00a23e6edf454bce0a30783e57195f251c1e1e11
   1#include "cache.h"
   2#include "dir.h"
   3#include "string-list.h"
   4
   5static int inside_git_dir = -1;
   6static int inside_work_tree = -1;
   7
   8/*
   9 * The input parameter must contain an absolute path, and it must already be
  10 * normalized.
  11 *
  12 * Find the part of an absolute path that lies inside the work tree by
  13 * dereferencing symlinks outside the work tree, for example:
  14 * /dir1/repo/dir2/file   (work tree is /dir1/repo)      -> dir2/file
  15 * /dir/file              (work tree is /)               -> dir/file
  16 * /dir/symlink1/symlink2 (symlink1 points to work tree) -> symlink2
  17 * /dir/repolink/file     (repolink points to /dir/repo) -> file
  18 * /dir/repo              (exactly equal to work tree)   -> (empty string)
  19 */
  20static int abspath_part_inside_repo(char *path)
  21{
  22        size_t len;
  23        size_t wtlen;
  24        char *path0;
  25        int off;
  26        const char *work_tree = get_git_work_tree();
  27
  28        if (!work_tree)
  29                return -1;
  30        wtlen = strlen(work_tree);
  31        len = strlen(path);
  32        off = offset_1st_component(path);
  33
  34        /* check if work tree is already the prefix */
  35        if (wtlen <= len && !strncmp(path, work_tree, wtlen)) {
  36                if (path[wtlen] == '/') {
  37                        memmove(path, path + wtlen + 1, len - wtlen);
  38                        return 0;
  39                } else if (path[wtlen - 1] == '/' || path[wtlen] == '\0') {
  40                        /* work tree is the root, or the whole path */
  41                        memmove(path, path + wtlen, len - wtlen + 1);
  42                        return 0;
  43                }
  44                /* work tree might match beginning of a symlink to work tree */
  45                off = wtlen;
  46        }
  47        path0 = path;
  48        path += off;
  49
  50        /* check each '/'-terminated level */
  51        while (*path) {
  52                path++;
  53                if (*path == '/') {
  54                        *path = '\0';
  55                        if (strcmp(real_path(path0), work_tree) == 0) {
  56                                memmove(path0, path + 1, len - (path - path0));
  57                                return 0;
  58                        }
  59                        *path = '/';
  60                }
  61        }
  62
  63        /* check whole path */
  64        if (strcmp(real_path(path0), work_tree) == 0) {
  65                *path0 = '\0';
  66                return 0;
  67        }
  68
  69        return -1;
  70}
  71
  72/*
  73 * Normalize "path", prepending the "prefix" for relative paths. If
  74 * remaining_prefix is not NULL, return the actual prefix still
  75 * remains in the path. For example, prefix = sub1/sub2/ and path is
  76 *
  77 *  foo          -> sub1/sub2/foo  (full prefix)
  78 *  ../foo       -> sub1/foo       (remaining prefix is sub1/)
  79 *  ../../bar    -> bar            (no remaining prefix)
  80 *  ../../sub1/sub2/foo -> sub1/sub2/foo (but no remaining prefix)
  81 *  `pwd`/../bar -> sub1/bar       (no remaining prefix)
  82 */
  83char *prefix_path_gently(const char *prefix, int len,
  84                         int *remaining_prefix, const char *path)
  85{
  86        const char *orig = path;
  87        char *sanitized;
  88        if (is_absolute_path(orig)) {
  89                sanitized = xmalloc(strlen(path) + 1);
  90                if (remaining_prefix)
  91                        *remaining_prefix = 0;
  92                if (normalize_path_copy_len(sanitized, path, remaining_prefix)) {
  93                        free(sanitized);
  94                        return NULL;
  95                }
  96                if (abspath_part_inside_repo(sanitized)) {
  97                        free(sanitized);
  98                        return NULL;
  99                }
 100        } else {
 101                sanitized = xmalloc(len + strlen(path) + 1);
 102                if (len)
 103                        memcpy(sanitized, prefix, len);
 104                strcpy(sanitized + len, path);
 105                if (remaining_prefix)
 106                        *remaining_prefix = len;
