For a user process, I want to mount a directory in other location but in user space without root privilieges. Something like mount --bind /origin /dest, but with a vfs wrapper. Like a usermode fine-tuned chroot.
The program would wrapper the syscalls to files to "substitute" the paths needed. It could be called with a command line like:
bindvfs /fake-home:/home ls /home
I am sure that this alredy exists! :)