setup.con commit Sync with Git 2.14.4 (9e0f06d)
   1#include "cache.h"
   2#include "repository.h"
   3#include "config.h"
   4#include "dir.h"
   5#include "string-list.h"
   6
   7static int inside_git_dir = -1;
   8static int inside_work_tree = -1;
   9static int work_tree_config_is_bogus;
  10
  11static struct startup_info the_startup_info;
  12struct startup_info *startup_info = &the_startup_info;
  13
  14/*
  15 * The input parameter must contain an absolute path, and it must already be
  16 * normalized.
  17 *
  18 * Find the part of an absolute path that lies inside the work tree by
  19 * dereferencing symlinks outside the work tree, for example:
  20 * /dir1/repo/dir2/file   (work tree is /dir1/repo)      -> dir2/file
  21 * /dir/file              (work tree is /)               -> dir/file
  22 * /dir/symlink1/symlink2 (symlink1 points to work tree) -> symlink2
  23 * /dir/repolink/file     (repolink points to /dir/repo) -> file
  24 * /dir/repo              (exactly equal to work tree)   -> (empty string)
  25 */
  26static int abspath_part_inside_repo(char *path)
  27{
  28        size_t len;
  29        size_t wtlen;
  30        char *path0;
  31        int off;
  32        const char *work_tree = get_git_work_tree();
  33
  34        if (!work_tree)
  35                return -1;
  36        wtlen = strlen(work_tree);
  37        len = strlen(path);
  38        off = offset_1st_component(path);
  39
  40        /* check if work tree is already the prefix */
  41        if (wtlen <= len && !strncmp(path, work_tree, wtlen)) {
  42                if (path[wtlen] == '/') {
  43                        memmove(path, path + wtlen + 1, len - wtlen);
  44                        return 0;
  45                } else if (path[wtlen - 1] == '/' || path[wtlen] == '\0') {
  46                        /* work tree is the root, or the whole path */
  47                        memmove(path, path + wtlen, len - wtlen + 1);
  48                        return 0;
  49                }
  50                /* work tree might match beginning of a symlink to work tree */
  51                off = wtlen;
  52        }
  53        path0 = path;
  54        path += off;
  55
  56        /* check each '/'-terminated level */
  57        while (*path) {
  58                path++;
  59                if (*path == '/') {
  60                        *path = '\0';
  61                        if (strcmp(real_path(path0), work_tree) == 0) {
  62                                memmove(path0, path + 1, len - (path - path0));
  63                                return 0;
  64                        }
  65                        *path = '/';
  66                }
  67        }
  68
  69        /* check whole path */
  70        if (strcmp(real_path(path0), work_tree) == 0) {
  71                *path0 = '\0';
  72                return 0;
  73        }
  74
  75        return -1;
  76}
  77
  78/*
  79 * Normalize "path", prepending the "prefix" for relative paths. If
  80 * remaining_prefix is not NULL, return the actual prefix still
  81 * remains in the path. For example, prefix = sub1/sub2/ and path is
  82 *
  83 *  foo          -> sub1/sub2/foo  (full prefix)
  84 *  ../foo       -> sub1/foo       (remaining prefix is sub1/)
  85 *  ../../bar    -> bar            (no remaining prefix)
  86 *  ../../sub1/sub2/foo -> sub1/sub2/foo (but no remaining prefix)
  87 *  `pwd`/../bar -> sub1/bar       (no remaining prefix)
  88 */
  89char *prefix_path_gently(const char *prefix, int len,
  90                         int *remaining_prefix, const char *path)
  91{
  92        const char *orig = path;
  93        char *sanitized;
  94        if (is_absolute_path(orig)) {
  95                sanitized = xmallocz(strlen(path));
  96                if (remaining_prefix)
  97                        *remaining_prefix = 0;
  98                if (normalize_path_copy_len(sanitized, path, remaining_prefix)) {
  99                        free(sanitized);
 100                        return NULL;
 101                }
 102                if (abspath_part_inside_repo(sanitized)) {
 103                        free(sanitized);
 104                        return NULL;
 105                }
 106        } else {
 107                sanitized = xstrfmt("%.*s%s", len, len ? prefix : "", path);
 108                if (remaining_prefix)
 109                        *remaining_prefix = len;
 110                if (normalize_path_copy_len(sanitized, sanitized, remaining_prefix)) {
 111                        free(sanitized);
 112                        return NULL;
 113                }
 114        }
 115        return sanitized;
 116}
 117
 118char *prefix_path(const char *prefix, int len, const char *path)
 119{
 120        char *r = prefix_path_gently(prefix, len, NULL, path);
 121        if (!r)
 122                die("'%s' is outside repository", path);
 123        return r;
 124}
 125
 126int path_inside_repo(const char *prefix, const char *path)
 127{
 128        int len = prefix ? strlen(prefix) : 0;
 129        char *r = prefix_path_gently(prefix, len, NULL, path);
 130        if (r) {
 131                free(r);
 132                return 1;
 133        }
 134        return 0;
 135}
 136
 137int check_filename(const char *prefix, const char *arg)
 138{
 139        char *to_free = NULL;
 140        struct stat st;
 141
 142        if (skip_prefix(arg, ":/", &arg)) {
 143                if (!*arg) /* ":/" is root dir, always exists */
 144                        return 1;
 145                prefix = NULL;
 146        } else if (skip_prefix(arg, ":!", &arg) ||
 147                   skip_prefix(arg, ":^", &arg)) {
 148                if (!*arg) /* excluding everything is silly, but allowed */
 149                        return 1;
 150        }
 151
 152        if (prefix)
 153                arg = to_free = prefix_filename(prefix, arg);
 154
 155        if (!lstat(arg, &st)) {
 156                free(to_free);
 157                return 1; /* file exists */
 158        }
 159        if (is_missing_file_error(errno)) {
 160                free(to_free);
 161                return 0; /* file does not exist */
 162        }
 163        die_errno("failed to stat '%s'", arg);
 164}
 165
 166static void NORETURN die_verify_filename(const char *prefix,
 167                                         const char *arg,
 168                                         int diagnose_misspelt_rev)
 169{
 170        if (!diagnose_misspelt_rev)
 171                die(_("%s: no such path in the working tree.\n"
 172                      "Use 'git <command> -- <path>...' to specify paths that do not exist locally."),
 173                    arg);
 174        /*
 175         * Saying "'(icase)foo' does not exist in the index" when the
 176         * user gave us ":(icase)foo" is just stupid.  A magic pathspec
 177         * begins with a colon and is followed by a non-alnum; do not
 178         * let maybe_die_on_misspelt_object_name() even trigger.