 107                if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix)) {
 108                        free(sanitized);
 109                        return NULL;
 110                }
 111        }
 112        return sanitized;
 113}
 114
 115char *prefix_path(const char *prefix, int len, const char *path)
 116{
 117        char *r = prefix_path_gently(prefix, len, NULL, path);
 118        if (!r)
 119                die("'%s' is outside repository", path);
 120        return r;
 121}
 122
 123int path_inside_repo(const char *prefix, const char *path)
 124{
 125        int len = prefix ? strlen(prefix) : 0;
 126        char *r = prefix_path_gently(prefix, len, NULL, path);
 127        if (r) {
 128                free(r);
 129                return 1;
 130        }
 131        return 0;
 132}
 133
 134int check_filename(const char *prefix, const char *arg)
 135{
 136        const char *name;
 137        struct stat st;
 138
 139        if (starts_with(arg, ":/")) {
 140                if (arg[2] == '\0') /* ":/" is root dir, always exists */
 141                        return 1;
 142                name = arg + 2;
 143        } else if (prefix)
 144                name = prefix_filename(prefix, strlen(prefix), arg);
 145        else
 146                name = arg;
 147        if (!lstat(name, &st))
 148                return 1; /* file exists */
 149        if (errno == ENOENT || errno == ENOTDIR)
 150                return 0; /* file does not exist */
 151        die_errno("failed to stat '%s'", arg);
 152}
 153
 154static void NORETURN die_verify_filename(const char *prefix,
 155                                         const char *arg,
 156                                         int diagnose_misspelt_rev)
 157{
 158        if (!diagnose_misspelt_rev)
 159                die("%s: no such path in the working tree.\n"
 160                    "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
 161                    arg);
 162        /*
 163         * Saying "'(icase)foo' does not exist in the index" when the
 164         * user gave us ":(icase)foo" is just stupid.  A magic pathspec
 165         * begins with a colon and is followed by a non-alnum; do not
 166         * let maybe_die_on_misspelt_object_name() even trigger.
 167         */
 168        if (!(arg[0] == ':' && !isalnum(arg[1])))
 169                maybe_die_on_misspelt_object_name(arg, prefix);
 170
 171        /* ... or fall back the most general message. */
 172        die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 173            "Use '--' to separate paths from revisions, like this:\n"
 174            "'git <command> [<revision>...] -- [<file>...]'", arg);
 175
 176}
 177
 178/*
 179 * Verify a filename that we got as an argument for a pathspec
 180 * entry. Note that a filename that begins with "-" never verifies
 181 * as true, because even if such a filename were to exist, we want
 182 * it to be preceded by the "--" marker (or we want the user to
 183 * use a format like "./-filename")
 184 *
 185 * The "diagnose_misspelt_rev" is used to provide a user-friendly
 186 * diagnosis when dying upon finding that "name" is not a pathname.
 187 * If set to 1, the diagnosis will try to diagnose "name" as an
 188 * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 189 * will only complain about an inexisting file.
 190 *
 191 * This function is typically called to check that a "file or rev"
 192 * argument is unambiguous. In this case, the caller will want
 193 * diagnose_misspelt_rev == 1 when verifying the first non-rev
 194 * argument (which could have been a revision), and
 195 * diagnose_misspelt_rev == 0 for the next ones (because we already
 196 * saw a filename, there's not ambiguity anymore).
 197 */
 198void verify_filename(const char *prefix,
 199                     const char *arg,
 200                     int diagnose_misspelt_rev)
 201{
 202        if (*arg == '-')
 203                die("bad flag '%s' used after filename", arg);
 204        if (check_filename(prefix, arg))
 205                return;
 206        die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 207}
 208
 209/*
 210 * Opposite of the above: the command line did not have -- marker
 211 * and we parsed the arg as a refname.  It should not be interpretable
 212 * as a filename.
