dir = NULL;
 480         const char *slash;
 481         struct stat st;
 482         int fd;
 483         ssize_t len;
 484
 485         if (stat(path, &st)) {
 486                 error_code = READ_GITFILE_ERR_STAT_FAILED;
 487                 goto cleanup_return;
 488         }
 489         if (!S_ISREG(st.st_mode)) {
 490                 error_code = READ_GITFILE_ERR_NOT_A_FILE;
 491                 goto cleanup_return;
 492         }
 493         if (st.st_size > max_file_size) {
 494                 error_code = READ_GITFILE_ERR_TOO_LARGE;
 495                 goto cleanup_return;
 496         }
 497         fd = open(path, O_RDONLY);
 498         if (fd < 0) {
 499                 error_code = READ_GITFILE_ERR_OPEN_FAILED;
 500                 goto cleanup_return;
 501         }
 502         buf = xmalloc(st.st_size + 1);
 503         len = read_in_full(fd, buf, st.st_size);
 504         close(fd);
 505         if (len != st.st_size) {
 506                 error_code = READ_GITFILE_ERR_READ_FAILED;
 507                 goto cleanup_return;
 508         }
 509         buf[len] = '\0';
 510         if (!starts_with(buf, "gitdir: ")) {
 511                 error_code = READ_GITFILE_ERR_INVALID_FORMAT;
 512                 goto cleanup_return;
 513         }
 514         while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 515                 len--;
 516         if (len < 9) {
 517                 error_code = READ_GITFILE_ERR_NO_PATH;
 518                 goto cleanup_return;
 519         }
 520         buf[len] = '\0';
 521         dir = buf + 8;
 522
 523         if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 524                 size_t pathlen = slash+1 - path;
 525                 dir = xstrfmt("%.*s%.*s", (int)pathlen, path,
 526                               (int)(len - 8), buf + 8);
 527                 free(buf);
 528                 buf = dir;
 529         }
 530         if (!is_git_directory(dir)) {
 531                 error_code = READ_GITFILE_ERR_NOT_A_REPO;
 532                 goto cleanup_return;
 533         }
 534         update_linked_gitdir(path, dir);
 535         path = real_path(dir);
 536
 537 cleanup_return:
 538         if (return_error_code)
 539                 *return_error_code = error_code;
 540         else if (error_code) {
 541                 switch (error_code) {
 542                 case READ_GITFILE_ERR_STAT_FAILED:
 543                 case READ_GITFILE_ERR_NOT_A_FILE:
 544                         /* non-fatal; follow return path */
 545                         break;
 546                 case READ_GITFILE_ERR_OPEN_FAILED:
 547                         die_errno("Error opening '%s'", path);
 548                 case READ_GITFILE_ERR_TOO_LARGE:
 549                         die("Too large to be a .git file: '%s'", path);
 550                 case READ_GITFILE_ERR_READ_FAILED:
 551                         die("Error reading %s", path);
 552                 case READ_GITFILE_ERR_INVALID_FORMAT:
 553                         die("Invalid gitfile format: %s", path);
 554                 case READ_GITFILE_ERR_NO_PATH:
 555                         die("No path in gitfile: %s", path);
 556                 case READ_GITFILE_ERR_NOT_A_REPO:
 557                         die("Not a git repository: %s", dir);
 558                 default:
 559                         assert(0);
 560                 }
 561         }
 562
 563         free(buf);
 564         return error_code ? NULL : path;
 565 }
 566
 567 static const char *setup_explicit_git_dir(const char *gitdirenv,
 568                                           struct strbuf *cwd,
 569                                           int *nongit_ok)
 570 {
 571         const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 572         const char *worktree;
 573         char *gitfile;
 574         int offset;
 575
 576         if (PATH_MAX - 40 < strlen(gitdirenv))
 577                 die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 578
 579         gitfile = (char*)read_gitfile(gitdirenv);
 580         if (gitfile) {
 581                 gitfile = xstrdup(gitfile);
 582                 gitdirenv = gitfile;
 583         }
 584
 585         if (!is_git_directory(gitdirenv)) {
 586                 if (nongit_ok) {
 587                         *nongit_ok = 1;
 588                         free(gitfile);
 589                         return NULL;
 590                 }
 591                 die("Not a git repository: '%s'", gitdirenv);
 592         }
 593
 594         if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 595                 free(gitfile);
