setup.con commit unpack-trees.c: use error_errno() (43c728e)
   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;
   7static int work_tree_config_is_bogus;
   8static 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 */
  22static 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 */
  85char *prefix_path_gently(const char *prefix, int len,
  86                         int *remaining_prefix, const char *path)
  87{
  88        const char *orig = path;
  89        char *sanitized;
  90        if (is_absolute_path(orig)) {
  91                sanitized = xmallocz(strlen(path));
  92                if (remaining_prefix)
  93                        *remaining_prefix = 0;
  94                if (normalize_path_copy_len(sanitized, path, remaining_prefix)) {
  95                        free(sanitized);
  96                        return NULL;
  97                }
  98                if (abspath_part_inside_repo(sanitized)) {
  99                        free(sanitized);
 100                        return NULL;
 101                }
 102        } else {
 103                sanitized = xstrfmt("%.*s%s", len, prefix, path);
 104                if (remaining_prefix)
 105                        *remaining_prefix = len;
 106                if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix)) {
 107                        free(sanitized);
 108                        return NULL;
 109                }
 110        }
 111        return sanitized;
 112}
 113
 114char *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
 122int 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
 133int check_filename(const char *prefix, const char *arg)
 134{
 135        const char *name;
 136        struct stat st;
 137
 138        if (starts_with(arg, ":/")) {
 139                if (arg[2] == '\0') /* ":/" is root dir, always exists */
 140                        return 1;
 141                name = arg + 2;
 142        } else if (prefix)
 143                name = prefix_filename(prefix, strlen(prefix), arg);
 144        else
 145                name = arg;
 146        if (!lstat(name, &st))
 147                return 1; /* file exists */
 148        if (errno == ENOENT || errno == ENOTDIR)
 149                return 0; /* file does not exist */
 150        die_errno("failed to stat '%s'", arg);
 151}
 152
 153static void NORETURN die_verify_filename(const char *prefix,
 154                                         const char *arg,
 155                                         int diagnose_misspelt_rev)
 156{
 157        if (!diagnose_misspelt_rev)
 158                die("%s: no such path in the working tree.\n"
 159                    "Use 'git <command> -- <path>...' to specify paths that do not exist locally.",
 160                    arg);
 161        /*
 162         * Saying "'(icase)foo' does not exist in the index" when the
 163         * user gave us ":(icase)foo" is just stupid.  A magic pathspec
 164         * begins with a colon and is followed by a non-alnum; do not
 165         * let maybe_die_on_misspelt_object_name() even trigger.
 166         */
 167        if (!(arg[0] == ':' && !isalnum(arg[1])))
 168                maybe_die_on_misspelt_object_name(arg, prefix);
 169
 170        /* ... or fall back the most general message. */
 171        die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 172            "Use '--' to separate paths from revisions, like this:\n"
 173            "'git <command> [<revision>...] -- [<file>...]'", arg);
 174
 175}
 176
 177/*
 178 * Verify a filename that we got as an argument for a pathspec
 179 * entry. Note that a filename that begins with "-" never verifies
 180 * as true, because even if such a filename were to exist, we want
 181 * it to be preceded by the "--" marker (or we want the user to
 182 * use a format like "./-filename")
 183 *
 184 * The "diagnose_misspelt_rev" is used to provide a user-friendly
 185 * diagnosis when dying upon finding that "name" is not a pathname.
 186 * If set to 1, the diagnosis will try to diagnose "name" as an
 187 * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 188 * will only complain about an inexisting file.
 189 *
 190 * This function is typically called to check that a "file or rev"
 191 * argument is unambiguous. In this case, the caller will want
 192 * diagnose_misspelt_rev == 1 when verifying the first non-rev
 193 * argument (which could have been a revision), and
 194 * diagnose_misspelt_rev == 0 for the next ones (because we already
 195 * saw a filename, there's not ambiguity anymore).
