Is there a way to inspect the files and directories of another mount namespace?
setns(2) syscall appears to be able to move a thread to another namespace, but if this functionality is not already built in to a program (a shell, fileserver, ..), it appears that executing a new process is required. And since the target mount namespace may not contain the required binary, this is a problem.
What I am looking for is a "user-friendly" way to access the files in the namespace. I can imagine there being, for example, a way to mount the namespace somewhere on the host system. But since I don't know what's possible, I'm asking.