- /* If that didn't work either, see if we are running in a
- * container, and a machine ID was passed in via
- * $container_uuid the way libvirt/LXC does it */
-
- r = detect_container(NULL);
- if (r > 0) {
- FILE *f;
-
- f = fopen("/proc/1/environ", "re");
- if (f) {
- bool done = false;
-
- do {
- char line[LINE_MAX];
- unsigned i;
-
- for (i = 0; i < sizeof(line)-1; i++) {
- int c;
-
- c = getc(f);
- if (_unlikely_(c == EOF)) {
- done = true;
- break;
- } else if (c == 0)
- break;
-
- line[i] = c;
- }
- line[i] = 0;
-
- if (startswith(line, "container_uuid=") &&
- strlen(line + 15) >= 36) {
- r = shorten_uuid(id, line + 15);
+ if (isempty(root)) {
+ /* If that didn't work, see if we are running in a container,
+ * and a machine ID was passed in via $container_uuid the way
+ * libvirt/LXC does it */
+ r = detect_container(NULL);
+ if (r > 0) {
+ _cleanup_free_ char *e = NULL;
+
+ r = getenv_for_pid(1, "container_uuid", &e);
+ if (r > 0) {
+ if (strlen(e) >= 36) {
+ r = shorten_uuid(id, e);