 196 */
 197void verify_filename(const char *prefix,
 198                     const char *arg,
 199                     int diagnose_misspelt_rev)
 200{
 201        if (*arg == '-')
 202                die("bad flag '%s' used after filename", arg);
 203        if (check_filename(prefix, arg) || !no_wildcard(arg))
 204                return;
 205        die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 206}
 207
 208/*
 209 * Opposite of the above: the command line did not have -- marker
 210 * and we parsed the arg as a refname.  It should not be interpretable
 211 * as a filename.
 212 */
 213void verify_non_filename(const char *prefix, const char *arg)
 214{
 215        if (!is_inside_work_tree() || is_inside_git_dir())
 216                return;
 217        if (*arg == '-')
 218                return; /* flag */
 219        if (!check_filename(prefix, arg))
 220                return;
 221        die("ambiguous argument '%s': both revision and filename\n"
 222            "Use '--' to separate paths from revisions, like this:\n"
 223            "'git <command> [<revision>...] -- [<file>...]'", arg);
 224}
 225
 226int get_common_dir(struct strbuf *sb, const char *gitdir)
 227{
 228        const char *git_env_common_dir = getenv(GIT_COMMON_DIR_ENVIRONMENT);
 229        if (git_env_common_dir) {
 230                strbuf_addstr(sb, git_env_common_dir);
 231                return 1;
 232        } else {
 233                return get_common_dir_noenv(sb, gitdir);
 234        }
 235}
 236
 237int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
 238{
 239        struct strbuf data = STRBUF_INIT;
 240        struct strbuf path = STRBUF_INIT;
 241        int ret = 0;
 242
 243        strbuf_addf(&path, "%s/commondir", gitdir);
 244        if (file_exists(path.buf)) {
 245                if (strbuf_read_file(&data, path.buf, 0) <= 0)
 246                        die_errno(_("failed to read %s"), path.buf);
 247                while (data.len && (data.buf[data.len - 1] == '\n' ||
 248                                    data.buf[data.len - 1] == '\r'))
 249                        data.len--;
 250                data.buf[data.len] = '\0';
 251                strbuf_reset(&path);
 252                if (!is_absolute_path(data.buf))
 253                        strbuf_addf(&path, "%s/", gitdir);
 254                strbuf_addbuf(&path, &data);
 255                strbuf_addstr(sb, real_path(path.buf));
 256                ret = 1;
 257        } else
 258                strbuf_addstr(sb, gitdir);
 259        strbuf_release(&data);
 260        strbuf_release(&path);
 261        return ret;
 262}
 263
 264/*
 265 * Test if it looks like we're at a git directory.
 266 * We want to see:
 267 *
 268 *  - either an objects/ directory _or_ the proper
 269 *    GIT_OBJECT_DIRECTORY environment variable
 270 *  - a refs/ directory
 271 *  - either a HEAD symlink or a HEAD file that is formatted as
 272 *    a proper "ref:", or a regular file HEAD that has a properly
 273 *    formatted sha1 object name.
 274 */
 275int is_git_directory(const char *suspect)
 276{
 277        struct strbuf path = STRBUF_INIT;
 278        int ret = 0;
 279        size_t len;
 280
 281        /* Check worktree-related signatures */
 282        strbuf_addf(&path, "%s/HEAD", suspect);
 283        if (validate_headref(path.buf))
 284                goto done;
 285
 286        strbuf_reset(&path);
 287        get_common_dir(&path, suspect);
 288        len = path.len;
 289
 290        /* Check non-worktree-related signatures */
 291        if (getenv(DB_ENVIRONMENT)) {
 292                if (access(getenv(DB_ENVIRONMENT), X_OK))
 293                        goto done;
 294        }
 295        else {
 296                strbuf_setlen(&path, len);
 297                strbuf_addstr(&path, "/objects");
 298                if (access(path.buf, X_OK))
 299                        goto done;
 300        }
 301
 302        strbuf_setlen(&path, len);
 303        strbuf_addstr(&path, "/refs");
 304        if (access(path.buf, X_OK))
 305                goto done;
 306
 307        ret = 1;
 308done:
 309        strbuf_release(&path);
 310        return ret;
 311}
 312
 313int is_nonbare_repository_dir(struct strbuf *path)
 314{
 315        int ret = 0;
 316        int gitfile_error;
 317        size_t orig_path_len = path->len;
 318        assert(orig_path_len != 0);
 319        strbuf_complete(path, '/');
 320        strbuf_addstr(path, ".git");
 321        if (read_gitfile_gently(path->buf, &gitfile_error) || is_git_directory(path->buf))
 322                ret = 1;
 323        if (gitfile_error == READ_GITFILE_ERR_OPEN_FAILED ||
 324            gitfile_error == READ_GITFILE_ERR_READ_FAILED)
 325                ret = 1;
 326        strbuf_setlen(path, orig_path_len);
 327        return ret;
 328}
 329
 330int is_inside_git_dir(void)
 331{
 332        if (inside_git_dir < 0)
 333                inside_git_dir = is_inside_dir(get_git_dir());
 334        return inside_git_dir;
 335}
 336
 337int is_inside_work_tree(void)
 338{
 339        if (inside_work_tree < 0)
 340                inside_work_tree = is_inside_dir(get_git_work_tree());
 341        return inside_work_tree;
 342}
 343
 344void setup_work_tree(void)
 345{
 346        const char *work_tree, *git_dir;
 347        static int initialized = 0;
 348
 349        if (initialized)
 350                return;
 351
 352        if (work_tree_config_is_bogus)
 353                die("unable to set up work tree using invalid config");
 354
 355        work_tree = get_git_work_tree();
 356        git_dir = get_git_dir();
 357        if (!is_absolute_path(git_dir))
 358                git_dir = real_path(get_git_dir());
 359        if (!work_tree || chdir(work_tree))
 360                die("This operation must be run in a work tree");
 361
 362        /*
 363         * Make sure subsequent git processes find correct worktree
 364         * if $GIT_WORK_TREE is set relative
 365         */
 366        if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 367                setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 368
 369        set_git_dir(remove_leading_path(git_dir, work_tree));
 370        initialized = 1;
 371}
 372
 373static int check_repo_format(const char *var, const char *value, void *cb)
 374{
 375        const char *ext;
 376
 377        if (strcmp(var, "core.repositoryformatversion") == 0)
 378                repository_format_version = git_config_int(var, value);
 379        else if (strcmp(var, "core.sharedrepository") == 0)
 380                shared_repository = git_config_perm(var, value);
 381        else if (skip_prefix(var, "extensions.", &ext)) {
 382                /*
 383                 * record any known extensions here; otherwise,
 384                 * we fall through to recording it as unknown, and
 385                 * check_repository_format will complain
 386                 */
 387                if (!strcmp(ext, "noop"))
 388                        ;
 389                else if (!strcmp(ext, "preciousobjects"))
 390                        repository_format_precious_objects = git_config_bool(var, value);
 391                else
 392                        string_list_append(&unknown_extensions, ext);
 393        }
 394        return 0;
 395}
 396
 397static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 398{
 399        struct strbuf sb = STRBUF_INIT;
 400        const char *repo_config;
 401        config_fn_t fn;
 402        int ret = 0;
 403
 404        string_list_clear(&unknown_extensions, 0);
 405
 406        if (get_common_dir(&sb, gitdir))
 407                fn = check_repo_format;
 408        else
 409                fn = check_repository_format_version;
 410        strbuf_addstr(&sb, "/config");
 411        repo_config = sb.buf;
 412
 413        /*
 414         * git_config() can't be used here because it calls git_pathdup()
 415         * to get $GIT_CONFIG/config. That call will make setup_git_env()
 416         * set git_dir to ".git".
 417         *
 418         * We are in gitdir setup, no git dir has been found useable yet.
 419         * Use a gentler version of git_config() to check if this repo
 420         * is a good one.
