ostree-prepare-root as init: exec init from deployment if run as PID1

This supports running ostree on embedded platforms without an initrd.
Specificially I'm trying to do bringup on an NVidia Tegra based Jetson TK1
dev board.

Closes: #403
Approved by: cgwalters

diff --git a/src/switchroot/ostree-prepare-root.c b/src/switchroot/ostree-prepare-root.c
index df3e32198fc260c0b98bdfdc6db4ab8bc65775fc..a233007ef6e894a826427451d2ba299c3c10175b 100644 (file)
--- a/src/switchroot/ostree-prepare-root.c
+++ b/src/switchroot/ostree-prepare-root.c
@@ -156,12 +156,10 @@ main(int argc, char *argv[])
   int orig_cwd_dfd;
 
   if (argc < 2)
-    {
-      fprintf (stderr, "usage: ostree-prepare-root SYSROOT\n");
-      exit (EXIT_FAILURE);
-    }
+    root_mountpoint = "/";
+  else
+    root_mountpoint = argv[1];
 
-  root_mountpoint = argv[1];
   deploy_path = resolve_deploy_path (root_mountpoint);
 
   /* Create a temporary target for our mounts in the initramfs; this will
@@ -303,6 +301,15 @@ main(int argc, char *argv[])
       perrorv ("failed to MS_MOVE %s to %s", deploy_path, root_mountpoint);
       exit (EXIT_FAILURE);
     }
-  
-  exit (EXIT_SUCCESS);
+
+  if (getpid() == 1)
+    {
+      execl ("/sbin/init", "/sbin/init", NULL);
+      perrorv ("failed to exec init inside ostree");
+      exit (EXIT_FAILURE);
+    }
+  else
+    {
+      exit (EXIT_SUCCESS);
+    }
 }