linux-kernel - Re: support for limit of open file descriptors for a child process

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Message-Id: <1158247728.24835.20.camel@tara.firmix.at>
Date:	Thu, 14 Sep 2006 17:28:48 +0200
From:	Bernd Petrovitsch <bernd@...mix.at>
To:	Ram Gupta <ram.gupta5@...il.com>
Cc:	linux mailing-list <linux-kernel@...r.kernel.org>
Subject: Re: support for limit of open file descriptors for a child process

On Thu, 2006-09-14 at 10:21 -0500, Ram Gupta wrote:
> Hi,
>     I came across a problem regarding the issue of number of open
> file descriptors.The scenario is as below.
>  I have a controlling process which launches other different
> apllication including third party ones. It also enforces various
> resource limits including number of open file descriptors. This
> process forks & reads the resource limits from a configuration files,
> applies the resource limits & then execs for the corresponding
> application. The process has its own various number of open file
> descriptors. If the limit of open file descriptor for the child
> application is less than the number of file descriptors  of the parent
> process, then the child application file can not be opened & exec
> fails in this case.
> 
> I searched solution for this problem but could not find an existing
> way to solve it. I thought of couple of ways to do it. One idea is to

-) simply close(2) the superfluous file descriptors unconditionally
   before exec(2)ing the child process 
-) set the close-on-exec flag via fcntl(2) on these file descriptors
   after opening them

	Bernd
-- 
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