builtin/init-db.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "cache.h"
   7 #include "abspath.h"
   8 #include "config.h"
   9 #include "environment.h"
  10 #include "gettext.h"
  11 #include "refs.h"
  12 #include "builtin.h"
  13 #include "exec-cmd.h"
  14 #include "object-file.h"
  15 #include "parse-options.h"
  16 #include "setup.h"
  17 #include "worktree.h"
  18 #include "wrapper.h"
  19
  20 #ifndef DEFAULT_GIT_TEMPLATE_DIR
  21 #define DEFAULT_GIT_TEMPLATE_DIR "/usr/share/git-core/templates"
  22 #endif
  23
  24 #ifdef NO_TRUSTABLE_FILEMODE
  25 #define TEST_FILEMODE 0
  26 #else
  27 #define TEST_FILEMODE 1
  28 #endif
  29
  30 #define GIT_DEFAULT_HASH_ENVIRONMENT "GIT_DEFAULT_HASH"
  31
  32 static int init_is_bare_repository = 0;
  33 static int init_shared_repository = -1;
  34
  35 static void copy_templates_1(struct strbuf *path, struct strbuf *template_path,
  36                              DIR *dir)
  37 {
  38         size_t path_baselen = path->len;
  39         size_t template_baselen = template_path->len;
  40         struct dirent *de;
  41
  42         /* Note: if ".git/hooks" file exists in the repository being
  43          * re-initialized, /etc/core-git/templates/hooks/update would
  44          * cause "git init" to fail here.  I think this is sane but
  45          * it means that the set of templates we ship by default, along
  46          * with the way the namespace under .git/ is organized, should
  47          * be really carefully chosen.
  48          */
  49         safe_create_dir(path->buf, 1);
  50         while ((de = readdir(dir)) != NULL) {
  51                 struct stat st_git, st_template;
  52                 int exists = 0;
  53
  54                 strbuf_setlen(path, path_baselen);
  55                 strbuf_setlen(template_path, template_baselen);
  56
  57                 if (de->d_name[0] == '.')
  58                         continue;
  59                 strbuf_addstr(path, de->d_name);
  60                 strbuf_addstr(template_path, de->d_name);
  61                 if (lstat(path->buf, &st_git)) {
  62                         if (errno != ENOENT)
  63                                 die_errno(_("cannot stat '%s'"), path->buf);
  64                 }
  65                 else
  66                         exists = 1;
  67
  68                 if (lstat(template_path->buf, &st_template))
  69                         die_errno(_("cannot stat template '%s'"), template_path->buf);
  70
  71                 if (S_ISDIR(st_template.st_mode)) {
  72                         DIR *subdir = opendir(template_path->buf);
  73                         if (!subdir)
  74                                 die_errno(_("cannot opendir '%s'"), template_path->buf);
  75                         strbuf_addch(path, '/');
  76                         strbuf_addch(template_path, '/');
  77                         copy_templates_1(path, template_path, subdir);
  78                         closedir(subdir);
  79                 }
  80                 else if (exists)
  81                         continue;
  82                 else if (S_ISLNK(st_template.st_mode)) {
  83                         struct strbuf lnk = STRBUF_INIT;
  84                         if (strbuf_readlink(&lnk, template_path->buf,
  85                                             st_template.st_size) < 0)
  86                                 die_errno(_("cannot readlink '%s'"), template_path->buf);
  87                         if (symlink(lnk.buf, path->buf))
  88                                 die_errno(_("cannot symlink '%s' '%s'"),
  89                                           lnk.buf, path->buf);
  90                         strbuf_release(&lnk);
  91                 }
  92                 else if (S_ISREG(st_template.st_mode)) {
  93                         if (copy_file(path->buf, template_path->buf, st_template.st_mode))
  94                                 die_errno(_("cannot copy '%s' to '%s'"),
  95                                           template_path->buf, path->buf);
  96                 }
  97                 else
  98                         error(_("ignoring template %s"), template_path->buf);
  99         }
 100 }
 101
 102 static void copy_templates(const char *template_dir, const char *init_template_dir)
 103 {
 104         struct strbuf path = STRBUF_INIT;
 105         struct strbuf template_path = STRBUF_INIT;