 421         */
 422        git_config_early(fn, NULL, repo_config);
 423        if (GIT_REPO_VERSION_READ < repository_format_version) {
 424                if (!nongit_ok)
 425                        die ("Expected git repo version <= %d, found %d",
 426                             GIT_REPO_VERSION_READ, repository_format_version);
 427                warning("Expected git repo version <= %d, found %d",
 428                        GIT_REPO_VERSION_READ, repository_format_version);
 429                warning("Please upgrade Git");
 430                *nongit_ok = -1;
 431                ret = -1;
 432        }
 433
 434        if (repository_format_version >= 1 && unknown_extensions.nr) {
 435                int i;
 436
 437                if (!nongit_ok)
 438                        die("unknown repository extension: %s",
 439                            unknown_extensions.items[0].string);
 440
 441                for (i = 0; i < unknown_extensions.nr; i++)
 442                        warning("unknown repository extension: %s",
 443                                unknown_extensions.items[i].string);
 444                *nongit_ok = -1;
 445                ret = -1;
 446        }
 447
 448        strbuf_release(&sb);
 449        return ret;
 450}
 451
 452/*
 453 * Try to read the location of the git directory from the .git file,
 454 * return path to git directory if found.
 455 *
 456 * On failure, if return_error_code is not NULL, return_error_code
 457 * will be set to an error code and NULL will be returned. If
 458 * return_error_code is NULL the function will die instead (for most
 459 * cases).
 460 */
 461const char *read_gitfile_gently(const char *path, int *return_error_code)
 462{
 463        const int max_file_size = 1 << 20;  /* 1MB */
 464        int error_code = 0;
 465        char *buf = NULL;
 466        char *dir = NULL;
 467        const char *slash;
 468        struct stat st;
 469        int fd;
 470        ssize_t len;
 471
 472        if (stat(path, &st)) {
 473                error_code = READ_GITFILE_ERR_STAT_FAILED;
 474                goto cleanup_return;
 475        }
 476        if (!S_ISREG(st.st_mode)) {
 477                error_code = READ_GITFILE_ERR_NOT_A_FILE;
 478                goto cleanup_return;
 479        }
 480        if (st.st_size > max_file_size) {
 481                error_code = READ_GITFILE_ERR_TOO_LARGE;
 482                goto cleanup_return;
 483        }
 484        fd = open(path, O_RDONLY);
 485        if (fd < 0) {
 486                error_code = READ_GITFILE_ERR_OPEN_FAILED;
 487                goto cleanup_return;
 488        }
 489        buf = xmallocz(st.st_size);
 490        len = read_in_full(fd, buf, st.st_size);
 491        close(fd);
 492        if (len != st.st_size) {
 493                error_code = READ_GITFILE_ERR_READ_FAILED;
 494                goto cleanup_return;
 495        }
 496        if (!starts_with(buf, "gitdir: ")) {
 497                error_code = READ_GITFILE_ERR_INVALID_FORMAT;
 498                goto cleanup_return;
 499        }
 500        while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 501                len--;
 502        if (len < 9) {
 503                error_code = READ_GITFILE_ERR_NO_PATH;
 504                goto cleanup_return;
 505        }
 506        buf[len] = '\0';
 507        dir = buf + 8;
 508
 509        if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 510                size_t pathlen = slash+1 - path;
 511                dir = xstrfmt("%.*s%.*s", (int)pathlen, path,
 512                              (int)(len - 8), buf + 8);
 513                free(buf);
 514                buf = dir;
 515        }
 516        if (!is_git_directory(dir)) {
 517                error_code = READ_GITFILE_ERR_NOT_A_REPO;
 518                goto cleanup_return;
 519        }
 520        path = real_path(dir);
 521
 522cleanup_return:
 523        if (return_error_code)
 524                *return_error_code = error_code;
 525        else if (error_code) {
 526                switch (error_code) {
 527                case READ_GITFILE_ERR_STAT_FAILED:
 528                case READ_GITFILE_ERR_NOT_A_FILE:
 529                        /* non-fatal; follow return path */
 530                        break;
 531                case READ_GITFILE_ERR_OPEN_FAILED:
 532                        die_errno("Error opening '%s'", path);
 533                case READ_GITFILE_ERR_TOO_LARGE:
 534                        die("Too large to be a .git file: '%s'", path);
 535                case READ_GITFILE_ERR_READ_FAILED:
 536                        die("Error reading %s", path);
 537                case READ_GITFILE_ERR_INVALID_FORMAT:
 538                        die("Invalid gitfile format: %s", path);
 539                case READ_GITFILE_ERR_NO_PATH:
 540                        die("No path in gitfile: %s", path);
 541                case READ_GITFILE_ERR_NOT_A_REPO:
 542                        die("Not a git repository: %s", dir);