 596                 return NULL;
 597         }
 598
 599         /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 600         if (work_tree_env)
 601                 set_git_work_tree(work_tree_env);
 602         else if (is_bare_repository_cfg > 0) {
 603                 if (git_work_tree_cfg) {
 604                         /* #22.2, #30 */
 605                         warning("core.bare and core.worktree do not make sense");
 606                         work_tree_config_is_bogus = 1;
 607                 }
 608
 609                 /* #18, #26 */
 610                 set_git_dir(gitdirenv);
 611                 free(gitfile);
 612                 return NULL;
 613         }
 614         else if (git_work_tree_cfg) { /* #6, #14 */
 615                 if (is_absolute_path(git_work_tree_cfg))
 616                         set_git_work_tree(git_work_tree_cfg);
 617                 else {
 618                         char *core_worktree;
 619                         if (chdir(gitdirenv))
 620                                 die_errno("Could not chdir to '%s'", gitdirenv);
 621                         if (chdir(git_work_tree_cfg))
 622                                 die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 623                         core_worktree = xgetcwd();
 624                         if (chdir(cwd->buf))
 625                                 die_errno("Could not come back to cwd");
 626                         set_git_work_tree(core_worktree);
 627                         free(core_worktree);
 628                 }
 629         }
 630         else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 631                 /* #16d */
 632                 set_git_dir(gitdirenv);
 633                 free(gitfile);
 634                 return NULL;
 635         }
 636         else /* #2, #10 */
 637                 set_git_work_tree(".");
 638
 639         /* set_git_work_tree() must have been called by now */
 640         worktree = get_git_work_tree();
 641
 642         /* both get_git_work_tree() and cwd are already normalized */
 643         if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */
 644                 set_git_dir(gitdirenv);
 645                 free(gitfile);
 646                 return NULL;
 647         }
 648
 649         offset = dir_inside_of(cwd->buf, worktree);
 650         if (offset >= 0) {      /* cwd inside worktree? */
 651                 set_git_dir(real_path(gitdirenv));
 652                 if (chdir(worktree))
 653                         die_errno("Could not chdir to '%s'", worktree);
 654                 strbuf_addch(cwd, '/');
 655                 free(gitfile);
 656                 return cwd->buf + offset;
 657         }
 658
 659         /* cwd outside worktree */
 660         set_git_dir(gitdirenv);
 661         free(gitfile);
 662         return NULL;
 663 }
 664
 665 static const char *setup_discovered_git_dir(const char *gitdir,
 666                                             struct strbuf *cwd, int offset,
 667                                             int *nongit_ok)
 668 {
 669         if (check_repository_format_gently(gitdir, nongit_ok))
 670                 return NULL;
 671
 672         /* --work-tree is set without --git-dir; use discovered one */
 673         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 674                 if (offset != cwd->len && !is_absolute_path(gitdir))
 675                         gitdir = xstrdup(real_path(gitdir));
 676                 if (chdir(cwd->buf))
 677                         die_errno("Could not come back to cwd");
 678                 return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 679         }
 680
 681         /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 682         if (is_bare_repository_cfg > 0) {
 683                 set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));
 684                 if (chdir(cwd->buf))
 685                         die_errno("Could not come back to cwd");
 686                 return NULL;
 687         }
 688
 689         /* #0, #1, #5, #8, #9, #12, #13 */
 690         set_git_work_tree(".");
 691         if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 692                 set_git_dir(gitdir);
 693         inside_git_dir = 0;
 694         inside_work_tree = 1;
 695         if (offset == cwd->len)
 696                 return NULL;
 697
 698         /* Make "offset" point to past the '/', and add a '/' at the end */
 699         offset++;
 700         strbuf_addch(cwd, '/');
 701         return cwd->buf + offset;
