From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2004-09-15T02:44:53+09:00
Subject: closing all open file descriptors


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
--
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| EMAIL   :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
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