main: introduce /etc/machine-id

This is supposed to play the same roles /var/lib/dbus/machine-id,
however fixes a couple of problems:

- It is available during early boot since it is stored in /etc

- Removes the ID from the D-Bus context and moves it into a system
  context, thus hopefully lowering hesitation by people to use it.

- It is generated at installation time. If the file is empty at boot
  time it will be mounted over with a randomly generated ID, which is
  not saved to disk. This is useful to support state-less machines with
  no transient or writable /etc configuration.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
index ef6e681771..a041a22eda 100644
--- a/src/main.c
+++ b/src/main.c
@@ -41,6 +41,7 @@
 #include "kmod-setup.h"
 #include "locale-setup.h"
 #include "selinux-setup.h"
+#include "machine-id-setup.h"
 #include "load-fragment.h"
 #include "fdset.h"
 #include "special.h"
@@ -1127,6 +1128,7 @@ int main(int argc, char *argv[]) {
 
                 kmod_setup();
                 hostname_setup();
+                machine_id_setup();
                 loopback_setup();
 
                 mkdir_p("/dev/.systemd/ask-password/", 0755);