 106         size_t template_len;
 107         struct repository_format template_format = REPOSITORY_FORMAT_INIT;
 108         struct strbuf err = STRBUF_INIT;
 109         DIR *dir;
 110         char *to_free = NULL;
 111
 112         if (!template_dir)
 113                 template_dir = getenv(TEMPLATE_DIR_ENVIRONMENT);
 114         if (!template_dir)
 115                 template_dir = init_template_dir;
 116         if (!template_dir)
 117                 template_dir = to_free = system_path(DEFAULT_GIT_TEMPLATE_DIR);
 118         if (!template_dir[0]) {
 119                 free(to_free);
 120                 return;
 121         }
 122
 123         strbuf_addstr(&template_path, template_dir);
 124         strbuf_complete(&template_path, '/');
 125         template_len = template_path.len;
 126
 127         dir = opendir(template_path.buf);
 128         if (!dir) {
 129                 warning(_("templates not found in %s"), template_dir);
 130                 goto free_return;
 131         }
 132
 133         /* Make sure that template is from the correct vintage */
 134         strbuf_addstr(&template_path, "config");
 135         read_repository_format(&template_format, template_path.buf);
 136         strbuf_setlen(&template_path, template_len);
 137
 138         /*
 139          * No mention of version at all is OK, but anything else should be
 140          * verified.
 141          */
 142         if (template_format.version >= 0 &&
 143             verify_repository_format(&template_format, &err) < 0) {
 144                 warning(_("not copying templates from '%s': %s"),
 145                           template_dir, err.buf);
 146                 strbuf_release(&err);
 147                 goto close_free_return;
 148         }
 149
 150         strbuf_addstr(&path, get_git_common_dir());
 151         strbuf_complete(&path, '/');
 152         copy_templates_1(&path, &template_path, dir);
 153 close_free_return:
 154         closedir(dir);
 155 free_return:
 156         free(to_free);
 157         strbuf_release(&path);
 158         strbuf_release(&template_path);
 159         clear_repository_format(&template_format);
 160 }
 161
 162 /*
 163  * If the git_dir is not directly inside the working tree, then git will not
 164  * find it by default, and we need to set the worktree explicitly.
 165  */
 166 static int needs_work_tree_config(const char *git_dir, const char *work_tree)
 167 {
 168         if (!strcmp(work_tree, "/") && !strcmp(git_dir, "/.git"))
 169                 return 0;
 170         if (skip_prefix(git_dir, work_tree, &git_dir) &&
 171             !strcmp(git_dir, "/.git"))
 172                 return 0;
 173         return 1;
 174 }
 175
 176 void initialize_repository_version(int hash_algo, int reinit)
 177 {
 178         char repo_version_string[10];
 179         int repo_version = GIT_REPO_VERSION;
 180
 181         if (hash_algo != GIT_HASH_SHA1)
 182                 repo_version = GIT_REPO_VERSION_READ;
 183
 184         /* This forces creation of new config file */
 185         xsnprintf(repo_version_string, sizeof(repo_version_string),
 186                   "%d", repo_version);
 187         git_config_set("core.repositoryformatversion", repo_version_string);
 188
 189         if (hash_algo != GIT_HASH_SHA1)
 190                 git_config_set("extensions.objectformat",
 191                                hash_algos[hash_algo].name);
 192         else if (reinit)
 193                 git_config_set_gently("extensions.objectformat", NULL);
 194 }
 195
 196 static int create_default_files(const char *template_path,
 197                                 const char *original_git_dir,
 198                                 const char *initial_branch,
 199                                 const struct repository_format *fmt,
 200                                 int quiet)
 201 {
 202         struct stat st1;
 203         struct strbuf buf = STRBUF_INIT;
 204         char *path;
 205         char junk[2];
 206         int reinit;
 207         int filemode;
 208         struct strbuf err = STRBUF_INIT;
 209         const char *init_template_dir = NULL;
 210         const char *work_tree = get_git_work_tree();
 211
 212         /*
 213          * First copy the templates -- we might have the default
 214          * config file there, in which case we would want to read
 215          * from it after installing.