 213 */
 214void verify_non_filename(const char *prefix, const char *arg)
 215{
 216        if (!is_inside_work_tree() || is_inside_git_dir())
 217                return;
 218        if (*arg == '-')
 219                return; /* flag */
 220        if (!check_filename(prefix, arg))
 221                return;
 222        die("ambiguous argument '%s': both revision and filename\n"
 223            "Use '--' to separate paths from revisions, like this:\n"
 224            "'git <command> [<revision>...] -- [<file>...]'", arg);
 225}
 226
 227static void get_common_dir(struct strbuf *sb, const char *gitdir)
 228{
 229        struct strbuf data = STRBUF_INIT;
 230        struct strbuf path = STRBUF_INIT;
 231        const char *git_common_dir = getenv(GIT_COMMON_DIR_ENVIRONMENT);
 232        if (git_common_dir) {
 233                strbuf_addstr(sb, git_common_dir);
 234                return;
 235        }
 236        strbuf_addf(&path, "%s/commondir", gitdir);
 237        if (file_exists(path.buf)) {
 238                if (strbuf_read_file(&data, path.buf, 0) <= 0)
 239                        die_errno(_("failed to read %s"), path.buf);
 240                while (data.len && (data.buf[data.len - 1] == '\n' ||
 241                                    data.buf[data.len - 1] == '\r'))
 242                        data.len--;
 243                data.buf[data.len] = '\0';
 244                strbuf_reset(&path);
 245                if (!is_absolute_path(data.buf))
 246                        strbuf_addf(&path, "%s/", gitdir);
 247                strbuf_addbuf(&path, &data);
 248                strbuf_addstr(sb, real_path(path.buf));
 249        } else
 250                strbuf_addstr(sb, gitdir);
 251        strbuf_release(&data);
 252        strbuf_release(&path);
 253}
 254
 255/*
 256 * Test if it looks like we're at a git directory.
 257 * We want to see:
 258 *
 259 *  - either an objects/ directory _or_ the proper
 260 *    GIT_OBJECT_DIRECTORY environment variable
 261 *  - a refs/ directory
 262 *  - either a HEAD symlink or a HEAD file that is formatted as
 263 *    a proper "ref:", or a regular file HEAD that has a properly
 264 *    formatted sha1 object name.
 265 */
 266int is_git_directory(const char *suspect)
 267{
 268        struct strbuf path = STRBUF_INIT;
 269        int ret = 0;
 270        size_t len;
 271
 272        /* Check worktree-related signatures */
 273        strbuf_addf(&path, "%s/HEAD", suspect);
 274        if (validate_headref(path.buf))
 275                goto done;
 276
 277        strbuf_reset(&path);
 278        get_common_dir(&path, suspect);
 279        len = path.len;
 280
 281        /* Check non-worktree-related signatures */
 282        if (getenv(DB_ENVIRONMENT)) {
 283                if (access(getenv(DB_ENVIRONMENT), X_OK))
 284                        goto done;
 285        }
 286        else {
 287                strbuf_setlen(&path, len);
 288                strbuf_addstr(&path, "/objects");
 289                if (access(path.buf, X_OK))
 290                        goto done;
 291        }
 292
 293        strbuf_setlen(&path, len);
 294        strbuf_addstr(&path, "/refs");
 295        if (access(path.buf, X_OK))
 296                goto done;
 297
 298        ret = 1;
 299done:
 300        strbuf_release(&path);
 301        return ret;
 302}
 303
 304int is_inside_git_dir(void)
 305{
 306        if (inside_git_dir < 0)
 307                inside_git_dir = is_inside_dir(get_git_dir());
 308        return inside_git_dir;
 309}
 310
 311int is_inside_work_tree(void)
 312{
 313        if (inside_work_tree < 0)
 314                inside_work_tree = is_inside_dir(get_git_work_tree());
 315        return inside_work_tree;
 316}
 317
 318void setup_work_tree(void)
 319{
 320        const char *work_tree, *git_dir;
 321        static int initialized = 0;
 322
 323        if (initialized)
 324                return;
 325        work_tree = get_git_work_tree();
 326        git_dir = get_git_dir();
 327        if (!is_absolute_path(git_dir))
 328                git_dir = real_path(get_git_dir());
 329        if (!work_tree || chdir(work_tree))
 330                die("This operation must be run in a work tree");
 331
 332        /*
 333         * Make sure subsequent git processes find correct worktree
 334         * if $GIT_WORK_TREE is set relative
 335         */
 336        if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 337                setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 338
 339        set_git_dir(remove_leading_path(git_dir, work_tree));
 340        initialized = 1;
 341}
 342
 343static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 344{
 345        struct strbuf sb = STRBUF_INIT;
 346        const char *repo_config;
 347        int ret = 0;
 348
 349        /*
 350         * git_config() can't be used here because it calls git_pathdup()
 351         * to get $GIT_CONFIG/config. That call will make setup_git_env()
 352         * set git_dir to ".git".
