+int unit_write_drop_in(Unit *u, bool runtime, const char *name, const char *data) {
+ _cleanup_free_ char *p = NULL, *q = NULL;
+ assert(u);
+
+ if (u->manager->running_as != SYSTEMD_SYSTEM)
+ return -ENOTSUP;
+
+ if (!filename_is_safe(name))
+ return -EINVAL;
+
+ p = strjoin(runtime ? "/run/systemd/system/" : "/etc/systemd/systemd/", u->id, ".d", NULL);
+ if (!p)
+ return -ENOMEM;
+
+ q = strjoin(p, "/50-", name, ".conf", NULL);
+ if (!q)
+ return -ENOMEM;
+
+ mkdir_p(p, 0755);
+ return write_one_line_file_atomic(q, data);
+}
+
+int unit_remove_drop_in(Unit *u, bool runtime, const char *name) {
+ _cleanup_free_ char *p = NULL, *q = NULL;
+
+ assert(u);
+
+ if (u->manager->running_as != SYSTEMD_SYSTEM)
+ return -ENOTSUP;
+
+ if (!filename_is_safe(name))
+ return -EINVAL;
+
+ p = strjoin(runtime ? "/run/systemd/system/" : "/etc/systemd/systemd/", u->id, ".d", NULL);
+ if (!p)
+ return -ENOMEM;
+
+ q = strjoin(p, "/50-", name, ".conf", NULL);
+ if (!q)
+ return -ENOMEM;
+
+ if (unlink(q) < 0)
+ return -errno;
+
+ rmdir(p);
+ return 0;
+}
+