 216          *
 217          * Before reading that config, we also need to clear out any cached
 218          * values (since we've just potentially changed what's available on
 219          * disk).
 220          */
 221         git_config_get_pathname("init.templatedir", &init_template_dir);
 222         copy_templates(template_path, init_template_dir);
 223         free((char *)init_template_dir);
 224         git_config_clear();
 225         reset_shared_repository();
 226         git_config(git_default_config, NULL);
 227
 228         /*
 229          * We must make sure command-line options continue to override any
 230          * values we might have just re-read from the config.
 231          */
 232         is_bare_repository_cfg = init_is_bare_repository || !work_tree;
 233         if (init_shared_repository != -1)
 234                 set_shared_repository(init_shared_repository);
 235
 236         /*
 237          * We would have created the above under user's umask -- under
 238          * shared-repository settings, we would need to fix them up.
 239          */
 240         if (get_shared_repository()) {
 241                 adjust_shared_perm(get_git_dir());
 242         }
 243
 244         /*
 245          * We need to create a "refs" dir in any case so that older
 246          * versions of git can tell that this is a repository.
 247          */
 248         safe_create_dir(git_path("refs"), 1);
 249         adjust_shared_perm(git_path("refs"));
 250
 251         if (refs_init_db(&err))
 252                 die("failed to set up refs db: %s", err.buf);
 253
 254         /*
 255          * Point the HEAD symref to the initial branch with if HEAD does
 256          * not yet exist.
 257          */
 258         path = git_path_buf(&buf, "HEAD");
 259         reinit = (!access(path, R_OK)
 260                   || readlink(path, junk, sizeof(junk)-1) != -1);
 261         if (!reinit) {
 262                 char *ref;
 263
 264                 if (!initial_branch)
 265                         initial_branch = git_default_branch_name(quiet);
 266
 267                 ref = xstrfmt("refs/heads/%s", initial_branch);
 268                 if (check_refname_format(ref, 0) < 0)
 269                         die(_("invalid initial branch name: '%s'"),
 270                             initial_branch);
 271
 272                 if (create_symref("HEAD", ref, NULL) < 0)
 273                         exit(1);
 274                 free(ref);
 275         }
 276
 277         initialize_repository_version(fmt->hash_algo, 0);
 278
 279         /* Check filemode trustability */
 280         path = git_path_buf(&buf, "config");
 281         filemode = TEST_FILEMODE;
 282         if (TEST_FILEMODE && !lstat(path, &st1)) {
 283                 struct stat st2;
 284                 filemode = (!chmod(path, st1.st_mode ^ S_IXUSR) &&
 285                                 !lstat(path, &st2) &&
 286                                 st1.st_mode != st2.st_mode &&
 287                                 !chmod(path, st1.st_mode));
 288                 if (filemode && !reinit && (st1.st_mode & S_IXUSR))
 289                         filemode = 0;
 290         }
 291         git_config_set("core.filemode", filemode ? "true" : "false");
 292
 293         if (is_bare_repository())
 294                 git_config_set("core.bare", "true");
 295         else {
 296                 git_config_set("core.bare", "false");
 297                 /* allow template config file to override the default */
 298                 if (log_all_ref_updates == LOG_REFS_UNSET)
 299                         git_config_set("core.logallrefupdates", "true");
 300                 if (needs_work_tree_config(original_git_dir, work_tree))
 301                         git_config_set("core.worktree", work_tree);
 302         }
 303
 304         if (!reinit) {
 305                 /* Check if symlink is supported in the work tree */
 306                 path = git_path_buf(&buf, "tXXXXXX");
 307                 if (!close(xmkstemp(path)) &&
 308                     !unlink(path) &&
 309                     !symlink("testing", path) &&
 310                     !lstat(path, &st1) &&
 311                     S_ISLNK(st1.st_mode))
 312                         unlink(path); /* good */
