From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicholas Miell <nmiell@gmail.com>
Subject: Re: [patch 2/2] fs, proc: Introduce the /proc/<pid>/map_files/ directory
 v6
Date: Thu, 01 Sep 2011 19:04:42 -0700
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	Andrew Morton <akpm@linux-foundation.org>,
	Pavel Emelyanov <xemul@parallels.com>
To: Tejun Heo <tj@kernel.org>
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On 09/01/2011 06:58 PM, Tejun Heo wrote:
> On Thu, Sep 01, 2011 at 06:54:32PM -0700, Nicholas Miell wrote:
>> This doesn't seem to fully export all the information passed to mmap(2)
>> -- it encompasses the addr, size, fd and (assuming the generated
>> symlink's permissions are accurate) prot parameters, but does nothing to
>> export the flags or offset parameters.
> 
> It looks like,
> 
> /proc/*/fd : fdinfo ~= map_files : maps
> 

So are the filenames in /proc/$PID/map_files/ guaranteed to be identical
to the first field (first two fields? the part before the first space)
in /proc/$PID/maps?

When I open a file in /proc/$PID/map_files/, is offset 0 the start of
the file on disk or is it the first byte of the mapping?