 353         *
 354         * We are in gitdir setup, no git dir has been found useable yet.
 355         * Use a gentler version of git_config() to check if this repo
 356         * is a good one.
 357         */
 358        strbuf_addf(&sb, "%s/config", gitdir);
 359        repo_config = sb.buf;
 360        git_config_early(check_repository_format_version, NULL, repo_config);
 361        if (GIT_REPO_VERSION < repository_format_version) {
 362                if (!nongit_ok)
 363                        die ("Expected git repo version <= %d, found %d",
 364                             GIT_REPO_VERSION, repository_format_version);
 365                warning("Expected git repo version <= %d, found %d",
 366                        GIT_REPO_VERSION, repository_format_version);
 367                warning("Please upgrade Git");
 368                *nongit_ok = -1;
 369                ret = -1;
 370        }
 371        strbuf_release(&sb);
 372        return ret;
 373}
 374
 375/*
 376 * Try to read the location of the git directory from the .git file,
 377 * return path to git directory if found.
 378 */
 379const char *read_gitfile(const char *path)
 380{
 381        char *buf;
 382        char *dir;
 383        const char *slash;
 384        struct stat st;
 385        int fd;
 386        ssize_t len;
 387
 388        if (stat(path, &st))
 389                return NULL;
 390        if (!S_ISREG(st.st_mode))
 391                return NULL;
 392        fd = open(path, O_RDONLY);
 393        if (fd < 0)
 394                die_errno("Error opening '%s'", path);
 395        buf = xmalloc(st.st_size + 1);
 396        len = read_in_full(fd, buf, st.st_size);
 397        close(fd);
 398        if (len != st.st_size)
 399                die("Error reading %s", path);
 400        buf[len] = '\0';
 401        if (!starts_with(buf, "gitdir: "))
 402                die("Invalid gitfile format: %s", path);
 403        while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 404                len--;
 405        if (len < 9)
 406                die("No path in gitfile: %s", path);
 407        buf[len] = '\0';
 408        dir = buf + 8;
 409
 410        if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 411                size_t pathlen = slash+1 - path;
 412                size_t dirlen = pathlen + len - 8;
 413                dir = xmalloc(dirlen + 1);
 414                strncpy(dir, path, pathlen);
 415                strncpy(dir + pathlen, buf + 8, len - 8);
 416                dir[dirlen] = '\0';
 417                free(buf);
 418                buf = dir;
 419        }
 420
 421        if (!is_git_directory(dir))
 422                die("Not a git repository: %s", dir);
 423        path = real_path(dir);
 424
 425        free(buf);
 426        return path;
 427}
 428
 429static const char *setup_explicit_git_dir(const char *gitdirenv,
 430                                          struct strbuf *cwd,
 431                                          int *nongit_ok)
 432{
 433        const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 434        const char *worktree;
 435        char *gitfile;
 436        int offset;
 437
 438        if (PATH_MAX - 40 < strlen(gitdirenv))
 439                die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 440
 441        gitfile = (char*)read_gitfile(gitdirenv);
 442        if (gitfile) {
 443                gitfile = xstrdup(gitfile);
 444                gitdirenv = gitfile;
 445        }
 446
 447        if (!is_git_directory(gitdirenv)) {
 448                if (nongit_ok) {
 449                        *nongit_ok = 1;
 450                        free(gitfile);
 451                        return NULL;
 452                }
 453                die("Not a git repository: '%s'", gitdirenv);
 454        }
 455
 456        if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 457                free(gitfile);
 458                return NULL;
 459        }
 460
 461        /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 462        if (work_tree_env)
 463                set_git_work_tree(work_tree_env);
 464        else if (is_bare_repository_cfg > 0) {
 465                if (git_work_tree_cfg) /* #22.2, #30 */
