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From:   Florian Weimer <fw@deneb.enyo.de>
To:     Laurent Vivier <laurent@vivier.eu>
Cc:     YunQiang Su <syq@debian.org>, torvalds@linux-foundation.org,
        gregkh@linuxfoundation.org, akpm@linux-foundation.org,
        viro@zeniv.linux.org.uk, James.Bottomley@hansenpartnership.com,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
        libc-alpha@sourceware.org
Subject: Re: [PATCH] binfmt_misc: pass binfmt_misc P flag to the interpreter
References: <20200306080905.173466-1-syq@debian.org>
        <87r1y53npd.fsf@mid.deneb.enyo.de>
        <8441f497-61eb-5c14-bf1e-c90a464105a7@vivier.eu>
Date:   Fri, 06 Mar 2020 09:37:31 +0100
In-Reply-To: <8441f497-61eb-5c14-bf1e-c90a464105a7@vivier.eu> (Laurent
        Vivier's message of "Fri, 6 Mar 2020 09:21:46 +0100")
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* Laurent Vivier:

> Le 06/03/2020 ? 09:13, Florian Weimer a ?crit?:
>> * YunQiang Su:
>> 
>>> +	if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0)
>>> +		flags |= AT_FLAGS_PRESERVE_ARGV0;
>>> +	NEW_AUX_ENT(AT_FLAGS, flags);
>> 
>> Is it necessary to reuse AT_FLAGS?  I think it's cleaner to define a
>> separate AT_ tag dedicated to binfmt_misc.
>
> Not necessary, but it seemed simpler and cleaner to re-use a flag that
> is marked as unused and with a name matching the new role. It avoids to
> patch other packages (like glibc) to add it as it is already defined.

You still need to define AT_FLAGS_PRESERVE_ARGV0.  At that point, you
might as well define AT_BINFMT and AT_BINFMT_PRESERVE_ARGV0.