Add ability to clean up exec sessions with cleanup

We need to be able to use cleanup processes to remove exec
sessions as part of detached exec. This PR adds that ability. A
new flag is added to `podman container cleanup`, `--exec`, to
specify an exec session to be cleaned up.

As part of this, ensure that `ExecCleanup` can clean up exec
sessions that were running, but have since exited. This ensures
that we can come back to an exec session that was running but has
since stopped, and clean it up.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/docs/source/markdown/podman-container-cleanup.1.md b/docs/source/markdown/podman-container-cleanup.1.md
index 66a6cff62..a200c2c36 100644
--- a/docs/source/markdown/podman-container-cleanup.1.md
+++ b/docs/source/markdown/podman-container-cleanup.1.md
@@ -16,6 +16,13 @@ Sometimes container's mount points and network stacks can remain if the podman c
 
 Cleanup all containers.
 
+**--exec**=_session_
+
+Clean up an exec session for a single container.
+Can only be specified if a single container is being cleaned up (conflicts with **--all** as such).
+If **--rm** is not specified, temporary files for the exec session will be cleaned up; if it is, the exec session will be removed from the container.
+Conflicts with **--rmi** as the container is not being cleaned up so the image cannot be removed.
+
 **--latest**, **-l**
 Instead of providing the container name or ID, use the last created container. If you use methods other than Podman
 to run containers such as CRI-O, the last started container could be from either of those methods.