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Date: Thu, 01 Sep 2011 18:54:32 -0700
From: Nicholas Miell <nmiell@gmail.com>
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To: Cyrill Gorcunov <gorcunov@openvz.org>
CC: containers@lists.osdl.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, Nathan Lynch <ntl@pobox.com>,
        Oren Laadan <orenl@cs.columbia.edu>,
        Daniel Lezcano <dlezcano@fr.ibm.com>,
        Glauber Costa <glommer@parallels.com>,
        James Bottomley <jbottomley@parallels.com>, Tejun Heo <tj@kernel.org>,
        Vasiliy Kulikov <segoon@openwall.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Al Viro <viro@ZenIV.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [patch 2/2] fs, proc: Introduce the /proc/<pid>/map_files/ directory
 v6
References: <20110831075814.003575573@openvz.org> <20110831080229.100652529@openvz.org>
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On 08/31/2011 12:58 AM, Cyrill Gorcunov wrote:
> From: Pavel Emelyanov <xemul@parallels.com>
> 
> This one behaves similarly to the /proc/<pid>/fd/ one - it contains symlinks
> one for each mapping with file, the name of a symlink is "vma->vm_start-vma->vm_end",
> the target is the file. Opening a symlink results in a file that point exactly
> to the same inode as them vma's one.
> 
> For example the ls -l of some arbitrary /proc/<pid>/map_files/
> 
>  | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80403000-7f8f80404000 -> /lib64/libc-2.5.so
>  | lr-x------ 1 root root 64 Aug 26 06:40 7f8f8061e000-7f8f80620000 -> /lib64/libselinux.so.1
>  | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80826000-7f8f80827000 -> /lib64/libacl.so.1.1.0
>  | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80a2f000-7f8f80a30000 -> /lib64/librt-2.5.so
>  | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80a30000-7f8f80a4c000 -> /lib64/ld-2.5.so

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.