 313                 else
 314                         git_config_set("core.symlinks", "false");
 315
 316                 /* Check if the filesystem is case-insensitive */
 317                 path = git_path_buf(&buf, "CoNfIg");
 318                 if (!access(path, F_OK))
 319                         git_config_set("core.ignorecase", "true");
 320                 probe_utf8_pathname_composition();
 321         }
 322
 323         strbuf_release(&buf);
 324         return reinit;
 325 }
 326
 327 static void create_object_directory(void)
 328 {
 329         struct strbuf path = STRBUF_INIT;
 330         size_t baselen;
 331
 332         strbuf_addstr(&path, get_object_directory());
 333         baselen = path.len;
 334
 335         safe_create_dir(path.buf, 1);
 336
 337         strbuf_setlen(&path, baselen);
 338         strbuf_addstr(&path, "/pack");
 339         safe_create_dir(path.buf, 1);
 340
 341         strbuf_setlen(&path, baselen);
 342         strbuf_addstr(&path, "/info");
 343         safe_create_dir(path.buf, 1);
 344
 345         strbuf_release(&path);
 346 }
 347
 348 static void separate_git_dir(const char *git_dir, const char *git_link)
 349 {
 350         struct stat st;
 351
 352         if (!stat(git_link, &st)) {
 353                 const char *src;
 354
 355                 if (S_ISREG(st.st_mode))
 356                         src = read_gitfile(git_link);
 357                 else if (S_ISDIR(st.st_mode))
 358                         src = git_link;
 359                 else
 360                         die(_("unable to handle file type %d"), (int)st.st_mode);
 361
 362                 if (rename(src, git_dir))
 363                         die_errno(_("unable to move %s to %s"), src, git_dir);
 364                 repair_worktrees(NULL, NULL);
 365         }
 366
 367         write_file(git_link, "gitdir: %s", git_dir);
 368 }
 369
 370 static void validate_hash_algorithm(struct repository_format *repo_fmt, int hash)
 371 {
 372         const char *env = getenv(GIT_DEFAULT_HASH_ENVIRONMENT);
 373         /*
 374          * If we already have an initialized repo, don't allow the user to
 375          * specify a different algorithm, as that could cause corruption.
 376          * Otherwise, if the user has specified one on the command line, use it.
 377          */
 378         if (repo_fmt->version >= 0 && hash != GIT_HASH_UNKNOWN && hash != repo_fmt->hash_algo)
 379                 die(_("attempt to reinitialize repository with different hash"));
 380         else if (hash != GIT_HASH_UNKNOWN)
 381                 repo_fmt->hash_algo = hash;
 382         else if (env) {
 383                 int env_algo = hash_algo_by_name(env);
 384                 if (env_algo == GIT_HASH_UNKNOWN)
 385                         die(_("unknown hash algorithm '%s'"), env);
 386                 repo_fmt->hash_algo = env_algo;
 387         }
 388 }
 389
 390 int init_db(const char *git_dir, const char *real_git_dir,
 391             const char *template_dir, int hash, const char *initial_branch,
 392             unsigned int flags)
 393 {
 394         int reinit;
 395         int exist_ok = flags & INIT_DB_EXIST_OK;
 396         char *original_git_dir = real_pathdup(git_dir, 1);
 397         struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
 398
 399         if (real_git_dir) {
 400                 struct stat st;
 401
 402                 if (!exist_ok && !stat(git_dir, &st))
 403                         die(_("%s already exists"), git_dir);
 404
 405                 if (!exist_ok && !stat(real_git_dir, &st))
 406                         die(_("%s already exists"), real_git_dir);
 407
 408                 set_git_dir(real_git_dir, 1);
 409                 git_dir = get_git_dir();
 410                 separate_git_dir(git_dir, original_git_dir);
 411         }
 412         else {
 413                 set_git_dir(git_dir, 1);
 414                 git_dir = get_git_dir();
 415         }
 416         startup_info->have_repository = 1;
 417
 418         /* Ensure `core.hidedotfiles` is processed */
 419         git_config(platform_core_config, NULL);
 420
 421         safe_create_dir(git_dir, 0);
 422
 423         init_is_bare_repository = is_bare_repository();
 424
 425         /* Check to see if the repository version is right.
