I am writing a server that uses long TCP connections (a mixture of plain TCP connections and TLS ones). Occasionally I would need to update the server software, so I replace the program’s executable file, save all the internel state that I need, and call syscall.Exec.

I would want the newly exec’ed server process to hold on to the previous process’s TCP and TLS connections.

1. Naturally what comes to mind for the TCP part, is to save the file descriptors and re-create them, via something like IPConn.SyscallConn to get a raw connection and to use RawConn.Control to fiddle with the file descriptor. However, RawConn.Control says “The file descriptor fd is guaranteed to remain valid while f executes but not after f returns.” How do I ensure that the file descriptor is still going to be valid?

2. How could this be done for TLS? How would I store the ephemeral state?