linux-kernel - Re: [RFC PATCH 0/2] Introduce a way to expose the interpreted file with binfmt

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Message-ID: <e673d8d6-bfa8-be30-d1c1-fe09b5f811e3@redhat.com>
Date:   Fri, 6 Oct 2023 14:07:16 +0200
From:   David Hildenbrand <david@...hat.com>
To:     "Guilherme G. Piccoli" <gpiccoli@...lia.com>,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc:     linux-mm@...ck.org, kernel-dev@...lia.com, kernel@...ccoli.net,
        keescook@...omium.org, ebiederm@...ssion.com, oleg@...hat.com,
        yzaikin@...gle.com, mcgrof@...nel.org, akpm@...ux-foundation.org,
        brauner@...nel.org, viro@...iv.linux.org.uk, willy@...radead.org,
        dave@...olabs.net, sonicadvance1@...il.com, joshua@...ggi.es
Subject: Re: [RFC PATCH 0/2] Introduce a way to expose the interpreted file
 with binfmt_misc

On 07.09.23 22:24, Guilherme G. Piccoli wrote:
> Currently the kernel provides a symlink to the executable binary, in the
> form of procfs file exe_file (/proc/self/exe_file for example). But what
> happens in interpreted scenarios (like binfmt_misc) is that such link
> always points to the *interpreter*. For cases of Linux binary emulators,
> like FEX [0] for example, it's then necessary to somehow mask that and
> emulate the true binary path.

I'm absolutely no expert on that, but I'm wondering if, instead of 
modifying exe_file and adding an interpreter file, you'd want to leave 
exe_file alone and instead provide an easier way to obtain the 
interpreted file.

Can you maybe describe why modifying exe_file is desired (about which 
consumers are we worrying? ) and what exactly FEX does to handle that 
(how does it mask that?).

So a bit more background on the challenges without this change would be 
appreciated.

-- 
Cheers,

David / dhildenb