setup.con commit setup: add gentle version of read_gitfile (a93beda)
   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 (!no_wildcard(arg))
 144                return 1;
 145        else if (prefix)
 146                name = prefix_filename(prefix, strlen(prefix), arg);
 147        else
 148                name = arg;
 149        if (!lstat(name, &st))
 150                return 1; /* file exists */
 151        if (errno == ENOENT || errno == ENOTDIR)
 152                return 0; /* file does not exist */
 153        die_errno("failed to stat '%s'", arg);
 154}
 155
 156static void NORETURN die_verify_filename(const char *prefix,
 157                                         const char *arg,
 158                                         int diagnose_misspelt_rev)
 159{
 160        if (!diagnose_misspelt_rev)
 161                die("%s: no such path in the working tree.\n"
 162                    "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
 163                    arg);
 164        /*
 165         * Saying "'(icase)foo' does not exist in the index" when the
 166         * user gave us ":(icase)foo" is just stupid.  A magic pathspec
 167         * begins with a colon and is followed by a non-alnum; do not
 168         * let maybe_die_on_misspelt_object_name() even trigger.
 169         */
 170        if (!(arg[0] == ':' && !isalnum(arg[1])))
 171                maybe_die_on_misspelt_object_name(arg, prefix);
 172
 173        /* ... or fall back the most general message. */
 174        die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 175            "Use '--' to separate paths from revisions, like this:\n"
 176            "'git <command> [<revision>...] -- [<file>...]'", arg);
 177
 178}
 179
 180/*
 181 * Verify a filename that we got as an argument for a pathspec
 182 * entry. Note that a filename that begins with "-" never verifies
 183 * as true, because even if such a filename were to exist, we want
 184 * it to be preceded by the "--" marker (or we want the user to
 185 * use a format like "./-filename")
 186 *
 187 * The "diagnose_misspelt_rev" is used to provide a user-friendly
 188 * diagnosis when dying upon finding that "name" is not a pathname.
 189 * If set to 1, the diagnosis will try to diagnose "name" as an
 190 * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 191 * will only complain about an inexisting file.
 192 *
 193 * This function is typically called to check that a "file or rev"
 194 * argument is unambiguous. In this case, the caller will want
 195 * diagnose_misspelt_rev == 1 when verifying the first non-rev
 196 * argument (which could have been a revision), and
 197 * diagnose_misspelt_rev == 0 for the next ones (because we already
 198 * saw a filename, there's not ambiguity anymore).
 199 */
 200void verify_filename(const char *prefix,
 201                     const char *arg,
 202                     int diagnose_misspelt_rev)
 203{
 204        if (*arg == '-')
 205                die("bad flag '%s' used after filename", arg);
 206        if (check_filename(prefix, arg))
 207                return;
 208        die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 209}
 210
 211/*
 212 * Opposite of the above: the command line did not have -- marker
 213 * and we parsed the arg as a refname.  It should not be interpretable
 214 * as a filename.
 215 */
 216void verify_non_filename(const char *prefix, const char *arg)
 217{
 218        if (!is_inside_work_tree() || is_inside_git_dir())
 219                return;
 220        if (*arg == '-')
 221                return; /* flag */
 222        if (!check_filename(prefix, arg))
 223                return;
 224        die("ambiguous argument '%s': both revision and filename\n"
 225            "Use '--' to separate paths from revisions, like this:\n"
 226            "'git <command> [<revision>...] -- [<file>...]'", arg);
 227}
 228
 229int get_common_dir(struct strbuf *sb, const char *gitdir)
 230{
 231        struct strbuf data = STRBUF_INIT;
 232        struct strbuf path = STRBUF_INIT;
 233        const char *git_common_dir = getenv(GIT_COMMON_DIR_ENVIRONMENT);
 234        int ret = 0;
 235        if (git_common_dir) {
 236                strbuf_addstr(sb, git_common_dir);
 237                return 1;
 238        }
 239        strbuf_addf(&path, "%s/commondir", gitdir);
 240        if (file_exists(path.buf)) {
 241                if (strbuf_read_file(&data, path.buf, 0) <= 0)
 242                        die_errno(_("failed to read %s"), path.buf);
 243                while (data.len && (data.buf[data.len - 1] == '\n' ||
 244                                    data.buf[data.len - 1] == '\r'))
 245                        data.len--;
 246                data.buf[data.len] = '\0';
 247                strbuf_reset(&path);
 248                if (!is_absolute_path(data.buf))
 249                        strbuf_addf(&path, "%s/", gitdir);
 250                strbuf_addbuf(&path, &data);
 251                strbuf_addstr(sb, real_path(path.buf));
 252                ret = 1;
 253        } else
 254                strbuf_addstr(sb, gitdir);
 255        strbuf_release(&data);
 256        strbuf_release(&path);
 257        return ret;
 258}
 259
 260/*
 261 * Test if it looks like we're at a git directory.
