+static int rollback_is_safe(void)
+{
+ struct strbuf sb = STRBUF_INIT;
+ struct object_id expected_head, actual_head;
+
+ if (strbuf_read_file(&sb, git_path_abort_safety_file(), 0) >= 0) {
+ strbuf_trim(&sb);
+ if (get_oid_hex(sb.buf, &expected_head)) {
+ strbuf_release(&sb);
+ die(_("could not parse %s"), git_path_abort_safety_file());
+ }
+ strbuf_release(&sb);
+ }
+ else if (errno == ENOENT)
+ oidclr(&expected_head);
+ else
+ die_errno(_("could not read '%s'"), git_path_abort_safety_file());
+
+ if (get_oid("HEAD", &actual_head))
+ oidclr(&actual_head);
+
+ return !oidcmp(&actual_head, &expected_head);
+}
+