shutdown/shutdown.sh: failsafe shutdown for kexec

copy kexec from the real root, if it is not found in the unpacked
initramfs for shutdown.

Also drop to an emergency shell, if we can't do the ACTION

diff --git a/modules.d/99shutdown/shutdown.sh b/modules.d/99shutdown/shutdown.sh
index 74b6be8..1a6ac31 100755 (executable)
--- a/modules.d/99shutdown/shutdown.sh
+++ b/modules.d/99shutdown/shutdown.sh
@@ -12,6 +12,15 @@ export TERM=linux
 export PATH=/usr/sbin:/usr/bin:/sbin:/bin
 . /lib/dracut-lib.sh
 
+# if "kexec" was installed after creating the initramfs, we try to copy it from the real root
+# libz normally is pulled in via kmod/modprobe and udevadm
+if [ "$ACTION" = "kexec" ] && ! command -v kexec >/dev/null 2>&1; then
+    for p in /usr/sbin /usr/bin /sbin /bin; do
+        cp -a /oldroot/${p}/kexec $p >/dev/null 2>&1 && break
+    done
+    hash kexec
+fi
+
 trap "emergency_shell --shutdown shutdown Signal caught!" 0
 getarg 'rd.break=pre-shutdown' && emergency_shell --shutdown pre-shutdown "Break before pre-shutdown"
 
@@ -56,10 +65,20 @@ done
 _check_shutdown final
 
 getarg 'rd.break=shutdown' && emergency_shell --shutdown shutdown "Break before shutdown"
-[ "$ACTION" = "reboot" ] && reboot -f -d -n
-[ "$ACTION" = "poweroff" ] && poweroff -f -d -n
-[ "$ACTION" = "halt" ] && halt -f -d -n
-[ "$ACTION" = "kexec" ] && kexec -e
 
-warn "Shutdown called without an argument. Rebooting!"
-reboot -f -d -n
+case "$ACTION" in
+    reboot|poweroff|halt)
+        $ACTION -f -d -n
+        warn "$ACTION failed!"
+        ;;
+    kexec)
+        kexec -e
+        warn "$ACTION failed!"
+        ;;
+    *)
+        warn "Shutdown called with argument '$ACTION'. Rebooting!"
+        reboot -f -d -n
+        ;;
+esac
+
+emergency_shell --shutdown shutdown