 262 * We want to see:
 263 *
 264 *  - either an objects/ directory _or_ the proper
 265 *    GIT_OBJECT_DIRECTORY environment variable
 266 *  - a refs/ directory
 267 *  - either a HEAD symlink or a HEAD file that is formatted as
 268 *    a proper "ref:", or a regular file HEAD that has a properly
 269 *    formatted sha1 object name.
 270 */
 271int is_git_directory(const char *suspect)
 272{
 273        struct strbuf path = STRBUF_INIT;
 274        int ret = 0;
 275        size_t len;
 276
 277        /* Check worktree-related signatures */
 278        strbuf_addf(&path, "%s/HEAD", suspect);
 279        if (validate_headref(path.buf))
 280                goto done;
 281
 282        strbuf_reset(&path);
 283        get_common_dir(&path, suspect);
 284        len = path.len;
 285
 286        /* Check non-worktree-related signatures */
 287        if (getenv(DB_ENVIRONMENT)) {
 288                if (access(getenv(DB_ENVIRONMENT), X_OK))
 289                        goto done;
 290        }
 291        else {
 292                strbuf_setlen(&path, len);
 293                strbuf_addstr(&path, "/objects");
 294                if (access(path.buf, X_OK))
 295                        goto done;
 296        }
 297
 298        strbuf_setlen(&path, len);
 299        strbuf_addstr(&path, "/refs");
 300        if (access(path.buf, X_OK))
 301                goto done;
 302
 303        ret = 1;
 304done:
 305        strbuf_release(&path);
 306        return ret;
 307}
 308
 309int is_inside_git_dir(void)
 310{
 311        if (inside_git_dir < 0)
 312                inside_git_dir = is_inside_dir(get_git_dir());
 313        return inside_git_dir;
 314}
 315
 316int is_inside_work_tree(void)
 317{
 318        if (inside_work_tree < 0)
 319                inside_work_tree = is_inside_dir(get_git_work_tree());
 320        return inside_work_tree;
 321}
 322
 323void setup_work_tree(void)
 324{
 325        const char *work_tree, *git_dir;
 326        static int initialized = 0;
 327
 328        if (initialized)
 329                return;
 330        work_tree = get_git_work_tree();
 331        git_dir = get_git_dir();
 332        if (!is_absolute_path(git_dir))
 333                git_dir = real_path(get_git_dir());
 334        if (!work_tree || chdir(work_tree))
 335                die("This operation must be run in a work tree");
 336
 337        /*
 338         * Make sure subsequent git processes find correct worktree
 339         * if $GIT_WORK_TREE is set relative
 340         */
 341        if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 342                setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 343
 344        set_git_dir(remove_leading_path(git_dir, work_tree));
 345        initialized = 1;
 346}
 347
 348static int check_repo_format(const char *var, const char *value, void *cb)
 349{
 350        if (strcmp(var, "core.repositoryformatversion") == 0)
 351                repository_format_version = git_config_int(var, value);
 352        else if (strcmp(var, "core.sharedrepository") == 0)
 353                shared_repository = git_config_perm(var, value);
 354        return 0;
 355}
 356
 357static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 358{
 359        struct strbuf sb = STRBUF_INIT;
 360        const char *repo_config;
 361        config_fn_t fn;
 362        int ret = 0;
 363
 364        if (get_common_dir(&sb, gitdir))
 365                fn = check_repo_format;
 366        else
 367                fn = check_repository_format_version;
 368        strbuf_addstr(&sb, "/config");
 369        repo_config = sb.buf;
 370
 371        /*
 372         * git_config() can't be used here because it calls git_pathdup()
 373         * to get $GIT_CONFIG/config. That call will make setup_git_env()
 374         * set git_dir to ".git".