 466                        die("core.bare and core.worktree do not make sense");
 467
 468                /* #18, #26 */
 469                set_git_dir(gitdirenv);
 470                free(gitfile);
 471                return NULL;
 472        }
 473        else if (git_work_tree_cfg) { /* #6, #14 */
 474                if (is_absolute_path(git_work_tree_cfg))
 475                        set_git_work_tree(git_work_tree_cfg);
 476                else {
 477                        char *core_worktree;
 478                        if (chdir(gitdirenv))
 479                                die_errno("Could not chdir to '%s'", gitdirenv);
 480                        if (chdir(git_work_tree_cfg))
 481                                die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 482                        core_worktree = xgetcwd();
 483                        if (chdir(cwd->buf))
 484                                die_errno("Could not come back to cwd");
 485                        set_git_work_tree(core_worktree);
 486                        free(core_worktree);
 487                }
 488        }
 489        else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 490                /* #16d */
 491                set_git_dir(gitdirenv);
 492                free(gitfile);
 493                return NULL;
 494        }
 495        else /* #2, #10 */
 496                set_git_work_tree(".");
 497
 498        /* set_git_work_tree() must have been called by now */
 499        worktree = get_git_work_tree();
 500
 501        /* both get_git_work_tree() and cwd are already normalized */
 502        if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */
 503                set_git_dir(gitdirenv);
 504                free(gitfile);
 505                return NULL;
 506        }
 507
 508        offset = dir_inside_of(cwd->buf, worktree);
 509        if (offset >= 0) {      /* cwd inside worktree? */
 510                set_git_dir(real_path(gitdirenv));
 511                if (chdir(worktree))
 512                        die_errno("Could not chdir to '%s'", worktree);
 513                strbuf_addch(cwd, '/');
 514                free(gitfile);
 515                return cwd->buf + offset;
 516        }
 517
 518        /* cwd outside worktree */
 519        set_git_dir(gitdirenv);
 520        free(gitfile);
 521        return NULL;
 522}
 523
 524static const char *setup_discovered_git_dir(const char *gitdir,
 525                                            struct strbuf *cwd, int offset,
 526                                            int *nongit_ok)
 527{
 528        if (check_repository_format_gently(gitdir, nongit_ok))
 529                return NULL;
 530
 531        /* --work-tree is set without --git-dir; use discovered one */
 532        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 533                if (offset != cwd->len && !is_absolute_path(gitdir))
 534                        gitdir = xstrdup(real_path(gitdir));
 535                if (chdir(cwd->buf))
 536                        die_errno("Could not come back to cwd");
 537                return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 538        }
 539
 540        /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 541        if (is_bare_repository_cfg > 0) {
 542                set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));
 543                if (chdir(cwd->buf))
 544                        die_errno("Could not come back to cwd");
 545                return NULL;
 546        }
 547
 548        /* #0, #1, #5, #8, #9, #12, #13 */
 549        set_git_work_tree(".");
 550        if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 551                set_git_dir(gitdir);
 552        inside_git_dir = 0;
 553        inside_work_tree = 1;
 554        if (offset == cwd->len)
 555                return NULL;
 556
 557        /* Make "offset" point to past the '/', and add a '/' at the end */
 558        offset++;
 559        strbuf_addch(cwd, '/');
 560        return cwd->buf + offset;
 561}
 562
 563/* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 564static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