 543                default:
 544                        assert(0);
 545                }
 546        }
 547
 548        free(buf);
 549        return error_code ? NULL : path;
 550}
 551
 552static const char *setup_explicit_git_dir(const char *gitdirenv,
 553                                          struct strbuf *cwd,
 554                                          int *nongit_ok)
 555{
 556        const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 557        const char *worktree;
 558        char *gitfile;
 559        int offset;
 560
 561        if (PATH_MAX - 40 < strlen(gitdirenv))
 562                die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 563
 564        gitfile = (char*)read_gitfile(gitdirenv);
 565        if (gitfile) {
 566                gitfile = xstrdup(gitfile);
 567                gitdirenv = gitfile;
 568        }
 569
 570        if (!is_git_directory(gitdirenv)) {
 571                if (nongit_ok) {
 572                        *nongit_ok = 1;
 573                        free(gitfile);
 574                        return NULL;
 575                }
 576                die("Not a git repository: '%s'", gitdirenv);
 577        }
 578
 579        if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 580                free(gitfile);
 581                return NULL;
 582        }
 583
 584        /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 585        if (work_tree_env)
 586                set_git_work_tree(work_tree_env);
 587        else if (is_bare_repository_cfg > 0) {
 588                if (git_work_tree_cfg) {
 589                        /* #22.2, #30 */
 590                        warning("core.bare and core.worktree do not make sense");
 591                        work_tree_config_is_bogus = 1;
 592                }
 593
 594                /* #18, #26 */
 595                set_git_dir(gitdirenv);
 596                free(gitfile);
 597                return NULL;
 598        }
 599        else if (git_work_tree_cfg) { /* #6, #14 */
 600                if (is_absolute_path(git_work_tree_cfg))
 601                        set_git_work_tree(git_work_tree_cfg);
 602                else {
 603                        char *core_worktree;
 604                        if (chdir(gitdirenv))
 605                                die_errno("Could not chdir to '%s'", gitdirenv);
 606                        if (chdir(git_work_tree_cfg))
 607                                die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 608                        core_worktree = xgetcwd();
 609                        if (chdir(cwd->buf))
 610                                die_errno("Could not come back to cwd");
 611                        set_git_work_tree(core_worktree);
 612                        free(core_worktree);
 613                }
 614        }
 615        else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 616                /* #16d */
 617                set_git_dir(gitdirenv);
 618                free(gitfile);
 619                return NULL;
 620        }
 621        else /* #2, #10 */
 622                set_git_work_tree(".");
 623
 624        /* set_git_work_tree() must have been called by now */
 625        worktree = get_git_work_tree();
 626
 627        /* both get_git_work_tree() and cwd are already normalized */
 628        if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */
 629                set_git_dir(gitdirenv);
 630                free(gitfile);
 631                return NULL;
 632        }
 633
 634        offset = dir_inside_of(cwd->buf, worktree);
 635        if (offset >= 0) {      /* cwd inside worktree? */
 636                set_git_dir(real_path(gitdirenv));
 637                if (chdir(worktree))
 638                        die_errno("Could not chdir to '%s'", worktree);
 639                strbuf_addch(cwd, '/');
 640                free(gitfile);
 641                return cwd->buf + offset;
 642        }
 643
 644        /* cwd outside worktree */
 645        set_git_dir(gitdirenv);
 646        free(gitfile);
 647        return NULL;
 648}
 649
 650static const char *setup_discovered_git_dir(const char *gitdir,
 651                                            struct strbuf *cwd, int offset,
 652                                            int *nongit_ok)
 653{
 654        if (check_repository_format_gently(gitdir, nongit_ok))
 655                return NULL;
 656
 657        /* --work-tree is set without --git-dir; use discovered one */
 658        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 659                if (offset != cwd->len && !is_absolute_path(gitdir))
 660                        gitdir = xstrdup(real_path(gitdir));
 661                if (chdir(cwd->buf))
 662                        die_errno("Could not come back to cwd");
 663                return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 664        }
 665
 666        /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 667        if (is_bare_repository_cfg > 0) {