 375         *
 376         * We are in gitdir setup, no git dir has been found useable yet.
 377         * Use a gentler version of git_config() to check if this repo
 378         * is a good one.
 379         */
 380        git_config_early(fn, NULL, repo_config);
 381        if (GIT_REPO_VERSION < repository_format_version) {
 382                if (!nongit_ok)
 383                        die ("Expected git repo version <= %d, found %d",
 384                             GIT_REPO_VERSION, repository_format_version);
 385                warning("Expected git repo version <= %d, found %d",
 386                        GIT_REPO_VERSION, repository_format_version);
 387                warning("Please upgrade Git");
 388                *nongit_ok = -1;
 389                ret = -1;
 390        }
 391        strbuf_release(&sb);
 392        return ret;
 393}
 394
 395static void update_linked_gitdir(const char *gitfile, const char *gitdir)
 396{
 397        struct strbuf path = STRBUF_INIT;
 398        struct stat st;
 399
 400        strbuf_addf(&path, "%s/gitfile", gitdir);
 401        if (stat(path.buf, &st) || st.st_mtime + 24 * 3600 < time(NULL))
 402                write_file(path.buf, 0, "%s\n", gitfile);
 403        strbuf_release(&path);
 404}
 405
 406/*
 407 * Try to read the location of the git directory from the .git file,
 408 * return path to git directory if found.
 409 *
 410 * On failure, if return_error_code is not NULL, return_error_code
 411 * will be set to an error code and NULL will be returned. If
 412 * return_error_code is NULL the function will die instead (for most
 413 * cases).
 414 */
 415const char *read_gitfile_gently(const char *path, int *return_error_code)
 416{
 417        int error_code = 0;
 418        char *buf = NULL;
 419        char *dir = NULL;
 420        const char *slash;
 421        struct stat st;
 422        int fd;
 423        ssize_t len;
 424
 425        if (stat(path, &st)) {
 426                error_code = READ_GITFILE_ERR_STAT_FAILED;
 427                goto cleanup_return;
 428        }
 429        if (!S_ISREG(st.st_mode)) {
 430                error_code = READ_GITFILE_ERR_NOT_A_FILE;
 431                goto cleanup_return;
 432        }
 433        fd = open(path, O_RDONLY);
 434        if (fd < 0) {
 435                error_code = READ_GITFILE_ERR_OPEN_FAILED;
 436                goto cleanup_return;
 437        }
 438        buf = xmalloc(st.st_size + 1);
 439        len = read_in_full(fd, buf, st.st_size);
 440        close(fd);
 441        if (len != st.st_size) {
 442                error_code = READ_GITFILE_ERR_READ_FAILED;
 443                goto cleanup_return;
 444        }
 445        buf[len] = '\0';
 446        if (!starts_with(buf, "gitdir: ")) {
 447                error_code = READ_GITFILE_ERR_INVALID_FORMAT;
 448                goto cleanup_return;
 449        }
 450        while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 451                len--;
 452        if (len < 9) {
 453                error_code = READ_GITFILE_ERR_NO_PATH;
 454                goto cleanup_return;
 455        }
 456        buf[len] = '\0';
 457        dir = buf + 8;
 458
 459        if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 460                size_t pathlen = slash+1 - path;
 461                size_t dirlen = pathlen + len - 8;
 462                dir = xmalloc(dirlen + 1);
 463                strncpy(dir, path, pathlen);
 464                strncpy(dir + pathlen, buf + 8, len - 8);
 465                dir[dirlen] = '\0';
 466                free(buf);
 467                buf = dir;
 468        }
 469        if (!is_git_directory(dir)) {
 470                error_code = READ_GITFILE_ERR_NOT_A_REPO;
 471                goto cleanup_return;
 472        }
 473        update_linked_gitdir(path, dir);
 474        path = real_path(dir);
 475
 476cleanup_return:
 477        free(buf);
 478
 479        if (return_error_code)
 480                *return_error_code = error_code;
 481
 482        if (error_code) {
 483                if (return_error_code)
 484                        return NULL;
 485
 486                switch (error_code) {
 487                case READ_GITFILE_ERR_STAT_FAILED:
 488                case READ_GITFILE_ERR_NOT_A_FILE:
 489                        return NULL;
 490                case READ_GITFILE_ERR_OPEN_FAILED:
 491                        die_errno("Error opening '%s'", path);
 492                case READ_GITFILE_ERR_READ_FAILED:
 493                        die("Error reading %s", path);
 494                case READ_GITFILE_ERR_INVALID_FORMAT:
 495                        die("Invalid gitfile format: %s", path);