 179         */
 180        if (!(arg[0] == ':' && !isalnum(arg[1])))
 181                maybe_die_on_misspelt_object_name(arg, prefix);
 182
 183        /* ... or fall back the most general message. */
 184        die(_("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
 185              "Use '--' to separate paths from revisions, like this:\n"
 186              "'git <command> [<revision>...] -- [<file>...]'"), arg);
 187
 188}
 189
 190/*
 191 * Check for arguments that don't resolve as actual files,
 192 * but which look sufficiently like pathspecs that we'll consider
 193 * them such for the purposes of rev/pathspec DWIM parsing.
 194 */
 195static int looks_like_pathspec(const char *arg)
 196{
 197        /* anything with a wildcard character */
 198        if (!no_wildcard(arg))
 199                return 1;
 200
 201        /* long-form pathspec magic */
 202        if (starts_with(arg, ":("))
 203                return 1;
 204
 205        return 0;
 206}
 207
 208/*
 209 * Verify a filename that we got as an argument for a pathspec
 210 * entry. Note that a filename that begins with "-" never verifies
 211 * as true, because even if such a filename were to exist, we want
 212 * it to be preceded by the "--" marker (or we want the user to
 213 * use a format like "./-filename")
 214 *
 215 * The "diagnose_misspelt_rev" is used to provide a user-friendly
 216 * diagnosis when dying upon finding that "name" is not a pathname.
 217 * If set to 1, the diagnosis will try to diagnose "name" as an
 218 * invalid object name (e.g. HEAD:foo). If set to 0, the diagnosis
 219 * will only complain about an inexisting file.
 220 *
 221 * This function is typically called to check that a "file or rev"
 222 * argument is unambiguous. In this case, the caller will want
 223 * diagnose_misspelt_rev == 1 when verifying the first non-rev
 224 * argument (which could have been a revision), and
 225 * diagnose_misspelt_rev == 0 for the next ones (because we already
 226 * saw a filename, there's not ambiguity anymore).
 227 */
 228void verify_filename(const char *prefix,
 229                     const char *arg,
 230                     int diagnose_misspelt_rev)
 231{
 232        if (*arg == '-')
 233                die("option '%s' must come before non-option arguments", arg);
 234        if (looks_like_pathspec(arg) || check_filename(prefix, arg))
 235                return;
 236        die_verify_filename(prefix, arg, diagnose_misspelt_rev);
 237}
 238
 239/*
 240 * Opposite of the above: the command line did not have -- marker
 241 * and we parsed the arg as a refname.  It should not be interpretable
 242 * as a filename.
 243 */
 244void verify_non_filename(const char *prefix, const char *arg)
 245{
 246        if (!is_inside_work_tree() || is_inside_git_dir())
 247                return;
 248        if (*arg == '-')
 249                return; /* flag */
 250        if (!check_filename(prefix, arg))
 251                return;
 252        die(_("ambiguous argument '%s': both revision and filename\n"
 253              "Use '--' to separate paths from revisions, like this:\n"
 254              "'git <command> [<revision>...] -- [<file>...]'"), arg);
 255}
 256
 257int get_common_dir(struct strbuf *sb, const char *gitdir)
 258{
 259        const char *git_env_common_dir = getenv(GIT_COMMON_DIR_ENVIRONMENT);
 260        if (git_env_common_dir) {
 261                strbuf_addstr(sb, git_env_common_dir);
 262                return 1;
 263        } else {
 264                return get_common_dir_noenv(sb, gitdir);
 265        }
 266}
 267
 268int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
 269{
 270        struct strbuf data = STRBUF_INIT;
 271        struct strbuf path = STRBUF_INIT;
 272        int ret = 0;
 273
 274        strbuf_addf(&path, "%s/commondir", gitdir);
 275        if (file_exists(path.buf)) {
 276                if (strbuf_read_file(&data, path.buf, 0) <= 0)
 277                        die_errno(_("failed to read %s"), path.buf);
 278                while (data.len && (data.buf[data.len - 1] == '\n' ||
 279                                    data.buf[data.len - 1] == '\r'))
 280                        data.len--;
 281                data.buf[data.len] = '\0';
 282                strbuf_reset(&path);
 283                if (!is_absolute_path(data.buf))
 284                        strbuf_addf(&path, "%s/", gitdir);
 285                strbuf_addbuf(&path, &data);
 286                strbuf_add_real_path(sb, path.buf);
 287                ret = 1;
 288        } else {
 289                strbuf_addstr(sb, gitdir);
 290        }
 291
 292        strbuf_release(&data);
 293        strbuf_release(&path);
 294        return ret;
 295}
 296
 297/*
 298 * Test if it looks like we're at a git directory.
