int machine_id_setup(const char *root) {
const char *etc_machine_id, *run_machine_id;
_cleanup_close_ int fd = -1;
- bool writable = false;
+ bool writable = true;
struct stat st;
char id[34]; /* 32 + \n + \0 */
int r;
mkdir_parents(etc_machine_id, 0755);
fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
- if (fd >= 0)
- writable = true;
- else {
+ if (fd < 0) {
+ int old_errno = errno;
+
fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
- log_error("Cannot open %s: %m", etc_machine_id);
+ if (old_errno == EROFS && errno == ENOENT)
+ log_error("System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n"
+ "Booting up is supported only when:\n"
+ "1) /etc/machine-id exists and is populated.\n"
+ "2) /etc/machine-id exists and is empty.\n"
+ "3) /etc/machine-id is missing and /etc is writable.\n");
+ else
+ log_error("Cannot open %s: %m", etc_machine_id);
return -errno;
}