Function setupPidfd

libcontainer/init_linux.go:724–737

setupPidfd opens a process file descriptor of init process, and sends the file descriptor back to the socket.

(socket *os.File, initType string)

// setupPidfd opens a process file descriptor of init process, and sends the
// file descriptor back to the socket.
func setupPidfd(socket *os.File, initType string) error {
	defer socket.Close()

	pidFd, err := unix.PidfdOpen(os.Getpid(), 0)
	if err != nil {
		return fmt.Errorf("failed to pidfd_open: %w", err)
	}

	if err := cmsg.SendRawFd(socket, initType, uintptr(pidFd)); err != nil {
		unix.Close(pidFd)
		return fmt.Errorf("failed to send pidfd on socket: %w", err)
	}
	return unix.Close(pidFd)
}