 496                case READ_GITFILE_ERR_NO_PATH:
 497                        die("No path in gitfile: %s", path);
 498                case READ_GITFILE_ERR_NOT_A_REPO:
 499                        die("Not a git repository: %s", dir);
 500                default:
 501                        assert(0);
 502                }
 503        }
 504
 505        return path;
 506}
 507
 508static const char *setup_explicit_git_dir(const char *gitdirenv,
 509                                          struct strbuf *cwd,
 510                                          int *nongit_ok)
 511{
 512        const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 513        const char *worktree;
 514        char *gitfile;
 515        int offset;
 516
 517        if (PATH_MAX - 40 < strlen(gitdirenv))
 518                die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 519
 520        gitfile = (char*)read_gitfile(gitdirenv);
 521        if (gitfile) {
 522                gitfile = xstrdup(gitfile);
 523                gitdirenv = gitfile;
 524        }
 525
 526        if (!is_git_directory(gitdirenv)) {
 527                if (nongit_ok) {
 528                        *nongit_ok = 1;
 529                        free(gitfile);
 530                        return NULL;
 531                }
 532                die("Not a git repository: '%s'", gitdirenv);
 533        }
 534
 535        if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 536                free(gitfile);
 537                return NULL;
 538        }
 539
 540        /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 541        if (work_tree_env)
 542                set_git_work_tree(work_tree_env);
 543        else if (is_bare_repository_cfg > 0) {
 544                if (git_work_tree_cfg) /* #22.2, #30 */
 545                        die("core.bare and core.worktree do not make sense");
 546
 547                /* #18, #26 */
 548                set_git_dir(gitdirenv);
 549                free(gitfile);
 550                return NULL;
 551        }
 552        else if (git_work_tree_cfg) { /* #6, #14 */
 553                if (is_absolute_path(git_work_tree_cfg))
 554                        set_git_work_tree(git_work_tree_cfg);
 555                else {
 556                        char *core_worktree;
 557                        if (chdir(gitdirenv))
 558                                die_errno("Could not chdir to '%s'", gitdirenv);
 559                        if (chdir(git_work_tree_cfg))
 560                                die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 561                        core_worktree = xgetcwd();
 562                        if (chdir(cwd->buf))
 563                                die_errno("Could not come back to cwd");
 564                        set_git_work_tree(core_worktree);
 565                        free(core_worktree);
 566                }
 567        }
 568        else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 569                /* #16d */
 570                set_git_dir(gitdirenv);
 571                free(gitfile);
 572                return NULL;
 573        }
 574        else /* #2, #10 */
 575                set_git_work_tree(".");
 576
 577        /* set_git_work_tree() must have been called by now */
 578        worktree = get_git_work_tree();
 579
 580        /* both get_git_work_tree() and cwd are already normalized */
 581        if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */
 582                set_git_dir(gitdirenv);
 583                free(gitfile);
 584                return NULL;
 585        }
 586
 587        offset = dir_inside_of(cwd->buf, worktree);
 588        if (offset >= 0) {      /* cwd inside worktree? */
 589                set_git_dir(real_path(gitdirenv));
 590                if (chdir(worktree))
 591                        die_errno("Could not chdir to '%s'", worktree);
 592                strbuf_addch(cwd, '/');
 593                free(gitfile);
 594                return cwd->buf + offset;
 595        }
 596
 597        /* cwd outside worktree */
 598        set_git_dir(gitdirenv);
 599        free(gitfile);
 600        return NULL;
 601}
 602
 603static const char *setup_discovered_git_dir(const char *gitdir,
 604                                            struct strbuf *cwd, int offset,
 605                                            int *nongit_ok)
 606{
 607        if (check_repository_format_gently(gitdir, nongit_ok))
 608                return NULL;
 609
 610        /* --work-tree is set without --git-dir; use discovered one */
