Issue #19347 has been updated by matz (Yukihiro Matsumoto). I agree with having `Dir.for_fd` and `Dir#chdir` as well. If the assumed use-case is handling a file descriptor sent via UNIX domain socket, allowing `chdir` only is not sufficient. We should allow other directory-related operations via `Dir` class. Matz. ---------------------------------------- Feature #19347: Add Dir.fchdir https://bugs.ruby-lang.org/issues/19347#change-101726 * Author: jeremyevans0 (Jeremy Evans) * Status: Open * Priority: Normal ---------------------------------------- Recently, I was working on a program that passes file descriptors over UNIX sockets (using `send_io`/`recv_io`). For file/socket/device descriptors, this works fine using `File#reopen`. However, I found that while Ruby supports `Dir#fileno` to return a directory file descriptor, it cannot use that file descriptor when changing directories. I worked around this in my program by writing the directory path over the UNIX socket, but this results in a TOCTOU vulnerability in certain cases. Passing the directory file descriptor would be simpler and avoid the vulnerability. I've submitted a pull request to implement this method: https://github.com/ruby/ruby/pull/7135 -- https://bugs.ruby-lang.org/