 426          * Note that a newly created repository does not have
 427          * config file, so this will not fail.  What we are catching
 428          * is an attempt to reinitialize new repository with an old tool.
 429          */
 430         check_repository_format(&repo_fmt);
 431
 432         validate_hash_algorithm(&repo_fmt, hash);
 433
 434         reinit = create_default_files(template_dir, original_git_dir,
 435                                       initial_branch, &repo_fmt,
 436                                       flags & INIT_DB_QUIET);
 437         if (reinit && initial_branch)
 438                 warning(_("re-init: ignored --initial-branch=%s"),
 439                         initial_branch);
 440
 441         create_object_directory();
 442
 443         if (get_shared_repository()) {
 444                 char buf[10];
 445                 /* We do not spell "group" and such, so that
 446                  * the configuration can be read by older version
 447                  * of git. Note, we use octal numbers for new share modes,
 448                  * and compatibility values for PERM_GROUP and
 449                  * PERM_EVERYBODY.
 450                  */
 451                 if (get_shared_repository() < 0)
 452                         /* force to the mode value */
 453                         xsnprintf(buf, sizeof(buf), "0%o", -get_shared_repository());
 454                 else if (get_shared_repository() == PERM_GROUP)
 455                         xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_GROUP);
 456                 else if (get_shared_repository() == PERM_EVERYBODY)
 457                         xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_EVERYBODY);
 458                 else
 459                         BUG("invalid value for shared_repository");
 460                 git_config_set("core.sharedrepository", buf);
 461                 git_config_set("receive.denyNonFastforwards", "true");
 462         }
 463
 464         if (!(flags & INIT_DB_QUIET)) {
 465                 int len = strlen(git_dir);
 466
 467                 if (reinit)
 468                         printf(get_shared_repository()
 469                                ? _("Reinitialized existing shared Git repository in %s%s\n")
 470                                : _("Reinitialized existing Git repository in %s%s\n"),
 471                                git_dir, len && git_dir[len-1] != '/' ? "/" : "");
 472                 else
 473                         printf(get_shared_repository()
 474                                ? _("Initialized empty shared Git repository in %s%s\n")
 475                                : _("Initialized empty Git repository in %s%s\n"),
 476                                git_dir, len && git_dir[len-1] != '/' ? "/" : "");
 477         }
 478
 479         free(original_git_dir);
 480         return 0;
 481 }
 482
 483 static int guess_repository_type(const char *git_dir)
 484 {
 485         const char *slash;
 486         char *cwd;
 487         int cwd_is_git_dir;
 488
 489         /*
 490          * "GIT_DIR=. git init" is always bare.
 491          * "GIT_DIR=`pwd` git init" too.
 492          */
 493         if (!strcmp(".", git_dir))
 494                 return 1;
 495         cwd = xgetcwd();
 496         cwd_is_git_dir = !strcmp(git_dir, cwd);
 497         free(cwd);
 498         if (cwd_is_git_dir)
 499                 return 1;
 500         /*
 501          * "GIT_DIR=.git or GIT_DIR=something/.git is usually not.
 502          */
 503         if (!strcmp(git_dir, ".git"))
 504                 return 0;
 505         slash = strrchr(git_dir, '/');
 506         if (slash && !strcmp(slash, "/.git"))
 507                 return 0;
 508
 509         /*
 510          * Otherwise it is often bare.  At this point
 511          * we are just guessing.
 512          */
 513         return 1;
 514 }
 515
 516 static int shared_callback(const struct option *opt, const char *arg, int unset)
 517 {
 518         BUG_ON_OPT_NEG(unset);
 519         *((int *) opt->value) = (arg) ? git_config_perm("arg", arg) : PERM_GROUP;
 520         return 0;
 521 }
 522
 523 static const char *const init_db_usage[] = {
 524         N_("git init [-q | --quiet] [--bare] [--template=<template-directory>]\n"
 525            "         [--separate-git-dir <git-dir>] [--object-format=<format>]\n"
 526            "         [-b <branch-name> | --initial-branch=<branch-name>]\n"
 527            "         [--shared[=<permissions>]] [<directory>]"),
 528         NULL
 529 };
 530
 531 /*
 532  * If you want to, you can share the DB area with any number of branches.