 611        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 612                if (offset != cwd->len && !is_absolute_path(gitdir))
 613                        gitdir = xstrdup(real_path(gitdir));
 614                if (chdir(cwd->buf))
 615                        die_errno("Could not come back to cwd");
 616                return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 617        }
 618
 619        /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 620        if (is_bare_repository_cfg > 0) {
 621                set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));
 622                if (chdir(cwd->buf))
 623                        die_errno("Could not come back to cwd");
 624                return NULL;
 625        }
 626
 627        /* #0, #1, #5, #8, #9, #12, #13 */
 628        set_git_work_tree(".");
 629        if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 630                set_git_dir(gitdir);
 631        inside_git_dir = 0;
 632        inside_work_tree = 1;
 633        if (offset == cwd->len)
 634                return NULL;
 635
 636        /* Make "offset" point to past the '/', and add a '/' at the end */
 637        offset++;
 638        strbuf_addch(cwd, '/');
 639        return cwd->buf + offset;
 640}
 641
 642/* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 643static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
 644                                      int *nongit_ok)
 645{
 646        int root_len;
 647
 648        if (check_repository_format_gently(".", nongit_ok))
 649                return NULL;
 650
 651        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 652
 653        /* --work-tree is set without --git-dir; use discovered one */
 654        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 655                const char *gitdir;
 656
 657                gitdir = offset == cwd->len ? "." : xmemdupz(cwd->buf, offset);
 658                if (chdir(cwd->buf))
 659                        die_errno("Could not come back to cwd");
 660                return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 661        }
 662
 663        inside_git_dir = 1;
 664        inside_work_tree = 0;
 665        if (offset != cwd->len) {
 666                if (chdir(cwd->buf))
 667                        die_errno("Cannot come back to cwd");
 668                root_len = offset_1st_component(cwd->buf);
 669                strbuf_setlen(cwd, offset > root_len ? offset : root_len);
 670                set_git_dir(cwd->buf);
 671        }
 672        else
 673                set_git_dir(".");
 674        return NULL;
 675}
 676
 677static const char *setup_nongit(const char *cwd, int *nongit_ok)
 678{
 679        if (!nongit_ok)
 680                die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 681        if (chdir(cwd))
 682                die_errno("Cannot come back to cwd");
 683        *nongit_ok = 1;
 684        return NULL;
 685}
 686
 687static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 688{
 689        struct stat buf;
 690        if (stat(path, &buf)) {
 691                die_errno("failed to stat '%*s%s%s'",
 692                                prefix_len,
 693                                prefix ? prefix : "",
 694                                prefix ? "/" : "", path);
 695        }
 696        return buf.st_dev;
 697}
 698
 699/*
 700 * A "string_list_each_func_t" function that canonicalizes an entry
 701 * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 702 * discards it if unusable.  The presence of an empty entry in
 703 * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 704 * subsequent entries.
 705 */
 706static int canonicalize_ceiling_entry(struct string_list_item *item,
 707                                      void *cb_data)
 708{
 709        int *empty_entry_found = cb_data;
 710        char *ceil = item->string;
 711
 712        if (!*ceil) {
 713                *empty_entry_found = 1;
 714                return 0;
 715        } else if (!is_absolute_path(ceil)) {
 716                return 0;
 717        } else if (*empty_entry_found) {
 718                /* Keep entry but do not canonicalize it */
 719                return 1;
 720        } else {
 721                const char *real_path = real_path_if_valid(ceil);
 722                if (!real_path)
 723                        return 0;
 724                free(item->string);
 725                item->string = xstrdup(real_path);
 726                return 1;
 727        }
 728}
 729
 730/*
 731 * We cannot decide in this function whether we are in the work tree or
 732 * not, since the config can only be read _after_ this function was called.