 299 * We want to see:
 300 *
 301 *  - either an objects/ directory _or_ the proper
 302 *    GIT_OBJECT_DIRECTORY environment variable
 303 *  - a refs/ directory
 304 *  - either a HEAD symlink or a HEAD file that is formatted as
 305 *    a proper "ref:", or a regular file HEAD that has a properly
 306 *    formatted sha1 object name.
 307 */
 308int is_git_directory(const char *suspect)
 309{
 310        struct strbuf path = STRBUF_INIT;
 311        int ret = 0;
 312        size_t len;
 313
 314        /* Check worktree-related signatures */
 315        strbuf_addstr(&path, suspect);
 316        strbuf_complete(&path, '/');
 317        strbuf_addstr(&path, "HEAD");
 318        if (validate_headref(path.buf))
 319                goto done;
 320
 321        strbuf_reset(&path);
 322        get_common_dir(&path, suspect);
 323        len = path.len;
 324
 325        /* Check non-worktree-related signatures */
 326        if (getenv(DB_ENVIRONMENT)) {
 327                if (access(getenv(DB_ENVIRONMENT), X_OK))
 328                        goto done;
 329        }
 330        else {
 331                strbuf_setlen(&path, len);
 332                strbuf_addstr(&path, "/objects");
 333                if (access(path.buf, X_OK))
 334                        goto done;
 335        }
 336
 337        strbuf_setlen(&path, len);
 338        strbuf_addstr(&path, "/refs");
 339        if (access(path.buf, X_OK))
 340                goto done;
 341
 342        ret = 1;
 343done:
 344        strbuf_release(&path);
 345        return ret;
 346}
 347
 348int is_nonbare_repository_dir(struct strbuf *path)
 349{
 350        int ret = 0;
 351        int gitfile_error;
 352        size_t orig_path_len = path->len;
 353        assert(orig_path_len != 0);
 354        strbuf_complete(path, '/');
 355        strbuf_addstr(path, ".git");
 356        if (read_gitfile_gently(path->buf, &gitfile_error) || is_git_directory(path->buf))
 357                ret = 1;
 358        if (gitfile_error == READ_GITFILE_ERR_OPEN_FAILED ||
 359            gitfile_error == READ_GITFILE_ERR_READ_FAILED)
 360                ret = 1;
 361        strbuf_setlen(path, orig_path_len);
 362        return ret;
 363}
 364
 365int is_inside_git_dir(void)
 366{
 367        if (inside_git_dir < 0)
 368                inside_git_dir = is_inside_dir(get_git_dir());
 369        return inside_git_dir;
 370}
 371
 372int is_inside_work_tree(void)
 373{
 374        if (inside_work_tree < 0)
 375                inside_work_tree = is_inside_dir(get_git_work_tree());
 376        return inside_work_tree;
 377}
 378
 379void setup_work_tree(void)
 380{
 381        const char *work_tree, *git_dir;
 382        static int initialized = 0;
 383
 384        if (initialized)
 385                return;
 386
 387        if (work_tree_config_is_bogus)
 388                die("unable to set up work tree using invalid config");
 389
 390        work_tree = get_git_work_tree();
 391        git_dir = get_git_dir();
 392        if (!is_absolute_path(git_dir))
 393                git_dir = real_path(get_git_dir());
 394        if (!work_tree || chdir(work_tree))
 395                die("This operation must be run in a work tree");
 396
 397        /*
 398         * Make sure subsequent git processes find correct worktree
 399         * if $GIT_WORK_TREE is set relative
 400         */
 401        if (getenv(GIT_WORK_TREE_ENVIRONMENT))
 402                setenv(GIT_WORK_TREE_ENVIRONMENT, ".", 1);
 403
 404        set_git_dir(remove_leading_path(git_dir, work_tree));
 405        initialized = 1;
 406}
 407
 408static int check_repo_format(const char *var, const char *value, void *vdata)
 409{
 410        struct repository_format *data = vdata;
 411        const char *ext;
 412
 413        if (strcmp(var, "core.repositoryformatversion") == 0)
 414                data->version = git_config_int(var, value);
 415        else if (skip_prefix(var, "extensions.", &ext)) {
 416                /*
 417                 * record any known extensions here; otherwise,
 418                 * we fall through to recording it as unknown, and
 419                 * check_repository_format will complain
 420                 */
 421                if (!strcmp(ext, "noop"))
 422                        ;
 423                else if (!strcmp(ext, "preciousobjects"))
 424                        data->precious_objects = git_config_bool(var, value);
 425                else
 426                        string_list_append(&data->unknown_extensions, ext);
 427        } else if (strcmp(var, "core.bare") == 0) {
 428                data->is_bare = git_config_bool(var, value);
 429        } else if (strcmp(var, "core.worktree") == 0) {
 430                if (!value)
 431                        return config_error_nonbool(var);
 432                data->work_tree = xstrdup(value);
 433        }
 434        return 0;
 435}
 436
 437static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
 438{
 439        struct strbuf sb = STRBUF_INIT;
 440        struct strbuf err = STRBUF_INIT;
 441        struct repository_format candidate;
 442        int has_common;
 443
 444        has_common = get_common_dir(&sb, gitdir);
 445        strbuf_addstr(&sb, "/config");
 446        read_repository_format(&candidate, sb.buf);
 447        strbuf_release(&sb);
 448
 449        /*
 450         * For historical use of check_repository_format() in git-init,
 451         * we treat a missing config as a silent "ok", even when nongit_ok
 452         * is unset.