 565                                      int *nongit_ok)
 566{
 567        int root_len;
 568
 569        if (check_repository_format_gently(".", nongit_ok))
 570                return NULL;
 571
 572        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 573
 574        /* --work-tree is set without --git-dir; use discovered one */
 575        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 576                const char *gitdir;
 577
 578                gitdir = offset == cwd->len ? "." : xmemdupz(cwd->buf, offset);
 579                if (chdir(cwd->buf))
 580                        die_errno("Could not come back to cwd");
 581                return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 582        }
 583
 584        inside_git_dir = 1;
 585        inside_work_tree = 0;
 586        if (offset != cwd->len) {
 587                if (chdir(cwd->buf))
 588                        die_errno("Cannot come back to cwd");
 589                root_len = offset_1st_component(cwd->buf);
 590                strbuf_setlen(cwd, offset > root_len ? offset : root_len);
 591                set_git_dir(cwd->buf);
 592        }
 593        else
 594                set_git_dir(".");
 595        return NULL;
 596}
 597
 598static const char *setup_nongit(const char *cwd, int *nongit_ok)
 599{
 600        if (!nongit_ok)
 601                die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 602        if (chdir(cwd))
 603                die_errno("Cannot come back to cwd");
 604        *nongit_ok = 1;
 605        return NULL;
 606}
 607
 608static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 609{
 610        struct stat buf;
 611        if (stat(path, &buf)) {
 612                die_errno("failed to stat '%*s%s%s'",
 613                                prefix_len,
 614                                prefix ? prefix : "",
 615                                prefix ? "/" : "", path);
 616        }
 617        return buf.st_dev;
 618}
 619
 620/*
 621 * A "string_list_each_func_t" function that canonicalizes an entry
 622 * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 623 * discards it if unusable.  The presence of an empty entry in
 624 * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 625 * subsequent entries.
 626 */
 627static int canonicalize_ceiling_entry(struct string_list_item *item,
 628                                      void *cb_data)
 629{
 630        int *empty_entry_found = cb_data;
 631        char *ceil = item->string;
 632
 633        if (!*ceil) {
 634                *empty_entry_found = 1;
 635                return 0;
 636        } else if (!is_absolute_path(ceil)) {
 637                return 0;
 638        } else if (*empty_entry_found) {
 639                /* Keep entry but do not canonicalize it */
 640                return 1;
 641        } else {
 642                const char *real_path = real_path_if_valid(ceil);
 643                if (!real_path)
 644                        return 0;
 645                free(item->string);
 646                item->string = xstrdup(real_path);
 647                return 1;
 648        }
 649}
 650
 651/*
 652 * We cannot decide in this function whether we are in the work tree or
 653 * not, since the config can only be read _after_ this function was called.
 654 */
 655static const char *setup_git_directory_gently_1(int *nongit_ok)
 656{
 657        const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 658        struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 659        static struct strbuf cwd = STRBUF_INIT;
 660        const char *gitdirenv, *ret;
 661        char *gitfile;
 662        int offset, offset_parent, ceil_offset = -1;
 663        dev_t current_device = 0;
 664        int one_filesystem = 1;
 665
 666        /*
 667         * We may have read an incomplete configuration before
 668         * setting-up the git directory. If so, clear the cache so
 669         * that the next queries to the configuration reload complete
 670         * configuration (including the per-repo config file that we
 671         * ignored previously).
 672         */
 673        git_config_clear();
 674
 675        /*
 676         * Let's assume that we are in a git repository.
 677         * If it turns out later that we are somewhere else, the value will be
 678         * updated accordingly.
 679         */
 680        if (nongit_ok)
 681                *nongit_ok = 0;
 682
 683        if (strbuf_getcwd(&cwd))
 684                die_errno("Unable to read current working directory");
 685        offset = cwd.len;
 686
 687        /*
 688         * If GIT_DIR is set explicitly, we're not going
 689         * to do any discovery, but we still do repository
 690         * validation.
 691         */
 692        gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 693        if (gitdirenv)
 694                return setup_explicit_git_dir(gitdirenv, &cwd, nongit_ok);
 695
 696        if (env_ceiling_dirs) {
 697                int empty_entry_found = 0;
 698
 699                string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 700                filter_string_list(&ceiling_dirs, 0,
 701                                   canonicalize_ceiling_entry, &empty_entry_found);
 702                ceil_offset = longest_ancestor_length(cwd.buf, &ceiling_dirs);
 703                string_list_clear(&ceiling_dirs, 0);
 704        }
 705
 706        if (ceil_offset < 0 && has_dos_drive_prefix(cwd.buf))
 707                ceil_offset = 1;
 708
 709        /*
 710         * Test in the following order (relative to the cwd):
 711         * - .git (file containing "gitdir: <path>")
 712         * - .git/
 713         * - ./ (bare)
 714         * - ../.git
 715         * - ../.git/
 716         * - ../ (bare)
 717         * - ../../.git/
 718         *   etc.
 719         */
 720        one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 721        if (one_filesystem)
 722                current_device = get_device_or_die(".", NULL, 0);
 723        for (;;) {
 724                gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 725                if (gitfile)
 726                        gitdirenv = gitfile = xstrdup(gitfile);
 727                else {
 728                        if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 729                                gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 730                }
 731
 732                if (gitdirenv) {
 733                        ret = setup_discovered_git_dir(gitdirenv,
 734                                                       &cwd, offset,
 735                                                       nongit_ok);
 736                        free(gitfile);
 737                        return ret;
 738                }
 739                free(gitfile);
 740
 741                if (is_git_directory("."))
 742                        return setup_bare_git_dir(&cwd, offset, nongit_ok);
 743
 744                offset_parent = offset;
 745                while (--offset_parent > ceil_offset && cwd.buf[offset_parent] != '/');
 746                if (offset_parent <= ceil_offset)
 747                        return setup_nongit(cwd.buf, nongit_ok);
 748                if (one_filesystem) {
 749                        dev_t parent_device = get_device_or_die("..", cwd.buf,
 750                                                                offset);
 751                        if (parent_device != current_device) {
 752                                if (nongit_ok) {
 753                                        if (chdir(cwd.buf))
 754                                                die_errno("Cannot come back to cwd");
 755                                        *nongit_ok = 1;
 756                                        return NULL;
 757                                }
 758                                strbuf_setlen(&cwd, offset);
 759                                die("Not a git repository (or any parent up to mount point %s)\n"
 760                                "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).",
 761                                    cwd.buf);
 762                        }
 763                }
 764                if (chdir("..")) {
 765                        strbuf_setlen(&cwd, offset);
 766                        die_errno("Cannot change to '%s/..'", cwd.buf);
 767                }
 768                offset = offset_parent;
 769        }
 770}
 771
 772const char *setup_git_directory_gently(int *nongit_ok)
 773{
 774        const char *prefix;
 775
 776        prefix = setup_git_directory_gently_1(nongit_ok);
 777        if (prefix)
 778                setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 779        else
 780                setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 781
 782        if (startup_info) {
 783                startup_info->have_repository = !nongit_ok || !*nongit_ok;
 784                startup_info->prefix = prefix;
 785        }
 786        return prefix;
 787}
 788
 789int git_config_perm(const char *var, const char *value)
 790{
 791        int i;
 792        char *endptr;
 793
 794        if (value == NULL)
 795                return PERM_GROUP;
 796
 797        if (!strcmp(value, "umask"))
 798                return PERM_UMASK;
 799        if (!strcmp(value, "group"))
 800                return PERM_GROUP;
 801        if (!strcmp(value, "all") ||
 802            !strcmp(value, "world") ||
 803            !strcmp(value, "everybody"))
 804                return PERM_EVERYBODY;
 805
 806        /* Parse octal numbers */
 807        i = strtol(value, &endptr, 8);
 808
 809        /* If not an octal number, maybe true/false? */
 810        if (*endptr != 0)
 811                return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 812
 813        /*
 814         * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 815         * a chmod value to restrict to.
