Add a -k option to reboot to specify the kernel to boot next time

around.  If the kernel boots successfully, the record of this kernel
is erased, it is intended to be a one-shot option for testing
kernels.

This could be improved by having the loader remove the record of
the next kernel to boot, it is currently removed in /etc/rc immediately
after disks are mounted r/w.

I'd like to MFC this before the 4.6 freeze unless there is violent
objection.

Reviewed by:	Several on IRC
MFC after:	4 days

1 files changed, 4 insertions, 0 deletions

diff --git a/etc/rc b/etc/rc
index c5e7d53..ed4ceea 100644
--- a/etc/rc
+++ b/etc/rc
@@ -314,6 +314,10 @@ if [ -n "${diskless_mount}" -a -r "${diskless_mount}" ]; then
 		sh ${diskless_mount}
 fi
 
+# If we booted a special kernel remove the record so we will boot
+# the default kernel next time
+rm -f /boot/nextkernel
+
 # Reseed /dev/random with previously stored entropy.
 case ${entropy_dir} in
 [Nn][Oo])