Function do_clone 

pub unsafe fn do_clone(ctx: &ucontext, event: &ShimEventAddThreadReq) -> i64

Execute a native clone syscall, creating a new thread, which may be in a new process (depending whether CLONE_THREAD is set).

If CLONE_THREAD is set, then the newly created child thread will resume execution from ctx, which should be the point where the managed code originally made a clone syscall (but was intercepted by seccomp). Otherwise this function will return normally in both the parent and child processes.

Safety

• ctx must be dereferenceable, and must be safe for the newly spawned child thread to restore.
• Other pointers, if non-null, must be safely dereferenceable.
• child_stack must be “sufficiently big” for the child thread to run on.
• tls if provided must point to correctly initialized thread local storage.