From: Kent Sibilev <ksibilev@...>
Date: 2004-09-16T03:21:25+09:00
Subject: Re: closing all open file descriptors

On Linux, you can obtain the list of file descriptors by looking into  
the /proc/self/fd directory.

Cheers,
Kent.
On Sep 14, 2004, at 1:44 PM, Ara.T.Howard wrote:

>
> i just discovered a subtle bugette (no harm done except nfs silly name
> created) in some code i had written that is caused by forking with  
> open file
> descriptors followed by a close/unlink in the parent.  the child never  
> uses
> the file and so it's not really an 'error' - but on nfs this will  
> cause a
> sillyname to appear (.nfsxxxxxxxx) and remain until the child exits  
> which, in
> this case, can be up to five days later and i have dozens of these guys
> cluttering up my directories since this code runs on dozens of machine
> simoutaneously.
>
> i'm wondering - is there some way in ruby to obtain the list of all  
> open file
> desriptors so that something akin to fdwalk might be used to close all  
> open
> descriptors > fileno(stderr).
>
> all i can think now is
>
>   3.upto(65536){|fd| IO::new(fd).close rescue nil}
>
> which is incredibly expensive!
>
> you could set the close on exec flag of all of them too - but getting  
> the list
> of all open fds is just as hard... ;-(
>
> i've thought of tracking calls to open by supplanting ruby's  
> File#open, but i
> am using every extension which do their own opening too so this is  
> out...
>
> ideas?
>
> cheers.
>
> -a
> --
> ======================================================================= 
> ========
> | EMAIL   :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
> | PHONE   :: 303.497.6469
> | A flower falls, even though we love it;
> | and a weed grows, even though we do not love it. |   --Dogen
> ======================================================================= 
> ========
>