 453         */
 454        if (candidate.version < 0)
 455                return 0;
 456
 457        if (verify_repository_format(&candidate, &err) < 0) {
 458                if (nongit_ok) {
 459                        warning("%s", err.buf);
 460                        strbuf_release(&err);
 461                        *nongit_ok = -1;
 462                        return -1;
 463                }
 464                die("%s", err.buf);
 465        }
 466
 467        repository_format_precious_objects = candidate.precious_objects;
 468        string_list_clear(&candidate.unknown_extensions, 0);
 469        if (!has_common) {
 470                if (candidate.is_bare != -1) {
 471                        is_bare_repository_cfg = candidate.is_bare;
 472                        if (is_bare_repository_cfg == 1)
 473                                inside_work_tree = -1;
 474                }
 475                if (candidate.work_tree) {
 476                        free(git_work_tree_cfg);
 477                        git_work_tree_cfg = candidate.work_tree;
 478                        inside_work_tree = -1;
 479                }
 480        } else {
 481                free(candidate.work_tree);
 482        }
 483
 484        return 0;
 485}
 486
 487int read_repository_format(struct repository_format *format, const char *path)
 488{
 489        memset(format, 0, sizeof(*format));
 490        format->version = -1;
 491        format->is_bare = -1;
 492        string_list_init(&format->unknown_extensions, 1);
 493        git_config_from_file(check_repo_format, path, format);
 494        return format->version;
 495}
 496
 497int verify_repository_format(const struct repository_format *format,
 498                             struct strbuf *err)
 499{
 500        if (GIT_REPO_VERSION_READ < format->version) {
 501                strbuf_addf(err, _("Expected git repo version <= %d, found %d"),
 502                            GIT_REPO_VERSION_READ, format->version);
 503                return -1;
 504        }
 505
 506        if (format->version >= 1 && format->unknown_extensions.nr) {
 507                int i;
 508
 509                strbuf_addstr(err, _("unknown repository extensions found:"));
 510
 511                for (i = 0; i < format->unknown_extensions.nr; i++)
 512                        strbuf_addf(err, "\n\t%s",
 513                                    format->unknown_extensions.items[i].string);
 514                return -1;
 515        }
 516
 517        return 0;
 518}
 519
 520void read_gitfile_error_die(int error_code, const char *path, const char *dir)
 521{
 522        switch (error_code) {
 523        case READ_GITFILE_ERR_STAT_FAILED:
 524        case READ_GITFILE_ERR_NOT_A_FILE:
 525                /* non-fatal; follow return path */
 526                break;
 527        case READ_GITFILE_ERR_OPEN_FAILED:
 528                die_errno("Error opening '%s'", path);
 529        case READ_GITFILE_ERR_TOO_LARGE:
 530                die("Too large to be a .git file: '%s'", path);
 531        case READ_GITFILE_ERR_READ_FAILED:
 532                die("Error reading %s", path);
 533        case READ_GITFILE_ERR_INVALID_FORMAT:
 534                die("Invalid gitfile format: %s", path);
 535        case READ_GITFILE_ERR_NO_PATH:
 536                die("No path in gitfile: %s", path);
 537        case READ_GITFILE_ERR_NOT_A_REPO:
 538                die("Not a git repository: %s", dir);
 539        default:
 540                die("BUG: unknown error code");
 541        }
 542}
 543
 544/*
 545 * Try to read the location of the git directory from the .git file,
 546 * return path to git directory if found. The return value comes from
 547 * a shared buffer.
 548 *
 549 * On failure, if return_error_code is not NULL, return_error_code
 550 * will be set to an error code and NULL will be returned. If
 551 * return_error_code is NULL the function will die instead (for most
 552 * cases).
 553 */
 554const char *read_gitfile_gently(const char *path, int *return_error_code)
 555{
 556        const int max_file_size = 1 << 20;  /* 1MB */
 557        int error_code = 0;
 558        char *buf = NULL;
 559        char *dir = NULL;
 560        const char *slash;
 561        struct stat st;
 562        int fd;
 563        ssize_t len;
 564
 565        if (stat(path, &st)) {
 566                /* NEEDSWORK: discern between ENOENT vs other errors */
 567                error_code = READ_GITFILE_ERR_STAT_FAILED;
 568                goto cleanup_return;
 569        }
 570        if (!S_ISREG(st.st_mode)) {
 571                error_code = READ_GITFILE_ERR_NOT_A_FILE;
 572                goto cleanup_return;
 573        }
 574        if (st.st_size > max_file_size) {
 575                error_code = READ_GITFILE_ERR_TOO_LARGE;
 576                goto cleanup_return;
 577        }
 578        fd = open(path, O_RDONLY);
 579        if (fd < 0) {
 580                error_code = READ_GITFILE_ERR_OPEN_FAILED;
 581                goto cleanup_return;
 582        }
 583        buf = xmallocz(st.st_size);
 584        len = read_in_full(fd, buf, st.st_size);
 585        close(fd);
 586        if (len != st.st_size) {
 587                error_code = READ_GITFILE_ERR_READ_FAILED;
 588                goto cleanup_return;
 589        }
 590        if (!starts_with(buf, "gitdir: ")) {
 591                error_code = READ_GITFILE_ERR_INVALID_FORMAT;
 592                goto cleanup_return;
 593        }
 594        while (buf[len - 1] == '\n' || buf[len - 1] == '\r')
 595                len--;
 596        if (len < 9) {
 597                error_code = READ_GITFILE_ERR_NO_PATH;
 598                goto cleanup_return;
 599        }
 600        buf[len] = '\0';
 601        dir = buf + 8;
 602
 603        if (!is_absolute_path(dir) && (slash = strrchr(path, '/'))) {
 604                size_t pathlen = slash+1 - path;
 605                dir = xstrfmt("%.*s%.*s", (int)pathlen, path,
 606                              (int)(len - 8), buf + 8);
 607                free(buf);
 608                buf = dir;
 609        }
 610        if (!is_git_directory(dir)) {
 611                error_code = READ_GITFILE_ERR_NOT_A_REPO;
 612                goto cleanup_return;
 613        }
 614        path = real_path(dir);
 615
 616cleanup_return:
 617        if (return_error_code)
 618                *return_error_code = error_code;
 619        else if (error_code)
 620                read_gitfile_error_die(error_code, path, dir);
 621
 622        free(buf);
 623        return error_code ? NULL : path;
 624}
 625
 626static const char *setup_explicit_git_dir(const char *gitdirenv,
 627                                          struct strbuf *cwd,
 628                                          int *nongit_ok)
 629{
 630        const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
 631        const char *worktree;
 632        char *gitfile;
 633        int offset;
 634
 635        if (PATH_MAX - 40 < strlen(gitdirenv))
 636                die("'$%s' too big", GIT_DIR_ENVIRONMENT);
 637
 638        gitfile = (char*)read_gitfile(gitdirenv);
 639        if (gitfile) {
 640                gitfile = xstrdup(gitfile);
 641                gitdirenv = gitfile;
 642        }
 643
 644        if (!is_git_directory(gitdirenv)) {
 645                if (nongit_ok) {
 646                        *nongit_ok = 1;
 647                        free(gitfile);
 648                        return NULL;
 649                }
 650                die("Not a git repository: '%s'", gitdirenv);
 651        }
 652
 653        if (check_repository_format_gently(gitdirenv, nongit_ok)) {
 654                free(gitfile);
 655                return NULL;
 656        }
 657
 658        /* #3, #7, #11, #15, #19, #23, #27, #31 (see t1510) */
 659        if (work_tree_env)
 660                set_git_work_tree(work_tree_env);
 661        else if (is_bare_repository_cfg > 0) {
 662                if (git_work_tree_cfg) {
 663                        /* #22.2, #30 */
 664                        warning("core.bare and core.worktree do not make sense");
 665                        work_tree_config_is_bogus = 1;
 666                }
 667
 668                /* #18, #26 */
 669                set_git_dir(gitdirenv);
 670                free(gitfile);
 671                return NULL;
 672        }
 673        else if (git_work_tree_cfg) { /* #6, #14 */
 674                if (is_absolute_path(git_work_tree_cfg))
 675                        set_git_work_tree(git_work_tree_cfg);
 676                else {
 677                        char *core_worktree;
 678                        if (chdir(gitdirenv))
 679                                die_errno("Could not chdir to '%s'", gitdirenv);
 680                        if (chdir(git_work_tree_cfg))
 681                                die_errno("Could not chdir to '%s'", git_work_tree_cfg);
 682                        core_worktree = xgetcwd();
 683                        if (chdir(cwd->buf))
 684                                die_errno("Could not come back to cwd");
 685                        set_git_work_tree(core_worktree);
 686                        free(core_worktree);
 687                }
 688        }
 689        else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {
 690                /* #16d */
 691                set_git_dir(gitdirenv);
 692                free(gitfile);
 693                return NULL;
 694        }
 695        else /* #2, #10 */
 696                set_git_work_tree(".");
 697
 698        /* set_git_work_tree() must have been called by now */
 699        worktree = get_git_work_tree();
 700
 701        /* both get_git_work_tree() and cwd are already normalized */
 702        if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */
 703                set_git_dir(gitdirenv);
 704                free(gitfile);
 705                return NULL;
 706        }
 707
 708        offset = dir_inside_of(cwd->buf, worktree);
 709        if (offset >= 0) {      /* cwd inside worktree? */
 710                set_git_dir(real_path(gitdirenv));
 711                if (chdir(worktree))
 712                        die_errno("Could not chdir to '%s'", worktree);
 713                strbuf_addch(cwd, '/');
 714                free(gitfile);
 715                return cwd->buf + offset;
 716        }
 717
 718        /* cwd outside worktree */
 719        set_git_dir(gitdirenv);
 720        free(gitfile);
 721        return NULL;
 722}
 723
 724static const char *setup_discovered_git_dir(const char *gitdir,
 725                                            struct strbuf *cwd, int offset,
 726                                            int *nongit_ok)
 727{
 728        if (check_repository_format_gently(gitdir, nongit_ok))
 729                return NULL;
 730
 731        /* --work-tree is set without --git-dir; use discovered one */
 732        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 733                char *to_free = NULL;
 734                const char *ret;
 735
 736                if (offset != cwd->len && !is_absolute_path(gitdir))
 737                        gitdir = to_free = real_pathdup(gitdir, 1);
 738                if (chdir(cwd->buf))
 739                        die_errno("Could not come back to cwd");
 740                ret = setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 741                free(to_free);
 742                return ret;
 743        }
 744
 745        /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
 746        if (is_bare_repository_cfg > 0) {
 747                set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));
 748                if (chdir(cwd->buf))
 749                        die_errno("Could not come back to cwd");
 750                return NULL;
 751        }
 752
 753        /* #0, #1, #5, #8, #9, #12, #13 */
 754        set_git_work_tree(".");
 755        if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))
 756                set_git_dir(gitdir);
 757        inside_git_dir = 0;
 758        inside_work_tree = 1;
 759        if (offset == cwd->len)
 760                return NULL;
 761
 762        /* Make "offset" point past the '/' (already the case for root dirs) */
 763        if (offset != offset_1st_component(cwd->buf))
 764                offset++;
 765        /* Add a '/' at the end */
 766        strbuf_addch(cwd, '/');
 767        return cwd->buf + offset;
 768}
 769
 770/* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
 771static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
 772                                      int *nongit_ok)
 773{
 774        int root_len;
 775
 776        if (check_repository_format_gently(".", nongit_ok))
 777                return NULL;
 778
 779        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 780
 781        /* --work-tree is set without --git-dir; use discovered one */
 782        if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
 783                static const char *gitdir;
 784
 785                gitdir = offset == cwd->len ? "." : xmemdupz(cwd->buf, offset);
 786                if (chdir(cwd->buf))
 787                        die_errno("Could not come back to cwd");
 788                return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
 789        }
 790
 791        inside_git_dir = 1;
 792        inside_work_tree = 0;
 793        if (offset != cwd->len) {
 794                if (chdir(cwd->buf))
 795                        die_errno("Cannot come back to cwd");
 796                root_len = offset_1st_component(cwd->buf);
 797                strbuf_setlen(cwd, offset > root_len ? offset : root_len);
 798                set_git_dir(cwd->buf);
 799        }
 800        else
 801                set_git_dir(".");
 802        return NULL;
 803}
 804
 805static const char *setup_nongit(const char *cwd, int *nongit_ok)
 806{
 807        if (!nongit_ok)
 808                die(_("Not a git repository (or any of the parent directories): %s"), DEFAULT_GIT_DIR_ENVIRONMENT);
 809        if (chdir(cwd))
 810                die_errno(_("Cannot come back to cwd"));
 811        *nongit_ok = 1;
 812        return NULL;
 813}
 814
 815static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
 816{
 817        struct stat buf;
 818        if (stat(path, &buf)) {
 819                die_errno("failed to stat '%*s%s%s'",
 820                                prefix_len,
 821                                prefix ? prefix : "",
 822                                prefix ? "/" : "", path);
 823        }
 824        return buf.st_dev;
 825}
 826
 827/*
 828 * A "string_list_each_func_t" function that canonicalizes an entry
 829 * from GIT_CEILING_DIRECTORIES using real_path_if_valid(), or
 830 * discards it if unusable.  The presence of an empty entry in
 831 * GIT_CEILING_DIRECTORIES turns off canonicalization for all
 832 * subsequent entries.
 833 */
 834static int canonicalize_ceiling_entry(struct string_list_item *item,
 835                                      void *cb_data)
 836{
 837        int *empty_entry_found = cb_data;
 838        char *ceil = item->string;
 839
 840        if (!*ceil) {
 841                *empty_entry_found = 1;
 842                return 0;
 843        } else if (!is_absolute_path(ceil)) {
 844                return 0;
 845        } else if (*empty_entry_found) {
 846                /* Keep entry but do not canonicalize it */
 847                return 1;
 848        } else {
 849                char *real_path = real_pathdup(ceil, 0);
 850                if (!real_path) {
 851                        return 0;
 852                }
 853                free(item->string);
 854                item->string = real_path;
 855                return 1;
 856        }
 857}
 858
 859enum discovery_result {
 860        GIT_DIR_NONE = 0,
 861        GIT_DIR_EXPLICIT,
 862        GIT_DIR_DISCOVERED,
 863        GIT_DIR_BARE,
 864        /* these are errors */
 865        GIT_DIR_HIT_CEILING = -1,
 866        GIT_DIR_HIT_MOUNT_POINT = -2,
 867        GIT_DIR_INVALID_GITFILE = -3
 868};
 869
 870/*
 871 * We cannot decide in this function whether we are in the work tree or
 872 * not, since the config can only be read _after_ this function was called.
 873 *
 874 * Also, we avoid changing any global state (such as the current working
 875 * directory) to allow early callers.
 876 *
 877 * The directory where the search should start needs to be passed in via the
 878 * `dir` parameter; upon return, the `dir` buffer will contain the path of
 879 * the directory where the search ended, and `gitdir` will contain the path of
 880 * the discovered .git/ directory, if any. If `gitdir` is not absolute, it
 881 * is relative to `dir` (i.e. *not* necessarily the cwd).
 882 */
 883static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,
 884                                                          struct strbuf *gitdir,
 885                                                          int die_on_error)
 886{
 887        const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
 888        struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
 889        const char *gitdirenv;
 890        int ceil_offset = -1, min_offset = has_dos_drive_prefix(dir->buf) ? 3 : 1;
 891        dev_t current_device = 0;
 892        int one_filesystem = 1;
 893
 894        /*
 895         * If GIT_DIR is set explicitly, we're not going
 896         * to do any discovery, but we still do repository
 897         * validation.
 898         */
 899        gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
 900        if (gitdirenv) {
 901                strbuf_addstr(gitdir, gitdirenv);
 902                return GIT_DIR_EXPLICIT;
 903        }
 904
 905        if (env_ceiling_dirs) {
 906                int empty_entry_found = 0;
 907
 908                string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
 909                filter_string_list(&ceiling_dirs, 0,
 910                                   canonicalize_ceiling_entry, &empty_entry_found);
 911                ceil_offset = longest_ancestor_length(dir->buf, &ceiling_dirs);
 912                string_list_clear(&ceiling_dirs, 0);
 913        }
 914
 915        if (ceil_offset < 0)
 916                ceil_offset = min_offset - 2;
 917
 918        /*
 919         * Test in the following order (relative to the dir):
 920         * - .git (file containing "gitdir: <path>")
 921         * - .git/
 922         * - ./ (bare)
 923         * - ../.git
 924         * - ../.git/
 925         * - ../ (bare)
 926         * - ../../.git/
 927         *   etc.