 533  * That has advantages: you can save space by sharing all the SHA1 objects.
 534  * On the other hand, it might just make lookup slower and messier. You
 535  * be the judge.  The default case is to have one DB per managed directory.
 536  */
 537 int cmd_init_db(int argc, const char **argv, const char *prefix)
 538 {
 539         const char *git_dir;
 540         const char *real_git_dir = NULL;
 541         const char *work_tree;
 542         const char *template_dir = NULL;
 543         unsigned int flags = 0;
 544         const char *object_format = NULL;
 545         const char *initial_branch = NULL;
 546         int hash_algo = GIT_HASH_UNKNOWN;
 547         const struct option init_db_options[] = {
 548                 OPT_STRING(0, "template", &template_dir, N_("template-directory"),
 549                                 N_("directory from which templates will be used")),
 550                 OPT_SET_INT(0, "bare", &is_bare_repository_cfg,
 551                                 N_("create a bare repository"), 1),
 552                 { OPTION_CALLBACK, 0, "shared", &init_shared_repository,
 553                         N_("permissions"),
 554                         N_("specify that the git repository is to be shared amongst several users"),
 555                         PARSE_OPT_OPTARG | PARSE_OPT_NONEG, shared_callback, 0},
 556                 OPT_BIT('q', "quiet", &flags, N_("be quiet"), INIT_DB_QUIET),
 557                 OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
 558                            N_("separate git dir from working tree")),
 559                 OPT_STRING('b', "initial-branch", &initial_branch, N_("name"),
 560                            N_("override the name of the initial branch")),
 561                 OPT_STRING(0, "object-format", &object_format, N_("hash"),
 562                            N_("specify the hash algorithm to use")),
 563                 OPT_END()
 564         };
 565
 566         argc = parse_options(argc, argv, prefix, init_db_options, init_db_usage, 0);
 567
 568         if (real_git_dir && is_bare_repository_cfg == 1)
 569                 die(_("options '%s' and '%s' cannot be used together"), "--separate-git-dir", "--bare");
 570
 571         if (real_git_dir && !is_absolute_path(real_git_dir))
 572                 real_git_dir = real_pathdup(real_git_dir, 1);
 573
 574         if (template_dir && *template_dir && !is_absolute_path(template_dir)) {
 575                 template_dir = absolute_pathdup(template_dir);
 576                 UNLEAK(template_dir);
 577         }
 578
 579         if (argc == 1) {
 580                 int mkdir_tried = 0;
 581         retry:
 582                 if (chdir(argv[0]) < 0) {
 583                         if (!mkdir_tried) {
 584                                 int saved;
 585                                 /*
 586                                  * At this point we haven't read any configuration,
 587                                  * and we know shared_repository should always be 0;
 588                                  * but just in case we play safe.
 589                                  */
 590                                 saved = get_shared_repository();
 591                                 set_shared_repository(0);
 592                                 switch (safe_create_leading_directories_const(argv[0])) {
 593                                 case SCLD_OK:
 594                                 case SCLD_PERMS:
 595                                         break;
 596                                 case SCLD_EXISTS:
 597                                         errno = EEXIST;
 598                                         /* fallthru */
 599                                 default:
 600                                         die_errno(_("cannot mkdir %s"), argv[0]);
 601                                         break;
 602                                 }
 603                                 set_shared_repository(saved);
 604                                 if (mkdir(argv[0], 0777) < 0)
 605                                         die_errno(_("cannot mkdir %s"), argv[0]);
 606                                 mkdir_tried = 1;
 607                                 goto retry;
 608                         }
 609                         die_errno(_("cannot chdir to %s"), argv[0]);
 610                 }
 611         } else if (0 < argc) {
 612                 usage(init_db_usage[0]);
 613         }
 614         if (is_bare_repository_cfg == 1) {
 615                 char *cwd = xgetcwd();
 616                 setenv(GIT_DIR_ENVIRONMENT, cwd, argc > 0);
 617                 free(cwd);
 618         }
 619
 620         if (object_format) {
 621                 hash_algo = hash_algo_by_name(object_format);
 622                 if (hash_algo == GIT_HASH_UNKNOWN)
 623                         die(_("unknown hash algorithm '%s'"), object_format);
 624         }
 625
 626         if (init_shared_repository != -1)
 627                 set_shared_repository(init_shared_repository);
 628
 629         /*
 630          * GIT_WORK_TREE makes sense only in conjunction with GIT_DIR
 631          * without --bare.  Catch the error early.
