From: KOSAKI Motohiro <kosaki.motohiro@...>
Date: 2013-02-20T15:32:58+09:00
Subject: [ruby-core:52567] Re: [ruby-trunk - Bug #7879] File.readable? fails when ruby runs as root

>> You need specific concern when opening /proc, /sys and similar pseudo filesystem's file.
>
> Out of curiosity, what should we concern concretely?  Should we assume File.readable? as a hint?

Pseudo filesystem hae several exceptional rule. this is one of them.
So, yes, when you can touch pseudo filesystems, I don't recommend to
use File.readable?. This is OS limitation and we can not fix them.