Merge pull request #48 from swick/patch-2

wishlist: add AT_EMPTY_PATH to openat()

Author: brauner

README.md

@@ -697,6 +697,19 @@ tells userspace that there was an fd, but it was not allowed through.
 
 **Use-Case:** Any code that wants to use `SCM_RIGHTS` properly.
 
+### `AT_EMPTY_PATH` support for `openat()` and `openat2()`
+
+To get an operable version of an `O_PATH` file descriptors, it is
+possible to use `openat(fd, ".", O_DIRECTORY)` for directories, but
+other files currently require going through
+`open("/proc/<pid>/fd/<nr>")` which depends on a functioning `procfs`.
+
+FreeBSD already has `O_EMPTY_PATH` for `openat`, while `fstatat` and
+similar functions have `AT_EMPTY_PATH`.
+
+**Use-Case:** When dealing with `O_PATH` file descriptors, allow
+re-opening an operable version without the need of `procfs`.
+
 ---
 
 ## Finished Items