 668                set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));
 669                if (chdir(cwd->buf))
 670                        die_errno("Could not come back to cwd");
 671                return NULL;
 672        }
 673
 674        /* #0, #1, #5, #8, #9, #12, #13 */
 675        set_git_work_tree(".");
 676        if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 677                set_git_dir(gitdir);
 678        inside_git_dir = 0;
 679        inside_work_tree = 1;
 680        if (offset == cwd->len)
 681                return NULL;
 682
 683        /* Make "offset" point to past the '/', and add a '/' at the end */
 684        offset++;
 685        strbuf_addch(cwd, '/');
 686        return cwd->buf + offset;
 687}
 688
 689/* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 690static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
 691                                      int *nongit_ok)
 692{
 693        int root_len;
 694
 695        if (check_repository_format_gently(".", nongit_ok))
 696                return NULL;
 697
 698        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 699
 700        /* --work-tree is set without --git-dir; use discovered one */
 701        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 702                const char *gitdir;
 703
 704                gitdir = offset == cwd->len ? "." : xmemdupz(cwd->buf, offset);
 705                if (chdir(cwd->buf))
 706                        die_errno("Could not come back to cwd");
 707                return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 708        }
 709
 710        inside_git_dir = 1;
 711        inside_work_tree = 0;
 712        if (offset != cwd->len) {
 713                if (chdir(cwd->buf))
 714                        die_errno("Cannot come back to cwd");
 715                root_len = offset_1st_component(cwd->buf);
 716                strbuf_setlen(cwd, offset > root_len ? offset : root_len);
 717                set_git_dir(cwd->buf);
 718        }
 719        else
 720                set_git_dir(".");
 721        return NULL;
 722}
 723
 724static const char *setup_nongit(const char *cwd, int *nongit_ok)
 725{
 726        if (!nongit_ok)
 727                die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
 728        if (chdir(cwd))
 729                die_errno("Cannot come back to cwd");
 730        *nongit_ok = 1;
 731        return NULL;
 732}
 733
 734static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 735{
 736        struct stat buf;
 737        if (stat(path, &buf)) {
 738                die_errno("failed to stat '%*s%s%s'",
 739                                prefix_len,
 740                                prefix ? prefix : "",
 741                                prefix ? "/" : "", path);
 742        }
 743        return buf.st_dev;
 744}
 745
 746/*
 747 * A "string_list_each_func_t" function that canonicalizes an entry
 748 * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 749 * discards it if unusable.  The presence of an empty entry in
 750 * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 751 * subsequent entries.
 752 */
 753static int canonicalize_ceiling_entry(struct string_list_item *item,
 754                                      void *cb_data)
 755{
 756        int *empty_entry_found = cb_data;
 757        char *ceil = item->string;
 758
 759        if (!*ceil) {
 760                *empty_entry_found = 1;
 761                return 0;
 762        } else if (!is_absolute_path(ceil)) {
 763                return 0;
 764        } else if (*empty_entry_found) {
 765                /* Keep entry but do not canonicalize it */
 766                return 1;
 767        } else {
 768                const char *real_path = real_path_if_valid(ceil);
 769                if (!real_path)
 770                        return 0;
 771                free(item->string);
 772                item->string = xstrdup(real_path);
 773                return 1;
 774        }
 775}
 776
 777/*
 778 * We cannot decide in this function whether we are in the work tree or
 779 * not, since the config can only be read _after_ this function was called.
 780 */
 781static const char *setup_git_directory_gently_1(int *nongit_ok)
 782{
 783        const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 784        struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 785        static struct strbuf cwd = STRBUF_INIT;
 786        const char *gitdirenv, *ret;
 787        char *gitfile;
 788        int offset, offset_parent, ceil_offset = -1;
 789        dev_t current_device = 0;
 790        int one_filesystem = 1;
 791
 792        /*
 793         * We may have read an incomplete configuration before
 794         * setting-up the git directory. If so, clear the cache so
 795         * that the next queries to the configuration reload complete
 796         * configuration (including the per-repo config file that we
 797         * ignored previously).