 702 }
 703
 704 /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 705 static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
 706                                       int *nongit_ok)
 707 {
 708         int root_len;
 709
 710         if (check_repository_format_gently(".", nongit_ok))
 711                 return NULL;
 712
 713         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 714
 715         /* --work-tree is set without --git-dir; use discovered one */
 716         if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 717                 const char *gitdir;
 718
 719                 gitdir = offset == cwd->len ? "." : xmemdupz(cwd->buf, offset);
 720                 if (chdir(cwd->buf))
 721                         die_errno("Could not come back to cwd");
 722                 return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 723         }
 724
 725         inside_git_dir = 1;
 726         inside_work_tree = 0;
 727         if (offset != cwd->len) {
 728                 if (chdir(cwd->buf))
 729                         die_errno("Cannot come back to cwd");
 730                 root_len = offset_1st_component(cwd->buf);
 731                 strbuf_setlen(cwd, offset > root_len ? offset : root_len);
 732                 set_git_dir(cwd->buf);
 733         }
 734         else
 735                 set_git_dir(".");
 736         return NULL;
 737 }
 738
 739 static const char *setup_nongit(const char *cwd, int *nongit_ok)
 740 {
 741         if (!nongit_ok)
 742                 die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 743         if (chdir(cwd))
 744                 die_errno("Cannot come back to cwd");
 745         *nongit_ok = 1;
 746         return NULL;
 747 }
 748
 749 static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 750 {
 751         struct stat buf;
 752         if (stat(path, &buf)) {
 753                 die_errno("failed to stat '%*s%s%s'",
 754                                 prefix_len,
 755                                 prefix ? prefix : "",
 756                                 prefix ? "/" : "", path);
 757         }
 758         return buf.st_dev;
 759 }
 760
 761 /*
 762  * A "string_list_each_func_t" function that canonicalizes an entry
 763  * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 764  * discards it if unusable.  The presence of an empty entry in
 765  * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 766  * subsequent entries.
 767  */
 768 static int canonicalize_ceiling_entry(struct string_list_item *item,
 769                                       void *cb_data)
 770 {
 771         int *empty_entry_found = cb_data;
 772         char *ceil = item->string;
 773
 774         if (!*ceil) {
 775                 *empty_entry_found = 1;
 776                 return 0;
 777         } else if (!is_absolute_path(ceil)) {
 778                 return 0;
 779         } else if (*empty_entry_found) {
 780                 /* Keep entry but do not canonicalize it */
 781                 return 1;
 782         } else {
 783                 const char *real_path = real_path_if_valid(ceil);
 784                 if (!real_path)
 785                         return 0;
 786                 free(item->string);
 787                 item->string = xstrdup(real_path);
 788                 return 1;
 789         }
 790 }
 791
 792 /*
 793  * We cannot decide in this function whether we are in the work tree or
 794  * not, since the config can only be read _after_ this function was called.
 795  */
 796 static const char *setup_git_directory_gently_1(int *nongit_ok)
 797 {
 798         const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 799         struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 800         static struct strbuf cwd = STRBUF_INIT;
 801         const char *gitdirenv, *ret;
 802         char *gitfile;
 803         int offset, offset_parent, ceil_offset = -1;
 804         dev_t current_device = 0;
 805         int one_filesystem = 1;
 806
 807         /*
 808          * We may have read an incomplete configuration before
 809          * setting-up the git directory. If so, clear the cache so
 810          * that the next queries to the configuration reload complete
 811          * configuration (including the per-repo config file that we
 812          * ignored previously).
 813          */
 814         git_config_clear();
 815
 816         /*
 817          * Let's assume that we are in a git repository.
 818          * If it turns out later that we are somewhere else, the value will be
 819          * updated accordingly.