 632          */
 633         git_dir = xstrdup_or_null(getenv(GIT_DIR_ENVIRONMENT));
 634         work_tree = xstrdup_or_null(getenv(GIT_WORK_TREE_ENVIRONMENT));
 635         if ((!git_dir || is_bare_repository_cfg == 1) && work_tree)
 636                 die(_("%s (or --work-tree=<directory>) not allowed without "
 637                           "specifying %s (or --git-dir=<directory>)"),
 638                     GIT_WORK_TREE_ENVIRONMENT,
 639                     GIT_DIR_ENVIRONMENT);
 640
 641         /*
 642          * Set up the default .git directory contents
 643          */
 644         if (!git_dir)
 645                 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
 646
 647         /*
 648          * When --separate-git-dir is used inside a linked worktree, take
 649          * care to ensure that the common .git/ directory is relocated, not
 650          * the worktree-specific .git/worktrees/<id>/ directory.
 651          */
 652         if (real_git_dir) {
 653                 int err;
 654                 const char *p;
 655                 struct strbuf sb = STRBUF_INIT;
 656
 657                 p = read_gitfile_gently(git_dir, &err);
 658                 if (p && get_common_dir(&sb, p)) {
 659                         struct strbuf mainwt = STRBUF_INIT;
 660
 661                         strbuf_addbuf(&mainwt, &sb);
 662                         strbuf_strip_suffix(&mainwt, "/.git");
 663                         if (chdir(mainwt.buf) < 0)
 664                                 die_errno(_("cannot chdir to %s"), mainwt.buf);
 665                         strbuf_release(&mainwt);
 666                         git_dir = strbuf_detach(&sb, NULL);
 667                 }
 668                 strbuf_release(&sb);
 669         }
 670
 671         if (is_bare_repository_cfg < 0)
 672                 is_bare_repository_cfg = guess_repository_type(git_dir);
 673
 674         if (!is_bare_repository_cfg) {
 675                 const char *git_dir_parent = strrchr(git_dir, '/');
 676                 if (git_dir_parent) {
 677                         char *rel = xstrndup(git_dir, git_dir_parent - git_dir);
 678                         git_work_tree_cfg = real_pathdup(rel, 1);
 679                         free(rel);
 680                 }
 681                 if (!git_work_tree_cfg)
 682                         git_work_tree_cfg = xgetcwd();
 683                 if (work_tree)
 684                         set_git_work_tree(work_tree);
 685                 else
 686                         set_git_work_tree(git_work_tree_cfg);
 687                 if (access(get_git_work_tree(), X_OK))
 688                         die_errno (_("Cannot access work tree '%s'"),
 689                                    get_git_work_tree());
 690         }
 691         else {
 692                 if (real_git_dir)
 693                         die(_("--separate-git-dir incompatible with bare repository"));
 694                 if (work_tree)
 695                         set_git_work_tree(work_tree);
 696         }
 697
 698         UNLEAK(real_git_dir);
 699         UNLEAK(git_dir);
 700         UNLEAK(work_tree);
 701
 702         flags |= INIT_DB_EXIST_OK;
 703         return init_db(git_dir, real_git_dir, template_dir, hash_algo,
 704                        initial_branch, flags);
 705 }