Enhance fifo's sync between 'runc init' and 'runc start'

[jokemanfire]

hope to add authentication mechanisms to the synchronization of exec.fifo.
Why? Because while the init process is waiting, any process reading exec.fifo will cause init to proceed to the next step. For example, grep-R disk scanning operation. This can lead to errors in upper level applications, as run init has completed normally, but the start process has not yet started or is currently in progress.
I have achieved Fifo certification for Rust with my limited knowledge. Welcome to discuss further.
rust safty fifo impl