 928         */
 929        one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
 930        if (one_filesystem)
 931                current_device = get_device_or_die(dir->buf, NULL, 0);
 932        for (;;) {
 933                int offset = dir->len, error_code = 0;
 934
 935                if (offset > min_offset)
 936                        strbuf_addch(dir, '/');
 937                strbuf_addstr(dir, DEFAULT_GIT_DIR_ENVIRONMENT);
 938                gitdirenv = read_gitfile_gently(dir->buf, die_on_error ?
 939                                                NULL : &error_code);
 940                if (!gitdirenv) {
 941                        if (die_on_error ||
 942                            error_code == READ_GITFILE_ERR_NOT_A_FILE) {
 943                                /* NEEDSWORK: fail if .git is not file nor dir */
 944                                if (is_git_directory(dir->buf))
 945                                        gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
 946                        } else if (error_code != READ_GITFILE_ERR_STAT_FAILED)
 947                                return GIT_DIR_INVALID_GITFILE;
 948                }
 949                strbuf_setlen(dir, offset);
 950                if (gitdirenv) {
 951                        strbuf_addstr(gitdir, gitdirenv);
 952                        return GIT_DIR_DISCOVERED;
 953                }
 954
 955                if (is_git_directory(dir->buf)) {
 956                        strbuf_addstr(gitdir, ".");
 957                        return GIT_DIR_BARE;
 958                }
 959
 960                if (offset <= min_offset)
 961                        return GIT_DIR_HIT_CEILING;
 962
 963                while (--offset > ceil_offset && !is_dir_sep(dir->buf[offset]))
 964                        ; /* continue */
 965                if (offset <= ceil_offset)
 966                        return GIT_DIR_HIT_CEILING;
 967
 968                strbuf_setlen(dir, offset > min_offset ?  offset : min_offset);
 969                if (one_filesystem &&
 970                    current_device != get_device_or_die(dir->buf, NULL, offset))
 971                        return GIT_DIR_HIT_MOUNT_POINT;
 972        }
 973}
 974
 975int discover_git_directory(struct strbuf *commondir,
 976                           struct strbuf *gitdir)
 977{
 978        struct strbuf dir = STRBUF_INIT, err = STRBUF_INIT;
 979        size_t gitdir_offset = gitdir->len, cwd_len;
 980        size_t commondir_offset = commondir->len;
 981        struct repository_format candidate;
 982
 983        if (strbuf_getcwd(&dir))
 984                return -1;
 985
 986        cwd_len = dir.len;
 987        if (setup_git_directory_gently_1(&dir, gitdir, 0) <= 0) {
 988                strbuf_release(&dir);
 989                return -1;
 990        }
 991
 992        /*
 993         * The returned gitdir is relative to dir, and if dir does not reflect
 994         * the current working directory, we simply make the gitdir absolute.
 995         */
 996        if (dir.len < cwd_len && !is_absolute_path(gitdir->buf + gitdir_offset)) {
 997                /* Avoid a trailing "/." */
 998                if (!strcmp(".", gitdir->buf + gitdir_offset))
 999                        strbuf_setlen(gitdir, gitdir_offset);
1000                else
1001                        strbuf_addch(&dir, '/');
1002                strbuf_insert(gitdir, gitdir_offset, dir.buf, dir.len);
1003        }
1004
1005        get_common_dir(commondir, gitdir->buf + gitdir_offset);
1006
1007        strbuf_reset(&dir);
1008        strbuf_addf(&dir, "%s/config", commondir->buf + commondir_offset);
1009        read_repository_format(&candidate, dir.buf);
1010        strbuf_release(&dir);
1011
1012        if (verify_repository_format(&candidate, &err) < 0) {
1013                warning("ignoring git dir '%s': %s",
1014                        gitdir->buf + gitdir_offset, err.buf);
1015                strbuf_release(&err);
1016                strbuf_setlen(commondir, commondir_offset);
1017                strbuf_setlen(gitdir, gitdir_offset);
1018                return -1;
1019        }
1020
1021        return 0;
1022}
1023
1024const char *setup_git_directory_gently(int *nongit_ok)
1025{
1026        static struct strbuf cwd = STRBUF_INIT;
1027        struct strbuf dir = STRBUF_INIT, gitdir = STRBUF_INIT;
1028        const char *prefix;
1029
1030        /*
1031         * We may have read an incomplete configuration before
1032         * setting-up the git directory. If so, clear the cache so
1033         * that the next queries to the configuration reload complete
1034         * configuration (including the per-repo config file that we
1035         * ignored previously).
1036         */
1037        git_config_clear();
1038
1039        /*
1040         * Let's assume that we are in a git repository.
1041         * If it turns out later that we are somewhere else, the value will be
1042         * updated accordingly.
