Sharing file descriptor table with child after child has done an exec

Question

Is there any way to create a new process which shares your file descriptor table even after an exec? clone(CLONE_FILES) won't work, as the man page says:

If a process sharing a file descriptor table calls execve(2), its file descriptor table is duplicated (unshared).

Answer 1

This can be done by injecting into the child process a custom piece of code responsible for the receival of FDs and updating the child's descriptor table.

Child process should create AF_UNIX socket and recvmsg() on it, while parent process should duplicate and "stream down" the required file descriptors using sendmsg() - see here