+static const char *setup_explicit_git_dir(const char *gitdirenv,
+ const char *work_tree_env, int *nongit_ok)
+{
+ static char buffer[1024 + 1];
+ const char *retval;
+
+ if (PATH_MAX - 40 < strlen(gitdirenv))
+ die("'$%s' too big", GIT_DIR_ENVIRONMENT);
+ if (!is_git_directory(gitdirenv)) {
+ if (nongit_ok) {
+ *nongit_ok = 1;
+ return NULL;
+ }
+ die("Not a git repository: '%s'", gitdirenv);
+ }
+ if (!work_tree_env) {
+ retval = set_work_tree(gitdirenv);
+ /* config may override worktree */
+ if (check_repository_format_gently(nongit_ok))
+ return NULL;
+ return retval;
+ }
+ if (check_repository_format_gently(nongit_ok))
+ return NULL;
+ retval = get_relative_cwd(buffer, sizeof(buffer) - 1,
+ get_git_work_tree());
+ if (!retval || !*retval)
+ return NULL;
+ set_git_dir(make_absolute_path(gitdirenv));
+ if (chdir(work_tree_env) < 0)
+ die_errno ("Could not chdir to '%s'", work_tree_env);
+ strcat(buffer, "/");
+ return retval;
+}
+
+static int cwd_contains_git_dir(const char **gitfile_dirp)
+{
+ const char *gitfile_dir = read_gitfile_gently(DEFAULT_GIT_DIR_ENVIRONMENT);
+ *gitfile_dirp = gitfile_dir;
+ if (gitfile_dir) {
+ if (set_git_dir(gitfile_dir))
+ die("Repository setup failed");
+ return 1;
+ }
+ return is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT);
+}
+
+static const char *setup_discovered_git_dir(const char *work_tree_env,
+ int offset, int len, char *cwd, int *nongit_ok)
+{
+ int root_len;
+
+ inside_git_dir = 0;
+ if (!work_tree_env)
+ inside_work_tree = 1;
+ root_len = offset_1st_component(cwd);
+ git_work_tree_cfg = xstrndup(cwd, offset > root_len ? offset : root_len);
+ if (check_repository_format_gently(nongit_ok))
+ return NULL;
+ if (offset == len)
+ return NULL;
+
+ /* Make "offset" point to past the '/', and add a '/' at the end */
+ offset++;
+ cwd[len++] = '/';
+ cwd[len] = 0;
+ return cwd + offset;
+}
+
+static const char *setup_bare_git_dir(const char *work_tree_env,
+ int offset, int len, char *cwd, int *nongit_ok)
+{
+ int root_len;
+
+ inside_git_dir = 1;
+ if (!work_tree_env)
+ inside_work_tree = 0;
+ if (offset != len) {
+ if (chdir(cwd))
+ die_errno("Cannot come back to cwd");
+ root_len = offset_1st_component(cwd);
+ cwd[offset > root_len ? offset : root_len] = '\0';
+ set_git_dir(cwd);
+ } else
+ set_git_dir(".");
+ check_repository_format_gently(nongit_ok);
+ return NULL;
+}
+
+static const char *setup_nongit(const char *cwd, int *nongit_ok)
+{
+ if (!nongit_ok)
+ die("Not a git repository (or any of the parent directories): %s", DEFAULT_GIT_DIR_ENVIRONMENT);
+ if (chdir(cwd))
+ die_errno("Cannot come back to cwd");
+ *nongit_ok = 1;
+ return NULL;
+}
+
+static dev_t get_device_or_die(const char *path, const char *prefix)
+{
+ struct stat buf;
+ if (stat(path, &buf))
+ die_errno("failed to stat '%s%s%s'",
+ prefix ? prefix : "",
+ prefix ? "/" : "", path);
+ return buf.st_dev;
+}
+