Add initial version of renumber backend

Renumber is a way of renumbering container locks after the number
of locks available has changed.

For now, renumber only works with containers.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

1 files changed, 16 insertions, 0 deletions

diff --git a/libpod/lock/shm/shm_lock.go b/libpod/lock/shm/shm_lock.go
index 87d28e5c1..e70ea8743 100644
--- a/libpod/lock/shm/shm_lock.go
+++ b/libpod/lock/shm/shm_lock.go
@@ -155,6 +155,22 @@ func (locks *SHMLocks) DeallocateSemaphore(sem uint32) error {
 	return nil
 }
 
+// DeallocateAllSemaphores frees all semaphores so they can be reallocated to
+// other containers and pods.
+func (locks *SHMLocks) DeallocateAllSemaphores() error {
+	if !locks.valid {
+		return errors.Wrapf(syscall.EINVAL, "locks have already been closed")
+	}
+
+	retCode := C.deallocate_all_semaphores(locks.lockStruct)
+	if retCode < 0 {
+		// Negative errno return from C
+		return syscall.Errno(-1 * retCode)
+	}
+
+	return nil
+}
+
 // LockSemaphore locks the given semaphore.
 // If the semaphore is already locked, LockSemaphore will block until the lock
 // can be acquired.