 816         */
 817        switch (i) {
 818        case PERM_UMASK:               /* 0 */
 819                return PERM_UMASK;
 820        case OLD_PERM_GROUP:           /* 1 */
 821                return PERM_GROUP;
 822        case OLD_PERM_EVERYBODY:       /* 2 */
 823                return PERM_EVERYBODY;
 824        }
 825
 826        /* A filemode value was given: 0xxx */
 827
 828        if ((i & 0600) != 0600)
 829                die("Problem with core.sharedRepository filemode value "
 830                    "(0%.3o).\nThe owner of files must always have "
 831                    "read and write permissions.", i);
 832
 833        /*
 834         * Mask filemode value. Others can not get write permission.
 835         * x flags for directories are handled separately.
 836         */
 837        return -(i & 0666);
 838}
 839
 840int check_repository_format_version(const char *var, const char *value, void *cb)
 841{
 842        if (strcmp(var, "core.repositoryformatversion") == 0)
 843                repository_format_version = git_config_int(var, value);
 844        else if (strcmp(var, "core.sharedrepository") == 0)
 845                shared_repository = git_config_perm(var, value);
 846        else if (strcmp(var, "core.bare") == 0) {
 847                is_bare_repository_cfg = git_config_bool(var, value);
 848                if (is_bare_repository_cfg == 1)
 849                        inside_work_tree = -1;
 850        } else if (strcmp(var, "core.worktree") == 0) {
 851                if (!value)
 852                        return config_error_nonbool(var);
 853                free(git_work_tree_cfg);
 854                git_work_tree_cfg = xstrdup(value);
 855                inside_work_tree = -1;
 856        }
 857        return 0;
 858}
 859
 860int check_repository_format(void)
 861{
 862        return check_repository_format_gently(get_git_dir(), NULL);
 863}
 864
 865/*
 866 * Returns the "prefix", a path to the current working directory
 867 * relative to the work tree root, or NULL, if the current working
 868 * directory is not a strict subdirectory of the work tree root. The
 869 * prefix always ends with a '/' character.
 870 */
 871const char *setup_git_directory(void)
 872{
 873        return setup_git_directory_gently(NULL);
 874}
 875
 876const char *resolve_gitdir(const char *suspect)
 877{
 878        if (is_git_directory(suspect))
 879                return suspect;
 880        return read_gitfile(suspect);
 881}
 882
 883/* if any standard file descriptor is missing open it to /dev/null */
 884void sanitize_stdfds(void)
 885{
 886        int fd = open("/dev/null", O_RDWR, 0);
 887        while (fd != -1 && fd < 2)
 888                fd = dup(fd);
 889        if (fd == -1)
 890                die_errno("open /dev/null or dup failed");
 891        if (fd > 2)
 892                close(fd);
 893}
 894
 895int daemonize(void)
 896{
 897#ifdef NO_POSIX_GOODIES
 898        errno = ENOSYS;
 899        return -1;
 900#else
 901        switch (fork()) {
 902                case 0:
 903                        break;
 904                case -1:
 905                        die_errno("fork failed");
 906                default:
 907                        exit(0);
 908        }
 909        if (setsid() == -1)
 910                die_errno("setsid failed");
 911        close(0);
 912        close(1);
 913        close(2);
 914        sanitize_stdfds();
 915        return 0;
 916#endif
 917}