🚀 go-pugleaf

> Since directories in the Unix file system are required to have "."
> and ".." entries, it does not make sense to permit their removal.

I tend to agree, but consider this from the S5R3 "mvdir.sh" script:

	/etc/unlink $t/..

which is required if you are to move directories from one containing
directory to another.

> The best solution would seem to be to use system calls to create
> and remove directories, instead of super-user privileged processes
> that invoke link(2) and unlink(2).  This also lets you avoid race
> conditions that the latter approach is heir to.

The same is true for moving directories.  A "rename(2)" system call
permits you to move directories in unprivileged programs without
having to invoke a privileged directory-moving program.  It also
obviates the need to allow users to remove or create ".." links.

> Current BSD and System V releases have mkdir(2) and rmdir(2) calls.

Current BSD releases have "rename(2)", and since "rename" is in POSIX
future System V releases will probably have it as well.