 733 */
 734static const char *setup_git_directory_gently_1(int *nongit_ok)
 735{
 736        const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 737        struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 738        static struct strbuf cwd = STRBUF_INIT;
 739        const char *gitdirenv, *ret;
 740        char *gitfile;
 741        int offset, offset_parent, ceil_offset = -1;
 742        dev_t current_device = 0;
 743        int one_filesystem = 1;
 744
 745        /*
 746         * We may have read an incomplete configuration before
 747         * setting-up the git directory. If so, clear the cache so
 748         * that the next queries to the configuration reload complete
 749         * configuration (including the per-repo config file that we
 750         * ignored previously).
 751         */
 752        git_config_clear();
 753
 754        /*
 755         * Let's assume that we are in a git repository.
 756         * If it turns out later that we are somewhere else, the value will be
 757         * updated accordingly.
 758         */
 759        if (nongit_ok)
 760                *nongit_ok = 0;
 761
 762        if (strbuf_getcwd(&cwd))
 763                die_errno("Unable to read current working directory");
 764        offset = cwd.len;
 765
 766        /*
 767         * If GIT_DIR is set explicitly, we're not going
 768         * to do any discovery, but we still do repository
 769         * validation.
 770         */
 771        gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 772        if (gitdirenv)
 773                return setup_explicit_git_dir(gitdirenv, &cwd, nongit_ok);
 774
 775        if (env_ceiling_dirs) {
 776                int empty_entry_found = 0;
 777
 778                string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 779                filter_string_list(&ceiling_dirs, 0,
 780                                   canonicalize_ceiling_entry, &empty_entry_found);
 781                ceil_offset = longest_ancestor_length(cwd.buf, &ceiling_dirs);
 782                string_list_clear(&ceiling_dirs, 0);
 783        }
 784
 785        if (ceil_offset < 0 && has_dos_drive_prefix(cwd.buf))
 786                ceil_offset = 1;
 787
 788        /*
 789         * Test in the following order (relative to the cwd):
 790         * - .git (file containing "gitdir: <path>")
 791         * - .git/
 792         * - ./ (bare)
 793         * - ../.git
 794         * - ../.git/
 795         * - ../ (bare)
 796         * - ../../.git/
 797         *   etc.
 798         */
 799        one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 800        if (one_filesystem)
 801                current_device = get_device_or_die(".", NULL, 0);
 802        for (;;) {
 803                gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 804                if (gitfile)
 805                        gitdirenv = gitfile = xstrdup(gitfile);
 806                else {
 807                        if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 808                                gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 809                }
 810
 811                if (gitdirenv) {
 812                        ret = setup_discovered_git_dir(gitdirenv,
 813                                                       &cwd, offset,
 814                                                       nongit_ok);
 815                        free(gitfile);
 816                        return ret;
 817                }
 818                free(gitfile);
 819
 820                if (is_git_directory("."))
 821                        return setup_bare_git_dir(&cwd, offset, nongit_ok);
 822
 823                offset_parent = offset;
 824                while (--offset_parent > ceil_offset && cwd.buf[offset_parent] != '/');
 825                if (offset_parent <= ceil_offset)
 826                        return setup_nongit(cwd.buf, nongit_ok);
 827                if (one_filesystem) {
 828                        dev_t parent_device = get_device_or_die("..", cwd.buf,
 829                                                                offset);
 830                        if (parent_device != current_device) {
 831                                if (nongit_ok) {
 832                                        if (chdir(cwd.buf))
 833                                                die_errno("Cannot come back to cwd");
 834                                        *nongit_ok = 1;
 835                                        return NULL;
 836                                }
 837                                strbuf_setlen(&cwd, offset);
 838                                die("Not a git repository (or any parent up to mount point %s)\n"
 839                                "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).",
 840                                    cwd.buf);
 841                        }
 842                }
 843                if (chdir("..")) {
 844                        strbuf_setlen(&cwd, offset);
 845                        die_errno("Cannot change to '%s/..'", cwd.buf);
 846                }
 847                offset = offset_parent;
 848        }
 849}
 850
 851const char *setup_git_directory_gently(int *nongit_ok)
 852{
 853        const char *prefix;
 854
 855        prefix = setup_git_directory_gently_1(nongit_ok);
 856        if (prefix)
 857                setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 858        else
 859                setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 860
 861        if (startup_info) {
 862                startup_info->have_repository = !nongit_ok || !*nongit_ok;
 863                startup_info->prefix = prefix;
 864        }
 865        return prefix;
 866}
 867
 868int git_config_perm(const char *var, const char *value)
 869{
 870        int i;
 871        char *endptr;
 872
 873        if (value == NULL)
 874                return PERM_GROUP;
 875
 876        if (!strcmp(value, "umask"))
 877                return PERM_UMASK;
 878        if (!strcmp(value, "group"))
 879                return PERM_GROUP;
 880        if (!strcmp(value, "all") ||
 881            !strcmp(value, "world") ||
 882            !strcmp(value, "everybody"))
 883                return PERM_EVERYBODY;
 884
 885        /* Parse octal numbers */
 886        i = strtol(value, &endptr, 8);
 887
 888        /* If not an octal number, maybe true/false? */
 889        if (*endptr != 0)
 890                return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 891
 892        /*
 893         * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 894         * a chmod value to restrict to.