 820          */
 821         if (nongit_ok)
 822                 *nongit_ok = 0;
 823
 824         if (strbuf_getcwd(&cwd))
 825                 die_errno("Unable to read current working directory");
 826         offset = cwd.len;
 827
 828         /*
 829          * If GIT_DIR is set explicitly, we're not going
 830          * to do any discovery, but we still do repository
 831          * validation.
 832          */
 833         gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 834         if (gitdirenv)
 835                 return setup_explicit_git_dir(gitdirenv, &cwd, nongit_ok);
 836
 837         if (env_ceiling_dirs) {
 838                 int empty_entry_found = 0;
 839
 840                 string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 841                 filter_string_list(&ceiling_dirs, 0,
 842                                    canonicalize_ceiling_entry, &empty_entry_found);
 843                 ceil_offset = longest_ancestor_length(cwd.buf, &ceiling_dirs);
 844                 string_list_clear(&ceiling_dirs, 0);
 845         }
 846
 847         if (ceil_offset < 0 && has_dos_drive_prefix(cwd.buf))
 848                 ceil_offset = 1;
 849
 850         /*
 851          * Test in the following order (relative to the cwd):
 852          * - .git (file containing "gitdir: <path>")
 853          * - .git/
 854          * - ./ (bare)
 855          * - ../.git
 856          * - ../.git/
 857          * - ../ (bare)
 858          * - ../../.git/
 859          *   etc.
 860          */
 861         one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 862         if (one_filesystem)
 863                 current_device = get_device_or_die(".", NULL, 0);
 864         for (;;) {
 865                 gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 866                 if (gitfile)
 867                         gitdirenv = gitfile = xstrdup(gitfile);
 868                 else {
 869                         if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 870                                 gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 871                 }
 872
 873                 if (gitdirenv) {
 874                         ret = setup_discovered_git_dir(gitdirenv,
 875                                                        &cwd, offset,
 876                                                        nongit_ok);
 877                         free(gitfile);
 878                         return ret;
 879                 }
 880                 free(gitfile);
 881
 882                 if (is_git_directory("."))
 883                         return setup_bare_git_dir(&cwd, offset, nongit_ok);
 884
 885                 offset_parent = offset;
 886                 while (--offset_parent > ceil_offset && cwd.buf[offset_parent] != '/');
 887                 if (offset_parent <= ceil_offset)
 888                         return setup_nongit(cwd.buf, nongit_ok);
 889                 if (one_filesystem) {
 890                         dev_t parent_device = get_device_or_die("..", cwd.buf,
 891                                                                 offset);
 892                         if (parent_device != current_device) {
 893                                 if (nongit_ok) {
 894                                         if (chdir(cwd.buf))
 895                                                 die_errno("Cannot come back to cwd");
 896                                         *nongit_ok = 1;
 897                                         return NULL;
 898                                 }
 899                                 strbuf_setlen(&cwd, offset);
 900                                 die("Not a git repository (or any parent up to mount point %s)\n"
 901                                 "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).",
 902                                     cwd.buf);
 903                         }
 904                 }
 905                 if (chdir("..")) {
 906                         strbuf_setlen(&cwd, offset);
 907                         die_errno("Cannot change to '%s/..'", cwd.buf);
 908                 }
 909                 offset = offset_parent;
 910         }
 911 }
 912
 913 const char *setup_git_directory_gently(int *nongit_ok)
 914 {
 915         const char *prefix;
 916
 917         prefix = setup_git_directory_gently_1(nongit_ok);
 918         if (prefix)
 919                 setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 920         else
 921                 setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 922
 923         if (startup_info) {
 924                 startup_info->have_repository = !nongit_ok || !*nongit_ok;
 925                 startup_info->prefix = prefix;
 926         }
 927         return prefix;
 928 }
 929
 930 int git_config_perm(const char *var, const char *value)
 931 {
 932         int i;
 933         char *endptr;
 934
 935         if (value == NULL)
 936                 return PERM_GROUP;
 937
 938         if (!strcmp(value, "umask"))
 939                 return PERM_UMASK;
 940         if (!strcmp(value, "group"))
 941                 return PERM_GROUP;
 942         if (!strcmp(value, "all") ||
 943             !strcmp(value, "world") ||
 944             !strcmp(value, "everybody"))
 945                 return PERM_EVERYBODY;
 946
 947         /* Parse octal numbers */
 948         i = strtol(value, &endptr, 8);
 949
 950         /* If not an octal number, maybe true/false? */
 951         if (*endptr != 0)
 952                 return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 953
 954         /*
 955          * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 956          * a chmod value to restrict to.
