shutdown: add new hook0.8.1

This adds functionality to pivot to back to the initramfs on shutdown,
thereby allowing the system to unmount the real root device. This will
be necessary for anyone with /usr as a separate partition.

1 files changed, 29 insertions, 0 deletions

diff --git a/shutdown b/shutdown
new file mode 100755
index 0000000..100f505
--- /dev/null
+++ b/shutdown
@@ -0,0 +1,29 @@
+#!/usr/bin/ash
+
+findmnt -Rruno TARGET /oldroot | awk '
+BEGIN { i = 0 }
+! /^\/(proc|dev|sys)/ {
+  i++
+  mounts[i] = $0
+}
+END {
+  for (j = i; j > 0; j--) {
+    print mounts[j]
+  }
+}
+' | while read -r mount; do
+  umount -l "$mount"
+done
+
+case $1 in
+  reboot)
+    type kexec >/dev/null && kexec -e
+    reboot -f
+    ;;
+  poweroff|shutdown|halt)
+    "$1" -f
+    ;;
+  *)
+    poweroff -f
+    ;;
+esac