m/n/c/update: allow kexec'ing the next slot
This allows asking the update service to stage the next slot into kexec,
allowing for kexec-assisted reboots.
Change-Id: I8aea80918ecbf714c3ae10462ee26bbc5bad0d2e
Reviewed-on: https://review.monogon.dev/c/monogon/+/3387
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/metropolis/node/core/update/update.go b/metropolis/node/core/update/update.go
index e4fbbbd..7c9e1c3 100644
--- a/metropolis/node/core/update/update.go
+++ b/metropolis/node/core/update/update.go
@@ -189,6 +189,35 @@
return nil
}
+// KexecLoadNext loads the slot to be booted next into the kexec staging area.
+// The next slot can then be launched by executing kexec via the reboot
+// syscall. Calling this function counts as a next boot for the purposes of
+// A/B state tracking, so it should not be called without kexecing afterwards.
+func (s *Service) KexecLoadNext() error {
+ state, err := s.getABState()
+ if err != nil {
+ return fmt.Errorf("bad A/B state: %w", err)
+ }
+ slotToLoad := Slot(state.ActiveSlot)
+ if state.NextSlot != abloaderpb.Slot_NONE {
+ slotToLoad = Slot(state.NextSlot)
+ state.NextSlot = abloaderpb.Slot_NONE
+ err = s.setABState(state)
+ if err != nil {
+ return fmt.Errorf("while updating A/B state: %w", err)
+ }
+ }
+ boot, err := os.Open(filepath.Join(s.ESPPath, slotToLoad.EFIBootPath()))
+ if err != nil {
+ return fmt.Errorf("failed to open boot file for slot %v: %w", slotToLoad, err)
+ }
+ defer boot.Close()
+ if err := s.stageKexec(boot, slotToLoad); err != nil {
+ return fmt.Errorf("failed to stage next slot for kexec: %w", err)
+ }
+ return nil
+}
+
func openSystemSlot(slot Slot) (*blockdev.Device, error) {
switch slot {
case SlotA: