+ /* If that didn't work, see if we are running in qemu/kvm and a
+ * machine ID was passed in via -uuid on the qemu/kvm command
+ * line */
+
+ r = detect_vm(&vm_id);
+ if (r > 0 && streq(vm_id, "kvm")) {
+ char uuid[37];
+
+ fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+ if (fd >= 0) {
+ k = loop_read(fd, uuid, 36, false);
+ close_nointr_nofail(fd);
+
+ if (k >= 36) {
+ r = shorten_uuid(id, uuid);
+ if (r >= 0) {
+ log_info("Initializing machine ID from KVM UUID");
+ return 0;
+ }
+ }
+ }
+ }
+
+ /* 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 (r >= 0) {
+ log_info("Initializing machine ID from container UUID");
+ return 0;
+ }
+ }
+
+ } while (!done);
+
+ fclose(f);
+ }
+ }
+