Issue #19347 has been updated by ko1 (Koichi Sasada). At the dev meeting there are 4 ideas: * 4 ideas * `Dir.fchdir(int)` * Proposed * Consistent to the POSIX API * Can be extended for `Dir.fchdir(dir)` and `Dir.fchdir(io)` * `Dir.chdir(int)` * Do not need to add new method * `Dir.chdir` partially implemented on Windows because fchdir is not supported by Windows. `respond_to?` is not usable to test the availability. * Can be extended for `Dir.fchdir(dir)` and `Dir.fchdir(io)` * `dir = Dir.for_fd(int); dir.chdir` * More object oriented? * 2 more methods (`Dir.for_fd(int)` and `Dir#chdir`) are needed * `Dir.for_fd(io.fileno).chdir` needs two objects (IO and Dir) references one FD. It would have a problem with GC. `closedir` frees DIR structure and closes FD. Thus, we cannot implement `autoclose: false` for `Dir.for_fd`. * Dir.for_fd(io.fileno, autoclose: false) * use dup(io.fileno) and close that, leave the original one alone? * `IO#fchdir` but not concluded. More discussions are welcome. ---------------------------------------- Feature #19347: Add Dir.fchdir https://bugs.ruby-lang.org/issues/19347#change-101352 * 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/