From: Robert Klemme <bob.news@...>
Date: 2004-09-15T20:19:54+09:00
Subject: Re: closing all open file descriptors


"Ara.T.Howard" <Ara.T.Howard@noaa.gov> schrieb im Newsbeitrag
news:Pine.LNX.4.60.0409141123490.29014@harp.ngdc.noaa.gov...
>
> 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... ;-(

Is it?

>> ObjectSpace.each_object(IO) {|io| p [io, io.class, io.closed?]}
[#<File:/usr/lib/ruby/1.8/irb.rb (closed)>, File, true]
[#<File:/usr/bin/irb (closed)>, File, true]
[#<IO:0x100ee000>, IO, false]
[#<IO:0x100ee018>, IO, false]
[#<IO:0x100ee030>, IO, false]
[#<File:/cygdrive/c/DOKUME~1/ROBERT~1.KLE/LOKALE~1/Temp/_usr_lib_ruby_1_8_
irb_lc_error_rb1464.0 (closed)>, File, true]
[#<File:/usr/lib/ruby/1.8/irb/locale.rb (closed)>, File, true]
[#<File:amakecr.bat>, File, false]
[#<File:/cygdrive/c/DOKUME~1/ROBERT~1.KLE/LOKALE~1/Temp/_usr_lib_ruby_1_8_
irb_lc_error_rb1464.0 (closed)>, File, true]
=> 9

Kind regards

    robert