There are quite a lot of places in podman were we have some signal
handlers, most notably libpod/shutdown/handler.go.
However when we rexec we do not want any of that and just send all
signals we get down to the child obviously. So before we install our
signal handler we must first reset all others with signal.Reset().
Also while at it fix a problem were the joinUserAndMountNS() code path
would not forward signals at all. This code path is used when you have
running containers but the pause process was killed.
Fixes#16091
Given that signal handlers run in different goroutines parallel it would
explain why it flakes sometimes in CI. However to my understanding this
flake can only happen when the pause process is dead before we run the
podman command. So the question still is what kills the pause process?
Signed-off-by: Paul Holzinger <pholzing@redhat.com>
6bc52c9c5e