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From: ebiederm@xmission.com (Eric W. Biederman)
To: Dave Hansen <haveblue@us.ibm.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>, Cedric Le Goater <clg@fr.ibm.com>,
       linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>,
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       Herbert Poetzl <herbert@13thfloor.at>,
       Sam Vilain <sam.vilain@catalyst.net.nz>
Subject: Re: [PATCH -mm 5/7] add user namespace
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Date: Fri, 14 Jul 2006 12:06:00 -0600
In-Reply-To: <1152897846.24925.83.camel@localhost.localdomain> (Dave Hansen's
	message of "Fri, 14 Jul 2006 10:24:06 -0700")
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Dave Hansen <haveblue@us.ibm.com> writes:

> On Fri, 2006-07-14 at 11:18 -0600, Eric W. Biederman wrote:
>> /proc/<pid>/fd/...
>> /proc/<pid>/exe
>> /proc/<pid>/cwd
>> 
>> It isn't quite the same as you are actually opening a second
>> copy of the file descriptor but the essence is the same. 
>
> Last I checked, those were symlinks and didn't work for things like
> deleted files.  Am I wrong?

Yes.  They are not really symlinks.

Wanting to have an executable that was deleted after it was done
executing.  I wrote it to a file. opened it, unlinked it, set close
on exec, and the exec'd it with /proc/self/fd/N.

Eric