1043         */
1044        if (nongit_ok)
1045                *nongit_ok = 0;
1046
1047        if (strbuf_getcwd(&cwd))
1048                die_errno(_("Unable to read current working directory"));
1049        strbuf_addbuf(&dir, &cwd);
1050
1051        switch (setup_git_directory_gently_1(&dir, &gitdir, 1)) {
1052        case GIT_DIR_NONE:
1053                prefix = NULL;
1054                break;
1055        case GIT_DIR_EXPLICIT:
1056                prefix = setup_explicit_git_dir(gitdir.buf, &cwd, nongit_ok);
1057                break;
1058        case GIT_DIR_DISCOVERED:
1059                if (dir.len < cwd.len && chdir(dir.buf))
1060                        die(_("Cannot change to '%s'"), dir.buf);
1061                prefix = setup_discovered_git_dir(gitdir.buf, &cwd, dir.len,
1062                                                  nongit_ok);
1063                break;
1064        case GIT_DIR_BARE:
1065                if (dir.len < cwd.len && chdir(dir.buf))
1066                        die(_("Cannot change to '%s'"), dir.buf);
1067                prefix = setup_bare_git_dir(&cwd, dir.len, nongit_ok);
1068                break;
1069        case GIT_DIR_HIT_CEILING:
1070                prefix = setup_nongit(cwd.buf, nongit_ok);
1071                break;
1072        case GIT_DIR_HIT_MOUNT_POINT:
1073                if (nongit_ok) {
1074                        *nongit_ok = 1;
1075                        strbuf_release(&cwd);
1076                        strbuf_release(&dir);
1077                        return NULL;
1078                }
1079                die(_("Not a git repository (or any parent up to mount point %s)\n"
1080                      "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
1081                    dir.buf);
1082        default:
1083                die("BUG: unhandled setup_git_directory_1() result");
1084        }
1085
1086        if (prefix)
1087                setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
1088        else
1089                setenv(GIT_PREFIX_ENVIRONMENT, "", 1);
1090
1091        startup_info->have_repository = !nongit_ok || !*nongit_ok;
1092        startup_info->prefix = prefix;
1093
1094        /*
1095         * Not all paths through the setup code will call 'set_git_dir()' (which
1096         * directly sets up the environment) so in order to guarantee that the
1097         * environment is in a consistent state after setup, explicitly setup
1098         * the environment if we have a repository.
1099         *
1100         * NEEDSWORK: currently we allow bogus GIT_DIR values to be set in some
1101         * code paths so we also need to explicitly setup the environment if
1102         * the user has set GIT_DIR.  It may be beneficial to disallow bogus
1103         * GIT_DIR values at some point in the future.
1104         */
1105        if (startup_info->have_repository || getenv(GIT_DIR_ENVIRONMENT)) {
1106                if (!the_repository->gitdir) {
1107                        const char *gitdir = getenv(GIT_DIR_ENVIRONMENT);
1108                        if (!gitdir)
1109                                gitdir = DEFAULT_GIT_DIR_ENVIRONMENT;
1110                        repo_set_gitdir(the_repository, gitdir);
1111                        setup_git_env();
1112                }
1113        }
1114
1115        strbuf_release(&dir);
1116        strbuf_release(&gitdir);
1117
1118        return prefix;
1119}
1120
1121int git_config_perm(const char *var, const char *value)
1122{
1123        int i;
1124        char *endptr;
1125
1126        if (value == NULL)
1127                return PERM_GROUP;
1128
1129        if (!strcmp(value, "umask"))
1130                return PERM_UMASK;
1131        if (!strcmp(value, "group"))
1132                return PERM_GROUP;
1133        if (!strcmp(value, "all") ||
1134            !strcmp(value, "world") ||
1135            !strcmp(value, "everybody"))
1136                return PERM_EVERYBODY;
1137
1138        /* Parse octal numbers */
1139        i = strtol(value, &endptr, 8);
1140
1141        /* If not an octal number, maybe true/false? */
1142        if (*endptr != 0)
1143                return git_config_bool(var, value) ? PERM_GROUP : PERM_UMASK;
1144
1145        /*
1146         * Treat values 0, 1 and 2 as compatibility cases, otherwise it is
1147         * a chmod value to restrict to.
1148         */
1149        switch (i) {
1150        case PERM_UMASK:               /* 0 */
1151                return PERM_UMASK;
1152        case OLD_PERM_GROUP:           /* 1 */
1153                return PERM_GROUP;
1154        case OLD_PERM_EVERYBODY:       /* 2 */
1155                return PERM_EVERYBODY;
1156        }
1157
1158        /* A filemode value was given: 0xxx */
1159
1160        if ((i & 0600) != 0600)
1161                die(_("Problem with core.sharedRepository filemode value "
1162                    "(0%.3o).\nThe owner of files must always have "
1163                    "read and write permissions."), i);
1164
1165        /*
1166         * Mask filemode value. Others can not get write permission.
1167         * x flags for directories are handled separately.
1168         */
1169        return -(i & 0666);
1170}
1171
1172void check_repository_format(void)
1173{
1174        check_repository_format_gently(get_git_dir(), NULL);
1175        startup_info->have_repository = 1;
1176}
1177
1178/*
1179 * Returns the "prefix", a path to the current working directory
1180 * relative to the work tree root, or NULL, if the current working
1181 * directory is not a strict subdirectory of the work tree root. The
1182 * prefix always ends with a '/' character.
1183 */
1184const char *setup_git_directory(void)
1185{
1186        return setup_git_directory_gently(NULL);
1187}
1188
1189const char *resolve_gitdir_gently(const char *suspect, int *return_error_code)
1190{
1191        if (is_git_directory(suspect))
1192                return suspect;
1193        return read_gitfile_gently(suspect, return_error_code);
1194}
1195
1196/* if any standard file descriptor is missing open it to /dev/null */
1197void sanitize_stdfds(void)
1198{
1199        int fd = open("/dev/null", O_RDWR, 0);
1200        while (fd != -1 && fd < 2)
1201                fd = dup(fd);
1202        if (fd == -1)
1203                die_errno("open /dev/null or dup failed");
1204        if (fd > 2)
1205                close(fd);
1206}
1207
1208int daemonize(void)
1209{
1210#ifdef NO_POSIX_GOODIES
1211        errno = ENOSYS;
1212        return -1;
1213#else
1214        switch (fork()) {
1215                case 0:
1216                        break;
1217                case -1:
1218                        die_errno("fork failed");
1219                default:
1220                        exit(0);
1221        }
1222        if (setsid() == -1)
1223                die_errno("setsid failed");
1224        close(0);
1225        close(1);
1226        close(2);
1227        sanitize_stdfds();
1228        return 0;
1229#endif
1230}