 798         */
 799        git_config_clear();
 800
 801        /*
 802         * Let's assume that we are in a git repository.
 803         * If it turns out later that we are somewhere else, the value will be
 804         * updated accordingly.
 805         */
 806        if (nongit_ok)
 807                *nongit_ok = 0;
 808
 809        if (strbuf_getcwd(&cwd))
 810                die_errno("Unable to read current working directory");
 811        offset = cwd.len;
 812
 813        /*
 814         * If GIT_DIR is set explicitly, we're not going
 815         * to do any discovery, but we still do repository
 816         * validation.
 817         */
 818        gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 819        if (gitdirenv)
 820                return setup_explicit_git_dir(gitdirenv, &cwd, nongit_ok);
 821
 822        if (env_ceiling_dirs) {
 823                int empty_entry_found = 0;
 824
 825                string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 826                filter_string_list(&ceiling_dirs, 0,
 827                                   canonicalize_ceiling_entry, &empty_entry_found);
 828                ceil_offset = longest_ancestor_length(cwd.buf, &ceiling_dirs);
 829                string_list_clear(&ceiling_dirs, 0);
 830        }
 831
 832        if (ceil_offset < 0 && has_dos_drive_prefix(cwd.buf))
 833                ceil_offset = 1;
 834
 835        /*
 836         * Test in the following order (relative to the cwd):
 837         * - .git (file containing "gitdir: <path>")
 838         * - .git/
 839         * - ./ (bare)
 840         * - ../.git
 841         * - ../.git/
 842         * - ../ (bare)
 843         * - ../../.git/
 844         *   etc.
 845         */
 846        one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 847        if (one_filesystem)
 848                current_device = get_device_or_die(".", NULL, 0);
 849        for (;;) {
 850                gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
 851                if (gitfile)
 852                        gitdirenv = gitfile = xstrdup(gitfile);
 853                else {
 854                        if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
 855                                gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 856                }
 857
 858                if (gitdirenv) {
 859                        ret = setup_discovered_git_dir(gitdirenv,
 860                                                       &cwd, offset,
 861                                                       nongit_ok);
 862                        free(gitfile);
 863                        return ret;
 864                }
 865                free(gitfile);
 866
 867                if (is_git_directory("."))
 868                        return setup_bare_git_dir(&cwd, offset, nongit_ok);
 869
 870                offset_parent = offset;
 871                while (--offset_parent > ceil_offset && cwd.buf[offset_parent] != '/');
 872                if (offset_parent <= ceil_offset)
 873                        return setup_nongit(cwd.buf, nongit_ok);
 874                if (one_filesystem) {
 875                        dev_t parent_device = get_device_or_die("..", cwd.buf,
 876                                                                offset);
 877                        if (parent_device != current_device) {
 878                                if (nongit_ok) {
 879                                        if (chdir(cwd.buf))
 880                                                die_errno("Cannot come back to cwd");
 881                                        *nongit_ok = 1;
 882                                        return NULL;
 883                                }
 884                                strbuf_setlen(&cwd, offset);
 885                                die("Not a git repository (or any parent up to mount point %s)\n"
 886                                "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).",
 887                                    cwd.buf);
 888                        }
 889                }
 890                if (chdir("..")) {
 891                        strbuf_setlen(&cwd, offset);
 892                        die_errno("Cannot change to '%s/..'", cwd.buf);
 893                }
 894                offset = offset_parent;
 895        }
 896}
 897
 898const char *setup_git_directory_gently(int *nongit_ok)
 899{
 900        const char *prefix;
 901
 902        prefix = setup_git_directory_gently_1(nongit_ok);
 903        if (prefix)
 904                setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 905        else
 906                setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
 907
 908        if (startup_info) {
 909                startup_info->have_repository = !nongit_ok || !*nongit_ok;
 910                startup_info->prefix = prefix;
 911        }
 912        return prefix;
 913}
 914
 915int git_config_perm(const char *var, const char *value)
 916{
 917        int i;
 918        char *endptr;
 919
 920        if (value == NULL)
 921                return PERM_GROUP;
 922
 923        if (!strcmp(value, "umask"))
 924                return PERM_UMASK;
 925        if (!strcmp(value, "group"))
 926                return PERM_GROUP;
 927        if (!strcmp(value, "all") ||
 928            !strcmp(value, "world") ||
 929            !strcmp(value, "everybody"))
 930                return PERM_EVERYBODY;
 931
 932        /* Parse octal numbers */
 933        i = strtol(value, &endptr, 8);
 934
 935        /* If not an octal number, maybe true/false? */
 936        if (*endptr != 0)
 937                return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
 938
 939        /*
 940         * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
 941         * a chmod value to restrict to.