 957          */
 958         switch (i) {
 959         case PERM_UMASK:               /* 0 */
 960                 return PERM_UMASK;
 961         case OLD_PERM_GROUP:           /* 1 */
 962                 return PERM_GROUP;
 963         case OLD_PERM_EVERYBODY:       /* 2 */
 964                 return PERM_EVERYBODY;
 965         }
 966
 967         /* A filemode value was given: 0xxx */
 968
 969         if ((i & 0600) != 0600)
 970                 die("Problem with core.sharedRepository filemode value "
 971                     "(0%.3o).\nThe owner of files must always have "
 972                     "read and write permissions.", i);
 973
 974         /*
 975          * Mask filemode value. Others can not get write permission.
 976          * x flags for directories are handled separately.
 977          */
 978         return -(i & 0666);
 979 }
 980
 981 int check_repository_format_version(const char *var, const char *value, void *cb)
 982 {
 983         int ret = check_repo_format(var, value, cb);
 984         if (ret)
 985                 return ret;
 986         if (strcmp(var, "core.bare") == 0) {
 987                 is_bare_repository_cfg = git_config_bool(var, value);
 988                 if (is_bare_repository_cfg == 1)
 989                         inside_work_tree = -1;
 990         } else if (strcmp(var, "core.worktree") == 0) {
 991                 if (!value)
 992                         return config_error_nonbool(var);
 993                 free(git_work_tree_cfg);
 994                 git_work_tree_cfg = xstrdup(value);
 995                 inside_work_tree = -1;
 996         }
 997         return 0;
 998 }
 999
1000 int check_repository_format(void)
1001 {
1002         return check_repository_format_gently(get_git_dir(), NULL);
1003 }
1004
1005 /*
1006  * Returns the "prefix", a path to the current working directory
1007  * relative to the work tree root, or NULL, if the current working
1008  * directory is not a strict subdirectory of the work tree root. The
1009  * prefix always ends with a '/' character.
1010  */
1011 const char *setup_git_directory(void)
1012 {
1013         return setup_git_directory_gently(NULL);
1014 }
1015
1016 const char *resolve_gitdir(const char *suspect)
1017 {
1018         if (is_git_directory(suspect))
1019                 return suspect;
1020         return read_gitfile(suspect);
1021 }
1022
1023 /* if any standard file descriptor is missing open it to /dev/null */
1024 void sanitize_stdfds(void)
1025 {
1026         int fd = open("/dev/null", O_RDWR, 0);
1027         while (fd != -1 && fd < 2)
1028                 fd = dup(fd);
1029         if (fd == -1)
1030                 die_errno("open /dev/null or dup failed");
1031         if (fd > 2)
1032                 close(fd);
1033 }
1034
1035 int daemonize(void)
1036 {
1037 #ifdef NO_POSIX_GOODIES
1038         errno = ENOSYS;
1039         return -1;
1040 #else
1041         switch (fork()) {
1042                 case 0:
1043                         break;
1044                 case -1:
1045                         die_errno("fork failed");
1046                 default:
1047                         exit(0);
1048         }
1049         if (setsid() == -1)
1050                 die_errno("setsid failed");
1051         close(0);
1052         close(1);
1053         close(2);
1054         sanitize_stdfds();
1055         return 0;
1056 #endif
1057 }