 895         */
 896        switch (i) {
 897        case PERM_UMASK:               /* 0 */
 898                return PERM_UMASK;
 899        case OLD_PERM_GROUP:           /* 1 */
 900                return PERM_GROUP;
 901        case OLD_PERM_EVERYBODY:       /* 2 */
 902                return PERM_EVERYBODY;
 903        }
 904
 905        /* A filemode value was given: 0xxx */
 906
 907        if ((i & 0600) != 0600)
 908                die("Problem with core.sharedRepository filemode value "
 909                    "(0%.3o).\nThe owner of files must always have "
 910                    "read and write permissions.", i);
 911
 912        /*
 913         * Mask filemode value. Others can not get write permission.
 914         * x flags for directories are handled separately.
 915         */
 916        return -(i & 0666);
 917}
 918
 919int check_repository_format_version(const char *var, const char *value, void *cb)
 920{
 921        int ret = check_repo_format(var, value, cb);
 922        if (ret)
 923                return ret;
 924        if (strcmp(var, "core.bare") == 0) {
 925                is_bare_repository_cfg = git_config_bool(var, value);
 926                if (is_bare_repository_cfg == 1)
 927                        inside_work_tree = -1;
 928        } else if (strcmp(var, "core.worktree") == 0) {
 929                if (!value)
 930                        return config_error_nonbool(var);
 931                free(git_work_tree_cfg);
 932                git_work_tree_cfg = xstrdup(value);
 933                inside_work_tree = -1;
 934        }
 935        return 0;
 936}
 937
 938int check_repository_format(void)
 939{
 940        return check_repository_format_gently(get_git_dir(), NULL);
 941}
 942
 943/*
 944 * Returns the "prefix", a path to the current working directory
 945 * relative to the work tree root, or NULL, if the current working
 946 * directory is not a strict subdirectory of the work tree root. The
 947 * prefix always ends with a '/' character.
 948 */
 949const char *setup_git_directory(void)
 950{
 951        return setup_git_directory_gently(NULL);
 952}
 953
 954const char *resolve_gitdir(const char *suspect)
 955{
 956        if (is_git_directory(suspect))
 957                return suspect;
 958        return read_gitfile(suspect);
 959}
 960
 961/* if any standard file descriptor is missing open it to /dev/null */
 962void sanitize_stdfds(void)
 963{
 964        int fd = open("/dev/null", O_RDWR, 0);
 965        while (fd != -1 && fd < 2)
 966                fd = dup(fd);
 967        if (fd == -1)
 968                die_errno("open /dev/null or dup failed");
 969        if (fd > 2)
 970                close(fd);
 971}
 972
 973int daemonize(void)
 974{
 975#ifdef NO_POSIX_GOODIES
 976        errno = ENOSYS;
 977        return -1;
 978#else
 979        switch (fork()) {
 980                case 0:
 981                        break;
 982                case -1:
 983                        die_errno("fork failed");
 984                default:
 985                        exit(0);
 986        }
 987        if (setsid() == -1)
 988                die_errno("setsid failed");
 989        close(0);
 990        close(1);
 991        close(2);
 992        sanitize_stdfds();
 993        return 0;
 994#endif
 995}