 942         */
 943        switch (i) {
 944        case PERM_UMASK:               /* 0 */
 945                return PERM_UMASK;
 946        case OLD_PERM_GROUP:           /* 1 */
 947                return PERM_GROUP;
 948        case OLD_PERM_EVERYBODY:       /* 2 */
 949                return PERM_EVERYBODY;
 950        }
 951
 952        /* A filemode value was given: 0xxx */
 953
 954        if ((i & 0600) != 0600)
 955                die("Problem with core.sharedRepository filemode value "
 956                    "(0%.3o).\nThe owner of files must always have "
 957                    "read and write permissions.", i);
 958
 959        /*
 960         * Mask filemode value. Others can not get write permission.
 961         * x flags for directories are handled separately.
 962         */
 963        return -(i & 0666);
 964}
 965
 966int check_repository_format_version(const char *var, const char *value, void *cb)
 967{
 968        int ret = check_repo_format(var, value, cb);
 969        if (ret)
 970                return ret;
 971        if (strcmp(var, "core.bare") == 0) {
 972                is_bare_repository_cfg = git_config_bool(var, value);
 973                if (is_bare_repository_cfg == 1)
 974                        inside_work_tree = -1;
 975        } else if (strcmp(var, "core.worktree") == 0) {
 976                if (!value)
 977                        return config_error_nonbool(var);
 978                free(git_work_tree_cfg);
 979                git_work_tree_cfg = xstrdup(value);
 980                inside_work_tree = -1;
 981        }
 982        return 0;
 983}
 984
 985int check_repository_format(void)
 986{
 987        return check_repository_format_gently(get_git_dir(), NULL);
 988}
 989
 990/*
 991 * Returns the "prefix", a path to the current working directory
 992 * relative to the work tree root, or NULL, if the current working
 993 * directory is not a strict subdirectory of the work tree root. The
 994 * prefix always ends with a '/' character.
 995 */
 996const char *setup_git_directory(void)
 997{
 998        return setup_git_directory_gently(NULL);
 999}
1000
1001const char *resolve_gitdir(const char *suspect)
1002{
1003        if (is_git_directory(suspect))
1004                return suspect;
1005        return read_gitfile(suspect);
1006}
1007
1008/* if any standard file descriptor is missing open it to /dev/null */
1009void sanitize_stdfds(void)
1010{
1011        int fd = open("/dev/null", O_RDWR, 0);
1012        while (fd != -1 && fd < 2)
1013                fd = dup(fd);
1014        if (fd == -1)
1015                die_errno("open /dev/null or dup failed");
1016        if (fd > 2)
1017                close(fd);
1018}
1019
1020int daemonize(void)
1021{
1022#ifdef NO_POSIX_GOODIES
1023        errno = ENOSYS;
1024        return -1;
1025#else
1026        switch (fork()) {
1027                case 0:
1028                        break;
1029                case -1:
1030                        die_errno("fork failed");
1031                default:
1032                        exit(0);
1033        }
1034        if (setsid() == -1)
1035                die_errno("setsid failed");
1036        close(0);
1037        close(1);
1038        close(2);
1039        sanitize_stdfds();
1040        return 0;
1041#endif
1042}